A mobile pipelayer machine includes a machine chassis having a forward end, a rear end, a first side, and a second side, and a boom extending from the first side of the machine chassis. The mobile pipelayer machine also includes a movable counterweight system extending from the second side of the machine chassis, the movable counterweight system being selectively movable to change a center of gravity of the machine in at least one of a forward or a rearward direction.

A mobile pipelayer machine includes a machine chassis having a forward end, a rear end, a first side, and a second side, and a boom extending from the first side of the machine chassis. The mobile pipelayer machine also includes a movable counterweight system extending from the second side of the machine chassis, the movable counterweight system being selectively movable to change a center of gravity of the machine in at least one of a forward or a rearward direction.

A method for determining stability of a vehicle having a load suspended from the vehicle is provided. The method can include obtaining measurements from a plurality of sensors positioned on the vehicle, obtaining a measurement from a vehicle accelerometer operative to determine an inclination of the vehicle, determining a position of the load suspended from the vehicle, determining a slung load of the load suspended from the vehicle, using the determined slung load and the determined position of the load suspended from the vehicle, determining tipping moments acting on the vehicle, determining righting moments acting on the vehicle and determining a tipping stability based on the determined tipping moments and determined righting moments.

A method for determining stability of a vehicle having a load suspended from the vehicle is provided. The method can include obtaining measurements from a plurality of sensors positioned on the vehicle, obtaining a measurement from a vehicle accelerometer operative to determine an inclination of the vehicle, determining a position of the load suspended from the vehicle, determining a slung load of the load suspended from the vehicle, using the determined slung load and the determined position of the load suspended from the vehicle, determining tipping moments acting on the vehicle, determining righting moments acting on the vehicle and determining a tipping stability based on the determined tipping moments and determined righting moments.

Provided is a crane capable of changing a moment on a counterweight side without changing a total weight of the crane by using a simple method. The crane includes a base, and a swiveling body that is provided above the base so as to swivel about a pivot center, and includes a boom and a counterweight attaching unit. The counterweight attaching unit includes a plurality of attaching positions, and is configured to selectively attach and detach the counterweight to and from any attaching position among the plurality of attaching positions, and the plurality of attaching positions is positions of which distances from the pivot center are different from each other.

Provided is a crane capable of changing a moment on a counterweight side without changing a total weight of the crane by using a simple method. The crane includes a base, and a swiveling body that is provided above the base so as to swivel about a pivot center, and includes a boom and a counterweight attaching unit. The counterweight attaching unit includes a plurality of attaching positions, and is configured to selectively attach and detach the counterweight to and from any attaching position among the plurality of attaching positions, and the plurality of attaching positions is positions of which distances from the pivot center are different from each other.

A changing device easily and safely changes the posture of the backstop of a crane between a support posture and a storage posture. The backstop posture changing device is provided with a first support member, a second support member, a push-up mechanism, and a connection member. The first support member and the second support member are rotationally connected to a backstop and a lower boom respectively. When a cylinder rod of the push-up mechanism is extended with respect to a cylinder body, a push-up member pushes up the first support member and the posture of the backstop is changed from a storage posture on the lower boom to a support posture in which it is possible to support a boom while the crane is in a working posture.

A changing device easily and safely changes the posture of the backstop of a crane between a support posture and a storage posture. The backstop posture changing device is provided with a first support member, a second support member, a push-up mechanism, and a connection member. The first support member and the second support member are rotationally connected to a backstop and a lower boom respectively. When a cylinder rod of the push-up mechanism is extended with respect to a cylinder body, a push-up member pushes up the first support member and the posture of the backstop is changed from a storage posture on the lower boom to a support posture in which it is possible to support a boom while the crane is in a working posture.

Provided is a periphery monitoring device for a work machine that displays an overhead image of the work machine and surroundings of the work machine, the device including: a detector that detects a distance to a surrounding object with respect to the work machine; and a display that displays the object in the overhead image with the distance between the work machine and the object reflected, in which a display range of the display for the object is a range obtained by extracting a portion of a detection range of the detector.

A lift machine includes a machine chassis, a boom extending from the machine chassis, and a connector extending from the boom for coupling to a load. The machine further includes a control system that determines a lift capacity of the machine based on a skew of the connector caused by the load.