Window Fitting Hand Lever Mounting with Axial Force Absorption
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Solution Overview
Problem
Existing hand lever attachment methods for windows and doors require significant effort, transfer operating and spring forces to the drive device, and are prone to wear, leading to loose fittings and inadequate radial support, especially in tight spaces like all-glass sashes.
Innovation Solution
A polygonal shaft is paired with a wave washer and sleeve, with the shaft and reduced-diameter sleeve penetrating a bore, allowing operating forces to be absorbed by a nut independent of the drive device, which also provides axial and radial support, and features a detent mechanism for position identification using latching springs and a grub screw for secure coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polygonal shaft penetrates the gear and uses a locking element to attach the hand lever, then the hand lever can be securely mounted, but the gear is constantly subjected to axial force causing wear and fatigue over time
Solution Approach 1:
The invention extracts the axial force transmission path from the gear by introducing a separate bearing structure. The bearing supports the polygonal shaft and absorbs axial forces independently, preventing these forces from being transmitted to the gear. This separation of functions protects the gear from fatigue while maintaining secure hand lever mounting.
Solution Approach 2:
The bearing acts as an intermediary element between the polygonal shaft and the housing. It mediates the axial forces by providing a dedicated support path, preventing direct force transmission to the gear. This intermediary structure enables reliable mounting while protecting the drive mechanism from wear.
2Reliability
If three holes are drilled into the visible surface of the sash frame to accommodate the polygonal shaft and fastening screws, then the hand lever can be securely attached, but the installation effort and visible damage to the sash increase
Solution Approach 1:
The invention extracts the fastening function from the visible sash surface by moving it to the rear side. The polygonal shaft and bearing are mounted on the rear surface, eliminating the need to drill holes through the visible face. This maintains attachment security while significantly reducing installation effort and preserving the sash appearance.
Solution Approach 2:
Instead of mounting the hand lever attachment from the front surface (requiring holes in the visible area), the invention inverts the approach by mounting from the rear surface. This reversal allows secure attachment without damaging the visible sash face, reducing both installation effort and aesthetic impact.
3Ease of manufacture
If the polygonal shaft engages the gearwheel with a locking means, then the hand lever can be attached without screws, but free space is required for the polygonal shaft to penetrate the gear
Solution Approach 1:
The invention segments the mounting function into two independent parts: the polygonal shaft for rotational transmission and the bearing for axial support. This segmentation allows the shaft to engage the gearwheel for screwless mounting while the bearing provides the necessary support, enabling compact integration without requiring excessive free space for shaft penetration.
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
This configuration minimizes installation effort, eliminates visible installation space, reduces component demands, and extends the lifespan of the drive device by absorbing axial and radial forces, enabling secure attachment even in narrow spaces without transferring forces to the drive device, thus maintaining operational stability.
Implementation Method 1
A wave washer and a sleeve are assigned to the polygonal shaft, wherein the polygonal shaft and a reduced-diameter section of the sleeve penetrate the bore
Implementation Method 2
the locking is effected by at least one locking spring which engages with a locking projection in a locking recess of the nut
Implementation Method 3
The latter design is simplified in that the locking is effected by at least one locking spring which engages with a locking projection in a locking recess of the nut
Data Source
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AI summary
The invention relates to a window or door fitting with a hand lever which has a polygonal shaft mounted thereon in a rotationally fixed manner, said shaft passing through a bore in the leaf/sash and projecting into a drive device of an espagnolette fitting and being coupled to the latter. In order to achieve the fastening of the hand lever (6) with only minimal effort when processing the leaf/sash (1) and to avoid the transmission of operating forces or spring forces to the drive device and to be able to fasten the arrangement to the leaf/sash (1) as invisibly as possible, there is provision that the polygonal shaft engages at least in certain regions in a follower (12) situated coaxially to the polygonal shaft, said follower being mounted in a housing (15) in a rotatable, but axially non-displaceable manner, wherein the housing (15) is fastened so as to be offset parallel to the drive direction along the axis of rotation of the polygonal shaft (7), and the follower (12) has means which act in the axial direction for coupling to the polygonal shaft (7) in a positively or frictionally locking manner.