Mechanical locking for contactor banks

Abstract: The locking comprises a mechanism that is inserted between two contactor banks, determining that the operation of any one of them prevents the operation of the other. Said mechanism comprises two sliding pieces (1) and (2) connected to both tiltable cams (4) which are led towards an inoperative position by means of a spring (8), the cams (4) being connected to the sliding pieces themselves (1) and (2) by means of a pivot (6) emerging from each one of them, which is located in a transversal throat (7) of the sliding pieces themselves (1) and (2.) When one of these pieces (1) and (2) moves, the respective cam (4) tilts and comes in between in order to block the other one, preventing the respective sliding piece associated to the latter from being able to move, whereby the pulsator of the other contactor bank will not be able to be operated.

Description: The present invention refers to a mechanical locking device for contactor banks, foreseen to prevent that two specific contactors can be activated simultaneously, either because the respective functions are incompatible or because they define an invariable order sequence. In specific installations, as a heating installation for example, it is necessary that two of the elements that come to form part of the operation must be associated, as far as hookup and start are concerned, in such a way that one of them should always start operating after the other, and the latter should not disconnect after the second element. In this sense, the electric resistor and the ventilator of a heating installation can be cited for example. Therein said resistor should not be connected without the corresponding ventilator being activated. In other words, the connecting of the electric resistor when the ventilator is not operating should be prevented, while when the ventilator is operating activation of the electric resistor is optional and besides, in the connecting position of the electric resistor, the ventilator cannot be disconnected. In such a case it is convenient that the switch of the electric resistor is subjected to the active position of the ventilator switch. US-A-3 210 491 discloses a mechanical locking device for contactor banks according to the pre-characterising part of claim 1, which device establishes functional dependency regarding interrelated contactors. The locking device comprises two sliding pieces being movable longitudinally and in a guided manner in a frame, each sliding piece governing a switch. The device further includes two cams, each cam being fixed to the frame tiltably around a fixed point. Each cam is connected to a corresponding sliding piece by means of a pivot emerging sideways from the cam and that fits in a groove in the corresponding sliding piece. The interconnection between the cams and the sliding pieces is such that a longitudinal movement of a sliding piece implies a tilting movement of the corresponding cam. The mechanical locking device for contactor banks as claimed, is foreseen to carry out the above cited functions, in such a way that in the operation of any of the contactors a pair of banks between which the locking of the invention is inserted, should prevent the operating of the other. In this sense, the mechanical locking device establishes the functional dependency concerning the interrelated contactors, and is formed from a pair of sliding pieces functionally connected to both tiltable cams, in such a way that the runs of the cams mutually interfere with each other, so that one of the end positions of a cam will prevent the movement of the other and vice versa. The sliding pieces are mounted on the general frame of the device, guided longitudinally, each one of them governing the switch of a contactor bank, with the particularity that the connection of the cams to the sliding pieces themselves is carried out by means of a pivot that emerges sideways from each one of the former, fitting in a transversal groove of the respective sliding piece, establishing the transformation of the linear movement of each sliding piece into tiltable movement of the corresponding cam. The mechanism is complemented with some springs that permanently pull the cams, in such a way that the cams occupy a normal rest or inoperative position, the device being complemented with some auxiliary and floating electric contacts placed in transference with terminals mounted on the general frame. In order to complete the description that is going to be made hereinafter and for the purpose of providing a better understanding of the features of the invention, a set of diagrams on the basis of whose figures the innovations and advantages of the mechanical locking device for contactor banks, object of the invention will be more easily understood, is attached. Figure 1 shows a plan view of the general mechanism, revealing the two sliding pieces, as well as the two cams, springs connected to the cams and the general frame where the entire mechanism is mounted. Figure 2 and 3 show both schematic longitudinal representations of the two longitudinally moveable guided sliding pieces on the general frame of the device. Figure 4 shows a plan schematic representation of the contour of the frame, as well as the assembly of the sliding pieces, cams and tilting points of the cams. In view of the figures commented on, one can see how the mechanical locking for contactor banks, object of the invention, is made from two sliding pieces (1) and (2), which are longitudinally guided on a general frame (3), with the particularity that such sliding pieces (1) and (2) which are elongated and are located axially opposite, are connected to both tiltable cams (4), the tilting point of each one of the cams being the shaft (5), which is fixed to the frame (3.) The cams (4), in their tilting, offer both runs that mutually interfere with each other, in such a way that in the end position of one of them movement of the other one will be prevented and vice versa. The connection between each sliding piece and its corresponding cam is done by means of a pivot (6) that emerges sideways from the cam, pivot which is housed in a transversal groove (7) provided for this purpose in the sliding piece itself (1) or (2), all of this in such a way that the cited coupling establishes the transformation of the linear movement of the sliding piece (1) or (2) into tiltable movement of the respective cam (4.) On the other hand, it has been foreseen that each one of these cams (4) is led towards an inoperative position by means of a tension spring (8), as is clearly shown in figures 1 and 4. On their part, the sliding pieces (1) and (2) are connected to the switch of the corresponding contactor bank, including in an operative way the auxiliary and floating electric contacts (9), which are placed in transference with the terminals (10) mounted on the frame itself (3.) In this way, when one of the sliding pieces (1) or (2) is activated by means of the pulsator of the corresponding contactor bank, the axial or forward movement thereof will determine the tilting of the respective cam (4), in such a way that in said position the body itself of said cam (4) is located in such a way that it interferes with one part of the other cam preventing the latter from tilting, and thus preventing the other sliding piece from being able to move forward. In short, it is determined that the pulsator of the other contactor bank cannot be operated, until the mechanism returns to its initial inoperative position, just as is shwon in figure 1.

Claims: A mechanical locking device for contactor banks, said device establishing functional dependency regarding interrelated contactors, said device consisitng of: a frame (3); a first sliding piece (1) and a second sliding piece (2), said sliding pieces (1,2) being movable longitudinally and in a guided manner in said frame (3), each sliding piece (1,2) governing a switch of a corresponding contactor bank, each sliding piece (1,2) having a first surface, said first sliding piece (1) and said second sliding piece (2) being disposed facing each other, such that the first surface of said first sliding piece (1) is facing the first surface of said second sliding piece (2); two cams (4), each cam (4) being fixed to the frame (3) tiltably around a fixed point (5) corresponding to said cam (4); one of said cams (4) being connected to the first sliding piece (1) by means of a pivot (6) emerging sideways from said cam (4) and that fits in a transversal groove (7) in the first surface of said first sliding piece (1), and the other one of said cams (4) being connected to the second sliding piece (2) by means of a pivot (6) emerging sideways from said cam (4) and that fits in a transversal groove (7) in the first surface of said second sliding piece (2), such that a longitudinal movement of one sliding piece (1,2) causes a tilting movement of the corresponding cam (4) around the corresponding fixed point (5); the bodies of said cams (4) having runs that interfere with each other, such that in a determined position, one of the end portions of a cam prevents the movement of the other cam and vice versa; characterized in that the two cams (4) are disposed tiltably in the same plane; the shapes of said two cams (4) in said plane are such that in a determined position, one portion of one of said cams (4) in said plane prevents the movement of the other cam (4), and vice versa; the two cams (4) are situated at least partially between the first surface of the first sliding piece (1) and the first surface of the second sliding piece (2), said pivots (6) fitting in the corresponding transversal grooves (7) such that each sliding piece (1,2) transfers its movement to the corresponding cam (4) when said sliding piece (1,2) moves in a first longitudinal direction as well as when it moves in a second longitudinal direction, opposite to said first longitudinal direction. A mechanical locking device according to claim 1, wherein the cams (4) are led by corresponding springs (8) towards an inoperative position. A mechanical locking device according to any of the preceding claims, wherein the sliding pieces (1,2) include auxiliary floating electric contacts (9), placed in transference with terminals (10) mounted on the frame (3).

Inventors: AGUT SANZ JUAN, AGUT SANZ, JUAN
Applicants: AGUT SA, AGUT, S.A.
Application year: 1993
Main classification: H01H50
IPC codes: H01H50