US3421397A - Rotary cam actuated reciprocating stamping press - Google Patents

Description

Jan. 14, 1969 H. s. CLARK 3,421,397

ROTARY CAM ACTUATED RECIPROCATING STAMPING PRESS Filed Dec. 6, 1965 Sheet 1 of 4 INVENT OR HARRY 5. CL ARK ammmmw ATTORNEYS H. s. CLARK 3,421,397

ROTARY CAM ACTUATED RECIPROCATING STAMPING PRESS Jan. 14, 1969 Sheet Filed Dec. 6. 1965 mm 2 On I,

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INVENTOR HARRY S. CLARK amzw zm 0M ATTORNEYS H. S. CLARK Jan. 14, 1969 ROTARY CAM ACTUATED RECIPROCATING STAMPING PRESS Filed Dec. 6. 1965 Sheet I INVENTOR HARRY 5. CLARK ATTORNEYS Jan. 14, 1969 H. s. CLARK 3,421,397

ROTARY CAM ACTUATED RECIPROCATING STAMPING PRESS Filed Dec. 6. 1965 Sheet 4 of 4 H n "W" "M1" "*1 "l il INVENTOR HARRY 5'. CLARK BY I dfltlizgfih d fimually ATTORNEYS United States Patent Oil-lee 3,421,397 Patented Jan. 14, 1969 9 Claims ABSTRACT OF THE DISCLOSURE A stamping press and the like including a plurality of vertically extending rotatable rods on which the dies are guided for sliding movement, drive means which rotates such rods in synchronism, and cam means interconnecting the dies and rods operative to reciprocate the dies as the rods are rotated, one form of the invention including opposed dies with both being guided and driven by the rods.

This invention relates generally as indicated to a press and more particularly to an improved press drive mechanism.

Since the advent of the steam engine the crank or eccentric has been almost universally employed to convert rotary to reciprocating motion and vice versa, and this principle has been adopted in many types of presses and is widely used to this day. However, such crank or eccentric driven presses have many disadvantages. For example, maximum tonnage can be applied only at the bottom of the stroke and a stroke of substantial length is required to obtain such maximum tonnage. Such conventional presses usually require large flywheels and the balance of a crank or eccentric type press is a compromise between static and dynamic balance of its crank or eccentric, such being inherently out of balance. Moreover, the side thrust created by the crank of a standard press creates wear on the sides of the moving parts requiring requiring costly guides which must often be replaced. There are many points in a crank type press Where tolerances must be closely held as for example in the crank itself, crank bearings, journal bearings, etc.

As an example, it is often times desirable to stop the punch after it has entered approximately 50% of the thickness of the material to be blanked and this ensures that the punch will then not enter the die. With the maximum tonnage being created at the bottom of the stroke and with tolerances difficult to hold, this cannot repeatedly be accomplished in a conventional crank type press and accordingly die wear is an important disadvantage. Thus in a conventional press it is often times impossible to prevent snap-through permitting the punch to move into the die causing wear of the tooling Because of the presence of flywheels and counter-balancing devices, it is apparent that a conventional eccentric or crank type press requires a power source having a capacity much larger than the actual work being done.

It is one principal object of the present invention to provide a press having a simplified drive and construction wherein with minor alterations, a wide variety of strokes may be employed.

A second principal object is the provision of a press wherein the maximum tonnage can be applied at any point in the stroke or several points, or for that matter over the total stroke; and, moreover, wherein the speed of the slide can be increased or decreased during each stroke.

Another object is the provision of a press wherein the amount of dwell or the portion of the stroke wherein the slide remains stationary can be varied to suit requirements of the dies or materials.

Still another object is the provision of a press and press drive which produces little or no vibration and does not require a large flywheel or counter balancing mechanisms as such.

A further object is the provision of a press wherein there is no side thrust on the vertically moving parts thus greatly reducing wear on the guides for such parts.

Another important object is the provision of a press wherein tolerances can closely be controlled and the travel of the slide can be stopped at any desired pointv with respect to the work or dies providing a more efficient press and increasing die life.

A yet further object is the provision of a press having a stroke no longer than that required by the Work it is doing.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the clams, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but one of a few of the various ways in which the principles of the invention may be employed.

In said annexed drawings:

FIG. 1 is a front elevation partially broken away and partly in section of one form of press in accordance with the present invention;

FIG. 2 is a fragmentary side elevation of the press shown in FIG. 1 partially broken away and in section;

FIG. 3 is a top plan view of the press of FIG. 1 taken substantially on the line 3-3 of FIG. l with certain parts removed for clarity of illustration;

FIG. 4 is an enlarged fragmentary section of a press similar to that shown in FIG. 1 but slightly modified to convert the same from a double-acting to a single-acting yp FIG. 5 is a front elevation partially broken away and in section of another embodiment of the present invention;

FIG. 6 is a side elevation of the press shown in FIG. 5 with another unit arranged in tandem therewith;

FIG. 7 is an enlarged fragmentary detail in section of the cam track and follower; and

FIG. 8 is a horizontal section taken substantially on the line 8-8 of FIG: 7.

Referring now to the annexed drawings and more particularly to the embodiment illustrated in FIGS. 1 through 3, it will be seen that the press comprises a lower bed plate 1 mounted on two legs 2 which serve both as legs for the press and as gear cases for power take-off drives used to drive feed mechanisms, scrap cutters, or the like. Rigid end columns 3 are mounted at both sides of the press bed and serve to carry a heavy duty fabricated top section 4 therebetween.

Four vertically elongated cam rods are located two at each end of the press, and each cam rod is provided with two vertically spaced cam tracks A and B therein cut one the mirror image of the other, one being located near the top of the cam rod, and the other near the bottom. These cam rods are mounted in the bed 1 by means of thrust bearings 6 and in the upper press frame 4 by means of radial bearings 7. Where the cam rods 5 project upwardly through the frame member 4, they are protected by oil sea-ls 8. The upper and lower members of the frame 4 and 1, respectively, are held together not only by the cam rods 5 journalled therein, but also by tie rods 9 at each corner of the press tightly secured to the bed 1 and upper frame 4 by the nuts illustrated.

At the lower end of each cam rod there may be provide-d a bevel gear drive 10 for the purpose of driving power take-off shafts 11 utilized to drive automatic feed mechanisms, scrap cutters, or the like.

The lower press bed 12 thus moves up and down on the cam rods with combination linear and radial sleeve bearings 13 mounted in the bed 12 surrounding the cam rods 5 which are protected by oil wipers and seals 14. Lower cam followers 15 are held in fixed relation to the lower bed 12 by cam follower pins 16 which are threaded into the bed as indicated and extend through and into the cam followers 15. It is thus apparent that this arrangement permits the bed 12 to move in a vertical direction, each stroke being one revolution of the cam rods 5.

The upper moving portion of the press as illustrated may comprise two parts relatively movable. The upper platen or bed 17 of the press is adjustably carried by a moving frame 18 and it is this adjustment which affords the necessary shut-height adjustment of the press.

Cam follower carrier and adjustment screws 19 are secured to the upper moving frame 18 through bearings 20 and 21 which are held tightly in adjustment by large locking nuts 22 threaded on the larger screw portion of the carrier 19. The cam follower carriers may be rotated by means of wormwheels 23 mounted on each as well as worms 24 connected together as shown at 25 so that a suitable handwheel or the like may operate all of the cam follower adjustment screws 19 simultaneously. Rotation is, of course, afforded between the lock nuts 22 and the frame 18 by means of the bearing 21, but as indicated the lower reduced diameter threaded portions of the carrier 19 are threadedly engaged with the upper platen 17 and accordingly rotation of the carrier 19 will vertically adjust the position of the bed 17 with regard to the frame 18 The cam follower adjustment screws 19 slide vertically on the cam rods 5 on linear and radial sleeve bearings 26 and 27 which are protected by oil seals as shown at 28. Cam follower 29 located in this section may be identical to the lower cam follower 15 and is held in place by cam follower pin 30 threaded into the carrier 19.

It can thus be seen that rotation of the cam rods through one complete revolution forces the upper and lower platens or beds 17 and 12 towards each other and then away again. The total distance moved is an amount equal to the total of the stroke of both cam tracks A and B in each of the four cam rods. It is here noted that the tooling is not shown but may readily be secured to the upper and lower platens by means of the conventional T-slots illustrated.

Referring now more particularly to FIG. 3 it will be seen that each of the cam rods 5 is tied together at the top of the press through gear train gears 31, 32 and 33. The four illustrated gears 31 are keyed to the upper projecting ends of the cam rods 5 and the two intermediate gears 32 are idler gears mounted on stub shafts 34. The single gear 33 is also an idler gear fastened to idler shaft 35 carried on the illustrated bearings and supported by frame assembly 36. The shaft 35 also carries a combination beltwheel, clutch and brake assembly 37 driven by the belts shown from relatively small electric motor 38. The beltwheel combination 37 may also serve as a flywheel and the clutch and brake assembly may be actuated to drive the cam rods through the aforementioned one complete revolution.

It is apparent that in operation, even though the speeds of operation may be very high, that there will be extremely little vibration. Vibration cannot occur from the cams because they are moving about a center axis which is completely balanced. Since the upper and lower platens are the only reciprocating parts of the press, moving through relatively short strokes and in directions opposite to each other, there will be a dampening action which will stop or substantially eliminate vibration at this point. Accordingly it can be seen that the press and press drive mechanism enables extremely high operating speeds to be obtained,

The double-acting cylindrical cam type press illustrated in FIGS. 1 through 3 has been found to be particularly useful in the higher speed presses utilized for blanking only where a short stroke is all that is necessary and considerable power and speed is required in heavy duty blanking operations. The double-acting cylindrical cam type press may also be used where an extra long stroke is required since each cam rod has a double cam with the upper one operating the upper bolster or slide of the press, and the lower one operating the lower bolster or bed. Such double cam arrangement affords a squeezing action where both sides of the die move simultaneously and a higher speed is achieved by the fact that each cam only moves the die or platen driven thereby one-half of the total stroke. For example, in a stroke required to be three-eighths of an inch for blanking purposes, each platen may travel but three-sixteenths of an inch.

Referring now to FIG. 4 there is illustrated a press which may be identical in form to the press illustrated in FIGS. 1 through 3 but which has cam rods 40 having only a single cam track C engaging the follower on the upper frame 18. The lower bed or bolster 41 of the press is mounted on the fixed bed plate 1 into which the cam rods 40 are journalled by means of the thrust bearings 6 illustrated. In this modification of the press the upper platen 17 is the only element which moves vertically through a stroke dictated by the configuration of the cam track C.

The four cam rods 40 may readily be replaced with the cam rods 5 or with cam rods having different cam track configurations simply by removing the bevel gearing 10 at the bottom of the cam rods and the nut 42. This permits the lower thrust bearing 6 illustrated to be disassembled and the cam rod to be vertically pulled from the press upon the removal of the covers 43 on the gear case 44. It is noted that there are two such covers 43, one for each pair of the cam rods and the drive gears 31 secured thereto. It will, of course, be appreciated that during the removal of the cam rods, the upper platen and frame will be blocked up and the pin 30 will be removed. It is thus apparent that the press can quickly be converted to and from a press having a double or single action as well as to a press having a different type of stroke simply by replacing cam rods with different configuration cam tracks. It is also here noted that the diameter of the rods at the cam tracks may be varied to increase the circumferential length of the track and accordingly provide closer stroke control.

Referring now to the embodiment of the press illustrated in FIGS. 5 through 8, there is shown a press employing but two cylindrical cams, one at each side, and such comprises a suitable rigid press bed 51 which is mounted on two legs 52 at each side thereof with an upper supporting member or plate 53 attached rigidly to the bed 51 by means of side or end plates 54. Cylindrical cam rods 55 are vertically mounted in suitable combination radial and thrust bearings as shown in the lower bed plate 51 and suitable radial bearings where they pass through the upper press member 53. In this manner the cylindrical eams 55 are rigidly supported vertically for rotational movement. These vertical cams 55 are hardened and ground and not only provide the vertical motion for the slide 56, but also provide total vertical guiding for such slide.

A cam follower pin 57 holds cam follower 58 fixed with relation to the slide 56. Each cam follower pin 57 is held in place by a cover plate 59.

Suitable bearings 60 are carried by the slide surrounding the cam rods 55 and these provide a bearing surface to carry the slide in its vertical motion. Seals 61 provided at the outer ends of the bearings 60 prevent the entry of dirt or foreign particles and accordingly prevent the loss of lubricant from around the cam track D.

The press slide 56 is equipped with a vertically movable tool carrying platen 62 mounted in locking gibs 62 and relative vertical motion between the platen 62 and slide 56 is provided by screw assemblies 64. There may be two such screw assemblies provided one on each side of the slide to provide a balanced holding of the movable adjustable parts. The turning of such screw assemblies 64 is accomplished through wormwheels 65 and worms 66 which are both mounted on shaft 67 to which a turning tool can readily be applied. This adjustment, of course, provides control of the shut-height of the press.

The cams 55 are tied together at the top of the press through gear train gears 68 and 69 with there being two gears 68 in mesh with the center gear 69. Each gear 68 is, of course, keyed to the top of the two cylindrical cams 55. Power to the gear train is supplied through shaft 70 journalled at 71 in frame 72 and connected to belt pulley and clutch and brake assembly 73. Power is supplied to the assembly 73 from electric motor 74 which in the FIG. 5 embodiment may be mounted at the back side of the press in a vertical position.

The combination radial and thrust bearings 75 rigidly mounting the earns 55 in the press bed 51 rigidly support such cams and the upper end of each ca-m rod is supported by radial bearing 76 protected by oil seal 77. Such oil seal prevents the oil in the gear case 78 having removable cover 79 from seeping out of the gear case down through the bearing.

In FIGS; 7 and 8 there is illustrated in detail the cam follower and pin holding the same in the vertically movable frame or press head 56. The follower 58 may be of the yoke or semicircular type which closely fits within the cam track D and snugly surrounds the reduced diameter portion 80 of the cam rod 55. Both the top and bottom surface of cam follower 58 are provided With the beveled edges indicated at 81 in FIG. 7 so that the follower will smoothly follow the path dictated by the track D. The plate 59 is, of course, removably held in place by the fasteners 82 and an O-ring 83 provides a seal cooperating with the seals 61 at the top and bottom of the cam rod aperture through the slide 56. Both the follower 58 and the pin 57 will, of course, be made of hardened wear resistant material and it can be seen that the pin can be removed laterally as seen in FIG. 7 and the follower can then be pulled from the machine with the cam rod 55. The cam rods can be removed simply by removing the nuts 85 at the bottoms of the cam rods 55 and with the follower pins 57 removed as well as the cover 79 of the gear case 78, the cam rods may then simply be pulled axially from the machine.

Referring now to FIG. 6 there is illustrated two press units of the type shown in FIG. 5 positioned side-byside and driven from a common motor 90. The press units designated as 91 and 92 are simply interconnected by the belt drive 93 at the top thereof to rotate the belt pulley, clutch and brake assemblies 94 and 95 which drive the center gear 69 of each press in mesh with the gears keyed to the cam rods 55. Such assemblies 94 and 95 which are similar to the assembly 73 shown in FIG. 5 also may serve as flywheels for the operation of the press. The single electric motor is connected to the assembly 94 by the belt drive 96 and it will be appreciated that additional units may also be stacked together in the manner indicated to provide a transfer press wherein an automatic feeding mechanism would feed a part through the press and each one would perform its own stamping or punch ing operation on the part to be formed. It will be appreciated that the power source 90 may be increased in size and capacity depending upon the number of units driven thereby. The press units 91 and 92 are in all other respects identical in form to the press units shown in FIG. 5.

Referring again to FIG. 5 it can be seen that when the clutch assembly 73 is engaged it applies the power furnished by the motor 74 to the gear 69 and thus to the gears 68 keyed directly to the cam rods 55. As the cam shafts rotate, the cylindrical cam track forces the cam follower 58 which is fixed through cam follower pin 57 to the slide 56 to move in a vertical direction. The vertical movement or stroke of the press will, of course, be determined by the amount of throw on the cam track. The speed of the slide at all times during the stroke is controlled by the pitch of the cam. The slide 56 of the press travels vertically on the bearings 60 which surround the cam rods 55 and such vertical motion travelling up and down the stroke length is determined by the design of the cam track itself. Since all motion is developed through the axis of each cam rod, no lateral or side vibration is caused by the movement of the slide and all force applied is directly in a vertical or radial orientation. By cam design the amount of force applied to the vertical motion of the slide 56 can be varied, and, of course, so can the speed at any point of the stroke. The total tonnage of the press can be applied at the start of the stroke or at any part of the stroke. It will also be appreciated that the press drive illustrated can be applied to a press having the slide running in any direction. For example, horizontally extending cam rods and a horizontally movable slide may be a distinct advantage in permitting top-to-bottom feed of coil stock.

It has been found that the illustrated press works ideally as a drawing press in which at the initial instant where the punch strikes the material, total tonnage can be applied and as the material starts to move, the tonnage may be slacked off and the speed of the slide increased. As the slide reaches the bottom where a coining efiect is needed, the tonnage can then be increased greatly. All of this increase and decrease in tonnage throughout the stroke is, of course, simply governed by a properly designed cam track. The pitch of the cam, of course, determines the tonnage and velocity at any particular point in the stroke and the greater the pitch, the higher the velocity and the less the tonnage.

It can now be seen that there is provided an improved and highly simplified press and press drive mechanism which provides many advantages over conventional crank or eccentric type presses.

Other modes of applying the principles of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

1, therefore, particularly point out and distinctly claim as my invention:

1. A press comprising a frame, a guide rod rotatably journalled in said frame, a slide mounted about said guide rod for sliding movement therealong, cam means interconnecting said guide rod and slide operative to convert rotary motion of said rod into reciprocating motion of said slide, and means operative to rotate said guide rod.

2. A press as set forth in claim 1 including a second slide mounted on said guide rod for sliding movement therealong, and cam means interconnecting said guide rod and said second slide operative to convert rotary motion of said rod into reciprocating motion of said second slide, the motion of said second slide being opposite that of said first mentioned slide to provide a double-acting press.

3. A press as set forth in claim 1 including at least two guide rods journalled in said frame, and common drive means operative to rotate said guide rods at the same rotational speed.

4. A press comprising a frame, a cam rod journalled in said frame, a slide mounted on said cam rod for sliding movement therealong, cam means interconnecting said cam rod and slide operative to convert rotary motion of said rod into reciprocating motion of said slide, means operative to rotate said cam rod, said slide comprising cylindrical screw means surrounding said cam rod and journalled in a first frame, a second frame threadedly connected to said cylindrical screw means, and means operative to rotate said cylindrical screw means to adjust the position of said second frame with respect to said first frame.

5. A press comprising a frame, a bed portion and a top portion supported on said bed portion spaced therefrom, a plurality of parallel cam rods extending between said bed portion and top portion journalled therein, a slide, said cam rods extending through said slide and being confined for movement therealong, cam slots in said rods, a follower in each cam slot, means locking said followers to said slide, drive means for said rods operative axially to rotate the same and thus to move said slide along said rods, a second slide mounted on said rods for movement therealong, and corresponding cam slots and followers in said second slide operative to move said second slide along said rods toward and away from said first mentioned slide in timed relation therewith.

6. A press set set forth in claim 5 including four cam rods arranged symmetrically two on each side of said press.

7. A press as set forth in claim 6 wherein said drive means includes a gear train interconnecting said cam rods and a clutch and brake unit, and a drive motor operative to drive said clutch and brake unit.

References Cited UNITED STATES PATENTS 1,076,163 10/1913 Shirley 100292 1,060,662 5/1913 Bauroth 100-292 2,172,701 9/1939 Eustege 100292 2,891,408 6/1959 Burt 7457 WILLIAM S. LAWSON, Primary Examiner.

U.S. c1. X.R.

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