Chair Tilting Fitting With Adjustable Spring Resistance Locking
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Solution Overview
Problem
Existing tilting fitting devices for chairs face operational drawbacks, including the need for vigorous tilting to adjust spring resistance and limited options for fixing desired tilting positions due to the volume occupied by tilt-resisting springs, which restricts the number of adjustable positions.
Innovation Solution
The device employs a first pair of tilt-resisting springs with fixed spacing for neutral position holding and a second pair of eccentrically supported, spacing-adjustable springs, along with a toothed wheel mechanism and actuating element for adjusting spring spacing, and a tilt lock system using tooth-equipped engaging members for locking at desired positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If axial movement of springs is used to adjust spacing, then spring resistance can be adjusted, but the chair seat must be tilted vigorously backwards or forwards to release the springs for movement
Solution Approach 1:
A rack (actuating element) serves as an intermediary mechanism between the user's simple rotational input and the spring spacing adjustment. The rack engages with pinions on the support members, converting rotational motion into linear motion that adjusts spring spacing without requiring vigorous tilting of the chair seat.
Solution Approach 2:
The direct mechanical coupling between spring spacing and chair tilt angle is replaced by a decoupled mechanism using racks and pinions. This allows independent adjustment of spring spacing through rotational motion of the rack, substituting the complex vigorous tilting action with a simpler rotational adjustment.
2Adaptability or versatility
If tilt-resisting springs occupy major volume for adjustment possibilities, then multiple tilting positions can be achieved, but the device becomes less compact
Solution Approach 1:
The support members are made rotatable rather than fixed, allowing the springs to change position dynamically. This rotational capability enables multiple tilting positions to be achieved within a compact volume by repositioning the springs along their support members' circumferences rather than requiring large linear adjustment spaces.
Solution Approach 2:
Spring positioning is moved from a linear adjustment dimension to a rotational dimension. The pinion-rack mechanism converts linear rack movement into rotational movement of the support members, allowing compact adjustment of spring positions in multiple dimensions without increasing overall device volume.
3Force
If springs are positioned to provide sufficient resistance in neutral position, then tilting resistance is adequate, but the control unit must be tilted vigorously to release springs for movement
Solution Approach 1:
The spring resistance function is segmented into two independent systems: the first pair of springs (2, 3) provides fixed resistance for neutral position stability, while the second pair of springs (4, 5) on rotatable support members allows adjustable resistance and easy movement initiation through the rack mechanism.
Solution Approach 2:
The support members for springs 4 and 5 are made rotatable, allowing dynamic adjustment of spring positioning. This enables the springs to be optimally positioned for both providing sufficient resistance in neutral position and allowing easy release and movement through the rack-driven rotational adjustment.
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 solution allows for adjustable spring resistance and multiple tilting positions with a single control knob, enhancing user convenience and flexibility in chair seat tilting, while maintaining compactness and preventing jamming issues.
Implementation Method 1
tilting resistance is adjustable by adjusting spacing between the tilt-resisting springs
Implementation Method 2
each of the support members is provided with a segment of a toothed wheel, wherein an actuating element is arranged for simultaneous engagement with the two support members
Implementation Method 3
each spring is eccentrically supported on or in the lower part on a respective rotatable support member
Data Source
Figure 1~2
Figure 3~4
Figure 5~12
AI summary
A tilting fitting device for a chair to enable a chair seat when fitted to the device to be tiltable forwards and backwards against spring force of tilt-resisting springs, the tilting fitting having an upper part that is fastenable to the chair seat and a lower part that is fastenable to a chair base and tiltably connected to the upper part, wherein the tilting resistance is adjustable by adjusting spacing between the tilt-resisting springs and distance of each spring from a respective side of a tilting axis for the upper part. The lower part is provided with a first and a second pair of tilt-resisting springs, wherein the first pair of tilt-resisting springs are located on a respective side of the tilting axis, and have fixed spacing. In the second pair of tilt-resisting springs, which constitute said spacing-adjustable tilt-resisting springs, each spring is eccentrically supported on or in the lower part on a respective rotatable support member, each of the support members being provided with a segment of a toothed wheel.