US3502831A - Force responsive switch - Google Patents

Description

March 24, 1970 L." HL M ROSK EY 3,502,831

FOR-CE RESEONSIVE swmcn 2 Sheets-Sheet 1 Filed Feb. 5, 1969 y w /vm sol/l wm W cW M Mmw m WWW M NM WM 6W L B March 24, 1970 -L..H'. MRO-SKEY FORCE RESPONSIVE SWITCH 2 Sheets-Sheet 2 F iled Feb. :5,- 1969 INVENTOR WHANNMMANI6AL United States Patent 3,502,831 FORCE RESPONSIVE SWITCH Leonard H. McRoskey, 420 Loring Ave., Los Angeles, Calif. 90024 Filed Feb. 3, 1969, Ser. No. 796,041 Int. Cl. H01h 35/02, 35/14 US. Cl. 20061.49 8 Claims ABSTRACT OF THE DISCLOSURE A switch which responds to the force of gravity, inertia,

vibration or other forces having a ring contact and a BACKGROUND OF THE INVENTION Switches of this type for closing or opening electrical circuits are commonly referred to as trembler switches. In the prior art there has been employed a cantilever mounted spring with a weight on its outer end, the spring being of, rugged construction and being sensitive to vibration to move this spring element or anode, this movement rendering the tube conductive. Such a vibration sensitive diode is disclosed in the patent to Bianchi, et al., No. 2,999,179, dated Sept. 5, 1961,'the object of this invention being to avoid actual contact of the anode and cathode and thus eliminate the disadvantages of switches having elements which make actual contact.

Such devices have in the main been quite large and often too large for mounting in smallconfined spaces. The switch of the present invention is adapted for use as a switching means closing an electric circuit in response .to a force, such as gravity, inertia, centrifugal, or vibration producing forces. Applicant is also familiarwith the United States Letters Patent No. 2,996,586 for a magnetic trembler switch which has a body of the order of 1 inch in length in which a rod between a pair of magnets is supported by the magnets in spaced relation to annular contact members adjacent to the ends of the rods. A force responsive switch designed to avoid the disadvantages of the prior art and one which has proven to be extremely successful in actual practice is disclosed in the copending application of Carley, McRoskey, and Parsons for Switch, Ser. No. 679,098, filed Oct. 30, 1967.

SUMMARY OF THE INVENTION The present invention relates to a unique force responsive switch which is designed to avoid manufacturing difficulties and to provide a sturdy and reliable construction.

The switch of my present invention permits the precise fixturing of parts during the manufacturing process thereby eliminating the requirement to run every unit through an exhaustive test series as would be required in the prior art. Automatic production is permissible as to the base and envelope because they may be precisely of the same configuration and tolerance with respect to all parts and the base and envelope elements are fitted together exactly the same each time.

It is an object of the present invention to provide a force responsive switch in which the shell is formed of conductive material and comprises a ring contact and in which there is a pendulous contact positioned within the envelope or shell, which consists of a closely wound unweighted helix which when subjected to a force of sufficient magnitude will move into engagement with the ring contact and close an electric circuit. These two contacts, namely the shell which provides the ring contact and the pendulous contact, are insulated from each other.

3,502,831 Patented Mar. 24, 1970 It is a further object of the invention to provide an arrangement in which the central electrode is heat in- BRIEF DESCRIPTION OF THE DRAWINGS Referring to the accompanying drawings which are for illustrative purposes only:

FIG. 1 is an enlarged longitudinal section of oneform of switch, incorporating the features of the invention;

FIG. 2 is a cross-sectional view taken on the line 22 of FIG. 1;

FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG. 1;

FIG. 4 is an enlarged longitudinal sectional view of a switch showing an alternative form with an enlarged base;

FIG. 5 is a longitudinal sectional view showing the manner in which the swaging of the envelope may be employed to change the diameter of the ring contact;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5;

FIG. 7 is a longitudinal sectional view showing an alternative method of attaching a lead wire to the envelope;

FIG. 8 is a sectional view through a form of my invention employing a different design of base;

' FIG. 9 is a sectional view taken along the line 99 of FIG. 8; and

FIG. 10 is, a longitudinal sectional view taken through another form of my invention showing an alternative -method of closing an end of the envelope and providing DESCRIPTION OF PREFERRED EMBODIMENTS Referring more specifically to the drawings and particularly drawings FIGS. 1-3 inclusive, my invention provides an envelope 20 which is made from an electrically conductive material such as Kovar which is an alloy composed of 29% nickel, 17% cobalt, .2% manganese and 53.8% iron; but could be made from brass, alu minum or alloys thereof. The envelope 20 has a cylindrical body 21 which is closed at one end by an end plate 22. In the form of the invention herein disclosed the outside diameter of the envelope is approximately .160 inch with a wall thickness of approximately .015 inch.

Opposite the closed end 22 is an open end of the envelope 20 having an end wall 23. The numeral 24 represents a base which has a cup or receptacle 25 which is made from Kovar. The receptacle 25 has a sleeve or cylindrical wall 26 which fits into the cylindrical end of the envelope 20 and has an end flange 27 which engages the end face 23 of the envelope 20. The receptacle 25 has an end wall 28 at its inner end provided with a concentric opening 29. When the parts are assembled, the envelope and receptable form a closed chamber 30 which is evacuated of its air and is filled with an inert gas such as argon. The envelope and base are secured together such as by welding at the joint 31 which is formed where the flange 27 engages the end wall 23.

The receptacle or cup 25 is filled with an insulation body 33 which may be formed of epoxy or other plastic or glass. Extending into the receptacle 25 and in engagement with its cylindrical wall 26 thereof is an electrode 34 to which a circuit wire may be connected in order that the receptacle 25 and envelope 20 are connected to one side of an electric circuit. The insulation material when molded into place secures the electrode 34 in place. There is also a central or concentric electrode 36 which is made from an alloy such as Dumet which is an alloy consisting of 54% iron, 46% nickel and copper plated. The electrode 36 is approximately .016 inch in diameter, this same material having the same diameter as employed in the electrode 34. The electrode 36 is positioned concentric to the axis of the envelope 20 and the axis of the receptacle 25. The electrode extends from the exterior of the switch through the insulation body and centrally through the opening 29 in the end wall 28, the opening 29 being larger than the electrode 36 so that these parts are not in electrical contact with each other.

When forming the subassembly consisting of the receptacle, the body of insulation and the two electrodes, these parts are held accurately in place by a suitable jig or fixture and the insulation is then poured into place and when it hardens the subassembly has the parts accurately secured together.

Applied to the inside face of the end wall 28 is an insulation disc 38 which along with the body 33 has heat insulation qualities. This is for the purpose of preventing heat occasioned by welding of the envelope and receptacle, from reaching the inner end of the electrode 36.

Secured to the inner end of the central electrode 36 is a movable vibration sensitive pendulous contact such as generally indicated at 40, this contact being in the form of a helix or coiled spring in which the turns are closely wound with respect to each other. For simplification the drawings show the turns of the spring out of contact but in actual practice the coil is a closely wound coil. The contact is made from tungsten wire and is approximately .003 inch in diameter and the internal diameter of the helix is approximately .016 inch. The lower end 41 of the helix is wound so that its inner diameter is substantially that of the electrode 36. These two parts are secured together by a weld 42 which is positioned away from the end of the pendulous portion of the spring 40 in order that the heat from this spot weld will not damage or draw the temper of the helix.

The pendulous contact 40 rests along the longitudinal axis of the envelope 20 when the trembler switch is mounted in an upright position as shown in FIG. 1. The sectional view FIG. 2 shows the contact 40 in a central position. The cylindrical body 20 constitutes a ring contact which may be engaged by the pendulous contact 40 when it moves in any radial direction. With the switch in this vertical position, the parts are designed so that the pendulous contact 40 will be deflected when the force acting on the switch is two Gs plus or minus three tenths. If the switch is placed in a horizontal position, the pendulous contact will bend downwardly so that it is closer to the lower portion of the wall of the cylindrical body and therefore contact will be made at a lower force such as for example as one G.

The amount of force required to close the contacts may be varied by changing the diameter of the envelope 20 or the diameter of the pendulous contact 40. Also the closing force may be varied by making a change in the diameter of the wire from which the pendulous contact 40 is made.

In the operation of my invention, the electrodes 34 and 36 are connected in an electric circuit which electric circuit is connected to any device Which is to be actuated. Whenever forces reach a predetermined amount, contact 40 will engage the ring contact or envelope 20 closing the circuit and causing an operation.

In the form of the invention shown in FIG. 4, the diameter of the envelope 20 is .160 inch. In this arrangement the end portion or base 50 is in the form of an enlargement or bell having a bottom wall which is engaged by the wall 28 of the receptacle 25.

In FIGS. 5 and 6 there is shown an alternative construction for obtaining the diameter of the ring contact. In this form of my invention the cylindrical wall 21 of the envelope 20 is swaged as indicated at 60 to form an annular contact ring 61 which is of a diameter of .160 inch. This swage '60 may be of different depths depending upon the desired distance which is required between the ring contact 61 and the pendulous contact 40.

FIG. 7 shows the form of the invention in which the electrode 34 is removed and in its place is an electrode 70 secured to the top end of the envelope 20. In this arrangement, the wires of the circuit are connected to opposite ends of the switch.

In FIG. 8 the base is in the form of a metal body which may be made of Kovar metal and which is separated from the envelope by means of an insulation sleeve 82 having a flange 84 positioned between a flange of the body 80 and the end wall 23 of the envelope. The electrode 36 may be formed integral with the body 80 as indicated at 36a and there may be an inner electrode 36b which is formed concentric to the longitudinal axis and which supports the pendulous contact 40'.

In FIG. 10 the enevlope 20 is in the form .of a tube and does not have an integral end 22. The upper end of the envelope sleeve is closed by a Kovar plug which has an electrode 102 connected to it. In this form of my invention, the electrodes 36a and 102 are in alignmentwith each other at the opposite ends of the switch.

I claim:

1. A force responsive switch comprising:

(a) a conductive envelope having an annular portion providing a contact;

(b) a flexible pendulous contact formed of a tightly wound helix extending longitudinally with respect to said envelope and having a portion within the annular portion of said envelope, soid pendulous contact being adapted to be moved by a predetermined force so as to engage said annular portion;

(c) a base closing one end of said envelope and including insulation means; I

(d) an electrode insulated from said envelope by said insulation means and connected to said base; said electrode supporting said pendulous contact at one of its ends'and extending to the exterior of said envelope; and

(e) means whereby said pendulous contact completes an electric circuit only upon engagement of the helix portion with said annular portion.

2. A switch as defined in claim 1 in which said envelope has a cylindrical end and in which said base includesa cylindrical shell which fits in said cylindrical end anda body of insulation material positioned within said cylindrical shell for supporting said electrode concentric with said envelope and out of electrical contact with said shell and said envelope.

3. A switch as defined in claim 1 in which said conductive envelope is cylindrical and has an area of reduced diameter which forms a ring contact and in which the pendulous contact extends through said reduced area.

4. A switch as defined in claim 1 in which said base includes a body of conductive material positioned in the end of said envelope and supporting said electrode, said insulation means comprising an insulation wall between said base body and said envelope to maintain these parts out of electrical contact.

5. A switch as defined in claim 4 in which there is; a metal plug in the opposite end of said envelope to said base, said metal plug having an electrode: connected thereto on the exterior of said envelope. H

6. A switch as defined in claim 2 in which said envelope is cylindrical and is provided with an enlarged cylindrical end an in which said base includes a metal cup having a cylindrical wall fitting in said enlarged cylindrical, end and in which said metal cup has an end wall with an opening in it through which said electrode extends, said body of insulation supporting said electrode in an axial 5 6 position and out of electrical contact with any metal part References Cited of said cup or said envelope.

7. A switch as defined in claim 6 in which there is a UNITED STATES PATENTS heat insulation element applied to the inner face of the 2,407,073 9/1946 GOTFOH 200-6151 end wall of Said metal cup 2,983,800 5/1961 Rablnow 2006l.45 8. A switch as defined in claim 6 in which there is a 5 3,415,960 12/1968 Koumeyer second electrode extending into said cup in contact with the cylindrical wall thereof and held in place by said ROBERT SCHAEFER Pnmary Exammer insulation material. M. GINSBURG, Assistant Examiner

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