US3400836A - Retracting clamp - Google Patents

Description

Sept. 10, 1968 A. BENDE RETRACTING CLAMP 2 Sheets-Sheet 1 Filed Dec. 28, 1966 INVENTOR.

ALBERT BE NDE ATTORNEY Sept. 10, 1968 A. BENDE RETRACTING CLAMP 2 Sheets-Sheet 2 Filed Dec. 28, 1966 INVENTOR. ALBERT BENDE ATTORNEY United States Patent ABSTRACT OF THE DISCLOSURE An apparatus for grasping, holding and transferring a work piece on a high speed production line. The clamp is biased to the closed position to prevent slippage of the work piece during transfer. Cam controls regulate the movement of the clamp from a folded or stored position to a grasping position and then close and open the clamp at the appropriate time in the cycle of the ap- Background of the invention This invention relates to work handling apparatus and more particularly to a cam actuated and controlled mechanical hand for holding an article and transferring the article along a production line from one station to the next in line. D

Many of the prior art clamps exerted a fixed gripping force on the article to be transferred which often marred the article. These previous clamps were generally set-up to handle one thickness of material. The retracting clarnp of this invention is designed to accommodate varying thicknesses of material by having spring biased clamp blocks that can be adjusted to accommodate different thickness of materials.

Most of the clamps were developed for pushing or pulling articles from the forming equipment while the present invention is adapted for side pick-up and transfer from station to station on a synchronized high speed production line.

Summary of the invention The apparatus of this invention is a retracting clamp that is movable from a retracted or stored position to an extended or working position by a cam block and cam plate combination. When in the working position further movement of the cam block will actuate the clamp for closing. On closing, the clamp is biased to resiliently hold the seized article by a spring means. The spring means may be adjusted to provide varying pressures, as needed by the clamp. The support for the clamp is synchronized for movement with the production line so that clamping action and movement of the work piece will flow smoothly from station to station.

Description of the drawings FIG. 1 is cross-sectional view of the novel retracting clamp in the closed or clamping position, with phantom lines illustrating the position of the clamp in open position.

FIG. 2 is a view, in the direction of the arrows substantially alOng the line 2-2 of FIG. 1, phantom lines are used to illustrate the clamp in the folded or retracted position.

Description of the preferred embodiment Referring now to the drawings, as seen in FIG. 1 and FIG. 2, the preferred embodiment of this retracting clamp, indicated generally by the numeral 10, includes a support member 12 which in this embodiment is a tube. The tube 12 may be fixed or movable between a receiving and delivering position, as desired.

A pair of opposed cam plates 14, 16 are secured on the support member 12 by a plurality of bolts 18 and lugs 19. A spacer member 20 is secured between the cam plates 14, 16 by a plurality of bolts 22. The spacer member 20 maintains the cam plates 14, 16 at the proper spaced interval for permitting reciprocating movement therebetween of a cam block 24.

A pair of rollers 26, 28 are secured to the cam block 24 for rollingly supporting the cam block for reciprocating movement as indicated by the arrow A-A. Each roller 26, 28 is journalled in a groove 30, 32 formed in the respective cam plates 14, 16 for guiding and supporting the cam block therebetween. A drive shaft 34 is secured to the cam block 24 by a pin or other suitable means for moving the cam block back and forth upon command. A cam driving groove 36 is formed in the cam block 24 for receiving a pair of rollers 38, 40 rotatably secured on a shaft 42 attached to a cam follower 44. The shaft 42 also rotatably supports a second set of rollers 46, 48 positioned in cam grooves 50, 52 of the respective cam plates 14, 16. Y

The cam follower 44 is slidably supported in a clamp support 54. The clamp support 54 in turn is slidably supported in a cross head 56 that has a pair of arms 58, 60 journalled in the respective bearing 62, 64 secured on cam plates 14, 16 by bolts 66 or other suitable means. The cross head 56 supports the clamp support 54 and cam follower 44 for longitudinal sliding motion and pivotal motion about the axis of the arms 58, 60.

The upper end of the cam follower 44 slidably contacts a clevis 68. The clevis 68 is resiliently connected to the cam follower 44 by a bolt 70 threadably secured in the cam follower 44 and bearing on a shoulder 72 of the clevis 68. The resilience is provided by a stack of Belleville washers 74 positioned about the bolt 70 and supported on an internal shoulder 76 of the cam follower 44 and bearing against the end 78 of clevis 68.

Each arm 80 and 82 of the clevis has a link 84, 86 with one end pivotally connected thereto. The other end of each link 84, 86 is connected to one of the respective clamp arms 88, 90 intermediate the ends of the clamp arms. One end of each clamp arm 88, 98 is pivotally connected to the upper end of the clamp support 54. To the other end of the respective clamp arms 88, 90 a clamp block '92 and 94 is secured by bolts 96 or other suitable means.

In operation, from the retracted position shown in phantom lines on FIG. 2, the cam block 24 is moved to the right by power means (not shown) acting through drive shaft 34. Such movement of the cam block 24 causes the rollers 26, 28 to be moved along the grooves 30, 32 and the rollers 38, 40 are rotated in place on the lower part of the cam driving groove 36 while the rollers 46, 48 move along the horizontal portions 50a, 52a of the cam grooves 50, 52. Such movement of the rollers pivots the cam follower 44, clamp support 54 and cross head 56 about the axis of the trunnions or arms 58, 60 to an upright position. When the rollers 38, 40 reach the right end of horizontal portions 50a, 52a, the rollers 38, 40 begin moving up the slope of the cam driving groove 36 and the rollers 46, 48 move up the vertical portions 50b, 52b of the respective cam grooves 50, 52 to the position shown in solid lines in FIG. 2. The rollers 38, 40 are shown at their extreme vertical position, and have moved out of the cam driving groove 36 where they are positioned on a horizontal cam locking surface 37. During such vertical movement, the cam follower 44 is moved vertically relative to the clamp support 54 and cross head 56. The cross head 56 is secured from vertical movement by the bearings 62, 64, and the clamp support 54 is restrained from upward movement by retention ring 98 3 positioned in a groove at its lower end that bears against the cross head 56.'

With the clamp support 54 restrained from vertical movement, the upward movement of the cam follower 44 and clevis 68 give movement to the clamp arms 88, 90 through links 84, 86, causing the clamp arms to swing from the phantom line position of FIG. 1 to the solid line position so that the clamp blocks 92, 94 contact and grip the article or work piece .100. By varying the number of Belleville washers 74 or pressure on a coil spring, that could be substituted for the Belleville washers, the clamping force on the article 10% can be varied as desired.

To open the' clamp blocks and return the clamp to the retracted or stored position, the cam block 24 is moved to the left, as viewed in phantom lines of FIG. 2. During the initial movement, the rollers 26, 28 move to the left in grooves 30, 32 and the rollers 38, 46 move down the slope of the cam driving groove 36 while the rollers 46, 48 are moved down the vertical portions 50b, 52b of the cam grooves 50, 52. The clamp support 54 is prevented from moving with the cam follower 44 and clevis 68 by the lower edge thereof contacting the upper surfaces 102, 104 of the clamp block 24. Thus the relative vertical movement of the clevis 68 to the clamp holder, acting through the links 84, 86 opens the clamp blocks 92, 94 from contact with the work piece 100. Horizontal movement of the rollers 46, 48 in the horizontal portions 50a, 52a pivots the entire clamp to the retracted position.

Under instrumented test conditions the retracting clamp has been found to achieve accurate transfer of work pieces in a press transfer line at four to five times the speeds of otlher clamping devices achieving such transfer at accelerations several times the acceleration of gravity.

While but one embodiment of this invention has been described and illustrated, it is obvious to one skilled in the art that parts can be modified within the scope of the following claims.

I claim:

1. A work handling apparatus for grasping and transporting an article including a movable support member having a receiving position and a delivery position and being movable therebetween, and power source for moving said support member between said positions; a clamp hand movably secured on said support member for movement therewith, said clamp hand having a retracted posi tion and a working position and being movable therebetween, said clamp hand including cam means for moving said clamp hand between said positions, said cam means includes a cam plate having a guiding groove thereon, said actuating means including follower means interconnected between said linkage means and said guiding groove, a cam :block connected to said follower means and to said power means for moving said follower means as said cam block is moved by said power means on comrnand, a pair of clamp blocks having an open position and a closed position for grasping an article and being movable therebetween, linkage means \for moving said clarnp blocks between said positions, and actuating means connected between said cam means and said linkage means for moving said clamp blocks between said open and closed positions by movement of said cam means and power means for moving said cam means on command.

2. The apparatus as claimed in claim 1 wherein said actuating means includes a clevis pivotally connected to said linkage means, said follower means operably connected to said clevis for moving said clevis and said linkage means as said cam block moves said follower means.

3. The'apparatus as claimed in claim 1 wherein a clamp support is pivotally secured on said cam plate, said clamp support slidably supporting said follower means, said linkage means having a pair of first links with one end of each pivotally supported on said clamp support, a clamp block secured on the other end of each first link, and a pair of second links with one end of each pivotally connected intermediate the ends of one of said first links and the other end of each of said second links being pivotally connected to said follower means for moving said linkage when said cam block moves said follower means, whereby said clamp blocks are moved between said open and closed positions by movement of said cam block.

4. A work handling apparatus for grasping and transferring an article including a support member having a receiving position and a release position and being movable therebetween, a clamp hand mounted on said support member for movement therewith, said clamp hand having a working position and a stored position and being movable therebetween, said clamp hand including a cam plate having cam surfaces, a cam block operably contacting said cam plate and being reciprocally transversely movable relative thereto, a cam follower operably contacting said cam plate for following said cam surfaces thereon, said cam follower operably contacting said cam block for being moved on said cam surfaces by reciprocal movement of said cam block, support means slidably and pivotally supporting said cam follower on said support member, an actuating clevis connected to said cam follower for movement therewith, a clamp support slidably supported by said support means, a pair of clamp blocks pivotally supported on said clamp support, a pivotal connection pivotally securing each of said clamp blocks to said clamp support, said clamp blocks having a clamping position in close proximity to each other and an open position, said clamping blocks being movable about said pivotal connections between said positions, link means connecting said actuating clevis with said clamp blocks for moving said clamp blocks between said positions when said actuating clevis is moved relative to said clamp support by movement of said cam block whereby said cam follower and said actuating clevis are moved relative to said clamp support; and drive means for moving said support member between said positions and for moving said cam block upon command.

5. The apparatus as claimed in claim 1 wherein said cam block further includes a cam locking surface for locking said clamp hand in a receiving position.

6. A work handling apparatus for grasping and transporting an article including a movable support member having a receiving and a delivering position and being movable there-between, and a power source for moving said support member between said positions; a clamp hand movably secured on said support member for movement therewith, said clamp hand having a retracted position and an extended working position and being movable therebetween, said clamp hand including a cooperating pair of clamp blocks having a closed position for grasping the article and an open position for releasing the article and being movable therebetween; and a cam means having a cam groove and a cam follower for movement in said cam groove as said cam means is actuated, said cam follower being operably connected to said clamp hand for moving said clamp hand between said retracted position and said working position and for moving said clamp blocks between said open position and said closed position when said clamp hand is in said working position as said cam means is actuated; and power means for actuating said cam means upon command.

7. The work handling apparatus as claimed in claim 6 wherein said cam groove includes a first groove portion for controlling movement of said cam follower -for moving said clamp hand between said retracted position and said Working position by movement of said cam follower therealong, one end of said first groove portion having said cam follower therein for positioning said clamp hand in said working position and the other end of said first groove portion having said cam follower therein for positioning said clamp hand in said retracted position, and a second groove portion extending from said one end of said first groove portion for controlling movement of said cam follower for moving said clamp blocks between said open position and said closed position by movement of said cam follower therealong, said clamp blocks being in said open position when said cam follower is in the end of said second groove portion adjacent said first groove portion and said clamp block's being in said closed position when said cam follower is in said second groove portion at a position most remote from said first groove portion.

8. The work handling apparatus as claimed in claim 7 wherein said clamp hand includes a clamp support pivotally supported on said support member and operably connected to said cam follower for pivotally moving said clamp hand between said retracted position and said working position upon movement of said cam follower in said first groove portion, linkage means pivotally connected to said clamp support, and said linkage means having said clamp blocks secured thereto for movement therewith.

9. The work handling apparatus as claimed in claim 8 wherein said clamp hand includes a clevis resiliently connected to said cam follower for longitudinal movement therewith when said clamp hand is in the working position and pivotally connected to said linkage means for moving said linkage means when moved by said cam follower whereby the clamp blocks are moved between their open and closed positions when the clamp hand is in the working position and the clevis is moved by movement of the cam follower in the second groove portion.

References Cited UNITED STATES PATENTS 656,190 8/1900 Holcombe 2941 15 2,259,728 10/1941 Bridges 214-1 3,240,603 3/1966 Richards 214-1 GERALD M. FORLENZA, Primary Examiner. G. F. ABRAHAM, Assistant Examiner.

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