US3406266A

US3406266A - Timed switch-control device

Info

Publication number: US3406266A
Application number: US620478A
Authority: US
Inventors: Herve Raymond
Original assignee: La Telemecanique Electrique SA
Current assignee: Telemecanique SA
Priority date: 1966-03-11
Filing date: 1967-03-03
Publication date: 1968-10-15
Anticipated expiration: 1985-10-15
Also published as: GB1126640A; FR1483795A; SE345927B; ES337850A1; BE694920A

Description

Filed March 3,

R. HERVE TIMED SWITCH-CONTROL DEVICE 2 Sheets-Sheet 1 Oct. 15, 1968 R. HERVE TIMED SWITCH-CONTROL DEVICE 2 Sheets'- Sheet 2 Filed March 5, 1967 LOCE-S States Patent 3,406,266 TIMED SWITCH-CONTROL DEVICE Raymond Herve, La Celle-Saint-Cloud, France, assignor to La Telemecanique Electrique, Nanterre, Hauts-de- Seine, France, a French body corporate Filed Mar. 3, 1967, Ser. No. 620,478 Claims priority, applicatitirzzl 'rance, Mar. 11, 1966,

. 8 Claims. (Cl. 200-34 ABSTRACT OF THE DISCLOSURE Contact devices are known in which timing of the return motion of an element which operates the contacts of the device may be effected pneumatically through the agency of a slow change in volume of a timer chamber one wall of which is a diaphragm associated with a central valve, the chamber communicating with an external space through a controllable air throttle.

The air throttle may consist of a needle valve or a passage containing compacted fibrous material.

It has also been proposed that the air throttle might be constituted bya valve having two flat discs resiliently urged into contact with one another, and one of which discs possesses on that of its faces opposite the other a fine groove which is closed off by the other disc. The other disc has apertures which communicate with the passage thus formed, so that, in accordance with the relative position of the discs, a greater or lesser length of the groove is utilised. Thus, the flow of air from the cxteriorto the chamber and vice versa, is throttled and this alters the changes in the volume of the said chamber.

In known embodiments of a timer device which employs a disc valve arrangement, the different component elements are coaxially superimposedupon one another, but this complicates production.

In the case of the simplest of these devices, the contactoperating element is directly connected to the diaphragm and the timer chamber communicates on the one hand through the valve and on the'other through the capillary passage (or other air throttling device), directly with the atmosphere.

This embodiment has certain drawbacks:

The precision and reliability of operation are dependent upon the air which flows through the capillary passage being completely free of dust. This result can be achieved by providing a filter. However, in the known embodiment, since a fresh quantity of atmospheric air is fed to the device ateach operation, the risk of the filter becoming choked is high.

Devices are also known in which the diaphragm separ-ates two virtually closed chambers, air flowing from one to the other in one direction through a central valve of the diaphragm and in the other through a capillary passage. A device of this form which, in efliect, uses air in closed circuit is advantageous from the point of view of functional reliability.

Finally, a timed switch control device is known, in which the air throttle is situated laterally in relation to the diaphragm and communicates with the chambers through passages which are radially disposed in relation to the diaphragm.

The present invention relates to a timed switch control device, with a timer chamber in simple design and great reliability.

In accordance with the invention, the body of the I timer device is a moulded component which has a cavity closed off by a diaphragm and constituting the timer chamher, and two further cavities, the second of which at least partially envelopes the first, the first of the two further cavities being closed off by a filter and the second by a sealed wall, the timer chamber and the first of the further cavities communicating with one another through the medium of an air throttle and passages formed in the moulded component, whilst the second of the further cavities communicates through narrow passages, likewise formed in the moulded component, with the space located at the external side of the diaphragm.

Preferably, this latter space is a compartment containing the contacts themselves, which compartment communicates with the atmosphere through a narrow passage.

In addition, the air throttle will, advantageously, be a disc valve arrangement, the seating for which is created in one face of the moulded component, normal to the diaphragm, the passages linking this valve with the timer chamber and with the first cavity, being disposed radially in relation to the centre of the diaphragm, in the moulded component.

In an embodiment of the construction just mentioned, the contact compartment constitutes, together with the two further cavities in the switch casing, a second chamber associated with the timer chamber, in which the air passing from one to the other circulates in a virtually closed circuit.

Preferably, the contact operating element is a slidable push-button associated with a frame which serves as a contact bridge in conjunction with springs whose central position, corresponding to the maximum deflection of the spring, is unstable so that even when the movement of the push-button is slow, the movement of the contact bridge is rapid.

Preferably, this externally-operated push-button will be enclosed and guided between a base and a cover which, when assembled together, form between them the contact chamber, the base supporting the body of the timer device and the fixed contacts, and the cover trapped between the assembly of base and body, preferably being transparent in order to enable the contacts to be inspected.

The base will preferably be in the form of a bracket so that it can be attached to a side face of an electromagnetic relay provided with a contact operating strip which is movable perpendicularly in relation to the side face (i.e. parallel to the mounting panel of the relay) in order to be able to operate the push-button during one or other of its reciprocating movements.

A relay of this kind, with a moving strip, has been described, in particular, in United States patent specification No. 3,277,410 filed Aug. 31, 1964 and its Canadian equivalent No. 910,585 filed Aug. 28, 1964.

The ensuing description is of an example of the invention and relates to the accompanying drawings of which:

FIGURE 1 is a side elevation of a timed contact device embodying the invention,

FIGURE 2 is an end elevation,

FIGURE 3 is an axial section through the device,

FIGURE 4 is a perspective view of the push-button,

FIGURE 5 is an end elevation of the device, partially cut away, from the end opposite to that of FIGURE 2,

FIGURE 6 is a view in the direction indicated by VIVI in FIGURE 1, and

FIGURE 7 is a perspective view of the cover of the compartment containing electric contacts, the cover being s'hown'tipside down. i a V axially, this push-button having, as FIGURE 1 shows, a

part E which projects externally. In order to enable the contacts to be inspected, the cover is, advantageously, made of a transparent material.

' The base A and the body B are assembled together by means of three bolts 60 the heads and shanks of which are contained in passages 61 (FIGURE produced during moulding of the timer body B.

The cover D has a shoulder 62 which, when the cover has been assembled on the base A, is underneath the top face of the timer body B so that the cover cannot be released and is attached in sealed fashion at its edges, to the base A.

A device embodying the invention is designed to be associated with any kind of mechanism capable of applying a pressure to the tip E in order to trigger the switch timer system. In particular, the device may be attached to one of the ends of an electromagnetic relay F such as described for example in the specifications mentioned above. A relay of this kind has a contact-carrying strip G, schematically illustrated in FIGURE 1, which is capable of reciprocation parallel to the mounting panel to which the relay is attached (this is indicated by the doubleheaded arrow H), and this strip cooperated with the tip E of the push-button.

The device is held in place against the relay F by the dowel portions 2a on the face 2 of the base A, these dowel portions engaging grooves in the side faces of the relay F, and by the bolts 1 associated with the mating flanges of relay F and base A. Since the apparatus illustrated in the figures can be attached at either end of the relay F, the strip G can cooperate with the push-button A either in the rest state or in the working state, so that the set-up can be arranged to provide timed contact operation either on opening or on closing of the relay contacts.

As FIGURE 4 indicates, the push-button E has a cruciform transverse cross-section. It is guided in a T-section groove 3 in the base A, the T-section being completed by a portion 4 (see also FIGURE 7) of the cover D, to from a complete cross. This portion 4 comprises two pillars 4a against which abut the faces 5 of the push-button E, whilst shoulders 6 of the push-button are guided between the pillars 7 which are also integral with the cover D.

In the sides of the push-button two mutually opposite recesses 8 are formed into which there extend the ends of springs 9 of S-shape, which are responsible for the movement of a frame 10 provided on each of its faces with contacts 11 which move between pairs of fixed contacts 12 integral with screw terminals 13 by which the apparatus is externally connected into circuit. The terminals 13 are fixed to the base A between the moulded flanges 36 thereof.

A contact device constituted by a push-button passing through a frame acting as a contact bridge, the connection between frame and push-button being effected through S-shaped springs, is known per se. It is known that the springs 9 are unstable at their point of maximum deflection. Thus, when the push-button E is displaced in one direction or the other, the frame remains in contact with a pair of fixed contacts until the springs reach their maximum deflection but as soon as the position of the push-button corresponding to maximum deflection is passed the frame 10 moves rapidly in the opposite direction to the push-button, thus passing from one pair of fixed contacts to the other.

The internal end E of the push-button, also of cruciform cross-section, is enlarged and rests" a'gainsf'aflat thrust plate 14 integral with a rod 15 of a valve 16. Through the medium of a spring 17, the thrust plate 14, in turn, acts on a stiffened central portion 18a of a diaphragm 18, whose periphery 18b is sealed to the edge of a cavity in the timer body B. g

The valve 16 and the diaphragm 1 8 are biased into rest positions by a spring '19 whilst the spring 17 acts in the opposite sense to urge the diaphragm 18'and a seating thereon against the valve when the pushbutton 'E is not operated. The spring 19 is carried on a screw 20 which can be used toadjust the degree of compression, the screw engaging, through a sealing arrangement, the centre of a hollow conical boss 21 on the timer bodyB. This boss,attached to a, wall 22 of the body, forms in conjunction with the diaphragm 18 the timer chamber 23. In thethickness of the wall 22 are two passages 24 and 25 (see'also FIGURE 6) which open out at 24a and 25a respectively into the top face ofthe body B and at 2417 and 25b respectively, on either side of the wall 22 (see also FIGURE 5).

The central boss 21 is surrounded by a circularwall 26, moulded in situ within the body B, which wall defines in the body, at the side opposite to the diaphragm, two cavities, the first of which is central and is surrounded by the other. The wall 26 contains along its free edge, a groove in which there is located an air filter 28 associated with a seal 27. The central cavity closed off by the filter, thus forms a compartment 29.

The external cavity of the body B is closed off at the back, in sealed fashion, by a plate 30 which is held in place by rivets 31 (FIGURE 5) projecting from the moulded flanges and, like the passages 61, the external cavity is formed in situ within the body B. At its centre, plate 30 has a boss 32 of the resilient material which holds the filter 28 in position. The external cavity thus formed by.the plate 30 forms a compartment 33 which communicates with the compartment containing the contacts through two small passages 34.

The latter compartment is completed by the assembly of the cover D on the base A, the cover, as FIGURE 7 shows, having hollow elements 35 which enclose two central flanges 36 (FIGURE 1) separating the contact terminals 13.

The top face of the body B contains arecess 37 inwhich there are situated a rubber seal 38 and a disc 39, both being prevented from turning by the pips 40 on the edge of the recess. The seal 38 and the disc 39 contain

apertures

41 and 42 corresponding in position with those open ends 24a and 25a of the passages 24, 25. The aperture 42 extends on the top face of the disc 39 into a radial groove 43 which leads to a circular undercut 44 in the disc. On this same face, the aperture 41 extends towards the exterior, in the form of an elongated groove 45.

On top of the disc 39, there is applied through the medium of a second sealing arrangement 46, a second disc 47 which on that of its faces in contact with the disc 39, has a radial groove 48the external end of which extends into a fine circular groove 49 which intersects the elongated recess 45.

The

discs

39 and 47 are of a plastic material and are accurately moulded and polished so that they can be placed in intimate contact with one another to provide '{an airtight seal.

The assembly constituted by the disc valve arrangement is enclosed in the recess formed in the underside of a knob 52 and compressed by the dished spring washer 50 with which there co-operates the screw 51, this screw passing through the button and engaging in the body B. A top recess in the knob, in which there is lodged the head of the screw 51, is closed by a cover 53 press-fitted into place, this cover carrying markings which indicate the delay time.

The device which has just been described, operates in the following manner:

In the rest state (the position illustrated in FIGURE 3), the tip E of the push-button projects externally of the device and the contact bridge constituted by the frame closes a circuit passing through those contacts 12 and terminals 13 which are nearest the body B (FIGURE 6). The valve 16 is closed by the force of the spring 17 on the diaphragm and the thrust plate 14 is forced into contact with the push-button E by the spring 19.

When the tip E of the push-button is depressed, forcing the push-button inwards, the intermediate thrust plate 14 moves the disc of the valve 16 whilst the spring 17, which is compressed, in turn moves the diaphragm towards the right in FIGURE 3. The air contained in the timer chamber 23, which is initially compressed in accordance with the load of the spring 17, is forced through the valve towards the contact compartment. In the course of this movement, when the springs 9 pass through their point of maximum deflection, the contact bridge is suddenly displaced towards the contacts 12 and the terminals 13 which are furthest from the body B.

As soon as the push-button is released, the valve 16 closes (this as soon as the chamber 23 has emptied) so that the diaphragm 18 tends, under the action of the spring 19, to return to its original position and therefore the air pressure in space 23 drops. As a consequence, air is drawn through passage 25, the circular groove 44 acing as collector, the radial groove 48, a certain length of the groove 49, the recess 45 and the passage 24, in order to restore to normal the air pressure in the chamber 23. This movement of air is the slower the longer the length of groove 49 included in the above path. The air which enters the passage 25, is drawn from the contact compartment, through the small passages 34, the compartment 33, the filter 28 and then the compartment 29. In effect, therefore, it is virtually the same air which was expelled from the timer chamber which ultimately returns to it and the device thus virtually operates in closed circuit fashion.

Equilibrium with the atmospheric pressure in the assembly, is achieved by the narrow passages created by the external projection of the tip E of the pushbutton. However, preliminary precipitation of dust which may enter the apparatus and of dust which may arise from contact wear, is effected in the contact compartment and air which passes through the narrow passages 34 has consequently had the bulk of any dust removed. Subsequently this air passes through the filter 28 and this arrangement therefore means that the chances of the groove 49 being blocked are negligible.

During its return movement, the diaphragm picks up the thrust plate 14 which in turn returns the push-button E to its original position.

When the device is associated with a relay, as illustrated in FIGURE 1, the push-button E is normally depressed and a single pair of the terminals 13 is used all in accordance with whether it is desired to have timed opening or timed closing of the contacts.

The time delay depends upon the viscosity of the air and, consequently, upon ambient temperature so that the most that can be done is to graduate the apparatus in markings (indicated on the plate 53 opposite an index carried by the cover D) such as a succession of letters of the alphabet, which suggest a change in the delayed time without in any way attempting to indicate the actual delay time. To this graduation, however, a zero indication can be added, corresponding to the setting of the button 52 to a position in which the radial groove 48 is directly in communication with the annular collector 42 and the recess 45. In this circumstance, the delay is negliible.

g The embodiment which has been described above is amenable to modification, in particular by the substitution of equivalent technical means, without departing from the scope of the present invention.

What I claim is:

1. An improved switch-control device having a timer chamber which is closed by a diaphragm associated with a contact operating element and which communicates with an external space through an air throttle situated laterally in relation to the diaphragm wherein the improvement comprises a moulded body component having a timer chamber closed 011 by the diaphragm, two further cavities of which the second at least partially envelopes the first, the first closed ofi by a filter and the second by a sealed wall, the timer chamber and the said first cavity communicating with one another via an air throttle and passages in the moulded component, whilst the second cavity communicates through a passage also created in the moulded component with a space located outside the timer chamber.

2. A device as claimed in claim 1 wherein the space located outside of the time chamber is a compartment in which electric contacts are located, this space being in communication with atmosphere.

3. A device as claimed in claim 1 wherein the air throttle comprises in combination a disc valve arrangement, the seating for which is formed in a face of the moulded component which is perpendicular to the diaphragm, the said passages being disposed in said moulded component radially with respect to the centre of the said diaphragm.

4. A device as claimed in claim 2 and further comprising an operating element in the form of a sliding pushbutton, a frame associated with the push-button and which acts as a contact bridge in conjunction with springs havin an unstable central position, the push-button having a tip which projects outside the contact compartment.

5. A device as claimed in claim 2 wherein the compartment containing the contacts comprises in combination a base to which there are attached the body and the fixed contacts, and a cover, the assembly of body and base trapping the cover in place.

6. A device as claimed in claim 5 wherein the base of the contact compartment is in the form of a bracket to permit its attachment to a lateral face of an electromagnetic relay equipped with a contact-operating strip, the strip being movable in a direction perpendicular to the lateral face.

7. A device as claimed in claim 4 wherein the pushbutton is of a cruciform transverse cross-section.

8. A device as claimed in claim 5 wherein the cover constitutes in association with the base, a passage for the push-button, which passage has surfaces for the guidance of the push-button.

References Cited UNITED STATES PATENTS 3,153,706 10/1964 Faffart 335-61 3,213,237 10/1965 Mikina et a1 335--61 3,213,333 10/1965 Mikina et al 335-61 ROBERT K. SCHAEFER, Primary Examiner. H. O. JONES, Assistant Examiner.