Angle Impact Tool Conical Spring Hammer Biasing

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Solution Overview

Problem

Existing angle impact tools lack efficient mechanisms to deliver impact loads while maintaining compact designs, as they often require larger components that hinder their ability to fit into small spaces without compromising torque.

Innovation Solution

The integration of a conical spring between the hammer and the drive gear in the angle impact tool, which biases the hammer away from the drive gear, allowing for a more compact design while maintaining effective impact delivery through a gear assembly including a bevel gear set, spur gear set, and planetary gear set.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a compact design is implemented to fit into small spaces, then the tool can access confined areas, but the torque delivery capability may be compromised

Engineering Contradiction:
Improvetool sizeVSAvoidtorque delivery
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent implements a nested gear assembly where a planetary gear set is positioned inside a hollow cylindrical housing that contains a bevel gear set. This nested configuration allows multiple gear mechanisms to occupy the same spatial envelope, significantly reducing the overall tool size while maintaining the torque multiplication capability through combined gear ratios.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs a dynamic impact mechanism where a hammer rotates about a second axis perpendicular to the motor axis, periodically delivering impact loads to an anvil. This dynamic impact mechanism, combined with the elastic element (spring or rubber material), allows the system to generate high instantaneous torque through impact forces rather than relying solely on steady-state gear torque, thereby maintaining torque delivery in a compact form factor.

Inventive Principle:
Principle #15Dynamics

2Length of moving object

If the overall height of the tool is reduced for better maneuverability, then the tool fits into smaller spaces, but the impact mechanism may require more space to function effectively

Engineering Contradiction:
Improvetool heightVSAvoidimpact mechanism space
Core Design Contradiction:
Length of moving objectVSVolume of moving object

Solution Approach 1:

The patent reorients the impact mechanism by changing the axis of rotation of the hammer from the motor axis (first axis) to a perpendicular axis (second axis). This dimensional change allows the impact mechanism to operate in a different spatial plane, effectively reducing the tool's height while maintaining the functional space required for the hammer and anvil to deliver impact loads.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The planetary gear set is nested within the hollow cylindrical housing that contains the bevel gear set, creating a compact, multi-layered gear arrangement. This nested configuration minimizes the axial space required for the gear train, thereby reducing the overall tool height while preserving the torque transmission path to the impact mechanism.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Volume of moving object

If a conical spring is used to bias the hammer away from the drive gear, then the design becomes more compact, but the complexity of the spring mechanism increases

Engineering Contradiction:
Improvetool sizeVSAvoidspring mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent employs a conical spring instead of a conventional cylindrical spring, changing the geometric parameter of the spring from uniform diameter to tapered diameter. This parameter change allows the spring to exert the necessary biasing force on the hammer while occupying less axial space, thereby reducing tool size. The conical geometry provides a progressive spring rate that can be optimized for the specific impact mechanism requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic element (conical spring or rubber material) acts as an intermediary between the drive gear and the hammer, providing the necessary biasing force to keep the hammer engaged with the drive gear during rotation. This intermediary component enables compact design by eliminating the need for larger mechanical biasing mechanisms while maintaining reliable impact delivery through controlled engagement.

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

This configuration enhances the tool's ability to fit into smaller spaces while maintaining or improving torque delivery, potentially extending the service life and reducing the overall height of the tool, thus addressing the need for a more compact and efficient impact mechanism.

Implementation Method 1

a conical spring positioned between the hammer and the drive gear, the conical spring biasing the hammer away from the drive gear

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2777882B1Angle impact tool
Publication Date: 2018.12.05 INGERSOLL RAND CO
  • EP2777882B1 patent drawingFigure 1
  • EP2777882B1 patent drawingFigure 2
  • EP2777882B1 patent drawingFigure 3

AI summary

Illustrative embodiments of angle impact tools are disclosed. In at least one illustrative embodiment, an angle impact tool (10) may comprise a motor (16) including an output shaft (40) configured to rotate about a first axis (42), an impact mechanism (60) configured to drive rotation of an output drive (88) about a second axis (86) that is non-parallel to the first axis (42), the impact mechanism (60) comprising an anvil (110) configured to rotate about the second axis (86) and a hammer (100) configured to rotate about the second axis to periodically deliver an impact load to the anvil, a gear assembly (58) configured to be driven by the output shaft (40) of the motor (16), the gear assembly (58) including a drive gear (84) configured to drive the hammer (100) of the impact mechanism (60), and a conical spring (106) positioned between the hammer (100) and the drive gear (84), the conical spring (106) biasing the hammer away from the drive gear.