Measuring and testing – Specimen stress or strain – or testing by stress or strain... – By loading of specimen
Reexamination Certificate
2000-09-29
2003-05-06
Williams, Hezron (Department: 2855)
Measuring and testing
Specimen stress or strain, or testing by stress or strain...
By loading of specimen
C073S856000
Reexamination Certificate
active
06557420
ABSTRACT:
TECHNICAL FIELD
This invention relates in general to a testing safety apparatus, and more specifically to a device for testing the structural integrity of safety hand rail structures.
BACKGROUND OF THE INVENTION
In any industrial setting, safety is a prime concern. It is important to ensure that the safety devices installed to protect workers and others on a job site perform as designed, and also comply with any applicable safety regulations such as those issued by the Occupational Safety and Health Administration (OSHA), and in the case of offshore vessels the U.S. Coast Guard and the American Bureau of Shipping (ABS). It is also important to ensure that the devices continue to perform as designed throughout their life span. One way to ensure that the safety devices are functioning properly is to test the devices both after manufacture and periodically during use.
When workers and others have access to a raised area, it is sensible to equip the area with hand rails to prevent a possible fall. Additionally, regulatory agencies, such as OSHA, require that fall protection, such as a hand rail, be present in most situations where a worker could fall six feet or more, and sets out strength requirements for the hand rails. While hand rails can be designed to safely support a worker and meet the regulatory standards, it is possible that the finally constructed hand rail could not meet the criteria because of defects in the manufacturing. Therefore, to ensure a safe hand rail and regulatory compliance, it is desirable to test the hand rail upon installation.
Hand rails are often subject to adverse environmental conditions such as salt, sun, and sometimes corrosive chemicals which may deteriorate the strength of an otherwise adequate design. Additionally, the hand rails are sometimes abused and subject to unanticipated loads and impact loads which may damage the railing. To ensure the hand rails remain safe and are adequate for the intended purpose, it is desirable to periodically test the hand rails in service and after any repairs.
Testing the hand rail on site, as discussed above, presents several difficulties which must be overcome to make a hand rail testing apparatus practical. Although some minimum dimensions for hand rails are regulated, hand rails are built in many shapes and from many different material cross-sections. Therefore, a hand rail testing apparatus should be able to accommodate as many hand rail configurations as possible. Many times a worker must carry the hand rail testing apparatus a significant distance, and up stairs and ladders. Additionally, most hand rails are located in confined areas, where space for using the handrail testing apparatus is limited. Thus, a hand rail testing apparatus should be light weight to minimize the strain imposed on the worker when transporting the testing apparatus. Also, a hand rail testing apparatus should be relatively compact, so that it may be used in tight quarters. Finally, it is helpful that the hand rail testing apparatus be easy and inexpensive to construct, so that multiple testing apparatus can be used at different sites.
One device for testing the strength of a hand rail both after installation and periodically is disclosed in U.K. Patent Number GB 2,091,888. This device wedges between the railing and an adjacent structure, and expands with a hydraulic cylinder to load the hand rail. The hydraulic pressure is then measured to determine the loading. This device is functional, but the hydraulic cylinder adds significantly to its weight, and an integral dolly, disclosed in the patent, is required to maneuver the device. This makes it more difficult to transport the device from site to site. Additionally, a solid adjacent structure is required to test the railing, and therefore the disclosed device is not suitable for testing all hand rails. Finally, the inclusion of hydraulics increases the cost of the disclosed testing apparatus because it necessitates the expense of a devoted hydraulic cylinder, gauge, and hydraulic fittings.
Therefore, there is a need for a portable hand rail testing apparatus that has universal applicability to many hand rail installations. Since it is desirable to test the hand rails once installed, the device should be light weight and maneuverable, so that it can be easily transported to the hand rail location. The testing apparatus must be compact to allow testing of handrails in confined areas, and it should also be simple and inexpensive to build, so that many testing devices can be built.
SUMMARY OF THE INVENTION
The present invention is directed towards an inexpensive, portable hand rail testing apparatus with universal applicability to many hand rail installations. The invention is an apparatus for testing the structural integrity of a hand rail structure. The hand rail has a plurality of horizontal parallel rail members. The apparatus includes an elongate lever arm wit h a mounting portion on the lever arm sized to span at least two rail members. A receptacle on the mounting portion opposite the lever arm receives one of the rail members and vertically supports the lever arm and mounting portion. A vertical force applied to the lever arm is transmitted to the hand rail.
Further, the apparatus has a force measuring device on the lever arm. The force is applied through the force measuring device. The force measuring device may be a torque wrench. The mounting portion is on a distal end of the lever arm and the force measuring device is on a proximal end of the lever arm. A second receptacle is on the mounting portion positioned to receive a second parallel rail member. The second receptacle is moveable relative to the first mentioned receptacle. The first mentioned receptacle supports the lever arm and mounting portion when the force is applied in a first vertical direction. The second receptacle supports the lever arm and mounting portion when the force is applied in a second vertical direction. The receptacle can be removed and replaced with a different receptacle.
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ISR, PCT/US 01/42376; Mar. 25, 2002 Date Mailed.
Safety Alert No. 189; Guardrails; U.S. Department of the Interior Mineral Management Service Gulf of Mexico OCS Region; Published Jul. 19, 2000.
Garcia Romeo E.
Lanclos Michael
Ensco International Incorporated
Jenkens & Gilchrist P.C.
Martir Lilybett
Williams Hezron
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