Counter-balanced crane structure

Claim 2

Counter-balanced crane structure, comprising: an earth-borne crane base supporting a horizontal load platform rotatable about a first vertical axis relative to groundengaging members; an upstanding angularly disposed main boom pivotally mounted on said load platform about a horizontal boom axis and diverging upwardly from said vertical axis, said main boom being equipped with load hoisting means; an earth-borne mobile counterweight unit spaced a substantial distance laterally from said crane base in diametric opposition to said main boom with respect to said first vertical axis, said mobile counterweight unit being arranged relative to said crane base for movement in a circumferential path about the vertical axis of said load platform; said counterweight unit having a counterweight housing supported on a mobile base in which the mobile base is rotatable about a second vertical axis relative to the counterweight housing; power means independent of said crane base and operably connected to said mobile base for selectively moving the mobile counterweight unit in said circumferential path; rigid spreader link means operably connected between said load platform and said counterweight housing for maintaining said counterweight housing diametrically opposite to said boom and for applying rotational torque to said load platform about said first vertical axis in response to movement of said mobile counterweight unit along said circumferential path; a power source and winching means operably connected with said load hoisting means; an upright stay mast mounted on said load platform; and guying means between the upper portion of said main boom, the stay mast and said mobile counterweight unit whereby the weight of the latter is applied to the upper ends of said main boom and said stay mast in counterbalancing relation to loads borne by said main boom.

Claim 3

The crane structure according to claim 1 in which the power source and winching means is mounted on said mobile counterweight unit.

Claim 4

The crane structure according to claim 1 in which the crane base is mobile and self-propelled by a second power means independent of the power means connected to the counterweight mobile base.

Claim 5

The crane structure according to claim 1 in which the mobile counterweight unit is adapted to be steered and to have mobility in all directions.

Claim 6

Counter-balanced crane construction, comprising: an earth-borne crane base unit having a pivotal load platform mounted thereon to rotate about a first vertical axis relative to ground-engaging members; an upstanding main boom pivotally mounted to said load platform about a horizontal boom axis radially displaced from said first vertical axis; a self-propelled earth-borne mobile uNit spaced radially from said crane base unit in the direction from the mounting of said main boom through said first vertical axis; said self-propelled earth-borne mobile unit having a counterweight housing supported on a powered mobile base in which the powered mobile base is rotatable about a second vertical axis relative to the counterweight housing; a rigid spreader link connected between said load platform of said crane base unit and said counterweight housing and operable upon movement of said mobile unit to apply torque upon said load platform about said vertical axis while maintaining said counterweight housing diametrically opposed to said main boom with respect to said first axis; a stay mast pivotally mounted about a horizontal axis on said load platform positioned opposite said main boom with respect to said vertical axis and diverging upward relative to said main boom, the upper end of said stay mast being in overlying relation to said mobile unit; means between the upper end of said stay mast and said mobile unit whereby the weight of said mobile unit is applied in a downward direction to the upper end of said stay mast; boom suspension means between the upper end of said main boom and the upper end of said stay mast; load raising and lowering means on said main boom depending from the upper end of said main boom opposite to said boom suspension means; and powered winching means operably connected to said load raising and lowering means on said main boom and located so that the weight thereof is essentially applied downward to the upper end of said stay mast.

Claim 7

Counter-balanced crane construction, comprising: an earth-borne crane base unit having a pivotal load platform mounted thereon to rotate about a first vertical axis relative to ground-engaging members; an upstanding main boom pivotally mounted to said load platform about a horizontal boom axis radially displaced from said first vertical axis; a self-propelled earth-borne mobile uNit spaced radially from said crane base unit in the direction from the mounting of said main boom through said first vertical axis; said self-propelled earth-borne mobile unit having a counterweight housing supported on a powered mobile base in which the powered mobile base is rotatable about a second vertical axis relative to the counterweight housing; a rigid spreader link connected between said load platform of said crane base unit and said counterweight housing and operable upon movement of said mobile unit to apply torque upon said load platform about said vertical axis while maintaining said counterweight housing diametrically opposed to said main boom with respect to said first axis; a stay mast pivotally mounted about a horizontal axis on said load platform positioned opposite said main boom with respect to said vertical axis and diverging upward relative to said main boom, the upper end of said stay mast being in overlying relation to said mobile unit; means between the upper end of said stay mast and said mobile unit whereby the weight of said mobile unit is applied in a downward direction to the upper end of said stay mast; boom suspension means between the upper end of said main boom and the upper end of said stay mast; load raising and lowering means on said main boom depending from the upper end of said main boom opposite to said boom suspension means; and powered winching means operably connected to said load raising and lowering means on said main boom and located so that the weight thereof is essentially applied downward to the upper end of said stay mast.

Claim 8

The crane structure of claim 5 in which the winching means is mounted on said mobile counterweight unit.

Claim 9

The crane structure of claim 5 in which the winching means is mounted on the rigid spreader link adjacent its connection to said mobile counterweight unit.

Claim 10

Counterbalanced crane structure, comprising: an earth-borne crane base supporting a horizontal load platform rotatable about a first vertical axis relative to ground engaging members; an upstanding angularly disposed main boom mounted on said load platform and extending outwardly from said vertical axis, said main boom being equipped with load hoisting means; an earth-borne mobile counterweight unit spaced a substantial distance laterally from said crane base in diametric opposition to said main boom with respect to said first vertical axis, said unit being arranged relative to said crane base for movement in a circumferential path about the first axis; said counterweight unit having a counterweight housing supported on a mobile base in which the mobile base is rotatable about a second vertical axis relative to the counterweight housing; power means independent of said crane base and operably connected to said mobile base for selectively moving the counterweight about said circumferential path; rigid spreader link means operably connected between said load platform and said counterweight housing for maintaining said counterweight housing diametrically opposite to said boom while the counterweight unit is moved in said circumferential path and for applying rotational torque to said load platform about said vertical axis in response to movement imparted to said mobile counterweight unit along said circumferential path by said power means; a power source and winching means operably connected with said load hoisting means; and guying means between the upper portion of said main boom and said mobile counterweight unit whereby the weight of the latter is applied to the upper end of said boom in counterbalancing relation to loads borne by said main boom.

Claim 11

Counterbalanced crane structure, comprising: an earth-borne crane base supporting a horizontal load platform rotatable about a first vertical axis relative to ground engaging members; an upstanding angularly disposed main boom mounted on said load platform and extending outwardly from said vertical axis, said main boom being equipped with load hoisting means; an earth-borne mobile counterweight unit spaced a substantial distance laterally from said crane base in diametric opposition to said main boom with respect to said first vertical axis, said unit being arranged relative to said crane base for movement in a circumferential path about the first axis; said counterweight unit having a counterweight housing supported on a mobile base in which the mobile base is rotatable about a second vertical axis relative to the counterweight housing; power means independent of said crane base and operably connected to said mobile base for selectively moving the counterweight about said circumferential path; rigid spreader link means operably connected between said load platform and said counterweight housing for maintaining said counterweight housing diametrically opposite to said boom while the counterweight unit is moved in said circumferential path and for applying rotational torque to said load platform about said vertical axis in response to movement imparted to said mobile counterweight unit along said circumferential path by said power means; a power source and winching means operably connected with said load hoisting means; and guying means between the upper portion of said main boom and said mobile counterweight unit whereby the weight of the latter is applied to the upper end of said boom in counterbalancing relation to loads borne by said main boom.