▪ I. tappet
(ˈtæpɪt)
Also 8–9 tapit, 9 tapet, tappit, tabbot.
[app. f. tap v.2 + -et1; but the use of the suffix is abnormal. Cf. mod.F. tapette a flat piece of wood for driving in corks.]
A projecting arm or part in a machine, which by the movement of the latter comes intermittently into contact with another part, so as to give or receive motion.
| 1745 Specif. Kay & Stell's Patent No. 612 There are likewise fixed in the sliding beam or hollow rowler, at proper distances, sundry tapits. 1824 R. Stuart Hist. Steam Engine 114 The pins or tappets [are] fixed on the plug⁓frame (or tappet rod)..: at the ascent or descent of these pins, they strike on the ends of the levers or spanners..connected with the valves,..and open or shut them. 1831 J. Holland Manuf. Metal I. 241 As the wheel shaft revolves, the tappits successively strike the hammer tail. 1839 Ure Dict. Arts, etc. 1287 T is the shaft of the eccentric tappets, cams, or wipers, which press the treddle levers alternately up and down. 1870 J. M. Nutter in Eng. Mech. 4 Mar. 610/2 Much depends upon the description of loom and make of tabbots in treading motion. 1907 Westm. Gaz. 28 Nov. 4/1 The inclined valves and new valve tappets..mark it [a motor car engine] with a distinctiveness all its own. |
b. attrib. and Comb.; appositive, ‘that is a tappet’, as tappet-arm, tappet-lever, tappet-pin, tappet-plate; ‘of a tappet or tappets’, as tappet action, tappet-bevel, tappet-bowl, tappet motion; ‘having or worked by a tappet or tappets’, as tappet-port, tappet-rod, tappet-valve, tappet-wheel.
| 1824 Tappet rod [see above]. 1837 H. Stansfeld in Civil Eng. & Arch. Jrnl. I. 54/2 Certain Machinery of a Tappet and Lever Action. 1839 Ure Dict. Arts, etc. 1287 Heddle leaves, actuated by the tappet wheels upon the axis Q. 1895 Model Steam Engine 46 Simply altering the position of the tappet lever by means of two screws. 1908 Westm. Gaz. 28 Apr. 4/2 The valve-stems may be lengthened or the tappet-ports enlarged. |
▪ II. tappet
16th c. var. toppet, basket.
▪ III. tappet, -ett, -ette
variants of tapet.