US3011041A

US3011041A - Precision switch and method of construction

Info

Publication number: US3011041A
Application number: US764367A
Authority: US
Inventors: Bakels Marinus
Original assignee: UNISON PRODUCTS Co Inc
Current assignee: UNISON PRODUCTS Co Inc; UNISON PRODUCTS COMPANY Inc
Priority date: 1958-09-30
Filing date: 1958-09-30
Publication date: 1961-11-28
Anticipated expiration: 1978-11-28

Description

Nov. 28, 1961 I M. BAKELS 3,

' PRECISION SWITCH AND METHOD OF CONSTRUCTION Filed Sept. 50, 1958 La; r7 A 2 56 llllllllllllllllfi:lllllllllllllllllll E IIIIIIIII ATTORNEYS .brush element controlling the end of the impulse.

United States Pat-em O 3,011,841 PRECISION SWITCH AND METHOD OF CONSTRUCTION Marinus Bakels, Clifton, N.J., assignor to Unison Products Company, Inc, Paterson, -N.J., a corporation of New Jersey Filed Sept. 30, 1958, Ser. No. 764,367 6 Claims. (Cl. 200--166) This invention relates in general to rotary precision switches and particularly to a method of constructing rotors and stators therefore having a. plurality of angularly displaced precisely located conductive areas located along annular areas in their respective external and internal peripheries.

Rotary precision switches of the character of which 'this invention is concerned generally include a stationary brush element on the stator or a rotating rotor brush element arranged to contact conductive segments to deliver and receive electrical impulses as the switch rotor is rotated. this character, a greal deal of accuracy is required in the spacing of the conductive segments in either the rotor '01 the stator depending on which is provided with brush contact elements, in order to contain precise delivery of electrical impulses. Such rotary precision instruments are primarily used for electrical control devices such as telemetering equipment in which both the duration and extent of an electrical impulse is used to measure precise information. Variations in the timing of the start and finish of such an impulse within a small amount will create inaccuracies in the devices.

The present invention is directed to a method of assembling both rotors and stators for small size rotary precision switches of the aforementioned character, inwhich segmental conductive portions are formed by precise gear forming methods, which are thereafter placed on insulated discs. At least two discs are used for each of the conductive impulse areas which must be designed. Precise positioning of the conductive areas is achieved by placing two discs having precision cut conductive segment gear teeth thereon in side by side contact and adjustably rotating the disc until the conductive elements are arranged in the desired angular spacing and extent. In such a method, it is necessary to employ two brush contacting elements to contact the segments of a pair of mating discs instead of the usual one. One of the discs with its conductive element gear teeth segments is used to contact a brush element controlling the start of an electrical impulse and the other adjacent disc with its segments is used to contact 21 Thus, by rotating the discs relative to each other when the conductive areas are formed, it is possible to precisely position the conductive impulse areas so that control of the start and end of the electrical impulse timing can be accomplished within very precise angular displacement. Thus,

for example, where it is desired to have sixty evenly spaced conductive areas located at the outer periphery of a rotor, two gears of conductive material are fabricated, each having precisely cut thereon, sixty gear teeth. All of the spaces between the teeth are filled with insulation and the gear teeth are positioned on slotted insulated discs. The discs are then positioned adjacent one another and they are rotated to achieve the exact conductive element spacimpulsing may be obtained by correct positioningof the disc elements in relation to each other rather than by complicated and expensive machining and aligning methods.

Accordingly, it is an object of this invention to provide In the construction of precision switches of Ice 3,011,041

Patented Nov. 28 1961 a method of forming angularly displaced conductive areas for rotary precision switches.

A further object of the invention is to provide a method of aligning a plurality of conductive areas in an annular ring by mounting a gear of conductive material on a slotted plastic disc and mounting a second gear of conductive material on a second slotted plastic disc, wherein each of the gear teeth formed in the gear are made with peripheral teeth areas of lesser peripheral extent than the conductive areas desired, positioningthe discs adjacent each other and aligning the discs to correctly space the conductive areas defined and thereafter securing the discs together.

A further object of the invention is to provide a method of manufacturing rotary precision switches which provides a rugged construction which is simple and economical to make. p

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a transverse section of a rotary precision switch constructed in accordance with the invention;

FIG. 2 is a vertical section taken on the line 22 of FIG. 1;

FIG. 3 is a side elevation of a pair of conductive segment gear tooth elements and mounting discs prior to their encapsulation;

FIG. 4 is a view similar to FIG. 3 but indicating internal conductive segment gear elements;

' element combination;

FIG. 9 is avertical section taken along the line 99 of FIG. 8; and

FIG. 10 is a top plan of the rotor indicated in FIG. 7 with the segments of two gears combined and aligned to form a single conductive area for contact by a two brush element.

Referring to the drawings in particular, the invention as embodied therein includes a precision rotary switch generally designated 10, having a rotor brush block 12 mounted on a shaft 14 for constant rotation thereby.

The rotor brush block 12 contains two sets of brushes generally designated 16 and 18 having brush elements which are biased into contact with annular

conductive areas

20, 22, 24, 26 and 28 of a stator generally desig nated 32.

In the present embodiment, the brush 16 includes a I brush element 34, which is arranged to contact a solid ring of conductive material 36 provided in the annular conductive area 22 0f the stator 32. A solid brush element 38 is connected to the brush element 34 and is arranged to rotate with the rotor 12 in biased contact with an interrupted conductive ring 40 forming the annular conductive area 20 in the stator 32. Similarly,

the brush 18 includes a brush element 42 arranged to contact a solid ring of conductive material 44 in the an nular conductive area 24. A pair of double brush elements 46a, 46b and 48a and 4812 are connected to the element 42. These double brush elements are arranged to contact interrupted conductive element half segments 50 and 52 on the annular conductive areas 26 and 28, respectively. 1

Each of the solid ring conductors, the broken ring elementsrand the conductive segments are connected electrically by lead wires or terminals 54 which extend through an aperture 56' at the end of the precision switch 10.

In accordance with the invention, the stator of such a switch is made in accordance with the following method: Conductive segments 56 and 52 are formed by precision cutting conductive material into a gear or spline form having aprecise number of teeth with a precise spacing therebetween. The gear may be either an external gear as at 56 or an internal gear as at 58. Each of the gears is cut to define

conductive segment portions

60 and 62 for the

gears

56 and 58, respectively, of an internal surface and angular spacing required for precision electrical impulsing. In this instance, the

brush elements

34 and 42 are arranged to receive a constant input electrical impulse from the solid conductive rings 36 and 44 and distribute these pulses through the leads 54 in precise timed relation and duration, as the brush elements 46 and 48 and 38, passthe interrupted conductive segment portions 50 and 52 and 20.

In accordance with the present invention, each of the

gears

56 and 58 are cut to provide

gear teeth

64 and 66, respectively, which have

conductive segment portions

60 and 62 which are of slightly less angular extent and with slightlygreater angular displacement than will be actually required in the annular conductive areas for which they are to be formed. The reason for this is that two such gears are combined to provide one set of full conductive areas such as at 52. In such an instance, a single brush element is replaced by the double brush elements such as 48a and 48b, one of which willcontact a left hand conductive segment 52a and the other of which will contact a right hand conductive segment 52b (FIG. 6).

After the

gears

56 and 58 have been machined, the spaces between the

gear teeth

64 and 66 are filled with an insulating material '78. Regardless of whether an internal or external gear is made, the gears are positioned upon a plastic insulator disc 80 which in the case of the external gear 56 is later cut away to expose the conductive segments 60.

In accordance with the invention, an annular conductive area comprising interrupted conductive segment portions is formed by joining together two similar gears such as the externalgear 56 each mounted on its associated disc 80. Before the set of disc and gear assemblies are fixed together they are adjusted angularly by rotating one gear with its associated segment to precisely locate a surface 82 for electrical impulse start and a surface 84 for electrical impulse termination.

Thus, the previous method of precisely finishing the segment portions filling in with plastic, calibrating the spacing and then refinishing and refilling with plastic and conductive material by hand can be obviated.

Within the limits of the sizes of the gear teeth 64 which are cut, the gears may be rotated to obtain precise positioning between a left hand portion gear segment 52a and a right hand portion gear segment 52b. The discs 80 are thenset in relation to each other by a set screw 90 which is positioned through an arcuate slot 92 and tightly secured. The faces of the disc 80 are recessed as at 94 to permit the securing of plastic disc spacer member brush thereto to form the remaining portion of the stator.

In the case of the external gear 56 after two gears have been joined together and a precise positioning of the segment portions 52a and 522) has been achieved by rotating the assemblies, the segments are connected individually to the lead wires 54. The lead wires are then potted in a heat setting plastic 95 which is allowed to set up and harden. Thereafter, the discs 30 are removed from the center of the gears 56 and a rim 96 of the gear is cut away until the plastic 78 is reached and the segments 66 are accurately defined.

In the case of the internal gear 58, it is necessary to cutaway a rim 98 before the leads 54 are connected to the individual segments. Thereafter, the disc 80 is cut away and the interior bore is accurately machined to clearly define the segments 62 which will be arranged along the inner annular periphery of the stator.

The invention is equally applicable to the manufacture of rotors having interrupted annular conductive areas formed thereon, such as illustrated in FIGS. 7 to 10 inelusive. The rotor generally designated 100 includes a plastic hubbed sleeve 102, upon which is positioned a metallic bushing 104 which carries a solid ring conductor 106 and an interrupted segmental ring conductor gen erally designated 108.

The interrupted segmental ring conductor is formed in accordance with the invention by first forming an external gear 110 with the precise number of gear teeth 112 to give the desired number of segmental conductive areas. The gear teeth 112 are made smaller, and with a spacing larger, than will be actually required. The spaces between the teeth are filled with heat setting plastic insulation 114 and the gear is mounted on a plastic disc 116 having an arcuate slot 117. When two such assemblies are made and they are positioned into close engagement (FIG. 9), the disc assemblies are then rotated until the desired conductive areas from a starting peripheral contact line 118 of the left gear disc assembly and a finish peripheral contact line 120 of a right gear disc assembly to thus define the correct conductive area angular extent (FIG. 9).

Once the assemblies are accurately aligned they are held in position by a set screw 122 which is positioned in the slot 117. Each disc 116 is suitably recessed at 124 to provide clearance for the screw heads on each side and permit close fitting of a plurality of assemblies. In the operation of such a rotor two laterally spaced brush elements for each conductive area are required to sweep around the rotor periphery, one in contact with 'each segment instead of the usual one. Electrical contact is made by one brush and stopped by the other since the conductive areas are angularly displaced.

Thus the invention provides a simple means for the precision making of small diameter rotary switches. It is possible with the invention, by making up a plurality of discs with interrupted segmental conductive areas thereon of varying angular extent and angular spacing to achieve any electrical impulsing desired by uniting a plurality thereof to form the desired conductive areas. Use of either two, three or even four brush elements in conjunction with two or more joined disc segments may be used to give any electrical impulse timing and extentrequired in a rotary switch. The invention greatly simplifies the construction of such switches and reduces the time for the assembly thereof as well as greatly increases the accuracy thereof.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

I claim:

1. A precision switch rotor having at least one peripheral annular electrically conductive area comprising spaced conductive segments interrupted by insulation wherein said conductive area includes at least two conductive material gear like elements having a plurality of teeth corresponding in number to the desired number of conductive segments but angularly spaced a slightly greater amount than the segments which are formed thereby, said elements being positioned on side by side touching electrical engagement but with the teeth thereof offset a precise amount to define the beginning of each conductive segment by the forward edge of the gear of one element, and the end of each conductive segment by the trailing edge of the gear of another segment.

2. A rotor according to claim 1 wherein said gear like elements are at least two gears having a plurality of angularly spaced teeth each having flat peripheral portions defining conductive areas. I i

3; A precision switch rotor having at least one peripheral annular electrically conductive area comprising spaced conductive segments interrupted by insulation wherein said conductive area includes at least two conductive material gear like elements formed from an external gear having a plurality of teeth corresponding in number to the desired number of conductive segments but angularly spaced a slightly greater amount than the segments which are formed thereby, said elements being positioned on side by side touching electrical engagement but with the teeth thereof oflset a precise amount to define the beginning of each conductive segment by the forward edge of the gear of one element, and the end of each conductive segment by the trailing edge of the gear of another element. 9

4. A precision switch stator having at least one internal annular electrically conductive area comprising spaced conductive segments interrupted by insulation wherein said conductive area includes at least two conductive material gear like elements having a plurality of teeth cor responding in number to the desired number of conduc: tive segments but angularly spaced a slightly greater amount than the segments which are formed thereby,

6 said elements being positioned on side by side touching electrical engagement but with the teeth thereof offset a precise amount to define the beginning of each conductive segment by the forward edge of the gear of one element, and the end of each conductive segment by the trailing edge of the gear of another element 5. A stator according to claim 4 wherein said gear like elements are at least two internal gears having a plurality of angularly spaced teeth eachhaving flat internal peripheral portions defining conductive areas.

6. A precision switch stator having at least one internal annular electrically conductive area comprising spaced conductive segments interrupted by insulation wherein said conductive area includes at least two conductive material external gears having a plurality of teeth corresponding in number to the desired number of conductive segments but angularly spaced a slightly greater amount than the segments which are formed thereby, said elements being positioned on side by side touching electrical engagement but with the teeth thereof offset a precise amount todefine the beginning of each conductive segment by the forward edge of the gear of one element, and the end of each conductive segment by the trailing edge of the gear of another element, conductive leads connecting each of said gears, and insulation encasing said gears and said leads, the interior rim of said external gear being cut away to expose the inner ends of said gears.

References Cited in the file of this patent UNITED STATES PATENTS 2,133,980 Fowlor Oct. 25, 1938 2,681,393 Hopkins June 15, 1954 2,749,397 Brown June 5, 1956 2,825,960 Protz Mar. 11, 1958 2,832,127 Felts Apr. 29, 1958 2,853,563 Bole Sept. 23, 1958