CAPSTAN 



715 



Mr. Hindmarsh, of Newcastle, obtained a patent, in February 1827, for a con- 

 trivance to enable a capstan or windlass to be occasionally worked with increased 

 mechanical advantage. With this view, he placed toothed wheel-work, partly in the 

 drum-head of the capstan, and partly in the upper part of the barrel, upon which the 

 cable is coiled and uncoiled in successive portions. 



The drum-head, and also the barrel, turn loosely upon a central spindle, independently 

 of each other, and are connected together either by the toothed gear, or by bolts. On 

 raising or withdrawing the connecting pinion from the toothed wheels, and then 

 locking the drum-head and barrel together, the capstan works with a power equal 

 only to that exerted by the men at the capstan-bars, as an ordinary capstan ; but on 

 lowering the pinion into gear with the wheel work, and withdrawing the bolts which 

 locked the drum-head to the barrel, the power exerted by the men becomes increased in 

 proportion to the diameter and number of teeth in the wheel and pinions. 



Fig. 422 is the external appearance of this capstan. Fig. 421 a horizontal view of 

 the toothed gear at the top of the barrel. The- barrel, with the whelps a a, turn 

 loosely upon a vertical spindle fixed into the deck of the vessel. 

 The drum-head b also turns loosely upon the same spindle. 

 The circular frame cc, in fig. 421, in which the axes of the 

 toothed wheels ddd are mounted, is fixed to the central spindle. 

 The rim e e e, with internal teeth, is made fast to the top of the 

 barrel, and the pinion/, which slides upon the spindle, is con- 

 nected to the drum-head. 



When it is intended to work the capstan with ordinary 

 power, the pinion /is raised up into the recess of the drum-head, 

 by means of a screw g, fig. 422, which throws it out of gear with 

 the toothed wheels, and it is then locked up by a pin z : the 

 bolts h h are now introduced, for the purpose of fastening the 

 drum-head and barrel together, when it becomes an ordinary 

 capstan. 



But when it is required that the same number of men shall 

 exert a greater power, the bolts h are withdrawn, and the 

 pinion /lowered into gear with the toothed wheels. The rota- 

 tion of the drum-head, then carrying the pinion round, causes it 

 to drive the toothed wheels ddd; and these working into the 

 toothed rim ee, attached to the barrel, cause the barrel to revolve 

 with au increasing power. _______ 



Thus, under particular circumstances, a smaller number of f l ^]) , *g) 



men at the capstan or windlass (which is to be constructed upon [ i 



the same principle) will be enabled to haul in the cable and 



anchor, or warp off the vessel, which is an important object to be effected. 



In 1819, Captain Philips obtained a patent for certain improvements in capstans, a 

 part of which invention is precisely the same as this in principle, though slightly varied 

 in its adaptation. 



James Brown, ship-rigger, in his capstan, patented in 1833, instead of applying the 

 moving power by handspikes, having fixed two rims 

 of teeth round the top of the capstan, acts upon 

 them by a rotatory worm, or pinions turned by a 

 winch. 



Fig. 423 is an elevation of this capstan, and/*?. 

 424 is a horizontal top view, a is an upright shaft, 

 fixed firmly to the deck, serving as an axle round 

 which the body of the capstan revolves. A frame c, 

 fixed to the top of a stationary shaft a, above 

 the body of the capstan, carries the driving appa- 

 ratus. 



The upper part of the body of the capstan has a 

 ring of oblique teeth d, formed round its edge ; and I" ' 



above this, on the top of the capstan, is a ring of bevel teeth e. A horizontal shaft 

 /, mounted in the top frame c, has a worm or endless screw, which takes into the 

 teeth of tho ring d ; and a short axle g, having its bearings in tho central shaft a, 

 and in the frame c, carries a bevel pinion, which takes into tho bevel teeth of tho 

 ring e. 



Tho bearings of the shaft /, in the top frame, are in long slots, with angular 

 returns, something like tho fastening of a bayonet, which is for the purpose of 

 enabling tho shaft to be readily lifted in and out of gear with tho teeth of the ring 

 d ; the outer bearing of the axle g of tho bevel pinion is also supported in the 

 frame c, in a similar way, in order to put it in and out of gear with the teeth of tho 



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