Linear Drive Clutch with Axial Release for Emergency Adjustment
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Solution Overview
Problem
Existing linear drives for adjusting furniture or hospital beds face challenges in quick and simple operation, particularly in emergency situations, due to complex rotary mechanisms and lateral access requirements, leading to complex structures and assemblies.
Innovation Solution
A compact clutch actuation system with two rotatable clamping elements featuring steep threads or ramps, allowing axial operation instead of lateral access, where a sliding element is axially displaceable and a rotating element is fixed axially, enabling quick disengagement for emergency adjustments using a Bowden cable system for remote operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotary mechanism with lateral access is used for clutch operation, then the clutch can be engaged and disengaged, but the structure becomes complex and emergency operation becomes difficult due to access requirements
Solution Approach 1:
The patent inverts the traditional lateral rotary actuation mechanism into an axial linear actuation system. Instead of rotating a knob laterally to disengage the clutch, the invention uses axial linear movement of a sliding element to push the clutch sleeve and disengage the clutch. This inversion simplifies the mechanism and enables easier emergency operation from any position along the linear drive.
Solution Approach 2:
The patent extracts the essential function of clutch disengagement from the complex rotary mechanism and implements it through a simple axial linear actuation system. By removing the rotary components and eccentric mechanisms, the invention retains only the necessary axial movement to push the clutch sleeve, significantly reducing structural complexity while maintaining the clutch engagement/disengagement function.
2Device complexity
If a compact axial actuation system is used instead of lateral rotary mechanism, then the structure becomes simpler and emergency access is improved, but the clutch engagement force must be transmitted through a different mechanism
Solution Approach 1:
The patent introduces a clutch sleeve as an intermediary component that transmits the axial linear force from the sliding element to the clutch teeth. The sliding element axially pushes the clutch sleeve, which in turn pushes the clutch teeth axially to disengage them from the worm gear. This intermediary mechanism effectively transfers the simplified axial actuation force into the necessary clutch disengagement action without requiring complex force transmission paths.
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 provides a simple, quick, and compact operation of the clutch, reducing complexity and enabling emergency adjustments from various positions without the need for radial mechanisms, thus enhancing safety and ease of use in urgent situations.
Implementation Method 1
The clutch is operated via a rotary knob mounted on the gear housing, which adjusts a driver via an eccentric. This driver engages a pin in a groove surrounding the outside of the clutch. By turning the knob, the eccentric moves the clutch from the engaged rest position to the disengaged freewheel position.
Implementation Method 2
The clutch is operated via a rotary knob mounted on the gear housing, which adjusts a driver via an eccentric. This driver engages a pin in a groove surrounding the outside of the clutch. By turning the knob, the eccentric moves the clutch from the engaged rest position to the disengaged freewheel position.
Implementation Method 3
an electric motor which adjusts a lifting tube via a gear so as to be movable relative to a stationary guide tube... The motor drives a shaft with a worm or is provided with a worm at the end, which in turn meshes with a worm gear.
Implementation Method 4
the connection is made via pairs of complementary profile structures on the worm gear and the spindle holder, particularly in the form of splined shaft structures with a complementary profile structure on the inside of the clutch, which thus connects the worm gear and the spindle holder in a rotationally fixed manner.
Data Source
Figure 1~2
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AI summary
The invention relates to a linear drive with a transmission housing (2) and with an electric motor (24) accommodated in said transmission housing, which electric motor drives a shaft (10) with a worm (16). The shaft (10) meshes with a worm wheel (18) which, by means of a clutch (20), is connectable to a spindle holder (22) for conjoint rotation, which spindle holder is connected to a spindle (14) for conjoint rotation. The clutch is preloaded by means of a spring (18) and is adjustable by means of a clutch actuation means. In order to allow simple and fast operation of the clutch, it is proposed that the clutch actuation means comprises a slide element (22) which bears against the clutch (20) and which is arranged so as to be rotationally fixed but axially displaceable in relation to the clutch (20). A rotary element (24) which is axially fixed but rotatable about an axis of rotation engages on the slide element (22) at an outer side averted from the clutch (20). Run-on bevels (22a, 24a) of complementary form are provided between the slide element (22) and the rotary element (24). The rotary element (24) is actuatable via a tensile element.