Disturbance Sensitive Switch

Abstract

A disturbance sensitive device comprising an electrical switch having resilient means for supporting a movable contact member in normally open relationship with a stationary contact member, and structured to provide prolonged closure when the device is disturbed. A further improvement includes a second resilient means which is carried on the movable contact member for reducing the gap between the contacting members and increasing the closure time interval.

Description

BACKGROUND OF THE INVENTION

This invention is related, generally, to control devices and is concerned, more particularly, with a sensitive spring-type electrical switch having a prolonged closure time when mechanically disturbed.

One type of disturbance responsive device comprises a motion sensitive, electrical switch which is generally maintained in the "open" position and, when disturbed, closes to complete an associated electrical circuit. Usually, the circuit includes a source of electrical energy, such as a battery, for example; and the resulting flow of electrical current through the switch is an indication that the switch has been disturbed by motion, physical shock, vibration or the like. This flow of current may energize a simple-indicating device, such as an alarm, for example, in the circuit associated with the switch; or it may actuate more sophisticated telemetry equipment, such as recording devices, for example, in a connecting auxiliary circuit. Typically, disturbance sensitive switches may be attached to parts of machinery to indicate the presence of vibration when a malfunction occurs or a change in position of the switch support when movement thereof occurs. However, these sensitive electrical devices also are used in burglar alarm systems or other protective apparatus of that nature to sound an alarm.

A disturbance switch basically comprises a housing having therein a movable conductive member which is adapted to engage a stationary conductive member affixed to the housing. Numerous prior art switches of this type utilize a pivotally supported pendulum as the movable conductive member. In some instances, the pendulum is caused to oscillate and thereby engage the stationary conductive member. In other instances, the switch housing rotates around the free-hanging pendulum thereby bringing the affixed conductive member into contact with the pendulum. In each instance, however, this type of disturbance switch is dependent upon the force of gravity for its proper operation. Thus, if a disturbance switch of the described type is inverted, it will not function as a switch at all. This limitation on the use of disturbance switches of the pendulum type is a serious disadvantage when a plurality of disturbance switches are placed at random over a wide area. Situations of this nature require disturbance sensitive switches which are not dependent on orientation in order to operate properly.

Some types of disturbance switches shown in the prior art have movable conductive members which strike stationary conductive members and rebound, thereby closing associated electrical circuits only momentarily. The resulting low value of current flow through a switch of this type may be adequate for activating a simple indicating device, such as a flashing light, for example. However, more complex telemetry devices require a stronger flow of current through the switch and, therefore, a longer closure time interval. Consequently, some disturbance switches of the prior art are provided with mechanical latching means for locking a movable conductive member into steady-state engagement with a stationary conductive member after contact is made. However, switches of the mechanical latching type, generally, require manual resetting in order to return the movable member to its initial operating condition. Consequently, there is a definite need for a disturbance switch having a prolonged closure time interval and which returns, automatically, to its initial operation condition when the closure interval is completed.

SUMMARY OF THE INVENTION

Accordingly, this invention provides a disturbance sensitive switch comprising an elongated stationary conductor disposed in spaced coaxial relationship with a conductive mass which is movably supported by resilient means. The resilient supporting means includes axial and transverse resilient components, relative to the stationary conductor, which components counteract the force of gravity acting on the conductive mass, regardless of the orientation of the switch. Thus, in the static state, the axial and transverse components of the resilient supporting means hold the conductive mass in balanced spaced relationship with the stationary conductor, thereby maintaining the switch in a normally "open" position.

In operation, the slightest disturbance will jar the conductive mass out of its balanced equilibrium condition and cause it to move transversely with respect to the stationary conductor. As a result, the resilient supporting means will be distorted out of its natural state, and a portion of the conductive mass will come into contact with the stationary conductor. The contacting portion of the conductive mass will be pressed resiliently against the interfacing portion of the stationary conductor by the transverse component of the resilient supporting means, thereby minimizing the possibility of contact bounce. The axial component of the supporting means will yield resiliently to allow the conductive mass to pivot and thereby bring a larger area of the mass into contact with the stationary conductor. Thus, the closure time of this inventive disturbance switch will be prolonged until the elastic recovery action of the resilient supporting means draws the conductive mass away from the stationary conductor. In the absence of continued disturbance, the resilient supporting means will return to its static rest position, and the conductive mass will again be supported in spaced, coaxial relationship with the stationary conductor. Thus, the disturbance switch of this invention is restored automatically to its normally "open" position, after the prolonged closure time interval is completed.

One exemplary embodiment of this inventive switch comprises a frustoconical spring having a fixed, large diameter end and a free, smaller diameter end which supports a conductive ring in normally spaced, encircling relationship with a conductive center post. The ring and supporting spring constitute the movable member of the switch and the center post constitutes the stationary member. The frustoconical spring, commonly called a "volute spring," is essentially a cylindrical helical spring in the axial direction and a flat spiral spring in the transverse direction. The resiliency of the volute spring is predetermined to counteract the force of gravity acting on the ring, regardless of the orientation of the switch.

An alternative embodiment of this novel disturbance switch comprises an inverted volute spring having a fixed, small diameter end and a free, larger diameter end which supports a conductive disc in normally spaced, coaxial relationship with a surrounding, conductive wall of the switch enclosure.

Another alternative embodiment of this inventive switch comprises a stepped, cylindrical spring supporting a conductive cup in normally spaced, enveloping relationship with the distal end of a conductive center post. The stepped, cylindrical spring is, essentially, a helical spring having one end connected to an axially aligned, helical spring of larger diameter by a transversely disposed, spiral spring.

A third alternative embodiment, which constitutes an improvement on the first-mentioned exemplary embodiment, comprises a volute spring supporting a conductive ring in normally spaced, encircling relationship with a conductive center post, the ring carrying a parallel disposed, spiral spring of smaller inner diameter than the ring. Thus, the spiral spring reduces the annular gap between the inner diameter of the ring and the periphery of the center post, thereby rendering the switch more sensitive to slight disturbances. When the ring moves transversely with respect to the center post, the inner diameter of the spiral spring will contact the center post before the ring and will yield resiliently to allow a radially aligned portion of the ring to come into contact with the center post. When the contacting portion of the ring is drawn away from the center post, as previously described, the spiral spring will retain contact with center post for a short time thereafter. Consequently, the spiral spring carried on the ring will increase the closure time of the switch.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference is made to the accompanying drawings wherein:

FIG. 1 is an axial sectional view of a disturbance switch embodying this invention disposed in an upright position and including a schematic diagram of a typical connecting circuit;

FIG. 2 is an axial sectional view of a disturbance switch of the prior art with a schematic diagram of a typical connecting circuit;

FIG. 3 is an axial sectional view of the disturbance switch in FIG. 1 disposed in a prone position;

FIG. 4 is a cross-sectional view of the switch shown in FIG. 3, taken along the line 4--4, looking in the direction of the arrows;

FIG. 5 is an axial sectional view of the disturbance switch shown in FIG. 1 at the instant of closing;

FIG. 6 is an axial sectional view of the disturbance switch shown in FIG. 5 just after the instant of closing;

FIG. 7 is an axial sectional view of an alternative embodiment of this invention;

FIG. 8 is an axial sectional view of another alternative embodiment of this invention;

FIG. 9 is an axial sectional view of a third alternative embodiment of this invention; and

FIG. 10 is a cross-sectional view of the switch shown in FIG. 9 taken along the line 10--10 looking in the direction of the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring more particularly to the drawings wherein like characters of reference designate like parts throughout the several views, there is shown in FIG. 2 a disturbance switch 11 of the prior art. The switch 11 comprises a generally cylindrical housing 12 having an enclosing cap portion 14 which is peripherally sealed, as by welding, for example, to a circular base portion 16. The cap and base portion 14 and 16 are made of conductive material, such as kovar, for example, and the base 16 is provided with a centrally disposed aperture 18 having a predetermined diameter. An axial center post 20 of conductive material extends insulatingly through the aperture 18 and is circumferentially sealed to the periphery thereof. A rod 24 of conductive material is fixedly attached at one end to the exterior surface of the base 16 and extends outwardly therefrom in spaced relationship with the exterior portion 26 of center post 20. The rod 24 and the exterior portion 26 of center post 20 serve as respective terminals of the switch 11.

Disposed on the interior surface of the base 16 is a freely rollable ball 30 of conductive material. The ball 30 has a diameter such that it will span the dielectric bead 22 when contacting the center post 20. Thus, the contacting ball 30 will electrically connect the center post 20 to the base 16, thereby closing the switch 11. Also, the distal end of the center post 20 is disposed at a distance from the closed end of cap 14 which is less than the diameter of the ball. Thus, when the housing 12 is inverted the ball 30 will contact the post and will consequently close the switch 11 by electrically connecting the post 20 to the cap 14. However, the switch 11 will not function properly when the housing 12 is disposed on its side.

A typical circuit 32 for use with the switch 11 comprises a charging resistor 34 and a capacitor 36 connected in series across a battery 38, the resistor 34 being connected to the positive side of the battery. A resistor 40 and a silicon control rectifier 42 are connected in series across the capacitor 36, the anode terminal of the rectifier being connected to the positively charged side of the capacitor and the base terminal being connected to the resistor 40. The terminal rod 24 is connected to the gate of the silicon control rectifier 42 and the terminal 26 is connected to the positive side of the battery 38. The values of the resistor 34 and the capacitor 36 determine the time required for the battery 38 to store a charge on the capacitor. Since the rectifier 42 is in a normally nonconductive state, the charge remains stored on capacitor 36 until the switch closes.

In operation, when a force moves the housing 12, the ball 30 strikes the center post 20 and rebounds, thereby closing the switch momentarily. A typical closure time interval for this type of switch is about 10 microseconds. The resulting low current signal passing through the switch 11 is sufficient to trigger the gate of the silicon control rectifier 42, thereby rendering it conductive. Consequently, the capacitor 36 discharges through the silicon control rectifier 42 and the load resistor 40. Thus, the load resistor 40 may serve as a voltage source for a connecting auxiliary circuit having telemetry devices therein which will be activated by the current passing through the resistor 40. When the capacitor is discharged, the rectifier returns to its initial nonconductive state. The purpose of the rectifier in the circuit is to provide a conductive path for discharging the capacitor through the resistor even after the switch has reopened. Thus, a sufficiently strong current will flow through the resistor to activate complex telemetry devices in a connecting auxiliary circuit (not shown). However, if the switch remained closed for a sufficient length of time to discharge the capacitor through the load resistor, the rectifier would not be required.

As shown in FIG. 1, the mechanical disturbance switch 50 of this invention comprises a generally cylindrical housing 52 having an enclosing cap portion 54 peripherally sealed, as by welding, for example, to a circular base portion 56. The cap and base portions are made of conductive material, such as kovar, for example. An axial center post 60 of conductive material, such as gold plated steel, for example, extends insulatingly through a centrally disposed aperture 58 in the base portion 56, and is circumferentially sealed to the periphery of aperture 58 by means of intervening dielectric material, such as glass bead 62, for example. A rod 64 of conductive material, such as gold plated steel, for example, is fixedly attached at one end, as by brazing, for example, to the exterior surface of the base 56 and extends outwardly therefrom in spaced relationship with the exterior portion 66 of center post 60. The rod 64 and the exterior portion 66 of the center post 60 serve as respective terminals of the switch 50.

Within the housing 52, a frustoconical coil spring 70, commonly called a "volute spring," is disposed in spaced surrounding relationship with the interior portion of the center post 60. The large end portion of spring 70 encircles a cylindrical landing 72 on the interior surface of the base 56 and is fixedly attached thereto, as by welding, for example. The small end of spring 70 is free to oscillate and carries a conductive ring 74 which may be made of gold plated steel, for example. The ring 74 is provided with a shank portion 73 which is press-fitted into the small end of spring 70 and may be fixedly attached thereto by conventional means, such as metallic bonding cement, for example. The spring 70 is made of resilient material, such as stainless steel, for example, and is provided with sufficient tensile strength to counteract the force of gravity acting on the ring, regardless of the orientation of the housing 52. Thus, in the undisturbed state, the ring 74 is supported in spaced coaxial relationship with the center post 60.

The volute spring 70 functions as a cylindrical helical spring in the axial direction and as a flat spiral spring in the transverse direction, with respect to center post 60. As shown in FIG. 1, when the switch 50 is disposed in the upright position, the helical component of spring 70 counteracts the force of gravity acting on the ring 74 and determines the axial position of the ring relative to the center post. The spiral component of spring 70 positions the ring 74 transversely in relation to the center post 60 and maintains the ring in spaced coaxial relationship with the center post when the switch 50 is in the static state. In practice, when the ring is mounted on the small end of spring 70, the helical component of the spring yields resiliently, in the axial direction, until the elastic force generated by spring 70 equals the force of gravity acting on the ring 74. As a result, the coil turns of spring 70 adjacent the ring 74 are slightly compressed in the axial direction. However, the other coil turns of spring 70 remain helically spaced apart and support the ring 74 resiliently in the axial direction. Thus, in the undisturbed state, the ring 74 is maintained in balanced spaced relationship with the center post 60.

It also may be seen in FIG. 1 that when the switch housing 50 is inverted, the helical component of spring 70 will yield resiliently in the axial direction until an opposing elastic force generated by the spring equals the force of gravity acting on the ring. In this instance, the coil turns of spring 70, adjacent the ring 74, will be helically spaced apart a greater distance than the coil turns adjacent the base 56. However, the spring 70 is provided with sufficient tensile strength to retain the ring 74 in coaxial relationship with the center post 60 when the switch housing 50 is in the inverted position. On the other hand, if the tensile strength of spring 70 is excessive, the sensitivity of switch 50 will be adversely affected.

In FIGS. 3 and 4, it may be seen that when the switch housing 52 is in the prone position, the helical component of spring 70 positions the ring 74 axially with respect to center post 60. However, the spiral component of spring 70 counteracts the force of gravity acting on the ring 74 and determines the transverse position of the ring with respect to the center post 60 when the switch 50 is in the static state. When the switch 50 is placed in the prone position, the spiral component of spring 70 yields resiliently until the elastic force generated by the spring equals the force of gravity acting on the ring. Consequently, an arcuate portion of the spiral component is compressed slightly and an opposing arcuate portion is expanded correspondingly. In effect, as shown in FIG. 3, the coil turns of spring 70 move more nearly into overlying alignment on one side of the spring 70 and further out of overlying alignment on the diametrically opposing side of the spring. However, the spring 70 is provided with sufficient tensile strength, in the transverse direction, to counteract the force of gravity acting on the ring 74 and to maintain the ring in spaced eccentric relationship with the center post 60, when the switch 50 is in the undisturbed state.

When the housing 52 is in an oblique position, the helical and the spiral components of spring 70 cooperate in counteracting the force of gravity acting on the ring 74 and in maintaining the ring in spaced eccentric relationship with the center post 60. Thus, the ring 74 is supported in balanced spaced relationship with the center post 60 regardless of the orientation of the switch housing 52.

When the switch 50 is disturbed, as shown in FIG. 5, the ring 74 is jarred out of the balanced equilibrium state and impelled in the transverse direction relative to the center post 60. As a result, the attached, smaller diameter end of spring 70 is drawn away from its static rest position and an inner peripheral edge portion of the ring 74 at the end remote from the spring comes into contact with the center post 60. This initial contact portion or point is indicated by numeral 75. Due to the corresponding distortion of spring 70, the spiral component of the spring presses the contacting portion 75 against the center post, thereby minimizing the possibility of the ring striking the center post and rebounding therefrom. The helical component of the spring 70 yields resiliently in the axial direction and pivots the ring 74 about its initial contacting area 75. Thus, the linear portion of ring 74 in axial alignment with the contacting peripheral edge area 75 is brought into interfacing relationship with a corresponding linear surface area of the center post, as shown in FIG. 6. As a result, the closure time of this novel disturbance switch is prolonged until an elastic recovery force, developed by the correspondingly distorted spring 70, draws the ring 74 away from the center post 60. Subsequently, the ring 74 and the free, smaller diameter end of the spring 70 may oscillate for a short interval of time. However, if the initiating disturbance has ceased, the spring will return to its static rest position whereupon the ring 74 will be again supported by the spring 70 in spaced coaxial relationship with the center post 60, and the switch 50 will be restored to its normally "open" position.

Referring again to FIG. 1, the disturbance switch 50 is shown connected to a circuit 32a which is somewhat similar to the circuit 32 shown in FIG. 2. In circuit 32a, a charging resistor 34a and a capacitor 36a are connected in series across a battery 38a, the resistor 34a being connected to the positive side of the battery. A load resistor 40a and switch 50 are connected in series across the capacitor 36a, the load resistor 40a being connected to the negative side of the capacitor 36a. For example, the terminal rod 64 of switch 50 may be connected to the resistor 40a and the center post terminal 66 may be connected to the positive side of the capacitor 36a. Thus, the switch 50 is connected in circuit 32a in place of the silicon control rectifier 42 which is required for proper operation of circuit 32 shown in FIG. 2.

In operation, when the switch 50 is in the normally "open" or static condition, the battery 38a stores a charge on the capacitor 36a. Subsequently, a slight disturbance is sufficient to upset the balanced equilibrium of ring 74 in switch 50 and cause it to engage the center post 60 for a prolonged interval of time, as previously described. The resulting current passing through load resistor 40a is sufficient to trigger complex telemetry devices in an auxiliary circuit (not shown) which may be connected across load resistor 40a. Thus, due to the prolonged closure time provided by the switch 50, the silicon control rectifier 42, shown in FIG. 2, is not required in circuit 32a. To obtain the desired current flow from capacitor 36a to load resistor 40a, the closure time interval of switch 50 may be adjusted by varying the outer diameter of center post 60, the inner diameter of ring 74 and the diameter of the wire forming the volute coil spring 70.

FIG. 7 illustrates an alternative embodiment 78 of this inventive disturbance switch comprising a generally cylindrical housing 80 having a cup-shaped cap portion 82 and a transversely disposed base portion 84 which are made of conductive material, such as gold plated kovar, for example. The base 84 is inserted into the open end of cap 82 and peripherally sealed to the surrounding wall thereof by an intervening annulus 86 of dielectric material, such as glass, for example. Cap 82 and base 84 are provided with exterior projecting portions 88 and 90, respectively, which serve as respective terminal members of the switch.

Axially disposed within the housing 80 is an inverted volute spring 92 having a small diameter end encircling a cylindrical landing 85 on the interior surface of base 84 and secured thereto, as by welding, for example. The opposing large diameter end of spring 92 is free to oscillate and carries a transversely disposed disc 94 of conductive material, such as gold plated steel, for example. The disc 94 is provided with a reduced diameter shank portion 95 which is press-fitted into the open, large end of spring 92 and may be affixed thereto by conventional means, such as metallic bonding cement, for example.

The spring 92 functions as a cylindrical helical spring in the axial direction and a flat spiral spring in the transverse direction with respect to the cap 82. Thus, the helical component of spring 92 positions the flat, exposed surface of disc 94 in spaced parallel relationship with the closed end of cap 82, and the spiral component of spring 92 positions the peripheral rim of disc 94 in spaced coaxial relationship with the surrounding wall of cap 82. The helical and spiral components of spring 92 cooperate to maintain the disc 94 in balanced spaced relationship with the cap when the switch is in the static state. Therefore, the spring 92 is provided with sufficient tensile strength to counteract the force of gravity acting on the disc 94, regardless of the orientation of the switch housing 80.

In operation, the switch 78 functions in a similar manner to the switch 50 shown in FIG. 1. A slight disturbance upsets the balanced equilibrium state of the disc and causes it to move axially and/or transversely with respect to the cap 82. As a result, an edge portion of the disc 94 comes into initial contact with a portion of the surrounding wall of cap 82 or with a portion of the closed end of cap 82. In each instance, the helical and spiral components of the spring 92 cooperate to press the contacting portion of the disc 94 resiliently against the interfacing portion of the cap 82 thereby minimizing the possibility of contact bounce occurring. Also the helical and spiral components of the spring 92 cooperate in pivoting the disc 94 about its initial contacting area, thereby bringing a larger area of the disc into engagement with the cap 82. Thus, the switch 78 will close for a prolonged interval of time and will return automatically to a normally "open" position in a manner similar to the switch 50 shown in FIG. 1.

FIG. 8 illustrates a second alternative embodiment of this invention. The switch 96, shown in FIG. 8, is structurally similar to the switch 50, shown in FIG. 1, with the exception of the movable conductive members. In switch 96, the distal end of center post 60 extends axially into the open end of a conductive cup 98 which is movably supported by a stepped, cylindrical spring 100. The spring 100 is disposed in spaced coaxial relationship with the center post 60 and comprises an axially disposed helical portion 102 which is integrally joined to an axially aligned helical portion 106 of larger diameter by an intervening, transversely disposed, spiral portion 104. The helical portion 106 encircles the cylindrical landing 72 on the interior surface of base 56 and resiliently supports the spiral portion 104 which, in turn, resiliently supports the helical portion 102. The free end of helical portion 102 supports and may be affixed to the cup 98 by conventional means, such as metallic bonding cement, for example. When the cup 98 is mounted on the free end of helical portion 102, the spiral portion 104 may sag slightly in the axial direction with respect to the center post 60. This sagging does not adversely affect the operation of switch 96, but if it is found objectionable, the sagging may be minimized by providing the spiral portion 104 with a volute configuration.

The switch 96 clearly demonstrates the helical and spiral components of the supporting spring required in practicing this invention. The helical portions 102 and 106, respectively, position the cup 98 in the axial direction, and the spiral portion 104 positions the cup 98 in the transverse direction with respect to the center post 60. The spring 100 is provided with sufficient tensile strength to counteract the force of gravity acting on the cup 98, regardless of the orientation of the housing 52. Thus, the cup is supported in balanced spaced relationship with the center post 60 when the switch 96 is in the static state. When a disturbance upsets the balanced equilibrium of the cup 98, the switch 96 operates in similar fashion to the switch 50 shown in FIG. 1, thereby minimizing the possibility of contact bounce and achieving prolonged closure time.

A third alternative embodiment of this invention, shown in FIGS. 9 and 10, comprises a disturbance switch 110 which is structurally similar to the switch shown in FIG. 1, with the exception of the resiliently supported, movable contact member. The volute spring 70 in switch 110 resiliently supports a conductive ring 74a which has an annular cavity 112 disposed in the planar surface of the ring remote from the spring, adjacent the inner diameter thereof. A flat, yieldable spiral spring 114 having an outer diameter slightly larger than the outer diameter of cavity 112 is disposed in parallel relationship with the ring 74a and press-fitted into cavity 112. If necessary, an outer peripheral portion of spring 114 may be affixed to the curved wall of cavity 112 by conventional means, such as metallic bonding cement, for example. The spring 114 is made of resilient material, such as stainless steel, for example, and is provided with an inner diameter which is less than the inner diameter of ring 74a but greater than the diameter of center post 60. Thus, the spiral spring reduces the annular gap between the ring 74a and the center post 60, thereby rendering the switch 110 even more sensitive to slight disturbances than the switch 50, shown in FIG. 1.

In operation, the spiral spring is supported, by the ring 74 and volute spring 70, in spaced coaxial relationship with the center post 60, when the switch 110 is in the static state. However, when a slight disturbance occurs, the ring 74 is jarred out of its balanced equilibrium state and moves transversely with respect to the center post 60. As a result, the inner diameter of spiral spring 114 comes into contact with the center post 60 and yields resiliently as a radially aligned, arcuate portion of ring 74a continues to travel toward the center post 60. Thus, the switch 110 is closed by the spiral spring 112 before the ring 74a engages and makes prolonged contact with the center post 60, as previously described. When the elastic recovery force, generated by the distorted volute spring 70, draws the ring 74a away from the center post 60, the spiral spring 114 retains contact with the center post until it also eventually is drawn away by the supporting ring 74a. Thus, the switch 110 remains closed for a short time after the conductive ring 74a moves away from the center post 60. As a result, the prolonged closure time provided by the switch 50, shown in FIG. 1, is increased by having the spiral spring 114 mounted on the conductive ring, as shown in FIGS. 9 and 10. Furthermore, in addition to the previously mentioned variable parameters, the closure time of switch 110 also may be varied by changing the inner diameter of the spiral spring 114 or the diameter of the wire used in forming the spiral spring 114 or both.

Thus, there has been disclosed herein a novel disturbance switch which is not dependent on the force of gravity for its proper operation, which provides a prolonged closure time and which returns, automatically, to its initial state of readiness after completion of the required closure interval. The disturbance switch of this invention, essentially, comprises a stationary contact member disposed in coaxial, normally, spaced, relationship with a movable contact member which is supported by resilient means having axially and transversely directed components with respect to the stationary contact member. The orthogonally directed components of the resilient means cooperate in counteracting the force of gravity acting on the movable contact member, regardless of the switch orientation, and in supporting the movable contact member in balanced spaced relationship with the stationary contact when the switch is in the static state. As a result, even the slightest disturbances will jar the movable contact member out of the balanced equilibrium state and cause it to contact the stationary contact member, thereby closing the switch for a prolonged interval of time.

Although this novel switch has been illustrated herein as a disturbance sensitive device, it also may be applied to other fields, such as centrifugal force indicators, for example. Thus, the tensile strength of the resilient means may be adjusted to allow the switch to close only when the switch is spinning at a preselected angular velocity. For example, the diameter and material of the wire forming the volute spring 70 may be so chosen that the conductive ring 74 will move transversely with respect to the center post 60 only when acted upon by a predetermined centrifugal force. The switch then may be mounted offcenter on a spinning object and closure of the switch will indicate when the attached object has attained the preselected angular velocity.

From the foregoing, it will be apparent that all of the objectives of this invention have been achieved by the structures shown and described. It also will be apparent, however, that various changes may be made by those skilled in the art without departing from the spirit of the invention as expressed in the appended claims. It is to be understood, therefore, that all matter shown and described is to be interpreted as illustrative and not in a limiting sense.

Claims

I claim:

1. A disturbance sensitive switch comprising:

a stationary conductor and a movable conductor disposed in operative relationship with one another; and

resilient means secured to the movable conductor for entirely supporting the movable conductor and having orthogonally directed helical and spiral components with respect to the stationary conductor for maintaining the movable conductor in operative spaced balanced relationship with the stationary conductor independently of the orientation in any direction of the switch in the static state.

2. A disturbance sensitive switch as set forth in claim 1 wherein the movable conductor is hollow and disposed in encircling relationship with the movable conductor, the helical component is disposed in coaxial relationship with the stationary conductor and the spiral component comprises continuous filamentary turns having progressively decreasing radii and extending radially inward from the helical component toward the stationary conductor.

3. A disturbance sensitive switch as set forth in claim 1 wherein the stationary conductor is hollow and disposed in encircling relationship with the movable conductor, the helical component is disposed in coaxial relationship with the stationary conductor and the spiral component comprises continuous filamentary turns having progressively increasing radii and extending radially outward from the helical component toward the stationary conductor.

4. A disturbance sensitive switch comprising:

an elongated stationary conductor;

a cylindrical conductor disposed in normally spaced coaxial relationship with the stationary conductor; and

resilient means for entirely movably supporting the cylindrical conductor and having orthogonally directed, helical and spiral components with respect to the stationary conductor for minimizing contact bounce and maintaining the cylindrical conductor in prolonged contact with the stationary conductor when the switch is disturbed,

the helical component extending coaxially with the stationary conductor and the spiral component comprising continuous filamentary turns of progressively varying radius extending radially from the helical component toward the stationary conductor.

5. A disturbance sensitive switch as set forth in claim 4 wherein the supporting resilient means is a volute spring.

6. A disturbance sensitive switch as set forth in claim 4 wherein the supporting resilient means is a stepped cylindrical spring.

7. A disturbance sensitive switch as set forth in claim 4 wherein said cylindrical conductor includes radially protruding yieldable means for reducing the normal space between the cylindrical conductor and the stationary conductor.

8. A disturbance sensitive switch as set forth in claim 7 wherein the yieldable means comprises a flat spiral spring carried on the cylindrical conductor.

9. A disturbance sensitive switch comprising:

a support;

two electrical terminals affixed to the support and electrically insulated from one another;

an elongated conductor having one end affixed to the support and electrically connected to one of said terminals;

a hollow conductor disposed in encircling relationship with a portion of the elongated conductor and electrically connected to the other of said terminals; and

resilient means for entirely movably supporting the hollow conductor and having a helical component directed longitudinally and a spiral component directed transversely with respect to the elongated conductor for maintaining the hollow conductor in normally spaced balanced relationship with the elongated conductor independently of the orientation of the switch in the static state.

10. A disturbance sensitive switch as set forth in claim 9 wherein the resilient means comprises a spring having a helical component disposed in normally spaced coaxial relationship with the elongated conductor and a spiral component comprising continuous filamentary turns of progressively decreasing radius extending radially inward from the helical component toward the elongated conductor.

11. A disturbance sensitive switch as set forth in claim 10 wherein the spring is a volute spring disposed in surrounding relationship with the elongated conductor and electrically insulated therefrom, said spring having a larger diameter end affixed to the support and an opposing smaller diameter end secured to the hollow conductor.

12. A disturbance sensitive switch as set forth in claim 10 wherein the hollow conductor comprises a conductive ring carried on the smaller diameter end of the volute spring.

13. A disturbance sensitive switch as set forth in claim 12 wherein the hollow conductor further comprises a flat spiral spring carried on the ring and having an inner diameter less than the inner diameter of the ring but sufficiently large to be spaced from the elongated conductor when the switch is undisturbed.

14. A disturbance sensitive switch as set forth in claim 10 wherein the spring is a stepped cylindrical spring disposed in spaced surrounding relationship with the elongated conductor, the spring having a larger diameter end affixed to the support and an opposing smaller diameter end secured to the hollow conductor.

15. A disturbance sensitive switch as set forth in claim 14 wherein the hollow conductor is a conductive cup disposed in enveloping relationship with the distal end of the elongated conductor and secured to the smaller diameter end of the spring.

16. A disturbance sensitive switch comprising:

a cup-shaped conductor defining a cavity;

a conductive support disposed adjacent the opening of the cup-shaped conductor and insulatingly attached to the wall thereof;

a conductive mass disposed within the cavity in the conductor; and

resilient means for entirely supporting the conductive mass and having orthogonally directed helical and spiral components with respect to the wall of the conductor for maintaining the conductive mass in normally spaced balanced relationship with the surrounding wall of the cavity independently of the orientation of the switch in the static state and for maintaining the conductive mass in prolonged contact with said wall when the switch is disturbed,

the helical component of the resilient means being disposed coaxially within the cup-shaped conductor and the spiral component comprising continuous filamentary turns of progressively increasing radius extending radially outward from the helical component toward the wall of the conductor.

17. A disturbance sensitive switch as set forth in claim 16 wherein the resilient means comprises an inverted volute spring axially disposed within and normally spaced from the surrounding wall of the cavity, the spring having a smaller diameter end affixed to the conductive support and an opposing larger diameter end secured to the conductive mass.

18. A disturbance sensitive switch as set forth in claim 17 wherein the conductive mass is a disc transversely disposed in the cavity and carried on the larger diameter end of the volute spring.