Crane with a pivoted boom and a float valve therefor

Claim 2

In a crane having carrier means, boom means, hydraulic cylinder means for controlling elevation of the boom means, and load-holding check valve means for the hydraulic cylinder means to prevent accidental loss of actuating pressure, intentionally operable means for allowing the boom means to float during transportation of the crane between job sites comprising: float valve means between the check valve means and the hydraulic cylinder means having actuating fluid channels extending between the check valve means and the hydraulic cylinder means, a cross-over channel means extending between the actuating fluid channels, and flow control means having a first condition operable to prevent fluid communication between the actuating fluid channels and a second condition operable to permit fluid communication between the actuating fluid channels; and means for causing the flow control means to assume the first condition during normal load lifting operations of said crane and being intentionally operable for causing the flow control means to assume the second condition to facilitate crane transporting operations.

Claim 3

The crane of claim 1 wherein: the flow control means includes a valve spool slidably disposed in the cross-over channel means having a valve protrusion thereon which selectively cooperates with the cross-over channel means to permit and prohibit fluid communication through the cross-over channel means.

Claim 4

The crane of claim 2 wherein: a compensatory fluid channel communicates with the cross-over channel means to supply and receive fluid as required by different cross-sectional areas of the actuating chambers of the hydraulic cylinder means; the first valve protrusion selectively cooperates with the cross-over channel means between one actuating fluid channel and the compensatory fluid channel; and the valve spool has a second valve protrusion which selectively cooperates with the cross-over channel means between another actuating fluid channel and the compensatory fluid channel.

Claim 5

The crane of claim 2 wherein the means for causing includes; biasing means acting on the valve spool operable to bias the valve spool and the valve protrusion to fluid communication prohibiting relationship with the cross-over channel means; and actuator means operable to move the valve spool to the second condition in the valve means, selectively override the biasing means to thereby establish fluid communication between the actuating fluid channels.

Claim 6

The crane of claim 4 wherein: the cross-over channel means includes an extended portion that extends beyond one actuator channel and includes a counterbore at the one end of the cross-over channel; the actuator means includes a piston carried by an end of the valve spool, disposed in the counterbore, cooperating with the counterbore to define a piston actuating chamber; and a fluid pressure port communicates with the piston actuating chamber through the valve body and is operable to receive pressurized fluid which actuates the piston.

Claim 7

In a crane having carrier means, boom means, hydraulic cylinder means for elevationally positioning the boom means, and load-holding check valve means, an improved valve means for allowing relative movement between the boom means and the carrier means during transportation comprising: first fluid passage means between the load-holding valve means and one actuating chamber of the hydraulic means operable to convey pressurized fluid during raising of the boom means; second fluid passage means between the load-holding valve means and a second actuating chamber of the hydraulic means operable to convey pressurized fluid during lowering of the boom means; cross-over passage means for establishing fluid communication between the first and second fluid passage means; flow control means movable between a flow inhibiting position in which flow through said cross-over passage means is blocked and a flow permitting position in which flow between said first and second fluid passage means through said cross-over passage means is permitted; means for biasing said flow control means to said flow inhibiting position; and actuator means for moving said flow control means to said flow permitting position.

Claim 8

In a crane having carrier means, boom means, hydraulic cylinder means for elevationally positioning the boom means, and load-holding check valve means, an improved valve means for allowing relative movement between the boom means and the carrier means during transportation comprising: first fluid passage means between the load-holding valve means and one actuating chamber of the hydraulic means operable to convey pressurized fluid during raising of the boom means; second fluid passage means between the load-holding valve means and a second actuating chamber of the hydraulic means operable to convey pressurized fluid during lowering of the boom means; cross-over passage means for establishing fluid communication between the first and second fluid passage means; flow control means movable between a flow inhibiting position in which flow through said cross-over passage means is blocked and a flow permitting position in which flow between said first and second fluid passage means through said cross-over passage means is permitted; means for biasing said flow control means to said flow inhibiting position; and actuator means for moving said flow control means to said flow permitting position.

Claim 9

The crane of claim 6 having: valve body means mounted between the load-holding valve means and the hydraulic cylinder means; the first fluid passage means and the second fluid passage means being a first channel and a second channel, respectively, extending through the valve body means; the cross-over passage means being a cross-over channel connecting the first and second channel in the valve body means; and fluid compensating means including a supply channel communicating with the cross-over channel between the first channel and the second channel being operable to furnish fluid to said cross-over channel during demand and operable to receive fluid from said cross-over channel during surplusage.

Claim 10

The crane of claim 7 wherein the flow control means includes a spool means and the biasing means comprises a resilient member which bears against one end of the spool means and against a closed end of the cross-over channel to generate a longitudinal force holding the spool means in the flow inhibiting position.

Claim 11

The crane of claim 7 wherein the actuator means includes: a pilot pressure port in the valve body means communicating with the one end of the cross-over channel; and a fluid pressure responsive piston at an end of the flow control means in the one of the cross-over channel, cooperating with the cross-over channel end to define a piston actuating chamber that is operable to receive pressurized fluid from the pilot pressure port for translating the flow control means from the flow inhibiting position to the flow permitting position.

Claim 12

In a crane having a wheeled carrier, a superstructure, boom means, hydraulic cylinder means for boom elevation control, and load-holding check valve means, means for allowing the boom means to float during crane transportation, comprising: a valve body having an end surface, a side surface, a first surface mounted on the hydraulic cylinder means, a second surface to which the load-holding check valve means is secured, first and second actuating fluid channels to provide fluid communication between the first and second surfaces, a cross-channel communicating with the first and second actuating channels and the end surface and having a counterbore at the end surface, and a compensatory fluid channel communicating with the cross-channel between the first and second actuating channels; a valve stem slidable in the cross-channel, having a first valve protrusion between the first actuating fluid channel and the compensatory fluid channel, a second valve protrusion between the second actuating fluid channel and the compensatory fluid channel, and an enlarged end portion cooperating with the counterbore to define a fluid pressure chamber; biasing means acting on the enlarged end portion to urge the valve protrusions into a flow inhibiting position; a cover plate on the end surface of the valve body to seal the counterbore and retain the biasing means; and a pressure fluid port extending between the fluid pressure chamber and the side surface of the valve body and adapted to admit pressurized fluid to the chamber to move the valve stem against the biasing means and move the valve protrusions to a flow permitting position.

Claim 13

In a crane having a wheeled carrier, a superstructure, boom means, hydraulic cylinder means for boom elevation control, and load-holding check valve means, means for allowing the boom means to float during crane transportation, comprising: a valve body having an end surface, a side surface, a first surface mounted on the hydraulic cylinder means, a second surface to which the load-holding check valve means is secured, first and second actuating fluid channels to provide fluid communication between the first and second surfaces, a cross-channel communicating with the first and second actuating channels and the end surface and having a counterbore at the end surface, and a compensatory fluid channel communicating with the cross-channel between the first and second actuating channels; a valve stem slidable in the cross-channel, having a first valve protrusion between the first actuating fluid channel and the compensatory fluid channel, a second valve protrusion between the second actuating fluid channel and the compensatory fluid channel, and an enlarged end portion cooperating with the counterbore to define a fluid pressure chamber; biasing means acting on the enlarged end portion to urge the valve protrusions into a flow inhibiting position; a cover plate on the end surface of the valve body to seal the counterbore and retain the biasing means; and a pressure fluid port extending between the fluid pressure chamber and the side surface of the valve body and adapted to admit pressurized fluid to the chamber to move the valve stem against the biasing means and move the valve protrusions to a flow permitting position.

Claim 14

In a crane having carrier means, boom means, and hydraulic cylinder means for controlling elevation of the boom means, an improved valve stack for allowing relative movement between the boom means and the carrier means during crane transportation comprising: first passage means communicating with a first actuating chamber of the hydraulic cylinder means and operable to convey pressurized fluid during raising of the boom means; second passage means communicating with the second actuating chamber of the hydraulic cylinder means and operable to convey pressurized fluid during lowering of the boom means; check valve means in the first passage means operable to prevent fluid flow from the first actuating chamber and having pilot means operable in response to fluid pressure in the second passage means to permit fluid flow from the first actuating chamber; cross-over passage means for allowing fluid communication between the first and second actuating chamber; and flow control means movable between a flow inhibiting condition in which flow through the cross-over passage means is restricted and a flow allowing condition in which flow through the cross-over passage means is allowed.

Claim 15

In a crane having carrier means, boom means, and hydraulic cylinder means for controlling elevation of the boom means, an improved valve stack for allowing relative movement between the boom means and the carrier means during crane transportation comprising: first passage means communicating with a first actuating chamber of the hydraulic cylinder means and operable to convey pressurized fluid during raising of the boom means; second passage means communicating with the second actuating chamber of the hydraulic cylinder means and operable to convey pressurized fluid during lowering of the boom means; check valve means in the first passage means operable to prevent fluid flow from the first actuating chamber and having pilot means operable in response to fluid pressure in the second passage means to permit fluid flow from the first actuating chamber; cross-over passage means for allowing fluid communication between the first and second actuating chamber; and flow control means movable between a flow inhibiting condition in which flow through the cross-over passage means is restricted and a flow allowing condition in which flow through the cross-over passage means is allowed.

Claim 16

The crane of claim 11 wherein: the cross-over passage means communicates with the first and second fluid passage means; and the flow control means includes a valve spool with a valve member slidably mounted in the cross-over passage means and operable between a flow inhibiting position where the valve member inhibits fluid flow through the cross-over passage means and a flow allowing position where the valve member allows fluid flow through the cross-over passage means, biasing means acting on the valve spool and operable to urge the valve spool to the flow inhibiting position, and actuator means acting on the valve spool in opposition to the biasing means and operable to move the valve spool to the flow allowing position.

Claim 17

In a crane having carrier means, boom means, and hydraulic cylinder means for controlling elevation of the boom means, an improved valve stack for allowing relative movement between the boom means and the carrier means during crane transportation comprising: body means operable for mounting on the hydraulic cylinder means and having a first channel communicating with a first actuating chamber of the hydraulic cylinder means and operable to convey fluid during raising and lowering of the boom means, a second channel communicating with a second actuating chamber of the hydraulic cylinder means and operable to convey fluid during raising and lowering of the boom means, a pilot passage extending between the first and second channels and communicating with the second channel, a cross-over channel communicating with the first and second channels, having a bore and a valve seat and operable to provide fluid communication between the first and second channels, and a compensatory fluid channel communicating with the cross-over channel at a location between the bore and the valve seat; check valve means in the first channel operable to prevent fluid flow from the first actuating chamber, and being enabled by fluid pressure in the pilot passage to allow fluid flow from the first actuating chamber; a valve spool having a first and a second valve protrusion spaced to correspond with the bore and the valve seat, slidably mounted in the cross-over channel between a first position in which each valve protrusion blocks fluid flow between a corresponding one of the first and second channels and the compensatory fluid channel and a second position in which flow is permitted between the first channel, the second channel and the compensatory fluid channel; biasing means acting on the valve spool to urge the valve spool toward the first position; and actuator means operable to act on the valve spool in opposition to the biasing means and slide the valve spool to the second position.

Claim 18

In a crane having carrier means, boom means, and hydraulic cylinder means for controlling elevation of the boom means, an improved valve stack for allowing relative movement between the boom means and the carrier means during crane transportation comprising: body means operable for mounting on the hydraulic cylinder means and having a first channel communicating with a first actuating chamber of the hydraulic cylinder means and operable to convey fluid during raising and lowering of the boom means, a second channel communicating with a second actuating chamber of the hydraulic cylinder means and operable to convey fluid during raising and lowering of the boom means, a pilot passage extending between the first and second channels and communicating with the second channel, a cross-over channel communicating with the first and second channels, having a bore and a valve seat and operable to provide fluid communication between the first and second channels, and a compensatory fluid channel communicating with the cross-over channel at a location between the bore and the valve seat; check valve means in the first channel operable to prevent fluid flow from the first actuating chamber, and being enabled by fluid pressure in the pilot passage to allow fluid flow from the first actuating chamber; a valve spool having a first and a second valve protrusion spaced to correspond with the bore and the valve seat, slidably mounted in the cross-over channel between a first position in which each valve protrusion blocks fluid flow between a corresponding one of the first and second channels and the compensatory fluid channel and a second position in which flow is permitted between the first channel, the second channel and the compensatory fluid channel; biasing means acting on the valve spool to urge the valve spool toward the first position; and actuator means operable to act on the valve spool in opposition to the biasing means and slide the valve spool to the second position.