US3844157A

US3844157A - Machine for applying force

Info

Publication number: US3844157A
Application number: US00267596A
Authority: US
Inventors: H Bachmann
Original assignee: Langenstein and Schemann GmbH
Current assignee: Langenstein and Schemann GmbH
Priority date: 1971-06-30
Filing date: 1972-06-29
Publication date: 1974-10-29
Anticipated expiration: 1991-10-29
Also published as: DE2132377C3; DE2132377B2; IT956928B; DE2132377A1; JPS5119630B1; FR2144364A5; GB1399377A

Abstract

A press for applying force to a workpiece, having a piston-andcylinder arrangement connected to a wedge which actuates the ram. The piston-and cylinder arrangement includes two pistons selectively displacable for either pressing, or for impacting the workpiece. Weights are arranged on a spindle threadingly received in the wedge for driving the wedge, on the flywheel principle.

Description

United States Patent [1 1 Bachmann 451 Oct. 29, 1974 1 MACHINE FOR APPLYING FORCE [75] Inventor: Horst Bachmann, Rodental, Germany [73] Assignee: Langenstein & Schemann Aktiengesellschaft, Coburg, Germany [22] Filed: June 29, 1972 [21] Appl. No.: 267,596

[30] Foreign Application Priority Data June 30, 1971 Germany 2132377 [52] US. Cl 72/452, 72/454, 100/291 [51] Int. Cl B2lj 11/00 [58] Field of Search 72/452-454,

72/443, 445, 449, 405, 441; 100/291, 270, 273, 289, 271; 10/11 T, 12 T, 12.5, 76 T [56] References Cited UNITED STATES PATENTS 3,101,632 8/1963 Hoyt 10/12.5

3,122,033 2/1964 Riemenschneider 72/441 3,512,476 5/1970 Georg 72/454 3,595,163 7/1971 Baumann 72/454 FOREIGN PATENTS OR APPLICATIONS 524,628 5/1931 Germany 72/452 7,550 0/1838 Great Britain 100/291 Primary Examiner-C. W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firm-Holman & Stern [57] ABSTRACT A press for applying force to a workpiece, having a piston-and-cylinder arrangement connected to a wedge which actuates the ram. The piston-and cylinder arrangement includes two pistons selectively displacable for either pressing, or for impacting the workpiece. Weights are arranged on a spindle threadingly received in the wedge for driving the wedge, on the flywheel principle.

5 Claims, 7 Drawing Figures SHEEIIOF 4- PATENTED URI 2 91974 AH 45 M PATENTEDHIII 2 i914 SHEET 3 B 4 3.844; 1 57 1 MACHlNEEQB APBLXlNG F RCE The invention relates to a machine for applying force to a workpiece optionally for both pressing or stamping operations. The machine may incorporate a press mechanism organized as a hydraulic piston-cylinder system, and a percussion mechanism, for a ram equipped with a percussion tool.

It is an object of the present invention to provide a deforming machine which may be operated as a hydraulic press in such manner that the ram can not only be advanced rapidly towards a workpiece, but begins the pressing operation immediately, without a decrease in speed, when the tool comes into contact with the workpiece, and during the transition between the approach stroke to the pressing stroke there is relatively little or no decrease in speed of the ram stroke. To this end, the invention comprises a wedge acting on a ram, which wedge preferably is acted upon or operated by a flywheel-spindle type system arranged with a longitudinal spindle axis extending transversely to the direction of movement of the ram, which spindle may be optionally displaced by means of the hydraulic pistoncylinder system acting as a pressing mechanism, or by means of a percussion mechanism a pressing tool and a stamping or impact tool are preferably incorporated side-by-side.

ln particular, the invention provides a machine for applying force to a workpiece, comprising a frame; a ram guided in the frame for delivering the force at one end thereof; a wedge having mutually inclined first and second surfaces, the first surface being arranged to slide on the ram at its other end, the second surface being guided in the frame; a threaded spindle parallel to said second surface and threadingly received in said wedge; and a piston-andcylinder means operative in a direction parallel to the spindle and disposed on the frame on the opposite side of the wedge from the spindle-driving means, but connected to the wedge for driving it. Preferably the machine includes piston-andcylinder means comprising a first cylinder fixed to a frame with a first piston for applying sustained pressure to the wedge, and a second cylinder with limited freedom of movement with respect to the frame and a second piston of smaller area than the first piston, for applying percussive blows to the wedge; preferably the machine first piston is hollow as in said second cylinder and there may be a source of fluid under pressure for powering the first piston and first cylinder. Preferably the machine comprises a pressing tool and a percussion tool arranged side-by-side to be driven by the ram, and a table slidable transversely to line joining the pressing tool and the percussion tool; the table carrying dies for co-operating with said tools.

The invention will now be described, by way of exam ple only, with reference to preferred embodiments illustrated in the accompanying drawings, in which:

FIG. 1 is a diagramatic section through a spindle press showing two hydraulic driving units and a fixed Spindle;

FIG. 2 is a fragmentary, enlarged diagramatic section through a spindle press comprising two hydraulic driving units and an axially dispaceable spindle;

FIG. 3 is a fragmentary, enlarged diagramatic section through another spindle press comprising two hydraulic driving units and an axially displaceable spindle;

FIG. 4 is a fragmentary, enlarged diagramatic section through a spindle press comprising two hydraulic driving unitsand an electric motor;

FIGS. 5 and 6 is a diagramatic view of two separate tool units for pressing and for forging on a sliding table; and

FIG. 7 is a diagramatic plan view of a sliding table and tool piece handling systems mechanism.

The spindle press shown in FIG. I comprises an anvil or platen l which carries a lower tool system 2, in alignment with which is an upwardly and downwardly (reciprocatable) displacable upper tool system 3 fastened to a ram 4', the latter being guided on two opposed sides. The short side 5' of a triangular wedge 5 rests on an upper horizontal surface of the ram 4 and the longer side 5" bears against an oblique face of a frame head 6. Two hydraulic piston-cylinder arrangements 7 each act at one end on the ram 4 and at the other end against the frame head 6 and function to draw the ram upwards after it has been displaced downwards by means of the wedge 5. The wedge 5 is not mechanically coupled to the ram 4, however, such a connection could be incorporated.

At the projected-apex or sharpest angle of the wedge 5, a spindle 8 is journalled which is rotatable but not axially displacable in a bearing .9 within the frame head 6. The spindle 8 extends at an acute angle (not to the direction of displacement of the ram 4, is parallel to the hypotenuse or side 5" of the wedge 5. The spindle passes through a bore of the wedge 5 and through a feed nut 10 fixedly arranged within the wedge. During rotation of the spindle 8 (by means not shown), the wedge 5 will move along the spindle within head 6 and thus apply vertical components of force between surfaces 5', 5".

Opposite the acute apex or sharpest angle of the wedge 5, a cylinder 11 is fixed to the frame head 6. A hollow piston 12 is limitedly displaceable in the cylinder ll, protrudes out of the cylinder in the direction towards the wedge and has an axial liner. In the liner ll of the hollow piston 12, which also acts as cylinder, is a displacable piston 13 which is connected to the wedge 5 by means of a piston rod 13. The center lines of the cylinder 11, hollow piston 12 and piston 13 are arranged parallel to (in fact, colinear with) the axis of the spindle 8.

Fluid (preferably water under pressure (from a common source, not shown) may be fed into the hollow space of the hollow piston 12 through an axial opening 14 in the end of the cylinder 11, the wedge 5 will be advanced rapidly by the piston 13 and rod 13, the ram 4 thereby will be rapidly displaced downwards as in this case function as a spindle impact press. The rapid advancement of the wedge 5 causes the spindle 8 to rotate in feed nut 10 despite the axially journalling thereof in the bearing 9. The fixed arrangement of the feed nut 10 in the wedge and the thread of nut 10 is such that rotation of the spindle 8 will also move the wedge. To displace the ram as in a hydraulic press, both the hollow piston 12 as well as the piston 13 are acted upon (conveniently by the same pressure fluid also from the common source) through opening l4 and another opening 15 in the end of the cylinder H. The hollow piston 12 and the piston 13 are retracted by being acted upon by fluid under pressure at the side adjacent or towards the wedge 5, the piston retracting the wedge 5 and the fluid acting upon the piston 13 at the side facing towards or adjacent the wedge being fed in under pressure through conduit means not shown. The piston 13 is also moved back by a component of force when the ram 4 is moved upwards by the piston-cylinder arrangements 7. The openings 14 and are connected to a common pump assembly which is not shown, through appropriate valves and control elements (not shown, but well known in the art).

At the side furthest from the cylinder 11, the spindle 8 projects out of the frame head 6 and carries a flange 16 on the projecting extremity. Centrifugal weights l7,

18 are rotatably arranged on the spindle 8, one at either side of the flange 16 (much as in a friction clutch). The centrifugal weight 17 at the side facing the head frame 6 carries bolts which project through the other centrifugal weight 18. On the projecting extremities of the bolts are situated springs which urge the two centrifugal weights against the flange 16. In thisway, rotation of the spindle 8 (and hence of the flange 16) tends to drive the centrifugal weights l7, 18. In this case, the

centrifugal weights should separate from the spindle whilst there is slipping, to'prevent an overload on the press, on the flywheel principle, slipping occurs as soon as the slipping torque is reached or a particular pressing force is generated, this is .the rated power of the press, as a rule.

The form of embodiment according to FIG. 2 differs from that according to FIG. 1 in that the feed nut 10 is fixed in the head frame 6 (rather than in the wedge 5), and in that the spindle 8 moves bodily axially, taking with it the wedge 5.

In FIG. 3, by contrast to FIG. I, the centrifugal weights l7, l8 and the spindle 8 are situated at the thicker side of the wedge 5, while the percussion mechanism and the press mechanism are situated on the side of the head frame 6 at the sharp end of the wedge 5. By contrast to FIG. 1, a massive piston 19 coupled to the wedge 5 is displaceable within the cylinder 11 of the press mechanism. The hollow piston 12 of FIG. 1 has become (in the FIG. 3 embodiment) a cylinder beyond the cylinder 11. A rod 20, connected to the piston displacable within the hollow piston 12, projects through the end of the cylinder 11 and acts on the piston 19. The form of embodiment according to FIG. 3 may be modified (compared with FIG. 2) in such manner that the spindle 8 is not axially displaceable, more like FIG. 1.

By contrast to the form of embodiment according to FIG. I, the centrifugal weights I7, 18 may be driven by means of an electric motor 21 via a connection that is not shown (FIG. 4). The slip coupling between the centrifugal weights l7, l8 and the spindle is switchably arranged moreover, so that the centrifugal weights may be coupled to the spindle and uncoupled from the same I at will.

The presses shown in FIGS. 1 to 4 are appropriately equipped as shown in greater detail in FIGS. 5 to 7. The

tool system 3. arranged on the ram,4 comprises a pressing tool (e.g. an extrusion moulding punch) 22 and another punch 23 preferably for stamping or forging (i.e.. a percussion tool). said tools are arranged one beside the other. The lower tool system 2 has, correspondingly, an extrusion moulding die 24 and another die 25. The lower tool system 2 is mounted on a sliding table 26 which is displaceable in a direction at right angles to the direction of displacement of the ram 4. Ejector pins 27 are situated in alignment under the ram 4, by means of which it is possible to lift a long workpiece 28, projecting through the sliding table 26, into the extrusion moulding die 24 or into the die 25, when the dies are positioned beneath the ram 4.

According to FIG. 7, the sliding table 26 carrying two pairs of dies 24, 25 is situated on guide rails 33 of a fixed support 29. Handling mechanisms 30 each comprising two

pincers

31, 32 are situated one at each side (in the path of sliding) of the sliding table 26. The one handling mechanism 30 can be used to feed a blank in by means of the one pair of pincers 31, the other pair of pincers removing a finished workpiece from the finish pressing die 25. The sliding table 26 would then displaced towards the other handling mechanism 30, so that the blank inserted could be extrusion moulded. When the sliding table is pushed back again, the extrusion moulded part would be repositioned by means of the pair of pincers 32 in order to be inserted under the ram for the purpose of finish forging. Another blank could be fed in during the repositioning action. During the repositioning and feeding actions, a workpiece or blank fed in by the other handling mechanism 30 could be worked by means of the ram. Prior to the displacement of the sliding table 26, which follows immediately after the extrusion moulding or finish forging operation, the particular workpiece would be lifted by one of the ejector pins 27, so far that the lower edge of the shank of the workpiece lies flush with the line separating the sliding table 26 from the fixed support 29.

The deforming machine described can in certain instances act as a spindle impact press for stamping purposes, the wedge improving the stability of the ram and reducing the stress on the spindle.

When the deforming machine is operated as a hydraulic press, the energy of the rotating flywheelspindle system is initially transformed into pressing work when the tool comes into contact with the workpiece. The pressing operation on the workpiece then continues hydraulically, the ram speed under load being infinitely adjustable, as possible in the case of hydraulic presses.

The percussion mechanism may comprise an electric motor. It is advantageous however for the percussion mechanism to consist of a hydraulic piston-cylinder system whereof the diameter is smaller than the diameter of the piston-cylinder system acting as a press mechanism. In this case, the percussion mechanism and the press mechanism are both driven by the same source of energy, namely fluid under pressure.

Filling water and water under pressure may be fed consecutively for pressing action to the hydraulic piston-cylinder system operating as a pressing mechanism. It is appropriate however for the hydraulic pistoncylinder system operating as a pressing mechanism to be connected to a source of water under pressure only, to which the piston-cylinder system operating as a striking or stamping mechanism is then advantageously also connected. Since, in point of fact, the stroke of a ram impelled through a wedge is smaller than that of a hammer, it is no longer necessary to operate with fllling water.

The short stroke of a wedge-driven ram may lead to difficulties if a long workpiece is produced by pressing, e.g. flow" pressing, because this long workpiece cannot be extracted below the ram from the mating tool which co-operates with the tool situated on the ram.

This is why the invention has specified that the mating tools co-operating with the tools situated on the ram are preferably to be arranged on a sliding table or platform. In this embodiment, workpieces can be fed to beneath the ram solely for deforming purposes, and can be withdrawn from beneath the ram by means of the sliding table, for handling operations.

In other words, the invention has specified a wedge" press which may be operated by means of possibly a spindle as well as of a hydraulic cylinder-piston driving mechanism. The spindle press described is particularly appropriate to comply with the specific requirements of modern processing technology. Numerous workpieces are thus produced in several operations, for which purpose each individual operation frequently requires a different pressing characteristic. For example, in the production of rear axle shafts (flange with contiguous shaft of greater or lesser length) and analogous parts, the initial operation consists of flow-pressing, the flange being forged subsequently in a second tool. A relatively small pressing force is required for a relatively long deforming stroke, in the case of flowpressing. The speed of deformation should moreover be approximately constant. This condition is best fulfilled by the hydraulic press having a direct cylinderpiston drive acting on a wedge and ram.

By contrast, in this example, there will be required a considerable forging force for a comparatively short distance of deformation during the second operation, for the forging of the flange. Moreover, the period of contact under pressure between the workpiece and tool should be as short as possible, because (in view of the considerable area of contact (flange) a considerable heat exchange, which heats the tool and thus promotes wear, would otherwise occur. In the present example, the second operation requires a pressing characteristic which corresponds to a spindle impact press.

The workpieces referred to in the example above could heretofore be produced economically only by using two separate machines. In view of the ease of comitantly affording a saving of space, the machine described can offer better prospects of automation and ease of control, a high speed being attainable with a possible fast workpiece throughout in eccentric presses, with little loss of heat by the workpiece and consequent high productivity and efficiency.

I claim:

1. A forming apparatus comprising means for selec tively pressing or impacting and including forcetransmitting means operatively connected to a reciprocatable ram including plural tool elements for effecting independent forming operations, the force-transmitting means comprising, in combination, a drive assembly operatively connected to a wedge member, the wedge member being operatively connected to a threaded spindle, said spindle having a longitudinal axis opera tively connected to and extending in the direction of converging wedge surfaces of the wedge member, transversely to the direction of reciprocation of the ram, said drive assembly including selectively displacable fluid pressure-operated portions for selectively operating the reciprocatable ram through said wedge member for effecting press forming operations, said portions including a second drive, said sprindle, when rotated by said second drive, being operative to move said wedge member and effect impact-forming operations.

2. The apparatus as claimed in claim 1 in which said fluid-pressure operated portions comprises hydraulically-operated variable-dimensioned effective piston portions, one piston portion being operatively connected to said wedge for effecting an impacting mode of operation to the ram and another of the piston portions being operatively connected to said wedge for effecting a pressing mode of operation to the ram.

3. The apparatus as claimed in claim 2 in which one of said piston portions is tubular and the other piston portion is axially aligned therewith.

4. The apparatus as claimed in claim 1 including a displacable support table operatively mounted beneath said plural tool elelements whereby introduction and removal of workpieces before and after having been formed is expedited during mass production of such work-pieces.

5. The apparatus as claimed in claim 1 in which said spindle comprises a threaded shaft operatively connected to said wedge.

Claims

1. A forming apparatus comprising means for selectively pressing or impacting and including force-transmitting means operatively connected to a reciprocatable ram including plural tool elements for effecting independent forming operations, the forcetransmitting means comprising, in combination, a drive assembly operatively connected to a wedge member, the wedge member being operatively connected to a threaded spindle, said spindle having a longitudinal axis operatively connected to and extending in the direction of converging wedge surfaces of the wedge member, transversely to the direction of reciprocation of the ram, said drive assembly including selectively displacable fluid pressureoperated portions for selectively operating the reciprocatable ram through said wedge member for effecting press forming operations, said portions including a second drive, said sprindle, when rotated by said second drive, being operative to move said wedge member and effect impact-forming operations.