US2287689A - Tie-plate punch - Google Patents

Description

June 23, 1942. w, F. LONGFIELD' 7 2,287,689

TIE PLATE PUNCH Filed Aug. 2, 1940 7 Sheets-Sheet 1 way 1?. Flow/754 June23, 1942. w. F. LOIQGFIELD TIE PLATE PUNCH Filed Aug. 2, 1940 7 Sheets-Sheet 2 June 23, .1942. w. F. LONGFI ELD 2,287,689

' TIE PLATE PUNCH Filed Aug. 2, 1940 7 Sheets-Sheet 3 INVENTOR 1; u/w El ONGF/ELD ATTORNEY June 23, 1942. w. F. LONGFIELD 2,287,689

TIE PLATE PUNCH v Filed Aug. 2', 1940 7 Sheets-Sheet 4 Fig 4 z Z/AZ/z&

ATTORNEY June 23, 1942.

w. F. LONGFIELD TIE PLATE PUNCH Filed Aug. 2, 1940 7 Sheets-Sheet 5 NVENTOR v LIA/IELO/VGF/ELD I BY W I ATTORNEY June-23, 1942. w LQNGFIE LD 2,287,689

- TIE PLATE PUNCH Y Filed Aug. 2, 1940 7 Sheets-Sheet 6 INVENTOVR v W/L LIA/1 ELOMSF/ELD ATTORNEY June 23, 1942.

. w. F. LoNGFiELb TIE PLATE PUNCH Filed Aug. 2, 1940 v 7 Sheets-Sheet- 7 INVENTOR 64' I, v i I I Fl Q 7 Patented June 23, 1942 UNITED STATES .A

' OFFICE TIE-PLATE PUNCH Application August 2, 1940, Serial No. 349,872

v 13 Claims.

This invention relates generally to punching and shearing machines, and more specifically to that type of machine generally known as tieplate punches.

In making tie-plates the stock is fed to the machine in long strips where it is punched,- and sheared 01f to the proper size by the machine. It is necessary to have a blank holder to grip the stock while it is being punched and t hold the stock until after the punches have been Withdrawn from the stock. Various different sizes and designs of tie-plates can be made by the same machine by changing the dies and punches in accordance with the particular design of tieplate being made. V a

The principal object of the invention is the provision with a machine of this character of a novel and efiicient blank holder which is operated by the main slide of the machine in time relation thereto.

Another object of the invention is the provision with a machine of this character of a blank holder mechanism which will exert a certain predetermined pressure on the stock and one which will engage the stock in advance of the punches and will hold it until after the punches have been withdrawn.

Another object of the invention is the provision with a machine of this character of a blank holder and operating mechanism therefor which is so constructed and arranged that the blank holder may be raised above its normal position so as to increase the die space to facilitate changing of dies.

Another object of the invention is the provision with a machine of this character of a blank holder and operating mechanism therefor which is so constructed and arranged that the blank holder may be moved below its normal position to facilitate the removal of punches from the slide.

Another object of the invention is the provision with a machine of this character of a blank holder and operating mechanism therefor that is so constructed and arranged that the blank holder may be readily raised or lowered above or below its normal position so as to facilitate changing of dies and punches.

Another object of the invention is the provision with a machine of this character of a blank 5,;

holder and operating mechanism therefor so con structed and arranged that the blank holder can be readily removed from the machine as desired.

Another object of the invention is the provision of a blank holder mechanism so constructed and arranged that differentforms of the stock gripping portion of the blank holder mechanism can be readily interchanged.

Another object of the invention is the provision with a machine of this character of a blank holder operating mechanism so constructed and arranged that it will yield in case an unusually large piece of stock is inserted in the machine, or in case of an overlapping of the stock,.which will eliminate any breaking of the mechanism under these conditions.

Another object of the invention is the provi-.

sion of a blank holder and operating mechanism therefor which is so constructed and arranged that it will adapt itself to various thicknesses of stock without the necessity. of adjusting the mechanism for any particular size of stock.

Other and more limited objects of the invention will be apparent from the following specification and. drawings forming a part thereof, wherein:

Figure l is a side elevation with a tie plate punch embodying my invention.

Figure 2 is a front elevation thereof.

' Figure 3 is a top plan view thereof.

Figure A is a sectional side elevation showing the parts in the. position that they assume when the slide is in its lowermost position, that is, at the end or": the punching and cutting stroke.

Figure 5 is an enlarged partial side elevation with parts broken away, showing the various parts in the position they assume when the blank holderis raised above its normal position so as to increase the die space to facilitate the removal of the die.

Figure 6 is an enlarged partial side elevation showing the various parts in the position they assume when the blank holder has been forced below the position it normally assumes when the slide is in its uppermost position so as to facilitate the removal and replacement of punches.

Figure '7 is a transverse section taken in the plane indicated by the line 7-1 on Figure l.

Figure 8 is a horizontal section taken substantially onthe line 8-8 of Figure 1.

Figure 9 is a perspective View of the stock from which the tie plates are formed.

Describing the invention by the use of reference characters, numeral l indicates generally a frame which has a cut out portion 2 at the forward end thereof. .A die supporting base 3 is cast integral with the frame adjacent to the lower end of the cut out portion 2 and a guideway 4 is formed in the frame above the cut out portion 2 and in alignment with the die supporting base 3. A slide is mounted for reciprocation in the guideway 4 and is held therein by a cover plate 6. The slide 5 is reciprocated by an eccentric I formed on the forward end of a shaft 8, and a driving link 9 which is operatively mounted in a cut out portion I!) in the slide 5.

The shaft 8 is rotated by a motor II which drives a pulley l2. The pulley I2 in turn drives a fly-wheel l3 through a plurality of belts l4. The fly-wheel I3 is secured to a shaft I5 which has a pinion gear l8 secured to the opposite end thereof. The pulley I6 meshes with and drives a gear I! which is keyed to a shaft I8 journaled in suitable bearings. The shaft l8 also has keyed thereto a small pinion gear l9 which meshes with and drives a large bull gear 28 which is loosely mounted on the shaft 8. The gear is operatively connected with the shaft 8 by a clutch mechanism H which is operated to clutch the gear 28 to the shaft 8 by a treadle 22 and suitable connections 23. The clutch 2| may be of any standard construction of which numerous designs equally efficient are available. When the clutch 2| is engaged to clutch the shaft 8 to the gear 20 the shaft 8 will be rotated through one revolution and then the clutch will be disengaged by a throw-out mechanism generally indicated by numeral 24 which is also of standard construction. In view of the fact that the clutch and the clutch operating mechanism are of standard construction and that any one of a number of different types of mechanisms of this character are available, and since they per se form no part of this invention, they have not been illustrated or described in detail. From the foregoing it will be apparent that when the operator depresses the pedal 22, the shaft 8 through the reduction mechanism just described, will be rotated through one revolution and then stopped. This, of course, will reciprocate the slide 5 from the position shown in Figure 1 down to its lowermost position as shown at Figure 4 and back to the position shown in Figure 1 where it is stopped with the parts in position for the next cycle.

The die supporting base 3 has suitably secured thereto a die 25 and the slide 5 has suitably secured to the lower end thereof a tool holder 26 which carries punches or tools 21. In operation a long strip of pre-formed stock 3|, such as illustrated in Figure 9, is fed into the machine from the right, as viewed in Figure 2, above the die 25 until it comes into engagement with an adjustable stop 28 carried on a bracket 29 secured to the frame I. When the stock is in position the machine is started by depressing the treadle 22. This will reciprocate the slide 5 as has been hereinbefore explained. The downward movement of the slide 5 will operate mechanism to be hereinafter explained, which will bring a blank holder generally indicated by the numeral 30 into engagement with the upper face of the stock 3! and clamp it firmly against the die 25 with a certain definite predetermined pressure. This clamping of the stock by the blank holder 39 against the die 25 is accomplished before the punches 21 come into engagement with the stock, so that the stock is firmly held during the punch operation. The slide 5 also has secured to the lower end thereof a shear blade 32 which cooperates with a stationary shear blade 33 secured to the base 2 as will be seen in Figure 2. The punches 21 are positioned in advance of the shears 32-43. From this it will be apparent that a tie plate is punched on one stroke of the as indicated at 53.

press and is sheared off to its proper width on another stroke of the press. It will also be apparent, since the punches 21 and shear blade 32 are reciprocated in unison that a complete finished tie plate will be formed on each stroke of the slide 5. 'During the first two to four strokes after a new strip of stock 3| has been inserted in the machine a gauge is inserted between the stop 28 and the forward end of the stock 3!. The gauge and the number of times it is used is dependent on the size and design of tie-plate being formed.

The numeral 34 indicates a counter balance cylinder for the slide 5 which is connected thereto through suitable linkage 35, and bell crank 35.

This is a standard air counter-balance mechanism such as is used in various different metal working machines and forms no part of this invention.

The blank holder 30 and the operating mechanism therefor will now be described. The blank holder per se consists of a transverse member 36 having an arcuate groove 31 therein, a transverse member 38 having an arcuate groove 39 therein, and a plurality of bars 40 extending between the members 35 and 38 in spaced relation to each other as most clearly shown in Figure 8. These bars 40 have their ends shaped to conform to the grooves 31 and 39 so that they may be received therein. Spacers 4| and rods 42 properly position the bars 40 in the grooves 31 and 39. These bars 40 must be positioned that they will firmly grip the stock and. must be so spaced from each other that the tool holder 26 and tools 21 may be reciprocated between the bars 40 down to and into engagement with the stock so as to punch the proper holes therein. The various different tie plates are of different dimensions and have different spacing of the spike holes, which makes it necessary that the bars 48, punch holder 26 and die 25 can be removed and adjusted for various different types of tie plates.

A pair of rods 43 are secured to th member 35. as indicated at 44, one rod being secured adjacent to each end of the member 36. These rods 43 extend upwardly through suitable guiding bores 45 in the frame I, and are pivotally connected at their upper end, as indicated at 46, to a pair of levers 41, one rod 43 being connected to each lever 41. The member 38 has a depending arm 48 cast integral therewith at each end thereof. The lower end of each arm 48 is pivotally connected, as indicated at 49, to one end of a lever 50 which is pivoted in a slot 5| in the base 2, A pair of spaced parallel upwardly extended bolts 54 are pivotally secured, as indicated at 55, to a pair of brackets 56 formed integral with and on the upper face of the slide 5. A cross-head 51 is slideably mounted on the bolts 54 and can move freely between the upper fiat surface 58 on eyes 59 formed on the lower end of the bolts 54 and nuts 60 threaded on the upper ends thereof. The forward ends of the levers 41 are pivotally connected to the ends of the cross-head 51 as indicated at 6!. The rearward ends of these lovers 4'! are each connected to the upper ends of a pair of rods 62 which are rigidly secured at their lower ends to plates 63 (Figure 7). Each of these plates 83 have secured thereto a pair of upwardly eX- tending piston rods 84, each of which carries a piston '65 on its upper end. These pistons 65 are mounted for reciprocation in a pair of cylinders 66 which are formed in a casting 61 (Figures 4 and 5). Cylinder heads 68, through which the piston rods 54 extend, close the lower edge of the cylinders 66. Each of the castings 6'! is Socured to the upper end of one of a pair of rods 59 which have their lower ends pivotally connect-ed as at 10, to the rear end of one of the levers 50, one rod 69 being secured to each lever 50. The numeral 1| indicates a turnbuckle in each of the rods 69, which is placed there so that the various parts canbe properly adjusted.

Compressed air, from any suitable source, is admitted to cylinders 66, either above or below the pistons 65 as is desired through pipes 12 and is controlled by a three-way valve 13.

Each of the levers 4'! carries a roller (4 rotatably mounted on a stud 15 secured to lever 4'! which works in an elongated slot 16 in the upper end of a link 11 which has its lower end pivotally secured as at 18 to a bracket 19 formed on the frame I.

Each rod 43 has a transverse slot 80 therein intermediate its ends Which receives one end of a lever BI which is pivoted at 82 to a bracket 83, which is formed on the frame I. The other end of the lever 81 bears against the head 84 of a screw 85 which is adjustably connected to a piston 86, which is mounted for reciprocation in a cyl inder 81. Each of the cylinders 8'! are bolted to the frame I. Compressed air, from any suitable source, is admitted to the cylinders 81 through pipes B8 and is controlled by a valve 88a.

The operation of the press will now be described with reference to Figures 1 and 4. After each operation the various parts are in the position shown in Figure 1 and naturallyafter each operation they return to this position before the 1 next operation is initiated. The pistons 65 are in the position shown in dotted lines in Figure 4 and air is admitted under pressure to the cylinders 55 above the pistons 65, and the cylinders 66 beneath the pistonsfiE are vented to the atmosphere through the three-way valve 13. The stock is placed in position with one end thereof in engagement with the stop 28. The treadle 22 is depressed which clutches the gear 20 to the shaft 8 and thereby rotates the shaft 8, which in turn will reciprocate the slide through one cycle. As the slide 5 moves downwardly, the lower faces of the nuts 50 on the rods 54 will engage the cross-head 51 and from there on the cross-head 5'! will move downwardly with the slide 5. The downward movement of the crosshead 57 will rock the levers 41 above pivots formed by the rollers 14 on the studs 15 engaging the lower ends of the elongated slots 16 in the links H. levers 4'! upward towards the position shown in Figure l. The forward ends of the levers 41 will naturally move downward with the cross-head 51. The downward movement of the forward ends of the levers ll will depress the rods 43 and consequently the members 35 and the ends of the bars 40 adjacent to the members 36 until the bars 40 come into engagement with the stock 3!. At the same time the upward movement of the rear ends of the levers 41 will pull the rear ends of the levers 5B upwardly through the rods 52, cross-head 63, piston rods 64, pistons 65, cylinder casting 61 and rods 69. This upward movement of the rear ends of the levers 59 will cause a downward movement of the forward ends of the levers 5|], which in turn will move the member 2133 and the ends of the bars 40 adjacent thereto downwardly until these ends of the bars 49 are also in engagement with the stock 3|. At this point the pivot for the levers 41 will change to This will move the rear end of the the pivotal connection between the upper ends of the rods 43 and the levers 41 as shown in Figure 4. The continued downward movement of the cross-head 51 will cause the forward end of the levers 4! to continue their downward movement and the rear ends thereof to continue their upward movement. The pistons 65 will then be moved by this further rocking movement of the levers 41 from the position shown in dotted lines in Figure 4 to the position shown in full lines in Figure 4. This is due to the fact that the blank holder bars 40 have been first moved into engagement with the stock 3| and consequently can move no further. This engagement between the bars and the stock 3| takes place before the punches 21 have been brought into engagement with the stock 3| which is, of course, before the slide 5 has reached its lowermost position. Consequently, some elastic means must be provided which Will stretch or elongate after the blank holder has come into engagement with the stock so as to allow the slide 5 to complete its downward movement and thus punch and shear the stock. The mechanism for operating the blank holder serves a two-fold purpose: First, it provides means for operating the blank holder by the movement of the slide in such a manner that the blank holder engages the stock before the slide has completed its downward movement, and then dwells during the rest of the downward movement of the slide; and second, it provides means whereby the blank holder will grip the stock with a certain predetermined pressure which is dependent upon air pressure in the cylinders 66 above the pistons 65 therein; On the upward movement of the slide 5 the blank holder will remain in engagement with the stock until the pistons "65 return from the full line position in Figure 4 to the dotted line position therein, and the various parts will return to the position shown in Figure 1 as the slide 5 completes its upward movement.

The primary purpose of the link 8|, cylinder 8! and piston 86 is to maintain the parts in the position shown in Figure 1. If some such means is not provided, the excessive weight of the cylinder casting 61, pistons 65 and various connecting rods and links which connect the levers 41 and 5!] together, together with the weight of the rear ends of these levers would cause these parts to drop downwardly and the various parts connected to the other ends of the levers 4! and to move upwardly until the cross-head 51 came into engagement with the nuts 60, which would throw the mechanism out of time, as it is necessary that the slide 5 be moved downwardly a short distance before starting the operation of the blank holder mechanism.

Another purpose of the lever 8!, cylinder 81 and piston 86 and connecting parts is to provide means for moving the blank holder 30 down below its normal position when it is desired to replace or remove the punch holder 26 and punches 21. This is done by exhausting air from beneath the piston 86 so as to drop the piston in the cylinders 8'! and then screwing the screws 85 outwardly until they again engage the lever B I. Then air is again admitted beneath the pistons 86. This will move the blank holder and connected parts to the position shown in Figure 6 bringing the cross bars 40 down below the punches 2'! so that the punches may be removed.

When it is desired to remove the die 25, air under pressure is admitted beneath the pistons 65, and the cylinders above the pistons are exhausted to the atmosphere through the valve 13. This will cause the parts to take the position shown in Figure 5 which will increase the normal space between the lower edge of the cross bars 40 and the upper face of the die 25 and thus greatly facilitate the removal of the die 25.

While I have shown my blank holder and the operating mechanism therefor as applied to a tie plate punch, it will be apparent to those skilled in the metal working art that it is equally well adapted for use with various other types of metal working machines, and it is to be understood that although I have shown only one embodiment of my invention, there are various changes that may be made in the details of construction and the combination and arrangement of the various parts within the scope of the claims, without departing from the spirit of this invention.

Having thus described my invention, what I claim is:

1. In a device of the character described, the combination of a supporting base, a reciprocating tool carrying slide thereabove, means for reciprocating said slide, a blank holder disposed between said base and said slide, means for operating said blank holder from said slide comprising, a lever pivoted intermediate its ends, operative connections between one end of said lever and said slide, a rod connected at its upper end to said lever and at its lower end to said blank holder, a second lever pivoted intermediate its ends, operative connections between one end of said lever and said blank holder, an expansible link connecting the other end of said second mentioned lever and the free end of said first mentioned lever, and yieldable, adjustable means connected to said rod for maintaining said parts in a definite predetermined position when the slide is in its uppermost position.

2. In a device of the character described, the combination of a frame, a supporting base secured to said frame, a tool carrying slide slideably mounted in said frame above said die support, means for reciprocating said slide, a blank holder operatively disposed between said support and said slide, means for operating said blank holder in timed relation to said slide from said slide comprising, a pair of levers pivoted intermediate their ends to said frame in vertically spaced relation to each other, operative connections between one of said levers and said slide, operative connections between said levers and said blank holder and an expansible link connecting the ends of said levers, yieldable means for maintaining the blank holder in a predetermined position when the slide is at the upper end of its movement.

3. In a device of the character described, the combination of a frame, a supporting base secured to said frame, a tool carrying slide reciprocally mounted in said frame above said base, means for reciprocating said slide, a blank holder disposed between said slide and said base, and means operated from said slide for moving said blank holder into engagement with the stock and holding it in engagement with said stock with a predetermined pressure comprising, a pair of levers pivoted to said frame, operative connections between said levers and said blank holder, operative connections between one of said levers and said slide, an expansible link connecting said levers, and means incorporated in said link for maintaining said link in its contracted position until a certain predetermined pull is exerted on said link by said levers, and means operatively connected to said blank holder mechanism for maintaining the blank holder in a definite predetermined position when the slide is in its uppermost position.

4. In a device of the character described, the combination of a frame, a supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder disposed between said base and said slide, a means for operating said blank holder comprising, a pair of levers pivoted to said frame, operative connections between one of said levers and said slide, operative connections between each of said levers and said blank holder, an expansible link connecting each of said levers, means for raising said blank holder above its normal at rest position when the slide is at rest in its uppermost position so as to increase the space between the base and the blank holder comprising, a cylinder connected to one of said levers, a piston slideably mounted within said cylinder and connected with the other of said levers, and means for forcing said piston upwardly in said cylinder, whereby said levers are rocked in opposite directions to raise the said blank holder above its normal position.

5. In a device of the character described, the combination of a frame, a supporting base secured to said frame, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said base and said slide and means for operating said blank holder in timed relation to said slide comprising, a cross-head, operative connection between said cross-head and said slide, an upper pair of levers pivotally connecting intermediate their ends to said frame, pivotal connections between one end of each of said levers and said cross-head, a pair of slideable rods slideably mounted in said frame, pivotal connections between each of said rods and one of said levers between the pivot point of said levers and their connection to said crosshead, connections between the other ends of said rods and said blank holder, a second pair of levers pivotally secured to said frame below said blank holder, a link connecting one end of each of said second mentioned pair of levers and said blank holder, a pair of expansible links, each of said links connecting one end of one lever of said first mentioned pair of levers to one end of one lever of said second mentioned pair of levers, and means for maintaining said blank holder in a predetermined position when the slide is at rest in its uppermost position.

6. In a device of the character described, the combination of a frame, a supporting base secured to said frame, a tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder disposed between said base and said slide, means for operating said blank holder in timed relation to said slide comprising, a lever pivoted to said frame above said slide, operative connections between one end of said lever and said slide, operative connections between said lever and said blank holder, a second lever pivotally mounted on said frame below said blank holder, operative connections between one end of said second mentioned lever and said blank holder, a cylinder pivotally connected to the free end of one of said levers, a piston slideably mounted in said cylinder and connected to the free end of the other of said levers and means for exerting a certain predetermined pressure against one face of said piston, and means for maintaining said blank holder in a predetermined position when the slide is at rest at the upper end of its movement.

7. In a device of the character described, the combination of a frame, a supporting base secured thereto, a tool carrying slide reciprocally mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said slide and said base and means for operating said blank holder comprising, a pair of levers, operative connections between said levers and said blank holder, operative connections between one of said levers and said slide, an eXpansible link connecting said levers and yieldable means for maintaining the blank holder in a predetermined position when the slide is at rest at the upper end of its stroke comprising, a lever pivotally mounted on said frame, operative connections between one end of said lever and said blank holder, a cylinder secured to said frame, a piston in said cylinder, operative connections between said piston and the other end of said lever and means for exerting a predetermined pressure against one face of said piston.

8. In a device of the character described, the combination of a frame, a supporting base secured thereto, a tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said base and said slide, and means for operating said blank holder from said slide for clamping the stock with a predetermined pressure, said means including a cylinder and piston, one of which is operatively connected toone side of said blank holder and the other of which is operatively connected to the other side of said blank holder, a means for exerting a predetermined pressure upon one face of said piston.

9. In a device of the character described, the combination of a frame, a supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said base and said slide, a cross-head, operative connections between said cross-head and said blank holder, a slip connection between said slide and said crosshead, whereby said slide moves a predetermined distance before moving said cross-head, means for maintaining the cross-head in a certain predetermined position until it is engaged by said slide.

10. In a device of the character described, the combination of a frame, a supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide comprising, a crank shaft rotatably supported by said frame, operative connections between said crankshaft and said slide, a bull gear rotatably supported on said crankshaft, a reduction gearing for rotating said bull gear, a clutch for clutching said bull gear to said crank shaft, means for automatically disengaging said clutch after the crankshaft has made one revolution, a blank holder operatively disposed between said base and said slide and operative connections between said slide and said blank holder for operating said blank holder with a dwell in its movement.

11. In a device of the character described, the combination of frame, a supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said base and said slide, a means operated by said slide for moving said blank holderin engagement with the stock and holding it therein with a certain predetermined pressure for a predetermined time comprising, a cross-head operatively connected to said slide, a lever pivotally mounted adjacent the upper end of said frame, a second lever pivotally mountedadjacent the lower end of said frame, operative connections between one end of the first mentioned lever and said cross-head, operative connections between the first mentioned lever and said blank holder, operative connections between one end of said second mentioned lever and said blank holder, a pair of cylinders, pivotal connections between said cylinders and the free end of said second mentioned lever, a piston slideably mounted in each of said cylinders, a piston rod secured to each of said cylinders, a pivotal connection between said piston rods and the free end of said first mentioned lever, means for exerting predetermined pressure against one face of said pistons and yieldable means for maintaining the blank holder in a predetermined position when the slide is at the upper end of its movement.

12. In a device of the character described, the combination of a frame, a die supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide comprising, a crankshaft rotatably supported by said frame, operative connections between said crankshaft and said slide, a bull gear rotatably supported on said crankshaft, a reduction gearing for rotating said bull gear, a clutch for clutching said bull gear to said crankshaft, means for automatically disengaging said clutch after the crankshaft has made one revolution, a blank holder operatively disposed between said base and said slide, operative connections between said slide and said blank holder for operating said blank holder with a dwell in its movement, and means for exerting pressure against the opposite face of said pistons when said slide is at rest in its uppermost position whereby said blank holder will be raised above its normal at rest position, so as to increase the space between the base and the blank holder to facilitate the changing dies carried by said base.

13. In a device of the character described, the combination of a frame, a die supporting base secured thereto, a reciprocal tool carrying slide slideably mounted in said frame above said base, means for reciprocating said slide, a blank holder operatively disposed between said base and said slide, operative connections between said slide and said blank holder for operating said blank holder in timed relation to said slide, yieldable means for maintaining said blank holder in a certain predetermined position when the slide is at rest at the upper end of its stroke and means for moving the blank holder in a direction away from said slide when said slide is at rest for increasing the space between said blank holder and the lower face of said slide so as to facilitate changing the tools carried by said slide.

WILLIAM F. LONGFIELD.

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