Static structures (e.g. – buildings) – Mechanism operated relatively movable shaft assembly – Tilts relative to base
Reexamination Certificate
2000-08-01
2002-11-26
Horton, Yvonne M. (Department: 3635)
Static structures (e.g., buildings)
Mechanism operated relatively movable shaft assembly
Tilts relative to base
C052S028000, C052S110000, C052S121000, C362S259000, C362S385000, C362S386000, C362S419000
Reexamination Certificate
active
06484456
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a telescoping mast assembly useful in sundry applications and, more specifically, to a telescoping mast assembly suitable for mobile field use.
2. The Prior Art
Telescoping masts are well known safety devices useful in law enforcement, industrial, military or commercial applications. Such masts are portable devices which can be readily deployed when needed and readily returned to a storage position when not in use. Typical applications are those in which equipment or devices require elevation in order to optimally accomplish their intended function. It may be desirable, or essential, to elevate floodlights, cameras, antennas, or other surveillance equipment by means of a telescopic mast assembly in order for such devices to function optimally. By way of example, one common application is to mount a telescopic light mast upon the roof of a vehicle for illuminating a wide area surrounding the vehicle. The mast must quickly and reliably deploy when necessary, and retract against the roof of the vehicle when not in use. Law enforcement officials, in particular, have found such devices useful in the field.
Heretofore, telescoping masts have been either pneumatically, hydraulically, or chain driven. Pneumatic drive motors require airtight seals between telescopic mast sections in order to function as intended. However, the environment in which such masts are used makes maintaining an airtight condition between mast sections problematic. Contaminants, or radial ice, deposited between mast sections, or at the junction will stop the mast from descending or cause damage to the mast sections, and can easily destroy the seal required for efficient operation of the pneumatic drive. In the event that the pneumatic integrity of the seal is destroyed, the mast will fall due to gravity with a potential for disastrous consequences.
A further disadvantage to pneumatically powered telescoping masts is that they can only assume one of two positions. Either the masts are fully extended or fully retracted. In many applications, however, because of obstructions or other considerations, it is desirable to, have the telescoping mast sections in a partial state of extension or retraction. A further disadvantage with pneumatic drives is that they are relatively heavy in weight, limiting their suitability for vehicle roof applications. In addition, such drives are expensive to manufacture, assemble, and maintain, which limits their commercial appeal.
Finally, in applications where the unit is used on uneven terrain, pneumatic units cannot work consistently on grades exceeding fifteen degrees and, if the loading at the top is high, even less. The tubes on pneumatic masts on slopes exceeding the limit may bend at the joint, causing air leakage at the junction and a corresponding failure. A unit accordingly is needed which can safely maintain structural integrity on slopes exceeding fifteen degrees.
Hydraulic systems for elevating masts suffer from many of the same shortcomings. Hydraulic drives are relatively heavy in weight and are expensive to manufacture, assemble, and maintain. Moreover, such drives are vulnerable to damage from contact with the environment since hydraulic lines are exposed. Additionally, contaminants can infiltrate the hydraulic system and cause malfunction or failure.
Chain driven telescopic masts likewise suffer from the same deficiencies. The drive mechanisms are relatively heavy in weight and are expensive to manufacture, assemble,, and maintain. The chain link mechanism is also exposed and susceptible to damage from contact with environmental objects.
Other shortcomings common to the aforementioned conventional telescopic mast drives and devices are that the wiring to the outboard end of the mast is exposed and can be damaged by inadvertent contact with surrounding obstacles or suffer from damage from exposure to the elements. Moreover, the masts are generally fabricated from conductive material from the base to the top end. An electrical charge introduced into such masts from inadvertent contact with exposed overhead electrical lines will, accordingly, be transferred to the vehicle below, causing a potential for danger to the operators on the ground. Available systems lack effective means for preventing such a charge transfer, such as a fuse system. However, even were fuses implemented into wiring of available units, because the wiring is exposed to the elements, such fuses would be prone to damage and deterioration from exposure to the elements and may not function as intended when they are needed. A further shortcoming to conventional telescopic mast systems is that their relative large physical size makes mounting such assemblies to vehicle rooftops cumbersome. Since the roofs of contemporary cars and trucks are comparatively small by historical measure, a mast system of a more compact design and configuration than those available currently is needed. Moreover, telescoping masts often must share the roof surface of police or emergency vehicles with other devices such as a horizontal light bar. The presence of a light bar reduces the surface area available for mounting a telescoping light mast assembly. A need, accordingly, exists for a light mast assembly which occupies a relatively small surface area of a rooftop and which is compatible with other devices such as a horizontal light bar on the roof of a vehicle.
Telescoping masts, heretofore, have been employed primarily as a stand alone rooftop units for the purpose of elevating an illumination device to a higher position in order to enlarge the illuminated field. Such light masts are not deployed when the vehicle is in motion because they cannot withstand wind sheer forces generated impinging upon a moving vehicle. Rather, the light masts can only be deployed when the vehicle is stationary. This restriction on the use of telescoping masts is a significant deficiency and prevents the use of telescoping mast-mounted equipment in a myriad of circumstances where such equipment would be useful. There is, according, a need for a telescoping mast system which can be used in mobile circumstances and withstand the wind forces impacting against a moving vehicle.
A further deficiency in state of the art telescopic masts is that they heretofore have only found application in supporting illumination devices. No available vehicle mounted mast systems provide the capability for elevating radar detection devices; video or audio equipment; strobe lighting; digital signage, or other types of safety equipment. There is, accordingly a long felt need for a safety system comprising a telescoping mast capable of supporting and elevating a diverse range of safety equipment, including audio speakers; radar/laser speed detection devices; emergency lighting; video surveillance equipment; and/or digital warning signage. Such equipment, while operational at a rooftop level, would benefit functionally from placement at a higher elevation. A further need is for a mast system that can support such equipment while the vehicle is in motion. A police vehicle, by way of example, would find it advantageous to elevate, actuate, and operate speed detection, video, audio, or digital warning signage equipment while the vehicle is in motion.
There is a further safety benefit to relocating audio, video, detection, and other types of equipment from the interior of a vehicle to a rooftop location. Heretofore audio, video, and speed detection equipment have been positioned within the passenger compartment of a police or emergency vehicle on the dashboard, seat, or floor, within reach and visual line of sight of the driver. Such a location not only does not place the equipment in an optimal high elevation, but also tends to result in an undesirably cluttered internal compartment of the vehicle proximate to the driver. The clutter created by placing such equipment in close proximity to the driver results not only in discomforte for the driver, but can pose a safety risk by co
Cooper Bryan L.
Davis Kevan A.
Featherstone Harry
Featherstone Teamed Industries, Inc.
Horton Yvonne M.
O'Planick Richard B.
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