1 SGO. 



NEW ENGLAND FARMER. 



481 



BATES'S STUMP AjNTD BOCK LIFTEK. 



We present our readers this week a cut and 

 description of this machine, which, for simplicity 

 of construction and economy of power, exceeds 

 any machine for the purpose which has ever come 

 under our notice. It is the invention of Mr. Ca- 

 leb Bates, of Kingston, Mass. 



It consists of a rocking head A, supported by 

 knife-edge trunions B B (like the bearings of a 

 scale-beam,) resting in the eyes of the hanger.^ 

 E E. A double rack-bar, D D, passes through 

 the centre of the rocking-head, with a hook at its 

 lower end. The levers, F F, slip into square 

 sockets in the rocking head to be thrown down 

 when the machine is not in motion. Within the 

 head is a pair of pawls, in the form of square 

 links, crossing each other outside of the rack-bar. 

 Clearly shown in Fig 2. 



There are also guides to the rack-bar, not 

 shown. The whole is suspended in a tripod of 

 poles or joists, fourteen feet long. Two pieces 

 of spruce joist, four by five inches square, with a 

 strap of board bolted on them ; and one stick four 

 by six inches, having iron braces hooked into it 

 from the others, as shown above the machine. A 

 pin in each leg to carry it by, and strongly cleat- 

 ed pieces of plank to throw under the feet, and it 

 is ready for use. 



When the hook is fast to the object to be lift- 

 ed, the operators work the levers up and down, 

 and the pawls engaging alternately with the racks 

 on opposite sides of the bar keep it in continuous 

 motion. As the head rocks, the relative position 

 of the working parts changes, producing a pro- 

 gressive power. For, as the operating pawl ap- 

 proaches its culminating points, its journals ap- 

 proach a plane which intersects the points of con- 

 tact with the rack and bearing edge of the 

 trunions ; the lifting power increasing from 

 the commencement to the termination of each 

 vibration. 



To reverse the action of the machine, a 

 tongue of steel, G, is tipped up. Then with 

 the same vibrations of the lever, the weight 

 will descend gently, with the same speed that 

 it rises, until the hook is loose ; then, grasp- 

 ing the rack-bar with one hand, with the 

 other spread the pawls, and the bar drops to 

 any point, or entirely out if desired. 



The two men stand sixteen feet apart, and 

 exert the force of two hundred men on the 

 rock, stump, or other weight to be lifted. 



