GB2230219A - Deep-drawing punch press - Google Patents

Abstract

A punch press for deep-drawing operation has two vertically spaced crankshaft cam mechanisms 4, 5, Fig.1, an upper slide 6 driven by the upper crankshaft cam mechanism 4 to move up and down, and a lower slide assembly 7 including spaced apart slides 74a-74d capable of vertical reciprocation at different time intervals when driven by the lower crankshaft cam mechanism 5 through a set of push rods 76a-76d. A bed 8 is fixed by its lower part above the upper part of the lower slide assembly 7 to be directly opposed to the movable upper slide 6 which carries an upper die 9A in alignment with a lower die 9B carried by the fixed bed 8. The punch press, in a single action stroke, is capable of accomplishing a series of processes such as blanking, multi-stage deep drawing trimming, shaping and stripping on a workpiece W held between the dies 9A, 9B. Each process involves the use of stamping dies 97a-97d Fig.5(B), connected by push rods 99a-99d to respective ones of the slides 74a-74d. Trimming is effected by co-operation of die 97c and cutting die 95. A punch pin 98 effects final forming of the workpiece W. <IMAGE>

Description

DEEP-DRAWING PUNCH PRESS The present invention relates generally to a punch press and, more particularly, to a deep drawing punch press, which, by means of an upper and a lower units of the coupling crank shaft cam mechanisms with cooperation of the relative up-anddown movement of an upper slide driven by the respective mechanisms and a set of lower slides disposed beneath the fixed bed plate and capable of sliding according to the order of tiers, is capable of subjecting metal sheet material laid on a concentric die set to a series of processes of blanking, multi-punch forming (one-time press forming, two-time press forming, three-time press forming, ...), trimming,shaping and stripping on one rotatory movement, that is, on one power stroke, of the crankshaft cam mechanisms, and forms the material into a cavity, container-shaped formed product.

Currently, because of limits on the thickness of material, the ductility and the rate of drawing, the forming of deepdrawn products of cavity containers, such as, cylinder casings of air filters, oil cans, cans and pots, generally needs to be divided into a number of punch processes, namely, processes of blanking, multi-punch forming from shallow to deep, trimming, shaping and stripping for accomplishment. In order to perform the press forming operation, there usually utilizes in the single-machine single-acting manner the conventional punching machines or presses cooperating with a plurality of different die sets to subject the blank to actions of blanking, multipunch forming and trimming singly, changing the different die sets by batch and by rotation in accordance with the number of processes required.This not only takes longer working hours, the work efficiency is also very low and because of the multi-punch processes and the production and installation of different die sets, the accumulative error produced is also very large. In addition, the hardening in the work piece, caused by the work waiting time and the change in temperature difference of the work piece as it is transferred each time from one press process ahead to the one press process following, leads to a fall in the quality of product and hence the efficiency of production becomes very low making it thus unsuitable for large-scale production.In order to arrive at a consistent integration operation to be suitable for large-scale production and to raise work efficiency, there generally uses the same number of punching machines as the press processes arranged in a row with each of the punching machines having a set of dies installed thereon. In operation, the blank is first processed in the first punching machine for pressing and shearing and next transferred to the second punching machine for processing, and then to the third punching machine and so on till finally a finished product is accomplished. This follows what is generally known as the"multimachine division of labor" system and by which, because each of the press processes has joined to form an integrated work it is thus possible to reduce the time for change of dies, for work waiting and for material waiting.Since the entire press operation can almost be finished within the same time, there is also the advantage of enhancing the work efficiency. However, drawbacks are still present, such as, the large cumulative processing error as induced by the error in the making and installing of each die set and the difference in the precision of each of the punching macnines, and the work hardening and the fall in quality induced as the workpiece when transferred each time from one punching machine ahead to the one punching machine following is subjected to interval multipunch friction to produce heat and to the cooling by air after the stripping.

In addition, there also brings in some new problems, such as, to add more apparatus and equipment, to increase the acreage occupied by the factory building and to increase the power used.

In order to reduce the number of pressing processes in a deep-drawn product and to reduce the number of punching machines used and the area occupied by the machines, there is found a method whereby combination dies are used in cooperation with the conventional multiple-action crankshaft press or moving bed press to complete continuously a number of processes of stamping in a single stroke. Nevertheless, because of the limits in construction and action of the conventional press usually it accomplishes mostly the shearing, a single-press forming and double-press forming only, or is possible to subject the pre-sheared blank to three processes of one-time to three-time press forming without being able to accomplish multi-forming processes including the trimming and shaping.

Therefore, after the blank has passed this continuous press forming processes, it still needs to be trimmed and shaped by another press or by the same press with another die assembly.

Although by following this way it is possible to combine some of the processes as a single process to thereby reduce the total number of the processes required, it nevertheless is unable to combine all of the processes as a single one and hence there still remains the aforesaid shortcomings.

Furthermore, since the conventional combination die assemblies possess counter action springs, which, after the lower dies have been under the downward punching force, are to drive the lower dies or punching pins into action by the resilient recovery force thereof, there requires thus the power needed for the work to be a force capable of overcoming the resisting force of the said springs and capable of subjecting the blank to press forming. For this reason, the punching machine used also increases in size, while the die assemblies to be able to resist the punching force of the machine must also increase in thickness and in size thereby leading an increase in cost of production in the equipment and die assemblies.Besides, owing to the related limitation in the stroke and construction of the crease-resist piece of pressed material driven by cams, the stroke of the slide driven by the crankshaft in the conventional multi-action press is unable to perform deeper stamping. For instance, in a conventional multi-action press generally using combination dies if the stroke is 200 mm, the finished products thereof will only be about 40% of the depth or the height, that is, SO mm, and the rest of the stroke will have no action. There is thus hardly any possibility to accomplish continuously deep drawing of a long cylinder having reached a depth of more than half of the stroke of the slide with a conventional press.

Progressive die assemblies have been commonly applied to the press operation in the progressive press forming of the motor iron cores and others. However, use of a largesize press or hydraulic punching machine of a larger stroke and tonnage in cooperation with horizontally arranged progressive dies formed by combination of a plurality of sets of die assemblies must be a possible way. This has in fact proved to be so and by mere arrangement of die assemblies a factory can thus be able to solve all the problems and without having to change the conventional machinery. Although it seems to be all right, the progressive-die forming method is, nevertheless, suitable only for shallow-recessed products and not for deep-drawing processing.

In view of the foregoing disadvantages in the prior art, the inventor conducted a long-time research, experiment and modification and has now been able to accomplish a punch press especially for deep drawing operation.

Accordingly, one object of the present invention is to provide a punch press for deep drawing having 2 vertically arranged mutually coupled crankshaft cam units and an upper sliding piece driven by the two units to move up and down and a lower slide assembly arranged in upper and lower tiers to be capable of moving vertically, and which in a single-action stroke is capable. of accomplishing a series of processes of blanking, one-time to multi-time press forming, trimming, shaping and stripping in a material held on the concentric die set.

A further object of the present invention is to provide for deep drawing a punch press, which is simple in construction and easy to manufacture, and which uses less power and is capable of accomplishing in a single acting all the performances of multi-time press forming, trimming, shaping and stripping in a blank to be effective in time and in work.

A further object of the present invention is to provide a deep-drawing punch press capable of forming in a single action press stroke a container-shaped component having a depth nearly reaching the deepness of that stroke length while the tonnage or power required being far less than the conventional punching machine or hydraulic press using combination die set or progressive die set.

An additional object of the present invention is to provide a deep-drawing punch press in which since a stamped product from the blank to the finished product can be accomplished in continuity on the same punching machine and with the same die set, there is thus no loss of time for waits of work and for transfer and also no cooling by the cold air, and since the product is accomplished on the same axis and under the same processing conditions it is possible to secure deep-drawn products of high precision and fine quality.

Another object of the present invention is to provide a deep-drawing punch press capable of sufficiently and effectively utilizing up to 90 percent of a press stroke to thereby accomplish the deep-drawing operation of a range of depth of processing that can never be attained by any conventional punching machines of a type having the same stroke.

Further objects and advantages of the invention will become apparent from a consideration of the drawings and ensuing description of it.

In the drawings: FIG. 1 is a partly sectional schematic front view of a deep-drawing punch press in one embodiment of the present invention; FIG. 2 is a schematic lateral view of the punch press; FIG. 3 is a perspective view of the upper crankshaft cam mechanism of the punch press; FIG. 4 is a perspective view of the lower crankshaft cam mechanism of the punch press; FIG. 5(A) and 5(B) are sectional views of one embodiment of the die set used in the punch press; FIG. 6 is an analytical diagram of action of the upper and lower crankshaft cam mechanisms; and FIG. 7 is an analytical chart of action of the stroke and time of the upper and lower crankshaft cam mechanisms.

As shown in FIGS. 1 and 2, the deep-drawing punch press of the present invention comprises principally an upright post C-type frame 1, a driving unit 2 mounted on the frame 1, drive means 3located on the side wall of the frame 1, an upper crankshaft cam mechanism 4 mounted in the front upper portion of the frame 1, a lower crankshaft cam mechanism 5 mounted in the front lower portion of the frame 1, an upper slide 6 couplingly located at the bottom of the upper crankshaft cam mechanism 4, a lower slide set 7 couplingly located on the top of the lower crankshaft cam mechanism 5 and arranged spaced-apart in tier, and a fixed bed 8 mounted on the top of the lower slide set 7.

The frame 1 is formed of steel plate or steel frame construction element having at the forward slightly central region a working clearance and being door-like when viewed from the front side and C-shaped when viewed from the lateral face.

For the driving unit 2, the present embodiment utilizes a stepless speed change motor, which is firmly mounted on top of the frame 1. However, it will be appreciable if other prime motor is used and mounted at any other location on the frame that is suitable for the drive or is'mounted even at a place away from the frame l. Since this is easily conceivable by a general person skilled in the art, it will not be dealt with in detail here.

The drive means 3 is located on the two side walls of the frame 1 for use to transmit the rotary force coming from the driving unit 2 to the upper and lower crankshaft cam mechanisms 4, 5, comprising: a drive belt wheel 31 directly connected to the main shaft 21 of the driving unit 2, an upper driven belt wheel 33 driven by the belt wheel 31 by means of driving belt 32 and acting also as a flywheel , a lower driven belt wheel 35 driven by the belt wheel 33 by means of a driving belt 34 and acting also as a flywheel, a brake clutch 36a disposed between the upper belt wheel 33 and its drive shaft 30a, a brake clutch 36b disposed between the lower belt wheel 35 and its drive shaft 30b, an upper gear cluster 37 driven by the upper driven belt wheel 33 and a lower gear cluster 38 driven by the lower driven belt wheel 35.The upper gear cluster 37 , in turn, includes a drive gear 37a fixed to the drive shaft 30a of the upper belt wheel 33, a driven gear 37b fixed to an intermediate shaft 39a to be driven in meshing engagement with the drive gear 37a, a further gear 37c similarly fixed to that intermediate shaft 39a, and anultimate gear 37d fixed to one end of a crankshaft 41 of the upper crankshaft cam mechanism 4.The lower gear cluster 38, on the other hand, includes a drive gear 38a fixed to the drive shaft 30b of the lower driven belt wheel 35, a driven gear 38b mounted on the intermediate shaft 39b to be driven in meshing engagement with the gear 38a, a gear 38c mounted on the same intermediate shaft 39b, a gear 38d mounted on another intermediate shaft 39c to be driven in meshing engagement with the gear 38c, a gear 38e mounted on the same shaft 39c and anultimate gear 38f mounted on one end of a crankshaft 51 of the lower crankshaft cam mechanism 5 to be driven in meshing engagement with the gear 38e.In this arrangement, when motor of the driving unit 2 turns around in the clockwise direction, the upper crankshaft cam mechanism 4 rotates deceleratingly in the same direction through the retarding drive of the upper gear cluster 37 in the drive means 3, whereas the lower crankshaft mechanism 5 rotates deceleratingly in the opposite direction through the retarding drive of the lower gear cluster 38. In the present embodiment, the upper gear cluster 37 is located on the upper portion left side of the frame and the lower gear cluster 38 is located on the lower portion right side of the frame 1. It is equally possible if, the two gear clusters 3i, 38 are arranged on the same side or the two change their position mutually. Again, in accordance with necessity in the design the ratio of speed of the upper crankshaft cam mechanism 4 and the lower crankshaft cam mechanism 5 should be that the former is greater than the latter and, in general, a ratio of 2:1 to 8:1 is the most appropriate. In addition, it is also possible if, in place of the gear device 3 a chain wheel-and-belt device or any other potential driving means is used.

The upper crankshaft cam mechanism 4 is disposed on the front upper portion of the frame 1 and is capable of rotation by the drive of--the upper gear cluster 37. - As shown in FIGS.

1 and 3, this mechanism 4 comprises a crankshaft 41 having at one end the aforesaid ultimate gear 37d fitted thereto, a downwardly extending connecting link 43 rotatably mounted on the crank pin 42 of the crankshaft 41 to be perpendicular with the crankshaft 41, a bolt stick 44 adjustably connected to one end of the connecting link 43 and a pair of cams 45, 45 disposed symmetrically spaced-apart on the crankshaft 41 on the two sides of the crank pin 42.

The lower crankshaft cam mechanism 5 is located at the front lower part of the frame 1 to be just vertically opposite to the upper crankshaft cam mechanism 4 and is rotatable by the drive of the lower gear cluster 38. As shown in FIGS. 1 and 4, this cam mechanism 5 comprises a crank shaft 51 having at one end fixed with the above-said ultimate gear 37f, an upwardly extending connecting link 53 rotatably mounted on the crank pin 52 of the crank shaft 51 to be perpendicular to the crank shaft 41, a lower push rod 54a rotatably connected to one end of this connecting link 53, a central push rod 54b connected to the upper end of the lower push rod 54a by a ball attachment 50 and several pairs of cam sets 55, 56 and 57 having the connecting link 53 as center arranged symmetrically in sequential order from outside inwardly on the crank shaft 51.In the present embodiment, the cam sets include a pair of first cams 55, 55 of small shape disposed on the two inner side walls of the crank shaft 51 close to the frame, a pair of second cams 56, 56 of large shape located to the inner side of the said pair of the first cams 55 and a pair of third cams 57, 57 of the largest shape being closely adjacent the second cams 56, 56 on the left and the connecting link 53 on the right. In reality, however, the number of cam sets required may be varied depending on the number of deep drawing processes and also the kind, quality and thickness of the materials used. In addition, one pair of the third cams 57 are provided at the upper ends of the parts with longest diameter closely adjacent the inner sides thereof with a pair of projections 58, 58, the function of which will be hereinafter described.

The upper slide 6 is vertically slidable along the slide rails 11 at the upper part of the frame 1 and is disposed at exactly the lower portion of the upper crankshaft cam unit 4.

This slide 6 is joined with the connecting link 43 to form a single body by a ball attachment formed by a ball-and-socket member 61 disposed in a recess on the upper center of the slide and a ball head 44a at the lower end of the bolt stick 44. Ther is next a pair of springs 62 located in the recess at the p ce on the two sides of the ball attachment. On the lower end of the springsfi62 is a contact plate 64 and below this contact plate 64 there is connected a push rod 65 capable of connecting to a push plate 94a which will be described later.On top of the slide 6 located on the two sides of the recess there are a pair of spaced apart pressure levers 63 being arranged symmetrically with the bolt stick 44 in the center, the pressure levers 63 having at the upper end each a roller 63a to be exactly opposite to and cooperating with the aforesaid cams45.

The lower slide set 7 is mounted at the front lower part of the frame 1 and is located on the top of the lower crankshaft cam unit 5. This slide set 7 comprises: an upper bed plate 71 having the two ends attached to the two inner side walls of the frame 1, a lower bed plate 72 having the two ends likewise attached to the two inner side walls of the frame 1 to be vertically opposed in a distance from the upper bed plate 71, two parallel upright side plates 73, 73 located vertically between the upper and the lower bed plates 71, 72, a plurality (in the present embodiment, the number is 4) of appropriately spaced-apart slides 74a, 74b, 74c, 74d in several tiers and being vertically slidable along the two side plates 73 to be located between the upper and the lower bed plates 71, 72,and a plurality of pairs (in the present embodiment, the number of pairs is 4) of push rods 76a, 76b, 76c, 76d being different in length and having the upper ends connected as shown to the aforesaid slides 74a to 74d and the lower ends each provided with a roller 75 to be rotatably in contact with the cam surface of each pair of the cams 55, 56, 57 in the lower crankshaft cam unit 5. Furthermore, the foregoing push rods 76d are in contact with the inner sides of the cam surfaces of the third cams 57 and are located exactly on the rotation tracks of the projections 58.

Therefore, when cams 57 rotate, lower ends of these push rods 76d will be carried over the projections 58 and be lifted up.

The fixed bed 8 is located on the upper bed plate 71 and is opposed vertically with the upper slide 6, (i.e. the moving bed) whereas, the dies 9 (including the upper and the lower dies), represented in FIG. 1 by the imaginary line, are set-up on the moving bed 6 and the fixed bed 8.

As shown in FIG. 1, the foregoing central push rod 54b passes slidably between the upper and the lower bed plates 71, 72, the fixed bed 8 and the respective slides 74a to 74d whereas, the tip thereof projects out of the bed 8. The push rods 76a likewise pass slidably between the lower bed plate 72 and the respective slides 74d, 74c, 74b whereas, the tips thereof are pushed against the slide 74a of the first tier.

The push rods 76b pass slidably between the lower bed plate 72 and the respective slides 74d, 74c whereas, the tips thereof are pushed against the slide 74b of the second tier.

The push rods 76c pass slidably in the lower bed plate 72 whereas, the tips thereof are pushed against the slide 74d of the fourth tier. The push rods 76d in their turn pass slidably between the lower bed plate 72 and the slide 74d whereas, the tips thereof are pushed against the slide 74c of the third tier.

One example of the combination die set 9 adapted for use with the machine of the present invention is shown in FIG. 5 and is comprised of an upper die portion 9A and a lower die portion 9B. The upper die portion 9A includes a multiplicity of concentrically fitted overlap dies 91, 92, 93, 94 decreasing progressively in diameter of the die cavity from large to smaller and also from shallow to deeper in a from-below-upward manner according to the deep-drawing processes required in the deep-drawing products. In the cavity of the die 94 of the uppermost tier there is further provided a cutting die 95 capable of moving up and down inside the die 94 with the pressure of the push plate 94a and the push rods94b.The lower die portion 9B in turn includes a ring outer die 96, a ring sleeve die 96a fitted over the outer circumference on the upper end of the outer die 96 and projecting slightly upwardly and the inner circumferential margin thereof working as an edge for shearing the processing materials and a set of ring stamping dies 97a to 97d corresponding to the respective dies 91 to 94 of the upper die portion 9A and being arranged in a centre-fitting manner from outside inwardly, and a punch pin 98 firmly located at the tip of the central push rod 54b. Attached at the lower ends of the stamping dies 97a to 97d there are a plurality of push rods 99a to 99d extending downwardly.These push rods 99a to 99d have the lower ends thereof pushed respectively against the upper sides of the slides 74a to 74d, however, the slides 74c and 74d required by the push rods 99c and 99d have changed places, that is, push rod 99c pressing against the slide 74d and the push rod 99d against the slide 74c.

In the following, working condition of the deep-drawing punching press of the present invention during the operation is described.

When the drive machine 1 is initiated, the upper and lower belt wheels 33, 35 are driven to rotate synchronously and in the same direction by the drive belt wheel 31 and the driving belts 32, 34. Consequently, the upper crankshaft cam unit 4 upon drive by the upper gear cluster 37 (including the gears 37 to 37c) is moved to decelerate and to rotate with the belt wheel 33 in the same direction and at a lower speed. On the other hand, the lower crankshaft cam unit 5 upon drive by the lower gear cluster 38 (including gears 38a to 38f) is moved to decelerate and to rotate in an opposite direction and at a lower speed with the belt wheel 35.Since in the present embodiment, the ratio of speed of the upper and the lower crankshaft cam units 4 and 5 is set at 4:1, therefore when one revolution of the upper unit 4 is 3600, the lower unit 5 will perform only one quarter revolution of 900. In fact, according to workpieces and the production condition this ratio of speed is chosen to be any suitable ratio and as to the working relation between the two it will be dealt with in detail later.

Referring again to FIGS. 5 through 7, the operating condition of the punching press of the invention is described.

When the upper crankshaft cam unit 4 is turned 1800 round from the upper dead point a to the lower dead point b, the upper die 9A that is fitted on the upper slide 6 is moved to descend together with the slide 6 along the slide rails 11 by the coupled action of the connecting link 43 and the screw bolt 44 and also to shear off the work material W disposed on the lower die 9B in the condition as shown in FIG. 5A. When the slide 6 has fallen to the lower dead point, the longdiameter ends of the pair of cams 45 on the crankshaft 41 are exactly pressed against the rollers 63a at the upper ends of the two pressure levers 63 of the slide 6.At the same time, the air type brake coupling or clutch 36a of the belt wheel 33 for controlling the airflow line by means of magnetic valve switch (not shown) automatically cuts off the coupling relation and movement of the crankshaft unit 4 is stopped whereby the slide 6 is held pressed at the position of lower dead point b.

As above described,when the upper crankshaft unit 4 has turned round from the upper dead point a to the lower dead point bt simultaneously the lower crankshaft unit 5 rotates upwardly in the opposite direction from the lower dead point c.

Since in the present embodiment, the ratio of speed of the upper and the lower crankshaft units 4, 5 is 4:1,therefore, when the upper crankshaft unit 4 has rotated 1800 to the lower dead point b, the lower crankshaft unit 5 is turned 450 round from the lower dead point c only. Thereafter, when the upper crankshaft unit 4 has stopped rotation because of the action of the clutch 36a, this lower crankshaft unit 5 nevertheless continues to rotate because of the clutch 36b still maintaining the coupling action. At this time, the longdiameter cam surface of the first cam 55 by means of the push rod 76a is moved to push the slide 74a of the upper tier upwardly.The slide 74a by means of the die set push rod 99 in turn pushes the first punching die 97a upwardly and enters the die cavity of the upper die 91 thereby exerting a first stamping to the work material W. Now, the stroke of the punching die 97a is S1. As the crankshaft unit 5 continues to rotate, soon after the punching die 97a has completed the first pressing, the long-diameter cam surface of the second cam 56 by means of the push rod 76b, the slide 74b of the second tier and the push rod 99b pushes the second punching die 97b upwardly into the upper die 92 thereby exerting a second stamping to the work material W having already undergone first pressing.Now, the stroke of the punching die 97b is Following the process, the long-diameter cam surface of the third cam 57 by means of the push rod 76c, the slide 74d of the fourth tier and the push rod 99c pushes the fourth punching die 97d together with the third punching die 97c overlapping the die 97d upwardly into the upper die 93 thereby exerting third stamping to the work material W.Now, the stroke of the punching die 97c is s3. At the same time, it follows that because the crankshaft pin 52 of the lower crankshaft 51 has entered the position close to the dead point d on the above, the central punch pin 98 by means of the connecting link 53 and the push rods 54a, 54b is next pushed into the upper die 94 thereby exerting a fourth stamping to the work material W until the crankshaft has risen to the upper dead point d and performed one stroke S.

During the same time of this action, the projection 58 of the cam 57 which is higher than its cam surface pushes against the push rod 76d and by means of the slide 74c of the third tier and the push rod 99d is moved to push the third punching die 97c into the cutting die 95 of the upper die 94 against the force of the spring 62 and in cooperation with cutting edges of the two dies to exert trimming action on the stamped piece. At the same time, the central punch pin 98 continues to push the stamped piece W, which has been trimmed, into the upper die 94 to thereby perform the shaping action in the condition as shown in FIG. 5B. During this time, the lower crankshaft unit 5 has risen to the upper dead point d and begins to rotate towards the lower dead point c to perform movement of the other half rotation.

At the same moment as the lower crankshaft unit 5 has risen to the upper dead point d, because of the action of the electromagnetic valve (not shown) in coordination with the lower crankshaft unit 5 the upper crankshaft unit 4 allows the clutch 36a to be coupled again. Consequently, the upper crankshaft unit 4 begins to rotate from the lower dead point b to the upper dead point a and by the upper slide 6 carrying the upper die 9A to rise by means of the connecting rod 43 and the screw stem 44, to return to the original position.

On the other hand, through the clutch disengaging to stop moving the lower crankshaft unit 5 is also moved to rotate from the upper dead point d to the lower dead point c, as a result of which, through an action opposite to the above the slides 74a to 74d descend following the descent of the push rods 76a to 76c and the punching dies 97a to 97d also come down one by one. In the same time, through the descent of the connecting link 53 and the push rods 54a, 54b the central punch pin 98 is also moved down.Finally, when the individual punching dies 97ato 97d and the punch pin 98 are received in the lower die 96 and at the same time, the product from the upper die 94 that has been subjected to deep-drawing is pushed downwardly out by the recovery force of the spring 62 through the pressing of the push rods 65, 94b and the push plate 94a, stripping action is thus completed and dies are then returned to the condition as shown in FIG. 5A. The upper and lower crankshaft units 4, 5, in the meantime, from their respective positions of the upper and lower starting points a and c complete one cycle of operation.

The above embodiment is described in respect of the condition of operation on a multiplicity of processes of shearing, stamping in four times, trimming, shaping and stripping of a work material accomplished in one single performance. It must have to be pointed here that the present invention is not limited in its application to the present embodiment and for stamping of those products required only two times or three times of the stamping the punching press of the present invention can still be used freely without having to make any changes in the crankshaft units 4, 5.

For instance, in the forming of a product with three times of stamping this can be performed with the machine by removal of the two push rods 76a on the outer sides so that movement of the first cam 55 will not carry the first slide 74a. In the forming with two times of stamping, the lower push rods 76a , 76b can be removed so that both the first and second cams 56, 56 will not move slides 74a, 74b. It is, of course, necessary that the die set 9 for use should comply with the suitable combination dies to be utilized according to necessity.

According to a further feature of the present invention, if job requires the present punching press may also be used for assisting generally the processes of stamping and shearing of, such as, core plates of the motor rotor or stator or generally the single-forming or shallow drawing processes.

In such a case, all that is required is just to release the lower clutch 36b from the coupling condition and to maintain the upper clutch 36a in the coupling condition whereby the lower crankshaft unit 5 is maintained at the idle state while only the upper crankshaft unit 4 keeps on the continuous back-and-forth movement. Like in common crankshaft press or a double action press, the press of the present invention can perform the general processes of a press and is thus capable of increasing the field of application of the present invention, while those common specific machines, on the other hand, are frequently limited by the mechanism or design and is suitable for single use only.

Owing to the composition as described above, the punching press of the present invention accomplish the deep-drawing procedure completed in one continuity of a series of progresses from the shearing, multiple press-forming, trimming, shaping to the stripping in one cycle of operation un-accomplished before with only a single machine. In addition to that, the work piece from delivering into the machine to the forming and ejection of the finished product is completed in the same die set and in one short operating stroke. Hence, there will be no loss of time for waits of work or materials during the operation and also no humidity effect for having to be submitted to the cooling of surrounding air.It is also possible to avoid any hardening of the process induced by the long-duration processing and to avoid any accumulative error in precision accuracy of the processing caused by having to pass through different machines, different die sets and different processes. In this way, it is possible to raise the efficiency of production by several times and that the finished product so obtained has a high precision and fine quality and the surface is extremely smooth and aesthetic.

Again, the power required by the punching press of the present invention is far more less than that required in producing the same deep-drawn product by the conventional machines and as such there can be a save in energy resources and also the possibility to use the relatively thinner and smaller materials for the die sets whereby to save the cost of die making and to extend life of the die. Besides, it is possible to use full the operating stroke of the crankshaft unit of the invention and the length of use may reach approximately 90% of the stroke, which is far more than twice the length of only about 40% that can be most reached by the conventional presses.Hence, it makes possible a decrease in the volume of the machine and at the same time, makes possible for the machine to be capable of accomplishing within the same machine the press forming procedure of a depth of processing that can not be achieved by the conventional presses of the same size.

With attendant advantages of being simple in construction, easy to operate, low in the cost and capable of being used as a general press at any time, the punching press of the present invention is thus of a novel, unique and practical useful form.

It is to be understood that the form of the invention herein shown and described is to be taken as merely a preferred example of the same, and that the invention may be otherwise modified within the scope of the invention. For instance, in lieu of the above-mentioned drive means there can be employed devices such as chain wheel, chain belt or gear, in lieu of the upper and lower gear clusters, the gear series of other type of combination with rotation in the same direction or the opposite direction and in lieu of the spring device inside the upper slide, the hydraulic means or hydraulic spring compound mechanism.

Claims (9)

1. A deep-drawing punch press, comprising: a frame, a driving unit mounted On said Tralle, a drive mechanism mounted on said frame and driver by said driving unit, an upper crankshaft cam mechanism disposed transversely on an upper part of said frame and driven by said drive mechanism, a lower crankshaft cam mechanism disposed transversely on a lower part of said frame to be parallel with said upper crankshaft cam mechanism and also being driven by said drive mechanism to rotate at a speed of rotation slower than that of said upper crankshaft cam mechanism, an upper slide below the crankslwa~t cf to said upper crankshaft cam mechanism and connected to one end of a connecting rod whereby said upper slide may be driven by said upper crankshaft cam mechanism to move back and forth vertically along a slideway provided by said frame, a lower slide plate set above the crankshaft of said lower crankshaft cam mechanism and disposed spaced-apart in tiers and vertically opposed to said upper slide, said lower slide plates being slidably joined to respective cams of said lower crankshaft cam mechanism by way of the lower ends of a push rod set and being capable of moving back and forth vertically at different time intervals by the drive of said lower crankshaft cam mechanism, and a bed fixed by its lower part above the upper part of said lower slide plate set to be directly opposed to said upper slide.

2. A deep-drawing punch press according to claim 1, wherein said drive mechanism includes two sets of speed reduction gears of different speed ratios to enable the speed of rotation of said upper crarzkshaft cam mecl!t1Y!ism to be greater than the speed of rotation cf said 'owe crankshaft cam mechanism.

3. A deep-drawing punch press according to claim 2, wherein the ratio of the speed of rotation of said upper crankshaft cam mechanism to that of said lower crankshaft cam mechanism is between 2:1 to 8:1.

4. A deep-drawing punch press according to any preceding claim, wherein said upper crankshaft cam mechanism includes its said crankshaft, said connecting rod mounted on a crankshaft pin of said crankshaft and a pair of spaced-apart, symmetrically-arranged cams located on said crankshaft at the two sides of said connecting rod.

5. A deep-drawing punch press according to any preceding claim, wherein said lower crankshaft cam mechanism includes its said crankshaft, a connecting rod mounted on a crankshaft pin of said crankshaft and at least two pairs of cams arranged symmetrically and progressively from the two sides of said crankshaft pin outwardly in sequence from large to small in a step-like manner.

6. A deep-drawing punch press according to any preceding claim, wherein said lower slide plate set includes a plurality of slides arranged in tiers between upper and lower bed plates mounted spaced-apart below said fixed bed, said slides being capable of being lifted up and lowered down readily by the up-and-down movement of said push rod set, with each of said push rods having one end joined to a cam of said lower crankshaft cam mechanism and the other end pushing on one of said slide plates.

7. A deep-drawing punch press according to any preceding claim, wherein at least said upper crankshaft cam mechanism is provided with a brake clutch for controlling the movement of said upper crankshaft cam mechanism.

8. A deep-drawing punch press according to claim 7, wherein when said connecting rod driven by said upper crankshaft cam mechanism is lowered to a lower dead point, said upper brake clutch becomes automatically released and thereby causes said upper crankshaft cam mechanism to be immovable until such time as said lower crankshaft cam mechanism is lifted up to its highest position, whereupon said upper brake clutch becomes once again coupled and said upper crankshaft cam mechanism is rotated to an upper dead point.

9. A deep-drawing punch press substantially as hereinbefore described with reference to the accompanying drawings.