Mobile crane having a separable a frame

The disclosure relates to a mobile crane, such as a crawler crane, comprising an undercarriage having a traveling gear, a superstructure rotatably supported about a vertical axle on the undercarriage, a boom connected in an articulated manner to the superstructure pivotable about a horizontal axle, an A frame connected to the boom via a guying means, and a retraction mechanism by means of which the A frame is pivotable. In accordance with the disclosure, the A frame is separable and comprises a pole connected in an articulated manner to the superstructure and a folding pole releasably connected to the pole.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to German Patent Application No. 20 2020 104 192.4 filed on Jul. 21, 2020. The entire contents of the above-listed application is hereby incorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to a mobile crane, such as a crawler crane, and to a separable A frame for said crane.

BACKGROUND AND SUMMARY

In many mobile cranes, for instance in crawler cranes, it is known to guy the main boom via a guying frame or A frame pivotably connected in an articulated manner to the superstructure and to pivot the unit of boom and A frame by means of a retraction mechanism.

FIG.1shows in a side view a crawler crane1known from the prior art having an undercarriage2with a crawler travel gear, a superstructure3rotatably supported thereon about a vertical axle and having an operator's cabin4arranged in the front region, having a superstructure ballast6arranged in the rear region, and a main boom6pivotably supported about a horizontal axle. A load suspension means or lifting hook7is connected via a hoist rope8to a hoist rope winch9supported at the superstructure3. An A frame10connected to the main boom6via retention rods12is connected in an articulated manner to the superstructure3pivotable about a horizontal axle.

The retraction mechanism typically comprises a retraction winch20arranged at the superstructure3and having a retraction rope21that is guided over a roller or roller set24arranged at the end of the A frame and over a roller or roller set22arranged at the superstructure3. The distance between the rollers or roller sets22,24can be reduced/increased by retracting/letting out the retraction rope21by means of the retraction winch20and the A frame10and the boom6can thereby be pivoted.

The main boom6together with the A frame10and the retention rods12forms an adjustment unit that is actuated by the retraction winch rope drive. The free length of the hoist rope8can be changed by actuating the hoist rope winch9and lifting loads attached to the load hook7can thereby be raised or lowered. In some cranes, a derrick boom pivotably connected in an articulated manner at the superstructure3is provided in addition to the main boom6, with the A frame10in this case not being connected to the main boom6, but rather to the derrick boom via the retention rods12.

The base unit of undercarriage and superstructure is typically transported to the deployment site without the crawler carrier and the superstructure ballast and together with the A frame and is assembled on site. The A frame's own weight here substantially contributes to the total weight of the transported unit, which may be problematic with respect to provisions on the maximum permitted transport weight during (road) transport—such as in countries having strict regulations in this respect. A removal of the total unit of A frame and retraction mechanism is also disadvantageous since the attachment and removal is comparatively complicated and time consuming and there is a risk of damage to sensitive components of the retraction mechanism on the attachment and removal or on transport.

Against this background, it is an underlying object of the present disclosure to provide a mobile crane having an A frame that has a transportable unit of the base device with reduced weight and small assembly effort.

This object is achieved in accordance with the disclosed crane having the features of the following description. A mobile crane, such as a crawler crane, comprises an undercarriage having a traveling gear, a superstructure rotatably supported about a vertical axle on the undercarriage, a boom connected in an articulated manner to the superstructure pivotable about a horizontal axle, an A frame connected in an articulated manner to the superstructure pivotable about a horizontal axle and connected to the boom via a guying means, and a retraction mechanism, with the A frame being pivotable by means of the retraction mechanism. In accordance with the disclosure, the A frame is designed as separable, i.e. dismantlable for transport, and comprises a pole pivotably connected in an articulated manner to the superstructure and a folding pole releasably connected to the pole.

Since the A frame can be dismantled into a pole and a folding pole in accordance with the disclosure, it is possible only to remove a part of the A frame, such as the pole, for transport and to leave the other part, such as the folding pole, on the superstructure together with the retraction mechanism. It is thus possible to disassemble the base unit typically disassembled for transport into an even smaller and lighter transport unit without likewise having to remove the retraction mechanism, which simplifies and accelerates the assembly procedure. In addition, sensitive and expensive components of the retraction mechanism are protected against handling and transport damage.

The part of the A frame removable for transport can be removed fast and simply, is compact, and therefore requires a small transport volume. Substantial transport advantages with respect to costs, permits from authorities, for instance in countries with strict regulations with respect to the maximum transport weight, result from the reduced transport weight of the disassembled base unit.

The term “folding pole” is to be given a wide interpretation and does not necessarily require that this part is designed as foldable. It can here be any desired part of the A frame that can remain on the superstructure after the removal of the pole. The boom and the A frame can be pivotable about the same axles or about different axles. The boom can be the main boom or a derrick boom.

Provision is made in an embodiment that the folding pole can be removed from the pole and can be releasably mounted to the superstructure. The pole is therefore removed for transport and is transported separately while the folding pole is reversibly fastened to the superstructure and is transported together with it.

Provision is made in a further embodiment that the components of the retraction mechanism fastened to the A frame are arranged at the folding pole. It is thereby possible to leave the part of the A frame connected to the retraction mechanism on the superstructure for transport and to remove and separately transport the remainder of the A frame, namely the pole. A fast and simple disassembly or assembly of the A frame thus results. The components of the retraction mechanism do not have to be removed from the structures bearing them.

Provision is made in a further embodiment that the retraction mechanism comprises a retraction winch arranged at the superstructure, a first roller set arranged on the superstructure, and a second roller set arranged on the folding pole. The retraction rope can be guided about the roller sets by multiple winding. The second roller set is, in certain embodiments, arranged at the outer end of the A frame. The folding pole can thereby be small and only comprise the structure of the A frame surrounding the second roller set and bearing it so that the majority of the A frame is removable in the form of the pole and the weight of the remaining transport unit can be considerably reduced.

Provision is made in a further embodiment that the folding pole forms the end of the A frame spaced apart from the articulated connection axle and may have connection means for fastening the guying means. The connection means can be located on the side (upper side) of the A frame facing the boom. They can here be pinning points for fastening retention rods.

Provision is made in a further embodiment that the pole can be removed from the superstructure and from the folding pole and can be transported separately, with the retraction mechanism remaining on the superstructure. The connection between the pole and the folding pole and the connection of the pole to the superstructure is released for this purpose.

Provision is made in a further embodiment that the folding pole and the superstructure each have fastening means by means of which the folding pole can be releasably mounted on the superstructure, with the fastening means of the superstructure being arranged in its rear region and the fastening means of the folding pole being arranged on the side (lower side) of the A frame remote from the boom. They can here be pinning points for establishing releasable pin connections. The folding pole only has to be downwardly pivoted or folded way about a horizontal axle to join the fastening means together in this advantageous arrangement and the joined together fastening means only subsequently have to be connected. The remaining connection to the pole can then be released and the latter can be removed from the superstructure. The pivoting of the folding pole can take place with the aid of an auxiliary crane.

Provision is made in a further embodiment that the folding pole is connected to the pole pivotable about an axle that is horizontal (pivot axle) and is latchable thereto, with this axle and the latching connection each being releasable pin connection. The latching connection can take place along an axle (latching axle) in parallel with the pivot axle. The pole and the folding pole can each have connection means, such as pinning points, for this purpose. The folding pole can be pivoted about the pivot axle relative to the pole by releasing the connection to the latching axle.

Provision is made in a further embodiment that the fastening means of the folding pole and superstructure can be joined together by pivoting the folding pole about the axle (pivot axle). The connection between the pole and the folding pole along the pivot axle can be released after the establishment of the connection of the fastening means. The pivoting of the folding pole can take place with the aid of an auxiliary crane.

Provision is made in a further embodiment that the pole is longer than the folding pole. The majority of the A frame can thereby be removed for transport and the weight of the transport unit can be considerably reduced. Provision can alternatively or additionally be made that the pole and the folding pole substantially have the same width. The A frame can, however, also have a base shape tapering toward the end. In this case, the pole and the folding pole at least substantially have the same width at the connection points.

Provision is made in a further embodiment that the A frame has a rack-like structure having two side members that are in particular in parallel and having at least one cross member that connects the side members, with at least one cross member being arranged at the folding pole. The side members can alternatively converge toward one another toward the folding pole.

Provision is made in a further embodiment that that guying means comprises one or more rigid guying rods each pivotably fastened to the boom and to the A frame.

The present disclosure furthermore relates to a separable A frame for a mobile crane in accordance with the disclosure. In this respect, the same advantages and properties obviously result as for the crane in accordance with the disclosure so that a repeat description will be dispensed with at this point.

DETAILED DESCRIPTION

FIG.1shows a crawler crane1of the category having an A frame10in a side view and has already been initially described in detail. Repeat descriptions are therefore dispensed with. The mobile crane in accordance with the disclosure can be such a crawler crane1, with the A frame10being separable in comparison with units of the category.

FIG.2shows in a side view a detail of the superstructure3in accordance with an embodiment of the crane1in accordance with the disclosure that is a crawler crane1in accordance withFIG.1. In accordance with the disclosure, the A frame10is separable or dismantlable and comprises a pole144connected to the superstructure3pivotable about a horizontal axle A2and a folding pole16that is releasably fastened thereto and that forms the end of the A frame10spaced apart from the axle A2. The boom6, that is the main boom of the crane1in the present embodiment, is a horizontal axle A1spaced apart from the axle A2.

The A frame10is adjustable or pivotable via an actuation of a retraction mechanism, with the retraction mechanism comprising a retraction winch20arranged on the superstructure3, a first roller set22arranged at the rear end of the superstructure3, and a second roller set24fastened to the folding pole16. A retraction rope21that is supported in a windable and unwindable manner on the retraction winch20is guided or wound multiple times around the roller sets22,24The distance between the roller sets22,24can be reduced and the A frame can thereby be pivoted to the rear/downwardly by winding up the retraction rope21. The reverse movement takes place on the unwinding due to the weight of the boom6coupled to the A frame10via the retention rods12in working operation. In one embodiment, the A frame10may have a rack-like structure having a first side member30and a second side member in parallel and having at least one cross member32being arranged at the folding pole.

The A frame10or the pole14and folding pole16can comprise two outer side members, with the second roller set24being supported between the outer side members of the folding pole16. The pole14and the folding pole16each have connection means26,27by which they are releasably connected or connectable to one another. The connection means26,27are here designed as pinning points via which two parallel pin connections can be established. In some aspects, the folding pole forms the end of the A frame spaced apart from the articulated connection axle and may have connection means as shown by arrow34for fastening the guying means. The connection means can be located on the side (upper side) of the A frame facing the boom.

The A frame10is pivoted downwardly for the removal of the pole14from the superstructure3for the purpose of transport so that it substantially contacts the superstructure3(cf.FIG.2). By releasing the upper one of the two pin connections (latching axle) between the pole14and the folding pole16, the latter can be pivoted or folded downwardly in the direction of the superstructure3about the lower pin connection that forms a horizontal pivot axle A3. The pivoting of the folding pole16about the axle A3can take place by means of an auxiliary crane. The second roller set24here moves slightly relative to the first roller set22.

Fastening means18formed as pinning points are located at the side remote from the boom6or at the lower side of the folding pole16. Such fastening means19are likewise arranged at the rear end or in the rear region of the superstructure3. By pivoting the folding pole16about the axle A3, the former rotates with respect to the superstructure3and the fastening means18,19are joined together, i.e. the pinning points are brought into alignment. The folding pole16is fastened to the superstructure3by pinning the fastening means18,19so that the pin connection to the pole (axle A3) can now be released. It is conceivable here that the now released pins of the released upper pin connection (latching axle) between the pole14and the folding pole16can be used for the pin connection of the fastening means18,19. Separate pins can, however, also be used.

Once the folding pole16has been mounted on the superstructure3and the pin connection to the pole14has been released, the pole14can be dismantled from the superstructure3. Since the pole14itself does not bear any component of the retraction mechanism, the latter remains completely at the superstructure3and can be transported together with it.

FIG.3shows the superstructure3in the transport position after removal of the pole14, with the folding pole16being supported at its rear. Since the pole14is substantially larger or longer than the folding pole16that only forms the tip of the A frame10, the transport weight of the remaining unit can be considerably reduced by dismantling the pole14. In some aspects, the pole and the folding pole may substantially have the same width. The A frame can, however, also have a base shape tapering toward the end. In this case, the pole and the folding pole at least substantially have the same width at the connection points as shown by14and16inFIG.2. The removal itself can take place simply and fast since no complicated parts have to be dismantled. The removal is also simpler and more damage safe than the dismantling of the total A frame10including the retraction mechanism. The pole14itself is compact and therefore only requires a small transport volume.

A method of dismantling the pole14for the purpose of forming a light transport unit could comprise the following steps: lowering the A frame10, releasing the guying means12from the A frame10, releasing the upper (pin) connection between the pole14and the folding pole16, pivoting the folding pole16about the lower pin connection A3, optionally by means of an auxiliary crane, connecting or pinning the fastening means18,19of the folding pole16and the superstructure3that have been pivoted together, releasing the lower (pin) connection A3between the pole14and the folding pole16, removing the pole14(such as by releasing the connection at the axle A2to the superstructure3), optionally by means of an auxiliary crane. These steps are run through in reverse order for the assembly of the pole14.

The A frame10in accordance with the disclosure can also simply be retrofitted to existing cranes1. The fastening means19for fastening the folding pole16only have to be attached at the suitable point at the rear of the superstructure3for this purpose and the second roller set24has to be mounted on the folding pole16.

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