US3177952A

US3177952A - Impact tool

Info

Publication number: US3177952A
Application number: US130127A
Authority: US
Inventors: Warren H West
Original assignee: Cambridge Thermionic Corp
Current assignee: Cambridge Thermionic Corp
Priority date: 1961-08-08
Filing date: 1961-08-08
Publication date: 1965-04-13
Anticipated expiration: 1982-04-13

Description

W. H WEST April 13, 1965 IMPACT TOOL Filed Aug. 8I 1961 Pfarrei@ jz wif H77 'yf United States Patent O 3,177,952 llt/@ACT T001.

Warren H. West, Seabrook Beach, N11., assigner to (Iambridge Thermionic Corporation, Cambridge, Mass., a corporation of Massachusetts Filed Aug. 8, 1961, Ser. No. 130,127 Claims. (Cl. 173-121) The lield of this invention is that of impact tools and more particularly such tools capable of delivering impacts in either of two directions.

In the electronic arts, such as for example in the computer elds, use is frequently made of small taper-piu connectors and terminals. Such terminals establish electrical Contact by means of frictional engagement between correspondingly tapered pins and sockets. The high pressure and surface wiping action desirable in electrical contacts are created by a wedging engagement. To aecomplish the wedging Without resorting to relatively high steady pressure which might damage miniaturized apparatus, it is preferable that such pins be set in with a sharp impact of short duration.

In some applications, such as the wiring of computer patch panels, it is also desirable that these pin connectors be easily removable. For that purpose also steady high forces should be avoided. The panels into which these connections are made are usually made of insulating material of somewhat limited strength and they usually have a great number of perforations so as to accommodate a multiplicity of terminals. Accordingly, if the mass and inertia rather than the strength of these panels provide the counteracting force in the extraction of the pin connectors, the danger of breakage is reduced. An impact will provide the high pressure of short duration needed to utilize the inertia in this fashion.

Objects of the present invention are to provide an impact tool which can deliver a hammer blow in either of two directions, which delivers blows in either direction without alteration or adjustment, which is compact with a minimal number of parts and of light weight, which is highly reliable, which permits easy reaching into and operation within crowded surroundings, which makes eiicient use of the operating force available, and which is of simple and inexpensive construction.

The substance and nature of the present invention can be briey summarized as to characteristic aspects thereof as follows:

Impact tools according to the invention have an elongate frame carrying a shaft slidably mounted therein and having two abutments, a unitary hammer or block longitudinally slidable with respect to both the frame and the shaft, latch means for releasably locking the shaft and hammer together for longitudinal travel, and spring means tending to locate the hammer at a normal position relative the frame. The latch means lock in position and during relative movement of locked hammer and shaft relatively to the frame for a given distance on either side of the normal position. Upon movement beyond the normal position, shaft and hammer are unlocked and the spring means causes the hammer to deliver a blow to one of the abutments. In this manner, the hammer lmass and inertia can be applied in either direction, for setting or pulling respectively, with the same tool.

These and other objects, inventive aspects, and advantageous results will appear from the following detailed description of a practical embodiment thereof illustrating its novel characteristics.

ice

The description refers to a drawing in which FIG. l is a plan view in longitudinal section of a double acting impact tool; i

FIG. 2 is a section on line 2-2 of FIG. l;

FIG. 3 is a plan view of a shaft fitment in engagement with a taper pin terminal.

As shown in the drawing, a shaft 10 is slidably mounted in a sleeve-like outer frame 12. For purposes of assem.- bly the frame 12 is constructed in three parts, a nose piece 14, a central part 15, and an end cap 16, which parts are threaded each one into the next.

The shaft 10 is urged towards a normal longitudinal position Within the frame 12 by springs 13 and 19 which operate, through

washers

20 and 21, on a split ring 22 fitting in an annular groove 23 in the shaft. The fixed ends of the springs 13 and 19 bear respectively on la shoulder 25 on the nose piece 14 and a shoulder 26 on a tubular insert 28 which is provided for that purpose and is threaded into the rearward end of the nose piece 14.

A hammer Sil is slidably mounted with respect to both the shaft 1@ and the frame 12, iitting within the frame and externally of and concentric with the shaft. The movement of the hammer relative the shaft is limited by an abutment shoulder 55 of the shaft in the one directiom and by a nut abutment 56 on the end of the shaft in the other. The nut 56 is provided with a lock nut 57. The hammer, like the shaft, is urged towards a normal position relative the frame 12 by a pair of

springs

32 and 33. `Washers 35 and 36 are interposed between the springs and the hammer and, by means of shoulders 37 and 38 on the inner surface of the central part 15 of the frame 12, these washers limit the expansion of their respective springs without restricting the further movement of the hammer 39 in either direction. The fixed ends of the

springs

32 and 33 bear against the insert 28 and the end cap 16 respectively.

Fitted within a transverse bore 40 in the hammer 30 is a latch key 42. This key also has a bore 43 of diameter sufficient to permit the free passage therethrough of all adjacent portions of the shaft 10. The shaft has a groove or neck 45 which, when both the hammer 30 and the shaft 1l) are in their respective normal positions, is located within the bore 43 of the key 42. When the groove 45 is thus located a spring 47, fastened by the rivet 48 to the hammer 3@ urges the key 42 laterally so Ithat the bore 43 is eccentric with respect to the shaft and so that the one side of the key engages the groove 45 in the shaft. The opposing end 46 is thereby caused to project somewhat beyond the bore 40 into a somewhat enlarged portion 49 of the frame 12 having tapered ends 56 and 51.

With the key 42 so disposed the hammer 30 and the shaft are locked together for longitudinal movement within the frame 12. The operation of the device is then as follows:

1f, with the parts thus locked, the shaft 10 is longitudinally displaced in either direction relative the frame 12 or, conversely, if the shaft is iixed and the frame is moved, the hammer 3@ also will be displaced within the frame, will engage one of the adjacent washers 35 or 36, and will compress the

corresponding spring

32 or 33.

tric relation with the shaft ttl. rThis movement will unlock the hammer from the shaft and Will permit the compressed hammer spring to drive the hammer towards its normal position. However, as the shaft 16 is at this point also displaced from its normal position the hammer will encounter either the shoulder 55 or the nut 56 before reaching its normal position and will thereby deliver a sharp hammer-blow in one of the direction to the shaft `and to the article associated with the shaft or a iitment thereon.

For use in inserting and extracting components such as taper pin electrical terminals the projecting end of the shaft has threaded onto it a iitment 6@ adapted to engage the terminal end of a taper pin 65 as shown in FIG. 3. The pin enters the titment from the side and the groove 61, engaging a corresponding collar 66 of the pin, permits either a driving or an extracting force to be applied. t

To set a pin in its socket the fitment is slipped over the end of the collar and the frame is driven forward until the hammer releases and snaps forward. The operation in extracting a pin is similar except that the frame is drawn back. No adjustment needs to be made. It should be noted that the steady force applied by the operator to the frame 12 and correspondingly the bending force applied to a terminal board is substantially less than the force actually required to properly set or to withdraw va pin because energy is stored in the hammer springs over the whole displacement of the frame and is released suddenly as an impact of high force and short duration. Being of short duration the actuating force used in making or separating the wedge joint works more against the inertia of a terminal board than against its strength. The :force which the operator of the device must supply is also correspondingly lessened.

Advantages of this device are, like devices of this type generally, that it is compact and of light Weight and ma easily be operated under crowded conditions. The particular advantage of the present invention is that it may, without adjustment or alteration, be used both to set and to extract taper pin electrical terminals. Further advanrtages of the preferred embodiment shown are that it makes efficient use of the driving force provided by a single hammer mass and in that the expansion of the opposing hammer spring is limited so that the hammer may be influenced solely by the aiding spring.

It should be understood that the present disclosure is for the purpose of illustration only and that the present invention includes all modifications and equivalents falling Within'the scope of the appended claims.

I claim:

1. An impact tool comprising: an elongate frame; a shaft longitudinally slidable relative to said frame; a hammer longitudinally slidable along said shaft relative to both frame and shaft; spring means tending resiliently to locate said shaft in the longitudinal direction at a normal position -With respect to said frame; second spring means tending resiliently to locate said hammer at a normal position with respect to said frame; spring-loaded latch means carried by said hammer for releasably locking said shaft and said hammer together in said normal positions; a. pair of abutments carried by said shaft and located in spaced relation on either side of said hammer; and means on saidframe releasing said latch means when said hammer is displaced a predetermined distance in either direction from said normal position; whereby, When said shaft `is displaced in either longitudinal direction with respect to said frame, said hammer will rst be carried with said shaft until said latch is released and then will return towards its normal position under the influence of said second spring means thereby delivering a hammer blow to said shaft at one of said abutments.

2. An impact tool comprising: an outer sleeve; a shaft slidably mounted in said sleeve; a hammer slidable on i. said shaft with respect to both said sleeve and said shaft; spring means tending to locate said shaft at a normal position with respect to said sleeve; a spring tending to drive said hammer in one longitudinal direction with respect to said sleeve; a stop on said shaft for limiting the expansion of said spring without restricting the further movement of said hammer relatively to said sleeve a second spring tending to drive said hammer in the opposite longitudinal direction with respect to said sleeve; a second stop on said shaft limiting the expansion of said second spring without restricting the further movement of said hammer relatively to said sleeve, said stops determining a normal position for said hammer; a latch for releasably locking said shaft and said hammer together in said normal positions of hammer and shaft respectively; a pair of abutments carried by said shaft and located in spaced relation on either side of the hammer in normal position; and means on said frame for releasing said latch when said hammer is displaced relative to said frame a predetermined distance in either direction from said normal position.

3. An impact tool comprising: an outer sleeve; a shaft slidably mounted in said sleeve; a hammer concentric with said shaft and slidable with respect to both said sleeve and said shaft; spring means tending resiliently to locate said shaft in the longitudinal direction at a normal position with respect to said sleeve; a spring concentric with said shaft tending to drive said hammer in one irection relative to said sleeve; a washer interposed between said spring and said hammer; a shoulder on the `inner surface of said sleeve against which the outer portion of said washer can bear for limiting the expansion of said spring Without restricting the further movement of said hammer; a second spring concentric with said shaft tending to drive said hammer in the opposite direction relative to said sleeve; a second washer interposed between said second spring and said hammer; a second shoulder on the inner surface of said sleeve against which the outer portion of said second washer can bear for limiting the expansion of said second spring Without restricting the further movement of said hammer, said shoulders and said washers determining the normal position for said hammer; a spring loaded latch carried by and transversely slidable within said hammer for releasabiy engaging said shaft in said normal positions of shaft and hammer respectively; a pair of shoulders on said shaft located in spaced relation on either side of said hammer and frame when those parts are in their normal positions; and cam means on the inner surface of said sleeve for driving said latch laterally out of engagement with said shaft when said hammer is displaced relative to said frame a predetermined distance in either direction from its normal position.

4. An impact tool comprising: an elongate frame; a shaft longitudinally slidable relative to said frame; a hammer longitudinally slid-able along said shaft relative to both frame and shaft; a plurality of opposing spring means tending to locate the hammer at a normal position with respect to said frame; means for locking said hammer and said shaft together in said normal position; means on said shaft for limiting longitudinal movement in either direction of said hammer relative to said shaft and providing impact upon such limiting; and means on said frame for unlocking hammer and shaft when they are moved relatively to the frame a predetermined distance in either direction from said normal position, whereupon the hammer exerts an impact on one of the limiting means and hence on the shaft.

5. An impact tool comprising: an elongate frame; a shaft longitudinally slidable relative to said frame and having impact abutments; unitary hammer means movable longitudinally of said shaft intermediate said abutments and capable of delivering hammer blows in either direction against said abutments; opposing spring means intermediate said frame and said hammer means capable of exerting a force to initiate said blows; unitary latch means for locking said shaft to said hammer means in a normal position and upon movement from said position in either direction for given spring tensioning dis- 5 tances; and means for releasing said latch means upon displacement of frame and shaft through one of said distances, initiating a spring blow whose force is directed opposite to the displacement of the shaft.

References Cited bythe Examiner UNlTEDV STATES PATENTS BROUGHTC'N G. DURHAM, Primary Examiner.

NEDWIN'BERGER, Examiner.

Claims

5. AN IMPACT TOOL COMPRISING: AN ELONGATE FRAME; A SHAFT LONGITUDINALLY SLIDABLE RELATIVE TO SAID FRAME AND HAVING IMPACT ABUTMENTS; UNITARY HAMMER MEANS MOVABLE LONGITUDINALLY OF SAID SHAFT INTERMEDIATE SAID ABUTMENTS AND CAPABLE OF DELIVERING HAMMER BLOWS IN EITHER DIRECTION AGAINST SAID ABUTMENTS; OPPOSING SPRING MEANS INTERMEDIATE SAID FRAME AND SAID HAMMER MEANS CAPABLE OF EXERTING A FORCE TO INITIATE SAID BLOWS; UNITARY LATCH MEANS FOR LOCKING SAID SHAFT TO SAID HAMMER MEANS IN A NORMAL POSITION AND UPON MOVEMENT FROM SAID POSITION IN EITHER DIRECTION FOR GIVEN SPRING TENSIONING DISTANCES; AND MEANS FOR RELEASING SAID LATCH MEANS UPON DISPLACEMENT OF FRAME AND SHAFT THROUGH ONE OF SAID DISTANCES, INITIATING A SPRING BLOW WHOSE FORCE IS DIRECTED OPPOSITE TO THE DISPLACEMENT OF THE SHAFT.