US2255556A - Air switch - Google Patents

Description

Sept. E. M. CLAYTOR AIR SWITCH Filed Feb. 28, 1958 'INVENTOR EDWARD M. CLAYTOR BY v w ATTORNEY4 Patented Sept. 9, 1941 AIR SWITCH Edward M. Olaytor, Anderson,

Ind, assignor to General 'Motors Corporation, Detroit, Mich a corporation of Delaware Application February 28, 1933,-Seriai No. 193,932

6 Claims.

This invention relates'to delayed action snap switches, meaning the'type of switch having an operating member which-moves through a substantial portion of its maximum movement before the switch contact member is moved. During movement of the operating member before the contact member moves energy is stored in a spring which ultimately aifects the movement of the contact member with an abrupt, snappy movement. In this type of switch the movable contact member is held in either of its positions by a substantial frictional force. This requires that a substantial force be applied to the operating member to store energy in the spring and to 'move the spring into such location that the frictional force holding th contact member in one of its positions will be overcome so that the contact member will snap into the other of its positions.

It is an object of the present inventionto provide a switch which will snap open or snap closed with the application of a very small force upon the'operating member such as, for example,

the force exerted by wind pressure upon a relatively small vane. The requirements of the switch are such as to preclude the use of frictional means for holding the movable contact member in either of its limiting positions while the operating member is being moved to change the bias of the transfer spring with reference to the movable contact member.

In order to accomplish the purposes of the present invention I have employed a small permanent magnet which cooperates with magnetizable parts of the switchcontact member to hold the same in either of its operating positions. In this way I am able to provide a snap switch responsive to variations in relatively small operating force exerted upon the operating arm. The present invention is particularly adapted for operation in response to variations in wind current. I am able to elfect a relatively sensitive air switch and one which has a relatively Wide differential in air velocity effecting the opening, and permitting the closing of the switch.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanyembodying the present invention in two-operatsectional view in which Figs. 3

.together with the ing positions, the switch cover being shown in section.

Figs. 3 and 4 are views similar to Figs. 1 and 2 respectively, but with certain parts omitted. The and 4 is taken is on the line 3-3 of Fig. '7.

Fig. 5 is a sectional view on the line 55 of Fig. 1.

Fig. 6, is a view in the direction of the arrow 6 of Fig. 1.

Fig. '7 is a sectional view on the line 'i'i-of Fig. 1.

The switch comprises a base member 29-integral with the mounting bracket portion 2! having holes 22 for receiving screws 23 by which thebase 29 may be mounted upon a support. The base 24] insulatingly supports on the underside thereof as shown in Fig. 5, a terminal bar 24, and on the upper side thereof a phosphor bronze leaf-spring contact arm 25. These parts insulating members are secured to the-base by rivets -23 which also attach to the base a -plate 2? which has an upstanding ear .28 carrying an adjustable stopangular portion ii. These armature portions 49 and 4! cooperate, respectively, with the side and end of a cylindrical permanent magnet 42 which is carried by a non-magnetizable block 53. The block 43 is shaped so as to expose the side 42a of the magnet asshown in Fig. 5 and to expose the end 4227 as shown in Figs. 1, 2, 3 and l. Therefore, when the switch arm 33 is in the position shown in Figs. 1 and 3, the magnet 42 tends to hold it in that position; and, when the arm 33 is in the position shown in Figs. 2 and 4, the magnet 22 tends to hold it in this position also.

The block 43 is secured in position by a screw 50 having the two threaded portions 5| and 52 and an intermediate hexagonal portion 53. Between the base 29 and the portion 53 are located the block 43, an adjustable stop member 54 and a look washer 55. The stop member 54 is engaged by the flange portion 4! of the arm 43 as shown in Figs. 1 and 3. The stop member 54 comprises a circular portion E ia which is located eccentrically with respect to the screw 50. By loosening the screw 53 and turning the stop 54, the stop portion 53a can be adjusted so as to vary the distance through which the arm 33 moves clockwise with respect to the magnet 42, hence, to vary the width of the air gap between the armature portion 43 of the arm 33 and the side 42a of the magnet 42. By adjusting the screw 23, the air gap between the end 422) of th magnet and the flange 4| can be varied.

Th screw-threaded portion 52 of the screw 50 extends through the cover 60 which is secured in position by nut 6i threaded on to the screw 50.

The switch actuating means includes a shaft 13 journalled in the bearing 35 and carrying at its lower end, as viewed in Fig. 7, a hub member ll having a threaded extension which receives a nut 12 for clamping to the hub H an car 13 formed integral with a vane 14 which is to be operated by an air current. The upper end of the shaft i3 is provided with a shoulder 15 which bears on the upper end of the hub 34. The shaft is secured at its upper end to an arm 16 provided with an ear H to which one end of a helical coil spring 18 is attached. The other end of spring 18 is attached to screw 53. The spring 18 urges the arm 16 clockwise until a stop lug 19 of the arm 16 bears against the screw 53. The tension on the spring 18 can be varied by bending the ear Tl.

As shown in Figs. 4 and 7 a helical spring 83 surrounds the hub 34 of arm 33 and has its two ends 8! and 82 extending outwardly alongside a lug 83 extending downwardly from the arm 16 and a lug 84 extending upwardly on the arm 33. The lugs 33 and 84 are provided with small notches as shown in Figs. 6 and '7 which receive the ends SI and 82 of the spring 83. The spring 80 is so biased that its spring-end 8| tends to move the lugs 33 and 84 clockwise and the springend 82 tends to move these lugs counter-clockwise. The depth of the spring notches in these lugs is such as to provide a slight amount of lost motion between the lug 83 and the spring-ends 8| and 82.

A lost motion connection is provided between the operating arm 16 and the contact-carrying arm 33 by providing the latter with spaced stoplugs 90 and 9t between which the lug 83 of arm is movable.

The operation of the switch is as follows: The normal or at rest portion of the switch is shown in Figs. 1 and 3. In this portion of the switch, the spring l8 urges the arm 16 clockwise so that the arm flange l3 bears against the screw 53 thereby holding the vane M in the position shown in Figs. 1 and 4. The spring-end 82 is biased against the lug 83 in a counter-clockwise direction, and the spring-end 8| is biased against the lug 84 of contact arm 33 in a clockwise direction, thereby urging the arm 33 into the position shown in Figs. 1 and 3 wherein the arm flange 40 is in close proximity to the magnet side 42a.

As the wind velocity increases the resistance offered by the spring E3 is overcome and the vane l4 moves from the position shown in Figs. 1 and 3 to that shown in Figs. 2 and 4. During movement of the vane 14 counter-clockwise the lug 83 of control arm 16 moves counter-clockwise and away from spring-end 82 into engagement with spring-end B l, thereby moving spring-end 8| away from lug 8!; of contact arm 33, thereby causing said spring 83 to tend to bias the contact arm 33 in a counter-clockwise direction. Contact-arm 33, however, is not moved immediately because the magnet 42, in cooperation with the flange 48 of arm 33, restrains movement of arm 33 in this direction. Therefore the arm 16 continues to move counter-clockwise thereby storing up energ in the spring so tending to separate the flange 43 from the magnet side 42a; but this separation does not take place until the lug 83 has engaged the stop of arm 33. When due to sufficient wind velocity, the pressure exerted by lug 83 against stop lug 98 is such as to overcome the magnetic force exerted by the magnet 42 upon the flange 40 of arm 33, then the arm 33 moves from the position shown in Fig. 3 quickly and abruptly into the position shown in Fig. 4. Movement of this arm 33 into this position is accelerated due to the energy stored up in spring 80. Consequently the contact 3| is separated from the contact 30 by an abrupt movement. The leaf spring stationary contact arm 25 bends appreciably toward the right, as viewed in Fig. 3, as the arm 33 begins its movement in a. counterclockwise direction. Therefore, the contact 33 carried by the arm 25 follows along in engagement with the contact 3'! carried by arm 33 so that, when separation of contacts 30 and 3| finally occurs, there is an appreciable turning moment of the arm 33 in the counterclockwise direction. Movement of the contact arm 33 into the position shown in Fig. 4 brings its armature flange 4! into proximity to the pole face 421); consequently, the magnet 42 exerts a force of attraction tending to hold the arm 33 in contact-separating position as shown in Fig. 4.

As the wind velocity decreases, the spring 18 moves the arm 16 in a clockwise direction, thereby permitting the lug 83 to move away from the spring-end 8| and into engagement with the spring-end 82 whereupon the spring 83 tends to bias the contact arm 33 in a clockwise direction, thereby tending to move the armature flange il away from the poleface 42b of magnet 42; but this movement does not take place immediately upon reversal of the biasing of spring 83 owing to the attraction force of the magnet 42. When the wind velocity has diminished so that spring it turns the arm :6 into position to cause the arm lug 83 to engage the stop lug 9| of arm 33 the bias exerted by the spring 80. in a clockwise direction is against the arm 33 and is at a maximum. Further movement of the arm 76 clockwise due to further decrease in wind velocity permits the spring l8 finally to overcome the attracting force of the magnet 42, whereupon the arm 33 quickly moves or snaps from the position shown in Fig. 4 to that shown in Fig. 3, this movement being accelerated due to the fact that energy has been stored in the spring 83.

From the foregoing description of the construction and mode of operation of the switch embodying the present invention it is apparent that the switch comprises a switch contact arm and a switch actuating arm having a lost-motion connection with the switch contact arm. The switch contact arm is held in either of its limiting positions by a permanent magnet. So far this description applies to the magnet controlled switch of my copending application, Serial No. 191,937 filed February 23, 1938. The switch of the present application, however, diiiers from the switch of my copending application in that a bias spring is interposed between the operating arm and the contact arm, which arms are provided with parts cooperating with the biasing spring whereby the bias of the spring with reup in this biasing spring is due to the fact that the contact arm is held in either of its limiting positions by the permanent magnet, the energy ofthe biasing spring remaining unreleased until after the lost-motion connection between the operating arm and the contact arm is taken up.

I am able to provide a relatively sensitive switch, that is, one which is sensitive to very slightvariations in wind velocity because I do not attempt to retain the switch contact arm either in its contact making, or contact breaking pos tion by frictional force, but I employ a small permanent magnet for this purpose. Since I do not have to overcome a frictional force such as is present in the toggle action snap switch, I can use a relatively light biasing spring. Since I can use a relatively light biasing spring, I can use a relatively light restoring spring which operates upon tr e control arm in response to wind pressure. Therefore I am able to provide an automatic circuit controller responsive to variations in small forces, such as applied by wind to a vane of relatively small dimension. Such a switch has a fairly wide differential in operating force which effects the opening or closing of the switch. The switch is therefore adapted for use for controlling circuits of an automobile upon which the switch may be mounted in proximity to the engine cooling fan. Also the switch is well adapted for use to control an. electric gen erating plant operated by a wind wheel. There are of course many other uses to which a switch embodying the present invention is readily adapted.

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 follows.

What is claimed is as follows:

1. An electric switch comprising a supporting base; a housing supported on the base to provide a compartment between the base and the closed end of the housing; a bearing supported adjacent one corner of the base and projecting upwardly into the compartment; a shaft journaled within the bearing and extending above the bearing; a horizontally disposed driven plate journalled upon the bearing and providing an upper and a lower space within the compartment; a drive plate attached to the shaft and located in the upper space; spring means for transmitting motion between the plates; a switch located in the lower space including a stationary contact and a movable contact carried by the driven plate; a block supporting a bar magnet located within the lower space; an armature carried by the driven plate and movable in the lower space, said armature cooperating with each pole of the magnet; a rod located adjacent another corner of the base in parallel relation to the bearing and shaft, said rod securing the block to the base and cooperating with nut means for securing the housing to the base, and said rod forming a stop for limiting the movement of the plates in one direction; and a return spring for the drive plate, said spring having one end anchored to the rod and the other end to the drive plate.

2. An electric switch comprising a supporting base; a switch case cooperating with the base and defining a switch enclosing compartment located between the base and an end wall of the case spaced from the base; a bearing supported by the base at right angles thereto; a shaft extending through the base to a point near the case end wall and journalled within said bearing; a drive plate attached to the shaft and located adjacent the case end wall; a driven plate located between the base and the drive plate and parallel therewith and journalled upon said bearing; spring means located between the plates for yieldably transmitting motion between them; switch contacts located between the base and driven plate and comprising a stationary contact supported by the base and a movable contact supported by the driven plate; a bar magnet supported by the base; an armature provided by the driven plate and cooperating respectively with an end surface and a side surface of the bar magnet and movable with the driven plate in the space between the base and the driven plate.

3. An electric switch comprising a supporting base; a switch case cooperating with the base and defining a switch enclosing compartment located between the base and an end wall of the case spaced from the base; a bearing supported by the base and projecting into the compartment; a shaft journalled within the bearing and having one end extending beyond the bearing within the compartment; a driven plate journalled upon the bearing within the compartment; 2. drive plate supported on the extended end of the shaft and rotatable therewith and spaced from the driven plate; spring means located between the plates for yieldably transmitting motion between the plates; switch contacts located between the base and driven plate and including a relative stationary contact and a movable contact supported by the driven plate; a permanent bar magnet supported within the compartment; an armature provided by the driven plate and cooperating respectively with an end surface and a side surface of the bar magnet and movable with driven plate in the space between the base and the driven plate.

4. An electric switch comprising a supporting base; a bearing supported by the base; an actuating shaft journalled within the bearing; a driven plate rotatably supported on the bearing and having an armature flange and a contact flange; a relative stationary contact supported from the base and located between the flanges; a drive plate fixed to the shaft and located above the driven plate; spring means for yieldably transmitting motion between the plates; a bar magnet carried by a block with poles adapted to cooperate with the armature flange to hold the contact flange in contact closed and open posi tion, respectively; a rod for securing the block to the base, said rod acting as a stop for the drive plate; a return spring having one end fixed and the other end connected to the drive plate to hold normally the drive plate against the rod; an enclosure for the switch parts and the bar magnet; and means cooperating with rod for securing the enclosure to the base.

5. An electric switch comprising in combination; a supporting base; a bearing supported by the base; an actuating shaft journalled within the bearing; a driven plate having an angular armature flange and a contact flange, said plate being journalled on the bearing and the shaft; a relatively fixed contact carried by the base; a

drive plate movable with the shaft and located above the driven plate; spring means for yieldably transmitting motion between the plates; a bar magnet supported on a block with the poles of the magnet located between the angular portions of the armature flange; a rod for securing the block to the base, said rod acting as a stop for the drive plate in one direction; a return spring for the drive plate having one end anchored to the rod and the other end attached to the drive plate; an enclosure for the switch parts and the bar magnet; and means cooperating with rod for securing the enclosure to the base.

6. An electric switch comprising in combination a base; a bearing carried by the base; an actuating shaft journalled in the bearing; a relatively fixed contact carried by the base i a contact plate journalled on the outside of the bearing and on the shaft; a drive plate attached to one end of the shaft above the contact plate; spring means for yieldably transmitting motion between the plates; a bar magnet supported by a block; a rod cooperating with the base to secure the block to the base, said rod providing stops for the drive plate and the contact plate; a return spring located between the plates and having one end anchored to the rod and the other end connected to the drive plate; a cover for enclosing the switch elements and the bar magnet; and means cooperating with the rod for securing the cover to the base.

EDWARD M. CLAYTOR.

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