Electrical device with guided return spring

Abstract

A contactor device includes a movable contact configured to selectively open / close an electrical circuit. The switch device can include a shaft coupled to the movable contact and a plunger coupled to the shaft. The plunger and / or the shaft are biased toward an open position by a return spring. A spring guide maintains a position of the return spring relative to the return spring, e.g., to reduce or prohibit contact of the return spring and the shaft.

Description

ELECTRICAL DEVICE WITH GUIDED RETURN SPRINGFIELD OF THE TECHNOLOGY

[0001] The subject disclosure relates to electrical switching devices, such as contactor devices and electrical fuse devices, and more particularly to improved contactor devices with return springs.BACKGROUND OF TECHNOLOGY

[0002] Many conventional devices are known to selectively power on or off electrical devices. Electrical contactors, e.g., high-voltage DC contactors, and fuses, e.g., electrical fuses and / or pyrotechnic fuses, are conventionally available and used in electrical systems. Contactors may be configured to interrupt or complete a circuit to control electrical power to and / or from a device.

[0003] In many conventional systems, a contactor is configured as a switch, e.g., to selectively allow / disallow current flow. In some examples, one or more movable contacts may be coupled to a shaft. In these examples, the shaft may be movable, e.g., by an actuator, to selectively move the movable contact(s) into and out of contact with one or more fixed contacts. In some examples, the shaft (and the movable contact(s)) may be biased away from the fixed contact(s), e.g., to “open” the contactor and prevent current flow through the contactor. For example, a return spring may bias the shaft to an open position. However, in some of these conventional arrangements, the return spring may be susceptible to failure owing to misalignment and / or unwanted interference with other components of the contactor.

[0004] Accordingly, there is a need in the art for improved switching devices and methods of making such devices. There also is a need in the art for improved devices with increased life spans and / or reduced complexity and / or cost.SUMMARY OF THE TECHNOLOGY

[0005] The subject technology relates to improved electrical devices and methods of making and using those devices. In examples, aspects of this disclosure relate to improved switching devices with an integrated return spring guide. For example, aspects of this disclosure may relate to reducing wear on return springs used to bias movable contacts. This reduced wear may result in longer life of the contactor, thereby requiring less frequency maintenance and / or replacement.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] So that those having ordinary skill in the art to which the disclosed systems and techniques pertain will more readily understand how to make and use the same, reference may be had to the following drawings.

[0007] FIG. 1 is a perspective, section view of an electrical device, including a housing and electrical components, in accordance with aspects of this disclosure.

[0008] FIG. 2 is a partial cross-sectional view of an alternative electrical device, in accordance with aspects of this disclosure.

[0009] FIG. 3 is a partial cross-sectional view of an alternative electrical device, in accordance with aspects of this disclosure.DETAILED DESCRIPTION

[0010] The subject technology overcomes many of the prior art problems associated with electrical devices. In brief summary, the subject technology provides improved electrical devices including a contactor design that may have improved performance and / or longer functional life compared to other conventional electrical devices. In examples, the electrical device may have two discrete operation states, including a first operating state and a second operating state. In the first operation state, the device is open, e.g., such that no voltage or current flows through the device. In the second operating state, the device is closed. In examples, the electrical device can include a coil that is energized to cause one or more movable contacts to move into contact with one or more fixed or stationary contacts, thereby completing a circuit, e.g., to configure the device in the second operating state. In the second operating state, current, e.g., from a high voltage source, may flow through the device.

[0011] In aspects of this disclosure, the electrical device can include an actuator assembly that cooperates with the coil to selectively configure the electrical device in the first or second operating state. For example, the actuator assembly may include the movable contact(s) and a shaft that is coupled to the movable contact(s). The actuator assembly can also include a plunger coupled to the shaft, e.g. at a position spaced from the movable contact(s). In the electrical device, the plunger is positioned in a magnetic field generated by the coil. Accordingly, energizing the coil causes the plunger to move, which in turn causes the coupled shaft to move, which results in the movable contact(s) moving into contact with the stationary contact(s). The actuator assembly of the electrical device also includes a return spring that is configured to bias the movable contact(s). For example, the return spring may be configured to bias the movable contact(s) away from the stationary contact(s) (e.g., in a normally open contactor) or toward the stationarycontact(s) (e.g., in a normally closed contactor). For example, when the coil is deenergized, the return spring applies a biasing force on the plunger to move the plunger, shaft, and the movable contact(s) relative to the stationary contact(s).

[0012] In examples of this disclosure, the return spring may be a compression spring that is disposed along a length of the shaft, e.g., such that the spring coils wrap around the shaft. Also in examples, an end of the return spring can rest on or contact an end of the plunger.

[0013] Aspects of this disclosure also include a spring guide that is configured to reduce or prevent contact of the spring and the shaft. In use, the electrical device may be regularly cycled between the closed and open operating states, e.g., by energizing and deenergizing the coil. During this cycling, the shaft moves relative to the return spring. In some conventional examples, this relative movement may cause rubbing or other destructive contact between the shaft and the return spring. For instance, repeated contact may result in wear, deformation, breakage, destruction, and / or other failure associated with the return spring and / or the shaft. Such failure may result in the electrical device being inoperable or otherwise unfit for operation. Accordingly, the spring guide of this disclosure may prevent such failures may reducing or eliminating this destructive contact.

[0014] In some aspects of this disclosure, the spring guide may be formed as a protrusion, such as an annular protrusion, that extends from an upper surface of the plunger. The protrusion can have an outer extent, e.g., an outer diameter, greater than an outer diameter of the shaft, but smaller than an inner diameter of the spring (or the coils of the spring). Accordingly, an end of the spring that contacts the plunger is retained around the protrusion, and thus in a position spaced from the shaft. In some examples, the protrusion can have angled or tapered sidewalls, e.g., suchthat the protrusion has a smaller diameter at a position spaced from the upper surface of the plunger and a larger diameter proximate the upper surface. In other examples, the protrusion can be substantially cylindrical, e.g., with a substantially constant diameter or extent relative to the shaft in the axial direction.

[0015] In other aspects of this disclosure, the spring guide may include a channel or indentation formed in the upper surface of the plunger. For example, the spring guide can include a circular channel disposed around a shaft opening in the plunger. The channel is sized and configured such that an end of the return spring extends into the channel, with sides of the channel inhibiting lateral movement of the spring. Stated differently, the channel may be configured to capture the end of the return spring at a position spaced from the shaft and prevent the spring from “walking” laterally relative to the shaft.

[0016] In still further aspects of this disclosure, the spring guide may be a sleeve configured for positioning between the shaft and the return spring. For example, the sleeve may have an inner diameter larger than an outer diameter of the shaft and an outer diameter smaller than an inner diameter of the return spring. Accordingly, the sleeve can be positioned around the shaft and the spring can be positioned around the sleeve. The sleeve may be formed of a material, such as a polymer, that is relatively non-destructive to the return spring (and the shaft). In examples described herein, the sleeve may contact the upper surface of the plunger. In other examples, the plunger can include a bore for containing or otherwise seating the sleeve and / or the sleeve and at least a portion of the return spring.

[0017] Without limitation, the devices and techniques described herein may provide improved electrical devices, which may be less complex, may be cheaper to manufacture and / oruse, and / or that may have improved safety and / or result in improved system protection, when compared to similar conventional systems. For instance, as discussed above, the use of the spring guide as detailed herein may result in reduced destruction and failure caused by rubbing of the return spring with the shaft. In some examples, inclusion of the spring guide can also or alternatively allow for use of a simpler or cheaper return spring. For example, some conventional electrical devices may incorporate a spring with ground or flat ends. Such springs may be used to increase a contact area between the spring and the plunger, which may reduce relative lateral movement (e.g., relative to a spring with a rounded end coil). However, such springs may be more expensive and / or require extra manufacturing steps to create. The spring guides according to this disclosure may restrain lateral movement of the spring regardless of the profile of the end of the return spring.

[0018] While aspects of this disclosure may be particularly useful in certain applications, like DC contactors for use in high voltage electrical systems, the systems and techniques described herein may be useful with any electrical devices that incorporate return springs.

[0019] Aspects of the disclosure will now be explained in more detail with reference to the Figures.

[0020] FIG. 1 is a cross-sectional view of an electrical device 100. In examples of this disclosure, the electrical device 100 may be a switch or contactor assembly, such as a DC contactor. In other examples, the electrical device may be a hybrid device, e.g., that includes a fuse or disconnect (such as a pyrotechnic disconnect). As will be appreciated from this disclosure, aspects of this disclosure may be used with any device that incorporates a return spring to bias one or more movable contacts from a fixed contact.

[0021] In the illustrated example, the electrical device 100 includes an electrical device housing 102. The housing 102 includes a housing base 104 disposed between an upper housing portion 106 and a lower housing portion 108. In the example of FIG. 1, the upper housing portion 106 is configured to cooperate with the housing base 104. In examples, the switch assembly housing base 210 and portions of the upper housing portion 106 may be metal parts, e.g., steel parts, welded to each other. The upper housing portion 106 defines, at least in part, an upper housing volume 110. In some examples, the upper housing volume 110 may be a hermetically- sealed volume. An electronegative gas may be contained in the upper housing volume 110. This hermetically sealed configuration can help mitigate or prevent electrical arcing between adjacent conductive elements, and in some embodiments, helps provide electrical isolation between conductive contacts, as detailed further herein. In some examples, the upper housing volume 110 can be under vacuum conditions, and can be hermetically sealed using known means of generating hermetically sealed electrical devices.

[0022] Features of the electrical device 100 are disposed in the upper housing volume 110. For example, the view of FIG. 1 shows two fixed contacts 112 coupled to the upper housing portion 106. The fixed contacts 112 are disposed partially in the upper housing volume 110 and are configured to electrically connect internal components (detailed further herein) of the electrical device 100 to external circuitry, for example, to an electrical system or device. For example, the fixed contacts 112 may be terminals configured to facilitate connection of first electrical leads (not shown) from a voltage source to second electrical leads (also not shown) associated with a load to be powered by the voltage source, the fixed contacts 112, e.g., as fixed, or stationary contacts.

[0023] The electrical device 100 also includes a movable contact 114. As detailed further herein, the movable contact 114 is movable between a first position spaced from the fixed contacts112 and a second position contacting the fixed contacts 112. The first position is shown in FIG.1, and the movable contact 114 may be moved upward (in the orientation of FIG. 1) from the illustrated position to the second position. In the illustrated example, the movable contact 114 is a generally elongate member that, in the second position, not illustrated but just described, can simultaneously contact both of the fixed contacts 112. Accordingly, the movable contact 114 can selectively couple the two fixed contacts 112, to facilitate current flow between the fixed contacts 112 and thus through the electrical device 100.

[0024] The electrical device 100 also includes an actuator assembly 116 configured to, among other functions, facilitate selective opening and closing of the electrical device 100, e.g., by facilitating selective movement of the movable contact 114 into and out of contact with the fixed contacts 112. In examples, the actuator assembly 116 can include the movable contact 114 and / or may be operatively coupled to the movable contact 114.

[0025] As illustrated in FIG. 1., the actuator assembly 116 is illustrated as including a shaft 118, a coupler 120, and a plunger 122.

[0026] In the example, the shaft 118 is disposed such that a first end 124 (e.g., an upper end in the orientation of FIG. 1) is positioned in the upper housing volume 110 defined by the upper housing 106 and the base 104. The first end 124 is coupled to the movable contact 114, e.g., via the coupler 120. An opposite, second end 126 of the shaft 118 extends through the base 104 into a lower housing volume 128 defined at least in part by the lower housing portion 108. The second end 126 of the shaft 118 is coupled to the plunger 122.

[0027] In more detail, FIG. 1 shows that the coupler 120 that includes a base 130 and opposing spaced sides 132 extending upward (in the orientation of FIG. 1) from the base 130. Inthis example, the opposing sides 132 define openings 134 through which portions of the movable contact 114 extend. Specifically, the movable contact 114 is a substantially elongate member extending from a first end 136 to a second end 138. The movable contact 114 extends through the openings 134 in the spaced sides 132 such that the first end 136 and the second end 138 are disposed on opposite sides of the spaced sides 132 of the coupler 120 (and generally aligned vertically with the fixed contacts 112).

[0028] In the illustrated example, the base 130 of the coupler is secured to the first end 124 of the shaft 118. In examples, the base 130 may be molded onto the first end 124 of the shaft 118. For instance, the base 130 may be a polymeric material formed on the shaft 118 via an overmolding process or the like. In examples, the polymeric material may configure the base to electrically isolate the movable contact 114 from the remaining actuator components (e.g., the shaft 118) and / or portions of the housing 102 (e.g., the base 104).

[0029] In the illustrated examples, the sides 132 of the coupler 120 may be integrated with the base 130. For example, the base 130 may be overmolded over a bottom portion of the sides 132. However, the sides 132 may be otherwise coupled, secured, or attached to the base 130 in other examples. In the illustrated example, the sides 132 may approximate an inverted U-shape to define the openings 134 which provide clearance for the ends 136, 138 of the movable contact 114, as noted above. The movable contact 114 may be movable in the openings 134 relative to the sides 132 and the base 130.

[0030] In the example of FIG. 1, a biasing spring 140 is disposed between the base 130 and the movable contact 114. More specifically, the biasing spring 140 biases the movable contact114 away from the shaft 118 and against a top edge of the openings 134 in the sides 132. Thus, inthe illustrated example, the shaft 118 is secured to the coupler 120 (e.g., to the base 130 of the coupler 120) and the biasing spring 140 biases the movable contact 114 against the top edge of the openings 234 in the sides 232 of the coupler 220. Accordingly, movement of the shaft 118, e.g., along an axis of the shaft 118, will cause corresponding movement of the coupler 120, the biasing spring 140, and the movable contact 114. For example, when the shaft 118 is caused to move downward in the orientation of FIG. 1, the movable contact 114 moves away from the fixed contacts 112. Alternatively, when the shaft 118 is caused to move upward in the orientation of FIG. 1, the movable contact 114 is moved toward, and eventually into contact with, the fixed contacts 112. Continued movement of the shaft 118 in the upward direction (in the orientation of FIG. 1) when the movable contact 114 contacts the fixed contacts 112, can result in continued travel of the coupler 120 relative to the movable contact 114, e.g., resulting from compression of the biasing spring 140. In this example, the biasing spring 140 can compensate for overtravel of the shaft 118, e.g., to prevent destructive contact of the movable contact 114 with the fixed contacts 112. In other examples, the biasing spring 140 may not be included.

[0031] As also illustrated in FIG. 1, the base 130 of the coupler 120 includes a tapered protrusion 142. In examples, the protrusion 142 may be provided to help maintain positioning and / or orientation of the biasing spring 140. For example, an outer diameter of the protrusion 142 may be similar to or slightly smaller than an inner diameter of the biasing spring 140, e.g., to limit or prevent lateral movement of the biasing spring 140 relative to the coupler 120.

[0032] FIG. 1 also shows a lower yoke 144 disposed below and in contact with the movable contact 114. In examples, the lower yoke 144 may be a metal component configured to cooperate with an upper yoke 146 to provide a metallic or conductive “ring” around the movable contact 114 when the movable contact 114 contacts the fixed contacts 112. For example, the lower yoke 144and the upper yoke 146 may cooperate to enhance or control an electromagnetic field generated by current passing through the movable contact 114. In the example, the upper yoke 146 is coupled to the upper housing 106, e.g., such that the shaft 118, the movable contact 114, the coupler 120, and the lower yoke 144 (e.g., the actuator assembly 116) move relative to the upper yoke 146. In other examples, however, the upper yoke 146 may be coupled to the movable contact 114 and / or to the lower yoke 144.

[0033] The configuration of FIG. 1 is for example only. For example, modifications to the actuator assembly 116 are contemplated and will be appreciated by those having ordinary skill in the art with the benefit of this disclosure. For example, the lower yoke 144 and / or the upper yoke 146 may be omitted. Also, in some examples, aspects of the coupler 120 may be omitted. For instance, the shaft 118 may be coupled directly to the movable contact 114, e.g., instead of via the coupler 120. For instance, a hole may be formed the movable contact 114 and the shaft 118 may extend through the hole in one non-limiting example. In this example, the shaft 118 may include a flanged head and the flanged head may contact an upper surface of the movable contact 114. Other example arrangements also are contemplated. Any arrangement in which movement of the shaft causes corresponding movement of the movable contact 114 may be implemented.

[0034] As also shown in FIG. 1, the shaft 118 extends through the base plate 104, such that the second end 126 of the shaft 118 is disposed in the lower volume 128, defined at least in part by the lower housing portion 108. In the illustrated example, an opening 147 or hole is formed in the base 104, and the shaft 118 extends through the opening 147. In the illustrated example, the opening 147 is sized to have a diameter smaller than an outer extent of the coupler 120 (e.g., the base 130 of the coupler 120) such that the coupler 120 contacts the base 104 and does not pass through the opening 147. Also in the illustrated example, an alignment plug 148 is disposed atleast partially in the opening 147. More specifically, the alignment plug 148 is configured for fitting into the opening 147, e.g., via a press fit. When present, the alignment plug 148 also defines an opening through which the shaft 118 extends.

[0035] When used, the alignment plug 148 may facilitate locating one or more additional components of the electrical device 100. For example, the alignment plug 148 extends from the opening 147 (and the base 104) into the lower volume 128. In the illustrated example, a distal end (e.g., spaced from the base 104) of the alignment plug 148 is sized to extend into a plunger tube 150. For example, an inner diameter of the plunger tube 150 and an outer diameter of the alignment plug 148 may be sized to allow for the alignment plug 148 to be disposed in the plunger tube 150. In some examples, the alignment plug 148 can be press fit into the plunger tube 150 (or the plunger tube 150 can be press fit over the alignment plug 148). As detailed further below, the plunger tube 150 can house or otherwise retain the plunger 122.

[0036] As also illustrated in FIG. 1, the alignment plug 148 may also define a bore 152. The shaft 118 passes through the bore 152. Moreover, the bore 152 is sized to receive at least a portion of a return spring 154. In the example, the return spring 154 is a compression spring extending from a first end 156 disposed in the bore 152 (and contacting an inner, bottom surface of the bore 152) of the alignment plug 148 to a second end 158 spaced from the first end 156 along an axis of the return spring 154. The second end 158 of the return spring 154 contacts an upper surface 160 of the plunger 122. In the illustrated example, because the alignment plug 148 is fixed to the base 104 of the housing 102, the return spring 154 biases the plunger 122 away from the base 104, e.g., in a downward direction in the orientation of FIG. 1. Moreover, because the second end 126 of the shaft 118 also is coupled to the plunger 122, the return spring 154 biases the shaft 118 and the movable contact 114, e.g., away from the fixed contacts 112.

[0037] The actuator assembly 116 is driven by a coil 162, e.g., a DC coil, which may be selectively energized. For example, and as shown in FIG. 1, the coil 162 is disposed proximate the plunger tube 150. In examples, the coil 162 is a cylindrical coil that is disposed around the plunger tube 150. The plunger 122 is disposed in the plunger tube 150, and the plunger 122 is movable relative to the plunger tube 150. In examples, the plunger tube 150 may be fixed relative to the coil 162 and the plunger 122 is free to move axially relative to the plunger tube 150 (and the coil 162) in response to activation / deactivation of the coil 206. As detailed above, the plunger 122 is coupled to the second end 126 of the shaft 118. The return spring 154 is positioned on the shaft 118 between the upper surface 160 of the plunger 122 and a lower surface of the housing base 104 (e g., the alignment plug 148 in FIG. 1). The return spring 154 biases the plunger 122 (and thus the shaft 118) away from the base 104, e.g., in a downward direction in FIG. 1. Accordingly, when the coil 162 is not charged, the return spring 154 biases the shaft 118 (via the plunger 122) to distance the movable contact 114 from the fixed contacts 112.

[0038] A magnified section 164 of FIG. 1 shows additional details of the return spring 154, the shaft 118, and the plunger 122. More specifically, the magnified section 164 shows that the return spring 154 is disposed around the shaft 118 and that the second end 158 of the return spring 154 contacts the upper surface 160 of the plunger 122. The magnified section 164 also shows that the plunger 122 includes a spring guide 166. In the illustrated example, the spring guide 166 comprises a protrusion 168 extending above the upper surface 160 of the plunger 122 and surrounding an axial opening 170 in the plunger 122 through which the shaft 118 extends. The spring guide 166 is provided to maintain the return spring 154 at a position spaced from the shaft 118. Thus, in the illustrated example, a maximum extent of the spring guide 166, e.g., a maximum diameter of the protrusion 168 at the upper surface 160 of the plunger 122 in the illustratedexample, is larger than a diameter, or maximum extent, of the shaft 118. However, the spring guide 166 may be sized such that the return spring 154 can extend over and / or around the spring guide 1666.

[0039] Also in the illustrated example, the spring guide 166 includes an angled or tapered outer surface 172, such that the spring guide 166 is substantially frusto-conical. Stated differently, the protrusion 168 comprising the spring guide 166 has a base proximate the upper surface 160 of the plunger 122 that is wider than a width of the protrusion 168 at a position spaced from the base (e.g., spaced from the upper surface 160).

[0040] In examples, the tapered outer surface 172 may aid in properly seating or locating the return spring 154 on the upper surface 160 of the plunger 122, relative to the shaft 118. For instance, should the second end 158 of the return spring 154 become separated from the upper surface 160 of the plunger 122, reengagement of the return spring 154 with any portion of the tapered surface 172 will cause the return spring 154 to re-center relative to the shaft 118, e.g., as the return spring 154 is compressed between the plunger 122 and the alignment plug 148. In other examples, however, the outer surface of the spring guide 166 may be other than tapered. For example, and without limitation, the outer surface of the spring guide 166 may be substantially cylindrical or have some different profde that has substantially constant lateral extent(s) from the shaft. Moreover, although the example of FIG. 1 shows the protrusion 168 as being formed as an annular protrusion, e.g., extending completely around the opening 170, in other examples, the protrusion 168 can include two more protrusions, e.g., which may be spaced circumferentially about the axial opening 170.

[0041] In examples, the spring guide 166 can reduce or prevent lateral movement of the return spring 154 relative to the shaft 118. Accordingly, when the shaft 118 is moved axially relative to the return spring 154, e.g., to open / close the electrical device 100 via energizing / deenergizing the coil 162, the shaft 118 and the return spring 154 will not rub or otherwise contact each other. In some designs, in which the spring guide 166 is not provided, cycling of the of the coil 162 (and thus the shaft 118 and the return spring 154) may cause the spring 154 to “walk” on the upper surface 160 of the plunger 122. For instance, the return spring 154 may walk because the ends of the spring 154 make contact at one point, instead of across the entire spring coil diameter. Accordingly, axial loading on the spring 154, e.g., resulting in compression of the spring 154, may also create an off-axis load on the spring 154. Under repeated cycling, this off-axis force may cause the spring 154 to move laterally relative to the shaft 118. This lateral movement may result in contacting of the spring 154 with the shaft 118, which in turn, may result in failure of the electrical device 100 and / or the spring, e.g., due to breaking, bending, binding, or the like.

[0042] In examples, use of the spring guide 166 may also or alternatively facilitate the use of less expensive components. For example, some conventional designs have implemented a spring that includes closed spring ends and / or spring ends that are ground or otherwise formed to be flat. Flat ends of the spring may better cooperate with the upper surface of the plunger, e.g., by increasing a contact area between the return spring and the plunger, and thus potentially limiting the off-axis loading discussed above. However, forming the flat ends requires additional processing, so such springs may be more expensive. In contrast, the use of the spring guide 166 according to aspects of this disclosure may allow for the use of springs that do not have closed and / or flat ends, which may reduce costs.

[0043] In the example of FIG. 1 , the shaft 1 18 does not have a constant diameter along its axial length. Instead, the shaft 118 has a first diameter along a first axial section 174, e.g., closer to the first end 124 of the shaft 118 and a second diameter along a second axial section 176, e.g., proximate the second end 126 of the shaft 118. In the example, the first diameter of the first axial section 174 is larger than the second diameter of the second axial section 176. Moreover, in the illustrated example, the shaft 118 is coupled to the plunger 122 such that the spring guide 166 is positioned to proximate the second axial section 176. In this arrangement, the outer diameter of the spring guide 166 proximate the upper surface 160 of the plunger 122 may be greater than the outer diameter of the first axial section 174 of the shaft 118, but smaller than the inner diameter of the return spring 154. Moreover, the diameter of the protrusion 168 comprising the spring guide 166 at a position spaced from the upper surface 160 of the plunger 122, e.g., at its narrowest point, may be smaller than the diameter of the first axial section 174 of the shaft 118. Of course, in other examples, the shaft 118 may have a substantially constant outer diameter along more or less of its length and / or may have other profiles.

[0044] Although FIG. 1 illustrates the spring guide 166 as being associated with the plunger 122 and facilitating spacing of the second end 158 of the return spring 154 from the shaft 118, in other examples, a spring guide may also or alternatively be associated with the first end 156 of the return spring 154. For example, and without limitation, a spring guide substantially the same in shape and / or size may be disposed in the bore 152 of the alignment plug 148. For example, a protrusion like the protrusion 168 may extend from the end wall of the alignment plug 148, e.g., toward the plunger 122, and the first end 156 of the return spring 154 may be disposed around the protrusion.

[0045] The example of FIG. 1 shows a normally open contactor, e.g., such that the return spring 154 biases the movable contact 114 away from the fixed contacts 112, and the plunger is actuated against a biasing force of the return spring 154 to close the circuit (e.g., by contacting the movable contact 114 to the fixed contacts 112). Aspects of this disclosure may also be applied to other contactor constructions, including normally closed contactors. In a normally closed contactor, the return spring 154 may bias the movable contact toward the fixed contacts 112 and the plunger is actuated against the biasing force of the return spring 154 to open the circuit (e.g., by separating the movable contact 114 from the fixed contacts). The spring guide 166 and modifications thereto described herein may be used with any spring configuration, e.g., to reduce wear as detailed herein.

[0046] As noted above, in examples the spring guide 166 reduces or prevents contact of the return spring 154 with the shaft 118. For example, the spring guide 166 may maintain spacing of the return spring 154 relative to the shaft 118 and / or may reduce or eliminate lateral movement of the return spring 154 relative to the shaft 118. In addition to modification of the spring guide 166 contemplated above, in other examples a spring guide may be formed differently from the example of FIG. 1. For example, FIGS. 2 and 3 show alternative example electrical devices according to this disclosure.

[0047] FIG. 2 is a partial cross-sectional view of an electrical device 200. The view of FIG. 2 generally corresponds to the magnified portion of FIG. 1, and the electrical device 200 may include any or all of the features of the electrical device 100. In FIG. 2, the same reference numerals used in FIG. 1 are used to identify the same features. Features of FIG. 1 not shown in FIG. 2 may be included in the electrical device 200, and / or the electrical device 200 can include other components or features.

[0048] In more detail, FIG. 2 shows a portion of the shaft 118 extending through and coupled to the plunger 122. FIG. 2 also shows the return spring 154 surrounding the shaft 118 and extending between the upper surface 160 of the plunger 122 and the alignment plug 148 (only a portion of which is illustrated). Unlike the example of FIG. 1, in the electrical device 200, a spring guide 202 is formed as a channel 204 or indentation in the upper surface 160 of the plunger 122. The channel 204 is generally circular in shape and is coaxial with the opening 170 extending through the plunger 122 and / or with the shaft 118. In the illustrated example, the channel 204 has an arcuate profde, generally configured to cooperate with the second end 158 of the return spring 154. Specifically, the channel 204 is sized to receive at least a portion of an end or terminal coil 206 of the return spring 154. In the illustrated example, the channel 204 has a radial width, w, and the channel 204 extends a depth, d, below the upper surface 160 of the plunger 122. In examples, the width, w, is larger than a diameter of the end coil 206 and the depth, d, is sufficient to seat or otherwise retain at least a portion of the end coil 206, e.g., to restrict lateral movement of the end coil 206.

[0049] In the example of FIG. 2, the channel 204 is illustrated as having an arcuate, e.g., semi-circular profile. However, the spring guide 202 is not limited to an arcuate profile for the channel 204. The channel 204 may be any profile that cooperates with the return spring 154 to reduce or prevent lateral movement of the return spring 154 and / or to space the return spring 154 from the shaft 118. For instance, in examples in which the end coil 206 includes a flat end (not shown), it may be desirable for the channel to include a corresponding flat surface, e.g., parallel to the upper surface 160 of the plunger 122, to provide a greater contact area for contacting the flat end of the end coil 206. Without limitation, the channel 204 may have a profde that includes one or more flats, arcs, and / or other contours.

[0050] FIG. 3 is a partial cross-sectional view of an electrical device 300. The view of FIG. 3 generally corresponds to the magnified portion of FIG. 1, and the electrical device 300 may include any or all of the features of the electrical device 100. In FIG. 3, the same reference numerals used in FIG. 1 are used to identify the same features. Features of FIG. 1 not shown in FIG. 3 may be included in the electrical device 300, and / or the electrical device 300 can include other components or features.

[0051] For example, FIG. 3 shows a shaft 302 that generally corresponds to the shaft 118. The shaft 302 is coupled to a plunger 304, which generally corresponds to the plunger 122. In the example, the shaft 302 differs from the shaft 118 in that it has a continuous outer diameter. FIG. 3 also shows the return spring 154 surrounding the shaft 302 and extending between the plunger 304 and the alignment plug 148. Unlike the example of FIG. 1, in the electrical device 300, a spring guide 306 is formed as a separate sleeve 308. The sleeve 308 is generally cylindrical, defining a central opening 310 and an outer sidewall 312. The shaft 302 extends through the central opening 310 and the outer sidewall 312 extends axially through the return spring 154. Stated differently, the sleeve 308 is disposed between the shaft 302 and the return spring 154. Accordingly, during cycling of the plunger 304 generally as described herein, any lateral movement of the return spring 154 causes the return spring 154 to rub against the outer sidewall 312 of the sleeve 308, e.g., instead of the shaft 302. The sleeve may be made of a material, such as a polymer, that is selected to reduce wear in the presence of such rubbing.

[0052] In the example of FIG. 3, the sleeve 308 extends from a first end 314 contacting an upper surface 318 of the plunger 304 to a second end 316. In the example, the second end 316 is spaced from the end wall (not shown in FIG. 3) of the alignment plug 148. As will be appreciated, the second end 316 may be spaced by a length that is equal to or less than a stroke of the plunger304. That is, because the sleeve 308 moves with the plunger 304, a length of the sleeve 308 may be selected to prevent the sleeve 308 from obstructing travel of the plunger 304 and shaft 302. In examples, the sleeve 308 may serve similar or the same functionality as the protrusion 168 described above, but whereas the protrusion 168 is formed integrally with the plunger 122, the sleeve 308 may be separate from the plunger 304. In examples, the separate sleeve 308 may be desirable, e.g., to facilitate use of the same plunger in different applications, including but not limited to application in which different return springs and / or shafts are used.

[0053] In other examples, other features of the electrical device 300 may be modified to facilitate use of the sleeve 308 as the spring guide 306. For example, although FIG. 3 shows the first end 314 of the sleeve 308 as contacting the upper surface 318 of the plunger 304, in other examples a bore may be formed in the upper surface 318, with the return spring 154 and the sleeve 308 being disposed at least partially in the bore. In such an example, the return spring is disposed (radially) between the sleeve 308 and an inner sidewall of the bore. In other examples, the bore may be sized to receive only the sleeve, e.g., such that the sleeve 308 extends into the bore, but the return spring sits on or otherwise contacts the upper surface 318 of the plunger 304, as in the illustrated example.

[0054] While the subject technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and / or modifications can be made to the subject technology without departing from the spirit or scope of the subject technology. For example, each claim may depend from any or all claims in a multiple dependent manner even though such has not been originally claimed.

Claims

WHAT IS CLAIMED IS:

1. A switching device comprising: one or more fixed contacts; a movable contact movable relative to the one or more fixed contacts; a shaft coupled to the movable contact, the shaft being movable between a first position that configures the switching device in a closed configuration in which the movable contact contacts the one or more fixed contacts and a second position that configures the switching device in an open configuration in which the movable contact is spaced from the one or more fixed contacts; a return spring through which the shaft extends, the return spring biasing the shaft toward the first position or the second position; and a spring guide maintaining the return spring at a position spaced from the shaft.

2. The switching device of claim 1, further comprising: a plunger coupled to the shaft, wherein the return spring acts on a surface of the plunger to bias the shaft toward the first position or the second position.

3. The switching device of claim 2, wherein the spring guide comprises a protrusion extending from the surface of the plunger.

4. The switching device of claim 3, wherein the protrusion comprises a substantially cylindrical sidewall.

5. The switching device of claim 3, wherein the protrusion comprises an inclined sidewall having a base proximate the surface of the plunger that is wider than a width of the protrusion at a position spaced from the base.

6. The switching device of claim 2, wherein the spring guide comprises a channel formed in the surface of the plunger.

7. The switching device of claim 1, wherein the spring guide comprises a sleeve disposed at least partially around the shaft.

8. The switching device of claim 1, further comprising: a core having an end wall and a sidewall extending from the end wall to define a bore, wherein: the shaft extends through a hole formed in the end wall, and the return spring is at least partially disposed in the bore.

9. The switching device of claim 8, wherein the spring guide comprises a protrusion extending from the end wall and disposed in the bore.

10. The switching device of claim 8, wherein the spring guide comprises a channel formed in the end wall.

11. An electrical device comprising: a housing defining a volume; fixed contacts coupled to the housing and extending into the volume, a movable contact disposed in the volume, an actuator assembly comprising a shaft coupled to the movable contact and a plunger coupled to the shaft, the actuator assembly being configured to move the movable contact between a first position contacting the fixed contacts and a second position spaced from the fixed contacts, the actuator assembly comprising a shaft and a plunger coupled to the shaft, a return spring through which the shaft extends, the return spring contacting the plunger and biasing the plunger to move the movable contact to the first position or the second position; and a spring guide maintaining the return spring at a position spaced laterally from the shaft.

12. The electrical device of claim 11, wherein: the return spring contacts a surface of the plunger; and the spring guide comprises a protrusion extending from the surface of the plunger.

13. The electrical device of claim 12, wherein the protrusion comprises a substantially cylindrical sidewall.234817-4170-2598.

114. The electrical device of claim 12, wherein the protrusion comprises an inclined sidewall having a base proximate the surface of the plunger, the base having a first width that is wider than a second width of the protrusion at a position spaced from the base.

15. The electrical device of claim 14, wherein: the return spring is a compression spring having an inner diameter; and the inner diameter is larger than the first width.

16. The electrical device of claim 14, wherein: the shaft has a first diameter along a first axial length and a second diameter larger than the first diameter along a second axial length; the protrusion abuts the first axial length of the shaft; and the first width is larger than the second diameter.

17. The electrical device of claim 11, wherein: the return spring contacts a surface of the plunger; and the spring guide comprises a channel formed in the surface of the plunger.

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