Rear Handle Mounting Assembly for Vibration Damping

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Solution Overview

Problem

Hammer drills generate significant vibrations during operation, which are transferred to the rear handle and can cause discomfort and injury to the operator, especially during prolonged use.

Innovation Solution

A mounting assembly for the rear handle that includes a sliding upper mounting mechanism with a helical spring and a pivoting lower mounting mechanism, utilizing a metal rod and pin with bellows to absorb and dampen vibrations, reducing the transfer of vibrations from the hammer drill body to the handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rear handle is rigidly mounted to the body, then the structural stability is improved, but the vibration transmission to the handle increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidvibration transmission
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The mounting assembly incorporates movable mounting mechanisms that enable relative movement between the rear handle and the body. The upper mounting mechanism allows sliding movement along a guide, while the lower mounting mechanism permits pivoting movement. This dynamic configuration reduces vibration transmission by allowing the handle to move independently from the body, absorbing vibratory forces while maintaining structural integrity during operation.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a vibration dampening mechanism is introduced, then the vibration transmission is reduced, but the device complexity increases

Engineering Contradiction:
Improvevibration transmissionVSAvoidmounting assembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The mounting assembly is divided into distinct upper and lower mounting mechanisms, each performing a specific function. The upper mechanism handles sliding movement and primary vibration dampening, while the lower mechanism handles pivoting movement and secondary vibration reduction. This segmentation allows for modular design, easier manufacturing, and maintenance, while effectively reducing vibration transmission through coordinated action of the separate components.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If the rear handle is moveably mounted, then the vibration dampening is improved, but the structural stability deteriorates

Engineering Contradiction:
Improvevibration dampeningVSAvoidstructural stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The movable mounting mechanisms are designed to provide vibration dampening while maintaining operational stability. The guide in the upper mechanism and the pivot point in the lower mechanism constrain the handle's movement to specific degrees of freedom, allowing vibration absorption without compromising the structural connection between the handle and body during actual use.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mounting assembly acts as an intermediary element between the rigid body and the handle. It provides a controlled interface that allows relative movement for vibration dampening while maintaining a stable functional connection. The guide and pivot mechanisms serve as intermediaries that translate vibratory movements into controlled motions, preserving structural stability while reducing harmful vibrations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively reduces the transmission of vibrations to the rear handle, minimizing operator discomfort and the risk of injury by absorbing and damping vibrations in multiple directions, thereby enhancing user safety and comfort during extended use.

Implementation Method 1

a helical spring which enables the rod to slide within the passageway and which biases the rod in a direction away from the front of the hammer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The lower mounting mechanism comprises a pin which passes through a hollow passage in a projection from the rear housing, and a set of bellows

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2898991B1Rear handle
Publication Date: 2018.12.26 BLACK & DECKER CORP
  • EP2898991B1 patent drawingFigure 1
  • EP2898991B1 patent drawingFigure 2
  • EP2898991B1 patent drawingFigure 3~4

AI summary

A power tool comprising: a housing (2); a handle (24) having two ends, the first end (30) being moveably mounted to the housing (2) via a first mounting assembly (34), the second end (32) being moveably mounted to the housing (2) via a second mounting assembly (36); a biasing mechanism (242) connected between the housing (2) and the handle (24); wherein at least one of the mounting assemblies (36, 34) comprises: a first part mounted on the housing (2) and a second part mounted on the one end (32) of the handle (24), one part comprising a support (74), the other part comprising a pin (70), having a longitudinal axis (290), located in the support (74) which is capable of being rotated in the support (74) to enable the end (32) of the handle (24) to rotate relative to the housing (2) and to move linearly in the support (74) to enable the end (32) of the handle (24) to move linearly relative to the housing (2); wherein the support (74) comprises a passage (266) in which the pin (70) is located; wherein the passage has a cross section which is substantially uniform in shape along the length of the passage (266), which cross section has a shape with a larger length (268) in a first direction and a smaller width (270) in a second perpendicular direction, the pin (70) being capable of freely moving within the passage (76) either rotationally about its axis (290) to enable the end (32) of the handle to rotate relative to the housing (2) or linearly in a direction of the larger length (268) to enable the end (32) of the handle to move linearly relative to the housing (2); characterised in that the size of the smaller width (270) varies along the length of the passage (266) to provide at least one curve convex surface (272) along at least part of the length of the passage (266) which is capable of being engaged by the side of the pin (70) to enable the pin (70) to pivot within the passage about an axis parallel to the direction of the larger length.