Kabushiki Kaisha Kobe Seiko Sho

Yukio Koizumi

Hiroshi Miyazawa

Takahiro Kobayashi

Norihiko Hayashi

Tsuyoshi Katada

Shunsuke Yokoyama

A jib stretching and folding device is used in a crane having a jib for increasing a lift of the crane, the jib being stretchable from a folded position along a side surface or a lower surface of a boom through a vertically suspended position. The jib stretching and folding device has a jib maneuvering cylinder, an engaging portion formed in a piston rod of the cylinder, an engaging member provided on the jib, and a guide surface formed at at least either of the engaging portion or the engaging member for guiding the engaging member so as to engage with the engaging portion. The jib is made movable between the vertically suspended position and the folded position by way of extension and contraction of the piston rod.

Jib stretching and folding device for use in a crane

A crane having a boom and a jib swingable on the boom between a taken in position and a stretched out position includes a jib holding construction. A jib hold rod is movably mounted on the jib between a first position in which a base end of the jib hold rod is connected to the jib when the jib is in the taken in position, and a second position in which the base end of the jib hold rod is connected to a portion of the boom for supporting the jib in the stretched out position. A rod holding link is mounted to the jib for selectively holding the base end of the jib hold rod at a correct position for connection to the boom when the jib is swung out to the stretched out position. This avoids the need to manually locate the jib hold rod in the second position when the jib is stretched out.

Jib hold rod securing device for cranes

A jib stretching and folding device including an auxiliary connector mounted on a lower surface of a jib in the vicinity of a base end portion ofo the jib in a jib folded condition. The auxiliary connector includes a cylindrical housing fixed to the lower surface of the jib and a connecting rod rotatably supported by the housing and having an axis which is substantially parellel to the lower surface of the jib. The jib is twisted about the axis of the connecting rod to effect a jib stretching or folding operation. A twist guiding groove is formed on one of the housing and the connecting rood of the auxiliary connector, and an engagement projection is provided on the other of the housing and the connecting rod to engage the twist guiding groove. When the jib is raised or lowered by a jib raising/lowering means, the engagement projection is moved in the twist guiding groove to generate a jib twisting force. Thus, the jib is automatically twisted in the jib stretching or folding operation. Accordingly, a burden of labor of an operator in stretching and folding the jib can be reduced. Further, the operation can be made continuous to thereby improve the efficiency of the jib stretching and folding operation.

Jib stretching and folding device for crane

A device for stretching and folding a strut type jib for a crane, including a jib supporting mechanism for supporting the jib along one side surface of a boom under a vertically disposed condition of the jib where a forward end portion of the jib is directed to a forward end portion of the boom, and opposite flat planes of the jib are oriented horizontally in such a manner that the jib is slidable along the side surface of the boom in a range between a folded position of the jib where a base end portion of the jib is disposed aside a base end portion of the boom and an advance position of the jib where the base end portion of the jib is disposed aside the forward end portion of the boom; a pair of jib supporting shafts projecting outwardly from opposite side surfaces of the forward end portion of the boom; a pair of connecting portions provided at the base end portion of the jib and adapted to be connected to the jib supporting shafts upon stretching of the jib; and an engaging member provided at a lower end portion of the base end portion of the jib under the vertically disposed condition of the jib in such a manner that the jib is rotatable about a longitudinal axis of the jib. The engaging member is brought into engagement with one of the jib supporting shafts projecting from one of the opposite side surface of the forward end portion of the boom on the same side as the one side surface of the boom, at the advance position of the jib.

Method for stretching and folding a jib for crane

A steering controlling device for a wheel crane wherein a locking operation in a special mode is permitted upon changing over from the special mode to a normal mode and locking and a mode changing over operation can be prevented during normal running of the crane. The device includes front and rear wheel steering cylinders, a mode changing over valve for controlling the cylinders to change over the steering mode, a mode selecting switch, a locking device for locking the rear wheels in the normal mode, a locking switch, a running detecting sensor for detecting a running condition of the crane, a locking change-over controller means responsive to signals from the locking switch and the running detecting sensor for developing a locking or unlocking instruction signal to the locking device when the crane is not in a normal running condition, and a mode change-over controller means responsive to a signal from the running detecting means for forwarding a steering mode selected by the mode selecting switch to the mode changing over valve when the crane is not in a normal running condition.

Steering controlling device for wheel crane

A jib derricking gear for a jib crane having a boom and a jib for hoisting work extended from the boom head of the boom comprises a pair of jib derricking cylinder actuators. Load on the jib is distributed to the pair of jib derricking cylinder actuators, so that each jib derricking cylinder actuator may be such as having a cylinder having a comparatively small diameter. The jib derricking cylinder actuators are combined with the jib so that the jib derricking cylinder actuators function as compression members. The thrust of the jib derricking cylinder actuator is doubled by a tackle. The jib derricking cylinder actuators and the associated jib supporting members are disposed so that the jib derricking cylinder actuators and the associated jib supporting members will not interfere with a hoist rope for hoisting work.

Jib derricking gear for a crane

In a crane capable of folding a strut type jib along a vertical side surface of a boom and also capable of stretching the jib from such a folded condition in a so-called twisting fashion, a jib stretching and folding device includes a twist shaft for jib stretching and folding operation located below a lower member of the jib under the jib folded condition, so as to fold the jib at an upper position aside the boom. Furthermore, the twist shaft is movable toward and away from the forward end of the boom, so as to fold the jib at a position shifted to the base end of the boom. The advance condition of the twist shaft to the forward end of the boom can be fixed so as to prevent movement of the jib to the forward end of the boom.

Jib stretching and folding device

A jib stretching and folding mechanism for a jib crane having a boom, a jib pivotally supported at the base end thereof on jib support pins provided at the distal end of the boom, and jib cylinders each having one end pivotally joined to the jib support pin and the other end fixed to the corresponding base end of the jib. The jib stretching and folding mechanism includes guide cylinders each having one end fixedly connected to the piston rod of the jib cylinder so as to be able to receive entirely the cylinder tube of the same jib cylinder as the jib cylinder is contracted, and guide members fixed to the cylinder tubes of the jib cylinders so as to engage guide grooves formed in the corresponding guide tubes, respectively. The guide groove formed in one of the guide tubes has a helical section formed in an angular range corresponding to an angle through which the jib suspended from one of the jib support pins is turned in stretching and in folding the same, so that the jib is turned automatically when the jib cylinders are operated for stretching and for folding the jib by the movement of the guide member along the helical section of the guide groove.

Jib stretching and folding mechanism for a jib crane

A method for stretching and folding an extension jib in a wheeled type crane including a telescopic boom, and a suspension-rod-supported compression column type extension jib to be supported in a flat posture at the fore end of the boom in stretched state through right and left jib foot portions rotatably engaged with horizontal boom point pins extending transversely of the boom at the fore end thereof, the method including the steps of (a) providing on opposite sides of the extension jib right and left jib foot portions disengageably engageable with the boom point pins, one of the jib foot portions being rotatable relative to the boom about an axis extending in the axial direction of the jib; (b) stretching the jib from a folded position in which the top and bottom sides of the jib are disposed in an upright posture along one side of the boom, by engaging the one jib foot portion with the boom point pin on the folding side and turning the boom into an inclined position from a horizontal position, rotating the jib around the axis of the boom point pin into a vertically suspended position; (c) turning the jib in the vertically suspended position through a predetermined angle about the axis extending in the axial direction of the jib to engage the other jib foot portion with the corresponding boom point pin, and stretching the jib in a flat posture; and (d) in the folding operation, folding the jib into the initial folded position by performing steps (a) to (c) in an inverse order.

Method for stretching and folding extension jib in wheeled type crane

An apparatus for stretching and folding an extension jib in a wheeled type crane including a telescopic boom, and a suspension-rod-supported compression column type extension jib to be supported in a flat posture at the fore end of the boom in stretched state through right and left jib foot portions rotatably engaged with horizontal boom point pins extending transversely of the boom at the fore end thereof, the method including the steps of (a) providing on opposite sides of the extension jib right and left jib foot portions disengageably engageable with the boom point pins, one of the jib foot portions being rotatable relative to the boom about an axis extending in the axial direction of the jib; (b) stretching the jib from a folded position in which the top and bottom sides of the jib are disposed in an upright posture along one side of the boom, by engaging the one jib foot portion with the boom point pin on the folding side and turning the boom into an inclined position from a horizontal position, rotating the jib around the axis of the boom point pin into a vertically suspended position; (c) turning the jib in the vertically suspended position through a predetermined angle about the axis extending in the axial direction of the jib to engage the other jib foot portion with the corresponding boom point pin, and stretching the jib in a flat posture; and (d) in the folding operation, folding the jib into the initial folded position by performing steps (a) to (c) in an inverse order.

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Akashi, Japan

Yukio Koizumi