Sinusoidal Winch Drum Teeth for Single-Pass Capstan Grip
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Solution Overview
Problem
Traditional winch and hoist devices experience wear and inefficiency due to line wrapping issues, as the line often overlaps or rubs against itself, leading to reduced friction and increased wear, necessitating multiple passes around the drum for effective capstan-effect operation.
Innovation Solution
A winch drum design featuring a sinusoidal channel created by axially shifted and offset teeth, which guides the line through a tortuous path, increasing surface area and friction at each redirection, allowing a single pass to achieve the capstan effect, with a trough that narrows from top to bottom to grip the line as it enters, enhancing engagement and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the line is wrapped around the drum multiple times to achieve sufficient friction for the capstan effect, then the lifting and pulling capability is improved, but the line wear increases and the operation efficiency decreases
Solution Approach 1:
The patent introduces a sinusoidal channel that forces the line to follow a three-dimensional tortuous path around the drum, transforming the simple circular wrapping into a complex spatial trajectory. This dimensional transformation increases the effective contact length and friction force without requiring multiple separate wraps, thereby reducing line wear while maintaining the capstan effect.
Solution Approach 2:
The sinusoidal channel creates curved and angled contact surfaces along the drum perimeter, forcing the line to change direction continuously. These curvature-induced redirections increase the normal force between the line and drum surface, enhancing friction engagement while distributing wear more evenly across the line length.
2Reliability
If the line is wrapped multiple times around the drum to ensure adequate grip, then the lifting reliability is improved, but the time required for operation increases
Solution Approach 1:
By transforming the wrapping path into a sinusoidal three-dimensional trajectory, the patent achieves sufficient friction engagement in a single pass around the drum. The increased path length and directional changes within this single wrap provide reliable grip without requiring multiple sequential wraps, thereby reducing operation time while maintaining reliability.
3Device complexity
If the line follows a simple circular path around the drum, then the device complexity is minimized, but the friction engagement is insufficient for effective capstan operation
Solution Approach 1:
The sinusoidal channel is formed by two sets of teeth that are axially shifted and offset from each other, creating a segmented structure. This segmentation allows the channel to guide the line through multiple directional changes along the sinusoidal path, increasing friction engagement while maintaining a relatively simple drum structure with only two tooth sets.
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 sinusoidal channel design amplifies the capstan effect by increasing friction along the line's path, reducing wear and the need for multiple passes, while the trough's design ensures consistent grip, improving the winch's ability to lift and lower objects efficiently.
Implementation Method 1
each change of direction along the sinusoidal path causes the line to engage by friction with the first bases and the second bases
Implementation Method 2
The trough is narrower at a bottom of the trough. The trough is wider at a top of the trough. The line engages the winch drum by snaking through a bottom of the trough
Data Source
AI summary
A winch drum is disclosed. In a first aspect, a first set of teeth are positioned around an outer perimeter of a drum. The first set of teeth taper from a first crown to a first base. A second set of teeth are positioned around the outer perimeter of the drum. The second set of teeth taper from a second crown to a second base. The second set of teeth are offset from the first set of teeth such that a gap between the first bases and the second bases forms a sinusoidal channel for a line to follow the first set of teeth and the second set of teeth becomes a guide for the line so that the line can engage the sinusoidal channel. The line follows the sinusoidal channel and each change of direction along the sinusoidal path causes the line to engage by friction with the first bases and the second bases. In a second aspect, the drum includes a trough that follows a sinusoidal path and wherein the trough is narrower at its bottom than at its top.