Material Web Shaft With Tension-Rope Torque Drive
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Solution Overview
Problem
Existing devices for rolling up and unrolling a material web onto and from a shaft are complex, expensive, and prone to faults due to numerous components, and they struggle to maintain sufficient tension and reliable driving, especially when the material web is unrolled horizontally or obliquely.
Innovation Solution
A device with a simplified design using only three essential components: a shaft, a material web, and two tensioning ropes, where the tensioning ropes serve to both tension and guide the material web, and drive the shaft by creating a torque difference through varying radial distances from the axis of rotation, eliminating the need for separate driving mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate driving mechanism (motor or Bowden cable) is used to rotate the shaft, then the shaft can be reliably driven horizontally or obliquely, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the driving function with the tensioning function by integrating the tensioning rope system directly onto the shaft. The tensioning ropes are wound around the shaft in such a way that their tension creates a torque that automatically drives the shaft, eliminating the need for separate motors or cable mechanisms.
Solution Approach 2:
The tensioning ropes serve dual purposes: they maintain web tension and simultaneously provide the driving torque for shaft rotation. The system is self-driven through the mechanical interaction between the tensioning ropes and the shaft, without requiring external power sources or additional driving components.
2Reliability
If conical rim portions are used to maintain constant radial distance of tensioning ropes, then uniform web tension is achieved, but the device complexity increases
Solution Approach 1:
The shaft features conical rim portions at its ends rather than a uniformly cylindrical shape. This local geometric modification creates the necessary variation in radial distance along the shaft length, allowing the tensioning ropes to maintain optimal tension as they wind and unwind during shaft rotation.
3Reliability
If the radial distance of tensioning ropes remains constant during unrolling, then uniform web tension is maintained, but the radial distance of material web from axis decreases with increasing roll-out length
Solution Approach 1:
The shaft geometry is designed to dynamically adapt to the changing conditions during web unrolling. As the shaft rotates and the web pays out, the conical rim portions ensure that the tensioning ropes maintain a consistent radial relationship with the shaft axis, compensating for the natural decrease in radial distance that would occur with a cylindrical shaft.
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 device ensures consistent web tension and reliable shaft driving across various orientations, reducing component complexity and manufacturing costs while minimizing faults, as the tensioning ropes both guide and drive the shaft, maintaining constant torque for efficient unrolling and rolling.
Implementation Method 1
a first radial distance assigned to any given roll-out length of the material web, between the material web and an axis of rotation of the shaft, differs from a second radial distance assigned to this roll-out length, between a tensioning rope and the axis of rotation of the shaft
Implementation Method 2
the shaft is driven by the gravity acting thereon and set in rotation, causing the material web to unroll from the shaft
Data Source
AI summary
The present invention discloses a device for rolling up and unrolling a material web (2) on a shaft (1, 15). The device is distinguished by the fact that a first radial spacing (R1) of the material web (2) from a rotational axis of the shaft (1, 15), which first radial spacing (R1) is assigned to any desired unrolled length (L) of the material web (2), differs from a second radial spacing (R2) of a tensioning cable (3, 16) from the rotational axis of the shaft (1, 15), which second radial spacing (R2) is assigned to said unrolled length (L), with the result that the direction and magnitude of a first torque which is exerted on the shaft (1, 15) via the material web (2) differ from those of a second torque which is exerted on the shaft (1, 15) via the tensioning cables (3, 16), in such a way that, on account of the torque difference between the first torque and the second torque, the shaft (1, 15) is driven by a force (F) which is transmitted by means of the tensioning cables (3, 16).