US3457532A

US3457532A - Electromagnetically operated mechanisms,particularly contactors

Info

Publication number: US3457532A
Application number: US608795A
Authority: US
Inventors: Guy H Lacan; Maurice G Contal
Original assignee: Telemecanique Electrique SA
Current assignee: Telemecanique SA
Priority date: 1966-01-12
Filing date: 1967-01-12
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22
Also published as: DE1564933B2; GB1166638A; BE691400A; DE1564933A1; CH449119A; AT281172B; LU52655A1; FR1470393A; ES335550A1; NL6700196A; SE334407B; NO121105B

Description

July 22, 1969 G LACAN ET AL 3,457,532

ELECTROMAGNETICALL? OPERATED MECHANISMS, PARTICULARLY CONTACTORE Filed Jan. 12, 196? 3 Sheets--Sheet 1 I INVENTOIS Guy H. LACAN Maurie. CONTAL ATTORNEY i 1969 e H. LACAN ET AL 3,457,532

ELECTROMAGNETICALLY OPERATED MECHANISMS, PARTICULARLY CONTACTORS Filed Jan. 12, 1967 5 Sheets-Sheet 2 Fig.5

INVENTORS Guy H. LACAN Mnuric G. I. CONTAL July 22, 1969 G LACAN ET AL 3,457,532

' ELECTROMAGNETICALLY OPERATED MECHANISMS, PARTICULARLY CONTACTORS 7 Filed Jan. 12, 1967 5 Sheets-Sheet 3 l/V VEN'I'OKS F|g.8 Guy H. LACAN Muul'ice G. CONTAL W A T'I'UR NI'I Y United States Patent 3,457,532 ELECTROMAGNETICALLY OPERATED MECHA- NISMS, PARTICULARLY CONTACTORS Guy H. Lacan, Carrieres-sous-Bois, and Maurice G.

Contal, Paris, France, assignors to La Telemecanique Electrique, Nanterre, Hauts-de-Seine, France Filed Jan. 12, 1967, Ser. No. 608,795 Claims priority, applicatitgsFrance, Jan. 12, 1966,

Int. Cl. from 3/28 US. Cl. 335-189 12 Claims ABSTRACT OF THE DISCLOSURE This invention relates to electromagnetieally operated mechanisms in particular contactors, which are of improved mechanical construction and are easily fitted.

The invention is generally applicable to electromagnetically operated mechanisms in which an armature moves contact parts or a mechanical device through the intermediary of a rocking lever to which the armature is attached by a hinge.

There is already known a contactor comprising a core plunger forming an armature which is articulated on a rocking lever which, in turn, operates a sliding contact carrier whose movement is opposite and parallel to that of the plunger. This form of contactor possesses an advantage that it effects balance between the parts in motion and thus provides apparatus not affected by shocks and vibrations. In addition, it is possible to dismantle either the coil, or the contact-carrier in parallel from the same side of the apparatus. This form of construction however has one disadvantage: the armature on one hand and contact-carrier on the other hand, are sliding parts guided by slots or similar means along their entire length of travel, while the heads of the lever to which they are connected have a circular movement. A sliding movement at the articulation point is necessary, and this is achieved by means of cut-outs or elongated holes, or by means of forks supporting rods fitted with collars.

This kind of articulation introduces play and wear in moving parts subjected to alternating movement and frequently operated. In addition, guiding means of high quality material is required for sliding parts. The contactcarrier and armature demand diflicult, high quality manufacture of the parts of the mechanism under conditions of mass production.

Finally, in the usual constructions in which the electromagnet is placed at the side and in parallel with the system of contacts, the contactor being capable of being mounted on a vertical board, two types of construction are generally necessary: one with the electromagnet to the left of the break contacts, the other with the opposite arrangement, so as to be able to provide a changeover switch having the two electromagnets side-by-side and interlocked in the usual manner so that the two parts of the changeover switch cannot close the electrical circuit together.

The present invention seeks to remove these disadvanice tages and bring about operational reliability by eliminating as far as possible the causes of friction and wear.

A further object of the invention is, moreover, to provide an electromagnetically operated mechanism which is quite symmetrical about the median plane of the electromagnet and of the contact system, so that two mechanisms of the same construction, one of which is turned by on its support base, can constitute a changeover switch.

The basis of the invention is the principal idea that, contrary to the form of construction previously mentioned in which the rocking lever is only a transmission member with play between the two duly sliding parts, it is the rocking lever which, by well-fitted hinge articulations supports the armature and the part utilizing the movement, a strict translation movement of driving and driven parts being not necessary, provided that on the one hand, the meeting of pole surfaces of the electromagnet, and on the other hand, the closing of movable contacts on their stationary contacts, are both correctly ensured from the me chanical and electrical points of view by centering means which prevent deviations of these parts in relation to their median plane of translation parallel to the axis of the rocking lever.

In accordance with a first embodiment of the invention, an armature of an electromagnet articulated to exercise a driving torque on a lever is characterized in that it is provided at its far end from its pole surfaces, with well fitting means pivoting about an axis parallel with the axis of rotation of the lever, that at least a second lever whose movable end acting on a part of the armature in the vicinity of the pole surfaces of the latter centers the meeting of the said surfaces of the armature with those of the yoke of the electromagnet, and that the second lever is compelled to accompany the armature by reason of the projection of one sliding in a slot of the other.

Preferably, the second lever is placed in a plane parallel to the axis of rotation of the rocking lever, and laterally with regard to master plates of the electromagnet, and for centering the armature, a pair of levers are provided which are connected by a central branch and forming a harness around the armature.

If the armature is of a considerable weight, it is useful to form the moving end of the second lever as a skate which supports a lateral projection of the armature by rolling over it, the object of this support being to diminish the strains on the pivots under the Weight of the armature. To advantage, two symmetrical pairs of levers or harnesses can be provided, which are symmetrical about a transversal median plane of the magnetic circuit of the electromagnet, and provide, on each harness, two groups of rolling surfaces, so that the forces exercised by the armature on the accompanying levers are perfectly balanced for any armature position. It is thus possible to construct a contactor embodying the invention which can operate just as well if it is turned upside down on its vertical attachment base, as has been previously mentioned. The accompanying levers or harnesses can, in addition, be employed to transfer the movement of the armature to the auxiliary contacts in accordance with normal practice in the field of contactors.

In another embodiment of the invention, a movable contact support, receiving from a lever .a driving torque and moving in a manner practically parallel to itself by being connected to the said lever by pivoting means, is constituted by a part comprising parallel contact columns in insulating material, only one means of centering being provided on the far side from the pivoting axis on the column.

-In another embodiment of the invention, the rocking lever consists of two equal and symmetrical parts joined in the middle in the longitudinal plane of the lever, their branches moving away from that plane to form, when they are joined, a double fork, each part comprising, towards the middle a pivoting axis and at one end, a trunnion directed away from the axial plane, and, at the other end, a hole for trunnion, so that the two parts of the lever can be fitted by their respective trunnions or holes into the corresponding parts of the armature and of the support of the movable contact and so that the mechanism thus constituted as one unit can then be fixed by its central axis into the base of the contactor.

By way of example only, embodiments of the invention will now be described in greater detail with reference to the accompanying drawings of which:

FIG. 1 is a perspective view of an assembly of the main parts of a first embodiment,

BIG. 2 is a perspective view of a different form of one component,

FIG. 3 is a perspective view of one of the parts of the embodiment of FIG. 1,

FIG. 4 is a view partly in section of the first embodiment with its base plate removed,

FIG. 5 is a part cross-section on the line VV of FIG. 4,

FIG. 6 is a perspective view of a part forming detachable bearing of the first embodiment shown opposite a portion of the base in which it fits,

FIG. 7 is an end view with, on the left, a cross-section on the line V\IIVII of FIG. 5, and,

FIG. 8 is a cross-section on the line VIII-VII-I of FIG. 5.

In FIG. 1, for the sake of clarity, certain support parts and all the parts of the electrical contacts have been excluded as have all detail parts.

The electromagnet consists of a yoke 1 supported in a fixed manner by a support (not shown). On one branch of the yoke there is an energizing winding L1-L2 shown schematically. On energization the magnetic field draws an armature 2 towards the yoke in the direction of the arrow F1, the armautre being provided at the rear with two spaced extensions 2a which contain, on the axis 01-02, bearings (not shown) in which trunnions 6 of a rocking lever 4 are mounted.

The rocking lever turns about a fixed axis 03-04 and is articulated about an axis 05-06 to a contact support unit 30. The armature 2 and the contact support unit 30 are thus compelled to carry out parallel movements in opposite directions.

It is easy to see that the attraction forces acting on the armature are perpendicular to the pole surfaces, such as S1, of the yoke and S2 of this armature, and that they automatically exercise a centering effect in the direction of the plane passing through X1-X2, plane which is parallel to the axis 03-04 of the rocking motion of the lever. It is, however, necessary to guide the armature during its return movement, and even during its closing movement, against the effects of external forces such as shocks or gravity, if the apparatus is not quite horizontal. To provide this guiding, a lever 11 is provided and it acts as a prop in the vicinity of the pole surfaces of the armature. When the electromagnet is part of a contactor, it is found that the angular movement of trunnion 6 is only about 8 on either side of the mean axis of oscillation. In relation to a strict translation of the armature along axis X1-X2, the deviation is small. It is thus sufficient to support the armature during movement by the lever 11, which supports at its fork-like end 11a, a pin 12 mounted on a master plate (not shown) of the armature, and which pivots about its axis which is integral with the support (not shown). The pin 12 has a head 16 which prevents deviation of the armature in the two directions perpendicular to the plane passing through axis X1-X2.

In a preferred construction, two other levers 13 and 14 are employed, which pivot in the fixed support about an axis 07-08, the levers being provided with heels connected by a cross-bar 17, in such manner that the assembly constitutes a harness. The ends of levers are forked at 13a and they each enclose a pin 15 on the armature. The cross-bar 17 could be employed to operate auxiliary contacts, as will be shown later on.

It will be noted that the rotation of the levers 13, 14 of the harness is in parallel planes, while the movement of the armature connected by trunnions 6 to the lever 4 is theoretically not exactly parallel to itself, that is to say that the translation of

pins

12 or 15 can be slightly oscillatory.

For good functioning of the system, a small amount of play is required between the branches of the harness and the armature, and also between the pins and the forks of the levers. But, as has already been said, only a centering sufficient for directing the pole surfaces of the armature is sought, given that the forces of attraction which act on the said surfaces increase very rapidly when air gap diminishes. Due to presence of a lever such as 11, or of a harness comprising two levers 13, 14, acting as centering props, the friction is only the friction of surfaces which turn, and acts over a very small area.

These arrangements result in the removal of the friction, which previously occurred along the length of the lateral slide used in the earlier devices, and that in addition, play is only introduced on the lateral centering parts and not on the main parts transmitting the forces of the electromagnet.

The contact support unit 30 is a moulded part which oscillates around an axis 05-06 forming an articulation axis with branches of the lever 4. The support unit 30' comprises three contact of

columns

31, 32, 33 (see also FIG. 5). The unit has trunnions 26, 27 which fit closely into openings 7 in the lever 4, and it would not normally be possible to guide the support unit 30 in lateral grooves. However, in this embodiment of the invention, two bars 45a, 45b have been provided to effect centering of the column 32.

Similarly to the armature, the parallelism of movement of support unit 30 is not exact, and some lateral play of bars 45a-45b is necessary, but this is not important, since the forces transmitted to the support unit 30 are large only when the movable contacts 56 come to touch stationary contacts 57 (FIG. 8). Thus there is only a very low and very limited friction, and there is no play in the principal articulations.

As can be seen in FIGS. 1 and 3, the rocking lever 4 is constituted by two cast parts-which are assembled in the longitudinal plane by surfaces 8. Each part has arms 4a, 4b, bending outwards to constitute half-forks. The arms 4a have trunnions 6 directed outwards. The arms 4b have openings 7 provided to receive, on the axis 05-06, the portions of shaft carried by the contact support unit 30, which forms at its base a spider 30b. At the center of this spider there is a boss 30a upon which acts a helical spring 54 (FIG. 5) ensuring the return of the mechanism when energization of the electromagnet ceases.

In another construction shown in FIG. 2 each branch of the harness has a rolling surface 19, while pin 12 moves the lever by means of a slot or elongated hole 22.. The armature is provided with lateral projections 20 whose flat surfaces roll on surfaces 19. This form of construction is particularly suitable when the electromagnet has large dimensions, i.e., when the armature is relatively heavy. The surfaces 19 support the weight of the armature and thus diminish the strain on the trunnions 6. In this form of construction, the armature 2 is connected to the lever 4 as in the previous case along axis 0'10-012. Irrespective of whether the harnesses are constructed in the form shown in FIG. 1 or in the form shown in FIG. 2, it is advantageous to carry out a symmetrical assembly with two harnesses, since the effect of holding down and centering is assured, whatever be the final position of the assembled electromagnet.

The movable mechanical parts: armature 2, the harnesses 17, the rocking lever 4 and the contact support unit 30 are preferably pro-assembled to'be later put in place in the framework of the contactor. The latter comprises a metal base plate 52 (FIG. 5) which supports two rightangled parts 40 for the electromagnet, and an insulating base 51 for a switching device. It is to be noted that the surfaces subjected to turning friction have been the subject of particular precautions in their construction. In FIG. 4, the cross-sections of parts carrying these surfaces have been marked with thick lines. The armature 2 is extended rearwards by two extensions 2a, which enclose two blocks 36 of plastics material, which are also retained in the longitudinal direction by the magnetic plates 37.

A cut-out 36a, combined with the rounded ends of the blocks 36, forms a bending strip giving a better flexibility to centering of the armature in relation to the trunnion 6 of the lever 4.

The pivot of the lever 4 is preferably in the form of a trunnion 5 and is an integral part of the lever half. The bearing receiving this trunnion is a block of plastics material 21 (FIG. 6) whose details will be explained later on. The half-levers have, at the end 4b, a cap with a blind hole 7 open on the side of the axial plane of the lever 4. In each blind hole 7 is placed an anti-friction packing 35 which receives in its turn the trunnions 26, 27 of the support unit 30. On the side of the branches 4a of the rocking lever, the width of the work shown at M (FIG. 4) has been made sufficiently larger than the total thickness at this location of the branch and of the trunnion, so that accurate fitting of the lever in the armature can be accomplished. For this blocks 36, being wedged in the armature, are first engaged separately with the trunnions 6, the two half-levers not being yet joined and sufficiently turned one from the other. Then, the two half-levers are turned around the trunnions 6, so that surfaces 8 are joined together, while lugs 24a, 245 on one half-lever engage corresponding holes in the other half-levers, and the lugs of the latter enter into holes 25a, 25b of the first half-lever. At the same time, the ends of the branches 4b of the lever, provided with their packing, have enclosed the trunnions 26, 27 of the spider of theysupport unit 30. Thus, the direction of fitting of trunnions away from the plane of the joint on the side of electromagnet and towards the plane of the joint on the side of the movable support, ensures simple assembling conditions with a minimum of parts. It is sufficient to have only one screw or rivet (not shown) in the transversal opening 4a of the lever 4 to maintain together the principal parts of the mechanism. To place the latter in the base 51, the pivots 5 of the lever being provided with their detachable bearing 21, the mechanism is slid through the rear of the support, the bearings 21 entering by ribs 21c, 21d into a slot 51a, as per the arrow F2 (FIG. 6). The body 21a of the bearing maintains in an opening 21e the trunnion 5 and is in contact with a reinforcement 51b of the base. In addition, when the mechanism is thus fixed in the base 51, a return spring 54 can be mounted on the boss 30a of the support of movable contacts a rear plate 52 fixed on the base having a seating collar 52a for the spring. At the same time the plate 52 is pressing against the projection 21b of the bearing 21, this projection bearing hollow to make it flexible in the direction of the arrow F2.

The base 51 can receive, as shown in FIGS. 5 and 8, an arc case contained in a cover 46, the cover and the base being fixed together by the

projections

46a and 51c opposite to each other. The base and the cover form three parallel channels in which move

branches

31, 32, 33 of the movable contacts support unit. The central channel receiving the branch 32 is provided with an anti-friction ring 45 of generally rectangular form, and of which only sides 45a, 45b, provide lateral support to the external faces of the branch 32, it being understood that all the other parts of the branches pass freely in the correspond ing channels. The end 58 of the central branch 32 can be 6 provided with bevelled edges 58a to facilitate assembly. As is usual, the are case comprises three separate switching chambers 47 with a device 47a for dividing the arcs fixed to the refractory plates 48 with vents 48a, The support columns 30 are provided with windows 33a whose base has a notch 55 of V-shape in the axial plane of support. In each window is mounted a movable contact 56,'itself of V-shape, and which is pressed against the said notch by a support member 49. This member has, on its base, a lug engaging the folded metal part of the movable contact, and it carries, at its top, a collar supporting spring 50 which seats at its other end on a boss 33b of the window. To the V-shape of the movable contact corresponds a parallel arrangement of the studs of the stationary contact 57 which are joined to the connecting parts 60 mounted on either side and trausversally on the base 51 by means of

screws

59, 61. It is to be noted that the direct support of movable contacts 56 in the manner of a knife on the notches of the windows (FIG. 8) in a balanced manner on the longitudinal plane of support unit 30 facilitates centering of the support.

FIGS. 5 and 7 show how the electromagnet of the contactor can be assembled. When the right-angled parts 40 are mounted on the base plate 52, they form

bearings

27a, 27b, 28a, 28b for the trunnions of the harnesses which are also provided with anti-friction lining 23. Preferably, the harnesses can be constructed entirely in an anti-friction plastics material. The right-angled parts 40 comprises folded feet 40a parallel to the base plate, and on them is mounted the stationary part of the magnetic circuit of the electromagnet.

The core 1 is mounted in the moulded body 43 through the intermediary of a plastics lining 61. This lining allows passage of the two arms 9 of the core 1 while it carries in its middle a distance piece '18 forming a tightening buffer for the central arm of the core 1. It comprises also two lateral feet 62 for attachment to the moulded body. The moulded body 43 forms also an enclosure for coils 63 which, in a known manner, are placed on each arm of the core. The moulded body incorporates also terminals 65 of the coil. A cover 42 supports by flexible plate 41 the core 1 on the body 43 and is screwed in the feet 40a. After their insertion in the cover 42 and feet 62, the screws 44 are provided with offset rim 34 to make sure they cannot be lost. At the base of the right-angled parts 40, a resilient pad 64 is placed to act as a stop in the rest position of the armature.

As has already been mentioned, one of the centering harnesses is made up of two lateral levers 13, 14 and of a central cross-bar 17. The cross-bar has notched

faces

17a, 17b, forming a bevelled edge at their intersection, so as to act more accurately on the push button of an auxiliary contact 53 of a known type which is mounted on the plate and its operating push button 53a receives on the upper face the push of the cross-bar 17 of the harness.

Thus, the harnesses have a double use-for centering and for transmission of movement of the armature. As opposed to known contactors in which the auxiliary contacts are operated directly by the support of movable principal poles, in embodiments of the present invention a separate transmission is employed. This is advantageous, as while suitably calculating the ratio of the arms of the lever such as 13b and 13c, it is possible to obtain a travel of auxiliary contacts which may be different from that of the principal poles, this being due to the fact that they are not subjected to the same electrical conditions.

It is easy to see in FIGS. 4 and 5 that the illustrated apparatus is entirely symmetrical about a longitudinal plane of the forks of the rocking lever 4. A second contactor turned through can be positioned in such a manner that the two electromagnets are next to each other, the two switching devices forming then a changeover switch which, in a known manner, crosses two phases of three-phase supply. To avoid a short-circuit,

should the two contactors be closed at the same time, a usual interlocking device can be placed between two cross-bars such as 17 of the neighbouring harnesses.

There could be many possible adaptations and constructions of the devices described only as an example, they could be modified by substitution of equivalent technical means without going beyond the scope of the appended claims. It is possible in particular to change the number and the form of the centering levers and of the contact surfaces with the armature, to change the form and the direction of the means of pivoting, as wellas those of the arms of the rocking lever, or those of centering means of the movable support of contact.

We claim:

1. An electromagnetically operated mechanism comprising:

a frame;

an electromagnet including a yoke mounted on said frame;

an armature movable towards said yoke in a pre-determined plane of translation when said electromagnet is energized;

an operating lever mounted for rotation about an axis on said frame and having one end thereof connected for articulation to said armature;

a movable contact support connected for articulation to the other end of said operating lever, and

at least one second lever pivotally mounted on said frame on an axis perpendicular to said plane of translation and acting on at least one surface of the armature adjacent its poles to prevent any substantial deviation of the armature with respect to said plane of translation, said second lever being arranged to follow the movement of the armature.

2. A mechanism as defined in claim 1, wherein said second lever has a slot in one end thereof and wherein the armature has a pin on said one surface engaging said slot.

3. A mechanism as defined in claim 1, wherein said second lever has one end thereof in the form of a skate, and wherein the armature has a fiat surface contacting said skate for supporting said armature.

4. A mechanism as defined in claim 1, wherein two second levers are provided, said two second levers being positioned to form a harness enclosing the armature.

5. A mechanism as defined in claim 4, wherein said two second levers are arranged symmetrically in relation to the plane of translation of the armature.

6. A mechanism as defined in claim 1, wherein said movable contact support comprises at least one column of insulating material movable in said frame with freedom of rotation with respect to the articulation point of the movable contact support on the operating lever, and further comprising two bars secured to said frame, said bars being made of anti-friction material and placed against the lateral faces of said column in the vicinity of the contacts for restricting said freedom of rotation.

7. A mechanism as defined in claim 1, wherein the armature has two extensions on the side thereof which is opposite to its poles, said extensions forming a fork-like structure and having two bearings made of anti-friction material embedded therein, said bearings having their openings turned towards each other.

8. A mechanism as defined in claim 7, wherein the operating lever has both ends thereof in the form of a fork and has a trunnion about its middle, said trunnion engaging the frame of the mechanism.

9. A mechanism as defined in claim '8, wherein the operating lever consists of two symmetrical cast parts joined together about the middle of the lever by a flat surface, each part having, as an integral part thereof, a trunnion pointing outwardly on the armature side and having a blind hole on the side of the movable contact support, the two parts being assembled so as to form a tenon and mortise point at their meeting surfaces, the length of each trunnion on the armature side being less than half the width of the opening of the armature extensions to permit the trunnions on the armature side to engage the bearings of the armature extensions.

10. A mechanism as defined in claim 9, wherein the movable contact support is in the form of a spider having two trunnions directed in opposite directions for engaging the blind holes of said operating lever.

11. A mechanism as defined in claim 8, wherein said frame includes a base of insulating material having slots therein and further comprising two detachable bearings of plastic material enclosing the middle trunnion of said operating lever and slidably mounted in said slots, whereby the operating lever can be assembled to the base of insulating material by engaging said detachable hearings in the slots of the base.

12. A mechanism as defined in claim 4, wherein the two second levers are joined by a cross-bar having bevelled edges and further comprising an auxiliary switch mounted on the frame of the mechanism, said auxiliary switch being operated by the bevelled edges of said cross-bar.

References Cited UNITED STATES PATENTS 1,908,567 5/1933 Steinmayer "335-490 2,434,070 1/1948 Gross 335- 2,451,323 10/1948 Doane 335 190 3,054,872 9/1962 Clark 335189 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner