Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Impact driven fastener – e.g. – nail – spike – tack – etc. – Including integral locking means
Patent
1991-11-01
1993-07-27
Lindsey, Rodney M.
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Impact driven fastener, e.g., nail, spike, tack, etc.
Including integral locking means
411456, 411487, F16B 1508
Patent
active
052305970
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a fastener and in particular relates to a fastener especially suitable for use in post and rail construction for cattle yards, fences and the like.
BACKGROUND OF THE INVENTION
Post and rail construction is widely used in a plethora of applications, including fencing, framing and scaffolding. The fasteners used for securing the generally vertical posts to generally horizontal rails have for the most part been the traditional coach bolt and nut, threaded rods with a nut both ends and other well known fixings.
In the art of post and rail fencing, it is known that wire tying, notching and strapping may be used in addition to the abovementioned prior art fixings.
Where coach bolts or threaded rods are proposed to be used for post and rail construction, the post and/or the rail is generally checked, notched or recessed to ensure positive location of the two members. The post and the rail are offered up or aligned and then drilled to provide a continuous hole for passage of the bolt or rod. The bolt or rod is then inserted through the hole to effect a joint between the post and rail. Subsequently washer(s) are fitted as required.
A disadvantage of this form of construction includes the protrusion of the bolt or threaded rod on both sides of the joint. In the case where threaded rods are used this protrusion is of a quite hazardous nature, the exposed threaded end of the rod being capable of inflicting injury to both personnel and livestock.
A second disadvantage lies in the requirement for a precise diameter hole to be drilled, large enough to ensure passage of the shank of the bolt, but not so large that the joint is sloppy.
Where wire tying is proposed, the last mentioned disadvantage is substantially overcome. However wire tying is labour intensive, involving the procedure of providing at least two holes drilled through both members, threading the tie wire through the holes and around a keeper and then crimping the disengaged ends under tension. The wire tied joint is also prone to loosening over time; since there is no provision for retightening a wire tie, the ongoing maintenance involves periodic replacement of the ties with the attendant high labour cost.
Loosening of the joint is also a problem for top rails secured to the top of posts by strapping. The strapping is generally affixed to opposed locations of the post by nailing. Although strapping is quick to instal and does not require the drilling of holes it has the added disadvantages of hazard wherein after a period of time the strap edge may extend or turn outwardly with the ancillary effect of nail loosening. It is also impossible to tension such strapping, resulting in a loose rail. To obtain the best possible result in strapping a top rail, it is desirable to V-notch the top of the post to accept the rail, which procedure is time consuming.
Upon a review of relevant prior art, it is clear that it is well known to provide barbs or protrusions on shanks or fasteners to resist withdrawal of the fastener from a workpiece. Thus for example in U.S. Pat. No. 4,653,486 there is described a fastener particularly suited for orthopedic use having a head, a tip, and a shank having a thread bearing zone and a thread free zone. The thread bearing zone includes a plurality of spaced barbs forming a discontinuous screw thread. Each protrusion in one embodiment was of uniform height not possessing a clearly defined leading edge and trailing edge and in another embodiment each protrusion had a leading arcuate surface again not possessing a clearly defined leading edge and trailing edge. One disadvantage of the particular fastener if used in post and rail construction was that it possessed limited holding strength by virtue of the fact that it would cut its own withdrawal track when forced into a wooden substrate and thus was relatively easily withdrawable. This fastener was also not appropriate for use with predrilled holes.
Similar comments could be made in relation to U.S. Pat. No. 3,983,779 which describes a sheet metal nail having a
REFERENCES:
patent: 791442 (1905-06-01), Anderton
patent: 1444618 (1923-02-01), Levingston
patent: 1619944 (1927-03-01), Leonard
patent: 1638671 (1927-08-01), Wagner
patent: 2528685 (1950-11-01), Brown
patent: 3494006 (1970-02-01), Brumlik
patent: 4420918 (1983-12-01), Arnoux et al.
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