<< Click to Display Table of Contents >> Navigation: Getting Started Tutorials - MechDesigner > Tutorial 2A: Four-bar Kinematic-Chains > Step 2.8: Model a 'Pin in a Straight Slot' |
You may think a Pin-in-a-Slot is a special type of joint. |
![]() Three representations of a 'Pin-in-a-Slot'. |
The mechanical-design of a Pin-in-a-Slot might be similar to Diagram A, in which we see two Parts : •Part •Part However, the kinematic-design of a Pin-in-a-Slot is always three Parts. Diagram B shows a different mechanical configuration, with three Parts: •Part •Part •Part It helps me to imagine that Part Diagram C shows a system that is a similar construction to Diagram B. Diagram C shows the Pin-Joint is offset to one side of the Slide-Joint. All three designs use the same kinematic-construction - they use the R-R-P Dyad. |
Video: 'Pin in a Slot'. E.g Geneva Replacement.
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Dyad ONLY - Note: This shows
STEP 1: Draw a Line† in Part Add dimensions and constraints to the Line. It will be the Slide-Rail. STEP 2: Add a STEP 3: Join Part Part STEP 4: If necessary, edit Part STEP 5: Join, with a Pin-Joint Notes: † You can add a CAD-Line in a Part ‡ STEP 4 may not be necessary as you can use the start-Point or end-Point of the CAD-Line in Part |
The Pin-in-a-Slot is actually two joints (of the three total joints) in a Dyad. In the Dyads we describe below, the letters R-P represent the two joints. •The R is a Pin-Joint - R for Revolute-Joint, which is the kinematic-term for Pin-Joint. •The P is a Slide-Joint - P for Prismatic-Joint, which is the kinematic term for Slide-Joint. When you add a third joint, which may be a Slide-Joint(P) or a Pin-Joint(R), the Dyad is complete. You can also join the Dyad to a Rocker or a Slider. Thus, it is possible to build eight different kinematic-chains. Configurations: 1 & 2: RP+R + Rocker OR RP+R + Slider. The Dyad is an RPR Dyad. 3 & 4: RP+P + Rocker OR RP+P + Slider. The Dyad is an RPP Dyad. 5 & 6: R+RP + Rocker OR R+RP + Slider. The Dyad is an R-R-P Dyad. 7 & 8: P+RP + Rocker OR P+RP + Slider. The Dyad is a PRP Dyad. Remember also, it is possible for each Dyad to have a maximum of four different closures. See Change Dyad Closure. |
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Configuration 1 (See Step 2.7) This is a Rocker and an R-P-R Dyad Join Part Join Part Join Part Join Part (A Motion-Dimension FB identifies the Part we will move with a specified motion. The motion-values at the input-connector to the Motion-Dimension give the rotation to the Part |
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Configuration 2 This is a Rocker and an R-R-P Dyad (or P-R-R if you prefer to start from the Motion Driven Joint) Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the rotation to the Part Part Part Part |
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Configuration 3 (See Step 2.6) This is a Rocker and an R-P-P Dyad Join Part Add a Line to Part Join Part Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the rotation to the Part |
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Configuration 4 This is a Slider and an R-R-P Dyad (or a P-R-R if you prefer to start from the Driven Joint) Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the displacement to the Part Add a Line to Part Join Part Join Part |
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Configuration 5 This is a Slider and an P-R-P Dyad Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the displacement to the Part Add a Line to Part Join Part Join Part |
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Configuration 6 This is a Rocker and an P-R-P Dyad Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the rotation to the Part Add a Line to Part Join Part Join Part |
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Configuration 7 This is a Slider and an R-P-R Dyad Join Part Add a Line to Part Join Part Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the displacement to the Part |
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Configuration 8 This is a Slider and an R-P-P Dyad Join Part Add a Line to Part Join Part Join Part (A Motion-Dimension FB identifies Part The motion-values at the input-connector to the Motion-Dimension give the displacement to the Part |