The present disclosure relates generally to switches, and more particularly to a switch and a sealed contact enclosure for a switch.
It is desirable for an exterior switch, e.g., an exterior vehicle switch, to withstand exposure to extreme weather conditions, abuse from a car wash, off-road activity, etc. Known switches may fail due to moisture ingress into the dry contact area of the switch. In one known configuration, a seal is established by a separate elastomeric membrane that is captured between two rigid components that combine to form a housing for the switch assembly. Screws are used to draw one rigid component toward the other, and fix the two rigid components such that they capture the elastomeric membrane. Features acting to impinge and clamp the elastomeric membrane may be added to the rigid components. The intent is to provide a watertight seal around the entire perimeter of the membrane. This approach to sealing may however be unsatisfactory, since the membrane can shift when coupled to the housing or during the assembly of the screws, thereby compromising the integrity of the seal.
Features and advantages of the subject matter of the present disclosure will be apparent from the following description of embodiments consistent therewith, in which:
The present disclosure is generally directed to a sealed switch assembly. Consistent with various embodiments, a sealed switch assembly may suitably be employed in connection with various automotive applications. For example, a sealed switch consistent with the present disclosure may be suitably employed for actuating the release of a lift gate, vehicle door, etc. Consistent with such applications, the switch assembly may be disposed on the exterior of the vehicle, and may therefore be exposed to the environment. It is recognized, however, that a switch consistent with the present disclosure may be suitably employed in connection with various additional applications, including applications unrelated to vehicular and/or automotive applications.
Referring to
As shown in the transverse cross-sectional view of
The actuation portion 28 may provide a tactile feature, such as the illustrated convex surface. With additional reference to the longitudinal cross-sectional view of
The micro-switch 16 may be at least partially supported by the back cover 14, and/or may be at lest partially disposed in a recess 17 defined in the back cover 14. A connector 34 may be integrally formed with the back cover 14, e.g., via insert molding. As shown, the connector 34 may include one or more electrical contacts 36. The electrical contacts 36 may be electrically coupled to the micro-switch 16. According to one embodiment, the contacts 36 may provide mounting pads, onto which a surface mount micro-switch may be bonded. Various additional structures and/or arrangements may also, or alternatively, be used for provided for electrically coupling the micro-switch to a vehicle system, e.g., a pigtail connector.
In addition to the recess 17 for the micro-switch 16, and the connector 34, the back cover 14 may include spring locating features, such as protrusions 21, 23. The protrusions 21, 23 may locate and/or support the springs 20, 22 on the back cover 14. The back cover 14 may also include an upstanding wall 38 extending therefrom.
In one embodiment, the rocker 18 may be pivotally mounted to convert a linear actuation force applied to the actuation portion 28 into a rocking motion of the rocker 18. The rocker 18 may include a pivot feature on each end, e.g., tab 31 visible in
Consistent with one embodiment, a lubricant may be provided between the over-molded feature 27 on the inside of the actuation portion 28 and the cooperating surface of the rocker 18. The lubricant between the actuation portion 28 and the rocker 18 may reduce or prevent the occurrence of slip and stick between the over-molded feature 27 and the rocker 18 during operation, e.g., when the actuation portion is depressed to actuate the switch. Reducing or preventing slip and stick between the over-molded feature and the rocker may provide a smooth operation of the switch. A variety of suitable lubricants may be used. One suitable lubricant may include a Teflon™ grease, such as a grease with small spherical Teflon™ filler particles.
The over-molded feature 27 overlying at least a portion of the body 26 of the housing 12 may be provided by molding the over-molded feature 27 directly over the body 26. The body 26 may be formed, e.g., by injection molding. The over-molded feature 27 may be over-molded onto the housing in the same molding operation. For example, the mold used for forming the body may be adjusted to provide a second cavity corresponding to the region to include the over-molded feature. A second material, e.g., an elastomer, may then be injected into the second cavity. Alternatively, the over-molded feature 27 may be over-molded onto the body 26 in a separate, e.g., a subsequent, molding operation. The material used for the over-molded feature 27 may vary in durometer and thickness to increase tear resistance and improve or adjust the tactile feel of the switch assembly 10.
In one embodiment, the over-molded feature 27 may be a low durometer thermoplastic elastomer rubber which may seal the switch from the front and along the inside walls of the housing body 26, to the rear of the switch housing 12. In this manner, the over-molded feature may, generally, provide a continuous cavity that may receive at least a portion of the rocker and may receive at least a portion of the micro-switch, enclosed by the back cover. Such a configuration may, at least in part, reduce and/or prevent the ingress of dirt and/or water.
A sealed switch assembly consistent with the present disclosure may protect the internal circuitry and/or components of the switch and the finish panel receiving the switch from the ingress of dirt and/or moisture. Consistent with various aspects of the present disclosure, one or more sealing features may be included to provide the desired protection against the ingress of dirt and/or water. As discussed above, molding the over-molded feature 27 over the housing body 26 may provide a seal between the body 26 and the actuation portion 28. The seal between the body and the actuation portion may provide uniform integrity around the entire perimeter of the actuation portion 28 and the opening 30 defined in the body 26.
According to one aspect, the switch assembly 10 may be configured to provide sealing engagement between the switch housing 12 and the back cover 14. The integrity of the seal between the housing 12 and the back cover 14 may be increased by including an elastomeric beam 44 along the perimeter of the rearwardly extending wall 32 of the body 26. As shown, e.g., in
In one embodiment, the elastomeric beam 44 may be provided as a continuous feature, and may have a generally uniform thickness. To allow a beam 44 of generally uniform thickness, the housing 12 may include a boss or land around each screw hole. The screw holes may, therefore be disposed outside of the continuous beam 44. In this manner, the corresponding holes 46 in the back cover 14 may lie outside of the beam 44 when the switch assembly 10 is complete. In such an embodiment, it may not be necessary to seal the screws 24 and/or screw holes 46, as these openings may not extend into the interior of the switch assembly.
The width of the beam 44 may generally be in the range of from about 0.5 mm to about 1.5 mm. In further embodiments, the width of the beam 44 may generally be in the range from about 0.25 mm to about 10.0 mm. Various other beam widths may also be suitable. The thickness of the beam 44 may generally be in the range from about 0.5 mm to about 1.0 mm. In further embodiments, the thickness of the beam 44 may generally be in the range of from about 0.25 mm to about 3.0 mm. Other beam thicknesses may also be suitable.
The seal integrity between the back cover 14 and the housing 12 may be affected by a number of conditions and/or attributes. For example, the flatness of the housing 12 and the flatness of the back cover 14 may influence the sealing capacity. Similarly, the stiffness of the back cover 14 may affect the uniformity of the seal between the back cover 14 and the housing 12 around the perimeter of the housing 12. The durometer and thickness of the elastomeric material forming the beam 44, as well as the number of screws 24, the diameter of the screws 24, and the distance between the screws 24 may all affect the seal between the back cover 14 and the housing 12. For example, larger diameter screws may be placed further apart.
The sealing capability of the back cover 14 and the housing 12 may be improved by incorporating a rib 48 into the design of the back cover 14, as shown, for example, in
According to another aspect, the switch assembly 10 may be sealed to prevent and/or reduce the ingress of dirt, water, etc. by a seal between the over-molded feature 27 and the housing body 26 at the actuation portion 28. As best shown in
As also shown, the actuation portion 28 may provide a cosmetic surface, with the over-molded feature 27 overlying, and being bonded to, a portion of the body 26 defining the opening 30. The bond between the over-molded feature 27 and the body 26 may allow the elimination of exposed screws, which may not be esthetically appealing, and therefore may not be desired to create a seal across the actuation portion 28. As shown, in an embodiment consistent with the present disclosure, a relatively large flat surface may be provided around the domed feature of the actuation portion 28. The bonded surface area of the over-molded feature 27 and the body 26 around the opening 30 may be sufficient to retain the over-molded feature 27 in position and provide a seal against the ingress of dirt, water, etc.
According to another aspect, a seal may be provided between the housing 12 and a finish panel 50 into which the switch assembly 10 may be assembled. The housing 12 may include a mounting flange 52. The mounting flange 52 may include a beam 54 of elastomeric material which may extend completely around the mounting flange 52. In one embodiment, the beam 54 may extend generally the full width of the mounting flange 52. The seal between the mounting flange 52 and the finish panel 50 may be completed by fixing the switch assembly 10 to the finish panel 50. Fixing the switch assembly 10 to the finish panel 50 may at least partially compress the elastomeric beam 54 around the entire perimeter of the mounting flange 52. Features similar to the rib 48 on the back cover 14 may be included on the finish panel 50 to increase the integrity of the seal between the switch assembly 10 and the finish panel 50, e.g., by creating a line of concentrated stress. Cooperating screw features may also be added to both the switch assembly 10 and to the finish panel 50 to increase the integrity of the seal.
In one embodiment, the elastomeric beam 54 included on the mounting flange 52 may be formed as an over-molded feature. In such an embodiment the elastomeric beam may be bonded to the housing body 26 as a result of the over-molding operation. In one particular embodiment, the elastomeric beam 54 may be formed from the same material as the over-molded feature 27. Furthermore, the elastomeric beam 54 may be formed as part of the over-molding operation during which the over-molded feature 27 is over-molded on the housing body 26. The body 26 may include one or more feed runners 40, 42, which may permit the flow of the elastomeric material from the region of the over-molded feature 27 during over-molding operation to form the elastomeric beam 54. The feed runners 40, 42 may include channels formed in the body 26 that may be filled with the elastomeric material during an over-molding operation.
With particular reference to
As mentioned above, the finish panel 50 may include a bead configured to engage the beam 54, which may increase the seal integrity, e.g., by creating a line of concentrated stress between the finish panel and the beam 54. In additional embodiments, the finish panel and/or the mounting flange 52 or beam 54 may include various features which may improve the seal between the finish panel 50 and the switch assembly 10. As shown in
As mentioned, the housing 12 and/or at least some of the sealing surfaces described herein may be produced by a single over-molding operation, in which the housing body 26 may be molded from a first material and a second, e.g., elastomeric, material may be molded to overlie at least a portion of the body 26 to provide the over-molded feature. In one embodiment, the gate for injecting the elastomeric material may be located on the outer surface of the body 26, e.g., a gate may be located on one or both of the feed runners 40, 42. The feed runners 40, 42 may allow the elastomer to flow to the sealing surface of the mounting flange 52, e.g., to form the beam 54. During molding of the over-molded feature 27, the feed runners 40, 42 may also allow the elastomer to flow into the inner surface of the body 26 to form the actuation portion 28, overlie at least a portion of the inner surface of the rearwardly extending wall 32, and form the beam 44 along the perimeter of the rearwardly extending wall 32 of the body 26.
In one embodiment the thickness of the region of the over-molded feature 27 overlying the inner surface of the rearwardly extending wall 32 may be sized to permit the back cover 14 to be assembled to the housing 12 with minimal force. According to some embodiments, the back cover 14 may engage the housing 12 and remain engaged with the housing 12 during subsequent operations of the assembly operation, for example until the screws 24 are assembled. In one such embodiment, the dimensions of the over-molded feature 27 overlying the inner surface of the rearwardly extending wall 32 may be sized to engaged the upstanding wall 38 of the back cover 14, e.g., and frictionally retain the back cover 14 to the housing 12. Another alternative may include providing a mismatch between the mating radii that extend around the perimeter of the back cover 14 and the housing 12, i.e., a radius on the housing may be smaller than the mating radius on the back cover 14. The mismatch in the mating radii may result in an at least partial interference and a seal between the two radii.
Various alternative structures and/or techniques may be employed to achieve one or more of the seals discussed herein. For example, the seal between the back cover and the housing may include ultrasonic welding of the two components to achieve a seal to prevent and/or reduce the ingress of dirt and/or water. Similarly, the back cover may be bonded to the housing, e.g., via adhesive bonding, solvent bonding, etc. Since alternative techniques for sealing the back cover and the housing may not require an elastomeric material to provide the seal the elastomeric material, e.g., the beam around the perimeter of the rearwardly extending wall, may not be required between the housing and the back cover.
The tear resistance of the over-molded feature at the actuation portion may be varied according to particular applications. For example the tear resistance may be increased by increasing the thickness of the material at the actuation portion and/or by increasing the durometer of the elastomer. The tear resistance of the over-molded feature at the actuation portion may further be increased by incorporating flexible tear resistant feature. For example, the over-molded feature may incorporate a flexible mesh at the actuation portion. The flexible mesh may, in some embodiments, be incorporated as part of the over-molding operation. According to another aspect, the bond between the elastomeric material, e.g., of the over-molded feature 27 and the housing body 26, may be increased by incorporating cross-holes 62 or cavities to create three-dimensional mechanical interlocks between the over-molded feature 27 and the body 26, as shown in
Consistent with a previously discussed embodiment, compression springs may be used to bias the rocker toward a neutral position, i.e., toward the actuation portion and in which the micro-switch is in an open condition. Referring to
A switch assembly consistent with the present disclosure may be completely sealed, and therefore a volume of air may be trapped within the switch assembly. Automotive industries standards require the switch to operate properly between the temperatures of −40 C. and +85 C. During actuation at elevated temperatures, the volume of air may generate an increase in pressure within the switch that could compromise seal integrity. According to one embodiment, an increase in pressure may be avoided by creating a pathway or a hole for air to escape. A relief hole 66, as contemplated herein, may be placed in the connector 36, as depicted in
Therefore, according to one aspect, a switch assembly is provided including a housing having a body and an over-molded feature. The over-molded feature may include a flexible membrane sealing engaged with the body and defining an actuation portion. The housing may be configured to sealingly engage a finish panel. The switch assembly may also include a back cover that is configured to be sealingly coupled to the housing. Additionally, the switch assembly may include a rocker disposed between at least a portion of the actuation portion of the housing and the back cover. The rocker may transmit a force applied to the actuation portion to actuate a switch.
According to another aspect, the present disclosure may provide a sealed switch assembly including a housing having a body and an over-molded feature. The over-molded feature may include a flexible membrane defining at least a portion of an actuation portion. The over-molded feature may also define a sealing beam around at least a portion of a perimeter of a rearwardly extending wall of the body. The sealed switch assembly may also include a back cover that is configured to sealing engage the housing via the sealing beam. The back cover may also include a micro-switch that is at least partially supported by the back cover. A rocker may be pivotally disposed between at least a portion of the actuation portion and at least a portion of the back cover.
According to yet another aspect, a sealed switch assembly is provided including a body having a rearwardly extending wall, and opening, and a mounting flange. An over-molded feature includes a flexible membrane sealing engaged with the body and disposed over at least a portion of the opening. The flexible membrane may define at least a portion of an actuation portion. The over-molded feature may also include a first beam disposed around a perimeter of the rearwardly extending wall and may also include a second beam disposed around the mounting flange. A back cover may include a recess and a micro-switch at least partially disposed in the recess. The back cover may be configured to be sealingly coupled to the body via the first beam. The switch assembly may also include a rocker disposed between at least a portion of the actuation portion and at least a portion of the back cover. The rocker may be pivotally mounted to transmit an actuating force from the actuation portion to the micro-switch.
It should also be understood that the various features and aspects of the exemplary switch assemblies described herein may be combined with one another. Furthermore, the features and aspects of the invention herein are susceptible to use with other switch assemblies in addition to the exemplary assemblies.
The embodiments that have been described herein are but some of the several which utilize this invention and are set forth here by way of illustration, but not of limitation. It is obvious that many other embodiments, which will be readily apparent to those skilled in the art may be made without departing materially from the spirit and scope of the invention.
The present application claims the benefit of U.S. provisional patent application Ser. No. 60/624,396, filed Nov. 2, 2004, the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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60624396 | Nov 2004 | US |