Lockable Switch Mechanism With Brittle Locking Member
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Solution Overview
Problem
Existing lockable switch mechanisms made from ductile materials can deform under high loads without releasing the switch plunger, leading to reduced holding force and lack of indication when the mechanism has reached its maximum load resistance.
Innovation Solution
A lockable switch mechanism with a second locking member made from brittle material that fractures under predetermined load, breaking the conductive path and signaling failure, and featuring a profile on the switch plunger that displaces the first locking member to prevent movement from the locked to unlocked position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ductile material is used for the locking element, then the mechanism can withstand high holding forces, but the locking element may deform without releasing the switch plunger, providing no indication of maximum load resistance
Solution Approach 1:
The patent changes the material parameter from ductile to brittle, fundamentally altering the deformation behavior. The brittle locking element maintains strength while changing from gradual deformation to sudden fracture at a predetermined load, providing clear indication of maximum load resistance through circuit interruption.
Solution Approach 2:
The patent replaces the purely mechanical deformation indication with an electrical indication system. The locking element incorporates a conductive path that interrupts the electrical circuit upon fracture, substituting mechanical deformation signals with electrical signal changes for more reliable indication.
2Loss of information
If the locking element is made from brittle material that fractures under load, then immediate indication of design load limit is provided, but the mechanism complexity increases due to additional conductive path requirements
Solution Approach 1:
The locking element serves multiple functions simultaneously: it provides mechanical locking, withstands holding forces, and incorporates an electrical conductive path for circuit interruption. This multi-functionality reduces overall device complexity by combining indication functionality into the existing locking element rather than adding separate indication mechanisms.
Solution Approach 2:
The patent merges the mechanical locking function and electrical indication function into a single integrated locking element. The conductive path is embedded within the brittle locking element itself, combining structural and signaling roles into one component, thereby simplifying the overall device architecture.
3Reliability
If the locking element deforms under load without fracturing, then the mechanism maintains its locking function, but the holding force is considerably reduced without providing any indication
Solution Approach 1:
The patent designs the brittle locking element with a predetermined fracture load that is set before actual use. This preliminary determination of the failure point ensures that the element will fracture at a known, controlled load level, providing advance warning before complete failure and allowing for preventive maintenance or shutdown.
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 mechanism provides immediate indication of reaching the design load limit by breaking the circuit, ensuring safety and reliability by maintaining the holding force until fracture, unlike ductile materials that deform without tripping the switch.
Implementation Method 1
a first locking member which is spring biased against a surface of the switch plunger
Implementation Method 2
the second locking member made from brittle material that fractures under predetermined load, breaking the conductive path
Implementation Method 3
the surface of the switch plunger against which the first locking member is biased defining a profile arranged such that movement of the switch plunger from the second to the first position causes the profile to displace the first locking member
Implementation Method 4
the second locking member, when in the locked position, provides a conductive path between said pair of electrical contacts
Data Source
AI summary
A locking switch assembly includes a cam, a plunger, and a locking mechanism. The cam is rotatably attached to a frame assembly and an end of the plunger is constructed to follow a contour of the cam. The plunger is movable between a plunger first position and a plunger second position. A pin is biased against the plunger and movable between a pin first position and a pin second position and locks the plunger in the plunger second position when the pin is in the pin second position. A breakable arm prevents movement of the plunger from the plunger second position to the plunger first position unless a force above a selected amount is applied to the cam when the plunger is in the plunger second position.