Twist Grip Throttle Assembly for Precise Weed Trimmer Speed Control
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Solution Overview
Problem
Prior art weed trimmers face issues with fine motor speed adjustment due to short plastic trigger travel, vulnerability to damage during transport, operator fatigue from trigger configuration, and difficult throttle cable replacement.
Innovation Solution
A twist grip throttle assembly replaces the traditional trigger, featuring a rotatably mounted tubular throttle activator with vibration-dampening ridges, allowing for sensitive power control and a natural operator position, and enabling easy conversion of existing trimmers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional plastic trigger is used for throttle control, then the device structure is simple, but fine motor speed adjustment is difficult due to short trigger travel
Solution Approach 1:
The patent inverts the traditional trigger pressing motion into a rotary twisting motion. Instead of pushing a trigger forward along a short linear path, the user rotates the grip assembly, converting linear throttle control into rotational control. This inversion provides unlimited angular travel for fine adjustments while maintaining structural simplicity through the use of the existing grip assembly as the control interface.
Solution Approach 2:
The patent transitions from one-dimensional linear trigger movement to two-dimensional rotational movement. The throttle control is achieved through rotation around the grip axis, adding an angular dimension to the control mechanism. This dimensional change enables continuous fine adjustment of motor speed throughout the entire rotation range, overcoming the limited travel of traditional triggers.
2Reliability
If a traditional plastic trigger is used, then manufacturing is simple, but the trigger is vulnerable to damage during transport
Solution Approach 1:
The patent makes the grip assembly serve multiple functions: it provides the user interface for holding the tool and simultaneously serves as the throttle control mechanism through rotational movement. By integrating the throttle control function into the existing grip structure rather than adding a separate fragile trigger component, the design eliminates vulnerability to trigger damage while maintaining manufacturing simplicity.
Solution Approach 2:
The grip assembly performs dual duties: it is both the structural handle for operator comfort and the functional throttle control interface. The rotational movement of the grip itself activates the throttle cable, eliminating the need for a separate trigger mechanism that could be damaged during transport.
3Ease of operation
If a traditional trigger configuration is used, then the structure is simple, but operator fatigue occurs due to awkward hand and arm position
Solution Approach 1:
The patent merges the support handle and throttle control functions into a single integrated grip assembly. The rotational throttle control is incorporated directly into the handle structure, allowing the operator to maintain a natural gripping position while controlling motor speed. This integration eliminates the need for separate trigger mechanisms that require awkward hand positions.
4Adaptability or versatility
If a traditional trigger assembly is used, then cable replacement might be easier, but fine motor speed adjustment is difficult and the trigger is vulnerable to damage
Solution Approach 1:
The patent inverts the control mechanism from linear trigger pressing to rotational grip twisting. This inversion provides continuous rotational travel for precise motor speed adjustment while simplifying the overall assembly by using the grip structure itself as the control interface rather than adding a complex trigger mechanism.
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 twist grip throttle assembly provides improved motor speed control sensitivity, reduces operator fatigue, and simplifies cable replacement, while maintaining a natural user position and providing vibration dampening.
Implementation Method 1
A grip having vibration dampening ridges is preferably received on the gripping area of the throttle activator
Data Source
AI summary
A twist grip throttle assembly and weed trimmer utilizing the same are described herein. The weed trimmer has a power head on an upper end of a drive shaft assembly. The power head has a power provider, such as a gas powered motor. A base assembly with a cutter head for receiving wrapped cord is on a lower end of the drive shaft assembly. A throttle activator includes a tubular member rotationally mounted on the drive shaft assembly. The tubular member defines a gripping area. Twisting rotation of the throttle activator adjusts an amount of power produced by said power provider.