US2427792A

US2427792A - Preselection control device

Info

Publication number: US2427792A
Application number: US514956A
Authority: US
Inventors: William P Lear
Original assignee: Lear Inc
Current assignee: Lear Inc
Priority date: 1942-02-25
Filing date: 1943-12-20
Publication date: 1947-09-23
Anticipated expiration: 1964-09-23

Description

Sept. 23,1947. w P,| EAR 2,427,792

PRESELECT ION CONTROL DEVICE Original Filed Feb. 25, 1942 v i- 7 2 v.

, iNVENTOR Ilka/1M2 Lam T314. Y "E F ATIORNEY Patented Sept. 23, 1947 PRESELECTION CONTROL DEVICE William P. Lear, North Hollywood, Calif., assignor, by mesne assignments, to Lear, Incorporated, Grand Rapids, Mich., a corporation of Illinois Original application February 25, 1942, Serial No. 432,195,,now Patent No. 2,355,381, dated August 8, 1944. Divided and this application December 20, 1943, Serial No. 514,956

3 Claims.

The present invention relates to a switch assembly particularly adapted for use in the preselection control mechanism covered by U. S. Patent 2,355,381, issued on August 4, 1944, to the present inventor and assignee on an application filed February 25, 1942, of which this application is a division. Switch mechanisms used heretofore for such applications have generally been relatively complicated and expensive as well as unreliable in operation. The present invention provides a switch assembly including a pair of control switches, preferably of the snap action type, operable by a cam which is operatively associated with the plungers of the switches. Simple and effective adjusting mechanism is provided for adjusting the position of the switches with respect to the operating cam.

Normally, the cam is in a neutral position in which both switches are open. Upon displacement of the cam a minute amount in either direction, one or the other of the switches is closed to effect a control operation. When the control operation is completed, the cam is restored to its neutral position which effects opening of the previously closed switch.

The advantages, features and capabilities of the switch assembly invention will become more apparent from the following description of a preferred embodiment thereof, illustrated in the accompanying drawings. In the drawings:

Fig. 1 is a sectional elevation of apparatus embodying the invention;

Fig. 2 is a section taken along line '2--2 of Fig. 1;

Fig. 3 is a section taken along line 3--3 of Fig. 1; and

Fig. 4 is a section taken along line 4--4 of Fig. 3.

The control head depicted in sectional elevation in Fig. 1 comprises a casing fitted with a back plate 16. A control knob ll extends from casing 15. A pointer I8 is secured to knob H, with a dial arranged behind. Dial 2D is provided with suitable markings for comparison with a reference mark, not shown, suitably arranged on the casing. The periphery of dial 29 is knurled to facilitate its manual adjustment.

An indicating lamp 23 is arranged on casing l5. Electrical cable l9 detachably connects the electrical section of control head 15 with a circuit to be controlled.

A worm gear 33 suitably driven by a worm not shown, is secured to a friction plate through hub 34 of gear 33 and countersunk screws 36. Friction plate 35 is juxtaposed with the dial 20.

A spring washer 31 is interposed between housing l5 and friction plate 35, urging plate 35 against dial 20. A control shaft 49 extends through dial 20, friction plate 35, hub 34, and gear 33. Control knob I1 is secured to the outer end of shaft 40 by set screw 38. The other end of shaft 40 has an extended head portion 4|.

An insulation disk 42 is secured to head 41 by rivets 43. A retaining ring 44 is secured to shaft 40, against which spring washer 45 presses on dial 20.

Spring washers 31 and 45 thus press dial 20 and plate 35 into firm frictional engagement. Spring washer 45 also biases disk 42 into firm frictional engagement with worm gear 33 through shaft 40. Thus when control knob 11 is rotated, disk 42 is correspondingly directly turned. Despite th'e frictional coupling of disk 42 and worm gear 33, gear 33 remains stationary with dial 2!] when disk 42 is turned, since gear 33 is in engagement with a worm. Also, if dial 20 is manually rotated, it will move with respectto plate 35, which also remains stationary with gear 33. The zero adjustment of dial 20 is readily accomplished by manually turning dial 23 until its zero 0 marking corresponds with the reference marking on the casing.

Insulation disk 42 contains a pin 15 which is engageable with forked ends 14 of cam clevis 16, as shown particularly in Figs. 1 and 2. Clevis 16 is secured to clevis shaft 11, rotatably arranged in bearing 18. The other end of clevis shaft 11 carries switch cam 80, forming part of this invention switch assembly as shown particularly in Fig. 3. Switch cam has a lower triangular shaped portion 8| and an upper circular cam portion 82. Switch cam 80 is arranged between switch units 83 and 84 in such manner as not to press or actuate switch plungers 85 and 86 when in the neutral or central position shown in Fig. 3. The type of switch known in the art as micro-switch is preferred for the switches 83 and 84, wherein the plungers 85 and 86 require only small pressure, and need be depressed only a small distance to effect the switching of comparatively large currents.

A pin 81 projects from cam 80 centrally; above clevis shaft H. A spring post 88 is fastened to fixed plate 90 secured with housing I5 by screw studs 9|. A spring 93 is stretched between pin 81 and spring post 88. Spring 93 produces a toggle action, keeping switch cam 80 in unstable equilibrium in the central neutral position, or displaced to the full right or left positions off center, corresponding with movements imparted to the clevis. Spring 93 stabilizes the action of switch cam 80 against vibration or mechanical shock. Stops 94 and 95 limit the turning of cam clevis 16, as shown in Fig. 2.

Switch units 83 and 84 are provided with springs 91 and 98 respectively. One end of the springs is secured to plate 90. The other ends of springs 91 and 98 are arranged in holes IM and I02 provided in switches 83 and 84. The springs 91, 98 mechanically bias the switches towards cam 80. Adjustable stops I04, I05 limit the inward positions of switches 83, 84 and their corresponding plungers 85, 86. Stops I04, I05 are hexagonal headed screws threaded into bosses I 06--I0"I on plate 90. The setting of heads I04, I05 is adjusted by a suitable wrench, to predetermine the lateral position of plungers 85 and 86 with respect to the periph'eral surface of switch cam 80.

The vertical adjustment of switches 83, 84 is performed by eccentric bushings I08, I09 secured respectively to stud screws IIO, III. Screws IIO, III extend into plate 90. The screws IIO, III and the bushings I08, I09 pass through openings in the switches 84, 85, as indicated in Fig. 4. By rotating adjusting stud screw 0 with bushing I08, switch unit 83 may be correspondingly raised or lowered, for adjusting the position of its plunger 85 vertically with. respect to cam switch 80. Similarly, plunger 86 of switch unit 84 is adjusted by stud and bearing I09, III.

counterclockwise rotation of knob I! through an arc displaces disk 42, turning clevis I8 clockwise through pin I5. Switch cam 80 accordingly is likewise rotated clockwise to cause plunger 86 to be depressed from its normal position to close the circuit of switch 84.

When pointer I8 is manually moved over scale 20 in a clockwise direction causing a counterclockwise rotation of cam clevis I8 and hence of switch cam 80, plunger 85 of switch 84 is thereupon depressed to establish a circuit through this switch. 7

While the switch assembly has, for purposes of illustration, been described in my Patent 2,355,- 381 as incorporated in an antenna control, it is generally applicable to any circuit. Furthermore,

while a, specific embodiment of the invention has' been shown and described in detail to illustrate the applicationof the principles thereof, it will be understood that the invention may be otherwise embodied without departing from such principles.

What is claimed is:

1. An electric switch assembly comprising a base; a pair of switches each having an operatin plunger; individual means pivotally mounting each switch on said base; a cam oscillatably mounted on said base between said switches; said operating plungers engaging opposed surface portions of said cam; such pivotal mounting means comprising individual circular cam means engaging a circular aperture in each switch and eccentrically mounted on a pivot secured to said base; said circular cam means providing for adjustment of said switches with respect to said pivot to substantially align said operating plungers; and

. a pair of springs each having one end engaged with said base and the other end engaged with a switch, said springs urging said switches to ward said cam.

2. An electric switch assembly comprising a base; a pair of switches each having an operating plunger; individual means pivotally mounting each switch on said base; a cam oscillatably mounted on said base between said switches; said operating plungers engaging opposed surface portions of said cam; such pivotal mounting means comprising individual circular cam means engaging acircular aperture in each switch and eccentrically mounted on a pivot secured to said base; said circular cam means providing for adjustment of said switches with respect to said pivot to substantially align said operating plungers; a pair of springs each having one end engaged with said base and the other end engaged with a switch, said springs urging said switches toward said cam; and adjustable means limiting the movement of each switch toward said cam.

3. An electric switch assembly comprising a base; a pair of switches each having an operating plunger; individual means pivotally mounting each switch on said base; a cam oscillatably mounted on said base between said switches; said operating plungers engaging opposed surface portions of said cam; such pivotal mounting means comprising individual circular cam means engaging a circular aperture in eachswitch and eccentrically mounted on a pivot secured to said base; said circular cam means providing for adjustment of said switches with respect to said pivot to substantially align said operating plungers; a pair of U-shaped springs each looped around one of said pivots and each having one end engaged with said 'base and the other and engaged with a switch,- said springs urging said switches toward said cam; and adjustable means limiting the movement of each switch toward said cam.

WILLIAM F. LEAR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 588,428 Heck Aug. 17, 1897 904,906 Wiegand Nov. 24, 1908 2,388,365 Thorp Jan. 4, 1944 2,033,417 Dezotell Mar. 10, 1936 2,094,319 Faust Sept. 28, 1937.