sand jack
English
Noun
sand jack (plural sand jacks)
- (construction) A type of jack from which sand can be released gradually in small quantities when lowering something into position.
- 1950 October, “Completion of Flood-Damage Repairs, East Coast Main Line”, in Railway Magazine, page 708:
- After being rolled into position, the span had to be lowered about 4 in. on to its bearings. This was accomplished by means of sand-jacks—a simple arrangement of piston and cylinder—by which movements to very fine limits are obtained by the controlled release of sand from an opening in the base of the cylinder.
References
- “sand jack”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
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