Locking Nut Cam Mechanism for Proportional Pump Dosing Precision
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Solution Overview
Problem
Proportional metering pumps face issues with unreliable locking mechanisms, leading to imprecise dosing due to user-dependent tightening and potential disassembly of locking rings, causing involuntary separation between the nozzle and hydraulic machine.
Innovation Solution
A metering mechanism with a ring housed in a locking nut that cooperates with the adjustment nut, allowing for secure locking and unlocking through complementary shapes, preventing screwing and unscrewing, and utilizing a circlip for additional stability, along with dosage display and sealing features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking ring is used to prevent rotation of the adjusting nut, then the dosing position can be maintained, but the locking mechanism becomes unreliable and may come loose due to user-dependent tightening
Solution Approach 1:
The locking mechanism uses a cam-shaped surface that automatically engages with a stop on the adjusting nut when the locking ring is rotated into position. This self-locking feature eliminates the need for user judgment about tightening force, as the geometry itself provides the locking action. The system serves itself by using the rotational movement to automatically engage the lock rather than relying on user-applied friction.
Solution Approach 2:
The cam-shaped surface of the locking ring creates an asymmetric geometric relationship with the stop on the adjusting nut. This asymmetric geometry ensures that once engaged, the locking ring cannot back out or rotate loosely, providing deterministic locking behavior that is independent of user tightening force. The asymmetric shape converts rotational movement into a mechanical lock.
2Device complexity
If the locking mechanism depends on user tightening force, then the structure remains simple, but precise control of the locking position becomes imprecise
Solution Approach 1:
The invention replaces the friction-based mechanical tightening system with a geometry-based locking system. Instead of relying on the friction force generated by user tightening, the system uses the cam-shaped surface geometry to provide a deterministic mechanical lock. This substitution maintains relative structural simplicity while dramatically improving positioning precision.
3Adaptability or versatility
If the locking ring can be easily rotated for adjustment, then the dosing volume can be modified, but unintentional separation between the nozzle and hydraulic machine may occur
Solution Approach 1:
The locking mechanism provides dynamic control where the locking state can be intentionally changed by rotating the locking ring. During normal operation, the cam surface keeps the locking ring engaged. When adjustment is needed, the user rotates the locking ring to disengage the cam from the stop, allowing adjustment of the adjusting nut. After adjustment, rotating the locking ring back re-engages the cam, providing secure locking. This dynamic system allows both adjustability and stability.
Data Source
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AI summary
The invention relates to a metering mechanism (7) comprising a body (70) mounted in a sleeve (77) covering it by the top and in an adjustment nut (71) covering it by the bottom, said adjustment nut being able to engage by screw connection with said sleeve, said screw connection then causing rotation of the adjustment nut with respect to the body of the metering mechanism, said body being extended by a valve seat (75) that can be closed by a valve (76) and that is able to receive a plunger (8) of which the reciprocating motion permits intake at the valve (76), the travel of the plunger depending on the screw position between the adjustment nut and the sleeve, characterized in that the metering mechanism further comprises means (M) to lock the rotation between the adjustment nut (71) and the body of the metering mechanism (70) so as to prevent the adjustment nut being screwed or unscrewed on the sleeve. The invention also relates to a method for locking and unlocking such a mechanism, and to a proportional metering pump incorporating such a mechanism.