Abstract
An excavator includes an articulated boom and a balancing mechanism that assists a movement of the articulated boom from a lower position to an upper position by applying a pulling force on the articulated boom. The balancing mechanism comprises a balancing member that generates an assisting force and a force transfer mechanism that couples the balancing member with the articulated boom. The force transfer mechanism comprises a link mechanism that transfers the assisting force from the balancing member to the articulated boom at a transmission ratio independent from a position of the articulated boom.
Claims
1. An excavator comprising: an articulated boom; and a balancing mechanism that assists a movement of the articulated boom from a lower position to an upper position by applying a pulling force on the articulated boom, wherein the balancing mechanism comprises a balancing member that generates an assisting force and a force transfer mechanism that couples the balancing member with the articulated boom, wherein the force transfer mechanism comprises a link mechanism, wherein the link mechanism comprises a rigid force transfer link coupled to the articulated boom at one end thereof and a guiding link coupled to a platform of the excavator at one end thereof, wherein the rigid force transfer link and the guiding link are connected at their respective other ends at a connecting portion of both links, wherein the balancing member is coupled to the connecting portion, and wherein the link mechanism transfers the assisting force from the balancing member to the articulated boom at a transmission ratio independent from a position of the articulated boom.
2. The excavator of claim 1, wherein the articulated boom is hingedly coupled to the platform of the excavator, wherein the rigid force transfer link is hingedly coupled to the articulated boom at the one end thereof, and wherein the guiding link is hingedly coupled to the platform at the one end thereof.
3. The excavator of claim 1, wherein the balancing member is coupled to the connecting portion by another rigid force transfer link.
4. The excavator of claim 1, wherein the balancing member comprises a pressure cylinder.
5. The excavator of claim 4, wherein the pressure cylinder is inversely arranged and exerts a pushing force.
6. The excavator of claim 1, wherein the guiding link comprises a length-adjustable hydraulic cylinder.
7. The excavator of claim 6, wherein the transmission ratio of the assisting force applied on the articulated boom by the link mechanism is adjusted by adjusting a length of the length-adjustable hydraulic cylinder.
8. The excavator of claim 1, wherein the link mechanism comprises another rigid force transfer link connected at one end thereof to the connecting portion of the link mechanism.
9. The excavator of claim 8, wherein one of the rigid force transfer links is hingedly coupled at its respective ends to the articulated boom and the connecting portion.
10. The excavator of claim 9, wherein the other of the rigid force transfer links is hingedly coupled at its respective ends to the balancing member and the connecting portion.
11. An excavator comprising: a platform; an articulated boom hingedly coupled to the platform; and a balancing mechanism at least partially assisting a movement of the articulated boom from a lower position to an upper position by applying a pulling force on the articulated boom, wherein the balancing mechanism comprises a balancing member configured and arranged for generating an assisting force, wherein the balancing member comprises a pressure cylinder, wherein the balancing mechanism further comprises a link mechanism indirectly and force-transmittingly coupling the balancing member with the articulated boom for transferring the assisting force to the articulated boom via the link mechanism, wherein the link mechanism comprises a rigid force transfer link hingedly coupled to the articulated boom at one end thereof, another rigid force transfer link hingedly coupled to the balancing member at one end thereof, and a guiding link hingedly coupled to the platform at one end thereof, wherein the guiding link comprises a length-adjustable hydraulic cylinder, and wherein the rigid force transfer links and the guiding link are connected at their respective other ends forming a connecting portion of the three links.
12. The excavator of claim 11, wherein a transmission ratio of the assisting force applied on the articulated boom by the link mechanism is adjusted by adjusting a length of the length-adjustable hydraulic cylinder.
13. The excavator of claim 11, wherein the pressure cylinder is inversely arranged and exerts a pushing force.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and:
(2) FIGS. 1-3 show different embodiments of excavators according to the present disclosure;
(3) FIG. 4A shows a side view of an excavator according to a further embodiment of the present disclose and FIGS. 4B and 4C show different views of a pulley of a transmission of the excavator shown in FIG. 4A; and
(4) FIGS. 5-26 show different further embodiments of excavators according to the present disclosure.
(5) All figures are only schematic depictions of exemplary embodiments in which, in particular, distances and dimensional correlations are not presented to scale.
DETAILED DESCRIPTION
(6) The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description.
(7) FIG. 1 shows a side view of an excavator 1 according to an embodiment of the present disclosure. The excavator 1 comprises a platform 2, also called top frame, which is rotatably coupled to an undercarriage 3 having tracks 5. On the platform 2, a boom 4 is hingedly mounted at a hinge portion 24, i.e. at a first end of the boom 4, and an operator's cab 40 is provided. The boom 4 is rotatable about a rotation axis A. A dipper 6, also called stick or bucket arm, is hingedly coupled to the boom 4. A bucket 7 is hingedly coupled to the dipper 6. The boom 4 is movable by means of a first hydraulic cylinder 50 supported on the platform 2 and coupled to the boom, the dipper 6 is movable by means of a second hydraulic cylinder 52 supported on the boom and connected to the dipper, and the bucket is movable by means of a third hydraulic cylinder 54 supported on the dipper and coupled to the bucket 7. It is to be noted, that although only one first cylinder 50 is shown in FIG. 1, it is possible to use two hydraulic cylinders 50, one on each side of the boom 4. In the configuration as shown, the hydraulic cylinder 50 exerts a pushing force on the boom 4 in order to move the same. Inside the platform 2, a motor (not shown) is provided for generating power used for moving the excavator and for actuating the hydraulic cylinders 50, 52, 54.
(8) In order to assist the boom 4, and consequently the cylinders 50 in moving the boom from a lower position to an upper position, the excavator 1 further comprises a balancing mechanism 8 which is configured to apply a pulling force on the boom 4. In this way, less power has to be applied on the boom 4 by the first hydraulic cylinder 50 in order to move the boom 4 allowing to use smaller hydraulic cylinders. Furthermore, as a pulling force is applied on the boom 4 by means of the balancing mechanism, the response characteristics are enhanced because the force necessary for moving the boom 4 can be generated faster in the first hydraulic cylinder 50.
(9) The balancing mechanism 8 as shown in FIG. 2 comprises a balancing member 10 for generating an assisting force and a force transfer mechanism a for transferring the force generated by the balancing member 10 to the boom 4. In the present embodiment, the balancing member 10 is a pressure cylinder 13 comprising nitrogen as pressure gas and is mounted to the platform 2 at one end and coupled to the force transfer mechanism 11 at the other end. Here, it is to be noted that the general construction of the excavator as described so far also applies for all embodiments other than the one described with respect to FIG. 1.
(10) The force transfer mechanism as shown in FIG. 1 comprises a flexible link 12 which in this embodiment is a wire rope 21. However, a chain (not shown) could also be used instead of the wire rope 21. The wire rope 21 is at one end coupled to the pressure cylinder 13 at a coupling portion 14 in such a manner that a direction of a force generated by the pressure cylinder 13 is aligned with an extension direction of the wire rope 21. At the other end, the wire rope 21 is coupled to a coupling device 20 which is configured to transfer a force from the wire rope 21 to the boom 4 such that an assisting moment assisting the movement of the boom 4 is generated on said boom 4.
(11) The coupling device 20 is structured such that a force introduced into the coupling device 20 by the wire rope 21 is transferred to the boom 4 at a fixed ratio independent from the position of the boom 4. For that, the coupling device 20 comprises a force transfer device 22 fixedly coupled to the boom 4 such that the force transfer device 22 and the boom are integrally movable. For example, the force transfer device 22 can be welded to the boom 4 or may be fixedly attached by means of threaded bolts or screws. The force transfer device 22 comprises a peripheral surface 23 for guiding the wire rope 21 at a predetermined distance from hinge portion 24 at which the boom 4 is articulated.
(12) In the present embodiment, the peripheral surface 23 of the force transfer device 22 follows a circular path having its center on center axis A. Center axis A is aligned with rotational axis B of the boom 4 in the hinge portion 24. The wire rope 21 is coupled to the force transfer device 22 at a fixation portion 22b thereof, i.e. in FIG. 1 on the left side peripheral surface end of the force transfer device 22, such that a portion 12a of the wire rope 21 contacts a predetermined section of the peripheral surface 23 when the boom 4 is in the position as shown in FIG. 1. This position of the boom as shown can also be referred to as lower position. Accordingly, when the boom is moved in the counter-clockwise direction, the dimension of the portion 12a will increase whereas when the boom 4 is moved in the clockwise direction, the wire rope 21 will unwound from the force transfer device so that the dimension of the portion 12a will decrease. Since the peripheral surface follows a circular path about the hinge axis A, a force transferred on the force transfer device 22 is always converted into torque acting on the boom 4 with the same ratio. In other words, if the force generated by the pressure cylinder 13 is constant over the entire movement area of the boom 4, a corresponding constant torque will be generated on the boom 4.
(13) FIG. 2 shows a configuration of an excavator 1 which differs from the configuration as shown in FIG. 1 in that the pressure cylinder 13 is arranged inversely. In this configuration, the rear end of the pressure cylinder 13, which is supported against the platform 2 faces the boom 4 and the coupling portion 14 is located on the right side in FIG. 2. In this embodiment, the coupling portion 14 comprises a link 14a which allows a coupling of the wire rope 21 at a position which is laterally offset with respect to the pressure cylinder 13. In this configuration, the wire rope 13 extends along and parallel to the pressure cylinder 13.
(14) FIG. 3 shows a configuration of an excavator 1 which differs from the configuration as shown in FIG. 1 in that the pressure cylinder 13 is arranged inversely similar to the embodiment shown in FIG. 2. However, in the embodiment of FIG. 3, the force transfer mechanism 11 comprises a deflection pulley 11a which deflects the wire rope 21, about 180 in the example as shown. With this configuration, the direction of a pulling force exerted on the pressure cylinder is independent from a dimension of the force transfer device 22. In this embodiment, the pressure cylinder extends substantially horizontally and this will not change even if a differently shaped force transfer device 22 is used.
(15) FIG. 4A shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 3 in that the force transfer mechanism 11 comprises a transmission realized by a cone-shaped pulley 11b, i.e. a pulley shaped in the form of a truncated cone, instead of the deflection pulley 11a as shown in FIG. 3. In this embodiment, the transmission is generated by means of a diameter difference of between pulley surface portions where a contact of the wire rope 21 with the pulley is established or released. In the embodiment as shown in FIG. 4A, these pulley surface portions are provided on the left and right end of the conical surface of the cone-shaped pulley 11b as shown in FIGS. 4B and 4C. In the embodiment of FIG. 4A, the wire rope 21 coming from the pressure cylinder 13 makes contact with the surface of the cone-shaped pulley 11b on the left side in FIG. 4C, i.e. at a portion of the pulley having the greatest diameter. The wire rope 21 is then wound about the outer surface of the pulley multiple times and leaves the pulley surface at a portion having smallest diameter. In this way, the output force on the wire rope 21 is increased by the pulley. Thus, the cone-shaped pulley 11b provides a reliable and cost-efficient transmission.
(16) FIG. 5 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 1 only in that the pressure cylinder 13 is coupled to a lower portion of the platform 2 so that a larger portion 12a of the wire rope 21 which can contact a predetermined section of the peripheral surface 23 is available. With this configuration, an assisting range is increased.
(17) FIG. 6 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 1 only in the construction of the coupling device 20. The coupling device 20 is structured such that a force introduced into the coupling device 20 by the wire rope 21 is transferred to the boom 4 at a variable ratio dependent on the position of the boom 4. For that, the coupling device 20 comprises a force transfer device 22a fixedly coupled to the boom 4 such that the force transfer device 22a and the boom 4 are integrally movable. The force transfer device 22a comprises a peripheral surface 23a which comprises a contour defined by a path extending about center axis A while a radial distance with respect to the axis A increases when following the path in clockwise direction in FIG. 5. With increasing radial distance from axis A a moment is correspondingly increased. With the configuration as shown in FIG. 5, the force transfer device 22a is structured such that a force introduced into the force transfer device 22a by the wire rope 21 generates a maximum torque when the boom is rotated to the lowest position. When the boom 4 is rotated in the clockwise direction, the point at which force from the wire rope 21 is introduced into the force transfer device 22a moves towards axes A, B so that a distance for torque generation is reduced. Accordingly, the transmission ratio varies with the movement of the boom 4.
(18) FIG. 7 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 6 only in that the force transfer mechanism 11 comprises a deflection pulley 11c which is arranged between the pressure cylinder 13 and the coupling device 20. By using the deflection pulley 11c, a force transferred via coupling portion 14 is always transferred in the same direction, which in the embodiment as shown is a substantially horizontal direction.
(19) FIG. 8 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 7 only in that the force transfer mechanism 11 comprises a deflection pulley 11d which is configured like the cone-shaped pulley 11b as shown in FIGS. 4A, 4B and 4C. Thus, deflection pulley 11d additionally comprises transmission capabilities as described above with respect to the embodiment as shown in FIGS. 4A, 4B and 4C.
(20) FIG. 9 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 2 only in that coupling device 20 is structured as described in connection with the embodiment as shown in FIG. 5.
(21) FIG. 10 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 7 in that the pressure cylinder is inversely arranged in a manner as described with respect to the embodiment as shown in FIG. 2.
(22) FIG. 11 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 3 only in that coupling device 20 is structured as described in connection with the embodiment as shown in FIG. 5.
(23) FIG. 12 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 8 only in that the pressure cylinder is inversely arranged in a manner as described with respect to the embodiment as shown in FIG. 2.
(24) FIG. 13 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 4 only in that coupling device 20 is structured as described in connection with the embodiment as shown in FIG. 6.
(25) FIG. 14 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 5 only in that coupling device 20 is structured as described in connection with the embodiment as shown in FIG. 6.
(26) FIG. 15 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 7 only in that instead of coupling device 20 a link mechanism 60 is used for transferring a force introduced into the link mechanism 60 by the wire rope 21 is transferred to the boom 4 at a fixed ratio independent from the position of the boom 4. For that, the link mechanism 60 comprises a rigid force transfer link 62 connected to the end of the wire rope 21 at a connecting portion 66 and hingedly coupled to the boom 4 at the other end thereof and a rigid guiding link 64 coupled to the connecting portion 66 between wire rope 21 and force transfer link 62 at one end and hingedly coupled to the platform 2 at the other end. Accordingly,
(27) FIG. 16 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 8 only in that instead of coupling device 20 a link mechanism 60 according to the embodiment as shown in FIG. 15 is used.
(28) FIG. 17 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 3 only in that instead of coupling device 20 a link mechanism 60 according to the embodiment as shown in FIG. 15 is used.
(29) FIG. 18 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIGS. 4A, 4B and 4C only in that instead of coupling device 20 a link mechanism 60 according to the embodiment as shown in FIG. 15 is used.
(30) FIG. 19 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 15 in that the force transfer mechanism is entirely constructed from rigid links 14a, 62, 64, and 68. In other words, the wire rope 21 as well as the deflection pulley 11c are replaced by links 68 and 14a. As regards the link 14a, reference is made to the above embodiments which also include this link 14a.
(31) FIG. 20 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 19 in that the pressure cylinder is inversely arranged and exerts a pushing force.
(32) FIG. 21 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 15 in that the link mechanism 60 comprises a length adjustable hydraulic cylinder 70. By adjusting the length of the hydraulic cylinder 70 a transmission ratio of the force applied on the boom 4 by link 62 can be adjusted.
(33) FIG. 22 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 16 in that the link mechanism 60 comprises a length adjustable hydraulic cylinder 70 as described with respect to the embodiment shown in FIG. 21.
(34) FIG. 23 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 17 in that the link mechanism 60 comprises a length adjustable hydraulic cylinder 70 as described with respect to the embodiment shown in FIG. 21.
(35) FIG. 24 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 18 in that the link mechanism 60 comprises a length adjustable hydraulic cylinder 70 as described with respect to the embodiment shown in FIG. 21.
(36) FIG. 25 shows a configuration of an excavator 1 according to a further embodiment which differs from the configuration as shown in FIG. 19 in that the link mechanism 60 comprises a length adjustable hydraulic cylinder 70 as described with respect to the embodiment shown in FIG. 21.
(37) It is to be noted that buckets of different sizes can be used on the bucket arm. Furthermore, it is also possible to use other tools instead of the bucket. The load transfer mechanism 11 can be adapted to the bucket size or tool used in order to assist a movement of the boom in the upward direction in an optimum way. For that, it is possible to provide elements with adjustable transmission ratios. For example, the force transfer device can be arranged releasably locked to the boom and can be exchanged with another force transfer device having a different shape and better suiting the tool or bucket size as mounted. It is also possible to provide a force transfer device having several different force transfer sections in a direction of the axis B and a force transfer changing mechanism being able to shift between the force transfer sections in order to adapt the force transfer device to the bucket size or load.
(38) In conclusion, it is pointed out that terms like comprising or the like are not intended to rule out the provision of additional elements or steps. Let it further be noted that a or an do not preclude a plurality. In addition, features described in conjunction with the different embodiments can be combined with each other however desired. It is also noted that the reference numbers in the claims are not to be construed as limiting the scope of the claims. Moreover, while at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist.
(39) It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.
