US1836813A - Hydraulic operating mechanism - Google Patents

Description

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Patented hec. 15, 1931 Y UNITED STATES PATENT OFFICE WILLIAM X. RANKIN; OF LANSDOWNE PENNSYLVANIA, ASSIGNOR T GENERAL IEEE()- TBIC COMPANY, A CORPORATION 0F NEW YORK HYDRAULIC OPERATING Application med September 11, 1929. Serial No. `391,963.

.My invention relates to hydraulic operating mechanism, and more particularly to operating mechanism for effecting operation of circuit breaker mechanism.

A principal object of my invention is the provision of hydraulic operating mechanism for effecting substantially uniform and -positive lnovement of a member, as a switch o erating member of the oil or fluid-break type, wherein. it is desirable that the switch contacts beactuated to closed position by a substantially constant force. A further object is the provision of pressure relief means whereby the force tending to move the switch member to,close d position is immediately diminished to an lnappreciable value upon the occurrence or existence of an abnormal circuit condition.

A further object is the provision of releas- -ing mechanism for concurrently tripping the switch operating member and decreasing the fiuid resistance to its opening movement.

A further object is the provision of switch operating mechanism which shall operate eficiently and smoothly, and which shall be immediately responsive to abnormal circuit conditions to permit opening movement of the switch.

My invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed'toand forming a part of this specification. f

Referring to the drawings, Fig. 1 is an elevational view, partly in section, of hydraulic operating mechanism; and Fig. 2 is a crosssectional View taken along the line 2 2 of Fig.- 1.

Referring to Fig. 1, a mainoperating member 1 is adapted'to be operatively connected to mechanism (not shown), as switch mechanism, for example, the mechanism being operated/'by recliprocatory movement of the member 1. Re iprocation of member 1 is effected by a fluid o'tor comprising a/piston 2 dispgosed'` within a iston cylinder or chamber 3, the piston being normally biased upon the shaft 10 by a spring or forms a top section of a fluid reservoir 9,

containing a non-compressible fluid 9a, as oil. The motor 6 when energized is adapted to rotate the shaft 10 which is vertically mounted with respect to the oil reservoir and impeller housing. A fluid impeller or pump 11, as of the centrifugal type, 4is disposed within the impeller housing and is mounted so as to be rotated thereby. A fluid-feed device 12 comprising a helical worm or screw, or equivalent structure, is likewise mounted upon shaft 10 in such a manner that energization of motor 6 tends to lift the liquid 9a from the reservoir into the impeller housing. The pitch of the helical worm, however, is such that the fluid may be forced upwardly through the casing 13 into the impeller housing onl when the speed of the motor 6 has been rought up to its normal or predetermined speed. As illustrated, casing 13 comprises a conduit extending appreciably beneath the normal level of the liquid in the reservoir and is open at its lower end, its upper end communieating .with the impeller 11. When the motor 6 is operated at comparatively low speeds, as when it is being brought up to speed, the liquid is not forced upwardly into the impeller housing, but runs out of the screw after a certain hydraulic head has been built up within casing 13,

As the speed of motor 6 increases, the hydraulic head within casing 13 becomes higher until there isa continual fluid feed from reservoir 9 to an impeller chamber 14 from whence it is forced by the impeller 11 through openings 14a (Fig. 2), into an outer passage 146 of the impeller housing communicating with passage 5 leading to the working end of cylinder 3. Accordingly, rotation of vmotor 6 at a predetermined speed isV effective to pump a substantially non-compressible liquid from the reservoir 9 to the impeller 11 which in turn forces it under pressure into the working end of cylinder 3 to actuate piston 2 and the coacting operating member 1.

Since it is generally desirable in switch mechanism that the member 1 be restrained in one of its limiting positions, and shall be released from such position in response to certain conditions, there. is provided means comprising a latch 15 normally biased by a spring 16 to engage a notch 17 in the member 1, when said member has been forced 4upwardly a predetermined distance to effect the -circit-closing operation, for example. The latch l5 is provided with a tail-like extension 17 adapted to cause. collapse of a switch-locking toggle 18 when the latch 15 Inoves into notch 17. A movable switch member 19 connected to toggle 18 and pivoted at 20, is adapted to be biased by a tension spring 21 in a` clockwise direction to break contact with a stationary contact 22 upon collapse of the toggle 18.. As illus.

trated, the switch member 19 controls the Y energization of motor 6 from the source 7,

the motor being deenergized by switch 19 when the member 1 has been actuated to its limiting position.

In the Voperation of switch mechanisms, as oil circuit breakers, for handling large power currents, vit is often undesirable to attempt closure of the switch if some abnormal condition, as a short circuit, continues to persist in the circuit to be closed. It is therefore necessary to provide means which will permit the Iswitch operating mechanism to be deenergized and to move towards open position before the switch mechanism has been actually closed, if such abnormal conditions still persist. For this purpose,there is provided means for immediately by-passing the source A of pressure acting on vthe piston 2, thereby permitting the spring 4 to return the member 1 to the position illustrated in Fig. 1. The means above described comprises a pressure relief valve 23 having guide anges 24 adapted for reciprocatory movement within the combined cylindrical guide and valve seat 25 disposed in the working end of the cylinv der 3. Valve 23 when open permits communication between the working end of cylinder 3 and a fluid compartment 26 in communication with, and forminga part of, the main reservoir 9 through an opening 27 in the lower part of partition 28.I Therefore, when valve 23 is open the fluid impelled through passage 5 is by-passed intothe reservoir with the result that there is no appreciable fluid pressure acting on piston 2, notwithstanding normal energization of the motor 6. The valve 23 is operatively connected to a lockby a weak or inadequate force.

ing and releasing toggle 29 adapted to be overtravelled, as illustrated, aga-inst a lug or stop member 30 secured to the reservoir casing. Toggle 29 is in turn operatively con nected through a link 3l to a pivoted member 32 adapted to be actuated by a crank and a reciprocatory rod 33 connected to a magnetizable 'core 34 of an electromagnet 35. The core 34 is provided with a member 36 against which al spring 37 bears to normally bias the magnetizable core to the position illustrated wherein the toggle is set in its overtravelled or locking position to maintain valve 23 in firm fluid-tight engagement with its seat. Accordingly, when valve 23 is closed the fluid pressure developed by impeller 12 tromagnet 40, Whose magnetizable core is operatively connected, as at 41, to the extension of latch 15, is connected in parallel with the electromagnet 35 so as to be actua-ted concurrently therewith. v

The operation is as follows:

With the elements in the position illustrated in Fig. 1 wherein the switch member 19 has been moved to engage contact 22 by manual or other suitable operating means, the cir.-

cuit of the motor 6 is completed to start rotation thereof. As the motor 6 is coming upto speed there will be no liquid supplied to the impeller 11 by the screw 12, thereby preventing the piston 2 from being actuated Words, the hydraulic head within casing 13 developed by the screw 12 when the motor is under speed is below the impeller casing, thereby preventing the impeller 11 from acting on other than air during its starting period. -As motor 6 reaches its normal or predetermined speed a steady flow of liquid is drawn into the impeller chamber whereupon the impeller 11 forces the liquid at full normal ssure through passage 5 into the working end of cylinder 3. Dueto the fact that the motor`6 is, adaptedto operate at substantially constant speed, the fluid `pres-- sure acting on piston 2 tending to raise the same, will be substantiallyv constant from the beginning to the end and its stroke thereby preventing erratic or uncertain operation of the main switch contacts. As the piston moves upwardly into circuit-closing position under the continued influence of the uid pressure developed by the impeller 11, the

notch 17 in the operating member finally In other moves into registry with the restraining portion of latch which is biased by the spring 16 into engagement with member 1 to prevent reverse movement of the same. The latch 15 engages at its opposite end the toggle` 18 at its mid point to cause it'to collapse and permit the spring 21 to open the switch member 19. The motor 6 is thereupon automatically deenergized when the operating stroke has been completed.

Let it now be-assumed that an overload or short circuitoccurs on the line which is to be controlled by the main switch mechanism. The current transformer 39 accordingly concurrently a'ctuates both of the electromagnets and 40. Actuation of electromagnet 35 serves to move the magnetizable core 35 against the tension of spring 37 to rotate the p1vot member 31 through the rod 33 in a clockwise direction, thereby causing collapse l appreciable resistance to the return 'move--v piston 2. The operating mechanism? of toggle 29 and opening of valve 23 so that the li uid in cylinder 3 may readily flow back into t e lower reservoir. Actuation of the electromagnet 40 serves to rotate the latch 15 in a clockwise direction to release the operating member 1 and permit the spring 4 to return piston 2 to its lowermost position. Due to the fact that valve 23 is now open the remaining fluid in cylinder 3 does not offer ment of is adapted for another circuit-closing movement only when the overload or other abnormal condition has cleared, thereby permitting closure of valve 23 by the spring 37.

If the mechanism is operated in the normal manner to eil'ect a circuit-closing operation but during this operation a short circuit, for example, should occur, the electromagnet 35 would be immediately actuated to open theI valve 22 and thereby by-pass the source of fluid pressure back to the main reservoir. The fluid pressure acting on the piston 2 would be correspondingly diminished to an inappreciable value so that the spring 4 would be effective to immediately return the piston to the open circuit position. In the event that the switch mechanism is closed and it is desired to trip it, switch 38 is thrown to connect the electromagnets across source 7 thereupon concurrently energizing and actuating them to open the mechanism in the same manner as in the case of a short circuit or overload. Upon manual operation of the mechanism, switch 38 is subsequently returned to its original position connecting the electromagnets with the current transformer 39 so that the closing operation may be initiated by movement of the switch member 19 to complete the motor circuit. The movement of switch member 19 to circuitclosing position likewise moves the toggle 18 to its overtravelled or locking position rfrom which it may be moved by the actuation of latch 15. l

Afluid pressure,

operated position,

upon attainment of a predetermined vbe It Vshallbe understood that various modications and changes may be made in the .operating mechanism as illustrated without departlng from the spirit of my invention; for example, the electromagnets 35 and 40 may be rrendered responsive to abnormal conditions other than overload or short circuit, such as low voltage,y current reversal, etc.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Hydraulic switch operating mechanism, comprising a source of lluid pressure, a

switch operating -member Iadapted to be moved to circuit-closing position by said means for directing fluid ressure to said switch member when a preY etermined norma-l pressure obtains thereby effect- .ing operation of said member at a constant pressure, and pressure relief means for decreasing sa1d pressure 1n response to an abnormal clrcuit condltlon, said member thereupon being permitted to move towards its' open circuit position. v

2. Hydraulic operating mechanism comprising a fluid impeller, a main operating member adapted to be actuated by fluid pressure developed by said impeller, means for engaging and restraining said member in its and pressure relief means associated -with the main operating member, said restraining means and pressure relief means adapted to be concurrently actuated to permit reverse movement of the operating rmember' in response to a predetermined condition of the apparatus controlled by said member.

prising a fluid impeller, a fluid reservoir associated therewlth, a Afluid-feed device oIperatively connected to the impeller for de 1vering fluid from the reservoir to the impeller thereof, 'a main operating member adapted to actuated at substantially constant pressure by the fluid discharged from said impeller, and means for by-passing the fluid acting on said operating member in response to a predetermined condition of the apparatus controlled thereby whereby said member is deenergized and permitted to return to its initial position.

4. Hydraulic operating mechanism comprising a motor-driven fluid impeller, a fluid reservoir, a fluid-feed device operable at a predetermined speed to deliver fluid from said reservoir to said impeller, a pressure actuated operating member associated with said impeller,/means for engaging and restraining said -member in its operated position,- and means cooperatin with the afore- -said .means for thereupon eenergizing said speed 3. Hydraulic .operating mechanism comoperating mechamsm comprising a uid impeller, a switch operating member adapted to be actuated by iuid pressure developed by said impeller, means for engaging and restraining said member in its closed position, and means cooperating with the aforesaid means for thereupon deenergizing said fluid impeller.

v6. In a switch operating system, hydraulic operating mechanism comprising a fluid impeller, a fluid reservoir, a fluid-feed device operatively connected to said impeller for delivering fluid from the reservoir to the impeller when it has attained a predetermined speed, a switch operating member actuated at substantially constant pressure by fluid discharged from the impeller, pressure relief means associated withI said member, and means responsive to an abnormal circuit condition for actuating said relief means for permitting movement of the switch operating member towards open position.

7. In a switching system, hydraulic operating mechanism foreffecting movement of a switch operating member to closed posltion comprising a fluid impeller, a piston associated with said operating member, means providing liuid communication between said impeller and the working side of said piston,

and a pressure relief valve for by-passmg the Huid acting on said piston in response to an abnormal circuit'vcondition. l

8. In a switching system, hydraulic operating means for effecting closing movement of a switch member comprising a iuid impeller, a piston connected to said member, means providing fluid communication between .said impeller and the working side of the piston, means for engaging and restraining said switch member in its closed position, re-

. silient means urging the member towards open position, and a pressure relief valve associated with the working side of the piston for diminishing the iuid Ypressure acting on the piston, said restraining means and relief valve adapted to be actuated in re'- sponse to an abnormal circuit condition, whereby the aforesaid resilient means is effective to return the switch member to its open position.

9. In a switching system, hydraulic operating means for effecting closing movement of a switch member comprising a fluid impeller, a fluid reservoir, a helical worm operatively connected to the impeller for delivering fluid ,from the rservoir -to the impeller when it-"has attained normal speed, means vproviding fluid communication between said impeller and switch member whereby said membermay be. actuated by constant fluid pressure, and/means eo-acting with said member for deeri'ergizing said impeller when the member has been 'noved into circuit-closing position.

' 1 10, Gircuit-clsing mechanism comprisn -`ing a switch Aoperating member, a piston and working end of' said cylinder, said valve normally biased towards closed position, and electro-responsive means associated with said valve for opening the same and deenergizing said piston in response to an* abnormal circuit condition.

11. Circuit-closing mechanism comprising a switch operating member, a piston and cylinderl associated therewith, a fluid impeller in fluid communication with the working end of the cylinder, a iuid reservoir, a fluidfeed device for delivering fluid from said reservoir to the impeller when said impeller has attained normal speed thereby 'effecting operation of said piston and switch operating member at substantially constant pressure, a pressure relief valve disposed at the working end of said cylinder and opening into said reservoir, latching means for engaging and restraining the switch'member in its circuit-closing position, resilient means for urging the switch member towards its open circuit position, and electromagnetic means operatively connected to said latching means and relief valve for concurrently actuating latching means in response to energization 4 ofthe same, and a pressure relief valve associated with the fluid motor for deenergizing the same when open, said valve adapted to be opened concurrently with actuation of said latching means whereby the switch opel-ating member is biased by said spring towards its open position.

13. Circuit-closingmechanism comprising a switch operating member, a fluid motor for actuating the same, a source of fluid pressure adapted to be operatively associated with saidmotor, a pressure relief valve disposed at the vworking end of the motor adapted when open to deenergize. the same, toggle structure for maintaining said valve in its closedposition, resilient means cooperating with said toggle structure for normally bias# ing said valve toward the closed position, an electromagnet lfor eii'ecting vcollapse of said toggle and movement of the valve to its open position i-n response to an abnormal circuit condition, and means normally urging the switch operating member towards open position upon deenergization of said motor.

14. Circuit-closing mechanism comprising a switch operating member, a piston and cylinder associated therewith, amotor-driven pump for supplying a liquid under pressure to said cylinder for actuating the piston and switch operating member, areservoir from which liquid is delivered by a Huid-feed device to the pump, said Huid-feed device operatively connected to said pump and adapted to deliver liquid thereto when the pump has attained its normal .speed whereby said member may be moved to its circuit-closing position at substantially constant pressure, latching means for restraining said member in said position, a pressure relief valve disposed at the working end of the cylinder, a spring tending to move the switch operating member to the open-circuit position upon the opening of the relief valve, electromagnetic means for effecting movement of the relief valve to its open position, and electroma netic means actuated concurrently with sald lirst-named electromagnetic means for releasing said latching means for permitting movement of the switch operating member to its open circuit position.

l5. The combination with a switch operating member, of hydraulic mechanism for actuating said member comprising a piston and coactin cylinder, a fluid pump in operative connection with the working end of said cylinder, means for permitting the pump to attain normal s eed before fluid is delivered thereto whereby fluid may be delivered'to said cylinder at substantially constant pressure, means for restraining the switch operating member in its circuit-closing position, pressure relief means disposed in the working end of said cylinder, and means responsive to an abnormal circuit condition for actuating both the restraining and pressure re- `lief means, thereby permitting movement of the switch operating member to the open circuit position. i

In witness whereof I have hereunto set my hand this 7th da of Se tember, 1929.

LL M K. RANKIN.

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