US2920729A - Clutches for machine drives - Google Patents

Description

Filed April 21, 1955 INVENTOR ALFRED BREUER ATTORNEYS CLUTCHES FOR MACHINE DRIVES Alfred Breuer, Dusseldorf, Germany, assignor to Schloemann Aktiengesellschaft, Dusseldorf, Germany Application April 21, 1955, Serial No. 502,910 In Germany November 21, 1949 Public Law 619, August 23, 1954 Patent expires November 21, 1969 3 Claims. (Cl. 192-18) Shears of the type in which the knife portions rotate and engage material to be rolled passing through between the shafts and cut same are known. Such shears are generally driven in such a manner that the knives or their supports are made to rotate out of their position of rest at each operation, so as to cut the material into the desired lengths.

The invention relates to a shears of this kind in which a continuous drive motor is used, said shears being regulated by means of an electromagnetic clutch wherein a disc mounted displaceably on the driving shaft is brought alternately by electromagnetic means into friction connection with a friction disc mounted on the driving shaft and with a fixed brake disc. The braking, if the cutting operation is to take place properly, must be effected in such a manner that the knives are brought exactly back into their initial position. Should this not take place, troublesome differences could arise between the speeds of the knives and of the material.

According to the invention the knives are returned to their exact original position by means of a rotatably mounted electromagnetically actuated brake and clutch means. The electromagnetic brake disc, after the knives have passed beyond their initial position, is driven in the opposite direction and returns them to their initial position. The exactness of this position provides no difiiculty if there is a large transmission ratio between its drive motor and the brake disc.

These working cycles are controlled electrically and the motor which returns the knives is switched oif automatically immediately the knives return to their initial position.

The new shears are illustrated diagrammatically in the accompanying drawing. i A

The shears include the knives 3 and 4 carried by crank-shaped carriers 1 and 2 respectively. The carriers are mounted on shafts 5 and 6 operatively coupled by the respective worm wheels 7 and 8 with a worm gear portion 9 on the main shaft 9a that is adapted to be actuated by the main drive motor 10. A clutching arrangement is interposed between the end of the shaft 9a and the motor 10, and includes two annular electromagnetically actuated housing components 11 and 12 on opposite sides of a disc 13. The disc 13 is slidably keyed to the end of the worm shaft 9a and is axially movable between positions wherein it is electromagnetically clutched against either the face of the housing of the component 12 o'r 11 respectively. When the electromagnetic means 11 is energized the disc 13 is pulled to the left to the position shown in the drawing and applied against the end face of the housing of this electromagnetic means for exerting a braking action. When the electromagnetic circuit to the component 12 is energized, with the circuit to component 11 de-energized, the disc'l3 is moved to the right against the housing of electromagnetic means 12, so that the motor 10 again drives the worm shaft 9a. Since the annular electromagnetic means 11, also of disc form,

nited States Patent 0 "ice is rotatably mounted on the end of shaft 9a, it will turn freely on this shaft. This electromagnetic disc 11 is in the form of a worm wheel having teeth 15 thereon in engagement with a worm gear 16 driven by motor 17.

Assuming in the drawing that neither electromagnetic means 11 or 12 is activated, then both motors 10 and 17 may run continuously, motor 10 in a direction to drive shears 3, 4 forward through the direction connection of clutch components 12, 13 if electromagnetic means 12 is energized and motor 17 in a direction, with worm and 1 wheel reduction gear 15, 16, to drive shears 3, 4 backward at a very reduced speed through clutch 11, 13 if electromagnetic means 11 is activated.

In operation, assuming the device to be at rest the shears 3 and 4 in their original position as seen in the drawing, means in common use in devices using such instead of merely placing stops in their paths which would need later to be removed, the electromagnetic clutch 12,

13 remains engaged till the knives 3, 4 pass their original position, then electromagnetic means 12 is de-energized and electromagnetic means 11 is energized so that the shears are slowly turned back by motor 17 operating through worm and wheel 16, 15. One way to stop the backward turning shears at their correct location is seen at 18 which is a stop interposed behind the shear crank 2 after it has passed. When the crank 2 strikes the stop I the clutch 11, 13 will slip and hold the shears in ready" position for the next cycle of operation. Otherwise, the motor 17 may be stopped when the shears near their original position by any known switch interposed in the motor circuit. The gear ratio of the worm and wheel 1 16, 15 will effectively stop the shears in their proper position and with clutch 11, 13 still engaged will hold them in place waiting for the next cycle of operation.

The working of the device according to the invention is such that as soon as the knives have passed beyond their initial position and are braked by the disc 13 which is forced against the electromagnetic disc 11, they are rotated back again into the initial position by means of the motor 17 which starts automatically. Although the motor can easily be halted by'means of its controls as soon as the knives have'reached their original position,-

a stop 18 can also be provided and controlled soas to enter and leave the effective position and act as a stop for the knives. The friction coupling between 11 and 13 lets the motor continue to run.

A simple system of electric controls is shown in the drawing but it will be appreciated that many other electrical systems may be devised and the circuit shown is purely diagrammatic as the specific system of electric controls is not a part of the present invention.

A power distribution and switch panel is shown at 20 and wires or leads 10a and 10b feed continuously operating motor 10, while wires 17 and 17b feed motor 17.

-An appropriate switch, not shown, for each of these 0 actuated by current running in the wires to switch 12d to close the circuit 12a, 12b to operate electromagnetic means 12. Simultaneously, solenoid 22, that is in parallel with solenoid 21 over wires 23 and 24, is activated to open switch 110 and thus break the circuit 11a, 11bto place electromagnetic means 11 out of operation.

Pin 8a will then move with worm wheel 8 until it again strikes lever 12d" and moves it to the left: Thus, as pin 8a passes switch 12d, opens switch 12d, which opens circuit 12a, 12b" and simultaneously deenergises solenoids 21 and 22 so switch 12c o'pens under the influence of spring 120 and switch 11c closes under the influence of spring 11a. The closing of switch 1110 energises the electromagnetic clutch means 11 so the disc 13 engages electromagnetic means 11 to drive worm shaft 9' slowly in the reverse direction.

When the pin 8 strips switch 12d, as explained above, the knife carrier 2 has passedstop 18 so, upo'n closing of switch 120, as the knife carrier'2 moves backward it is engaged and stopped by stop 18. Pin 8a at this point has just reclosed switch 12d byreturning lever 12d to its original position. The device is therefore back to its original position and in position such that depression of switch 120 will set the cycle in motion again.

The invention does not limit the use of the clutch arrangement to shears of the kind mentioned and it may be used in any types of machine drives in which the regular working rhythm necessitates exactly adjusted initial positions for moving machine elements.

It is also within the scope of the invention to use other change-over clutches instead of the electromagnetic friction clutch described in the example.

Moreover, a particularly notable application of the invention is for the return adjustment of the knives to take place through a, for example, electromagnetic clutch which is inserted in the drive for the rotationally movable magnetic disc 11, This enables a continuous drive to be employed for the magnetic disc, the second clutch being incorporated in the electric control system.

I claim:

1. An electromagnetic change-over clutching arrangement for a machine drive of the type in which a shaft means is to be controlled in rotation with respect to a continuously running motor and with respect to a predetermined initial shaft position comprising a first electromagnet means including a housingstructure having a.

first clutching surface mounted for rotation on said shaft means, a secondcoaxial electromagnet means having a secondclutching surface mounted for rotation with said motor, said second clutching surface being spaced axially from the first, a magnetic attractable disc'means slidably keyed to said shaft and axially movable between said surfaces, controllable means opeIr-atively coupled in driving relation with said first; electromagnet means whereby axial movement ofsaiddisc means in respect to, energization of said second mentioned electromagnet means frictionally couples said shaft to the motor to move the shaft from the initial position anddeenergizatio'n of said second electromagnet means and energization of the first, axially moves said disc means in the reverse direction and frictionally couples said shaft tosaid first electromagnet means so that movement imparted thereto restores said shaft to the initial position.

2. An electromagnetic changer-over clutching arrangement as claimed in claim 1, and further including means driven by said shaft, and stop means mounted for movement into and outof position relative to, the path of movement of the means, driven by the shaft, and operative to halt the same and thus the shaft in. said initial position.

3. An electromagnetically operated change-over clutching arrangement for shear means for subdividing travelling lengths of material and which shear means are adapted to be driven by a continuously running motor comprising a first clutch disc driven by the continuously running motor, a housing connected with said disc, a magnet means within the housing, a driving shaft o'perably coupled with the shear means, a coupling disc mounted in said shaft for axial movement therealong, said coupling disc being adjacent to but normally spaced from said first clutch disc whereby when said magnet means is energized said coupling disc is pulled by said magnet means into engagement with said first clutch disc to frictionally couple the shaft with the motor to actuate the shear means, a braking disc rotatably mounted on said shaft adjacent said coupling disc on the side thereof opposite said first clutch disc, a housing connected to said braking disc, a magnet means within the housing operative upon energization to axially move said coupling disc into frictional engagement with said braking disc and a controllable motor means operably connected to said braking disc for selectively holding the braking disc stationary or turning the same backwards for restoring the 'shear means to an initial position,

References Cited in the file of this patent UNITED STATES PATENTS

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