US3055513A - Workpiece supporting device - Google Patents

Description

B. KRALOWETZ WORKPIEQCE SUPPORTING DEVICE ksept. 25, 1962 `Filed March 14, 1961 3 Sheets-Sheet 1 F/GJ Sept. 25, 1962 Filed March 14, 1961 B. KRALOWETZ WORKPIECE SUPPORTING DEVICE 5 'Sheets-Sheet 2 11:01 vENra&

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WORKPIECE SUPPORTING DEVICE Filed March 14, 1961 3 Sheets-Sheet 3 United States Patent Oiitiee 3,055,513 Patented Sept. 25, 1962 3,055,513 WORKPIECE SUPPORTING DEVICE Bruno Kralowetz, St. Ulrich, near Steyr, Austria Filed Mar. 14, 1961, Ser. No. 95,583 Claims priority, application Austria Mar. 17, 1960 8 Claims. (Cl. 214-1) In forging machines in which the workpiece is moved horizontally between the hammers, the gripping head which holds and feeds the workpiece may not be able to ensure an exactly central position of long workpieces so that an additional workpiece support is required close to the forging box. Since it is necessary to work workpieces having different initial cross-sections and different workpieces are obtained after forging, the workpiece support must ensure the correct position of the workpiece independently of the diameter of the workpiece without requiring a complicated adjustment of the support. Au automatic adaptation of the support to changing diameters and other dimensions of the workpiece is desired. It is an object of the invention to solve this problem.

The invention resides essentially in that two pivoted levers which grip the workpiece like tongs are mounted on the forging box or the like, one of which levers consists of an actual supporting lever and is adjustable with the aid of a hydraulic piston drive Whereas the other consists of a -sensing lever which responds to the radial dimension of the workpiece and acts on a control valve or the like of the piston drive to cause the supporting lever to be automatically pivotally moved to a position in which the axis of the supported workpiece is in the desired position. The radial dimension of the workpiece deter-v mines the amount of the pivotal movement of the sensing lever and this pivotal movement is utilized for the control of the hydraulic piston drive to move the supporting lever to the correct position below the workpiece.

A particularly suitable design will be obtained if the supporting lever is a rigid double-armed lever and the sensing lever consists of two arms which extend away from each other and are coupled by a reversing gear for pivotal movement in mutually opposite directions, the piston drive acting on that arm of the supporting lever which extends away from the workpiece and a spring being provided which tends to pull together this arm and that arm of the sensing lever which is disposed on the same side and acts on the control valve or the like, the housing of the control valve or the like being connected to the movable part of the piston drive. Since the arms of the supported and sensing levers directed away from the workpiece are held together by a spring and that arm of the sensing lever which is directed toward the workpiece will perform a pivotal movement in a direction opposite to the direction of movement of the other arm of the sensing lever, the tongs formed by the supporting and sensing levers will be opened or closed if appropriate hydraulic pressure is applied to the piston drive whereas an additional drive of the sensing lever is not required. If the tongs are closed and a workpiece is introduced, this will rst urge thesensing lever away from the supporting lever so that the sensing lever arm directed away from the workpiece is also pivotally moved against the force of the spring pulling this arm toward the supporting lever arm. This pivotal movement moves the control valve or the like so that the application of pressure to the piston drive is changed and this drive moves the supporting lever into the position which corresponds to the workpiece diameter sensed by the sensing lever.

To enable the provision of a common pivotal axis for the supporting and sensing levers, the reversing gear is designed as an epicyclic gear, the two sun wheels of which are rigidly connected each to one arm of the sensing lever whereas the planet wheels are prevented from revolving about the axis of the sun wheel or the common pivotal axis of the pivoted levers. To enable the control valve to follow the pivotal movement of the sensing lever arm relative to the supporting lever, a spring is provided which acts on the control valve and urges a feeler pin outwardly against the associated arm of the sensing lever and which has a smaller force than the spring which pulls the sensing lever arm toward the supporting lever arm.

The hydraulic system for the supporting device is characterized according to the invention in that the piston consists of a stationary cylinder and a slidable piston which is connected by its piston rod to the valve housing and the supporting lever and which has pressure iiuid permanently applied to its rod side to act on the levers in the closing sense whereas a conduit opening into the cylinder on the cover side can be connected by a magnetic valve also to the pressure supply conduit or to a connecting conduit leading to the control valve, which either connects to a drain or closes the connecting conduit, the control valve spring tending to urge this control valve to this closing position. When the cover side of the cylinder is connected to the drain by the magnetic valve and the control valve, the tongs formed by the two levers close. When the cover side is connected to the pressure supply conduit, the two levers open because the effective piston area on the cover side is obviously larger than on the rod side so that the piston is moved in the opening sense. Since the control valve opens to the drain or throttles this connection until the connection conduit has been entirely closed, any piston position and any desired angular position of the Supporting lever can be adjusted by the respective position of the control valve.

The invention will be explained more fully with reference to the accompanying drawing, in which FIG. l is an elevation showing the entire device, partly in section,

FIG. 2 is an enlarged axial sectional view showing the control valve,

FIG. 3 is an enlarged sectional view taken on line Ill-III of FIG. 1 and shows the reversing gear for the sensing lever and FIG. 4 shows diagrammatically the hydraulic system of the device.

FIG. 5 is a longitudinal sectional view showing as a detail the jaws for engaging the workpiece in closed position.

The forging box 1 is arranged to have the workpiece moved therethrough in a horizontal direction. Such an arrangement of a forging box being apparent from the U.S. Patent No. 2,562,643, a further disclosure of this arrangement is not considered necessary.

The forging box 1 or the like has flanged thereto a pivot pin 2, on which a rigid double-armed supporting lever 3 is pivotally movable. The pivot pin 2 further mounts a sensing lever which consists of the two arms 4 and 5, which are coupled for pivotal movement in mutually opposite senses by areversing gear. During an upward movement of the arm 4 in the clockwise sense, the arm 5 will be pivotally moved upwardly in the counterclockwise sense. A movement of the arm 5 in the clockwise sense will cause the arm 4 to be pivotally moved downwardly in the counterclockwise sense.

According to FIG. 3 the reversing gear consists of an epicyclic gear, which comprises a sun wheel 6 connected to the lever arm 4, a second sun wheel 7 connected to the other arm 5, and two planet wheels 8 held against revolving about the axis of the pin 2 since the common bearing pin 9 of these planet wheels is xed in the pin 2. The arm 5 of the sensing lever is coupled to the arm of the supporting lever 3 on the same side by a spring 10,

which tends to pull these two arms together. The other arm of the supporting lever 3 and the sensing lever arm 4 are provided with replaceable jaws 11, which are tapered in the direction at right angles to the plane of the drawing to form a wedge-shaped gap in the closed position so that the jaws will be forced apart by a workpiece being inserted.

For the adjustment of the supporting lever 3, a hydraulic piston drive is provided, which consists of a stationary cylinder 12 and a displaceable piston 13. The piston rod 14 is connected by a buffer spring 15 to the housing 16 of a control valve 17. That arm of the supporting lever 3 which is remote from the workpiece is connected by means of a slide block and cam slot to the valve housing or an outer sleeve surrounding the same. Thus, a downward movement of the piston 13 will cause a pivotal movement of the supporting lever 3 in the clockwise sense and, as the sensing lever arm is coupled by the spring to the supporting lever arm on the same side, also a downward pivotal movement of the sensing lever arm 4 in the counterclockwise sense so that the tongs formed by the levers are closed. The upward movement of the piston will cause the tongs to be opened (position shown in FIG. 1). The control valve 17 is urged upwardly by a spring 18, which is weaker than the spring 10. A slidable feeler pin 17l is urged against the arm 5 of the sensing lever.

Pressure oil is permanently applied to the piston 13 through the conduit 19, 20. The conduit 21 from the cover side of the cylinder 12 leads to a magnetic valve 22. When the magnetic valve 22 is in the position shown in FIG. 4, the conduit 21 is also connected to the pressure supply conduit 19. As a result, pressure is applied to the cover and rod sides of the piston 13, which will move upwardly because the effective piston area is larger on the cover side than on the rod side. A connecting conduit 24 leads from the magnetic valve 22 to the control valve 17, to which a drain conduit 2S is connected. 26 is a valve for maintaining a constant pressure; this valve ensures that the pressure in the cylinder 12 on the rod side will not drop below a pre-set value.

As has already been mentioned, the illustrated position of the magnetic valve 22 corresponds to an opening movement of the two levers 3 and 4, 5 because the piston 13 is urged upwardly as it has a larger area on its underside so that the supporting lever 3 is compelled to perform a counterclockwise pivotal movement. To provide a support for the workpiece, the magnetic valve 22 is displaced to the right. In this position the conduit 21 is connected to the connecting conduit 24. The spring 10 being stronger than the spring 18, the control valve is forced down by the sensing lever arm 5 and the feeler 17 so that the conduit 24 is connected to the drain 25. As a result, the oil from the cover side can liow off through 21, 22, 24 and 25 and the piston 13 descends owing to the permanent application of pressure oil through conduits 19 and 20 to the rod side; the tongs formed by the levers 3 and 4, 5 are then closed. The insertion of a workpiece between the jaws 11 will then result in an upward pivotal movement of the sensing lever arm 4 and, by means of the reversing gears 6, 7, 8, in an upward pivotal movement of the arm 5 against the force of the spring 10. During the upward pivotal movement of the arm 5 the control valve can rise under the action of the spring 1S to throttle and finally close the conduit 24. The supply of pressure oil through the supply conduit 23 and the valve 26 into the conduit 24 and through the valve 22 and the conduit 21 being continued, the pressure on the cover side of theA cylinder 12 builds up, the piston 13 rises and the supporting lever 3 is pivotally moved in the counterclockwise sense. The upward movement of the piston and of the housing 16 and the supporting lever 3 causes also an approach of the right-hand arm of the supporting lever 3 to the sensing lever arm 5 and the spring 10 becomes again effective so that the control valve 17 is forced down against the force of the spring 18 whereby the passage to the conduit 25 is opened sufiiciently to balance the forces acting on the piston 12. When the equilibrium of forces has been established, the supporting lever 3 is also in an angular position in which the axis of the workpiece to be supported is exactly in the desired position indicated by the cross-lines in FIG. 1.

I claim:

1. A device for supporting a workpiece while it is fed in the direction of its axis, said device comprising a rigid support, first and second lever means pivoted to said support, each of said first and second lever means having a first arm and a second arm, said first arm of said first lever means being adapted to engage and support said workpiece, said first arm of said second lever means being arranged to engage said workpiece `at a point spaced in a direction transverse to said axis from the point of said workpiece engaged by said first lever means whereby said second lever means senses a cross-sectional dimension of said workpiece, said second arms extending away from said work-piece, said first and second arms of said first lever means being rigidly connected to each other and said first and second arms of said second lever means being pivotally movable relative to each other, said device further comprising a reversing gear coupling said arms of said second lever means for pivotal movement in mutually opposite directions, first biasing means urging said second arms toward each other, a hydraulic piston drive having a movable part, a hydraulic system, which is connected to said piston drive and incorporates a control valve comprising two relatively movable valve parts, which are movable into and out of a predetermined neutral position, one of said valve parts being operatively connected to said movable part of said piston drive for movement in unison therewith, said hydraulic system being adapted to operate said piston drive to move said one valve part relative to the other valve part, said valve being adapted to interrupt the operation of said piston drive by said hydraulic system when said valve parts are in said neutral position, said second arm of said first lever means being operatively connected to said movable part of said piston drive and to said one valve part for movement in unison therewith, said device further comprising second biasing means weaker than said first biasing means and urging said other valve part into engagement with said second arm of said second lever means so that said other valve part is operatively connected to said second arm of said second lever means for movement in unison therewith, whereby any pivotal movement of said first arm of said second lever means in one direction by a predetermined amount will move said valve parts out of said neutral position relative to each other and the ensuing operation of said piston drive will cause a movement of said first arm of said first lever means and, under the action of said first biasing means and reversing gear, of the first arm of said second lever means, in the opposite direction by half said amount, and the resulting movements of the second arms of said first and second lever means will cause said valve parts to be restored to said neutral position relative to each other so that said first arm of said first lever means is arranged to support said workpiece with its axis in a predetermined position regardless of the magnitude of said cross-sectional dimens1on.

2. A device as set forth in claim 1, in which said first biasing means comprise a spring connected to said second arms of said first and second lever means.

3. A device as set forth in claim 1, in which said one valve part comprises a halve housing and said other valve part comprises a feeler and said second biasing means comprises a spring interposed between said housing and said feeler.

4. A device as set forth in claim 1, in which said support comprises a forging box of a forging machine.

5. A device as set forth in claim 1, in which said forging box is arranged to have said workpiece passed therethrough in a horizontal direction.

6. A device as set forth in claim 1, in which said reversing gear comprises an epicyclic gear which comprises two coaxial sun wheels each of which is rigidly connected to one arm of said second lever, and planet Wheels in mesh with said sun wheels and held against revolving about the axis of said sun wheels.

7. A device as set forth in claim 1, in which said piston drive comprises a stationary cylinder and a piston slidable in said cylinder and forming said movable part and having a piston rod connected to said second arm of said 4irst lever means and to said one valve part, said hydraulic system comprising a pressure conduit permanently connected to said cylinder on the rod side of said piston to urge said rst arms of said rst and second lever means toward each other, a drain, Aan arbitrarily operable valve, a irst conduit connecting said arbitrarily operable valve to said cylinder on Ithe `side opposite to said rod, a second conduit connecting said arbitrarily operable valve to said pressure conduit, a third conduit connecting said arbitrarily operable valve to said control Valve, said arbitrarily operable valve being movable between two positions in which it connects said rst conduit to said second and third conduits, respectively, said control valve being arranged to close said drain to such an extent as to establish an equilibrium of forces acting on said piston when s-aid valve parts are -in said neutral position relative to each other, said valve parts being movable to two additional positions relative to each other, said control Valve being arranged to substantially open said drain in one of said additional positions and to close said third conduit in the other of said additional positions, said second biasing means being arranged to urge said other valve part toward said other additional position relative to said one valve part.

8. A device as set forth in claim 7, in which said arbitrarily operable v-alve is a magnetic valve.

References Cited in the tile of this patent UNITED STATES PATENTS 587,909 Anderson Aug. l0, 1897 2,240,688 Conner Jan. 23, 1937 2,470,983 Hendricks May 24, 1949 2,692,059 Bolling Oct. `19, 1954 2,718,321 Westermeyer Sept. 20, 1955 2,732,083 Smith Jan. 24, 1956

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