FR2622349A1 - Timer with manual reset - Google Patents

Abstract

Timer of the type comprising a reduction gear driving a cam in rotation, the profile of which acts on a lever which then actuates an electric switch. It is characterised by means allowing manual rezeroing of the device, especially due to the fact that the lever possesses two degrees of freedom.

Description

The present invention relates to timers of the type comprising a geared motor driving, in rotation. a cam whose profile acts, by means of a lever subjected to the action of a return spring, on the state of an electric switch.

In known devices of this kind, the gearmotor consists of a synchronous motor associated with a mechanical reduction box whose output axis supports and drives a cam in continuous rotation. A lever.

pivoting around an axis, alternately oscillates between two extreme positions. under the action of the cam and a return spring. keeping it constantly in contact with said cam. This type of timer is commonly used to control an electrical switch cyclically. It is simple and inexpensive in design, but it cannot be used for non-cyclical applications requiring resetting of the entire device.

The device, object of the invention. aims to overcome this drawback in a simple way. In this one, in fact, the lever can be at any time from the time manually released from the action of the cam and return to its initial position, against a stop, under the action of the return spring.

To do this. the lever pivots around two axes perpendicular to each other. Thanks to these two degrees of freedom, the lever follows, in a plane, the action of the cam. from which it can however be subtracted by pivoting perpendicular to this plane.

This device makes it possible to produce a timer which can be reset manually, while remaining simple and inexpensive.

The operation will be better understood with the accompanying drawing illustrating, by way of example, an embodiment of the device according to the present invention.

As shown, the device comprises, a synchronous motor 1 and its reducer 2. fixed on a plate 3.

Cam 4 is fixed. for example by means of a pin on the outlet axis 20 of the reducer.

This cam comprises a helical profile 40, of radius increasing from the center towards the periphery. A lever 5 is articulated around an axis 21 integral with the plate 3.

This lever. which can be molded in a relatively flexible plastic material, can also oscillate around a second axis perpendicular to the axis 21. and obtained for example by means of a groove 51 creating a preferred point of bending. A return spring 6. fixed between the lever and the plate. exerts on the lever a force F, directed towards the outside of the plane P swept by the lever during its pivoting around the axis 21.

This direction generates two forces on the lever. F1 and F2 tending to bring it back, on the one hand against a vertical stop 70 and on the other hand on a straight stop 71 and parallel to the plane P. Finally, the lever 5 has a stud 50 serving as a feeler on the cam 4 An electrical switch is provided on the plate 3 so that its control button 80 is actuated by the lever when the probe 50 bears on the largest diameter of the profile 40. It is easily seen that, depending on the space existing between the lever 5. pressing on the stop 70, and the control button 80, a more or less long time delay will be obtained before reversing the switch 8. Alternatively, and in order to be able to adjust or modify the time delay, the switch 8 can be fixed on a plate 9. pivotally mounted around the axis 21 and provided with adjustable fixing means on the plate 3.

for example a light, concentric to the axis 21. and a locking screw. During timeouts. the lever slides in abutment on the rectilinear stop 71, the height of which is provided to prevent said lever from rubbing directly on the profile of the cam.

A part 10 which can move in translation in both directions is disposed under the lever 5. It can be guided in a conventional manner in a box. not shown, containing the device and protruding from it to serve as a reset button. To this end, it carries a development 101 in order to be able to reach the lever 5 whatever the angular position thereof during the time delay.

The operation of the entire device is as follows. When the motor 1 is energized, the cam rotates, clockwise in the drawing, and the lever 5 pivots regularly over time, towards the control button 80 of the switch 8, under the action of the nipple 50 pressing on the profile 40.

To carry out a reset of the device, it is sufficient, by means of the part 10, to lift the lever 5, which has the effect of releasing the stud 50 from the profile 40, and thus allowing the lever to come back into abutment on the element 70 thanks to the fact of the return spring 6.

This very simple device will advantageously be used for all applications where the time delay does not have to be strictly the same between two resets.

Claims (3)

RESELL I CAT I ON S 1 - Timer of the type comprising a gearmotor driving, in rotation, a cam whose profile acts. by means of a lever, subjected to the action of a return spring. on the state of an electric switch characterized in that, to be able to be released from the action of the cam. the lever pivots around two axes perpendicular to each other. 2 - Timer according to claim 1 characterized in that the return spring 6, fixed between the lever 5 and the plate 3, exerts on the lever a force F, directed towards the outside of the plane swept by the lever during its pivoting around the axis 21. and tending to bring it back on stops 70, 71. 3 - Timer according to any one of claims 1 and 2 characterized in that the electric switch 8 is fixed on a plate 9. pivotally mounted around the axis 21 and provided with locking means on the plate 3.