A jib attachment/detachment mechanism to mount a jib on a boom head includes a guide mechanism including a guide roller and a guide support configured to guide engaging portions of a jib support to positions of engagement with shaft pins of a boom head when the jib support is pulled up with a wire by using a winch and to prevent change of a state of the wire pulled up by the winch when the jib support is rotated around the shaft pins by contracting a cylinder.

A portable winch and method of use is shown. One advantage of winches shown includes an ability to lower a boom or boom sections into limited access exit pit for winching operations such as pipe bursting. Sectional boom designs shown provide the ability to easily raise and lower a boom large distances without the need for a single long boom. Selected winch designs shown include flexible inserts between the boom and the winch frame that help resist damage from unforeseen shifting of the device during operation. Designs and methods shown also include multiple pulleys on a boom end unit. Fasteners are shown that reduce build up of debris.

A portable winch and method of use is shown. One advantage of winches shown includes an ability to lower a boom or boom sections into limited access exit pit for winching operations such as pipe bursting. Sectional boom designs shown provide the ability to easily raise and lower a boom large distances without the need for a single long boom. Selected winch designs shown include flexible inserts between the boom and the winch frame that help resist damage from unforeseen shifting of the device during operation. Designs and methods shown also include multiple pulleys on a boom end unit. Fasteners are shown that reduce build up of debris.

A marine knuckle boom crane includes a crane housing which is rotational relative to a pedestal about a vertical rotation axis and a knuckle boom assembly attached to the crane housing. The knuckle boom assembly includes a main boom, the inner end of which is connected pivotably about a first horizontal pivot axis to the crane housing; and a jib, the inner end of which is connected pivotably about a second horizontal pivot axis to the outer end of the main boom, wherein the jib is pivotable at least between an extended position in which the tip extends mainly forward from the main boom, and a folded position in which the jib is folded back, essentially parallel along the main boom. In order to position the jib with respect to the main boom, a tensioning member is provided extending between the crane housing and a curved extension guide connected to the jib.

A marine knuckle boom crane includes a crane housing which is rotational relative to a pedestal about a vertical rotation axis and a knuckle boom assembly attached to the crane housing. The knuckle boom assembly includes a main boom, the inner end of which is connected pivotably about a first horizontal pivot axis to the crane housing; and a jib, the inner end of which is connected pivotably about a second horizontal pivot axis to the outer end of the main boom, wherein the jib is pivotable at least between an extended position in which the tip extends mainly forward from the main boom, and a folded position in which the jib is folded back, essentially parallel along the main boom. In order to position the jib with respect to the main boom, a tensioning member is provided extending between the crane housing and a curved extension guide connected to the jib.

A combination of a first unit and a second unit are to be rotatably interconnected through a pin. The first unit includes a first unit body provided with a first pin hole, a first contact member, and a fastening member. The first contact member has a first contact surface. The second unit includes a second unit body provided with a second pin hole, and a second contact surface. The second contact surface is contactable with the first contact surface. The fastening member fastens the first contact member to the first unit body so as to allow the relative position of the first contact member to the first unit body to be adjusted.

A combination of a first unit and a second unit are to be rotatably interconnected through a pin. The first unit includes a first unit body provided with a first pin hole, a first contact member, and a fastening member. The first contact member has a first contact surface. The second unit includes a second unit body provided with a second pin hole, and a second contact surface. The second contact surface is contactable with the first contact surface. The fastening member fastens the first contact member to the first unit body so as to allow the relative position of the first contact member to the first unit body to be adjusted.

An extension yoke (1), a self-hoisting wind turbine crane (5) with such a yoke a method of using such a yoke are disclosed. The yoke comprises a frame structure comprising a lifting portion (2) and a load transfer portion (3), forming an obtuse angle with each other, and at least one crane attachment element (4) positioned between the load transfer portion and the lifting portion, said at least one crane attachment element being configured for establishing a pivot connection to a crane. The lifting portion comprised a load attachment element (2) and the load transfer portion comprise at least one load transfer element (33), said load transfer element being configured for transferring compressive force by pressing against a reception surface (52) of the crane and for moving in relation to the reception surface. The frame structure may comprise at least two substantially parallel longitudinal beams (12a, 12b), at least one cross-beam (13), and/or at least one stabilisation element (12), and the crane attachment element may comprise a pulley block reception element.

A holding device for use with a telescopically extensible crane boom (57) in order to keep a load handling tool (4) in a given parking position in relation to the crane boom. The holding device (1) comprises: an attachment (10) to be fixed to an end of a telescopic crane boom section of the crane boom; a tool holder (15), which is detachably mountable to the attachment (10) and configured for engagement with the tool in order to support it against the crane boom and keep it in the parking position, the tool holder being provided with a sliding member (28), through which the tool holder is configured to slidably rest against an external surface on the crane boom; and a locking mechanism (16) for locking the tool holder and the attachment to each other when the tool holder is mounted to the attachment.

Provided is a crane with a main boom and a back mast, of which at least one comprises a first mast upper part comprising at least one mast section and a first mast lower part comprising at least one mast section, and a first mast tilting. The first mast tilting member is arranged between the first mast upper part and the first mast lower part, and has a straight hoisting state wherein the first mast upper part and the first mast lower part are essentially in line with each other, and a tilted hoisting state wherein the first mast upper part is tilted with respect to the first mast lower part.