US2993103A - Electromagnetic relay - Google Patents

Description

July 18, 1961 J. s. ZIMMER ELECTROMAGNETIC RELAY 3 SheetsSheet 1 Filed Jan. 26, 1960 INVENTOR JOHN s. ZIMMER, MW? 0mm ATTORNEY.

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1961 J- 5. ZIMMER 2,993,103

ELECTROMAGNETIC RELAY Filed Jan. 26, 1960 s Sheets-Sheet 2 NORMALLY OPEN TERMINAL 2 -24 SWITCH N0-2 I I NORMA NORMALLY I CLOS CLOSED Z TERM|NAL4 TERMINAL I0 NORMALLY I CLOSED NORMALLY TERMINAL 2 OPEN 2 SWITCH N0 4 TERMINALS l6 IO lo u I i I flWf i I i SWITCH No.2v- 5 NORMALLY CLOSED l6 NORMALLY TERMINAL3 c SED NORMALLY/ 7 TER CLOSED g4 TERMINALS |o SWITCH No.6 I 24/ N MALLY OPEN I NORMA Y OPEN RMINALG TER AL s V INVENTORZ JOHN s. ZIMMER,

W3 ATTORNEY.

July 18, 1961 J. s. ZIMMER ELECTROMAGNETIC RELAY Filed Jan. 26, 1960 3 Sheets-Sheet 3 SWITCHING swncnms TERMINAL l TERMINAL 2 con. TERMINAL@ NORMALLY CLOSED TERMINAL \fisia'iwxfiaaaai NORMALLY OPEN TERMINAL INVENTOR I JOHN S. ZIMMER nited States Patent O 7 2,993,103 ELECTROMAGNETIC RELAY John S. Zrrnmer, Waynesboro, Va., assignor to General Electric Company, a corporation of New York Filed Jan. 26, 1960, Ser. No. 4,703 4 Claims. (Cl. 200-87) The invention relates to an electromagnetic relay, and particularly to a compact assembly comprising a plurality of individual electromagnetic switches.

An object of the invention is to provide an improved relay assembly of a plurality of electromagnetic switches.

Another object of the invention is to provide an improved and novel relay assembly comprising a plurality of electromagnetic switches, the assembly being relatively small and compact.

Another object of the invention is to provide an improved relay assembly comprising a plurality of individual electromagnetic switches, all of the individual switches being operated by a single common winding.

The invention is an improwement and utilization of the invention described and disclosed in the copending patent application filed in the name of I S. Zimmer on January 21, 1959, Serial No. 788,197. The invention contemplates the use of a switch such as described and shown in this copending application, but is not to be considered limited to such a switch. As will be apparent to persons skilled in the art, the invention can be used with a number of different embodiments. Briefly, in accordance with the invention, a number of basic or individual switch units or switches are assembled together with an insulating strip positioned between each of the switches. Brackets, preferably having an L-shaped configuration, are fastened to each of the ends of the switch cores for two purposes. The first is to provide a convenient terminal point for connecting certain of the switch elements to external circuitry. The second is to provide a relatively low reluctance path for the magnetic circuits of the individual switches. A single coil or winding is positioned around all of the switch elements. The coil, the switches, and the L-shaped brackets are surrounded by a suitable insulating material. The insulating material, in turn, is surrounded by a suitable cover of magnetic material which is separated from the L- shaped brackets by an amount equal to the thickness of the insulating material. Thus, the paths for the magnetic circuits of each switch comprise a low reluctance magnetic material and a small air gap equal to the thickness of the insulation. This provides an extremely desirable arrangement inasmuch as the low reluctance magnetic paths insure good pickup operation when the relay coil is energized, and the air gap provides or insures satisfactory dropout of the relay when the coil is rte-energized.

The invention will be better understood from the fol lowing description taken in connection with the accompanying drawing and its scope will be pointed out in the claims. In the drawing:

FIGURE '1 shows a longitudinal cross-sectional view of one embodiment of a relay assembly in accordance with the invention, the view of FIGURE 1 being taken along the lines 1- 1 of FIGURES 2 and 3 and further showing a portion broken away to illustrate one example of an individual switch construction which may be used in the assembly;

FIGURE 2 shows a transverse cross-sectional view of the relay assembly taken along the lines 2--2 of FIG- URE l and also shows a portion broken away for illustrating one example of an individual switch construction which may be used in the assembly;

FIGURE 3 shows an elevation or side view of the as- Patented July 18, 1961 sembly of FIGURE 1 as viewed from the right of FIG URE l; and

FIGURE 4 shows a transverse cross-sectional view of another embodiment of the relay assembly.

In the figures, the same reference numerals are used to refer to the same elements. In FIGURES 1, 2, and 3, a relay assembly comprising six individual, single pole, double throw switches is shown. Again, it is emphasized that the invention need not be limited to an arrangement comprising six individual switches as shown in FIG- URES l, 2, and 3 or need not be limited to an arrangement comprising three individual switches as shown in FIGURE 4. The arrangements shown are examples only, and in accordance with the spirit and scope of the invention, may be extended to any number (including two or more) of switches assembled in accordance with the invention.

With reference to FIGURES 1, 2, and 3, there is shown a relay assembly comprising six individual switches arranged as shown. As will be explained in greater detail, each of the switches may be housed in a cylindrical metallic tube 10 of nonmagnetic material such as nonmagnetic stainless steel. The cylindrical tubes 10, each containing its respective switch, are arranged to form three rows of two tubes each, with the tubes coextensive, and with their longitudinal axes parallel. Each of the cylindrical tubes 10 is electrically insulated from the adjacent cylindrical tubes 10 by means of insulating strips 12 formed of some electrically insulated material such as a plastic. The insulating strips 12 extend beyond the cylindrical tubes 10 as shown in FIGURE 1. As will also be explained hereinafter, each of the individual switches may be a hermetically sealed unit. Projecting from the ends of the individual switches are core extensions 14, 16, which :form a part of the switch magnetic circuit. These core extensions 14, 16 are generally cylindrically shaped and formed of a magnetic material. Surrounding and providing support for the individual switches and the insulating strips 12 is a spool-shaped coil form 18 made of an electrically insulating material such as plastic. The coil form 18 has the configuration or shape as to surround the individual switches as closely as possible and hold them in the desired position. A coil 20 is wound on the coil form 18 and its ends are brought out on coil terminals 22. As shown in FIGURE 1, the coil form 18 and coil 20 leave a portion of the core extensions 14, 16, uncovered to provide clearance for L-shaped brackets 24. Each of the outer ends of the core extensions 14, 16 have a portion which is ground or machined to provide a fiat surface on which one L-shaped bracket 24 is fastened. The fiat surface portion of the core extensions 14, '16 are oriented so that the L-shaped brackets 24 provide an outline or framework on which an assembly cover 26 may be mounted. The L-shaped brackets 24 are made of a magnetic material, and may be fastened to their respective core extensions 14, 16 by any suitable means, such as welding. Surrounding the L-shaped brackets and the coil form 18 and coil 20 is the assembly cover 26 which is made of magnetic material and which preferably has an insulating strip 28 located around its entire inner surface. The insulating strip 28 may be made of any suitable electrical insulating material such as a plastic film or coating. The assembly cover 26 is positioned over or around the coil form 18, the coil 20, and the ends of the L-shaped brackets 24. The cover 26 is preferably dimensioned to provide a fairly snug fit and at the same time not scar or break the insulating strip 28.

An individual terminal is connected to each of the L-shaped brackets 24 to each of the cylindrical tubes 10 to provide electrical connections to the switch elements as will be explained. With the arrangement just described assembled within the assembly cover 26, a suitable thermally setting potting compound of electrically insulating material such as epoxy filled resin may be poured into the ends of the entire assembly to firmly support and insulate the various connections and elements in the proper manner.

Before the operation of the novel and improved relay assembly is discussed, the construction of one of the individual switches will be explained. In FIGURE 1, a longitudinal cross-sectional view of switch No. 3 is. shown, this view of switch No. 3 being taken along the dashed line in FIGURE 2 which passes through the center of switch No. 3. A transverse cross-sectional view of switch No. 4 is shown in FIGURE 2, this cross-sectional view being taken along the dashed line in FIGURE 1 which passes through the center of switch No. 3. As already mentioned, each of the individual switches comprises cylindrical core extensions 14, 16 formed of a magnetic material. The core extensions 14, 16 are respective extensions of first and second core elements 40, 42 which are preferably, but not necessarily, integral and formed from the same material as their respective core extensions 14, 16. The core elements 40, 42, which are also cylindrical, are axially aligned and are separated by an air gap 44 which, as shown in FIGURE 1, may be generally described as X-shaped and which is formed by the free or inner end surfaces of the core elements 40, 42. An armature 46 is formed from the material of the core elements 40, 42, and has a shape which corresponds to or substantially fits in a portion of the air gap 44. This process is fully discussed in the copending application mentioned above. The armature 46 is fastened to a spring 48 which in turn is fastened to a flat portion of the first core element 40 by any suitable means such as welding. The spring 48 is preferably made of a fiat elongated strip of resilient material such as an alloy of silver, nickel, and magnesium, and is bent or shaped so that it rests substantially in the position shown in FIGURE 1. The spring 48 carries a spring contact 50 preferably formed of a high conductivity metal that is silver plated, the spring carried contact 50 being on the opposite side of the spring 48 from the armature 46. The spring carried contact 50 normally (i.e., when the switch is released) engages a contact bar 52 which is also preferably formed of a high conductivity metal that is silver plated. The contact bar 52 has an extension which is bent to provide a backstop 54 for the free end 56 of the spring 48. The backstop 54 helps to reduce bouncing or oscillation of the spring 48 when the switch is released or dropped out to its normal position. The free end 56 of the spring 48 is positioned in the vicinity of the second core element 42 but is normally separated therefrom. When the switch is energized (i.e., pulled up from its normal position), the free end 56 of the spring 48 engages a contact 58 which is preferably formed of a high conductivity metal that is silver plated, and which is fastened to a flat portion of the second core element 42. Since the free end 56 of the spring 48 provides an electrical circuit to the cont-act 58 on the second core element 42, and since the free end 56 may flex or whip when the switch is released or dropped out so that the free end 56 engages the backstop 54 before the spring carried contact 50 engages the contact bar 52, the entire spring 48 or at least the free end 56 portion may preferably be plated or alloyed with a suitable high conductivity metal such as silver,

The contact bar 52 and its backstop 54 are supported by an inner tube 60. The inner tube 60 is formed from a suitable piece of cylindrical, nonmagnetic material such as stainless steel so that it has two cylindrical end supports 62, 64 which are joined by two longitudinally running strips 66. On the lower side and between the two strips 66, a semicylindrical support 68 is provided. This support 68 carries the contact bar 52 and its backstop 54. The contact bar 52 is preferably fastened to the support 2,998,103 j r c f 68 before the switch is assembled. The inner tube 60 is supported in an electrically insulated relation between the core extensions .14, 16 of the respective core elements 40, 42 by electrically insulating cylindrical heads 7 0 which surround the core extensions 14, 16 and bear against the shoulders formed by the core elements 40, 42. The cylindrical beads 70 may be rigidly fastened to the core extensions 14, 16 by any suitable means. Glass beads are preferred as they can be fused to the core extensions 14, 16 to provide a hermetic seal. When in position, the inner tube 60 is outside the core elements 40, 42, part of the core extensions 14, 16 and the cylindrical beads '70. The inner tube 60 is supported by and rigidly fastened to the beads 70 at its respective end supports 62, 64. The metallic cylindrical tube 10 of nonmagnetic material is placed around the inner tube 60 to completely enclose and surround the switch elements. The cylindrical tube 10 may be fastened to the inner tube 60 around the entire circumference of the inner tube 60 at the end supports 62, 64 under such conditions as to hermetically seal the moving switch parts under the most desirable conditions, such as in an atmosphere of dry inert gas. If desired, insulating spacers or washers 72 may be slipped over the core extensions 14, 16 to bear against the outer ends of the end supports 62, 64 and the cylindrical tube 10. -As previously mentioned, each of the individual switches such as the one just described has its cylindrical tube 10 electrically insulated from other metallic elements by means of the insulating strips 12. Also as mentioned, a potting compound is poured into the assembled switch assembly to provide additional insulation and hold the various switches and component parts in their desired position.

When the coil 20 is deenergized and the individual switches are in their normal or released position, the switch elements have the position shown for switch No. 3 in FIGURE 1. An electrically closed circuit is provided from the switching terminal on an L-shaped bracket 24 (labeled in FIGURE 3) through the L-shaped bracket 24, the core extension 14, the first core element 40, the spring 48, the spring contact 50, the contact bar 52, the support 68, the inner tube 60, the cylindrical tube 10, and finally to the normally closed terminal (labeled in FIGURE 2) which is fastened to the cylindrical tube 10. An electrically open circuit also exists between the switching terminal and the normally open terminal on an L-shaped bracket 24 (labeled in FIG- URE 2) since the second core element 42 and its core extension 16 are electrically insulated from the remainder of the switch elements. When the relay coil 20 is energized, however, the armature 46 is drawn up in the air gap 44 towards the core elements 40, 42 until the free end 56 of the spring 48 engages the contact 58. The armature 46 continues to be drawn up into the air gap 44 until the faces of the armature 46 contact the corresponding end surfaces of the core elements 40, 42. This overtravel of the armature 46 provides a desirable wiping of the free end 56 of the spring 48 across the contact 58. An electrically closed circuit is thus provided from the switching terminal on an L-shaped bracket 24 (labeled in FIG- URE 3) through the L-shaped bracket 24, the core extension 14, the first core element 40, the spring 48, the free end 56, the contact 58, the second core element 42, the core extension 16, and finally to the normally open terminal on an L-shaped bracket 24 (labeled in FIGURE 2). An electrically open circuit also exists between the switching terminal and the normally closed terminal (labeled in FIGURE 2) which is fastened to the cylindrical tube 10 because the spring contact 50 is disengaged from the contact bar 52. With the armature 46 of each individual switch contacting the core elements 40, 42, a good magnetic path is provided between each of the core elements 40, 42 and the energizing coil 20. This path includes the asembly cover 26, the L-shaped brackets 24 associated with the switching terminals, the core extensions 14, the first core elements 40, the armatures 46, the second core elements 42, the core extension 16, the L- shaped brackets 24 associated with the normally open terminals, and finally back to the assembly cover 26. However, a gap of nonmagnetic material remains between the assembly cover 26 and each of the L-shaped brackets 24 as a result of the insulating strip 28 on the interior surface of the assembly cover 26. This insures that each of the individual switches will drop out readily when the energizing coil 20 is deenergized.

FIGURE '4 shows an arrangement using three individual switches instead of the six described above in connection with FIGURES 1, 2, and 3. In FIGURE 4, certain of the parts have the same reference numerals as their corresponding parts in FIGURES l, 2, and 3. In the arrangement shown in FIGURE 4, the three switches are coextensively positioned in a triangle, and the coil, the coil form, and the assembly cover are shaped accordingly. The view of FIGURE 4 shows the normally closed terminals connected to the cylindrical tube at the outer surface thereof to provide good separation between these terminals. 'I hese normally closed terminals may be positioned elsewhere if desired. The arrangement shown in FIGURE 4 has a magnetic circuit similar to the one shown and described in connection with FIG- URES l, 2, and 3.

While the invention has been described in two specific embodiments, namely a relay assembly having three individual switches and a relay assembly having six individual switches, it will be appreciated by persons skilled in the art that different numbers of switches may be used in an assembly in accordance with the invention. For example, it will be apparent to persons skilled in the ant that an assembly comprising seven individual switches arranged with one central switch surrounded by six switches provides a comp-act and efficient arrangement. And while the invention has been described with reference to particular embodiments, it is to be understood that modifications may be made by persons skilled in the art without departing from the spirit of the invention or from the scope of the claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A relay assembly comprising a plurality of individual switches, each of said individual switches comprising a core having first and second core elements of magnetic material, said core elements being separated by a gap, a fiat elongated spring having one end fastened to said first core element and the other end positioned in the vicinity of but normally separated from said second core element, said" spring comprising an armature of magnetic material positioned in the vicinity of said gap and normally spaced from said core elements, and a contact positioned adjacent said spring, said spring being biased so that said spring normally engages said contact, said individual switches being positioned together but electrically insulated from each other, an energizing coil surrounding said individual switches, an assembly cover formed of magnetic material surrounding said energizing coil but electrically insulated therefrom, and a bracket formed of a magnetic material fastened to each of said core elements for providing a magnetic circuit having a nonmagnetic gap between each of said individual switches and said assembly cover.

2. A relay assembly comprising a plurality of individual switches, each of said individual switches comprising within a non-magentic tube a core having first and second core elements of magnetic material, said core elements being separated by a gap, a fiat elongated spring having one end fastened to said first core element and the other end positioned in the vicinity ofbut normally separated from said second core element, said spring comprising an armature of magnetic material positioned in the vicinity of said gap and normally spaced from said core elements, and a contact positioned adjacent said spring, said spring being biased so that said spring normally engages said contact, said individual switches being positioned together but with said tubes being separated from each other by insulation, an energizing coil surrounding said positionedtogether switches, an assembly cover formed of magnetic material and having an insulating strip on at least a portion of the inner surface thereof, and L-shaped brackets formed of a magnetic material fastened to each of said core elements for providing a magnetic circuit between each of said individual switches and said assembly cover, said mangeticcircuit including said insulating strip as a part thereof.

3. A relay assembly comprising a plurality of individual switches, each of said individual switches comprising a core having first and second core elements of magnetic material, said core elements being separated by a gap, an elongated spring having one end fastened to said first core element and the other end positioned in the vicinty of but normally separated from said second core element, an armature of magnetic material fastened to said spring, at least a portion of said armature being positioned in said gap and spaced from said core elements, a contact bar positioned adjacent said spring, said spring being biased so that said spring normally engages said contact bar, and a tube-like element formed of non-magnetic material positioned around said core elements, said spring, said armature, and said contact bar whereby said individual switch provides a closed circuit between said first core element and said contact bar and an open circuit between said first core element and said second core element in response to an energizing coil being deenergized and whereby said spring is drawn toward said second core element to provide a closed circuit between said first core element and said second core element and an open circuit between said first core element and said contact bar in repsonse to an energizing coil being energized, each of said individual switches being grouped together in a compact arrangement but having their respective tube-like elements electrically insulated from one another by suitable insulating means, an energizing coil positioned around said group of switches, an assembly cover formed of magnetic material and having electrical insulation on at least a portion of its inner surface positioned around said energizing coil, and an L-shaped bracket formed of magnetic material fastened to each of said core elements with one of the surfaces of said L-shaped bracket being positioned against the inner surface of said insulation on said assembly cover, for providing support for said group of switches and for providing a magnetic path between each of said individual switches and said assembly cover, said magnetic path including said insulation on said assembly cover as a part thereof.

4. A relay assembly comprising a plurality of individual switches, each of said individual switches comprising a core having first and second core elements of magnetic material, said core elements being separated by a gap, an elongated spring having one end fastened to said first core element and the other end positioned in the vicinity of but normally separated from said second core element, an armature of magnetic material fastened to said spring, at least a portion of said armature being positioned in said gap and spaced from said core elements, a contact bar positioned adjacent said spring, said spring being biased so that said spring normally engages said contact bar, and a cylindrical tube formed of nonmagnetic material positioned around said core elements, said spring, said armature, and said contact bar, said cylindrical tube being electrically connected to said contact bar whereby said individual switch provides a closed electrical circuit between said first core element and said contact bar and an open electrical circuit between said first core element and said second core element in response to an energizing coil being deenergized and whereby said spring is drawn toward said second core element to provide a closed electrical circuit between said first core element and said second core element and an open electrical circuit between said first core element and said contact bar in response to an energizing coil being energ-ized, each of said individual switches being coextensively grouped together in a compact arrangement but having their respective cylindrical tubes electrically insulated from each other by suitable insulating means, an energizing coi-l positioned around said grouped switches, an assembly cover that is formed of magnetic material and that has insulation on its inner surface positioned around said energizing coil, and an L-shaped bracket formed of magnetic material fastened to each of said core elements with a free flat surface of said L- shaped bracket being positioned against the inner surface of said assembly cover insulation for prOViding support for said individual switches, each of said individual switches having a magnetic path including said L-shaped References Cited in the file of this patent UNITED STATES PATENTS 2,037,535 Rankin Apr. 14, 1936 2,630,506 Buch Mar. 3, 1953 2,821,597 Germanton et al. Jan. 28, 1958 2,889,424 Glore et al. June 2, 1959 2,892,052 Ducat-i June 23, 1959 2,902,558 Peek Sept. 1, 1959 2,938,982 Brown et al. May 31, 1960

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