Fire escape – ladder – or scaffold – Traversing – track-mounted
Reexamination Certificate
2000-04-27
2002-12-03
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Traversing, track-mounted
C104S111000, C104S093000, C104S112000
Reexamination Certificate
active
06488118
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to a safety apparatus which moves along a cable and serves as a support for a safety line or the like, and more particularly, to an improved fall arrest bypass device which may ride freely on a flexible and/or rigid cable without being impeded by cable supports intervally located along the cable.
Workers who perform tasks at heights on elevated or suspended platforms, and workers who operate near vertical edges need to be protected from falls that could cause injury or death. In fact, the U.S. government has established the Occupational Safety and Health Administration (“OSHA”) to regulate employers having workers who perform job tasks in these types of environments. Under regulations enacted by OSHA, each employee must be protected by a safety system when walking or working on a surface higher than six feet above the ground or a lower level.
This safety system may be a fall arrest system which arrests an employee in a short distance following a fall from a working level. A conventional fall arrest system consists of an anchorage point, a harness, and a mechanism connecting the harness to the anchorage point. It may also include a lanyard, deceleration device, lifeline, or suitable combination of these elements. A personal fall arrest system must limit the maximum arresting force on an employee to 1800 pounds, and be rigged so that an employee cannot fall more than six feet or come in to contact with any lower level. The fall arrest system must also be constructed to have sufficient strength to withstand twice the potential impact energy of a free-fall of six feet or the stopping distance provided by the system, whichever is less.
Fall arrest systems which are presently in use are typically attached to a single fixed anchor point. A worker is connected to the fixed anchor point by a lanyard attached to a harness or safety belt worn by the worker. This single fixed anchor system is a safe option for performing tasks in a limited area, but many tasks require the worker to move over a larger area. In the latter situation, the worker must disconnect the lanyard from the fixed anchor point and reconnect it to another fixed anchor point. During the change-over time, the worker is in danger of falling, which could result in serious injury or death. As a result, the single fixed anchor point system severely limits the type of tasks a worker can safely and legally perform.
Other safety systems exist that provide more mobility than the single fixed anchor point system. For example, in a track system, a lanyard is attached at one end to the worker via a harness, and to a trolley, slide, or other movable component on the other end. The trolley, slide, or other movable component is adapted to move freely along a conventional track, which can be an I-beam, a metal or plastic rail, or a cable that is either supported at various points along a work path or is anchored safely at its two end points. The supports function to both hold the track in place and to support the weight of the trolley and one or more workers in the event of a fall. The track is usually directly overhead in relation to the worker's position, and can curve around corners or incline at angles. Some tracks such as I-beams require permanent installation.
Tracks like that described above typically require numerous supports which present an obstacle to conventional track-type fall arrest devices. A worker using a conventional fall arrest device must disconnect the device from the track between each support. Again, this places the worker in danger of falling. Additionally, these devices create wear on the track as well as the fall arrest device itself, which may result in frequent and costly replacement of parts.
Many tasks could be made easier and would benefit from a hands free fall arrest device that can pass freely over or through the track supports unaided by human intervention and unimpeded by undue frictional orientation of passing components. Designs of track-traveling and fall arrest devices that permit movement of a device past a plurality of local track supports are known. U.S. Pat. No. 304,730, to High, describes a truck that rides upon a gas-pipe track to move a fire escape ladder around a building. The truck disclosed by the High patent has two independent yokes, each with a carrying wheel adapted for the track. A gate is located on the rear side of the truck, and is hinged to the truck with a fulcrum-pin to allow the truck to pass through brackets that support the track. The truck described by the High patent is bulky and heavy, which prevents its use as a fall arrest device. Furthermore, these types of trucks are expensive to manufacture due to the redundant components that may be necessary to support an off-balance fire escape ladder, but are not necessary to support workers or other objects.
U.S. Pat. No. 5,979,599, to Noles, describes another track-traveling apparatus that rides upon a cable safety track which is supported by a plurality of supports. Noles discloses a track-traveling element with a single pulley that can ride upon the cable safety track. The track-traveling element has a slot which allows the element to pass over the brackets which support the cable. However, the track-traveling element disclosed by Noles cannot be removed from the cable safety track without severing the track or disengaging the track from its source. The permanence of the track-traveling element will cause it to be exposed to environmental conditions that could cause wear and corrosion, and prevents the track-traveling element from being easily removed and stored for later use.
To overcome the problems and disadvantages associated with the prior art, it is an objective of the improved bypass device of the present invention that it be strong enough to withstand the force of a falling object connected to the device. Furthermore, the bypass device should also be attached to a cable in a manner sufficient to hold a worker in case of a fall.
It is another objective that the improved bypass device of the present invention be capable of riding freely along a cable and passing over one or more support brackets without having to be removed from the track. The bypass device should also be able to ride freely around corners and curves of the track without having to be removed.
It is a further objective that the improved bypass device of the present invention be securely attached to the cable to prevent accidental disengagement that would place the worker in a dangerous situation. However, the improved bypass device of the present invention should also have a mechanism to easily remove it from the track so that the bypass device may be stored when not in use.
Another objective of the bypass device of the present invention is that it be lightweight with easily replaceable parts, and that it can be adapted to fit different size cables. The bypass device should ride freely on the cable without encountering significant friction, thereby preventing wear on the bypass device itself, as well as preventing the bypass device from causing any degree of wear to the support cable.
Finally, it is also an objective of the improved bypass device of the present invention that all of the aforesaid advantages and objectives be achieved without incurring any substantial relative disadvantage.
SUMMARY OF THE INVENTION
The disadvantages and limitations of the background art discussed above are overcome by the improved fall arrest bypass device which is taught by the present invention.
The bypass device is a component of a safety system which will meet and exceed applicable standards the government (OSHA) requires to protect workers having job duties at hazardous heights. The bypass device is attached at one end to a cable, and at the other end to a safety line extending to a harness of a worker. The safety line can be a rope lanyard, a retractable cable, webbing, or other types of lines known by those skilled in the art. The cable is engineered to support one or
Chin-Shue Alvin
Reinhart Boerner Van Deuren S.C.
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