Electric Lock Actuator with Counter-Spindle for Manipulation Resistance
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Solution Overview
Problem
Conventional electric actuators for locks with rotary-to-linear motion conversion mechanisms are prone to manipulation attempts involving torque or angular momentum pulses, leading to potential spindle drive manipulation due to relative rotary movement between the spindle and housing.
Innovation Solution
The electric actuator design features a drive sub-unit and a driven sub-unit with rotation axes that are parallel but offset, with matched moments of inertia to compensate for rotation caused by torque pulses, and includes a coil spring with variable pitch and a bias mechanism to enhance safety against mechanical manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a spindle drive or rotary-to-linear motion conversion mechanism is used in an electric actuator, then the construction becomes compact, but the actuator becomes vulnerable to manipulation attempts involving torque pulses that cause relative rotary movement between the spindle and housing
Solution Approach 1:
The patent introduces a counter-spindle that rotates in the opposite direction to the main spindle when torque pulses are applied. This counter-rotation compensates for and cancels out the unwanted relative movement between the spindle and housing, thereby maintaining safety against manipulation while preserving the compact spindle drive design.
Solution Approach 2:
The patent employs asymmetric mass distribution and geometric shaping of the spindle and counter-spindle components. By carefully selecting the mass and geometry of these rotating elements, the system creates controlled rotational inertia that enables the counter-spindle to effectively counteract manipulation torques while maintaining compact dimensions.
2Volume of moving object
If conventional electric actuators are designed with compact construction using spindle drives, then space is saved, but repeated torque pulses can manipulate the spindle drive due to inertia-induced relative rotary movement
Solution Approach 1:
The counter-spindle acts as a dynamic counterweight that generates opposing rotational momentum to neutralize the effects of repeated torque pulses. This allows the actuator to maintain its compact volume while becoming resistant to manipulation attempts that rely on exploiting inertia-induced relative movement.
Solution Approach 2:
The patent converts the harmful effect of torque pulse-induced rotation into a beneficial feature by using the same inertial properties to drive the counter-spindle in opposition. The manipulation torques that would normally cause vulnerability are instead harnessed to activate the counter-balancing mechanism, transforming the threat into a protective function.
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 design effectively prevents undesired rotation of the driven shaft during manipulation attempts, ensuring enhanced safety and reliability by canceling out torques and maintaining the lock in a secure position.
Implementation Method 1
The drive sub-unit and the driven sub-unit may have a geometrical shape and mass which are respectively selected such that the driven sub-unit partially or fully compensates a rotation of the drive sub-unit that is caused by a pulse of angular momentum or torque
Implementation Method 2
A first moment of inertia of the drive sub-unit and a second moment of inertia of the driven sub-unit may be matched to each other
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An actuator (20) for an electric lock (1) comprises a stator (14) of an electric motor. The actuator (20) comprises a drive sub-unit which is rotatably mounted. The drive sub-unit comprises a rotor of the electric motor, a drive shaft (22) fixed to the rotor in a torque-proof manner or integral with the rotor, and a drive wheel (23) fixed to the drive shaft (22) in a torque-proof manner. The actuator (20) comprises a driven sub-unit which is rotatably mounted. The driven sub-unit comprises a driven shaft (32) extending parallel to the drive shaft (22), and a driven wheel (33) fixed to the driven shaft (32) in a torque-proof manner, the driven wheel (33) being engaged with the drive wheel (23). The drive sub-unit has a first moment of inertia, I1, and the driven sub-unit has a second moment of inertia, I2, wherein |I1 - I2| / max (I1, I2) is less than 20%.