Single Follower Cam System for Bookbinding Sewing Machines

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Solution Overview

Problem

Existing cam systems for bookbinding sewing machines are complex and costly, requiring sophisticated manufacturing processes and complex mounting operations, with a high risk of piston seizure and accuracy issues in switching between sewing and separation cycles, which affects the machine's yield and reliability.

Innovation Solution

A cam system with a single follower that can be selectively biased to follow different motion laws using a pneumatic piston, allowing for easy switching between modes without the need for complex lever mechanisms or precise alignment, reducing manufacturing complexity and cost while enhancing reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two cams with corresponding followers and a pneumatic piston are used to switch between sewing and separation cycles, then the motion law of the follower can be changed, but the device complexity increases and manufacturing precision requirements become more stringent

Engineering Contradiction:
Improvemotion law switching capabilityVSAvoidcam system structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges two separate cam systems into a single integrated cam with two different profiles. Instead of using two separate cams with a pneumatic piston to switch between them, the invention combines both motion law definitions into one cam structure, eliminating the need for switching mechanisms and reducing overall system complexity while maintaining the ability to provide different motion laws for sewing and separation cycles

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single cam is designed to perform multiple functions by incorporating two different profiles that can each independently define a motion law. The cam universally serves both the sewing cycle control and the separation cycle control through its dual-profile design, eliminating the need for separate dedicated cams for each function

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

2Adaptability or versatility

If two cams with corresponding followers and a pneumatic piston are used to switch between sewing and separation cycles, then the motion law of the follower can be changed, but manufacturing precision and mounting accuracy requirements increase

Engineering Contradiction:
Improvemotion law switching capabilityVSAvoidcam and piston alignment accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

By combining both motion law definitions into a single cam structure, the invention eliminates the need for precise alignment between two separate cams and a pneumatic piston. The dual-profile cam requires only standard manufacturing tolerances for a single cam component, significantly reducing the cumulative precision requirements and mounting complexity

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a pneumatic piston is used to fasten and unfasten two levers for switching between sewing and separation cycles, then the working mode can be changed, but the risk of piston seizure increases and reliability decreases

Engineering Contradiction:
Improveworking mode switchingVSAvoidpiston seizure risk
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention extracts and removes the pneumatic piston from the cam system entirely. By incorporating both motion laws into a single cam profile, the switching function becomes inherent to the cam's geometry rather than requiring an active switching mechanism. This elimination of the piston completely removes the risk of piston seizure while maintaining the ability to switch between working modes

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The dual-profile cam automatically provides the appropriate motion law based on its geometric design without requiring external control or active switching. The cam structure itself serves the switching function through its inherent geometry, eliminating the need for pneumatic control systems and improving reliability

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

The solution simplifies the cam system structure, reduces manufacturing costs, and improves reliability by allowing easy mode switching without disrupting the sewing process, thereby increasing the machine's yield and reducing downtime.

Implementation Method 1

The second biasing means comprises a pneumatic piston. The pneumatic piston is adapted to bias the follower in the second direction, so as to decouple the follower from the first cam

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Increase

Data Source

PatentEP1953001B1Cam system for bookbinding sewing machines with different biasing of a single follower
Publication Date: 2010.05.19 MECCANOTECNICA SPA
  • EP1953001B1 patent drawingFigure 1
  • EP1953001B1 patent drawingFigure 2a~2b
  • EP1953001B1 patent drawingFigure 2c

AI summary

A cam system (300;400,500) for use in a bookbinding sewing machine (100) is proposed. The cam system includes a follower (315;415;515) for driving at least one member (120-135) of the sewing machine, and control means (305a,305b,335;405a,405b,435;505a,535) for selectively causing the follower to follow a first motion law or a second motion law, the follower driving the at least one member in a first mode or in a second mode when following the first motion law or the second motion law, respectively, wherein the control means includes a first cam (305a;405a;505a) and first biasing means (335;435;535) for biasing the follower in a first direction to couple the follower with the first cam, the follower when coupled with the first cam following the first motion law; the control means further includes second biasing means (335;435;535) for biasing the follower in a second direction to decouple the follower from the first cam, the follower when decoupled from the first cam following the second motion law, and switching means (140) for selectively enabling one of the first biasing means and the second biasing means.