Variable Speed Dispenser Spindle to Reduce Motor Loading and Overspin
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Solution Overview
Problem
Existing paper dispensers with motor-driven spindles face challenges such as heavy motor loading at the start of dispensing, which reduces motor life, and overspin issues at the end, causing creasing and continued dispensing problems due to constant angular velocity.
Innovation Solution
A dispenser with a variable spindle speed that starts slowly, increases to a maximum in the middle, and decreases back to slow at the end, using a transmission with non-circular gears or conical gear drums to maintain a constant motor rotational speed, allowing for continuous speed change during dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the motor driven spindle operates at constant angular velocity, then the dispensing operation is simple, but the motor is heavily loaded at the start of dispensing which decreases motor life
Solution Approach 1:
The patent applies dynamics by transitioning from constant speed operation to variable speed operation. The spindle speed is dynamically adjusted during dispensing: starting slowly to reduce initial motor loading, increasing to maximum speed in the middle portion, and decreasing toward the end. This dynamic speed variation resolves the contradiction by protecting motor life while maintaining dispensing functionality.
Solution Approach 2:
The patent changes the speed parameter of the spindle throughout the dispensing operation. Instead of maintaining constant angular velocity, the system varies the rotational speed parameter according to the dispensing phase, thereby reducing motor loading at critical moments while preserving the simplicity of the overall dispensing operation.
2Device complexity
If the motor driven spindle operates at constant angular velocity, then the motor control is simple, but the momentum of the spindle causes overspin related problems such as creasing and continued dispensing
Solution Approach 1:
The patent uses dynamic speed adjustment to prevent overspin and associated harmful effects. By decreasing the spindle speed toward the end of dispensing, the system counteracts the momentum that would otherwise cause overspin, creasing, and continued unwanted dispensing, while keeping motor control relatively simple.
Solution Approach 2:
The patent applies preliminary anti-action by reducing spindle speed before the dispensing operation completes. This preemptive speed reduction counteracts the impending momentum-driven overspin and creasing problems, preventing harmful effects before they occur.
3Productivity
If the spindle speed is increased to dispense material faster, then the productivity increases, but the motor loading increases which decreases motor life
Solution Approach 1:
The patent resolves this contradiction by implementing dynamic speed profiling. The spindle operates at high speed during the middle portion of dispensing to maximize productivity, while operating at lower speeds at the beginning and end to protect motor life. This time-varying speed strategy achieves both high productivity and motor reliability.
Data Source
AI summary
A dispenser for a roll of material includes a housing. A roll carrier is disposed within the housing. The roll carrier is configured for rotatably supporting a roll of web material for dispensing. A motor is disposed within the housing, and a spindle is also disposed within the housing. The spindle is configured for engaging the roll of web material between the roll carrier and a free end of the roll of web material. The dispenser also includes features for coupling a rotor of the motor to the spindle such that a rotational speed of the spindle increases from an initial speed to a maximum speed and then decreases to a final speed during dispensing of the roll of web material with the rotor of the motor rotating at a substantially constant rotational speed.