Patent Application
20240344344
The invention relates to a boom arm segment for a concrete pump and to a method for producing a boom arm segment.
A concrete pump boom arm can be used to guide a concrete pump delivery line in such a way that the liquid concrete delivered by the concrete pump is applied in a region remote from the concrete pump. A concrete pump boom arm is usually composed of a plurality of boom arm segments, wherein, in an unfolded state, the boom arm segments in their total make up the length of the boom arm, and wherein, in folded-up state, the boom arm segments are folded together into a compact state to facilitate transport.
Concrete pumps usually deliver the liquid concrete in pulses, and therefore the boom arms are subject to significant dynamic loads. In addition, the boom arm segments can be folded differently depending on at which distance from the concrete pump the liquid concrete is to be applied when the concrete pump is in operation. This leads to the tensile and compressive loads on a boom arm segment acting in very different directions depending on the operating state of the boom arm. For these reasons, boom arm segments of a concrete pump are subject to special loads during operation.
The invention is based on the object of presenting a concrete pump boom arm segment which has a low weight and is cost-effective to produce. Proceeding from the above-mentioned prior art, the object is achieved with the features of the independent claims. Advantageous embodiments are specified in the dependent claims.
The boom arm segment according to the invention comprises an upper flange, a lower flange and two side parts connecting the upper flange and the lower flange. The side parts each comprise a lower edge portion adjacent to the lower flange and a central portion arranged between the lower edge portion and the upper flange, wherein the distance between the central portion of the first side part and the central portion of the second side part is greater than the distance between the lower edge portion of the first side part and the lower edge portion of the second side part. The boom arm segment comprises a joint connection with a joint surface, which defines a pivot axis for a pivot connection between the boom arm segment and an adjacent structure. The joint surface is at least partially arranged below the plane of the lower flange. The joint connection is connected via a first connecting carrier to the central portion of the first side part, wherein the first connecting carrier extends beyond the lower edge portion of the first side part without being connected to the lower edge portion of the first side part.
The invention has recognized that, with the first connecting carrier, a particularly favorable possibility is created of introducing the forces acting in the region of the joint connection into the boom arm segment. To avoid stress peaks between the connecting carrier and the side part, the first connecting carrier is guided beyond the edge portion of the first side part without being connected to the edge portion of the first side part.
The central portion of the first side part may extend in a plane which encloses a right angle with a pivot axis defined by the joint connection. A longitudinal center plane is a plane which is parallel thereto and intersects the joint connector in the middle. The central portion of the first side part may be at the same distance from the longitudinal center plane as the central portion of the second side part. The lower edge portion of the first side part may be at the same distance from the longitudinal center plane as the lower edge portion of the second side part. The distance between the lower edge portion and the longitudinal center plane may be smaller than the distance between the central portion and the longitudinal center plane.
The first connecting carrier may extend in a plane parallel to the longitudinal center plane, and the distance between the first connecting carrier and the longitudinal center plane may be greater than the distance between the outer side of the central portion and the longitudinal center plane. In one embodiment, the inner side of the first connecting carrier lies in the same plane as the outer side of the central portion, and the first connecting carrier may rest on the outer side of the central portion. A first portion of the first connecting carrier may form a doubled-over portion with the central portion of the first side part. A second portion of the first connecting carrier may protrude from the central portion of the first side part in the direction of the joint connection. The boom arm segment may be designed in such a way that the second portion of the first connecting carrier, apart the connections to the first portion of the first connecting carrier and to the joint connection, has no further connections to components of the boom arm segment.
The first connecting carrier may be connected to the central portion of the first side part by welding. A weld may be formed which extends along a circumferential line formed by the first connecting carrier resting on the central portion of the first side part. In one embodiment, the weld extends without interruption over the entire length of the circumferential line.
The production of an uninterrupted weld over the entire length of the circumferential line is made more difficult if a portion of the circumferential line is enclosed between the projecting portion of the first connecting carrier and the lower edge portion. This region is accessible only with difficulty for welding machines. In order to facilitate the production of the weld, the first connecting carrier may be assembled from a first component and a second component. The first component may be designed such that it rests over its entire circumference on the central portion of the first side part. The entire circumference of the first component is then easily accessible for a welding machine.
After the first component of the first connecting carrier is welded to the central portion, the second component of the first connecting carrier can be welded to the first component. The weld between the first component and the second component may extend along a lower edge of the central portion of the first side part.
In addition or alternatively, the first connecting carrier may be connected to the central portion of the first side part by a welded connection arranged in the surface of the first connecting carrier. For this purpose, the first connecting carrier may have an aperture in which the welded connection is placed. The aperture can be filled with material by means of the welding process. The aperture may have a first portion extending in the longitudinal direction of the boom arm segment. The aperture may have a second portion enclosing an angle with the first portion. The angle may be between 60° and 80°. The aperture may be arranged adjacent to the proximal end of the first connecting carrier.
The first connecting carrier may comprise an end region which tapers off within the central portion of the first side part. The end region can form a distal end of the first connecting carrier. The end region may taper off as a tapered portion toward a tip of the end region. A tip refers to the outermost point of the end region, regardless of whether the end region converges there to a point or has a different shape, for example is rounded. The tip of the end region may have a position that is spaced from the upper and lower edges of the central portion. In particular, the tip of the end region may be arranged in the vicinity of the neutral fibers of the boom arm segment, which means that the distance between the tip of the end region and the nearest flange is greater at least by a factor of 2, preferably by a factor of 3, further preferably by a factor of 5, than the distance between the tip and the neutral fibers. The end region may be connected to the central portion of the first side part by a peripheral welded connection. To avoid stress peaks, the weld may extend beyond the end of the end region into the side part. Another measure for avoiding stress peaks may be to process the connecting carrier, for example by milling, in such a way that the material thickness of the connecting carrier is reduced toward the tip of the end region. For the purpose of reducing weight, it is also possible to produce a reduced material thickness in those regions in which the connecting carrier is less loaded.
The central portion of the first side part may extend as far as the upper flange. Alternatively, an upper edge portion may be formed between the central portion of the first side part and the upper flange, said upper edge portion having a lateral offset relative to the central portion. A transition portion may be formed between the central portion and the upper edge portion. The distance between the upper edge portion and the longitudinal center plane may be smaller than the distance between the central portion and the longitudinal center plane.
The lateral offset between the central portion and the upper edge portion may be produced by folding the side part several times. Between the central portion and the transition portion, the side part may be folded in one direction. Between the transition portion and the upper edge portion, the side part may be folded in the opposite direction. The bending angle of the two edges may be selected in such a way that the central portion of the side part lies in a plane which is parallel to the upper edge portion. The transition portion may extend in a plane that intersects the plane of the first side part at an angle of between 10° and 80°, preferably at an angle of between 15° and 30°. If the side part has an upper edge portion and a lower edge portion, the transition between the central portion and the upper edge portion and the transition between the central portion and the lower edge portion may be formed by two such edge combinations.
The boom arm may comprise a second connecting carrier, wherein the joint connection is connected via the second connecting carrier to the central portion of the second side part. The second connecting carrier may extend beyond the lower edge portion of the second side part without being connected to the lower edge portion of the second side part. The second connecting carrier may have the same features which are described within the context of the first connecting carrier. The second side part may have the same features which are described within the context of the first side part.
The upper flange, the lower flange and the side parts of the boom arm segment may form a box profile. The box profile may be assembled from shell components which are connected to one another by welds running in the longitudinal direction of the boom arm segment. A weld between a first shell component and a second shell component may extend along an edge of the central portion of the first side part. The weld may furthermore coincide with a weld between the first connecting carrier and the central portion of the first side part. A corresponding combination of welds may be provided between the second side part and the second connecting carrier.
In one embodiment, the box profile is assembled from two half shells, wherein a first half shell comprises the upper flange and in each case an upper partial portion of the opposite side parts. A second half shell may comprise the lower flange and in each case a lower partial portion of the opposite side parts. The two half shells may be welded together to form a box profile by means of two longitudinal welds.
The joint connection may be designed in such a way that forces acting on the joint connection from the outside are introduced exclusively via the two connecting carriers into the box profile, which is formed from the flanges and the side parts, of the boom arm segment. The boom arm segment may be designed in such a way that the joint connection, apart from the connection via the connecting carriers, does not have any connection to the lower flange and to the side parts of the boom arm segment. The joint connection may be spaced from the lower flange. A clearance may be provided between the joint connection and the lower flange. Toward the sides, the clearance may be delimited by the first connecting carrier and the second connecting carrier.
The details of top and bottom refer to the state of the boom arm segment that is shown in the drawings. The plane of the lower flange is defined by the longitudinal direction and the transverse direction of the lower flange. In the case of a lower flange that does not extend in the same plane over its entire length, the detail refers to that portion of the lower flange which is adjacent to the joint connection. The directional details are based on the assumption that the plane of the lower flange is oriented horizontally. This means no restriction with regard to the subsequent mounting position of the boom arm segment; in particular, mounting positions which are rotated by 90° or by 180° compared to the state shown in the figures are possible.
The lower flange may extend along a straight line in the direction of an opposite end of the boom arm segment (longitudinal direction), starting from an end adjacent to the joint connection. That end of the boom arm segment which is adjacent to the joint connection may be the proximal end. The plane of the lower flange is defined by the longitudinal direction of the lower flange and the dimension parallel to the pivot axis of the joint connection. If the lower flange does not extend in one plane over the entire length of the boom arm, the plane of the lower flange is defined by a portion of the lower flange adjacent to the joint connection. The joint connection may be arranged below the plane of the lower flange.
It is possible for the lower flange to also extend in the transverse direction in the plane of the lower flange. Embodiments in which the lower flange in the transverse direction has a shape protruding out of the plane of the lower flange are preferred. For this purpose, the lower flange may have one or more bends or one or more folds. The direction of the edges/bends may be parallel to the longitudinal direction of the boom arm segment such that a shape protruding out of the plane is produced in the transverse direction. The lower flange may have a shape curved in the transverse direction, for example by beveling of the lower flange in such a way that the sum of the beveled portions corresponds to a curvature. The curvature may be oriented in such a way that the distance between the pivot axis of the pivot connection and a central region of the lower flange is smaller than the distance between the pivot axis and a peripheral region of the lower flange. The plane of the lower flange is defined by that region of the lower flange which is at the smallest distance from the joint connection. As an alternative to a curved shape, edges that are bent in mutually opposite directions are also possible, and therefore one or more beads are formed in the lower flange. In particular in the case of a lower flange that is not flat in the transverse direction, it is advantageous if said lower flange is straight in the longitudinal direction, i.e. does not protrude out of the plane of the lower flange in the longitudinal direction.
The boom arm segment is designed to be connected to an adjacent structure via a pivot joint. The adjacent structure may be another segment of the boom arm or a base frame of the concrete pump. The pivot joint is formed by a first joint connection, which is an element of the boom arm segment, and by a second joint connection, which is an element of the adjacent structure separate from the boom arm segment. The position of the pivot axis is defined by the joint connection of the boom arm segment. The joint connection may comprise a joint bore, with the axis of the joint bore corresponding to the pivot axis. The joint connection may comprise a structure within which the joint bore is formed. For example, the joint connection may be tubular section within which the joint bore extends. The joint connection may form a receptacle for a joint bolt. In this case, the receptacle for the joint bolt corresponds to the joint surface that defines the pivot axis.
By the joint surface of the joint connection defining the pivot axis being arranged at least partially below the lower flange, the possibility is included that the plane of the lower flange intersects the joint connection. In other words, the joint surface may comprise a region which coincides with the plane of the lower flange or lies above the plane of the lower flange. This design can be associated with the fact that the lower flange ends at a distance from the joint connection, and the joint connection is thus arranged in an extension of the lower flange.
In a development, the boom arm segment is designed in such a way that the pivot axis defined by the joint surface is arranged below the lower flange. It is further advantageous if the joint surface defining the pivot axis is arranged in its entirety below the lower flange. Further preferably, the distance between the pivot axis of the joint connection and the plane of the lower flange may be of such a size that the plane of the lower flange does not intersect the structure of the joint connection.
The joint connection may form a proximal joint receptacle of the boom arm segment. A receptacle for an articulated lever, to which a hydraulic cylinder may be connected, may be formed in the connecting carrier. The function of the hydraulic cylinder is to pivot the boom arm segment relative to an adjacent structure, in particular relative to an adjacent boom arm segment. The articulated lever may be connected to the connecting carrier via a pivot connection.
The boom arm segment may comprise a fastening receptacle for a holder of a delivery line. The fastening receptacle may extend in a transverse direction through the boom arm segment and form a transverse connection between the opposite side parts of the boom arm segment. For example, the fastening receptacle may be welded to each of the side parts. The fastening receptacle may extend between the central portions of the opposite side parts. The fastening receptacle may thus provide additional protection against the side parts of the boom arm segment moving to the side under load. The connection with the side parts allows the forces exerted by the fastened elements to be readily introduced into the side parts.
On one side of the boom arm segment, the fastening receptacle may protrude from the side part. On this side, the fastening receptacle may be designed in such a way that a holder for the delivery line may be connected. For example, blind holes may be provided for a screw connection. However, it is also possible for the holder to be welded to the fastening receptacle, for example. In one embodiment, the boom arm segment comprises a holder, which is connected to the fastening receptacle, for a delivery line and/or a delivery line connected to the fastening receptacle. In addition, hydraulic lines may be connected to the boom arm segment, via which lines, for example, hydraulic devices for folding up and unfolding the boom arm may be operated.
The boom arm segment may comprise a plurality of such fastening receptacles, in particular at least two fastening receptacles, preferably at least three fastening receptacles, further preferably at least four fastening receptacles. The fastening receptacles may be substantially uniformly distributed over the length of the boom arm segment. One or more of the fastening receptacles may be connected to a connecting carrier.
The delivery line may extend over the length of the boom arm segment. For connection to a delivery line of an adjacent boom arm segment, the delivery line at one or both of its ends may comprise a joint part which is designed to form a pivotable connection to a delivery line of an adjacent boom arm segment. The pivot axis defined by the joint part may be coaxial to the pivot axis of the joint connection and thus coaxial to the axis of the boom arm pivot joint. The delivery line may be arranged to the side of the boom arm segment. This is an essential boundary condition for the design of boom arm segments because, on the one hand, it has to be possible to bring the boom arm segments of a boom arm into a folded up state despite the delivery line being arranged parallel, and because, on the other hand, there is not as much space available in the lateral direction as desired without exceeding the permissible width of road-approved vehicles.
The invention also relates to a concrete pump boom arm having a plurality of boom arm segments, wherein at least one of the boom arm segments is designed according to the invention. A pivot joint is formed between in each case two adjacent boom arm segments. The axis of the pivot joint may be oriented in such a way that it extends through the planes of the two side parts of the boom arm segment, with the two planes preferably being intersected at a right angle or enclosing an angle of less than 10°, preferably less than 5°, with this direction. The flange surfaces may extend parallel to the pivot axis.
The joint may comprise a first articulated lever, which is pivotably attached to a first boom arm segment. The joint may comprise a second articulated lever, which is pivotably attached to the second boom arm segment and which is also pivotably attached to the first articulated lever. A hydraulic cylinder may extend from the first boom arm segment to the first articulated lever, and therefore a lifting movement of the hydraulic cylinder is translated into a pivoting movement between the boom arm segments. As seen from the first boom arm segment, the hydraulic cylinder is preferably attached to the first articulated lever on the other side of the second articulated lever.
The concrete pump boom arm may comprise a delivery line for a thick material, especially fresh concrete, said delivery line extending along the boom arm. Each segment of the boom arm may be assigned a segment of the delivery line. Adjacent segments of the delivery line may be connected to each other via a joint, wherein the joint axis is preferably coaxial to the joint by which the associated boom arm segments are connected to each other. The individual segment of the delivery line may be designed as a rigid pipe.
The invention also relates to a method for producing such a boom arm segment, in which a first component of the first connecting carrier is welded to the central portion of the first side part, and in which a second component of the first connecting carrier is welded to the first component.
The method may be developed with further features that are described in connection with the boom arm segment according to the invention. The boom arm segment may be developed with further features that are described in connection with the method according to the invention.
The invention will be described by way of example below on the basis of advantageous embodiments by reference to the accompanying drawings. In the drawings:
A truck 14 shown in
Depending on the pivoted state of the boom arm, the loads act on the boom arm segments 20, 21, 22 in entirely different directions. In addition, the boom arm is subject to a high dynamic load due to the delivery of liquid concrete in pulses.
The pivot joints between the boom arm segments 20, 21, 22 are designed so as to permit a large pivot angle. In the folded up state, the boom arm segments 20, 21, 22 lie substantially parallel to one another and enclose a small angle between them. In the unfolded state according to
The joint construction is shown in
A boom arm segment 30 according to the invention shown in
In the vicinity of the proximal end 31, the boom arm segment 30 is provided with a first connecting carrier 40 and a second connecting carrier 57, which form a connection between the box profile and a proximal joint receptacle 37 of the boom arm segment 30. Starting from the proximal end 31, the box-shaped profile extends toward the distal end 32. The box-shaped profile is assembled from an upper half shell 41 and a lower half shell 47, which are each in the form of folded metal sheets.
According to the cross-sectional illustration in
The upper half shell 41 comprises the upper flange 33 and the side parts 35, 36 as far as the lower end of the central portions 44. The lower half shell 47 comprises the lower flange 34, the lower edge portions 43, the lower transition portions 45 and an overlapping strip 48, which overlaps the lower end of the central portions 44, see
The two connecting carriers 40, 57 have a greater material thickness than the box profile consisting of the half shells 41, 47, see
The joint connection 37, which has the shape of a tubular section, in the interior of which a joint bore for receiving a joint bolt is formed, is welded between the connecting carriers 40, 57. The inner surface of the tubular section forms a joint surface 12, by which the pivot axis 74 is defined, see
The joint bore receives the joint bolt 23, which connects the boom arm segment 30 to an adjacent boom arm segment. The articulated lever 25 can be connected next to the articulated bore 37. Accordingly, the boom arm segment 30, in the vicinity of its distal end, comprises a further joint connection 50 and a further stud bolt 66 to which an articulated lever 24 can be connected. Between the distal end 32 and the proximal end 31, a receptacle 28 is arranged to which a hydraulic cylinder for actuating an adjacent boom arm segment can be connected.
According to
In the alternative embodiment according to
According to
In order to produce such a boom arm segment, an upper half shell 41 of the box profile is provided, which comprises the upper flange 33, the two upper edge portions 42 and the two central portions 44. The lower end of the upper half shell 41 corresponds to the lower end of the central portions 44. A lower half shell 47 of the box profile comprises the lower flange 34, the lower edge portions 43, the transition portions 45 and two overlapping strips 48 adjacent to the transition portion 45. The half shells 41, 47 are assembled in such a manner that the overlapping strips 48 lie on the inner side of the central portions 44 and overlap the lower end of the central portions 44. A weld is placed at the lower end of the central portions 44, said weld extending over the length of the half shells 41, 47 and connecting the half shells 41, 47 to each other, see
The connecting carriers 40, 57 are attached in a two-step process. First of all, a first component 51 is placed from the outside as a doubled-over portion onto the central portion 44 of one of the side parts 35, 36. The first component 51, which is a metal sheet having a greater material thickness, is dimensioned in such a way that the entire circumferential line of the first component 51 lies within the surface of the central portion 44. The first component 51 is connected to the central portion 44 by a circumferential weld, which extends without interruption over the entire circumference of the first component 51. The lower edge of the first component 51 lies close to the lower end of the central portion 44, and therefore the weld 55 in this region substantially coincides with the lower end of the central portion 44, see
At the same time, a connection between the first component 51 and a second component 52 is established by the weld 55 at the lower edge of the first component 51. It is possible to create a single weld 55 that connects both the first component 51 to the central portion 44 and the first component 51 to the second component. Alternatively, this can be split into two welding operations. The second component 52 does not rest on the central portion 44, but rather extends freely downward starting from the weld 55. The second component 52 is connected to the joint connection 37. In addition, the second component 52 has no connection to the transition portion 45 or to the lower edge portion 43. The joint connection 37 also has no connection to the box profile except for the connection produced via the connecting carriers 40, 57.
In the embodiment according to
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 120 617.0 | Aug 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/071713 | 8/2/2022 | WO |
