Multi-shell grab and construction machine

Abstract

Multi-shell grab (10) comprising at least three double-acting plunger cylinders (12) each with a cylinder and a piston rod (16) slidably mounted therein, a head section (20) with a distributor through which the plunger cylinders (12) can be supplied with hydraulic oil, a bottom section (22) on which at least three grab shells (1) movable by the plunger cylinders (12) can be attached, wherein the plunger cylinders (12) are arranged between the head and bottom sections (20, 22), characterized in that the head and bottom sections (20, 22) are connected to each other by screws (24) running parallel to the plunger cylinders (12).

Description

[0001] The present invention relates to a multi-shell grab according to the preamble of claim 1 and to a construction machine with such a multi-shell grab.

[0002] Multi-shell grabs are known in various designs from the prior art and typically feature a drive based on pivoting several grab shells by means of one or more hydraulic piston-cylinder units or hydraulic cylinders. One possible design of such a drive is to pivotally connect the hydraulic cylinders to a support structure of the grab via their cylinder housings (hereinafter referred to simply as "cylinders") and to couple the piston rods to the associated grab shells, so that extending or retracting the piston rods causes the grab shells to pivot or open or close.

[0003] For some applications, it is necessary to use low-profile multi-shell grabs. Such multi-shell grabs are already known in the prior art. To achieve the reduced overall height, the differential cylinders are recessed into the grab arm, with each cylinder bolted to the upper part of the support structure and the grab arm mounted below. This arrangement has the disadvantage that the closing force is reduced when the grab closes, making it more difficult to pick up and hold the material being lifted. Another disadvantage is the open design of the grab arm, which allows material to penetrate and cause damage. Furthermore, the existing hydraulic oil supply and return lines are extremely vulnerable, as the permissible routing radii are usually not met. This leads to hose wear and increased maintenance.Due to space constraints, hydraulic lines are often installed with a small diameter, resulting in significant back pressure and consequently energy losses. Another disadvantage is the installation and removal of the hoses during initial installation or repair.

[0004] For multi-shell grabs of conventional design, another possibility, known, for example, from DE10 2006 004 856 A1, is to mount one or more double-acting plunger cylinders (also referred to as reciprocating piston cylinders) fixedly, i.e., not pivotably, on the grab. The piston rods of the plunger cylinders typically have bearing eyes that move linearly when the plunger cylinders are actuated, i.e., when appropriate pressure is applied, typically along the longitudinal axis of the grab drive. By coupling the bearing eyes of the piston rods to the associated grab shells, the grab shells can be pivoted.

[0005] The present invention is therefore based on the objective of further developing a multi-shell gripper of the aforementioned type in such a way that it consists of few parts in a low-profile design and is therefore easy and inexpensive to manufacture and is not prone to malfunctions in operation.

[0006] According to the invention, this problem is solved by a multi-shell grab with the features of claim 1 and a construction machine with the features of claim 11. Advantageous embodiments of the invention are described in the dependent claims and the following description.

[0007] Accordingly, a multi-shell grab is proposed with at least three double-acting plunger cylinders, each with a cylinder and a piston rod slidably mounted therein, a head section with a distributor through which the plunger cylinders can be supplied with hydraulic oil, and a bottom section on which at least three grab shells movable by the plunger cylinders can be attached, wherein the plunger cylinders are arranged between the head and bottom sections and wherein the head and bottom sections are connected to each other by screws running parallel to the plunger cylinders.

[0008] In one embodiment, the piston rods of the plunger cylinders each have a bearing eye through which the piston rods can be coupled to a gripper shell. The coupling between the piston rod and the gripper shell is effected in particular by a connecting rod, which is pivotably connected to both the bearing eye of the piston rod and the gripper shell.

[0009] According to the invention, the drive of the multi-shell gripper essentially consists of the head section and the base section and the plunger cylinders arranged between them, wherein the head and base sections are held together by screws running parallel to the plunger cylinders. Thus, the drive of the multi-shell gripper is very simple and easy to assemble.

[0010] The connecting rod, which links the plunger cylinder to the respective gripper shell, pivots the gripper shell in such a way that it initially generates a higher closing force for material handling when closing. This allows for a high closing force, particularly for flat or low-profile multi-shell grippers. Due to the enclosed design of the gripper shell and the arrangement of the plunger cylinders, optimal protection of the entire gripper system is ensured, unlike in the prior art.

[0011] In one embodiment, the plunger cylinders are provided for at their ends to be received in corresponding recesses in the respective head and base sections. This allows for simple and stable mounting of the plunger cylinders.

[0012] According to a particularly advantageous embodiment, the plunger cylinders are formed by the corresponding recesses in the respective head and base sections themselves, as an alternative to the aforementioned variant. The hydraulic oil supply can be provided in a particularly efficient manner in the head or base section. This enables a particularly compact design, allowing for the realization of a particularly low-profile multi-shell grab.

[0013] In a further embodiment, the head section and / or the base section are designed as a cast / fired part or a welded part. This allows for very simple and cost-effective manufacturing of these essential components of the drive for the multi-shell grab.

[0014] In another version, the piston rods each have a bearing eye, via which the piston rods can be coupled to a gripper shell by means of a connecting rod.

[0015] In a further embodiment, the plunger cylinders are each wholly or partially covered by a protective plate that covers a portion of the piston rod extending outside the cylinder. This portion is preferably located between two spaced-apart cylinder sections. Preferably, the protective plates are curved, particularly in a semi-shell shape, and extend along a portion of the cylinder's outer circumference. The protective plates shield the exposed sections of the piston rods from contamination and mechanical damage. The term "protective plate" is to be interpreted broadly here and should not be understood as requiring the protective plate to be made of metal. Rather, materials other than metal, such as plastic or composite materials, can also be used.

[0016] Preferably, the protective plates have an opening or a longitudinal slot through which bearing eyes connected to or formed on the piston rods protrude for coupling with the gripper shells. The protective plates preferably also cover areas of the cylinder parts.

[0017] In a further embodiment, the bottom section comprises a base plate on which bearing eyes for attaching gripper shells are preferably arranged.

[0018] In a further embodiment, the plunger cylinders are provided with hydraulic connections at their ends on the head section side for supplying hydraulic oil to the plunger cylinder pressure chambers. These pressure chambers are formed by hydraulic channels integrated into a distributor within the head section. The hydraulic channels in the distributor can extend radially or star-shaped from a central area to the individual cylinders, or branch out.

[0019] In a further embodiment, each cylinder of a plunger cylinder has a first and a second hydraulic connection, the first hydraulic connection being a connection to a pressure chamber immediately adjoining it at the top, and the second hydraulic connection being a connection to a pressure chamber located at the bottom of the piston rod on the other side. The second hydraulic connection and the pressure chamber at the bottom are connected to each other via a connecting pipe, which extends through a longitudinal bore in the piston rod, preferably coaxial with the central axis of the piston rod. The pressure chambers and piston rods, or the connections of the hydraulic connections to the respective pressure chambers, can be designed as disclosed in DE 20 2005 017 762 U1.

[0020] In another embodiment, a rotary drive with a hydraulic rotary feedthrough is provided, which connects to the head section, in particular to the distributor, and preferably has a bearing eye for attaching the drive to a construction machine, for example to the stick of a hydraulic excavator.

[0021] The present invention further relates to a construction machine, in particular a hydraulic excavator, with a multi-shell grab according to the invention. The same advantages and properties are evident as for the multi-shell grab according to the invention, which is why a repetitive description is omitted here.

[0022] In one embodiment, the construction machine includes a hydraulic system by which the plunger cylinders can be supplied with hydraulic oil via the drive distributor. The hydraulic system includes, in particular, a hydraulic source.

[0023] Further features, details and advantages of the invention will become apparent from the exemplary embodiments explained below with reference to the figures. The figures show: Fig. 1: a multi-shell gripper according to the invention in an open position according to an exemplary embodiment in a perspective view; Fig. 2: the multi-shell gripper according to the invention Fig. 1 in closed position in a perspective view; Fig. 3: a side view of the multi-shell gripper according to the invention Fig. 1; Fig. 4: A top view of the multi-shell gripper according to the invention. Fig. 1 and Fig. 5: a vertical partial section along line AA according to Fig. 4 by a drive according to the invention.

[0024] The Fig. Figure 1 shows an embodiment of the multi-shell grab 10 according to the invention in a perspective view, wherein this is a multi-shell grab 10 with five pivotable grab shells 1. The multi-shell grab, also referred to as a polyp grab, can be attached to the boom of a hydraulic excavator, which supplies it with hydraulic oil. Of course, other embodiments are also conceivable, for example a three-part embodiment. In the Fig. Figure 1 shows the multi-shell grab in the open position, while it is in the Fig. 2, which is also shown in perspective view, is depicted in a closed position.

[0025] The multi-shell gripper 10 according to the invention comprises five double-acting plunger cylinders 12, each assigned to one of the gripper shells 1 and coupled to each via a connecting rod 2. The plunger cylinders 12 are each divided into two parts and parallel to each other (in the Fig. 1 vertically). In the embodiment shown here, the plunger cylinders 12 are formed by corresponding recesses 13 in a base section 22 of the multi-shell grab 10 and a head section 20 of the multi-shell grab 10. They are arranged evenly spaced on an imaginary circular path around the vertical axis of rotation of the multi-shell grab 10 (see the top view according to [reference]). Fig. 4).

[0026] The base section 22 comprises a base plate 34 on which pairs of bearing eyes 36 are formed, to which the gripper shells 1 are each pivotally mounted about a horizontal axis, as shown in the Fig. Figure 5 shows the head section 20, which includes a distributor 40 containing several hydraulic channels 44 for supplying hydraulic oil from a construction machine (e.g., a hydraulic excavator) to the plunger cylinders 12 integrated in the recesses 13. A rotary drive 50 with a hydraulic rotary union (not shown) is connected to the top of the distributor 40, through which the hydraulic oil from the construction machine can be fed into the distributor 40 in a known manner. The rotary drive 50, which has a bearing eye (not shown) on its upper side for connecting the multi-shell grab 10 or grab to the construction machine, allows the grab to be rotated about a central (in the Fig. 5 vertical) axis of rotation.

[0027] The double plunger cylinders 12, also known as double-acting plunger cylinders, each comprise a cylinder and a piston rod 16 slidably mounted therein. The cylinders are divided into two sections, each comprising two cylinder parts 15 spaced axially apart (i.e., along the longitudinal axis of the multi-shell gripper 10). In the central region, i.e., in the area between the cylinder parts 15, the piston rod 16 extends freely, i.e., outside the cylinder. In the embodiment shown here, the spaced-apart cylinder parts 15 are formed by the recesses 13 in the bottom section 22 and the top section 20, respectively. This allows for a low-profile, very compact design.

[0028] The piston rods 16 each have an outwardly projecting bearing eye 18, to which the connecting rod 2 (or two parallel piston rods 2, as shown in the figures) of the associated gripper shell 1 is articulated to form a linear (in the Fig. 1. The vertical movement of the piston rod 16 is transferred to the gripper shell 1 and pivots it about the pivot point on the base plate 34. To allow free movement of the bearing eyes 18, the distances between the cylinder parts 15 are chosen such that the bearing eyes 18 always move freely, i.e., within the space between them. Alternatively, a one-piece cylinder with a corresponding longitudinal slot in the movement area of ​​the bearing eye 18 would also be possible.

[0029] Parallel to the plunger cylinders 12 run, as in Fig. 5 shown are screws 24, by which the head section 20 and the bottom section 22 are connected to each other.

[0030] To protect the exposed sections of the piston rods 16 from contamination and damage, the plunger cylinders 12 each have a protective plate 32 that runs between the cylinder parts 15.

[0031] The hydraulic supply to the plunger cylinders 12 is provided in a known manner by lines that are integrated in the head section 20 or bottom section 22.

[0032] The Fig. Figure 5 shows a (vertical) cross-section of the multi-shell gripper 10 through line AA of the Fig.4. The plunger cylinders 12 and the upper cylinder sections 15 each have two integrated hydraulic connections (or, in other words, each hydraulic connection with two inlets) at their upper end. The hydraulic connections are connected to the pressure chambers of the plunger cylinders 12. The connections can be designed according to DE 20 2005 017 762 U1, i.e., one hydraulic connection leads directly into the adjacent pressure chamber within the upper cylinder section 15, and the other hydraulic connection leads via a connecting pipe, which passes through a longitudinal bore in the piston rod 16, into the pressure chamber on the other side of the piston rod, i.e., within the lower cylinder section 15.

[0033] The hydraulic channels 44 formed within the distributor 40 are directly connected to the hydraulic connections of the cylinders. The hydraulic lines 44 run within the integrated distributor 40 from two inlets 45 on the top, which in turn are connected to hydraulic lines of the rotary drive 50, and then branch outwards in a star-shaped pattern within the distributor 40 to the respective plunger cylinders 12. Two hydraulic channels 44 are provided for each cylinder. Reference symbol list: 1 gripper tray 2 stabilizer links 10 multi-shell grabs 12 plunger cylinders 13 Exclusion 15 Cylinder part 16 Piston rod 18 Bearing eye 20 Head section 22 floor section 24 screws 32 mudguard 34 Base plate 36 Bearing eye 40 distributors 44 Hydraulic channel 45 Entrance 50 rotary drive QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2006 004 856 A1

[0004] DE 20 2005 017 762 U1 [0019, 0032]

Claims

Multi-shell grab (10) comprising at least three double-acting plunger cylinders (12) each with a cylinder and a piston rod (16) slidably mounted therein, a head section (20) with a distributor through which the plunger cylinders (12) can be supplied with hydraulic oil, a bottom section (22) on which at least three grab shells (1) movable by the plunger cylinders (12) can be attached, wherein the plunger cylinders (12) are arranged between the head and bottom sections (20, 22), characterized in that the head and bottom sections (20, 22) are connected to each other by screws (24) running parallel to the plunger cylinders (12). Multi-shell grab (10) according to claim 1, characterized in that the plunger cylinders (12) are each received at their ends in corresponding recesses (13) of the respective head and bottom sections (20, 22). Multi-shell grab (10) according to claim 1, characterized in that the plunger cylinders (12) are each formed by corresponding recesses (13) of the respective head and bottom sections (20, 22). Multi-shell grab (10) according to claim 1, 2 or 3, characterized in that the head section (20) and / or the bottom section (22) is designed as a cast / fired part or welded part. Multi-shell gripper (10) according to one of the preceding claims, characterized in that the piston rods (16) each have a bearing eye (18) via which the piston rods (16) can each be coupled to a gripper shell (1) by means of a connecting rod (2). Multi-shell gripper (10) according to one of the preceding claims, characterized in that the plunger cylinders (12) are each wholly or partially covered by a protective plate (32) which covers a part of the piston rod (16) extending outside the cylinder. Multi-shell gripper (10) according to one of the preceding claims, characterized in that the bottom section (22) comprises a base plate (34) on which bearing eyes (36) for pivoting gripper shells (1) are preferably arranged. Multi-shell gripper (10) according to one of the preceding claims, characterized in that the cylinders have hydraulic connections at the head section end for supplying pressure chambers of the plunger cylinders (12) with hydraulic oil, which are formed by hydraulic channels in a distributor (40). Multi-shell gripper (10) according to claim 8, characterized in that each cylinder has a first and a second hydraulic connection, wherein the first hydraulic connection forms a connection to an immediately adjoining head-side pressure chamber and the second hydraulic connection forms a connection to a bottom-side pressure chamber located on the other side of the piston rod (16), wherein the second hydraulic connection and the bottom-side pressure chamber are connected to each other via a connecting pipe which runs through a longitudinal bore in the piston rod (16), wherein the longitudinal bore preferably runs coaxially to the central axis of the piston rod (16). Multi-shell grab (10) according to one of the preceding claims, characterized in that a rotary drive (50) with a hydraulic rotary feedthrough is provided, which connects to the head section (20), in particular to the distributor (40) and preferably has a bearing eye (52) for fastening the multi-shell grab (10) to a construction machine. Construction machine, in particular hydraulic excavator, with a multi-shell grab according to one of claims 1 - 10, wherein the construction machine preferably comprises a hydraulic system by means of which the plunger cylinders (12) can be supplied with hydraulic oil via the distributor (40).

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