Retractor Sensor Assembly and Stop for Over-Retraction Control
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Solution Overview
Problem
Existing wheelchair retractor systems face issues such as reduced jamming due to over-retraction, precise wheelchair positioning, and potential damage to vehicle surfaces during operation.
Innovation Solution
Incorporation of a sensor assembly with an indicator element and stop member to detect the length of restraint withdrawal, preventing further retraction and using a breakaway hanger to protect vehicle surfaces from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the retractor allows continuous retraction of the restraint, then the restraint can be fully retracted into the retractor housing, but the retractor may jam due to over-retraction
Solution Approach 1:
A stop member is introduced as an intermediary element between the restraint and the retractor housing. This stop member engages with the housing to prevent excessive retraction, thereby avoiding jamming while allowing normal retraction operation. The stop member acts as a mediator that controls the boundary of the retraction movement.
2Productivity
If the sensor assembly detects the indicator element early in the retraction process, then the motor can be turned off promptly, but the restraint may not be fully retracted before stopping
Solution Approach 1:
The indicator element is positioned in advance on the restraint at a specific location that corresponds to the desired stopping point. The sensor assembly is pre-configured to detect this indicator element, enabling the motor controller to turn off the motor at the precise moment when the restraint reaches the correct position, ensuring both speed and precision.
3Quantity of substance
If the restraint is allowed to over-retract into the housing, then the retractor can accommodate more restraint length, but vehicle paneling or surfaces may be damaged
Solution Approach 1:
The stop member is positioned to engage with the retractor housing before the restraint can over-retract and cause damage to the vehicle surface. This preliminary engagement prevents the harmful effect of surface damage by blocking the excessive retraction movement in advance, while still allowing sufficient restraint length to be accommodated during normal operation.
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
Prevents retractor jamming and ensures precise wheelchair positioning while safeguarding vehicle surfaces from damage.
Implementation Method 1
a sensor assembly that generates a signal when the indicator element is within a detection range of the sensor
Data Source
AI summary
A retractor with a sensor assembly, comprising an indicator element and a sensor assembly that generates a signal when the indicator element is within a detection range of the sensor, for detecting the length of withdrawn restraint. The indicator element can be located anywhere along the length of the restraint. In one implementation, the retractor is a motorized retractor and the location of the indicator element is selected whereby the sensor generates the signal when the restraint is nearly or fully withdrawn. In an alternative implementation, the retractor is a motorized retractor configured to winch a wheelchair into a wheelchair securement area of a vehicle and the location of the indicator element is selected whereby the sensor detects the indicator element when a wheelchair is in a desired securement position.