US3310643A - Two position snap action positive indication switch - Google Patents

Description

March 21, 1967 w. F. DRIPPS TWO POSITION SNAP ACTION POSITIVE INDICATION SWITCH Filed June 28, 1965 2 Sheets-Sheet 1 March 21, 1967 w. F. DRIPPS TWO POSITION SNAP ACTION POSITIVE INDICATION SWITCH Filed June 28, 1965 2 Sheets-Sheet 2 United States Patent 3,310,643 TWO POSITION SNAI ACTION POSITIVE. INDICATION SWITQI-I William F. Dripps, Pittsfield, Mass, assignor to General Electric Company, a corporation of New York Filed June 28, 1965, Ser. No. 467,648 1 Claim. (Cl. 200-67) This invention relates to electrical switches and, more particularly, to a two position, snap action, positive indicating switch.

The switches of this invention find special utility in distribution loop feed systems which are used to distribute electrical power to utility consumers. In a loop feed system a plurality of distribution transformers are connected in an open loop to a source of electrical power. In these systems each distribution transformer may be connected to either one of two energized power lines. Thus when a transformer or cable section develops a fault which requires its removal the remaining transformers in the system may be energized.

A principal problem arising with loop feed systems is the need for switching means for removing transformers from the energized lines as desired, or switches to sectionalize a portion of the loop feed system. Sectionalizing as used herein means to isolate a cable connecting two adjacent transformers in the system. For example, when it is desired to inspect the cable connecting adjacent transformers, or to replace such cable, it is necessary that this cable be de-energized. This may be done by use of switches within the transformer, disconnecting the cable from the transformer at each end.

Many present day switcheswhich are available either lack the necessary snap action for opening and closing or lack a means to positively indicate the switch position. Snap action, as used herein, means that the speed of contact movement, either opening or closing, is independent of the speed of movement of the switch handle. As is well understood, the lines used in energizing the transformer in a loop feed system carry a large quantity of electrical power. Generally, the power carried in the lines is the sum of the load on the various transformers connected in the loop. Opening contacts of a switch carrying a large electrical power draws a substantial are between the opening contacts. In opening such a switch it is necessary that a snap action be provided so that the arc will break during the opening of the contacts, for if the arc were not broken, even though the contacts were open, the energy would continue to flow across the open contacts through the arc. Of course, snap action is also necessary on contact closing to prevent pitting and deterioration of the contacts and also to prevent welding of such contacts should they close on overload currents.

Also, as will be understood it is necessary that switches be provided with a positive indication of the position of the switch contacts. In many instances contacts become welded when being used beyond their rated capacity. In such cases many switches could have their handles moved to the open switch position and remain in such position without the switch contacts having been open. Obviously, a false indication of the actual position of the switch contacts can be dangerous to men working on the equipment. From the above it will be apparent that there is t a need for a snap acting switch providing a positive indication of the position of the switch contacts.

Therefore, it is one object of this invention to provide a snap acting switch which will positively indicate the position of the switch contacts.

A further object of this invention is to provide a positive indicating snap acting switch which may be used in distribution loop feed systems.

A still further object of this invention is to provide a positive indicating switch having a rapid snap action in both opening and closing of the switch contacts.

In carrying out this invention in one form a switch is provided having a fixed contact and a movable contact. The movable contact is pivotally mounted at one end on a mounting member and engages the fixed contact with its other end. A link member is pivotally connected at one end to the central part of the movable contact. An actuating member is provided rotatably mounted in the mounting member having an operating handle at one end and an operating arm on the other end. A crank arm is pivotally mounted at its mid-point to the actuating member and is pivotally connected at one end to the other end of the link member. A spring guide member is provided pivotally connected to the other end of the crank arm, forming therewith a toggle mechanism. A guide portion of the spring guide member extends through a slot in the operating arm and a spring is mounted on the guide portion and contained between both the guide and the operating arm. Movement of the operating handle causes the operating arm to move compressing the spring on the guide. When the operating arm reaches the limit of its movement, the spring guide and crank arm are toggled such that the force of the spring is released, pivoting the crank arm about the actuating member and causing the link member to move, snapping the movable contact into or out of engagement with the fixed contact. If the operating arm does not move far enough to operate the toggle mechanism, the spring will cause the operating arm, and with it the operating handle, to return to its original position, thus preventing the operating handle from giving a false indication of the position of the contacts.

The invention which is sought to be protected will be clearly pointed out and distinctly claimed in the claims appended hereto. However, it is believed that this invention and the manner in which its various objects and advantages are obtained, as well as other objects and advantages thereof, will be better understood from the following detailed description of a preferred embodiment thereof, particularly when considered in connection with the accompanying drawings, in which:

FIGURE 1 is a schematic representation of a loop feed distribution sytsem which may be supplied with the switches of this invention;

FIGURE 2 is a plan view of a preferred form of snap acting switch according to this invention;

FIGURE 3 is a top view of the switch shown in FIG. 2 partially in section; and

FIGURE 4 is a fragmentary view of one form of operating handle for the switch of this invention.

Referring now to the drawings in which like numerals are used to indicate like parts throughout the various views thereof, there is shown a novel two position, snap acting, positive indicating switch according to a preferred embodiment of this invention. This novel switch finds special utility in a loop feed distribution system such as is shown schematically in FIG. 1. Referring now to FIG. 1 the loop feed system is shown as comprising a plurality of distribution transformers 12, 14, 16 and 18 connected in an open loop to a source of electrical power 10. The loop feed system from the source 10 is shown as being open between transformers 14 and 16. Distribution transformers 12 and 14 are serially connected to power source 10 by line 20, while transformers 16 and 18 are serially connected to source 10 through line 22. Should it be desirable to remove one of the transformers from service, for example transformer 16, then it can be seen that various switches may be opened to de-energize transformer 16. The remaining transformers may still be energized. As is apparent, transformers 12 and 14 will still be energized by means of line 28, while transformer 18 is energize by the line 22. Of course, should another transformer require removal, by merely changing the position of the switches the remaining transformers will still be energized from lines 20 and/ or 22.

To remove transformer 16 from the source it is necessary to provide a means for disconnecting line 24 between transformers 14 and 16 and also to disconnect the line 26 between the transformers 16 and 18. This dis-connection may be obtained by the switch means of this invention. As will be understood, it is desirable that the lines be disconnected from the adjacent trans-formers to prevent a live wire from being present in the disconnected transfonmer. In the above example the switch in transformer 14, shown schematically as switch 28, may be used to disconnect transformer 14 from the line 24. The switch 30 in transformer 18 may be used to disconnect transformer 18 from the line 26. This, of course, removes transformer 16 from electrical power and will allow repairs or change-out to be made without disturbing the energization of the remaining transformers in the system.

At times it is desirable to disconnect one of the lines, such as the line 24 between transformers 14 and 16, such that the line may be inspected, or replaced, if necessary. The switch 32 in transformer 16 will disconnect line 24 from transformer 16, while switch 28 in transformer 14 will disconnect transformer 14 from the line 24. This will provide the desired sectionalizing of line 2-4, removing it from service, without disturbing the energization of any of the transformers in the system.

The novel two position, snap acting, positive indicating switch of this invention is uniquely designed for use in loop feed distribution systems. However, it will be apparent from the "following description that the switch of this invention is not limited to such use.

Considering now FIGURES 2, 3 and 4 of the drawings, a preferred embodiment of the snap acting, positive indicating switch of this invention will be described. As shown, the switch comprises an actuating member which is rotatably mounted in a mounting member 42 by means of bearings 44. As will be understood, mounting member 42 may be secured within a transformer or other enclosing means, as is indicated by sectioned wall 46. Of course, mounting member 42 may form a portion of the transformer tank or other enclosing means. The actuating member 40 is provided with an operating handle 48 firmly secured thereto as, for example, by bolt or pin 50. Operating handle 48 will extend outside of the enclosure and will be readily available to a lineman for operating of the switch. The operating handle 48 is provided with an indicator 52 which, in conjunction with indicia on the enclosing means, will indicate the position of the switch contacts. This is clearly apparent in FIG. 4 of the drawings where indicator 52 is shown pointing to the closed legend on wall 46.

In the preferred form of the invention which is shown in the drawings, the switch is provided with a fixed contact 54 and a movable contact 56. The fixed contact 54 is secured to a flange 58 of the mounting member 42 and is provided with a terminal means such as terminal 60 to which a conductor may be attached. As will be understood the contact 54 will be insulated from mounting member 42, for example as indicated by the insulating means 62. The movable contact 56 is pivotally mounted and electrically connected to pivot member 64 which is also mounted on the flange 58 and insulated therefrom by insulation 66. The pivot member 64 is provided with a terminal means 68, as shown, to which a conductor may be connected. As will be understood when the switch is mounted in a transformer such as, for example, transformer 14 of FIG. 1, one contact, such as the fixed contact 54, will be connected to the high voltage windings of the transformer. The other contact, such as movable contact 56, will be connected to a line such as line guide 84 as shown.

4 24 which will be used to energize the transformer. In the preferred form of the invention shown, the fixed contact 54 is in the form of a jaw member, while the movable contact 56 is a blade member. As shown in FIG. 2 the blade member 56 is tightly held by the jaws of contact 54 when the contacts are closed.

Pivotally attached to the movable blade or contact 56 is one end of a link member '78. Link member is preferably attached by means of a pin or bolt 72 at substantially the mid-point of blade 56. The opposite end of link 70 is pivotally connected to one end of a crank arm 74 as, for example, by the pin or bolt 76. The crank arm 74 is pivotally mounted at substantially its mid-point to a reduced portion 78 of the actuating member 40. This is clearly shown in FIG. 3 of the drawings. The opposite end of crank arm 74 is pivoted to one end of a spring guide member 80 as, for example, by pin or bolt 82.

The spring guide member 80 is provided with a guide portion 84. A compression spring 86 is mounted on the As can be seen, one end of compression spring 86 fits against a shoulder 88 which is formed by the body portion of the spring guide member 80. An operating arm 90 is fixed to the actuating member 40 such as by pin 92 shown in FIG. 3 of the drawings. The operating arm 90 is provided with a flange portion 94 having a slot 96 therein. Guide portion 84 of the spring guide member 80 rides in the slot 96 of the flange 94. The other end of spring 86 fits against flange 94, as shown. Thus, the spring 86 is contained between the shoulder 88 of the spring guide member 80 and the flange 94 of the operating arm 90.

As will be apparent, the crank arm 74 and the spring guide member 88 form a spring toggle mechanism. When the crank arm 74 and guide member 80 are at an angle to each other, as shown in full lines in FIG. 2, the spring 86 will act to force operating arm 96 downward against stop member 98. However, when crank arm 74 and spring guide member 86) are moved such that the angular relation is opposite to that shown, the force of spring 86 will hold operating arm 96 against the upper stop 100.

From the above description it is believed that the operation of the novel snap acting, positive indicating switch of this invention will be apparent. As shown in full lines in FIG. 2, the switch is in closed position, that is, movable contact 56 is tightly held in the jaw contact 54. To open the switch a lineman would insert a switch stick in the operating handle 48 and rotate handle 48 toward the open indication on wall 46. Considering specifically FIG. 2, movement of the handle 48 will rotate the actuating member 40 causing operating arm 90 to rotate counterclockwise as indicated by the arrow. As operating arm 90 moves into the position shown in phantom lines in FIG. 2, spring guide member 80 will pivot clockwise about pin 82, moving guide portion 84 in the same direction as the operating arm 90. As will be clear, guide portion 84 will slide through slot 96 and spring 86 will be compressed between shoulder 88 and flange 94, thus cocking the toggle mechanism. As the operating arm 90 moves into the position shown in phantom lines, the edge 104 of spring guide member 80 will strike stop forcing pivot pin 82 and crank arm 74 to move in a clockwise direction about reduced portion 78 of the actuating member 40. As will be apparent from FIG. 2, edge 164 of spring guide member 80 will strike stop 100 before operating arm 90 engages the stop 108. Further movement of operating arm 96 toward stop 100 will cause spring guide member 80 to effectively pivot counterclockwise about stop and edge 104. This pivoting motion of spring guide member 86 forces pin 82 and related end of crank arm 74 to rotate clockwise about reduced portion 78 moving link 70 upward and moving contact 56 toward open position. Thus a positive force is transmitted from the operating handle 48 through the levers to movable contact 56.

This positive force provides a prying action to movable contact 56, making it possible to break contact 56 loose from the jaws of contact 54 if roughening or welding of the contacts had occurred on previous operations of the switch.

As the operating arm 90 moves to position against stop 100, the crank arm 74 rotates clockwise as discussed above. Pin 82 will cross the line of centers of the toggle mechanism. This will break the toggle mechanism releasing the force of spring 86. Spring 86 will snap the crank arm in a clockwise direction about portion 78 to the position shown in phantom lines in FIG. 2. As will v be clear, the snap action will snap the movable contact 56 away from contact 54 by movement of link 70 as is shown in the phantom lines of FIG. 2. Obviously, to close contacts 54 and 56 rotation of handlev 48 is reversed and the toggle mechanism formed by crank arm 74 and spring guide member 80 will be cocked and then broken against stop 98, snapping contact 56 into the jaw contact 54.

As will be clear from the above, if the movable contact 56 should be frozen in either an open or closed position the operating handle will not remain in a position to provide an opposite indication. For example, if contact 56 is frozen in a closed position the toggle formed by crank arm 74 and spring guide member 80 will not be elfective to move crank arm 74 in a clockwise direction. Therefore, the toggle will remain cocked against the stop 100. When the operating handle 48 is released the toggle will operate to force the operating arm 90 downward against the stop 98 as shown in full lines in FIG. 2. Movement of the operating arm 90 will rotate the indicator 52 and operating handle 48 to the closed indicating position.

From the above descripion it will be apparent that a novel, snap acting, positive indicating switch has been provided which will find utility in loop feed distribution systems. However, it will be apparent that the switch of this invention has many uses and is not limited to such systems.

While there has been shown and described the present preferred embodiment of this invention, it will be obvious to those skilled in the art that changes may be made in various structural details. For example, it is not necessary that the spring toggle mechanism and the operating arm be pivoted about the same point as shown in the preferred embodiment. Also, it will be apparent that the operating handle may be actuated by another link mechanism, if desired. These, and other structural changes may be made without departing from the spirit and scope of the invention, particularly as defined in the appended claim.

What is claimed as new and which it is desired to secure by Letters Patent of the United States is:

A two position, snap action switch comprising:

(A) a mounting member,

(B) an actuating member rotatably mounted in said mounting member,

(C) a fixed contact mounted on said mounting member,

(D) a movable contact pivotally mounted on said mounting member and movable into and out of engagement with said fixed contact,

(B) an operating arm fixedly mounted on said actuating member,

(1) said operating arm being movable to either of two positions,

(F) stop means mounted on said mounting member for limiting movement of said operating arm to said two positions,

(G) a crank arm pivotally mounted at substantially its midpoint on said mounting member, (H) a spring guide member,

(1) one end of said spring guide pivotally connected to one end of said crank arm, (2) the other end of said spring guide slidably positioned in a portion of said operating arm, (3) portions on said spring guide member contacting said stop means on operation of the switch, (I) a spring mounted on said spring guide,

(1) said spring contained between said spring guide and said.portion of said operating arm, (I) a link member having one end pivotally connected to the other end of said crank arm,

( 1) the other end of said link member pivotally connected to said movable contact, whereby movement of said actuating member moves said operating arm from one position toward its other position compressing said spring between said spring guide and said operating arm, and on further movement of said operating arm to'said other position said portions of said spring guide member contact said stop means and apply a positive force to said link member to move said movable contact, said stop means being efiective to move said crank arm and said spring guide means to release said compressed spring pivoting said crank arm about said actuating member causing said link member to move said movable contact with a snap action into or out of engagement with said fixed contact.

References Cited by the Examiner UNITED STATES PATENTS 3/1924 Baxter. 12/1924 Penn.

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