Patent Application
20090059492
This invention relates to a device for use in an environment where flammable gases may be present, and, more particularly to such a device including an exterior housing, with an electrical component and battery inside the housing.
Some devices containing an electrical component have been made of polycarbonate, and polycarbonate is known to have adequate tensile strength and no ability to hold an electrical charge, i.e., it cannot be rubbed with a cloth to create a charge. See U.S. Pat. No. 6,409,942.
Polycarbonate has also been used as a lens for an explosion proof light source is old. See U.S. Pat. Nos. 4,112,485, 4,264,946, 5,534,664, 6,371,625, 6,409,942, and 7,086,283.
In U.S. Pat. No. 4,112,485, it was noted that electric lamps are known in which a light source is placed into a transparent casing and tightly enclosed therein (see German Patent DGM No. 1833690). In other versions, one or several light sources are directly and tightly surrounded with transparent cast polyester or similar material and designated as “explosion-proof” (see British Patent No. 1166442 and U.S. Pat. No. 3,310,670).
None of this prior art addresses how to make a remote control device that can be used in an environment where flammable gases may be present.
U.S. Viebrantz et al. Pat. No. 4,768,230 is directed to a sealed housing for a hand-held remote control transmitter, and U.S. Toth et al. Pat. No. 3,974,933 is directed to an explosion proof and watertight enclosure.
One of the principal objects of the invention is to provide an improved device for use in an environment where flammable gases may be present, which separates and isolates items presenting any explosion risk from those that re regarded as intrinsically safe. This is especially important because of the significant investment in time required to obtain government approvals for changes to such devices. By placing the devices of greatest concern all within an explosion proof interior housing, the ability to improve the device without having to obtain further approvals is presented.
Another of the principal objects of the invention is to provide such a device that solves the problem of how to do this in a handheld device.
The invention thus provides a device for use in an environment where flammable gases may be present, the device including a sealed water proof exterior housing, and an interior explosion proof, sealed housing made of polycarbonate, mounted inside the exterior water proof housing. An electrical component is inside the interior sealed housing, and an intrinsically safe battery is outside of the interior housing but electrically connected to the component inside the interior housing. The battery is also mounted inside the exterior housing.
Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of the construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. Further, it is to be understood that such terms as “forward”, “rearward”, “left”, “right”, “upward” and “downward”, etc., are words of convenience in reference to the drawings and are not to be construed as limiting terms.
As illustrated in
As shown in
More particularly, the exterior housing 14 is made in two separate sections, a polycarbonate top molding 32 and a polycarbonate bottom molding 36, with a seal 37 received between the top and bottom moldings. Sandwiched between the two sections is a structural member 40. The structural member 40 completely separates one side of the device 10 from the other side of the device 10. The structural member 40 is planar and has a back 44 (see
Further, the interior housing 18 is an explosion proof rectangular chamber attached to the structural member 40. More particularly, the interior housing 18 has a base 56, four sides 60, and a top 64. In the preferred embodiment, the base 56 and four sides 60 are formed integrally with the structural member 40, but in other embodiments, they can be separate pieces that are connected and sealed together. The interior housing 18 is totally enclosed and sealed by chemically welding the interior housing top 64 to the edges of the housing four sides 60.
The electrical component 22 inside the interior housing is a radio frequency module 70. Still more particularly, as shown schematically in
The device 10 has an interface between the battery 24 and the electrical component 22, and the interface is inside the interior housing 18. More particularly, an opening 89 into the interior housing 18 through the interior housing top 64 receives a wire 94 extending from the battery carrier assembly 28, before the interior of the interior housing 18 is potted.
More particularly, the device further includes a polycarbonate lens 104 attached to the structural member front 48, so that the LCD screen 88 can be seen outside the housing 14, and a battery compartment area 108 on the structural member back 44 adjacent the interior housing 18. The membrane keypad 52 is connected to the electrical component 22 inside the interior housing 18 via an opening 90 in the front 48 of the structural member 40.
As shown in
Various other features and advantages of the invention will be apparent from the following claims.
