Rotatable Catch Lever for Adjustable Pliers

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Solution Overview

Problem

Conventional adjustable pliers face challenges in securely holding and easily releasing the arm positions, requiring users to keep a button pressed during both jaw-closing and jaw-opening actions, making them inconvenient to use, especially when wearing gloves or handling pipes of varying diameters.

Innovation Solution

The adjustable pliers incorporate a rotatable catch with two extreme positions and an inclined tooth arrangement in the longitudinal slot, allowing the displaceable active arm to slide over the passive arm with ease, enabling quick jaw adjustments without needing to constantly rotate the lever, facilitated by a radial lever accessible with the thumb.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a button mechanism is used to release the spindle, then the jaw opening can be adjusted, but the user must keep the button depressed during both jaw-closing and jaw-opening actions, making it inconvenient to use

Engineering Contradiction:
Improvejaw opening adjustmentVSAvoidconvenience of use
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The invention transforms the static button-pressing mechanism into a dynamic lever-based locking system. The lever can be rotated to locked and unlocked positions, automatically maintaining the jaw opening without requiring continuous user input during operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lever mechanism automatically maintains the jaw opening once set, eliminating the need for continuous button depression. The system serves itself by maintaining the locked position through the lever's mechanical engagement with the toothed rack.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If a stepped arrangement is used to vary the jaw opening, then the distance between jaws can be modified, but the security of firmly holding the arms in position is compromised

Engineering Contradiction:
Improvejaw spacing modificationVSAvoidposition holding security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention uses a toothed rack with inclined teeth rather than simple stepped holes. The inclined geometry of the teeth provides mechanical advantage and self-locking capability, ensuring secure positioning while allowing smooth adjustment between multiple discrete positions.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The lever mechanism is designed to engage with the toothed rack before final positioning is achieved. The gradual engagement of the lever with the inclined teeth provides progressive locking, ensuring secure holding from the outset rather than relying on final-position accuracy alone.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If internal sliding of arms is achieved by disengaging a spindle, then jaw regulation is possible, but the mechanism becomes complex and time-consuming to operate

Engineering Contradiction:
Improvejaw regulation capabilityVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The lever serves multiple functions: it acts as a locking mechanism when engaged with the toothed rack, and as a release mechanism when rotated to disengage. This multi-functionality eliminates the need for separate buttons or complex control systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the locking, positioning, and release functions into a single lever mechanism. The lever's rotation simultaneously controls engagement with the toothed rack and release of the spindle, simplifying the overall mechanism compared to separate control systems.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2596912B1Lever mechanism for adjustable pliers
Publication Date: 2015.02.25 SNA EURO INDS
  • EP2596912B1 patent drawingFigure 1
  • EP2596912B1 patent drawingFigure 2~3
  • EP2596912B1 patent drawingFigure 4~5

AI summary

The invention relates to a lever mechanism for adjustable pliers (1), of a kind which has a displaceable active arm (2) having a transverse recess with two flanks (2a) between which there is located a passive arm (3) which has a longitudinal slot (4) provided with at least one inclined tooth arrangement (4a), there being fixed to the displaceable active arm (2) a displaceable spindle (6) which slides along the longitudinal slot (4), characterised in that said displaceable spindle (6) has an engaging configuration of a shape corresponding to a non-circular engaged orifice (5a) of a rotatable catch (5) which has, on one side, a catching tooth arrangement (5b) facing the inclined tooth arrangement (4a) of the longitudinal slot (4), and the rotatable catch (5) has, on the opposite side, a resilient spring (8); the displaceable spindle (6) has, in its upper part, a radial lever (7) located in the proximity of the thumb of the user.