EP2848574B1 - Small dismountable and displaceable crane for use on construction sites - Google Patents

Description

The present invention relates to a demountable and displaceable small crane for use on construction sites with attachable in a frame-shaped base mast with boom for a rope or chain hoist with hooks, the base frame laterally at each corner has castors, and wherein the boom at the top of the mast is detachably mounted, with a receptacle for counterweights on the opposite side to the boom and with in the front narrow side of the frame designed as a flat profile tube frame base on a cross member centrally mounted mast, wherein the boom to the mast and the lower frame in a fixed predetermined angle extends outside, and wherein in addition to an outer cross member with a receptacle for counterweights at the other end of the undercarriage, an additional cross member at a distance from the rear narrow side is applied, wherein at least one mast support between this further spaced cross member un d the rear of the mast extends up to this, also with a traction drum.

Such a small crane is from the FR 2 525 999 A 1 known.

There are counterweights used at the back of the frame-shaped base in the receptacle formed there in the form of rectangular profile bars, which are supported by upwardly projecting strap. To drive the guided over a pulley on the mast and boom pull rope is a winch, which is applied for lifting the load on the rear part of the movable frame of the small crane. No motor threaded unit is provided to drive the winch of the small crane. Rather, the drive is done manually.

A collapsible and displaceable small crane is also according to the EP 0 517 997 B1 known. To build the small crane, it is necessary to insert the mast of the crane in a receiving tube, which together with arranged on him support feet on their Have underside additional castors, forms a base. The mast is held by two support struts and has a tubular receptacle, in which the inner end of a receiving arm is inserted, at the outer end of a plate-shaped Aufnehmung a counterweight is suspended.

The construction of the crane can be done easily without support by a third party crane or mobile crane or the like on a construction site, since all individual parts of the crane with a lifting capacity of 300 kg at the 5 meter long jib tip are lighter than 80 kg.

A disadvantage of this small crane, however, is that the boom is structurally complex, which is relatively long with 5 meters and thus has a movable load-carrying device in its longitudinal direction and on its opposite side a device for receiving a counterweight from a firmly connected to the mast Pick-up arm which is connected via a guying device to the boom and at the outer end of the counterweight is attached.

It is insofar given a complex mechanical design to set at a given counterweight whose weight becoming effective according to a changing load of the crane, so that the crane does not tilt. There is no actual overload protection given that automatically switches off the drive of the winch of the pull rope with the load hook as soon as the load to be lifted is too heavy. It must be done in this known crane insofar continue to turn on and off the operation by the operator himself.

Furthermore, it is disadvantageous that the length of the cantilever with e.g. 5 meters is significantly larger than the height of the mast, wherein on the boom a longitudinally movable load bearing in the form of a trolley is arranged. In this respect, considerable forces are already acting on the mast at a relatively low load. In this respect, high counterweights are necessary to avoid tilting the crane.

According to the DE 88 12 534 U1 is a load crane with motor drive for the pull rope drum known with an overload protection for the cable.

By means of an actuating arm, a switch is actuated there, which stops the power supply to the winch motor. This overload protection operates on the principle of a torque arm.

Compared to the small crane according to the EP 0 517 997 B1 The purpose of the present invention is to design a small crane such that the construction of the small crane takes place from structurally simpler, lighter individual parts, which can thus be easily transported and assembled in construction sites in unfinished buildings. In this case, the small crane in particular should be structurally simpler to store with simple means the counterweights, which should prevent tilting of the crane, with an additional purely mechanical, releasable with great certainty overload protection for automatically switching off the winch motor of the cable and thus for safe lifting given to be transported loads.

The constructive simple Kleinkran the FR 2 525 999 A1 according to the type mentioned above with a mast and boom and a simply movable underframe and a receptacle for counterweights on the rear transverse frame of the undercarriage to prevent tilting of the small crane when lifting the load is disadvantageous as the intended recording for a counterweight immediately allows only the application of relatively small counterweights in the form of the profile tubes used for the base on the rear cross member.

If the small crane is to be provided for lifting larger weights and insofar is to be provided with an electric drive or winch motor, the attachable counterweights for preventing the tilting of the crane when lifting the load is not sufficient. Furthermore, the attachment of an overload protection for the winch motor or the proposed transmission of the cable drum is necessary.

Starting from such a collapsible and displaceable small crane of the type mentioned above, the object is to provide this with a motor drive and with an overload protection for it, so that it is suitable for lifting larger loads. Further, with an arrangement for counterweights, which are sufficient to prevent the tilting of the small crane when lifting the load.

To solve this problem, a small crane according to claim 1 is provided.

The Kleinkran also has a subframe formed from bare profile beams, which z. B. can be formed as a rectangular support with a large contact surface, with a high stability of the crane is achieved. The underframe is formed from a flat frame of profile tubes, which are screwed together and wherein on a front cross member in the middle of the mast of the crane is detachably mounted and the rear cross member is preferably made of solid material and there forms a counterweight. The outgoing from the top of the mast boom is, as well as the mast itself, not rotatable, but arranged in a fixed predetermined angle to the base.

About an additional cross member at a distance from the rear narrow side of the undercarriage or extending from about the middle of the two lateral side members crossmember on the one hand, the mast is supported via a mounted there diagonal support on the rear of the mast, on the other hand takes place via this additional central cross member, the storage of a swivel cable winch, on which recordings for the counterweights of the crane are created. The winch rocker is formed from a U-shaped bearing frame with two lateral bearing arms, which are each mounted pivotably on the additional central cross member via pivot joints. At the same time, the cable winch jack carries the cable drum for the cable pull of the load hook and its winch motor.

The overload protection is given in the simplest way insofar as a stop lever for switching off the winch motor is applied to the winch rocker itself, which is biased via a simple return holder in the form of a wire rope or chain hoist against the rear cross member of the undercarriage.

In an acting due to an overload on the traction cable of the drum larger force of the trained as a cable winch U-shaped bearing frame is pivoted upward, but the stop lever due to the bias through the Return holder is pulled by wire rope opposite down. The stop lever acts on an off switch of the winch motor, thus no further lifting of the load takes place.

It is insofar given a simple purely mechanical overload protection of the small crane according to claim 1, which offers the highest safety on construction sites when operating the small crane. At the same time via the designed as a cable winch U-shaped bearing frame, the storage of the counterweights and that at the outer rear end of the crane, ie on the opposite side to the boom. In this respect, large moments of force of the counterweights act on the back of the small crane. The counterweights can be chosen so that they can be pulled up to the construction site in the desired height of the building shell via an outer balcony or a window opening on the built-up small crane without initially provided counterweights.

The arrangement of the traction cable drum and the winch motor and its transmission takes place in particular directly on the additional winch rocker, which is arranged on an additional cross member of the frame-shaped base and there is formed on mounted in hinges lateral bearing arms as loads bearing U-shaped support.

The advantage of the arrangement is that the arrangement of the traction cable drum and the winch motor can be done there such that this unit represents an additional counterweight for the load becoming effective directly on the U-shaped bearing frame. In this respect, counterweights are on the one hand according to the FR 2 525 999 provided on the outer rear cross member of the frame-shaped base, or by corresponding cross member made of solid material and on the other additional counterweights directly on the U-shaped bearing frame. In addition to the weight of this drive unit can recordings for other counterweights can be created on the bearing frame on outer laterally projecting end portions. It is thus possible to handle larger loads.

Furthermore, an advantage of the U-shaped bearing frame is that it is pivotally mounted on the cross member, which extends approximately in the middle of the frame-shaped underframe across this and serves as part of an "overload protection".

The pivoting of the U-shaped bearing frame has been exploited so far to simply create an overload protection for the mounted on the bearing frame winch motor or its transmission.

Advantageous embodiment of the small crane according to claim 1 result from the dependent claims 2-12.

According to claim 2, the underframe of the crane is made of a flat profile tube frame in rectangular elongated shape and has two outer lateral side members and three perpendicular thereto cross member.

According to claim 3, 4 and 5, the bearing of the counterweights in the region of the free ends of the two U-shaped pivotable bearing frame forming bearing arms takes place, which can serve as receptacles of the counterweights indentations or elongated vertically projecting rods. The design of the overload protection results according to the dependent claims 6, 7 and 8. Essential for the construction of the small crane from structurally simple and lightweight items are the formation of the small crane according to claims 9-12.

1. 1. Der zerlegbare Kleinkran ist aus wenigen Bauteilen zusammengesetzt, er ist zerlegbar und mit seinen Einzelteilen auf die jeweilige Baustelle in einem Haus bringbar und schnell zum Kleinkran zusammensetzbar;
2. 2. Der Mast des Kleinkranes ist in der Höhe verstellbar, wobei dieser zweiteilig ist und dessen oberes Profilträgerstück im unteren Profilträgerstück eingesetzt und in der Höhe ausfahrbar ist, so dass die Höhe des Mastes verstellbar und auf die gängigen Raumhöhen im Wohnungsbau einstellbar ist;
   Der Auslegerarm des Krans ist unmittelbar seitlich außen am Mast des Kranes angelegt und in der Länge relativ kurz, so dass sich ergebene Drehmomente der zu befördernden Last, welche auf den Mast wirken, begrenzt sind. Somit ist lediglich eine geringes Gegengewicht am Ende des Lagerrahmens des Kranes anzubringen ist, so dass der Kran nicht kippt.
3. 3. Die Profilträgerstücke des Mastes sind untereinander festlegbar, wobei Bolzen in unterschiedlicher Höhe in fluchtenden Bohrungen des inneren und äußeren Profilsträgerstückes einbringbar sind;
4. 4. Zur Vereinfachung des Kranaufbaus weist dieser lediglich einen einzigen Seilzug zum Anheben der Last auf;
5. 5. Die Überlastsicherung mit aufbringbaren Gegengewichten zur Last ist nicht unmittelbar über einen Aufnahmearm gemäß dem EP 0 517 997 am Mast angebracht, sondern seitlich außen an einem als Wippe verschwenkbaren unteren Lagerrahmen des Kranes, wobei an einem zusätzlichen Querträger seitlich außen gegenüberliegend der Mast mittig befestigt ist. Die verschwenkbare Wippe trägt den Windenmotor und die Seilwinde;
6. 6. Der Windenmotor mit Seilwinde ist auf der verschwenkbaren Wippe gelagert und das Gegengewicht dort unmittelbar am äußeren Ende des Lagerrahmens der Wippe befestigt. Bei Belastung des Seilzuges schwenkt die Wippe nach oben, da der Rahmen der Wippe an einem mittig angeordneten Querträger des Trägerrahmens des Untergestells verschwenkbar gelagert ist und der Seilzug auf die Seilwinde wirkt. Der Querträger ist insofern nach innen vom äußeren Ende des Untergestells versetzt angeordnet und trägt die verschwenkbaren Lagerarme der Wippe. Sobald die Last zu schwer ist, verschwenkt die Wippe mit dem Windenmotor nach oben, wobei ein oberhalb des Motors bzw. der Seilwinde angeordneter Stopphebel ebenfalls mit dem Windenmotor nach oben verschwenkt wird und eine am Stopphebel eingehängte Kette, welche gegenüber dem Untergestell mit ihrem anderen Ende festgelegt ist, gespannt wird, so dass der Stopphebel leicht nach unten geschwenkt und somit der Motor ausgestellt wird;
7. 7. Es werden übliche Windenmotore mit Stopphebel, wie in Baumärkten angeboten, verwendet. Der Stopphebel dient an sich dazu, den Windenmotor anzuhalten, sobald die am Zugseil nach oben geförderte Last zu nah an das obere Ende des Auslegers gelangt;
8. 8. Es werden 2 - 4 Gegengewichte von jeweils 15 Kg verwendet, welche als solche leicht einzeln an die jeweilige Baustelle im Haus mit dem aus seinen bloßen Einzelteilen aufgebauten Kran hebbar bzw. transportierbar sind. Insgesamt wirken als Gegengewicht somit 30 bis 60 oder 70 Kg.
9. 9. Die Gegengewichte sind relativ leicht (15 Kg), so dass Sie mit dem aufgebauten Kleinkran an einem vorstehenden Balkon oder dgl. hochziehbar sind, ohne dass der Kran, welcher noch kein Gegengewicht aufweist, kippt;
10. 10. Der Kleinkran kann zur Beförderung von Lasten in Höhen von 15 m bis 30 m je nach vorhandener Zugseillänge verwendet werden;

He thus derive significant advantages over the Kleinkran according to the FR 2 525 999 A1 , Furthermore summarized in particular the following significant advantages over the small crane according to the EP 0 517 997 B1 :

1. 1. The demountable small crane is composed of few components, it can be dismantled and brought with its individual parts to the respective site in a house and quickly assembled to Kleinkran;
2. 2. The mast of the small crane is adjustable in height, this is in two parts and its upper profile carrier piece used in the lower profile carrier piece and extendable in height, so that the height of the mast is adjustable and adjustable to the usual room heights in housing construction;
   The boom of the crane is applied immediately laterally on the outside of the mast of the crane and relatively short in length, so that resulting torques of the load to be carried, which act on the mast, are limited. Thus, only a small counterweight at the end of the bearing frame of the crane is to install, so that the crane does not tip over.
3. 3. The profile carrier pieces of the mast are mutually fixed, with bolts in different heights in aligned holes of the inner and outer profile carrier piece can be introduced;
4. 4. For ease of crane construction, this has only a single cable to lift the load;
5. 5. The overload protection with attachable counterweights to the load is not directly via a pickup arm according to the EP 0 517 997 attached to the mast, but laterally on the outside of a pivotable as a rocker lower bearing frame of the crane, wherein on an additional cross member laterally outboard opposite the mast is mounted centrally. The swiveling rocker carries the winch motor and the winch;
6. 6. The winch motor with winch is mounted on the pivotable rocker and the counterweight attached there directly to the outer end of the bearing frame of the rocker. When loading the cable, the rocker pivots upwards, since the frame of the rocker is pivotally mounted on a centrally arranged cross member of the support frame of the undercarriage and the cable acts on the winch. The cross member is arranged so far inwardly offset from the outer end of the undercarriage and carries the pivotable bearing arms of the rocker. As soon as the load is too heavy, the rocker with the winch motor pivots upwards, with a above the motor or the winch arranged stop lever is also pivoted with the winch motor up and a chain on the stop lever hinged, which is set relative to the base with its other end, is tensioned, so that the stop lever slightly pivoted down and thus the engine is issued;
7. 7. There are common winch motors with stop lever, as offered in hardware stores used. The stop lever per se serves to stop the winch motor as soon as the load conveyed up on the pull rope gets too close to the upper end of the boom;
8. 8. There are used 2 to 4 counterweights of 15 kg each, which are as such easily liftable individually to the respective construction site in the house with the built up of his bare parts crane or transportable. Altogether counter balance thus 30 to 60 or 70 kg.
9. 9. The counterweights are relatively light (15 kg), so that you can be pulled up with the built-on small crane on a protruding balcony or the like, without the crane, which has no counterweight tilts;
10. 10. The small crane may be used to carry loads at heights of 15 m to 30 m, depending on the length of the tow rope;

The invention will be explained in more detail below with reference to the accompanying drawings of a preferred embodiment of the collapsible crane for use on construction sites, the traction cable on his vertical mast a boom with cable for lifting a load having crane on a traction drum is up and down and has a mechanical overload protection, which switches off the motor drive of the traction cable drum at excessive force on the pull rope. This is done via a specially trained winch rocker, which is applied to a pivotable U-shaped bearing frame, which is pivotable relative to the lower frame of the small crane.

• Figur 1
  Eine perspektivische Ansicht des Kleinkrans gesehen auf dessen Vorderseite und die angrenzende linke Längsseite;
• Figur 2
  Eine weitere perspektivische Ansicht des Kleinkrans nunmehr gesehen auf die Rückseite des Kleinkranes, an welchem der als Seilwindenwippe ausgebildete U-förmige Lagerrahmen des Kranes gegenüber dessen Untergestell verschwenkbar gelagert ist, wobei im Hintergrund die Rückseite von Mast und Ausleger des Kranes zu sehen ist;
• Figur 3
  Eine vergrößerte Darstellung eines Ausschnitts der Rückseite des Kranes gemäß Figur 2, gesehen auf dessen Untergestell und den dort über zwei seitliche Lagerarme an einem Querträger verschwenkbar gelagerten U-förmigen Lagerrahmen, welcher mit Zugseiltrommel und Motorantrieb und einer Überlastsicherung ausgebildet ist mit einer Rückstellhalterung aus einem Drahtseil, welches gegenüber einem in einem Schwenkgelenk an der Seilwindenwippe schwenkbar gelagerten Stopphebel und dem Untergestell verspannt ist und bei einer sich einstellenden Überlast entgegen der Bewegung der Seilwindenwippe auf dieser nach unten gegen einen Motorauschalter verstellt wird.

Show it:

• FIG. 1
  A perspective view of the small crane seen on the front and the adjacent left longitudinal side;
• FIG. 2
  Another perspective view of the small crane now seen on the back of the small crane, on which the trained as winch rocker U-shaped bearing frame of the crane relative to the base frame is pivotally mounted, in the background, the back of the mast and boom of the crane can be seen;
• FIG. 3
  An enlarged view of a section of the back of the crane according to FIG. 2 , Seen on the undercarriage and the there about two lateral bearing arms on a cross member pivotally mounted U-shaped bearing frame, which is formed with traction drum and motor drive and overload protection with a return holder of a wire, which is opposite to a in a Swivel joint on the cable winch rocker pivotally mounted stop lever and the base frame is braced and is adjusted at a self-adjusting overload against the movement of the cable winch rocker down on this against a motor switch.

In the perspective view of the small crane (1) can be seen in FIG. 1 the representation of the front and the adjacent left longitudinal side of the crane, which consists of a subframe (2), which is formed from profiled beams (9, 10, 11; 26, 27) in the form of a rectangle, and one of the front narrow side (7) of the underframe on a front cross member (9) centrally arranged mast (3) with extending from the mast top extension arm of a boom (4). Further comprising a pivotally mounted cable winch, which at the rear part of the underframe (2) and consists of a U-shaped pivotable bearing frame (12).

The base is formed of flat profile tube frame, namely from cross members (9, 10, 11) and lateral side rails (26, 27), which are screwed together, these items are so far easy to be brought into the construction workstation provided in each case. A mobility of the crane is given by the arrangement of steering tubes (6) at the individual four corners of the undercarriage (2).

The outgoing from the mast top extension arm of the boom (4) as the mast (3) itself is not rotatable, but arranged in a fixed predetermined angle relative to the base (2).

About an additional cross member (10), approximately in the middle between the front cross member (9) and the rear outer cross member (100) on the one hand the mast (3) via a suitable diagonal support on Mastrückseite fixed, on the other hand via this additional central cross member ( 10) the mounting of a pivotable cable winch rocker (12, 18, 19) on which recordings (25) are applied for the counterweights of the crane.

The winch rocker is formed from a U-shaped bearing frame (12) with 2 lateral bearing arms (13, 14), which are each pivotally mounted on the additional central cross member (10) via pivot joints (15, 16). The rope winch (12, 18, 19) at the same time carries the traction cable drum (18) for the cable pull or for the traction cable (17) with load hook and its winch motor (19).

An overload protection is given in the simplest way insofar as a stop lever (20) for switching off the winch motor (19) is applied on the cable winch or the cable drum (18), which via a simple return holder (22) in the form of a wire rope (23) or chain is biased against the outer rear cross member (100) of the undercarriage.

In a due to an overload on the pull cable (17) of the drum (18) acting larger force of the cable winch rocker shaped U-shaped bearing frame (12) is pivoted upwards, the stop lever (20) but due to the bias of restoring bracket (22) pulled by wire rope opposite to the bottom. The stop lever acts on an off switch (24) of the winch motor (19), thus no further lifting of the load takes place.

In addition to the mechanical overload protection takes place at the same time formed on the winch rocker U-shaped bearing frame (12), the storage of the counterweights and that at the outer rear end of the crane, where there are shots (25) for these weights. The counterweights are in FIG. 1 . 2 shown as usual 10 kg weights.

The further perspective view of the small crane (1) according to FIG. 2 , seen now on the back of the small crane, or directly on the rear narrow side (8) of the undercarriage with the 2 counterweight pieces arranged there, as well as on the opposite longitudinal side of the crane corresponds to the representation according to FIG. 1 ,

It is particularly clear now the winch rocker (12, 18, 19) to recognize, which consists of the U-shaped bearing frame (12), the Zugseiltrommel (18) and the winch motor (19), wherein the U-shaped bearing frame (12) via its two lateral bearing arms (13, 14) and swivel joints (15, 16) is pivotably mounted on the central cross member (10). It's like in FIG. 1 illustrates to recognize the system of the stop lever (20) above the traction cable drum (18), said lever there in a Swivel joint (21) is mounted and over the wire rope (23) relative to the base frame (2) is clamped.

Spaced to the pivotally mounted U-shaped bearing frame (12) is in the background of the underframe (2) on the front narrow side (7) of the crane on the local cross member (9) centrally mounted mast (3) of the crane to recognize and the boom of his Jib (4).

An enlarged view of a section of the back of the crane is in FIG. 3 reproduced, seen directly in the direction of the underframe (2) and the two lateral bearing arms (13, 14) of the U-shaped bearing frame (12), which on the cross member (10) via pivot joints (15, 16) on the cross member (10) pivotally are stored. It is clear to see the traction cable drum (18) and the motor drive (19) and the construction of the overload protection from a restoring bracket (22), a wire rope (23) which between the in a pivot joint (21) on the cable rocker or laterally Tensioning drum (18) pivotally mounted stop lever (20) and the underframe (2) is braced. In this respect, in a self-adjusting overload against the movement of the winch rocker stop lever (20) is pivoted down against the motor switch (24) and thus turned off the engine. References list small crane 1 undercarriage 2 mast 3 boom 4 Base-corners 5 castors 6 front narrow side of the undercarriage 7 rear narrow side of the undercarriage 8th front cross member 9 spaced cross member 10 mast support 11 U-shaped bearing frame (cable winch) 12 Bearing arms of the bearing frame 13, 14 Swivel joints of the bearing arms 15, 16 Traction rope of the crane 17 Traction rope drum (winch) 18 Windmotor 19 stop lever 20 pivot 21 Restoring bracket 22 Wire rope 23 Switch off the engine 24 Shooting for the counterweights 25 longitudinal beams 26, 27 central pipe section of the bearing frame (12) 28 protruding end sections 29, 30 guide plate 31 outer cross member 100

Claims (12)

1. Demountable and mobile small crane (1) for use on building sites comprising a mast (3) with jib (4) that is fixable in a frame-like undercarriage (2), wherein the undercarriage comprises lateral guide rollers (6) at each corner (5) and wherein the jib (4) is releasably mounted at the upper end of the mast, and also comprising seatings (25) for counterweights at the side opposite the jib (4),
   with a mast (3) mounted centrally on a cross beam (9) in the region of the front narrow side (7) of the undercarriage (2) which is in the form of a flat profiled-tube framework, wherein the jib (4) extends outwardly from the mast (3) and the undercarriage (2) at a fixed predeterminable angle, wherein,
   in addition to an outer cross beam (100) incorporating a seating for counterweights at the other end of the undercarriage (2), an additional cross beam (10) is arranged at a spacing from the rear narrow side (8) thereof, wherein at least one mast support (11) extends upwardly between this further spaced cross beam (10) and the rear face of the mast, and further comprising a hoisting cable drum (18)
   characterized in that
   a winch motor (19) for driving the hoisting cable drum (18) is arranged thereon and furthermore there is arranged a U-shaped supporting framework (12) in the form of a pivotal cable winch rocker member having additional seatings (25) for counterweights, the framework being pivotally mounted by means of a respective pivot joint (15, 16) on the spaced additional cross beam (10) by two lateral bearing arms (13, 14),
   and in that the hoisting cable drum (18) for winding and unwinding a hoisting cable (17) of the crane (1) is arranged together with its winch motor (19) on the supporting framework (12) as a further counterweight and a stop lever (20) which serves as an actuating arm for switching off the winch motor (19) and is mounted in a pivot joint (21) is arranged above the hoisting cable drum (18) and as an overload safety device is braced according to a predetermined length with respect to the rear outer cross beam (100) or an adjacent region of the undercarriage (2) by a retaining means (22) in the form of a wire rope (23) or a chain
   and, in the event of a large force that acts on the hoisting cable (17) of the hoisting cable drum (18) due to an overload, the stop lever is pivotable upwardly from the plane of the undercarriage or from a plane parallel thereto with the supporting framework (12) in the form of a cable winch rocker member,
   wherein, due to its retention with respect to the outer cross beam (100), the stop lever (20) is pivotable simultaneously oppositely against a circuit breaker (24) arranged in the switching area and thus switches off the winch motor (19) of the hoisting cable drum (18).
2. Small crane in accordance with Claim 1, characterized in that
   the undercarriage (2) formed from a flat profiled-tube framework is rectangular in elongate shape and consists of two outer lateral longitudinal beams (26, 27) and the cross beams (9, 10, 100) perpendicular thereto.
3. Small crane in accordance with Claim 1 or 2, characterized in that
   the seatings (25) for the counterweights of the supporting framework are arranged in the area at the outer free ends of the bearing arms (13, 14) for the purpose of holding the counterweights.
4. Small crane in accordance with Claim 3, characterized in that
   the U-shaped supporting framework (12) consists of the two outer bearing arms (13, 14) and, connecting them at the free ends thereof, a tube-piece (28) on the upper surface of which there are arranged, in laterally-projecting end sections (29, 30), the seatings (25) for the counterweights of the supporting framework with retaining means therefor.
5. Small crane in accordance with Claim 4, characterized in that
   the tube-piece (28) with the laterally projecting end sections (29, 30) is formed from a flat square tube on the upper surface of which retaining spindles in the form of elongate rods are arranged thereby forming the retaining means for counterweights incorporating mounting holes.
6. Small crane in accordance with Claim 5, characterized in that
   the U-shaped supporting framework (12) in the form of a cable winch rocker member incorporating the internally located bearing arm (13) and the end section of the tube-piece (28) connecting the bearing arms extends over the centre of the width of the undercarriage (2), wherein the mounting of the winch motor (19) and the hoisting cable drum (18) is effected in such a manner that the hoisting cable drum (18) for winding and unwinding the hoisting cable (17) of the crane is arranged in the central region of the undercarriage (2), the cable running over a guide roller on the upper jib (4) of the mast (3), and furthermore the winch motor (19) does not project laterally beyond the undercarriage (2) or the lateral side members (26, 27).
7. Small crane in accordance with Claim 6, characterized in that
   the hoisting cable drum (18) and the winch motor (19) are arranged on a common rotational axis of the unit.
8. Small crane in accordance with Claim 6 or 7, characterized in that,
   at least over the length of the region of the hoisting cable drum, it comprises a bent guidance plate (31) at the outer side of the supporting framework (12) on the central tube-piece (28) or an additional cross beam between the lateral bearing arms (13, 14) (Figure 1).
9. Small crane in accordance with one or more of the Claims 1 to 8,
   characterized in that
   the mast (3) is in two-piece form and consists of two profiled longitudinal sections which are insertible and fixable to one another.
10. Small crane in accordance with Claim 9,
    characterized in that
    the upper profile longitudinal section is insertible into the lower profile longitudinal section and is configurable as a mast (3) which is extendable to different heights.
11. Small crane in accordance with one or more of the Claims 1 to 10,
    characterized in that
    the jib (4) has a length of 50 cm.
12. Small crane in accordance with one or more of the Claims 1 to 11,
    characterized in that
    2 - 4 counterweights each of 10 - 15 kg are provided (total counterweight is thus 30 - 60 kg) for the seatings (25) of the small crane on the U-shaped supporting framework (12) of the cable winch rocker member.

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