Pole Saw Harness with Spring-Loaded Balancer
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Solution Overview
Problem
Hand-held power tools for tree care and hedge trimming, when used at angles between 10 to 105 degrees from a vertical plane, impose a large load on the operator's arms, making extended working periods uncomfortable and potentially harmful.
Innovation Solution
A harness with a tool balancer system featuring a strap wound on a rotatable reel and a spring, with fairleads on the power tool to distribute the weight, allowing the strap to be attached to a rear portion of the harness, and adjustable fairleads to balance the tool's weight effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the power tool has a lifting eye located substantially at the center of gravity to balance the weight, then the weight balance is improved, but the distance to the rear grip becomes too long resulting in an uncomfortable working position
Solution Approach 1:
A strap is introduced as an intermediary element connecting the power tool to the operator's harness. The strap attaches to the pole at a point forward of the center of gravity and extends backward to the operator's back, serving as a mediator that transfers the tool's weight to the operator's torso rather than requiring the operator's arms to support the full weight. This resolves the contradiction by providing weight support without compromising the gripping position.
Solution Approach 2:
The suspension system transitions from a vertical single-point suspension (at the center of gravity) to a distributed suspension system that extends in multiple dimensions. The strap connects forward of the center of gravity on the pole and extends backward to the operator's harness, creating a diagonal support arrangement that distributes weight across both the tool's structure and the operator's body in different spatial dimensions.
2Adaptability or versatility
If the operator holds the tool at angles of 10 to 105 degrees from a vertical plane, then the working flexibility is improved, but the load on the arms becomes very large making extended working periods impossible
Solution Approach 1:
The strap acts as a mediator that transfers the gravitational load from the power tool directly to the operator's harness system. By attaching the strap forward of the center of gravity and extending it backward to the operator's back, the system allows the operator to maintain various working angles while the strap supports the tool's weight, preventing the arms from bearing the full load during extended periods.
3Device complexity
If a single point suspension is used, then the device complexity is reduced, but the operator comfort and weight distribution are insufficient
Solution Approach 1:
The suspension system is segmented into multiple functional components: a strap element, an attachment point on the pole, and connection points on the operator's harness. By segmenting the suspension function across these separate elements rather than using a single complex mechanism, the system achieves improved weight distribution and operator comfort while maintaining relative simplicity in each individual component.
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
This setup reduces the load on the operator's arms, enabling extended working periods without discomfort or harm, by distributing the tool's weight through two points rather than a single point, thus improving operator comfort and safety.
Implementation Method 1
a spring, at least indirectly connected to the strap for balancing the weight of the power tool
Implementation Method 2
for balancing the weight of the power tool
Data Source
AI summary
A harness (10) for reducing the load on the arms of operator working with a pole saw or pole hedge trimmer at operating positions at angles particularly between 10 to 105 degrees from a vertical line, in which the power tool (1) is suspended in a strap (31) extending from a front portion (12) of the harness (10), through at least one fairlead (6) provided on the power tool (1) and to a rear portion (11) of the harness (10). The strap (31) is included in a tool balancer (30), which includes a spring loaded reel (32) for the strap (31) and is attached to or preferably integrated with a chest plate/buckle (14) in the harness (10), and which permits locking of the reel (32). The at least one fairlead (6) includes a hook (8) for easy hooking of the power tool (1) onto the strap (31) and unhooking of the same therefrom.