CA2080962A1 - Adjusting mechanism for a chair-mounted computer input device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An adjusting device embodying the concepts of the present invention is incorporated in a mount by which a tray assembly adapted to support an input device for a computer is supported from a chair. The proximal end portion of a mounting bar is supported from a chair such as that the mounting bar is disposedsubstantially horizontally form the chair. A substantially vertically disposed support assembly is rotatable mounted from the distal end portion of the mounting bar. The first end portion of an arm assembly is supported for articulation from the pivot assembly about an articulating axis that is disposedsubstantially horizontally. A tray assembly is pivotally supported from the second end portion of the arm assembly about an pivotal axis that is disposed substantially horizontally. Means may be provided selectively to establish the distance between the mounting bar and the articulating axis. Locking means may also be provided selectively to secure the pivotal position of the tray assemblywith respect to the arm assembly, the articulated position of the arm assembly with respect to the support assembly and to establish the distance between the mounting bar and the articulating axis.

Description

ADJVSTING M~CHANISM FOR A CHAIR-MOUNTED
COMrVTI~ lN~UT Dr!,VlCE, The presenl invenlion relalcs ~ener.llly to computer worl~ station furnilure. More pDnicul;lr1y the prcscn~ invention rela~es to a ch~ir-mountcd tray assemb1y by whiel~ to supporl a eompuler inpul device. Speciric~lly the present invenl;on rclnles lo an ;l~ljus~in~ mechanism by which to select the dispDsilion of thc Iray ;Issembly relalive lo Ihe chilir from which it is mounted for the maximum eonvenienee ot the person se~te~l in thc ch;lir Here~ofore the furnilure av3il~ble for eompuler operators provided for in~lepen~ent ~(Jjussmenls Or Ihe eompuler monilors ~n(l inpul ~Jevices relalive to the IJesks on nr frnm which ~I)ey were supporle~3 The ehair 2t a work s~alioncoulLI or course he a~ljusled independenlly of ancl thererore rel;~tive lo lhe desk on which thc compuler etluipment was supporle~l Neverlheless it must be appreci;lle(l lhat nn maller llow m;lny in~livi~lu.ll ;~ljuslmcnts were provi(le(l such arran~ements efreclively immol)ilize thc operalor while operatin~ the computer.
That is the proper re~islr;llion or lhc oper~lors han~is wilh respcct to thc eomputer input (levice c~n he maint~ine~ only so lon~ as the chair on which the oper~tor is se~te~l ~loes nnt move rel.ltive to Ille in~lcpendenl desl; or otherstructur~l arr~n~ement frnm which lhe input ~levice is supporte(l In;~smuch as the atores;~iLI re~istr~!inri of lhe eomputer operalor relative to lhe coml)uler ~n~l particul~rly the inpu~ clevice ls ~eeomplishe~ y in~lcpen~lenlly posilioning notonly the compuler compl>nen~s rcliltive lo Iheir suppor~in~ dcvi~es b~ 150 the ch~ir rel~ive to the suppnr~ing IJevices for lhe eomputer componen~s the compu~er operator can not rock or swivel in the chair while workin~ wilhou( v~rying Ille parlicul~r re~islr;l~ion ~lesired by lhal p~rticular opcr~lor. And yc(, frequcn~ movemen~ of tllc r.)per;ltor is highly llfsir;lhle. Il has been rolln~l that movemen~ of ll-e nr>crn~or enh~nces circulil~ion ~nLI rc~luces the str.~in, sension and musclc cr~mpin~, so oflen expericnce(l when opcr;llin~, compulers for long 2 ~ ?

- ? -perio~ls of ~ime. ~mmohilily, on Ihe oll-er h~nlJ, lca~Js ~o physic~l sliscomrort, and occasional disabili~y.

Jt is, ~hererore, a pr;mary Dbject or Ihe presen~ invention to provid~ an ~rran~ement whcrehy Ihe c~mpu~er input (levice is supportcd direclly trom the ehair in which t7)c computcr operalor sits in or-ler lo assure rcgistrali~n between the computer or)erator 3n~1 ~t least thc computcr inpul ùevice, irrespeclive of how much the oper;llor may move, rock or swivcl, in the chair.
It is anolher ohject of the present invention to provide a mechanism by which to ndj~lst ;I chair-mounlc~l Iray ;Issemhly upon svhich a coml~uler input device m~y be sllpported.
It is a further ol~ject of Ihe present inven~ion to provide an adjusting mechanism, ~s al)ovc, whicl) permils thc tr:ly ~sseml)ly ~o l)e selectivcly Llisposed ~re ~ncl ~ft with respcct lo ll)c operalor by movemcnl ot ~he tr~y ~ssenlbly abou an articulating axis.
It is a still fllrll)cr nl)jc.ct nr tl)e prcscnt invcnlion to l7rovidc an adjustin6 mechanism, as ahove, whicl) permils Ihe tray IO be seleclive1y îilletlabout a pivolal a~ds thal is displaccd rrom thc arliculalin~ ~xis.
~ 1 is ycl anolller ohjccl of Ihe prescnl invcnlion lo provide ;In adjusling mechanism, ~s above, ~rari~lions ot wllich may permil the articul;lting 3xis to be selectively displacetJ in a vcrlic~l sJirection.
Jl is ~ sti~l Furtller object Or Ihe presen~ invenlion to yrovide an fidiusting mcchanism, ~s aboYe~ varialion3 of which m~y permil seleclive adjustmenls wilhoul the nee~J for mnnipulatin~ 3 lDci;ing aclu~lor.
It is an even f~;rther object of Ihe presenl invention lo ~rovide an adjustin~ mechanism, ;~s ~bove, variations of which may permit selec~ive adjus~ments by operalin~ a sin,~le locking ~c~ual~r.
It is an aslditi~n~l ohjccl ot the prcscnl inven~ion to provide an - ~djustin~ mech;lnism, ;1~ al~nvc, vari;llions of whicll may perrnil seleclive adjus~menl by operaling du;ll lockin~ nclu~lors.
Thcse ;In~J other ohjccls Or the invenlion, ;Is well ~s lhe a-lvanta~es thereof over existinS and prior arl forms, which will be ;Ipparenl in YiCW of Ihe X~ i?~

followin6 dc~;lilcLI speciric~ion are ~ccomplishcll by me~ns hereinafler describeLI
and clalirned.
~ n gencral an ~djuslin~ mechanism embodyin~ the concepts of ~he presen~ invenlion is incorpor~teLI in the s~ructtlrc hy which a ~ray ~ssembly ismDunled from a ch;lir. The proximal en~l portion of a rnoun~ing b~r is securcLI to a chair such ~hat Ihc moun~in~ bar i5 disposed sIlhs~nli~lly horizont;llly. A
subst3nti~11y ver~ically disposed support assembly is moun~ell from ~hc dis~l cnd porlion Df Ihe mnunting b3r 3n~1 lhe sul-porl asscml)ly m ty be rotal~l)le about ~
venical LXis it (Jesired ~o facilita~e enterin~ ~nd cxitin~ the chair. The firs~ end portion or ~n arm ~sseml)ly is sllpporte(l for ~r~icul:l~ion rrom the pivnl ~ssembly and ~ ~ray assemhly is pivo~lly s~lpporlc~l from Ihe secnnd en~ porlion of Ihe arm asseml)ly.
Onc excmplary emboLlimen~ of ;In ~djus~in~ mechanism - and se~eral v~ri~lions - of ;I ch~ir-mnllnled tray tssemhly ad~pled to supporl an input clevice for A compuler arc descril~ed in sumcienl dc~ o errect a rull disclosure of the subject invcntion. The exempl~ry a~ljusling mech;lnism anLI îhe ~riations thereof are descril~e~l in dcl~il will1oul allemplin~ to show all of the variousforms ~nd modiricntions in wl-ich thc invcnlion mighl be embodic~l; thc invention bein~ measurcLI l~y the ;~ppenLlc(l cl;lims ;lnLI not l)y thc de~.lils or ~he specificalion.

FJG. ~ is a siLlc elev~tion nr ~ ch~ir with ~ supportin~ tr~y zssembly mountcd thereon by i~n 3djuslin~ mcch3nism which incorpor3$es the eoncepls of the prcsenî invcnlion;
FIG. 2 is ;I top pl~n view Or ~he ch~ir ~Icpicte~l in F~G. 1 anli wi~h the Ir~y asserr!l)ly dcpicleLI in Ihe workin~ posilion in ~oliLI line DnLI in Ihc ~ccess pQsiîion hy whicl) to f~cili~ e cnlry an~l exi~ Or II)C opcraîor rrGm tllc chair in chain line;
FIG 3 is an explo~Je~l perspeclive depic~in~ a mcun~ing l~;lr th~ is a~apletl tD be sul~slan~ y llorizon~;llly suppor~e~l from Ihc chair a slll)slanlially vertically disposc~l support 3ssemhly Ihat is rot.tt~hly sllpportcll from thc mounting b~r an arm DSS mhly îhtt is suppor~e~l ror ~rliculation rrom the -4 ~

support ;~ssembly ~nd ~he frame por~ion Or lhe tray ~ssembly lhat is pivotally supporte~ from the arm asscmhly -- thc D~ljuslments in Ihc thYee sJircctions designated by the arrows in I~IG. 1 being ~v~ilal)le by ~ppropriale ~clu~tion torcle lse or en~ c tl lockin6 mech.lni5m Willl 3 sin~lc il~ljuslmcnl con~rol knob;
FJG. 4 is an enl;~rged verlicDI seclion l~ken substan~ia11y ~lon~ line 4-4 of l:IG. 3 ~o clcpict ~hc inlerrelalionship bet~veen the struc~urc ot Ihe arm asscmbly ;Ind tlle s~mclllrc Or Ille supporl ~s~cmbly ~s well ~s betwcen Ihe struclurc of Ihe arm ~ssemhly an~l Ihe stmclllre o~ the tr~y assembly;
FIG. 5 is a view simi1ar to FIG. 3 but wi~h ~he verlical support ~ssembly represenlcd as hDvin~ been ~sscmhle(l lo ~hc mounting bar an~J wi~h a number of ~he componenls in Ihe supporl assembly as well ~s ~ number of cornponen~s in ~hc arm ~sscml~ly h;lving alsn been ~ssemblc~l;
l;IG. 6 is a view simil~r ln FIGS. 3 an~ 5 bul with ~11 the somponen~s h~ving bcen ;Issemblcd;
FIG 7 is ;I view similar to FIG. 6 bu~ with ~he Drm ~sseml)ly having becn arliculDtc~l witll respcc~ to Ihc sul~p()r~ Dssembly in or~ler ~o movc Ihe tr~y assembly fonv~r~lly ~n~l with the tray 3ssembly l);lving been pivotcd ~o rem~in substanti311y horizont;ll;
I:IG. 8 is an explo~led ~)crspeclivc Or a v;~ri;ltion Or the emho~liment depicled in ~I~S. 3 ll-rou~ll 7 in tll~ Ille ~(ljusling mech;lnism is controlle~l by a 2 o levcr;
FIG. 9~ is Dn cnl~r~ed horizontal scction ~aken substanti;llly along the reference line 9-9 in l:IG. 8 but with ll-e relcase ~ctuator recei~e~l wilhin an appropria~e recess in Ihc frame of ~he Iray ~ssem~ly and wi~h ~he inlerrcl~te~l structural componen~s h;lvin~ heen ;~sseml)lesJ ~o represenl their disposilion wilh the locking mcchanism in Ihc cngD~e~l modc;
FJG. gn is ~ vicw simil;lr ~o l:IG. 9A but with the ~elcasc ~ctua~or having been swun~ by ~I-c Ie~lrer lo tJepict Ihc disposilion Or lhe locking mech~nism in the rele:~sc mo~lc;
FIG 30 is an explo~le(l perspeclive Di` a fur~her v~ri3lion of the adiuslin~ mech~nism in tll3l ll-e l~cking mech3nism is ~cluate~5 by twc knl)bs one selcclively to control ~rlicul.ltion of Ihe ;Irm ~sseml~ly 3nul ~he verlical posi~ion Ihereof ~n(l Ihe secon~ lo con~rol pivo~l movemenl of tlle Iray assembly;

~ IG. 11 is an explotled perspeclive of ilnother v~riiltion in which the IDckin~ mechilnism ~41lich con~rols pivo~l adjus~ment of thc ~r~y nssernb1y is sprin6 biased lo ~crmi~ pivo~al a~ljustmcnl Or shc ~ray ~s~cmbly wi~hout eithcr a lcver or a knob ~c;n6 rcquired to ac~uiltc lhe 10ckin~ mechanisrrl but the locking mechilnism which conlrols articuliltion of the ;l~m ~ssembly and the ver~icill position lhereot is actuatcd by in knoh;
l:IG. 12 is an cxploded perspectivc of a fur~her variation wl)crçin 1he loc~iin~ mechanism for cnn~rolling articulation pivo~ill movement and elevation of the lray asscmhly arc ac~uilted by a single knoh;
FIG. 13 is an cxplodet3 perspcctive of a 5till further v~3ria~ion of the adjuslin~ mecllanism in thil~ thc lockin6 mechanisn1 whicl) con~rols arliculation of the arm assemhly an(l pivolal movemen~ Or lhe ~ray assembly arc bo~h spring biilse(l to permi~ thosc a(ljustmcnts witl~oul Ihc nccc~ily to ac~uale ci~l~er a lever or a knob while elevalion is fixed;
FIG. 14 is an exploded perspec~ive Or an cven fur~her varia~ion wherein Ihe locldn~ mecllanism for con~rollin~ ar~icul;l~ion of ~bc arm nssemblyand pivo~ill movemen~ o~ thc tray Asseml)ly are ac~uiltetl by a singlc knol~ locatct3 in proximity to one end of ~lle arm asseml)ly while eleva~ion is fice~l;
l:IC. lS is an cxplode~l perspcc~ive Or a vari.3lion Or Ihe eml~odiment depicled in FJG. 14 whcrcin ~hc lockin~ mccllilnism ror con~rollin~ artic~ ion of ~he arm assemhly and pivo~AI movcmen~ of the triy assembly are individually Dclualed hy sepilrillc knobs one for conlrollin~ .3r~icul~1ion of the nrrn assembly and one for controlling pivo~al rnovcment of the tr;ly .3sseml~1y; .3nd l:lG. 16 is an explot3cd perspec~ive o~ a fIlrlher vari3tirn sf Ihe embodimen~ depiclcd in ~IGS. 14 an~l 15 wherein the locking mcchanism for contr~llin~ ar~iculillion or ~he arm ~ssembly il1n~3 pivDtill movemen~ of ~hc tray assembly are ~ctuilted l~y a sin~le knob locille(i cenlr~lly of the arm ilssembly.

Represcn~ative forms Or an alljuslin~ mechilnism for a chilir-moun~e~l arranBement hy which ~o ~lpp()rt ~ 1easl ~he inplll (levice for ~ com~)uter are clesigna~e~l generAlly by the numeral ~0 on 1he 3ccomp;~nyin~ llrawin~s One form of an cxemplary atlj~s~in~ mcchanism i~lcnlirie-l by lhe alph;lnumeric ?

desi~nalion 1~ an~l as (Iclaileù in T:IGS. 3 tl-rougl) 10 inclu~les ~ mounling b~r Il ~ verîic~t sllppoll asscmbly J2 an ;~rm assembly 14 an~l ~ tray asscmbly I5.
The proximal enLI por~ion ~6 (~:IG. 3) D~ the mol~n~in~ b~r II is securc-l to the un~lerside 17 of ~ chair sc~lin~ framc ~8 (li:IG. 1)~ an~ thc dis~al enù p~rtiDn 20 Or lhe mountin~ b:lr Il ~Icrines ~ ~ertic~lly eltlcn(lin~ rot~ional ~xis 21 (PJG. 3) with respec~ tD which the ~erlically s.lisposc~l suppor~ ~ssembly I2 is rot~!~bly sllpporle~l. Thc supporl nssembly ~2 presen~s ;l sul-sl~n~ lly horizonlal articula~ion ~(ljuslmenl nxis 22 wilh respecl lo which the arm assembly 14 is moun~ed for nrticul;ltion. Tlle ~rm assembly 14 ~Iso presen~s a substantially horizon~al pivot axis 24 ~hout wl-ich the tr~y asscmbly ~5 may be a(ljustably ~ e(l. In ~d~ ion supp(lrlin~ assembly 12,~ incorpora~es means by which the articul3tion a~ljustment ;Ixis 22 antl lhererorc ~hc horizont;ll pivot ~xis 24 can be vertically a~justc(l.
Thc present invention is ~lisclose~ in conjunclion wi~h a numbcr of variations. As such in Ihe dctailcll ~lescription which follows a p~rlicul~r structural meml)cr comp()ncnt or ~rran~emenl may he employell in more ~han one varialion Or lhc a(ljuslin~ mecllanism or cvcn nt more ~h;ln one location in a parlicul~r ~!aria~ion of lhc a~ljus~in~ mcchanism. When rcferring generally to that type Or struclural membcr componcn~ or ~rran~emcnl a common numerical dcsigna~ion sh~ enerally be emplnye(l in e;~cl- of ll~e sevcral variations described hercin. IloweYcr whcn one Or the struclllr;ll members coml)onents or arran~emcnts so i~lcntiric~l is empk)ye(l ;It n1orc tllan one loc~tion in ~ sin~le variation nn~l th;lt component is to bc in~liviLlually i~lentified it sll~ll be referenced by virlue of ~ letter surfix employetl in combina~ion wl~h the numerical design;llion employclJ ~or ~encr~ lcn~ificalion of lh~ struc~ur~l membcr componen~ or ~rr;ln6cmcn~. ~s ;m cx;lmplc Or lhis usa~e two key v~ys sh~ll be suhsegllen~ly ;~lcntirie~l on one v,~riation, .In~J those keyways will havc ll-c same stn)cture. J~s such, the keyways shall he ~eneric;llly idenlifie~i by the nurner;ll ~S, hut lhc spccific keyways sh;lll he indivi~ lly iLlentified cls 8SA an~
85B, hoth in ~he spcciric;llion ~n~l nn Ihe ~lr;lwin~,s. Thcrc ~re ~Iso two s~ructural vari~tions of ~he verlic;ll suppnrl ~s~emhly which shall be ~eneral!y i~Jen~itied by the number l2. ~Sr~wever, thc ~wt) ~pcci~ic conri~llr:l~ions Or tha~ com~oncn~ sha51 be il~cntified by a Icltcr suffix ~vhich sllilll hc represen~e(l S15 O. sllbsCript.

~9~?

Accor(lin~ly the specific indivi(lual v~ri~lisns of lhc suppor~ asseml)lies shall be identiried ~s 12~ ~n(l 12~ bo~h in lhe specirication ~nd on ~hc drawings. This same suftix convcn~ion sh~ll be cmploye~l ~hrou~hou~ the specifica~ion.
Wi~h p~r~icular retercnce to ~hc prim~Ty embodimcnt which is prcsen~ctJ in ~lelail in FlGS. 3 lhrou~h 70 the mounting bar 11 is depicscd as havin~ a pair of mounting hores 26 ~n~l 27 ~hrou~h which ~ p~ir of 1~2stener5 28an~l 29 respeaivcly exlend ~nd hy which Ihe mounting b3r m~y be secured to thc l~ndcrside 37 of the clu.~ir seating trame 18 (~SG. 1). The mounting bore 26nearest ~hc proximal cn~l porlion lh of ~he mountin~ b:lr 11 may bc l~tcr~lly elong~tc(l to permit somc ~lljustmcnt to Ihc prccisc oricnt31ion o~ lhc mountingb~r 11 on Ihe chair se3lin~ frame 1~. The dist;ll cnù portion 20 of ~he rnounling bar 1I tcrmin;lles in a bulholls porlion 31 whicll presenls ~n upw~r~Jly f~cing subslnnli~lly llat s~lrf~cc 3s2 h~ving n s~ ;lnli;~lly ccnlr~l circul~r opening 33 through which the rot;lry .~LXis 21 extcnds.
A gukle har or supporl ro~3 34 is receive~l in the circul~r opcning 33 and extends vcrlic:ll1y upwar~l1y rrom the mounling bar 11. Prcferably the lowerend 35 Or the guidc b~r 34 is rlxe~lly sccurc~l wilhin ~he openin~ 33 in orùcr to provide ~ struclurill arrangemenl hy which thc rem~ining components c~rrieù b y the mounling bar 11 m;ly bc proviulc~l wilh later;llly s~bili~y A rirs~ ~ui~le tube 36 surro-ln(ls the gui~le l).lr 34 is treely rol;llable ~hereon ~nd h~s ~ lower end 37 thal is secureù in a lowcr luhc rcl.lincr 3~. Thc upper end 40 of Ihe tirsl gui~le tube 36 is tillc~l in ;~n upl-cr lul)e rcl;lincr 41 which m:ly l)c ro~alal~ly secure~l to the guiLle b~r 34 by a Ihrca~Je~l taslcner 44 ~ second guiLle lul)e 42 is also ~ecured at its resr~eclivc l~pper ~nd lower en~s 45 ~nd 4G in Ihe upper ~ube ~et~iner 41 anLl Ihc lowcr luhc rcl;~incr 38 The lowcr ~lbe ret~iner 38 h~s an enlargcd portion 48 which sl~rrollrl~1s ~he lower cn~l 37 of Ihc firs~ gui~le subc 36.
E~tcnding l~ter~lly o~ltw;lr(lly from lhe enl~r~c~i portion 48 is ~n clongate~l portion 49 which lcrmin~es in ~ rounLleù end portion 51 An opcnin~ 52 penetr~es ~he rountlc~ entl por~ion 51 an(l ~he lower en~l 46 of lhc ~uidc tu~e 42 is received in lhc openin~ 52. ~ Ihrus~ wa~llcr 54 is llispose~J betwcen the lower tube retainer 3R ~n(l Ihe upw;lr~lly racin~ surr;lce 32 on the moun~in~ h~r 11. Thc Ihmsl washcr 54 provi(les ~ low fric~ion inlerrace between the ver~ical supporl ~sseml~ly l2A an(i II-e mnunling bar 11 to racili~ e posi~ioning of lhe - B -Supporl assernbly 12A rcl llivc lo (he mounlin~ h;lr 11 ;In~l abou~ 13)e vcrlically orienled, rot;llional ~xis 21.
A convcn~ional delcn~ assemhly 57 may be mountecl ;n ~ rcceiving bore 59 provillccl in Ihe elongalccl porlion 49 of lllc lowcr ~llbc rclainer 3R. The detcn~ nsscmbly 57 includcs a convcnlional s~ring-biasc~l ball member 5~ which coopcra~es with reccsscs 60A nnd 61A incorpr~r;~ed ;n thc upwar(lly f~cin~
surfacc 32 on the bulbous por~ion 31 Or ~hc moun~in~ bar 1I to eslablish Ihc twolimit posilions bctween which the verlic~l ~upporl ~ssembly 12~ may bc ro~atel~.A tr~ck 62A exlcn[3s betwecn thc rccesses 60A ancl 61A ~o guille lhe ball member 58 during rol~lion of Ille sllppnrl assemhly 12~ between lhc Iwo limit posilinns. A seconci pair o~ recesses 6û~ ancl 61B 3s wcll as a ~r~c); 62B are provicleLI in the upwardly f~cin~ surrace 32 for provi~ling positioning of the verlic~l supporl ;Isscmbly 12~ whcn Ihc mountinl bar ll is securc~l in Ihe oppositc (lirec~ion on Ihc ~mderside 17 Or lhc chair se;lting rrame ~8. Thlls lhc same mounlin~ har 1~ m~y be used to ~ccommn~ e bolh Ic~t and righl hand confi~lratiorls irrcspcc~ivc t.r whc~llcr desircd wilh respecl to thc manufaclurc of origin;~l equipmcnl or ror in-ricld conversinns Illcreby reducin~ the n~lmber ofcomponen~s required in inven~ory.
A vcrlicnl ~djus~men~ ~Isscmhly fi4 is mounleLI on lhe ~uidc tubes 36 and 42. Tlle vcrlical acljuslmenl ~ssemhly includcs opposed rirsl and sccond slide blocks 65 ancl 6G securc~ logelllcr hy Ihrc;)~Je~l r~slcncrs G7 antl h8 an~l their ~ssocialell nu~s 69 and 70 The hcx nuls 69 ~n(l 70 arc receivecl in hex~gonal openings 72 an(J 73 respeclively rormed in the second sli-le block 66 ~nd the faslenèrs 67 ancl 68 p355 ~hrougll cylindrical openin~s 74 and 75 rcspecliYcly which pene~ra~e thc firsl slicle bloc~; 65 opera~ively lo engage the nu~s 68 and 70 The ~Irs~ slitle block 65 h~s a plur31ily o~ cen~r;ll na~ surfaccs 77 prcsenled on ei~her sille of !he openin~s 74 an~l 75 ~s well a5 n~t outcr c~l~es 7B and 79. The secon~l sli~e block 66 h~s mirror ima6e sllr~ccs ;Inll e~es which cooreratc wi~hthe surf~ccs 77 ;~nll lhe e~ es 7~ ~rt~l 79 on ~I)c firsl sliLlc block 65 (o m~int~in the av~ilul-ilily o~ ~1 slidin~ r~l l)el~een tllc sli~lc l~locks G5 ~nd 66 ~nd ~llc guiùe tubes 36 ~ntl 42 evcn wllcn thc slidc hl(>cl;s fi5 ;Inù f,() ~re eonjoinc(l by ~he fastencrs 67 ~n~ 68 The sli~ing fi! t)elween Ihe asseml~le~l slidc hlocks 65 ~nd 66 and the guide tubes 36 nn~l 42 may howcver be scleclivcly ncg;l~ed to pcrmil one lo move the ~sscmble~l sl;~le blocks lo specific Yer~ical loca~ions along ~he guidetubes 36 and 42. Specific.111y ~ lock block 81 is 300sely rcccived in a cavity 82 reccssed in lhc firs~ slidc l-lock 65 an~l is gui~lcd for lr~nslalion~l roovemenl thcrein by a p~ir of t;~n~s 84A 3ncl 84B which conper~te wi~h the respectivc keyways 85A ~n~l 8513 formc~i in Ihc firs~ slide block 65. t~ first 1hrci~dcd draw ~o1~ 86 which is (lisposcd conccnlric;llly Or thc ;lr~icul~tion ~djusimenl ~xis 22 p~sses Ihrough ~ centr;ll aperture 87 ~ penctrates the lock block 81. A pair of qu~rlcr-cylindrical lock sur~;lccs 89 nnl~ 90 presente~l from thc lock block 81 arc disposcd for friction~lly locking cng;lgcmcnt wilh tl-c ~ui~le lubes 36 ~nd 42 respcctively. Tl)e firsl lhrradc(l ~raw boll ~fi tl-re~ably en~ages a cl~mp actu~tor 9lA which coopcr31es with :I p3ir of clamp b~rs 92 an~l 93 received wi1hin lhe housing 95 o~ lhe ~rm ~sseml~ly 14 ~o sccurc ~he posi~ion of the vertical supporl ;Isseml~ly l2A, ;In(l lhcrcrore thc posilion of lhc ar~icul;llion axis 2Q 22 in a rnanner lo he hcreinaflcr more flllly llescrihcLl.
A sccond dr;~w hol~ 96 is employcd lo sccurc lhc tr;ly ~ssembly I5 to the arm assembly 14 ~s will alSD l)C hcrein~rter morc ~ully described.
In ~dilion to lhc ho~lsin~ or l)o~ly 95 lhc arrn ;~ssem~)ly 14 includes a covcr 97 ~nd ~ cover pl;llc 98 ll~al are rcccivcd on opp~silc si(Jes of Ihe housing 95. The cl;lmp hars 92 an~l 93 ~re disl~ose~l in rccl~ng~ r recesses 100A and 100B providcd in lI:e l~ousilIg 9S ~s hcsl secn in I~IG. 3.
A plur;llily Or cl~mp ~clu;ltors 91 ~rc uli]ize~] in Ihc prescnt emhodiment. E;)ch cl~mp ;Icll~ator 91 h;ls ~ sul~sl~nti;slly T-sh~ped cross seclion wilh lhe cen~er 1 6103 ot c~ch l~ein~ lJispDse~l bel~vccn Ihe clamp l)~r~ 92 ~nd 93 and wilh lhe ~r~nsverse cross picce 104 Or e~ch ~bul~in,~ ~n appropri~lc rcaclion ~urf~ce on 1hc cl~mp b~rs 92 ~nLI 93. Cl.lmp DClu3tOrS ~ 2n~ 91B posi~ion the t~ansYcrse cross pieces 104 in abutmenl with the rci~ction surfaces which eonslitute the e~lges 105A and 105B of the ~espective clDmp bars 9~ ~nll 93.
Conversely, clamp ~cluatt)r 91C h~s ~t1e lr~nsverse cross piece ~04 disposed in ab~lmenl with Ihc rcaclion sllrfaces whicl) con~ilulc the opposile 1J~,CS 106A
2nd 1061~ of Ihe respcclivc cl~mp ~-~rs 92 anLI 93. Thc cenler le~ 103 o~ clamp actl~ator 91A conpcrD~ively cn~es Ihe first Ihre;~Lled ~Ir~w bol~ 86. The een~er leg ~03 of clamp ~c~ o. 9]~ cooperatiYcly cn~es lhc second Ihrca~le~l draw bo1t 96 ~nd the cen~er Ic~ ln3 oî ~he cl~mll ~c~l3tor 91C cooper~tively en~a~es Ihc 1hrc~1esJ exlensil)n ~0~ ot nn ~LIjuslmen~ conlrol knGb 108. Tl)e sh~nk 112 of thc a~ljuslmenl con~rol knoh 108 p;~sses ~hrough ~n ~pcrlure ~13 in thc ou~er surf~cc 1 t 1 of Ihe CDver 97 to en~3~e a gener~lly recs~ngular lhrust force dislribution w~shcr 114 which is s~ porteLI 3cross 3~ Ic3s~ ~he rccesseLI shclves 1l5A an(l 115B in the housin~ 95. A be~rin~ w~sher 110 may bc intcrposed bctween ~hc sh~nk 112 of Ihc adjustmen~ conlrol knob ~08 3nd the thrust force distribu~ion w3sher 114 lO reduce ~he rric~ion;ll forces Ihercbetween.
Bcctlusc Ihe Ihrllsl force slis~ril)ulion w;lsher 114 abuls ~he suppor~ing shelves ~15 recc~scLI into Ihc h(~llsin~ 95 rolnlion nt II)c ~LIjuslmcnl conlrol knob 108 in a ti~lltenin~ direc~ion ~vill ~Irivc Ihe transverse cross piece 104 on cl~mp ~clu~or 91C inlo en~n~emenl wilh lhe rcnclion surfaces derined by Ihe cdges 106A an(J 106~ on Ihe rcspeclive cl3mp h;lrs 92 3nd 93 thus displ~cin~ Ihe cl3mpb~rs ~n~l forcin~ IhC re3ctinn surf;lccs dcfinc~ y Ihc e~l~cs 105A ~ntJ 105B of lhc respective cl3mp h3rs 92 ~n(l 93 ~3inst ~lle Ir~nsvcrsc cross piece 104 on cnch of the cl~mp ~clu3lnrs 91A l~n~ 9113 whicl1 in turn lon~;~udin~lly transl3te the respcctive drnw hnlls 86 an(l 96 low;lr~ c covcr 97.
Thc ~rm asscml)ly 14 Il;~s ~ p~ir of br;~ke p3~1s 116 3n~ 117 tJisposeLI
belween Ihe housin~ 95 ~n~ lc secon~l sli~c bloc~ 66. Thc secon~l br3ke pa~l 117 h3s 3 plur;llily of 2perlures 118 wllich 3rc ali~n;lble wilh ~n~l receive Ihe posts 119 forme~l on t1lc secon(l sli~Je hlock 66 ~o prevenl rcl~live ro~alion therebetween. Thc f;rsl hrtlke p3LI 116 h;ls ~ pl~lr~lity of 3perlures 120 whichcng~ge the posts 121 (l~lG. 4) cxtcn~in~ outw~r~lly from ~he housing g5 ~3 mounlthc first br3ke p;l~l 116 non-rot~t~biy on Ihc housin~ or body ponion 95 ~f thc arm ~ssembly ~4. Wl~en Ihe asljus~menl conlrol knob 108 is ro~cd in she ti~htcnin~ direclion, Ihe ~Ir.~w boll 86 will CallSC Ihc lock block 81 ~nd slide block 66 to eng~e l1le guide lul)cs 36 an(l 42 wilh surficicnl rriclional conlacl lo sccure the vcr~ic~l adjuslment assemhly fi4 ~o ~he ~uide tubes 36 and 42, thercby directly cst~blishing the vcrtical position o~ the ~rlicul;ltion .~ljuslrnent nxis 22, and indircctly ~hc vertic;ll heigh~ of the Ir~y ~ssemhly 15. The resultan~ lrans]ation of the ~Iraw hDlt 8fi will also c;~usc the hr~c p~l~s ~ ~6 antl ~17 io be sim~ neously urged into fric~ion;ll eng:lgement, lllerel-y es~al~ llina~ lhe ;In~ular, or ~r~icll1aliDn, z~

position of Ihe nrm asseml~ly 14 rel~tive lo ll-e supporl Dsscmbly 22A. Tt-e angul~r positk)n r)t Ihc arm asseml71y 14 can be vcr~ic~lly oricnlcd as rcpresentcd in FlG. 6 or skewe(l .~s dcr~ieled in l;IG. 7.
A pair of brakc pads 122 ~nd 123 ~rc disposecl bctween tllc housing 95 ~f lhe nrm assembly ~4 ~nd Dn en~l surf~ce ~24 on ~he Ir~y assembly 15. Thc second bra~e pa(l 123 has a plurality ot npcrtures 126 which mount lhc p~d 123 on posts 127 formcd on Ihc surf~ce 124 lo limil Ihc rcla~ive rolation between thc second brake pad 123 ~nd llle Iray housin~ 15. The first brakc pad 122 is mounted on sim;l;lr pos~s 12R (I;IG 4) rormed on thc housing 95 and which are rcccivcd ~hrough ;lpertures ~2~ in ll)e firsl br~kc p~d 122 to limit the rclativc rotati~n between Ihc first hrake pad 122 ~nd thc l~ousins 95. ~s such when Ihe adjustment conlrol l;noh 1n8 is ro~ cd in Zl ti~hlcnin direclion Ihe secon~l dr~w bol~ 96 scrves lo urge the hr~kc p;lds 122 and 123 into friclion~l eng~gemcnt thereby establishing lhe ~ngl~ r position of the tray 15 about the pivot ~xis 24~nd relalive to ~he arm nsscml71y 14. Thc ~r;ly asscmbly ]5 can thereby he tille~l independently ot the angul;lr ~rlicul;llion of the ;lrm ~ssembly 14 rel~live ~o lhe support assemhly 12~.
In summnry ~hc liltin~ disposiliorl of Ihe tr~y ~ssembly IS about the pivol~l ~xis 24 and the articulation Or Ihe ;Irm Dssembly 14 al70ul the ~rliculaling axis 22 are indcpcndcnlly achicv;lhle. Tl-c verlic;ll Ddjlls~ment ot the tray asscmbly 15 Dccoml~lishcd l-y Ihc disr)osilion or Ihc adjustmcnl asscmbly 64 ~long ~he guide tubes 36 and 42 is also indel~en(lenl or Ihe olllcr a~justmcnts cven thou~h all ~djus~mcnls are secure(J 17y locliing mecllanisms ~hat c~n be aclu~lcd by a single adjuslmcnl conlrol knoh 1û8.
As bcs~ seen in I~IG. 4 thc housing 95 has a firsl pos~ ~30 cxlcnding latcrDlly Dl~lwar~Jly Ihcrefrom in thc direclion of ~I~c sccond sli~le block 66 The flrs~ pos~ 130 tils wilhin ;~n openin~ 131 localc~J suJ~stanlially centrDlly of lhc sccond sli(le block 66. llle ~irsl post ~30 h;ls a longitudinal passa~e 13~
extendin~ there111rough an~l ~hrou~h which ~he tirsl ~Iraw l~olt 8G slidal~ly passes prior ~o bcing thre~(led in~o thc cl~mr~ aclll~or 91/~. ~ secon~ pO5~ ~34 also ex~encls la~erally ol~w;lr~lly frDm ~he hnllsin~ 95 ror ;nser~ion into ~ bore ~35 forme~l in lhe facc 124 o~ ~he ~r~y ;~ssemhly 1~. Tlle second post 134 h~s a longituulin~l p~ssil~e 13h cxlen~Jin~ Inn~ 3inlll1y ~hcre~hroush lo rcceive lhe 9$~

second drnw bolt 96 and ~hereby provide ro~ary supporl for an~l a mcans by which ~o cen~er thc Iray assemhly 15 ~nd Ihe secnnd draw l~oli 96 wilh respcct to the arm ~sscmhly 14. To reduce the concentralion of pressure applicsl hy the draw boll 96 upon Ihe ~r~mc 141 of ~he lr~y ~sscmhly 15 one m~y in~erpose onc or rnore washcrs 137 and 138 bclwcen Ihc hen~ 157 of ~he draw bDlt 9G and lhe reaclion surface 166 presented by Ihe recess 144 in lhc tr~y fr~me 141.

First VDrintiOn An adjllslment mecl1~nism 10~ which consliSutcs a v~ri~tion o~
mech~nism 1OA is shown in l:lGS. ~ 9A ~nd 9B. Thc mcchanism lOo incorporatcs ~he s;lmc mountin~ h~r 11 ~nd ver~ic21 supporl assembly 12A as shown an~l llcscril~c(l in conjunclinn wilh ~ ;S. ~-7. ~n .Id(lilion ~he s2me br~ke pad struc~lre is utilized. Ilowever Ihe ~djllslin~ mcchanism 10n is dirferent from the mechanism ~0~ in lll;ll ~ dolll~le endcd Icver 140 (FI~. 8) is operativcly posilioned in ~he ~ray asscml~ly 15. In facl ~he Icver 140 is localcd bc~ween the tray fr;lme 141 nnd Ihc Ir~y surr;lcc mcml>cr 142. So localcd Ihc lever 140 cooper~lively en~es n levcr rele;lsc ~cluntor 143 which is disposed for swingingrnovement in a recess 144 provitlccl in lhe ~rny fr~me 141.
The acl~lalor 143 h2s d~ lpwar(Jly exlen~lin~ Ic~s 145A ~nd 145B
located in sp~ce(l ~nd c~fcclively oppnscd rel;l~ioIl wi~h a sin61e upwardly ex~endin~ le~ 14fi. The lever 140 is received he~wcen Ille opposed le~s 145 and 146. Thc ~Ippcr cxlen~ Or lhc le~ 145 ;m(l 14fi arc disposcd in proximily to ~heunder surf~ce 147 of Ihc tray surr;lcc meml)er 142 an~ cooper~tc IO form a channel 148 which prevcnls Ihe Icvcr 140 from bein~ cxtricatcd unless lhc tray surface mcmbcr 142 i5 remnvccl from lhc trny rr;lmc 141. The Icver 140 has n pair of fin~er conlrnl hnndlcs 149 and 150 securl:(l to ll1c respec~ive end por~ions 152 and 153. Tl)e finger conlrol h~ndlcs 149 ~nd tS0 ~re dispQse~l benealh lhe tray surfacc memher 142 oul Df view Or the t~per;~tor but wilhin easy rc;~cl1 ot ~he opcrator s fingers.
As bcsl sccn in ~IGS. 9A ;Ind sn, Ihe ac~ or 143 has a c;lm surface 154 which is disposed in opposilion to Ihc hore 135 whici~ passes ~hrough Ihc cnd surface 124 of Ihc tr~y fr~rne 141. Thc c~m surFlcc 154 prcfcrul~ly h~s a generally cylindric;ll apl7e~rin~ cross section which ~l~Ul5 ;I rc~clion pl~le 155.

2~

The he~d J57 of ~hc seCon~ slraw hol~ 96 i5 also disposcd in opposilion lo the cam surt~ce 1S4 ;In~l ~hc hc~d 157 i5 sep~ralc~l from lhe c~m surf~cc ~54 by theTcaction p~ e 155.
A p~ir nf be~ring sur~aces 158A and 158B ~rc forrned on thc actuator 143 antl arc dispnsed opera~ively lO cngi~ge rcspec~ive receivin~ journ~ls IS9A
and ~59B which are formcd on the w~ll mcmbcrs 160~ ~nd 160B respcctively, prcsen~cd by Ihe ~r~y frnme 141 to posilion thc reccivin6 journ~ls 159 wilhin ~he rccess 144. As lhe lever 140 is opcr~lcd l-y one tinger con~rol h~n~llc i49 or lhe other 150 the ;~clu~lor 143 will swing ahou~ one or the othcr of lhe receiving journ~ls 159A or 159~ tl1e resul~s ot whicll ;Ire more rully hercinarlcr described.
A spring 163 all~l spring seals lfi4 and lf)5 are supporled on the second dr3w boll 9fi and are disposed he~wecn thc hc~d 157 o~ lhc druw l-olt 96 ansl a reaction surr;lce lh6 provide~l in ~he Ir~y fr;lmc 141. In ract thc hcad 157 m~y be rcceive(l wilhin lI~c cllppe(l reccss 167 in spring se~t 164. An opening 16R penetr~les thc rc~ction surr~cc 166 to rcgister with ~he pass~ge 136 in thc posl 134 whicl) is rcceived witllin ~hc llore 135. Thc sccond dr~w bolt 96 ~hus passes tllrough Ihe opening 168 ~n(l the p~ss~ge 13G oper~tively lo cn~ge the cl~mp actuator 9113.
As is app;lrcnt hy comparing ~hc disposi~ion of ~he ~ctuator 143 and lhe compnnents ass()ci;l~c(l therewitl1 a~ reprcscnlcL5 in l:IG. 9~ with ~he disposition o~ ll)c actu;~lor 143 ;ln~l Ihe cnmpnncnts ~ssnciated tl1ercwith as depicle~l in T~IG. sn, s~vinging movemcn~ Or ll-e ~ctualor 143 ~boul eilher receiving jo~lrnal 159~ nr 159n will zlpl31y r)re.~urc on lhc sr)ring sc;~t 164,through rcaetion pl;llc ISS, lO compress the sprin~, 163 bclwecn Ihc ~lu~or 143 anll thc rc~clion sllrrace 16fi. Th;.t snme pressurc ~pplie~l to the reilcli~n platc 155 i5 also av~ b1c lo nct ~Ipon Ihe he~l IS7 to ~s~urc t51~l the secon~l ~Ir~w bolt 96 may be displ;lcc~ rDugll ~ ~is~3nce l'A", ;15 sho~vn in I~IG. 9I3. Tlle swingin~
movemenl which achicvcs the aforc~ai~l resul~s is clcp;ctecl as occurring aboul receivin~ journ~i 159A, ~n~l lhrnu~h an anglc a. The res~ ing Iransl~to~y displ~cement of thc secnn(l draw bol~ 96 will looscn ~I-e ~ric~ion~l cng:l~,cment between the br.lkc ~ ls 122 ~n~l 123 ~nll permit ~ ing ;I(ljus~ment of Ihe tray assemhly 15. Thc compressinn Or Ihe spring lfi3 will ~Iso serve 1D relurn the Z~ 9~ ?

- 14~

actuntor 143 lo the ncl)lrill positit)n ~Icpicle~l in ~IG. 9~ whcn ll~c operaSorrclenses the fin~er press~lrc aprlicd lo eilher conlrol h~ndle 149 or 150.
ln ~rùcr l~ DchieYe lhe foregoing rcsull ~hc cl~mp aclu310r 91C, ~nd Ihe ~ssoci~ted ~us~menl conlrsl l;nol) 108 u~ilize~l in ~ljusling mcchanism 1OA,are replaced by ;I rockcr plnte 170 (FIG. 8) which rests trans~tersely ;Icross Ihe base w~ll 171 of lhe reccsses 100~ ~n~l lOOn in the ho~lsing g5. In facl the diviLlcr wnll 172 hc~ween lhe recesscs 1OOJ~ nn~l l0013 is relicvcd to Drcommod~lc pl~cement of lhe rocl;cr plnle 170 such ~hnt ~ fulcrum etlge 173 presen~e~l fromthe rocker pl;l~e 170 will cng~c ~he ed~es 10fiA anll lOGB on ~he respective clamp b~rs 92 ~nd 93 in order Ih;ll Ihe clnmp b;lrs 92 ~n(l 93 m~y rock. The clnmp b~rs 92 ~n~l 93 ~rc ~Ir~e(l inlo DbulmenI willl Ihe fulcrum c(lgc 173 on ~hc rocker pl~le 170 hy Illc rorce in Ihe sprin~ 163 ~c~ing Ihrough ~he second dr~w boll 96 ~nd Ihe cl;lmp ~ct~l~tor 91~t conjoined thereto. The first llr~w bolt 86~n~l cl~rnp ~ctu;~tor 91A operalively connected II-ereto ~rc ~Iso subjecle-l ~o lhe force Or ~he sprin~ 163 such Ihn~ Ihc sprin~ lfi3 effccIs fric~ionnl cn~;lgemenlbehveen II)e brnke p~ds 116 nnd 117 ~nd ulr;ves the lock block 81 inlo clnmping eng~emenl with ~he gUilJc lubes 36 ~n~ 42 As previously cxplnine(l con~rol of Ihe brnke pnds 116 and 117 permits seleclive posilioning Or Ihe Ir;ly nsseml)ly 15 ~boul ~he ~rliculnlion axis 22~ nncl control of Illc lock l~lock ~1 31so permils selcclin~ the verticnl posilion o~
the ~r~y ~sseml)ly 1S. TllIls Ihroll~h m~ni~ inn of Ihc Icvcr ~40 ~lle oper~lor c~n in(iividu~lly adjust ~ny Or lhe position controls or sino~ls~ncously a~ust any combinalion Ihereof. ~I shoukl be nolcLI Ih~l wilhoul ~he use of ~n a~ljus~ing control knob 108 ~he covcr 97~ mny hnve a conlinuous uninterru~lcd ~u~er surface 111,~.
As dcpictetl a l~ter~lly elong~teLI opening 161 may pel1~Sr~le the actuator 143 in registry with a borc 162 (hrougll lhe rc;lction platc 155. Theses~penings 161 ;In~l 162 permit one to ~ccess the he~Ll 1571 which c~n accDmmo~Jatc an allen wrench to adjIlsl ~he inili;ll Iension ot ~he spring ~63 in order to ~ssure that selcclive aclualion ~f the levcr 140 will rele~se ;Incl ~ighten the ~cljuslin~ mcchanism ln" ~s ~lesirc(l n 9~"?
- ~5-Scct)nd Ynri~t;on The varinn~ adjlls~ing mechani~1n 10c shown in ~IG. I0 utilizes the same coml)onents ror eftecling vcrlic;~ (ljns~menl or thc arlicul~tion .Lxis 22 Ihe same Componenls for eontrolling tlle ~ngul;lr posilionin~ of the arm assembly 14aboul the ~rticul;~lion ~tis 22 and for eon~rollin~ the heigllt of the articulation axis 22 ~s well as the s:lme componcnls ror conlrollin~ thc an~ulilr position of lhe tray assemhly 15 about Ihc pivot axis 24 ns were previously dcscribed hercin Wilrespeel lo ~he exemplary eml)odimen~ 1OA tlcpiclctJ ;~nd ~JescribetJ in ennjune~ion with ~JGS. 3 thrnllgh 7. I-lowever in the adjustin~ mechanism 30C ~lepictetl in ~ig. 10 thc oper~tor is r~rovidet3 wilh sep~rale conlrols includin~ one control for the atJjus~men~ nrountl ~he pivol axis 24 antJ a sccond control for the vcrlica pDsitionin~ of and nn~ular posilinnin~ ~hnul thc nrlicul~ion axis 22.
The mcch~nism by whicll lo accomplish adjus~mcnls rel~tive to lhe articulation ~tis 22 includcs a firsl tJrnw boll 86 ~hat is direc~ed throug~l~ n thrust force distrihullt3n w;lsher ~14A opern~ively In en~n~e nn atJjustment control krlob 108A. The shank 112A on knol) It)8A exlcnds lhro~ n openin~ 113A in the ouler sur~ce llln Or lhc covcr 97" lo inleracl wilh ~he thrus~ force ~lislribu~ion washer 114A. A l)enrin~ washer 110A m;ly be interr~osed belween Ihe shank 112A tlnd the thrus~ wnsher tt4~ ror lhe same purposcs previously discussed herein reln~ive to mechanism 10,. Rot~tion of the ntJjustmcnt control knob 108A
provitles ~lIe operalor wilh the nclu;lling conlrol neces~ary nol only for atljusling the arm asseml)ly 14 abo~ll lhe arlicul~tion axis 22 bul also for tJireclly selecling the desired height of the nrticlll~tin~ nxis 22 which indirectly determines ~l~ehcight ~f the tray ~sseml31y I5.
Further with respecl to the v~ri~nt mech~nism lc. the heatJ I57A
~which has ~ poiygon;ll oulcr edge surr;~ce) on tl)e secontJ ~Iraw l)olt 96 is cnplured in n hex washer phl~c 17~ Ih~ is slJppt)rletJ in lhe recess ~44 providcd in tray trame 141. The hex washer plate 17~ has reaction t~bs 180 which engage the Iray irame 141 in such ;I w.ly :Is ~o prcvcn~ it :~n~l lhus Ihe secon~l dr~w bolt 96 from rot;lling. The sec~nd dr;~w l)~ll 96 ~Iso p lSSrS shrQu~h ~hc cs)mpQnen~s recelve(l wi~hin Ihe l)ore 135 in Ihe Ir;ly ;!sseml)ly t~ ~s prcviously ~iiscusseù wi~h respecl ~o FIGS. 3-7 ~n~l inlo the hnusin~ 9S opcril~ively ~o en~Be ~he control krob 10813. lhe sh;lnk 1]2B on knoh lO~B extcn(ls ~hrough t1-e opcnillg 113B in Z~ 9~?~

the outer surface 111 ll Or the cover 9711 to interact wi~h the tllrust force distrihu~inn washer 114B A bearing washer 11 OB may als() be interposed between the shank 112n ;In(l lhe thrust wasller 114B for the snme purposes prev;ously tliseussed herein. J~o~alion ~f the il~3jus~ment eontrol l;nob 108B
provides the operator wilh the aeluating eontrol necessary for adjus~ing the tray assemhly ~5 ~bout the pivol ~xis 24 Third Vnriation The variation re~resenle~l by ~he adjus~ing meehanism 1nV sho vn in F~G ~1 providcs a sin~le alljus~ment control knob 308 for ac~u~ing the locking meehanism hy wllicl1 to permit seleelion o~ the vertieal disposilion of the artieulation axis 22 an~J artieulali~n of the arm assembly 14 thereabout as Jescribe~l in eonjunclion wilh I:lG 10 Alll~ou~h tha~ lJescription is not repea~ed ~t this location the struelure whicll permits the draw boll 86 to inter;lcl wi~h ~he a~justment eon~rol knoh 10~ ~hrough the sin~le npening 113 in the outer surface l~c of lhc eover 97e is i(lenlifie~ by Ihe s~me numbers in F~C 11 as are usell in eonjunclion with the descrip~ion for the same struclure as that slruclure was describe~l relative to the varia~ion shown an~l described in eonjunc~ion wilh FIG
10 set forth previously herein A friclion resistant arran~emenl is employe~l to con~rol the angular posilionin~ or Ihc tray ;~ssembly 15 ~bout the pivot axi5 24 The friction resistant a(Jjustmenl r()r tilting the tray asseml)ly 15 employs a pair of brake p;l~35 122 an~
I23 as shown an(l ~lescribe~ wilh respecl lo FIGS 3 anll 4 which arc main~ained in engagement hy a spring 185 which surroun~Js the secon~ draw ~oll 96 and is confineLI hetween the housing 95 an~l a hex washer pl;lte ~6 Tlle ~Iraw boll 96 lhrea(lably enga~es a nut 187 whieh is eap~ure~l by and therefore held non-rotalable rela~ive to Ihe hex washer pla~e 186 which in turn is hekl non-rosatable relative to the housin~ 95 hy ils engagement with the divi~ler wall 172 in the housing 95~ A washer 1~8 may be employe(l no~ only to re~luce the ~orce concentra~ion on the housin~ 9S l>u~ ;~150 to prolec~ the hollsin~ 9S rrom possible ~Jegra~la~ion hy en~a~emcnl he~ween lhe spriny 185 an~3 ~he m;lterial from whichthe housing 95 migh~ he ma~Je Likewise a hearing washer 189 ;In~l a force dis~ribution washer 190 may l-e receive~l in the recess 144 lO re~ ce ~he force Conccn~ralion be~ween ~hc round heall 157 of lhc draw bol~ 96 an~l the rcac~ion surfacc 166 at one en~l ot Ihe recess 144 in lhe ~ray rrame 141. Thus tlle friclion forces in Ihe brakc pa~s 122 ~n(~ 123 which rnay hc i~lentical to ~hose ~lepicted in FlGS. 3 and 4 will delermine ~he angul~r position or the Sray ~ssembly 15 about lhe pivot ~xis 24. The ;Imount o~ friclinn rorce ;tvaililble is determincd by lhc forcc applied by spring IB5 wl~ich of coursc is controllc~l by the tigh~ncss of Ihe nut 187 on the ~Iraw bolt 96. As such the spring force c~n bc ch~n~ed by simply ghlenin~ or loosenin~ tl~e llraw bolt ~6 inlo Ihe cal ~ured nul 187.

I;ollrth Vnri:ltion Thc vari;llion eml)otlie~l in a(ljllslin~ mechanism 10~ reprcsen~cd in FJC. 12 uses ~hc same hrakin~ nrrnngemen~ ~ lhe lower en~l of the arm assembly 14 ~s previously ~lescril)ed hercin wilh rcspec~ FIGS. 3 8 ~nd 10 to rcleasc an~l ho!~J ar~iculalion and ~17c verlical ~lisposi~ion ot thc arm ~ssernl>ly 14.
However thc hraking ~rr;~n~emcn; is ac~usl(e(l hy ~hc s~me rocking arrangemcnl of the clamp bars 92 an~ 93 employe~ ;n Yari~ion 10u shown ~nd described in rela~ion ~o l~IG. 8. The primary dirfcrcncc is tha~ in mechanism 10~ actua~ion is effec~cd by ~ sin~le adjllslmcnt con~rol ~nol) 108 in a manncr similar lo that by which ac~ua~ion is ctfeclc(l wilh the atljusling conlrol knol) 108B cmployesl wi~h varia~ion lC- as shown and descril-e(l in conjllnction with FlG. 10. Thus while 2t~ the clam~ hars 92 an(l 9~ ~nd roc~;er l)la~c t7() arc idcnlic;ll lo ~he conslruclion ot mechanism 10" -- as represenlc~l and descril)etl in conjunclion wilh ~C;. 8 --rockin~ thc clamp hars 92 ~nd 93 to ;Iclu:l~e thc hrakc pads 116 an(l 117 is e~ecled l)y manip~ ion o~ e sin~le aclua~;ng consrol knob 108 by applying or re~cas;n~ prcssurc a~ainst the cl~mp b~rs 92 and 93 wi~h lhe tl)mst force dislribution w~sher 114 Actuatin~ conlrol ID selcc~ lhc til~ctl ~lisposilion Df ~hc ~r~y ~ssem~ly 15 aboul Ihe piVOl ~xis 24 ~l~ilizes ~he 3rran~emen~ tha~ is shown an(l (lescribed wi~h respccl lo mecll~nism 10C (3cpic~e(1 in l:lC. 10. That is lhe llca(l l57A
~which has a poly6on.l1 ou~cr ed~e sllrr~ce) on Ihc sccond draw b~l~ 96 is 3~ caplurc(l in a hex w~shcr plalc 179 llla~ is su~pnrled in lhe recess 144 provided in tray frame 141. The hcx w~shcr pl~le 179 has reaction tabs 180 which cnga~e the ~ray trame 141 ;n such a w;~y ~s lo prevenl i~ ansl ~hll5 the second drnw bol~

96, from rotatin~. The sccon~l drnw bol~ 96 ~lso p~sscs throu~h the components received wilhin Ihe bore 135 in thc Iray ;Isscmhiy 15, as previously l3iscusse~1 wi~h respec~ to FICS. 3-7, an~l into Ihc housin~, 95 opcratively ~o cngage the control knob 108. The shank ~12 on knoh 108 cxlcn(ls through lhe opening 113 in the outer surface 111" of lhe covcr 97~, to interact wilh Ihe Ihrust forcc ~lislribu~ion washer 114. ~ hearin~ wasl)er 110 may nlso he interposell bctw~cn Ihe shank 112 and the ~hl-U5l washer 114 for Ihe same purposes previously discussed herein.
To summnrize, lonsenin~ she a~ljustmcn~ control knob 10813 directly relcases the force which ~Irivcs shc hrake p;ltls 122 an(l 123 (shown an~l Jcscribcd in conjunc~ion wilh lhe nrrnn~cmenl (Jepicle~l in l~lGS. 3-5) to permi~ silIing adjuslmen~ of thc tray assembly 15. Tllis samc moverncnt of lhe linob 108, ho~4ever, ;llso looscns not ollly Ihe hr.lkc pnLls 11fi anul 117 but also the lock block 81 in the verlical support assembly 12A by lhe rockin~, nction of Ihe elamp bars 92 nn~l ~3. As dcscrihe~i in conjunclion willl mech;mism lOn ~lepicled in FlG. 8, thc renc~ion of Ille clnmp l~ars 92 nn~l 93 n~;linst the rocker plate 170 is ~frcc~ive selcctivcly so apply, nn~l wi~h~lrnw, the force required to draw Ihc brake pntls 116 nn~l 117 into friclional cn~n~,ement an~l simultaneously forcc the lock block 81 into en~n~cmcnt wi~h lhe ~ui~Je luhes 3fi) nn(l 42. Thus, noS only is the tille~ position ot the Irny nssemhly 15 n~ljust;lhlc hy manipulation of a single~jus~menl control knol~ 108 in Illc v;lrianl mcch;lnism 101! hul also the arliculntion, anll hci~llt, of she arm ;lssemhly 14.

Sccond E:ml~odimcnt In the emhotlimcnt reprcscnte~l hy mcch;lnism 10" depicted in FIG. 13 Ihc vcrlic~l position o~ tllc Ir;ly ;Issembly 15 provislc~l by ~he support ~ssembly 12n is ~ixe(l. I-lowever, Ihe mecllanism 10~, provi~cs for ~ljustment of lhe lray assembly 15 abo~ he pivot ;Ixis 24, ;I(ljustmcnl of ~he ~rm assembly 14 abou~ lhe axis of ar~icul~tion 22 antl rota~ion~l movemenI Or ~he support ~ss~mbly 12D
about ~he vertic~lly oriente(l rot~tional Dxis 2~. ~djus~menl ~bous lhc rolary a~is 21 is accomplishe~l in a munRer similur IO Ihal provi~le(l in cach of the foregoin~
~arialions. Thal is, reccsses 60 im~3 61, in thc mounlin~ b~r 11, ~n;l a convenlional ball s~clen~ ~ssemhly 57, prcsenlc(l rrom ~he vcrsic~l support assembly 12n~ cooperatively inter;lcl. The sIlpporl usseml~ly 12~ h~s a st;lnchion - 19. 2~ 3rj~

193 lhat hollses ~hc h~ll sJe~en~ mechanisrn 57 ~n~l Ihe suppor~ assemhly 12n isrot~t~bly mnuntc~l on thc mounling bar 11 by a post 194 hnving ~ I;nurled en~l 195 that may be press fil into Ihe opening 33 in Ihe llist;~l cnd p~rlion 20 of the mounlin~ bar 11. The knurling preclu(les rotalion Or tile pO51 194 rel;Jtive to ~he moun~ing bar 11. A lhreadel3 fas~cner 196 c~lends upwardly ~hrough the pO5~
194 and threa(l~hly en~cs the s~ancllion 193 A thrust washer 54 is disposed between ~he basc 197 of ~he stanchion 193 and the upwardly facing surf~ce 32 of the mounling bar 11.
An~ular cnn~rol of ~he ~rm assembly 14 ahout Ihe arlicula~;on axis 22 is controlled by a sprin~-bi~selJ friction arrangement generally cornparable ~o tha~
shown for Ihc pivo~ axis 24 contr~l in mechanism 1OD shown an(l ~lescribed in conjunc~ion in conjunc~ion with l;IG I l Tha~ is the t~raw bolt 86 p~s~es throu~h a decorative covcr 197 ~ p;lir Or lhrust w3shers 19X 2nd 199 ~nll an opening 200which penetr~tes the stanchion 193 The tlr~w boll 86 then passes through Ihe brake p~lJs 116 antl 1~7. Brake pad 11fi is non-rot~tably carried on ~he housing95 in lhe same m;lnner shown ~n~l tlescril~cd in conjunc~ion with FIGS 3 an~l 4 Pos~s 119 ~re presente~l from ~he stanchion t93 in the same manner ;IS the posts119 are prescntc~ from the slide block 66 shown an(l llescribed with respect to those fi~urcs sn ~ t l-rakc p3d 117 m;ly be non-ro~at3bly carried on stanchion 193.
Afler thc draw bol~ 8fi p~sses through housing 95 it is surrnun~3ed by a sprin~ 201 wllich i5 rel~inc(l he~wcen ;I w.~hcr 202 th~t enga~es the housing 95and the hex w~sher pla~e 203 which ~Iso en~ages Ihe housing 95 lhe thrust washcr 202 is llispose~J bc~ween the en~J of spring 185 an~3 the ba~c wall 171 (FlG. 4) in thc housing 9S The hex w~sher plate 203 spans both ~nll is ret~ined in thc reccsses 100 in housing 95 in spnccll relation outwardly from the b~s~ wall 171. A hcx nut 204 is c~p~urel~ by ~he hex washer pl~te 203 such that lhe nut 204 is also non-ro~t~ble with rcspec~ to the hnusing ~5 lhe îriction~l force presentto de~ermine ~he ~ngular position o~ the arm assembly 14 is ~stabli~he(J by the ~igh~ness of Ihe ~lraw holt f~6 This force may of course be ~ljustecl by ti~,htenin~, the dr;lw t~nl( R() in~ hc c~plllre~l nul 204.
Thc an~ul~r po.sition or thc tray ~755erl7bly abou~ the pivo~ ~;is 24 m;ly be est;~ heLl an~l provi~lc~l by a s~ruc~lre i~lcn~ic.ll to ~h;lt preYiou!,ly llescribe~l I$J~

hercin Ihe v~rii~nl mcch~nism ID~ shown in l:lG. Il. It is believcd that a repctilion of Ih~ descriplion is not necessnry.

~arinliDns ot lhc Sccond E:ml)r~dimcnt llle vari~tion cmbodie~l in the ~djustin~ mech~nism 10a shown ;n l:IG. 14 utilizcs ;I vcrtic;ll supporl 12~ wl~icl~ m~y l-c i~3cntic31 10 th~t incorpornted in mcch~nism ~0~ reprcsented in FIG. ~3 an~ Ihc angul~r conlrols rclativc to the ~lisposilion Or lhc ~rm nssembly 14 ;Ibout thc articul~tion axis 22 and thc trny assembly 15 ~I OUI the pivot axis 24 m~y be i~lcntic~l lo 1l~DSC usc~
in conjunclion with thc mech;~rlism var;ation IO~ disclose~l in FIG. 12.
The Yariations ïOll and 1UJ shown in ~IGS. I5 and 16 respcc)ively both use vcrtical s~ port ~sseml)lies 121~ cnlic;ll to those shown in l;IG. 13.
The FJG. I5 v~rialion 10ll u~ilizes in ~he an~ular controls for thc ~r~icul~tion asis 22 ~nd thc piv~t axis 24 struc~ure tha~ is i~lentic~l to th;~t described rel~tivc to varia~ion 10C shown in l:IG. lO. A~juslmen~ mech~nism v~ria~ion ~0J dcpicted in FIG. 16 wllilc u~ilizing ~ vcrlical supporl ~sscmbly 12~ clescribcd in conjunction with v~riation 10~. sl~own in l:IG. 13 ;~lso utilizes ~Inlc~urc ~ t is iùcntical to that dcscribe~l with respecl ~o ~:lG. 3 to cr~ect tl~c an~ular conlrols about thc articul~lion axis 22 3n~1 thc pivot axis 24.

Sllmm~tion One skillc~ in tl~e ar~ will npr)reciale ~ is point th;lt m~ny vari~ions not explicitly (Icscribe(l are possible. ~or cxample the single lever control 140 ~lescribe~l ror Ille structural v~ri~lion 10~ depictc~l in l~lC. ~ coukl be use~ with Ihe rixcd vertic.ll support assembly 12~1 describe~l for Ille structur~l v~ri~tion IOI shown in FIG. ~3.
As was previously mentioncsl thc mounlin~ r l1 may be sccurcd ~o thc unllersi~le 17 of thc chilir seating frame 18 for cither ri~ht h~n~ or lef~ hand usage of shc chair. ~nasmoch as ~lle tray surfacc member 142 has ~ gcnerally arcl~ate recess 205 (i:lGS. 2 ~n~l ~) alon~ ~l Icast one clJge thercof which provides a Wwr;lp arol~n~l" arfecl for lhe complller operR~or, cll~ngin~ from ri~ht to 3~ left han~i usage will rcqllirc. Ih~t the lray surr;lc~ member 142 bc remoYe(l from the tray frame 141 ancl rol~e~ horizon~;llly Ihrn-l~h 1~0 ~legrees to locs~te lhe 2~'~J~
-2~ -arcuale reccss 205 propcrly whcn ~he a(ljlls~mcnl mcch;ln;sm 10 is cllnn~c~l from one to ~hc o~her 5i~1c of lhc chair. This rcsull can bc rcntJily accomplishe~l by securing thc tr~y surfacc member 142 lo lhe tray ~rame 141 by four fas~cncrs 206in thc nature of screws which ex~cntl lhrou611 ~I)e hnles 207~ 207B 207C an(l 207D in thc trny frame 141 operalively ~o en~n~e lhe un~lcr surfncc t47 on thc tr~y surface mcml)cr 142.
As shoukl now bc apparent lhe presen~ inven~ion not only tcachcs that ~n ~tljus~ing mechnnism cml-o(lyin~ ~he concep~s of tllc prcscn~ învcnlion cnn bc rca~lily supplie~l for use in Conjunclion with n chnir-mountc~l computcr input device but also Ihnt ~he other objecls Or ~hc invention c~n likewise bc ascomplishe~l.

Claims (26)

1. An adjusting assembly for mounting a supporting tray assembly to a chair, said adjusting assembly comprising:
a substantially horizontally disposed mounting bar having distal and proximal end portions;
said proximal end portion supported from a chair;
a substantially vertically disposed support assembly mounted from the distal end portion of said mounting bar;
an arm assembly having first and second end portions;
the first end portion of said arm assembly supported for articulation from said support assembly;
a tray assembly pivotally supported form the second end portion of said arm assembly.

2. An adjusting assembly, as set forth in claim 1, wherein:
said arm assembly is articulated with respect to said support assembly about an articulating axis that is disposed substantially horizontally; and means are provided selectively to establish the distance between said mounting bar and said articulating axis.

3. An adjusting assembly, as set forth in claim 2, wherein:
said tray assembly is pivotal with respect to said arm assembly about a pivotal axis that is disposed substantially horizontally; and locking means are provided to secure the selected pivotal position of said tray assembly with respect to said arm assembly, to secure the selected articulation of said arm assembly with respect to said support assembly and to establish the selected distance between said mounting bar and said articulating axis.

4. An adjusting assembly, as set forth in claim 3, wherein:
said arm assembly has a housing which defines said first and second end portions of said arm assembly;

a friction means is associated with each said first and second end portions defined by said housing;
a portion of said support assembly is embraced between a lock block and a slide block;
said slide block having a friction means disposed in opposition to said friction means associated with the first end portion of said housing;
said tray assembly presenting a friction means disposed in opposition to said friction means associated with the second end portion of said housing.

5. An adjusting assembly, as set forth in claim 4, wherein said locking means further comprises:
clamp bar means supported from said housing;
clamp actuator means engaging said clamp bar means;
first draw means effecting an operative connection between said lock block and one said clamp actuator means;
second draw means effecting and an operative connection between said tray assembly and a second clamp actuator means;
knob means effecting an operative connection with said clamp bar means such that actuation of said knob means displaces said first draw means selectively to clamp said slide and lock blocks to said support assembly as well as said slide block to said housing and displaces said second draw means selectively to clamp said tray assembly to said housing.

6. An adjusting assembly, as set forth in claim 5, wherein:
a first brake pad means is interposed between said friction means presented from said slide block and said friction means associated with the first end portion of said housing; and a second brake pad means is interposed between said friction means presented from said tray assembly and said friction means associated with the second end portion of said housing.

7. An adjusting assembly, as set forth in claim 5, wherein said support assembly further comprises:
a mounting pin to, and extending upwardly from, the distal end portion of said mounting bar;
a retainer rotatably mounted on said mounting pin;
a pair of guide tubes extending upwardly from said retainer;
said lock block and said slide block cooperatively interacting with said guide tubes to effect the selective clamping action therebetween.

8. An adjusting assembly, as set forth in claim 7, further comprising:
detent means to determine the range of rotation between said retainer and the distal end portion of said mounting bar.

9. An adjusting assembly, as set forth in claim 4, wherein said locking means further comprises:
clamp bar means supported from said housing;
a plurality of clamp actuator means engaging said clamp bar means;
first draw means effecting an operative connection between said lock block and one said clamp actuator means;
second draw means effecting an operative connection between said tray assembly and a second clamp actuator means;
fulcrum means supported from said housing and engaging the medial portion of said clamp bar means;
a release actuator means operatively engaging said second draw means;
spring means which bias said second draw means to secure said tray assembly frictionally to said housing;
a lever means to move said release actuator means operatively to overcome said spring means and thereby not only to release said first draw means to permit selected elevational movement of said housing with respect to said support means and to permit selected articulation of said housing with respect to said support means but also to release said second draw means to permit rotation of said tray assembly with respect to said housing

10. An adjusting assembly, as set forth in claim 9, wherein:
said tray assembly has a frame from which a tray member is supported;
a recess is provided in said tray frame to receive said release actuator means;
a pair of laterally spaced journal means are presented from said tray frame for access within said recess;
a pair of bearing surfaces are presented from said release actuator means operatively to engage said journal means such that actuation of said lever means swings said release actuator means about one or the other of said journal means.

11. An adjusting assembly, as set forth in claim 10, wherein:
said release actuator means presents a cam surface that operatively engages said second draw means and said spring means such that swinging said release actuator means releases the locking means operated by said second draw means and compresses said spring to reengage said locking means upon release of said lever means.

12. An adjusting assembly, as set forth in claim 11, wherein:
said release actuator means is penetrated by a slotted aperture which permits access to said second draw means for adjusting second draw means;
a channel is recessed into said release actuator means to receive said lever, said channel being oriented in space vertical relation relative to said slotted aperture and being disposed substantially transversely with respect thereto.

13. An adjusting assembly, as set forth in claim 4, wherein said locking means further comprise:
clamp bar means supported from said housing;
clamp actuator means engaging said clamp bar means;
first draw means effecting an operative connection between said lock block and one said clamp actuator means;

fulcrum means supported from said housing and engaging the medial portion of said clamp bar means;
second draw means effecting an operative connection between said tray assembly and a knob means;
thrust plate means interposed between said knob means and said clamp bar means such that actuation of said knob means pivots said clamp bar means about said fulcrum means selectively to clamp a portion of said support assembly between said clamp block and said slide block as well as to clamp said first friction means between said slide block and said housing and said second friction means between said tray assembly and said housing.

14. An adjusting assembly, as set forth in claim 4, wherein said locking means further comprise:
draw means effecting an operative connection between said lock block and a first knob means such that actuation of said first knob means displaces said first draw means selectively to secure said slide and lock blocks frictionally to said support assembly and also selectively to secure said housing to said support assembly;
second draw means effecting an operative connection between said tray assembly and a second knob means such that actuation of said second knob means displaces said second draw means selectively to secure said tray assembly to said housing.

15. An adjusting assembly, as set forth in claim 1, wherein:
said arm assembly is articulated with respect to said support assembly about an articulating axis that is disposed substantially horizontally;
said tray assembly is pivotal with respect to said arm assembly about a pivotal axis that is disposed substantially horizontally; and, locking means are provided selectively to secure the pivotal position of said tray assembly with respect to said arm assembly and the articulated position of said arm assembly with respect to said support assembly.

16. An adjusting assembly, as set forth in claim 15, wherein:
said arm assembly has a housing which defines said first and second end portions of said arm assembly;
a friction means is associated with each said first and second end portions defined by said housing;
said support assembly has a friction means disposed in opposition to the friction means associated with said first end portion of said housing;
said tray assembly presenting a friction means disposed in opposition to said friction means associated with the second end portion of said housing;
locking means selectively to bring said friction means presented from said support means into operative cooperation with friction means associated with the first end portion of said housing as well as to bring said friction means associated with said tray assembly into operative cooperation with the friction means associated with the second end portion of said housing.

17. An adjusting assembly, as set forth in claim 16, wherein:
draw means are provided to effect an operative connection between the friction means presented from said support means and the friction means associated with the first end portion of said housing;
second draw means to effect an operative connection between the friction means presented from said tray assembly and the friction means associated with the second end portion of said housing;
said locking means comprises spring means which bias said first and second draw means to effect the operative connection established by each.

18. An adjusting assembly, as set forth in claim 1, wherein:
said support assembly comprises a stanchion which provides a fixed elevation between said support assembly and said articulation axis.

19. An adjusting assembly as set forth in claim 18 wherein:
first draw means effect an operative connection between the friction means presented from said stanchion and the friction means associated with the first end portion of said housing;
second draw means in effect an operative connection between the friction means presented from said tray assembly and the friction means associated with the second end portion of said housing;
said locking means comprises knob means which effects the operative connection established by said first draw means and spring means which bins said second draw means to effect the operative connection established thereby

20. An adjusting assembly as set forth in claim 18 wherein:
draw means arc provided to effect an operative connection between the friction means presented from said stanchion and the friction means associated with the first end portion or said housing;
second draw means are provided to effect an operative connection between the friction means presented from said tray assembly and the friction means associated with the second end portion of said housing;
said locking means incorporates knob means which are operatively attached to each said first and second draw means to effect the operative connection established by each.

21. An adjusting assembly as set forth in claim 18 wherein said locking means further comprises:
clamp bar means supported from said housing;
clamp actuator means engaging said clamp bar means;
first draw means effecting an operative connection between said stanchion and one said clamp actuator means;
second draw means effecting an operative connection between said tray assembly and a second clamp actuator means;
knob means effecting an operative connection with said clamp bar means such that actuation of said knob means displaces said first draw means selectively to clamp said housing to said stanchion and also displaces said second draw means selectively to clamp said tray assembly to said housing.

22. An adjusting assembly, as set forth in claim 18, wherein said locking means further comprise:
clamp bar means supported from said housing;
clamp actuator means engaging said clamp bar means;
first draw means effecting an operative connection between said housing and said stanchion;
fulcrum means supported from said housing and engaging the medial portion of said clamp bar mean;
second draw means effecting an operative connection between said tray assembly and a knob means;
thrust plate means interposed between said knob means and said clamp bar means such actuation of said knob means pivot said clamp bar means about said fulcrum means selectively to clamp said housing to said stanchion as well as to clamp said tray assembly to said housing.

23. An adjusting assembly, as set forth in claim 18, wherein:
said arm assembly has a housing which defines said first and second end portions of said arm assembly;
a friction means is associated with each said first and second end portions defined by said housing;
said stanchion having a friction means disposed in opposition to said friction means associated with the first end portion of said housing;
said tray assembly presenting a friction means disposed in opposition to said friction means associated with the second end portion of said housing.

24. An adjusting assembly, as set forth in claim 23, wherein:

a first brake pad means is interposed between said friction means presented from said stanchion and said friction means associated with the first end portion of said housing; and a second brake pad means is interposed between said friction means presented from said tray assembly and said friction means associated with the second end portion of said housing.

25. An adjusting assembly, as set forth in claim 24, wherein said support assembly further comprises:
a mounting pin secure to, and extending upwardly from, the distal end portion of said mounting bar; and, said stanchion cooperatively engaging said mounting pin for rotation about a vertical rotational axis.

26. An adjusting assembly, as set forth in claim 25, further comprising:
detent means to determine the rang of rotation between said stanchion and the distal end portion of said mounting bar.