Illumination – Revolving
Reexamination Certificate
2001-03-01
2002-10-08
O'Shea, Sandra (Department: 2875)
Illumination
Revolving
C362S286000
Reexamination Certificate
active
06461009
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to rotating warning lights intended primarily for installation on land and marine vehicles and particularly to a modular rotatable warning light sub-assembly which can be readily customized for use in conjunction with a variety of warning light systems. Additionally, this invention is directed to a modular rotatable warning light having enhanced durability and ease of manufacture, installation and maintenance.
2. Description of the Related Art
Warning light assemblies in the form of light bars mounted on emergency vehicles are well known in the art. Light bars typically employ several light sources. The light sources may be constant or pulsating. There are two basic types of light sources capable of generating a pulsating or flash pattern. These two different types of pulsed light sources consist of light sources employing gaseous discharge tubes or high-intensity incandescent lamps under electronic control and mechanically driven, i.e., rotating or oscillating light sources. The mechanically driven warning lights may employ a rotating or oscillating reflector carrying a light source. A more practical prior art arrangement moves the reflector around a stationary light source. The light source and reflector cooperate with one or more stationary lenses to produce a pulsating light pattern. Design specifications resulting from user requirements or the end-use environment dictate the particular type of pulsed light generator that is to be used in a warning light system.
There has been a trend toward customization and flexibility in the design and manufacture of warning light systems for use in conjunction with emergency vehicles. This trend has been driven primarily by customer demand for improvements in the visibility, durability and overall performance of warning light systems. Additionally, warning light systems are mounted to an increasing variety of vehicles for use in various air, sea and land environments. Increased customization has resulted in a proliferation of rotatable warning light subassemblies, each appropriate for a particular application. To satisfy the need for multiple versions of a rotatable warning light, engineers have increasingly employed molded plastic components for the constituent parts of these assemblies.
Typically, a rotatable warning light assembly includes a base configured to mount to the vehicle or light bar, a stationary lamp holder mounted to the base and a rotatable sub-assembly including a reflector mount and a reflector. The sub-assembly is arranged to rotate the reflector around a stationary lamp when driven by a direct current motor. When energized, the lamp is constantly lit and the sub-assembly is rotatably driven around the stationary lamp to produce a pulsed light pattern.
The rotatable sub-assembly is typically constructed of molded plastic parts consisting of a stationary hub surrounded by a rotatable reflector mount including an external gear wheel. The lamp and its associated electrical connections remain stationary within the hub. Rotational freedom between the reflector mount and stationary hub is enhanced by using a single row of spaced ball bearings that travel in races molded into the hub and lens mount, respectively.
Warning light systems attached to emergency vehicles are frequently exposed to the most severe environmental conditions involving physical shock, vibration and large swings in temperature, from well above 100° F. to well below 0° F. Because of exposure to large temperature differentials, tolerances within the rotatable warning light assembly must be adjusted to accommodate material expansion and contraction. The warning light assembly may also be subjected to moisture, salt, sand and windblown dust. The plastic from which the hub and reflector mount are vulnerable to wear in these harsh environments. A combination of loose tolerances and wear frequently results in poor performance and premature failure in rotatable warning light assemblies. The proliferation of rotatable warning light designs requires manufacturers and service organizations to maintain a large inventory of rotatable subassemblies to keep warning light systems for emergency vehicles operational and minimize down time.
There is a need in the art for a heavy duty, standardized rotatable sub-assembly having a compact and efficient configuration suitable for use in a variety of rotating warning light arrangements.
There is also a need for a standardized rotatable sub-assembly having significantly enhanced capability to withstand physical shock and temperature swings while having smooth and reliable rotation over a long service life.
SUMMARY OF THE INVENTION
Briefly stated, the invention in one preferred form comprises several standardized components, including a shaft, rotatable sub-assembly, motor and drive train for use in a variety of rotatable warning light assemblies. The rotatable sub-assembly includes a reflector mount supported for rotation around a hub by two axially spaced bearings, thereby providing a more stable, durable and smoother running rotatable sub-assembly in a compact and efficient configuration. The reflector mount includes a worm wheel having gear teeth compatible with a motor driven worm gear.
The shaft, hub, reflector mount, motor and worm gear form the core of a modular warning light assembly. Various base plates, lamp holders, lamps and reflectors can be used in conjunction with the standardized core components to produce a variety of customized rotatable warning light assemblies. Standardized core components allow the manufacturer and service organizations to reduce inventories.
An object of the present invention is to provide a new and improved rotatable sub-assembly for a rotatable warning light where the sub-assembly is compatible with a wide variety of warning light configurations.
Another object of the present invention is to provide a new and improved rotatable warning light assembly including a heavy duty rotatable sub-assembly having improved durability and a more efficient and smooth operation.
REFERENCES:
patent: 4701743 (1987-10-01), Pearlman et al.
patent: 5339224 (1994-08-01), Woehler
Alix Yale & Ristas, LLP
O'Shea Sandra
Truong Bao
Whelen Engineering Company, Incorporated
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