US2073238A - Press - Google Patents

Description

March 9, 1937- A BYERLElN 2,073,238

PRESS Filed April 14, 19 34 2 Sheets-Sheet l MMM 4' krz/ Gttorneg March 9, 1937. A. A. BYERLEIN PRESS Filed April 14, 1934 2 Sheets-Sheet 2 |||r Llll Q 3nne ntor (Ittorneg Patented Mar. 9, 1937 PATENT OFFICE Arthur a Byerlein,

General Machinery Ohio, a corporation of PRESS Detroit, Mich., assignor to Corporation,

Hamilton, Delaware Application April 14, 1934, Serial No. 720,51

6 Claims. (01. 1 13-38) This invention relates to power presses and more particularly to presses for drawing sheet metal or the like.

One object of the invention is the provision of a power press having a work 'plunger or slide which is so driven as to operate at comparatively speed during the work forming part of a cycle of operations and at ahigher rate of speed during. the major portion of the remainder of the cycle. Another object of the invention is the provision of a press for drawing or working metal, having a variable speed electric motor drive for the work Fig. 3 is a diagrammatic showing of the electrical control system; v

Fig. 4 is a partly diagrammatic view, of the controlling switches and their operating cams,

- and Fig. 5 is a diagrammatic the timing of the'various speedchanges.

Conventional drawing er minute, but then the total production in any given time period will also be reduced. In accordance with the present invention, however,

the operating shaft by means of which the movable slide is driven, is so operated that the speed of the plunger is materially slower during the drawing part of a cycle of operations in order that a comparatively high numberof strokes per minute is attained without correspondingly increaring the speed of the drawing operation itself.

The press maybe of any suitable character having a movable slide which carries a die for drawing the work, and may be equipped with the usual illustration showing serving as blank holding members, forming mem- As herein shown the press is provided with a plurality of mechanically operated upper 5 slides H and I2 and the mechanically operated 7 lower slide 42 which are moved in timed relationship as more fully set forth in my prior United States Patents Nos. 1,768,503 and 1,967,464.

Referring more particularly to the drawings I0 10 the shaft 20.

id with the two dwelling it may blank holder together with the lower portion of themes Such lower die may be operated by means of the lower the carrying shde designated generally 42 Slide 42 is guided for vertical movement its opposite ends being connected to operating rods48 the 55 upper ends of which are formed as eccentric straps 49 engaged with cylindrical surfaces 48 eccentrically provided adjacent opposite ends of the operating shaft l3. 5 The motor 2| which serves as a driving force for the operating shaft 13 by means of which the various slides are reciprocated in timed relationship is a two-speed electric motor of com-.

paratively high horse power capacity so that the motor can pull the press through its'peak loads without requiring the storing of energy in a large flywheel. A flywheel of substantial size would prevent rapidly changing the speed of operation of the press at predetermined points in the cycle 15 of operations, so it is preferred that no flywheel be employed. Mounted on the press frame at a suitable location is a cam shaft 50, operated by a timing sprocket chain 5| from the operating shaft l3 so that the shafts 58 and I3 will move in synchronism and at the same speed of rotation. The cam shaft 50 is provided with a number of cams 52 to 51 inclusive as shown in Fig. 4 for the operation of switches proper times in the sequence of press operations. The electric motor 2| is provided with a high speed'winding connected to the leads 85 of a three-phase power supply and also with a low speed winding connected through the leads 68. Power switches 81 and 68 respectively complete the connection to the power source 88. It will be understood that when the switch 68 is closed, the motor is operated at low speed andwhen the switch 81 is closed and switch 68 opened the motor will operate at high speed. The high speed of operation is such as to give a desired high speed movement of the press parts for the ineffective portions of a cycle of operations, while the low speed of the motor is suitable to provide a drawing speed that will be slow 'enough so 40 that there will be a minimum amount of breakage in drawing the metal.

As shown in Fig. 5, the motor is automatically controlled by means of the cams 52 to 51, the switches 58 to 83 and the additional apparatus shown in Fig. 3. The press may be started by the operator and the operating shaft 13 will then be driven at high speed from the point a to the point cm Fig. 5, point c being about 80degrees from point a. From the po" t c'to the point d, an angle corresponding substantially to the drawing or effective operations on the metal, the shaft moves at low speed. From the point 12 which is about 190 degrees from point a, the shaft moves at high speed until it has rotated a total of about 340 degrees up to the point e.

point e to the point I which is about 350' degrees from point a the shaft moves at low speed and at the point I the brake is applied so as to stop the shaft when point a is again reached.

As an example'of the essential parts of the motor controlling means, Fig. 3 illustrates diagrammatically the electrical connections that may be employed. The power source 89, I as shown, is connected to a small motor 88 which drives a low voltage generator ll. The generator Hi supplies current for .the low voltage or controlling system. l2.is a main switch and energizes the'low voltage system. 13 and 16 are two manually operated switches adaptedto be simultaneously operated by the two hands of the attendant to initiate a cycle of operations. When the switches 18 and 14 are both closed by the attendant, a circuit is completed from the generator it through switch '52, across contact '35, through a normally-closed switch 82, through 58 to 63 inclusive atswitch 83 which is normally closed and through the coils 16 and 11 of the low voltage circuit breakers l8 and 79 respectively. When the circuit breaker coils are thus energized the circuit breaking elements complete their respective circuits, the breaker 19 being provided in a reset circuit 80 and the breaker 18 being arranged to connect one side of the low voltage source to'a lead 8|. With both switches 13 and I4 closed current may flow from the lead- 8| across the closed contacts 83 and across the closed contacts '84 to a winding 85, this winding having an armature which closes the switch 81 of the motor 2i and holds the switch '81 closed as long as the winding 85 is energized. A suitable overload circuit breaker 88 may be employed in series with the winding 85.

When the attendant closes the. switches 13 and 14 the motor 2| is thus connected so as to operate at high speed. The operator holds the switches 13 and Id closed until the crank shaft has moved some distance, up to the point I) of Fig. 5 for example, at which point the switch 58 is closed by cam 52. When the switch 58 closes a holding circuit through the lead 81 is completed maintaining the coil 85' energized and permitting the operator to remove his hands from the two switches 13 and 15. The closed connection across the switch 58 maintains the motor in operation at high speed until the point e is reached after about 80 degrees total travel of the operating shaft l3. At this point the switch 58 is automatically opened by its controlling cam, and switch 60 is closed by cam 54. The switch 60 connects the lead 81 to a winding 80 having an armature which closes the switch 68 of the motor 2! and which holds the switch 88 closed as long as the winding 98 is energized. The switch 58 being opened has deenergized the winding 85 and thus opened the switch 61. The motor will therefore operate at its low speed of movement throughout the drawing part of the cycle of operations, up to the point d about degrees displacement from the initial point a. At the point (1, the switch 68 is automatically opened to deenergize the winding 88 and thus open the switch 88 and at the same time the switch 59 is automatically closed so as to again energize the winding 85 and cause the motor to operate at high speed. The motor continues moving at high speed from the point d to the point e which is about 340 degrees from point a. At the point e the switch 59 is opened automatically and switch 6| is closed so that the speed of the motor is changed from high speed hack to low speed. The motor moves at low speed for about 10 degrees movement of the shaft l3, up to the point Land at, the point i the.

switch 58 opens and switch 82 closes. When the switch 62 closes both of the switches 81 and 88 of the motor 25 are open, and a stopping force is applied to the shaft i8 through a suitable brake by means of an armature controlled by a winding 9! which is in series with switch 82. The circuit is completed through the winding 9! through switch 82 and across the contacts. 83 which are now closed inasmuch as the operator has previously released his hand from the switch 13 and permitted the return movement of the switch to its position shown in Fig. 3. The press will thus stop automatically after a complete cycle of operations the shaft i3 having moved through a total of 360 degrees and again returned to its starting position a.

At the same time switch 82 closes for the app ication of the brake, the switch 63 also opened 15 through another cycle.

automatically by the cam 51, switch 63 remaining open, however, only instantaneously, this switch without requiring a complete cycle of operations 20 before stopping.

It will now be apparent that when the operator so desires, he can start the press in operation,

tion, the drawing slide is moved comparatively work is thus avoided.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that th ment of the slide.

6. and

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