In-line strainer with tension control mechanisms for use on high tensile wire

Abstract

An in-line strainer for placement within a span of wire fence to apply tension thereto is provided. The in-line strainer includes a reel having a hollow central hub for receiving a torque limiting mechanism. The torque limiting mechanism includes a central axle and a spring mechanism. As the axle is manually rotated, the reel is also rotated through its engagement with the torque limiting mechanism until a target tension on the wire is reached. Once the target tension has been reached, the torque limiting mechanism disengages, allowing the axle to “slip” relative to the reel, preventing further rotation of the reel and, consequently, further tensioning of the wire. In addition, the in-line strainer includes a failure mechanism which ensures that, when the load threshold on the fence is exceeded, the in-line strainer will automatically release tension on the wire wound thereon in a predictable and safe manner.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention is related to wire fencing and, more particularly, to a device for controlling maximum tension during installation of high tensile wire fence and for providing a predictable release mechanism when tension overload occurs.[0003]2. Description of the Related Art[0004]When installing high tensile wire fence, such as for livestock, it is necessary to place a specified amount of tension on the wire. Typically, this tension is applied after the wire has been strung around a fence perimeter by installing an in-line strainer at spaced locations along spans of fencing. A representative conventional in-line strainer installed on a wire extending between two fence posts is shown in FIG. 1. The use of in-line strainers to tension wire fencing is well known in the art.[0005]A commonly recommended pre-load for high tensile fences is 250 lb of tension. To set the pre-tension of the wire, existing in-line strainer...

AI Technical Summary

Benefits of technology

[0011]Accordingly, it is an object of the present invention to provide an in-line strainer that overcomes the difficulties encountered with prior art devices when trying to achieve an accurate pre-load on high tensile fences, the present invention including a reel with a torque limiting mechanism that prevents the wire from being tensioned beyond the desired pre-tension level.

[0013]A further object of the present invention is to provide an in-line strainer in accordance with the preceding objects in which the reel has external teeth that are engaged by a pawl to keep the reel from unwinding, the pawl having a failure mechanism that ensures that the in-line strainer will break in a predictable and safe manner when tension on the wire exceeds maximum safe load.

[0017]Another object of the present invention is to provide an in-line strainer in accordance with the preceding objects that is not complex in structure and which can be manufactured at low cost but yet effectively prevents wire fencing from being tensioned beyond a desired pre-tension during installation and, during use, provides for safe and predictable failure when maximum safe load on the fence wire is exceeded.

Problems solved by technology

However, “reading” the spring is often a matter of interpretation, leaving the installer uncertain as to whether the correct pre-tension level has been reached.

The manner in which the failure occurs after maximum load has been exceeded is unpredictable and random, which can result in injury to the person installing the fence or other collateral damage, as significantly tensioned parts of the strainer and / or the fence wire are suddenly released to effectively act as high-speed projectiles.

Similarly, even if the fence wire is properly tensioned, over-tensioning can occur during use, such as by a livestock-imposed load on the fence, which again results in unpredictable and random forms of wire and / or tensioning mechanism failure.

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