Clamp Meter Jaw Opening Force Reduction via Dynamic Moment Arm
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Solution Overview
Problem
Earth loop measuring clamps require high jaw opening force to minimize air gaps between contact faces, making them inconvenient for users due to increasing effort as the clamp opens.
Innovation Solution
A reduction device comprising interposed rods between the elastic return element and the trigger, which modifies the moment arm ratio around the pivot axis, reducing the opening force by decreasing the length of the arm of the opposing force as the clamp opens, thus equalizing the application and opposing moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the clamp is designed to require very large jaw opening force to minimize air gap between contact faces, then the closing pressure of the two jaws is improved, but the ease of operation deteriorates due to increasing effort as the clamp opens
Solution Approach 1:
The patent applies a dynamic moment arm mechanism where the moment arm length varies during the opening motion. Initially, the moment arm is long to provide mechanical advantage and reduce opening force. As the jaw opens, the moment arm shortens to increase closing pressure. This dynamic adjustment resolves the contradiction between ease of opening and maintaining high closing pressure throughout the motion range.
Solution Approach 2:
The invention changes the geometric parameter of the moment arm length during operation. By designing the trigger mechanism with a specific pivot point and linkage geometry, the effective moment arm changes from a longer initial value to a shorter final value, thereby transforming the force characteristics dynamically to satisfy both opening ease and closing pressure requirements.
2Device complexity
If the moment arm length is kept constant, then the structure is simpler, but the opening force increases significantly as the clamp opens
Solution Approach 1:
Rather than using a constant moment arm, the patent implements a dynamic moment arm through a carefully designed trigger linkage. The moment arm length varies naturally with the jaw opening angle, providing long moment arm at the start of opening (reducing initial force) and short moment arm at full opening (maximizing closing pressure). This dynamic approach maintains operational ease without significantly complicating the structure.
3Ease of operation
If the moment arm length is increased to reduce opening force, then the ease of operation is improved, but the closing pressure of the jaws decreases
Solution Approach 1:
The patent resolves this contradiction by making the moment arm length dynamic rather than static. The mechanism is designed so that the moment arm is long during the opening phase (reducing required opening force) and becomes short when the jaw reaches the closed position (maximizing closing pressure). This dynamic transformation allows both requirements to be satisfied simultaneously through geometric design of the trigger linkage.
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
Significantly lowers the force required to open and maintain the clamp in an open state while maintaining closing pressure, reducing the effort needed to apply the trigger force by approximately 70% compared to traditional designs.
Implementation Method 1
an elastic element for returning the movable jaw to its closed position
Implementation Method 2
the elastic return element (spring) exerts a restoring force on the movable jaw
Implementation Method 3
A reduction device comprising interposed rods between the elastic return element and the trigger, which modifies the moment arm ratio around the pivot axis, reducing the opening force by decreasing the length of the arm of the opposing force as the clamp opens
Implementation Method 4
the movable jaw being formed by an arm of a lever with two arms, which is pivotally mounted on the fixed support
Data Source
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AI summary
The clamp has a movable jaw (4) mounted on a support to move between a closed position in which end of the jaw is urged to contact with end of fixed jaw (2) and an open position. A traction spring (R) urges the movable jaw to the closed position. The movable jaw is located on an arm (7) of lever (6), and another arm forms a control trigger (5) to pivot the lever between the positions. A device (16) for scaling-down pressure force (Fap) applied to the trigger to open the clamp relative to force maintaining the jaw in the open position. The device is mounted between the spring and the trigger.