[Known since 15th (or 14th) c. Also in Du. (since 16th c.) klampe, now klamp, ‘clamp, cleat,’ LG. and mod.Ger. klamp, klampe, in HG. dial. klampfe; on WGer. type *klampa wk. fem., and *klampo wk. masc., belonging to a stem *klamp-, supposed to be a by-form of *klamb-, klamm-: see CLAM sb.1, with which this word is to a certain extent synonymous. From the same stem, MHG. had klampfer, and mod.HG. dial. klampfer, klamper (Bav.), in sense of modern Ger. klammer a clamp. Whether the Eng. word was adopted from LG. or Du., or was a native derivative which happens not to be known in OE. or ME. up to the 14th c., is uncertain.]
1. A brace, clasp, or band, usually of iron or other rigid material, used for giving strength and support to flexible or movable objects, or for fastening two or more things securely together. In many technical senses:
e.g., A bar of iron for binding together stones in a building, also a metal clasp or rivet for broken china-ware, etc.; a piece of wood attached to or inserted into another to strengthen it and prevent warping.
a. 1400–50. [see 4].
1476–8. Churchw. Acc. St. Andrew’s Hubbard, in Brit. Mag., XXXII. 31. Item, for ij Clampys of Iren for pewes … iijd.
1490. Churchw. Acc. St. Dunstan’s, Canterb. Payde for fettyng home the clampis for the baners jd.
1535. Coverdale, Ex. xxxvi. 29. Ioyned with his corner borde from vnder vp, and aboue vpon the heade to come together with a clampe.
1551. Recorde, Cast. Knowl. (1556), 54. Twoo small clampes of thinne brasse plate.
1823. P. Nicholson, Pract. Build., 221. Clamp.—A piece of wood fixed to the end of a thin board … [to] prevent it from casting.
1833. Arnott, Physics, II. I. 69. Where the stones of a building are held together by clamps or bars of iron … the expansion in summer of these clamps will force the stones apart.
1877. W. Thomson, Voy. Challenger, I. i. 22. A light india-rubber clamp … sufficiently strong to grasp and retain anything light.
1877. Bryant, Odyss., V. 300. He bored the beams, and … made them fast with nails and clamps.
1879. Sala, in Daily Tel., 26 Dec. One of the iron clamps of a trunk.
1879. Thomson & Tait, Nat. Phil., I. I. § 149. Attach the two sheets together by very slight paper or muslin clamps gummed to them along the common curved edge. Ibid., § 198. A geometrical clamp is a means of applying and maintaining six mutual pressures between two bodies touching one another at six points.
b. Ordnance. The cap-square of a gun.
1769. Falconer, Dict. Marine (1784), Clamps are also small crooked plates of iron, fore-locked upon the trunnions of the cannon, to keep them steady in their carriages at sea. Ibid., I. 4. The cap-squares, otherwise called clamps.
c. fig.
1860. Emerson, Cond. Life, Fate, Wks. (Bohn), II. 322. A king on the top; with clamps and hoops of castles, garrisons, and police.
1862. S. Lucas, Secularia, 103. A series of rules,… which rested, sustained and suspended, as it were, by the clamp of a common religious profession.
2. A name of various appliances, tools or instruments with opposite sides or parts that may be screwed or otherwise brought together, so as to seize, hold, compress or pinch anything:
e.g., with Joiners, an appliance of this nature in which articles are firmly held while being formed, or are compressed together while their glue joint is drying: a check for a vice, made of lead, copper, or other soft material to grasp without bruising, etc. = CLAM sb.1 2.
1688. R. Holme, Armoury, II. 187/2. Clamps are Pinchers with which Foxes and Badgers are taken out of the Earth.
1727. Bradley, Fam. Dict., s.v. Badger-hunting, The Clamps, whereby the Badger may be taken out alive, to make Sport therewith afterwards.
1867–77. G. F. Chambers, Astron., Voc. 913. Clamp, a contrivance for making fast for a time certain parts of an instrument which are ordinarily moveable.
1869. E. A. Parkes, Pract. Hygiene (ed. 3), 31. An india-rubber tube, which is to be closed by a clamp.
1876. Foster, Phys., I. iv. (1879), 127. To place a clamp on the vessel on the proximal side of the ligature.
1882. Syd. Soc. Lex., Clamp, an instrument employed for the purpose of compressing the pedicle of a tumour, before its removal by the knife … it consists essentially of two metal blades capable of being approximated and fixed by a screw movement.
† b. pl. Claws, ‘clutches’; = CLAM sb.1 3. Obs.
1548. Forrest, Pleas. Poesye, 582. And what hee onys into his Clampis catche maye The poore man theereof no peece shal come bye.
3. Naut. in various senses.
a. One of the thick planks in a ship’s side below the shelf-piece which support the ends of the deck-beams; b. a piece of timber applied to a mast or yard to prevent the wood from bursting; c. a plate of iron that can open or shut so as to confine a spar; d. a one-cheeked block, etc.
1626. Capt. Smith, Accid. Yng. Sea-men, 9. For clamps, middle bands and sleepers, they be all of 6. inch planke for binding within. Ibid. (1627), Seaman’s Gram., ii. 6. Your risings are aboue the Orlop as the Clamps are vnder it.
1748. Anson, Voy., II. iv. 158. Two standards were broken, as also several clamps.
1794. Rigging & Seamanship, I. 164. Clamp, a crooked iron plate, fastened to the after-end of the main-cap of snows, to secure the trysail-mast.
1867. Smyth, Sailors’ Word-bk., Clamp, a one-cheeked block; the spar to which it is fastened being the other cheek.
† 4. In other obs. uses: see quots. At a clamp has been explained as ‘at a pinch,’ i.e., ‘in a moment,’ but this is doubtful.
a. 1400–50. Alexander, 3263. All werldly þing, I-wis, þurȝe þe will of oure lord, In-to þe contrare clene is at a clamp turned.
1576. Gascoigne, Steele Gl. (Arb.), 68. How ere their gownes, be gathered in the backe, With organe pipes, or old king Henries clampe.
1674. Ray, N. Country Wds., 14. Clamps, irons at the ends of Fires, to keep up the Fewel. In other places called Creepers or Dogs.
1746. Miles, in Phil. Trans., XLIV. 56. A Clamp of Iron, such as is used for heating Box-Irons for smoothing Linen-Clothes.
5. attrib. and in Comb., as clamp-ring, -treatment (in Med.), -tube; clamp-irons, andirons; clamp-nail, a large-headed nail for fastening iron clamps; clamp-plate (Ship-building), an iron plate, generally of circular shape, serving to unite two bodies; clamp-screw: see quot.
1742–1800. Bailey, *Clamp-irons, at the Ends of Fires to keep up the Fewel, called also Creepers, or Dogs [in earlier edds. clamps.] Ibid. (1721–1800), *Clamp-nails.
c. 1850. Rudim. Navig. (Weale), 134. Clamp nails are short stout nails with large heads, for fastening iron clamps.
1869. Sir E. J. Reed, Shipbuild., xii. 239. Additional strength is often given to the upper part of a ship by means of rail and *clamp-plates.
1879. S. Highley, in Cassell’s Techn. Educ., IV. 257/2. The *clamp-ring attached to each form of lamp.
1831. Brewster, Optics, xii. 102. Three pair of *clamp screws.
1874. Knight, Dict. Mech., I. 560/2. Clamp-screw, a joiner’s implement, on the bench, or to be attached to the work, for holding work to a table, or two pieces together.
1879. S. Highley, in Cassell’s Techn. Educ., IV. 257/2. Two sharp edges were left to bite on the adjusting *clamp-tube.
