US2342049A

US2342049A - Feed control mechanism

Info

Publication number: US2342049A
Application number: US461290A
Authority: US
Inventors: Nels T Holmbeck
Original assignee: Nels T Holmbeck
Priority date: 1942-10-08
Filing date: 1942-10-08
Publication date: 1944-02-15
Anticipated expiration: 1961-02-15

Description

Feb. 15,. 1944. N. 'r. HOLMBECK FEED CONTROL MECHANISM Filed Oct. 8, 1942 :5 Sheets- Sheet 1 HUGH-1 ZZZ-"1. lye-4s Humvee-ck."

N. 'r. HOLMBECK 2,342,049 FEEQOONTROL'MECHANISM Filed Oct. 8, 1942 3 Sheets-Sheet 3 v 3 k 7 ll i. .i. m

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Patented Feb. 15, 1944 UNITED STATES PATENT OFFICE 2,342,049 I FEED CONTROL MECHANISM Nels T. Holmbeck, Chicago, Ill. Application October 8, 1942, Serial N5. 461,290

8 Claims. gel. 164-22) My invention relates to a feed control mechanism adapted particularly for accurately controlling the feed of stock, such as a metal'strip orv band, to the cooperating members of die sets, punching assemblies, or the like.

My invention concerns particularly improvedv operation and control of stock feed mechanism which is permanently attached to and forms an integral part of a die set assembly, as for example in the arrangement disclosed in Dickerman Patent No. 1,968,479, dated July 31, 1934. In this type of feeding arrangement, a stationary gripper unit and a reciprocating gripper unit cooperate with the movement of the punch element of a die set to shift the stock band periodically the required feed distance into the die set and to hold it while the die operations are being performed. 'However, it has been found 'that, in feed structures of this type, there may be very slight overfeed, or underfeed, for each feeding operation, and although such error may be very slight for each feed movement, the error will be so multiplied during a period of operation of the die set that the incorrect feeding will result in imperfect die formation of the object to be formed out of the stock band.

The important object of my invention is therefore to provide simple means for correcting each feed movementof the stock band before operation of the :die set to work on the band. This I preferably accomplish by effecting release of both gripper units from the stock band just prior to final closing of the die elements and by providing an aligning member on the punch element for engagement with the freed band to shift it into proper position over the die element for final movement of the punch element into forming engagement with the stock band.

The purposes and advantages of my invention will be clearly understood from the structure shown on the drawings, in-which:

Figure 1 is a side elevation of the inlet end of a die set and the feed mechanism secured thereto; v

Figure 2 is a plan view of the feed mechanism; v Figure 3 is an enlarged section on plane IlI--III of Figure2, showing the position of the reciprocating gripper unit after a feeding operation;

Figure 4 is a similar section showing the gripper unit about to engage the stock band for feeding thereof; v

Figure 5 is a section on plane V-V Figures 2 and 3;

Figure 6 is a perspective view of one of the 55 ceivethe shaft 42 for the raisebars which function to release the gripper unitsfrom the band; and l Figure '7 is an enlarged cross-sectional view of the upper and lower feed rollers of the gripper 1 unit to show the clutch mechanism for permit ting rotation of=the rolls in only one direction.

The frame of the feed mechanism comprises inner and outer cross walls I!) and II, and front and rear side walls 12 and I3. Adjacent to the outer cross wall it is the stationary gripper assembly A. This assembly comprises the shaft I4 extending between and secured to the side walls l2 and I3 by caps l5 through which extend set screws l6 for holding the shaft against rotation. Extending between the side walls l2 and I3 and mounted on the shaft I4 is the lower feed r011 l1., u 1

At their upper ends the side walls 12- and it have the rectangular slots [8 respectively for the, rectangular bearing blocks l9 which receive thev ends of a shaft 20 on which is mounted the upper gripper roll 2| vwhich extends between the side walls [2 and l3. Set screws 22 hold the shaft against rotation in the bearing blocks.

Extending between the side walls [2 and 13 and across the upper ends of the slots I8 is a plate 23 which is detachably secured to the walls as by screws 24. This plate has upwardly extending opposed walls 25 and 26 thereon between which is located a pressure bar 21 which, at each end, has a threaded stud 28 extending therethroughin'alignment with the corresponding bearing block I9. The threaded studs at their lower ends terminate in abutment heads 23 between which and the bearing blocks I9 springs 30 are interposed.

Between the side walls 25 and 25 above the pressure bar, a cam lever 3| is secured to a fulcrum pin 32 journalled in the side walls, the cam lever having the cam head 33 which, upon downward swing of the lever, will force the pressure bar 21 downwardly for compression of the springs 30 and corresponding pressure against the shaft 20 to hold the upper roll 2| in pressure engagement with the lower roll l1. s

The reciprocating gripper unit B comprisesthe side walls 34 and 35 connected at their lower ends by cross bars 36 and these side walls are secured to front and rear guide or carriage frames 31 and 38, as by bolts 39. These guide frames 31 and 38 have guide channels 49 and 4|, respectively, therethrough for receiving the inner guide portions I2 and [3' of the side walls 12 and 13.

The side walls 34 and 35 at their lower ends relower gripper roll 43,

the shaft being locked against rotation by set screws 44. In their upper ends the side walls 34 and 35 have the rectangular slots 45 for the bearing blocks 45 which receive the shaft 4'! for the upper gripper roll 48, set screws 49 holding the shaft against rotation in the bearing block.

A plate 50 is detachably secured by screws to the side walls 34 and 35 over the tops of the slots 45, and between the side walls 52 and 53 on the plate is the pressure bar 5d having threaded studs 55 therethrough at its ends terminating in heads 56 between which and the respective blocks 46 are located the springs 51. is secured to the fulcrum pin 59 journalled in the side walls 52 and 53 and upon downward swing of- The cam lever 53 the lever the cam head 60 will shift the pressure bar downwardly for pressure exertion of the spring to hold the upper gripper roll 48 for'pressure engagement against the lower roll 43. -By

virtue of the threaded engagement of the studs 55 in the pressure bar 54 (Figure'5), and the the threaded engagement of the studs 28 in the pressure bar of the gripper unit A (Figure 1), the desired pressure engagement of the upper gripper rolls with the respective lower gripper rolls can be obtained. After setting of the studs they-are held in adjusted position by lock nuts 6 I.

The front and rear guide frames 31 and 33 for the reciprocating gripper unit 13 have abutment ears t2 and 63 thereon to which rods 64 and 65 are rigidly secured and to extend therefrom through passageways 66 in the ears 6! and 68 on the outer end wall I i. Between the opposed ears, the rods support compression springs 69'and l0, and the outer ends of the rods being threaded to receive adjusting and lock nuts H. The springs tend to hold the gripper unit B in its inner position with the nuts H abutting the ears 61 and 5B, and by means of the nuts H the feed travel of the unit B is determined.

The stock band S extends through the feed mechanism between the upper and lower rolls of the gripper units, the rolls of each unit having the central portion l2 of increased diameter and of less width than the band, the end portions 13- of the rolls being of lesser diameter so that the pressure of the springs against the supporting blocks for the shafts of the upper rolls will exert prssure against the band to hold it against the lower rolls.

Referring to Figure '7, each of the rolls is permitted to rotate only in one direction on its supporting shaft and is locked against rotation in the opposite direction. Any suitable looking or clutch means may be provided. As shown,

clutch balls M, urged by springs 15, will lock each upper roll against counterclockwise rotation but will permit clockwise rotation thereof, while the clutch mechanism in the lower rolls lock them against clockwise rotation but permit counterclockwise rotation. Thus, after a feed of the stock band, the rollers on the unit A will hold the hand against reverse movement, but the rolls on the unit B will roll along the band as the'supporting carriage "for the'rolls is shifted outwardly,

and then upon inward-or feeding movement'of the unit B, its rolls will clamp the band for feed thereof during inward movement of the carriage, the rollers of the unit A being then free to rotate.

Adjustably secured to the end wall ll of the feeder structure, are arms Tit journalling opposed guide rollers or spools l7 between which the incoming stock band S passes. On the innerrend wall l0 similar guide rolle'rsor spools 18 'are journalled between'which the band travels,

to the end walls l0 and H as by screws 54.

these spools tending to hold the band aligned on its passageway through the feeder units. To further guide the band and to hold it aligned with the gripper rolls, guide member I9 and 86 are provided. As shown, each guide member comprises upper and lower plates BI and 82 separated along their outer portions by a spacer plate 83, the upper and lower plates along their inner portions receiving between them the edge portions of the stock band, the spacer plates forming guides engaged by the edges of the stock band. These guide structures are secured at their ends AS indicated at 85, the guide members are cut away at their inner portions sufficiently to provide clearance for engagement with the band of the center portions 12 of the rolls I! and 21, and as indicated at '86, the guide members are cut out along their inner portions to provide clearance for engagement with the band of the center portions 72 of the rolls 43 and 48 as the unit B is reciprocated.

Referring to Figures 1 and 3, the die block 81 of adie set supports the various die structures D, and the punch block 83 supports the various punch structures P. The feed structure is secured to a supporting block 89 on the die block by means of screws 95 passing through the end The die set with the feed attachment thereon is placed on a punch press bed for cooperation of the punch press ram with the punch block 88 in a manner well understoodin the art.

At the upper innercorners of the guide frames 37 and 38 forthe feed unit 3 are journalled cam rollers 9! and .92 for enga ement by cam plates 93 and Q4 secured to and depending from the punch block .88. These cam plates are of rectangular cross section and each presents at its lower end the diagonally extending cam surface terminating in the vertical surface 96 at the inner edge of the .platesthe width of the plates at the surface-35 being equal to the distance of the desired feed of the stock hand. Above the surface .196 the. cam plates have the vertical surlower forward ends of the inclined cam surfaces 95 are in engagement with the cam rollers so that, upon downward movement of the punch block, the feed unit B willbe shifted outwardly until the vertical surfaces 96 receive the cam rollers. Such outward movement ofthe unit B is resisted by the springs 69 and 1B. Duringsuch outward movement of the unitB, the stock band will be held against outward movement by the rolls of the unit A-which are locked against rotational movement, the rolls of the unit B being however free to roll along the stock band. While the rollers are being engaged by thevertical surfaces 56, the-punch block 88 is moved down sufficiently for punching or forming work on the band. As the punch block 88 is then moved up-- wardly the vertical surfaces 96 will leave the cam rollers and the camrollers will come into engagement with the inclined cam surfaces 95 along which they will travel by the-pressure of the springs 69 and 10 until the unit B is restored to its inner-position. During such inward movement of the unit B, its rolls will be locked against rotation and will grip the stock band to feed it into the die set, the rolls on the unit A-being then free to rotate. After the feed operation both-sets of rolls will be locked against rotation .to prevent outward movement of the band from its fed-in position.

Although great precision is employed in mak ing and assembling the feed structure, very slight overfeed or underfeed may occur which, for a single feed operation, may not be material, but which, when multiplied after a period of operation of the die and feed structure, may cause error in the formation of the band by the die structures. I have therefore provided simple and eflicient means for compensating for any feed errors and assuring accurate and correct posi-' tioning of the band in the die structure before the punch or other forming members on the punch block come into engagement with the band and the die structures on the die block. This I accomplish by effecting release of the upper rolls of the feed units from the band at the end of the outward movement of the unit B, and providing aligning means on the punch block for cooperation with the released band to shift it into its proper position in the die set. As shown on Figure 1 I mount an aligning pin 98 in the punch block 88, which pin has a tapered end, and in the die structure adjacent to the feed mechanism L I provide a passageway 99 for the aligning pin. In advance of the aligning pin, the punch block carries a punch pin II!!! for cooperating with a die passageway IUI to punch out the stock band to provide pilot holes I92 for passage of the aligning pin into the passageway 99, so that the tapered end of the aligning pin may engage with the band edges around the holes I02 to shift the band, if necessary, to bring the holes I92 into alignment with the passageway 99 and thereby set the band in proper position for die operation.

The mechanism forreleasing the upper rolls from the band for operation of the aligning pin, is best shown on Figures 2, 3, 4 and 6. The releasing mechanism is in the form of raise bars Hi3, one of such bars being shown in perspective in Figure 6. The two bars are supported from the guide structures I9 and 89 in alignment with the cylindrical end portions I3 of the rolls in the units A and B, the ends I94 of the bars being of a height to extend between these end portions of the rolls when the upper rolls are clamped down against the stock band. The middle portions I95 of the bars are received in supporting and guide brackets I98 secured to and extending from the respective guide structures I9 and 80, with the outer end portions I04 of the bars extending between th outer portions 73 of the rolls of the unit A. Between its inner portion and its outer portion each bar has upwardly extending portions I99, the approaches I II! to these portions I95 being inclined, as clearly shown on Figure 6.

When the punch block 88 is in its upper position and the unit B is in its inner position as shown on Figures 1, 2 and 3, the rolls of the unit I B are displaced from the inner ends of the raise bars I93. When the unit B is shifted outwardly by the cam plates 93 and 94 upon downward movement of the punch block, the spaces between the outer portions I3 of the rolls on unit 13 will receive the outer ends I94 of the raise bars,'and when the cam rollers 9| and 92 are in engagement with the vertical surfaces 96 on the cam plates, the inclined surfaces III! at the inner ends of the raise bars will be engaged by the outer portions 13 on the upper roll of the unit B, and the inclined surfaces III! at the outer ends of the raise bars will be in engagement with the outer portions 13 of the upper roll of the unit A. Now, as the punch head is moved down further to engage the surfaces 91 of the cam plates with the cam rollers 9| and 92, the resulting final movement of the unit B toward the unit A will cause the inclined surfaces III! to wedge the upper rolls of the units upwardly against the pressure of their pressure bars to release the rolls from the stock band. This released position of the upper rolls is maintained while the vertical surfaces '91 on the cam plates remain in engagement with the cam rollers, and while the stock band is thus released, the aligning pin 98 will pass with its tapered end through the hole I92 in the band and will center this hole with the passageway 99 so that, if there was any error in the feeding of the band by the feed mechanism, such error will be compensated for and the band shifted into the proper position for engagement by the forming members on the punch block, the operation of the aligning pin taking place just before the punch pin I and other punch or forming members on the punch block come into engagement with the band and the cooperating die elements on the die block 81. The punch pin I09 then punches the hole in the stock band for cooperation with the aligning pin 98 after the next feed operation of the feed mechanism. Such feed takes place as the cam plates are withdrawn from the cam rollers as the punch block moves upwardly. As the punch block starts to move upwardly, the aligning pin 98 will remain in the hole I92 until the vertical cam surfaces 91 on the cam plates are withdrawn from the cam rollers on the unit B, the movement of the cam rollers from the surfaces 91 to the vertical surfaces 96 permitting the outer portions I3 of the upper roll of the unit B to leave the inclines I91 at the inner ends of raise bars so that the bars are free to be shifted inwardly by the pressure of the upper roll of the unit A against the outer inclines I01 on the bars, the pressure bars on the units A and B being then free to reset the upper rolls against the stock band for gripping of the band between the rolls of the unit B so that, as the cam rolls on the unit B come into engagement with the inclined cam surfaces on the cam plates, the springs 69 and I9 may shift the unit B to its inner position and to feed the clamped band into the die set. On the raise bars, the spaces between the projections I06 are sumciently longer than the width of the supporting brackets I98 so that the bars may have sufficient longitudinal movement to be shifted into wedging engagement with the upper rolls during the final outward movement of the unit B and to be freed from the rolls during inward or feeding movement of the unit B. When a new stock band is to be fed intothe structure, the punch head 89 is brought down until the surfaces 9'! 0n the cam plates will just come into engagement with the cam rollers on the unit B and before the punch pin I99 reaches its cooperating die element. The upper rolls of the units A and B being then raised, the end of the stock band can be fed in past the die passageway II but short of the passageway 99 forthe pin 99. Then upon final downward move ment of the punch block, the punch pin will punch in the band a hole I92, shown in dotted lines on Figure 2, and when the punch block is again raised and the unit B is shifted inwardly for feeding the band, this hole I92 will be brought into registration with the die passageway 99 for aligning cooperation with the pin 98 when the punch block is again brought down for outward movement of the unit B and raising of the upper rolls of the units from the band.

' I thus provide simple and efficient means in connection with feed mechanisms of the type described which will compensate for any feed errors and assure accurate alignment of the stock band in the die set before any die operation on the band. I do not however desire to be limited to the exact structure, arrangement and operation shown and described as changes and modification may be made without departing from the scope of the invention.

I claim as follows:

4 1. In a die set, cam means on one of the cooperating and relatively movable members of the set, a supporting frame secured to and extending longitudinally from the other of said members, a carriage movably mounted on said supporting frame and having a part for engagement by said cam means, stock gripper means on said carriage free to move relative to the stock upon outward movement of the carriage by said cam means, spring means for shifting said carriage inwardly upon release thereof from said cam means, said gripper means during movement of the carriage by said spring means being effective to grip the stock whereby the stock is fed into the die set, means effective during the final movement of said carriage by said cam means for entirely disconnecting said gripper means from the stock for free longitudinal movement thereof in either direction, and means on the die set for cooperating with the released stock to correct for any overfeed or underfeed thereof and to accurately align the stock in the die set just before the stock is worked on by the die set members.

2. In a die set, cam means on one of the cooperating and relatively movable members of the set, a supporting frame secured to and extending longitudinally from the other of said members, a carriage movably mounted on said supporting frame and having a part for engagement by said cam means, stock gripper means on said carriage free to move relative to the stock upon outward movement of the carriage by said cam means, spring means for shifting said carriage inwardly upon release thereof from said cam means, said gripper means during movement of the carriage by said spring means being effective to grip the stock whereby the stock is fed into the die set, means effective during the final movement of said carriage by said cam means for entirely disconnecting said gripper means from the stock for free longitudinal movement thereof in either direction, means on the die set for punching pilot holes in the stock, and alinging means on said die set cooperable with said pilot holes while the stock is free of the gripper means for compensating for any overfeed or underfeed by the gripper means and to properly align the stock in the die set before the stock is worked on by the die set members.

3. In a die set a supporting frame secured to and extending outwardly from one of the die set members, a gripper unit movable on said frame and having gripping means for gripping stock to be fed into the die set, cam means on the other member of the die set effective during closure movement of the die set members to shift said gripper unit outwardly for gripping engagement with the stock, said cam means being further effective to overshift said unit outwardly during the end part of closure movement of said die members, means effective during such overshift of said unit for entirely releasing the gripping means from the stock for free longitudinal movement thereof in either direction, and means effective during the fore part of the final movement of said die members toward each other for engaging with-the released stock to effect movement thereof to correct any overfeed or underfeed thereof by the gripper unit and to accurately align the stock in the die set members.

4. A die set having stock feed mechanism thereon in the form of a permanent attachment, means controlled by the closing and opening movements of the die set members for effecting operation of the feed mechanism to feed stock into the die set, means effective just before final closure movement of the die set members for entirely releasing the feed mechanism from the stock for free longitudinal movement thereof in either direction, and means on the die set members for cooperation with the released stock to correct any overfeed or underfeed of the feed mechanism and to correctly position the stock before engagement therewith of forming structure on the die set members.

5. A die set comprising members movable to open or closed position, feed mechanism forming a part of the die set, means controlled by the closing and opening movementof the die set members for controlling the feed mechanism to feed stock between the die set members, punch means for the die set members for punching pilot holes in the stock during closure movement of the members, means effective just before final closure movement of the die set members for effecting entire release of the feed mechanism from the stock for free longitudinal movement thereof in either direction, an aligning pin on one of the die set members and a passageway therefor in the other die set member, said pin just before finalclosing movement of the die set members being projected through one of the pilot holes and into said passageway for shifting the stock after release of the feeding mechanism therefrom whereby to correct for any overfeed or underfeed of the stock by the feeding mechanism and to accurately align the stock between the die set members before said members are finally moved to closed position.

6. A die assembly comprising a die block element and a punch block element, a supporting frame extending from the die block element, a stationary gripper unit on said supporting frame and a feeding gripper unit reciprocable on said frame, cam means on said punch block member engageable with said reciprocating unit to shift it outwardly upon closure movement of the die block and punch block members, spring means for shifting the reciprocating unit inwardly during opening movement of the die and punch block assemblies, an upper and a lower-gripper roll for each unit and spring means tending to urge said rolls together for clamping a stock band to be fed by the unit, said rolls being adapted to rotate in only one direction whereby the rolls on the stationary unit will hold the stock band against outward movement and the rolls on the reciprocating unit may roll along the band during outward movement of the unit and to grip the band during inward movement of the unit for feed of the band, means effective during the final outward movement of said reciprocating unit for entirely releasing the gripper rolls from the stock band for free longitudinal movement of the band in either direction, and coopcrating means on said die and punch block members for engagement with the released stock band to shift it for correction of any overfeed or underfeed by the feeding mechanism and to accurately align it for working engagement by die and punch structure on said die and punch block members.

7. A die assembly comprising a die block element and a punch block element, a supporting frame extending from the die block element, a stationary gripper unit on said supporting frame and a feeding gripper unit reciprocable on said frame, cam means on said punch block member engageable with said reciprocating unit to shift it outwardly upon closure movement of the die block and'punch block members, spring means for shifting the reciprocating unit inwardly during opening movement of the die and punch block assemblies, an upper and a lower gripper roll for each unit and spring means tending to urge said rolls together for clamping a stock band to be fed by the unit, said rolls being adapted to rotate in only one direction whereby the rolls on the stationary unit will hold the stock hand against outward movement and the rolls on the reciprocating unit may roll along the band during outward movement of the unit and to grip the band during inward movement of the unit for feed of the band, means effective during the final outward movement of said reciprocating unit for entirely disengaging the gripper rolls from the stock band to release the band for longitudinal movement in either direction, a punch pin on the punch block member for punching pilot holes in the stock band, a tapered aligning pin on the punch block member engageable in one of the pilot holes while said stock band is released and before engagement with the stock band of the punching pin for shifting the stock to correct any overfeed or underfeed by the feeding mechanism to properly align the stock between the die and punch block mem bers.

8. A die assembly comprising a die block element and a punch block element, a supporting frame secured to and extending outwardly from the die block element, a stationary gripper unit on said supporting frame and a reciprocating gripper unit on said frame, upper and lower gripper rolls for each unit between which a stock band is to be shifted for feeding between the die and punch block elements, yieldable clamping means engaging the upper rolls of the units for clamping of the stock band, the rolls of said units being capable of rotating in only one direction whereby the rolls of the stationary unitwill hold the stock band against outward movement and the rolls on the reciprocating unit may roll along the band during outward movement of the unit but will grip the band during inward movement of the unit, cam means on said punch block element having a cam surface engageable with the reciprocating unit to shift it outwardly along the stock band while the band is being held by the stationary unit, spring means for returning said reciprocating unit inwardly when said cam surface is being withdrawn therefrom, the movement of said reciprocating unit by said cam surface being equal to the desired distance of feed of the stock band, another cam surface on said cam means operative after movement of said reciprocating unit by said first mentioned cam surface to effect a slight further outward movement of said reciprocating unit, raise bars longitudinally movable on said supporting frame and having inclined surfaces at their ends for engagement with the upper rolls of the units to raise them entirely away from the stock band during such final outward movement of the reciprocating unit whereby the stock band will be entirely released from the units, a punch pin on said punch block element for punching pilot holes in the stock band, a tapered aligning pin on said punch block element spaced from said pilot punch pin a distance corresponding to the desired feed distance of the stock band, said aligning pin being engageable in a pilot hole in 1 the stock band while said stock band is held released from the feeder units for shifting of the stock band to correct any underfeed or overfeed by the shifting unit whereby to properly align the band for punching thereof by the pilot punch pin.

NELS T. HOLMBECK.