US2381480A

US2381480A - Clamp

Info

Publication number: US2381480A
Application number: US531265A
Authority: US
Inventors: Martin L Albrecht; Birn Johann George
Original assignee: F W Brehmer Machine & Tool Co
Current assignee: F W Brehmer Machine & Tool Co
Priority date: 1944-04-15
Filing date: 1944-04-15
Publication date: 1945-08-07
Anticipated expiration: 1962-08-07

Description

Patented Aug. 7, 1945 f tum of Ohio Ourinvention relates to clamps,=particularly of thetype'wherein there is afixed table or base or jaw on which work or a jig or 'fixtureis placed and in which a movable jaw'is moved'into clamp ing position against the work to hold it in posi- So far as we are advisedfin connection with previously designed clamps 'of the type 'to'which.

our invention relates, there has never beenprovided a clamp whichpermits a fri'ctionally clamped work holding condition which i's readily releasable by manual actuation of the same hail dle'by' whichthework is originally clamped. All

' v ery effectual operation," we accomplish by that certain combination and arrangement of parts of which we have shown'a preferred embodiment lnthedrawingsz Figure 1 is'an end eleVa sembly. V

Fi'gureZis'asideelevatiom a j Figure 3 1s a vertical "section as 1 would appear 'along'theliri'e3 3'in-Figure 1; a

Figure"4 is' a lateral section' 'as would appear along helinefir eiF a rez i re a'is" on of a preferred "as lateral section as would ap- ISO 3 pear alcn'g the'linei J in Figure 2, excepting that in Figure 4a the parts have been advanced'to frictional interlocking condition.

' Figure 5 is a sectional view of a modified type of frictional interlock.

Figure 6 is a vertical section along the line 6-6 of Figure 5.

Figure '7 is a sectional view showing a still further modification of the frictional interlocking mechanism.

Figure 8 is an end elevation of the parts shown in section in Figure '7. v

A housing, preferably cast in one piece, has a base portion I, an upright extension 2, and an enlarged tubular portion 3 which is bored to re- Y wn licationnpriii5,1944,seria1-No..531,265

scams. (c1.1'92 s')"" ceive the r movable {clamping jaw member 4. w On the base there is a tablefi-uponwhichwork as indicated at 6 in dotted lines is usually supported. The clamping operation consistsinmoving the movable clamping member 4 .so that its lower surface 'e'ngagesthe upper surface of the work and thusholds it in clamped position. 7 It will be obvious that whetherjthe table15 is or is'not adjustable in an upward direction forms nopart of our invention since our invention is specifically related to the mechanism for actuating the'elampingjaw1. The housing has a boss I counterboredasindi cated at 8' toreceive a spindle 9 which carries a pinion l0. A'shoulder'8a on the spindle has -a rotating fit against a shoulder Bbin the counter bored portion of the bossl The pinion i0 is in enga'gement with the rack ll formed in the adjacent surface of'the' clamp bar 4. I

A bushing I2 is fixedly mounted on the end of the'spindle 9, a convenient method of mounting the bushing being by means of a key such as is indicated at 13. The bushing is threaded as indicated at l4 anda nut I5 is threaded onto the threads of thebushing l2."- v

The nut I5 has ahandle 'lli integrally formed therewith or threaded thereto. Other methods of rotating the nut'l5 as by having holes therein with a detachable bar to fit Within thehole or holes will readily occur to those skilled in the art.

Referring-to Figure 4, it will be' observed that the mu: [5 mounted in the threads of the bushing l2 has a limited rotary movement, the normal position of the nut'being such'that aspaceas. indicated at Ilia in Figure 4 exists between'the inner surface of the nut and the s'urface'of the boss! ofthe'housing; v 1 The'end of the spindle is'threaded' and to hold the bushing in fixed position on the spindle a'nut I! and .washer l8are secured on the end of-the indl j Referring to Figures 4 and 4A, I have shown a preferred type of frictional interlocking dog, The dog consists of a cylindrical plunger l'9 having a rounded face 20. The plunger is mounted in a cylindrical recess 2| in the nut l5 and a spring 22 engages the nut and .tends to force the dog outwardly into contact with the inner surface of alzle annularly enlarged outer end of the bushing There is a detent recess 23 in the inner surface of the annularly enlarged end of the bushing and by comparing Figures 4 and 4A, it will be observed that after, by means of movement of the handle IS, the clamping jaw 4 has been moved into engagement with the work, further movement of the handle [6 causes the dog I9 to be moved up the surface of the detent to the position shown at 20a in Figure 4a. This movement compresses the spring 22, but it also permits such movement of the nut l5 as will cause its surface to frictionally engage the surfaceof the boss .1 as indicated at I6b in Figure 4a. The spring tension of the dog 20 in the detent is sufiiciently strong so that the rotation of the handle [6 normally rotates the shaft 9 and runs down the clamp 4 until the work The limited movement of the nut in the threads of is engaged. When the work is engaged further movement of the handle [6 causesrelative movement of the nut I5 in the threads "I The relative rotation of the .nut "li inthe threads l4 causes the inner surface of the nut to engage the outer surface of the boss 1 and the gap l6a becomes a frictional interlock as indicated at l 6b in Fig. 4A. As this movementproceeds, the

shaft 9 is pulled to the right and the shoulder 8a develops "a frictional interlock againstv the counterbored shoulder 8b. v

Thus there are two frictioninterlocks in opposed directions at'il 6b and-8b The dog running up the inclined wall llla causes' the frictional .-interlocks to remain under compression. It should be understood that'itisthe blocking not further rotary movement of the'shart 9 which, as the movement of the handle Ii is continued, causes-the dog to run up the detentJThus the manual or other application of pressure whichicauses movement-of the handle is cushioned by the flexible connection between the nut 15 and the mshing L2. The frictional interlock is only broken by countere rotation of'the handle. I 6, which rotation causes theparts to return to their normal operative position;

In Figures Eand 6 the construction of the parts is substantially the same as in 11 $04, the exception being that instead of a detent as shown at 23 in Figures 4 :and4a, there is a cam surface fia arran-ged in such manner that-movement of the handle'causesithe .dog to run up the .cam surface 23aresulting' in aninterlock of the pants in exactly the same manner asinthe firstmodification of mechanism which we have described.

A slightly difierentxarrangement is illustrated in Figures 7 and 8 wherein the bushing does not have theannularly enl'arlgedend as'illustrated in Figures i and Ala, but insteadhas an annular por-: tion I 2a vwhich "has a camssurfaice :23b. In this modification there is a boss 24 having a cylindri cally'recessedportion llwwhich receives the dog [9a. The 1dog isvurged na/dia'lly toward the axis of the spindle 9 :by means of a spring 2211.

In the modificationgof Figures '7 and 8 after the handle has been rotatedto =1causef ciamping of the work, further movement of the, handle causes the dog 19a to run up the cam surface 231). This permits sufficient movement to close upthe gap I60 and cause a frictional interlock between the inner surface of the nut and the outer engaging surface of the boss 1, to be opposed by the frictional interlock of the annular shoulder of the'spindle with the counterbored recess in the boss.

It seems essential for the purposes of my invention that the mounting of the nut be such that a limitedtrotary movement of the nut is possible in the threads of the bushing, although, if it were possible to so construct the clamp, the bushing might be made as an integral part of the spindle.

the bushing must also cause the nut to advance toward a :position of frictional engagement with Qthesurface of theboss, and this must be opposed by a frictional interlock of the shoulder on the spindle against an annular shoulder of the boss. The dog, which is spring pressed'so as to ride up on a cam surface as soon as the clamping jaw engages the work, is radially spaced from the axis of thezspindleii. l

t "Ilhe particular position ofithe do which rides u-prthe cam surface might be interchanged so that thed-og is carried bythe bushing and the cam surface is on the nut; Modification and rearrangement of parts to accomplish the same purpose Will s-readily occur togthose skilledin the art without departing from the principle of our invcntion.

Having thus described our-invention, what we clatim as new. and desire to secure "by Letters Paten. is: -1. A---1ocking device ,for a rotatable shaft comprising a bushinghaying a threaded neck fixedly mounted on said shaft, a nut mounted for limited rotar-ymovement on said threaded neck, a manually adjustable handle associated with'said nut, and a springactuated dog mounted in said nut ina gtaosition radially spaced from the axis ofsaid shaf 1 2. A 'lockingdevice for a rotatable shaft comprising 1a bushing havin a threaded neck fixedly mounted on said shaft; a nut mounted for limited rotary movement onsaid threaded neck, a manua-llyadiustable handle associated with said nut, and a spring actuated dog mounted in said nut in apposition radially spaced from the axis of said shaft, said spring-actuated dog adapted to engage said bushing forcausing a resiliently cushioned frictional interlock between said nut and bushing.

3. .A locking device for a-rotatabl'e shaftcomprising a bushing having a threaded neck fixedly mounted on said shaft, a nut mounted for limited rotary movement on said threaded neck, means for rotating said nut,. and a spring actuated dog mounted in. said nutin a position radially spaced from the axis of saidshattsai-d.springactuated dog having aresilient vveclging action against portion of said bushing.

MARTIN L. ALBRECHT. J QHANN GEORGE BIRN.