Automatic bucket positioning device

Claim 2

A loader comprising: a. a tractor, b. a boom arm having one end pivotally connected with the tractor for movement of the other end between a lowered position adjacent the ground and an elevated position removed from the ground, c. a bucket connected with said other end of the arm for movement with respect to said arm between a dumping position and a break-out position and across a digging position located between the dumping and break-out positions, d. a power unit comprising a cylinder having one end connected to the boom arm, a piston slidably mounted in the cylinder, and a rod secured to the piston and projecting from the other end of the cylinder to an operative connection with the bucket for pivoting the same, e. a control valve having connections with the ends of the cylinder, a source of fluid under pressure, and drain, f. means for biasing the control valve to a first setting in which the connections to the ends of the cylinder are blocked and the source is connected with drain, g. manual means for bringing the control valve to a second setting in which the said one end of the cylinder is connected to the source and the said other end to drain and to a third setting in which the connections of the ends of the cylinder to the source and drain are reversed. h. means for holding the control valve in its second setting; i. a pilot valve for regulating the holding means, having one end connected to the said one end of the cylinder and the other end connected to an intermediate region thereof so as to be sensitive to pressure in the cylinder at said one end and said intermediate region, and j. lines connecting the pilot valve to the source and drain independently of the control valve.

Claim 3

The loader specified in claim 1 and further comprising a spring for actuating the holding means in the second setting of the control valve, such actuation being enabled to occur in the second setting by virtue of the connection of the holding means via the pilot valve with drain, said connection being produced by the sensing of source pressure at the said one end of the pilot valve through connection of the said one end of the cylinder via the control valve with the source and by the sensing of drain pressure at the said other end of the pilot valve through location of the piston between the said one end and the mid-region of the cylinder and connection of the said other end of the cylinder via the control valve with drain, the passage of the piston just beyond the said mid-region of the cylinder toward the said other end thereof occurring with arrival of the bucket in digging position and switching the sensing at the said other end of the pilot valve from drain pressure to source pressure and thereby producing a connection of the holding means via the pilot valve with the source, resulting in releasing the holding means.

Claim 4

In a tractor loader having pivoted bucket means adapted to be pivotally carried, and pivoted boom means which is pivotally carried by the tractor and which pivotally carries the pivoted bucket means: hydraulic power system comprising an extensibly and foreshortenably movable, line-pressure-actuated piston connected to one of said pivoted means; a source of line pressure and low pressure; self neutralizing control valve hydraulically disposed between the piston and source, manually movable between a 1st extreme position to hydraulically direct a first of piston movements into extreme extension or extreme foreshortening and a 2nd extreme position to hydraulically direct the opposite piston movement into extreme extension or extreme foreshortening; said valve neutralizing in an intermediate position hydraulically locking the piston partway in a movement; means hydraulically connected to the piston, sensing and signalling when it is partway in at least the first of the extreme piston movements; said hydraulically connected means comprising a port in the path of travel of the piston in an area intermediate the ends of such travel, so as to be exposed to line pressure by the piston when uncovered thereby, and an hydraulic line connected to and communicating from the port an hydraulic line pressure signal when sensed by the port; a detenter to detent the valve in the extreme valve position directing the piston in at least the first movement; and signal responsive means connected to the hydraulic line so as to be responsive to the line pressure signal of the piston moving partway as aforesaid, to kickout the detenter whereby the valve neutralizes, interrupting at least the first movement of the piston and forthwith locking same.

Claim 5

In a tractor loader having pivoted bucket means adapted to be pivotally carried, and pivoted boom means which is pivotally carried by the tractor and which pivotally carries the pivoted bucket means: hydraulic power system comprising an extensibly and foreshortenably movable, line-pressure-actuated piston connected to one of said pivoted means; a source of line pressure and low pressure; self neutralizing control valve hydraulically disposed between the piston and source, manually movable between a 1st extreme position to hydraulically direct a first of piston movements into extreme extension or extreme foreshortening and a 2nd extreme position to hydraulically direct the opposite piston movement into extreme extension or extreme foreshortening; said valve neutralizing in an intermediate position hydraulically locking the piston partway in a movement; means hydraulically connected to the piston, sensing and signalling when it is partway in at least the first of the extreme piston movements; said hydraulically connected means comprising a port in the path of travel of the piston in an area intermediate the ends of such travel, so as to be exposed to line pressure by the piston when uncovered thereby, and an hydraulic line connected to and communicating from the port an hydraulic line pressure signal when sensed by the port; a detenter to detent the valve in the extreme valve position directing the piston in at least the first movement; and signal responsive means connected to the hydraulic line so as to be responsive to the line pressure signal of the piston moving partway as aforesaid, to kickout the detenter whereby the valve neutralizes, interrupting at least the first movement of the piston and forthwith locking same.

Claim 6

The invention of claim 3, the responsive means characterized by: a depression movable by the valve into positions corresponding with positions of the latter said depression in the position corresponding to the neutralized-valve-intermediate position, confronting smooth means inactive in character; said depression, is the position corresponding to the extreme valve position directing the piston in its first movement, confronting a detent in the detenter active to protrude into the depression and detent the valve in the described way; said depression, in the position corresponding to the extreme valve position directing the piston in said opposite movement, confronting smooth means inactive in character so that valve detenting occurs in moving the piston in one direction only.

Claim 7

The invention of claim 4, the piston pivoting said pivoted bucket means full forward into the extreme dump position when the valve is manually sustained in an extreme position hydraulically directing said opposite piston movement; the piston pivoting the bucket Means full back into the extreme carry position when the valve is manually sustained in an extreme valve position hydraulically directing the first piston movement, the piston pivoting and holding the bucket means for digging when the valve is sustained and released automatically in the just said extreme valve position.