US3167626A - Normally closed auxiliary contact device including a slide member provided with fast acting contact means - Google Patents

Description

Jan. 26, 1965 Filed Oc-t. 5, 1962 ROCHETTE ETAL ILIARY CONTACT DEVICE INCLUDING A ED WITH FAST ACTING CONTACT MEANS 2 Sheets-Sheet 1 a I I9 3a 6 d, O O 49 a a f9 /2 20 E: Z 23 OH g- EU 4 Q g Mew WAAMW Jan. 26, 1965 J. P. ROCHETTE ETAL 7,6

NORMALLY CLOSED AUXILIARY CONTACT DEVICE INCLUDING A SLIDE MEMBER PROVIDED WITH FAST ACTING CONTACT MEANS 2 Sheets-Sheet 2 Filed Oct. 5, 1962 United States Patent ()ffice 3,167,626 Patented Jan. 26, 1965 3,167,626 NORMALLY CLOSED AUXILIARY CDNTACT DE- VICE INCLUDING A SLIDE MEMBER PROVEDED WiTH FAST ACTING CONTACT MEANS James P. Rochette, Nanterre, and Robert A. R. Caudron,

Meudon, France, assignors to La Telernecanique Eisetrique, Nanterre, France, a company of France Fiied Get. 5, 1962, Ser. No. 223,656 Claims priority, appiication France, Oct. 13, 1961, 875,859 6 Claims. (Cl. 260-404) This invention relates to a normally closed auxiliary contact device having a fast action and adapted for electromagnetically operated electrical apparatus, for automatically reducing the energizing current applied to the elec tromagnet windings after initial energization of the electromagnet to operate main contacts associated therewith.

It is well-known in the art that once an electromagnet has been initially energized to operate one or more contacts associated therewith, a substantially lower rate of current flow through the windings becomes suflicient in order to maintain the electromagnet energized and hold said contacts in operated condition. It is, therefore, desirable to provide some suitable means to achieve this result automatically, and for this purpose it is well-known to provide an auxiliary contact operated by the electromagnet and adapted to connect resistance into the energizing circuit thereof in order to reduc the current flow therethrough once the main contacts have been effectively operated.

However, considerable practical problems arise in the construction of an entirely successful auxiliary contact device of this kind, and objects of this invention are to provide a fast-acting contact device that will be especially well-suited in meeting the stringent practical requirements encountered in the field of use just stated.

One object of the invention is to provide such a contact device which will not operate until the electromagnetically displaced element, such as an armature, has reached a point in its displacement very close to its final position, and will then operate quickly and positively and reliably. Another object is to provide such a fastacting contact device which will be positively snapped to its operated condition by the kinetic acquired by it in the initial stage of its displacement. The advantage accompanying the attainment of this last object is that, otherwise, the sudden reduction in electromagnetic attraction force would tend to prevent the armature from reliably reaching its final position, and the return spring means normally provided would pull back the armature to re-close the auxiliary contact and restore the full value of energizing current, thereby instituting unstable operation of the system, involving continued back-and-forth reciprocation in the manner of a D.-C. electric bell. It is, therefore, a specific object of this invention to improve the operating stability of electromagnetic apparatus of the type disclosed.

The fast-acting contact assembly of the invention, as will presently appear, is readily adjustable so as to be operated (e.g. to its open position) at an instant where the electromagnetically actuated element, e.g. armature, has very nearly attained its final position; at the same time, however, a positive, clearcut contact-opening action is attained with a wide spacing between the contacts in the final condition of the device.

The features of novelty of the invention will be apparent from the ensuing description thereof made with reference to a specific exemplary construction and application thereof, to be considered as illustrative rather than restrictive.

In the accompanying drawings:

FIG. 1 is a schematic showing of conventional electromagnetic contactor apparatus including main contacts and auxiliary contacts serving to introduce auxiliary resistance into the electromagnet energizing circuit and this figure serves to illustrate a preferred field of use of the invention.

FIG. 2 is an elevational view, partly in section, of a fast-acting contact device according to the invention usable as the auxiliary contacts designated as E in the diagram of FIG. 1.

FIG. 3 is an elevational view of an electromagnetic contactor system according to the basic diagram of FIG. 1, and embodying the fast-acting contact device of FIG. 2 as an auxiliary contact device therein; and

FIG. 4 is a view on line IV-IV of FIG. 3.

As diagrammatically illustrated in FIG. 1, the electromagnet C of a contactor device or the like is connected with a D.-C. source B and a switch A so as to be energized on closure of the switch. The contactor electromagnet controls the condition of a set of main switch contacts such as D1, D2, D3 and an auxiliary switch contact E. Auxiliary switch E is connected across a resistor R. Thus, as the electromagnet is energized to close the main D contacts, the auxiliary switch E is opened so as to connect resistance R into the electromagnet energizing circuit. The energizing current applied to the electromagnet windings through resistance R, while being lower than the current required to operate main contacts D, is still suflicient to maintain the energization and hence hold the main D contacts in their closed condition.

When the energizing circuit is opened, as by opening the switch A or another switch, the electromagnet is completely deenergized and the main contacts are opened, while the auxiliary switch E is closed, thereby conditioning the contactor system for a fresh operating sequence.

in accordance with the present invention, the auxiliary switch E is constructed in a preferred embodiment as shown in PEG. 2. The illustrated device comprises a generally rectangular housing 1 made of insulating material. Movably mounted in the housing is a slider member 3 having an outer end portion 3a projecting through an opening in a side of the housing. The member 3 is made of insulatin material, and is rectangular in cross section. It is slidable in suitable bearing surface such as 1:: and 1b of housing 1. A spring 2 acting between an end Wall of housing 1 and an inner end surface of the member, urges the latter to a projecting position.

Adjustably positioned within a transverse recess formed in the slider member 3 is a block 4 of insulating material formed with an outwardly jutting arm 4a. The relative position of the block and slider member is adjustable by means of a se screw 5 having a head 5a seated in a recess formed in the outer end 3a of the slider, and a spring 6 urges the screw towards its seated condition. The threaded end 5b of the screw has an outer diameter somewhat greater than the shank of the screw, and is force fitted in a smooth passage formed in block 4, preventing spontaneous unscrewing. The siider 3 is further formed with another transverse recess through which a lever 8 extends, the lever being formed from a suitably conformed strip of metal. A spring 9 seated against a surface of the slider 3 and the under surface of the lever 8 around a centering post 10 urges the lever upwards relatively to the slider.

Transverse displacements of lever 8 relative to the housing 1 and slider 3 are restricted, in one direction, by a cylindrical rod 11 secured as by solder to a lower surface of the lever and projecting at both ends beyond the side walls of the recess in the slider in which said lever is movable, and in the opposite direction by a stop portion 12 cut out of the strip constituting 8 and bent down laterally to provide a cam portion 12a as will presently appear.

The lever 8 at its left hand end according to the drawing is fitted a clearance fit into a cavity 13 formed in the adjacent wall of the housing 1, so as to be pivot-ally rotatable about a fulcrum provided by an edge 14 at the entrance to said cavity. Excessive angular displacement of lever 8 in the cavity 13 is prevented by a boss 8a provided on said lever, as by stamping and deforming a portion of said lever, which boss is adapted to abut against an opposite wall of cavity 13.

The lever 8 is electrically connected by means of a flexible braided tape 15 of conductive material to a fixed terminal 16 constituted by a metal strip fitted into a cavity 17, similar to cavity 13 formed in the housing near its upper end. At its opposite end projecting beyond the slider 3 the lever 8 is provided with a contact 18 cooperating with a fixed contact 19a provided at the end of a stationary contact arm 19 also formed as a strip fitted into a further cavity formed at an appropirate position in the housing.

The housing 1 further includes an additional cavity 21 generally similar to the cavities mentioned above and formed in a lower part of the housing below cavity 13, and a further stationary contact arm 23 is fitted therein for reasons that will presently appear.

The housing 1 is further shown provided with smooth holes 24 for receiving studs or rivets for attaching a cover plate over the housing; a positioning pin 25 projecting from the lower end of the housing for mounting-location purposes; and a threaded mounting screw or stud 26 (also see FIG. 4) is provided, engaging in a lug 1c projecting laterally from the base of the housing.

In operation, assume the extremity 27 of an electromagnet armature, shown in chain outline in FIG. 4, is displaced in the direction indicated by arrow F due to attraction of the armature on energization of the associated electromagnet winding (not shown), into engagement with the upper end 3a of slider 3. The armature 27 travels a certain distance before engaging the surface of the slider, and then depresses the slider in opposition to spring 2 which is thereby compressed. The resulting downward movement of slider 3 has no eifect so long as the finger 4a has not engaged lever 8. The engagement of finger 4a with the upper surface of the lever 8 however occurs with a point of the lever very near the pivotal fulcrum 14, and the lever is then immediately rocked in the direction of arrow F1 at a very rapid rate and with a large amplitude for a small-amplitude displacement of the finger 4a after it has engaged the lever. This rocking movement of the lever 8 is not interfered with by the stop-cam 12, because its outer edge surface 12a is cut to the shape of a circle-involute, adapted to engage rollingly a flat surface of housing 1, parallel to the direction of slider displacement.

It will be noted that manipulation of set screw permits a highly accurate adjustment of the position of finger 4a with respect to the head 3a of slider 3, and hence the point at which finger 4a engages the lever 8. At the same time however, the spring 6 by which the block 4 is resiliently held within its recess in the slider 3, is adapted to be compressed should the displacement of the slider after engagement of the block with the lever 8, exceed the amount required to cause a full-amplitude rocking movement of lever 8. The lever therefore is not liable to be damaged by finger 4a in the event of an excessive downward force exerted on the slider 3 by electromagnet armature 27. In such an event, after the block 4 has been arrested in its downward movement by the lever 8, the spring 6 is compressed and reacts against the slider 3 in the same direction as the action of the spring 2 on the slider.

It should further be noted that during the downward displacement of the slider 3 (in FIG. 2), as the spring 2 becomes more and more compressed, spring 9 becomes gradually released, so that at the instant that finger 4a engages lever 8, the separation between contacts 18 and 19 occurs readily and lightly, and moreover, the now fully relieved spring 9 does not exert any opposing force on the lever 8 in its rocking movement.

FIGS. 3 and 4 illustrate the use of the switchbox just described as embodied in contactor apparatus of the general type disclosed diagrammatically in FIG. 1. It will be noted that in these figures the housing 1 of the switchbox described is illustrated in outline. In its mounted condition, the stationary contacts 16, 19 and 23 previously mentioned are blocked in their respective positions by means of suitable adhesive material such as a synthetic resin. Further, the contacts 16 and 23 are shown electrically interconnected by a U-shaped connector strap 28 externally of the housing 1. An auxiliary resistor R corresponding in function to resistor R in the diagram of FIG. 1, provided as a generally cylindrical unit, is clamped between a pair of spaced clamping collars 30-1 and 33-2, of conductive material, respectively connected by means of a rigid connector 32 with contact terminal 23, and a rigid connector 31 with contact 19. All the connections are rigidly blocked in position by screws 29.

It will be understood that the conductive path provided by the serial connections 1628-323i in FIGS. 2-4, corresponds to the connecting line 33 in the diagram of FIG. 1, and similarly the serial connecting path 19 31-39 corresponds to connecting line 34. With this in mind, no further description is believed necessary of the manner of operation of the apparatus shown in FIGS. 2-4, and it will be readily seen that when the assembly illustrated in FIGS. 3 and 4 is connected in circuit with an electromagnet winding associated with the armature 27, there is provided a system wherein the electro-magnet holding current is automatically reduced with respect to the energizing current, after the main contacts associated with the electromagnet have operated.

It will be readily understood that various changes and modifications may be made in the structural details of the components shown and described without exceeding the scope of the invention. It will also be apparent that the fast-acting contact device as illustrated in FIG. 2 of the drawings may find various practical uses other than in connection with the reducing of the energizing current in an electromagnet winding of a contactor system.

What we claim is:

1. A normally closed auxiliary contact device comprising a casing; a stationary contact supported in said casing; a lever pivoted on a fulcrum in said casing and having a movable contact thereon for cooperation with said stationary contact when the lever is rocked in one direction; a member slidable in said casing and displaceable in the opposite direction; return spring means acting between said casing and member for urging the member in said one direction; contact spring means acting between said member and said lever and urging said lever in said one direction for engaging said movable contact with said stationary contact; an actuating part carried by said member and engageable with a portion of said lever adjacent said fulcrum to rock said lever oppositely, to move the movable contact in said opposite direction to separate said movable contact from said stationary contact on displacement of the member in said opposite direction; and further spring means acting between said member and part to urge said part in said opposite direction relative to said member into a seated position in which said part is rigidly abutted against said member.

2. A device according to claim 1, further comprising threaded means for adjusting the seated position of said actuating part with respect to the member.

3. A contact device according to claim 2, including a transverse through-recess formed in said member and having said lever freely extending therethrough, an internal edge surface in said casing on one side of said member providing said fulcrum for the lever, and wherein said movable contact is carried on an end portion of said lever beyond the opposite side of said member; and

further comprising stop means carried by said lever and respectively engageable with said casing and said member for limiting transverse displacement of the lever with respect to said member. I

4. A device according to claim 3, wherein one of said stop means has a contour in the shape of an involute of a circle and is engageable with a surface portion of the casing parallel to the displacement of said member in the casing.

5. A device according to claim 1, wherein said actuating part is positioned Within a recess formed in said member for displacement therein parallel to the displacement of said member.

6. A device according to claim 1, further comprising a screw threadedly engaging said part and having a 6 shoulder portion engaging said member, and adjustable to adjust the seated position of said member, and wherein said further spring means is arranged to urge said part and screw in a direction to seat said shoulder portion against said member.

References Cited by the Examiner UNITED STATES PATENTS 137,730 4/73 Smith 317-157 1,242,763 10/17 Bossu 317157 3,005,890 10/61 White et a1 200-l04 3,076,075 l/63 Colvill 200104 BERNARD A. GILHEANY, Primary Examiner.

Claims (1)

1. A NORMALLY CLOSED AUXILIARY CONTACT DEVICE COMPRISING A CASING; A STATIONARY CONTACT SUPPORTED IN SAID CASING; A LEVER PIVOTED ON A FULCRUM IN SAID CASING AND HAVING A MOVABLE CONTACT THEREON FOR COOPERATION WITH SAID STATIONARY CONTACT WHEN THE LEVER IS ROCKED IN ONE DIRECTION; A MEMBER SLIDABLE IN SAID CASING AND DISPLACEABLE IN THE OPPOSITE DIRECTION; RETURN SPRING MEANS ACTING BETWEEN SAID CASING AND MEMBER FOR URGING THE MEMBER IN SAID ONE DIRECTION; CONTACT SPRING MEANS ACTING BETWEEN SAID MEMBER AND SAID LEVER AND URGING SAID LEVER IN SAID ONE DIRECTION FOR ENGAGING SAID MOVABLE CONTACT WITH SAID STATIONARY CONTACT; AN ACTUACTING PART CARRIED BY MEMBER AND ENGAGEABLE WITH A PORTION OF SAID LEVER ADJACENT SAID FULCRUM TO ROCK SAID LEVER OPPOSITELY, TO MOVE THE MOVABLE CONTACT IN SAID OPPOSITE DIRECTION TO SEPARATE SAID MOVEABLE CONTACT FROM SAID STATIONARY CONTACT ON DISPLACEMENT OF THE MEMBER IN SAID OPPOSITE DIRECTION; AND FURTHER SPRING MEANS ACTING BETWEEN SAID MEMBER AND PART TO URGE SAID PART IN SAID OPPOSITE DIRECTION RELATIVE TO SAID MEMBER INTO A SEATED POSITION IN WHICH SAID PART IS RIGIDLY ABUTTED AGAINST SAID MEMBER.

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