Wire Guide Device for LB Fitting
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Solution Overview
Problem
Existing devices for guiding wires through conduit fittings, such as LB fittings, require a second electrician and often cause damage to the wire due to sharp edges or insufficient roller sizes, especially when dealing with optical fiber cables.
Innovation Solution
A wire guiding device with two rollers, one for pulling around the angle and another to prevent contact with edges, mounted within a frame adaptable to LB fittings using removable axles and fasteners, allowing for adjustment and easy removal after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single electrician pulls wire through an LB fitting without a guide device, then the operation is simpler, but the wire contacts sharp edges causing damage
Solution Approach 1:
The patent introduces a guide device as an intermediary between the wire and the sharp edges of the LB fitting. This device includes rollers mounted on a frame that can be temporarily attached to the fitting, allowing the wire to pass through without direct contact with harmful edges, thus protecting the wire while enabling single-electrician operation
Solution Approach 2:
The guide device is segmented into removable components: a frame with holes for fastener attachment, and separately mounted rollers with axles. This segmentation allows the device to be temporarily assembled, used, and then disassembled and removed, leaving no permanent attachments on the fitting
2Volume of moving object
If a small roller is used to guide wire through a fitting, then the device size is reduced, but the wire may still be damaged by bending around the small radius
Solution Approach 1:
The patent applies parameter changes by specifying that the rollers must have a minimum diameter sufficient to prevent wire damage. The roller diameter is changed from the small size used in prior art to a larger size that maintains the wire's structural integrity during pulling, particularly important for optical fiber cables with glass fibers
3Reliability
If a guide device is permanently attached to the fitting, then wire guidance is improved, but the fitting cannot be covered with a standard cover
Solution Approach 1:
The guide device transitions from a static permanent attachment to a dynamic temporary attachment. The frame includes holes that receive fasteners which can be inserted and removed, allowing the device to be attached during wire pulling and then detached to allow standard covers to be affixed to the fitting
Solution Approach 2:
The guide device is designed to be discarded after use - the fasteners are removed, the frame is taken off the fitting, and the rollers are removed from the frame. This allows the fitting to return to its original state and be covered with standard covers, while the guide device components can be recovered and reused elsewhere
Data Source
AI summary
A wire guiding device for use with an electrical fitting such as an “LB” fitting is provided. The wire pulling device comprises a frame and two rollers mounted on axles. A first roller allows a wire to be pulled around the angle of the fitting and may be of sufficient diameter to prevent damage to the wire, while a second roller may prevent the wire from contacting the damaging edges of the fitting. The rollers are mounted within a frame which is adaptable to the access port of an LB fitting. Holes may be located in the frame such that fasteners engage the pre-existing threaded holes located in a standard LB fitting.