Rack-Pinion String Gripper Transmission for Racket Stringing

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Solution Overview

Problem

Existing pulling string apparatuses for stringing machines suffer from friction and wear issues in their transmission mechanisms, leading to inaccurate tension measurement and reduced lifespan due to the use of screws and nuts, which affects the stringing process in racket sports.

Innovation Solution

A pulling string apparatus with a transmission mechanism comprising a sliding block, transmission rack, and drive gear, where the sliding block is mounted on guide rods with linear bearings to reduce friction, and a control circuit to manage the drive element based on sensor feedback, ensuring precise tensioning and loosening of racket strings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a screw and nut transmission mechanism is used in the pulling string apparatus, then the string gripper and sensor can move back and forth under motor control, but friction is created between the screw and nut causing wear and tear of parts over time

Engineering Contradiction:

Improvelinear reciprocating motion controlVSAvoidpart wear and lifespan

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces the screw-nut mechanical transmission system with a rack-pinion mechanism. The pinion gear engages with the rack to convert rotational motion into linear reciprocating motion of the string gripper and sensor assembly, eliminating the friction and wear problems inherent in screw-nut connections while maintaining precise motor-controlled movement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If a screw and nut transmission mechanism is used, then the string gripper and sensor can be driven by the motor, but the friction creates wear that deviates the tension measured by the sensor

Engineering Contradiction:

Improvestring tensioning functionVSAvoidtension measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent substitutes the screw-nut transmission with a rack-pinion system that eliminates friction-induced wear. This ensures that the sensor measures tension accurately without deviation caused by mechanical wear, while still enabling the motor to drive the string tensioning function effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a screw and nut transmission mechanism is used, then the string gripper can move back and forth, but long-term use causes wear that influences the accuracy of stringing

Engineering Contradiction:

Improvereciprocating motion capabilityVSAvoidstringing accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces the wear-prone screw-nut mechanism with a rack-pinion transmission system. This substitution maintains the ability of the string gripper to move back and forth for string tensioning while eliminating the friction wear that would otherwise accumulate over time and affect stringing accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly reduces friction and extends the lifespan of the apparatus, providing accurate force measurement and improved string tension control, thus enhancing the stringing process for racket sports.

Implementation Method 1

A plurality of linear bearings are arranged in the guide holes for the sliding block to connect with slide along the guide rods, which considerably reduces the friction between the sliding block and the guide rods.

Methodology Applied

Scientific EffectFriction reduction through linear bearings: Lubrication

Implementation Method 2

the drive gear is connected to the output shaft of the drive element and is engaged with the transmission rack

Methodology Applied

Scientific EffectGear engagement and mechanical transmission: Gear

Implementation Method 3

the drive gear is connected to the output shaft of the drive element and is engaged with the transmission rack, the sliding block is arranged on the transmission rack

Methodology Applied

Scientific EffectRack and pinion mechanism: Rack and Pinion

Data Source

PatentUS11305162B2Pulling string apparatus of stringing machine

Publication Date: 2022.04.19 GUANGZHOU MASTRIPOD TECH LTD

AI summary

A pulling string apparatus of a stringing machine comprising a string gripper, a sensor, a drive element, a transmission mechanism and a control circuit; the sensor is connected with the string gripper to detect the pull force of the string gripper; the control circuit compares the detected pull force value with a pre-set value, and control the rotation of the drive element; the transmission mechanism comprises a mounting base, a sliding block, a transmission rack and a drive gear; wherein the drive gear is connected to the drive element and is engaged with the transmission rack, the sliding block arranged on the transmission rack is connected with the sensor; when the sensor and the string gripper are driven forward or backward by the sliding block under the act of the transmission rack engaged with the drive gear, the racket string will be tensioned or loosened.