US2205281A - Air operated switch - Google Patents

Description

Patented June 18, 1940 UNITED STATES PATENT OFFICE AIR OPERATED SWITCH Application November 19, 1937, Serial No. 17 5,425

9 Claims.

This invention relates to electric switches of the quick make and break type, and particularly to those actuated by air streams of varying intensity.

One object of the invention is to provide a switch sensitive enough to respond to air streams of low potential, and that will effect a quick make and a quick break of the circuit connections with a minimum of arcing at the contact points.

A further object is to provide a sensitive circuit control mechanism, with means for critically adjusting the point of contact opening and contact closing.

A further object of the invention is to provide means in a sensitive switch for holding the contacts in a normally closed position until predetermined conditions are experienced, and on the manifestation of which the contacts will open with a snap action.

A further object of the invention is to provide means for critically adjusting the mechanism to a desired point of contact opening, as well as to a desired point of contact closing,

a which two points of contact actuation may be relatively widely separated.

A further object of the invention is to provide an air operated switch, in which the contacts will be maintained closed for predetermined low potential air streams, and will thereupon open with a snap action and remain open even though the air stream potential may fall to a lower value than that of the initial actuating force, whereupon the contacts will close through the influence of the same means with a snap action.

A further object of the invention is to provide magnetic holding means in a switch device, whereby the contact opening and the contact closing will both be responsive to the snap action.

A further object of the invention is to provide a magnetic holding means for circuit closers, wherein the holding function can be adjusted to suit the conditions under which the switch is used.

A still further object is to provide an electric switch of the normally closed contact type, that will work with a snap action to open a circuit in response to a predetermined actuating force, and thence operate to close a circuit in response to a predetermined actuating force materially less than the force required to open the circuit.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Fig. 1 is a plan view with parts shown in section, illustrating one form of an air stream sensitive switch, the parts being illustrated in the circuit closed position.

Fig. 2 is a similar view, illustrating the parts moved to a circuit open position.

Fig, 3 is a transverse sectional view, substanw tially as indicated by the line and arrows 3-3 of Fig. 1.

Fig. 4 is a transverse sectional view, substantially as indicated by the line and arrows 4-4 of Fig. 1.

Fig. 5 is a top plan view, of a modified form of an air stream responsive switch, the contacts being shown in the circuit closed position.

Fig. 6 is a similar view, showing the parts moved to circuit open position.

Fig. 7 is a side elevation, of the form shown in Fig. 5.

Fig. 8 is a transverse sectional view, substantially as indicated by the line and arrows 8-8 of Fig. 5, and Fig. 7.

In the art of air operated switches, much difficulty has been experienced in designing and calibrating a mechanism that would be sensitive enough to respond to slight variations in air velocities of low magnitude, and yet would be rugged enough to give extended service, and not be damaged by continued and hard usage. Other difficulties have presented themselves in the way of causing a flutter of the actuating element, when subjected to air streams but little difierent in force than that at which the device Was set to respond. As an example, suppose it be desirable to have an air operated switch preform a circuit opening function at 15 m. p. h., and that the switch isinstalled upon a vehicle operating at a speed of perhaps 15.5 m. p. h. Under this assumption, the air force upon the vane of the switch, for some reason or other might be gusty in nature, but in any event Would result in an irregular though frequent and alternate contact opening and contact closing function without any apparent change of vehicle speed. The result is undesirable, since the control effected by the switch would thereby be irregular and uncertain, if not undesirable.

The foregoing objects have been accomplished, and the stated problems have been solved, by incorporating a holding means that is adapted to standardize, or stabilize, the contact actuation at the low air stream velocities, in that the con- June 18, 1940. E. M. CLAY TOR AIR OPERATED SWITCH Filed Nov. 19, 19:7

n 5 4 I 7 7 7 I 5 F Z y ws m n 9 TU N J m m L WM n F i 5 Y O 4MB 0 arm l9, by means of an air vane or paddle. 2|. Return movement of the arm l9 to the rest position is assured by a spring 23, one end 25 of which is hooked upon one or another of a plurality of lugs 21, on the arm l9, while the other end 29 hooks behind one or another of a plurality of lugs 3| of a plate 33, secured to the plate II by the end of the sleeve l5, which is peened over or otherwise secured asat 35. The arm l9 has an extension 3! that ends in an armature portion 39 urged into close proximity to a magnet 4| supported by a block of insulation 43, which insulated block is in turn secured to the base II by means of a shouldered stud 45. The extension 31 supports a movable contact 41, and the intermediate portion is looped or bowed as: at 49 to partially embrace the stud 45, when the contact bearing arm ismoved into the circuit open position, substantially as illustrated in Fig. 6. Surrounding the magnet 4|, or at least disposed between the magnet 4| and the armature portion 39, there is a piece of nonmagnetic material 5| that prevents freezing of the armature 39 to the magnet 4| when the switch device is in the rest position.

A relatively fixed contact 53 is mounted on a spring arm 55, extending from a bracket 51 mounted in insulated relation on the base I, and is provided with an exterior terminal 59.

Means are provided for securing a cover assembly over the working parts, as in the form earlier described, though no cover is shown in the drawing, and contemplates passing the cover aperture over the threaded projecting end of the stud 45, where it may be secured by a nut on the exterior thereof as in the earlier described form. For the purpose of positioning or locating the flanged edge of the cover, the base H is fashioned to provide the squirts or extrusions 6| in the base II, that engage with the inner surface of the cover flange. In the form illustrated in Figs. 1 to 4, these extrusions are likewise shown in the position relative to the cover 96. In either instance an appropriate gasket 63, for perfecting a weather tight seal, may be inserted between the edge of the cover and the base.

Either modification of the switch structure provides a device that is sensitive, or can be adjusted to be sensitive, to air stream movements of low potential, though the structure in either instance is rigid enough to properly function throughout a long period of service. After once being adjusted it needs no further attention to operate with unfailing fidelity under the desired conditions.

As for operation, in controlling the circuits within which they are inserted, either device is equally effective. Let it be assumed that the switch is to be inserted in a circuit, such as the volume control of radio, or a lock-out for free wheeling, and particularly the latter wherein it may be desirable to disconnect the free wheeling feature from the automobile for engine speeds above 20 m. p. h., and maintain that circuit open until the car speed falls below m. p. h. The physical structures are thence adjusted such that the air stream indicated at I00, created by the engine cooling fan or other air moving device will actuate the paddle 24 with sufficient force to overcome the holding force of the return spring and the magnet or the holding device. Under these conditions as soon as the armature of the contact carrying arm starts to move away from the magnet, the magnetic force by which the contacts have been maintained in circuit closed position, rapidly falls away, and the stored up pressure against the paddle 24, having an appreciable portion of its resisting force done away with, is effective to snap the armature against the stops, it being attended by a quick break of the circuit connections. On the other hand, should the impelling force against the paddle 24 or 2| fall away even to a lower value than that at which the contacts are open, the circuit connections will be maintained open, until the force acting upon the paddle 24 approaches the value at which the mechanism has been adjusted to cut-in, or reestablish. This cut-in value may in the assumed instance be at a vehicle speed of about 15 m. p. h. or some other speed less than the assumed m. p. h. for circuit opening. This is made possible by reason of the fact, that as the wind pressure upon the paddle 24 decreases, the return spring will tend to retract the armature toward its rest position, and during which it approaches and finally becomes re-immersed in the field of the magnet. When this approach is sufficient that the armature is disposed in attractive relation with respect to the magnet, then the return force of the contact supporting arm is accelerated, which manifests in closing of the contacts with a snap action.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is a follows:

1. An air operated switch comprising in combination, an oscillatable shaft, an arm driven by the shaft and carrying a movable contact, means providing a relatively fixed contact in cooperable relation therewith, said shaft and arm being spring urged to contact closed position, magnet means for pulling upon the arm when the contacts are in closed relation, and an extension of said arm adapted to be attracted by the magnet means when the contacts are in wide open rela-- tion.

2. An air operated switch comprising in combination, a vane responsive to movement of air currents, a contact carrying arm having a flange with an offset, a shaft rigidly joining the vane and arm, a base supporting the shaft for oscillatable rotation, a permanent magnet rigidly fixed to the base, spring means urging the flange of the arm into the field of the magnet, said vane being operable to move the arm flange out of the magnetic field, and to move the flange off-set into the field.

3. The combination set forth in claim 2, wherein stops are provided for limiting the approach of the arm and offset toward the magnet.

4. An air operated switch comprising in combination, a vane responsive to movement of air currents, a contact carrying arm having a flange with an offset, a shaft rigidly joining the vane and arm, a base supporting the shaft for oscillatable rotation, a permanent magnet rigidly fixed to the base, spring means urging the flanges of the arm into the field of the magnet, said vane being operable to move the arm flange out of the magnetic field, and to move the flange off-set into the field and means including spring supporting lugs provided by the arm for altering the urging frame by which the arm is moved into the field of the magnet.

5. An air operated snap switch, comprising in combination, a base providing a relatively fixed contact, an oscillatable arm carrying a movable contact, an armature having an angular offset carried by the arm, means normally urging the arm into contact closed position, magnet means mounted on the base and whose field normally immerses the armature while the contacts are closed, an air operated vane for moving the arm to contact Open position, and for withdrawing the armature from the magnetic field and means for preventing engagement between the armature and magnet means.

6. The combination set forth in claim 5, wherein the last named means comprises an adjustable stop engaging the arm in its rest position.

7. The combination set forth in claim 5, wherein the last named means comprises a non magnetic member disposed between the arm and the magnet.

8. An air operated switch having open-contact and closed contact positions and comprising in combination, an oscillatable shaft, an arm driven by the shaft and carrying a movable contact, means for providing a relatively fixed contact in cooper-able relation therewith, said shaft and arm being spring urged to one contact relation, magnet means for pulling upon the arm while in the said last mentioned contact relation, and an extension of said arm adapted to be attracted by the magnet means while the arm is in the other contact relation, and actuating means including an air operated vane for moving the arm from the spring urged contact relation to said other contact relation.

9. A switch having relatively movable contacts and operable into circuit open and circuit closed positions, a shaft, an arm driven by the shaft for moving one of the contacts, a vane for moving the shaft to operate the switch into one position, a spring for moving the shaft to operate the switch into another position, magnet means pulling on the arm when in one switch position, and an extension of said arm attracted by the magnet when the switch is in another position.

EDWARD M. CLAYTOR.

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