Cremone Bolt Locking with Rack-and-Pinion Actuation
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Solution Overview
Problem
Current cremone-bolt door-locking systems using 'European' profile cylinders experience jerky movement, require multiple key turns for full engagement, and are fragile due to wide outer envelopes and complex assemblies, leading to unsatisfactory operation and potential damage.
Innovation Solution
A cremone-bolt door-locking device with slidably mounted rack supports and a pinion system that allows actuation over the entire stroke of a rotor or knob, featuring hinged rack segments with teeth engaging a pinion, ensuring irreversible movement and reduced force requirements, and a compact cylindrical housing for reduced diameter compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a Euro cylinder lock system is used, then the locking mechanism can be actuated, but the cremone-bolt movement becomes jerky and sudden with successive jolts
Solution Approach 1:
The patent replaces the traditional Euro cylinder bit-and-piston mechanical system with a rack-and-pinion mechanism. This substitution transforms the jerky piston-driven motion into smooth continuous rotation of the pinion gear, which directly drives the cremone-bolt rods through rack segments, eliminating the successive jolts while maintaining actuation capability
Solution Approach 2:
The invention introduces dynamic elements including a freely rotatable pinion supported by bearings, and hinged rack segments that can pivot at the end of stroke. This dynamic design allows the mechanism to absorb stresses and maintain smooth operation throughout the actuation cycle, preventing the jerky movement characteristic of rigid piston systems
2Productivity
If a Euro cylinder lock system is used, then the locking mechanism can be actuated, but at least two turns of the key are required to engage the lock-bolts to sufficient depth
Solution Approach 1:
The rack-and-pinion mechanism enables continuous useful action throughout the entire key rotation. As the pinion rotates continuously, it drives both rack segments simultaneously, ensuring that the cremone-bolt rods are engaged continuously from start to finish of the key turn, eliminating the need for multiple turns and reducing engagement time
Solution Approach 2:
The patent divides the driving mechanism into two rack segments that can move in opposite directions, each engaged with the pinion. This segmentation allows simultaneous actuation of multiple cremone-bolt rods, achieving full engagement in a single continuous motion rather than requiring sequential engagement through multiple key turns
3Volume of moving object
If a Euro cylinder lock system is used, then the locking mechanism can be actuated, but the outer envelope swept by the turning bit is very wide requiring a tube with inside diameter greater than 32 mm
Solution Approach 1:
The patent inverts the traditional approach by placing the rotating pinion inside a compact cylindrical housing rather than having a wide bit envelope. The pinion rotates within the housing, driving the rack segments linearly, which reverses the spatial requirements and enables a much smaller housing diameter while maintaining full actuation functionality
Solution Approach 2:
The mechanism is nested within a compact cylindrical housing that contains the pinion, rack segments, and supporting structures in a space-efficient arrangement. The cremone-bolt rods extend from this compact housing, creating a nested configuration that minimizes the overall diameter while accommodating all necessary components
4Reliability
If a Euro cylinder lock system is used, then the locking mechanism can be actuated, but the assembly of parts is fragile and can be damaged rapidly by abnormal stresses
Solution Approach 1:
The mechanism employs dynamic elements including a freely rotatable pinion supported by bearings and hinged rack segments that can pivot. These dynamic features allow the system to absorb and redistribute abnormal stresses through controlled movement, preventing the rigid stress concentration that causes fragile components to fail in traditional piston-based systems
Solution Approach 2:
The hinged rack segments are designed to pivot at the end of their stroke, providing a cushioning effect that prevents rigid impact and stress concentration. This beforehand cushioning protects the fragile rack teeth and pinion teeth from damage by abnormal stresses, enhancing the overall durability of the mechanism
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 enables smooth, single-turn key operation with constant force, enhances durability by distributing stress, and reduces the housing diameter, making the system more compact and robust, suitable for dual locking and easy installation in tubular uprights.
Implementation Method 1
each rack support carries a rack segment provided with a set of teeth in engagement with a pinion installed between the two rack segments
Implementation Method 2
the set of teeth of said hinged rack segment is extended over a curved portion of a free end of said segment so as to enable said hinged rack segment to pivot at the end of the stroke and to be braced
Implementation Method 3
each rack support carries a rack segment provided with a set of teeth in engagement with a pinion installed between the two rack segments
Implementation Method 4
actuation is distributed over the entire stroke of the rotor of the lock and not merely over one eighth of its stroke
Data Source
AI summary
Cremone-bolt door-locking controlled by rack-and-pinion means. The cremone-bolt rod is connected to a first rack support that is slidably mounted inside a housing that houses a second slidably mounted rack support, each rack support carrying a rack segment in engagement with a pinion, at least one rack segment being hinged to its own rack support and being provided with a set of teeth that is extended over a curved portion of its end.