294 



MACHINE FOR HAND LABOUR. 



and rear of the wheel two steps on which the men stand as they go on or 

 off the wheel. 



tv. The wheel 4 feet in diameter, the steps 3| feet long 8 inches wide, made 

 of 1^ inch plank. The ends of the wheels are formed of two thicknesses 

 of inch plank placed crosswise, the inside being grooved to receive the 

 steps which are placed about 8 inches apart. The axle of the wheel is 

 10 feet 6 inches long and 8 inches in diameter, the portion round which 

 the rope winds is enlarged, so as to suit the force employed on the wheel, 

 or the weight to be raised, by nailing on strips of plank, over which a 

 few turns of old rope may be placed to prevent the slipping of the chain. 



To prevent confusion, only one crane (or arm) is represented in this figure. 



The crane post is represented as turning on two iron pivots in pieces s, s, 

 one bolted to the principal post e, and the other spiked to the base. The 

 crane post is 6 inches square. 



a. The crane jib, 7 feet 6 inches long, 6 by 7 inches. 



b. The strut to the jib, 8 feet 6 inches long, 4 by 6 inches. Near the ex- 

 tremity of the jib an iron sheeve is fixed over which the chain passes. 



c. Is a three-quarter inch rod of iron secured to a by means of a staple, 

 and having a hook at the other end, which drops into a staple at i. This 

 rod serves the double purpose of a stay and a guide, by which (when 

 unhooked) the arm is drawn to one side for the purpose of landing the 

 box. When fixed as represented in the drawing, it serves to retain the 

 crane in its proper position. When the box is raised the rod is unhooked, 

 and by means of it the box is landed. ^ 



Fig. 2. 



J 



Figure 2 is a front view, showing the relative position of the cranes, which 

 are represented as turned aside. The chain is seen winding around the 

 axle. It is evident that the men must pass to the opposite side of the 

 wheel as each box is drawn up. 



//. Represents 2. views of the boxes, which are square and may be each 

 about 21 inches every way. They will then contain nearly 6 cubic feet 

 each. They are suspended by two pins, placed a little below and to one 



