Roseless Trim Lock Hardware Compact Bolt Circle Design
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Solution Overview
Problem
Conventional door preparations for architectural hardware require large holes and extensive through bolting, which detract from the appearance of the door system and are not preferred by architects due to the need for large roses to cover mounting components.
Innovation Solution
A roseless trim design that uses a bolt circle of less than one inch, featuring through bolts that pass through curved slots in spindle hubs, allowing for secure and compact installation without interfering with the operation of the lock, requiring only a single hole through the door for both mortise and tubular locks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional through bolting holes are used to secure architectural hardware, then the structural strength and security of the lock installation is improved, but the size of the rose or escutcheon must be large to cover the widely spaced through bolts, which detracts from the appearance of the door system
Solution Approach 1:
The through bolts are segmented into multiple closely spaced bolts arranged on a small diameter bolt circle (less than one inch), rather than using fewer widely spaced bolts. This segmentation allows the bolts to be clustered together, enabling a smaller rose to cover all mounting components while maintaining the required structural strength through distributed fastening points.
Solution Approach 2:
The through bolts are arranged in a two-dimensional pattern on a bolt circle with diameter less than one inch, rather than being distributed in a larger area. This dimensional reorganization of the bolt pattern allows all bolts to be contained within a small circular area, reducing the required rose size while maintaining adequate structural distribution.
2Area of stationary object
If closely spaced through bolts on a bolt circle of less than one inch are used, then the rose size is reduced improving appearance, but the through bolts may interfere with the operation of the spindle hubs in conventional mortise locks
Solution Approach 1:
The spindle hub is designed with dynamic clearance features including curved slots and enlarged openings that allow the hub to move and flex during operation. This dynamic design accommodates the closely spaced through bolts while maintaining full operational range of motion for the spindle hub, resolving the interference issue between compact bolt placement and hub movement.
Solution Approach 2:
The spindle hub incorporates curved slots and rounded openings instead of straight or angular features. The curved geometry provides smoother movement paths and greater clearance for the closely spaced through bolts, allowing the spindle hub to rotate freely without interference from the compact bolt pattern.
3Device complexity
If a single hole through the door is used for both mortise lock and tubular lock, then the number of holes and mounting complexity is reduced, but the through bolts must be closely spaced to fit within the limited space
Solution Approach 1:
The single hole design serves multiple functions: it accommodates both the mortise lock and tubular lock assemblies, provides passage for multiple closely spaced through bolts, and allows for a unified mounting approach. This multi-functional use of a single opening reduces overall mounting complexity despite the increased precision requirements for bolt spacing.
Data Source
AI summary
A roseless trim for a mortise or tubular lock includes through bolts on a bolt circle of less than one inch (25.4 mm). Spindle hubs with a curved slot allow at least one of the through bolts to pass through the spindle hubs. A tubular lock embodiment uses arms with a cutout. The arms function as through bolts when screws attach the arms to mounting plates on opposite sides of the door. Each handle is attached to a corresponding handle base with a bushing. The handle base and small diameter bolt circle cooperate to provide the appearance that the handle extends directly into the door without a rose, escutcheon or any other attachment structure at the base of the handle.