Patent Application
20070232459
The invention relates to an improved leg brace for a stilt, particularly stilts employed in the construction industry to facilitate overhead work, such as accessing and hanging suspended ceiling structures or overhead electrical or duct work.
U.S. Pat. No. 5,645,515, the disclosure of which is incorporated by reference herein, is an example of one type of stilt employed by the construction industry. It utilizes a single upright post extending above the shoe platform and having a calf brace near the upper end to provide stability to the user. The calf brace attaches to the side of the post and is solely dependent on the retention of the fasteners for safety.
The calf brace in this disclosure is constructed of metal and is expensive to produce. A calf brace that could be produced in one step would be less labor intensive and less expensive.
Also, metallic calf braces are subject to fatigue cracks over time, and are not easy to straighten if bent by accident or abuse. Constructing the braces out of a material that resists fatigue and damage would enhance their durability.
Also, the calf brace in both of these disclosures presents an inherent safety hazard during falls because of its metallic construction. A brace construction less likely to result in a cut during a fall would be very desirable.
Further, additional redundancy against failure of the stilt due to loss of the brace retaining bolts would be desirable.
The object of the invention is to provide an improved leg brace for a stilt that, in preferred embodiments, overcomes the above noted deficiencies.
One embodiment of the invention is provided in the form of a non-metallic unitary leg brace element for a stilt. The leg brace element comprises a plastic body. The plastic body defines a generally semi-cylindrical concave inside surface for supporting a stilt user's leg, and a passage spaced apart from the generally semi-cylindrical concave inside surface for receiving a leg support of the stilt.
Prior art stilt leg braces were formed of metal from expensive extrusion and bending processes. They were subject to metal fatigue, stress cracking, and possible failure when in use. They were also lacking in comfort for the user, sharp edged and heavy, and presented an additional injury hazard for users during falls. The inventive stilt leg brace is cheaper to produce, more durable, more comfortable, and safer than metallic stilt leg braces according to the prior art.
With reference to
A wide range of plastic material is suitable for construction of the brace element 2. For cost and speed of production, a thermoplastic would be preferred. For strength, a fiber reinforced thermoplastic would be preferred. For durability, an engineering thermoplastic would be preferred. Short glass fiber reinforced polyetheretherketone (PEEK) is a suitable material, for example. The brace element 2 is preferably produced by an injection molding process.
The generally semi-cylindrical concave inside surface is positioned around a longitudinal axis 8. A longitudinal axis 10 of the passage is generally parallel to the longitudinal axis 8.
The brace element can be described as comprising a first portion 12 and a second portion 14. The portion is a generally saddle-shaped structure having an inner surface which defines the generally cylindrical inside surface and an outer surface 16. The second portion protrudes from the outer surface of the first portion and is longitudinally elongated and defines the passage.
The second portion is positioned between first half of the outer surface of the first portion and a second half of the outer surface of the first portion. The outer surface of the first portion has an upper end and a lower end. The second portion preferably comprises an upper ear element 18 protruding from the upper end of the outer surface of the first portion, and a lower ear element 20 protruding from the lower end of the outer surface of the first portion. A tubular element 22 extends between the upper ear element and the lower ear element and defines a portion of the passage. Preferably, an upper end of the passage is closed by a portion 24 of the upper ear element.
The passage is preferably configured to closely accept the upper end of the stilt upright on which it will be positioned. A circular cross section is preferred for uprights constructed of round tubing.
The second portion preferably further defines at least one transverse borehole 26 in communication with the passage suitable for receiving a fastener to fasten the non-metallic unitary leg brace element to a stilt leg support received by the passage. Pins fitted with a retention device or bolts with nuts and a locking mechanism would be suitable. In the illustrated embodiment, the upper ear defines a first transverse borehole and the lower ear defines a second transverse borehole. Each of the boreholes is in communication with the passage and is suitable for receiving a fastener to fasten the non-metallic unitary leg brace element to a stilt leg support received by the passage.
Preferably, the first portion further defines outwardly protruding reinforcing bands extending circumferentially from the upper ear and the lower ear. In the illustrated embodiment, an upper band 28 is positioned adjacent to the upper end of the outer surface of the first portion and a lower band 30 is positioned adjacent to the lower end of the outer surface of the first portion. The first portion has a first lateral end 32 and a second lateral end 34 and further defines a first bridge structure 36 connecting the upper band to the lower band near the first lateral end and a second bridge structure 38 connecting the upper band to the lower band near the second lateral end. The tubular element is spaced apart from the outer surface of the first portion to define a passage 40. The brace element defines a location for receipt of a user safety strap 42 between the upper and lower reinforcing bands and extending between the tubular element and the first and second bridge structures and the outer surface of the first portion. A layer 44 of cushioning is further positioned on the generally cylindrical inside surface in the preferred embodiment. Foam fastened with adhesive is suitable.
While certain preferred embodiments of the invention have been described herein, the invention is not to be construed as being so limited, except to the extent that such limitations are found in the claims.
