US3806679A

US3806679A - Actuator for pole-mounted switches

Info

Publication number: US3806679A
Application number: US00341530A
Authority: US
Inventors: J Pahl
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-03-15
Filing date: 1973-03-15
Publication date: 1974-04-23
Anticipated expiration: 1991-04-23

Abstract

A housing secured to a power pole encloses a hydraulic ram movable between two extreme positions An exterior vertically translatable operating rod is connected at its lower end to the ram and extends upwardly to a gang of high voltage electrical switches mounted on the pole. The rod moves upwardly and downwardly in response to ram movement. In turn, translation of the operating rod between the two extreme positions actuates the high voltage switches between open and closed positions. Movement of the ram is substantially instantaneously effected by a high pressure accumulator acting through valving which is controlled either locally or remotely by appropriate electrical circuitry. A hydraulic pump and motor within the housing are regulated by high and low pressure switches and serve to maintain the fluid pressure in the accumulator within a predetermined optimum range. Remote control of the actuator is afforded by radio, telephone or wire.

Description

EJYI'E HED 2 1914 7 SHEET 2 OF 2 w W M .OIO

o6 w v 4 OIOI 5( T I mmwmww Z W w M A 22 1 1 6 Dev G ow r 0 x6 P fiu vw w y .9 o w 4 3 2 2 W. & 3V3 5 Jig k E n W i Pf)? I ACTUATOR FOR POLE-MOUNTED SWITCHES BACKGROUND OF THE INVENTION The prior art affords numerous disclosures relating to electromechanical devices for opening and closing gangs of high voltage electrical switches, exemplary being T. F. Johnson US. Pat. No. 3,026,388 and No. 3,189,698, wherein an electric motor rotates a vertical operating shaft to actuate a gang of switches.

The amount of torque afforded by installations of the customary electric motor-drive type is inherently limited, thereby creating possible difficulties under severe icing conditions, for example. Comparable problems can sometimes exist in actuators of the linear thrust, or translatable, type; and in either case there is room for improvement in switch actuators, especially of the remotely controlled variety, where reliability of operation is imperative under widely ranging conditions of weather and adverse circumstances including temporary power failure.

SUMMARY OF THE INVENTION I The invention relates generally to improvements in switch actuators, particularly, to switch actuators including translatable operating rods which are moved, on command, by a remotely controlled high pressure accumulator.

It is an object of the invention to provide a switch actuator which is self-contained and fully operable for as may a 18 Prat 9t sy2 h n q ttis P w failure occurs, thereby affording standby reliability under emergency conditions.

It is another object of the invention to provide a switch actuator which although lending itself particularly well to pole line installations, can also be used to advantage in underground applications.

It is yet another object of the invention to provide a switch actuator which is relatively economical and compact in size, yet is sturdy, long-livedand reliable under a wide range of temperature, humidity and other contitions.

It is a further object of the invention to provide a switch actuator which has but few moving parts to get out of order and which can readily be repaired if necessary. l

It is another object of the invention to provide a generally improved switch actuator.

Other objects, together with the foregoing, are attained in the embodiment described in the following description and shown in the accompanying drawings, in which: I

FIG. 1 is a front elevational view of a typical layout within a protective housing, the housing cover being shownin fully open position and broken away to re duce the extent of the figure;

FIG. 2 is a fragmentary side elevational view of the operating rod connection, the rod and the lever being shown in lowermost position;

FIG. 3 is a circuit diagram; and,

FIG. 4 is a schematic diagram of the hydraulic system.

While the switch actuator of the invention is susceptible of numerous different physical embodiments, depending upon the environment and requirements of use, substantial numbers of the herein shown and described embodiment have been made, tested and used,

and all have performed in manner.

The actuator of the invention, generally designated by the reference numeral 12, is located within a sturdy, box-like metal housing 13 including a back wall 14, opposite side walls 15, atop wall 16 and a bottom wall 17. A cover 18 is customarily hinged on the edge of the left side wall and, when closed, protects the enclosed structure. The cover is locked in closed position to preclude tampering.

The box 13 is ordinarily mounted on a power pole 19 at a convenient height near the bottom of the pole. A gang of high voltage switches, not shown, is mounted adjacent the top of the pole and connected to a respective array of conductors in customary fashion. Each of the switches is capable of being turned on and off so as to afford continuity to the respective conductor or to open the conductor by interrupting it, in well-known manner. Actuators are frequently either of thepivoted blade type, as shown in the above-identified Johnson patents, or of the translatable variety, which is used in conjunction with the present actuator.

In order to translate the switch blade, not shown, upwardly and downwardly, on command, so as to turn the switch on or off, there is provided a vertical operating rod 21 pivotally connected at its upper end to the switch blade and at its lower end to a pitman 22 con nected to the distal end of crank arm 23. The crank arm 23 is mounted on a shaft 24 extending into the box and being journaled in a bearing 26 on the rear wall 14. In order to actuate the shaft 24 and the crank arm 23 so as to translate the pitman 22 and the operating rod 21 upwardly or downwardly, on command, the end of the shaft 24 which is within the box is fastened to a lever 28, the lever 28 being forked and pivotally mounted on the lower end of a piston rod 29 of a hydraulically actuated ram 31.

The forked end of the lever 28 includes a slot 32 within which is lodged the pivot pin 33 of the piston rod, thereby accommodating for the radial swing when the piston rod moves between a first retracted position as shown in full line in FIG. 1 and a second projected position indicated in broken line in FIG. 1. The doubleacting ram 31. is actuated by a hydraulic system 36 including a first pipe 37 extending from a conventional four-way valve 38 to the lower, or piston, end 39 of the hydraulic cylinder 40, and a second pipe 42 extending from the four-way valve 38 to the upper end 41 of the cylinder 40. A pump 43 driven by an electrical motor 44 communicates through pipe 45 with a hydraulic fluid reservoir 46, or tank; and as pumping takes place, pressurized fluid emerging from the pump 43 is routed through a check valve ,47to a high pressure accumulator 48 in which the fluid pressure is on the order of 2,000 p.s.i. with a capacity enabling the system to actuate the gauged switches up to 18 times in the event power failure occurs.

From the accumulator 48 a pipe 49 extends to the four-way valve 38 which controls high pressure fluid flow to the appropriate end of the cylinder 40 and which also routes the fluid emergent from the cylinder back through a pipe 51 to the storage tank 46.

A Barksdale pressure switch, generally designated by the reference numeral 53, affords three separately acting switches, a low-pressure switch 54, a highpressure switch 56 and a cutoff switch 57, as will subsequently be explained in detail. The pressure switch 53 an eminently satisfactory is in communication with the accumulator; and the

individual switches

54, 56 and 57 sense the fluid pressure within the accumulator. Each of the three switches can be set to a predetermined pressure so that the switches turn off or on in dependence upon whether the accumulator pressure is more or less than the set pressure of the respective switch, as will be explained. The switch 53 senses the accumulator pressure by means of a connecting pipe 58 extending between the accumulator 48 and the switch 53.

The four-way valve 38 is of the conventional doubleacting, solenoid-actuated type with an interposed spindle which shuttles in response to the forces exerted thereon by the solenoids. A spindle-centering spring is not used. Thus, when the spindle moves toward either end of the valve chamber, the spindle remains at the end until the operator reverses the spindle position. In other words, the actuator is locked" either in fully on or fully of position at all times during operation, thereby affording an important safety feature.

In either of the two extreme positions of the piston rod 29 and the associated lever 28, corresponding to fully on or fully off position of the line switches, one or the other of a pair of

limit switches

61 and 62 is physically contacted and urged into closed circuit condition. Thus, as appears in full line in FIG. 1, and as can be seen by reference to the wiring diagram in FIG. 3, with the lever 28 in up position, the upper limit switch 61 is closed. Concurrently, the lower limit switch 62 is open.

With the upper limit switch 61 closed and the lower limit switch 62 open, the left-hand portion 63 of the 12- volt direct current circuit (see FIG. 3) is in closed circuit condition, ready to be energized as soon as the switch open button 65 is pressed. The switch open button 65 can be located at a remote station, if desired, being connected to the 12 volt circuit 64 by a first conductor 66 and a second conductor 67 forming a common bus leading to the grounded terminal 68 ofa 12 volt battery 69, whose charge is maintained by a conventional battery charger 71 connected to a suitable 120 VAC power source 72.

It is to be noted, at this juncture, that while the embodiment disclosed herein affords remote control by a connecting three-wire arrangement, control can also be effected by operating signals which orginate at a remote station and are transmitted to the actuator by telephone, radio or other suitable source of electromagnetic radiant energy.

The l VAC power source 72 is connected through a pair of conductors 73 and 74 attached to respective wires 76 and 77 leading to the battery charger 71 and also to

respective terminals

78 and 79 of a terminal board 81.

As previously indicated, with' the limit switch 61 in closed position, corresponding to the condition shown in full line in FIG. 1 with the piston in retracted position (and arbitrarily assuming that the ganged switches are in closed condition also), pressing the switch open" button 65 will energize the open windings 82 in the solenoid-operated four-way valve 38, causing the valve 38 to route high-pressure hydraulic fluid from the accumulator 48 through the pipe 42 to the upper end 41 of the arm 31, thereby ejecting the piston 29 substantially instantaneously and moving the lever 28 and attendant lever 23 and actuating rod 21 from the upper position shown in full line in FIG. 1 to the lower position shown in full line in FIG. 2'and in fragmentary broken line in FIG. 1.

The operating rod 21, in so translating, opens the gang of actuating switches located high above on the pole. The ganged switches, furthermore, are positively and with great force maintained in open position since the shuttle within the valve is not self-centering under the influence of centering springs, or the like, as ex plained above. By thus remaining in fully displaced position, the solenoid-actuated spindle within the fourway valve continues to bring full accumulator pressure to bear on the upper end of the piston 29.

Release and reversal of the piston 29 can be effected, however, by pressing the switch close button 84. The ht as? ti afiqf tbs 2 Circuit isa y closed since when the piston 29 moved downwardly to switch open position, the lever 28 physically contacted and closed the lower limit switch 62.

It will be noted, incidentally, that in moving from upper to lower position, the lever 28 released the upper limit switch 61, allowing the upper limit switch 61 to open and therby placing the left-hand portion 63 of the 12V circuit in open-circuit condition.

As stated above, pressing the switch close button 84 will complete the right-hand portion 86 of the 12V circuitjcu rr ent flow being from the battery 69 through the normally closed low pressure cutoff switch 57, through the close windings 87 and the now closed lower limit switch 62, thence through a wire 88 to the button 84, from which point current flow is through the return common bus 67 to ground.

Upon being energized, the close windings 87 reverse the position of the flow controlling spindle within the four-way valve substantially instantaneously, with a corresponding instantaneous rerouting of high pressure fluid from the accumulator 48 through the pipe 37 leading to the lower end 39 of the cylinder 40. Exhaust from the upper end 41 is simultaneously led through pipe 51 to the fluid storage tank 46. At the same the upward movement of the piston 29, the lever 28 and the attendant exterior lever 23, pitman 22 and operating rod 21 takes place. The ganged switches are thereby closed and held securely in closed position, for the reason previously explained.

Concurrently with the upward movement of the lever 28, the lower limit switch 62 opens and the upper limit switch 61 is closed, thereby completing the cycle and restoring the l2V circuit 64 to its initial condition, with the left-hand side 63 of the 12V circuit closed, and ready to be energized, while the right-hand side 86 of the 12V circuit is in open circuit condition.

The extremely high pressure accumulator 48 possesses sufficient volume so that numerous energy withdrawals can be made without replenishment.

Provision is made, however, for automatically restoring the accumulator pressure to full charge when the fluid pressure drops to the lower end of a predetermined optimum range of pressures to be maintained in the accumulator.

With particular reference to FIG. 3, it can be seen that a pair of conductors and 89 connected to the VAC source 72 through

respective terminals

78 and 79 on the terminal board 81 provides power to operate, on command, the accumulator recharging unit, generally designated by the reference numeral 90.

From the

conductors

85 and 89,

respective wires

91 and 92 extend to the motor 44 which drives the hydraulic pump 43 and thereby re-pressurizes the accumulator 48, when required. A switch 93 is opened and closed-by an actuator 94 controlled, in turn, by a conventional Honeywell controller 95. The actuator 94 is functionally a part of the controller 95.

The controller 95 is interposed in the 120 VAC line 85, and shunting the controller 95 to the other 120 VAC conductor 89 is a first low pressure shunt circuit 96, extending from the conductor 89 through the low pressure switch 54, thence to the controller 95, and a second high pressure shunt circuit 97 extending from the conductor 89 throughthe high pressure switch 56, thence through the actuator 94 and to the controller 95.

When the fluid pressure within the accumulator 48 drops below a predetermined lower pressure, the normally open low pressure transducer switch 54 senses the occurrence and closes the low pressure circuit 96, thereby energizing the coil within controller 95 and simultaneously closing the motor switch 93 and closing the internal contacts in the actuator 94. g

The energized motor 44 drives the pump 43 which thereupon withdraws fluid from the reservoir 46 through the pipe 45 and routes it through the check valve 47 to build up the pressure in the accumulator 48.

When the internal contacts within the actuator 94 are thus closed by the controller, the high pressure switch 56, which closes after the pressure falls below a predetermined upper amount, completes thecircuit 97, both to run and pressure continues to build up in the accumulator.

After the pressure has built up to a predetermined amount set. in the low pressure switch 54, the switch 54 opens, thereby opening the low pressure circuit 96. However, the high pressure circuit 97 remains closed, thereby continuing to energize the controller 95 and the motor 44 while the contacts of the actuator 94 continue to remain closed.

As the fluid pressure within the accumulator reaches the established upper limit, the high pressure transducer (switch) 56 opens, thereby interrupting the high pressure circuit 97.

Then, since both the low pressure shunt circuit 96 and the high pressure shunt circuit 97 are open, the coil of thecontroller 95 is no longer energized, with the result that the motor switch 93 is opened, causing the motor to stop, and the internal contacts in the actuator 94 are likewise opened.

At this juncture, the accumulator 48 is fully recharged and the automatic pressurizing cycle is complete, and both the low pressure switch 54 and the high pressure switch 56 are open. After the fluid pressure drops somewhat, the high pressure switch 56 again closes, at a pre-set amount. However, closure of the high pressure, switch 56 does not close the high pressure circuit 97 since the contacts within the actuator 94 are still open. Only when the low pressure switch 54 circuits being thereby closed while the motor continues I operation. When the switch 57 opens, the conductor 98 between the battery 69 andthe terminal 99 branching to the solenoid coils 82 and 87 is opened and the fourway valve 38 is unable to operate until accumulator pressure is restored.

It can therefore be seen that l have provided an actuator for pole-mounted switches which is rugged and efficient under a wide range of environmental conditions, but which also possesses a number of important safety features.

What is claimed is:

1. An actuator for a pole-mounted switch comprising:

a. a housing secured to a pole having an electrical switch mounted thereon, the switch being of the type which is opened and closed by alternate reciprocation of an operating rod;

b. a hydraulic ram mounted on said housing, said ram including a piston movable between a first retracted position and a second projected position;

0. a lever connecting said piston and the operating rod for on-off actuation of the switch in dependence upon the movement of said piston;

d. a hydraulic pressure accumulator mounted on said housing capable of substantially instantaneously operating said hydraulic ram on command;

e. valve means connected to said ram and to said accumulator for controlling the flow of hydraulic fluid to said ram; and,

f. means connected to said valve means for directing the movement of said valve means and thereby controlling the movement of said piston between said first position and said second position to effect corresponding movement of the operating rod and actuation of the switch.

2. An actuator as in claim 1 including means in said housing for maintaining the hydraulic fluid pressure in said accumulator within a predetermined pressure range.

3. An actuator as in claim 2 wherein said pressure maintaining means includes: an electrical motor-driven hydraulic pump, a fluid tank and associated piping interconnecting said valve means, said accumulator and said ram; an electrical controller connected to said motor, said controller being capable of turning said motor on or off on command; a low pressure switch electrically connected to said controller and mechanically connected to said accumulator for sensing the hydraulic fluid pressure within said accumulator, said low pressure switch being capable of actuating said controller and turning on said motor when the pressure within said accumulator falls to a predetermined lower limit amount; and a'high pressure switchelectrically con nected to said controller and mechanically connected to said accumulator for sensing the hydraulic fluid pressure witin said accumulator, said high pressure switch being capable of actuating said controller and turning off said motor when the pressure within said accumulator rises to a predetermined upper limit amount.

4. An actuator as in claim 3 further including limit switch means operable in response to the movement of said piston between said first position and said second position.

5. An actuator as in claim 4 in which said valve means includes a four-way valve; and a solenoid-type valve actuator connected to said four-way valve.

6. An actuator as in claim further including a 12 volt direct current circuit comprising a 12 volt battery; a battery charger connected to said battery and to a 120 volt alternating current power source; and wherein said limit switch means includes a first limit switch connected to said battery and to said solenoid-type valve actuator in a manner such that when said first limit switch is mechanically closed by contact with said piston, said valve actuator routes the flow of fluid from said accumulator to said ram in a direction such as to move said piston from said first retracted position toward said second projected position, and a second limit switch connected to said battery and to said solenoid-type valve actuator in a manner such that when said second limit switch is mechanically closed by contact with said piston, said valve actuator routes the flow of fluid from said accumulator to said ram in a direction such as to move said piston from said second projected position toward said first projected position.

7. An actuator as in cliarn 6 in which said 12 volt battery circuit also includes a low pressure cutofi switch interposed between said battery and said first limit switch and said second limit switch, said cutoff switch being mechanically connected to said accumulator and being capable of deactivating said solehoid-type valve actuator to preclude the operation of said ram when the fluid pressure within said accumulator is below a predetermined amount.

8. An actuator as in claim 1 in which said valve directing means is connected to a remote control station by electrical conductors.

- 9. An actuator as in claim 1 including a transducer connected to said valve directing means, said transducer being responsive to controlled electro-magnetic radiant energy emanating from a remote control station and being thereby capable ofcontrolling the flow of hydraulic fluid to said ram and effecting corresponding actuation of the pole-mounted switch.

Claims

1. An actuator for a pole-mounted switch comprising: a. a housing secured to a pole having an electrical switch mounted thereon, the switch being of the type which is opened and closed by alternate reciprocation of an operating rod; b. a hydraulic ram mounted on said housing, said ram including a piston movable between a first retracted position and a second projected position; c. a lever connecting said piston and the operating rod for onoff actuation of the switch in dependence upon the movement of said piston; d. a hydraulic pressure accumulator mounted on said housing capable of substantially instantaneously operating said hydraulic ram on command; e. valve means connected to said ram and to said accumulator for controlling the flow of hydraulic fluid to said ram; and, f. means connected to said valve means for directing the movement of said valve means and thereby controlling the movement of said piston between said first position and said second position to effect corresponding movement of the operating rod and actuation of the switch.

3. An actuator as in claim 2 wherein said pressure maintaining means includes: an electrical motor-driven hydraulic pump, a fluid tank and associated piping interconnecting said valve means, said accumulator and said ram; an electrical controller connected to said motor, said controller being capable of turning said motor on or off on command; a low pressure switch electrically connected to said controller and mechanically connected to said accumulator for sensing the hydraulic fluid pressure within said accumulator, said low pressure switch being capable of actuating said controller and turning on said motor when the pressure within said accumulator falls to a predetermined lower limit amount; and a high pressure switch electrically connected to said controller and mechanically connected to said accumulator for sensing the hydraulic fluid pressure witin said accumulator, said high pressure switch being capable of actuating said controller and turning off said motor when the pressure within said accumulator rises to a predetermined upper limit amount.

6. An actuator as in claim 5 further including a 12 volt direct current circuit comprising a 12 volt battery; a battery charger connected to said battery and to a 120 volt alternating current power source; and wherein said limit switch means includes a first limit switch connected to said battery and to said solenoid-type valve actuator in a manner such that when said first limit switch is mechanically closed by contact with said piston, said valve actuator routes the flow of fluid from said accumulator to said ram in a direction such as to move said piston from said first retracted position toward said second projected position, and a second limit switch connected to said battery and to said solenoid-type valve actuator in a manner such that when said second limit switch is mechanically closed by contact with said piston, said valve actuator routes the flow of fluid from said accumulator to said ram in a direction such as to move said piston from said second projected position toward said first projected position.

7. An actuator as in cliam 6 in which said 12 volt battery circuit also includes a low pressure cutoff switch interposed between said battery and said first limit switch and said second limit switch, said cutoff switch being mechanically connected to said accumulator and being capable of deactivating said solenoid-type valve actuator to preclude the operation of said ram when the fluid pressure within said accumulator is below a predetermined amount.

9. An actuator as in claim 1 including a transducer connected to said valve directing means, said transducer being responsive to controlled electro-magnetic radiant energy emanating from a remote control station and being thereby capable of controlling the flow of hydraulic fluid to said ram and effecting corresponding actuation of the pole-mounted switch.