Composite Cam Drive Transmission for Low-Torque Sheet Feeding
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Solution Overview
Problem
Existing sheet transporting apparatuses face issues with torque fluctuations and increased wear due to shifting contact points between cams and lift plates, leading to inefficiencies and potential mechanical failures in drive transmission systems.
Innovation Solution
A drive transmission device with a composite cam system featuring a first and second cam, where the cam follower switches contact from the outer edge to the inner edge, reducing torque and wear by maintaining equal pressing forces and minimizing sliding contact, thereby stabilizing the rotation shaft and gear train.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single eccentric cam is used to drive the lift plate, then the lifting function is achieved, but the contact point between cam and follower shifts during rotation causing torque fluctuations and increased wear
Solution Approach 1:
The single eccentric cam is divided into two separate cams: a first cam with an outer edge portion and a second cam with an inner edge portion. The cam follower switches between contacting the outer edge of the first cam and the inner edge of the second cam, segmenting the contact zones to reduce torque fluctuations and wear during rotation.
2Speed
If the cam follower contacts the outer edge of the first cam during rotation, then lifting motion is generated, but the distance from rotation center increases causing higher torque requirements
Solution Approach 1:
The cam profile is segmented into two distinct zones: the first cam for outward motion generation and the second cam for return motion. By switching between these segments, the system optimizes the balance between lifting speed and torque requirements at different phases of the cycle.
Solution Approach 2:
Instead of using a single cam profile that requires high torque throughout rotation, the invention uses two cams where the second cam with inner edge contact provides a mechanical advantage by reducing the moment arm, thereby lowering torque requirements during the return phase.
3Power
If the cam follower contacts the inner edge of the second cam, then torque is reduced, but the contact point shifts along the cam surface causing wear
Solution Approach 1:
The contact surface is segmented into two distinct cam profiles with different edge geometries. The first cam's outer edge and the second cam's inner edge are designed to alternate contact with the follower, distributing wear across two separate contact zones and improving overall durability.
4Device complexity
If a single cam profile is used, then device complexity is low, but torque fluctuations increase mechanical stress on the drive train
Solution Approach 1:
The cam mechanism is segmented into two separate cam profiles mounted on the same rotation shaft. While this increases component count slightly, it significantly reduces torque fluctuations and mechanical stress on the drive train by distributing the load more evenly throughout the rotation cycle.
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 torque fluctuations and wear, enhancing the stability and efficiency of the drive transmission system by maintaining consistent contact forces and positions, thus preventing mechanical failures and improving the overall performance of the sheet transporting apparatus.
Implementation Method 1
a cam portion (82) configured to rotate about a rotation shaft (78); a cam follower (104) configured to be in contact with the cam portion (82) and move, by rotation of the cam portion, in a first direction (+B direction) to be close to the rotation shaft (78) and in a second direction (-B direction) to be away from the rotation shaft (78)
Implementation Method 2
a pressing portion (61, 160) configured to press the cam follower (104) against the cam portion (82)
Implementation Method 3
a brake member (160) configured to impede the rotation of the cam portion (82)
Data Source
AI summary
A drive transmission unit includes a cam member, a motor, a cam follower, and an extension spring. The cam member rotates about a rotation shaft. The cam member includes a first cam defining a maximum distance between the cam follower and the rotation shaft and a second cam having an outer peripheral surface positioned closer to the rotation shaft than the outer peripheral surface of the first cam. The motor rotates the rotation shaft. The cam follower is to be in contact with the cam member and moves in the +B direction and the −B direction by the rotation of the cam member. The extension spring presses the cam follower against the cam member. When the cam follower moves in the −B direction by the rotation of the cam member, this operation includes contact between the outer peripheral surface of the second cam and the cam follower.