Thermostat

Abstract: A thermostat (A) including a pair of switches with contacts (30,32,38,40) connected to at least three terminal members (D,E,F,G) having connector terminals (10,12,14,16) aligned along a common axis.

Description: The present invention relates to a thermostat of the type having a pair of switches. A thermostat for two temperature control includes a pair of switches, each having a pair of contacts. Arranging the connector terminals of such a device in line for use with a multifit connector is difficult to accomplish without exceeding the desired envelope in which all of the components are mounted. It would be desirable to have a thermostat of the type described wherein the terminal members are fitted within a very confined space. In FR-B-2 251 090 there is described a thermostat according to the preamble of claim 1. More specifically, this type of thermostat has a housing enclosing a pair of switches, with each switch having a pair of contacts including a fixed contact and a movable contact. Terminal members are connected with each contact and project externally of the housing for connecting the thermostat in a circuit. In this arrangement of FR-B-2 251 090 the external terminals extend outwardly in opposite directions so that they cannot be simultaneously plugged into a single connector. The external terminals also project laterally outwardly beyond the housing envelope and thereby enlarges the required space for the thermostat. FR-A-2 284 177 discloses a switch having ring contacts surrounding a central contact. A movable contact progressively bridges the ring contacts and the central contact. External terminals extend from the ring contacts and the central contacts. FR-A-2 271 650 discloses a double pole, double throw switch. Contact members are interengaged to establish a complete conductive path between movable contacts. The movable contacts simply bridge two fixed contacts. FR-B-2 312 098 discloses a double electrical switch having a pair of contactors each having fixed contacts and movable contacts but there are no external terminals arranged in side-by-side relationship. US-A-4,041,433 discloses a thermostat having a single switch with its contacts connected to external terminals that extend laterally of the housing in opposite directions. It is a principal object of the present invention to provide an improved thermostat having in-line connector terminals. Specifically, the object of the invention is to overcome the aforementioned difficulties by the provision of a thermostat wherein terminal members are mounted in a very confined space. To achieve this, the thermostat of the invention is characterized by the features claimed in the characterizing part of claim 1. According to the invention, the connector terminals are parallel to one another and are arranged in equidistantly spaced side-by-side relationship and aligned along a common axis, that extends perpendicular to the connector terminals and to the direction in which they project from the housing. The terminal members are attached to the housing at locations spaced both axially and circumferentially from one another. Advantageous embodiments of the invention are claimed in the subclaims. In one embodiment of the present invention, the thermostat of the type described has a pair of switches having movable arms axially spaced from one another in aligned relationship. The terminal members connected with the switch contacts have connector terminals aligned along a common axis externally of the thermostat housing. The movable arms of the switches have longitudinal axes lying in a plane extending substantially perpendicular to the common axis of the connector terminals. In one arrangement, the terminal members are mounted in the thermostat housing at locations which are spaced both circumferentially and axially from one another. In such an arrangement, the housing includes a plurality of steps on which the terminal members are secured. Two of the terminal members have fixed switch contacts mounted thereon, and the other two terminal members are connected with movable switch arms having movable contacts thereon. Each terminal member has a substantially flat base and a connector terminal extending substantially perpendicular therefrom. Each connector terminal has a different length from its base to its free end. In another arrangement, there are three connector terminals aligned along a common axis to define opposite outside terminals and a central terminal. One contact in each of a pair of switches is connected with the central terminal. In this embodiment, one contact is a fixed contact in one of the switches, and the other contact is a movable contact in the other of the switches. It is also an object of the invention to provide the contacts of a pair of switches with special terminal members such that connector terminals on the terminal members are aligned along a common axis externally of a housing. It is a further object of the invention to provide an improved thermostat wherein terminal members are mounted in a very confined space, and are so shaped that connector terminals thereon are aligned along a common axis. It is another object of the invention to provide a three terminal thermostat having a pair of switches wherein one contact in each switch is connected with a central one of the terminals. Brief Description of the Drawing Figure 1 is an elevational view of the connector terminal end of a thermostat constructed in accordance with the present application; Figure 2 is a cross-sectional elevational view taken generally on line 2-2 on Figure 1; Figure 3 is a cross-sectional elevational view taken generally on line 3-3 of Figure 1; Figure 4 is a plan view taken generally on line 4-4 of Figure 3; Figure 5 is a plan view looking into the hollow interior of a housing; Figure 6 is a cross-sectional elevational view taken generally on line 6-6 of Figure 5; Figure 7 is a cross-sectional elevational view taken generally on line 7-7 of Figure 5; Figure 8 is a cross-sectional elevational view taken generally on line 8-8 of Figure 5; Figure 9 is a cross-sectional elevational view taken generally on line 9-9 of Figure 5; Figure 10 is a plan view of a bottom fixed contact terminal member; Figure 11 is an elevational view taken generally on line 11-11 of Figure 10; Figure 12 is an elevational view taken generally on line 12-12 of Figure 10; Figure 13 is a plan view of a bottom movable switch arm terminal member; Figure 14 is an elevational view taken generally on line 14-14 of Figure 13; Figure 15 is an elevational view taken generally on line 15-15 of Figure 13; Figure 16 is a plan view of a top fixed contact terminal member; Figure 17 is an elevational view taken generally on line 17-17 of Figure 16; Figure 18 is an elevational view taken generally on line 18-18 of Figure 16; Figure 19 is a plan view of a top movable switch arm terminal member; Figure 20 is an elevational view taken generally on line 20-20 of Figure 19; Figure 21 is an elevational view taken generally on line 21-21 of Figure 19; Figure 22 is a partial perspective illustration showing how the terminal members are mounted within a housing; Figure 23 is a cross-sectional elevational view similar to Figure 3, and showing another embodiment having three terminal members; Figure 24 is a top plan view of another three terminal embodiment; Figure 25 is a cross-sectional elevational view taken generally on line 25-25 of Figure 24; Figure 26 is a cross-sectional elevational view taken generally on line 26-26 of Figure 24; and Figure 27 is an exploded perspective illustration of the embodiment of Figures 24-26. Description of Preferred Embodiments Referring now to the drawing, wherein the showings are for purposes of illustrating preferred embodiments of the invention only and not for purposes of limiting same, Figure 1 shows a thermostat A having a hollow generally cylindrical housing B. A cover member C attached to housing B has slots therein through which connector terminals 10, 12, 14 and 16 project. Cover member C has an upstanding peripheral wall 20 surrounding connector terminals 10-16 in outwardly-spaced protective relationship thereto. Connector terminals 10-16 are aligned along a common axis 22 extending perpendicular to and intersecting housing longitudinal axis 24. Connector terminals 10-16 are in the form of flat spade-like members extending parallel to one another, and common axis 22 extends substantially perpendicular to the opposite flat faces of the connector terminals. Figure 2 shows a pair of switches mounted within housing B. One switch has a fixed contact 30 mounted on a terminal member D, and a movable contact 32 mounted on a movable arm 34 connected with a terminal member E. The other switch has a fixed contact 38 mounted on a terminal member F, and a movable contact 40 mounted on a movable arm 42 which is connected with a terminal member G. A cup member H receives one end of housing B, and has circumferential shoulders 50, 52 on which peripheral portions of bimetal snap discs 54, 56 are supported. The bimetal discs are adapted to operate the two switches at two different temperatures. Bimetal snap disc 54 has a central hole therethrough for freely receiving a ceramic rod 60 which extends freely through a ceramic sleeve 62. Sleeve 62 extends freely through a suitable central hole in the bottom of housing B. Sleeve 62 cooperatively engages a dimple 64 on switch arm 42, and rod 60 engages a dimple 66 on switch arm 34. Rod 60 extends freely through a suitable hole in switch arm 42. When the design temperature of bimetal snap disc 54 is reached, the disc will snap upwardly from the position shown in Figure 2 for moving sleeve 62 upwardly along with switch arm 42 for separating contacts 38, 40. When the design temperature of bimetal snap disc 56 is reached, the disc will snap upwardly from the position shown for moving rod 60 upwardly along with switch arm 34 to separate contacts 30, 32. As shown in Figure 3, housing B and cover C have outwardly extending ears 70, 72 with suitable aligned holes therethrough for receiving rivets 74 to secure the cover to the housing. Terminal members D, E, F and G are specially shaped and mounted for enabling alignment of connector terminals 10, 16 along a common axis as will become apparent as the description proceeds. Figure 5 shows housing B as having a generally cylindrical cavity with central hexagonal hole 76 extending through the bottom thereof for receiving the ceramic sleeve 62 of Figures 2 and 3. The interior of the cavity is provided with a plurality of circumferentially and axially-spaced different levels or steps 80, 82, 84 and 86. Each level has a suitable rivet receiving hole therethrough as at 90, 92, 94 and 96. As shown in Figures 7 and 8, bores 102, 104 and 106 extend inwardly from the bottom of housing B in alignment with rivet receiving holes 92, 94 and 96 for reducing the thickness of the material at the terminal mounting steps to reduce the rivet length required. Figures 10-12 show terminal member F having a substantially flat arcuate base portion 110 with integral connector terminal 10 extending upwardly substantially perpendicular thereto. Connector terminal 10 and fixed contact 38 are located at opposite end portions of base 110, and a rivet receiving hole 112 is located intermediate connector terminal 10 and fixed contact 38. Figures 13-15 show terminal member G having integral connector terminal 12 extending upwardly therefrom substantially perpendicular thereto. Base 120 has one end portion of movable arm 42 staked thereto and extending therefrom past connector terminal 12. Aligned rivet receiving holes 122 are provided in base 120 and the end portion of switch arm 42 secured thereto. The hole in switch arm 42 through which rod 60 of Figure 2 freely extends is shown at 65 in Figure 13. Figures 16-18 show terminal member D having substantially flat arcuate base portion 130 with connector terminal 16 extending upwardly therefrom substantially perpendicular thereto. A suitable rivet receiving hole 132 in base 130 is located intermediate connector terminal 16 and fixed contact 30 at opposite end portions of base 130. Figures 19-21 show terminal member E having a substantially flat arcuate base portion 140 with integral connector terminal 14 extending upwardly therefrom substantially perpendicular thereto. One end portion of movable switch arm 34 is staked to base 140 as generally indicated at 141. Movable switch arm 34 extends outwardly from base 140 past connector terminal 14. A rivet receiving hole 142 is provided in base 140. All of the terminal members shown in Figures 10-21 are of different shapes, and their respective connector terminals have different lengths from their respective flat bases to the free ends thereof. The connector terminals are also bent sideways perpendicular to their flat dimension and/or deformed parallel to their flat dimension in order that all of the connector terminals will be equidistantly spaced from one another and aligned along a common axis. Figures 4 shows hollow rivets 150, 152 and 154, respectively, securing terminal members D, E and F in position within housing B. Figure 2 shows hollow rivet 156 securing terminal member G within housing B. Figure 22 is a diagrammatic exploded perspective showing the general interior shape of housing B with the various steps therein at different levels. Figure 22 also shows how the various terminal members are positioned and secured within the housing. In the arrangement shown and described, the pair of switches are located one above the other, with the longitudinal axes of switch arms 34, 42 lying in a common plane which bisects housing B and extends perpendicualr to the common axis along which the connector terminals 10-16 lie. The longitudinal axes of switch arms 34, 42 also extend perpendicular to the common axis along which connector terminals 10-16 lie. As shown in Figure 2, all of fixed and movable contacts 30, 32, 38 and 40 of the pair of switches are aligned along a common axis extending substantially parallel to thermostat longitudinal axis 24. The opposite outside connector terminals 10, 16 of Figure 3 are associated with the fixed switch contacts, while the inside connector terminals 12, 14 are associated with the movable switch contacts. Figure 23 shows an alternative embodiment having only three connector terminals, and with parts common to the embodiment of Figures 1-22 being identified by common reference numbers and letters. Base 130′ of terminal member D′ has an integral vertical depending leg portion 131 terminating in a reversely extending subbase 133. Base 130′ and subbase 133 are vertically spaced from one another in parallel relationship. Switch contacts 30 and 38 are both attached to terminal member D′. Contact 30 of one switch is welded to base 130′, while contact 38 of the other switch is welded to subbase 133. This arrangement provides aligned connector terminals 12, 14 and 16′, with one contact of each switch being attached to connector terminal 16′. Figures 24-27 show another termostat A2 having three terminal members aligned along a common axis, and with the intermediate terminal being common to both switches. In the embodiment of Figures 24-27, terminal members E, F having connector terminals 14, 10 are substantially the same as in the embodiment of Figures 1-22. Terminal member G′ includes a substantially flat base portion 172 having connector terminal 12′ extending upwardly therefrom along a longitudinal axis 174. A pair of ears 120′, 170 extend laterally from base portion 172 on one side thereof and substantially perpendicular thereto. Ears 120′, 170 are spaced-apart in directions both perpendicular and parallel to axis 174. Ears 120′, 170 are also located on opposite sides of connector terminal 12′ in a direction parallel to the width dimension of connector terminal 12′. Ear 170 has a fixed switch contact 30′ connected therewith and a rivet receiving hole 176. Ear 120′ has a flexible switch arm 42′ connected therewith and carries a movable switch contact 40′ at the outer end portion thereof. Contacts 30′, 40′ are substantially aligned generally parallel to axis 174. Switch arm 42′ has a hole 64′ therein for receiving rod 60, and a dimple 65′ for cooperation with sleeve 62. Ear 120′ and switch arm 42′ have a hole 122′ therethrough for receiving a rivet. Fixed and movable contacts 30′, 32 are provided in one switch, while fixed and movable contacts 38, 40′ are provided in the other switch. The two switches are operated in succession by operation of the bimetallic discs 54, 56, and cooperation with rod 60 and sleeve 62 as described in the other embodiments. Intermediate or central connector terminal 12′ is common to both switches. Thus, one contact in each switch is connected with terminal member G′. Preferably, terminal member G′ carries a fixed contact of one switch and a movable contact of the other switch. As shown in Figure 24, connector terminals 10, 12′ and 14 are aligned along a common axis 22 extending perpendicualr to the flat width dimension of the connector terminals. This provides a pair of opposite outside connector terminals 10, 14 and an intermediate or central connector terminal 12′. The thermostat has a pair of switches, each having a pair of contacts, and one contact in each switch is connected with intermediate connector terminal 12′. In the arrangement of the present application, all of the terminal members are substantially directly connected with their respective contacts instead of being connected thereto through another adaptor member or the like. The improved arrangements of the present application make it possible to mount three or four terminal members in a very confined space while enabling alignment of three or four external connector terminals along a common axis.

Claims: A thermostat (A) having a hollow housing (B) containing a pair of switches, each switch having a pair of contacts (30,32,38,40;30′,32,38,40′) including a fixed contact (30,38;30′,38) and a movable contact (32,40;32,40′), each contact (30,32,38,40;30′,32,38,40′) being connected to a terminal member (D,E,F,G;D′,E,G;E,F,G′), each said terminal member (D,E,F,G;D′,E,G,E,F,G′) having a connector terminal (10,12,14,16;10,12′,14;12,14,16′) projecting externally of said housing (B) adjacent one another in parallel spaced-apart relationship, said connector terminals (10,12,14,16;10,12′,14;12,14,16′) being at least three in number, and each said switch contact (30,32,38,40;30′,32,38,40′) being permanently connected to its respective terminal member (D,E,F,G;D′,E,G;E,F,G′) and remaining so connected with the same respective terminal member in all relative positions between said fixed (30,38;30′,38) and movable contacts (32,40;32,40′) of said pair of switches, characterized by said connector terminals (10,12,14,16;10,12′,14;12,14,16′) projecting externally of said housing (B) in the same direction in equidistantly-spaced relationship and being aligned side-by-side along a common axis (22) that extends perpendicular to said connector terminals (10,12,14,16;10,12′,14;12,14,16′) and to the direction in which they project from said housing (B), and in that said terminal members (D,E,F,G;D′,E,G;E,F,G′) are attached to said housing (B) at locations (80,82,84,86;82,84,86) that are each spaced both axially and circumferentially from one another. The thermostat of claim 1, characterized in that all of said switch contacts (30,32,38,40;30′,32,38,40′) are aligned along a common axis (22). The thermostat of claim 1, characterized in that each said switch includes a movable arm (34,42; 34,42′), said arms being spaced-apart one above the other in aligned relationship. The thermostat of claim 3, characterized in that said arms (34,42;34,42′) have longitudinal axes laying in a common plane extending substantially perpendicular to said common axis (22) along which said connector terminals (10,12,14,16;10,12′,14;12,14,16′) extend. The thermostat of claim 1, characterized in that all of said terminal members (D,E,F,G;D′,E,G;E,F,G′) have a different shape. The thermostat of claim 1, characterized in that two of said terminal members (D,F;F,G′) have said fixed contacts (30,38;30′,38) mounted thereon, said movable contacts (32,40;32,40′) being mounted at one end portion of movable arms (34,42;34,42′), and two of said terminal members (E,G;E,G′) being attached to the opposite ends of said movable arms (34,42;34,42′). The thermostat of claim 1, characterized in that one of said terminal members (D′;G′) is connected with a contact (30,38;30′,40′) in each of said switches. The thermostat of claim 7, characterized in that said one terminal member (G′) is connected with a fixed contact (30′) in one of said switches and with a movable contact (40′) in the other of said switches. The thermostat of claim 1, characterized in that each said terminal member (D,E,F,G;D′,E,G;E,F,G′) includes a substantially flat base (110,120,130,140) having a said connector terminal (10,12,14,16;10,12′,14;12,14,16′) extending substantially perpendicular therefrom. The thermostat of claim 9, characterized in that each said connector terminal (10,12,14,16;10,12′,14;12,14,16′) on each said terminal member (D,E,F,G;D′,E,G;E,F,G′) has a different length from its base (110,120,130,140) to its free end. The thermostat of claim 1, characterized in that said housing (B) has a plurality of internal steps (80,82,84,86) at different circumferential and axial positions therein, one of said terminal members (D,E,F,G;D′,E,G;E,F,G′) being attached to each of said steps. The thermostat of claim 1, characterized in that said housing (B) has a longitudinal axis (24), each said movable contact being attached to an elongated movable arm (34,42;34,42′), said arms being spaced-apart from one another in a direction parallel to said longitudinal axis (24), and said arms (34,42;34,42′) being in parallel aligned relationship to one another. The thermostat of claim 12, characterized in that said arms (34) have longitudinal arm axes extending substantially perpendicular to said common axis (22).

Inventors: HOLDEN RONALD LEROY, PLACE DONALD EDWARD, HOLDEN, RONALD LEROY, PLACE, DONALD EDWARD
Applicants: EMERSON ELECTRIC CO, EMERSON ELECTRIC CO.
Application year: 1988
Main classification: H01H1
IPC codes: H01H37, H01H1