The 'Oldham Coupling' transmits power between shafts that are parallel and offset from each other. A 'floating' disc, in the middle of the coupling, has a raised rib on each face. Each rib is perpendicular(⊥) to each other. The raised ribs engage with slots in flanges on the input and output shafts. The Oldham Coupling is a kinematically-defined chain that is built with a:
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The video shows an 'Oldham Coupling'. 'Input': The Input Crank – the Motion-Part 'Output': The Output Crank – rotates at the same constant speed. 'Middle Disk': This transmits power/torque from the Input to the Output Crank. |
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A kinematic-chain has a Motion-Part. as an input.
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We now want to add a Dyad. Dyads ALWAYS have two Parts and three Joints. Never forget this!
Dyad: Part-2 and Joint-3 The output of the Oldham Coupling rotates.
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Dyad: Part-1 and Joint-1
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Dyad: Joint 3 ...Preparation
Note: The +X-axis is the direction you drag to the add the Line. |
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Dyad: Joint 3
To add the Slide-Joint:
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The Oldham Coupling is Complete. You can add Extrusions to the Parts to show the coupling as a Solid model.
Note: Part-1 (the Output-Part) may be 180º to the direction it is in this image. The direction of the +X-axis of the Output-Part is the same direction Line (start-Point to the end-Point) you add to make the Slide-Joint. The +X-axis of a Line is the same as the direction you drag your mouse-pointer to add the Line. |
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The Kinematics-Tree shows the Motion-Part - Rocker (Crank) and the new R-R-P Dyad. Note: this is the same Dyad as the Scotch Yoke! Oldham Coupling, you connect the R Joint to the Base-Part and the P-P Joints are internal to the kinematic-chain. Scotch-Yoke, you connect the P Joint to the Base-Part, and the R-P Joints are internal to the mechanism. |