US2934704A - Multiple rotary switch circuit - Google Patents

Description

April 26, 1960 J. w. GooTHI-:RTS 2,934,704

MULTIPLE ROTARY swITcH CIRCUIT Filed Aug. 18, 1958 51u/ rami,

' fam/frs' United States Patent O 2,934,104 MULTIPLE ROTARY SWITCH CIRCUIT Jerome W. Gootherts, Redwood City, Calif., assigner to American Radiator & Standard Sanitary Corporation, New York, l\I.Y., a corporation of Delaware Application August 18, 1958, Serial No. 755,793

4 Claims. (Cl. 324-173) 'I'his invention relates to and in general has for its object the provision of a multiple rotary switch circuit whereby the value of a plurality of resistors or functions thereof inserted in the circuit can be successively sampled.

More specifically, the object of this invention is the provision of a circuit of the character above described wherein the m contact points ofthe stator of a rst rotary switch are connected with the n contact points of the stator of a second rotary switch through mn unique circuits; wherein each of said mn circuits includes a resistor to be sampled in series with a rectifier such as a diode; wherein a source of voltage and a current measuring device are connected in series across the two rotary switching arms of the irst and second rotary switches; and wherein means is provided for rotating said switching arms at speeds in the inverse ratio of mm whereby said rotary switches serve successively to close each of said mn unique circuits, and each of the resistors in said circuits can be sampled once during each cycle of operation of the multiple rotary switch circuit.

Still another object of this invention is the provision of a switching system for successively closing mn unique circuits across a first rotary switch provided with m contact points and a second rotary switch provided with n contact points, and which can be substituted for a single rotary switch having mn contact points.

Thel invention possesses other advantageous features, some of which, with the foregoing, will beset forth at length in the following description where .that form of the invention which has been selected for illustration in the drawings accompanying and forming apart of the present specification, is outlined in full. In said drawings, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claims may be embodied in other forms.

Referring to the drawings,

Fig. l is a schematic diagram of a circuit or system embodying the objects of my invention.

Fig. 2 is a time diagram of the circuit or system illustrated in Fig. l showing the differential commutating action of the two rotary switches of my system.

As illustrated in Fig. 1, the objects of my invention have been embodied in a circuit or system including a iirst rotary switch S1 and a second rotary switch S2. Included in the switch S1 is a conventional ring of three equally spaced contact points p1, p2, p3 and a first coaxial switching arm A1 arranged to sweep over said contacts 1, 2, and 3.

Similarly, the second switch S2 includes a stator provided with a ring of four equally spaced contact points q1, q2, qs, and q., and a second coaxial switching arm A2.

Connected in series across the iirst and second switch arms A1 and A2 is a source of voltage V, and a current measun'ng device M, including a resistor Ro in parallelism with a cathode ray oscilloscope CRO.

Connected across the three contact points p1, p2, and p3 and the four contact points q1, q2, q3, and q., are

2,934,704 Patented Apr. 26, 1960 twelve unique circuits C1-C12, respectively including one of the resistors R1R12 to be sampled and each including a rectifier here shown in the form of a diode d. Here is should be noted that twelve circuits are involved for the reason that the three contact points of the first switch can be combined with the four contact points of the second switch in twelve different and distinct ways. More generally stated, m differentv objects or contact points can be combined with n different objects or contact points mn different ways or circuits.

Operatively associated with each of the rotary switching arms A1 and A2, through a gear reduction box G, is a'motor M1 for respectively driving the switching arms A1 and A2 in the inverse ratio of 4:3, or more generally stated, in the inverse'ratio of rz/m where m represents the number of contact points of switch S1 and n represents the number of contact points of switch S2.

As a result of this system, and with the switching arm A1 and A2 initially set so that A1 is in contact with contact point p1, and A2 is in contact with q1, the two switches will serve to sequentially close the circuits C1-C12, each of which, as shown in Fig. l, includes the source of voltage V and the current measuring device M. This then makes it possible to sequentially sample each of the twelve resistors R1-R12, or in the more general case, the mn resistances.

The specific manner in which the two switches S1 and S2 cooperate with each other so successively close the twelve unique circuits C1-C12 is diagrammatically indicated in Fig. 2. From this figure it will be noted that when switch S1 has completed one revolution, switch S2 has completed only three-fourths of a revolution, and that when S1 has completed four revolutions S2 has completed three revolutions, and the system has one cornplete cycle of operation in T seconds and is in a position to repeat the cycle of operation.

The function of the rectiiiers or diodes d is of course to provide for only unidirectional travel of the current passing through the circuits C1-C12 and to thus provid for twelve unique sampling circuits. f

The system here illustrated can be extended to a pair of rotary switches each having any number of contact points m and n, respectively, but here it should be noted that mn unique circuits can be obtained only provided that m and n have no common factor other than the number one. If m and n do have a common factor k, then the number of unique circuits per cycle of operation is reduced to mn/k. One way of insuring that m and n have no co-mmon factor is to let n=m+1.

If S1 has 100 contact points and S2 has 101 contact points, and the cycle time is l/ minute (or the cyclic rate is 100 cycles per minute), then S1 runs at l0l l00=l0,100 r.p.m. and S2 runs at 10,000 rpm., and the total number of resistances R sampled is 10,100. The output of CRO looks like the output of a 10,100 contact switch running at 100 rpm.

The resistors R can of course be replaced by other circuit elements or by Voltage or' current sources without changing the operation of the system, and for this reason the term resistor is here used in a generic sense to cover all such elements.

Finally, it should be noted that the switching arms of the two rotary switches can be driven from a single motor provided with power take-offs of the proper gear ratlos as above described.

I claim:

l. A multiple rotary switch system comprising: a first rotary switch having a first ring of m equally spaced contacts and provided with a first coaxial switch arm arranged to sweep over said iirst ring of m contacts; a second rotary switch having a second ring of n equally spaced contacts and provided with a second coaxial switch arm arranged to sweep over said second ling of n contacts; mn separate circuits connecting said m contacts with said n contacts, each of said mn circuits including a rectier; and rneans for simultaneously rotating said iirst and second switch arms respectively at speeds` in the ratio of nrm.

2. A multiple rotary switch system of the character defined in clairn 1 wherein n and m have no common factor.

3. A multiple rotary switch system comprising: a rst rotary switch having a first ring of m equally spaced contacts and provided with a rst coaxial switch arm arranged to sweep over said rst ring of m contacts; a second rotary switch having a second ring of n equally spaced contacts and provided with a second coaxial switch arm arranged to sweep over said second ring of n contacts; mn unique circuits connecting the m contacts of References Cited in the le of this patent UNITED STATES PATENTS 2,264,623 Dickinson Dec. 2, 1941 2,460,835 Lutz Feb. 8, 1949 2,476,066 Rochester July 12, 1949 2,849,678 Hannon Aug. 26, 1958

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