Caster Trip Cam with Independent Tappets for Reduced Switching Force
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Solution Overview
Problem
Existing casters require higher switching forces to achieve braking and direction lock actions, and often require simultaneous displacement of both tappets, which can be cumbersome and inefficient.
Innovation Solution
The caster design features two tappets arranged transversely with different cam surfaces on a trip cam, allowing for independent displacement of each tappet to achieve braking or direction lock without increasing switching forces, using a roller bearing mechanism to reduce effort and incorporating a second braking part for interlocking friction lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single tappet is used for both braking and direction lock functions, then the device complexity is reduced, but the switching force required increases
Solution Approach 1:
The single tappet is segmented into two functionally independent tappets: a first tappet for braking action and a second tappet for direction lock. This segmentation allows each tappet to be actuated independently with lower forces, as each only needs to perform one function rather than both functions simultaneously.
Solution Approach 2:
The trip cam is designed with two different cam surfaces that can actuate either tappet independently. This multi-functional design allows a single trip cam mechanism to control both braking and direction lock functions by selectively engaging with the appropriate cam surface and tappet combination.
2Reliability
If both tappets are displaced simultaneously to achieve braking and direction lock, then the locking function is complete, but the ease of operation deteriorates
Solution Approach 1:
The locking function is segmented into two independent sub-functions: braking (first tappet) and direction lock (second tappet). Each sub-function can be activated independently by displacing only the relevant tappet, improving operational efficiency while maintaining complete locking reliability when both are engaged.
Solution Approach 2:
The system allows dynamic selection of which tappet to displace based on the desired function. The trip cam can be rotated to engage with either the first or second cam surface, enabling flexible and efficient operation where only the necessary tappet is actuated for each specific task.
3Device complexity
If the same cam surface is used for both tappets, then the device complexity is reduced, but the adaptability deteriorates
Solution Approach 1:
The trip cam features two different cam surfaces with distinct local qualities: a first cam surface configured to actuate the first tappet for braking, and a second cam surface configured to actuate the second tappet for direction lock. This local differentiation enables versatile control of different functions while maintaining a unified trip cam structure.
Solution Approach 2:
The two cam surfaces are designed asymmetrically with different geometries optimized for their respective tappets and functions. This asymmetry allows each surface to be tailored for its specific function, providing adaptability and versatility in controlling braking and direction lock independently.
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
This design reduces switching forces required for braking and direction locking, allowing for efficient operation with lower effort and enabling independent control of each function, enhancing the overall braking properties of the caster.
Implementation Method 1
the trip cam has two cam surfaces (21, 22) which are each assigned to one of the tappets (12, 13)
Implementation Method 2
The trip cam may act on one or both tappets by means of a roller bearing
Implementation Method 3
the braking device has a first braking part for friction-locking action on the running wheel
Data Source
AI summary
A caster includes a running wheel, a fork and an assembly journal, wherein the fork is pivotable in relation to the assembly journal and a braking device is arranged in the fork and can be displaced into the braking position via a tappet actuated by a trip cam. A direction lock can be set without a braking action on the running wheel. Two tappets are movable independently of each other, wherein only the direction lock without a braking action can be set via one of the tappets. Another caster includes a running wheel, a fork and an assembly journal, wherein a braking device is provided in the fork and can be displaced into the braking position via a trip cam. The braking device has a first braking part for friction-locking action on the running wheel and a second braking part for the interlocking lock of the running wheel.