US2052795A - Two-hand control system - Google Patents

Description

Patented Sept. 1, 1936 PATENT OFFICE TWO-HAND CONTROL SYSTEM I Edward D. Rapisarda, Azawam, Mass of one-halt to George E. Byford,

assignor Winchester,

Application March 23, 1935, Serial No. 12,749

6 Claims.

This invention relates to control systems particularly designed for presses such as laundry presses in which it is important to insure that the operator will have both hands out of the way of the press members during their closure. One object of the invention is to provide a simple control system applicable to motive power means of various types, but particularly applicable to those cases in which the motive power mechanism is operated by a reversible electric motor, and in which both hands of the operator will be required to be present on the controls during the complete closure of the press members, thus efiectively preventing one hand becoming caught in the press. Another object is to provide a control system in which the closing movement of the press members can be stopped or reversed at any time at the option of the operator, so that it is not necessary to take the time for the press to completely open if a mere stoppage of the closing movement is all that is required. Another object is to provide a control system in which the reversal of the movement of the press members can be accomplished by a momentary pressure upon the reverse control button, the press continuing to open even if the operator releases the button at once; thus relieving the operator of the necessity of continuing attendance throughout the entire opening operation. A further object is to provide a control system permitting the opening of the press to be initiated by a control situated at a remote point, offering an opportunity for the operator to open the press while working at another machine, or providing a safety means by which other operators or a supervisor can open any press from any desired control station. Additional objects will appear from the following description and claims.

Fig. 1 shows in diagrammatic form the circuits by which my invention is realized in its preferred form; and

Figs. 2 and 3 are diagrammatic views of a press operating means to which my'invention is especially applicable.

The preferred embodiment of the invention utilizes a press actuating mechanism driven in any desired way by a reversible electric motor, one type of press operating means being described in my copending application Serial No. 10,344 filed Mar 9, 1935, and illustrated diagrammatically in Figs. 2 and 3. The principles of the invention could be employed to advantage in other types of installation involving for example electrically operated valves, and possesses distinct advantages in other types of mechanism than laundry presses. For convenience in description, however, the invention will be considered as being applied to a laundry press driven by a reversible electric motor through a positively acting hydraulic pressure mechanism. 5

The main power line is shown at Ill, being provided with the usual main switch II by which current can be cut ofi from the entire control and operating mechanisms. One branch l2 of the power line leads from the switch II to a contact point l3 adapted to be engaged by a contactor 14 of a solenoid relay I5. This relay, which is of a standard commercial type, has an armature l6 controlled in its movement by a solenoid ll. A secondcontact point l8, also positioned for en- 15 gagement by the contactor I4, is joined by a line IS with a terminal on the motor 2|. A second terminal 22 on the motor, forming with the terminal 20 the normal or'press closing circuit, is joined by a line 23 with a contact point 2t. This 20 contact point, together with a companion contact point 25, is positioned for engagement by a second contactor 26 also carried by the solenoid relay [5. Both contactors are arranged to emgage their respective contact points at the same time. The 5 contact point is joined by lines 2'! and 28 to that side of the power line opposite to that to which the contact point l3 was connected.

The press closing control circuit is continued from the line 12 by a line 29, 30 leading to contact 0 points 3| adapted to be bridged by a hand operated, normally open switch 32.. These contact points are joined by a line 33 to a second pair of contact points 35 adapted to be bridged by a similar hand operated, normally open switch 32, the 35 two switches being thus in series. A line 35 joins one of the latter contact points to a contact point 36 normally engaged by a contactor 31 carried by the armature 38 of a second solenoid relay 39. A contact point 40, forming a pair with 40 the contact point 36, is joined by a line 4| to the solenoid H, which in turn is joined by'a line 42 to the line 28 previously mentioned.

It will be seen that if one only of the hand operated switches 32, 32 is closed nothing will 45 happen since the circuit through the other switch is still open. If both of the switches are closed simultaneously, however, current will be permitted to flow through the contactor 31 and through the solenoid 11. This causes the arm of the relay Hi to rise, bridging the pairs of contact points I3, l8 and 24, 25 and allowing current to flow through the terminals 20, 22 of the motor 2|. The motor will thereupon operate in a direction to close the press. If either or both hands are removed from the switches 32, 32' the motor 2| will stop and the driven press element will come to rest wherever it may be. In contrast with automatically by some movable element of the press as the latter comes into closed position, which serves to short-circuit the two switches 32, 32' and thus relieve the operator from the necessity of holding down the control switches during that part of the operation of the motor which is concerned with maintaining pressure between the press elements as distinguished from causing a press closing movement.

The reversing solenoid relay 39 is provided with two pairs of contact points; 45 and 46, adapted to be bridged by a contactor 41; and 48 and 49, adapted to be bridged by a contactor 58. The contact point 45 is connected by a line 5| to the line 28. The contact points 46 and 48 are connected respectively by lines 52 and 53 to reversing terminals 54 and 55 on the motor 2|. The contact point 49' is connected by a line 56, 51 with the same side of the power circuit as the line l2. In order to actuate the solenoid relay 39 a line 58 is connected with the line 51, terminating in one of a pair of contact points 59 adapted to be bridged by a normally open hand operated switch 68. The other one of the pair of contact points 59 is connected by a line 6| to a contact point 62 which, with a companion point 63, is positioned to be engaged by the contactor 31 when the latter is raised off of the points 36, 48 by actuation of the relay 39. The point 62 is directly connected with the solenoid'64 surrounding the armature 38, and the solenoid itself is joined by a line 65 and a limit switch 66 with the line 28. The limit switch is set so as to be actuated byengagement with some part of the press, and is open when the press is in its fully open position and closed as soon as the press leaves that position.

Assuming that the press is in closed position and that the button 68 is depressed, current is allowed to flow through the lines 51, 58, 6 65 and 28 and the solenoid 64. The consequentraising of the armature 38 accomplishes two things. In the first place the contactor 31 is raised clear of the points 36, 48 and is brought into engagement with the points 82, 63. The breaking of the circuit between the former two points opens the circuit through the solenoid H which controls the forward movement of the motor 2| and therefore the closing of the press or its maintenance in'closed position. As long as the points 38, 48 are disconnected it will be impossible to produce any action whatever by manipulation of the buttons 32, 32. It should bev remembered that as long as the press is even partially closed the limit switch 66 is closed, so that a path for the current through the solenoid 64 is assured. At the same time-that the contactor 31 is raised clear of the points 36, 48 it is brought into engagement with the points 62, 63. The latter of these points is joined by a line 61 to the line 51, so that the bridging of the points 62, 63 by thecontactor 31 short circuits the hand switch 68 and renders it unnecessary for the operator to maintain that switch depressed. This is of considerable advantage in speeding up operations with the press, since a momentary pressure on button 68 is all that is necessary to cause the press to open fully.

' The second thing accomplished by the raising of the armature 38 is a bridging of the points 45,

46 and 48, 49 by the contactors 41 and 58 re-' spectively, which sets up a circuit through the upon fall, resetting the relay 39 in readiness for a further press closing operation.

One further capability of the circuits described relates to the remote control of the opening of the press, a feature useful both in permitting the operator to attend to a plurality of presses, leaving one press closed while operations upon another press are being carried on without the necessity of returning to the first press for opening it; and also in permitting a supervisor anywhere in the room to open all presses instantly from any desired location if any operator becomes caught ina press. This is readily accomplished by lines 18, 1| from the lines 6|, 58 of each press, adapted to be bridged singly or in any desired parallel relation by one or more normally open hand operated switches 12. This switch 12 operates exactly the same as the switch 88 previously described. The lines 18, 1| from several presses may, if desired, be bridged by a single multiple contact hand operated switch for simultaneous opening of the group of presses.

Figs. 2 and 3 show a press operating mechanism more completely described in my copending application above referred to, and especially suitable for use with the control system considered above. To one of the press elements is connected a hydraulic cylinder 13, the motive fluid for which is preferably oil. Within the cylinder is a piston 14 having attached to it a piston rod 15 connected to the other press element. A gear pump 16 is attached to the shaft of the motor 2|, or is otherwise coupled thereto, and is connected to the cylinder 13 through a port 11. A second gear pump 18 is also coupled to the motor, one shaft of the two pumps being preferably integral, and is connected to the cylinder through a port 19 at that end of the cylinder to which the piston moves as the press is closed. The other sides of the two pumps are joined by a conduit 88 which terminates in a port 8| at the opposite end of the cylinder. The conduit 88 is also joined through a one way pressure relief valve 82 to an oil reservoir 83.

With" the press open the parts will be in the position of Fig. 2. Starting of the motor 2| by the control system in the direction to close the press will cause rotation or the two gear pumps in a direction to withdraw oil from the lower end of the cylinder and to deliver it through the conduit 88 to the upper port 8|. The action of the pumps is at first additive causing motion of the piston at a comparatively rapid rate, until the piston passes the port 11. The pump 16 is then automatically rendered inactive as far as actual work done on the piston is concerned, the oil from this pump circulating idly through the port 11, the conduit 88, and the port 8| as indicated in Fig. 3. The smaller pump 18, however, continues its action of carrying oil from the bottom end of the cylinder to the top end, and therefore of continuing the motion of the piston but at a lower rate, until the press is fully closed. While the press is closed the motor 2| continues to operate,

and oil will be forced by the pump 18 through the relief valve 82 into the reservoir 83, a connection 84 with a check valve 85 in it being provided to permit continued circulation of oil from the reservoir through the pump 18. The resistance offered by the relief valve causes a continued pressure to be exerted by the pump 18 upon the upper side of the piston and thus to keep any desired degree of pressure upon the press.

From the description above it will be clear that if the motor is stopped at any time the stoppage of the pumps will cause the piston to be arrested in its movement, and the press to remain stationary in the position it is in when the main two hand control buttons are released. If the operator desires the press to open a momentary depression of the buttorrjli will cause the press to move continuously towards open position until the limit switch 66 is opened. If on the other hand the stoppage of the press was merely for the purpose of adjusting the position of the work, and it is desired to continue the closing of the press, the interrupted closing movement can be resumed at any time by again depressing both of the two hand control buttons 32, 32. Once the press has been substantially closed so that it is safe for the operator's hands to be free, it will be unnecessary to maintain pressure upon the buttons 32, 32 since the limit switch 43 has by this time shortcircuited these button switches. The advantages of the other features of the invention have been discussed above, and need no recapitulation here.

What I claim is:

d 1. A two hand control system for presses and the like comprising positive acting motive power means for closing or opening the. press, control means requiring the use of two hands of the operator for causing a continued press closing motion of the motive power means as long as said control means is engaged by both hands of the operator, the motive power means being rendered inactive and therefore retaining the press in its then position if either hand of the operator is released 1 from said control means separate one-hand manual control means for initiating press opening motion of said motive power means, and means activated by a momentary displacement of said separate control means from its normal position for causing continued press opening motion of the motive power means to complete press opened position.

2. A two hand control system for presses and the like comprising electrically operated motive power means for closing or opening the press, a relay controlling said motive power means for press closing movement, switch means requiring the use of two hands of the operator for causing activation of said relay, a second relay controlling the motive power means for press opening movement, separate switch means for said second relay, and means controlled by the activation of the second relay for rendering the first relay inactive.

3. A two hand control system for presses and the like comprising electrically operated motive power means for closing or opening the press, a relay controlling said motive power means for press closing movement, switch means requiring the use of two hands of the operator for causing activation of said relay, a second relay controlling the motive power means for press opening movement, separate switch means for said second relay, means controlled by the activation of the second relay for rendering the first relay inactive, and means controlled by the activation of the second relay for insuring the continuance of its controlling function until the press has been completely opened.

4. A two hand control system for presses and the like comprising electrically operated motive power means for closing or opening the press, a relay controlling said motive power means for press closing movement, switch means requiring the use of two hands of the operator for causing activation of said relay, a limit switch operated by the press when closed for causing continued activation of the relay irrespective of the manual operation of said switch means,'a second relay controlling the motive power means for press opening movement, separate switch means for said second relay, and means controlled by the activation of the second relay for rendering the first relay inactive.

5. A two hand control system for presses and the like comprising electrically operated motive power means for closing or opening the press, a relay controlling said motive .power means for press closing movement switch means requiring the use of two hands of the operator for causing activation of said relay, a limit switch operated by the press when closed for causing continued activation of the relay irrespective of the manual operation of said switch means, a second relay controlling the motive power means for press opening movement, separate switch means for said second relay, means controlled by the activation of the second relay for rendering the first relay inactive, and a second limit switch operated by the press when opened for rendering said second relay inactive.

6. A two hand control system for presses and the like comprising electrically operated motive power means for closing or opening the press, a relay controlling said motive power means'for press closing movement, switch means requiring the use of two hands of the operator for causing activation of said relay, a second relay controlling the motive power means for press opening movement, and a plurality of independently operable switches for activating said second relay, at least one of said-last named switches being situated remote from the press.

EDWARD D. RAPISARDA.

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