Actuating device for a circuit breaker with element for disabling switching

Abstract

 Actuating device (100) for a circuit breaker comprising a driving element (109) movable between an opening position (109') and a closing position (109''), a disabling element (124) movable between a rest position (124') in which it allows movement of the driving element (109) and a working position (124'') in which it prevents movement of the driving element (109), a hole (129) for receiving a padlock for locking the disabling element (124), the disabling element (124) in the working position (124'') allowing access to said hole (129) and in the rest position (124') preventing access to said hole (129)

Description

[0001] The present invention relates to an actuating device for a circuit breaker.

[0002] Actuating devices (or actuators) are commonly used, for example in control systems for industrial plants, to perform switching operations (opening and closing) of the circuit breaker using energy other than manual energy. Typically, actuating devices use an electric motor to move a driving element connected to an operating lever of the circuit breaker from an opening position into a closing position, and vice versa, in response to a suitable external command signal.

[0003] Usually, the actuating device includes a disabling element movable between a rest position, in which it allows movement of the driving element, and a working position, in which it prevents movement of the driving element. This disabling element is used to prevent improper use of the circuit breaker; for example, in the case where the circuit breaker has been opened owing to a malfunction of a circuit in which the circuit breaker is arranged, it prevents a spurious command signal from causing closing of the circuit breaker or prevents said circuit breaker from being inadvertently closed manually.

[0004] The actuating device is also provided with a hole for locking the disabling element, for example by means of a padlock. The disabling elements of the known actuating devices are provided with an additional hole which, when the disabling element is in the working position, is facing the abovementioned hole so as to allow locking of the disabling element in this position.

[0005] A drawback of the known actuating devices consists in the fact that when the disabling element is in the rest position it is possible to access the hole formed on the actuating device; therefore, the disabling element may be inadvertently locked in the rest position. This makes it impossible to displace the disabling element into the working position; for example, in the event of a malfunction of the circuit in which the circuit breaker is arranged, it is not possible to prevent closing of the circuit breaker, with a high risk of damage to the circuit breaker and the connected devices.

[0006] The object of the present invention is to overcome the abovementioned drawbacks. In order to achieve this object, an actuating device for a circuit breaker as described above is provided, in which the disabling element in the rest position obstructs access to the hole formed on the actuating device.

[0007] The actuating device of the present invention allows the disabling element to be locked only when it is in the working position. This actuating device therefore ensures greater safety of the entire system within which it is connected.

[0008] Further characteristic features and advantages of the actuating device according to the present invention will emerge from the description, given below, of a preferred embodiment thereof, provided by way of a non-limiting example, with reference to the accompanying figures, in which:

Figs. 1a and 1b show a perspective view of the actuating device according to the present invention in various operating conditions.

[0009] With reference in particular to Fig. 1a, an actuating device 100 for a circuit breaker (not shown in the figure) is illustrated, being used typically as a servomotor in a closed-chain control system; the actuating device 100 is suitable, however, for use also in different applications, for example for simple remote operation of the circuit breaker.

[0010] The actuating device 100 comprises an insulating body 103, on one lateral flank of which a terminal strip 106 for connecting the actuating device 100 to an electrical supply network is provided. The terminal strip 106 is also used for applying to the actuating device 100 suitable (opening and closing) command signals which are supplied by a remote control device (not shown in the figures).

[0011] The actuating device 100 is provided with a bar 109 (or other equivalent driving element) arranged in a step 110 formed on a front wall of the insulating body 103. The driving element 109 is pivotably mounted on the insulating body 103 so as to be able to rotate about an axis 115 substantially perpendicular to this front wall. A bottom surface of the driving element 109 is provided with a longitudinal channel 121 for engagement with an operating member of the circuit breaker (not shown in the figure). When the actuating device 100 receives a closing or opening command signal, the driving element 109 is rotated by a suitable electric motor (not shown in the figure); in particular, the driving element 109 moves from an opening position 109' shown in continuous lines into a closing position 109'' shown in broken lines, or vice versa, its movement also causing displacement of the circuit breaker operating member so as to close or open said circuit breaker.

[0012] The actuating device 100 includes an element 124 for disabling the movement of the driving element 109 consisting of a body 125 (for example made of plastic) in the form of a parallelepiped movable (as described in detail below) in an operating direction 126 perpendicular to the axis of rotation 115. The body 125 is mounted on the step 110 formed on the front wall of the insulating body 103 and has a size substantially the same as that of said step 110.

[0013] An additional step 127 is formed, perpendicularly with respect to the step 110, on a left-hand side wall of the insulating body 103. The step 110 and the step 127 are separated from one another by a flange 128 in which a hole 129 is formed (perpendicularly with respect to the operating direction 126), said hole receiving, as described in detail below, a padlock (or other equivalent locking means). A channel 130 is also provided on a left-hand side wall of the body 125 for facilitating access to this hole 129.

[0014] Advantageously, the body 125 has a width with respect to the operating direction 126 which is substantially equal to the dimensions of a finger, so that the disabling element 124 can be handled more easily; preferably, this width is greater than 1 cm, for example between 1 cm and 2 cm. In a preferred embodiment, an upper surface of the body 125 is furthermore provided with a knurled zone 131 having grooves perpendicular to the operating direction 126, so as to improve gripping of the disabling element 124.

[0015] A front surface of the body 125 has, formed in it, a substantially ovoid-shaped recess 132 which partially houses the driving element 109; the recess 132 has a width greater than the distance covered by the driving element along its trajectory between the closing position 109' and the opening position 109''.

[0016] A tongue 133 extends perpendicularly from a side wall of the recess 132 at its left-hand end. The tongue 133 has a height which is less than the difference between the width of the recess 132 and the distance covered by the trajectory of the driving element 109. A matching cavity 136 is formed on a left-hand side wall of the driving element 109.

[0017] An internal wall of the recess 132 is provided with a guide 139 for the driving element 109, consisting of a relief in the form of an arc of a circle with its centre on the axis of rotation 115. The relief 139 extends from a bottom edge of the recess 132 in the vicinity of its right-hand end as far as the driving element 109 in the opening position 109'. The rear surface of the driving element 109 is provided with a matching groove 142, in the form of an arc of a circle, which slides on the projection 139 during rotation of the driving element 109 between the opening position 109' and the closing position 109''.

[0018] A rear wall of the body 125 is also provided with a cavity 145 which houses a microswitch 148 which projects from a facing wall of the insulating body 103; the microswitch 148 includes a plunger button pushed outside the insulating body 103 by a suitable spring (not shown in the figure).

[0019] When the disabling element 124 is located in the rest position 124' shown in the figure, the tongue 133 does not interfere with the cavity 136, so that the driving element 109 is free to rotate about the axis 115 between the opening position 109' and the closing position 109'', with the driving element 109 which partly follows the configuration of the side wall of the recess 132. In this situation, in the actuating device 100 according to the present invention, the hole 129 is obstructed by the body 125 so as to prevent locking of the disabling element 124 in this position. It should be noted moreover that advantageously the disabling element 124 is aligned with the insulating body 103 so as to indicate visually to an operator a correct operating state. The switch 148 is housed in the cavity 145 so as to be kept in an open condition which allows energization of the motor operating the driving element 109.

[0020] When, with the driving element 109 in the opening position 109', the disabling element 124 is displaced towards the right into a working position 124'', as illustrated in Fig. 1b (the elements already shown in Fig. 1a are indicated by the same reference numbers), the tongue 133 engages into the cavity 136. In this condition, the driving element 109 is locked in the opening position 109', so that the circuit breaker cannot be closed. The present invention may, however, also be realized with different systems for preventing movement of the driving element. It should be noted that, advantageously, the disabling element 124 in the working position projects from the insulating body 103 so as to indicate visually to an operator the malfunction situation.

[0021] When the disabling element 124 is in the working position 124'', the body 125 frees access to the hole 129; a padlock (not shown in the figure) can therefore be inserted into the hole 129 so as to lock the disabling element 124 in this position. It should be noted that the channel 130 formed on this body 125 allows advantageously access to the hole 129 with a reduced travel of the disabling element 124.

[0022] In the working position 124'', the cavity 145 also disengages from the microswitch 148 which is therefore closed by the rear wall of the disabling element 124, so as to interrupt energization of the motor which operates the driving element 109. This advantageously prevents any spurious command signal from activating the motor, which could be damaged by operating the driving element 109 locked by the disabling element 124.

[0023] With reference to Fig. 1a again, let us now consider a situation in which the driving element 109 is located in the closing position 109''. In this condition, engagement between the projection 139 and the groove 142 prevents translation of the disabling element 124 in the operating direction 126. Therefore, the disabling element 124 cannot be displaced into the working position (124'' in Fig. 1b), preventing accidental locking of the driving element 109 in the closing position 109''. The present invention may, however, also be realized with other equivalent mechanisms for locking the disabling element.

[0024] The disabling element described above is particularly compact, reliable and effective. Moreover, it is extremely simple and can be mass-produced (for example by means of a moulding process) at a low cost, so that it does not increase the final cost of the entire actuating device.

[0025] Obviously, the actuating device described above may be subject to numerous modifications and variations carried out by a person skilled in the art, in order to satisfy contingent and specific requirements, all of which however are contained within the scope of protection of the invention, as defined by the claims below.

Claims

1. Actuating device (100) for a circuit breaker comprising a driving element (109) movable between an opening position (109') and a closing position (109''), a disabling element (124) movable between a rest position (124') in which it allows movement of the driving element (109) and a working position (124'') in which it prevents movement of the driving element (109), a hole (129) for receiving a padlock for locking the disabling element (124), the disabling element (124) in the working position (124'') allowing access to said hole (129),
   characterized in that

the disabling element (124) in the rest position (124') obstructs the access to said hole (129).

2. Actuating device (100) according to Claim 1, in which the disabling element (124) includes a channel (130) formed on a surface arranged in the vicinity of said hole (129) so as to allow access to said hole (129) with a limited movement of the disabling element (124).

3. Actuating device (100) according to Claim 1 or 2, further comprising a mechanism (139,142) for locking the disabling element (124) in the rest position (124') when the driving element (109) is in the closing position (109'').

4. Actuating device (100) according to Claim 3, in which said mechanism (139,142) includes a guide (139) arranged on the disabling element (124) and a matching groove (142) formed on the driving element (109) so as to move rotatably the driving element (109) about an axis of rotation (115), in the rest position (124') the guide (139) being disengaged from the groove (142) when the driving element (109) is in the opening position (109') so as to allow movement of the disabling element (124) and the guide (139) being engaged with the groove (142) when the driving element (109) is in the closing position (109'') for preventing movement of the disabling element (124).

5. Actuating device (100) according to Claim 4, in which the guide (139) consists of a curved projection in the form of an arc of a circle with its centre on the axis of rotation (115).

6. Actuating device (100) according to any one of the Claims 1 to 5, further comprising a tongue (133) arranged on the disabling element (124) and a matching cavity (136) formed on the driving element (109), in the rest position (124') the tongue (133) being disengaged from the cavity (136) so as to allow movement of the driving element (109) and in the working position (124'') the tongue (133) being engaged with the cavity (136) so as to prevent movement of the driving element (109).

7. Actuating device (100) according to any one of Claims 1 to 6, in which the disabling element (124) has a width with respect to the operating direction (126) greater than 1 cm.

8. Actuating device (100) according to any one of Claims 1 to 7, in which the disabling element (124) has a knurled zone (131) on an operating surface.

9. Actuating device (100) according to Claim 8, in which said knurled zone (131) consists of grooves perpendicular to the operating direction (126).

10. Actuating device (100) according to any one of Claims 1 to 9, in which the disabling element (124) in the rest position (124') is aligned with an insulating body (103) of the actuating device (100) and in the working position (124'') projects from said insulating body (103).

11. Actuating device (100) according to any one of Claims 1 to 10, further comprising a microswitch (148) and a further matching cavity (145) formed on a further surface of the disabling element (124) facing the microswitch (148), in the rest position (124') the microswitch (148) being housed in the further cavity (145) so as to be kept in an inactive condition in which it allows energization of a motor operating the driving element (109) and in the working condition (124'') the microswitch (148) not being housed in the further cavity (145) so as to be kept by the further surface in an active condition in which it interrupts energization of said motor.

12. Disabling element (109) for use in the actuating device according to any one of Claims 1 to 11.

Drawing