US3233052A

US3233052A - Interlocking mechanism

Info

Publication number: US3233052A
Application number: US287436A
Authority: US
Inventors: Maurice G Contal
Original assignee: Telemecanique Electrique SA
Current assignee: Telemecanique SA
Priority date: 1962-08-17
Filing date: 1963-06-12
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01
Also published as: FR1338932A; NL125905C; NL291927A; DE1214305B; AT245086B; ES287600A1; BE633097A; GB1037275A; DK113454B; CH395249A

Description

Feb. 1, 1966 M. G. CONTAL 3,233,052

INTERLOCKING MECHANISM Filed June 12, 1965 L 5 -1 J i Lf ijtf -L i 3,233,052 INTERLOCKING MECHANISM Maurice G. Contal, Paris, France, assignor to La Telemecanique Electrique, Nanterre, Seine, France, a company of France Filed June 12, 1963, Ser. No. 287,436 Claims priority, application France, Aug. 17, 1962, 907,138 8 Claims. (Cl. ZOO-50) This invention relates to interlocking mechanism of the type serving to prevent the simultaneous displacement of two displaceable elements. It has been especially developed in connection with electrical relay and contactor apparatus, as a safety device for preventing simul taneous actuation of a pair of contactor units eg both to contact-making condition.

Safety interlocking devices of this class are widely used in electrical engineering, one common instance of theirusefulness being provided by the situation where a reversible twoor more-phase AC. motor is connected to the power supply by way of two contactor units, the separate actuation of each of which will cause the motor to rotate in a corresponding direction by reversal of the connection between the phase windings of the motor and the supply. Should both contactors be actuated simultaneously through inadvertence or accident, a short-circuit betweenmotor phases would result and serious damage would occur.

To avoid those and similar occurences, both electrical and mechanical interlocking devices have been developed, the provision of a mechanical interlock being frequently desirable because of its more positive action. One common form of mechanical interlock device comprises a pair of lever arms rockable about parallel axes and mounted to be actuated by the respective contactors on movement of the latter to actuated condition. In the initial or inactive condition of both contactor units the two arms may be directed towards each other at an angle of about 90. Actuation of one of the contactor units will rock the related arm towards the other arm, and into engagement or near-engagement with it, whereupon it is placed in the path of rotation of said other arm thereby preventing actuation of the other contactor unit solong as the first unit remains in its actuated condition.

It is an object of this invention to provide an improved form of interlocking mechanism of this general charactor, but having various advantages over the conventional forms such advantages including part or all of the following: reduced overall space requirements, an especially valuable feature in connection with miniature electrical equipment; simplicity of the parts and ease of manufacture as well as positive and efiicient operation; similarity of both rocking components of the mechanism in the case of symmetrically arranged contactor units, whereby both components can be manufactured simultaneously and simply mounted in mutually inverted relation; no development of undesirable stresses in the mechanismwhen one unit is actuated and in the event of an inadvertent attempt to actuate the other, and especially no stresses that might tend to'restore the actuated unit to its idle condition; the provision of a simple traction spring interconnecting both component members for biassing both members to their idle positions and simultaneously acting to hold associated parts in related positions. Other objects and advantages will appear.

The invention in its chief aspect comprises interlocking arms projecting from the respective members in mutually crossed relation, means actuated by each element on displacement thereof to its displaced position to rock a related one of said members from a first to a second angular position in a direction tending to move the related United States Patent O arm away from its crossed relation with the other arm, and a part on each arm projecting towards the other arm in a direction generally parallel to said axes and so positioned that with both members in their first positions said parts are. clear of each other so that either member can be displaced to its second position, while with one member in its second position the projecting part thereof stands in the path of the projecting part of the other member whereby the latter cannot be displaced to its second position.

An exemplary embodiment of the invention will now be described for purposes of illustration but not of limitation with reference to the accompanying drawings wherein:

FIGURE '1 is a plan view, from below, showing the improved interlock applied to a pair of associated contactor units each having a pair of displaceable actuator elements in the form of vertically slidable rods:

FIGURE 2 is a sectional elevation of the mechanism on line 11-11 of FIGURE 1; in both FIGURES 1 and 2 the electrical contactor units with which the mechanism of the invention is associated are shown in general outline only; and

FIGURE 3 is a'perspective view of one of the two similar rocking members of the interlock mechanism.

In the drawings the interlocking mechanism of the invention is shown as applied to a pair of contactor units C1 and C2, shown in dot-dash outline. Each contactor unit, conventional per se, is shown by way of example as including an E-shaped magnetic core 1 having an energizing winding coil 2 on its central leg, and an E-shaped movable armature 3, having its three legs registering with those of core 1, and suitably mounted above the core. Secured to the top of the armature 3 is'a cruciform plate 4. To the outer ends of the laterally projecting legs of the plate 4, beyond the sides of the core and armature, are attached vertically depending rods 5,-which are guided for vertical sliding movement in respective casings 6. Both contactor units C1 and C2 are supported on the top of a common base plate 7 having vertically depending side flanges 7a.

On energization of the winding 2 of either of the contactor units, say C2, the armature 3 of that unit is attracted downwardly and causes, through the resilient connection provided by the cruciform plate 4, a corresponding downward displacement of the related pair of rods 5. In this downward displacement, the rods 5 act to close and/or open any number of contact means, not

shown, provided within the casings'6. In the inoperative condition of both contactor units as shown in the drawings, the lower ends of both pairs of actuator rods 5 lie substantially flush with the under surface of the base plate 7, while in the operated condition of a contractor unit, the related actuator rods 5 project below said under surface of the base plate.

The interlocking mechanism that will presently be described serves to prevent simultaneous operation of both contactor units C1 and C2, i.e. prevent simultaneous down-ward displacement of both pairs of rods 5. Such an interlock function may be required in various contexts, for instance where the pair of contactor units C1 and C2 constitute the reverser switch means for reversing the sense of rotation of a polyphase asynchronous motor.

The improved interlocking mechanism comprises a pair of similar rocker members associated with the respective contactor units, and generally designated L1 and U2. Corresponding parts of the two rocker members are designated in the drawings by the same numerals followed by subscript 1 or 2. The ensuing description holds for either member and the subscripts will accordingly be omitted therein, except as required.

Each rocker member includes a rock shaft 8 having end trunnions 8a pivotally received in holes formed in the opposite vertical flanges 7a of the baseplate 7. Projecting from the ends of shaft 8 in parallel directions are similar lever arms 9, each of'which has a flat bearing surface 9a formed at its end in a common plane. From a point of shaft 8 somewhat displaced to one side from its midpoint is an arm 10- which projects in a direction generally opposite from that of the end lever arms 9, and at an angle thereto, as will be apparent from FIG- URES 2 and 3. The arm 10 has a boss 11 formed at its end, on theside directed towards the end of shaft 8 which is the more remote from arm 10. The configuration of boss 11'will be described later. Also projecting from the same side of arm 10 as boss 11, but at a smaller radial distance from shaft 8, is a pin 13 for anchoring one end of a tension spring as will be later described.

The two rocker members L1, L2 thus described are mounted in mutually inverted positions with their pivots 8a in the side flanges 7a of base 7, so that the two

shafts

8 and 8 are parallel in a common horizontal plane, theend arms 9 of each assembly project outwards so that the flat bearing surfaces 9a at their ends underlie the lower ends of the rods of the related contactor unit C1 or 02, While the intermediate arms 19 and are in crossed relation, as permitted by the displaced position at which each arm 10 is mounted With respect to the midpoint of its shaft '8, and the

bosses

11 and 11 are directed towards each other, so as to overlap substantially completely, as will be seen from FIGURE 1. A tension spring 12 has its ends anchored to the

respective pins

13 and 13 and urges the two'rockers in 0pposite directions about the axes of shafts 8 S specifically in the directions tending to apply the bearing surfaces 9a against the lower ends of the respective actuator rods 5.

Returning to the detailed configuration of each of the bosses 11, this includes a radially inner face 14 which is a portion of a cylindrical surface coaxial with shaft 8. To one side of this inner surface 14, the boss 11 includes a lateral surface portion 15 which is also part-cylindrical, somewhat smaller in radius than that of surface 14. In the idle position illustrated in full lines in FIGURE 2, the surface 15 of rocker assembly L is positioned so that its geometrical axis coincides with that of shaft 8 of the other rocker assembly L and similarly the surface 15 of L has its geometric axis coinciding with that of shaft 8 of L It is to be understood that the. geometric relationships just described need beapproximate only, and their reason will presently appear.

In operation, assuming the winding 2 of contactor unit C is energized, both related actuator rods 5 are displaced downward as earlier described, and their lower ends acting on the bearing surfaces 9:1 cause the rocker L to rotate as :indicated by arrow F (FIGURE 2), so I that the latter assumes the chain-line position shown at L In this movement, the inner surface 14 of rocker L has swept past the side surface 15 of stationary rocker L remaining clear of said last surface owing to the geometrical relations indicated above. In the new position of rocker L .it will be evident from FIGURE 2 that counterclockwise rotation of rocker L is prevented, since such rotation would immediately bring the side surface 15 into abutting engagement with the inner surface 14 of rocker L in its new position. Hence, downward displacement of the actuator rods5 associated with contactor unit C is positively prevented, even in case of inadvertent or erroneous energization of the winding of said contactor.

It will be noticed that since therocker L is arrested almost immediately on inception of any attempted counterclockwise rotation of it due to the small separation present between its surface 15 and the surface 14 =of the deflected rocker L in its actuated position, there will be no danger whateverof unwanted actuation. of..any...

of the contacts provided within the casings 6 of con tactor unit C even if the displacements required for such actuation are quite small. Moreover, in the even-t of energization of the winding of C in the actuated condition of C the only consequence will be the development of lateral reaction forces acting on the shafts 8 of both rocker assemblies L and L and such forces will not tend to rotate the rocker L in a direction to deactivate the actuated contactor unit C On deactivation of contactor unit C through deenergization of the winding 2 of it, the related actuator rod 5 is restored to its idle upper position, through restoring spring means not shown, whereupon tension spring 12 restores the rocker L to its initial full-line position. At this time, the other contactor unit C is free to be actuated, causing a symmetrical operation of the interlocking device quite similar to that described above.

It will be observed that in the illustrated embodiment, both rocker assemblies are identical and are simply mounted in positions that are inverted or positioned with respect to each other.

Various changes may be introduced into the construction shown and described without exceeding the scope of the invention. Thus, if the two contactor units to be associated by way of the interlock mechanism are different rather than similar as shown, the rocker assemblies may differ correspondingly. One or both of the rockers may be provided with a single end lever arm 9 instead of two, or more than two may be provided. The lever arms 9 may be actuated by parts moving in rotation rather than in axial translation as do the rods 5 shown herein. Instead of being actuated by the moving parts of the contactors by direct engagement, as herein, they may be driven through intermediate linkage, e.g. gear sectors or otherwise.

The spring 12 may if desired be made strong enough to provide simultaneously the storing spring force for restoring both contactor units to their idle condition. I

What I claim is:

1. Interlocking mechanism for preventing simultaneous displacement of two elements to respective displaced positions, comprising a pair of members mounted for rocking about parallel axes, arms projecting from the respective members in mutually crossed relation, means actuated by each element on displacement thereof to its displaced position to rock a related one of said members from a first to a second angular position in a direction tending to move the related arm away from its crossed relation with the other arm, a part on each arm projecting towards the other arm in a direction generally parallel to said axes and so positioned that with both members in their first positions said parts are clear of each other so that either member can be displaced to its second position, while with one member in its second position the projecting part thereof stands in the path of the projecting part of the other member whereby the latter cannot be displaced to its second position and spring means for urging each of said members towards its first position.

2. Mechanism according to claim 1, wherein each of said parts has a radially inner surface which as arcuate and generally coaxial with the related rocking axis, anda side surface which is arcuate and generally coaxial with the other rocking axis in the first position of the related member, said side surface of one member providing clearance for the inner surface of the other member when said one member is in its first position, and said inner surface of said one member standing in the path of said side surface of the other member when said one member is in its second position.

3. Mechanism according to claim 1, wherein the means actuated by each element to rock the related member comprise a further arm projecting from said member and engaged by said element to rock the member on displacement of the element.

4. Incombination with a pair of contactor units each having at least one contact actuating element displaceable to a displaced position in an actuated condition of the contactor unit, a base supporting both units, and interlocking mechanism comprising a pair of members mounted for rocking about parallel axes on said base, arms projecting from the respective members in mutually crossed relation, means actuated by each element on displacement thereof to its displaced position to rock a related one of said members from a first to a second angular position in a direction tending to move the related arm away from its crossed relation with the other arm, a part on each arm projecting towards the other arm in a direction generally parallel to said axes and so positioned that with both members in their first positions said parts are clear of each other so that either member can be displaced to its second position, while with one member in its second position the projecting part thereof stands in the path of the projecting part of the other member whereby the latter cannot be displaced to its second position and spring means for urging each of said members towards its first position.

5. The combination claimed in claim 4, wherein said elements are rods displaceable normally to said base, said members are supported on said base between the respective elements with each member close to its related element, and wherein said means actuated by said elements to rock the members comprise further arms projecting from the respective members in opposite directions from one another to be engaged by the related elements.

6. The combination claimed in claim 4, wherein said elements comprise a pair of rods connected with each contactor unit. and displaceable normally to said base, said members are supported on said base between the units with each member close to its related unit, and said means actuated by said elements to rock the members comprise a pair of further arms projecting from each member to be engaged by the rods of the related unit.

7. The combination claimed in claim 6, wherein both said members are similar in construction, each comprising a shaft mounted in the base for rotation about a related one of said axes, said first arm projecting radially from the respective shaft at a point thereof displaced from the midpoint of the shaft, and said two further arms projecting radially from oposite ends of said shaft in parallel directions generally away from said first shaft, the arrangement being such that with said members mounted in mutually inverted positions on the base, said projecting parts of the first arms of the respective members both lie substantially on the mid-plane of said members.

8. Mechanism according to claim 1 wherein said spring means is a tension spring interconnecting said arms.

References Cited by the Examiner UNITED STATES PATENTS 2,255,905 9/1941 Somers et al. ZOO-98 2,262,071 11/1941 Van Valkenburg 200- MILTON KAUFMAN, Primary Examiner.

Claims

4. IN COMBINATION WITH A PAIR OF CONTACTOR UNITS EACH HAVING AT LEAST ONE CONTACT ACTUATING ELEMENT DISPLACEABLE TO A DISPLACED POSITION IN AN ACTUATED CONDITION OF THE CONTACTOR UNIT, A BASE SUPPORTING BOTH UNITS, AND INTERLOCKING MECHANISM COMPRISING A PAIR OF MEMBERS MOUNTED FOR ROCKING ABOUT PARALLEL AXES ON SAID BASE, ARMS PROJECTING FROM THE RESPECTIVE MEMBERS IN MUTUALLY CROSSED RELATION, MEANS ACTUATED BY EACH ELEMENT ON DISPLACEMENT THEREOF TO ITS DISPLACED POSITION TO ROCK A RELATED ONE OF SAID MEMBERS FROM A FIRST TO A SECOND ANGULAR POSITION IN A DIRECTION TENDING TO MOVE THE RELATED ARM AWAY FROM ITS CROSSED RELATION WITH THE OTHER ARM, A PART ON EACH ARM PROJECTING TOWARDS THE OTHER ARM IN A DIRECTION GENERALLY PARALLEL TO SAID AXES AND SO POSITIONED THAT WITH BOTH MEMBERS IN THEIR FIRST POSITIONS SAID PARTS ARE CLEAR OF EACH OTHER SO THAT EITHER MEMBER CAN BE DISPLACED TO ITS SECOND POSITION, WHILE WITH ONE MEMBER IN ITS SECOND POSITION THE PROJECTING PART THEREOF STANDS IN THE PATH OF THE PROJECTING PART OF THE OTHER MEMBER WHEREBY THE LATTER CANNOT BE DISPLACED TO ITS SECOND POSITION AND SPRING MEANS FOR URGING EACH OF SAID MEMBERS TOWARD ITS FIRST POSITION.