Spindle grips, [Nos. 917, 918], [919].
There are numerous forms of three and four-jaw chucks, both with universal or centering motions, and with independent jaws. See Horton’s, Cushman’s, the Sweetland, Pratt and Whitney’s, Westcott’s and others, chiefly American.
These are various combinations of the scroll ([No. 1384]) and screw jaws, as in the ordinary dog chuck. See also [Nos. 1378] and [1381].
Section 29.—CUSHIONING.
For checking the impact of a blow, or more generally the momentum of a heavy moving part of a machine. The devices in use comprise (a) springs, see [Section 80]; (b) air cylinder, see [No. 1480]; (c) pistons driven by elastic fluids, such as steam and air, can be cushioned by imprisoning a portion of the fluid at each end of the cylinder; (d) brakes of various kinds, see [Section 5].
[519]. Hydraulic cushion. The descending ram, by its tapered end, closes gradually the discharge outlet for the water.
Hydraulic buffer stops are constructed on this principle.
[520]. Cushioning device, at the upper end of a steam-hammer cylinder. Should the piston pass the exhaust holes, the steam above is imprisoned, and checks the piston without shock.