Tractor Jacks: Small but Mighty Mechanical Lifting Devices
When it came to lifting tractors and equipment, early mechanical lifting devices eased heavy loads.
Above: An Oliver wood jack. Note the wood frame (which acts as the fulcrum), the notched lifting arm, the small wheel at the front (used for positioning) and the lever at the rear used to raise the implement.
Top: This No. 4 Galion jack shows the double-clevis raising mechanism. The upper clevis does the lifting and the lower clevis holds the load.Center: Silver King 5-ton bottle hydraulic jack made in Cleveland, Ohio.Bottom: This wood jack has a metal strip affixed to the lifting notches to provide for longer life.Left: Barrett 10-ton jack with removable top plate.
Left: In the Avery jack’s lifting/locking mechanism, the pawl does the lifting while the hinged clevis locks and holds the load.
Right: A Barth No. 5 6-ton jack. This jack uses half-inch increments. The jack levers both up and down, and a twist knob on the front switches direction.
Above: No. 4 heavy-duty jacks. Each uses longer wood handles and double-clevis lifting hinges and catch hinges. A Huber jack (left); Galion Iron Works jack (right).
Left: A trio of No. 3 “rat tail”-style lifting jacks. The different lifting and latching mechanisms are visible in this photograph. Left to right: a double-clevis Huber, single-clevis with a thumb-operated release catch (at top) and an Elward with double-foot and wire-release catch (also at top).