Device for Locking the Control Member of an Electrical Appliance of the Manual Control Type

1. Field of the Invention

The present invention relates to a device for locking the control member of an electrical appliance of the manual control type.

2. Description of the Prior Art

It is known that, in the case of certain types of electrical appliances which are designed for manual control, especially switches placed in the power supply system of a distribution network, it may be desirable to maintain the control member in a predetermined position, in particular for safety reasons.

Devices for locking the manual control member of an electrical appliance are already known. However, these devices do not usually permit easy and effective positioning of a padlock or of a lead seal. Some types of locking device can in fact be fitted with a padlock but their structure is such that effective locking cannot be obtained simply by means of a lead seal. Other types of locking device can on the contrary be provided with an effective seal but are not designed for the purpose of fitting padlocks.

One aim of the present invention is to provide a device for locking the control member of an electrical appliance of the manual control type which has a simple structure and permits effective locking both by means of a padlock and by means of a simple lead-sealed wire.

In order to achieve this objective, there is provided in accordance with the invention a device for locking the control member of an electrical appliance of the manual control type, said device being essentially constituted by two adjacent portions pivotally joined together by means of a hinge portion, fastening means each extending along an edge portion located in spaced relation to said hinge portion, at least one bearing surface provided on one of the adjacent portions aforesaid and at least one locking orifice formed in each adjacent portion and so arranged as to come into position in register with the corresponding locking orifice of the other adjacent portion when the device is in the locking position.

Thus, while the device is being placed in position, the two adjacent portions are inclined with respect to each other about the hinge portion and the bearing surface is located at a distance from the manual control member which can be operated if so required. On the contrary, when the locking device has been placed in position with the locking orifices in register, the bearing surface prevents operation of the manual control member. The locking device can be maintained in the locking position either by the shackle of a padlock which extends through the orifices or by a wire passed through the orifices and tightly secured against the edge of the locking device by means of a lead seal.

In an advantageous embodiment of the invention, the hinge portion between the adjacent portions projects with respect to the bearing surfaces when the device is in the locking position. Thus the locking device is applied against the manual control member with greater force.

In a preferred embodiment of the locking device in accordance with the invention, the locking orifices are formed in wings, each wing being hinged with one of the adjacent portions.

Thus the locking device can be manufactured in the flat state and the locking orifices are placed in oppositely-facing relation by rotating the wings about their respective articulation means or hinge elements.

In accordance with another distinctive feature of the preferred embodiment of the invention, at least one of the wings has a positioning stud which extends transversely to the plane of the wing and the other wing has a corresponding hole for receiving the positioning stud when the device is in the locking position. Thus, by causing the positioning stud of one wing to penetrate into the corresponding hole of the other wing, positioning of the locking device is ensured prior to positioning of the retaining means such as the padlock or the lead-sealed wire.

According to another aspect of the invention, the locking orifices are closed-off by means of a partition wall which is brittle in a direction transverse to its plane and resistant in a direction substantially parallel to its plane, said partition wall being preferably provided with weakening grooves. It is thus possible to cut-out the partition wall so as to form an orifice which corresponds exactly to the cross-section of the retaining means.

Other features of the invention will be more apparent upon consideration of the following description and accompanying drawings, wherein:

FIG. 1 is a top view in perspective showing the locking device in the open position;

FIG. 2 is a bottom view in perspective showing the locking device in the open position;

FIG. 3 is a perspective view of the device in the closed position;

FIG. 4 is a diagrammatic sectional view of a manual-control appliance at the moment of positioning of the locking device;

FIG. 5 is a diagrammatic sectional view of a manual-control appliance with the locking device in the closed position;

FIG. 6 is a diagrammatic sectional view of an alternative embodiment of the locking device in position on an electrical appliance provided with a push-button control.

As shown in the figures, the locking device in accordance with the invention comprises two bearing portions or base portions 1 pivotally joined together by means of a hinge portion 2. Fastening means formed in this example by lugs 3 which form projections with respect to the ends of the bearing portions 1 each extend along an edge portion located in spaced relation to the hinge portion 2. In the embodiment shown in the drawings, each bearing portion 1 has a bearing surface 4 and is associated with orifice means comprised of three locking orifices 5 which are intended to come into position opposite to and in register with the corresponding locking orifices of the other bearing portion when the device is in a locking position (as shown in FIGS. 5 and 6).

The hinge portion 2 formed by a thin wall in the form of a bridge between the bearing portions 1 projects with respect to the bearing surfaces 4 (as shown in FIGS. 5 and 6).

The locking orifices 5 are formed in wings 6, each wing being pivotally joined to one of the adjacent bearing portions 1 by means of a hinge element 7.

In the embodiment illustrated in the drawings, each wing 6 is provided with a positioning stud 8 which extends transversely to the plane of the wing 6 and with a hole 9 which corresponds to the positioning stud 8 in the other wing for receiving said positioning stud when the device is in the locking position. The studs 8 and holes 9 are thus complementary means for mutual positioning of the wings.

FIG. 5 illustrates an alternative embodiment of the device in which the orifice means 5 are closed-off by means of a thin partition wall 10 in which are formed weakening grooves 11, with the result that the thin partition wall 10 is brittle in a direction transverse to its plane and is relatively resistant in a direction substantially parallel to its plane.

By way of example, the locking device in accordance with the invention has been made of plastic material and more particularly polypropylene which has a sufficient degree of strength and rigidity to ensure that the bearing portions 1 in the form of plates and the wings 6 are rigid while having at the same time a sufficient degree of flexibility to ensure that a thin wall made of this material has the requisite flexibility to form the hinge portions 2 and 7. It has thus been possible to mold the device in one piece. Said device can therefore be produced rapidly at low cost.

FIGS. 4 and 5 illustrate the positioning of the locking device in accordance with the invention on a switch provided with a casing 12 having recesses 13, the shape of which is substantially complementary to that of the lugs 3 of the device. The lugs 3 and recesses 13 are engagement means for mutaul engagement of each base portion with the housing. The switch is provided in addition with a pivoted manual control lever 14, a recess 13 being located on each side of said lever.

For the purpose of positioning the device, the two bearing portions 1 are inclined with respect to each other about the hinge portion 2. The wings 6 are located in any position and may, for example, be folded back substantially at right angles to the bearing portions 1 as shown in FIG. 4. The lugs 3 are then introduced into the recesses 13, whereupon the bearing portions 1 are thrust back by hand while maintaining the wings 6 in substantially parallel relation until the moment when the locking orifices 5 of each wing 6 are in register. The control lever 14 of the switch is thus located opposite to a bearing surface 4 and, in the case shown in FIG. 5, on one side of the hinge portion 2 which projects with respect to the surface 4. The wings 6 are then applied against each other and the stud 8 of one wing penetrates into the corresponding hole 9 of the other wing, with the result that the device is temporarily maintained in the locking position. The device is then maintained more securely in the locked position either by introducing one or a number of locking members being padlock shackles 15 having a diameter in the vicinity of the orifice 5 which has been formed in the wing 6 or by means of a locking member being a wire 16 which is tightly secured within one orifice 5 by means of a lead seal 17. It is observed in practice that, by reason of the small clearance which exists between the orifice 5 and the padlock shackle 15 or between the loop of the wire 16 and the rims of the wings 6, the bearing portions 1 are capable of pivotal displacement about the hinge portion 2 only to a negligible extent and any attempt to operate the control lever 14 has the effect of bringing this latter into contact with the bearing surface 4 and the side of the hinge portion 2 without any possibility of pivotal displacement of the control lever 14 over its full range of travel. Furthermore, by locking the hinge portion 2 between the adjacent portions 1, the locking means prevent the device from being forcibly removed since the lugs 3 cannot be disengaged from the recesses 13.

In the alternative embodiment of FIG. 6, the locking device in accordance with the invention is more particularly adapted to a switch comprising two pushbuttons 18, 19 which are depressed or withdrawn in alternate sequence. As in the preceding embodiment, the device comprises two bearing portions 1 which are pivotally displaceable about a hinge 2 and are adapted to support wings 6 in which are formed orifices 5. In this embodiment, one of the bearing surfaces 4 projects with respect to the plane of the other bearing surface 4 and, at the time of positioning of the device, is placed opposite to the pushbutton 19 which is in the depressed position. Thus, aside from the fact that the upper bearing portion 1 masks the push-button 18, this push-button cannot be operated since it would cause outward displacement of the push-button 19 which would then come into abutting contact with the corresponding bearing surface 4.

As will readily be apparent, the invention is not limited to the embodiments described in the foregoing and alternative forms of construction may accordingly be contemplated.

By way of example, the bearing portion 1 is not necessarily made of plastic but can be formed of rigid material such as steel or a light alloy, in which case the hinge 2 is formed by a pin engaged within sleeves rigidly fixed to the bearing portions 1. The openings 5 can also be formed in wings 6 which are rigidly connected to the portions 1 in a transverse direction with respect to these latter.

Although the device in accordance with the invention has been shown with three orifices 5 which permit the introduction of three different padlocks in accordance with prevailing safety standards, provision can be made for only one orifice associated with each bearing portion 1 or on the contrary for a greater number of orifices.

It is readily apparent that the profile of the bearing surfaces 4 can be adapted to the shape of the manual control member of the electrical appliance on which the locking device is mounted.

Moreover, although the hinge portion 2 is shown in the drawings in a central position of the device for reasons of symmetry of movement of the manual control lever 14, it would be possible to place the hinge portion 2 in an off-center position or to replace this latter by any equivalent means permitting displacement of the bearing surfaces 4 in order to move them away from the manual control lever when the orifices 5 are not maintained in register and on the contrary to maintain these latter in proximity to the manual control lever when the orifices 5 are placed in register and maintained in this position.