nhf/touhou/houjuu_nue/joints.py

@@ -305,13 +305,28 @@ class ShoulderJoint(Model):
     angle_neutral: float = -15.0
     angle_max_deflection: float = 65.0
 
+    spool_radius: float = 14.0
+    spool_groove_depth: float = 1.0
+    spool_base_height: float = 3.0
+    spool_height: float = 5.0
+    spool_groove_inset: float = 2.0
+
     def __post_init__(self):
         assert self.parent_lip_length * 2 < self.height
+        assert self.spool_groove_depth < self.spool_radius < self.torsion_joint.radius_rider - self.child_core_thickness
+        assert self.spool_base_height > self.spool_groove_depth
 
     @property
     def radius(self):
         return self.torsion_joint.radius
 
+    @property
+    def draft_length(self):
+        """
+        Amount of wires that need to draft on the spool
+        """
+        return (self.spool_radius - self.spool_groove_depth / 2) * math.radians(self.angle_max_deflection)
+
     def parent_lip_loc(self, left: bool=True) -> Cq.Location:
         """
         2d location of the arm surface on the parent side, relative to axle
@@ -416,7 +431,10 @@ class ShoulderJoint(Model):
 
     @target(name="parent-bot")
     def parent_bot(self) -> Cq.Assembly:
-        return self.parent(top=False)
+        result = (
+            self.parent(top=False)
+        )
+        return result
     @target(name="parent-top")
     def parent_top(self) -> Cq.Assembly:
         return self.parent(top=True)
@@ -430,6 +448,36 @@ class ShoulderJoint(Model):
         joint = self.torsion_joint
         return self.height - 2 * joint.total_height + 2 * joint.rider_disk_height
 
+    def _spool(self) -> Cq.Workplane:
+        """
+        Generates the spool piece which holds the line in tension
+        """
+        t = self.spool_groove_depth
+        bulk = Cq.Solid.makeCylinder(
+            radius=self.spool_radius,
+            height=self.spool_height,
+        ).located(Cq.Location((0, 0, self.spool_base_height)))
+        base = Cq.Solid.makeCylinder(
+            radius=self.spool_radius - t,
+            height=self.spool_base_height,
+        )
+        hole_x = self.spool_radius - (t + self.spool_groove_inset)
+        slot = Cq.Solid.makeBox(
+            length=t + self.spool_groove_inset,
+            width=t,
+            height=self.spool_base_height,
+        ).located(Cq.Location((hole_x, -t/2, 0)))
+        hole = Cq.Solid.makeBox(
+            length=t,
+            width=t,
+            height=self.spool_height + self.spool_base_height,
+        ).located(Cq.Location((hole_x, -t/2, 0)))
+        centre_hole = Cq.Solid.makeCylinder(
+            radius=self.torsion_joint.radius_axle,
+            height=self.spool_height + self.spool_base_height,
+        )
+        return bulk.fuse(base).cut(slot, hole, centre_hole)
+
     @target(name="child")
     def child(self) -> Cq.Assembly:
         """
@@ -512,6 +560,8 @@ class ShoulderJoint(Model):
         loc_rotate = Cq.Location((0, 0, 0), (1, 0, 0), 180)
         loc_axis_rotate_bot = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_bot + self.angle_neutral)
         loc_axis_rotate_top = Cq.Location((0, 0, 0), (0, 0, 1), self.axis_rotate_top + self.angle_neutral)
+        spool_dz = self.height / 2 - self.torsion_joint.total_height
+        spool_angle = 180 + self.angle_neutral
         result = (
             Cq.Assembly()
             .add(core, name="core", loc=Cq.Location())
@@ -523,6 +573,8 @@ class ShoulderJoint(Model):
                  loc=Cq.Location((self.child_guard_ext, 0, dh)))
             .add(lip, name="lip_bot",
                  loc=Cq.Location((self.child_guard_ext, 0, -dh)) * loc_rotate)
+            .add(self._spool(), name="spool",
+                 loc=Cq.Location((0, 0, -spool_dz), (0, 0, 1), spool_angle))
         )
         return result