Spring Arm Toothed Profile for Rotary Encoder Pressure Adjustment

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Solution Overview

Problem

Conventional spring arm joints for measuring devices, such as rotary encoders with measuring wheels, face difficulties in easily and precisely setting desired contact pressure, often requiring adjustment after installation and risking displacement due to excessive pressure.

Innovation Solution

The integration of toothed profiles on the base plate and bearing housing allows for precise adjustment of contact pressure by twisting the spring arm in defined intervals, with each interval step corresponding to a known increase in pressure, and features like rounded crests and valleys prevent jamming and ensure a positive connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional spring arm joints are used, then the measuring device can be mounted on a moving surface, but the contact pressure cannot be easily or precisely adjusted

Engineering Contradiction:
Improveadjustability of contact pressureVSAvoidprecision of contact pressure setting
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The joint unit is divided into discrete angular positions using a toothed profile with multiple crests and valleys. The bearing housing can be rotated to align with different teeth on the base plate, creating segmented adjustment positions. Each position corresponds to a predetermined contact pressure value, enabling precise and easy adjustment without continuous variation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact pressure is adjusted by changing the angular position of the bearing housing relative to the base plate. The toothed profile provides discrete angular positions, each corresponding to a specific contact pressure parameter. This allows the contact pressure to be varied in predetermined steps while maintaining precise control.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the spring arm is adjusted to increase contact pressure for better measurement, then measurement accuracy improves, but the joint may fail due to excessive pressure

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidjoint stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The toothed profile provides a positive locking mechanism that prevents the bearing housing from rotating beyond the intended adjustment position. The crests and valleys engage to mechanically limit the maximum contact pressure, preventing excessive force that could damage the joint or cause displacement, while still allowing sufficient pressure for accurate measurement.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The toothed profile provides tactile and visual feedback during adjustment. As the bearing housing is rotated, the operator can feel the discrete positions indicated by the teeth engagement and see the alignment of crests and valleys. This feedback allows the operator to know when the desired contact pressure is achieved and prevents over-adjustment that could lead to excessive pressure.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the joint allows rotation for adjustment, then contact pressure can be modified, but the joint may become displaced under load

Engineering Contradiction:
ImproveadjustabilityVSAvoidjoint position stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The continuous rotational range is segmented into discrete positions by the toothed profile. The bearing housing can only be positioned at specific angular locations where the crests and valleys align, preventing unintended continuous rotation or displacement under load while maintaining the ability to adjust to different positions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The toothed profile provides self-locking functionality. Once the bearing housing is rotated to a desired position and the crests and valleys engage, the joint automatically locks in place without requiring additional locking mechanisms. The mechanical engagement of the teeth prevents the joint from rotating or displacing under the applied contact pressure load.

Inventive Principle:
Principle #25Self-service

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

Enables easy, precise, and repeatable adjustment of contact pressure, preventing displacement and ensuring accurate measurement without the need for post-adjustment pressure measurement, while maintaining a secure frictional connection.

Implementation Method 1

the base plate and the bearing housing have a toothed profile in at least one section on the respective end faces of the base plate or the bearing housing which mesh when the measuring device is in operation

Methodology Applied
Scientific EffectMechanical Fastener: Mechanical Fastener

Implementation Method 2

A spring element 12 is arranged on the spring arm axis 46, in particular designed in the form of a torsion spring

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

the crests and/or valleys of the toothed profiles are at least partially rounded in order to prevent the toothed profiles from jamming when adjusting the contact pressure

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3118588B1Spring arm for a measuring instrument with a toothed profile
Publication Date: 2018.11.21 WACHENDORFF AUTOMATION
  • EP3118588B1 patent drawingFigure 1
  • EP3118588B1 patent drawingFigure 2
  • EP3118588B1 patent drawingFigure 3

AI summary

A spring arm for a measuring instrument, in particular a rotary encoder with a measuring wheel, comprising a rocker arm, one end of which is shaped to receive a measuring instrument and the other end of which is assigned a joint unit, wherein the joint unit comprises a stationary base plate and a bearing housing rotatably mounted on the rocker arm about an axis of rotation perpendicular to the base plate in the mounting or adjustment mode. The design is intended to enable particularly easy and simple adjustment of the desired contact pressure of the measuring instrument on the object to be measured and simultaneously prevent rotation of the joint due to excessive contact pressure. For this purpose, the base plate and the bearing housing have a toothed profile on at least one section of their respective facing end faces.