US3507143A - Forming machine - Google Patents

Description

O. GEORG April 2-1, 1970 FORMING MACHINE Filed Dec. 4, 196? 2 Sheets-Sheet 1 Pm a mm @N Inventor:

o. GEORG 3,507,143 FORMING MACHINE April 21 1970 Filed Dec, 4. 19s? 2 Sheets-Sheet 2 Inventor:

United States Patent Int. or. 15513 11/00 US. Cl. 72-443 8 Claims ABSTRACT OF THE DISCLOSURE A forming machine selectably operable as a hammer or as a press which is provided with a pair of contrary reciprocally-movable tool members acting upon a workpiece in the known manner. In order to achieve the two operational states of the machine the effective resultant inertia of the tool members acting on the workpiece is variable. A simple Way of varying the inertia is disclosed in the form of an additional mass which can be operably connected to a threaded spindle engaging the tool members.

An alternative embodiment uses a pressure medium to drive the tool members by means of pistons and cylinders and to vary the inertia the pressure medium can be supplied in different quantities at different pressures from two separate hydraulic systems.

The present invention relates to forming machines which are selectably operable as a hammer or as a press.

The action of hammering differs from that of pressing primarily in that the former requires a substantially high working speed. In the case of hammering the re-shaping forces which are brought to act upon the workpiece are generated by sudden striking of masses upon one another and external forces do not appear. In the case of pressing, however, the pressure forces are conducted through the body of the press.

Attempts have been made to solve the problem of both hammering and pressing with the same machine in an economical manner.

Machines in the form of friction wheel spindle presses are known and the proposal was made of designing these for normal working with an impact speed exceeding 1 m./s. (on average with an impact speed of 2 m./s.) in order to be able to shape workpieces of medium or slight wall thickness. Thus the machine is operated with one specific impact speed and even though this is relatively high it was not possible to work the machine as a hammer or press according to choice. This was also not possible with a friction wheel spindle press which comprises two die-carrying tool members or sliders moved in opposite direction by the spindle and which strike one another with approximately equal work capacity. Equally well this applies to the so-called high-speed hammers since their construction does not render them suitable for pressing.

Hydraulically operated machines have been so arranged that the quantity of the pressure medium coming into effect is continuously regulable between zero and a particular quantity necessary to achieve the hammering speed with the specific pressure being substantially higher in pressing than in hammering.

Such hammer presses are in fact forging machines usable within wide limits, but they possess considerable disadvantages. In order that the impact of the ram can become effective, the frame or chassis of the machine must be at least ten times (typically twenty times) heavier than the ram, otherwise the' impact passes into the foundation so that the whole of the surroundings are shaken. Even if the frame is made sufficiently heavy, very high expense is necessary for the foundation in order to be able to achieve acceptance of the working of such machines.

It is an object of the present invention to provide a machine operable as a hammer or a press with a fraction of the frame weight hitherto necessary which transmits practically no vibration to the foundation.

A machine made in accordance with this invention utilizes the counter-impact principle.

According to the present invention there is provided a forming machine selectably operable as a hammer or as a press comprising (a) A frame,

(b) A pair of tool members,

(0) Guide means for guiding the tool members for movement relative to the frame,

((1) means for reciprocally driving the tool members in a contrary manner into operative relationship with a workpiece,

(e) Means for varying the resultant inertia of the tool members in their operative relationship whereby to control the functional operation of the machine as either a hammer or a press.

The words tool members as used throughout the specification and claims is intended to include tool carriers on which dies are mounted as well as the actual tools themselves. The invention is based upon the widespread knowledge that machanically satisfactory solutions are reached if in machines operable either as a hammer or as a press and working by counter-impact have movable masses, which determine the working capacity of the machine, whose inertia can be made variable.

According to a further feature of the invention this can be achieved in the simplest way by connecting and disconnecting additional masses. For this purpose machines are suitable which work with rotating working parts, for example with threaded spindles, so that by means of these the rotating movement can be converted into the reciprocating movement of the tool members. One possible embodiment of the invention is characterised, in that one or more motor-driven threaded spindles act upon contrarily moving tool members in the form of plungers or slides with differently directed thread pitches which are connectible with, and separable from, inertia masses by means of clutches. A preferred arrangement is to have the threaded spindle, the inertia mass and clutch concentric. Further advantages are obtained if the clutch is formed as a disc clutch and is electro-magnetically controlled. The clutch can, however, also be formed as an overload-slip clutch.

With a single-spindle arrangement, a satisfactory solution is reached if the thread of one section of the spindle engages the thread of a plunger slide nut and the thread of another section, of oppositely-directed pitch to the first, engages the thread of a frame slide nut. This solution leads to the possibility of mechanically coupling a standard, pole-changeable reversing motor directly with the threaded spindle, whereby the drive assumes a construc tion which requires no separate expense. The fact that the plunger slide is of a lower weight than the frame slide is compensated due to the fact that the plunger slide is moved with greater speed than the frame slide, so that the moving masses of the machine can be brought into action upon the workpiece with substantially conforming work capacity. It is therefore merely necessary for the threaded section of the spindle which engages the thread of the plunger slide nut to be equipped with a thread of greater pitch than the threaded section which engages the thread of the frame slide nut.

In the case of a machine with a multi-spindle arrangement the possibility exists of bringing threaded sections of-the same spindle into engagement with threads of nuts of substantially similarly formed but contrarily moving, plunger slides. This leads to the further possibility of connecting each of the plunger slides with a piston and permitting the pistons to work in separate cylinders, the working chambers of which are in connection through a conduit. If this conduit and the working chambers of the said cylinders are filled with pressure medium the pressure medium can be compressed by means of the pistons during the contrarily directed return stroke of the plunger slides, so that the working stroke takes place under the influence of the further compressed pressure medium, in which case it is'only necessary to satisfy the condition of keeping the thread pitch of the threadedspindles below the value at which self-locking would occur. The further possibility exists of connecting each of the plunger slides with a further piston and arranging these pistons in common cylinders the working chambers of which are connected with a pressure medium source. If these working chambers are'brought under the pressure of the pressure medium delivered by the pressure medium source, then as the distance between the two pistons increases, the plunger slides move apart to effect their return stroke but at the same time deliver the energy which is necessary to compress the pressure medium in the first-mentioned working chambers.

According to a further constructional embodiment of the present invention the plungers of the machine are piston-operated and the pistons are subjected to the influence of high-pressure and low-pressure hydraulic systems which have, apart from devices to produce different pressures and circulation quantities of the pressure medium, a reversing device and an on-and-off control.

constructional embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings wherein:

- FIGURE 1 is a diagrammatic longitudinal section of a forming machine made in accordance with the invention and having a single spindle drive;

FIGURE 2 is a diagrammatic longitudinal section of a re-shaping machine made in accordance with the invention and having a multi-spindle arrangement; and

FIGURE 3 is a diagrammatic longitudinal section of a further embodiment of a machine made in accordance With the invention.

As shown in FIGURE 1 the machine has tool members in the form of a frame slide 2 and a plunger Slide 3 normally carrying dies, which are guided in a body or frame 1 of the machine. A threaded drive spindle 4 has two threaded portions thereof which differ from one another in. direction of pitch and the pitch itself. The spindle 4 is carried near is upper end in a collar bearing 5 and at its centre in a pivot bearing 6. The spindle 4 engages with threads of opposite nature and diiferent pitch provided in threaded nuts 7 and 8 belonging to the frame and plunger slides 2, 3 respectively. The plunger slide 3 has a Weight somewhat lower than that of the frame slide 2 but the pitch of the thread of the spindle 4 which engages with the thread of the plunger slide nut 8 is greater than the pitch of the thread of the spindle 4 which engages with the thread of the frame slide nut 7. Therefore, the plunger and frame slides 23 voperate with equal work capacity upon the dies (not shown), normally situated between the plunger and frame slides, and thereby upon the workpiece. Drive means in the form of a selectable speed reversable motor 9 is mounted at the upper end of the machine and drivably connected to the spindle 4. The speed of the motor 9 is such that it can change by a ratio of approximately 1:4, so that, for example, in pressing the impact speed of the slides 2, 3 can be set to 1 m./s., while in hammering a higher impact speed of 3 m./s. is used. If approximately the same energy is to be brought into action in both types of machine operation, which is not a prerequisite but is usual, then accordingly the inertia masses, or more particularly the inertia moments must be in'the ratio of 1:16. Forthis reason the provision of a selectable additional mass is desirable. This can be effected in the simplest way by the provision of an inertia mass in the form of an annular member 10 connected to a hub 11 which is carried by the spindle 4. To enable the member 10 to be operable as and when required an electro-magnetically controlled disc clutch 12 is situated between the member 10 and hubs 11. A magnet 13 for controlling the clutch 12 is provided within a housing 14 containing the member '10 and the winding (not shown) for the magnet 13 is also located in the housing 14.

The manner of operation of the machine is as follows:

Let it be assumed that when the spindle 4 rotates in the clockwise direction in plan view relativeto the electric motor 9, the frame slide 2 and plunger slide 3 move towards one another and impact to deform the Workpiece. To reset the slides 2, 3 the rotation of the spindle 4 is reversed by reversing the direction of the motor 9. If, prior to the clockwise rotation of the spindle 4, the clutch 12 is engaged and a lower rotation speed of the motor 9 selected, then when the slides 2,3 are moved the masses of the slides 2, 3 have a high inertial movement as a result of the engagement of the member 10. This working action of a combination of high mass and low rotation speed of the spindle 4 is suitable or pressing and thus for example for pre-shaping, the slides 2, 3 accelerating fairly slowly as the spindle 4 and slides 2, 3 are free from the higher breakage forces. The clutch 12 also reliably prevents overloading.

The requisite conditions are different in final forging, where a high final pressure in a hammer action is necessary which the spindle 4 and slides 2, 3 could not supply if the above-mentioned conditions were to prevail. In order to achieve these new conditions the clutch 12 is dis: engaged and the motor 9 is operated with a higher rotation speed. Thus, the two slides 2, 3 are accelerated to hammering speed so that on the impact the requisite high forging forces occur. The forces in the slides 2, 3 and in the spindle 4 occur are in the order of magnitude which corresponds to a low inertia moment of the spindle 4 and its hub 11 in their co-operation in the re-shaping. It is therefore possible in the hammering operation of the machine to generate re-shaping forces which far exceed the static capacity of the spindle and frame slide crosssections.

As shown in FIGURE 2 a forming machine has a multi-spindle arrangement consisting of the threaded spindles 1S and 16 each of which is similar to the spindle 4 shown in FIGURE 1 and carried in a hearing at a lower part of the frame of the machine. Two tool members in the form of plunger sides 17, 18, engage threaded nuts designated by 19, 20, 21 and 22 and as shown, the spindle 16 engages the nuts 19 and 21 and the spindle 15 engagesthe nuts 20 and 22. The spindle 16 has in the region in which it is in engagement with the plunger nut 19 a pitch which is opposite in direction to that of the corresponding region of the threaded spindle 15 which it is in engagement with. the plunger nut 20. The same applies to the threaded sections of the spindles 15, 16 in engagement with the corresponding nuts 21, 22 of the plunger slide 18. The upper and lower threadedsections of each spindle 15, 16 in engagement with the hub 19, 21 and 20, 22 respectively have opposite direction'pitches.

A direct drive to the plunger slides 17, 18, is not provided in this embodiment but for driving means there is used a pressure medium which can adapt itself automatically to the resistance of the masses to be accelerated. Gases such as highly compressed air or better still nitrogen are suitable for the pressure medium. The pressure of the cylinders 23, 24 to form pistons therefor. In this way the pressure medium is confined in a closed system and acts like a spring under stress. It is only necessary to compensate for losses due to leakages.

The plunger slides 17, 18 are equipped with further pistons 26, 28, 30 and 31. The pistons 26, 28 move in a common cylinder 26 and the pistons 28, 30 and 31 move in a common cylinder 27. The working chambers of the cylinders 26, 27 are each situated between the pistons 26, 28 and 30, 31 and connectible to a hydraulic pressure medium source. If a pressure medium is passed into the working chambers the pistons 26, 28 are driven apart and the pistons 27, 30 are driven apart, so that the plunger slides 17, 18 carry out their return stroke and compress the pressure medium in the working chambers of the cylinders 23, 24.

In order to be able to vary the effective inserts of the plungers 17, 18 similar devices are provided to those in the embodiment according to FIGURE 1. In particular, inertial masses in theform of annular members 32, 33 are connectible with spindle hubs 36, 37 through disc clutches 34, 35. The disc clutches 34, 35 are controlled by means of pistons 38, 39 contained in cylinders 40, 41. The disc clutches 34, 35 can 'be brought into an operating position by passing a pressure medium into the working chamber of the cylinders 40, 41.

The manner of operation of this machine corresponds to that previously described with reference to the machine of FIGURE 1.

Initially, the pistons 28, 29, 30 and 31 hold the plunger slides 17, 18 in an outer deadpoint position against the action or resilience of the pressure medium in the cylinders 23, 24. If the machine is to be set in operation to carry out a working stroke pressure medium is removed from the working chambers of cylinders 26, 27, and the pressure exerted by the compressed medium in the working chambers of cylinders 23, 24 can act upon the end faces of the piston rods therein and hence on the plunger slides 17, 18. The plunger slides 17, 18 therefore move towards one another and the spindles 15, 16 rotate. Assuming the members 32, 33 are connected to the hubs 36, 37 the acceleration of the plunger slides 17, 18 towards one another is relatively low. The hydraulic pistons 26, 28 and 27, 30 return the plunger slides 17, 18 into the initial position after a working stroke.

The situation is different when the clutches 34, 35 are in the disengaged position, where the acceleration of the slides 17, 18 is substantially higher.

Once again in the former case the re-shaping machine carries out the action of a press, in the latter case that of a hammer.

The compressed medium situated in the cylinder chamber 23, 24 and in the conduit 25 automatically adapts itself to both possibilities. The clutches 34, 35 are also active as slipping clutches to ensure that a maximum pressure is not exceeded in pressing. In the case of hammering they are disconnected and the pressure forces can be as high as desired without the spindles 15, 16 being overloaded.

Both embodiments disclose a machine which can be constructed with the minimum of expenditure but providing the maximum utilization of energy. The balancing of masses is practically ideal, both in relation in terms of linear displacement and rotation. All the occurring forces and moments remain within the re-shaping machine and are not transmitted to the machine foundation, so that the machine does not need to be set up in special places because even in hammering work it works without undue vibration.

The machine shown in FIGURE 3 has a frame or chassis 42 in which there are guided two tool members in the form of rams 43, 44. Pistons 45, 46 are guided in cylinders 47, 48 and the pistons 45, 46 are attached to the rams 43, 44 respectively. Pressure medium can act on either side of the pistons 45, 46. The upper part of the cylinder 47 is in communication with the lower part of the cylinder 48 through a conduit 49 in a similar manner the lower part of cylinder 47 is in communication with the upper part of cylinder 48 through a conduit 50. The lower piston 44 has a somewhat larger diameter that the piston 45 in order to compensate for the influence of the weight of the upper ram 43. The control of the pistons 45, 46 and thus the driving of the ram 43, 44 is achieved by means of a control piston 51 which is movable in a cylinder to cover the inflow and outflow passages of the cylinders 47, 48 and is operated, for example, by means of a control lever 52. On lowering of the lever 52 pressure medium is applied to move the pistons 45, 46, and thereby, the rams 43, 44 towards one another. Conversely on raising the lever 52 the pressure medium moves the pistons 45, 46, and thereby the rams 43, 44, away from one another.

So that the machine may be operated on the one hand as press and on the other as hammer it is necessary to provide a system for changing the inertia of the masses. In this embodiment this is effected by using a-small quantity of pressure medium per unit of time at high specific pressure when operating as a press and a large quantity of pressure medium in the same unit of time at low specific pressure when operating as a hammer. In general, for pressing operations the pressure medium needs to be at a pressure of several hundred atmospheres whereas for hammering operations a pressure of ten atmospheres at the most is necessary. Since the differences required are considerable it is advantageous to use high and low pressure systems as 'will now be described.

The low pressure system utilizes pressure medium in the form of gas and has a pump 53 which is driven by a motor 54, a storage container 55, a regulating valve 56 and a reservoir 57, a pressure indicator 63 and also the necessary conduits having a larger cross-section than those of the high pressure system. The high pressure system also utilizes pressure medium in the form of gas and has a high pressure pump 58 with a drive motor 59, a storage container 60, a regulating valve 61 a reservoir 62 a pressureindicator 64 and conduits of smaller cross-section than those of the low pressure system. The regulating valves 56 and 61 have the task of connecting the pressure conduits of the pumps 53, 58 with the storage containers 55 and 60 when a maximum pressure indi cated by the pressure indicators 63 and 64 occurs.

To switch over the machine from hammering to pressing work and vice versa a control valve 65 having a stem with four collars. A main high pressure supply conduit 66 and a main low pressure supply conduit 67 open communicate with an upper section of the valve 65 and outlet conduits 68 and 69 are connected to a lower section of the valve 65. The valve 65 has a control piston 70 connected to a manually operated lever 71. If the hand lever 71 is moved upwards the piston 70 opens the high pressure supply conduit '66 and the pertinent discharge conduit 68, so that by means of the lever 52 the machine can be operated as a press. If the lever 71 is moved downwards the piston 70 opens the low pressure conduit 67 and the pertinent discharge conduit 69 so that by means of the lever 52 the machine can be operated as a hammer. The low pressure part of the hydraulic system of the machine can also be used to fill the cylinders with the press idling, and subsequently to switch over to high pressure.

Generally speaking, in this embodiment only one of the pistons can be driven directly and in this case the counter-ram is operated in known manner positively by means of a mechanical, pneumatic, hydraulic or electric coupling. In pressing it is also possible to disconnect one side of the machine completely and work with only one piston, since in pressing there is no fear of the occurrence of jarring.

I claim:

1. A forming machine selectably operable as a hammer or as a press comprising (a) a frame,

(b) a pair of tool members,

() guide means for guiding the tool members for movement relative to the frame,

((1) means for reciprocally driving the tool members in a contrary manner into operative relationship with a workpiece,

(e) means for varying the resultant inertia of the tool members in their operative relationship whereby to control the functional operation of the machine as either a hammer or a press.

2. A machine according to claim 1, wherein the means for driving the tool members comprises a threaded spindle engaging the tool members and a prime mover for rotating the spindle.

3. A machine according to claim 2, wherein the means for varying the resultant inertia comprises an inertia mass operably connectible to said spindle and means for altering the speed of said prime mover.

4. A machine according to claim 1, wherein the means for driving the tool members comprises hydraulic piston and cylinders and the means for varying the resultant inertia includes threaded spindles engaging the tool memhers and an inertia mass operably connectible to each of said spindles.

5. A machine as claimed in claim 4, wherein a piston rod is connected to each tool member and there is provided a cylinder into which each piston rod extends, the

cylinders being in closed communication with one another and containing a pressure medium.

6. A machine according to claim 1, wherein two threaded spindles engage each tool member and the means for varying the resultant inertia comprises inertia masses and clutches each operable to selectively connect the associated inertia mass to one of the spindles.

7. A machine as claimed in claim 2, wherein the means for varying the resultant inertia comprises an inertia mass 10 operably connectible to said spindle by means of a clutch.

8. A machine as claimed in claim 1, wherein the means for driving the tool members comprises hydraulic piston and cylinders and the means for varying the resultant inertia comprises a high and a low pressure hydraulic system selectably operable to supply pressure medium at diiferent quantity and pressure to the piston and cylinders.

References Cited UNITED STATES PATENTS 1,913,663 6/1933 Ferris 72 154 2,863,343 12/1958 Steinfort 72-453 3,031,903 5/1962 13111611 72-443 3,035,514 5/1962 Harvanek 100 289 3,173,286 3/1965 Dischler 72-4 53 3,376,728 4/1968 Nemessanyi 72 454 3,422,658 1/1969 Michelson 100269 RICHARD J. HERBST, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R.

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