US2558783A - Switch - Google Patents

Description

Patented July 3, 1951 SWITCH Jean H. Robinson, Jr., United States Navy, and Riley D. Scott, United States Naval Reserve Application August 24, 1945, Serial No. 612,519

14 Claims. (Cl. 200112) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates in general to an electric switch and in particular to a mercuryoil switch Which is adapted to operate in exposed positions and in positions subject to motion and vibration.

In many cases, such as for example on board ships and other moving equipment, it is desired to have a quietly operating electric switch to complete and break electric circuits without undue arcing, which can be controlled from a master switchboard which in turn takes up a minimum of space. The need for such a switch is perhaps most clearly brought out in the construction and operation of small naval vessels such as destroyers, destroyer escorts and submarines.

It is an object of this invention to provide a mercury-oil type of electric switch that is adapted to operate With a minimum of arcing.

It is another object to provide an electric switch that is adapted to be worked by a small-sized switchboard located at a distance from the main switch.

It is an additional object to provide an electromagnetically operated mercury-oil-type electric switch.

It is a further object to provide an electric switch of the mercury type that can be installed and operated independently of position and external motion.

Further objects and advantages of this invention, as well as its construction, arrangement and operation, will be apparent from the following description and claims in connection with the accompanying drawing, in which Fig. 1 is a cross sectional view of a mercury oil switch according to one embodiment of this in- Vention.

Fig. 2 is a diagrammatic view of the switch shown in Fig. l showing the relative location of parts in the open position.

Fig. 3 is a view similar to that of Fig. 2 showing the relative location of parts in the closed position.

In the figures of the drawing, there is shown an electric switch generally designated II contained within an outer casing or container generally designated I2. This container I2 comprises a cylinder I3, a top or cap I4 and a base I5. The container I2 is constructed of a liquid-tight electric insulator, such as for example an insulating ber, an electric-insulating plastic or the like.

Optionally, the cap I4 can be adapted to be screwed on to the top of the cylinder I3, or alternatively it can be integrally fixed thereon.

Near the center of the cylinder I3 are a pair of metallic rings or contacts Iii and I'I mounted Within the cylinder, optionally by being molded therewithin, and having their inner surfaces in line With the inner surface of the cylinder. These rings I6 and I'l are positioned apart a suitable distance to prevent sparking therebetween at the Voltage under which the switch is adapted to operate, and are preferably located near the center of the cylinder I 3. Within the container I2 and adjacent to either end thereof are two double solenoids generally designated I3 and I9. These solenoids are mounted by conventional means such as supports 20. Each solenoid comprises an inner half 2| and 22 and an outer half 23 and 24.

Slidably mounted within the cylinder I3 near its lower end is a piston 25 having a piston rod 26 connected thereto through insulating Washer 26a, the rod 26 extending from the lower portion of the piston and projecting within the lower solenoid I9. On the outer surface of piston 25 and bearing against the inner wall of the cylinder I3 are a plurality of piston rings 21. The piston 25, piston rod 26 and optionally the rings 21 are constructed of a non-magnetic metal such as aluminum, a non-magnetic stainless steel, or the like.

Integrally attached to piston rod 25 is an armature 28 which optionally is a rod of similar cross section to the piston rod 26. This armature is suitably constructed of a highly magnetic material such as for example soft iron or a ferromagnetic alloy.

Similarly, near the upper end of the cylinder I3 is a piston 29 adapted to slide Within cylinder I3, and having a piston rod 30 connected thereto by means of insulating washer 33a and having a piston ring 2l on its outer surface. Optionally, this upper piston 29 is divided into a piston body 3| and a piston face 32. The piston body 3| and the piston rod 39 are suitably constructed of a non-magnetic metal such as for example aluminum or an insulating non-metal, Whereas the piston face 32 is constructed of an electric insulating material such as for example an oil-resisting thermo-setting resin. The piston face 32 can be integrally attached to the piston body 3l or alternatively it can be separated therefrom as shown in Fig. l by an air or oil space 33. When such an air or oil space 33 is provided there can optionally be used a ball check valve 3@ and a valve spring 35 to permit the upward passage of liquid or vapor through the piston 2S). Under normal conditions or" operation this ball check valve can be omitted; however, when the switch is to be used with unusually high voltages and there is danger of electric arcing notwithstandingr the construction and operation oi this switch, it may then be desirable to provide this, valve to permit escape of mercury vapor which is generated during the arcing process.

Integrally attached to the piston rod 3@ and projecting within upper solenoid i6 is an upper armature 3E of similar construction and designito lower armature 2S.

On the inner surface of the-cylinder 13V. be-V tween the upper electrical contact I6 and the lower contact il', is an annular piston wedgeseat- 32a comprising a wedge-shaped ringprojecting from the surface of the cylinder. 32 is adapted to rest against this wedge seat thereby effectively sealing oir" the upper electrical.

contact i5.

Also located on the inner surface of the cylinder are two broad rings 25a and 29a of a metallic substance such as for example aluminum, steel or the like` These rings 25a and 2te` are adapted to .provide a smooth hard .surface to maintain.

The piston face Contact with the sliding piston rings 2l' thereby preventing undue wear of the walls of the cylinder and enabling the piston rings to maintain` a liquid-tight sliding joint with the cylinder walls;

By virtue of the two pistons, 25 and 29, the

cylinder is divided into three chambers: anupper In Figs. 2 and .are shown a diagrammatic Connecting the upper outline of the switch described in connectionwith Fig. 1 indicating the position of parts in the open andclosed state oi the switch.Y In the switch Vas shown in Figs. and 3, the lower ,chamber 3b,

the by-pass tube t@ (not shown), andthe upper chamber iii are substantially lled with oil .oran

oil-likev substance up to oil-level line 35. The

middle chamber 39 of the switch is partly filled.

with'mercury to the level indicatedby the mer-Y cury level line Atthe top of the upper chamf bert?, above the` oil-level line 5, is. asmall quantity oi air or other gas to provide for .expan-l sion or contraction of the contents of the cylinder.

In Fig..2, which shows the open position for the switch, the lower armature 28 is positioned within the outer hah 2t of thelowerfsolenoidiil and accordingly the lower piston 25 is retracted toward the bottom of the cylinder. The upper armature 3S, on the other hand, is positioned withinv theinner half 2i of theupper solenoid i8 and accordingly the upper piston 3l is positioned .well withinthe cylinder with the lower space of the piston face 3E below the upper electrical Contact it and resting against. piston wedgeY d seat 32a (Fig. l), thereby sealing oli the upper electrical contact i5 from any contact with the mercury contained in the mercury chamber 39.

In Fig. 3, which shows the closed position of the switch, the lower armature 28 is positioned within the inner hah" 22 of the lower solenoid I9, while the upper armature 3b is positioned within the outer half 23 of the upper solenoid i8, thereby causing the upper piston to be raised above the upper electrical contact l 6 and causing the lower piston 25 to be correspondingly raised almost to the level of the lower electrical contact Il. Thus, in the closed position of the switch,"both electrical contacts iii and i7 are covered by the mercury contained in the mercury chamber 39 and thereby are electrically joined.

In the use and operation of this electrical switch the various `chambers are filled with oil and mercury-as indicated in the drawings and hereinbefore described, and the switch is installed in a suitable location. The inner half 22 of lower solenoid it is electrically joined to the outer half 23 of upper solenoid i3 as by conductor 5D, and, likewise, the outer half 2t of lower solenoid I9 is electrically joined to the inner half 2l of upper this switch is turned to the on position half- v solenoids 22 and 23 are energized and when the switch is turned to the cli position half-sole'- noids 2i and 2li are energized. Thus the opera?l tion oi a low-voltage switchen a remotely located switchboard controls the operation of vthe main switch li.

When the externally located control switch' is turned to the Von. position, pistons 25 and 29 are caused to rise within the cylinder Vi3 thereby bringing theY mercury in contact with both of the electrical contacts it and l?, Simultanecuslyoil passes from upper chamber 3l. to lower chamber 33 through by-pass .it to permit .this movement of the pistons. When the control switch is moved to the.o position this piston and liquid motion is reversed thereby breaking the contact. The presence of the layer offoil on top of the mercury in the mercury chamber causes the electrical circuit to be broken with a minimum of arcing thereby preventing the formation of undue quantities of mercury Vapor and preventing .undue corrosion of the electrical contacts.,

Although this switch has been described as` being ina-vertical positiolnit will be seen that the .upper piston in its closed position completelyseals off the upper Aelectrical Contact I6 Jfrom the mercury chamber, and therefore this switch can be installed in a verticalv or horizontal position and can be. subjected to vibration. or` rocking motion without causing accidental electrical contact.

In repairing and maintaining this switch the following dismantling procedure is used: The

screw plug 43 is removed and drainll .is then opened permitting the oil to drain from the lower chamber t3 and the by-pass tube di?l and to drain partially from the upper chamber 3l. The

cap l is then unscrewed permittingaccess to the mally associatedtherewith. Forexample, theA undue arcing normally associated With mercury switches has been eliminated, and possibly of.

even greater importance, the new switch is independent of position or external motion. The advantage of compactness and convenience of size of the new switch is still further improved by the fact that the switch is adapted to be electrically operated' by remote control, permitting the mounting of numerous small master switches on a convenient switchboard maintained in small and crowded quarters.

Modifications and changes can be made in this invention without departing from the spirit and scope thereof as set forth in the appended claims.

For example, the lower piston 25 can be electrically activated to become one of the electric contacts, operationally replacing contact Il. Likewise various other conventional and obvious changes in the structure and operation can be made.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

l. A mercury-oil electric switch comprising an insulating cylindrical container, a pair of magnetically-operated pistons mounted therein and adapted to propel within the cylinder in mutually opposed directions a body of mercury having a body of oil on its upper surface, one of said pistons having an insulating part adjacent said body of mercury, and a plurality of electric contacts mounted within said cylinder, said insulating part operating to insulate at least one of said contacts from said body of mercury as the latter is moved in a first direction within the container by said one piston.

2. The switch as in claim 1, wherein said one contact is adapted to be electrically joined to said body of mercury as the latter is oppositely moved by the other piston.

3. A mercury-oil electric switch comprising an insulating cylindrical container having two electric contacts mounted within a common straightline section of said container and insulated one from the other, a pair of opposing pistons mounted within said straight-line section and magnetically operated from either end thereof, a body of mercury and a body of oil positioned between said pistons and adapted to be propelled within said container so that the body ofniercury is caused to make and break electrical connection with one of said electric contacts while maintaining electrical connection with the other of said electrical contacts.

4. A mercury-type electric switch comprising an insulating cylinder, two electric contacts internally mounted within said cylinder, a lower piston mounted within the cylinder near the lower end of said cylinder and adapted to be mae'- netically propelled and retracted by a solenoid mounted from the lower end of said cylinder, an electrically insulating upper piston mounted within the cylinder and near the upper end thereof and adapted to be magnetically propelled and retracted by a solenoid mounted from the upper end of the cylinder so as to cover and uncover one and only one of said two electrical contacts, a body of mercury and a body of oil positioned between said pistons and adapted to cover and uncover one of said electric contacts as the pistons are propelled and retracted, while maintaining an electrical connection with the other of said electric contacts, and a by-pass tube connecting the portions of the cylinder behind the upper and lower pistons'respectively and permitting fluid flow therebetween.

5. A mercury-oil switch comprising a cylindrical container, a plurality of electromagneticallyoperated pistons mounted therein and adapted for simultaneous operation for propelling in mutually opposed directions a body of mercury contained within the cylinder, and a plurality of electric contacts mounted within said cylinder, at least one of said contacts being positioned to be electrically connected tov said body of mercury as the latter is moved within the container by one or" said pistons and disconnected therefrom as the mercury is moved by another of said pistons.

6. A mercury-oil switch comprising a cylindrical container, a pair of spaced electromagnetically operated pistons mounted therein the adjacent faces of said pistons dening, with the side wall of said container, a substantially closed space, a body of mercury within said space and adapted for constrained movement with said pistons, and a plurality of electric contacts mounted ush with the inner wall of said cylinder, at least one of said contacts being positioned to be electrically connected to said body of mercury as it is moved within the container.

7. The switch claimed in claim 6 further comprising means on said pistons and cooperable with said contacts for ensuring a duid-tight junction between said pistons and contacts.

8. A switch comprising a container having at least two electric contacts mounted therein and insulatingly spaced one from the other, a pair of pistons mounted for movement axially of said container, said pistons being dimensioned to fit snugly within said cylinder and adapted to be magnetically operated from opposite ends thereof, a body of mercury disposed between said pistons and adapted to be propelled within said container by said pistons, whereby the body of mercury may be caused to make and break electrical connection with one of said contacts while maintaining constant electrical connection with the other of said contacts.

9. The switch defined in claim 8 further characterized by stop means in the path of one of said pistons for limiting the amount of travel of said one piston toward said other electrical contact.

10. The switch defined in claim 8 further characterized by electromagnetic means within said container and adapted to be energized for conjointly moving said pair of pistons in a unitary direction, and coolant means surrounding said electromagnetic means.

11. An electric switch comprising a tubular container, fluid contact means in said container, a pair of annular contacts mounted flush with the inner wall of said container, piston means defining with said wall an enclosure for said fluid contact means, and means for moving said enclosed fluid contact means selectively to make and break electrical connection between said contacts.

12. An invertible mercury switch, comprising a tubular container, mercury in said container, contacts mounted in the wall of said container, and piston means defining with the container wall an enclosure for conning said mercury, whereby the latter may be moved to make and break electrical connection between said contacts independently of the disposition of said container.

13. The switch as in claim 12, wherein said pist'o'nf meams.comprises. a :pair of spacedplungerA f members edjaeent the freesurfaceszof saidmerf' cury;y and;electromagnetc-:kmeans :for :each said member for moving the latter in unison.

14h@ The v:fswitchras @in;.c1am "12,A whereinv said pstonemeans:` comprises spaced 'movable plunger.

members With the mercury disposed'therebetweeny andzmeans 'dening Laivent infone of saidfmembers" REFERENGES CITED The following #references f are "of record"- rin the Nalm'e'f Date' Gr'e'eneld et falf July' 4,1 1882 B'own Nov.' 17, 1885 Lemp AM Febfll, 1830' Ct1er-= Apr. 19, 1910 FREIGNPATENTS.

Country' Date Germany? Oct. 29,`r 1914

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