US2076829A - Plurality clamping means - Google Patents

Description

April 13, 1937. G. E. SWARTZ PLURALITY CLAMPING MEANS I Filed Jan. 21 1955 2 Sheets-Sheet 1 INVENTOR 5212/6.

ATTORNEY P 1937- .G. E. SWARTZ PLURALITY CLAMPING MEANS 2 Sheets-Sheet 2 Filed Jan. 21, 1955 ATTORNI Patented Apr. 13, 1937 UNITED STATES FATE .1 T

1 Claim.

The present invention relates to clamping a plurality of work pieces with substantially the same clamping pressure by one clamping operation. In present day manufacture and quantity production, the prior art, in work clamping, has not kept in step with the speed of production and considerable time was lost by prior means and methods of work clamping.

The present invention aims to reduce the time required for work clamping by clamping a plurality of work pieces simultaneously and by one clamping operation.

Present day production requires that as many as possible work pieces be held for operation thereon and that the holding of all the work pieces is attained by one clamping operation and that each of the work pieces is held with substantially the same clamping pressure as the other 5, work pieces.

Objects of the present invention are:

To provide for efllcient, simultaneous holding of a number of work pieces, each with substantially the same holding or clamping pressure as Q5 each of the other Work pieces.

To provide compensation between work holding elements so that one compensates another for equalization of holding or clamping pressure among all of the work holding elements.

To provide resiliency for someof the work holding elements in the same device.

To provide automatically shifting shoes as a feature of equalization of the holding or clamping pressure.

To provide a clamping plate which eventually contacts all of the work pieces but first contacts the work pieces on the resilient work holding elements.

To provide an operating means to move the 410 clamping plate into and out of work holding or clamping positions.

To provide a releasable locking means to retain the work clamping plate in a position.

Other objects will be pointed out in this specification, or will become obvious or apparent, or will suggest themselves upon an inspection of this specification and the accompanying drawings.

In the accompanying drawings, forming part of this specification:

Fig. l is a vertical section taken longitudinally through the device and shows one type of device, embodying the present invention, for simultaneous clamping four bearing caps for drilling holes therethrough; the device is shown as having the clamping plate clamping the bearing caps and the eccentric mechanism on dead center to retain the clamping.

Fig. 2 is an end View of Fig. 1 partly in section to better show interior structure.

Fig. 3 is a plan View of Fig. 2 with the clamping plate removed.

7 Fig. 4 is a fragmental section taken on line 4-4 of Fig.1.

Fig. 5 is a fragmental section showing the bottom of one of the end ones of the work receiving elements.

Similar reference characters refer to similar parts throughout the views.

For simultaneous clamping of a number of work pieces, a single clamping member is used to clamp all of the work pieces thereon by a single clamping movement of the clamping member. This clamping member is to be moved upwardly Sllfficiently far to allow the difierent work pieces to be individually placed on the work receiving end of each of the work receiving elements and each work piece being located thereon. Springs are to normally hold the end ones of the work receiving elements up a little higher than the middle ones. The upward movement of the end ones of the work receiving elements being limited to allow room to insert the work pieces thereon below the clamping member. When work pieces are placed on the tops of the work receiving elements, the weights of thework pieces are transmitted to the work receiving elements and move the same vertically and thereby move shoes laterally and, 'the work receiving elements being guided to move only vertically, move the shoes laterally until all of the weights balance each other. The clamping member, upon downward movement thereof, is to first contact the end ones of the work pieces and move the same and the work receiving elements downwardly and, by that movement, move the shoes laterally and some of them vertically also for compensating of the clamping pressure. The vertically movable shoes to abut the ends of the middle ones of the work receiving elements and float laterally relative thereto. This vertical movement of some of the shoes in contact on the lower ends of work receiving elements moves these work receiving elements upwardly until the work pieces thereon contact the clamping member. A continuation of the downward movement of the clamping member thereafter exerts clamping pressure on all of the work pieces and clamps all of them simultaneously against the clamping member. When no springs are to be used, the weights of the work pieces shift the shoes laterally until the pressure is equalized. The clamping member, upon a downward movement thereof, first contacts the highest one or ones of the work pieces and moves the same downwardly and there: by moves the shoes compensatingly laterally. The remaining work pieces follow the same action. When all of the work pieces are moved downwardly until all of the shoes are in lateral contact and neither one can move further laterally, all of the work pieces now being in contact on the single clamping member, the pressure of the clamping member then firmly clamps the work pieces to the clamping member and puts the entire clamping mechanism into a locked-together condition 5 to be released by an upward movement of the clamping member.

The device shown in the accompanying drawings, illustrative of the present invention, shows a clamping device for holding four work pieces with 10 clamping pressure equalizing or compensating means to effect simultaneous clamping of all of the work pieces with equal pressure.

The base A, preferably substantially inclosed to store a quantity of lubricant in the bottom 15 thereof to continually lubricate the movable elements therein and to avoid the necessity of continually paying attention to lubrication of the elements therein and relieving an operator from the necessity of watching this lubrication and results 20 in better efiiciency of the device and of the operator.

The tubular bosses H], H, I02, and I03 extend upwardly from the base A to guide the below described work carrying elements.

The work clamping plate B is of one piece structure sufl'iciently long and wide to cover all of the work pieces which can be held in the device in one clamping. The round pieces H and I2 project from the respective ends of the plate B and each 30 has journaled thereon one of the eyebolts |3.

The structures which depend from each of the eyebolts are duplicates and description of one applies to the other also. Each of the eyebolts has the shank |4 externally threaded to the internal threads in one end of the turnbuckle IS. The stud I6 is fixed into the eccentric strap H and has the externally threaded end |8 threaded to the internal threads in the other end of the turnbuckle. The threads in the ends of the turn- 40 buckle are right and left hand respectively. The eccentric strap embraces the eccentric H! which is fixed on the shaft 20 to rotate therewith. The shaft 20 is journaled in the base and has the squared ends 20| for taking hold of the shaft for 45 rotation thereof.

The guide pins 2|, one for each work piece, have one end thereof fixed in the plate B and the other end projects downwardly and through and is guided in the bosses 2|| projecting sidewise 50 from the below described work receiving elements.

This structure maintains a specific relation between the clamping plate and the individual work receiving elements and prevents shifting of the parts.

The two posts 23 are fixed in the base and the clamping plate has two corresponding bores therethrough, fitting to the posts, so that the plate can slide on the posts, longitudinally thereof and is guided thereon in its movement toward and away from the base.

The work receiving element 24 has the shank 25, diametrically round for economy of manufacture, fitting slidably into the bore in the tubular boss l0, and has the head 26 to exchangeably 5 receive different kinds of adapters formed for different forms of work pieces. The end 28 of the guide pin 22 acts as a dowel pin to relate the different adapters to the head.

.. The spring 29 is inserted endwise into the lower end of the shank 25 and projects therefrom and extends to abutment on the wall 30 in the base. The screw 3| is threaded into the boss l0 and has the pilot 32 extending into the keyway 33 in the 75 shank 25. The keyway 33 has the end wall 34 to abut the pilot 32 and thereby limit the upward movement of the work receiving element 24 by the spring 29. The pilot may fit closely to both sides of the keyway so that this fit can be used to prevent rotative movement of the part 24. Normally, the guide pin 22 is quite sufficient to prevent rotative movement of the part or element 24. However, the pilot 32 may be used to prevent rotative movement of the element 24 when the guide pin is not used. The inclined face 35 is provided on the lower end of the shank 25 for purposes appearing presently.

The work receiving element 36 is mounted in the boss H13 and is of the same structure as the element 24 described above.

The work receiving element 31 is mounted in the boss |0| has the shank 38, also diametrically round for economy of manufacture, fitting slidably into the bore in the tubular boss I 0|, and has the head 39 and the adapter 21 thereon similar to and for the same purpose of the upper structure of the element 24 above described. The lower end of the shank 38 is flat.

The work receiving element 40 is mounted in the boss I02 and is of the same structure as is the element 3'! described above.

A row of main compensating shoes are slidably supported on the wall 30. Each shoe is an individual unit slidable laterally on the wall 30 and is spaced from adjacent shoes. The shoe 4| has the inclined face 42 on one side thereof and complementary to the inclined face 35 on the shank 25. The other side of the shoe 4| has the inclined face 43 of the same inclination as the face 42 and parallel therewith longitudinally.

The shoe 44 is of the same structure as the shoe 4! and the inclined face 45 thereon is complementary to the inclined face 35 on the shank of the element 36.

The shoes 46 and 41 are duplicates of each other and of the shoes 4| and 44.

A second row of intermediate shoes 48 and 49 are superimposed over the row of main shoes. Both sides of the shoe 48 have the inclined faces 50 and longitudinally parallel, and complementary to the inclined faces on the main shoes. The upper face 52 is flat. The shoe 49 is a duplicate of the shoe 48.

Operation The device shown and described is designed to simultaneously clamp four work pieces at one clamping. It is obvious that one could be designed to clamp more or less than the four pieces shown or to clamp differently formed work pieces.

The work pieces 53 are bearing caps and each is to have two holes drilled therethrough. The bushings 54, guiding the drills, are fixed in the clamping plate and the lugs 55, upstanding from the work holding elements, together with the lugs 56, depending from the clamping plate, cate the work pieces relative to the work holding elements and to the clamping plate and the drill guiding bushings therein.

Each work piece is first individually placed between the lugs of one of the adapters while the clamping plate is held in uppermost position by the dead center condition of the eccentric mechanism, opposite that shown in Fig. 2, which is caused by a rotative movement of the shaft.

When the four caps are placed into or onto the respective adapters, the operator removes his hands from under the clamping plate which is then held against reversing or self movement downwardly by the dead center condition of the eccentric mechanism.

A rotative movement of the shaft then. moves the clamping plate downwardly through the eccentric mechanism: and, eventually, into contact on the upper faces of all of the bearing caps and clamps the same into and onto the respective adapters for drilling of the holes.

While the clamping plate is in its uppermost position, the springs 29 hold the work receiving elements 24 and 36 and is limited in its uppermost positions which is determined by the pilot 3? abutting the upper wall of the keyway 33.

When the shaft is rotated for a work clamping operation, the clamping plate first contacts the end ones of the bearing caps and presses or moves the same downwardly and also moves both of the shanks axially downwardly and abuts the inclined faces on the ends of the shanks on the corresponding inclined faces on one side of the shoes M and il and thereby moves the shoes laterally on the wall 30.

This lateral movement of the shoes 4i and ti,

, relative to each other, contacts the inclined faces on the opposite side of the shoes: 'll and 4'! onto the corresponding inclined faces on the sides of the laterally movable shoes 48 and t9 and thereby tends to move upwardly the intermediate shanks 38 and 52 and the bearing caps supported thereon until the latter also contact the clamping plate. This action compensates and equalizes and distributes the clamping pressure substantially equally on all of the bearing caps. Difierent degrees of friction between contacting elements may cause this equalization to be substantial, or not quite even, but can. be remedied by so designing the contact faces so that the friction between the same is alike for all. This, however, is of no special import and adds to expense of manufacture and has not been found necessary in practice since the design of the inclined faces as shown provides sufiicient pressure equalization, herein called substantially, for practical purposes of work clamping.

When all of the bearing caps are in contact on the clamping plate, a final rotative pull on the shaft increases. the clamping pressure and effects clamping with a pressure equivalent to the rotative final pressure applied to the shaft.

The eccentric mechanism is again on dead centers when the work is clamped so that the clamping plate remains locked against self release when rotative pressure on the shaft is released.

The shaft is rotated in either direction for breaking the dead center condition of the eccentric mechanism and can also be rotated in either direction for bringing about work clamping and locking. When the shaft is rotated for work releasing, the dead center condition is first broken and the clamp-ing plate is moved upwardly until a dead center condition of the eccentric mechanism is again established and the clamping plate is held against self reversing until released by a rotative movement of the shaft.

In the structure shown and described, the axial pressure of the drills, due to drilling thereby, is transmitted axially to the work receiving elements which transmit the drilling pressure squarely to the wall 3%! of the casing and thereby eliminates all overhangs and spring of parts of the device and breaking of drills or spoiling of work when the drill points break through.

While work is being clamped by the clamping 75 plate moving downwardly, the plate first contacts the work pieces on the end ones of the row of work receiving elements and presses the same downwardly against the action of the springs 29 and contacts the inclined faces on the end ones of the work receiving elements either simultaneously or one after the other. The downward movement of the end ones of the work receiving elements moves the shoes ll and ll laterally on the wall and moves the shoes it and il laterally and thereby also moves the shoes 58 and 49 laterally and effects compensation among the shoes. As the clamping plate continues to move downward, the plate also contacts the work pieces on the middle ones of the work receiving elements, the lateral shifting of the shoes is continued, the middle ones of the Work receiving elements are moved axially by the lateral movement of the shoes through the co-operating inclined faces and the clamping pressure is distributed among all of the work pieces.

It has been found that, in simultaneous clamping of a plurality of work pieces, a decided advantage is attained when the clamping pressure is applied to one or two of the work pieces first and is then transmitted to a compensating means and to the other work pieces.

When the work pieces are fully clamped, as is seen in Fig. 1, the shoes 58 and 39 have moved the middle ones of the work receiving elements axially compensatingly while the end ones have been moved downwardly by the clamping plate and the shoes have effected equalization and distribution of the clamping pressure among all of the work pieces.

The device shown and described is economical of manufacture, efficient in operation, holds a number of work pieces simultaneously, distributes the clamping pressure substantially equally among all of the work pieces, and is self locking when either in work clamp-ing or in unclamping conditions.

It is quite obvious that the present invention can be applied to clamping means other than the one shown and described and that changes and modifications in structure and arrangement of parts thereof can be made within the scope and spirit and intent of the present invention and of the appended claim.

Therefore, without limiting the present invention to the application and structure as shown and described,

I claim:

A compensating means for simultaneously clamping a plurality of work pieces by one clamping movement, comprising, a plurality of individually movable work receiving elements guided to move only vertically, shoes movable only laterally, shoes movable laterally and vertically superimposed over the first mentioned shoes, co -operating bevel fa'ces between the contacting ones of said shoes, said superimposed shoes being in contact on the ends of the middle ones of said work receiving elements, the end ones of said work re ceiving elements being beveled to co-operate with the bevels on the end ones of the first mentioned shoes, a movable work clamping plate for engaging all of work pieces on said work receiving elements and operating the compensating means for simultaneous clamping of all of the work pieces, a spring normally tending to move the end ones of said work receiving elements upwardly, and a stop means for limiting the up and down movement of said end ones of the work receiving elements.

GUY E. SWARTZ.

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