Adjustable height support

Claim 2

An adjustable height support comprising a supporting base unit including a central upstanding shaft, a second unit connected telescopically to the base unit and adapted to be raised and lowered relative to the base unit by axial movement, a gravity-responsive wedge locking means on the second unit movable therewith and also movable relative thereto, and said wedge locking means including a drag element adapted to grip said shaft and initiate the locking action of the wedge locking means when the second unit is abruptly released to a free falling condition following height adjustment of the support, lifting of the second unit serving automatically to release the wedge locking means and drag element.

Claim 3

The structure of claim 1, and the wedge locking means comprising on the second unit a freely axially movable wedge device surrounding said shaft, a cooperating tapered wedge bore on the second unit lockingly engaged by the wedge device when the wedge device moves axially in one direction on the second unit and forcing the wedge device into positive locking engagement with said shaft, said drag element comprising a canted drag ring mounted loosely on said shaft and contacting the lower end of said wedge device, and supporting and adjusting means for said canted drag ring on said second unit and allowing the inclination of the drag ring to be varied and positively limiting downward displacement of the drag ring on the second unit responsive to lifting the second unit.

Claim 4

The structure of claim 2, and said supporting and adjusting means comprising a pair of diametrically opposed adjusting screws on the lower end of the second unit having heads supporting opposite sides of the drag ring at different elevations, and a compression spring on one adjusting screw having opposite ends engaging the top of the drag ring and the bottom face of the second unit.

Claim 5

The structure of claim 2, and said freely axially movable wedge device comprising an annular array of wedge locking balls in said tapered wedge bore surrounding said shaft, and a ball retainer and actuator sleeve arranged below said balls and tapered bore and surrounding said shaft and supporting said balls and having its lower end contacting the top of the canted drag ring.

Claim 6

The structure of claim 4, and said sleeve having a diagonally inclined lower end face and the lowermost part of said end face resting on the lower side of the canted drag ring.

Claim 7

The structure of claim 5, and said second unit having a lower end cylindrical bore below the tapered wedge bore receiving said sleeve for guided axial movement therein.

Claim 8

The structure of claim 5, and a key means on the second unit engaging said sleeve and resisting rotation thereof relative to the second unit while allowing free relative axial movement of the sleeve.

Claim 9

The structure of claim 1, and the second unit including a vertical tube body telescoped over said upstanding shaft of the base unit, and at least one bearing element on the upstanding shaft slidably supporting the bore of the tube body of the second unit.

Claim 10

The structure of claim 8, and said bearing element comprising a bearing head secured to the upper end of said shaft.

Claim 11

The structure of claim 8, and said wedge locking means bodily carried by the lower end of said tube body in surrounding relationship to said upstanding shaft.

Claim 12

The structure of claim 10, and said wedge locking means on the lower end of the tube body comprising a sleeve member having an internal upwardly tapering steep conical bore, said bore surrounding said shaft concentrically, a freely axially movable sleeve surrounding said shaft below said conical bore, an array of wedge locking balls surrounding said shaft and resting on the top of said sleeve and disposed within said conical bore, and an adjustable friction drag element dependingly secured to the bottom of said sleeve member and adapted to engage said shaft grippingly for forming a support for said freely movable sleeve.