Automatic bucket positioning device

Claim 2

An assembly comprising: a. a double acting hydraulic power unit comprising a cylinder and a piston mounted therein for longitudinal movement of the cylinder and piston with respect to one another, b. a neutralizable control valve connecting the ends of the cylinder with a source of hydraulic pressure fluid and drain so as to move the piston in one direction and the other with respect to the cylinder and neutralizable to block both ends of the cylinder by hydraulic lock action to fix the piston and cylinder against relative movement, c. means for holding the control valve out of the hydrauliclock, hold setting and maintained in a setting involving connection of one end of the cylinder with the source and the other end with drain, and d. further means for causing release of the holding means, and neutralization of the control valve back to hold setting, in response to relative pressures at the said one end and a mid region of the cylinder over which the piston will pass, and including a member responsive to pressure equalization and having hydraulic connection to the fluid inside respectively said mid region and one end of the cylinder.

Claim 3

The assembly as specified in claim 1, the further means being a pilot valve having other connections to the source and drain independent of the control valve, the further means operating in response to connection through the pilot valve with drain to enable actuation of the holding means to occur, the further means operating in response to connection through the pilot valve with the source to release the holding means, the further means being connected by the pilot valve to drain in response to movement of the piston from the said one end of the cylinder toward the said mid region thereon, and being connected to the source in response to movement of the piston from the said one end of the cylinder beyond the said mid region thereof.

Claim 4

An assembly comprising: a. a power unit comprising a cylinder and a piston mounted therein for longitudinal movement of the cylinder and piston with respect to one another, b. a source of hydraulic fluid under pressure, c. a control valve connected with the source and the ends of the cylinder so as in a first setting to block the flow of hydraulic fluid to and from the cylinder and connect the source with drain, in a second setting to connect one end of the cylinder with the source and the other end with drain, and in a third setting to connect the said one end of the cylinder with drain and the said other end with the source, d. spring means for urging the control valve to its first setting, e. manual means for acting against the spring means to bring the control valve to its second and third settings, f. means for holding the control valve in its second setting, g. a pilot valve for causing release of the holding means, and h. first and second lines connecting the pilot valve with said one end of the cylinder and a mid region of the cylinder, respectively, for enabling the holding means to be activated during the second setting of the valve, the first line thereby communicating the pressure of said source to the pilot valve when said one end of the cylinder is connected as aforesaid to said source, the second line thereby communicating drain pressure to the pilot valve when the piston is between the said one end and the said mid region of the cylinder and the said other end of the cylinder is connected as aforesaid with drain, the piston being moved with respect to the cylinder toward its said other end by virtue of the connection of its said other end to drain and its said one end with the source, the passage of the piston beyond the mid region of the cylinder at which the said second line is connected shifting the connection of the same from drain to the source and thereby making the pilot valve release the holding means, whereby the Spring means returns the valve to its first setting and further movement of the piston with respect to the cylinder is prevented by blocking of flow of hydraulic fluid to and from the cylinder, an additional spring means for actuating the holding means, third and fourth lines connecting the pilot valve with the source and drain, respectively, independently of the first and second lines, the valve, and the cylinder, and a fifth line connecting the pilot valve with the holding means, the connection of the pilot valve with the source through the first line and with drain through the second line regulating the pilot valve so as to connect the holding means with drain via the fifth line, the pilot valve, and the fourth line and thereby enable the additional spring means to actuate the holding means, switching of the second line to the source from drain due to movement of the piston beyond the mid region of the cylinder connected to the second line, regulating the pilot valve so as to connect the holding means with the source via the fifth line, the pilot valve, and the third line and thereby enable the source to act against the additional springs means to release the holding means.

Claim 5

An assembly comprising: a. a power unit comprising a cylinder and a piston mounted therein for longitudinal movement of the cylinder and piston with respect to one another, b. a source of hydraulic fluid under pressure, c. a control valve connected with the source and the ends of the cylinder so as in a first setting to block the flow of hydraulic fluid to and from the cylinder and connect the source with drain, in a second setting to connect one end of the cylinder with the source and the other end with drain, and in a third setting to connect the said one end of the cylinder with drain and the said other end with the source, d. spring means for urging the control valve to its first setting, e. manual means for acting against the spring means to bring the control valve to its second and third settings, f. means for holding the control valve in its second setting, g. a pilot valve for causing release of the holding means, and h. first and second lines connecting the pilot valve with said one end of the cylinder and a mid region of the cylinder, respectively, for enabling the holding means to be activated during the second setting of the valve, the first line thereby communicating the pressure of said source to the pilot valve when said one end of the cylinder is connected as aforesaid to said source, the second line thereby communicating drain pressure to the pilot valve when the piston is between the said one end and the said mid region of the cylinder and the said other end of the cylinder is connected as aforesaid with drain, the piston being moved with respect to the cylinder toward its said other end by virtue of the connection of its said other end to drain and its said one end with the source, the passage of the piston beyond the mid region of the cylinder at which the said second line is connected shifting the connection of the same from drain to the source and thereby making the pilot valve release the holding means, whereby the Spring means returns the valve to its first setting and further movement of the piston with respect to the cylinder is prevented by blocking of flow of hydraulic fluid to and from the cylinder, an additional spring means for actuating the holding means, third and fourth lines connecting the pilot valve with the source and drain, respectively, independently of the first and second lines, the valve, and the cylinder, and a fifth line connecting the pilot valve with the holding means, the connection of the pilot valve with the source through the first line and with drain through the second line regulating the pilot valve so as to connect the holding means with drain via the fifth line, the pilot valve, and the fourth line and thereby enable the additional spring means to actuate the holding means, switching of the second line to the source from drain due to movement of the piston beyond the mid region of the cylinder connected to the second line, regulating the pilot valve so as to connect the holding means with the source via the fifth line, the pilot valve, and the third line and thereby enable the source to act against the additional springs means to release the holding means.