Crankpin Diameter Checking Apparatus with Parallelogram Linkage
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Solution Overview
Problem
Existing apparatuses for checking diametral dimensions of rotating pins in grinding machines face issues with space constraints and 'bounces' of Vee-shaped reference devices, leading to unperceived detachments and potential breakages due to sliding friction and orbital motion.
Innovation Solution
A checking apparatus with a guiding mechanism featuring a constraining linkage that forms a parallelogram structure, utilizing a cam and roller mechanism to maintain contact and limit unwanted movements, ensuring accurate tracking of the pin's trajectory and preventing detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Vee-shaped reference devices are used to check diametral dimensions of rotating pins, then measurement accuracy is improved, but the device becomes vulnerable to 'bounces' and detachments during high-speed orbital motion
Solution Approach 1:
The guiding mechanism performs preliminary action by establishing a constrained circular trajectory for the Vee-shaped reference device before the measurement process begins. The parallelogram linkage structure pre-positions and pre-orients the reference device, ensuring it follows a controlled path that prevents 'bounces' and detachments during high-speed orbital motion of the pin being measured.
Solution Approach 2:
The cam and roller mechanism acts as an intermediary between the driving system and the Vee-shaped reference device. This intermediary component translates rotational motion into a controlled circular trajectory, mediating the interaction between the reference device and the rotating pin, thereby eliminating direct impact and bounce effects while maintaining measurement accuracy.
2Reliability
If guide means with extensive surfaces are used to ensure correct cooperation with the pin, then measurement reliability is improved, but the apparatus becomes too complex for space-constrained machine tools
Solution Approach 1:
The invention employs a dynamic parallelogram linkage mechanism that adapts its configuration during operation. The linkage dynamically adjusts the position and orientation of the Vee-shaped reference device to maintain optimal contact with the rotating pin throughout its orbital path, replacing static extensive guiding surfaces with a compact dynamic structure.
Solution Approach 2:
The guiding mechanism transitions from two-dimensional surface contact guidance to three-dimensional spatial trajectory control. By defining a precise circular path in space through the cam-roller-parallelogram system, the invention guides the reference device along a controlled trajectory that ensures reliable pin cooperation without requiring extensive guiding surfaces.
3Ease of operation
If the reference device moves freely towards the pin, then ease of operation is improved, but the risk of breakages and serious consequences increases due to uncontrolled movements
Solution Approach 1:
The guiding mechanism provides beforehand cushioning by pre-establishing a controlled circular trajectory for the Vee-shaped reference device. The parallelogram linkage and cam-roller mechanism act as protective constraints that cushion against uncontrolled movements, preventing the reference device from deviating into positions that could cause breakages or serious consequences during its approach to and interaction with the pin.
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 apparatus ensures accurate and reliable diametral dimension checking by maintaining contact with the pin through a controlled circular trajectory, reducing the risk of 'bounces' and breakages, while being simple and cost-effective.
Implementation Method 1
A checking apparatus with a guiding mechanism featuring a constraining linkage that forms a parallelogram structure, utilizing a cam and roller mechanism to maintain contact
Implementation Method 2
a constraining linkage (20) between the grinding-wheel slide (2) and the second coupling element (12)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus for checking the diameter of crankpins (15) of a crankshaft during the working on a grinding machine comprises a V-shaped reference device (10), a measuring device (6), and a support device (4) with a first coupling element (9) rotating with respect to a support element (5) connected to the grinding wheel slide (2), and a second coupling element (12) rotating with respect to the first one and carrying the V-shaped reference device. Guiding means with a constraining linkage (20) connected to the support device, guide the engagement of the reference device with a crankpin,. during the orbital motion of the latter, binding a part of the movement along a trajectory substantially parallel to the profile of the grinding wheel (1), while not interfering with the movements of the support device in the checking condition. A control device to bring the apparatus to the checking condition comprises a thrust element (40) that cooperates with the support device.