US2437200A - Clamping device - Google Patents

Description

I March 2, 1948, FQW. KUPPERSMITH CLAMPING DEVICE Filed Feb. 15, 1946 3 Sheets-Sheet 1 I III INVENTOR.

March 1943- F. '-w. KUPPERSMITH 2,437,200

' pmmrme DEVICE Filed Feb. 15, 1946 '3 Sheets-Sheet 2 March 2, 1948. F. w. KUPPERSMITH CLAMPING DEVICE Filed Feb. 15, 1946' '3 Sheets-Sheet 3 INVENTOR.

v BY

Patented Mar. 2, 1948 UNITED STATES PATENT OFFICE CLAMPING DEVICE Fred W. Kuppersmith, Bloomington, Ill.

Application February 15, 1946, Serial No. 647,926

My invention relates to clamping devices.

One of the objects of my invention is to provide an improved clamping device having a relatively quick take-up movement and means for holding the clamping jaws in clamping position when substantial resistance to movement of the movable jaw is encountered.

Further objects and advantages of the inven tion will be apparent from the description and claims.

In the drawings, in which several embodiments of my invention are shown,

Figure 1 is a plan view of a tool jig fixture embodying my improved clamping device;

Fig. 2 is an elevational view of Fig. 1;

Fig. 3 is a sectional view of the lower part of the fixture, substantially on the line 33 of Fig. 1, and is also substantially a cross-sectional view on the line 3-3 of Figs. 8 and 10;

Fig. 4 is a sectional view on the line 44 of i 3;

Fig. 5 is a sectional view on the line 5-5 of Fi 3;

Fig. 6 is a. sectional view on the line BB of Fig. 3;

Fig. '7 is a sectional view on the line 1 -'l of Fig. 3;

Fig. 8 is an elevational view of a vise embodying my invention; I

Fig. 9 is a section on the line 9-9 of Fig. 8, and

Fig. 10 is an elevational view showing another form of vise embodying my invention.

Referring to the drawings in detail, and first to Figs. 1-7, incl, the construction shown therein comprises a tool jig fixture having a base portion I provided with a face plate portion 2 which also serves as a clamping element, a jig plate element or jaw 3, to which leader pins 4 are secured slidably mounted in sleeves 5 extending upwardly from the base portion, a crankshaft 6 rotatably mounted in suitable bearings in the base plate, and a pair of pinions 8 formed on this shaft and meshing with rack teeth 9 on the leader pins. The upper clamping jig plate 3 may be provided with suitably positioned bushings I0 for positioning and guiding the drills.

When a piece of work is placed in the fixture, it is clamped in place by rotating the crankshaft 6 by means of the operating handle or crank H to cause the leader pins 4 to move downwardly and draw the upper plate 3 down .against the work. The construction is such that, when the upper plate 3 engages the work, thus ,arresting 8 Claims. (01. 192-8),

the downward movement of the leader pins 4 and .the rotation of thepinions 3, further motion of the crank which is swiveled on the crankshaft 8, will effect a clamping action which will bind the crankshaft against rotation, thus preventing the face plate 3 from releasing the work when the pressure on the crank is released. The construction provided for this purpo3e, shown in detail in Fig. 3, comprises in addition the shaft 6, pinions 8 and racks 9, a first friction face element l2 rotatable with the shaft and held against axial movement thereon by the pin l3, a second friction face element I4 held against rotation and axial movement and formed as an integral boss on the base I and engageable with said first friction face element 12 for holding the shaft 6 against rotation, a third friction face element [5 rotatable with the shaft and axially movable thereon, a fourth friction face element I6 held against rotation and axial movement and formed as an integral boss on the base and engageable with said third friction face element l5 for holding the shaft against rotation, compression spring means I! tending to separate said engageable friction face elements, and means for forcing the engageable friction face elements into engagement when the upper face plate or clamping jaw engages the work to prevent further movement of the leader pin racks 9 and of the shaft 6 carrying the pinions 8 which engage these racks.

The means for causing frictional engagement of the frictional face elements comprises a face plate cam construction including three hardened balls I8 rotatable in pockets E9 in the friction face element [5 and engaging arcuate recesses 20 in the face of the hub 2! of the crank arm or lever H which has a limited swiveling motion on the shaft. This hub 2! is held against axial movement on the shaft by means of anti-friction balls 22 bearing in the opposing raceways on the hub 2| and on the nut 23 which is screwed tightly into the end of the shaft 6.

The arcuate recesses 20 in the face of the hub 2| are tapering in depth, being deepest in the middle portion and tapering gradually toward the ends. With this construction movement of the hub 21 relative to the friction face element l5 from the medial position of the arcuate re cesses 20 with respect to the balls will cause the face of the hub to separate further from the opposing face of the friction face element. This will force the friction face on the element l2 into engagement with the friction face on the element l4 and will force the friction face of the element l5 into engagement with the friction face of the element I 6.

In order to hold the hub 2i so that the medial portion of the recesses 2i! will normally engage the balls, the coil compression spring I1 is provided, seated in an axial recess 24 in the shaft 6 and bearing at one end on a hardened ball 25 seated at the bottom of therecess and at its other end on a shoulder 26 on a screw 21 threaded in a nut 23 axially slidable in the recess 24 and keyed or splined to the shaft 6. The nut 23 is provided with a central opening 29 affording access to the head of this screw for adjusting the tension of the spring.

For holding the friction element i and the nut 28 against rotation with respect to the shaft 6 and still enabling relative axial movement of the nut and friction element, the nut'and fric-' tion element are provided with milled keyways Si; and Si and the tubular portion of the shaft is provided with slots 32 registering with these keyways, in which registering keyways and slots are seated the hardened circular disc keys 33. These disc keys 33 are engageable with the arcuate end of the milled keyways Eli and 3| to prevent relative axial movement of the nut 28 and friction element it beyond a certain distance in one direction.

In use, in clamping the work in the fixture, the initial take-up movement of the upper jaw is effected by the rotation of the crankshaft E, causing the pinions .8 acting on the racks 9 to pull the leader pins l carrying the upper jaw 3 downwardly until it engages and clamps the work. When the upper jaw engagesand clamps the work the shaft is prevented from further rotation. The, tension of the coil compression spring I! is sufilcient during this initial movement to press the hub 2| of the lever and the friction element it, which is splined to the shaft 6, toward each other to hold the medial portion of the recesses 2B in engagement with the balls l8, thus preventing any substantial relative rotation of the hub 2i and friction element l5 and avoiding any substantial frictional engagement between the friction faces of the friction ele ments. When the engagement of the upper jaw 3 with the work stops further rotation of the shaft 6, the machinist may continueto press the lever to effect a limited additional movement thereof, causing the hub 2! to rotate with respect to the friction element i5 to bring the shallower portions of the arcuate recesses 20 into engagement with the balls 18 and to further separate the hub 2i and friction element 15. In this separating movement, the nut 28 may slide in the axial recess 2% in the shaft -6 to enable the separating movement, this sliding movement of the nut being necessary because of the engagement of the circular disc keys 33withthe arcuate ends of the milled keyways.

As the hub 2i separates further from the friction element E5, the hub will exert endwise thrust on the ball race member 23 which isthreaded into the operating shaft 6. This end thrust acting on the shaft 6 will cause the friction face element [2 to be drawn snugly against the friction face element 14 and the cam pressure on the balls will cause the friction face element [5 to be pressed snugly against the friction face element I6. This will effectually lock the shaft against rotation when pressure on the operating lever is removed.

To release the clamping jaws the lever H is rotated in the direction opposite'to the clamping movement. This brings the medial portions of the arcuate recesses 2s again into engagement with the balls is allowing the friction faces to disengage whereupon, due to the action of the spring ll, further rotation of the operating lever will cause rotation of the operating shaft 6 and upward movement of the leader pins 4, releasing the upper clamping jaw 3 from engagement with the work.

The construction shown in Figs. 8 and 9 is in many respects similar to that just described. Figs. 8 and 9, however, show my invention embodied"in'a'vise. The construction shown comprises a base as having a fixed clamping jaw 35 and a movable clamping jaw 36 slidably mounted on the base 3% and operated in its sliding movement by means of a shaft 6 rotatably mounted on the'movable jaw 36, having a pinion portion s engaging a rack 3s secured to the middle portion of the base. The sliding jaw 3% is mounted on parallel guides fit at the sides of the base and held in position by means of gibs 4i secured to the sliding jaw. V

In operation, the work is placed on the table of the base and the crank is*operated to rotate the shaft having the pinion portion engaging the rack. This effects a quick'initial pick-up movement.

The construction shown in Fig. 10 is quite similar to that shown in Figs. 8 and 9. In this form, however, the sliding jaw is provided with an internally screw-threaded bore which is engaged'by a threaded portion 43 of the operating shaft 6. The parts shown in cross section in Fig. 3 'may be the same as the corresponding parts described in connection with Figs. 3 and 8. In use, rotation of the shaft effects a relative quick-closing movem'entof the jaw 12 with respectto the jaw 43 When the movable jaw 42 engages thework, further rotation of 1 the shaft 8 is prevented-and the final clamping action is effected by the lost-motion movement of the operating crank I i with respect to the shaftt.

As' previously indicated. Fig. 3- is substantially a cross section of the construction on the section lines 33'0f Figs. 1, 8-and l0. This construction has been described in connection with Fig. I and will now be described only in ageneral way in connection with Figs. 8 and 10. It comprises the handle ii, the friction face element i2 rotatable with the shaft 8, a second friction face element M engageable with the friction face element i2, a third friction face element i5 rotatable with the shaft,- a'fourth friction face element held against rotation, a compression spring I? tending to separate the friction face elements, hardened-balls ill engaging'the'arcuate'recesses 2t, anti-friction balls 22', screw 21, nut'23 and keys 33.

When the engagement of-the movable jaw (36 in Figs. 8' and 9 and 42in Fig. 10) with the work stops further rotation of the" shaft 6, the machinist may continue to press the lever to effect a limited additional movement thereof, causing the hub 22 to rotate with respect to the friction element l5 to bring the shallower portions of the arcuaterecesses 28 into engagement with the balls i B and to further separate the hub 21 i and friction element i5. In this separating movement,-the nu-t ZB-may. slide'in the axial recess 24 in the shafts-toenable the'separating movement.

As the hub 2i separates furtherfrom' the friction element- 1 5,: the huh willexertendwise thrust on the ball rest member :23. This end thrust will cause the friction fa'ce elements l2 and 1 tend the friction face elements 15 and IE to be drawn together to lock the shaft 6 against rotation.

' To release the clamping jaws, the lever II is rotated in a direction opposite to the clamping movement. This will cause rotation of the operating shaft 6, releasing the clamping jaw 35 from engagement with the work.

Further modifications will be apparent to those skilled in the art and it is desired, therefore, that the invention be limited only by the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for holding the shaft against rotation,

spring means tending to separate said engageable friction face elements, and actuating means for rotating said shaft when the friction face elements are not engaged and forcingthe engage able friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an'actuating element mounted on said shaft and having a limited rotation with respect thereto, and cam means acting when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable friction face elements into engagement.

2. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for holding the shaft against rotation, spring means tending to separate said engageable friction face elements, means for adjusting the tension of said spring means, and actuating means for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an actuating element mounted on said shaft and having a limited rotation with respect thereto, and cam means acting when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable friction face elements into engagement.

3. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for holding the shaft against rotation, spring means tending to separate said engageable friction face elements, and actuating means for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an actuating element mounted on said shaft having a limited rotation with respect thereto and held against axial movement thereon, and cam means acting between said actuating element and one of said axially movable friction face elements when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable friction face elements into engagement.

4. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element fo holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for' holding the shaft against rotation, spring means tending to separate said engageable friction face elements, and actuating means for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an actuating element mounted on said shaft having a limited rotation with respect thereto and held against axial movement thereon, and ball cam means acting between said actuating element and one of said axially movable friction face elements when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable friction face element into engagement.

5. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said. members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engagablewith said third friction face element for holding the shaft against rotation,

aasmoo helical spring means-coaxial with said shaft tending to separate said engageable friction face elements, and actuating means for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an actuating element mounted on said shaft and having a limited rotation with respect thereto, and cam means acting when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable friction face elements into engagement.

6. A clamping device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face elenientheld against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for holding the shaft against rotation, helical spring means coaxial with said shaft tending to separate said engageable friction face elements, and actuating means forrotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rota tion comprising an actuating element mounted on said shaft and havinga limited rotation with respect thereto, and cam means acting when the shaft encounters resistance and the acuating means are rotating with respect to said shaft to force'the engageable friction face elements into engagement, said shaft having a tubular portion in which said spring means are seated.

A claiiijiing device comprising two'relatitely adjustable members and means for effecting reiative adjustment of said members and holding them in adjusted position comprising ai'otatable shaft for" adjusting said members, a first f iction face element rotatable with said shaft and held against axial movement thereon, a second friction faceeieineht held against rotation andaxial movement engag'eable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotatable with respect thereto and axially movable thereon, a fourthfriction face element held against rotation axial movemerit and enga'geabie with said third friction face element for holding the shaft against rotation, helical spring means coaxial with said shaft tending to separate said cngageabl friction face elements, actuating means for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation coin-i'a'ri'sirig anac mating element mounted on said shaft having a limited rotation with respect thereto and held against axial mavenent thereon, cam means act'- ing between said actuating element and one of said axially movable friction face elements when the shaft encounters resistance and the actuating means are rotating with'resp'ect to "said shaft to force the engage'able friction fa'c'e' elements into engagement, said shaft having a tubular portion in which said spring means are seated and said tubular portion having a lateral opening and foice transrrlitting' ni'e'an's acting between said spring means and said axially movable element and extending through said lateral opening.

8. A clamping'device comprising two relatively adjustable members and means for effecting relative adjustment of said members and holding them in adjusted position comprising a rotatable shaft for adjusting said members, a first friction face element rotatable with said shaft and held against axial movement thereon, a second friction face element held against rotation and axial movement and engageable with said first friction element for holding the shaft against rotation, a third friction face element rotatable with said shaft, nonrotat'able with respect thereto and axially movable thereon, a fourth friction face element held against rotation and axial movement and engageable with said third friction face element for holding the shaft against rotation, helical sprin means coaxial with said shaft tending to separate said engageable friction faceelerncnt's, actuating means'for rotating said shaft when the friction face elements are not engaged and forcing the engageable friction face elements into engagement when the shaft encounters increased resistance to rotation comprising an actuating element mounted on said shaft having a limited rotation with respect thereto and held against axial movement thereon, cam means acting between said actuating element and one of said axially movable friction face-elements when the shaft encounters resistance and the actuating means are rotating with respect to said shaft to force the engageable-friction face elements into engagement, said shaft having a tubular portion in which said spring means are seated and said tubular portion having a lateral opening and force-transmitting means acting between said spring means and said axially movable element and extending through said lateral opening, said force-transmitting means being adjustable to vary the tension of the spring means; V

FRED 'W; KUPPER-SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,855,939 Collins Apr. 26, 1932 2,381,480 Albrecht et al. Augfll, 1945

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