US3047694A - Load pickup switch latch mechanisms - Google Patents

Description

July 31, 1962 Filed July 12, 1957 J. D. SULLIVAN LOAD PICKUP SWITCH LATCH MECHANISMS Fig. I.

3 Sheets-Sheet l July 31, 1962 Filed July 12, 1957 J. D. SULLIVAN LOAD PICKUP SWITCH LATCH MECHANISMS 3 Sheets-Sheet 2 Fig. 2.

July 31, 1962 Filed July 12, 1957 J. D. SULLIVAN LOAD PICKUP SWITCH LATCH MECHANISMS 3 Sheets-Sheet 3 Fig. 5.

United States .Patent() 3,047,694 LOAD PICKUP SWITCH LATCH MECHANISMS Jimmie D. Sullivan, Baltimore, Md., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed July 12, 1957, Ser. No. 671,511 2 Claims. (Cl. 200-106) My invention relates generally to automatic sectionalizing switches, and it has reference in particular to an automatic sectionalizing switch for load pickup operations.

Generally stated, it is an object of my invention to provide a simple and inexpensive automatic sectionalizing and load pickup switch that is reliable and positive in operation.

More specifically, it is an object of my invention to provide in a sectionalizing switch having separable contacts which are normally latched closed, for more positively actuating the latch by a time delay device in response to loss of voltage.

Another object of my invention is to provide in a sectionalizing switch for improving the tripping operation by using an air dashpot device for releasing a stored energy device to actuate the switch operating mechanism a predetermined time after loss of voltage.

Yet another object of my invention is to provide in an automatic sectionalizing switch for actuating a latch to open the switch by means of a time delay device which is responsive to loss of voltage.

It is also an object of my invention to provide in connection with a switch, spring-biased latch tripping means in connection with an air dashpot time delay device for suddenly imparting an actuating force to release the latch and open the switch in response to a relatively weak operating force of the time delay device.

It is another important object of my invention to provide in an automatic sectionalizing switch for using an air dashpot delay device in conjunction with an impulse release mechanism and latched stored energy trip means, so as to prevent application of any tripping force to the switch latch until a sufiicient force is available to insure absolutely positive operation of the latch.

Yet another important object of my invention is to provide in an automatic sectionalizing switch for using a releasable latch mechanism which is actuated by a stored energy trip lever released by a dashpot time delay device remotely located from the switch latch, for mechanically releasing the latch upon loss of voltage, and for using a plug-in type thermal time delay device for delaying energization of a closing solenoid for the switch for a predetermined time after voltage is restored.

Other objects will, in part, be obvious and will, in part,

"ice

plug-in type which is mounted in the enclosure with the dashpot delay device.

For a complete understanding of the nature and scope of my invention, reference may be made to the following detailed description which may be read in connection with the accompanying drawings, in which:

FIGURE 1 is a reduced front elevational view of a switch embodying the invention in one of its forms;

FIG. 2 is an enlarged sectional view of the switch taken generally along the line II-II of FIG. 1;

FIG. 3 is an enlarged sectional view of the control en,- closure shown in FIG. 1;

FIG. 4 is a plan view, broken out in part, of the operating mechanism shown in FIG. 2;

FIG. 5 is a diagrammatic view of a distribution system illustrating an application of a switch embodying my invention;

FIG. 6 is a partial elevational view of the operating mechanism; and V v FIG. 7 is a side elevational view of part of the mechanism mounted on bracket 89 of FIG. 4.

Referring particularly to FIGS. 1 and 2, it will be seen that my invention may be embodied in a switch generally of the type disclosed in Patent No. 2,697,149, which issued to Jarnes M. Wallace and Alvin W. Oggon December 14, 1954, and more particularly of the type disclosed in application Serial No. 517,040 of L. V. Chabala, filed June 21, 1955 and now Patent No. 2,832,010. As therein disclosed, the switch 10 is enclosed within a metal tank 11 which is provided withan insulating liner 12 and is surmounted by a topcasting 14. An incoming line enters by means of conductors 17 which pass through bushings 15 and 16 mounted on the casting. Since the view shown in FIG. 2 is a central section, only the bushing 15 is shown with its conductor 17 which terminates in a stationary contact 18 at the lower end, it being realized that each of the bushings is pro vided with a similar contact. These contacts are bridged by a contact bar 20 which is slidably mounted on an insulating contact pull rod 21. The contact bar 20 is located beneath the upper leg 22 of a substantially 1 lever 28 is pivotally supported at another terminal point tially L-shaped frame 36 secured to the underside of the contacts which are operated by a toggle mechanism having a handle extension on one lever of the mechanism for manually operating the switch. A releasable latch is provided for releasing the toggle mechanism,vand this latch is actuated by a releasable stored energy trip lever.

An undervoltage device having an air dashpot for delayu casting 14 by means of bolts 38. Since the depending leg 35 of the frame 36 is located in front of the operating mechanism it has been broken away to show the operating mechanism more clearly and is thus shown in a dot-dash outline only. A reset spring 37 is mounted on pivot 34 and engages the leg 35 and pivot 30 so as to bias lever 32 clockwise to the reset position shown. This position is accurately determined by an adjustable cam stop 31 which is rotatably mounted on depending leg 35 of the frame 36 to engage pivot 30 as shown in FIG. 6.

The other end of the support lever 32is provided with a roller 38 which is normally engaged by releasable bell crank latch means 40. The latch means 40 is rotatably mounted on a pivot 42 supported 'by the depending 1.. leg 45 of the frame and comprises a bell crank lever 43 having a substantially horizontal leg portion 44 and an up-right portion 45. In order to provide for reducing the force required to move the latch means 40 and release the roller 38, a toggle lever 46 is pivotally mounted on the up-right leg 45 of the lever 43 by means of a pivot 46. This toggle lever is provided with a shoulder 47 for setting the roller 38 and a projection 48 for engaging a lateral tab 49 of the up-right leg which is adapted to engage the edge of the depending leg 35 of the frame when biased in a clockwise direction by means of a resetting spring 50, so as to maintain the pivot 46 in a slightly overcenter position.

In order to provide for opening and closing the switch 10, a toggle means 52 is provided, comprising as shown in FIG. 2, a pair of levers 53 and 54 which have a common overcenter toggle pivot 55. The lever 53 is connected to the operating lever 28 by a pivot 57 while the lever 54 is pivotally mounted on the casting 14 by means of a pivot 58. The lever 54 is provided with a handle extension 60 which projects through an opening 61 in the side wall of the casting 14 into a hooded extension 62, where it is accessible for manually operating the switch. The handle extension 60 is provided with an adjustable stop such as a bolt 64 which is threadedly mounted in the hooded extension 62, so as to locate the pivot 55 in a slightly overcenter position when the switch is closed.

In order to provide for closing the switch 10 electromagnetically, a solenoid 66 is provided having an armature 67 which is pivotally connected to the handle 54 by means of a pivot 68 for operating the lever 54 in a direction to move the toggle pivot 55 downwardly to its overcenter position. The solenoid 66 is positioned between a substantially U-shaped pole piece 70 and a plate 72 which are secured together by means of bolts 73. The plate 72 is supported from the casting 14 by means of bolts and spacers 75 secured to bosses 76 and 77 extending downwardly from the casting 14 and armature 67 extends through an opening therein. A cut-off switch 80 is provided for the solenoid 66, being mounted on the pole piece 70 so as to be actuated by the armature 67 to interrupt the energizing circuit for the solenoid 66 when the switch 10 is closed.

To provide for opening the switch 10 in response to a loss of voltage on the circuit in which it is connected, the usual sectionalizer counter is omitted, and instead, a voltage responsive time delay device 82 is provided. As shown in FIGS. 1, 3 and 5, this time delay device may be of the dashpot type and is mounted on a panel 83 in an enclosure 84 which is mounted on the casting 14 by means of a conduit 85 which provides a connection between the control enclosure and the interior of the casting 14. A time delay relay 86 of the plug-in type is also mounted on the panel 83 having a bimetallic switch member 86' and a 'heater 87 for controlling energization of the solenoid 66 in a manner which will hereinafter-be described.

In order to provide for releasing the latch means 40 in accordance with the teachings of the present invention, in response to loss of voltage, an L-shaped trip lever 88 is pivotally mounted by means of an L-shaped bracket 89 so as to have one end of the horizontal leg 88h positioned beneath the horizontal leg 44 of the bell crank lever 43, as shown in FIGS. 2, 4 and 7. A spring 81 is connected between pivot 57 and the horizontal leg 8811 of trip lever 88 to bias the lever clockwise to trip lever 43 when released. The end of the vertical leg 88v of the lever 88 is positioned in a recess 78 of a bell crank trigger 78 which is mounted on a pivot 79 and biased clockwise by a spring 92 to engage the leg 88v'of trip lever 88. The trigger is actuated counterclockwise to r'elease lever 88 by a flexible Bowden control wire 90 which slides in a flexible sleeve 90" which is secured at one end by means of a clamp 91 mounted on the bracket 89 and extends through the conduit to the time delay device 82 where it is anchored by means of a clamp 93. As shown schematically in FIG. 5, the dashpot device 82 comprises a solenoid 95 which, when energized, holds an armature 96 down against the biasing force of a spring 97. The armature 96 is delayed in its upward motion when the solenoid 95 is deenergized, by means of a diaphragm 98 forming a part of a dashpot 99 which is. provided with an adjustable valve 100 for controlling venting of the dashpot. A switch 101 is provided for disconnecting the solenoid 95 and heater 87 from a source of electrical energy.

In accordance with the teaching of application Serial No. 517,040, and now Patent No. 2,832,010 in order to provide a positive operating force for actuating the trip lever 88 in response to movement of the armature 96, a latch mechanism may be provided comprising a lever 102 which is pivotally mounted by means of a pivot 103 secured to a bracket 104 located adjacent the lower end of the solenoid 95. The flexible control wire 90 is connected adjacent the remote end of the lever 102. A latch lever 104 is pivotally mounted on the bracket 104 so as to normally engage one edge of an opening 107 in the lever 102. A spring 108 connected between a point adjacent the end of the lever 102 and the latch 104 at a point near pi-vot maintains the levers in operating relation. A collar :110 is provided on an extension 111 of the armature 96 for engaging the free end of the latch 104 to withdraw it from the opening 107 after predetermined movement of the armature 96. This prevents movement of the lever 102 during initial movement of the armature 96 and provides for sudden actuation of the lever 102 by spring 108 when the latch 104 is released. Positive movement of the flexible control wire 90 to release the latch means 40 and open the switch is therefore insured.

Reset of hell crank lever 43 occurs when the switch 10 opens and lever 32 is raised, by the lever 28 rocking about pivot 42 as the full open position is approached. Lever 43 is reset by spring 50, and trigger spring 81 is released from tension by pivot 57 dropping. This permits lever 88 to be reset readily by lever 43, trigger 78 being reset by spring 92 when cable 90 is retracted by reset of time delay device 82 when voltage returns.

Referring particularly to FIG. 5, it will be seen that a distribution circuit may be provided with a reclosing circuit breaker 115 of any suitable type well-known in the art for providling a predetermined number of closely successive interruptions of the circuit in response to a fault distribution before locking open to completely deenergize the circuit. Load circuits 116 and 117 being supplied by the circuit breaker 115 may be provided with sectionalizing switches 10 and 10' of the type hereinbefore described. The time delay afforded by the time delay device 82 is sufiicient to prevent opening of the switches 10 and 10 during the operating cycle of a plurality of successive openings and closings of the reclosing circuit breaker 115, so that the switches 10 open only in response to a loss of voltage on the load circuits 116 and 117 such as would be occasioned by lock-out operation of the circuit breaker 115.

When such lock-out operation occurs, the solenoid 95 of the time delay device 82 is deenergized by reason of loss of voltage from the distribution transformer 118 from which operating voltage is derived. The spring 97 operates to bias the armature 96 upwardly. Movement of the armature in this direction is delayed by application of the dashpot 99. After a predetermined time delay, the armature 96 moves upwardly a sufficient distance for the collar 110 to engage the lip of the latch lever 104. Continued movement of the armature 96 upwardly.

impulse motion is transmitted by means of the control wire 90 to trigger 78 which is moved counterclockwise to release the trip lever 88, which rotates under the force exerted by spring '81 in a clockwise direction causing the bell crank lever 43 to be actuated in a counterclockwise direction. Movement of the bell crank lever 43 in a counterclockwise direction breaks the toggle relation between the bell crank lever 43 and the toggle lever 46 so that the toggle lever moves in a clockwise direction collapsing the toggle relation and releasing the roller 38. The support lever 32 will open, dropping the normally fixed pivot 30 of the lever 28 and breaking the overcenter toggle relation between levers 53 and 54, and opening the contacts 18, 18 and 20.

The switches and 10 will remain open until the reclosing circuit breaker is reclosed. Upon closing of the circuit breaker 115, voltage is applied to the distribution transformer 118 and the time delay relay 86 is activated by reason of its heater 87 being energized. This causes deflection of the bimetallic element 86' closing contacts 86a and 86b to shunt the heater 87 and provide a low impedance energizing circuit for the solenoid 66 through the cut-01f switch 80, after a predetermined time delay. The solenoid 66 thereupon actuates the armature 67 in a direction to pull the overcenter toggle link 55 downwardly to its overcenter toggle position to effect closing of the switch. Opening of cut-ofii switch 80 disconnects the solenoid 95 and heater 87 from the source so that the heater is not continuously energized, and can cool off so as to give consistent timing, even after openings of fairly short duration.

From the above description and accompanying drawings, it will be apparent that I have provided, in a simple and effective manner, for reducing the tripping force necessary and opening the contacts of a sectionalizing switch in response to a loss of voltage and for effecting reclosure thereof, a predetermined time after voltage is restored. By using a spring-biased trip lever with a trigger lever, the tripping force necessary is reduced from a variable quantity on the order of from 4 to 16 ounces to one ounce or less, and positive operation of the switch is assured. By connecting the trip lever spring to the terminal pivot of the manual operating toggle, the spring is stressed only when the switch is closed. This helps reset when the switch is open. The dashpot release latch permits triggering a relatively strong spring which is stressed by the solenoid in its most powerful operating range, to impart a definite operating impulse to the bell crank latch trigger, no matter how delayed the operation of the delay device. The holding solenoid resets the trip latch immediately so that the latch is always reset by the end of the closing time delay period. This provides for more positive operation in a simple and reliable manner, of a switch for automatically sectionalizing different load circuits whenever they are deenergized by the opening of their circuit breaker and permitting selective reclosure of them at different timed intervals so as to limit the inrush current caused by a loss of diversity due to the circuit remaining deenergized. The requirements for close manufacturing tolerances are reduced and the necessity for close adjustments is eliminated.

Since certain changes may be made in the above described construction and diflerent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the above description and shown in the accompanying drawings, shall be considered as illustrative and not in a limiting sense.

I claim as my invention:

1. A switch comprising, separable contacts, an operating lever for opening and closing said contacts, a supporting lever pivotally mounted at one end, said operating lever being pivotally attached to the supporting lever intermediate its ends, a toggle linkage pivotally attached to the operating lever for actuating the operating lever about its pivotal support, a latch releasably engaging the sup porting lever at the end opposite its pivoted end, a trip lever for releasing the latch to open the contacts independently of said toggle linkage, a spring for biasing the trip lever to release the latch, said spring being connected to the operating lever to be energized only when the contacts are closed, a trigger holding the trip lever against the bias of the spring, tripping means for releasing said trigger, and said operating lever moving to a position in which said spring is deenergized to facilitate resetting of said latch and said trip lever when the contacts are opened.

2. A switch comprising, separable contacts, an operating lever for opening and closing said contacts, a supporting lever pivotally mounted at one end, said operating lever being pivotally attached to the supporting lever intermediate its ends, a toggle linkage pivotally attached to the operating lever for actuating the operating lever about its pivotal support, a latch releasably engaging the supporting lever at the end opposite its pivoted end, a trip lever for releasing the latch to open the contacts independently of said toggle linkage, a tripping spring for biasing the trip lever to release the latch, said tripping spring having one end attached to the trip lever and the other end attached to the operating lever at the point of attachment for the toggle linkage, said tripping spring being stressed only when the contacts are closed by the operating lever, a trigger holding the trip lever against the bias of the tripping spring, tripping means for releasing said trigger, spring means biasing said latch to a reset position, and said operating lever being moved to a position in which said tripping spring is unstressed to facilitate resetting of said latch and said trip lever when the contacts are opened.

References Cited in the file of this patent UNITED STATES PATENTS 650,425 Scott May 29, 1900 2,521,194 Van Ryan Sept. 5, 1950 2,654,009 Tremblay et al. Sept. 29, 1953 2,654,053 Wallace Sept. 29, 1953 2,694,789 Wilckens Nov. 16, 1954 2,739,270 Edwards Mar. 20, 1956 2,753,424 Peek July 3, 1956 2,795,671 Edwards June 11, 1957 2,832,010 Chabala Apr. 22, 1958 2,836,769 Sandin May 27, 1958 2,866,031 Findley 2.. Dec. 23, 1958

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