US 2403912 A
Description (OCR text may contain errors)
July 16, 1946.
F. A. po| PRESS oPERAT" DEVICE Filed Jan. 17, 1944 INVENTOR. fm2/c p/J BY Patented July 16, 1946 PRESS OPERATING DEVICE Frank A.. Doll, Detroit, Mich., assigner to Link Engineering Co., Detroit, Mich., a partnership composed of Herbert W.
and Frank A. Doll Link, Martha F. Link,
Application January 17, 1944, Serial N o` 518,523.
This invention relates to automatic presses and particularly to an automaticv press of a combined hydraulic and air-operated type which produces rapid movement of the press bed to and from operating position.
When a rapid movement of the press bed was required of hydraulic presses supplied heretofore in the trade, it was the practice to supply a, pump capable of delivering a large volume under high pressure which was expensive to manufacture and operate.` For this reason, most of the presses were furnished without the quick bed operating feature sothat a much smaller pump at materially reduced cost could be furnished.
It is one object of the present invention to provide an automatic press with a rapidly operating press bed, the movement of which is produced without the use of a hydraulic pump,
It is a further object of the invention to employ equipment which is actuated by air at a relatively low pressure for applying a high static pressure to the press bed when in operating position and for rapidly returning the bed to its initial position.
1t is a still further object of the invention to apply air to a fluid in a reservoir for displacing the i'luid and rapidly raising the bed of the press to operating position and after disconnecting the reservoir from the press to apply the air to a piston of a booster for materiallyincreasing the 31- pressure on the trapped iluid in the press for applying an increased pressure on the bed. i It is a still further object of the invention` to include in the electric control circuit Va time con-1 trol device which controls the duration of operation of the press and which thereafter operates the control elements to produce the rapid return of the bed to its initial position.
Other objects and features of the novelty of the invention will be specifically pointed out or will become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawing, wherein Figure 1 is a broken sectional View of a press and the operating and control mechanism therefor, embodying features of this invention;
Figure 2 is a schematic diagram of the control circuit employed in connection with the structure illustrated in Fig. l,
A press IU of conventional form embodies a base II having therein a cylinder I2 in which a ram or piston I3 projects. The ram or piston is sealed within the cylinder by a packing gland I4 Gil oi. conventional form. The piston supports a bed 55 I5 guided on a plurality of standards t3 and urged downwardly to its lowermost inoperative position by springs I1 provided about the stand-- ard and disposed between the bed and the head i5 of the press. Die elements I9 and 20 are mounted on the headand bed respectively, being secured in position thereon by suitable bolts 2 I.
A tank 22 provides a reservlor for the oil 23, or other liquid employed for raising the bed I5. The tank is connectedby a Ipassageway 24 through a valve 25 to passageway 26 which is joined` by a conductor 2l to the lower part of the cylinder I2.:
The passageway 26 is joined to a cylinder 28 in which a ram 23 is operatedby a piston 3| in adouble acting -cylinder 32. The lower part ofthe cylinder 32 is :joined to a conductor 33 whichzis also` joined to the upper part of a cylinder 34 in which the valve 25 operates.
The conductor 33 is joined to a valve housing 35 in which valves 36 and 31 operate, The upper part ef the cylinder 3-2 is joined to thewvalve housing 35 by a conductor 3B `which is joined to a conductor 39 that is attached to the lower part of the cylinder 34. The head 4I of the tank 22 is joined by a conductor "42 to a passageway 43 in the valve housing 35. The passageway 43 Ais connected to atmosphere through a passageway- The platform I5 oi the press I0 is provided.
with a boss '58 in which a switch operating rod 5l ls adjustably secured by a screw 58. Substantially at the end of the upward movement of the bed l5 the rod 5l contacts a switch operating plunger 59 for operating a micro .switch 6I for breaking the circuit through a con-tact B2 and completing the circuit through a contact B3. time controlled relay lill is mounted on the head i8 of the press, or .at some other suitable location, for regulating the of operation of the pressA A starter switch '5% and astop switch 65 are also mounted on the press at a point convenient to the operator.
When the starter switch @5 is pressed to closed position, relay contacts Eli are closed and are maintained closed through the energization of the relay solenoid 68. At the same time current will flow through the pilot coil 69 of the time control unit 64. This results in the closing of the contacts 69 which will remain closed through the energization of the unit 64 for an adjustable time period independent of the continued energization of the `coil 69, the adjustment being made through the setting of the lever 17. The closing of the contacts 68 also energizes the solenoid 53 which operates the valve 36 to the right against the tension of the spring 52. Air is conducted through the passageway 43 and conduit 42 into the tank 22 to apply a pressure of air to the top of the oil or other liquid 23. This forces some of the liquid out of the tank through the passageway 24 past the valve 25, which latter is moved to the bottom cf the cylinder 34 by the passage of the air past the valve 31 and through the conduit 33. The liquid iiows through the passageway 25 and conduit 21 to the bottom of the cylinder l2, which forces the piston or ram I3 upwardly until the die elements I9 and 23 are in engagement with each other. As the die elements I9 and 20 are about to come in contact with each other, the rod 51 engages the plunger 59 of the switch 6I to move the contact 62 to open position and to move the contact 53 into closed position.
The opening of the Contact 32 de-energizes the solenoid 68 and opens the relay contacts 682, which .deenergizes the solenoid 53 and permits the spring 52 to move the valve 35 to the left and exhaust the air in the tank 22 through the passageway l13. The closing of the contact 63 energizes the relay solenoid 'I4 which closes the contacts 142 and which in turn completes a circuit to the solenoid 55. The solenoid 55 operates the valve 31 to the left against the tension of the spring E f This connects the conductor 33 tothe atmosphere through a passageway 'l5 and connects the air from the passageway 43 to the passageway 38 'which operates the valve 25 to close off the passageway 26 from the passageway 24, thus preventing a flow of liquid from the cylinder I2 to the tank 22.
The air also passes into the top portion of the cylinder 32 to move the piston 3| downwardly. This moves the ram 29 into the cylinder '2t and displaces the fluid therein, which build up a pressure in the" cylinder I2, from the passageway 26,`
conduit 2'! and the cylinder 28 to exert increased pressure upon the piston or ram I3 and increase the pressure between the die elements I9 and 20. The pressure that is created in this manner is proportional to the air pressure times the square of the diameter of the piston 3| divided by the square of the diameter of the ram 29. This ratio can be made anything desired to produce a desired amount of pressure between the die elements.
After this increased pressure has been applied for a predetermined time, the time control unit 54 operates to open the contacts 69 and its operation is interrupted. The opening of the contacts 69 de-energizes the relay coil i4 which opens the contacts 14 and de-energizes the solenoid 55.' A spring 54 returns the valve 31 to the right and the air below the piston 25 passes through the conductor 39 to atmosphere through a passageway 18. Air from the passageway e8 passes into the conduit 33 into the lower portion of the cylinder 32 and the upper portion of cylinder 34 to move piston 3l upwardly and the valve 25 downwardly to permit the fluid in the cylinder I2 to ow into the tank 22. The springs I1 rapidly move the bed I5 of the press toits lowermost position.
The pressure of air produced by the pump may vary from to 125 pounds so that the conventional air pressure equipment may be employed to actuate the press. With the automatic control feature herein provided, the structure is admirably adaptable for operating presses with heated dies for curing plastic material as the material is molded into predetermined form. The regulating valve in the air supply line maintains the pressures constant and the time relay controls the duration of application of the pressure so that the operations are accurately repeated. Other types of presses, such as welding presses, are similarly beneted by the use of the operating and control mechanism herein illustrated and described. With this mechanism, hand operated presses are readily converted to quick acting automatic presses with a minimum of expense.
What is claimed is:
l'. The combination with a press having a bed mov-able into operative position, springs urging said bed toward inoperative position, a ram on said bed extending in a cylinder for moving said bed to operative position, a liquid in said cylinder, a reservoir for said liquid connected to said cylinder, a valve in said connection, a booster connected to said cylinder, an air-actuated piston operating said booster, a source of air under pressure, a solenoid valve for directing the air to the reservoir to move a portion of the liquid into the cylinder to advance the bed to operative position, a second solenoid valve, means when the bed is substantially in operative position for actuating said solenoid valves to operate the iirst said valve for cutting off the ow of liquid between the cylinder and reservoir, for connecting the air to the piston of the booster for increasing the pressure exerted by the bed and for removing the pressure of air from lthe reservoir, anda time control device which reverses the ow of air on the booster piston and operates the iirst said valve to connect the cylinder to the reservoir to permit the springs to quickly return the bed to its inoperative position.
2. The combination with a press having a bed moved by a ram in a cylinder to operative positionfa reservoir for a liquid, a booster connected to the cylinder and solenoid operated control valves for a source of air, of a controlv circuit which includes a normally open starter switch, a relay shunting said switch, a normally closed switch in circuit with said relay, one of said' solenoid valves also being in circuit with said relay and actuated to connect the air supply to the reservoir the liquid in which moves the bed to operative position, a normally open switch actuated to vclosed position when the press is moved to operative position, which movement also opens said normally closed switch and deenergizes said relay and first solenoid valve, a second solenoid valve actuated by the closing of said second switch to connect the air to the booster and for disconnecting the cylinder from the reservoir, and a third switch for opening the circuit to the second solenoid which reverses the flow of air on the booster and connects the cylinder to the reservoir to permit the press to qUCkY'reU-ln UO i11- operative position.
3. The combination with a press having a, bed moved by a ram in a cylinder to operative position, a reservoir for a liquid, a booster connected to the cylinder and solenoid operated control valves for al sourcel of air, rof a control circuit which includes a normally open starter switch, a relay shuntim-,r said switch, a normally closed switch in circuit with said relay, one of said solenoid valves also being in circuit with said relay and actuated to connect the air supply to the reservoir the liquid of which moves the bed t0 operative position, a, normally open switch actuated to closed position when the press is moved to operative position, which movement also opens said normally closed switch and deenergizes said 1 relay and irst solenoid valve, a second solenoid 6 valve actuated by the closing of said second switch to connect the air to the booster and for disconnecting the cylinder from the reservoir, a third switch for opening the circuit to the second solenoid which reverses the ow of air on the booster and connects the cylinder tothe reservoir to permit the press to quickly return to inoperative position, and a timing device for operating said third switch for controlling the duration of operation of said press. l
FRANK A. DOLL.