Screw-Nut Drive with Dual Stops to Prevent Release Jamming
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Solution Overview
Problem
Existing screw-nut system drive devices used in strapping devices for airborne combat systems face jamming issues due to excessive torque required to loosen the nut from its stop, leading to potential damage and operational challenges.
Innovation Solution
A screw-nut system with a gear mechanism featuring two toothed wheels with different numbers of teeth, where the stops are configured to limit the angular travel of the threaded rod, preventing jamming by allowing easy rotation in one direction without resistance once locked.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stop is installed on the path of the nut to block its travel in one direction, then the nut's positional control is improved, but the torque required to loosen the nut becomes excessively high causing jamming
Solution Approach 1:
The stop is divided into two separate stops: a first stop that blocks the nut in the tightening direction and a second stop that blocks the nut in the loosening direction. This segmentation allows each stop to independently control one direction of travel without creating excessive resistance in the opposite direction, thereby preventing jamming while maintaining precise positional control.
Solution Approach 2:
The first stop and second stop are positioned asymmetrically on opposite sides of the nut's travel path. The first stop is configured to contact the nut when it approaches the maximum tightening position, while the second stop contacts the nut when it approaches the maximum loosening position. This asymmetric arrangement ensures that each stop only exerts blocking force in its designated direction, allowing easy rotation in the opposite direction without resistance.
2Force
If the threaded rod is rotated to tighten the strapping, then the clamping force is improved, but the risk of over-tightening and damage increases
Solution Approach 1:
The first stop is positioned to contact the nut before excessive tightening can occur. As the threaded rod rotates and the nut moves along it, the first stop provides preliminary blocking action when the nut approaches the maximum safe tightening position, preventing over-tightening and potential damage to the strapping or antenna before it can occur.
3Extent of automation
If a motor is used to drive the threaded rod, then the automation level is improved, but the complexity of the device increases
Solution Approach 1:
The gear mechanism acts as an intermediary between the motor and the threaded rod. The gear transmits and controls the rotational motion from the motor to the threaded rod, providing mechanical advantage and precise control. This intermediary mechanism allows automated operation while managing the complexity through a well-defined mechanical transmission system rather than direct motor coupling.
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 solution prevents jamming and excessive torque requirements, ensuring reliable and reversible operation, allowing for secure clamping and release of objects without mechanical stress, enhancing the safety and efficiency of the strapping device.
Implementation Method 1
a gear, making it possible to transmit a rotational movement to the threaded rod, the gear comprising a first toothed wheel and a second toothed wheel engaged with the first toothed wheel
Implementation Method 2
a screw-nut system comprising a threaded rod and a first nut connected to the threaded rod by means of a helical connection
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention relates to a driving device comprising: a screw-nut system (17) comprising a threaded stem (18) and a first nut (20; 21) linked to the threaded stem (18) by means of a helical link; a gear (30) allowing a rotational movement to be transmitted to the threaded stem (18), a first toothed wheel (33) and a second toothed wheel (34) engaging with the first toothed wheel (33); a set of abutments (31, 32) comprising a first abutment (31) linked to the first wheel (33) rotating about an axis of rotation of the first wheel (33) and a second abutment (32) linked to the second toothed wheel (34) rotating about an axis of rotation of the second wheel (34), the first abutment (31) and the second abutments (32) being configured and arranged so as to engage with one another in order to limit an angular stroke of the threaded stem (18) to a first angular position in a first direction.