US2286943A - Punch press - Google Patents

Description

June 4 D. c. VERSON Em 2,286 9 3 PUNCH PRESS Filed Oct. 14, 1940 3 Sheets-Sheet 1 June 16, 1942. o. c. VERSON ET AL PUNCH PRESS Filed Oct. 14, 1940 3 Sheets-Sheet 2 n l n m U u Patented June 16, 1942 UNITED STATES PTQNT OFFICE PUNCH PRESS ware Application October 14, 1949, Serial No. 361,040 9 Claims. (Cl. 192 -144) This invention relates to punch presses, and more particularly to a mechanical punch press having a stroke of variable length.

The term punch press is used in its generic sense in this application and is meant to include press brakes, extruding presses and similar metal deforming machines.

In the past, the principal disadvantage of mechanical presses, as compared with hydraulic presses, was that although a mechanical press could be constructed to have a long stroke and might, therefore, be admirably suited for some particular manufacturing processes, yet such a press was not readily adaptable for use in drawing operations wherein a shorter stroke was adequate. The principal disadvantage inherent in a press having an invariable stroke is that such a press having a long stroke of, say, thirty inches, for instance, must necessarily have a comparatively slow cycle of operation, since the crank or eccentric must be started from its uppermost position, moved downwardly through its lowermost position and back upwardly to its uppermost position again. If the effective stroke desired from such a press is short, for instance only four inches, it will still be necessaryto move the slide from its uppermost position downwardly to within four inches of the bottom of its stroke before doing any work on the metal to be deformed. Likewise, the entire upward stroke from the lowermost position of the crank to its uppermost position is similarly wasted since no work is done.

Therefore, the principal object of our invention is to provide a punch press wherein the length of stroke may be predetermined and preset from a minimum of nothing to a maximum of the full stroke for which the machine is intended.

An additional object is the provision of such a press wherein the length of stroke may be preset without the necessity for complicated adjustments to the crank mechanism itself.

Still a further object of our invention is the provision of a mechanical punch press wherein the adjustment of the stroke is such a simple operation that it is feasible to use successive strokes of different lengths in a manufacturing process, if desired.

An additional object of our invention is the provision of a punch press having a stroke of variable length wherein the time of the cycle of operation of the press is progressively shorter as the stroke is shortened.

Other objects and advantages will become apparent from the following description of a preferred embodiment of our invention, taken in conjunction with the accompanying drawings in which similar characters of reference refer to similar parts throughout the several views:

Fig. l is a somewhat diagrammatic front view of a press embodying the present invention;

Fig. 2 is a left side view of the press illustrated in Fig. l, and v Fig. 3 is a somewhat diagrammatic sectional view, taken in the direction indicated by the arrows along the line 3-3 of Fig. 1, showing the construction and arrangement of parts in the press crown. The control mechanism is also diagrammatically shown in this view.

In punch presses as ordinarily constructed, a heavy flywheel is rotated at a substantially constant speed by a prime mover. When the operator presses the proper control, an electrical, mechanical or pneumatic means, or a combination of these control means, engages a clutch which connects the crank shaft to the fly wheel, while simultaneously a brake which prevents the crank shaft from moving is released. Thus, the fly wheel is connected to the crank and the energy stored in the fly wheel rotates the crank from its uppermost position downwardly through its lowermost position and upwardly toward its uppermost position once again. As the crank reaches this uppermost position, automatic mechanism comes into play to disengage the clutch between the fly wheel and the crank, while simultaneously the brake is applied. Thus, the crank shaft is stopped at this uppermost position in preparation for a second cycle.

It will be seen that this construction necessitates that the crank shaft always rotate through a complete revolution in order to complete a cycle of operation and that, therefore, the slide connected by a pitman to the crank shaft always passes through a full stroke.

In the press of our invention we also use a fly wheel which is driven at a constant speed by a prime mover. We connect this fly wheel alternately by means of a pair of clutches to two separate gear trains connected between the clutches and the crank. One of these gear trains contains an idler gear not found in the other gear train in order to reverse the direction of rotation of the crank shaft relative to the fly wheel. Thus, by

engaging one clutch, we are able to swing the crank pin in one direction, while by engaging the other clutch, the crank shaft may be rotated in the opposite direction. 7

In connection with this arrangement we also provide a control mechanism which disengages which ever clutch has been previously engaged and simultaneously applies the brake before the crank pin is returned to its uppermost position. Thus, for instance, starting with the crank pin positioned at a point in its cycle a matter of or so from its lowermost position,- a control is prearranged by the operator to determine the length of stroke desired.- The punch press operating control is then actuated, thereby causing the control mechanism to release the brake and engage the appropriate clutch. The fly wheel-V then swings the crank through its lowermost position and upwardly once more to the point predetermined by the operaton At this point in its cycle the automatic controlmechanism will cause the clu'tch'to become-dis-- engaged and the brake to be applied, thus stopping the press. When the operator next operates. the press starting control, the mechanism will cause the other of the two clutches to-be en gaged simultaneously with the release of the be seen that only half as many revolutions of the fly wheel will be required to rotate the'crank a half revolution as would be required to'rotate the crank a full revolution.

In the embodiment of our inventioniillustrated in the drawings we have shown apunch press having-a stroke variable from zero to a maximum of approximately thirty inches. This press, indicatedgenerally by the numeral I0, is comprised of a frame I2 and a slide l4. At the lower portion of the frame, a bed It supports a lower die element It, while the lower surface of the slide it carries the cooperating die element 20. At the upper portion of the frame, the press is provided With a crown 22 which carries a cross shaft. 23. At its center this shaft journals an eccentric 25 which-is connected by means of an eccentric strap 28 to the press slide 14. Thus, rotation of the eccentric 26 causes the. eccentric strap 23 to reciprocate the slide M toward and away from the bed I8. The eccentric 28 is secured at each side to a large gear 38, these gears being meshed with smaller pinions 32 carried upon a cross. shaft 34' journal'ed' at its ends at in the press crown.

Referring particularly to Fig.3, it will be seen that the left-hand end of the shaft 34 is keyed to a large gear 33 meshed with a pinion 40. The pinion is in turned mounted upona short shaft tip-ositioned parallel to the shaft 34' and journaled at its ends inthe press crown. A large gear 5 1 carried upon this shaft 42 is meshed with apinion 46 mounted upon a primary drive shaft 48.

Similarly, the rig-ht hand end of the shaft 34 is provided with a gear 58 meshed with a pinion carried by a short shaft 54. This short shaft 54 also carries a large gear 55 meshed with an idling or reversing gear 58 which, in turn, is meshed with a pinion 60 keyed to a second primary drive shaft 62.

The ratios of the two gear trains between the ends of the primary drive shafts 48 and 62 and the shaft 34 are the same, excepting that the idling or reversing gear 58 found in the righthand train is not present at the left-hand side of the press, thus causing the two primary drive shafts ta-and 62 to rotate at the samespeed, but in opposite directions.

The two primary drive shafts 48 and 62 are in axial alignment with their outer ends journaled in suitable bearing members in the press crown. The: inner ends of these shafts are closely adjacent eachother and are journaled to rotate relative to-awheel 64. This fly wheel 64 is -'carried in bearing-members 68 in the press crown,

tween the bell and disc.

Within-the bell"'l'2,' a collar- 18 keyed to the shaft 62, is provided with an'outwardly radiating annular clutch driven plate 18 5which is positioned closely adjacent the face of the driving disc 14. A similar annular clutchdriven plate is positioned on the opposite or outward side of the driving disc 14-and is free to move longitudinally relative to the clutch plate '-l8onsplines 19-, but is prevented'from rotating relative to this plate.

A piston 82 operating in a' cylinder 84 secured to the shaft 62, acts to urge the driven plate 85- toward the driven plate 18 when the cylinder 34 is placed under pneumatic pressure. This cylinder receives-air under pressure through a port 8B whichcommunicates witha longitudinallyextending passage 88in the shaft 62. Air is fed to orexhausted' from thispassage 83 through anair line SD and cap92. Thecap 92 fits-overthe'outer end of" the shaft 52 and is sealed to'the shaftby a cup washer 93 or other suitable rotary sealE Thus; byadmitting air under pressuretothe airline-', air is caused to flow through the'cap- 9'2 passage 88; and thence through the port 86into the cylinder 84. The resulting increase inpressure in the cylinder 84 moves the piston 82 toward the fly wheel; thus pushing the clutch plate 88 against the-disc T4. Continued movement of this piston urges the clutch disc M -against the inner clutch plate 18 sothat the clutch disc 14- istightly clamped between the two driven-plates wand 88, thus causing the shaft 62 -t'o revolve with the fly wheel 64.

A- plurality of coil springs 94 bear with one of their ends-against the outer face of the cylinder 84 and with their other ends against heads 96 of clutch release pins 98- which extend through openings in the cylinder 84 and are connected at their inner ends to the piston 82. These springs urge the piston toward the right, thus disengaging the clutchwhen air is permitted to flow fromthe cylinder 84.-

A similar clutch I08 is arranged at the lefthand side of the fly wheel 84 and similarly connects the flywheel to theshaft 48 when engaged. This clutch is actuated by a piston- H32 acting in a pneumatic cylinder [Min the same manner as piston 82 actuates the previously mentioned clutch H,

Directly to the left of the clutch cylinder I24 the shaft 48 is provided witha collar- I06, the

external face of which is splined at I08. A bell IIII, secured to the crown at the left-hand side of the machine, extendsinwardly and surrounds the shaft and at approximately the mid point of the collar I06 is provided with an annular brake disk H2. The connection between the brake disc H2 and the bell II is splined at II4 to permit a limited longitudinal movement of the brake disc, but prevents relative rotation between these elements.

An annular brake plate I I6 is slidable on the splines at I08 and is secured to the outer ends of clutch release pins H8. These pins extend through the cylinder I04 and are secured at their opposite ends to the piston I02, while the portions of the pins between the cylinder I04 and the brake plate II6 pass through coil springs i530. Thus, these springs I20 act in the same manner as the spring 94 to release the clutch when air is exhausted from the space within the cylinder I04. In addition, it will be seen that since their outer ends are connected to the brake plate II 6, the springs will urge this brake plate against the brake disc II2 simultaneously with the disengagement of the clutch I00.

At the opposite side of the brake disc II2 the splined collar I06 is provided with a similar slidable brake plate I22 which is connected by brake release pins I 24 to a brake release piston I26 slidable in a cylinder I28. The cylinder I28 is secured to the shaft 48 in the same manner as the cylinder I04. Thus, movement of the piston I26 toward the left pulls the brake release pins I24 toward the left, thus pulling the brake plate I22 away from the disc I I2. Coil springs I30 surround the pins I24 and bear with their opposite ends against the plate I22 and the release cylinder I28, so that the brake plate I22 is normally pushed toward the right by these springs. The two cylinders I04 and I28 are connected by concentric passages I32 and I34 in the shaft 48 to air lines I36 and 90, respectively, through the medium of a cap I38 having a pair of rotary seals I40 and I42 so that air may be admitted to or exhausted from either the cylinder I04 or the cylinders 84 and I 28 together.

When at rest, all of the cylinders will be at substantially atmospheric pressure. Thus, both of the clutches will be disengaged while the springs I20 and I30 act to urge the brake plates H6 and I22 from opposite directions against the brake disc II2, thereby preventing rotation of the shaft. Simultaneously with the engagement of the clutch I00, the brake plate H6 will be drawn toward the right and the brake released. If, on the other hand, cylinder 84 is placed under pressure to engage clutch II, the arrangement of the air lines is such that brake release cylinder 28 is simultaneously placed under pressure to move the brake plate I22 to the left and release brake disc II2, thereby permitting free rotation of the driving mechanism. It will be seen, therefore, that by alternately engaging and disengaging clutches I00 and H, the eccentric 26 is alternately driven through the gear trains at alternate sides of the press, while all of the braking is done through the gear train at the left-hand side of the press, as Viewed in Fig. 3.

The control mechanism shown diagrammatically in the drawings is merely an example of one type of control by means of which the press may be operated in the manner we have described.

Referring to the lower portion of Fig. 3, we

have shown a manually and automatically operable rotary valve I44 which, when revolved in a counter-clockwise direction, assumes the position shown. In this position air passes from an air receiver, not shown, through the conduit I46 and by way of a passage I48 in the air valve to a conduit I50, thus putting the conduit I 50 under pneumatic pressure. When the valve I44 is rotated in a clockwise direction, air passes from the con duit I50 by way of a branch passage I52 in the air valve, through the air valve passage I48 and thence to an exhaust line I54. Thus, with the valve I44 rotated to its clockwise position, the air in conduit I50 is exhausted to the atmosphere, thus placing this conduit at substantially atmospheric pressure.

The conduit I 50 leads to a rotary selector valve I56 which serves to distribute the air to either one or the other of the press clutches. Thus, with the valve I56 rotated to its counterclockwise position as shown, air under pressure passes from the conduit I50 through a passage I58 in the valve I56 and through air line I36 leading to cylinder I04. Simultaneously the air line is connected by means of a passage I60 in the air valve to an exhaust line I62, thus placing cylinders I28 and 84 at substantially atmospheric pressure. With the valve rotated to its counterclockwise position, air line 90 will be connected to the conduit I50 through the medium of a passage I64 in the valve I56, while air line I36 will be connected to the exhaust line I62 by means of a valve passage I66.

With this arrangement the operator will, for instance, swing an appropriate lever which moves valve I56 to the position shown. Then valve I44, which previously had been in its clockwise position, is swung in a counter-clockwise direction to the position shown. Air then passes from the air receiver, not shown, through the air line I46, passage I48, conduit I50, passage I 58, and air line I36 to the cylinder I04. This moves piston I02 to the right and engages clutch I00 while simul taneously releasing the brake. The fly wheel then swings the eccentric through the medium of the gearing at the left-hand side of the press through the portion of the cycle desired, whereupon air valve I44 is swung to its clockwise position, thus permitting the air in cylinder I04 to escape through air line I36, passage I58, conduit 1'50, air valve passages I52 and I48 to the exhaust line I52. This permits the springs I20 to disengage the clutch and apply the brake, thus stopping the press.

Before the next stroke of the press, the selector control lever is moved to rotate valve I56 to its clockwise position so that when valve I44 is again rotated to its counter-clockwise position as shown, air will pass from the air line I 46 through passage I58, conduit I50, valve passage I64 and air line 30 to cylinders 84 and I28, thus engaging clutch II and moving brake plate I 22 to the left to release the brake. The eccentric is then driven through the gearing at the righthand side of the press, thus swinging the eccentric in the opposite direction through its lowermost point and upwardly to the proper position, whereupon air valve I44 is again swung in a clockwise direction to permit air to be exhausted from the cylinders 84 and I28 to stop the press. During the above cycle cylinder I04 is connected to the atmosphere through air line I36. valve passage I66 and exhaust line I62.

Referring to Fig. 1, an automatic and simple arrangement is shown for stopping the press at the desired point in its cycle. This arrangement consists of a vertical bar no which extends along the press column and is adapted to reciprocate in guides Ill. The lower end of this bar is pivotally connected to the valve I44 at IHl so that movement of this bar in an upward direction swings the valve Hi l in a counterclockwise direction, while downward movement of this rod swings the valve IM in a clockwise direction,

This rod I78 is automatically moved downwardly to shift the valve I44 to its clockwise position by means of a generally horizontal lever I15 pivoted to the bar I'II'I and to a pin I18, fixed in the press frame and spaced somewhat inwardly from the bar I'll), The end of the lever I76 opposite to that pivoted'to the bar I'IEI is provided with a leaf spring I82 which extends transversely in front of thepress slide M. Behind the leaf spring I82 the press slide is provided, with a vertically extending rail let to which av movable stop member I85 may be clamped at any point. As the slide moves upwardly, the stop member I875 carried therewith impinges against, the leaf spring I82 and moves the leaf spring upwardly, thus shifting the rod Iii! downwardly and rotating the valve M4 to its clockwise position and, by the arrangement previously described, stops the press. With. the

press slide in this position against the spring nember I82, the. valve ismaintained, resiliently in. this position.

To start the next cycle of operation after shifting the selector valve I56, the operator shifts the valve I44 to its counter-clockwise position 3 against the pressure of thespring I32 and holds it there momentarily until the slidehas moved downwardly sufficientl to carry the stop member I85 away from the spring I 22. The operator then removes his hand from the control lever of valve IM so that when. the slide moves upwardly again, the. stopping member I86 will be able once more to shift the. rod Ilil downwardly to stop the press. The member I35 may be clamped. at any pointalong the rail I35 so i that the press slide may be permitted tomove upwardly to the desired point before it automatically disengages the clutch and applies the .brake. l

Having thus described our. invention, what we desire to secureby. United States Letters Patent is;

1. In a, variable strolge mechanicalpunch press of the type having a press frame, a slidereciprocable in the frame, rotatable means to reciprocate said slide, a. fly wheel, and means to To.- tate said fly wheel, in one direction: meansincluding a clutch operable selectively to drive said rotatable means in one direction from said fly wheel, means including another clutch selectively operable to drive said rotatable means fromsaid fly wheel in another direction, a brake to prevent rotation of said rotatable means, and means to release said brake substantially simultaneously with the engagement of either of said clutches and to apply said brake whenever both of said clutches are disengaged.

2. In a device of the class described havingv a press frame, a slide reciprocable in said frame, rotatable eccentric means to reciprocate said slide, and a fly wheel: a pair of gear trains selectively operable to rotate said rotatableeccentric means from said fly wheel, means selectively to drive. said rotatable eccentric means through alternate of said gear trains, means automatically to stop the rotation of said rotatable means at any selected position of said slide during upward movement' of said slide, said means including a brake, and automatic means to disestablish driving relationship between said fly wheel and said rotatable eccentric means and substantially simultaneously to apply said brake.

3. In a punch press of the type having a frame, a slide reciprocable in said frame, rotatable eccentric means to reciprocate said slide, and a rotatable fly wheel: selectively engageable clutch means operable selectively to drive said rotatable eccentric means from said fly wheel in either direction, brake means toprevent rotation of said rotatable eccentric means, pneumatic means selectively to operate said clutch means and to operate said brake means, and means to control the flow of air to and from said pneumatic means, whereby said rotatable eccentric means may be revolved through less than a complete revolutionand whereby said rotatable eccentric means may be rotated alternately in opposite directions.

4. In a mechanical punch press having a frame, a slide reciprocable in the frame, eccentric means connected to said slide and adapted when rotated through one complete cycle of revolution to cause said slide to move from its uppermost position to its lowermost position and to return to its uppermost position, a flywheel and means to rotate said flywheel at a substantially uniform velocity: clutch means adapted selectively to connect said flywheel to said eccentric means to cause said flywheel to rotate said eccentric means in one direction or alternatively to cause said eccentric means to be rotated in the opposite direction, brake means adapted when applied to stop rotation of said eccentric means, means to apply said brake means when said clutch means is disengaged and to, release said brake means when said clutch means is engaged, and pre-set automatic means operative after the start of a cycle brought about by engagement of said clutch means and release of said brake means to disengage said clutch means and to apply said brake means after said eccentric means has moved through a portion of a cycle including movement through its lowermost position but before said eccentric means has. moved through a complete cycle.

5. In a mechanical punch presshaving a frame, a slide reciprocable in the frame, eccentric means connected to said slide and adapted when rotated through one complete cycle of revolution to cause said slide to. move from its uppermost position to its lowermost position and. to return to its uppermost position, the distance between said uppermost and lowermost positions constituting the maximum length of stroke of said press, a flywheel and means to rotate said fly- Wheel at a substantially uniform velocity: connecting means between said flywheel and said eccentric means by means of which said eccentric means can be, rotated in either direction from said flywheel, adjustable control means to stop the rotation of said eccentric means during the upstroke of said slide when said slide is at any predetermined intermediate position between its uppermost and lowermost positions, and control means adapted to. be operated thereafter for causing said slide to move from said intermediate position, through its lowermost position and to an intermediate position substantially the same distance from its lowermost position as. the prior intermediate position, said adjustable means being adapted to stop the upward movement of said slide when it has reached the last said intermediate position.

6. In a mechanical punch press having a frame, a slide reciprocable in the frame, eccentric means connected to said slide and adapted when rotated through one complete cycle of revolution to cause said slide to move from its uppermost position to its lowermost position and to return to its uppermost position, a flywheel and means to rotate said flywheel at a substantially uniform. velocity: clutch means adapted to connect said flywheel to said eccentric means to cause rotation of said eccentric means in one direction, other clutch means adapted to connect said flywheel to said eccentric means to cause said flywheel to rotate said eccentric means in the opposite direction, brake means adapted to restrain said eccentric means against rotation, means normally engaging said brake means when both of said clutch means are disengaged and disengaging said brake means when either of said clutch means is engaged, control means operative to engage one of said clutch means and to disengage said brake means to cause movement of said slide from an intermediate position through its lowermost position to substantially the same intermediate position at which said slide was started, the above movement being accompanied by rotational movement of said eccentric means in one direction and control means operative to condition said clutch means so that subsequent operation of the first control means will cause said flywheel to rotate said eccentric means in the opposite direction to cause said slide to move from its said intermediate position through its lowermost position and to return to its said intermediate position.

7. In a mechanical punch press having a frame, a slide reciprocable in the frame, rotatable means connected to said slide and adapted when rotated to cause movement of said slide through a cycle of operation, a flywheel and means to rotate said flywheel at a substantially uniform velocity: means to rotate said rotatable means from said flywheel in either direction and to restrain said rotatable means against rotation, said means comprising a clutch to connect said flywheel to said rotatable means by way of a forward driving gear train, a second clutch to connect said flywheel to said rotatable means by way of reversing gear train, brake means to restrain said rotatable means against rotation, pneumatic means adapted when in one position to cause engagement of said brake means and disengagement of both of said clutch means and when in another position to cause disengagement of said brake means and engagement of a selected one of said clutch means, and means to select which of said clutch means is to be engaged by the last said means when in the second of its alternative positions.

8. In an eccentric type punch press having a frame, a slide reciprocable in the frame, eccentric means connected to said slide and adapted when rotated through one complete cycle of revolution to cause said slide to move from its uppermost position to its lowermost position and to return to its uppermost position, a flywheel and means to rotate said flywheel at a substantially uniform velocity: actuating and control means to cause said slide to move through a stroke shorter than its maximum stroke, the last said means comprising means to connect said eccentric means to said flywheel so as to cause rotation of said eccentric means in one direction, means to connect said eccentric means to said flywheel to cause rotation of said eccentric means in the opposite direction, means to restrain said eccentric means against rotation, and automatic control means to limit the upward movement of said slide to a p-re-set position between its upper and lower limits, said control means adapted to disengage said connecting means and to apply said restraining means.

9. In a mechanical punch press having a frame, a slide reciprocable in the frame, eccentric means connected to said slide and adapted when rotated through one complete cycle of revolution to cause saidslide to move from its uppermost position to its lowermost position and to return to its uppermost position, a flywheel and means to rotate said flywheel at a substantially uniform velocity: alternating operating brake and clutch means adapted alternately to restrain said eccentric means against rotation and to rotate said eccentric means from said flywheel, said clutch means being adapted to rotate said eccentric means in either direction, control means adapted to cause engagement of said clutch means and disengagement of said brake means to cause movement of said slide, and automatically operable means adapted to disengage said clutch means and to apply said brake means at any predetermined point of movement of said eccentric means after said slide has moved through its lowermost position, and means operative thereafter to cause said flywheel to again be connected to said eccentric means to cause rotation of eccentric means in the opposite direction, where- I

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