Abstract: The overhanging storage mechanism for a jib is provided with: a guide roller (31) provided to a jib (15); a guide (32) provided to a base end boom (14a); a jib-fixing pin (43) provided to the base end boom (14a); and a pin socket (45) that is provided to the jib (15) and that comprises insertion holes (48), (49). The jib-fixing pin (43) and the insertion holes (48), (49) are arranged so that the jib-fixing pin (43) is inserted in the insertion hole (48) when the jib (15) moves along the base end boom (14a) together with contraction of a boom (14). The inner dimensions of a front end opening (48) are larger than the outer dimensions of the jib-fixing pin (43). It is thus possible to absorb positional displacement between the jib-fixing pin (43) and the insertion hole (48).

Abstract: The overhanging storage mechanism for a jib is provided with: a guide roller (31) and a pin socket (45) that are provided to a jib (15); and a guide (32) and a jib-fixing pin (43) that are provided to a base end boom (14a). The guide (32) comprises a first raceway surface (34s) that pulls the jib (15) toward the bottom surface of the base end boom (14a) as a result of rolling of the guide roller (31), a second raceway surface (35s) on which the jib (15) moves along the base end boom (14a), and a protruding third raceway surface (36s) that protrudes from the second raceway surface (35s). The jib (15) is pulled further toward the bottom surface of the base end boom (14a) by rolling of the guide roller (31) on the third raceway surface (36s).

Abstract: Provided is a jib connection structure for restraining a projectable/retractable jib from swinging sideways in a state where the jib is suspended from a boom tip end part, the jib connection structure including: jib connection shafts projecting horizontally toward both sides from a boom tip end part; and jib base end engagement parts respectively provided to bifurcated jib base end parts. Each jib base end engagement part is U-shaped into which the jib connection shaft can be fitted, and is provided with an insertion hole into which a pin for preventing the jib connection shaft from slipping out is inserted. The insertion hole in one jib base end engagement part is arranged more toward the outside than a U-shaped bottom part. When a jib is suspended from the boom tip end part, the left and right pins engage with the respective jib connection shafts, and the jib is suspended at two points.

Abstract: Provided is a jib connection structure capable of connecting a jib base end engagement part and a jib connection shaft even when a boom undergoes natural extension, and capable of restraining a jib from swinging sideways in a state where the jib is projected. This jib connection structure includes: jib connection shafts projecting horizontally toward both sides from a boom tip end part; and jib base end engagement parts respectively provided to bifurcated jib base end parts. Each jib base end engagement part is U-shaped into which the jib connection shaft can be fitted, and is provided with an insertion hole into which a pin for preventing the jib connection shaft from slipping out is inserted. When the jib base end engagement part and jib connection shaft are connected, a gap is formed between the pin and jib connection shaft. When a jib is projected, the gap becomes smaller.

Abstract: The overhanging storage mechanism for a jib is provided with: a guide roller (31) provided to a jib (15); a guide (32) provided to a base end boom (14a); a jib-fixing pin (43) provided to the base end boom (14a); and a pin socket (45) that is provided to the jib (15) and that comprises insertion holes (48), (49). The jib-fixing pin (43) and the insertion holes (48), (49) are arranged so that the jib-fixing pin (43) is inserted in the insertion hole (48) when the jib (15) moves along the base end boom (14a) together with contraction of a boom (14). The inner dimensions of a front end opening (48) are larger than the outer dimensions of the jib-fixing pin (43). It is thus possible to absorb positional displacement between the jib-fixing pin (43) and the insertion hole (48).

Abstract: The overhanging storage mechanism for a jib is provided with: a guide roller (31) and a pin socket (45) that are provided to a jib (15); and a guide (32) and a jib-fixing pin (43) that are provided to a base end boom (14a). The guide (32) comprises a first raceway surface (34s) that pulls the jib (15) toward the bottom surface of the base end boom (14a) as a result of rolling of the guide roller (31), a second raceway surface (35s) on which the jib (15) moves along the base end boom (14a), and a protruding third raceway surface (36s) that protrudes from the second raceway surface (35s). The jib (15) is pulled further toward the bottom surface of the base end boom (14a) by roiling of the guide roller (31) on the third raceway surface (36s).

Abstract: Provided is a jib connection structure for restraining a projectable/retractable jib from swinging sideways in a state where the jib is suspended from a boom tip end part, the jib connection structure including: jib connection shafts projecting horizontally toward both sides from a boom tip end part; and jib base end engagement parts respectively provided to bifurcated jib base end parts. Each jib base end engagement part is U-shaped into which the jib connection shaft can be fitted, and is provided with an insertion hole into which a pin for preventing the jib connection shaft from slipping out is inserted. The insertion hole in one jib base end engagement part is arranged more toward the outside than a U-shaped bottom part. When a jib is suspended from the boom tip end part, the left and right pins engage with the respective jib connection shafts, and the jib is suspended at two points.

Abstract: Provided is a jib connection structure capable of connecting a jib base end engagement part and a jib connection shaft even when a boom undergoes natural extension, and capable of restraining a jib from swinging sideways in a state where the jib is projected. This jib connection structure includes: jib connection shafts projecting horizontally toward both sides from a boom tip end part; and jib base end engagement parts respectively provided to bifurcated jib base end parts. Each jib base end engagement part is U-shaped into which the jib connection shaft can be fitted, and is provided with an insertion hole into which a pin for preventing the jib connection shaft from slipping out is inserted. When the jib base end engagement part and jib connection shaft are connected, a gap is formed between the pin and jib connection shaft. When a jib is projected, the gap becomes smaller.