Reverse Marked Fish Tape for Remaining Length Measurement

Solution Overview

Problem

Existing fish tapes with ascending unit measurement markings make it difficult to determine the remaining length of the tape on the reel, especially when used as a consumable item or when snagged inside conduits, leading to wastage and inefficiency in cable installations.

Innovation Solution

A fish tape with reverse markings, where the leading end has the highest unit measurement and the innermost end is the starting point, allowing easy measurement of the remaining tape length without full unwinding, enabling it to be used as a consumable item while maintaining accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ascending unit measurement markings are used on the fish tape, then the tape can be used as a consumable item and cut to length, but it becomes difficult to determine the remaining tape length when snagged or partially used

Engineering Contradiction:

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent inverts the conventional marking sequence on the fish tape. Instead of ascending markings (0 at the inner end, highest number at the leading end), the tape uses descending markings (highest number at the inner end near the reel, 0 at the leading end). This inversion allows the user to immediately see how much tape has been paid out by reading the marking at the leading end, solving the problem of determining remaining length when the tape is snagged or partially used.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If the fish tape is fully unwound to determine remaining length, then accurate measurement is possible, but time and productivity are reduced

Engineering Contradiction:

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The fish tape markings are designed to be self-indicating. The descending marking sequence allows the tape to automatically display the remaining length information through its own markings without requiring external measurement tools or actions. The user simply reads the marking at the leading end to determine remaining length, eliminating the need to fully unwind or use separate measuring devices.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent extracts the measurement function from a separate process (fully unwinding the tape to measure) and integrates it directly into the tape's markings. By placing the highest number marking at the inner end and descending toward the leading end, the measurement information is continuously available on the tape itself during installation, eliminating the need for a separate measurement step.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If the fish tape is not marked with measurements, then the structure remains simple, but the ability to measure conduit length and determine cable requirements is lost

Engineering Contradiction:

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies reverse sequencing to the measurement markings. Conventional tapes ascend from 0 at the start to the highest number at the end. This invention inverts that sequence, placing the highest number at the inner end (near the reel) and descending to 0 at the leading end. This simple reversal provides accurate measurement capability while maintaining minimal structural complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS8899554B2Reverse marked fish tape

Publication Date: 2014.12.02

AI summary

The fish tape includes a measuring scale. The tape is scaled from zero to a number equal to the length of the tape. The numbers incrementally increase from the tapes proximal end to the tapes distal end.