Abstract: The crane includes a swing brake device installed between a hydraulic motor and a control valve and having a flow restrictor; a first backpressure detector detecting a motor backpressure between the flow restrictor and one of ports of the hydraulic motor; a second backpressure detector detecting a motor backpressure between the flow restrictor and the other port of the hydraulic motor; and a control device. The control device has an external-force direction estimation unit that estimates a swing direction of an upperstructure under an external force acting on the upperstructure on the basis of a motor backpressure detected by the first backpuressure detector and a motor backpressure detected by the second backpressure during an operating state of the swing brake device. The control device has a notification control unit that causes the notification device to provide notification of the estimated swing direction of the upperstructure.

Abstract: A crane includes: a boom; a jib; a front post that is swingably attached to a tip end side of the boom; a rear post that is swingably attached to the tip end side of the boom; a post-side pendant member, with one end of the post-side pendant member being attached to a tip end of the rear post; a boom-side pendant member, with one end of the boom-side pendant member being attached to another end of the post-side pendant member, and another end of the boom-side pendant member being attached to the boom; and a post driving device having a link mechanism that rotates the rear post in a range including a position at which the rear post is swung down to the front post side and a position at which the rear post is swung down to the boom side, while the boom is held down in a horizontal position.

Abstract: A cylinder retraction system causes a crawler side frame hoisting hydraulic cylinder, swingably suspended on a ventral surface side of a lower boom, to swing between a retracted attitude, in which the hydraulic cylinder is set along a ventral surface of the lower boom, and an operating attitude, in which the hydraulic cylinder is oriented along a vertical direction. As the rod of the hydraulic cylinder, currently having the operating attitude, is contracted by a predetermined extent, the rod front end of the hydraulic cylinder is guided by the guiding portion until the hydraulic cylinder takes on the retracted attitude. As the hydraulic cylinder, currently having the retracted attitude, is extended by a predetermined extent, engagement between the rod front end of the hydraulic cylinder and the guiding portion is released so as to allow the hydraulic cylinder to take on the operating attitude.

Abstract: A winch braking device includes: a brake; a brake pedal; a reaction force-imparting element that imparts a reaction force to the brake pedal; a rotation link that rotates by interlocking with the foot operation at the brake pedal; a brake valve linked to the rotation link, that applies a secondary pressure to the brake in response to the foot operation at the brake pedal; and a tension spring, with one end thereof attached to the vehicle body at a predetermined position and another end thereof attached to the rotation link, that applies a force to the brake pedal along a direction opposite a direction of the foot operation. As the foot operation is performed at the brake pedal, the tension spring extends and a shortest distance between a rotational center of the rotation link and a central axis of the tension spring becomes smaller.

Abstract: A control device for a hydraulic winch includes: a hydraulic source; a variable-displacement hydraulic motor; a winch operation member; an accelerator operation quantity detection unit; an engine control unit; a rotation speed detection unit; a line pull detection unit; a condition decision unit; and a motor displacement control unit, wherein: once the condition decision unit decides that the fuel-efficient, high-speed operation condition has been established, the engine control unit sets an upper limit to the engine rotation speed at a predetermined rotation speed, lower than the maximum rotation speed.

Abstract: A counterweight suspension device includes a pair of suspension cylinders that suspends a counterweight and that are hung from first and second hanging points provided separately in a left and right direction at a top end of a rear mast. A coupling member couples cylinder rod ends of the pair with each other. A lifting member lifts the counterweight. First and second connection points of the counterweight are connected with each of the cylinder rod ends, with the first and the second connection points provided separately in the left and right direction on the counterweight for attaching the lifting member to the counterweight. A first communication circuit is provided through which rod chambers of the suspension cylinders communicate with each other. A second communication circuit is provided through which bottom chambers of the suspension cylinders communicate with each other.

Abstract: A cylinder retraction system causes a crawler side frame hoisting hydraulic cylinder, swingably suspended on a ventral surface side of a lower boom, to swing between a retracted attitude, in which the hydraulic cylinder is set along a ventral surface of the lower boom, and an operating attitude in which the hydraulic cylinder is oriented along a vertical direction. As the rod of the hydraulic cylinder, currently having the operating attitude, is contracted by a predetermined extent, the rod front end of the hydraulic cylinder is guided by the guiding portion until the hydraulic cylinder takes on the retracted attitude. As the hydraulic cylinder, currently having the retracted attitude, is extended by a predetermined extent, engagement between the rod front end of the hydraulic cylinder and the guiding portion is released so as to allow the hydraulic cylinder to take on the operating attitude.

Abstract: A construction machinery body includes: a main frame; a gantry that is derrickably linked to the main frame, and includes a front leg member and a rear leg member that is linked to the front leg member at a front end side; a connecting member that is disposed between one end portion and another end portion of the front leg member in the gantry, and includes a connecting portion and a rope attaching portion; and a coupling member that links the connecting portion of the front leg member to the main frame in a state where the gantry is retracted.

Abstract: A lower spreader of a construction machinery has a width smaller than a width of the front leg member; and a plurality of lower sheaves at the lower spreader includes at least; a first lower sheave at which the derricking rope let out from the derricking drum is first wound; a second lower sheave, disposed on a side where a fixed end of the derricking rope at which the derricking rope is fastened is located, at which the derricking rope is wound last; and a third lower sheave, disposed between the first lower sheave and the second lower sheave or at a position adjacent to either the first lower sheave or the second lower sheave, at which the derricking rope, running from an upper sheave among the plurality of upper sheaves at the upper spreader is wound so as to run toward another upper sheave at the upper spreader.

Abstract: A winch braking device includes: a brake; a brake pedal; a reaction force-imparting element that imparts a reaction force to the brake pedal; a rotation link that rotates by interlocking with the foot operation at the brake pedal; a brake valve linked to the rotation link, that applies a secondary pressure to the brake in response to the foot operation at the brake pedal; and a tension spring, with one end thereof attached to the vehicle body at a predetermined position and another end thereof attached to the rotation link, that applies a force to the brake pedal along a direction opposite a direction of the foot operation. As the foot operation is performed at the brake pedal, the tension spring extends and a shortest distance between a rotational center of the rotation link and a central axis of the tension spring becomes smaller.

Abstract: A control device for a hydraulic winch includes: a hydraulic source; a variable-displacement hydraulic motor; a winch operation member; an accelerator operation quantity detection unit; an engine control unit; a rotation speed detection unit; a line pull detection unit; a condition decision unit; and a motor displacement control unit, wherein: once the condition decision unit decides that the fuel-efficient, high-speed operation condition has been established, the engine control unit sets an upper limit to the engine rotation speed at a predetermined rotation speed, lower than the maximum rotation speed.

Abstract: A counterweight suspension device includes: a pair of suspension cylinders that suspends a counterweight, and that are hung from a first and a second hanging points provided separately in a left and right direction at a top end of a rear mast; a coupling member that couples cylinder rod ends of the pair of suspension cylinders with each other; a lifting member for lifting the counterweight, that connects a first and a second connection points of the counterweight with each of the cylinder rod ends of the pair of suspension cylinders, with the first and the second connection points provided separately in the left and right direction on the counterweight for attaching the lifting member to the counterweight; a first communication circuit through which rod chambers of the pair of suspension cylinders communicate with each other; and a second communication circuit through which bottom chambers of the pair of suspension cylinders communicate with each other.

Abstract: A rotating superstructure includes: a front block on which a power unit that includes a prime mover; and a rear block on which a unit for raising and lowering a boom that includes a winch, a, and an arm. And the rotating superstructure is configured to be split into the front block and the rear block.

Abstract: A counterweight installation device includes: a weight support unit provided on a rear end of a body frame of a construction machine; a weight mounting unit disposed on a counterweight; a pin member for mounting the counterweight adapted to move between a first position at which the weight mounting unit is mounted on the weight support unit and a second position at which the weight mounting unit is dismounted from the weight support unit; and a rod device, one end of which is linked with the pin member and an other end of which extends so as to project to an outside of the counterweight, adapted to move the pin member between the first position and the second position by operation at the other end thereof.

Abstract: A counterweight installation device includes: a weight support unit provided on a rear end of a body frame of a construction machine; a weight mounting unit disposed on a counterweight; a pin member for mounting the counterweight adapted to move between a first position at which the weight mounting unit is mounted on the weight support unit and a second position at which the weight mounting unit is dismounted from the weight support unit; and a rod device, one end of which is linked with the pin member and an other end of which extends so as to project to an outside of the counterweight, adapted to move the pin member between the first position and the second position by operation at the other end thereof.

Abstract: A counterweight device comprises a first engaging groove formed at a counterweight, a second engaging groove formed at a body frame, a first engaging member projecting at the counterweight, which engages at the second engaging groove when mounting the counterweight, a second engaging member projecting at the body frame, which engages at the first engaging groove when mounting the counterweight. A locking device that locks the counterweight to the body frame when the first engaging member is engaged at the second engaging groove and the second engaging member is engaged at the first engaging groove.

Abstract: The present invention includes a hydraulic source (23), a pressure reducing valve (22) that reduces hydraulic pressure from the hydraulic source (23) so as secondary pressure P to become large in accordance with increase in an extent to which a pusher (25) is pressed in, a negative brake mechanism (10) that releases braking by secondary pressure P from the pressure-reducing valve (22) and causes braking to operate in response to cutting of secondary pressure (P), a brake pedal (24) provided so as to pull out the pusher (25) according to a depression operation, and a spring member (27) that pushes in the pusher (25) so as to release braking performed by the negative brake mechanism (10) when the brake pedal (24) is not operated.

Abstract: A counterweight device comprises a first engaging groove formed at a counterweight, a second engaging groove formed at a body frame, a first engaging member projecting at the counterweight, which engages at the second engaging groove when mounting the counterweight, a second engaging member projecting at the body frame, which engages at the first engaging groove when mounting the counterweight. A locking device that locks the counterweight to the body frame when the first engaging member is engaged at the second engaging groove and the second engaging member is engaged at the first engaging groove.