US2140223A - Power wrench - Google Patents

Description

B. N. FOSTER 2,140,223

PWER WRENCH Filed oct. 1 19:56 4 Sheets-sheet 1 @w wwwa/1L Dec. 13, 1938.

Dec. 13, 193s. l B N. @STER 2,140,223

POWER WRENG H Filed Oct. l, 193e r 4 sheets-sheet 2 Dec. 13,V 1938..

, B. N. FOSTER POWER WRENCH 4 sheets-sheet 3' Filed 001;. l, 1936 B. N. FOSTER' POWER WRENCH Dec. 13, 1938.

Patented Dec. 13, 1938 UNITED STATES PATENT oFFicE POWER WRENCH Application October 1, 1936, Serial No. 103,578

10 Claims.

The invention relates generally to power wrenches and has for an object to provide a novel form of power wrench embodying a staticnarily supported power source, a Wrench head shiftable toward and from operative engagement with the element-to-be-turned, and novel control devices including a single handle movable a distance longitudinally and laterally to fined the element-to-be-turned, an additional distance longitudinally to embrace said element, and thereafter laterally to initiate operation of the power source eiective to impart rotation to said wrench head.

Another object of the invention is to provide a power wrench of the character stated in which the control devices include friction clutch connections which cause the wrench head to move with the handle during its lateral movements prior to effective application of power from the power source, and thereafter permit relative movement between the handle and the wrench head'in a manner for automatically holding said handle in the position controlling the application of power.

Another object of the invention is to provide a reversible electric motor, a longitudinally and laterally shiftable wrench head carrying shaft having driving connection with the motor, a. control handle having friction clutch connection with the shaft and movable a distance longitudinally and laterally to iind the element-to-be-turned, an additional distance longitudinally to embrace the element and in either direction laterally only after the element has been fully embraced, and a control switch engageable by the handle in each direction of lateral movement following full embracement of the element for initiating operation of the motor in one direction or another.

Another object of the invention is to provide in a wrench of the character stated a. control handle having fully retracted, intermediate, and fully projected positions in the first of which positions it is engageable with a circuit closing switch for controlling a signalling or positioning circuit, in the second of which it is aiorded limited freedom for finding the element-to-be-turned, and in the third of which, having fully embraced the element, it is free to move a greater distance in either direction laterally to engage one or another control switch for initiating power application to the wrench head in one direction or another.

With the above and other objects in view that will hereinafter appear, the invention further resides in the novel details of construction and and forms therewith a gear chamber I2.

combination and arrangement of parts rst fully described in the following detailed description, then particularly pointed out in the appended claims, reference being had to the accompanying drawings, in which:-

Figure 1 is a vertical'longitudinal section illustrating the invention.

Figure 2 is a plan view and part horizontal section o'f the parts shown in Figure 1.

Figure 3v is a front end elevation. l0

Figure 4 is a rear end elevation.

Figure 5 is a vertical cross section taken on the line 5 5 on Figure 2-.-

Figure 6 is a vertical cross section taken on the line '6 6 on Figure l. l5

Figure 7 is avertical cross section taken on the line 'l-- on Figure 2.

Figure 8 is a Vertical cross section taken on the line 3-8 on Figure 1.

In the practical development of the invention I provide an electric motor 5 supported as at 6 upon a stationary frame 'I. The motor 5 preferably iso-f the reversible, low inertia type having 'high vtorque characteristics and operable at a synchronous speed of about 1800 R. P. M; 25

A two part head portion 8 is flanged secured as at 9 to the frame proper and a front cover plate I0 is ange secured as at II said frameV See Figures 1, 2 and 4; 30 C A relatively long sleeve I3 is rotatably supported in bearings I4 formed in the frame 'I and cover l0, and the sleeve is axially lbored and grooved as at I5 and equipped with a radially projected lug I6. The lug I8 is engageable with a lug I1 projecting longitudinally from the hub I8 of a large driven gear I9 rotatably supported upon the sleeve. See Figures 1 and 6. Thus mounted, the gear I 9 will be caused to rotate with `the sleeve when the lugs I6 and I l are contacting in a given direction, and the sleeve will be free to rotate independently of the gear in either direction until the lost motion occasioned by any existing spaced relation between the lugs I6 and .Il has been taken up. The purpose for this lost motion driving connection between the sleeve I3 and the driven gear I9 will become apparent as the description progresses.

' The driven'gear I9 meshes with a small driver pinion 20 ofthe spur type which is rotatably supported' as at 2l .on the motor shaft 22 and driven by la suitable driving member 23 which is keyed as at 24 to the motor shaft and rotatably supported as at 25 in the cover Iii. See Figure 1.

, A ribbed spline shaft 26 is rotatable with and longitudinally slidable in the sleeve |3. The shaft 26 extends beyond the cover I0 and has removably secured thereon a wrench head 21 axially bored at 28 and equipped with nut or bolt head receiving grooves 29 as shown in Figures 1 and 3 of the drawings. As shown in Figure 3, the grooves 29 are shaped for embracing a nut, bolt head or other element-to-be-turned of the square type.. and two sets or eight such grooves are provided so that the element-to-be-turned can be found and embraced with a minimum of rotative or lateral movement of the wrench head. The nding and embracement of the elementtobeturned is further facilitated by chamfering the receiving ends of the grooves as indicated at 38.

The wrench head proper designated 21 is removably secured as at 3| to a-pair of plates 32 which are shaped so as to together form anannular groove 33 surrounding the shaft 26. 'The ribs of the shaft 26 are similarly grooved as at 34, and a split lock ring 35 is positioned in the groove-way thus formed. It will be obvious by reference to Figure 1 of the drawings that by removing the screws 3| the wrench head 21 may be removed and replaced by another of appropriate size. The same screws secure the assembly of the wrench head 21 and the pair of rings 32, and when these parts are assembled, they are securely locked uponthe extended end of the drive shaft 26. See also Figure 8.

The other end of the shaft 26 extends beneath the hood portion 8 and is provided with the cylin drical reduction 36 on which a collar 31 is secured, said collar including a friction clutch face 38. The shaft end also includes a reduced and threaded end 39 on which a collar 40 is mounted and secured by a jamb nut i4 I. The collar 40 is provided with a friction clutchface 42 opposing the clutch face 38 before referred to.

A hub member 43 is rotatably mounted on the shaft portion 36 between the clutch faces, and a pair of bronze friction washers 44 are interposed between the opposite faces of said hub and the adjacent clutch faces 38 and 42, said Washers being spring pin keyed as at 45 to move with the hub 43. See Figure 1. A lever or control handle 46 projects radially from the hub 43 and extends through a slot 41 formed in the hood 8. At each side the hub 43 is equippedwith a radially projected cam pin 48 -the purpose of which will be described later.

It will be observed by reference to Figures 1 and 2 of the drawings that the slot generally designated 41, and which is designed to accommodate longitudinal and lateral movement ofthe control lever, includes a keeper or rest recess 49 in which the lever may be yieldably retained, as shown in Figures 2 and 6 of the drawings, by a spring pin 50. The slot-way includes an intermediate widened portion 5| for permitting a limited amount of lateral movement of the control lever and a forward enlargement 52 for permitting a greater amount of lateral movement of said lever. The slot-way portion V5| is wide enough to permit any lateral movement of the control lever necessary to the proper finding of the element-to-be-turned by the wrench head`21, and until such element is properly found it is obviously impossible to move the control lever forwardly into the wider `slot-way portion 52.

The lever can be moved into the sloteway portion 52 only after the element-to-be-turned has been found and completely embraced.

When the control lever .hasibeen moved foriboth. fEach such device comprises a presser head 54 adjustably mounted for axial extension in a ythreaded bore 55 formed in a plunger sleeve 56 slidable ina bearing 51 provided therefor in the lower half of the hood portion 8. The bearing boreiisclosed by a sleeve nut 58, and a spring 5,9 is interposed between said nut and a shoulder provided on the sleeve and serves to hold the sleeve against a retainer bar 68 removably sevcured to the hood carried bearing 51 as shown in Figure 2 of the drawings.

A jamb nut 6| secures the adjustment of the tappet or presser head 54, and the counter bore .62 in the sleeve 56 is closed by a screw head 63. A-coil spring 62 is interposed between the closure screw 63 and an actuator pin 65 slidable in and projected through a bore formed in the end of the sleeve 56 and yieldably presents said pin for engagement with the plunger 66 of a motor control switch 61.

Any approved form of motor control switch may be employed. The one utilized as an example in this disclosure is covered by the patent to P. K. McGall, 1,960,020, issued May 22, 1934. The switch is of the normally open or circuit broken type, the circuit being completed each time the plunger 66 is pressed inwardly and again broken each time pressure on said plunger is relieved. Each of the control switches 61 is removably secured at 68 to the lower half of the hood 8 and is connected by suitable wiring through conduits 69, with the motor 5.

:It will be obvious by reference to Figure 5 of g `the drawings that when the lever is shifted to one side or the other the contact pin 48 will engage the proper tap-pet 54 and force the sleeve .5 6 from which it projects laterally causing the yieldably mounted pin thereof to actuate the switch plunger 66 and energize the motor circuit. Theswitches 61 are accessible through removable lcover plates 18.

Myimprovedpower wrench is adaptable to any of the uses to which power wrenches generally may be put, butpreferably is employed in conjunction with some movable part which serially presentsto the wrench head the elements-to-be- `turned thereby. Such equipments are to be found on machines embodying index turrets which present work and the clamping chucks to successive work stations.

Assuming that an element-to-be-turned has been positioned in axial alignment with the stationary frame supported wrench head 21, the

operator grasps the handle or control lever 46 .and moves it forwardly to bring the grooved and ,chamfered end 29, 33 thereof into engagement with said element. If the grooves 29 do not immediately embrace the element the lever can be moved laterally within the slot-way enlargement 5| so as to find said element or permit perfect registry of the grooves 29 with the element head,

vafter which the lever can be moved forwardly Yto completely embrace the element head. By reason of the arrangement of the grooves 29 as shown in Figure 3 of the drawings, the degree of lateral movement of the lever necessary in finding the element head or registering the same to enter the grooves is very slight. l

After the element-to-be-turned has been completely embraced by the wrench head 2'! the lever 46 can be moved to the right or the left to engage one or the other of the switch control devices 53 for initiating motor operation in one direction or another as desired.

During the finding of the element-to-be-turned the frictional contact between the lever plates 44 and the friction faces 38, l2 is sufficient to cause the wrench head 21 and the power transmitting connections to move with the lever. By reason of the provision of the friction clutch connections and the gears I9 and 2i! of the spur type, this finding operation is possible. After moto-r operation in one direction or another is initiated as above described, the same friction equipment permits the shaft 2G to rotate while the lever l5 remains stationary, the friction clutch equipment serving to constantly urge the lever in the proper direction for maintaining the switch contact and the completion of the motor energizing circuit incident thereto.

The lost motion power transmitting relation of the lugs it and il enables the starting of each wrench operation with a hammer blow effective to assure proper starting of each element turning function. Upon the completion or setting of the turned element in either direction the motor stallsand with the torque thus relieved the frictional urge upon the lever 46 is relieved and the selected motor circuit is broken.

If desired an additional circuit controlling device 'H and switch '12, preferably identical with the devices 53 and switches 67 hereinbefore described, may be provided and so positioned as to be engaged by the end of the shaft 26 ea'ch time the control lever 4E is returned to its retracted position as shown in Figures 1 and 2 of the drawings. This switch may be suitably connected to control the indexing which serves to position the element-to-be-turned for engagement by the wrench head 2l, or it may be utilized to actuate a signal or for any similar function. When it is employed for controlling the positioning of the element-to-be-turned it adds to my equipment the feature of providing a single lever capable not only of finding the element-to-beturned, embracing the element-to-be-turned, controlling operation of the power source in the desired direction and the automatic retaining of the power oircuit connections until the element turning operation is complete, but also the automatic controlling of serial presentation of elements-to-beturned for engagement by the wrench head.

From the foregoing description taken in connection with the accompanying drawings it is thought that the novel details of construction, the manner of use and the advantages of my invention will be readily understood by those skilled in the art to which it relates.

l. In a power wrench, a wrench head, means for applying driving power to said head, a single control member operable first with the head in a longitudinal direction to apply the head to completely embrace an element-to-be-turned and then laterally for initiating operation of Said power applying means, and friction connections between said driving means and said control member causing said means and member to move together during the applying of said head but permitting said means to move independently of said member during turning of said element.

2. In a power wrench, a. wrench head, means for applying driving power to said head, a single 'I control member operable rst with the head in a longitudinal direction to apply the head to completely embrace an element-to-be-turned and then laterally for initiating operation of said power applying means, and friction connections between said driving means and said control member causing said means and member to move together during the applying of said head but permitting said means to move independently of said member during turning of said element and hold said member in its laterally shifted operation initiating position.

3. In a power wrench, a Wrench head, an electric motor having power transmitting connections with said head, .a motor control switch, a single and permit independent movement of said head during turning of said element.

4. In a power wrench, a wrench head, a reversible motor having power transmitting connections with said head, control devices for con` trolling operation of the motor in one direction or another, a single control member movable for applying the head to an element-to-be-turned and into engagement with one or the other of said devices for initiating operation of said motor in one direction or another, and friction connections between said member and said power transmitting connections causing said member and head to move together during the applying of said head and serving to hold said member against the selected motor control device and permit independent movement of said head during turning of said element.

5. In a power wrench, a wrench head, means for applying driving power to said head, a pair of spaced power application initiating control devices, and a single control member movable forwardly and laterally, forwardly to first cause said head to find and embrace an element-to-beturned, and laterally to engage one or the other of said control devices for initiating power application in one direction or another, and means to prevent such lateral movement except after complete embracement of said element.

6. In a power wrench, a wrench head, means for applying driving power to said head, a pair of spaced power application initiating control devices, a single control member movable forwardly and laterally, forwardly to nrst cause said head to nd and embrace an element-to-be-turned, and laterally to engage one or the other of said control devices for initiating power application in one direction or another, means to prevent such lateral movement except after complete embracement of said element, and means for automatically holding said member in engagement with the selected control device during the application of power.

7. In a power wrench, a wrench head, means for applying driving power to said head, a pair of spaced power application initiating control devices, .a single control memberlmovable-forwardly and laterally, forwardly to first cause said head to find and embrace an element-toebe-turned, and laterally to engage one or the'otherof lsaid control devices for initiating power application in one direction or another means to prevent such lateral movement except after complete embracement of said element, and means for constantly urging said member to retain its engagement vwith the selected control device throughout the duration or the application of power.

8. In a power wrenchfa reversible driving motor, spur gear power transmitting connections, a Wrench head rotatable with and longitudinally movable relatively to said-connections'for finding and embracing and thereafter imparting rotation to an element-to-be-turned, means manually'actuated for moving said wrench headfmeans engageable by ysaid manually actuated means for setting the motor into operation in either direction, and ylost motion connections in said power transmitting connections for initiating power operation of the wrench head-withahammer'blow.

9. In a power wrench, a driving motor, power transmitting connections-'including a driven gear, a wrench head and a carrying shaft therefor movable relatively longitudinally of and rotatable with said gear for finding and-embracing and thereafter imparting rotation to an element-to- 'be-turnecL a control lmember having a hub enfcirclingand'rotatable relative to said .shaft, fric- .tion1 discs,fmovable with theshaft and frictionally igrippingsaid hub, afmotor vcontrol device a'ctu- .ableby alateralmovement of-said member, and

means provided-with acontrol device accommo- .dating guideway including laterally directed portions positioned for permitting said lateral move- 'ment only after the element-to-be-turned has r"been completely embraced.

10. In a power wrench; .a wrench head; a power Y motor having driving connection with said head;

apai-r of control switches for 'controlling operation of the motor in one direction or another;

a single Acontrol lever associated with the wrench head and the motor and the switches and having andanother switch for 'controlling indexing of a iWork support effective to serially present nuts in `position for being acted upon by the wrench `headand actuated upon retraction of the lever vinto its retracted position whereby indexing cannot be accomplished unless the -wrench head is fully v,retracted from engagement with the nut .last turnedvinto set position by the wrench head.

BENJAMIN NORTON FOSTER.

Images