Patent Publication Number: US-3876851-A

Title: Sealed mounting for pushbutton switch

Description:
United States Patent [191 McMains et al.  
 [ Apr. 8, 1975 [75] Inventors: Billy D. McMains, Garden Grove;  
 Carl E. l-lilsabeck, Fountain Valley,  
 both of Calif.  
 [73] Assignee: Jay-El Products Incorporated,  
 Gardena, Calif.  
 [22] Filed: Jan. 11, 1974 [211 Appl. No.: 432,453  
 [52] US. Cl 200/302; 200/340 [SI] Int. Cl. H0lh 13/06 [58] Field of Search.... 200/302. 340. 159 R, 159 B;  
 277/2l2 F, 2l2 C, 212 PB [56] References Cited UNITED STATES PATENTS 2,357,973 9/1944 Robbins 200/302 2.984.726 5/196] Roeser 200/302 Amis et al 200/302 Tobey et al 200/302 Primary Examiner-Robert K. Schaefer Assistant E.\&#39;aminerWilliam J. Smith Attorney, Agent, or Firm-Christie, Parker &amp; Hale [57] ABSTRACT A sealed assembly for a front-mounting pushbutton switch in a panel. A flexible annular diaphragm has a single convolution, with a rigid ring bonded to the outer portion of the diaphragm and the inner portion of the diaphragm bonded to the pushbutton of the switch. The outer portion of the diaphragm has projecting ridges which are compressed against the inside of a tubular seal adapter by pressing the ring into the adapter. The adapter engages an opening in the panel. The switch housing is in turn supported by the adapter on the panel to hold the switch in place.  
 7 Claims, 1 Drawing Figure SEALED MOUNTING FOR PUSI-IBUTTON SWITCH FIELD OF THE INVENTION This invention relates to pushbutton switches, and more particularly, to a mounting and sealing assembly for pushbutton-actuated switch.  
 BACKGROUND OF THE INVENTION The use of pushbutton switches mounted on an instrument panel is well known. Frequently such switches include a light source for back-lighting the face of the pushbutton to illuminate a legend identifying the function and status of an electrical circuit controlled by the pushbutton switch. Under certain environmental conditions, it is desirable that the interior switch parts be sealed against moisture, dust or other materials which might invade the interior parts of the switch and cause damage or malfunction. To effectively seal the movable pushbutton presents a problem. It has been the practice heretofore to provide a flexible membrane which entirely covers the front of the pushbutton switch and is clamped to the surrounding panel to provide a fluidtight cover. The membrane must be made of material sufficiently transparent so as to permit the illuminated legend on the face of the pushbutton to be read through the cover. It has proved difficult in the past to find suitable materials which combine the resilience, flexibility, transparency and other characteristics necessary to achieve satisfactory results with this type of seal. Other types of sealing arrangements have utilized sliding seals which permit the pushbutton to move relative to the mounting while sealing against the intrusion of moisture or other foreign materials into the switch past the pushbutton. Such known arrangements have either been too expensive or unreliable in operation to be effective.  
 SUMMARY OF THE INVENTION The present invention is directed to an improved assembly for mounting a pushbutton switch on a panel and providing a seal between the movable pushbutton and the panel to provide a barrier or seal against the entrance of foreign matter into the interior of the switch housing around the edge of the movable pushbutton. This is accomplished by providing a seal adapter member which is tubular in shape and is inserted in the opening in the panel, the adapter having an outer flange which engages the panel around the periphery of the opening to hold the adapter in place. The pushbutton switch is inserted through the tubular adapter with the pushbutton projecting out of the tubular adapter beyond the face of the panel. An annular sealing member is provided between the inside of the adapter and the sides of the pushbutton member of the switch which includes a flexible convoluted diaphragm bonded at its inner opening to the outside of the pushbutton. The outer perimeter of the flexible diaphragm is clamped against the inside of the tubular adapter by a rigid ring which is pressed into the outer end of the tubular adapter, the ring compressing the flexible material of the convoluted diaphragm against the inner wall of the tubular adapter member to form a frictional seal with the inside of the adapter.  
 DESCRIPTION OF THE DRAWING For a more complete understanding of the invention reference should be made to the accompanying drawing wherein the single figure is a fragmentary sectional view of the mounting and sealing assembly for a pushbutton switch according to the present invention.  
 DETAILED DESCRIPTION Referring to the drawing in detail, the numeral 10 indicates a mounting panel through which is formed an opening 12 for receiving a conventional pushbutton switch assembly indicated generally at 14. While the drawing shows only the left-hand portion of the switch, it will be understood that the switch is symmetrical about a central vertical axis. The opening 12 and the switch assembly may be circular or square in outline about the central axis. The pushbutton switch 14 includes an outer projecting actuating knob 16 having an illuminated face 18. The face 18 is illuminated by a backlight (not shown) within the pushbutton switch 14 in a manner well known in the art. The projecting knob 16 is secured to a stem or actuating member 20 that extends telescopically down inside a switch housing 22 to operate the switch.  
  In the standard pushbutton switch 14, the housing 22 is provided with a projecting bezel 24 which normally is designed to engage the panel around the outside of the opening. In the modified mounting and sealing arrangement of the present invention, the housing 22 is inserted through an opening 26 formed by the bottom 28 of a cup-shaped seal adapter member indicated generally at 30, the bezel 24 engaging the inside of the adapter. The adapter member includes a tubular portion 32 extending from the bottom 28 to an upper outer flange or lip 34. The tubular portion 32 of the cupshaped adapter member 30 is inserted through the opening 12 in the mounting panel 10 with the outer lip 34 engaging the perimeter of the opening 12. A suitable annular gasket 36 may be provided between the face of the panel 10 and the flange 34 to form an effective seal between the adapter member 30 and the face of the mounting panel 10.  
  The pushbutton switch 14 and the seal adapter member 30 are locked in place within the mounting panel 10 by a seal adapter clamp having a base 40 and four upwardly projecting arms, two of which are indicated at 42 and 44 respectively. The four upward projecting arms engage the back of the mounting panel 10 at points surrounding the opening 12 at four sides of the switch assembly 14. The base 40 has an opening 46 through which the inner end of the switch housing 22 is inserted.  
  A tubular mounting sleeve 48 fits over and around the switch housing 22 and acts as a spacer between the clamp member 38 and switch retaining fingers, one of which is indicated at 50. The fingers 50 are tightened against the lower end of the sleeve 48 by screws 52 which are threaded into the lower end 53 of the switch housing 22. Tightening of the screws 52 puts the housing 22 in tension while putting the sleeve 48 and adapter clamp 38 in compression. This causes the mounting panel 10 to be securely held between clamp member 38 and the upper flange 34 of the seal adapter 30 when fully assembled.  
  Sealing of the movable stem 20 of the pushbuttom switch 14 is accomplished by a single convoluted sealing diaphragm 54. The diaphragm 54, which is annular in shape, is molded of silicone rubber or similar flexible resilient material. The diaphragm 54 has an inner portion 56 which is bonded directly to the underside of the knob 16 and the outside perimeter of the stem 20. The  
 diaphragm 54 is formed with a single convolution 58 terminating in an outer portion 60. A plurality of sealing ridges 62 are formed on the outer surface of the outer portion 60 extending around the full outer perimeter of the annular-shaped diaphragm 54. The ridges 62 frictionally engage the inner surface of the tubular portion 32 of the seal adapter member 30. A rigid annular sealing ring 64 is bonded or otherwise attached to the inside of the outer portion 60 of the diaphragm 54 and is provided with a lip or flange 66 which engages the top of the seal adapter 30.  
  When mounting the switch 14 in the panel 10, the switch is first inserted into the seal adapter member 30. This is done by dropping the housing 22 through the opening 26 in the adapter 30. The upper end 60 of the diaphragm 54 is formed slightly larger in perimeter than the inside of the tubular member 32. The upper portion 60 must be forced into the seal adapter 30 by pushing downwardly on the lip 66 of the ring 64. A tapered surface 68 wedges against the inside of the opening formed by the tubular portion 32, deforming the material of the diaphragm sufficiently to compress the diaphragm inside the cup-shaped adapter 30. The resilient diaphragm material is also placed in compression between the inner wall of the adapter 30 and the rigid ring 64, causing the ridges 62 to be flattened and pressed firmly against the inside surface of the tubular portion 32 of the seal adapter 30, thereby providing an effective barrier against the intrusion of any moisture or other material into the switch.  
  The sealing diaphragm 54 in no way interferes with the actuation of the pushbutton switch or the viewing of the backlighted display on the face 18 of the switch. When actuated to its fully depressed position, the pushbutton knob 16 moves inwardly inside the ring 65 to the position indicated by the broken lines, the convolution 58 permitting the inner portion 56 of the diaphragm to move freely downwardly with the pushbutton 16. Since there are no rubbing surfaces, the diaphragm imposes a minimum amount of restriction on the actuation of the pushbutton switch. At the same time, the seal in no way interferes with the viewing of a message or other legend displayed on the face of the pushbutton.  
 What is claimed is:  
 1 1. Apparatus for panel mounting a pushbutton switch having a housing and a pushbutton movable supported by the housing, comprising an annular flexible seal member having an inner opening, the inner opening of the seal member being attached to the pushbutton of the switch and movable therewith, an adapter member having a tubular portion with an outwardly projecting flange at one end, and an inwardly projecting flange at the other end, the pushbutton switch housing being insertable through the adapter member and having projecting stop portions engaging the inwardly projecting flange to limit the extent the housing is inserted into the adapter member, the panel having an opening for receiving the adapter member, the outer flange of the adapter member having a larger perimeter than the opening to limit the distance the adapter member is inserted into the opening in the panel, and clamping means engaging the panel and the pushbutton switch housing for clamping the switch, adapter member, and panel together, the seal member having outer portions engaging the interior of the tubular portion of the adapter member in fluid tight relationship.  
 t lll IlHIH l 4 2.Apparatus of claim 1 wherein the seal member includes a rigid ring adapted to fit inside the tubular portion of the adapter member to hold the seal member tightly against the inside of the tubular portion of the adapter member.  
  3. Apparatus for mounting a pushbutton switch, having a housing and a movable pushbutton projecting from the housing, to a panel having an opening therein, comprising a cup-shaped adapter having a tubular side portion with a projecting lip at one end, the adapter being insertable in the panel opening with the lip engaging the panel surface adjacent the opening, the adapter having an opening at the other end of the tubular portion that is substantially smaller in perimeter than the inside of the tubular portion, the housing of the switch being inserted through the tubular portion and said opening with the pushbutton projecting outwardly through the tubular portion of the adapter, the inside of the tubular portion of the adapter and the outside of the pushbutton forming an annular space, and a sealing member including an annular convoluted diaphragm of resilient flexible material positioned in said annular space, the diaphragm having an inner portion surrounding the pushbutton and in fluid-tight engagement with the sides of the pushbutton, the diaphram further having an outer portion in fluid-tight engagement with the inside of the tubular portion of the adapter, the diaphragm having a convolution between the inner and outer portions to permit unrestricted axial movement of the inner portion relative to the outer portion with movement of the pushbutton.  
  4. Apparatus of claim 3 wherein the sealing member further includes a rigid retaining ring of smaller perimeter than the inside of said tubular portion of the adapter, the outer portion of the diaphram being compressed between the ring and the tubular portion to provide frictional sealing engagement between the diaphragm and the adapter.  
  5. Apparatus of claim 4 wherein the inner portion of the diaphragm is bonded to the pushbutton and the outer portion is bonded to the ring.  
  6. Apparatus of claim 5 wherein the outer portion of the diaphragm is formed with a plurality of ridges to increase the frictional seal with tubular portion of the adapter.  
  7. Apparatus for mounting a pushbutton switch, having a housing and a movable pushbutton projecting from the housing, to a panel having an opening therein, comprising an adapter having a tubular side portion with a projection lip at one end, the adapter being insertable in the panel opening with the lip engaging thepanel surface adjacent the opening, the housing of the switch being supported by the adapter with the pushbutton projecting outwardly through the tubular portion, the inside of the tubular portion of the adapter and the outside of the pushbutton forming an annular space, and a sealing member including an annular convoluted diaphragm of resilient flexible material positioned in said annular space, the diaphragm having an inner portion surrounding the pushbutton and in fluidtight engagement with the sides of the pushbutton, the diaphragm further having an outer portion in fluid-tight engagement with the inside of the tubular portion of the adapter, the diaphragm having a convolution between the inner and outer portions to permit unrestricted axial movement of the inner portion relative to the outer portion with movement of the pushbutton.