Method of and arrangement for controlling the speed of the movements of hydraulic booms

Claim 2

In a method of controlling the speed of the movements of a working implement, said working implement being movable three-dimensionally in space by hydraulic motors and carried by a hydraulic boom, said hydraulic boom being pivotally arranged with respect to a support, and a hydraulic circuit being provided for said hydraulic motors for providing a return flow from said hydraulic motors to low pressure, the improvement comprising: selectively ramifying the return flow manually into one of at least two return flow branches, and providing flow restriction in at least said one of said branches for decreasing the speed of movement of the working implement in a step of a predetermined amount which is a function of the size of the restriction so as to obtain an accurate inching.

Claim 3

A method according to claim 1, comprising joining the return flow from at least two motors before the branching thereof.

Claim 4

A method according to claim 2, in which the working implement is pivotally mounted to the hydraulic boom and comprising pivoting said implement relative to the hydraulic boom by one of said at least two motors.

Claim 5

In a method of controlling the speed of the movements of an elongated rock drilling apparatus, said elongated rock drilling apparatus being movable three-dimensionally in space by hydraulic motors and carried by a hydraulic boom, said hydraulic boom being pivotally arranged with respect to a support, said hydraulic motors each comprising a double-acting piston movable to and fro within a cylinder chamber under the influence of hydraulic fluid respectively supplied to and returned from the opposite ends of said cylinder chamber, and the return flow from said cylinder ends being conducted to a tank, the improvement comprising: alternatively ramifying the return flow manually into one of at least two branches, and providing flow restriction in at least said one branch for decreasing the speed of said elongated rock drilling apparatus in a step of predetermined amount which is a function of the size of the restriction so as to obtain an accurate inching.

Claim 6

In a method of controlling the speed of the movements of an elongated rock drilling apparatus, said elongated rock drilling apparatus being movable three-dimensionally in space by hydraulic motors and carried by a hydraulic boom, said hydraulic boom being pivotally arranged with respect to a support, said hydraulic motors each comprising a double-acting piston movable to and fro within a cylinder chamber under the influence of hydraulic fluid respectively supplied to and returned from the opposite ends of said cylinder chamber, and the return flow from said cylinder ends being conducted to a tank, the improvement comprising: alternatively ramifying the return flow manually into one of at least two branches, and providing flow restriction in at least said one branch for decreasing the speed of said elongated rock drilling apparatus in a step of predetermined amount which is a function of the size of the restriction so as to obtain an accurate inching.

Claim 7

In a method of controlling the speed of the movements of a feed bar carrying a rock drilling machine mechanically fed therealong, of the type wherein the feed bar is movably supported on the outer end of a drill boom, the drill boom is movably carried on a drill rig, and the movements of the feed bar and the drill boom respectively are performed by double-acting pistons, each piston being movable to and fro within a cylinder chamber under the influence of hydraulic fluid respectively supplied to and returned from the opposite ends of said cylinder chamber, and the return flow from said cylinder being conducted to a tank, the improvement comprising: selectively ramifying the return flow manually into one of at least two return flow branches, providing flow restriction in said one of said branches for decreasing the speed of the feed bar in a step of predetermined amount so as to obtain an accurate inching, and joining the return flow from at least two cylinders before the branching of the return flow.

Claim 8

In a method of controlling the speed of the movements of a feed bar carrying a rock drilling machine mechanically fed therealong, of the type wherein the feed bar is movably supported on the outer end of a drill boom, the drill boom is movably carried on a drill rig, and the movements of the feed bar and the drill boom respectively are performed by double-acting pistons, each piston being movable to and fro within a cylinder chamber under the influence of hydraulic fluid respectively supplied to and returned from the opposite ends of said cylinder chamber, and the return flow from said cylinder being conducted to a tank, the improvement comprising: selectively ramifying the return flow manually into one of at least two return flow branches, providing flow restriction in said one of said branches for decreasing the speed of the feed bar in a step of predetermined amount so as to obtain an accurate inching, and joining the return flow from at least two cylinders before the branching of the return flow.

Claim 9

In a hydraulic boom arrangement comprising a boom pivotally arranged with respect to a support, means on said boom for carrying a working implement for three-dimensional movement of said working implement in space, at least one hydraulic motor connected to said boom for swinging the boom relative to the support, a pressure fluid source, means for supplying pressure fluid to said motors, a tank, and means for conducting the return fluid flow from said at least one motor to the tank via a conduit, the improvement comprising: a valve connected in said conduit, at least two branches of said conduit between said valve and said tank, fluid restriction means connected in at least one of said at least two branches, and manually operated means coupled to said valve to set said valve for selectively conducting the return fluid flow from said at least one motor through said restriction means for decreasing the speed of the working implement in a predetermined amount which is a function of the size of the restriction so as to obtain an accurate inching.

Claim 10

In a hydraulic boom arrangement comprising a boom pivotally arranged with respect to a support, means on said boom for carrying a working implement for three-dimensional movement of said working implement in space, at least one hydraulic motor connected to said boom for swinging the boom relative to the support, a pressure fluid source, means for supplying pressure fluid to said motors, a tank, and means for conducting the return fluid flow from said at least one motor to the tank via a conduit, the improvement comprising: a valve connected in said conduit, at least two branches of said conduit between said valve and said tank, fluid restriction means connected in at least one of said at least two branches, and manually operated means coupled to said valve to set said valve for selectively conducting the return fluid flow from said at least one motor through said restriction means for decreasing the speed of the working implement in a predetermined amount which is a function of the size of the restriction so as to obtain an accurate inching.

Claim 11

In a hydraulic boom arrangement comprising a boom (10) pivotally mounted on a support, means on said boom for carrying a working implement, at least one hydraulic cylinder (12) pivotally attached to said boom and to said support respectively for swinging the boom relative to the support, a pressure fluid source (21), a feed conduit coupling said fluid source to each of said at least one hydraulic cylinder, a valve means (22) in each feed conduit, a control circuit operatively coupled to said valve means, operating means (31) coupled to said control circuit for setting said valve means via said control circuit for conducting pressure fluid to said at least one cylinder from said source via said feed conduit, a tank (30), and a return conduit for conducting the return fluid flow from said at least one cylinder to said tank (30), the improvement comprising: a second valve means (27) connected in said return conduit and being operatively coupled to said control circuit, at least two branches of said return conduit between said second valve means (27) and said tank (30), and a first fluid restriction means (28) connected in at least one of said branches, said operating means (31) including means for selectively setting said second valve means via said control circuit for selectively conducting said return fluid flow through either one of said at least two branches.

Claim 12

In a hydraulic boom arrangement comprising a boom (10) pivotally mounted on a support, means on said boom for carrying a working implement, at least one hydraulic cylinder (12) pivotally attached to said boom and to said support respectively for swinging the boom relative to the support, a pressure fluid source (21), a feed conduit coupling said fluid source to each of said at least one hydraulic cylinder, a valve means (22) in each feed conduit, a control circuit operatively coupled to said valve means, operating means (31) coupled to said control circuit for setting said valve means via said control circuit for conducting pressure fluid to said at least one cylinder from said source via said feed conduit, a tank (30), and a return conduit for conducting the return fluid flow from said at least one cylinder to said tank (30), the improvement comprising: a second valve means (27) connected in said return conduit and being operatively coupled to said control circuit, at least two branches of said return conduit between said second valve means (27) and said tank (30), and a first fluid restriction means (28) connected in at least one of said branches, said operating means (31) including means for selectively setting said second valve means via said control circuit for selectively conducting said return fluid flow through either one of said at least two branches.

Claim 13

A boom arrangement according to claim 7, wherein said working implement is pivotally connected to the boom (10), and further comprising: at least a further hydraulic cylinder means (16) connected to said boom and to said working implement, a further feed conduit coupling said fluid source to said further cylinder means (16), a third valve means (26) in said further feed conduit and being operatively coupled to said control circuit, second operating means (32) for selectively setting said third valve means (26) via said control circuit for conducting pressure fluid to said further cylinder means (16), and a return conduit for conducting the return flow from said further cylinder means (16) to said tank (30), said return conduit of said further cylinder means being connected to said second valve for selectively conducting the return fluid flow through at least either one of said at least two branches.

Claim 14

A boom arrangement according to claim 8, wherein said working implement is a rock drilling apparatus.

Claim 15

A boom arrangment according to claim 7, wherein said operating means (31) is adjustable stepwise to at least a first (I) and a second (II) position respectively and sets said valve (22) when in said first position.

Claim 16

A boom arrangement according to claim 10, wherein said first fluid restriction means (28) includes a first restriction valve (28) and said operating means (31) in said first position (I) sets said second valve (27) for conducting the return fluid flow through said first restrictor valve (28).

Claim 17

A boom arrangement according to claim 10, comprising a second restrictor valve (29) in the other of said branches, and wherein said operating means (31) in said second position maintains the setting of said valve (22) and sets said second valve (27) for conducting the return flow through said second restrictor valve (29), said second restrictor valve (29) having a larger area than said first restrictor valve (28).

Claim 18

A boom arrangement according to claim 11, comprising a by-pass line from said second valve (27) to said tank, and wherein said operating means (31) in said second position maintains the setting of said valve (22) and sets said second valve (27) via said control circuit for conducting the return fluid flow via said by-pass line to tank.

Claim 19

A boom arrangement according to claim 7 comprising a second fluid restriction means (29) connected in the other of said at least two branches, the first fluid restriction means providing a greater restriction to fluid flow than said second fluid restriction means.

Claim 20

A boom arrangement according to claim 7 further comprising a by-pass line coupled from said second valve (27) to said tank for selectively by-passing the return fluid flow to said tank without passing through either of said at least two branches.