Illustration from a carpenter book. Fig. 1: Solid Trussed Beam Fig. 2: Flitched Trussed Beam, a: Timber Strut, b: Cast Iron Strut, c: Shackle Fig. 3: Timber Strut Fig. 4: Cast Iron Strut Fig. 5: Shackle or Coupling Link for thightening up the rod Fig. 6: End of beam with cast iron shoe taking the end of the rod