Linear Actuator Piezo Squeeze Protection Without Extra Wiring
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Solution Overview
Problem
Existing squeeze protection devices for linear actuators in adjustable furniture are complex, expensive, and difficult to install, often requiring additional wiring and increasing the structural height, while they may not provide adequate safety against injuries due to varying loads and overloading.
Innovation Solution
A compact and integrated squeeze protection device is placed directly with the electric motor, utilizing a piezo element and a compressible part to detect squeezing, which generates a voltage signal to interrupt the motor current, eliminating the need for external wiring and leveraging existing actuator components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a squeeze protection device is added to detect squeezing, then safety is improved, but device complexity increases
Solution Approach 1:
The squeeze protection device is merged with the actuator housing, combining safety detection functionality with the existing actuator structure. The piezo element is integrated into the housing rather than being a separate component, reducing overall device complexity while maintaining safety functionality.
Solution Approach 2:
The actuator housing serves multiple functions: it houses the motor, transmits mechanical forces, and now also houses the squeeze protection device. The compressible part serves dual purposes of mechanical force transmission and activating the squeeze protection mechanism through deformation.
2Reliability
If a squeeze protection device with housing and separate wiring is used, then safety detection is improved, but ease of operation deteriorates
Solution Approach 1:
The squeeze protection device is merged with the actuator housing, eliminating the need for separate wiring and external mounting. All components are integrated within the existing actuator structure, making installation straightforward without additional wiring harnesses or external mounting brackets.
3Reliability
If a squeeze protection device is added to the actuator, then safety is improved, but the constructional height increases
Solution Approach 1:
The squeeze protection device is nested within the existing actuator housing, utilizing the available internal space rather than adding external components. The piezo element and compressible part are positioned within the housing volume, avoiding any increase in the external dimensions of the actuator.
4Device complexity
If motor current measurement is used for squeeze protection, then simplicity is improved, but measurement precision deteriorates
Solution Approach 1:
The electrical measurement method (motor current measurement) is replaced with a direct mechanical sensing method using a piezo element that detects physical deformation of the compressible part. This substitution provides more precise detection of actual squeezing forces regardless of load variations, as the piezo element responds directly to mechanical compression rather than electrical current.
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 safe and simple squeeze protection that is independent of load variations, reduces assembly complexity, and integrates seamlessly with existing actuators, enhancing safety without increasing space or cost.
Implementation Method 1
A linear actuator (8) comprises an electric motor (10), a transmission (11) and a drive tube (12). Arranged in connection with an end of the motor (10) is a squeeze protection device (22), comprising a piezo element (23) and a compressible part (21). The compressible part (21) is positioned so as to be compressed during a squeezing, which activates the piezo element (23), which generates a voltage signal.
Data Source
Figure 1
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Figure 3
AI summary
A linear actuator (8) in which a squeeze protection device is arranged, where the device is located in connection with the rear fixture (17) on the motor (10). The squeeze protection device is based on a piezo element (23), which as a module (22) is built into the actuator (8), so that it is passed through by the forces, exerted by the actuator (8). The piezo element (23) is equipped with cables (30), which are connected to a printed circuit board (31) in the actuator (8), where the connections for the actuator (8) are collected, so that the signal from the squeeze protection in an easy manner may be communicated to a control device (6), which can stop the motor (10) or briefly reverse the direction of the movement and thus release a trapped object.