BOOM-ARM SEGMENT AND METHOD FOR PRODUCING A BOOM-ARM SEGMENT

Abstract

The invention relates to a boom-arm segment fora concrete pump, wherein the boom-arm segment (30) comprises a side part (35, 36)-which extends between a top chord (33) and a bottom chord (34) of the boom-arm segment (30). In the side part (35, 36), a bent portion is formed such that a first portion (42, 43) of the side part (35, 36) has a lateral offset (56) relative to a second portion (44) of the side part (35, 36). A transition portion (45, 46) forms a connection between the first portion (42, 43) and the second portion (44). The boom-arm segment (30) comprises a reinforcement part (40, 50), the material thickness of which spans the lateral offset (56) between the first portion (42, 43) and the second portion (44). The reinforcement part (40, 50) is butt-joined to the transition portion (45, 46). The invention also relates to a method for producing a boom-arm segment (30).

Description

BACKGROUND

The invention relates to a boom-arm segment for a concrete pump, and to a method for producing such a boom-arm segment.

Concrete-pump boom arms are utilized for directing a conveyor line connected to a concrete pump such that the liquid concrete conveyed by the concrete pump can be delivered to a region remote from the concrete pump. Such a concrete-pump boom arm is usually assembled from a plurality of boom-arm segments, wherein the sum of the boom-arm segments in an unfolded state defines the length of the boom arm, and wherein the boom-arm segments in a folded-up state are folded up to a compact state for facilitating transportation.

Because it is customary for concrete pumps to be specified such that the liquid concrete is conveyed in pulses, the boom arms are subjected to significant dynamic loads. In addition, the boom-arm segments can be folded in different ways during operation of the concrete pump, depending on from which distance from the concrete pump the liquid concrete is to be delivered. This leads to the tensile and compressive loads acting on a boom-arm segment in very different directions, depending on the operating state of the boom arm. For these reasons, boom-arm segments of a concrete pump are subjected to particular stresses in operation.

SUMMARY

The invention is based on the object of proposing a concrete-pump boom-arm segment and a method for producing a concrete-pump boom-arm segment, so that the concrete-pump boom-arm segment positively withstands the static and dynamic loads, is cost-effective in production, and has a low weight. Proceeding from the mentioned prior art, the object is achieved by the features of the independent claims. Advantageous embodiments are set forth in the dependent claims.

The boom-arm segment according to the invention comprises a lateral part which extends between an upper chord and a lower chord of the boom-arm segment. Configured in the lateral part is a bent edge so that a first portion of the lateral part has a lateral offset relative to a second portion of the lateral part. The lateral part comprises a transition portion which forms a connection between the first portion and the second portion. A reinforcement part of the boom-arm segment has a material thickness which bridges the lateral offset between the first portion and the second portion. The reinforcement part and the transition portion are connected by way of a butt joint.

Reinforcement elements which bear externally on the lateral part are known from the prior art, i.e. DE 10 2017 223 240 A1. This is associated with the disadvantage that the boom-arm segment in the width dimension has a larger extent which is undesirable in many cases. If a reinforcement part is to be connected to the lateral part without such an increase in terms of the width of the boom-arm segment, the lateral offset between the first portion and the second portion of the lateral part has to be bridged in order to make it possible for the reinforcement part to be connected to the first portion as well as to the second portion of the lateral part. It is proposed by the invention that the lateral offset between the first portion and the second portion is bridged by the material thickness of the reinforcement part, and that the reinforcement part and the transition portion are connected by way of a butt joint. An abutment in the context of the invention is a butt joint in which an end face of the transition portion bears on an end face of the reinforcement portion. In other words, the reinforcement part adjoins the transition portion in the longitudinal direction. A straight line which extends in the longitudinal direction of the boom-arm segment within the transition portion intersects the interconnected end faces of the transition portion and of the reinforcement part.

The invention has recognized that the static and dynamic forces which occur in the boom-arm segment can be positively absorbed by such a combination of a reinforcement part and a lateral part. The resistance in relation to buckling deformations is increased by the bent edge in the lateral part, said bent edge extending in the longitudinal direction of the boom-arm segment, so that a lower material thickness can be used for the lateral part in comparison to a planar lateral part without a bent edge. The lower weight which is achieved in this way is of particular importance in the context of the parts of a concrete pump which are very remote from the rotating mechanism, because the concrete pump may capsize if the load torque becomes excessive. Moreover, the components at the bottom can be embodied with lower strength in this instance, because said components do not have to support the additional weight of the parts lying on the outside, which are now lighter. The reinforcement part can adjoin the transition portion of the boom-arm segment in the longitudinal direction and form a region of the boom-arm segment which is conceived for introducing comparatively high forces into the boom-arm segment. For example, an articulated connector fora connection to an adjacent boom-arm segment or to a receptacle for a hydraulic cylinder can be configured in the reinforcement part.

The material of the lateral part can be of such dimensions that said material can absorb the normal loads that occur across the length of the boom arm. In regions of the boom arm in which increased loads occur, such as in the case of joint receptacles, for example, or in the case of receptacles for hydraulic cylinders, the boom-arm segment is reinforced by a reinforcement part, the material thickness of the latter being greater than the material thickness of the lateral part. It is proposed by the invention that the material thickness of the reinforcement part is chosen to be of such a size that the reinforcement part bridges the lateral offset between the first portion and the second portion of the lateral part. In this way, the reinforcement part and the transition portion can be connected by way of a butt joint, thus end face to end face. This furthermore opens up the possibility of achieving a direct connection between the reinforcement part and the lateral part also in regions of the first and the second portion of the lateral part that are contiguous to the transition portion. In this way, this results in a harmonic transition between the reinforced force-introducing region and the bending beam.

The connection between the lateral part and the reinforcement part can be designed as a welded connection. The welded connection can be configured as a butt joint across the entire length of the connection between the reinforcement part and the lateral part, so that an end face of the reinforcement part is welded to an end face of the lateral part. It is also possible that the welded connection comprises portions which are welded butt joints and portions which are welded in an overlapping manner. Those portions of the welded connection which are welded butt joints can comprise the connection to the transition portion of the lateral part as well as other portions.

The welded connection can comprise portions in which those regions of the lateral part and of the reinforcement part that are contiguous to the welded connection lie in mutually parallel planes. This can apply to all portions of the welded connection that are not contiguous to the transition portion of the lateral part. In particular, an overlap between the lateral part and the reinforcement part may be provided in regions in which the reinforcement part and the lateral part are not connected by way of a butt joint. Conversely, the connection can be free of any overlap where the reinforcement part and the lateral part are connected to one another by way of a butt joint.

In one embodiment, the reinforcement part is connected to the first portion of the lateral part by way of a butt joint, and is connected to the second portion of the lateral part in an overlapping manner. The first portion can form a peripheral portion of the lateral part, which peripheral portion is contiguous to the upper chord or the lower chord of the boom-arm segment. The second portion can form a central portion of the lateral part, which central portion is spaced apart from the upper chord and the lower chord. The reinforcement part can be connected to the second portion of the lateral part by a weld seam which extends along a portion of an encircling edge of the reinforcement part. The material thickness of the reinforcement part can be of such a dimension that the reinforcement part does not protrude outward beyond the first portion of the lateral part. It is desirable that no increase in terms of the width of the boom-arm segment is caused by the reinforcement part in comparison to the contour defined by the lateral parts. In one embodiment, the lateral face of the reinforcement part terminates so as to be flush with the first portion of the lateral part. The invention also comprises embodiments in which the first portion of the lateral part in the lateral direction protrudes further outward than the reinforcement part. It is also possible that the external side of the reinforcement part terminates so as to be flush with the internal side of the first portion. This opens up the possibility for an overlap on the internal side of the reinforcement part.

The lateral part can be designed such that said lateral part comprises an upper peripheral portion which is contiguous to the upper chord and a lower peripheral portion which is contiguous to the lower chord. The reinforcement part can be of such a dimension that said reinforcement part is connected by way of a butt joint to the transition portion between the central portion and the upper peripheral portion, as well as to the transition portion between the central portion and the lower peripheral portion. Additionally, the reinforcement part can be connected to the upper peripheral portion as well is to the lower peripheral portion by way of a butt joint. The reinforcement part can be connected to the central portion in an overlapping manner. The directional indications up and down relate to the state of the boom-arm segment shown in the drawings, and do not imply any limitation in terms of the later assembled position of the boom-arm segment. Assembled positions which are rotated by 90° or by 180° in relation to the state shown in the figures are in particular possible.

An upper end of the reinforcement part can terminate in the upper peripheral portion so that the reinforcement part does not protrude upward beyond the contour defined by the upper chord. A lower end of the reinforcement part can protrude beyond the lower peripheral portion. This is particularly expedient when the reinforcement part forms a joint receptacle of the boom-arm segment by way of which the boom-arm segment is connected to an adjacent boom-arm segment or to a base of the boom arm. The reinforcement part can comprise a receptacle for a link pin. The link pin can be disposed in a position below the lower chord.

The lateral offset between the first portion and the second portion of the lateral part can be generated in that the lateral part is edge-bent multiple times. The lateral part can be edge-bent in one direction between the first portion and the transition portion. The lateral part can be edge-bent in the opposite direction between the transition portion and the second portion. The bend angle of the two edges can be chosen such that the first portion of the lateral part lies in a plane which is parallel to the second portion of the lateral part. The transition portion can extend in a plane which intersects the plane of the first lateral part at an angle between 10° and 80°, preferably at an angle between 15° and 30°. If the lateral part has an upper peripheral portion and a lower peripheral portion, the transition between the central portion and the upper peripheral portion as well as the transition between the central portion and the lower peripheral portion can be formed by two such combinations of edges.

The first portion, the transition portion, and the second portion of the lateral part can be elements of a shell component in which the shell component comprises an areal portion of the upper chord or of the lower chord. The shell component can be composed of a metal sheet which is edge-bent between the areal portion of the upper chord or lower chord and the peripheral portion of the lateral part. A peripheral region of the upper chord or lower chord, and the peripheral portion of the lateral part, can enclose an angle between 70° and 100°, preferably an angle between 80° and 90°.

The boom-arm segment can comprise a box section with an upper chord, a lower chord, and two lateral parts disposed between the upper chord and the lower chord. The box section can be assembled from half-shells. A first half-shell can comprise the upper chord and in each case one upper peripheral portion and in each case one upper transition portion of the mutually opposite lateral parts. A second-half-shell can comprise the lower chord and in each case one lower peripheral portion and in each case one lower transition portion of the mutually opposite lateral parts. Each of the lateral parts can be provided with a bent edge so that the central portions have a lateral offset relative to the peripheral portions. The bent edge can be designed such that the spacing between the central portions of the mutually opposite lateral parts is smaller than the spacing between the peripheral portions of the mutually opposite lateral parts.

The upper chord and/or the lower chord can be embodied as planar metal sheets. In order for the stability of the boom-arm segment to be further increased, a plurality of edges aligned in the longitudinal direction can also be incorporated in the upper chord and/or the lower chord. The edges can all be curved in the same direction so that the upper chord/lower chord form a curved profile in the cross section. Edges which are bent in mutually opposite directions are also possible, so that one or a plurality of corrugations are formed in the upper chord and/or lower chord.

The lateral parts of the box-shaped profile can be disposed in a plane parallel to gravity. In the box-shaped profile, when viewed in a section perpendicular to the longitudinal axis of the boom-arm segment, the lateral parts can be aligned so as to be mutually parallel, and/or the chord faces can be aligned so as to be mutually parallel.

In particular when the box section is assembled from two half-shells, or else when there is another number of partial profiles distributed across the circumference of the box section, it can be provided that a connection between two profile parts, which is disposed within the lateral part, is generated. In one embodiment, the connection is not disposed in one of the peripheral portions of the lateral part but in a bent-edge central portion of the lateral part that lies opposite the peripheral portion.

The connection between a first profile part and a second profile part of the box section, which connection is disposed within the lateral part, can be configured as a butt joint or overlapping. The connection can be produced by a weld seam which from one of the participating profile parts extends along the end edge. The end edge of the other profile part can be edge-bent in relation to the central portion so that the end edge acts as an additional buckling strength. The buckling strength can be aligned inward in terms of the box section.

The reinforcement part can comprise an end region which runs out within the lateral part. The end region can run out in the form of a taper in the lateral part. The end region can overlap the lateral part. The tip of the end region can run out in the central portion of the lateral part. The outermost point of the end region is referred to as the tip, irrespective of whether the end region tapers to a sharp point or has another shape, for example is radiused. The tip of the end region can have a position which is spaced apart from a welded connection by way of which the profile parts of the box section are connected. In particular, the tip of the end region can be disposed close to the neutral axis of the boom-arm segment, which means that the spacing between the tip of the end region and the nearest chord is greater than the spacing between the tip and the neutral axis at least by a factor of 2, preferably a factor of 3, furthermore preferably by a factor of 5. The end region can be connected to the lateral part by way of an encircling welded connection. In order to avoid stress peaks, the weld seam can extend beyond the end of the end region, into the lateral part. A further measure for avoiding stress peaks can lie in that the reinforcement part is machined, for example by milling, such that the material thickness of the reinforcement part is reduced in a region. This can apply in particular for a region in which the reinforcement part overlaps the lateral part. For the purpose of reducing weight, it is also possible to generate a reduced material thickness in such regions in which the reinforcement part is subject to lower loads.

The box section can taper from proximal to distal. The taper can relate to the vertical plane and/or the horizontal plane. The length across which the box section is tapered can correspond to at least 30%, preferably at least 50%, furthermore preferably at least 70%, of the length of the boom-arm segment. Proximal refers to an end of the boom-arm segment which in the unfolded state of the boom arm is closer to the base (thus closer to the truck, for example) on which the boom arm is suspended. Conversely, the distal end of the boom-arm segment in the unfolded state is closer to the free end of the boom arm.

The reinforcement part can form a proximal joint receptacle of the boom-arm segment. A receptacle for a link pin can be configured in the reinforcement part. An articulated lever to which a hydraulic cylinder can be connected may be connected to the reinforcement part. The hydraulic cylinder has the function of pivoting the boom-arm segment relative to an adjacent structure, in particular relative to an adjacent boom-arm segment. The articulated lever can be connected to the reinforcement part by way of a pivoting connection.

It is also possible that the reinforcement part is configured as a receptacle for a hydraulic cylinder. The reinforcement part can in particular form a receptacle for a link pin by way of which a hydraulic cylinder can be pivotably connected to the reinforcement part.

In one embodiment, the boom-arm segment comprises a first reinforcement part which is configured as a joint receptacle, and a second reinforcement part which is designed as a receptacle for a hydraulic cylinder. Both reinforcement parts can have the features mentioned and be connected to the lateral parts in the way mentioned. The joint receptacle can form an end of the boom-arm segment. The receptacle for the hydraulic cylinder can be disposed so as to be spaced apart from the ends of the boom-arm segment. The spacing between the receptacle and the nearest end of the boom arm can in particular correspond to at least 5%, preferably at least 10%, of the length of the boom-arm segment. The spacing between the first reinforcement part and the second reinforcement part can correspond to at least 10%, preferably at least 30%, of the length of the boom-arm segment.

The reinforcement part can extend across the width of the boom-arm segment and on both sides of the boom-arm segment be connected to one of the lateral parts in the way described. The reinforcement part can in particular be designed such that the latter on both sides does not protrude in the lateral direction beyond the upper peripheral portions of the lateral parts. It can be avoided in this way that the boom-arm segment is imparted an increase in terms of the width on account of the reinforcement part. The reinforcement part can be, for example, a bent-edge metal sheet. It is also possible that the reinforcement part is produced in another way, for example as a casting, as a forging, or by 3D-printing. The lateral part can be composed of a metal sheet.

The boom-arm segment can comprise a fastening receptacle for a holder of a conveying line. The fastening receptacle can extend through the boom-arm segment in the transverse direction and form a transverse connection between the mutually opposite lateral parts of the boom-arm segment. For example, the fastening receptacle can be welded to each of the lateral parts. The fastening receptacle can extend between the central portions of the mutually opposite lateral parts. In this way, the fastening receptacle can offer additional protection against the lateral parts of the boom-arm segment deflecting laterally under load. As a result of the connection to the lateral parts, the forces exerted by the fastening elements can be positively introduced into the lateral parts.

The fastening receptacle can project in relation to the lateral part on one side of the boom-arm segment. On this side, the fastening receptacle can be designed such that a holder for the conveying line can be connected. For example, blind bores for a threaded connection may be provided. However, it is also possible that the holder is welded to the fastening receptacle, for example. In one embodiment, the boom-arm segment comprises a holder for a conveying line, which holder is connected to the fastening receptacle, and/or a conveying line which is fastened to the fastening receptacle. Moreover, hydraulic lines can be connected to the boom-arm segment, by way of which hydraulic lines hydraulic installations for folding up and unfolding the boom arm can be operated, for example.

The boom-arm segment can comprise a plurality of such fastening receptacles, in particular at least two fastening receptacles, preferably at least three fastening receptacles, furthermore preferably at least four fastening receptacles. The fastening receptacles can be distributed in a substantially uniform manner across the length of the boom-arm segment. One or a plurality of the fastening receptacles can be connected to a reinforcement part.

The invention moreover relates to a concrete-pump boom arm having a plurality of boom-arm segments, wherein at least one of the boom-arm segments is configured according to the invention. A pivot joint is in each case configured between two adjacent boom-arm segments. The axis of the pivot joint can be aligned such that said axis extends through the two lateral parts of the boom-arm segment, wherein the two lateral parts are preferably intersected perpendicularly, or conjointly with this direction enclose an angle of less than 10°, preferably less than 5°. The chord faces can extend parallel to the pivot axis.

The joint can comprise a first articulated lever which is pivotably mounted on a first boom-arm segment. The joint can comprise a second articulated lever which is pivotably mounted on the second boom-arm segment and which is moreover pivotably mounted on the first articulated lever. A hydraulic cylinder can extend from the first boom-arm segment to the first articulated lever so that a lifting movement of the hydraulic cylinder is converted to a pivoting movement between the boom-arm segments. The hydraulic cylinder, when viewed from the first boom-arm segment, is preferably mounted beyond the second articulated lever on the first articulated lever.

The concrete-pump boom arm can comprise a conveying line for a viscous material, in particular fresh concrete, which extends along the boom arm. Each segment of the boom arm can be assigned one segment of the conveying line. Adjacent segments of the conveying line can be connected to one another by way of a joint, wherein the joint axis is preferably coaxial with that joint by which the associated boom-arm segments are connected to one another. The individual segment of the conveying line can be configured as a rigid pipeline.

The invention moreover relates to a method for producing a boom-arm segment for a concrete pump, wherein the boom-arm segment comprises a lateral part which extends between an upper chord and a lower chord of the boom-arm segment. A bent edge is configured in the lateral part so that a first portion of the lateral part has a lateral offset relative to a second portion of the lateral part. A transition portion forms a connection between the first portion and the second portion. A reinforcement part, the material thickness of the latter bridging the lateral offset between the first portion and the second portion, and the transition portion are connected by way of a butt joint.

The method can be refined by further features which have been described in the context of the boom-arm segment according to the invention. The boom-arm segment can be refined by further features which have been described in the context of the method according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by way of example hereunder with reference to the appended drawings and by means of advantageous embodiments. In the figures:

FIG. 1 shows a concrete-pump vehicle having a boom arm in the folded-up state;

FIG. 2 shows the concrete-pump vehicle from FIG. 1 with the unfolded boom arm;

FIG. 3 shows a boom-arm segment according to the invention;

FIG. 4 shows a joint between two boom-arm segments;

FIG. 5 shows the proximal end of the boom-arm segment from FIG. 3 in an enlarged illustration;

FIG. 6 shows a fragment from the boom-arm segment from FIG. 3 in an enlarged illustration;

FIG. 7 shows the distal end of the boom-arm segment from FIG. 3 in an enlarged illustration;

FIG. 8 shows a fastening receptacle of the boom-arm segment from FIG. 3 in an enlarged illustration;

FIG. 9 shows the fastening receptacle from FIG. 8 in another perspective;

FIG. 10 shows the proximal end of the boom-arm segment from FIG. 5 in a perspective illustration;

FIG. 11 shows the distal end of the boom-arm segment from FIG. 7 in a perspective illustration; and

FIG. 12 shows a cross section along the line A-A in FIG. 5.

DETAILED DESCRIPTION

A motor truck 14 shown in FIG. 1 is equipped with a concrete pump 15 which conveys liquid concrete from a storage tank 16 through a conveying line 17. The conveying line 17 extends along a boom arm 18 which is rotatably mounted on a swing bearing 19. The boom arm 18 comprises three boom-arm segments 20, 21, 22 which are connected to one another in an articulated manner. In that the boom-arm segments 20, 21, 22 by way of the joints are pivoted relative to one another, the boom arm 18 can alternate between a folded-up state (FIG. 1) and an unfolded state (FIG. 2). The conveying line 17 extends beyond the distal end of the third boom-arm segment 22 so that the liquid concrete can be delivered in a region which is remote from the concrete pump 15.

Depending on the pivoted state of the boom arm, the loads act on the boom-arm segments 20, 21, 22 in very different directions. Moreover, the boom arm is subjected to a high dynamic load as a result of the pulsed conveying of the liquid concrete.

The pivot joints between the boom-arm segments 20, 21, 22 are designed such that the latter enable a large pivoting angle. In the folded-up state, the boom-arm segments 20, 21, 22 lie so as to be substantially mutually parallel and enclose therebetween a small angle. In the unfolded state according to FIG. 2, the boom-arm segments 20, 21, 22 extend approximately so as to be mutual extensions.

The articulated construction is illustrated in FIG. 4, using an example of the pivot joint between the first boom-arm segment 20 and the second boom-arm segment 21. The joint axis is formed by a link pin 23 by way of which a proximal end of the boom-arm segment 21 is connected to a distal end of the boom-arm segment 20. A first articulated lever 24 is mounted on the first boom-arm segment 20 so as to be adjacent to the link pin 23. A second articulated lever 25 is mounted on the second boom-arm segment 21 so as to be adjacent to the link pin 23. The two articulated levers are connected in an articulated manner to one another at 26. A hydraulic cylinder 27 extends from a receptacle 28 on the first boom-arm segment 20 to the outer end of the first articulated lever 24. A lifting movement of the hydraulic cylinder 27 is converted to a pivoting movement between the boom-arm segments 20, 21 by way of the articulated levers 24, 25.

A boom-arm segment 30 according to the invention, shown in FIG. 3, extends from a proximal end 31 to a distal end 32. The boom-arm segment 30 is configured as a box-shaped profile with an upper chord 33, a lower chord 34, and two lateral parts 35, 36. The box-shaped profile of the boom-arm segment tapers continuously from the proximal end 31 to the receptacle 28 for the hydraulic cylinder. In this way, the two lateral parts 35, 36, and the upper chord 33 and the lower chord 34, thus converge in each case as the spacing from the proximal end 31 increases.

Close to the proximal end 31, the boom-arm segment 30 is reinforced by a first reinforcement part 40 which forms a proximal joint receptacle 57 of the boom-arm segment 30. Proceeding from the first reinforcement part 40, the box-shaped profile extends in the direction of the distal end 32. The box-shaped profile is assembled from an upper half-shell 41 and a lower half-shell 47 which are in each case configured as bent-edge panels.

According to the cross-sectional illustration in FIG. 12, the two lateral parts 35, 36 comprise in each case one upper peripheral portion 42 which is contiguous to the upper chord 33, and a lower peripheral portion 43 which is contiguous to the lower chord 34. The upper peripheral portion 42 and the lower peripheral portion 43 lie in the same plane. A central portion 44 which has a lateral offset 56 relative to the peripheral portions 42, 43 is disposed between the peripheral portions 42, 43. The lateral parts 35, 36 are bent inward so that the central portions 44 of the two lateral parts 35, 36 have a smaller mutual spacing than the peripheral portions 42, 43 of the lateral parts 35, 36. Transition portions 45, 46 are configured between the central portion 44 and the peripheral portions 42, 43, said transition portions 45, 46 conjointly with the plane of the peripheral portions 42, 43, or the plane of the central portions 44, which is parallel thereto, enclosing in each case an angle of approximately 30°.

The upper half-shell 41 comprises the upper chord, the upper peripheral portions 42, the upper transition portions 45, and the upper part of the central portions 44 of in each case both lateral parts 35, 36. The lower half-shell 47 comprises the lower chord 34, the lower peripheral portions 33, the lower transition portions 46, and the lower part of the central portion 44 of in each case both lateral parts 35, 36. The upper end of the lower half-shell 47 overlaps the lower end of the upper half-shell 41. Configured on the lower end of the upper half-shell 47 is a weld seam by which the two half-shells 41, 47 are connected to one another. The lower half-shell 47 by way of the end edge 55 thereof is edge-bent inward and in this way forms a buckling strength for the box section.

The first reinforcement part 40 has a greater material thickness than the box section made from the half-shells 41, 47, cf. FIG. 12. The external side of the first reinforcement part 40 coincides with the external side of the upper peripheral portions 42. The internal side of the first reinforcement part 40 coincides with the external side of the central portions 44. The box section by way of the transition portions 45, 46 alternates between the external side and the internal side of the first reinforcement part 40.

The transition portions 45, 46 and the peripheral portions 42, 44 are welded to the first reinforcement part 40 by way of a butt joint. The central portions 44 overlap the first reinforcement part 40. The connection between the first reinforcement part 40 and the central portions 44 is formed by an encircling weld seam about the first reinforcement part 40.

A straight line which extends in the longitudinal of the lateral part in FIG. 12 is substantially perpendicular to the drawing plane. In the region of an upper peripheral portion 42, where the connection to the reinforcement part 40 is configured as a butt joint, a straight line which extends in the interior of the upper peripheral portion 42, in the region of the butt joint intersects an end face of the upper peripheral portion 42 and an end face of the reinforcement part 40. It likewise applies in the region of the transition portions 45, 46, and in the region of the lower peripheral portions 43, that such a straight line intersects the corresponding end faces. In contrast thereto, the connection to the central portions 44 is configured in an overlapping manner so that the internal side of the reinforcement part 40 is flush with the external side of the central portions 44. A straight line which within the central portion 44 extends in the longitudinal direction, does not intersect the end face of the reinforcement part 40 but extends at a spacing from the internal side of the reinforcement part 40.

A joint bore 37 is configured in the first reinforcement part 40 according to FIGS. 5, 10. The joint bore receives the link pin 23, the latter connecting the boom-arm segment 30 to an adjacent boom-arm segment. Disposed next to the joint bore 37 is a stud bolt 38 to which the articulated lever 25 is connected. Accordingly, the boom-arm segment 30 close to the distal end thereof comprises a further joint bore 37 and a further stud bolt 38 to which an articulated lever 24 can be connected.

The boom-arm segment 30 comprises a second reinforcement part 50 which forms the receptacle 28 for the hydraulic cylinder. The second reinforcement part 50 has the same material thickness as the first reinforcement part 40 and is incorporated in the contour of the upper half-shell 41 in the same way. The second reinforcement part 50 thus overlaps the central portions 44 of the lateral parts 35, 36 and on the latter is connected to the upper half-shell 41 by an encircling weld seam. The upper transition portion 45 and the upper peripheral portion 42 are welded to the second reinforcement part 50 by way of a butt joint.

The distal joint receptacle 51 which is shown in FIGS. 7 and 11 comprises a reinforcement sheet 52 which is added on top of the sheet of the box section. The connection between the reinforcement sheet 52 and the box section is formed by an encircling weld seam which extends across the circumference of the reinforcement sheet 52. The joint receptacle 51 comprises a joint bore 37 which receives the link pin 23 for the connection to an adjacent boom-arm segment. Disposed next to the joint bore 37 is a stud bolt 38 to which the articulated lever 25 is connected.

The boom-arm segment according to FIG. 3 comprises a plurality of fastening receptacles 53 for attaching holders (not illustrated) for the conveying line 17. A first fastening receptacle 53 is connected to the first reinforcement part 40. Two further fastening receptacles 53 are disposed in the lateral parts 35, 36 of the box section. A fourth fastening receptacle 53 is disposed close to the distal joint receptacle 51.

According to FIGS. 8 and 9, the fastening receptacle 53 forms a transverse connection 54 between the first lateral part 35 and the second lateral part 36. The transverse connection 54 is formed by a tubular piece which is welded to the central portions 44 of both lateral parts 35, 36. In that the lateral parts 35, 36 are held at a fixed mutual spacing by the tubular piece 54, the fastening receptacles 53 counteract any buckling deformation of the boom-arm segment 30.

The tubular piece 54 on the side of the first lateral part 35 terminates as a tubular stub which slightly projects in relation to the central portion 44 of the lateral part 35. On the side of the second lateral part 36, the fastening receptacle 53 is provided with four threaded bores to which the holder for the conveying line can be fixedly screwed.

Claims

1. A boom-arm segment for a concrete pump, wherein the boom-arm segment (30) comprises a lateral part (35, 36) which extends between an upper chord (33) and a lower chord (34) of the boom-arm segment (30), and wherein configured in the lateral part (35, 36) is a bent edge so that a first portion (42, 43) of the lateral part (35, 36) has a lateral offset (56) relative to a second portion (44) of the lateral part (35, 36), and having a transition portion (45, 46) which forms a connection between the first portion (42, 43) and the second portion (44), wherein the boom-arm segment (30) has a reinforcement part (40, 50) with a material thickness bridging the lateral offset (56) between the first portion (42, 43) and the second portion (44), and wherein the reinforcement part (40, 50) and the transition portion (45, 46) are connected by a butt joint so that an end face of the transition portion (45, 46) bears on an end face of the reinforcement part (40, 50), and the reinforcement part (40, 50) adjoins the transition portion (45, 46) in a longitudinal direction.

2. The boom-arm segment of claim 1, wherein the connection between the reinforcement part (40, 50) and the lateral part (35, 36) is a welded connection.

3. The boom-arm segment of claim 1, wherein the reinforcement part (40, 50) and the first portion (42, 43) of the lateral part (35, 36) are connected by a butt joint.

4. The boom-arm segment of claim 1, wherein the reinforcement part (40, 50) overlaps the second portion (44) of the lateral part (35, 36).

5. The boom-arm segment of claim 4, wherein the reinforcement part (40, 50) is connected to the second portion (44) of the lateral part (35, 36) by a weld seam which extends along a portion of an encircling edge (58) of the reinforcement part (40, 50).

6. The boom-arm segment of claim 1, wherein the first portion (42, 43) forms a peripheral portion of the lateral part (35, 36), which peripheral portion is contiguous to the upper chord (33) or the lower chord (34) of the lateral part (35, 36).

7. The boom-arm segment of claim 1, wherein the second portion (44) forms a central portion of the lateral part (35, 36), which central portion is spaced apart from the upper chord (33) and the lower chord (34).

8. The boom-arm segment of claim 1, wherein the first portion (42, 43) of the lateral part (35, 36) comprises an upper peripheral portion (42) and a lower peripheral portion (43), and in that the reinforcement part (40, 50) is welded to the upper peripheral portion (42) and to the lower peripheral portion (43).

9. The boom-arm segment of claim 1, wherein the first portion (42, 43), the transition portion (45, 46), and the second portion (44) of the lateral part are elements of a shell component (41, 47) in which the shell component (41, 47) comprises an areal portion of the upper chord (33) or of the lower chord (34).

10. The boom-arm segment of claim 1, wherein the boom-arm segment (30) comprises a box section with an upper chord (33), a lower chord (34), and two lateral parts (35, 36) disposed between the upper chord (33) and the lower chord (34), and in that the box section is assembled from half-shells (41, 47), wherein a first half-shell (41) comprises the upper chord (33) and in each case one upper peripheral portion (42) and in each case one upper transition portion (45) of the mutually opposite lateral parts (35, 36), and wherein a second half-shell (47) comprises the lower chord (34) and in each case one lower peripheral portion (43) and in each case one lower transition portion (46) of the mutually opposite lateral parts (36).

11. The boom-arm segment of claim 10, wherein the first half-shell (41) and the second half-shell (47) are connected to one another in the central portion of the lateral part.

12. The boom-arm segment of claim 10, wherein an end edge (55) of the second half-shell (47) is edge-bent in relation to the central portion (44) to form a buckling strength for the box section.

13. The boom-arm segment of claim 10, comprising a fastening receptacle (53) for a holder of a conveying line (17), wherein the fastening receptacle forms a transverse connection (54) between the mutually opposite lateral parts (35, 36) of the boom-arm segment (30).

14. The boom-arm segment of claim 1, comprising a first reinforcement part (40) which is configured as a joint receptacle (57), and by a second reinforcement part (50) which is designed as a receptacle (28) for a hydraulic cylinder.

15. A method for producing a boom-arm segment for a concrete pump, wherein the boom-arm segment (30) comprises a lateral part (35, 36) which extends between an upper chord (33) and a lower chord (34) of the boom-arm segment (30), said method comprising:

configuring in the lateral part (35, 36) to include a bent edge so that a first portion (42, 43) of the lateral part (35, 36) has a lateral offset (56) relative to a second portion (44) of the lateral part (35, 36), and a transition portion (45, 46) which forms a connection between the first portion (42, 43) and the second portion (44);

selecting a material thickness of a reinforcement part (40, 50) to bridge the lateral offset (56) between the first portion (42, 43) and the second portion (44); and

connecting the reinforcement part (40, 50) to the transition portion (45, 46) by way of a butt joint so that an end face of the transition portion (45, 46) bears on an end face of the reinforcement part (40, 50), and the reinforcement part (40, 50) adjoins the transition portion (45, 46) in a longitudinal direction.