GB2023934A - Electromechanical time-lag relay of narrow construction - Google Patents

Abstract

An electromechanical time-lag relay has at least one set of contacts actuable without a time-lag, at least one set of contacts actuable with a time-lag, a synchronous motor driving reduction gearing coupled to a time-lapse wheel, and a coil having an armature. The synchronous motor 14 and the coil 1 are attached to a common heat conducting plate, the axis of rotation of the synchronous motor 14 extending perpendicular to a longitudinal axis of the time- lag relay and the axis of the coil 1 extending parallel to said longitudinal axis. The contact sets 5, 6, 7, and 15, 16, 17, each comprise members inserted in and retained by a part consisting of insulating material which is partly overlapped by a front plate. The free ends of the contact set members directly support the contacts and a respective lever 3, 9 is provided for actuating each contact set. The lever 9 is driven by a spring 8 from the lever 3 and after the set time-lag operates contact sets 15, 16, 17. <IMAGE>

Description

SPECIFICATION Electromechanical time-lag relay of narrow construction The invention relates to an electromechanical timelag relay having at least one set of contacts actuable without a time-lag and at least one set of contacts actuable with a time lag, a synchronous motor driving reduction gearing coupled to a time-lapse wheel, and a coil having an armature.

For many years, electromechanical time-lag relays of this type have been an established component in time-dependent switching operations in control engineering. The actual timing device is formed by the constant running of a synchronous motor in contrast to electronic time-lag relays, which utilise the charging or discharging of a capacitor andlor suitable logic circuits.

In recent years with the advent of miniaturization, relays operating purely electronically have had to be used instead of electromechanical relays because they occupy a smaller space even though electromechanical relays may be preferred for operational reasons.

The arrangement of the synchronous motor with stepdown gearing, and of the coil with a magnetic armature and sets of contacts, is substantially more bulky than the equivalent electronic circuit mounted on a printed circuit board. Both electronic and electromechanical time-lag relays can be made with a depth and height necessary for standardisation with other equipment available on the market.

However, the width of electromechanical time-lag relays can be a problem when no-delay contacts and the possibility of switching functions with a time-iag are required. Electromechanical time-lag relays having a relatively narrow construction are available on the market but they do not offer both possibilities of no-delay contacts and contacts actuated with a time-lag which can only be found with electronic construction.

An object of the present invention is to construct an electromechanical time-lag relay of the aforementioned type such that it has an extremely narrow construction with dimensions which could only be achieved previously with electronic time-lag relays.

According to the present invention there is provided an electromechanical time-lag relay having at least one set of contacts actuable without a time-lag, at least one set of contacts actuable with a time-lag, a synchronous motor driving reduction gearing coupled to a time-lapse wheel, and a coil having an armature, characterised in that the synchronous motor and the coil are attached to a common heat conducting plate, the axis of rotation of the synchronous motor extening perpendicular to a longitudinal axis of the time-lag relay and the axis of the coil extending parallel to said longitudinal axis of the time-lag relay, the contacts sets comprise members inserted in and retained by a part consisting of insulating material which is partly overlapped by a front plate, the free ends of the members directly supporting the contacts, and a respective lever is provided for actuating each contact set.

The present invention provides an electromechanical time-lag relay which departs from the conventional arrangement of the synchronous motor with its axis of rotation along the longitudinal axis of the relay. An arrangement is provided in which the axis of rotation is located at right-angles to the longitudinal axis of the relay and also at right-angles to the axis of the coil. The overall width of the relay is ultimately limited to the width of the coil and its armature and the height of the synchronous motor.

All the other parts, such as stepdown gearing, sets of contacts, switching levers, time-lapse wheel and the like can be arranged spatially with respect to each other to achieve a particularly flat construction. Such a flat construction could cause problems with regard to the dissipation of heat. This problem is overcome however by distributing the heat over the relatively large surface area of the heat conducting plate which is preferably of metal. The synchronous motor as well as the coil with the magnetic flap are both attached to the plate. Wiring between the individual electrical components is advantageously reduced to a minimum due to the fact that the sets of contacts and their terminal connections are constructed in a special manner and have a favourable spatial arrangement with respect to each other.The contact set actuating levers are preferably shaped such that they can perform auxiliary functions such as indicating the switching position of the sets of contacts. The adjustment of the time-lapse wheel is advantageously reconciled with the extremely narrow construction of the electromechanical time-lag relay due to the fact that the time-lapse wheel is constructed in the form of a drum. The drum rotates about an axis at right-angles to the longitudinal axis of the time-lag relay and is located with its peripheral surface at least partly visible through a window on the front side of the time-lag relay. The drum is in rotary connection with a knurled wheel, which can be operated from the front side of the time-lag relay so the exact adjustment and pre-selection of the time can take place without error and in a troublefree manner.The rotary movement of the drum indicates that the time-lag relay is operating and its stoppage indicates that the time-lapse has ended. Finally, it is particularly advantageous that the metal plate taking over the function of distributing heat can be connected by a simple plug-in connection to a further plate supporting the other components of the timelay relay.

An embodiment of the invention will be described hereafter by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective side view of a time-lag relay according to the invention with its casing removed, a front plate being shown spaced from the time-lag relay; Figure 2 is another perspective view of the timelag relay according to Figure 1 taken from the opposite side; Figure 3 shows side views of a lever for actuating a set or sets of contacts which operate without delay and of a lever for actuating a set of contacts operating with a time-lag; Figure 4 is a partial view of an upper plate of the time-lag illustrating the coupling function; Figure 5 shows side elevations of the time-lag relay according to Figures 1 and 2; and Figure 6 is a partial cross section through the upper part of the time-lag relay in the region of the front cover.

The illustrated electromechanical time-lag relay comprises individual components attached to a plate which is composed of two parts. The lower part 40 of the plate in the drawings supports a synchronous motor 14 and a coil 1 having an armature 2. The lower part of the plate is made of metal and as a result of its relatively large surface area, dissipates and distributes the heat produced by the components it supports. The lower metal plate 40 can be inserted without the assistance of further securing members in an upper plate of synthetic material shown in the drawing. The upper and lower plates are frictionally engaged together and locked due to the fact that passing through overlapping regions of the plates are journal bearings which support gears of stepdown gearing.The stepdown gearing provides an output the speed of rotation of which is less than that of the synchronous motor 14. As shown particularly in Figure 2 and the left-hand part of Figure 5, one end face of the synchronous motor 14 rests against the metal plate 40, i.e. its axis of rotation is located at right-angles to the longitudinal axis of the electromechanical time-lag relay. The axis of the coil is located parallel to the longitudinal axis of the relay, the coil 1 also being attached to the metal plate 40. The output pinion of the synchronous motor which is not shown in detail, transmits its rotary movement by way of the stepdown gearing consisting of a plurality of gears and a coupling mechanism to a time-lapse wheel 12. The time lapse wheel is constructed in the form of a drum and is located in the upper part immediately below a front plate 26 which forms a casing cover.The time lapse wheel 12 is located with part of its peripheral surface, which is provided with a time scale, facing a slot-like opening or "window" in the casing cover.

It is possible to adjust the desired time-lag, (i.e. the time after which a set of contacts is to be actuated) by means of a knurled wheel 19 which extends through a further slot-like opening in the casing cover or front plate 26. This slot is located parallel to the window (c.f. in particular Figure 6).

Located directly below the casing cover 26 and left free by the latter are connecting terminals 28 for the time-lag relay. The galvanic connection of the terminals 28 to the individual sets of contacts will be described in detail hereafter. A lever 3 serves for controlling contacts which operate withut delay by way of the armature 2, whereas a lever 9 controls a contact which operates after a time-lag. The levers 3 and 9 are shown in detail in Figure 3.

If a voltage is applied to the coil 1 of the electromagnetic time-lag relay, then the armature 2 is attracted against the action of the force of a coil spring 24 and tilts the lever 3, which is pivotally mounted on the pivot pin A, from the inoperative position illustrated on the left-hand side in Figure 5.

The lever 3 is tilted so that as is apparent from Figure 3, a spacer stud 4 which is located in a recess within the lever 3 is raised. As a result of this a central contact attached to the free end of a U-shaped resilient tongue member 5 is brought out of frictional connection with a contact supported on a member 6 into a corresponding conducting connection with a contact supported on a member 7. This occurs without delay. As shown in Figure 2, the contact members 6 and 7 and the central contact member 5 connected to the terminal 28 are inserted in the upper plate which is injection-moulded. The contact members are suitably connected to connection terminals as shown.

At the same time as the actuation of the set of contacts which operate without a time-lag, the lever 9 for actuating the set of time-lag contacts is biased by means of spring 8 acting between the lever 9 and a journal 3.1 fixedly attached to the lever 3. The spring 8 is placed under tension in the way shown in the drawing. At the time of the operating movement of the armature 2, the journal 3.2 shown particularly in Figure 4, which is an integral component of the lever 3, releases an abutment member 10 and thus the gear 11 located thereon, so that the gear 11 can engage in teeth provided on the time-lapse wheel 12.

The set of time-lag contact is operated by means of the lever 9. The shape of the lever 9 is illustrated at the top in Figure 3, the lever 9 having a nose-shaped projection bearing on a cam 12.1 (c.f. also Figure 4).

Once released, the abutment member 10 is rotated by a spring 13 about the support point B. After the gear 11 engages the time-lapse wheel 12, the synchronous motor 14 rotates the time-lapse wheel 12 by way of the stepdown gearing, until the nose-shaped projection on the lever 9 drops into the recess in the peripheral surface of the cam 12.1. The lever 9 which is biased by means of the spring 8 is then tilted and actuates the set oftime-lag contacts.

The rotation of the time-lapse wheel 12 together with the cam 12.1 takes place in the clockwise direction.

In a manner similar two the connection between the connecting terminals for the contacts which operate without delay, the connecting terminals for the contacts which operate with a time-lag by way of the lever 9 are connected to the terminals in a manner which does not require wires, as can be seen clearly from the detailed illustration in Figure 3. Central contact member 15 is thus moved by means of the journal 9.1 on the lever 9 from contact member 16 to contact member 17. At the same time as this actuation of the time-lag contacts occurs, the journal 9.3 pushes the bearing part 10 out of its inoperative position such that the gear 11 is disengaged.

Both of the levers 3 and 9 have extensions in the form of legs which in Figure 3 comprises projections extending upwards to points above the axes of rotation of the levers. The projections, as can be seen in conjunction with Figures 1 and 2, extend into the region of the casing cover 26 and their positions can be monitored through lateral notches in the slot-like openings in the cover 26. Thus at any time it is easy to see from outside whether the various contact sets have or have not been actuated. Observation of the projections is made easier by colouring them. The coloured surface for the contact set which operates without delay is designated in Figure 2 by the reference numeral 3.3, and for the contact set with operates with a time-lag is designated in Figure 1 by the reference numeral 9.2.

When a voltage is applied to the coil 1 and the synchronous motor 14, the various contacts sets are operated as described above. Thereafter components of the electromechanical time-lag relay return to their initial positions. This is due to the fact that when the coil 1 is not energised, the spring 24 pulls the armature 2 back into its initial position. As a result the lever 3 is returned to the initial position shown in Figure by turning about the pivot point A and the armature 2 falls against yoke 25. Thus the lever 9 is released in the manner shown in the drawings.

As afore-mentioned, the adjustment of the timelag relay for pre-selecting thetime is made by rotating adjusting wheel 18 (c.f. Figure 6) using the knurled wheel 19.

The adjustment of the time-lapse wheel 12 is effected by the stop 18.1 which is moved as a result of the manual actuation of the knurled wheel 19. The wheels 18 and 19 are interengaged by internal toothing. In conjunction with a coil spring 20, a further stop 12.2 brings about the return of the time-lapse wheel to the initial position against the stop 18.1. The required friction, which is necessary in order that the adjusting wheel 18 is not adjusted by the return operation of the time-lapse wheel 12, is provided by a spring 21 and a ball 22 shown in Figure 6. The ball 22 is pressed against the knurled wheel 19 by the spring 21. The wheel 19 is prevented from falling out by a small plate 23. Thus, when the knurled wheel 19 is actuated manually, it is necessary to overcome the frictional force which is present due to the afore-described mechanism.

In the arrangement illustrated in Figure 6 it should be stressed that for adjustment, the time-lapse wheel 12 is rotated in the same direction as that of the knurled wheel 19. An additional measure for preventing rotation of the adjusting wheel 18 is provided by wedging the knurled wheel 19 with a casing journal 27.1. As regards further details, reference should be made expressly to the drawings.

As shown in Figures 1,2 and in particular Figure 3, the connecting terminals, which are located on both sides in the upper region of the mechanical time-lag relay below the casing cover in a stepped arrangement, consist of electrically-conducting shaped members. These members support the contacts directly at their free ends in such a way that internal wiring can be dispensed with. These shaped members 6,7,28, 16, 17 and 29 are inserted in slot-like recesses in the upper injection-moulded part of the time-lag relay, so that a particularly simple assembly results. Their free ends, i.e. the ends located opposite the screw connecting terminals, are additionally prevented from rotating in the said injectionmoulded part. Thus, tightening of the terminal screws cannot produce any relative displacement between the said contacts.

Claims (9)

1. An electromechanical time-lag relay having at least one set of contacts actuable without a time-lag, at least one set of contacts actuable with a time-lag, a synchronous motor driving reduction gearing coupled to a time-lapse wheel, and a coil having an armature, characterised in that the synchronous motor and the coil are attached to a common heat conducting plate, the axis of rotation of the synchronous motor extending perpendicularto a longitudinal axis of the time-lag relay and the axis of the coil extending parallel to said longitudinal axis of the time-lag relay, the contact sets comprise members inserted in and retained by a part consisting of insulating material which is partly overlapped by a front plate, the free ends of the members directly supporting the contacts, and a respective lever is provided for actuating each contact set.

2. An electromechanical time-lag relay according to Claim 1, characterised in that the plate supporting the coil and the synchronous motor is a metal plate which can be inserted in and retained by a further plate consisting of insulating material.

3. An electromechanical time-lag relay according to Claim 1 or 2, characterised in that the said levers are provided with extensions for indicating the switching condition of the respective contact sets, the extensions appearing inside a window in the front plate at the time of contact set actuation.

4. An electromechanical time-lag relay according to Claim 2, characterised in that the contact members which are retained by being inserted in a part of the time-lag relay consisting of an insulating material, are secured against rotation attheirfree ends by engagement with recesses in the plate consisting of insulating material of the time-lag relay.

5. An electromechanical time-lag relay according to any preceding claim, characterised in that the time-lapse wheel is constructed in the form of a drum and is provided with a time scale along its peripheral surface which is at least partly visible inside a recess in the front plate, the time-lapse wheel being connected to rotate with a knurled wheel actuable from the front plate.

6. An electromechanical time-lag relay according to any preceding claim, characterised in that the lever for actuating said set of contacts actuable with a time-lag is biased by means of a leg spring acted on by a projection fixed to the lever for actuating said set of contacts actuable without a time-lag.

7. An electromechanical time-lag relay according to any preceding claim, characterised in that the lever for actuating said set of contacts actuable without a time delay is movable from an inoperative position to a switching position against the action of a spring by the coil armature.

8. An electromechanical time-lag relay according to Claim 1, characterised in that the contact members are locked in position by the front plate.

9. An electromechanical time-lag relay substantially as hereinbefore described with reference to the accompanying drawings.