GB1566240A

GB1566240A - Adjustable stop for rotary electric switches

Info

Publication number: GB1566240A
Application number: GB936278A
Authority: GB
Original assignee: FEME
Current assignee: FEME
Priority date: 1977-03-24
Filing date: 1978-03-09
Publication date: 1980-04-30
Also published as: DE2810362A1; DE2810362C2; IT1080340B; FR2385207B1; FR2385207A1

Description

(54) ADJUSTABLE STOP FOR ROTARY ELECTRIC SWITCHES (71) We, F.E.M.E. Fabbrica Equi paggiamenti Meccanico Elettrici S.p.A. of Viale Certosa, 1-20149 Milano, Italy, a Corporation organized under Italian Law, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statament:-- The present invention relates to a rotary electric switch having an adjustable stop.

Adjustable stops provided in rotary electric switches of conventional type are normally formed by a plurality of axially disposed slots distributed around the circumference in a number corresponding to the positions of the detent cam af the switch, into one of which a stop member is inserted for engagement with a pin projecting radially from the rotor, so as to cause the stopping thereof after rotation past the number of tents corresponding to the position of the slot in which the stop is inserted. The variation of the stopping position of the rotor is obtained by extracting the stop from one slot and inserting it into another slot corresponding to the desired new position.

Adjustable stops produced in this manner have various disadvantages, and in particular, the switch cannot be made hermetic by a seal on its front surface mounted on a panel, due to the presence of the slots. Further, the switch, which in general is mounted axially, must be dismantled from the panel in order to vary the stopping position of the rotor, since this operation involves an axial movewent for removing and returning the particular stop.

The adjustable stop for rotary electric switches, the object of the present invention seeks to avoid the above-mentioned disadvantages of conventional devices, and in particular makes it possible to obtain a sealed installation of the rotary switch on the mounting panel and to effect the adjustment of the stop of the rotating shaft without dismantling the switch from the panel.

According to the present invention there is provided a rotary electric switch having an adjustable stop, comprising a first member mounted co-axially to the shaft of the rotor of the switch and rotatable relative to said shaft in the circumferential direction, and provided with a stop member engageable by a pin of the rotor, to provide an end stop for the rotor and means for enabling adjustment of the position of said stop member relative to the rotor, in order to produce the adjustment of the stop position of the rotor, said first member being lockable in position by means of a second, toothed, member co-operating with the first member, said second member being displaceable in a radial direction through a slot formed in the body of the switch.

In greater detail, the first member is preferably formed by an annular disc provided with a series of radial incisions, distributed around the peripheral edge and in number corresponding to the positions of the detent cam of the rotor, and having a tooth projecting from the disc as the stop member. The disc may be mounted loosely and co-axially to the shaft within the switch, and the slots act as means for enabling positioning of the stop member relative to the detent positions of the rotor in order to obtain the adjustment of the stopping position thereof.

The second member is preferably formed by a flat plate provided with teeth and insertable in one of the slots of the disc in order to lock it in a predetermined position, and mounted in a radial slot formed in the body of the switch. The plate is preferably arranged co-planar with the disc and removable from outside for disengaging the disc and permitting the adjustment thereof in the ciSum- ferential direction. The projecting tooth of the disc may therefore assume as many positions as there are detent positions of the rotor, by the rotation of the disc.

In order to make the coupling between the tooth of the plate and each of the incisions of the disc more efficient, the flanks of one of the two components are preferably so formed as to eliminate any radial play.

The radial slot provided in the body of the switch is preferably provided in a moulded component of thermoplastic material, and has the four radiused corners in order to ensure rhe necessary frictional engagement of the plate during the removal or insertion of the plate in the slot.

The projecting tooth of the disc engaging with the pin of the rotor, itself of conventional type, limits the rotation thereof in one direction, whilst in the other direction the rotation of the shaft is limited - in conventional man ner - by a fixed stop, connected to the Fluxed part of the switch which engages with the same pin of the rotor.

The adjustment of the stopping position of the rotor, after the number of detent rotations of the rotor predetermined by the user, is effected by removing the plate from the radial slot, rotating the displaceable disc in the desired direction, and then reinserting the plate in order to lock the disc in the new position.

If the rotation of the disc has to be effected to adjust an increase in the number of detent rotations, i.e. the positions of the rotor, it is sufficient to rotate the rotor of the switch which, by means of its pin, also causes the disc to rotate. If, however, the rotation is in a direction for decreasing possible switch positions, it is necessary to rotate the disc by means of any desired tool or other device, operating through the slot in the body of the switch, in order to bring said slot to the starting position and then to rotate it in the opposite direction, by means of the rotor of the switch, as in the preceding case until the desired position is reached.

In order to faciIitate disengagement, the plate may be provided with a hole in which the tip of a tool can be inserted and a notch formed on the slot in which the tool can act as a lever. The described adjustable stop is provided with an external radial slot located on the side surface of the switch and only needs radial movements to permit the sealing of the switch by means of a gasket on its front surface resting against the panel and to permit a variation in the stopping position of the shaft without dismantling the switch from the panel.

The present invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section of a rotary switch provided with an adjustable stop, according to the present invention, and mounted on a panel; Fig. 2 is a cross-section taken on the line 11-11 of Fig. 1; Fig. 3 is a cross-section taken on the line lIr-IlI of Fig. 1; Fig. 4 shows a locking plate, in a view according to Fig. 3; and Fig. 5 shows a section taken on the line V-V of Fig. 3, illustrating the release system of the adjustable stop.

The rotary switch, shown on an enlarged scale in the Figures has a stainless steel control shaft 1 on which there are mounted an axial stop ring 2, an internal rubber gasket 3, two positioning spheres 4, a compression spring 5 (shown in Fig. 2), a stop pin 6 and two rotors 7 of thermo-plastic material. Located on each rotor 7 is a displaceable sweep contact 8 of silver gilt, placed under pressure by a wire spring 9.

The shaft 1 rotates in a bush 10 of nickelplated brass having a threaded outer end and carrying on its front surface an external rubber gasket 11. The bush 10 is secured to a panel 12 by means of a washer 13 and a nut 14. Mounted on the bush 10 and connected thereto by means of three rods 15 (shown in Figs. 2 and 3) is a small plate 16 of thermoplastic material, two sectors of thermo-setting material 17, complete with silver gilt rocker contacts 18, two sectors 19 of thermo-setting material, complete with silver gilt distributor contacts 20 and a clothing flange 21 of thermo-setting material.

A detent cam 22 of hardened steel is provided locked in a fixed position between the bush 10 and the small plate 16, which cam 22 is provided with twelve seats for the spheres 4 and has a tooth 23 acting as an end stop for the pin 6, as shown in Figs. 2 and 3, and hence represents the limit of rotation of the shaft 1 in the anti-clockwise direction.

A displaceable disc 24 of steel is mounted between the shaft and the bottom of the small plate 16, which disc 24 is co-axial with the shaft I and can rotate, guided by the edge of the plate 16. The disc 24 is provided with twelve incisions 25 (shown in Fig. 3) and a tooth 26. This tooth 26 engages the pin 6 after five detent clicks of the shaft 1 and hence represents the end stop of the shaft 1 in the clockwise direction of rotation.

As shown in Fig. 3, the displaceable disc 24 can be locked in position by a tooth 27 in one of its incisions 25. The tooth 27 is provided on a nickel-plated brass plate 28, coplanar with the disc 24 which plate 28, as shown in Fig. 4, has a hole 29 provided for its removal for adjustment of the position of the disc 24. The tooth 27 has its flanks shaped so as to lock the displaceable disc 24, eliminating any possibility of relative play. The plate 28 is inserted in a radial slot 30 formed in the small plate 16 which has the four radiused corners (not shown in the Figures) to ensure the necessary frictional engagement of the plate 28. The radial slot 30 is also provided with a suitable notch 31 to give access to the hole 29 in the plate 28 by means of a pointed tool 32, shown in Fig. 5, when it is desired to change the position of the disc 24, as stated below. The illustrated device makes it possible, without removing the switch from the panel 12, to change the position of the end stop of the shaft 1 in its clockwise direction of rotation and hence to modify the number of switch positions of the shaft 1, by car rying out the following operations: rotating the shaft 1 in an anti-clockwise direction until the pin 6 stops against the tooth 23 (Fig. 3); removing the plate 28 in the direction of the arrow A (Fig. 5) by insertion of the end of the pointed tool 32 into the hole 29 and rotation of the tool 32 in the direction of the arrow B forming a lever in the appropriate notch 31 in the slot 30; inserting the other end of the tool 32 into the slot 30, previously occupied by the plate 28; rotating the displaceable disc 24 in an anti-clockwise direction until its tooth 26 is in contact with the displaceable pin 6; rotating the shaft 1 in a clockwise direction so that the pin 6 drives the tooth 26 until the desired position in which the stop is to be fixed is reached and reinserting the plate 28 with its tooth 27 engaging one of the twelve incisions 25, to lock the displaceable disc 24 in this position.

In the case of an adjustment to increase the number of positions of the rotor, it is not necessary to rotate the displaceable disc 24 in an anti-clockwise direction but simply to remove the plate 28 and drive the disc 24 in a clockwise direction, by means of the pin 6 and tooth 26, until the desired position is reached.

WHAT WE CLAIM IS: 1. A rotary electric switch having an adjustable stop, comprising a first member mounted cm axially to the shaft of the rotor of the switch and rotatable relative to said shaft in the circumferential direction and provided with a stop member engageable by a pin of the rotor to provide an end stop for the rotor, and means for enabling adjustment of the position of said stop member relative to the rotor, in order to produce the adjustment of the stop position of the rotor, said first member being lockable in position by means of a second, toothed member co-operating with the first member, said second member being displaceable in a radial direction through a slot formed in the body of the switch.

2. A switch as claimed in Claim 1, in which the first member is preferably formed by an annular disc provided with a series of radial slots, distributed around its circumferential edge, the number of slots corresponding to the possible positions of a detent cam of the rotor, and wherein the stop member is a tooth projecting from the disc.

3. A switch as claimed in Claim 2, in which the second member is formed by a flat plate provided with a tooth insertable in one of the slots in the disc and mounted in a radial slot formed in the body of the switch, the plate being mounted co-planar with the disc and removable from outside the switch.

4. A switch as claimed in Claim 2 or 3, in which the flanks of the tooth and/or of each incision in the disc are so formed as to eliminate relative play.

5. A switch as claimed in Claim 2, in which the radial slot provided in the body of the switch formed of a moulded component of thermo- plastic material and has four radiused corners to ensure the frictional engagement with the plate during the removal and insertion of the plate in the slot.

6. A switch as claimed in Claim 3, in which the plate is provided with a hole in which the point of an extraction tool can be inserted so as to permit the removal thereof.

7. A switch as claimed in Claim 5, in which a notch is formed on the radial slot, in which notch a pointed tool can act as a lever for removing the plate.

8. A rotary electric switch having an adjustable stop, substantially as herein described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. rying out the following operations: rotating the shaft 1 in an anti-clockwise direction until the pin 6 stops against the tooth 23 (Fig. 3); removing the plate 28 in the direction of the arrow A (Fig. 5) by insertion of the end of the pointed tool 32 into the hole 29 and rotation of the tool 32 in the direction of the arrow B forming a lever in the appropriate notch 31 in the slot 30; inserting the other end of the tool 32 into the slot 30, previously occupied by the plate 28; rotating the displaceable disc 24 in an anti-clockwise direction until its tooth 26 is in contact with the displaceable pin 6; rotating the shaft 1 in a clockwise direction so that the pin 6 drives the tooth 26 until the desired position in which the stop is to be fixed is reached and reinserting the plate 28 with its tooth 27 engaging one of the twelve incisions 25, to lock the displaceable disc 24 in this position. In the case of an adjustment to increase the number of positions of the rotor, it is not necessary to rotate the displaceable disc 24 in an anti-clockwise direction but simply to remove the plate 28 and drive the disc 24 in a clockwise direction, by means of the pin 6 and tooth 26, until the desired position is reached. WHAT WE CLAIM IS:

1. A rotary electric switch having an adjustable stop, comprising a first member mounted cm axially to the shaft of the rotor of the switch and rotatable relative to said shaft in the circumferential direction and provided with a stop member engageable by a pin of the rotor to provide an end stop for the rotor, and means for enabling adjustment of the position of said stop member relative to the rotor, in order to produce the adjustment of the stop position of the rotor, said first member being lockable in position by means of a second, toothed member co-operating with the first member, said second member being displaceable in a radial direction through a slot formed in the body of the switch.