US 3277409 A
Description (OCR text may contain errors)
3,2 77,409 con,
Oct. 4, 1966 A. G. FAFFART ELECTROMAGNETIC RELAY ASSEMBLY HAVING A FLAT AND WHOSE ARMATURE ASSEMBLY IS FORMED WITH A DEFORMABLE STEM 4 Sheets-Sheet 1 Filed Jan. 25, 1965 Oct. 4, 1966 A. G. FAFFART 3,277, 9
' ELECTROMAGNETIC .RELAY ASSEMBLY HAVING A FLAT COIL AND WHOSE ARMATURE ASSEMBLY IS FORMED WITH A DEFORMABLE STEM Filed Jan. 25, 1965 4 Sheets-Sheet 2 Oct. 4, 1966 A G. FAFFART 3,277,409
ELECTROMAGNETIC RELAY ASSEMBLY HAVING A FLAT COIL AND WHOSE ARMATURE ASSEMBLY IS FORMED WITH A DEFORMABLE STEM Filed Jan. 25, 1965 v 4 Sheets-Sheet a teal/L c 0 52.
Oct. 4, 1966 A. G. FAFFART 3,277,409
ELECTROMAGNETIC RELAY ASSEMBLY HAVING A FLAT COIL AND WHOSE ARMATURE ASSEMBLY IS roman WITH A DEFORMABLE STEM Filed Jan. 25, 1965 4 Sheets-Sheet 4 United States Patent 3,277,409 ELECTROMAGNETIC RELAY ASSEMBLY HAVING A FLAT COIL AND WHOSE ARMATURE ASSEM- BLY IS FORMED WITH A DEFORMABLE STEM Andr G. Falfart, Nanterre, France, assignor to La Telemecanique Eleetrique, Nanterre, Seine, France, a company of France 7 Filed Jan. 25, 1965, Ser. No. 427,578 Claims priority, application France, Feb. 13, 1964, 963,680; 'Dec. 29, 1964, 273 Claims. (Cl. 335128) This invention has among its objects the provision of an electromagnetic relay assembly which will combine part and preferably all of the following advantageous features:
High compacity, including relatively small size especially as concerns one dimension of the relay assembly, so as to impart to the latter a generally flat configuration and low weight and volume;
Relatively large working capacity, the relay being capable of operating a plurality of switch contacts under comparatively high current conditions, so as to be usable for example in the remote control of powerful machinery;
An advantageously symmetrical construction with relatively few and simple parts making for ruggedness and low cost;
Low angular displacement of the magnetic armature with respect to the magnetic core between the end positions of said armature, thereby reducing wear and increasing response rate;
A self-compensatory feature able to ensure an inherent balancing as between the operation of opposed contacts of the relay irrespective of manufacturing tolerances, an additional cost-reducing and efficiency-improving factor.
A relay assembly according to an important aspect of the invention comprises a generally flat U-shaped core of magnetic material having .a pair of core legs extending in parallel spaced relation in the general plane of the core. Energizable electromagnetic windings are carried on the core legs, end parts of which project beyond the windings. A preferably fiat, elongated armature member of magnetic material has its major dimension extending perpendicular to the common direction of the core legs and has end portions of one side surface thereof engageable with said end parts of the core legs under magnetic attraction when the windings are energized. For movably supporting the armature from the core there is provided a stem extending centrally from the armature in the general plane of the latter and perpendicular to its major dimension, and means are provided connecting the free end of said stem to the core so as to support the armature for limited angular displacement bet-ween a position in engagement with said core leg end portions and a disengaged position, as well as for limited rotation about the centre axis of said stem, to provide the afore-mentioned self-compensatory feature. Contacts are supported outwardly of the core legs for operation by the end parts of the armature on displacement of the latter between its said positions. 7
To permit the said limited angular displacement of the armature between its said positions, the stern may, at its free end, be pivoted with respect to the core for limited rotation about an axis parallel to the major dimension of the armature. Alternatively, the stem may at its free end be rigidly secured to the core, the stern then being constructed so as to possess some deformability in fiexion.
To permit the said limited rotation about the centre axis of the stem, the latter preferably has some deformability in torsion.
The various objects and novel features of the invention will be clearly understood from the ensuing description of 3,277,409 Patented Oct. 4, 1966 exemplary embodiments thereof, with reference to the accompanying drawings wherein:
FIGURE 1 is a perspective view of the main parts of one embodiment of the improved relay assembly including one of the switch contacts operated thereby.
FIGURE 2 is an exploded perspective view illustrating components of the assembly.
FIGURE 3 is :a larger-scale view of the same assembly in elevation and partly in section, with an outer casing wall removed.
FIGURES 4 to 7 are sectional views as seen on the planes designated IVIV, VV, VIVI and VII-VII (FIGURE 3), respectively.
FIGURE 8 is a perspective view illustrating a modified embodiment of the invention; and
FIGURE 9 'is an exploded perspective view illustrating the armature and associated supporting elements, in the embodiment of FIGURE 8.
The relay assembly illustrated in FIGURES 1-7 includes a magnetic core member which is generally U- shaped, being composed of two flat elements 1 and 2 (see FIGURE 2) of generally similar U-like configuration adapted to be assembled in juxtaposed relation. Element2 differs from element 1 in that it has its lower transverse portion press-formed to provide a rounded, vertical groove 2a. When the two core parts 1 and 2 are assembled as presently described, this groove 2a defines with the adjacent'surface of core element 1 a bearing for rotatably receiving the reduced-diameter part 3a of an extractor screw 3.
Two similar electromagnetic windings 5A and 5B are wound on the coil supports or spools 4A and 4B which are internally formed with recesses of rectangular cross section adapted to fit slidably around the respectives legs of both core elements 1 and 2 when the latter are juxtaposed. In operation, it will be understood that both windings 5A and 5B are preferably connected up in series. The connecting wire, not shown, may be provided by a conductor within the relay assembly itself or by an external conductor, as desired.
The legs of the respective core elements 1 and 2 have holes 611 and 6]) formed in their upper and lower ends, holes 6a being smooth and holes 6b being screw-tapped, and screws 7 project through the holes 6a and are threaded into the holes 611 to hold the elements 1 and 2 assembled. The screws 7 also serve to clamp about the lower and upper ends of the core assembly 1-2, a lower'cross-memher 8 and an upper cross-member 9, both members 8 and 9 being made of insulating molded material and being generally rectangular and similar in shape. The crossmembers -8 and 9 are visible in FIGURES 3 to 7, and it will be seen e.g. from FIGURE 6 that the lower crossmember 8 has a slot in its bottom edge which fits around the stem of the lower screws 7 between the head of the screw and core element 1; and similarly upper cross-memher 9 has 'a slot in its upper edge which fits around the stem of upper screw 7 between its head and element 1. The cross-members 8 and 9 serve to support the contact elements of the relay assembly as later described.
Thin strips 10 of non-magnetic material are inserted around the upper pair of screws 7 in contact with the outer surfaces of the legs of the core element 1. These nonmagnetic insert strips 10 serve, as will later become clear, as spacers to provide a definite airy'gap between the core and armature in the attracted position of the armature, and prevent the armature clinging under remanent magnetism.
The lower cross-member 8 has upstanding walls 11a (FIGURE 3) projecting upward from it and defining between them a cavity 11 in which are received the pair of electromagnet windings 5A and 5B. In the opposite ends of this cavity 11 at the bottom of it, are formed aligned semi-cylindrical sockets or recesses 12. These sockets receive the end trunnions 13 of the pivoted armature-carrier generally designated 15 (FIGURE 2), nowto be described. i
The armature-carrier 15 is a molding of insulating material, in the general shape of an anchor or a double-T, with a longer upper cross-member 17 and a shorter lower cross-member 14, interconnected by the central stem 18. The aforementioned trunnions 13 are provided at the ends of lower cross-member 14. Within the upper crossmember 17 is embedded the armature member proper, which is an elongated rectangular strip of ferromagnetic material as can be seen from FIGURES 3 and 4. The armature-carrier 15 is, preferably, molded directly around the armature 16 during the process of making said carrier, and the armature 16 serves, in addition to its main magnetic function, as an internal reinforcement for the insulating molded material of the upper cross-member 17. The upper and lower cross-bars 17 and 14 of the armature-carrier 15 are interconnected by the central vertical stem part 18, integral with them, and here shown with a channel shaped section. The cross sectional dimensions of the stem 18 are predetermined so that the stem will have a certain amount of torsional deformability for reasons to appear later.
As may be seen from FIGURES 4 and 6 the material of the upper cross-bar 17 is removed or omitted from two spaced portions thereof registering with the polar legs of the core element 1 so as to leave corresponding portions of the side surface of the armature 16 bare for attraction towards and engagement with said polar legs of the core. The material of the cross-bar 17 located bet-ween said bare portions of the armature defines an insulating strip 19 with which are integrally formed two spaced projecting bosses 20. The bosses 20 serve as centering supports for the pair of compression coil springs 21 acting to bias the armature assembly towards its idle position out of engagement with the core as will presently appear. The springs 21 have their one ends engaging the armaturecarrier strip 19 and their other ends engaging a. metallic spacer strip member 22 which serves to space the winding supports 4A and 4B and block said winding supports within the cavity 11. The enlarged upper part 22a of spacer strip 22 engages lugs 23 projecting from the upper ends of the winding supports 4A, 4B.
When the trunnions 13 of the lower crossbar 14 of the armature assembly 15 are received in the sockets 12, it will be noted from FIGURES 6 and 7 that the centre axis of said trunnions lies substantially in the same plane as the outer side surface of core element 1, and also that the side surface of the armature 16 directed towards said core element defines a plane which extends through said centre axis of the trunnions. When windings 5A and 5B are deenergized, the armature-carrier 15 and armature 16 assume the position shown in said FIGURES 6 and 7. With the windings energized, the armature 16 is attracted so that the armature assembly rocks about trunnions 13 and the strip 16 is applied flat against the adjacent side surface of core element 1; the metallic insert strips 10 prevent the armature from sticking to the core due to remanent magnetism.
To connect the free ends of the windings 5A and 5B with an external energizing circuit, there are provided the two similar conductor strips 25. Each strip 25 has a narrow intermediate part extending through a groove 26 formed in a wall of the inner recess of the related winding supports 4A, 4B, which groove is defined between spaced ribs 28. An insulating spacer strip 27 is inserted after having its side edges bent back at right angles from the flat condition shown in FIGURE 2, into the space between the adjacent surface of the core element 2 and the free edge surfaces of the ribs'28, in the manner shown in FIGURE 6, so as to isolate the conductor strip 25 from the core.
- external testing circuit or the like.
Conductor member 25 has a spade shaped lower end part 29 which has its side edge portions bent back at right angles from the flat condition shown in FIGURE 2 and protrudes from the lower end of the relay assembly to provide a pluggable connector for cooperation with a related plug in an appropriate plug-in base, not shown. The upper extremity 30 of the conductor 25 is bent to provide a resilient contact element located some distance within a vertical passage 32 formed through the upper cross-member 9 and the top wall of the casing 31 surrounding the assembly. Connection can thus be made from connector member 25 with a plug, not shown, insertable through said passage 32 and forming part of an A centrally perforate plug 33 of suitable insulating resilient material is forcefitted into said passage around the connector member 25 and serves to stiffen and centre said member and also to prevent the entry of foreign materials into the interior of the relay structure.
In the illustrated embodiment, the relay assembly operates a system of reversing switch contacts, which includes four contact pairs, two on each side of the assembly. The upper crossbar 17 of the armature-carrier 15, at each of its ends, has two spaced lugs 34 and 35 projecting from it in the rearward direction (i.e. towards the core), each of said lugs serving to operate a related one of the contact pairs on that side of the structure.
Each of the four contact pairs constitutes an elongated structure generally parallel to the legs of the U-shaped core and supported between the lower and upper crossmembers 8 and 9.
FIGURE 1 and FIGURE 2 each show only one of the four sets of reversing contact switches referred to above, that one which is operated by the lug 34 on the near side of the armature carrier. It will be understood that all four reverser contact switches may be generally identical.
The construction of a reverser switch is best apparent from FIGURE 5, in which it is seen that the switch includes a central conductor strip 36 having a lower end 36a protruding below the relay structure to provide a pluggable connector, and an upper end 36b accessible (e.g. for testing purposes) through one of the access passages 32 at the top of the assembly. Central switch conductor 36 has opposed contacts 37 on its opposite sides. The reverser switch further includes the pair of spring strips 39 provided with contacts 38 cooperating with the respective contacts 37 on the opposite sides of the central strip 36. The lower ends of the spring strips 39 are rigidly supported by being crimped between inturned plugs 41 provided near the base of the conductive side strips 42. Each side strip 42 in addition to the lugs 41 serving to crimp the spring strips 39, includes a protruding lower end part 42a which provides a pluggable connector similar to the connector 29, and an upper extremity 42b providing a testing connector accessible through an upper passage 32. The side strips 42 are bent to the configuration clearly apparent from FIGURE 5 for their firm and rigid support in the relay structure, and act in turn firmly to support the spring contact strips 39. Compression coil springs 40 interposed between the outer sides of the spring strips 39 and the inner sides of side strips 42 bias the spring strips 39 into contact engagement with the central contact strip 36. In the operative condition of the system, electric current flows from each pluggable contactor 42a to the contact 38 of the related spring strip 39, both by way of the crimped connection 41 and strip 39, and by way of the side strip 42 and spring 40.
A key insert 43 made of insulating material extends through aligned holes 45 formed in the three protruding contactors 36a and 42a in the base of the relay casing to maintain said contactors in properly spaced and isolated relation.
The upper ends 4211 of the side strips 42 are angled to impart flexional resiliency thereto. A frusto-pyramidal plug member 44 made of resilient insulating material is perforated to receive an upper part 36b of the central contact strip 36 therethrough and serves to position and centre resiliently the upper portion 36b of said central strip as well as the upper portions 42b of the side strips 42 which resiliently engage opposite sides of said plug. The resilient'plug 44 (like the plug 33 mentioned earlier) serves also to seal the passages in the upper part of the structure through which said strips project. The said upper strip parts 36b and 42b are thus accessible for contact with a conductive plug 46 as indicated in dotdash lines in FIGURE 5 through the related passage 32, efiicient contact being ensured due to the resilient deformation both of said contact parts 36b, 42b per se, and of the plug 44. It will be understood that the upper contacts such as 361) and 42b accessible through the upper passages 32 serve primarily for connection of the respective switch elements to suitable testing circuits during checking and testing procedures.
As indicated earlier, each reverser switch similar to the one just described in detail is operated between its two reverse conditions by an actuator lug 34 or 35, of the upper crossbar 17 of the movable armature assembly. Thus, FIGURE 5 shows one of the reverser switches operated, by a lug 35, to that one of its conditions in which the left-hand movable contact 38 is disengaging the associated fixed contact 37 and the right-hand movable contact 38 is engaging its associated fixed contact 37. For this purpose, each of the actuating lugs, 34 and 35, is formed with opposite shoulders 47 and 48 at its base, which engage the inner surfaces of the respectively related spring strips 39, the lug 35 (or 34) being interposed between said spring strips and projecting through a rectangular slot 49 formed in the central strip 36. The engagement of the lugs in the slots 49 simultaneously contributes to guidance of the armature assembly -16 during its movements. When the armature assembly 15 is rocked between its end positions about the trunnions 13, the lug 35 (or 34) acts alternatively with its shoulder 47 or 48 upon one or the other of the spring strips 39 to operate the contact switch to a related one of its two reverse conditions.
The inner two actuator lugs 34 are similar to the outer actuator lugs 35 except that they each include an upwardly-outwardly directed nose extension 50 adapted to engage the associated resilient frusto-pyramidal plug 44 for resiliently limiting the movement of the armature assembly towards its unattracted or idle position as shown in FIGURE 5. As shown in FIGURE 2, the crossbar 17 of the armature assembly may have additional protrusions 51 serving to extend the electrical leakage path between the respective reverser contact switches. An upstanding extension 52 of said upper crossbar 17 is visible through an upper passage 53 (see FIGURE 3) from the top of the relay structure, thereby to indicate whether the armature is in its attracted or unattracted position.
The central extractor screw 3 extends through an opening formed in the upper cross-member 9 and through the recess 2a in the lower part of the core 1-2, as earlier explained, and its protruding threaded end part is engageable with a threaded hole in the socketted base member, not shown, in order to guide the plugs 29, 36a, 42a, during insertion and withdrawal thereof into and out of the plug sockets in said base and thereby prevent distortion of said plugs in the usual manner.
The operation of the relay assembly need not be described in detail since it will be self-evident in the light of the foregoing disclosure. Energization and deenergization of the windings 5A, 5B cause the armature assembly 15 to rock about its trunnions 13 between its end positions, thereby operating the reverser switches in the manner described. It will be noted that owing to the substantial length of the connecting stem part 18, the angular movement of the armature assembly required to bring about the requisite linear displacement stroke for reliably operating the reverser switches, is very small, so that the wear of said trunnions in their bearings is negligibly low even after an extremely large number of relay operating cycles. Owing to the torsional resiliency of the stem 18, square and accurate engagement of both ends of the armature 16 with the respective legs of the U-shaped core 12 will be effected even in case of appreciable misalignment between the two sides of the relay assembly as may be due to manufacturing tolerances and/ or disturbing conditions resulting from prolonged use.
The modified embodiment shown in FIGURES 8 and9 differs from the embodiment above described only in the construction of the armature assembly, and will hence not be described in complete detail. In this case the armature assembly is built up from a stack of four contoured strips, the strips 68, 69 and 70 being of ferromagnetic material while strip 71, interposed between 69 and 70, is made of spring steel. Strip 68 has laterally projecting lugs 63a arranged to receive boots 80 of insulating material fitted thereover, for operating the reverser switch contact elements in a manner generally similar to that earlier described in regard to the lugs 34 and 35. The spring steel strip 71 is in the form of a double-T and serves a supporting functionbroadly equivalent to that of the anchor-shaped member 15 of the first embodiment. Here however, the lower crossbar 71a of said supporting member 71 rather than being pivotally mounted, is rigidly secured by means of rivets 75 and an auxiliary strip 76 of the central part of a bridge member 77 having side lugs secured with screws 78 to the core 12. At their upper part all four strips 68, 69, 71 and 70 are assembled in juxtaposed relation by means of rivets 72 extending through aligned holes in the strips. The vertical stem portion 71b of carrier member 71 is capable not only of torsional deformation as the stem 18 of the first embodi: ment, but also of flexional deformation. It is the flexional deformation of the stern 71b in a direction normal to the general plane of the strip 71 which in this embodiment permits the requisite displacement of the armature assembly between its end positions. During its bending deformations, the stem 71b is supported by the adjacent extensions 69a and 70a of the strip elements 69 and 70 positioned to opposite sides from the carrier strip 71. The lower ends of extensions 69a and 70a are bent outward as at 6% and 70b to provide eificient guiding action for the stem 71b without damage thereto. The auxiliary strip 76 for a similar purpose has an outbent upper extension lug 76a. The upward extension 69c of the cruciform strip element 69 serves to provide an indicator of the attracted or unattracted condition of the armature assembly, and can also serve to actuate the armature assembly manually between its positions for testing purposes.
The embodiment of the invention shown in FIGURES 8 and 9 works essentially in the same way as the first embodiment except for the difference indicated above, and it exhibits broadly the same advantages as those indicated with respect to the first embodiment. Various other modifications and variants may be conceived without departing from the scope of the invention.
What I claim is:
1. A relay assembly comprising a generally flat core of magnetic material having a pair of core legs extending in parallel spaced relation in the general plane of the core; energizable electromagnetic windings carried by said core legs; an armature assembly in the general form of a double T including an upper cross arm, a stern projecting centrally from said upper cross arm perpendicularly thereto and a lower cross arm at the free end of said stem; a magnetic armature member substantially coextensive and rigidly movable with said upper cross arm; means connecting said lower cross arm with said core so as to mount the armature assembly for limited displacement between a position in which end portions of a side surface of said armature member laterally engage with end parts of the respective core legs under magnetic attraction when the windings are energized, and a disengaged position in which said armature member is spaced from said core legs; relay contacts supported at lateral sides of said relay assembly outward of the respective core legs; and contact actuating means supported from said upper cross leg of the armature assembly near respective ends thereof for actuating said contacts on displacement of the armature assembly between its said positions, said stern having torsional deformability for equalizing the actions of said contact actuating means upon the respective contacts.
2. The relay assembly defined in claim 1, wherein said stem is substantially undeformable in flexion, and said connecting means comprise means pivoting said lower cross arm to said core about an axis parallel to said cross arms and armature member.
3. The relay assembly defined in claim 1, wherein said stem has substantial flexional deformability and said connecting means comprise means rigidly securing said lower cross arm to said core. I
4. The relay assembly defined in claim 1, including upper and lower cross members of insulating material secured across upper and lower end parts of said core, and said contacts are in the form of contact strip assemblies having major dimensions parallel to the core legs and having spaced parts supported from said upper and lower cross members.
5. The relay assembly defined in claim 4, wherein each contact strip assembly includes a stationary central conductive strip having spaced parts secured to said cross members, and two flexibly movable spring strips on opposite sides of the central strip and cooperating therewith, and said contact actuating means are interposed between both said spring strips so as to actuate one or the other into contact engagement with the central strip depending on the direction of displacement of said armature between its said positions.
6. The relay assembly defined in claim 5, wherein each of said contact strips has a conductive extension at its lower end projecting beyond said lower cross member for plug-in connection with external connector means, and an upper contact portion accessible from above the top of the assembly for connection with other external connector means for testing purposes.
7. The relay assembly defined in claim 6, wherein said core comprises a pair of flat U-shaped elements having means for assembling them in flat juxtaposed relation, the transverse base portions of said U-shaped elements defining therebetween a bearing recess, and an extractor screw having an intermediate portion rotat-ably received in said bearing recess and having a threaded end part protruding beyond the lower end of the relay assembly for engagement with a threaded hole in a base formed with plug sockets for plugg-able engagement of said conductive extensions of the contact strips.
8. The relay assembly defined in claim 1, including a spring acting between said armature assembly and said core to urge the armature assembly to one of its. said positions.
9. The relay assembly defined in claim 1, wherein said upper cross arm is molded from insulating material around said armature member, which latter comprises a strip of ferro-magnetic material.
10. The relay assembly defined in claim 1, wherein said armature assembly comprises a plurality 'of stacked strips.
References Cited by the Examiner UNITED STATES PATENTS 2,445,401 7/1948 Langer 20'087 2,824,189 2/1958 Zimmer 200l04 2,946,873 7/1960 Distin 200-87 BERNARD A. GILHEANY, Primary Examiner.
J. J. BAKER, Assistant Examiner.