GB Patent 886306 - Improvements in or relating to time switches

Claims

-WHAT I CLAIM IS:- L.An electric clock having means for carrying out time switching of an operational ChIcuit ;Wndl comprising a periodwally a0ting self-winding action operated by means of an electromagnet connected to a low voltage direct-current source, preferably a battery, a spring contact, connected to one terminal of the direct-current source, revolving with a shaft of an hour hand of the clock and adapted to co-operate with two contact members, which are arranged on metal rings insulated electrically from the clockwork and adapted to be rotated relative to one another separately by means of a setting member said spring contact being connected by way of sliding contacts abutting against the setting rings with exciter coils of two magnetic switches influencing a switch member for the operational circuit switch, the first magnetic switch being adapted to move the switch member against a return mechanism into the "O'ST" position and the second magnetic switch being adapted to disengage from its operative position a resilient pawl ret i i g the switch member in its "ON" position, so that the switch member is released to return into its switch-off position and that the current return is effected by the exciter coils of the magnetic switches to a second terminal of the direct-current source, in the case of the switch-on magnet by way of the pawl and also a sprmig retaining die latter in its disengaged position, thus only contacting the switch member when it is in the "OFF" position, and in the case of the second magnet effected by means of a spring being in live connection only in the "ON" posi- don. 2. A clock as claimed in Claim 1, in which the switch member for the operational circuit switch in its two operational positions forms a live bridge between the second terminal of the direct-current source and the

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springs belonging to the two magnetic switches. I A clock as claimed in Claim 1 or 2, in which an engaging roller, disposed between the two rings is connected with a displaceable knob for selectively coupling the -roller with one of the two setting rings. 4. A clock as claimed in Claim 1, 2 or 3, in which one of the two rings arranged behind the face is fixed on an insulating disc mounted rotatably on a boss of a hand shaft and the second ring is rotatably mounted on this disc of insulating material and contact members bearing setting marks extend- ing in front of the face of the two rings pass through a central aperture of the face, whilst the spring contact co-operating with the contact members of the rings is mounted on the rear surface of a disc mounted between the hands and the face on the hour hand shaft which disc covers the central aperture of the face. 5. An electric clock constructed and arranged to operate substantially as herein described with reference to and as illustrated in the nrr-nmn:invii.o riruv.-;n#q_

Description

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Improvements in or relating to Time Switches, L HEINRicH RITTER, Of 1, Lenaustaffel, Esslingen/Necker, Germany, a German national, do hereby declare the invention, for which I pray that a patent may be granted to me, and -the method by which it is to be performed, to be particularly described in and by the following statement:- The invention concerns an electric clock with a periodically acting self winding device operated by means of an electromagnet connected to a source of direct current of low voltage, preferably a battery, such -a clock having a time switch for actuating, for example, the circuit of an electric heating element.

Time switches are known, namely in the form of clocks with a spring winding device and two alarm mechanisms, which are tripped by means of locking pins controlled by means of the clockwork movement by mechanical means which cause the closing and opening of switch contacts of the operating circuit. With electric clocks of the aforementioned kind, tbt conneation elf dit dockwark Wiibh such a time switch mechanism fails due to the fact that power required to actuate the trip pins cannot be produced by the weak winding spring provided for a running period of only about one minute.

According to the present invention an electric clock, having a periodically acting self-winding action by means of an electromagnet connected to a low voltage direct- c=.en# siowce, preferably ia battery, and having means for carrying out time switching of an operational circuit, comprises a spring contact which is connected to one terminal of the direct-current source and revolves with a shaft of an hour hand of the clock and which is adapted to co-operate with two contact members, which are arranged on metal rings insulated electrically from the clockwork and are adapted to be rotated relative to one another separately by means of a setting member said spring contact being connected by* way of sliding contacts abutting against the setting rings with exciter coils of two magnetic switches influencing a switch member for the operational circuit switch, the first magnetic switch being adapted to move the switch member against a return mechanism into the "ON" position and the second magnetic switch being adapted to disengage from its operative position a resilient pawl retaining the switch member in its "ON" position, so that the switch member is released to return into its switch-off position and that the current return is effected by the exciter coils of the magnetic switches to a second terminal of the direct-current source, in the case of the switch-on magnet by way of the pawl and also a spring retaining the latter in its disengaged position, thus only contacting 'the switch member when it is in the "OF" position, and in the case of the second magnet effected by means of a spring being in live connection only in. the "ON" position.

Thus the additional stressing of the wind- up spring of the clockwork is limited to frictional resistance of sliding contacts, which due to the small capacity of the magnetic switches chosen for the operational switch is very small. A further advantage resides in the fact that the whole switching circuit is connected to the low dangerless voltage of a conventional battery used for operating pocket torches, which battery is preferably used at the same time for winding the clock and that the magnetic switches on being excited switch themselves off again immediately, thus only a short impulse is necessary for each switching as well as for the cocking of the wind-spring of the clockwork. The additional loading of the battery by means of the time switch mechanism is therefore hardly noticeable; it merely consists in the fact that, to the switching effected approxi-

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mately every minute for cocking the wind- spring, occasional switchings for the magnetic switches possessing approximately the same capacity as the time switch mechanism are added.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is an axial section through a time setting device of a clock and also a diagrammatic view of a time switch device in the "OF" position and an electric wiring diagram; Fig. 2 is a partial front elevation of the clock; and Fig. 3 is a time switch device in the "ON" position.

A time setting device comprises a clock 1, a hollow shaft 2 of an hour hand 3, a minute hand shaft 4, a minute hand 5, a boss 6 on the hour hand shaft 2 and a clock face 7. A disc 8 consisting of insulating material is mounted on the boss 6 of the hour hand shaft behind the face 7, so as to be freely rotatable thereon. A peripherally extending metal ring 9 is fixed to the rear face of the insulating disc 8. A second identical metal ring 10 is rotatably mounted on the front of the disc 8. A friction roller 11, mounted on an axially displaceable adjusting shaft 12 which carries a rotary knob 14 in front of a front plate 13, engages between the two metal rings 9 and 10. By displacing the knob 14 in the direction of the arrow 15 it is possible for the friction roller 11 to be caused to make contact alternatively with one or the other of the metal rings 9 and 10, so that by turning the knob this metal ring is engaged and rotated. Thus it is possible for each of the two metal rings 9 and 10 to be set at any angular position. Alternatively, in place of the friction roller 11 the rings 9 and 10 may be in the form of toothed crown wheels engageable by an adjusting roller toothed on either side.

A contact member 16 is mounted on the front surface of the insulating disc 8 and is electrically connected with the setting ring 9 mounted on the rear of the insulating disc 8. A second contact member 17 mounted on the same side of the insulating disc 8 and rotatable therewith is connected with the ring 10. Each of the two contact members 16 and 17 passes forwardly through a central aperture 18 of the face 7 and is connected with a setting mark 19 and 20 respectively, these setting marks being disposed over the front of the clock face 7 and projecting beyond the outer periphery of a metal disc 21 mounted on the shaft 2 of the hour hand. The disc 21 covers the aperture 18 of the face 7, so that the positions of both rings 9 and 10 are visible from the outside. A spring contact 22, mounted on the rear sur- face of the cover disc 21 and connected with the hour hand shaft 2, is caused successively to make sliding contact with the contact members 16 and 17 of the two setting rings 9 and 10 which lie in the movement range thereof.

The shaft 2 of the hour hand, by way of parts of the clockwork electrically connected therewith, is connected by means of a lead 23 to a terminal 25 of a battery 24, the other terminal of the battery being designated 26. The spring contact 22 is constantly connected to the battery terminal 25, so that one of the setting rings 9 or 10 and its corresponding contact member 16 or 17 respectively is live, when in contact with the spring contact 22. Sliding contacts 27 and 28 abut respectively against the setting rings 9 and 10 and leads 29 and 30 are respectively connected therewith, the leads 29 and 30 respectively being connected to exciter coils 33 and 34 respectively of two electromagnets 31 and 32. The current return from the exciter coils 33 and 34 to the second terminal 26 of the bateiry 24 is effeut2d by meatas of leads 35 and 36 as described hereunder.

The electromagnets 31 and 32 have attracting Raps 37 and 38, which, when their respective exciter coils 33 and 34 are switched in, influence a switch member 39 of an operating current switch 40 in the form of a tun*ler swi`t#-h -such as a nilcro-switch which has a considerable switching capacity and small dimensions. The switch member 39 in the form of a lever is linked at 41 to a housing of the operating current switch 40 and, by way of a ram 42 acts on a switch spring 43 of the tumbler switch. Fig. 1 shows ithe "OFF" Ploishion. Th,# swiitich aever 39 is swung into its "ON" position against a return mechanism disposed in the tumbler switch 40.

The attracting flap 37 of the magnet 31 acts on the switch lever 39 to switch it into the operative position. The magnet 31 is thus the "switch-on" magnet. An insulating member 44 acting as stop for the flap 37 is mounted on the switch lever 39. In its "ON" position the switch lever 39 is adapted to be l6cked by means of a pawl 46, subjected to the action of a spring 45, mounted on an insulating panel 47, a notch 48 in the pawl 46 engages over the switch lever 39 as soon as it has been swung by the flap 37 of the "switch-on" magnet 31 into the "ON" position (Fig. 3). The current return lead 35 of the magnet 31 is connected to a spring contact 49 fixed on an insulating member 50; the contact 49 abuts against the pawl 46 as long as the latter has been disengaged from its locking position with the sw1kch, Ilover 39 in the "OFF" position. If when the switch lever 39 has been moved into the "ON" position the pawl 4165 is engaged then it is swung away from the spring con-

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tact 49. The pawl 46 in turn is connected with the second terminal 26 of the battery 24, whereby the switch lever 39 is used as a live bridge. An isolator switch 52 is arranged in a connecting lead 51 between the battery terminal 26 and the switch lever 39. A second spring contact 53, arranged on an insulating member 54 and connected with the current return lead 36 of the magnet 32, makes live contact with the switch lever 39, when the latter has been brought into its "ON" position by means of the flap 37 of the "switch-on" magnet 31. When the switch lever 39 is moved into the "OFF' position this live connection is broken. The attracting flap 38 of the "switch-off" magnet 32 is capable of moving the pawl 46 into its disengaging position when a stop 55 thereof is pressed, so that the switch lever 39 can automatically swing back into its "OFF" position.

The time switch works as follows:- By pushing in the knob 14 the setting ring 9 is first set in such a way that its setting mark 19 shows the time for switching on the operational circuit on the clock face 7. Then, by retracting the knob 14, the setting ring 10 is turned until its setting mark 20 shows the time for switching off the operational circuit on the face 7. Hence setting has been effected.

As soon as the spring contact 22 revolving with the hour hand 3 touches the contact member 1-6 of the setting ring 9, the circuit 25, 23, 2, 21, 22, 16, 9, 27, 29, 33, 35, 49, 46, 39, 51, 52, 26 is closed, whereby the "switch-on#' magnet 31 is excited and the attracting flap 37 thereof swings the switch lever 39 int(; its "ON" position. When the "ON" position is reached the notch 48 of the pawl 46 engages over the switch lever 39 and retains the latter in the "ON" position. At the same time the pawl 46 is lifted off the spring contact 49, so that the above-men- tioned circuit is broken and by this magnet 31 switched off. Thus the magnet 31 when reaching the "ON" time receives a brief current impulse, although the spring contact 22 still remains a considerable time in live connection with the "switch-on" contact 16. Simultaneously with this switching-on the switch lever 39 has received shunt connection with the spring contact 53, which however at first remains ineffective.

When the set switch-off time has been reached then the spring contact member 22 which in the meantime has passed beneath the contact member 16 touches the contact member 17 of the setting ring 10 and the circuit 25, 23, 2, 21, 22, 17, 10, 28, 30, 34, 36, 53, 39, 51, 52, 26 is closed. The "switch- off" magnet 32 is now switched-on and the attracdng flap 38, by striking against the stop 55, disengages the pawl 46 from its 1ocking position vielndve to the switch lever 39, so that the latter is free and can be returned into the "OFF" position by means of the return mechanism. When the switch lever 39 moves into the "OFF" position the contact between it and the spring contact 53 is broken; this results in the circuit of the "switch-off" magnet 32 being interrupted and a further existence of the contact connection between the spring contact 22 and the contact member 17 remains ineffective. Thus even the "switch-off" magnet 32 receives only a brief impulse.

The battery 24 may also be used for feeding the wind-up magnet of the clock (not shown). It would, however, also be possible for a separate battery to be provided for this purpose. The two electromagnets 31 and 32 serving to switch the operational circuit on and off may be constructed with the same electric characteristics as the wind- uD map-net of the clockwork.