US3522397A - Elongated sectionalizing switch - Google Patents

Description

Jul 28, 1970 D. E. DODSON ET AL ELONGATED SECTIONALIZING SWITCH Filed Aug. "28, 19 67 3 Sheets-Sheet 1 Z! 2: Mm I? July 28, 1970 D. E. DODSON ET AL 3,522,397

ELONGATED SECTIQNALIZING SWITCH Filed Aug. 28, 1967 3 Sheets-Sheet 3 36 I 1 40 o 29 J38 5 2k 114 ii g1 5 L 78 130 112 94 ii 132 Li l I 11 b a 1111 United States Patent 3,522,397 ELONGATED SECTIONALIZING SWITCH Donald E. Dodson, Washington, and John E. Smith, Murray, Pa., assignors to McGraw-Edison Company, Elgin, 11]., a corporation of Delaware Filed Aug. 28, 1967, Ser. No. 663,706

Int. Cl. H01h 15/18 US. Cl. 200-78 4 Claims ABSTRACT OF THE DISCLOSURE A switch having a fixed contact and a spring loaded moving contact structure actuated by a plunger arm and moved along a straight line to engage or be disengaged from the fixed contact. The moving contact is held in its respective engaged and disengaged positions by a dog at each position. Movement of the plunger arm either toward or away from the moving contact compresses a spring against the moving contact and then trips a dog to cause the moving contact to snap from one of its engaged or disengaged positions to the other position.

BACKGROUND OF THE INVENTION This invention relates to electrical distribution systems and, in particular, to sectionalizing switches for underground distribution systems.

Overhead electrical distribution systems are esthctically displeasing and detract from the beauty of residential areas. The modern concept of residential distribution accordingly places all components of the system underground. Due to problems of bulkiness and high expense, however, the old style or subway systems are not considered feasible. Utilities prefer an underground system which compares favorably with the cost of an equivalent overhead system and a system design that will permit loading and operating practices closely resembling their existing system.

General operation and maintenance of any system requires provisions for sectionalizing the feeder. This is commonly accomplished on overhead lines through the use of low cost air disconnects. Such devices are not suitable for underground use where flooding and submerged operation are recognized conditions. From the viewpoint of overall cost and convenience of operation, a sectionalizing switch installed within the underground transformer tank itself is the most desirable solution to the problem. On the other hand, switch designs heretofore available for installation within the transformer tank cause problems of physical size and location resulting in significant increases in the size of the transformer tank, materials and fabrication cost.

SUMMARY OF THE INVENTION It is an object of the invention to provide a sectionalizing switch which may be mounted within a transformer tank without enlarging the tank due to the mounting of the switch therein.

Another object of the invention is to provide a sectionalizing switch that may be mounted within a transformer tank and operated from the outside of the tank.

It is another object of the invention to provide a sectionalizing switch that may be mounted within the transformer tank and to which access may be had from a posi tion directly above the transformer tank for the operation thereof with the transformer tank entirely closed.

A still further object of the invention is to provide a distribution switch which may be mounted within a transformer tank on the cover of the transformer tank and removed from within the transformer tank by removal of the cover.

A further object of the invention is to provide a sectionalizing switch for mounting within a transformer tank which has a positive, rapid, engaging and disengaging operation of its contacts upon the application of a minimal amount of manual force to effect an engaging or disengaging operation.

Stillanother object of the invention is to provide a compact transformer system in which the transformer and all auxiliary components including a sectionalizing switch may be located within the transformer tank.

These and other objects and advantages of the invention will be more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings wherein:

DESCRIPTION OF THE DRAWING FIG. 1 is a view of a transformer embodying the invention with a portion of the casing broken away to illustrate the internal arrangement;

FIG. 2 is a plan view of the transformer of FIG. 1 with a portion of the cover broken away to show the connection of a sectionalizing switch to a transformer;

FIG. 3 is a sectional view of a sectionalizing switch shown in its open or disengaged position;

FIG. 4 is a sectional view of the sectionalizing switch of FIG. 3 shown in its closed or engaged position;

FIG. 5 is a partial sectional view taken on line 55 of FIG. 3;

FIG. 6 is a sectional view similar to FIG. 5 with a portion broken away to show the interior of the sectionalizing switch.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the transformer tank 2 is shown positioned below ground level with the feeder terminals 6 and 8 extending to the cover 4 into the interior of the transformer tank 2. The transformer 10 is shown in FIG. 1 as being mounted within the transformer tank 2 and immersed in oil 12.

The switches, indicated generally by the numerals 24 and 26 are shown in FIG. 1 as being supported on the transformer cover 4 and extending from the exterior of the transformer tank 2 through the openings 20 and 22 in the transformer cover 4 into the interior of the transformer tank 2 adjacent the transformer 10. The flexible primary leads 14 and 16 are corrected within the interior of the transformer tank 2 between the feeder terminals 6 and 8 and the terminal lugs 28 on the switches 24 and 26. The terminal ears 30 of switches 24 and 26 are con nected together and to the high voltage lead 18 of transformer 10 by the nut and bolt 32.

The switches 24 and 26, shown in detail in FIGS. 3 and 4, are identical in construction and operation and therefore only one will be described. The switch housing 34 may be of an electrically insulating material such as paper-base phenolic laminate or a molded insulating plastic. The switch housing 34 is shown as partly tubular in form, but may be of any form in which it will movably support the moving switch elements. The switch housing 34 for each of the switches 24 and 26 includes a plug 36 which protrudes through the openings 20 and 22 in the transformer cover 4 and which is attached at the end 38 of the switch housing 34 by studs 40. The switch housing 34 is also supported by studs 40 on the cover 4 of the transformer tank 2.

The trip mechanism 42 includes the actuating rod 44 which is slidably supported within the opening 46 in plug 36 and extends from the interior of the transformer tank 2 to the position outside of the transformer tank 2 above the cover 4. A handle 48 is attached to the upper end 50 of the actuating rod 44 and may be used to impart reversible sliding movement to the actuating rod 44. The handle 50 is provided with an eye 52 which may be used to operate the switch 24 with a hot stick (not shown) if desired. A flexible cover or boot 54 is attached between the handle 48 and the plug 36 to enclose the upper end 50 of the actuating rod 44. The boot 54 thus prevents dirt or moisture which might interfere with operation of the actuating rod 44 or transformer from access to the actuating rod 44 and the interior of the transformer tank 2. A hood 56 for protection of the actuating rod 44 and handle 48 from accidental damage or operation is attached to the top of the transformer cover 4 by the studs 40.

A stationary contact indicated generally by the numeral 60 is aflixed to the switch housing 34 at its end 58. The stationary contact 60 comprises fingers 62 and terminal ear 30 mounted on the switch housing 34. A spring 66 is attached to the fingers 62 and urges the fingers 62 toward each other. (See FIGS. 1 and 3.)

As shown in FIGS. 3 and 4, a movable contact means 70 is slidably mounted on the interior portion 72 of the switch housing 34 and is movable along the longitudinal axis of the switch housing 34. The movable contact means 70 includes a contact element or blade 74, an insulator 76 and a tubular portion 78. The insulator 76 supports the contact blade 74 in an electrically insulated relationship with the tubular portion 78. The insulator 76 may be of any suitable insulation material, such as a paper-base phenolic laminate or a molded insulating plastic material. The contact blade 74, has a terminal lug 28 extending through the slot 68 in the switch housing 34. The contact blade 74 is formed in a shape capable of making a firm electrical engagement with the stationary contact 60. The contact blade 74 is shown in FIG. 3 in an open or disengaged position with the stationary contact 60 and in FIG. 4 in a closed or engaged position with the stationary contact 60. As will be hereinafter described, the contact blade 74 may be alternatively moved from an engaged to a disengaged position and from a disengaged to an engaged position.

The tubular portion 78 of the movable contact means 70 slidably engages and extends toward the trip mechanism 42. The tubular portion 80 of the trip mechanism 42 is positioned within the tubular portion 78 of the movable contact means 70 resulting in the formation of an annular passageway 100 between the two tubular portions 78 and 80. The tubular portion 78 of the movable contact means 70 is provided with an internal shoulder 82 adjacent the end 84 of the movable contact means 70. The end 84 of the movable contact means 70 abuts the plug 36 when the contact blade 74 is held by the movable contact means 70 in its open or disengaged position. The trip mechanism 42 includes an external shoulder 86 positioned adjacent the upper end 86 of tubular portion 80 and an external shoulder 92 position adjacent its inner end 90. The purpose of the external shoulder 86 is to limit the distance the trip mechanism of 42 may move in a direction away from the stationary contact 60. The trip mechanism 42 is also provided with a projecting portion or dog 94 afi'ixed to its inner end and movable within the slot 96 in the tubular portion 78 of the movable contact means 70. A helical spring 98 is supported within the annular passageway 100 and engages the internal shoulder 82 of the tubular portion 78 of the movable contact means 70 and the external shoulder 92 on the inner end 90 of the trip mechanism 42. Another helical spring 102 is supported within the tubular portion 80 of the trip mechanism 42 and fits onto pin 104 projecting from the interior bottom end 106 of the tubular portion 70 of movable contact means 70. The helical spring 102 engages the interior end 108 of the tubular portion 80 of the trip mechanism 42 and the shoulder 110 formed in the pin 104.

The switch housing 34 includes a channel piece 112 (see FIGS. 3 and 4) which is affixed to the switch housing 34 by the clamping bands 114, as can be seen in FIG. 6. It should be readily understood that the channel piece 112 may be affixed to the switch housig 34 by any other means or the channel piece 112 may be formed as an integral part of the switch housing 34, for example where the switch housing 34 is made from a molded insulating plastic material. The holding or latching mechanism, indicated generally by the numeral 116, includes latching members 118 and 120 which are pivotally supported on the channel piece 112 by pins 122 and 124. The access openings and 132 in switch housing 34, shown in FIG. 5, are provided to allow the ends 126 and 128 of latching members 118 and 120 to be urged into engagement with the movable contact means 70 by springs 134 and 136. The springs 134 and 136 are respectively mounted on pins 122 and 124. When the movable contact means 70 moves contact blade 74 to its closed or engaged position, the end 128 of latching member 120 moves through the access opening 132 and against the lip on the opening 144 (see FIG. 6) of tubular member 70 to hold the contact blade 74 in its engaged position. When the movable contact means 70 moves contact blade 74 to its open or disengaged position, the end 128 of latching member 120 moves into the opening 142 in tubular member 70 and against lip 138 to hold the contact *blade 74 in its disengaged position.

The movable contact means 70 is moved toward the stationary contact 60 to move the contact blade 74 from a disengaged to an engaged position with stationary contact 74 by movement of the handle 48 and trip mechanism 42 toward the stationary contact 60. Since the latching member 120 is holding the movable contact means 70' in the disengaged position, the helical spring 102 will be compressed or loaded between the interior end 108 of the tubular portion 80 of the trip mechanism 42 and the shoulder 110 on the pin 104. However, as the inner end 90 of the trip mechanism 42 approaches the interior bottom end 106 of the tubular portion 78, the projecting portion or dog 94 of trip mechanism 42 engages the latch member 120 to push the end 128 of the latch member 120 away from the lip 140 and release the movable contact means 70 for movement. The helical spring 98 will now quickly expand to rapidly move or snap the contact blade 74 to its engaged position with the stationary contacts 60. When the contact blade 74 is in its engaged position with the stationary contact 60, the lip 138 on opening 142 (see FIG. 6) of the movable contact means 70 will be opposite the end 126 of latch member 118. Due to the urging effect of the spring 134, the end 126 of the latch member 118 will engage the lip 138 to hold the movable contact means 70 stationary and the contact blade 74 in its engaged position with the stationary contact 60.

The contact blade 74 may be moved from a closed or engaged position to an open or disengaged position by movement of the movable contact means 70 and the trip mechanism 42 away from the stationary contact 60. Initially the contact blade 74 will not be moved from its engaged position because the latch member 118 is holding the movable contact means 70 stationaryv However, as the trip mechanism 42 moves in a direction away from the stationary contact 60 the helical spring 98 is compressed or loaded between the internal shoulder on the tubular portion of the movable contact means 70 and the external shoulder 92 on the inner end 90 of the trip mechanism 42. As the projecting portion or dog 94 on the inner end 90 of the trip mechanism 42 approaches the end 84 of the movable contact means 70 the dog 94 will engage the latch member 118 to push the end 126 of the latch member 118 away from the lip 138 on opening 142 and release the movable contact means 70 for movement away from the stationary contact 60. When the mova-ble'contact means 70 is released the helical spring 98 will quickly expand to rapidly move or snap the contact blade 74 to its disengaged or open position with the stationary contact 60. When the contact blade 74 moves to its disengaged position, the lip 140 on opening 144 of the tubular portion 70 will be engaged by the end 128 of the latching member 120 to hold the movable contact means 70 stationary and the contact blade 74 in its disengaged position.

As shown in FIG. 1, a position indicator 150 is provided for each of the switches 24 and 26. The position indicator 150 is pivotally mounted on hood 56 and held in what is designated as an open" position by spring 152 (see FIG. 2). When the handle 48 is moved toward the stationary contact 60 to result in the moving of the contact blade 74 to its engaged or closed position, the handle 48 engages the position indicator 150 to move it to What is designated as a closed position. In FIG. 2, the switch 24 is in a closed position as indicated by the position indicator 150 and the switch 26 is in an open position as indicated by the position indicator 150.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

We claim: 1. In an electrical switch construction: a support tube having first and second ends; contact means supported on said support tube adjacent said first end for efiecting an electrical connection;

movable means mounted within the support tube intermediate the first and second ends of said support tube and connected to the contact means, said movable means being slidable between a closed position and an open position for correspondingly moving the contact means to a closed position and to an open position, said movable means including a tubular portion having an open end extending toward the second end of the support tube, said tubular portion including first and second spaced apart openings positioned along a line parallel to the longitudinal axis of the tubular portion and an elongated opening connecting said first and second openings, each of said openings having a lip;

releasable holding means mounted on said support tube and having first and second latches, said first latch earing against the lip of said first opening following movement of said contact means to the open position and said second latch bearing against the lip of said second opening following movement of said contact means to the closed position to hold said contact means in the closed position;

rod means movable in opposite directions alternatively into engagement with said first and second latches for releasing said latches to enable the movable means to move the contact means to one of said open and closed positions, said rod means including an outer end slidably supported by the support tube adjacent the second end of the support tube and an inner end slidably positioned within the tubular portion of the movable means, said inner end having a dog afi'ixed thereto, said dog being positioned within said elongated opening and being movable together with the rod means to engage and release the first latch from the lip of said first opening when the rod means is moved in one direction and to engage and release the second latch from the lip of said second opening when the rod means is moved in the direction opposite to said one direction;

and resilient means engaging the movable means and rod means within the tubular member of the movable means and loaded by movement of the rod means alternatively away from and toward the contact means until said dog engages and releases one of said latches for rapidly operating the movable means to move the contact means from a closed to an open position when the rod means is moved away from said contact means and from an open to a closed position when the rod means is moved toward said contact means.

2. In an electrical switch construction:

a support tube having first and second ends;

contact means supported on said support tube adjacent said first end for effecting an electrical connection;

movable means slidably mounted within the support tube intermediate the first and second ends of said support tube and connected to the contact means, said movable means being slidable between a closed position and an open position for correspondingly moving the contact means to a closed position and to an open position, said movable means including a tubular portion having an open end extending toward the second end of the support tube and an interior bottom end positioned opposite to said open end;

releasable holding means mounted on said support tube and engaging the movable means when the latter is in its open position and in its closed position for holding the contact means in its corresponding open and closed positions following operation of the movable means wherein the contact means is moved to one of said open and closed positions;

rod means movable in opposite directions into engagement with said holding means and having an inner end comprising a tubular member slidably positioned within and spaced apart from the tubular portion of the movable means and an outer end slidably supported by the support tube adjacent the second end of the support tube for releasing said holding means upon engagement therewith to enable the movable means to move the contact means to one of said open and closed positions;

and resilient means comprising a first helical spring engaging and supported between said tubular portion and tubular member and a second helical spring having an inner end engaging and supported within said tubular member and an outer end engaging and supported on the interior bottom end of said tubular portion, said second helical spring being loaded by movement of the rod means towards the contact means until the rod means engages and releases the holding means for rapidly operating the movable means to move the contact means from an open to a closed position, said first helical spring being loaded by movement of the rod means away from the contact means until the rod means engages and releases the holding means for rapidly operating the movable means from a closed to an open position.

3. The combination of claim 2 wherein:

the tubular portion has an interior surface formed with a shoulder positioned adjacent the open end of said tubular portion and facing the inner end of said rod means, a pin projecting from the interior bottom end 8 of said tubular portion, said pin having a distal end a transformer tank having a removable cover provided extending into the interior of said tubular member with an opening therein; and a shoulder facing the inner end of said tubular and wherein said support tube is mounted on said cover portion and formed intermediate said distal end and With i116 first end of Said pp tube being P tioned within the transformer tank and the second end of said support tube projecting substantially perpendicularly above the removable cover, through said said interior bottom end; 5 the tubular member of the rod means has an external shoulder formed therein, said shoulder being positioned adjacent the inner end of the rod means and opening References Cited facing the open end of said tubular portion, and said first helical spring has opposing ends respec- 10 UNITED STATES PATENTS tively engaging the shoulder formed on the interior 1,362,661 12/1920 Zirnerman 20078 surface of said tubular portion and the external 1,380,595 6/1921 Ritz 20078 shoulder formed on the tubular member, said second ,600,127 9/1926 Nero 20078 helical spring having its outer end positioned on said 15 pin and engaging the shoulder of Said pin ROBERT K. SCHAEFER, Prlmary Examiner 4. The combination of claim 3 further comprising: D. SMITH, 111., Assistant Examiner

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