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Home > Quarry Articles, Links and Books > Stone Magazine > Lifting Dog for Cranes
LIFTING DOG FOR CRANES
No. 542,229-Lifting-Dog for Cranes. Application filed Sept. 7, 1894. Patented July 9, 1895, by Frank Beatie, of Leete Island, Conn.
This invention relates to an improvement in lifting-dogs for cranes, and particularly such as are adapted for raising blocks of stone which it is desirable to raise without inserting instruments of any kind for the purpose of securing a sufficient hold. The object of the invention is to produce a device in which the grip upon the stone will be made under considerable force before the lifting operation takes place.
The device consists of two jaws A B, the end of which are provided
with bearing-blocks C, which are preferalby (sic) united to the
ends of the jaws by a universal joint, 
and the bearing surfaces of the blocks are adapted to
receive removable faces D of wood or other suitable material. The
upper ends of the jaws are connected to Arms E and E' by Links F
and F'. These arms are constructed at their upper ends with
inwardly-projecting eyes G and G'. At the lower end of the arm E'
and below the link F' a link H is attached, the outer end of the
link being contracted, as shown in Figure 2. The lifting chain I is
secured to a link J, which is attached to the lower end of the arm
E below the link F. The said chain then passes upward through the
link H and through the eye G' and through a link K, which is
attached to a pulley-block of the crane, which is not shown, the
said link K being contracted at its lower end in a similar manner
to the link H, before described. The chain thence passes to and is
hooked into the eye G.
In adjusting the dogs upon a stone, the chain is drawn through the link H under a great tension as possible by hand, which tension throws the upper ends of the arms outward, as shown in full lines in Figure I. The chain then engages in the contracted portion of the link H. The chain is also engaged with the link K in the desired position for raising the stone at a proper angle. As the power is applied to raise the link K, the chain is drawn upward, and the first tendency will be to draw the upper ends of the arms forward, as shown in broken lines in Figure I. As the chain is securely attached to the lower ends of the arms by the links J H and below the point of connection between the jaws and the said arms, it necessarily follows that such strain will tend to clamp the blocks C C more securely against the stone before the actual raising takes place. By contracting the ends of the links H K their engagement with the chain at any desired point is made secure. It is apparent that various changes may be made in the manner of connecting the chain to the arms. For instance the free end of the chain might be passed downward through the eye G and engaged with the other end of the chain, or a continuous chain may be employed, as shown in Figure 4, which may be engaged by the links and through the link K of the lifting mechanism, such as arrangement being too apparent to require illustration.
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