US2786919A - Fluid circuit interrupter - Google Patents

Description

March 26, 1957 C- E. CONNOLLY FLUID CIRCUIT INTERRUPTER Filed March 5, 1954 FIG. 1.

INVENTOR.

CHARLES E. CONNOLLY FLUID CIRCUIT 'INTERRUPTER Charles E. Connolly, Endicott, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application March 5, 1954, Serial No. 414,258

1 Claim. (Cl. 200-152) T he present invention relates to circuit interrupting apparatus of the fluid contact type.

An object of this invention is to provide improved fluid contact circuit interrupting means.

Another object of the invention is to furnish improved circuit breaker means of the mercury type in which very small amounts of motion are required for making and breaking a circuit.

Still another object of the present invention resides in the provision of an improved mercury contact'circuit breaker in which the circuit is broken sharply with little or no arcing.

Other objects of the invention will be pointed out in the following description and claim and illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a sectional view of a preferred embodiment of the invention;

Fig. 2 is a perspective view of said preferred embodiment; and

Fig. 3 is a sectional view of a second embodiment of the invention.

Similar reference numerals represent similar parts throughout the several views.

Referring to Figs. 1 and 2, a preferred embodiment of the invention is shown to comprise a moulded body constructed of a plastic material which is capable of undergoing bending stresses. The body is seen to comprise a central leg portion 11 and side legportions 12 and 13 on opposite sides of said central leg portion. The part of the body to which the legs are connected may be referred to as the head portion and :is illustrated by reference numeral 14. M

It will be seen that a space is provided between th central leg and each of the side legs. Between legs 11 and 12 a reservoir 15 is provided and between legs 11 and 13 a reservoir 16 is provided. Both reservoirs are identical and for this reason only reservoir 15 will be described in detail.

Fig, 1 shows the bottom 17 of the reservoir to be in the form of an accordian pleat or fold. The sides 18 (only one of which is shown) are similarly formed. It will be understood that the number of folds shown is illustrative only and that, in fact, a greater or lesser number may be provided. The folds are flexible with respect to each other so that they will pivot one on the other as in the conventional manner. Yet, they are sufficiently rigid so that they do not lose their general configuration when a pressure is created inside the reservoir. The arrangement is such that when either of legs 12 or 13 are moved toward leg 11, the volume of the reservoir associated therewith decreases.

The sides and bottom of each reservoir may be constructed of a suitable plastic material which will not contaminate the mercury which is adapted to be placed in the ited States PatentO T 7 2,786,919 Patented Mar. 26, 1957 reservoir. The plastic sides and bottom may be secured to the legs and head portions of the moulded body by any suitable technique. For example, a suitable solvent may be applied to the edges of the sides and bottom and also the portions of .the body to which they are to be attached. After the parts are placed in their correct relation, the application of suflicient pressure will seal them together.

\The head portion 14 is provided with passages 19 and 20 which extend from reservoirs 15 and 16, respectively, to a common passage 42, the last-named passage leading to a cavity 21. An aperture 22 is provided above cavity 21 and is tapped to receive screw 23. A tapped aperture 24 is provided at right angles to aperture 22 and is adapted to receive a set screw 25 which locks screw 23 in place.

Electrical connection to mercury reservoirs 15 and 16 is furnished by way of terminals 26 and 27, respectively.

The free end portions of legs 12 and 13 are tapped to permit entry therein of adjusting screws 28 and 29, respectively. Coil spring 30 is mounted on screw 28 between legs 12 and 11 while a similar spring, illustrated by numeral 31, is mounted on screw 29 between legs 13 and 11. p p 1 The means for mounting the circuit breaker may'take a number of different forms. The particular form shown includes a bracket 32 mounted on a frame member 35 by screws 33 and 34. The circuit breaker is secured to the bracket by screws 36 and 37 which enter tapped holes in leg 12.

The mounting procedure for the circuit breaker is to secure the bracket 32 .to the circuit breaker and then secure the bracket to frame member 35.

The operation of the embodiment shown in Fig. 1 will now be described in detail. Mercury may be placed in reservoirs 15 and 16 in a number of ways. For example, a hypodermic needle may be passed through passages 42 and 19 or 20 for injecting the mercury into the reservoirs. The mercury level in the passages may vary, the arrangement being such that when legs 12 and 13 have moved their maximum distances from the central leg any electrical circuit between the reservoirs will be broken. The cavity 21, which is provided above the two reservoirs is filled with an inert gas and then sealed. To insert the inert gas in cavity 21, screw 23 is backed out until it is slightly above the tapped aperture 24. This makes it possible to fill the cavity with gas to a desired pressure from said aperture. While the device is still coupled to the means for supplying the gas, screw 23 is moved down past aperture 24 to the position shown,

, thus sealing .the gas in the cavity. Screw 25 may then be set against screw 23 to hold the last-named screw in place. Adjusting screws 28 and 29 may be positioned such that the ends thereof are substantially the same distance from central leg 11 and arranged such that a circuit is made between reservoirs 15 and 16 when a preselected amount of movement of the adjusting screws toward each other is provided.

The operating means for the circuit breaker is illustrative and includes a cam 38 having a high point 39, said cam being mounted on a shaft 40 which is driven by appropriate motive means (not shown). The head of adjusting screw 29 may be used as .the cam follower and is caused to follow the cam contour primarily by spring 31 and to some extent by spring 30. When the cam high point 39 engages the cam follower, leg 13 is moved toward leg 11, compressing the mercury in reservoir 16 and causing it to move up passage 20 to passage 42. At the same time, the application of pressure to reservoir 16 also applies a pressure to reservoir 15, causing the mercury in the last-named reservoir to rise up passage 19 and engage the mercury from passage 20 in passage 42, thereby making a circuit between terminals 26 and 27. Pressure is applied to the reservoirs until the ends of screws 28 and 29 engage the central leg portion 11. It will be seen that by making passages 19 and 20 relatively small in diameter a minimum of cam tollowermovement is required to make the circuit.

The circuit through the mercury in the passages and in cavity 21 will be sharply broken as the cam'high point moves off the cam follower. Springs 30 and 31 relieve the pressure on the mercury and return the reservoirs to their original sizes. Thus, the mercury in passage 42 is literally sucked back into the reservoirs. Furthermore, the inert gas in cavity 21, having been placed under pressure by the rising mercury, serves to aid in returning the mercury to its original level in passages 19 and 20. .It will be noted that a sharp breaking point, illustrated by reference numeral 41, is provided. As the mercury is withdrawn past this point the circuit is sharply broken, there being little or no opportunity for arcing across said point.

The embodiment of 'the invention shown in Fig. 3 is somewhat similar to the embodiment described above, the main difference being'in the mounting and adjusting means. For those parts of the circuit breaker which are similar in each embodiment, the same reference numerals are used and a brief description thereof is deemed unnecessary. Referring to Fig. 3, the .three legs which extend from the head portion 14 are illustrated by reference. numeral- s 50, 51 and 52, the central leg 51 being somewhat longer than the legs on each side thereof. A lateral extension 53 is furnished on the side of leg 51 adjacent head 14. This extension is provided with a tapped bore to receive a mounting screw 54 which extends through an aperture in the L-shaped frame member 55 before entering said bore. The frame member also has an adjusting screw 56 extending therethrough, the end of the last-named screw being adapted to engage the free end of leg 51. It will be apparent that movement of leg 51 toward leg 50, under the control of screw 56, will vary the height of the mercury in passage 19.

The base portion of the L-shaped frame member 55 is furnished with a slot 57 and a hole 58. The lower end of leg 56 fits within slot 57 and is adapted to have lateral movement between sides 60' and 61, said sides being used as stops for limiting said movement. A spring 59 is provided in hold 58 and is adapted to resiliently hold leg 50' against side 61.

The operation of the embodiment shown in Fig, 3 is such that the high point of cam 38 engages the head of screw 29 and forces mercury from reservoir 16 into passage 42. At the same time, mercury from reservoir 15 is forced into passage 42, thereby making the circuit. The circuit is broken in the same manner as in Flrg. 1.

From the above-detailed description it will be seen that I have provided a mercury circuit breaker which requires only a small amount or movement to make an electrical circuit. Also, the apparatus exhibits sharp circuit breaking characteristics since the mercury is quickly withdrawn from passage 42 upon termination of the application of pressure to the reservoirs.

It is apparent that operation of the circuit breaker does not require that thecam operate with adjusting screw 29 as the cam follower. Actually, any means of applying pressure to \theiese'rvoirs for compressing the mercury therein and forcing it up into passage 42 may be used.

While there have been-shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claim.

What is-claimed is:

An electric circuit interrupter comprising a body having first and second variable volume reservoir means adapted to have a fluid therein capable of conducting electricity, an electrode in each reservoir means, said body having first and second restricted passage means respectively communicating with said first and second variable volume reservoirs, said first and second restricted passage means extending from the reservoirs with which they are inco'mmunication and convergingat a make and break point, said body having a cavity therein, a third restricted passage means in-c'ommunication with said cavity and said make and break point, said cavity having an inert gas therein, and means for decreasing the volume of said first and second reservoir means to force the fluid therefrom respectively through said first and second restricted passage means to said make and break point and into said third restricted passage means for establishing an electrical circuit between the electrodes in said first and second reservoir means, the inert gas in said cavity being under sufiicient pressure to' urge the fluid out of said third passage means and away from said make and break point back toward said first and second reservoir means to break the electrical circuit between the electrodes in the reservoir means when the volume of each of said first and second reservoir means is increased.

References Cited in the file of this patent UNITED STATES PATENTS Hancock Nov. 30, 1954

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