Abstract: An arm-type assistance device includes a pillar, a first support portion, a first arm, a second support portion, a second arm, a third arm, an operating unit, and a cargo holding unit. The first arm includes a first member, a first air cylinder, and a second member. The first support portion, the first member, the second support portion, and the second member form a parallel linkage. The parallel linkage is assisted by the first air cylinder. The arm-type assistance device further includes a controller that is configured to control pressure of first air cylinder. The third arm includes a second air cylinder. The controller controls pressure of the second air cylinder. A dimension in an axial direction of the second arm is greater than a dimension in an axial direction of the first arm.

Abstract: An arm-type support device includes a first frame, a second frame, a first arm member, a second arm member, and an actuator. The actuator includes a driving unit, an actuating rod, and a link member. The first arm member, the second arm member, the first frame, and the second frame form a parallel link. The first arm member is hollow and accommodates the actuator and the second arm member.

Abstract: An arm-type support device includes a first frame, a second frame, a first arm member, a second arm member, and an actuator. The actuator includes a driving unit, an actuating rod, and a link member. The first arm member, the second arm member, the first frame, and the second frame form a parallel link. The first arm member is hollow and accommodates the actuator and the second arm member.

Abstract: A method for determining position is disclosed, one that is highly reliable in determining a digging position. This method involves the capacity to sense, on the ground, an AC magnetic field generated by a coil housed in a digging head even when there are other noise magnetic fields present that could affect position determination. This method is used in a non-open-cut (boring or trenching) dig. It senses the senses the AC magnetic field provided from a magnetic field source by means of an above-ground magnetic sensor and calculates the position of the magnetic field source from the magnitude and direction of the sensed AC magnetic field.

Abstract: The invention offers a position determining method that ensures high reliability in the determination of a digging position by sensing on the ground an AC magnetic field generated by a coil housed in a digging head, even in the presence of a noise magnetic field affecting the position determination. This is a digging position determining method in a non-open-cut method of excavation which senses the AC magnetic field provided from a magnetic field source by an above-ground magnetic sensor to calculate the position of the magnetic field source from the magnitude and direction of the sensed AC magnetic field.