Crank Drive With Knee Joint Linkage for Compact Torque
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Solution Overview
Problem
Crank mechanisms with long levers require large space, preventing a compact design and limiting their applications.
Innovation Solution
A crank drive with a displaceably mounted piston connected to a rocker via a connecting rod, allowing for a compact design with a pressure cylinder that can generate strong forces, and a rocker with a bent section to enhance torque transmission through a toggle-joint-like gearing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If long levers are used in the crank mechanism, then the force transmission capability is improved, but the space requirement increases and compact design is prevented
Solution Approach 1:
The patent transitions from a planar mechanism to a three-dimensional spatial mechanism by introducing a knee joint with vertical and horizontal components. The swing arm moves in a vertical plane while the coupler connects to the crank in a horizontal plane, creating a spatial linkage that achieves force transmission without requiring long horizontal levers.
Solution Approach 2:
The knee joint introduces curved motion paths and angular relationships between the swing arm, coupler, and crank. The articulated connections allow for angular adjustments and curved trajectories that efficiently transmit force while maintaining compact dimensions, replacing the straight-line motion of traditional long levers.
2Volume of moving object
If a compact design is implemented, then the space requirement is reduced, but the ability to generate strong forces is compromised
Solution Approach 1:
By utilizing three-dimensional spatial motion through the knee joint configuration, the mechanism achieves force multiplication without increasing the footprint. The vertical component of the swing arm's motion combined with the horizontal crank rotation creates mechanical advantage that generates strong forces within a compact volume.
Solution Approach 2:
The mechanism combines multiple linkage elements (swing arm, coupler, crank) with different functional properties to create a composite system that achieves both compactness and force generation. The articulated connections between these components work together to multiply force while maintaining small overall dimensions.
3Volume of moving object
If the rocker is designed as a short lever arm, then the space requirement is reduced, but the torque generation capability is weakened
Solution Approach 1:
The knee joint configuration transforms the traditional planar rocker into a spatial linkage where the swing arm has both vertical and horizontal components. This three-dimensional arrangement provides mechanical advantage that allows a short rocker to generate the same torque that would require a long lever in a planar mechanism.
Solution Approach 2:
The coupler acts as an intermediary element between the swing arm and the crank, transmitting and amplifying the force generated by the short rocker. The articulated connection in the knee joint allows the coupler to leverage the vertical motion of the swing arm to create rotational torque on the crank, effectively multiplying the force from the compact rocker.
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 compact design enables high torque generation with efficient power amplification and adjustable operation, allowing for a wide range of applications while maintaining a low overall height and reduced axial width.
Implementation Method 1
a first cylinder (12) with a displaceably mounted piston (13) is provided to drive the crank (3), and that the piston (13) and the rocker (1) are connected to one another in an articulated manner via a connecting rod (14), so that the axial movement of the piston (13) moves the rocker (1) in a and reciprocating movement offset
Implementation Method 2
the piston (13) and the rocker (1) are connected to one another in an articulated manner via a connecting rod (14)
Implementation Method 3
the knee-joint-like gearing consisting of the swingarm and the coupling strengthens the torque applied to the crank. With an increasingly stretched alignment of the swingarm and linkage, a sharply increasing torque is transmitted to the crank
Data Source
Figure 1
AI summary
The invention relates to a crank drive, having a frame, which may be formed in particular by a housing, having a rocker (1) positionally fixedly mounted on the frame, having a crank (3) which is positionally fixedly mounted on the frame and which forms the drive output, and having a coupler (5) which connects the rocker (1) and the crank (3), wherein the coupler (5) is articulatedly connected in each case to the crank (3) and to an end, which is situated opposite the positionally fixed mounting (2), of the rocker (1), wherein to drive the crank (3), a first cylinder (12) is provided which has a movably mounted piston (13), wherein the piston (13) and the rocker (1) are articulatedly connected to one another via a push rod (14) such that the axial movement of the piston (13) sets the rocker (1) in an oscillating swinging motion, and wherein the rocker (1) comprises a section (8) which is remote from the positionally fixed mounting of the rocker (1) and which is inclined by a fixed angle towards the coupler (5).