Linear Motor Brake Using Gravity-Actuated Pivot Plate
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Solution Overview
Problem
Linear motors with vertically oriented armatures face challenges in arresting movement when electrical power is lost, particularly in testing equipment setups where the armature may move under gravity, potentially causing issues with sample positioning.
Innovation Solution
A brake mechanism is introduced that utilizes a pivotably mounted plate and an electrically actuable holding member, such as a solenoid, to engage the armature's extension, generating braking force through gravity and releasing it with a controlled pulse of energy from capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the armature is allowed to move freely under gravity when power is lost, then the device is simple and requires no braking mechanism, but the armature cannot be arrested immediately causing safety issues and sample positioning problems
Solution Approach 1:
The brake mechanism utilizes the armature's own weight and gravity to generate the braking force. When power is lost, gravity causes the armature to move downward, which automatically actuates the brake through the mechanical linkage of the pivotable plate and rod, converting the harmful gravitational motion into the useful braking action without requiring external power or complex control systems
Solution Approach 2:
The braking function is extracted from the main electromagnetic ram system and implemented as a separate, independent mechanical brake mechanism. This allows the brake to operate autonomously using gravity and mechanical linkage, independent of the electromagnetic power system, thereby improving reliability while keeping the overall device relatively simple
2Reliability
If a brake mechanism is added to arrest armature movement, then safety and positioning are improved, but the device complexity increases
Solution Approach 1:
A pivotable plate acts as an intermediary mechanical element between the armature rod and the brake inhibiter. This plate translates the vertical motion of the armature into rotational motion that actuates the brake, providing a simple mechanical mediation that connects the moving armature to the braking function without requiring complex linkages or control mechanisms
Solution Approach 2:
Instead of using a motor-driven brake that actively pushes against the armature, the system inverts the approach by using the armature's own gravitational motion to activate a passive mechanical brake. The brake inhibiter normally holds the brake released, and when power fails, the release of this holding force allows gravity to naturally activate the braking action
3Force
If the brake uses gravity to generate braking force, then energy consumption is reduced and reliability is improved, but the braking force may be insufficient for heavy armatures
Solution Approach 1:
The brake mechanism incorporates a resiliently mounted pivot that allows dynamic adjustment of the braking engagement. The spring provides a biasing force that can be overcome by the gravitational force of the armature, allowing the system to adapt to different armature weights and maintain effective braking force while using minimal energy, as the spring automatically adjusts to the load conditions
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 brake effectively arrests the armature's movement immediately upon power loss, ensuring stability and preventing unwanted movement, while allowing easy resetting and efficient release with minimal friction, suitable for testing equipment and other applications like hydraulic rams.
Implementation Method 1
The brake inhibiter 23 is an electrically actuated device such as a solenoid, in this case a rotary solenoid 23a, which in normal use when electrical power is available, holds the plate 17 in its 'off' condition
Implementation Method 2
when electrical power is not available, exerts little or no force on the plate 17 and thus allows it to pivot under the action of gravity so that the edge of the hole 19 contacts the rod 10 and causes the rod to jam as it tries to drop, also under the action of gravity
Implementation Method 3
The spring 28 provides a biasing force acting in a direction opposite to the force of gravity
Data Source
AI summary
A mechanical brake for arresting movement of the armature of a linear electric motor in the absence of electrical power comprising a pivotably mounted plate (17) having an aperture (19) for receiving a member (10) attached to the armature of the motor, and an electrically operated holding device (23) contacting a free end (21) of the plate and arranged to hold the plate in a condition to permit movement of the member while electrical power is present and to permit the plate to pivot around its second end (20) to a jamming position in the absence of electrical power.