Plate-Based Cam Follower Lever for Precise Roller Mounting

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Solution Overview

Problem

Existing cam armor mechanics output levers with follower rollers are costly to manufacture due to machining requirements, which lead to internal stresses and deformations, necessitating additional straightening operations and precise positioning to manage torsional forces and prevent premature failure.

Innovation Solution

A cam armor mechanics follower roller output lever with a body formed in a plate, featuring two opposite faces with a central bore and attachment portions, where follower rollers are offset and connected via an attachment device comprising inner and outer flanges and spacer rings, allowing for simple and cost-effective assembly without surface machining, using rivets for fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If machining operations are used to mount rollers to the lever body, then precise positioning of rollers relative to cams is achieved, but manufacturing cost increases and internal stresses cause deformations

Engineering Contradiction:
Improveroller positioning precisionVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The lever body is divided into a main body and separate attachment portions that are formed radially outward from the central axis. These attachment portions are distinct segments that can be manufactured separately and assembled, eliminating the need for complex machining of the entire lever body while maintaining precise roller positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Attachment portions serve as intermediary elements between the lever body and the rollers. These intermediate structures provide the necessary mounting surfaces and positioning features without requiring direct machining of the main lever body, thus reducing manufacturing complexity while ensuring precise roller placement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If machining operations are performed on the lever body, then roller mounting precision is improved, but internal stresses are released causing deformations

Engineering Contradiction:
Improveroller mounting precisionVSAvoidlever body stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

By segmenting the lever body into a main body and separate attachment portions, the machining operations are confined to the attachment portions rather than the entire lever body. This segmentation prevents stress release in the main body, maintaining its structural stability while still achieving precise roller mounting on the attachment portions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment portions have localized machining features specifically where needed for roller mounting, while the main lever body remains unmachined and retains its original structural integrity. This local quality approach ensures precision where required without compromising overall stability.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If additional straightening operations are performed to compensate for deformations, then lever straightness is restored, but manufacturing time and cost increase

Engineering Contradiction:
Improvelever straightnessVSAvoidmanufacturing cycle time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The segmentation of the lever body into main body and attachment portions prevents deformations from occurring in the first place, eliminating the need for subsequent straightening operations. The attachment portions are designed and manufactured as separate elements that are assembled to the main body without inducing stresses that would require correction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment portions are pre-formed with the correct geometry and positioning features before assembly to the main lever body. This preliminary formation ensures that rollers will be correctly positioned without requiring post-assembly straightening or adjustment operations.

Inventive Principle:
Principle #10Preliminary action

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 reduces manufacturing costs and eliminates the need for expensive machining, providing a durable and precise attachment method that maintains the rollers' alignment and reduces the risk of premature failure by using a simple, plate-based geometry and rivet assembly.

Implementation Method 1

The roller bearing converts sliding friction between the cam track and lever into rolling friction, reducing wear and improving efficiency

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 2

The rivets create a permanent mechanical joint by deformation, joining the attachment portions to the lever body

Methodology Applied
Scientific EffectMechanical fastening: Mechanical Fastener

Data Source

PatentEP3922766B1Outlet lever with cam dobby follower rollers and method for manufacturing same, shedding machine provided with such a lever and weaving loom equipped with such a machine
Publication Date: 2023.11.01 STAUBLI FAVERGES SA
  • EP3922766B1 patent drawingFigure 1
  • EP3922766B1 patent drawingFigure 2
  • EP3922766B1 patent drawingFigure 3

AI summary

A cam-operated roller-follower release lever (11) comprises two follower rollers (24A, 24B) connected to a body (110). The body defines a median plane (P11) and includes a central portion (116) with two opposing surfaces (117A, 117B) and two attachment portions (122A, 122B), each connected, by means of a respective attachment device (28), to a respective follower roller. Each attachment device comprises an inner attachment (28A) and an outer attachment (28B), each of which includes one or more flanges (30, 32, 34; 30, 32, 34, 70). The flanges are each formed in a plate and are supported planar-to-planar with each other. Each follower roller is mounted in a clevis between the inner attachment and the outer attachment so that contact surfaces (S242) of the two follower rollers are located on either side of the median plane.A first follower roller is fixed, by means of a first fastening device, to one of two attachment portions comprising two opposing surfaces (123A, 123B), which are connected by a rim (124), separated from each other by a distance equal to the thickness of the central portion, and each coplanar with a respective surface of the central portion. The contact surface of the first follower roller is located opposite the rim of the first attachment portion.