US3811023A

US3811023A - Switch transfer mechanism having idler gear with positioning means permitting the transfer means to be clear of the idler gear after its travel through a predetermined switch position

Info

Publication number: US3811023A
Application number: US00320209A
Authority: US
Inventors: R Andersen
Original assignee: General Precision Industries Ltd
Current assignee: General Precision Industries Ltd
Priority date: 1971-10-28
Filing date: 1973-01-02
Publication date: 1974-05-14
Anticipated expiration: 1991-05-14
Also published as: CA953761A

Abstract

A switch transfer mechanism comprising two or more rotary switches each having a rotatable shaft and a disc secured transversely to each of the shafts. Transfer means are associated with each of the discs and adapted to engage an idler gear during its travel through a predetermined position. The idler gear is in tooth engagement with a further disc of an adjacent shaft to cause the further disc and adjacent shaft to rotate through one switch position. Each of the discs have positioning means associated therewith to releasably retain the rotor shaft in each switch position and to permit the transfer means to be clear of the idler gear after its travel through the predetermined switch position to thereby permit independent clockwise or counterclockwise rotation of the further shaft.

Description

United States Patent 1 1 7 Andersen 22 Filed: Jan. 2, 1973 21 Appl.No.:320,209

Related US, Application Data [62] Division of Ser. No. 194,399,'Nov. l

abandoned.

[52] US. Cl. v200/153 P, 200/14, 200/166 SD, 335/207 [51 Int. Cl. HOlh 3/40, l-I0lh 19/60 [58] Field of Search 200/166 SD, 14, 153 P, 200/11 TC, 11 R; 335/205, 206, 207; 235/103 [56] 1 References Cited UNITED STATES PATENTS Blackman 200/14 [451 May 14, 1974 Primary Examiner-Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye [57] ABSTRACT A switch transfer mechanism comprising two or more rotary switches each having a rotatable shaft and a disc secured transversely to each of the shafts. Transfer means are associated with each of the discs and adapted to engage an idler gear during its travel through a predetermined position. The idler gear is in tooth engagement with a further disc of an adjacent shaft to cause the further disc and adjacent shaft to rotate through one switch position. Each of the discs have positioning means associated therewith to releasably retain the rotor shaft in each switch position and to permit the transfer means to be clear of the idler gear after its travel through the predetermined switch position to thereby permit independent clockwise or counterclockwise rotation'of the further shaft.

5 Claims, 8 Drawing Figures PATENTEnw 14 I974 SHEET 2 0r 3 FIG. 3A

FIG. 3B

PATENTEMY 14 :974

Sam 3 BF 3 RELATED APPLICATIONS This application is a divisional of application Ser. No. 194,399, filed Nov. 1, 1971, now abandoned.

BACKGROUND OF INVENTION 1. Field of the Invention The present invention relates to a magnetically operated switches and more particularly to a magnetically operated rotary reed switch.

- 2. Description of Prior Art A magnetic reed capsule consists of a pair of spring leaves, made of a magnetic material of low residual magnetism, inside a glass envelope filled with an inert gas, generally nitrogen. When a magnetic flux generated either by a permanent magnet or by a coil, runs through the leads, they become magnets of opposite polarity. If the flux is strong enough, the force of magnetic attraction overcomes the mechanical rigidity of the leaves. In these conditions a closed electrical contact is established between the two leaves.

With the capsules operated by a bar of permanent magnet,'the magnet must be placed at a distance at which the flux will be sufficiently strong to close the contacts. Also the capsules must be placed sufficiently apart in order that only one capsule is influenced by the magnetic flux. I

With this arrangement a decade switch, operating as a break-before-make type, would require ten capsules to be placed equally around the circumference of approximately a 2 inch diameter barrel. Such a large diameter is a disadvantage as it would preclude the use of the switch in many applications.

SUMMARY OF INVENTION It is a feature of the present invention to provide a "magnetically operated rotary reed switch utilizing a discs and adapted to engage an idler gear during its travel through a predetermined switch position. The idler gear is in tooth engagement with a further disc of an adjacent shaft to cause the further disc and adjacent shaft to rotate through one switch position. Each of the discs have positioning means associated therewith to releasably retainthe rotor shaft in each switch position and to permit the transfer means to be clear of the idler gear after its travel through the predetermined switch position to thereby permit independent clockwiseor counter-clockwise rotation of the further shaft.

BRIEF DESCRIPTION OF DRAWINGS The invention will now be described with reference to the embodiment as illustratedin the accompanying drawings in which:

FIG. 1 is a side view illustrating the arrangement of the magnets relative to a reed capsule;

FIG. 2 is an end view of the switch of the present invention;

FIG. 3a is a flux distribution characteristic of the main and auxiliary magnets;

FIG. 3b is a flux distribution characteristic of the combination of FIG. 3a;

FIG. 4 is an illustration of the absolute angular displacements for ON-OFF switch positions;

FIG. 5 is an exploded view of a barrel configuration embodiment of the switch;

FIG. 6 is a fragmented view of a transfer mechanism for coupling a gang of switches; and

FIG. 7 is a top view of the transfer mechanism with fragmented parts thereof.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings and more particularly to FIGS. 1 to 4 there is shown the disposition of the magnets and flux characteristics of the magnetically operated rotary reed switch 10, of the present invention. To obtain a switch of this type havinga relatively smaller diameter as compared to prior art switches a new method of operation has been devised. By utilizing magnetic fields of opposite polarity, this diameter can be considerably reduced. The capsule reeds when subjected to a field oflike polarity, will repel each other; when submitted to a field of unlike polarity will attract each other. Suppose that three reed capsules are placed side by side on the periphery of a circumference swept by a rotor, the'longitudinal axis of the capsules sale there is a field ofunlike polarity, whereas under the two outer capsules there is a field oflike polarity. Thus, the center capsule is closed, and the outer ones are open. If the rotor is turned through a predetermined small angle the central field (unlike polarity) moves away from the center capsule and the bordering field (like polarity) moves in, thus causing the center capsule to open immediately. If the rotor is turned still further the central field enters under the bordering capsule causing it to close. Therefore if these fields are very narrow the space between the capsules can be diminished, thereby reducing the overall switch diameter. Such a switch has been devised and is described hereinafter.

Referring to FIGS. 1 and 2, there is shown the arrangement of the

magnets

12 and 13 relative to a plurality of magnetic reed capsules 11. The activating mechanism consists of a main magnet 12 flanked by a pair of auxiliary transverse magnets 13 of polarity as shown in these figures. The

magnets

12 and 13 are mounted on a drum shaped rotor section 14 secured to a rotatable shaft IS. The main magnet 12 is positioned on the periphery of the drum rotor 14 and along its longitudinal axis. The auxiliary magnets are positioned parallel to each other against an end of the drum rotor 14, on each side of the shaft 15, and transverse to the axis of the main magnet 12. Further the auxiliary magnets 13 are aligned to lie equidistantly on each side of the central longitudinal axis of the main magnet 12. In this arrangement, the auxiliary magnets 13 are made to protrude slightly beyond the outer diameter of the drum shaped rotor 14 so as to approach very closely to the leads 16 extending beyond the ends of the glass envelope 17 of thereed capsule 11. The leads 16 each connect to a respective spring leaf contact 18 inside the envelope 17. With this arrangement, the air gap between 'the auxiliary magnets 13 and the reed lead 16 is reduced to a minimum.

When the main magnet 12 is directly under a reed switch 11, it closes the spring leaves 18. As the rotor drum 14 moves from this initial position, one of the auxiliary magnets 13 approaches one of the leads 16 of the reed capsule 1 1 and the air gap decreases. Thus, the flux induced by the south pole of one of the auxiliary magnets 13 in the lead 16 increases very rapidly, overriding the almost unchanging flux due to the north pole of the main magnet 12. The resultant flux finally changes direction, thus both spring leaves 18 become polarized to the same polarity, repelling each other and opening the contact between the leaves 18 of the reed capsule l1.

Referring now to FIG. 3a, there is shown the flux distribution characteristics of the

magnets

12 and 13. Curve 20 shows the flux density of the main magnet 12. Curves 21 and 22 show the flux density of the auxiliary magnets 13 and curve 23 is the resultant of curves 21 and 22.'As can be seen, since the poles of the auxiliary magnets 13, opposite the main magnet 12, are of opposite polarity, their flux density will oppose the flux density 20 of the main magnet 12 to provide a resultant flux density distribution curve as shown at 24 in FIG. 3b. Thus, it can be seen that the resultant flux density 24 has a relatively narrow lobe defining sharp rises thus providing a constricted field whereby the field of the auxiliary magnets will override the field of the main magnet within a relatively small angular displacement of the main magnet from its position directly under the reed capsule 11.

Referring now to FIG. 4, there is illustrated the angles for ON and OFF conditions from some of the various reed capsules 11 positioned about the rotor 14. In the embodiment herein described there are ten such reed capsules 11 positioned about the rotor 14 providing ten switch positions. Table I below illustrates the various angles of the ONT and OFF conditions of each reed capsule and the angles of the absolute ON and OFF conditions. For example, referring to FIG. 4, it can be seen that the ON angle of the center capsule 11 on each side thereof is a, (1 whilst the OFF angle is 360/n +0: 01 where n is the spacing between adjacent reed capsules. The absolute ON angle is 2 a, (that radiant A" immediately below the center capsule) and the absolute OFF angle is 360ln 201 (radiant B).

It is noted that the angles between some of the reed capsules are larger than the average angle. The reason for this is for change over positioning, as described later with reference to the transfer mechanism, when the switches are coupled in a gang configuration.

FIG. 5 illustrates an embodiment of the construction of the rotary reed switch 10. As herein shown, the main magnet 12 and the auxiliary magnets 13 are partly embedded within the drum shape rotor 14. A cylindrical shape stator case 36 secures a plurality of reed capsules 11 equidistantly over its inner periphery. One end of the stator case 36 is closed off and provided with a circular hole 37 to receive and support the rear protruding end of the rotor shaft 15. A stator cover 38 is adapted to retain the rotor 14 within the stator case 36 and also permits the front portion of the rotor shaft 15 to protrude therethrough to provide for the rotor 14 to be turned clockwise or counter-clockwise in the stator case 36. 4

Referring now to FIGS. 6 and 7, there is shown a transfer mechanism for coupling a plurality of magnetic rotary switches 10 in decade. Each decade switch 10, 10' and 10' comprises a set of l0 miniature reed capsules activated by a rotating magnetic field, as hereinabove described, so as to form a single pole, ten-way, break-before-make selector switch. Each of the rotor shafts 15 of each switch 10 is provided with positioning means in the form ofa circular detent plate 40 secured relative of the shaft 15 and having ten circular detent cavities 41 spaced in a circle concentric with the periphery of the detent plate and adapted to receive a ball 42 therein whereby the rotor 14 may be held stationary in any one of ten positions placing the main magnet 12 directly under a reed capsule 11. The detent cavities 41 are equally spaced with the exception of those of the zero digit (changeover position), indicated at A and B, for reasons as will be described later. A ball retaining circular disc 43 is secured to the shaft 15 adjacent the detent plate 40 and is provided with two circular holes 44 positioned on a diameter of the disc and aligned with the cavities 41. A ball 42-is held within a respective one of the holes 44 by means of a flexible circular retaining plate 45 held thereover by two fasteners 46 positioned on a diameter transverse to the diameter aligning the holes 44. A knob 47 is positioned at the end of the shaft 15, in front of a panel 48, to rotate the circular disc 43 and the balls 44 to adjacent detent cavities where their associated reed switches are caused to close. A clear in-line digit readout is given by the use of transparent plastic-skirted knobs 47, with numbers printed therein. The numbers stand out when overlapping a black spot (not shown) in the panel 48.

A transfer mechanism steps up the preceding digit by one when turning through zero. This is achieved by the provision of pins 50 protruding from a surface of the circular disc 43 and adapted to engage with a tooth 51 of an idler pinion gear 52 also in engagement with a toothed circular disc 53 of an adjacent switch 10'. The idler pinion gear 52 is positioned such as to be engaged by the transfer pins 50 only when the pins move through the zero digit angular displacement (change over position). The detent cavities 41 in line with the change-over position, indicated at A and B, are positioned farther apart (approximately 46) than the normal 36 X,l0 digits 360, to permit the pins 50to clear the pinion gear 52 when rotating through the changeover position, whereby clockwise or counter-clockwise rotation of the adjacent switch may be effected independent of switch 10.

A further set of transfer pins 54 protrude from the toothed circular disc 53 of the adjacent switch 10 similarly arranged to engage a further pinion gear 55 associated with a toothed circular disc 56 of a further adjacent switch 10". As is readily apparent further switches may be similarly coupled to provide larger decades.

This mechanism has the advantage over normal counter mechanism switches which are locked and operated from the units wheel only, in that it may be operated in both directions from any of the decade wheels inside the bank and at the same time operate as a normal counter mechanism switch.

The three decade reed switch arrangement was originally conceived for controlling a frequency synthesizer which was part of a rapid-tuning radio receiver system. However, the combination of guide-access and followthrough step-up action opens a wide field of applications in digital control of electronic measuring instruments, such as bridges, potentiometric devices, decade standards, etc.

The shaft of the last digit can be extended at the rear to mount a flywheel or to connect to an electric motor drive. Still further, modifications are possible without departing from the scope of the present invention as broadly defined by the appended claims.

I claim:

l. A switch transfer mechanism comprising two or more rotary switches each having a rotatable shaft, a disc secured transversely to each said shafts, transfer means associated with each said discs and adapted to engage an idler gear during its travel through a predetermined switch position, said idler gear being in tooth engagement with a further disc of an adjacent shaft to cause said further disc and adjacent shaft to rotate through one switch position, each said disc having positioning means associated therewith to releasably retain said rotor shaft in each switch position and to permit said transfer means to be clear of said idler gear after its travel through said predetermined switch position to thereby permit independent clockwise or counterclockwise rotation of said further shaft.

2. A switch transfer mechanism as claimed in claim 1, wherein said transfer means are pins projecting from a surface of each said discs and adapted to engage a tooth of an associated idler gear when said disc is rotated through a predetermined switch position.

3. A switch transfer mechanism as claimed in claim 1, wherein said positioning means comprises a detent plate secured in stationary relationship relative to said rotatable shaft adjacent said disc, a plurality of cavities in'said detent plate positioned on a circular axis concentric to said shaft, each said cavities corresponding to a switch position and adapted to releasably receive a ball therein associated with said adjacent disc whereby said disc and shaft are maintained stationary in each switch position.

4. A switch transfer mechanism as claimed in claim 3, wherein the distance between adjacent cavities corresponding to said predetermined switch position is greater than the distance between the other cavities to permit said transfer means to clear said idler gear.

5. A switch transfer mechanism as claimed in claim 3, wherein there are two of said balls loosely retained in respective circular holes in said disc and positioned on a diametric axis one on each side of said shaft, said balls being held under pressure against said adjacent detent plate by means ofa flexible retaining plate positioned thereover and secured to said disc, said balls being aligned to travel along said circular axis of said detent plate on which are located said cavities.

Claims

1. A switch transfer mechanism comprising two or more rotary switches each having a rotatable shaft, a disc secured transversely to each said shafts, transfer means associated with each said discs and adapted to engage an idler gear during its travel through a predetermined switch position, said idler gear being in tooth engagement with a further disc of an adjacent shaft to cause said further disc and adjacent shaft to rotate through one switch position, each said disc having positioning means associated therewith to releasably retain said rotor shaft in each switch position and to permit said transfer means to be clear of said idler gear after its travel through said predetermined switch position to thereby permit independent clockwise or counter-clockwise rotation of said further shaft.

3. A switch transfer mechanism as claimed in claim 1, wherein said positioning means comprises a detent plate secured in stationary relationship relative to said rotatable shaft adjacent said disc, a plurality of cavities in said detent plate positioned on a circular axis concentric to said shaft, each said cavities corresponding to a switch position and adapted to releasably receive a ball therein associated with said adjacent disc whereby said disc and shaft are maintained stationary in each switch position.

5. A switch transfer mechanism as claimed in claim 3, wherein there are two of said balls loosely retained in respective circular holes in said disc and positioned on a diametric axis one on each side of said shaft, said balls being held under pressure against said adjacent detent plate by means of a flexible retaining plate positioned thereover and secured to said disc, said balls being aligned to travel along said circular axis of said detent plate on which are located said cavities.