a crank is an arm attached at a right angle to a rotating shaft by which reciprocating motion is imparted to or received from the shaft. it is used to convert circular motion into reciprocating motion, or vice versa. the arm may be a bent portion of the shaft, or a separate arm or disk attached to it. attached to the end of the crank by a pivot is a rod, usually called a connecting rod conrod .
grindstone machines usually have pedals for speeding up and slowing down the stone to control the sharpening process. the earliest known representation of a rotary grindstone, operated by a crank handle, is found in the carolingian manuscript known as the utrecht psalter.
the stereotypical organ grinder was a man, bearing a medium-sized barrel organ held in front of him and supported by a hinged or removable wooden stick or leg that was strapped to the back of the organ. the strap around his neck would balance the organ, leaving one hand free to turn the crank and the other to steady the organ.
an eggbeater is a handheld device with a crank on the side geared to one or more beaters. the user grips the handle with one hand and operates the crank with the other, creating the rotary action. a mixer is a kitchen utensil which uses a gear-driven mechanism to rotate a set of beaters in a bowl containing the food to be prepared. it automates .
the curta is a small mechanical calculator developed by curt herzstark. the curta's design is a descendant of gottfried leibniz's stepped reckoner and charles thomas's arithmometer, accumulating values on cogs, which are added or complemented by a stepped drum mechanism. it has an extremely compact design: a small cylinder that fits in the palm of the hand. curtas were considered the best portable calculators available until they were displaced by electronic calculators in the 1970s.
although replacing the rings or bearing shells was at one time considered typical garage work, the need for a boring or crank grinding machine exceeded this. a short block represented the set of major parts needed, those beyond the garage capabilities, in one item.
pulling the crank upwards slightly before turning performs a subtraction instead of an addition. multiplication, division, and other functions require a series of crank and carriage-shifting operations. the curta was affectionately known as the 'pepper grinder' or 'peppermill' due to its shape and means of operation.
the carpenter's brace is a compound crank. the crank set that drives a handcycle through its handles. hand winches; foot-powered cranks. the crankset that drives a bicycle via the pedals. treadle sewing machine; engines