US3360625A

US3360625A - Fluid switching device

Info

Publication number: US3360625A
Application number: US578597A
Authority: US
Inventors: Robert W Nickelson
Original assignee: Beltone Electronics Corp
Current assignee: Beltone Electronics Corp
Priority date: 1966-09-12
Filing date: 1966-09-12
Publication date: 1967-12-26
Anticipated expiration: 1984-12-26

Description

6 R. w. NICKELSON 3,360,625

FLUID SWITCHING DEVICE Filed Sept; 12, 1966 5 Sheets-Sheet 1 Fl I T FIGZ INVENTOR ROBERT w. NICKELSON BY J'Eumm ATTORNEYS Dec. 26, 1967 I R. w. NICKELSON 3,360,625

FLUID SWITCHING DEVICE Filed Sept. 12, 1966 5 Sheets-Sheet 2 54 a+ 54 F167 a 5| FIGS? I I I 55 ll 5| /6O l w 56 1 65 56- ,eo :5: fi m 62 74 73 63 734 If i I 63 77 52 77 J52 i 76 If? 76 INVENTOR ROBERT W. NICKELSON BY gm AM/mm fm ATTORNEYS Dec. 26, 1967 R. w. NICKELSON 3,360,625

FLUID SWITCHING DEVICE Filed Sept. 12, 1966 5 Sheets-Sheet 5 FlGIO FIGLIII 84 0 INVENTOR ROBERT w. NICKELSON BY 1 Mi ATTORNEYS United States Patent 3,360,625 FLUID SWITCHING DEVICE Robert W. Nickelson, Elk Grove Village, Ill., assignor to Beltone Electronics Corporation, a corporation of Illinois Filed Sept. 12, 1966, Ser. No. 578,597 6 Claims. (Cl. 200--152) 7 ABSTRACT OF THE DISCLOSURE Anelectrical switch having a fluid switching element mounted within a molded plastic housing. The switching element comprises a pair of spaced-apart contacts positioned inside an elastically deformable container which is partially filled with an electrically conductive, nonwetting fluid (such as mercury). A pair of actuating membersarefastened on opposite sides of the deformable container such that, when the members are pressed together, the fluid passageway through the container is constricted, thereby separating the fluid into spaced-apart physical segments and opening the circuit path through the fluid. When the actuating members are moved apart, the passageway is forcefully opened-to again create a fluid circuit path. Oneof the actuating members may be spring loaded to hold the switchin a normally open or normally closed position.- Y

Background and summary of the invention This invention relates to an improved electrical switchingarrangement wherein electrical connections are established through an electrically conductive fluid such as mercury.

U.S. Patent No. 3,177,327 which issued to Erwin M. Weiss on Apr. 6, 1965, discloses a fluid switch construction employing a sealed, deformable container partially filled with an electrically conductive, non-wetting fluid. Switching is accomplished by deforming the vessel to constrict a fluid-holding passage between the terminals of the switch. At the point of constriction, the fluid physically separates to open the electrical circuit path. The operation of this switch is based upon the interaction between surface tension forces and the internal pressure forces within the deformable container.

The fluid switch disclosed in the Weiss patent possesses numerous significant advantages. In particular, undesirable contact openings and closures due to contact bounce (which results from the elastic collision which takes place between the contacts in a mechanical switching device) are eliminated. Furthermore, the sealed fluid switch described in the above patent does not suffer from the eifects of contact deterioration-or the formation of contaminating films between the contacts.

After extended use, such fluid switches are subject to sticking; that is, the interior surfaces of the fluid-holding envelope, when pressed together as the envelope is constricte'd, may adhere to one another, maintaining an open condition between the electrical terminals of the switch even after the constricting force is removed.

It is accordingly a first object of the present invention to eliminate sticking in a fluid switch.

It is a more general object of the present invention to provide a new and improved fluid switch construction which is simple and inexpensive, yet which provides improved performance and great durability.

In a piincipal aspect, the present invention takes the form of a fluid switch including a pair of spaced-apart contact terminals and an elastically deformable, hollow envelope which defines. a passageway between these terminals. The passageway is at least partially filled with an electrically conductive fluid which is non-wetting with respect to the interior surface of the envelope. In accordance with a feature of the invention, first and second actuating members are fastened to the envelope on opposing sides of the passageway and means are employed for moving at least one of these members relative to the other to constrict the passageway when the members are spaced closely together in order to separate the fluid into noncontacting physical segments. When the members are moved apart, the passageway is forcefully opened, uniting the fluid segments, and creating a low impedance electrical connection through the fluid between the contact terminals. Because the actuating members are rigidly affixed to the envelope, the force which is applied to separate the actuating members serves to break the adhesion between the interior surfaces of the passage. In a preferred, normally closed embodiment of the invention,

I the envelope is mounted, a portion of the surface of the envelope being adhesively aifixed to the interior surface of the housing such that this portion of the housing forms one of the actuating members. A control, extending through the housing, isthen employed for moving the second actuating member, which is attached to the envelope at a point opposite from the point where the housingis aflixed.

Brief description of the drawings These and other objects, features and advantages of the present invention may be more clearly understood through a consideration ofthe following detailed description. In the course of this description, reference will frequently be made to the attached drawings in which:

FIGURE 1 is a side elevational view taken partially in cross-section and illustrating the operation of the invention;

FIGURE 2 is a side elevational view of the switch shown in FIGURE 1 with the interior passageway constricted;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 1;

FIGURE 4 is a side cross-sectional view taken along the line 4-4 of FIGURE 2;

FIGURE 5 is a perspective view of a preferred embodiment of the invention shown with a portion of the housing cover broken away to show the interior details of the switch construction;

FIGURE 6 is a side cross-sectional View of the switch shown in perspective in FIGURE 5 in the normally closed position;

FIGURE 7 is an end cross-sectional view of the switch shown taken along the line 7-7 of FIGURE 6;

FIGURE 8 is a side cross-sectional view of the switch shown in perspective in FIGURE 5 in the normally open position;

FIGURE 9 is an end cross-sectional view of the switch taken along the line 99 of FIGURE 8;

FIGURE 10 is a side cross-sectional view of a second embodiment of the invention shown in its normally closed position;

FIGURE 11 is an end cross-sectional view taken along the line II-l1 of FIGURE 10;

1 FIGURE 12 is a side, cross-sectional view of the second position; and,

FIGURE 13 is an end, cross-sectional view taken along the line 13-.13 of FIGURE 12.

Description of the preferred embodiments The operation of the invention is illustrated by FIG- URES 1 through 4 of the drawings. FIGURE 1 shows an elastically deformable, tubular envelope, shown generally at 21, which includes an interior, hollow region at least partially filled with an electrically conductive, non-wetting fluid (such as mercury) illustrated at 23. The ends of the tubular envelope are sealed by the metallic end caps 25 and 27. The envelope 21 includes upper and lower projecti-

ons

31 and 33 respectively. As best seen in FIGURES 3 and 4, an actuating wire 35 passes through the projection 31 and extends outwardly on both sides of the envelope 21. The lower projection 33 is cemented into a notch 37 cut into the base surface 40.

Coil springs

41 and 42 are shown projecting from the ends of actuating wire 35 to the base surface 40.

The

springs

41 and 42 hold the actuating wire 35 in spaced relation from the base surface 40 to complete an electrical connection between the metallic end caps 25 and 27 through the fluid 23. This circuit path may be opened by depressing the actuating wire 35 to constrict the passageway within envelope 21, thereby separating the liquid 23 into spaced apart

physical sections

23a and 23b as shown in FIGURE 2. As depicted by FIGURE 4, the actuating wire 31 insures that the passageway within envelope 21 is constricted across its entire width. The

compressed springs

41 and 42 insure that the circuit connection will be again closed (that is, the constriction in the fluid passageway will be removed) when the downwardly directed actuating force is removed from the actuating wire 31. Since the opposing sides of the envelope 21 are aflixed respectively to the actuating wire 31 and to the base surface 40, any tendency of the inner surfaces of the envelope to adhere together is overcome.

A preferred embodiment of the invention is shown in the perspective view of FIGURE 5, an exterior portion of the switch being cut away to illustrate its inner details. The embodiment shown in FIGURE includes a base section, indicated generally at 52, upon which a cover 51 is mounted. A push button 54 extends upwardly through an opening 55 in cover 51. The bottom surface of push button 54 bears against an actuating wire, indicated generally at 60, which passes through an upwardly projecting portion 62 of a fluid-holding envelope 63. The ends of the actuating wire 60 nest within a spring member 65 which serves to hold wire 60 in an upwardly raised position. Each end of the fluid-holding envelope 63 is terminated by a metallic end cap of the type shown generally at 67 in FIGURE 5 which includes an outwardly extending terminal stud 68 which is welded to a switch contact, one of which is shown generally at 70. Contact 71 forms the remaining terminal for this normally closed switch.

The switch shown in FIGURE 5 is operated by depressing the button 54 which moves the wire actuator 60 downward, constricting the fluid passageway within the envelope 63, separating the conductive fluid therein into two physical segments, and opening the switch. When pressure is removed from button 54, the shaped metal spring 65 presses upward on the actuator 60 to again close the circuit path through the fluid.

The details of the switch shown in prospective in FIG- URE 5 are shown more clearly in the cross-sectional views of FIGURES 6 through 9. The base section 52 includes a pair of longitudinal pedestals 73 and 74 (best seen in FIG- URES 7 and 9) upon which the spring 65 rests. The

longitudinal pedestals

73 and 75 also serve to prevent motion of the cover 51 with respect to the base 52 after the two have been joined.

A projection 75 extends downwardly from the undersurface of envelope 63 and, as seen in FIGURES 7 and 9,

is sandwiched between a pair of raised

ridges

76 and 77. The projection 75 is thus cemented to base section 52 such that, as the actuating wire 60 is urged upwardly by spring 65, any adhesion which may exist between the abutting interior surfaces of envelope 63 is broken.

FIGURES 10 through 13 of the drawings show a normally open fluid switch which embodies the principles of the invention. As shown in FIGURE 10, theswitch comprises a base section indicated generally at 81, a cover shown generally at 82, and includes a pushbutton shown at 84. The pushbutton 84 passes through a circular opening and a bezel 86 which is afiixed to the upper surface of the cover 82.

The switch shown in FIGURES 10 through 13 includes a fluid switch cartridge of the type discussed in conjunction with FIGURES 1 through 9 which includes a deformable, elastic envelope indicated generally at 88, a pair of

metallic end caps

89 and 90 and centrally located upper and

lower projections

91 and 92. An actuating Wire 94 extends through the lower projection 92 and nests Within a metal shaped spring 96. A pair of

terminal contacts

97 and 98 extend downwardly through the base section 81 and are welded to the

metallic end caps

90 and 89 respectively.

As best seen in FIGURES 11 and 13, the button 84 includes a bifurcated bottom section comprising the downwardly extending

arms

101 and 102. The

arms

101 and 102 extend through

openings

103 and 104 respectively in the cover 82 and engage with the wire actuator 94. The upper projection 91 on the envelope 88 is cemented into a notch 107 defined between a pair of projections 111 and 112 which extend downwardly from the cover 82. The base section 81 includes a notch 114 centrally located on its inside surface to permit downward movement of the wire holding projections 92 on envelope 88.

With no pressure applied to the button 84, the spring 96 bears upwardly on the actuating wire 94, constricting the fluid passage within envelope 91 and forcing the button 84 upward. In this condition, the fluid within the envelope 88 is broken into two separate physical segments preventing current flow between the terminal 97 and 98.

When the button 84 is depressed, however, the

arms

101 and 102 bear downward on the Wire actuator 94, re-

moving the constriction from the tubular envelope 88 to. create a low impedance electrical connection between the

terminals

97 and 98.

It is to be understood that the embodiments of the invention which have been described are merely illustrative of application of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.

What is claimed is:

1. In combination,

a pair of spaced apart contact terminals,

an elastically deformable, hollow envelope defining a passageway between said terminals, said passageway being at least partially filled with an electrically conductive fluid which is non-wetting with respect to the interior surface of said envelope,

first and second actuating members fastened to said envelope on opposing sides of said passageway,

and means for moving at least one of said members relative to the other of said members between first and second positions, said members in said first position being spaced closely together to constrict said passageway to separate said fluid into non-contacting physical segments and said members in said second position being spaced apart to open said passageway to create a low impedance electrical connection through said fluid between said first and second terminals.

2. A combination as set forth in claim 1 including spring means for normally holding said members in said first position.

3. A combination as set forth in claim 1 including spring means for normally holding said members in said second position.

4. A combination as set forth in claim 1 including a housing for said envelope and wherein said first actuating member constitutes a portion of said housing.

5. A combination as set forth in claim 4 including a control extending through said housing for moving said second member.

6. A combination as set forth in claim 4 wherein a portion of the surface of said envelope is adhesively aflixed to a portion of the exterior surface of said housing.

5 References Cited UNITED STATES PATENTS 3,177,327 4/1965 Weiss 200-152 ROBERT K. SCHAEFER, Primary Examiner. 10 H. HOHAUSER, Assistant Examiner.

Claims

1. IN COMBINATION, A PAIR OF SPACED APART CONTACT TERMINALS, AN ELASTICALLY DEFORMABLE, HOLLOW ENVELOPE DEFINING A PASSAGEWAY BETWEEN SAID TERMINALS, SAID PASSAGEWAY BEING AT LEAST PARTIALLY FILLED WITH AN ELECTRICALLY CONDUCTIVE FLUID WHICH IS NON-WETTING WITH RESPECT TO THE INTERIOR SURFACE OF SAID ENVELOPE, FIRST AND SECOND ACTUATING MEMBERS FASTENED TO SAID ENVELOPE ON OPPOSING SIDES OF SAID PASSAGEWAY, AND MEANS FOR MOVING AT LEAST ONE OF SAID MEMBERS RELATIVE TO THE OTHER OF SAID MEMBERS BETWEEN FIRST AND SECOND POSITIONS, SAID MEMBERS IN SAID FIRST POSITION BEING SPACED CLOSELY TOGETHER TO CONSTRICT SAID PASSAGEWAY TO SEPARATE SAID FLUID INTO NON-CONTACTING