{
  "$schema": "https://slfy.solidify.studio/schema/slfy-0.1.schema.json",
  "format": "slfy",
  "version": "0.1",
  "model": {
    "id": "scotch-yoke",
    "title": "Scotch Yoke Mechanism",
    "summary": "A Scotch yoke converting rotary motion into exact simple harmonic reciprocating linear motion via a slotted crosshead.",
    "units": "mm",
    "parameters": [
      {
        "id": "r",
        "label": "Crank Radius",
        "symbol": "r",
        "value": 0.06,
        "min": 0.03,
        "max": 0.09,
        "step": 0.005,
        "unit": "m"
      },
      {
        "id": "rpm",
        "label": "Crank Speed",
        "symbol": "n",
        "value": 60,
        "min": 15,
        "max": 180,
        "step": 5,
        "unit": "rpm"
      },
      {
        "id": "d_pin",
        "label": "Pin Diameter",
        "symbol": "d_p",
        "value": 0.018,
        "min": 0.012,
        "max": 0.024,
        "step": 0.002,
        "unit": "m"
      }
    ],
    "parts": [
      {
        "id": "frame",
        "name": "Base and Guide Frame",
        "material": "castIron",
        "role": "housing",
        "position": [
          0,
          -0.08,
          -0.04
        ],
        "explode": [
          0,
          -0.1,
          0
        ],
        "cut": false,
        "info": {
          "summary": "Rigid machine base with central bearing pedestal and horizontal guide bushings.",
          "role": "Anchors the crank bearing and constrains yoke motion to pure horizontal translation."
        },
        "shapes": [
          {
            "kind": "box",
            "position": [
              0,
              -0.06,
              0.04
            ],
            "sx": 0.44,
            "sy": 0.025,
            "sz": 0.16
          },
          {
            "kind": "cylinder",
            "position": [
              0,
              0.08,
              0
            ],
            "rotation": [
              1.5708,
              0,
              0
            ],
            "r": 0.045,
            "h": 0.07
          },
          {
            "kind": "box",
            "position": [
              0,
              0.02,
              0
            ],
            "sx": 0.07,
            "sy": 0.08,
            "sz": 0.07
          },
          {
            "kind": "box",
            "position": [
              -0.17,
              0.08,
              0.04
            ],
            "sx": 0.05,
            "sy": 0.06,
            "sz": 0.06
          },
          {
            "kind": "cylinder",
            "op": "subtract",
            "position": [
              -0.17,
              0.08,
              0.04
            ],
            "rotation": [
              0,
              0,
              1.5708
            ],
            "r": 0.012,
            "h": 0.06
          },
          {
            "kind": "box",
            "position": [
              0.17,
              0.08,
              0.04
            ],
            "sx": 0.05,
            "sy": 0.06,
            "sz": 0.06
          },
          {
            "kind": "cylinder",
            "op": "subtract",
            "position": [
              0.17,
              0.08,
              0.04
            ],
            "rotation": [
              0,
              0,
              1.5708
            ],
            "r": 0.012,
            "h": 0.06
          }
        ]
      },
      {
        "id": "crank",
        "name": "Crank Disc & Pin",
        "material": "steel",
        "role": "moving",
        "explode": [
          0,
          0,
          -0.12
        ],
        "cut": false,
        "info": {
          "summary": "Counterweighted crank disc with an eccentric crank pin at radius r.",
          "role": "Provides uniform rotational input that drives the slider block inside the yoke slot."
        },
        "motion": {
          "kind": "rotate",
          "axis": "z",
          "speed": "rpm / 60"
        },
        "mount": {
          "kind": "coaxial",
          "target": "frame",
          "offset": 0.035
        },
        "shapes": [
          {
            "kind": "cylinder",
            "position": [
              0,
              0,
              -0.045
            ],
            "rotation": [
              1.5708,
              0,
              0
            ],
            "r": 0.016,
            "h": 0.09
          },
          {
            "kind": "cylinder",
            "position": [
              0,
              0,
              0.008
            ],
            "rotation": [
              1.5708,
              0,
              0
            ],
            "r": "r + 0.022",
            "h": 0.016
          },
          {
            "kind": "cylinder",
            "position": [
              0,
              "r",
              0.032
            ],
            "rotation": [
              1.5708,
              0,
              0
            ],
            "r": "d_pin / 2",
            "h": 0.032
          }
        ]
      },
      {
        "id": "slider_block",
        "name": "Slider Block",
        "material": "bronze",
        "role": "moving",
        "explode": [
          0,
          0.08,
          0
        ],
        "cut": false,
        "info": {
          "summary": "Bronze bearing block journalled on the crank pin.",
          "role": "Transmits force to the vertical faces of the yoke slot while freely sliding along it."
        },
        "motion": {
          "kind": "rotate",
          "axis": "z",
          "speed": "rpm / 60"
        },
        "mount": {
          "kind": "coaxial",
          "target": "crank",
          "at": 1,
          "offset": -0.01
        },
        "shapes": [
          {
            "kind": "box",
            "sx": 0.032,
            "sy": 0.032,
            "sz": 0.02
          },
          {
            "kind": "cylinder",
            "op": "subtract",
            "rotation": [
              1.5708,
              0,
              0
            ],
            "r": "d_pin / 2",
            "h": 0.022
          }
        ]
      },
      {
        "id": "yoke",
        "name": "Scotch Yoke Crosshead",
        "material": "forged",
        "role": "moving",
        "explode": [
          0.12,
          0,
          0
        ],
        "cut": false,
        "info": {
          "summary": "Slotted crosshead with twin horizontal guide shafts.",
          "role": "Converts the rotational displacement into exact sinusoidal linear output along its guides."
        },
        "motion": {
          "kind": "oscillate",
          "axis": "x",
          "speed": "rpm / 60",
          "amplitude": "r"
        },
        "mount": {
          "kind": "against",
          "target": "frame",
          "face": "+y",
          "shift": [
            0,
            0.08,
            0.04
          ]
        },
        "shapes": [
          {
            "kind": "box",
            "position": [
              0,
              0,
              0
            ],
            "sx": 0.065,
            "sy": "2 * r + 0.075",
            "sz": 0.026
          },
          {
            "kind": "box",
            "op": "subtract",
            "position": [
              0,
              0,
              0
            ],
            "sx": 0.033,
            "sy": "2 * r + 0.034",
            "sz": 0.03
          },
          {
            "kind": "cylinder",
            "position": [
              -0.11,
              0,
              0
            ],
            "rotation": [
              0,
              0,
              1.5708
            ],
            "r": 0.011,
            "h": 0.16
          },
          {
            "kind": "cylinder",
            "position": [
              0.11,
              0,
              0
            ],
            "rotation": [
              0,
              0,
              1.5708
            ],
            "r": 0.011,
            "h": 0.16
          }
        ]
      }
    ],
    "annotations": [
      {
        "id": "stroke_dim",
        "kind": "dimension",
        "label": "Stroke",
        "magnitude": "stroke",
        "unit": "m",
        "anchor": {
          "part": "yoke",
          "at": "+y"
        }
      },
      {
        "id": "torque_in",
        "kind": "moment",
        "label": "T_in",
        "anchor": {
          "part": "crank",
          "at": "start"
        }
      }
    ],
    "calculations": [
      {
        "id": "stroke",
        "label": "Total Stroke",
        "symbol": "S",
        "formula": "2 * r",
        "unit": "m",
        "latex": "S = 2r"
      },
      {
        "id": "omega",
        "label": "Angular Velocity",
        "symbol": "\\omega",
        "formula": "2 * pi * rpm / 60",
        "unit": "rad/s",
        "latex": "\\omega = \\frac{2\\pi n}{60}"
      },
      {
        "id": "v_max",
        "label": "Peak Linear Velocity",
        "symbol": "v_{\\max}",
        "formula": "omega * r",
        "unit": "m/s",
        "latex": "v_{\\max} = \\omega r"
      },
      {
        "id": "a_max",
        "label": "Peak Acceleration",
        "symbol": "a_{\\max}",
        "formula": "omega^2 * r",
        "unit": "m/s^2",
        "latex": "a_{\\max} = \\omega^2 r"
      }
    ],
    "charts": [
      {
        "id": "kinematics",
        "title": "Scotch Yoke Displacement & Velocity vs Crank Angle",
        "x": {
          "label": "Crank Angle",
          "unit": "rad",
          "from": "0",
          "to": "2 * pi"
        },
        "y": {
          "label": "Displacement & Norm. Velocity",
          "unit": "m"
        },
        "series": [
          {
            "id": "disp",
            "label": "Displacement x(\\theta) [m]",
            "formula": "r * cos(x)"
          },
          {
            "id": "vel",
            "label": "Velocity v/\\omega [m]",
            "formula": "-r * sin(x)"
          }
        ]
      }
    ]
  },
  "view": {
    "camera": {
      "position": [
        0.45,
        0.32,
        0.55
      ],
      "target": [
        0,
        0,
        0
      ]
    },
    "extent": 0.55,
    "floorY": -0.22,
    "cut": {
      "enabled": false,
      "normal": [
        0,
        0,
        1
      ],
      "pos": 0.01
    }
  },
  "meta": {
    "generator": "Solidify (solidify.studio)",
    "license": "CC-BY-4.0",
    "created": "2026-11-10"
  }
}