Instrument fitted to a beam's end to raise it with a lever
A rack-and-roller tool to begin lifting a heavy beam
The main drawing shows a heavy cylindrical beam resting on rollers, with a vertical toothed rack and a long lever arm carrying a plumb-line; a smaller wedge-shaped tool appears at upper right. The notes explain that this instrument is set into the head of the beam so a lever can be applied to raise it. Once the lever has lifted the beam high enough for the device to slip beneath its middle, the beam is propped and the instrument placed at its center to complete the lift.
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Rack-and-lever tool set into the beam's head
The instrument is made to be fitted into the front, or head, of the beam so that a lever can be attached to it and the beam raised. A vertical toothed rack and a long arm with a plumb-line drive the lifting action.
Starting, propping and completing the lift
The tool gives the beginning to the mode of raising shown opposite: first the lever lifts the beam, then when its middle is high enough off the ground the device slips beneath it. The beam is propped, the instrument set at its center, and the lift is carried through.