Illumination – Self powered lamp – With movable focusing element
Reexamination Certificate
1999-03-04
2001-02-06
O'Shea, Sandra (Department: 2875)
Illumination
Self powered lamp
With movable focusing element
C362S208000, C362S203000
Reexamination Certificate
active
06183106
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention. This invention relates to flashlight assemblies and, more particularly, to a shock absorbent flashlight assembly.
2. Prior Art. One type of flashlight assembly includes a metal cylindrical battery housing which contains batteries. External threads on one end of the metal cylindrical battery housing are threaded into internal threads at one end of a cylindrical reflector subassembly. A bulb is mounted to a bulb mounting subassembly which axially moves within the reflector subassembly along the axis of the reflector subassembly. A spring mounted in the reflector subassembly biases the bulb mounting subassembly away from the reflector subassembly so that the bulb mounting subassembly contacts the one end of the metal cylindrical battery housing. The axial position of the bulb mounting subassembly within the reflector subassembly is adjusted by screwing the external threads on the one end of the metal cylindrical battery housing into and out of corresponding internal threads in the cylindrical reflector subassembly.
The bulb is mounted to the bulb mounting subassembly by inserting two lead-pins of the bulb into sockets which are pressed fit into the bulb mounting subassembly to provide a voltage from the batteries to the bulb. The reflector subassembly has an axial hole through which the bulb extends. The axial position of the bulb along the axis of the reflector is adjusted by screwing the external threads on the one end of the metal cylindrical battery housing into and out of corresponding internal threads in the cylindrical reflector subassembly. Adjustment of the axial position of the bulb along the axis of the reflector allows adjustment of the focus of the beam of light from the flashlight, as needed.
A severe environment for flashlight assembly such as described above is when it is mounted to a weapon such as a pistol or rifle and is subjected to severe shock and vibration caused primarily by recoil inertial forces produced by rapidly expanding gases generated when a bullet or projectile is fired from the weapon. In the case of an automatic pistol or rifle, another source of shock and vibration is the abrupt movement of the automatic slide-mechanism for ejecting a spent shell or cartridge and reloading an unfired shell or cartridge. This shock and vibration courses both axial and radial displacement of the bulb from the flashlight when a cylindrical coordinate system is used.
The invention is useful for other lighting applications where the flashlight or light source is subject to being dropped or subject to other shock or mechanical vibrations that may break the light bulb or filament.
It has been found that the usual pin-and-socket arrangements described above for mounting the bulb in a flashlight assembly mounted, for example, to a weapon have resulted in failure of the flashlight bulb caused by the glass envelope of the bulb striking the sides of the axial hole in the reflector. The forces caused, for example, by firing the weapon also can misalign the bulb in the sockets so that it is not centered along the axis of the flashlight resulting in an uneven plume of light.
Consequently, a need exists for a technique to reduce shock or vibration induced failures flashlight assembly. A need also exists for keeping a bulb properly aligned within a flashlight assembly.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an improved shock absorbent flashlight assembly which provides reduced shock or vibration induced failures.
It is another object of the invention to provide an improved weapon-mounted shock-absorbent flashlight assembly.
It is a further object of the invention to provide a shock-absorbent flashlight bulb assembly.
In accordance with these and other objects of the invention, an improved shock-resistant flashlight assembly is provided for protecting a flashlight bulb having a cylindrical body and having a base through which pass a pair of lead-pins. The bulb is mounted in a particular way to a cylindrical bulb chassis. The bulb chassis has a pair of pin-sockets on its front end for receiving the lead-pins of the bulb. The pin-sockets have lead contacts which extend through the bulb chassis and out of the rear surface of the bulb chassis to provide electrical connection of the lead-pins of the bulb to opposite terminals of a battery source contained in a battery housing. The base of the light bulb is mounted to the lead chassis such that the base of the light bulb is mounted adjacent to and spaced apart from the top surface of the bulb chassis;
A layer of resilient silicone material is then positioned in the clearance space between the spaced-apart base of the light bulb and the front surface of the bulb chassis to provide cushioning for axial movement and radial movement of the light bulb.
The flashlight assembly includes a cylindrical flashlight reflector housing which has a cylindrical body with a large axial bore formed therein for slideably receiving the cylindrical bulb chassis. A helical spring is contained in the large axial bore of the cylindrical flashlight reflector housing. This spring provides a biasing force which pushes the bulb chassis out of the reflector housing towards the rear of the flashlight. Rotation of the reflector housing with respect to the battery housing moves the bulb along the axis of the flashlight to change the focus of the flashlight beam. The flashlight reflector housing has a radially symmetric concave internal reflective surface formed in its front end around the central axis and a central axial bore is formed in the flashlight reflector housing to provide clearance for the light bulb and to also accommodates movement of the light bulb along the central axis;
An important aspect of the invention is that a heat resistant resilient O-ring is inserted in an enlarged rear portion of the central bore of the reflector housing. This O-ring has an internal surface which engages the cylindrical body of the light bulb such that the O-ring cushions the light bulb for radial movements of the light bulb with respect to the central axis of the reflector housing and so that the light bulb remains mechanically and optically aligned with the central axis. The durometer of the O-ring is between 60-70 and the durometer of the silicone layer between 50-60. The thickness of the O-ring is chosen to be sufficient to absorb shock from the bulb and the O-ring slip fits around the bulb to assure proper mechanical and optical alignment to the central axis of the bulb.
The cylindrical battery housing has external threads formed in one end for engagement with corresponding internal threads formed near the back end of the reflector housing. The cylindrical battery housing is designed to contain one or more batteries and is part of an electrical connection from the battery contact ring to one terminal of the batteries, where the other terminal of the batteries is connected to the battery contact coil spring.
The flashlight assembly further includes a second O-ring with a durometer of 70-80 which extends around the periphery of the rear surface of the bulb chassis to provide cushioning for rearward axial movement of the bulb chassis. A battery contact ring extends around the periphery of the rear surface of the bulb chassis next to and behind the other O-ring. One of the lead contacts of the pin-sockets which extend out of the rear surface of the bulb chassis is fixed to the battery contact ring. A battery contact coil spring extends away from the rear surface of the bulb chassis and the other one of the lead contacts of the pin-sockets is fixed to the battery contact coil spring. An insulated washer is positioned between the battery contact ring and the battery contact coil spring.
An improved flashlight bulb mounting assembly according to the invention includes the flashlight bulb, the heat-resistant O-ring which is around the bulb, the bulb chassis with the pair of pin sockets and their leads, the layer of resilient silicone material between the base of the light bulb and th
Singh Chanchal M.
Szemeredi Robert S.
Thummel Heinz F.
O'Shea Sandra
Sawhney Hargobind S.
Streamlight Inc.
Wagner , Murabito & Hao LLP
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