US2539347A - Fuel selector switch - Google Patents

Description

C. H. FLUBACKER FUEL SELECTOR SWITCH Jan. 23, 1951 2 Sheets-Sheet 1 Filed June 26, 1947 INVENTOR (72a rles 5V. Flzzbacker Jan. 23, 1951 c. H. FLUBACKER FUEL SELECTOR SWITCH 2 Sheets-Sheet 2 Filed June 26, 1947 JNVENTOR. C/zarles flf/ubacker L14. I flit fatented Jan. 23, 1951 UNITED STATES PATENT OFFICE FUEL SELECTOR SWITCH Charles H. Flubacker, Chicago, Ill assignor to (Jock Electric Company, Chicagm-IIL; a -corporation of lllinois Application June 26, 1947, Serial No. 757141 (01. zoo-+18) Claims. 1

The present invention relates to a selector switch and has special reference to a selector switch which will be absolutely accurate and positive acting at all times. More particularly this invention relates to fuel selector switches such, for example, as may be employed on airplanes for actuating solenoid discharge valves associated with the fuel tanks thereof.

In airplanes it is customary to have from two to'six or even more gasoline tanks with solenoid valves for'controlling'the discharge of gasoline therefrom. In operation, gasoline for all the engines is supplied from one fuel tank at a time. When one tank is substantially empty, or if for any other reason it is desired to procure gasoline from another tank, the selector switch is manually set to a position'which will'efiect closing of the solenoid valve in the fuel tank then supplying gasoline and opening the solenoid valve of another tank.

Obviously, it is essential to the safe operation of a plane that the selector switch be absolutely accurate so the pilot may know the condition of the fuel tank'discharge valves at all times. It is, therefore, an object of the present invention to supply a fuel selector valve which will be absolutely accurate at all times.

In the construction and assembly of the fuel selector switch the various parts are soformed that they can be assembled only in a particular relationship. The selector switch preferably comprises a base plate having provision for securing thereon a plurality'of relatively small circuit closing contact devices or switches equal in number to the number of fuel tanks of the plane in which it is to be used. Irrespective of thenumher of such contact devices in a selector switch, the same base plate may be employed as it has provision for securing any required number in substantially uniformly spaced arrangement sim ilarly'positioned'about thecenter-of the plate.

A camshaft extends through the center of the base plate and has fixed thereon a cam with a projecting portion for actuating the circuit closing contact devices. overlying the base plate and switches is a cover which is'constructecl for being secured to the base plate in only one relative position. The exposed face of the cover is provided with a dial having indicia thereon representing each of the circuit closing devices em"- ployed in the selector switch and similarly positioned. The dial is so constructed that it can be secured on the cover in only one position relative thereto.

The camshaft extends through the center of the cover and dial and has fixedly mounted thereon adja'centthe dial, an indicator. Means are provided for fixedly securing the indicator on the'camshaft in a particular predetermined position relative to the cam projecting portion so that the. position of said indicator with respect to said dial accurately indicates the position of said cam projecting portion with respect to' said contact I devices.

Withthe present construction, not only is the fuel selector switch absolutely accurate but switches having from two to six or more circuit closing contact devices may be assembled from a rninimum of different parts. The only single element which varies is the dial as the markings thereon differ'in accordance with the number of circuit closing contact devices employed.

Another object, therefore, of the present invention is'to provide fuel selector switches for use in planes having'different numbers of fuel tanks therein'which may be produced from a minimum number of parts and can be assembled only in a particular manner that will assure operation of the accurate selector switches.

Further objects and features of this invention will be apparent from thejfollowing description and claims when considered in connection with the drawings in which: I

Figure 1 is a perspective view of a selector switch embodying the presentinvention intended for controlling theoperation of six different valves; I

Fig; 2 is a top plan View thereof with the front cover removed;

Fig. 3 is a top plan view of the-base plate employed in the various switches;

Fig. l'is a side elevation view of aselector switch illustrated in Fig. l

Fig.5 is a central vertical cross-sectional view of the switch shown in' Fig; 4;

Fig. 6 is a diagrammatic view of a selector switch connectedto the "solenoid'valves associated with six fuel tanks;

Fig. 'T is a'diagra'minatic view of a selector switch connected to the'solenoid valves associated with four fuel tanks;

Fig.8 is a view similar to Fig. 2 with the-wires removed showing the arrangement when six circuit closing contacts are employed in a switch;

Fig.9 is a top plan view of the switch shown in Fig. 8;

Fig. 10 is a viewsimilar to Fig. 8 showing the arrangement of the circuit closing contact devices when four'are used 'in the-selector switch;

Fig. 11 is a top plan view-of the switch shown in Fig. 10;

Fig. 12 isa diagrammatic view of a selector switch connected to the solenoid valves associated with two fuel tanks;

Fig. 13 is a view similar to Fig. 8 showing the arrangement of the circuit closing contact devices when only two are employed; and

Fig. 14 is a top plan view of a selector switch shown in Fig. 13.

Referring to the drawings and more particularly to Figures 1 through 5, there is shown a selector switch embodying the present invention intended for controlling solenoid valves in a fuel supply system including six fuel tanks. The selector switch may comprise a base plate I having formed therein a plurality of tapped openings arranged about the center thereof for receiving securing means for mounting thereon a plurality of circuit closing contact devices or small switches such as are commonly designated microswitches.

The tapped holes in the base plate l0 may be arranged in two circles about the center of the plate, those in one circle receiving the securing means adjacent one end of the small switches. and those in the other circle receiving the securing means adjacent the opposite ends of the small switches.

As the base plate It! is designed for use in selector switches for controlling a plurality of fuel tank discharge valves, which number may vary, such as from two to six thereof, the tapped holes in the base plate are arranged for receiving the securing means of from two 'to six small switches or contact devices. Consequently, six tapped holes ll, l2, l3, I4, l5, and I6 are arranged in the outer circle 60 degrees apart and the 00- operating tapped holes l1, l8, I9, 20, 2|, and 22 in the inner circle are also 60 degrees apart.

In the particular form of small switch or contact member 23 illustrated in connection with the present invention, the securing screws 24 are at diametrically opposed corners thereof. Consequently, when six of the small contact devices are employed one will be secured by the tapped holes ii and 22, the second by the holes l2 and H, the third by the holes I3 and I8, the fourth by the holes I4 and I9, the fifth by the holes [5 and 2c, and the sixth by the holes l6 and 2i.

When six of the contact switches are employed with the screws 24 secured in the tapped openings in the base plate l0 they will be arranged as shown in Fig. 2. The switches or contact devices are uniformly spaced and similarly arranged about the center of the base plate. If only two contact devices are employed, as illustrated in Fig. 13, the tapped openings l l and 22 may be employed to secure one of the contact devices, and the tapped openings I4 and I9 would secure the opposite contact devices. Moreover, if three contact devices are employed in the switch, the tapped openings H and 22, I3 and I8, and i5 and 20 would be utilized.

When four small switches or contact devices are to be employed the tapped openings H and 22 and M and l9 would be employed the same as when only two such devices are thereby secured to the base plate. In addition, tapped openings 25 and 26 would be formed in opposite sides of the outer circle midway between the openings II and I4, and tapped openings 21 and 28 would be formed in opposite sides of the inner circle midway between the openings I 9 and 22. The four contact devices secured by these openings will be 90 degrees apart.

As it may alsobe desirable to employ five of the microswitches, holes spaced '72 degrees apart around the inner and outer circles are required. In addition to the tapped hole H there would also be formed in the outer circle tapped holes 29, 30, 3|, and 32 which would co-operate for securing the five switches with the tapped openings on the inner circle, 33, 34, 35, and 36 respectively. Thus a single base plate having tapped openings as above described or other similarly arranged securing means may be used in various selector switches with from two to six small switches or contact devices. If more than six of these small switches are to be employed, as might be desirable in some instances, additional tapped openings therefor would be formed and the base plate would have to be larger to accommodate this large number of devices.

The base plate Ill is provided with a central opening 37 through which a camshaft 38 extends and projects a distance on each side thereof. Positioned in the opening 37 is a bushing 39 having an enlarged end portion Ailwhich abuts the front or upper face of the base plate NJ, as viewed in Fig. 5. The opposite end of the bushing on the other side of the base plate is externally threaded for receiving a nut 4i. Tightening of the nut 4i securely clamps the base plate between the nut il and enlarged head 40. A collar 42 fixed to the camshaft 38 by a nut 43 abuts the nut ll thereby serving to limit longitudinal movement of the camshaft 38 outwardly or forwardly. Integrally formed with the camshaft 38 is a cam 44 positioned to abut the outer or upper face of the enlarged bushing end MI. This construction, while permitting rotation of the camshaft in the base plate ll] prevents longitudinal displacement of said shaft.

Cam 44 preferably is circular in shape with a narrow projecting portion 45 extending radially thereof, and the periphery of the cam is shaped to provide a somewhat gradual approach to the outer face of the projecting portion.

As the cam 44 is spaced a distance from the outer face of the base plate It], spacing studs 46 are provided for supporting the small switches 23 in front of the plate H]. The studs 46 are provided at one end with a threaded portion 41 for being screwed into the tapped openings in the base plate and the other end is tapped for receiving the securing screws 24 of the small switches. Consequently, when the small switches have been attached to the baze plate they will be spaced therefrom as shown in Fig. 5.

These small switches are preferably of the spring actuated snap type normally biased to open position. An actuating plunger 4 8 associated with one of the contacts projects from one side of the switch casing, and when moved inwardly closes the contacts. The position of the switches is such that the plungers G8 extend toward the cam. With the contacts in open position, as shown by the switch 23 to the left in Fig. 5, the plungers 38 will just contact or lie adjacent the circular portion of the cam periphery. However, when, due to rotation of the cam 44, the projection 35 engages a plunger G8 the latter will be forced inwardly and close the contacts, as is illustrated by the small switch 23 at the right in Fig. 5. By properly positioning the cam 45 with respect to the plungers of the small switches 23 each of them may be closed one at a time, or all of them may be open.

Conductors 49 which extend through openings provided therefor in the base plate Ill con nect each of the small switches in circuit with a corresponding solenoid valve 50 associated with a fuel tank such as employed in airplanes. The solenoid valves are preferably of the usual type, biased to closed position and moved to open position upon energization of the solenoids of the valves. Therefore, movement of the cam 44 in a. complete rotation will successively open and close each of the solenoid valves for the fuel tanks.

It is'essential that the pilot or other operator of the selector switch embodying the present invention know definitely the position of the cam projection 45 with respect to the various plungers 48 of the small switches and thereby the condition of the solenoid valves associated with each of the fuel tanks. This in turn necessitates absolute accuracy in the assembling of the completed selector switch.

For this purpose the various parts going to make up the completed selector switch are formed and arranged so that when assembled they necessarily will be in a particular predetermined arrangement. A front cover 5i is positioned over the small switches 23 and cam 44 having a central opening to permit the end of the camshaft 38 to extend therethrough. On

the outer base of the cover 5| there is a dial 52, different dials being illustrated in Figs. 1, 11, and 14. For the purpose of securing cover 5| on the base plate i5, tapped holes 53 are formed in the base plate adjacent the periphery thereof, the spacing between the holes being nonuniform so that if only three holes are used, as illustrated, the distance between one combination of two of them is greater than the distance between another'combination of two of the tapped holes. Studs 54, tapped at one end and externally threaded at the other, are secured in these openings in the base plate. Similarly arranged openings are formed in the over 5! so that the openings in the cover will match the openings in the base plate or the tapped studs 54 when the cover 51 is in a particular position with respect to the base plate. Screws may be employed for securing the cover 5! in such position.

On the outer end of the camshaft 38 there is secured a pointer or indicator 55 designed to co-operate with the dial 52, as hereinafter explained. The indicator 55 is formed with a split collar portion 56 to permit its being inserted over the end of the camshaft. A screw 5'! may be employed for pulling the ends of the split collar together to clamp the camshaft tightly therebetween. However, in order to insure that the indictor will be secured on the camshaft in a particular predetermined position with respect to the position of the cam projecting portion 45, the camshaft is preferably provided with a tapped opening for receiving a setscrew 58 extending through the ring of the indicator 55. Obviously the tapped opening in the camshaft would have to be in a particular predetermined position with respect to the cam projection 45.

The dial 52 used in any switch will depend upon the number of small switches employed therein. A dial for use with a selector switch having six of the small switches is shown in Figs. l and 9. In Fig. 11 the dial to be used with a switch having four small switches is illustrated, and in Fig. 14 the dial is for use with a selector Switch having only two small switches. Indicia appearing upon the face of the dial represents the number and arrangement of the small switches. Thus, as shown in Figs. 1 and 9, if six 6. small switches are employed numbers 1 to 6, spaced 60 degrees apart, appear on the dial. For four switches, four numbers degrees apart/ are used, and with two switches, two numbers degrees apart, are marked. In each case the marks are spaced the same as the small switches.

The dial 52 may be securel to the cover 5| by means of screws 59 passing through openings in the dial and threading into matching openings in the cover 5!. The matching openings in the dial and cover are nonuniformly spaced so that the dial may be secured on the cover in only one particular predetermined position with re spect thereto.

Due to the particular arrangement of the ele ments going to makeup the selector switch as above described, the position of the indicator 55 with respect to the dial 5-2 will accuratelyindicate the position of the cam projecting portion 45 with respect to the small switches and more specifically with respect to the plungers-" lfi thereof. When the pointer is directed toward the numeral 1, the operatorwill be assured that the solenoid valve for tank No. 1 will be open. The same is true when the pointer is directed toward the other indicia appearing on the face of the dial.

Moreover, in making up various switches having from two to six or even more small contact devices therein, the elements employed maybe identical except for the dial, thus requiring a relatively small number of parts for original construction or replacement and greatly'reducingthe manufacturing cost thereof.

Spacing studs 68 arranged on the rear or bottom side of the base plate It are threaded into openings provided therefor in said base plate. A rear plate 5! having a central opening 62 is secured tothe Outer ends of the studs Bil. A bushing 63 is secured to the back plate 5i and the camshaft 38 extends therethrough. Additional bushings 64 are secured in openings in the back plate 6| on each side of the central opening 6-2. A rear cover plate 55 having openings therein for the ends of the bushings 64 and the camshaft to pass through is secured to the rear side of the base plate l0 and overlies the back plate 6i.

Theconnections between the small switches of the selector switch and the solenoid valves in the fuel supply system are shown particularly in Figs. 6, '7, and 12.

A pair of conductors 49 runs from each pair of contacts of a small switch through openings in the base plate Ill and out through the bushings 64 to the contacts of the solenoid switches 50, there being one such solenoid switch for each fuel tank. In Fig. 12 two pairs of conductors 49 connect the small switches 23 to the so enoid valves controlling the'disc'harge of fuel from each of the fuel tanks 66.

Fig. 7 is similar to Fig. 12 except that small switches are used in the selector switch and are connected by pairs of conductors 49 to the four corresponding solenoid valves 5!} connected to the four fuel tanks 66.

In Fig. 6, three pairs of conductors 49 pass through each of the bushings 64 and connect the six small switches to their respective solenoid valves 50 of the fuel tanks 66.

With this construction, whenever a small switch is closed by action of the cam projection on the plunger of the switch the solenoid valve controlled thereby is opened permitting the flow of fuel from the fuel tank therethrough.

While l have shown and described the particular embodiments of the present invention intended primarily for use with fuel tanks on planes, it is to be understood that the invention is not limited thereto but may be used for operating other electrically actuated devices and having various modifications therein without departing from the present invention.

What is claimed is:

1. A selector switch comprising a base plate, a rotatable cam with a projecting portion thereon mounted centrally of said base plate, said base plate having provision for receiving thereon from two to six or more substantially uniformly spaced circuit closing contact devices similarly arranged about the axis of rotation of said cam in positions to be actuated thereby, a cover for said base and contact devices, said plate and said cover having provision for mounting said cover in a single particular predetermined position with respect to said plate, a dial having indicia thereon representing each circuit closing device on said base and similarly positioned, said cover and said dial having provision for fixing said dial to said cover in a single particular predetermined position, an indicator adjacent said dial associated with said cam, said indicator having provision for being secured in a single predetermined position relative to said cam projecting portion, said elements being so arranged that the position of said indicator with respect to said dial accurately indicates the position of said cam projecting portion with respect to said contact devices.

2. A selector switch comprising a base plate, a rotatable camshaft extending centrally through said plate having fixed thereon a cam with a projecting portion, said base having provision for securing thereon from two to six or more substantially uniformly spaced circuit closing contact devices arranged about said shaft and positioned to be actuated by said cam projecting portion during rotation thereof, a cover for said base and contact devices, said base also having a plurality of nonuniformly arranged openings and said cover having openings positioned to match said plate openings when said cover is in a single particular predetermined position with respect to said plate, securing means for being positioned in said openings, a dial arranged to be mounted on said cover in a single particular predetermined position, and an indicator having provision for being secured in a single predetermined position on said camshaft such that the position of said indicator with respect to said dial accurately indicates the position of said cam projecting portion with respect to said contact devices.

3. A selector switch comprising a base plate, a rotatable camshaft extending centrally through said plate having fixed thereon a cam with a projecting portion, said base having provision for securing thereon from two to six or more substantially uniformly spaced circuit closing contact devices arranged about said shaft and positioned to be actuated by said cam projecting portion during rotation thereof, a cover for said base and contact devices, said base also having a plurality of nonuniformly arranged openings and said cover having openings positioned to match said plate openings when said cover is in a single particular predetermined position with respect to said plate, securing means for being positioned in said openings, a dial arranged to be mounted on said cover having indicia thereon representing each of said circuit closing contact devices and similarly arranged, said dial having a phi-1 rality of nonuniformly arranged openings therein, and said cover having openings matching those in said dial when said dial is in a single particular predetermined position with respect to said cover, securing means for being positioned in said last mentioned matching openings, and an indicator having provision for being secured in a single predetermined position on said camshaft such that the position of said indicator with respect to said dial accurately indicates the position of said cam projecting portion with re spect to said contact devices.

4. A selector switch comprising a base plate, a rotatable camshaft extending centrally through said plate having fixed thereon a cam with a projecting portion, said base having provision for securing thereon from two to six or more sub stantially uniformly spaced circuit closing contact devices arranged about said shaft and posi-- tioned to be actuated by said cam projecting portion during rotation thereof, a cover for said base and contact devices, said base also having a plurality of nonuniforrnly arranged openings and said cover having openings positioned to match said plate openings when said cover is in a single particular predetermined position with respect to said plate, securing means for being positioned in said openings, a dial mounted on said cover having indicia thereon representing each of said circuit closing contact devices and similarly arranged, said dial having a plurality of nonuniformly arranged openings therein, and said cover having openings matching those in said dial when said dial is in a single particular predetermined position with respect to said cover, securing means for being positioned in said last mentioned matching openings, an indicator mounted on said camshaft adjacent said dial, positioning means associated with said camshaft, and positioning means associated with said indicator cooperating with said shaft positioning means to maintain said indicator in such posi-' tion with respect to said cam that the position of said indicator with respect to the dial will accurately indicate the position of said cam pro jectin portion with respect to said contact devices.

5. A selector switch comprising a base plate,

a rotatable camshaft extending centrally through said plate having fixed thereon a cam with a projecting portion, said base having apertures formed therein for securing thereon a plurality of circuit closing contact devices each having a plurality of securing means, said openings being so positioned that two or more evenly spaced contact devices may be secured on said plate about said cam in positions to be actuated thereby, a cover for said base and contact devices, said base also having a plurality of nonuniformly arranged openings and said cover having openings positioned to match said last mentioned plate openings when said cover is in a single particular predetermined position with respect to said plate, securing means for being positioned in said openings, a dial mounted on said cover having indicia thereon representing each of said circuit closing contact devices and similarly arranged, said dial having a plurality of nonuniformly arranged openings therein and said cover having openings matching those in said dial when said dial is in a single particular predetermined position with respect to said cover, means for securing said dial to said cover, an indicator mounted on said camshaft adjacent said dial, said camshaft and said indicator having cooperating positioning means for maintaining said indicator in such position with respect to said cam that the position of said indicator with respect to the dial will accurately indicate the position of said cam proj ecting portion with respect to said contact devices.

CHARLES H. FLUBACKER.

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

Number 10 UNITED STATES PATENTS Name Date Thomas Feb. 23, 1915 Lloyd Mar, 19, I929 Tuttle Apr. 2'7, 1943 Cofiman Dec. 5, 1944

Images