US3493159A - Strip roll feeder - Google Patents

Description

Feb. 3, 1970 v. J. BAYLUNAS, JR, ET AL 3,493,159

STRIP ROLL FEEDER 'Fil'e'd Dec. 15, 1967 5 Sheets-Sheet l INVENTORS. HERBERT G. LEIS Y, VINCENT J. BALU NAS IR DAVID B. EDWARDS Mew, 744% 2 Body ATTORNEYS Feb. 3, 1970 v. J. BALUNAS, JR., ET AL 3,493,159

STRIP ROLL FEEDER 5 Sheets-Sheet 2 Filed Dec. 15, 196'? NVENTORS. LEI SY ATTORNEYS Feb. 3, 1970 v. J. BALUNAS, JR. ET AL 3,493,159

STRIP ROLL FEEDER 5 Sheets-Sheet 3 Filed Dec. 15, 196'? INVENTORS. HERBER-T e. LEISY, VINCENT J. BALUNAS,JR DAVID B. EDWARDS Meqez, 7M8 Bod ATTORNEYS Feb. 3, 1970 v. J. BALuNAs. JR, ETAL 1 3,493,159

STRIP ROLL FEEDER FIG.8

.INVENTORS. HERBERT G. LEISY,

VINCENT J. BALUNAS IR. I08 52 DAVID B. EDWARDS Mew, 714% 8 Eady AT TORNIEYS Feb. 3, 1970 v. J. BALUNAS, JR, E1; AL 3,493,159

STRIP ROLL FEEDER Filed Dec. 15, 1967 5 Sheets-Sheet 5 21s Fl 6- 9 'INVENT HERBERT G. LEIS VINCENT a. BALUNASJR. DAVID B. EDWARDS Maya, 7' 61 @014; A r TORNEYS United States Patent Office 3,493,159 Patented Feb. 3, 1970 U.S. Cl. 226142 10 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a mechanism for feeding sheet metal strip stock into devices which consume precise quantities of the stock in a step-by-step fashion, as exemplified by power presses, punches, etc. In particular, this disclosure relates to a roll-type feeding mechanism for feeding strip stock into a press and which includes a pair of opposed strip feeding rolls driven by the press connecting rod in timed relationship with the press. A device for accurately feeding the strip between the rolls is provided by an oscillating micro-adjust arm connected between the press connecting rod and an oscillating roll lever that drives the rolls through a feed and return stroke. The length of the arm is varied to thereby vary the feed of the rolls during a feed stroke and the arm also rotates a cam shaft which has cams for disengaging the rolls near the end of a feed stroke and in timed relationship to the working cycle of the press.

This invention is particularly applicable to the feeding of strip metal stock into a metal working die press, punch, or other such similar device, and it will be described with particular reference thereto; however, it will be appre ciated that the invention has more general application. For example, the device may be used for feeding any strip material into a device which requires precise quantities of the material in a step-by-step fashion.

In the use of presses or other strip material utilizing devices, some type of feeder mechanism is usually provided for feeding the strip material into and out of the press or device. The feeder mechanisms are of many specific types but most of them have jaws or rollers between which the strip is intermittently clamped or pinched and advanced in predetermined increments into or out of the press. After each advance the strip material usually remains stationary while it is being worked upon. For example in a press it is often held stationary above a die block while a shape is being punched out of the strip by means of a ram. In power presses having a crankshaft driving the ram through a first crank, the feeder mechanism is usually operated by a supplemental crank on the crankshaft. The angular relationship between the cranks is such that the strip material is advanced while the ram is in the upper part of its stroke.

In some of the prior devices the strip material is fed intermittently, but the rolls feeding the material to the press do not release their grip at the end of the feed stroke. The strip material, therefore, cannot be easily positioned with reference to the dies and the strip is not entirely free to shift properly during the working stroke of the press.

It is also important that each increment of advance of the strip stock be of such length as to present a sufficient area of stock between the punch and die of the press to provide for a complete shape. Any excess in the length of stock, however, is waste which increases the cost. of producing the shapes. Since slippage between the strip material and the rolls would result in an improper increment of strip material, it is important that slippage be kept to a minimum.

In order to solve the above problem of positioning the strip material, it has become common practice to open the rolls at the end of a feed stroke by providing a roll feed mechanism in which an arm is connected between the press ram and the feed mechanism. The arm functions to open the rolls on the downward stroke of the ram just before the ram contacts the strip. This method of opening the rolls produces high shock loads on the roll feed frame and the supports because the arm is moving at its maximum speed when it opens the rolls. The high shock loads require large, heavy devices, increase the noise level of the machine and require more frequent repair of the roll opening mechanism.

Although there are many devices which provide for adjustment of the length of the feed stroke of the strip material, these devices are not entirely adequate because they do not provide for an accurate feed adjustment of the rolls while the press is in operation, and do not provide for sufficient variation in the length of strip material to be fed during each feed stroke. Also, the devices for adjustment of the feed are often provided as a separate mechanism from the device used for opening the rolls at the end of the feed stroke.

The present invention contemplates the overcoming of these problems by providing a feed roll mechanism for feeding strip material in a press, wherein an arm, connected between an oscillating connecting rod of the press and a roll lever driving the feed rolls, functions to actuate a cam mechanism for smoothly opening the feed rolls during the upward travel of the connecting rod. Incorporated in the arm is a device for fine adjustment of the throw of the roll lever while the press is in operation. Slippage between the feed rolls and the strip material is reduced by coating one of the rolls with a resilient material of appreciable thickness to develop a large coefficient of friction between the rolls and the strip material thus insuring an accurate feed to the press.

In accordance with the invention there is provided a mechanism for fine adjustment of the feed movement of a feed roll that feeds strip material. The feed roll is driven by a variable throw roll lever which is driven by an OS- cillating feed drive lever. Feed movement of the feed roll is varied by changing the throw of the roll lever. The mechanism to accomplish this variation comprises an arm connected between the roll lever and the feed drive and pivoted about a fixed fulcrum intermediate the roll lever and the feed drive, thus, dividing the arm into a driving section and a driven section. The arm consists of a first link piece fixed on one end to the feed drive and a second link piece to which the first link piece is adjustably connected. The second link piece is connected to the roll lever and to the fulcrum and is adapted for adjustably moving the first link piece relative to the second link piece. This varies the length of the driving section and varies the resultant feed movement of the feed roll.

In accordance with a more specific aspect of this invention there is provided a roll feed mechanism of the type described wherein improved mechanism is provided for disengaging the rolls at the end of the feed cycle. This mechanism comprises springs normally urging the rolls into feed engagement during the feed cycle, a lifter for moving the rolls out of strip engagement, and a cam connected to the feed roll drive for actuating the lifter near the end of a feed stroke. v

The primary object of this invention is the PIOVlSlOl'l of roll feed mechanism having improved means for varying the length of strip material fed during each feed stroke.

Another object is the provision of a roll feed device having improved means for disengaging the rolls near the end of the feed stroke.

Another object of this invention is to provide a roll feed device having a mechanism for opening the rolls near the end of the strip feeding stroke in a smooth and shockfree motion.

Yet another object of this invention is the provision of a roll feed device having an improved mechanism for adjusting the length of the roll feed stroke while the roll feed is operating.

These and other objects and advantages will become apparent from the following description used to illustrate a preferred embodiment of the invention as read in connection with the accompanying drawings in which:

FIGURE 1 is a right side elevational view of the improved roll feed;

FIGURE 2 is a fragmentary end view of FIGURE 1 and showing details of the roll lift mechanism;

FIGURE 3 is a cross-sectional view taken generally along line 33 of FIGURE 1;

FIGURE 4 is a partial view taken generally along the line 44 of FIGURE 3 and shows details of the cam actuated roll lift mechanism;

FIGURE 5 is a top plan view of the roll feed;

FIGURE 6 is a left side elevational view of FIGURE 5, and shows details of the micro-adjust arm;

FIGURE 7 is a view of the micro-adjust arm taken generally along line '77 of FIGURE 6;

FIGURE 8 is a fragmentary view taken generally along line 88 of FIGURE 6;

FIGURE 9 is an elevational view taken generally along line 99 of FIGURE 6; and

FIGURES 10-12 are detail views of the cam actuator showing it in various positions during operation.

Referring now to the drawings wherein the showings are for the purpose of illustrating the preferred embodiment of the invention only and not for the purpose of limiting same, the main components of the invention will be first described generally in their order of operation.

GENERAL DESCRIPTION As best shown in FIGURE 6, the operation of the strip roll feeder starts with an input stroke from a press crank shaft, not shown, to the connecting rod 10. The connecting rod provides an oscillating feed drive and swings a micro-adjuslt crank arm generally indicated at 12. The micro-adjust crank arm 12 rotates a roll lever 14 and is pivoted about a cam shaft 16 which acts as a fulcrum for the arm, thereby feeding the bottom feed roll 18 through an overrunning clutch 20. Strip material X is engaged between the bottom feed roll 18 and a top feed roll 24 and is fed therebetween in the direction of the arrows to a press or other such device. As shown in FIG- URE 6, when the connecting rod 10 is oscillating in a generally upward direction the arm 12 will pivot in a counterclockwise direction about cam shaft 16 and cause the roll lever 14 to move in a counterclockwise direction, as indicated by the dashed arrows. In a similar fashion, a downward oscillation of arm 12 will impart a clockwise rotation to roll lever 14. The counterclockwise rotation of roll lever 14 corresponds to a feed stroke whereas the clockwise rotation of the roll lever 14 corresponds to a return stroke.

The connecting rod is drivingly connected in a conventional fashion to the same press crankshaft which is driving a press ram, not shown. The driving connection between the connecting rod 10 and the press ram is related so that when the rolls are imparting a feed stroke to the strip material the press ram is out of contact with the strip, but during the return stroke when the rolls are not feeding the strip material the press ram works on the strip material. The top feed roll 24 is driven simultaneously with the lower roll through a gear train generally indicated at 26. Roll 24 is held in position through compression springs 28 acting on top roller bearing blocks 29.

Referring to FIGURE 3, it is seen that the micro-adjust arm 12 not only imparts a driving motion to the feed rolls, but it also provides a rotary motion to the cam shaft 16 for lifting the top feed roll 24 from engagement with the bottom feed roll 18 at a predetermined time in the feed stroke. This is accomplished by cam plates 30 connected to a cam spacer 32 which is driven by the-cam shaft 16. Lift cams 36 actuate cam followers 38 that are carried by lift links 40. As is apparent, upward movement of links 40 results in movement of the top feed roll away from engagement with the strip material X.

On the return stroke of the press roll lever 14 is retated back to its starting position, as shown in FIGURE 6, however, the bottom feed roll 18 does not rotate back with the roll lever. This is accomplished by the overrunning clutch 20 which disengages the shaft of the feed roll on the return stroke and the backstopping effect of the overrunning clutch 42 which is also engaged on the return stroke. A friction brake 44 stops the bottom feed roll 18 at the end of the feed stroke, thereby allowing for the proper increment of the strip material to be fed between the rolls to the metal working press at the proper time.

MICRO-ADJUST ARM Referring now specifically to FIGURES 6 through 8 for the details of the micro-adjust arm 12, it is seen that the arm is formed from two relatively adjustable link pieces 46 and 47. As shown, link piece 46 is adjustably connected to link piece 47 through clamp screws 48 which slide in slots 49 to allow for relative movement between the link pieces. Link piece 46 has a cut out portion for receiving cam shaft 16 and for allowing relative sliding movement between the cam shaft and the link piece 46. The relative movement of the first link piece 46 is provided by an adjusting knob 50 that rotates a worm 52 which in turn by an adjusting knob 50 that rotates a worm 52 which is turn meshes with a worm wheel 54. The worm wheel 54 is connected by bolts 57 to a pinion 56 which drives a pinion rack 58 integrally mounted on link 46. As is apparent, rotation of the adjusting knob 50 turns the worm 52 rotate Worm wheel 54 and the pinion 56, and, consequently, to move the pinion rack 58 and a link 46 to provide the desired adjusted position. The worm wheel 54 and pinion 56 are mounted on cam shaft 16 which, through a coupling 60 shown in FIGURE 3, provides the movement for the disengagement of the top roll and is bolted to the housing by bolts 62.

The micro-adjust arm 12 is connected to the connecting rod 10 by a nut 80, stud 82, and a yoke piece 84 through which passes a yoke axle 86 that has a threaded section upon which a nut 88 provides engagement between a spacer portion 90 of 84 and the first link piece 46. The second link piece 47 is connected to the roll lever 14 through a roller 94 that rides in a groove 116 of the roll lever. The roller 94 is mounted on a shaft 97 which passes through link piece 47 and is bolted thereto by a nut 96. Second link piece 47 has integral therewith a collar 98 that fits over the cam shaft 16 and is connected integrally therewith through the use of a key 100 and a set screw 102.

The worm 52 is held in place on a mounting plate '104 by hearing blocks 108 and the worm wheel 54 rotates independently of the cant shaft 16- through the use of an axle 110', sleeve 112, and a wheel bushing 114. The roll lever 14 is provided with a longitudinally-extending driven link portion 118 which merges into a driving flange 120 that is mounted by a plurality of bolts 122 to a driver clutch plate 124.

As is apparent, the main purpose of the micro-adjust arm 12 is to provide a variable feed for the roll 20 by varying the throw, shown generally as dotted lines in FIGURE 6, of the roll lever 14. To provide this variable feed adjustment the clamp screws 48 are loosened with a wrench, then the adjusting knob 50 is turned either to advance or decrease the stroke.

The connecting rod which provides the oscillating drive for the arm '12 moves a given fixed, vertical direction during each feed and return stroke. In order to vary the throw of the roll lever 14, the distance between the centerline of the axle 86 and the centerline of the cam shaft 16, as best shown in FIGURE 7, is adjusted by the above-described movement of the worm wheel with the bolts 48 loosened. Since connecting rod 10 moves a fixed distance during each cycle, it can be appreciated by reference to basic fulcrum principles that the shorter the driving section between the centerline of 88 and 16 the greater the throw of the roll lever 14 and the greater the driving section distance the less will be the throw of the roll level 14. An increase in the throw of roll level 14 obviously increases the feed of the strip material fed therebetween and vice versa.

ROLL DRIVE Referring specifically to FIGURE 9'for the details of the drive roll arrangement, the oscillating roll lever 14 is shown being driven by the second link piece 47 of the micro-adjust arm 12. The oscillations of roll lever 14 drive a conventional overrunning clutch that is connected to a driver clutch plate 124 by bolts 122. The clutch housing 126 is welded to the end support plate 128 of the roll feed.

As shown, the clutch 20 drives lower roll drive shaft 130. The shaft 130 is positively connected to the roll in any convenient manner such as a keyway 136 and key 138. The backstopping clutch 42 is connected to the right end of shaft 130 and has its casing 126 welded to the second endplate 142.

The previously mentioned gear train 26, which interconnects the rolls consists of a gear 152 keyed to the shaft 130 through key 146. Gear 152 engages a pinion 154 that is mounted upon the upper roll shaft 156 by a key 158 and an end cap 159. A spacer 160 separates pinion 154 from the top roll bearing block 29.

FIGURES l and 9 show details of the brake 44 which is keyed to feed roll shaft 130 by a key 146. The brake includes a brake lining 150, and lower and upper brake bands 145 and 148 which are pivotally connected by a stud 147 and a nut 149. Adjustment of brake lining 150 is provided by a stud 151 and spring 153. As shown in FIGURE 5, the stud 151 is secured to the endplate 142 through a block 157 and spacers 155.

ROLL LIFT The description of the mechanism utilized for lifting the upper roll 24 will be made with a special reference to FIGURES 1-3. As shown, when the lift cams 36 lift the cam followers 38, the lift links 40 are actuated by their respective follower links 162 connected thereto by bolts 163. A return spring 164 is connected to the lift link 40 by a pin 166 on one end and by a pin 167 to the plate 168 on the other end. The upper feed roll shaft 156 is carried by the lift links 40. Consequently, vertical oscillation of the lift links 40, as shown in FIGURE 2, functions to move the top feed roll 20 out of engagement with the strip material X at the end of a feed stroke.

In FIGURE 2 at the top and bottom. feed rolls 24 and 18 are shown out of engagement. Between follower link 162 and upper feed roll shaft 156 there is provided in the lift link 40 a slot 174 in which rides a shaft 176 bolted on both ends by nuts 178. As shown in FIGURE 3, the shaft 176 is connected to a throw link 180 by a sleeve 181. The throw link 180 is in turn connected to an eccentric shaft 182. A lift lever 184, used for manual rotation of the eccentric shaft 182, is connected to the shaft through a key 188 and set screw 190. By lifting upward on lift leyer 184 the eccentric shaft 182, through the throw link 180 and the sleeve 181, will pull upwards on shaft 176 thereby providing a camming action to the lift link 40. This results in a lifting of upper roll shaft 156 and, consequently, a disengagement of the bottom and top feed rolls.

Referring to FIGURE 5, each of the lift links 40 are shown as suitably spaced from one another by a spacer shaft 196 extending therebetween. Bolts 192 are mounted on stud extensions 194 of the spacer shaft 196. The ends of the lift link 40 furthest removed from the cam-lifting mechanism are pivotally mounted in endplates 128 and 142 by the use of spacers 198, trunnions 200 and bushings 202. Threaded end section 203 of the trunnions 200 have nuts 204 for engaging the bushing 202 against the respective structural plates 128 and 142.

The follower links 162 are adjustable by the use of stop screws 210 and adjusting nuts 211 carried on plate 208 (see in FIGURES 2 and 5). Plates 208 are mounted on brace pieces 212, better shown in FIGURE 5.

The hold-down assembly for the upper feed roll is best shown in FIGURES l, 6 and 9 and comprises a pair of longitudinally extending braces 216 each having a circular portion 217 for holding the eccentric shaft 182. The compression force of springs 28 on the bearing blocks 29 is varied through the use of an adjusting screw 220 that passes through a locknut 222 and the brace 216 and has a spring retainer 224. Hold down bolts 218 bolt into extension pieces 226 of the endplate 128.

CAM MECHANISM FOR ROLL LIFT The details of the cam mechanism utilized for raising the link 40 will be discussed with special reference to FIGURES 24 and 10-12. As shown, the cam shaft 16 is connected by a key 236 to the cam spacer 32 which has opposed flanges 238. Flanges 238 are connected through bolts 240 to the cam plates 30. Each lift cam 36 is of generally cylindrical configuration having on one end thereof a cam 244 with a cam face 246 which is adapted for raising the associated carn follower 38 of the lift mechanism. The cam plate 30 has a cam plate foot 248 which has a leading face 249 and a trailing face 251, 251 being shown in FIGURE 4. The leading face 249 of the cam plate foot 248 is adapted to engage the lift cam foot 250 and especially the leading face 253 of the lift cam foot, as shown in FIGURE 4. The trailing face 251 of the cam plate foot is adapted for engagement with the trailing face 255 of the lift cam foot 250. A plate 252, shown in FIGURE 3, assures that the cam plate 30 on either side will rotate in unison so that both of the followers 38 will be lifted at the same time during the cycle.

In the present arrangement, the spacing of the leading face 249 of cam plate 30 from the leading face 253 of lift cam 36 is such that engagement therebetween and hence the raising of the top feed roll does not occur until the last few degrees of movement of cam shaft 16 in the feed stroke or counterclockwise direction. By this arrangement, the engagement of the cam face 246 with cam follower 38 being just as connecting rod 10 is approaching the top dead center point of its oscillation in the upward direction and is, therefore, moving at a comparatively slow speed. Therefore, the actuation of the cam follower 38 at this point results in a very smooth and shock-free opening of the rolls. In a similar manner, the cam follower 38 is adjusted to drop off of the cam face 246 when the connecting rod 10 is approaching bottom dead center during the last few degrees of cam shaft rotation in the return stroke or clockwise direction.

In operation the lift mechanism works as follows: as the cam shaft 16 is rotated in the counterclockwise direction, as viewed in FIGURE 4, which direction of rotation corresponds to the feed stroke of the rolls, the cam plate 30 also rotates. The cam plate food 284 protrudes into the path of the lift cam 36 and, therefore, during the last few degrees of rotation the cam plate foot engages the lift cam foot 250. The engagement is between the leading face 249 of the cam plate and the leading face 253 of the lift cam 26. This engagement rotates the lift cam 36 causing cam face 246 to raise cam follower 38 thereby opening the top feed roll at the end of the feed stroke. On the return stroke, which is the clockwise direction, as viewed in FIGURES 4 and 6, the top feed roll is held up and away from the strip during most of the return stroke since the lift cam 36 is left engaged with cam face 246. This arrangement is due to the fact that there is a lost motion connection between the cam plate 30 and the lift cam 36. At the end of the return stroke, the lift cam 36 is disengaged from the lift linkage when the trailing face 251 of the cam plate foot 248 engages the trailing face 255 of the lift cam 250, as better shown in FIGURE 4. This engagement causes the cam 244 to rotate allowing the follower 38 to drop off of the cam face 246, thereby allowing engagement of the upper and top feed rolls with the work strip X for the next feed stroke.

ADJUSTMENTS OF ROLL FEED In order to load and supply strip stock into the roll feed, the lift lever 184 is turned in the up position, as shown in FIGURE 3, and since the lever is connected to the eccentric shaft 182 causes a camming action through throw link 180. As best shown in FIGURE 2, the movement of shaft 176 in the slot 174 pulls up the throw link 40 and thereby pulls up the upper feed roll shaft 156 causing the roll disengagement. The strip stock X can then be passed through the rollers to the die set on the press. After the strip stock is in place, the guide rollers 171 are adjusted according to the width of the strip stock X through the use of guideways 254, as best shown in FIG- URE 5. Next, a scraper bar 260 is adjusted to the bottom side of the strip stock. The cam plate 30 is adjusted to give the correct lift for the chosen stock feed length. This adjustment is accomplished by removing bolts 240 that connect the cam spacer 32 with cam plate 30 and rotating cam spacer 32 in the desired direction. As viewed in FIGURE 4, rotation of the cam spacer 30 in the counterclockwise direction would cause actuation of the lift cam 36 sooner in the feed stroke direction of rotation. This is, of course, due to the fact that the leading face 249 of the cam spacer 30 is more closely spaced from the leading face 253 of the lift cam 36 when cam spacer 30 is thus rotated. The top feed roll lift linkage is adjusted so that the cam follower 38 on the adjusting lift link just touches the cam 244 after the lift lever 184 has been turned to close the top feed roll 24 on the strip stock. The lift lever 184 is closed, the crankshaft for the press mechanism is started, and the feed of the strip stock is actuated by the movement of the connecting rod 10 through the microadjust arm 12 which rotates or oscillates the roll lever 14 through the overrunning clutch 20 driving the bottom roll shaft 130, as previously discussed. If the amount of strip material X being fed between the rolls is insufficient, or excessive, the micro-adjusting arm 12 is used through the adjusting knob 50 to increase or decrease the amount of strip material being fed through the rolls to the die press.

Having thus described my invention, I claim:

1. A mechanism for fine adjustment of the feed movement of a feed roll for feeding strip material, said feed roll being driven by an oscillating feed drive and a roll lever having a variable throw for driving the feed roll, the improvement comprising: means to vary said throw and including an adjusting arm connected between the roll lever and the feed drive, said arm being pivoted about a fixed fulcrum intermediate the roll lever and the feed drive thereby dividing said arm into a driving section between the feed drive and the fulcrum and a driven section between the fulcrum and the roll lever, said arm including a first link piece fixed on one end to said feed drive, a second link piece to which said first link piece is adjustably connected, said second link piece being connected to the roll lever and to the fulcrum and means to adjustably move the first link piece in relation to the second link piece thereby varying the length of said driving section and the resultant feed movement of the feed roll.

2. The mechanism according to claim 1 wherein the means to adjustably move said first link piece comprises a rack connected to said first link piece and gear means for driving said rack.

3. The mechanism of claim 2 wherein the gear means comprises a pinion during the rack, a worm wheel driving the pinion and a hand-manipulated worm for driving the worm wheel.

4. The mechanism of claim 1 wherein said means to vary the throw also includes a slot in said roll lever and means for adjustably connecting said second link piece to said roll lever in said slot.

5. The mechanism of claim 1 wherein said fulcrum is a rotating shaft, and means responsive to the rotation of said shaft disengages the feed of said strip material.

6. In combination, a roll feed mechanism for feeding strip material comprising at least one set of rolls for feed engagement of the strip material fed therebetween, means driving said rolls through a predetermined feed stroke to thereby feed a predetermined length of strip material therethrough, a feed drive, an arm connected on one end to said feed drive and on the other end to said roll driving means, means actuated by said arm for disengaging the rolls out of feed engagement near the end of said feed stroke and means for varying the length of said arm to thereby vary the feed stroke, said arm being pivoted about a fixed fulcrum thereby dividing the arm into a driving section between the feed drive and the fulcrum and a driven section between the fulcrum and the roll lever, and the arm including two link pieces adapted for movement relative to one another to thereby vary the length of said arm.

7. The combination of claim 6 wherein at least one of said rolls is coated with a relatively thick layer of resilient material for increasing the frictional properties between the strip material and the rolls.

8. The combination of claim 6 wherein the fulcrum is a cam shaft rotated by said arm, and the roll disengaging means are actuated by the rotation of said cam shaft.

9. In a roll feed mechanism for feeding strip material into a strip with a working device that consumes precise quantities of strip material in a stepwise fashion, said mechanism including at least one set of rolls spaced for feed engagement of strip material fed therebetween, oscillating feed means driving said rolls through a predetermined feed stroke to thereby feed a predetermined length of strip material therethrough and driven by said strip working device in timed relationship therewith, the improvement comprising an apparatus for disengaging the roll engagement with the strip material near the end of said feed stroke, said apparatus including means urging the rolls into feed engagement during a major portion of said feed stroke, lift means for feed disengagement of the feed rolls and cam means connected to the oscillating feed means for actuating said lift means near the end of a feed stroke and in timed relationship with said strip working device, said cam means comprising an oscillating cam shaft connected to said oscillating feed means having feed and return stroke, a cam plate rotatably driven by said cam shaft and having leading and trailing faces, a lift cam with leading and trailing faces, said cam plate being mounted in spaced relationship to said lift cam so that the leading face of said cam plate engages the leading face of said lift cam near the end of the feed stroke thereby actuating said lift .means for disengagement of the rolls and so that the trailing face of said cam plate engages the trailing face of said lift cam near the end of the return stroke thereby providing a lost motion actuation of said lift means.

10. The mechanism according to claim 9 including a hand-actuated lever connected to the lift means for allowing manual disengagement of the rolls.

9/1943 Giffen 226-154 6/1958 Burman 226-154 X M. HENSON WOOD, JR., Primary Examiner R. A. SCHACHER, Assistant Examiner US. Cl. X.R.

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