US 2429387 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Oct. 21, 1947. BUCHHElM Q 2,429,387
METAL-WORKTNG MACHINE Filed Nov. 18, 1944 3 Sheets-Sheet 1 INVENTOR. 41/5527 BUCHHf/M Oct. 21, 1947. v um- 2,429,387
METAL-WORKING MACHINE Filed Nov. 18, 1944 v 3Sheets-Sheet .2
INVENTOR. 145Efi7 BU HHE/M 1947- A. BUCHHEIM METAL-WORKING MACHINE I Filed Nov 18, 1944 s Sheets-Sheet s INVENTOR. 4
Patented Oct. 21, 1947 METAL-WORKING MACHINE Albert Buchheim, Brooklyn, N. Y., assignor to Hercules Electric & Manufacturing 00., Inc., Brooklyn, N. Y., a corporation of New York Application November 18, 1944, Serial No. 564,049
This invention relates to an improvement in cold metal working machines of various types in which metal sheets and bars are bent, punched, drawn, or otherwise shaped.
The object of the invention is to provide an improvement in machines of this type whereby the metal being operated upon is retained in correct position for the next operation of the machine by magnetic means, without the necessity of the operator holding the metal being shaped in position.
In the operation of power brakes, bending machines, punching and drawing machines, and other machines involving stamping, drawing, punching and bending of metal, it is customary for the operator to insert the metal in proper position in the machine, which proper position is usually determined by an adjustable gauge bar, and to hold the metal in position during the operating stroke of the machine, so that the metal is bent, punched, drawn, or otherwise shaped, as desired.
When the piece being operated on has been shaped, punched or bent to the desired degree, it is removed and a new piece is fed into the machine for similar operation. The new piece may be an entirely separate piece or part of a continuous strip from which the precedingly formed section has been severed. Normally, this feeding and positioning of the metal in the machine involves certain dangers to the operator. If the operator inadvertently permits his fingers or any portion of his body to remain in the path of the machine, serious injury may result, and in the bending and shaping of heavy metal the part projecting outside of the operation of the machine is often jerked, tugged or bent by the machine operation, so that the operator holding on to this portion may have it wrenched from his hands and may sustain injury in this way.
It is the object of the present invention to provide magnetic means for positioning and holding the metal in the desired position in the machine, which magnetic means will permit the metal to be fed into the machine and positioned against the gauge bar and which magnetic means will hold the metal in position during the operating stroke of the machine and may be released to permit ready removal of the formed sheet from the machine when the forming operation has been completed.
Another object of the invention is to provide a metal Working machine with magnetic holding means, whereby a plurality of small pieces of metal may be retained in position during an perating stroke and all be bent, punched or deformed to the desired degree in one stroke of the machine. I
Another object of the invention is to provide for the greater safety of workmen operating metal working machinery, so that they do not have to hold the metal being operated upon in position and therefore have no occasion to have their fingers or other parts of the body in a position where injury may result.
Various other objects and advantages of the invention will be apparent as this description proceeds.
In the accompanying drawings, I have shown illustrative embodiments of the application of my invention to a power brake, and a punching, shaping or drawing press. It will be understood, however, that the application of the invention is not limited to these specific embodiments, but that it may be applied to all cold metal working machinery which operates on magnetizable metal, and in which the metal must be inserted in a given position for proper operation of the niachine.
Figure 1 illustrates a perspective view of a power brake or metal bending machine to which my invention has been applied.
Figure 2 is a sectional view along the 1ine-2-2 of Figure 1.
Figure 3 is a sectional view illustrating the application on a metal cutting machine.
Figure 4 is an illustration of the application of the invention to a punch press which may also be a shaping press.
Figure 5 is a diagrammatic illustration of one form of wiring diagram which may be used in machines of this kind.
In the form of embodiment illustrated in Figure 1, the machine illustrated is generally known as a power brake. The machine constitutes a frame I, having a stationary die or shaping member 2 and a, reciprocating die or shaping member 3 driven from a driving mechanism 4 controlled by a clutch 5, which is operated through a lever and linkage system 6 connected to a foot treadle I, so that when the operator presses the foot treadle, the upper or reciprocating member 3 is brought down against the die member 2 to bend the sheet metal to the desired shape.
Machines of this kind are well known in the metal working industry and their construction and operation will be readily understandable to persons skilled in the art.
The lower die member 2 and the reciprocating upper die member 3 may take diii'erent configurations to give difierent bends to pieces of sheet metal being operated on in machines of this kind. Normally, the metal to be operated on is fed into the machine from the front against an adjustable gauge bar 8 which is adjustably clamped in the machine by clamp 8a or other suitable clamping means. The position of the gauge bar determines the position of the metal in the machine. The metal is normally held in the hand against the gauge bar while the foot treadle I is depressed to cause the clutch 5 to engage with the driving mechanism which causes the reciprocating portion 3 of the die to be brought down in a power stroke to strike and bend or depress the metal into the lower die member 2. Depression of the foot treadle 1 causes the machine to go through one operation of driving down and again raising the upper die member 3 and then stop, after which the formed metal may be removed and a new piece inserted.
In the operation of a machine of this type according to my invention, the gauge bar 8 is magnetized by means of one or more electromagnets 9, which are adjustably located against the gauge bar 8 and which may be suitably shaped as either round or rectangular magnets to magnetize the gauge bar along its entire length. The magnets 9 may be mounted on adjust-able supports I which may be raised or lowered as indicated, or may be moved forward or backward to contact gauge bars of difierent width or thickness, or the electromagnets may be mounted on the frame of the metal working machine itself.
The current to the electromagnets is controlled by means of a wiring diagram similar to that illustrated in Figure 5, which diagram will be described later, in which the current to the electromagnets is out 01f during the upstroke of the machine to remove the magnetic holding effect and permit the formed piece to be removed from the machine.
The force of the electromagnets can be controlled by means of a rheostat or series resistances, so that the magnetic force will be strong enough to hold the metal sheet II in the machine after the operators hands have been removed from the machine but weak enough to permit the sheet to be shifted by the operator in the event shifting is necessary to correctly position it in the machine.
The use of the magnets 9 to magnetize the gauge bar 8 also tends to pull the metal sheet firmly and evenly against the gauge bar throughout its entire length and insures better positioning of the sheet in the machine than occurs where the operator alone holds the sheet II against the gauge bar. Where a plurality of small sheets are to be shaped at the same time, it is possible for the operator to arrange the entire series against the gauge bar and have them held by the magnetic force so that they all may be shaped or bent in one operation; whereas if it is necessary for the operator to hold each individual sheet against the gauge bar, the number of sheets which can be bent or formed in one operation is limited to the number that the operator can hold in his hands.
As illustrated in Figure 2, the shape of the upper and lower dies 2 and 3 is such as to give an ordinary V bend to the sheet being operated on, and it will be understood that rounded, zigzag or any other shape can be given in the operation of a machine of this kind.
15 reference to the shear.
50 ing press by means of clamp screws 21.
4 In the application of the invention illustrated in Figure 3, the machine is used for cutting or severing measured widths or lengths of metal from a sheet. The sheet I2 is fed forward along 5 the bed I3 of the cutting machine until it contacts the adjustable gauge bar I4 which, in the embodiment illustrated, is in the shape of an angle iron and determines the length or width of the portion of the sheet which is to be cut-off.
The gauge bar I4 may be adjustably supported on a pair of angle brackets I5a mounted on the machine and located outside the path of the movable shear blade I6. C-clamps Ma may be used to adjustably position the gauge bar with The stationary shear member is indicated at I5 and the movable shear at I6. The movable shear is located between the brackets I5a which support the gauge bar I4.
The holding members I! engage the sheet slightly in advance of the engagement of the shear I6 to hold it in position during the cutting operation. The gauge bar I4 is magnetized by the magnet I8 which is adjustable so that it can always be brought into contact with the adjustable gauge bar I4, to hold the sheet in position against the gauge bar by magnetic attraction. Means may be provided for automatically disconnecting the power to the magnet to permit the severed sheet to be dropped as soon as the cutting operation has been completed. The operation of the magnet, however, holding the sheet i2 against the gauge bar I4 insures that the sheet will be held firmly against the gauge bar and prevents bending, curling and other deformation 5 of thin sheets which cannot be clamped during a cutting operation.
In the application illustrated in the embodiment of Figure 4, 20 represents the bed of a punch or forming press which carries a die 2I 40 and a reciprocating forming head 22 mounted on a reciprocating platen 23. It will be understood, of course, that the upper member may be the stationary member, and the lower member the reciprocating member in machines of this kind.
The sheet 24 to be operated upon is positioned against an adjustable gauge bar 25 which may be shifted and clamped in position to correctly position the sheet 24 within the punching and form- The gauge bar 25 is magnetized by one or more electromagnets 26, which may be adjustably positioned to abut gauge bars of different width, which may be clamped in the machine, as in the operation of the machine illustrated in Figures 1 and 2. When 55 ejected if the machine operates to automatically eject the formed pieces. As soon as the forming die has reached the upper limit of its stroke, the current to the electromagnets is automatically re-established in accordance with the wiring dia- 7 gram to be described hereinafter, and the machine is ready for the insertion and positioning of another sheet 24, to be operated upon.
As illustrated in the wiring diagram, Figure 5, current under the normal line voltage is fed from the A. C. lines 30 and 30a, where it is rectified to direct current and fed into the D. C. line under a lower voltage. The voltage may be varied as desired.
The rectifier may include a rheostat or step down transformer, indicated at 32, by which the amount of current fed into the D. C. line may be controlled to control the force of the magnets. The D. C. line 33 preferably includes a manually controlled switch 34 located on the front of the machine whereby the operator may connect or disconnect the current to the magnet or magnets 35. Normally, this manually controlled switch is left in closed position during the operation of the machine and is disconnected at night or during the periods of idleness of the machine. In an emergency during the operation, the operator may readily disconnect the manual control switch 34 to take the power off the magnets. The D. 0. line 33a. passes through an automatically controlled switch 36 which remains closed during the working stroke of the machine and is automatically opened during the return stroke of the reciprocating portion of the machine by means of a mechanically operated limit switch diagrammatically illustrated at 31. This limit switch 31 operates the switch 36 through a solenoid coil 36a which is energized when current from the A. 0. line 38--38a. flows through the limit switch 31. By this means current through the contactor 36 may be automatically interrupted on the upstroke of the machine to de-energize the magnets 35 and permit the formed sheet to be removed by hand or automatically ejected or to drop from the forming machine and may be automatically restored when the machine is ready for the next operation.
The arm 31a of the limit switch 37 diagrammatically illustrated in Figure 5 may be connected to one link of the toggle 601. by which the clutch member 5 is caused to engage or may be operated by the reciprocating head. The limit switch is so adjusted that when the upper die member 3 is at the top of its stroke and the machine is idle the magnets 9 will be energized so as to hold any sheet or bar of metal placed against the gauge bar 8. The magnets 39 or 9 will continue to be energized during the down or working stroke of the upper die member 3. When the bending or deformation of the sheet II has been completed the limit switch will be moved to a position which de-energizes the magnets during the upstroke of the die member 3 to permit the formed sheet to drop or be removed from the machine.
While I have illustrated certain preferred forms of embodiment of my invention, it is to be understood that the invention is applicable to various types of metal working machines which operate on magnetizable metals and that various modifications in the form and application of the invention may be made within the scope of the claims attached hereto.
1. In a metal working machine, a frame, a stationary die member on the frame, a movable die member and an elongated gauge bar to determine the position of the metal within the machine, said gauge bar being adjustably clampable to said frame, and an electromagnetic means for engaging and magnetizing the gauge bar to hold metal against the guage bar itself as the machine commences to operate upon the held metal.
2. In a metal working machine, a frame, a stationary die member on said frame, a movable die member and an elongated gauge bar to determine the position of metal to be worked upon by said die members said gauge bar being adjustably clamped to said frame, an electromagnetic means for magnetizing the gauge bar itself to hold metal against the gauge bar, means to actuate the machine to bring the movable die member against the stationary die member when metal to be worked upon is between said members and held by said magnetized gauge bar, and means to automatically disconnect the electromagnetic means when the metal is ready for removal from the machine to release the hold of said magnetized gauge bar thereon.
3. In a metal shaping machine, a frame, a stationary die member, a movable die member, an elongated gauge bar, means to adjustably clamp said gauge bar on said frame, electromagnetic means movable against said gauge bar to magnetize the same, said gauge bar holding the metal to be worked upon against itself, means to actuate the machine to bring the movable die member against the stationary die member when metal to be worked upon is between said members and held by said magnetized gauge bar, and
switch means operating during the return stroke of the upper die member to cut off current to said electromagnetic means to release the hold of said magnetized gauge bar on said metal.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 364,259 Keene June 7, 1887 468,586 Walsh Feb. 9, 1892 666,196 Howe Jan. 15, 1901 1,424,831 Kux Aug. 8, 1922