US3228193A

US3228193A - Fluid system with valve actuated pump motor switch

Info

Publication number: US3228193A
Authority: US
Inventors: Herbert H Schmiel; Louis G Hajma
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-11-05
Filing date: 1963-11-05
Publication date: 1966-01-11
Anticipated expiration: 1983-01-11
Also published as: GB1025089A; DE1426557A1; DE1426557B2

Description

Jan. 11, 1966 SCHMIEL ETAL 3,228,193

FLUID SYSTEM WITH VALVE ACTUATED PUMP MOTOR SWITCH Filed Nov. 5, 1963 w ll:

I IIIIIIIII 4 INVENTORS HERBERT H. BOHMIEL and LOUIS G. HAJMA ATTORNEYS United States Patent O 3,228,193 FLUID SYSTEM WITH VALVE ACTUATED PUMP MOTOR SWITQH Herbert H. Schmiel, Trailard Drive, Willoughby, Ohio, and Louis G. Hajma, 24800 Emery Road, Warrensville Heights, Ohio Filed Nov. 5, 1963, Ser. No. 321,611 Claims. (Cl. 6052) The present invention relates generally as indicated to a fluid system with a valve actuated pump motor switch and more particularly to a novel switch arrangement which energizes the electric drive motor for the system pump whenever the directional control valve of the system is shifted to an operating position whereat fluid under pressure delivered by the pump is conducted to a fluid motor.

It is a principal object of this invention to provide a fluid system in which the electric switch that controls energization and deenergization of the pump drive motor is attached on the directional control valve of the system for operation of the switch plunger by the movable valve element of the directional control valve.

It is another object of this invention to provide a combination directional control valve and electric switch so arranged that the switch contacts are closedto energize the pump drive motor while the pump outlet is yet in communication with the tank bypass passage of the valve whereby the motor is started under substantially no load.

It is another object of this invention to provide a directional control valve and switch arrangement as aforesaid in which the switch is adjustably mounted on a fixed part of the directional control valve housing so that initially the contact elements of the switch are in Off posit-ion when the movable valve element of the directional control valve is in neutral position.

It is another object of this invention to provide a motor starting switch of the character indicated which has its movable cont actor and contacts enclosed therewithin and thus protected from fouling and arcing by foreign matter as may be encountered, for example, in conjunction with fluid systems employed in fork lift trucks and like material handling equipment.

It is another object of this invention to provide an electric switch of the character indicated which is provided with a transparent cover which provides a clear view of the contacts and contactor therewithin, thus to facilitate adjustable mounting of the switch on a directional control valve.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative, however, of but one of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a cross-section view of a typical spool-type directional control valve having a pump motor energizing switch connected thereto for engagement of the switch plunger by the valve spool, the remaining elements of the fluid and electrical system, namely, the tank, the fluid motor, the pump, the pump drive motor, the motor starting relay, and the power transformer, being shown schematically;

FIG. 2 is a cross-section view taken substantially along the line 2-2, FIG. 1; and

ice

FIG. 3 is a cross-section view taken substantially along the line 33, FIG. 1.

Referring now more particularly to the drawing, and first to FIG. 1, the fluid system herein comprises a directional control valve 1, a pump 2, a double acting fluid motor 3 and a tank 4.

Insofar as the directional control valve is concerned, it may be of the spool type, as shown, the housing 5 thereof having a bore 6 therethrough which, starting at the middle, is intersected by a bypass passage 7 which leads to the tank port 8; by a pair of bypass branch passages 9; 9 straddling the .bypass passage 7 and communicating with the inlet port 10; by a pair of pressure feed passages 11; 11 also leading to the inlet port 10 and communicating with the aforesaid bypass branches 9; 9 by a pair of motor passages 12; 12 adapted to be communicated via conduits 14; 14 with the ports of the fluid motor 3; and by a pair of return passages 15; 15 which lead to the tank port 8. The directional control valve 1 will preferably have therein a pressure relief valve 16 which opens communication between the inlet port 10 and one return passage 15 in the event that the fluid pressure in said inlet port 10 builds up to a value exceeding that for which the relief valve 16 is set. Conduits 17, 18, and 19 respectively communicate the discharge port of pump 2 with inlet port Ill, the intake port of pump 2 with tank 4, and the tank port 8 with tank 4.

Reciprocable in said bore 6 is the valve spool 20 which has alternate lands and grooves and is yieldably held in the neutral position as shown by the centering spring mechanism 21 contained within the cap 23 which is screwed onto said housing 5.

When the spool 20 is in neutral position the inlet port 10 and tank port 8 are in fluid communication with each other through the aforesaid bypass branch passages 9; 9 and bypass passage 7, and communication between the respective feed passages 11; 11 and motor port passages 12; 12 blocked.

When the spool 20 is shifted to the right, as viewed in FIG.. 1, the pump drive motor 25 is started (-as hereinafter explained) during the initial portion of the movement of the spool 20, the fluid delivered by the pump 2 being freely circulate-d back to the tank 4 through the aforesaid bypass passages 9 and 7, whereby the motor 25 is started under substantially no load. As the spool 20 approaches its normal operating position, spool land 26 closes communication between one bypass branch 9 and bypass passage 7 and the metering section 27 of land 28 gradually closes communication between the other bypass branch 9 and bypass passage 7. Also, communication is gradually opened between the left feed passage 11 and leftmotor passage 12 by the metering section 29 of land 23 so that fluid under pressure will be delivered to the head end of the fluid motor 3 via the conduit 14 and the fluid displaced from the rod end of the motor 3 will flow through the conduit 14 to the right motor passage 12 to the adjacent return passage 15. When the manual force on the left end of spool 20 is released, the spring 30 will, through the follower 31., return the spool 20 to its neutral posit-ion at which time the switch 32 opens to deenergize the pump drive motor 25.

When the spool 20 is shifted to the left from its neutral position, the switch 32 will again close to energize the motor 25 before the aforesaid bypass 97 is closed and continued movement of the spool toward the left will open communication between the right feed passage 11 and right motor passage 12 to conduct fluid under pressure through the conduit 14 into the rod end of the fluid mot-or 3 and the fluid displaced from the head end of the motor 3 will flow through the conduit 14 and through the left motor passage 12 to the adjacent return a: passage 15. The right land 28 with its

metering sections

27 and 29 operate as previously described to provide for gradual cut-ofi and cut-in of the bypass and pressure circuits. As previously described, when force on the spool 20 is released, the spring 30 will, through the follower 34, return the spool to its neutral position again opening the switch 32 for deenergizing the pump drive motor 25.

Referring now in detail to the switch 32, it comprises a plastic body 40 having a fixed jaw 41 and a movable jaw 42 by which it is securely and adjustably clamped on the cylindrical end portion 43 of the cap 23, clamping being effected by tightening the screws 45 which draw the movable jaw 42 toward the fixed jaw.

Secured in the body 40 as by means of the respective pairs of

screws

46 and 47 are two pairs of spaced

contact elements

48 and 49 of which the elements 49 have integral external terminals 50. Terminal elements 57 are secured by the screws 46 to elements 48. Reciprocable in the body 40 is a switch plunger 52 which is urged by the springs 53 toward the left so that the plunger head 54 presses the contactor 56 against the left set of contacts 48 to establish a circuit through the coil 57 of the relay contactor 58 for the motor 25. When the plunger 52 is moved to the right, the spring 59 urges the contactor 56 against the right set of contacts 49 as the head 54 of the the plunger continues to move to the right hereafter, the coil 57 again being energized to start the motor 25 as aforesaid.

To seal the interior of the switch body 40, a packing ring 60 therein has a sliding seal around plunger 52 and preferably the internal hex size in the cap 23 is smaller than the outside diameter of the packing ring 60 so that the latter cannot inadvertently drop out.

Mounted on the body 40 as by means of the screws 61, is a transparent cover plate 62 which has laterally extending ribs adjacent its periphery which overlap portions of the body 40 and terminals 50 so as to close the interior of the body 40 from foreign matter. The transparent cover 62 is also useful in adjustably mounting the switch 32 on the directional control valve 1 since all that it is necessary to do is to place the socket or recess 63 defined by the fixed jaw 41 and the movable jaw 42 over the reduced end portion 43 of the cap 23, then move the switch 32 to the left as viewed in FIG. 1, until the contactor 56 is mid way between the pairs of

contacts

48 and 49. With the switch 32 in that position, the screws 45 will be tightened to draw the movable jaw 42 toward the fixed jaw 41 and thus securely clamp the switch 32 on the directional control valve 1. By way of example, the directional control valve spool 20 may have .22 travel in opposite directions from the neutral position to its respective operating positions, whereas the space between the contactor 56 and the respective sets of

contacts

48 and 49 is only, say, .040", whereby the switch 32 will be closed to energize the motor 25 after only .040 movement of the spool 21 in either direction, whereby the motor 25 starts the pump 2 without substantial back pressure since the bypass passages 9 and 7 will yet be substantially fully open. Continued movement of the spool 20 the remainder of its stroke will then progressively cut off the bypass and open up communication between the selected adjacent pressure feed and motor passages 11 and 12.

In FIG. 1 the power line for operating the motor is designated as L1, L2 and the switch 32 and relay coil 57 are preferably in the low voltage circuit of transformer 64. Of course, when the circuit of the relay coil 57 is closed, the relay contactor 58 will .be actuated thereby to close the motor 25 circuit to drive the pump 2.

It is to be understood that the present invention may be employed in systems wherein two or more directional control valves are employed for controlling the actuation of a corresponding number of fluid motors, and each spool may have associated therewith a switch 32 of the character herein described so as .to start the pump drive motor whenever any one of the spools is actuated. As evident, the nested springs 53 apply greater force on the plunger 52 than does the contactor spring 59 and, likewise, when the switch 32 is in its Ofi position as shown, the net spring force on the switch plunger 52 will be less than the force of the centering spring 30 holding the spool 20 in its neutral position.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. In combination, a directional control valve comprising a housing having an inlet port for connection with a pump, a tank port for connection with a tank, and at least one motor port for connection with a fluid motor, said housing also having a bore therethrough intersected axially therealong by a bypass passage from said inlet port to said tank port, and a pressure feed passage from said inlet port to said motor port; a valve spool movable axially in said bore from an inactive spring ield position whereat said inlet and tank ports are in fluid communication via said bypass passage and communication between said inlet and motor ports via said feed passage is blocked by said spool, to an operating position whereat said spool closes said bypass passage and fluid communication is established thereby between said inlet and motor ports via said feed passage whereby said fluid motor is actuated by fluid under pressure in said inlet port conducted to the motor through said motor port; and electric switch means for energizing an electric drive motor for said pump; said switch means comprising a body secured to said housing, a switch plunger means disposed adjacent an end of said spool, a cont-actor means, means mounting said contactor means for movement relative to said switch plunger means, said contactor means being in open circuit position when said spool is in said inactive position, means mounting said switch plunger means for movement in response to the initial portion of the movement of said spool from inactive position toward operating position, and means mounting said contactor means for movement to closed circuit position in response to such movement of said switch plunger means, said bypass passage being open during such initial portion of the movement of said spool whereby the electric drive motor is started while the pump is under substantially no load.

2. In combination, a control valve comprising a hous ing having a valve spool movable axially therein from an inactive position to at least one operating position; a tubular member secured to said housing around an end of said spool; and spring means in said tubular member engaged with said spool yieldably to hold the latter in inactive position; and electric switch means comprising a switch body including clamp means securing said body on said tubular member; switch plunger means disposed adjacent said end of said spool; spring means urging said plunger means against said end of said spool; a contactor on said plunger means; and a contact in said body engaged by said contactor upon movement of said spool from inactive position.

3. The combination of claim 2 further comprising means mounting said plunger means for movement with respect to said contactor to permit continued movement of said plunger means and spool following engagement of said contactor with said contact when said spool is moved in the direction of said plunger means.

4. The combination of claim 2 wherein means are provided for arresting movement of said plunger means upon engagement of said contactor with said contact during movement of said spool in the direction away from said plunger means, whereby movement of said spool to operating position may be continued.

5. The combination of claim 2 wherein said valve spool isaxially movable from an inactive position to either of two operating positions, and there are spaced apart contacts in said body straddling said contactor and alternately contacted by the latter upon movement of said spool toward one or the other operating positions, and there are means mounting said plunger means for movement with respect to said contactor to permit continued movement of said plunger means and spool when said spool is moved in the direction of said plunger means following engagement of said contactor with one of said spaced apart contacts, and means are provided for arresting movement of said plunger means in the opposite direction upon engagement of said contactor with the other one of said spaced apart contacts for continued movement of said spool away from said plunger means.

6. In combination, a control valve comprising a housing having a valve spool movable axially therein from an inactive position to at least one operating position; a tubular member secured to said housing around an end of said spool; and spring means in said tubular member engaged with said spool yieldably to hold the latter in inactive position; and electric switch means comprising a switch body including clamp means securing said body on said tubular member; switch plunger means disposed adjacent said end of said spool; spring means urging said plunger means against said end of said spool; a contactor on said plunger means; a contact in said body engaged by said contactor upon movement of said spool from inactive position; and means for adjustably clamping said body on said tubular member to vary the space between said contactor and contact when said spool is in inactive position.

7. The combination of claim 6 wherein said body has a transparent cover which encloses said contactor and contact in said body and through which said contactor and contact are visible to facilitate adjustable clamping of said body on said tubular member.

8. In combination, a spool type control valve and an electric switch for use with said control valve, said electric switch comprising a switch body having fixed and movable jaw means defining a socket for clamping on a tubular member around one end of said valve spool; a movable switch plunger means in said body extending axially from the bottom of said socket for abutting engagement with said one end of said spool; a contactor means on said plunger means; and a contact in said body, said contactor means being operative to engage said contact upon movement of said plunger means in one direction as a consequence of movement of said spool.

9. The combination of claim 8 wherein there is a pair of spaced apart contacts in said body straddling said contactor means, and means is provided for causing said contactor means alternately to enagage said contacts upon movement of said plunger means in opposite directions as a consequence of movement of said spool in opposite directions.

10. The combination of claim 9 wherein said body has a transparent cover means enclosing said contactor means and contacts in said body and through which said contactor means and contacts are visible for facilitating clamping of said switch with said contactor means spaced between said contacts.

References Cited by the Examiner UNITED STATES PATENTS 1,711,565 5/1929 Hatfield et al 103-25 X 2,323,519 7/1943 Dean.

2,331,109 10/1943 De Ganahl 20061.86 X 2,399,033 4/1946 Hudson ZOO-61.86 2,609,665 9/1952 Rappl -60 2,718,240 9/1955 Margrave.

3,104,529 9/1963 Goss 6053 JULIUS E. WEST, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,228,193 January 11, 1966 Herbert H. Schmiel et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant, lines 1 and 2, for "Herbert H. Schmiel, of Willoughby, Ohio, and Louis G. Hajma, of Warrensville Heights, Ohio," read Herbert H. Schmiel, of Willoughby, Ohio, and Louis G. Ha'jma, of Warrensville Heights, Ohio, assignors to Parker-Hannifin Corporation, of Cleveland, Ohio,

a corporation of Ohio, line 12, for "Herbert H. Schmiel and Louis G. Hajma, their heirs" read ParkerHannifin Corporation, its successors in the heading to the printed specification, lines 4 to 6, for "Herbert H. Schmiel, Trailard Drive, Willoughby, Ohio, and Louis G. Hajma, 24800 Emery Road, Warrensville Heights, Ohio" read Herbert H. Schmiel, Willoughby, Ohio, and Louis G. Hajma, Warrensville Heights, Ohio, assignors to Parker-Hannifin Corporation, Cleveland,

Ohio, a corporation of Ohio Signed and sealed this 16th day of August 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. IN COMBINATION, A DIRECTIONAL CONTROL VALVE COMPRISING A HOUSING HAVING AN INLET PORT FOR CONNECTION WITH A PUMP, A TANK PORT FOR CONNECTION WITH A TANK, AND AT LEAST ONE MOTOR PORT FOR CONNECTION WITH A FLUID MOTOR, SAID HOUSING ALSO HAVING A BORE THERETHROUGH INTERSECTED AXIALLY THEREALONG BY A BYPASS PASSAGE FROM SAID INLET PORT TO SAID TANK PORT, AND A PRESSURE FEED PASSAGE FROM SAID INLET PORT TO SAID MOTOR PORT; A VALVE SPOOL MOVABLE AXIALLY IN SAID BORE FROM AN INACTIVE SPRING-HELD POSITION WHEREAT SAID INLET AND TANK PORTS ARE IN FLUID COMMUNICATION VIA SAID BYPASS PASSAGE AND COMMUNICATION BETWEEN SAID INLET AND MOTOR PORTS VIA SAID FEED PASSAGE IS BLOCKED BY SAID SPOOL, TO AN OPERATING POSITION WHEREAT SAID SPOOL CLOSES SAID BYPASSS PASSAGE AND FLUID COMMUNICATION IS ESTABLISHED THEREBY BETWEEN SAID INLET AND MOTOR PORTS VIA SAID FEED PASSAGE WHEREBY SAID FLUID MOTOR IS ACTUATED BY FLUID UNDER PRESSURE IN SAID INLET PORT CONDUCTED TO THE MOTOR THROUGH SAID MOTOR PORT; AND ELECTRIC SWITCH MEANS FOR ENERGIZING AN ELECTRIC DRIVE MOTOR FOR SAID PUMP; SAID SWITCH MEANS COMPRISING A BODY SECURED TO SAID HOUSING, A SWITCH MEANS COMPRISING A BODY SECURED AND END OF SAID SPOOL, A CONTACTOR MEANS, MEANS MOUNTING SAID CONTACTOR MEANS FOR MOVEMENT RELATIVE TO SAID SWITCH PLUNGER MEANS, SAID CONTACTOR MEANS BEING IN OPEN CIRCUIT POSITION WHEN SAID SPOOL IS IN SAID INACTIVE POSTION, MEANS MOUNTING SAID SWITCH PLUNGER MEANS FOR MOVEMENT IN RESPONSE TO THE INITIAL PORTION OF THE MOVEMENT OF SAID SPOOL FROM INACTIVE POSITION TOWARD OPERATING POSITION, AND MEANS MOUNTING SAID CONTACTOR MEANS FOR MOVEMENT TO CLOSED CIRCUIT POSITION IN RESPONSE TO SUCH MOVEMENT OF SAID SWITCH PLUNGER MEANS, SAID BYPASS PASSAGE BEING OPEN DURING SUCH INITIAL PORTION OF THE MOVEMENT OF SAID SPOOL WHEREBY THE ELECTRIC DRIVE MOTOR IS STARTED WHILE THE PUMP IS UNDER SUBSTANTIALLY NO LOAD.