Door Drive Spring Tensioning via Cover-Mounted Adjusting Screw
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Solution Overview
Problem
The narrow mounting hole pattern in door closers or door drives limits the space for a spring tensioning device, making it difficult to implement a usable adjustment option.
Innovation Solution
A rotatably mounted adjusting nut with a screw supported in a stepped bore of the cover, allowing for external adjustment of the spring preload through a polygonal interface, such as a hexagon, and a sealing ring for a liquid-tight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mounting holes are placed in the edge area of the housing for fastening, then the housing can be securely mounted, but little space remains for arranging a spring tensioning device
Solution Approach 1:
The adjusting screw is relocated from the edge area to the cover area, utilizing a different spatial dimension (the cover surface) for the adjustment function. This separates the mounting function (edge holes) from the adjustment function (cover-mounted screw), resolving the space conflict.
2Adaptability or versatility
If the adjusting screw is mounted on the cover, then the spring tensioning device can be implemented despite narrow hole pattern, but the screw needs secure support and prevention from falling out
Solution Approach 1:
The stepped bore provides different local qualities at different depths: the larger diameter portion secures the screw head with bearing surface, the smaller diameter portion prevents falling out, and the inclined shoulder provides rotational support. This localized structural variation ensures comprehensive screw support.
Solution Approach 2:
The cover integrates multiple functional elements (stepped bore, inclined shoulder, sealing ring groove) into a single composite structure, combining support, retention, and sealing functions in one component.
3Reliability
If a sealing ring is added to the adjusting screw, then liquid-tight seal is achieved, but the device complexity increases
Solution Approach 1:
The sealing ring groove is integrated directly into the adjusting screw, merging the sealing function with the adjustment mechanism. This eliminates the need for separate sealing components and reduces overall device complexity.
Solution Approach 2:
The adjusting screw itself provides the sealing groove, making the screw self-sufficient for both adjustment and sealing functions without requiring additional external sealing components.
Data Source
Figure 1~2
AI summary
The invention relates to a door closer or door drive, comprising a housing, which is closed at one end thereof by a cover, a spring mounted in the housing, and a spring tensioning device for the spring. In order to propose a door closer or door drive for which a usable spring tensioning device can be realized despite the narrow hole pattern, the spring tensioning device comprises an adjusting nut (4), which is rotatably mounted on an adjusting screw (5) so that the adjusting screw (5) is supported in a stepped bore of the cover (6) and is accessible from outside through the cover (6).