Specification of John Wallace : ships' safety hearth.

  • Wallace, John.
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Specification of John Wallace : ships' safety hearth. Source: Wellcome Collection.

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    Wallaces Improvements in the Safety Hearth. -- - - - - - - - - - - - ~ - - ~ - - - - - - - - - - —~ the jack are fixed, more clearly seen in the bird’s-eye view, Figure 20; and in this Figure the pivot rest 5 is attached at its extreme end to keep it in its place; 7 is an oil box, the end of which is only seen in this Figure resting upon the bar 6, but it is best seen in Figure 3. Figure 3 is an end view, in 5 which 6 is still farther explained; it is here seen lengthways, and is turned down at each end, and secured to the cylinder by two screw bolts, as indicated by the Drawing 7, the oil box, already referred to; it is made of cast iron or other suitable material, and is supposed to have the side next the observer removed, in order to shew how the upright axis moves in the bottom of it in a 10 centre ; it is introduced into the side of the cylinder by a hole cut for it, and projects out from the side, and it also projects at the other end a little beyond the centre of the cylinder, for the purpose of fixing a piece of metal 13, through which the upright axis descends; and this piece of metal 13 acts as a guide in case (if by any accident) the axis should come out of the centre. 15 8 is the wheel acted upon by the endless screw 3, and having at the end of its axis or pulley, best seen in Fig. 1; opposite this wheel the pivot rest is best seen, being fixed obliquely that the chain may not be interrupted, which it would be if placed perpendicularly; 9 is another oil box, of a cylindrical form, to contain oil to lessen the friction on the axis; 10 is an arm for the upright 20 axis to work in; it is bent down a little into the oil box to come in contact with the oil, and is fixed on another arm 11 by a screw nut; 11 is an upright arm, attached to the oil box by a screw bolt or other means; 12 is another arm for fixing the other end of the arm 10, and it is also fixed to the oil box in the same manner as 11. Fig. 20 is a bird’s-eye view of the] cylinder, in 25 which the position of the wheel 8 is seen fixed on its axis ; this axis is passed through a hole in the side of the cylinder, and the other end moves in a piece of iron fixed on the inside of the oil box 7; 2 is the centre of the upright axis; the relative position of the iron arm 6, the axis 4, and the pivot rest 5, and the pulley, are here seen. Fig. 21 is the pivot rest, SO having a square hole at the one end for taking on to the bar 6, and a round hole at the other end for the axis 4 to move in. In this Figure the arm 6 is also represented as passed through the cylinder by a hole made for the purpose; it is made strong for holding the pivot rest firmly. I may here state that I occasionally use a cover for the brass wheel and spiral or endless screw, 35 which cover rests upon or is attached to the oil box; I have also a cover, which is applied over the projecting end of the oil box, with a space between the said cover and the oil box for the admission of cool air into the jack apparatus to prevent it as much as possible from being dirtied and injured by