Nested Lock Mechanism for Hand Tool Handle Fixation

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Solution Overview

Problem

Existing lock mechanisms for hand tools like pliers and crimp tools are either space-consuming, inconvenient to operate, or pose safety risks due to external components.

Innovation Solution

A lock mechanism comprising a latch with a disc and shaft, and a retainer sleeve that allows the latch to switch between positions to detain the handles in either expanded or contracted states, preventing accidental movement and optimizing storage space without additional external components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a snap ring and knob are disposed externally to fix the handles in contracted position, then the handles can be fixed for storage, but additional space is occupied and safety risks may occur

Engineering Contradiction:
Improvehandle fixationVSAvoidtool size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The locking component is nested within the handle structure itself. A protrusion on the first handle fits into a corresponding recess on the second handle, creating an integrated locking mechanism that does not add external components. This nesting approach eliminates the need for separate snap rings and knobs while maintaining the fixation function.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The locking function is merged with the handle structure. The protrusion and recess features are directly formed as part of the handle bodies, combining the structural support and locking functions into a single integrated design. This eliminates additional external components and reduces overall tool volume.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a locking member is pushed and rotated to lock the relative position of handles, then the handles can be fixed, but the operation becomes inconvenient

Engineering Contradiction:
Improvehandle fixationVSAvoidlocking operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism utilizes the natural dynamic movement of the handles during operation. When the handles are squeezed together during use, the protrusion automatically engages with the recess, locking the handles in the contracted position without requiring separate manual locking actions. The mechanism dynamically responds to the handle movement itself.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism is self-actuating through the handle movement. The geometric arrangement of the protrusion and recess causes automatic engagement when the handles are brought together during normal operation, eliminating the need for additional manual steps to activate the locking function.

Inventive Principle:
Principle #25Self-service

3Reliability

If external components are added to prevent handles from leaving contracted position, then storage fixation is achieved, but the tool occupies additional space

Engineering Contradiction:
Improvestorage fixationVSAvoidtool footprint
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The locking features are nested within the existing handle geometry. The protrusion on one handle fits into a recess on the other handle, both features being integrated into the handle bodies themselves. This eliminates the need for external snap rings, knobs, or separate locking components that would increase the tool's footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The handle structure serves multiple functions: it provides the gripping surface for operation, structural support during use, and the locking mechanism for storage. The protrusion and recess features are formed as part of the handle bodies, making the handles multi-functional and eliminating the need for separate dedicated locking components.

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

Data Source

PatentEP3159108B1Lock mechanism and hand tool having the same
Publication Date: 2018.10.10 ROBERT W SULLIVAN DBA SULLSTAR TECH
  • EP3159108B1 patent drawingFigure 1A
  • EP3159108B1 patent drawingFigure 1B
  • EP3159108B1 patent drawingFigure 2A~2B

AI summary

The present invention relates to a lock mechanism for a hand tool having two handles (110,120), which comprises: a latch (131) and a retainer (140) for retaining the latch (131). The latch (131) comprises: a disc (134) and a shaft (132) passing through and fixed with the disc (134). The shaft (132) is coaxial with the disc. The lock mechanism (130) is disposed within the hand tool.