ARM ARRANGEMENT OF A LIFTING DEVICE

Abstract: An arm arrangement of a lifting device, said arrangement comprising two arm elements (4, 5) connected to each other, a first (4) one of which is connected to a support element (6) and the second (5) one is provided with a function member (7) and pivoted, which arrangement is characterized in that it comprises means (10, 11, 12; 17, 18, 19) for moving the point of interconnection of the arm elements along the second arm element (5) between at least two positions. The arm arrangement allows for the lifting device to be used for several purposes, as height digging and depth digging, respectively.

Description: Arm arrangement of a lifting device BACKGROUND OF THE INVENTION AND PRIOR ART The present invention relates to an arm arrangement of a lifting de- vice, said arrangement comprising two arm elements movably con¬ nected to each other, a first one of which is connected to a support element and the second one is provided with a function member and pivoted. Such arm arrangements are especially suitable for applying to the different types of machines that are used for digging, excavation, snow clearance, handling of material in general, etc. In order to apply the invention in a technically applyable connection, the in¬ vention will hereafter for exemplifying purpose be discussed on the basis of its use in connection to machines for the above mentioned purpose. There are today a huge number of machines or arrangements which for their function utilises different types of lifting devices, which in turn comprise different types of arm arrangements. Such lifting de¬ vices are often arranged on vehicles, which are carried on wheels or on bands in order to facilitate their positioning. Arm arrangements are usually hydraulic, but there are for example also tests where they, especially a long time ago, were controlled with the aim of different wire arrangements. According to the different operation steps that different arm ar¬ rangements are supposed to carry out, these arrangements may for example be divided into arrangements intended for height digging, depth digging, loading as well as the type of arm arrangement that is to be found at different types of trucks. These different arm ar¬ rangements are typically of different construction, due to that the different above-mentioned functions require this to obtain the best possible result at each single function. The different arm arrangements are also prevailing in different sizes to a large extent. They are however most often relatively room consuming and room demanding as well as relatively expensive to produce. Their ability to combine different functions is besides considerably limited. This is especially valid for the ability to com¬ bine functions that in principle are as different as depth digging and height digging, which type of combination is not solved on a lifting device according to prior art in a practically satisfying and economi¬ cally advantageous way. These functions are therefore normally di¬ vided into separate lifting devices or arm arrangements for the respective function, so that for example separate vehicles are required for digging and loading. SUMMARY OF THE INVENTION An object with the present invention is to provide with an arm ar- rangement of a lifting device, which in a technically advantageous way allows for combinations of on principle different functions of the lifting device and thereby offers a room saving and cost saving al¬ ternative to prior art within the field of the invention. This object is achieved with an arm arrangement of the type men¬ tioned in the introduction, said arm arrangement comprising means for moving the point of interconnection of the arm elements along the second arm element between at least two positions. By means of that also the second arm element is provided with a function member and pivoted, it will thereby be possible to on one hand move the point of interconnection of the arm elements so that the second arm element is allowed to function as a pivotable stick at the end of the first arm element and thereby making the lifting device suitable for for example depth digging, and on the other hand move the point of interconnection of the arm elements along the second arm element to a position where the second arm element is extending substantially parallel to the first arm element and thereby making the lifting device suitable for for example height digging or loading. In the case that the function member, which might be a digging bucket, a loading bucket or similar, needs to be replaced by some other, for the new function more suitable function member or to be given a new position in relation to the second arm element, this might be obtained by for example conventional fast coupling ar¬ rangements. According to another embodiment of the arrangement according to the invention, the arrangement is characterized by that at least one of the arm elements includes a first arm part and a second arm part movably connected to the first arm part. The arm arrangement and the lifting device are thereby given a larger flexibility considering the possibilities of performing more complicated arm movements. The dividing of at least one of the arm elements into first and second arm parts, which are movably con¬ nected to each other, results in better conditions to achieve good results for the arm arrangement in the different functions as well as support such embodiments, where only one arm arrangement is intended to perform more than two on principle different functions. The arrangement according to the invention is especially advanta- geous according to an embodiment characterized in that it com¬ prises means for moving the point of interconnection of the first and second arm parts along one of the two arm parts between at least two positions, and that the first arm element is pivoted in relation to the support element and the arrangement comprises means for such pivoting. Thereby especially the advantage will be obtained that the second arm arrangement easily provides for a smooth transition from a position where the arm element and included arm parts form a lifting device that is suitable for height digging to a position where they form a lifting device for a truck function, when the second arm ele¬ ment includes the two arm parts, by way of moving the point of interconnection of the arm elements according to what has been de¬ scribed above as well as pivoting of the second arm element in relation to the first arm element. The possibility of moving the point of interconnection of the arm elements along the first arm element may thereby be utilised to achieve a vertical lowering/raising of a function member, for example a fork, connected to this arm part, in conjunction with that the lifting device functions as a truck. As the lifting device instead, when positioned in another mutual position between the arm elements, is intended for digging upwards, the pivoting ability of the first arm element in relation to the support element is advantageous in order to obtain an effective rais¬ ing/lowering of the function member, which in this case might be a digging bucket. If instead the first arm element in the above mentioned case in¬ cludes the two arm parts, a suitably adapted movement of the point of interconnection of the arm elements along the second arm ele¬ ment and pivoting the second arm element in relation to the first arm element and a movement of the point of interconnection of the arm parts along one of these will result in that the lifting device very smoothly may be rearranged, by the movement of the elements and parts between at least two positions, from such a positioning of the arm arrangement that the lifting device principally is suited for depth digging to such a position where it is principally suited for height digging. The pivotability of the first arm element in relation to the support element thereby allows for an effective raising/lowering of the function member, for example a digging bucket, at the height digging function as well as it at the depth digging function allows for the uttermost suitable adjustment in height of the first arm element for this function. According to another preferred embodiment of the arrangement according to the invention, it comprises means for pivoting one of the two arm parts in relation to the second of these arm parts. This characteristic especially results in the advantage that the lifting device very smoothly and easily may be rearranged, by the move- ments and pivoting that this characteristic besides the others, earlier mentioned characteristics enables, in a way that the positioning of the respective arm elements and the arm parts on one hand will be suitable for depth digging and on the other hand will be suitable for height digging or loading as well as suitable for a truck function. According to another preferred embodiment of the arrangement ac¬ cording to the invention, it is characterized in that the support ele- ment is displacably arranged in relation to a lifting device founda¬ tion. This is especially advantageous in the cases where some specific function of the lifting device is favoured of that the support element is located at a closer or a more remote distance from the range of the foundation than normally. The movements between at least two positions take place variably between an arbitrary number of relative positions according to a preferred embodiment. Another possible embodiment is however, that the movements take place between fixed positions, which empirically have been showed to be the most suitable for the re¬ spective function, as height digging , depth digging, loading , truck function etc. The movements are preferably displacements. Further advantages and advantageous characteristics of the inven¬ tion will be apparent from the following description and the other depending claims. BRIEF DESCRIPTION OF THE DRAWINGS According to the accompanying drawings, a detailed description of as examples cited, preferred embodiments of the invention is to fol¬ low below. The drawings show: Fig. 1 a lifting device with an arm arrangement according to the in¬ vention, located in a position suitable for height digging. Fig. 2 an arm arrangement according to Fig. 1 located in a position suitable for depth digging, Fig. 3 an arm arrangement according to Fig. 1 and 2, where the support element is rotated 90° in relation to a foundation lo¬ cated therebelow, and a function member in the form of a fork, and Fig. 4 a further embodiment of an arm arrangement, equipped with specific elements allowing for tilting of the arm arrangement from the position shown in Fig. 3 to the position shown in Fig. 4. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 shows a lifting device 1 in the form of a vehicle carried on wheels, which for example is provided with a room 2 suited for the operator of the lifting device. The lifting device comprises besides an arm arrangement 3, which in turn comprises several components, which will be described below. The arm arrangement 3 comprises here two arm elements 4, 5, which are connected to each other, the first arm element 4 being connected to a support element 6 and the second arm element 5 being provided with a function member 7. One of the two arm elements 4, 5 comprises a first arm part 14; 15 and a second arm part 8, movably connected to the first arm part. Which one of the two arm elements 4, 5 that is to be regarded to comprise the arm parts 14; 15 and 8 is a question of definition. In the following description the first arm element 4 will be regarded as comprising said two, first and second arm parts 14 and 8. Accord¬ ingly, what is to be said according to moving and pivoting of the second arm element 5 in relation to the first arm element 4 as well as regarding moving and pivoting of the second arm part 8 in relation to the first arm part 14 has therefore, in the case that the second arm element 5 is defined to be divided into a first arm part 15 and a second arm part 8, its equivalence in moving and pivoting the first arm part 15 in relation to the second arm part 8 respectively moving and pivoting the second arm element 5 in relation to the first arm element 4. The first arm element 4 is pivoted to a support element 6 arranged on the lifting device by the first arm part 14. By a power member 9, in this case in the form of a hydraulic cylinder, is a means for pivoting the first arm part arranged, and thereby pivoting the first arm element 4 in relation to the support element 6. The pivoting is intended to take place on a level substantially perpendicular to the horizontal level. The arrangement comprises means 10, 11 , 12 for moving the point of interconnection of the first and second arm part along the second arm part 8. These means here comprise a rack 10 arranged on the second arm part 8, a toothed wheel 1 1 connected to the first arm part 14 and geared by a driving device (not shown) as well as by a guide 12, in which the second arm part is intended to be displaced in relation to the first arm part as the geared toothed wheel due to that it engages with the rack effects this displacing. Instead of using a rack 10, a toothed wheel 1 1 , and a guide 12 it is of course possi¬ ble to arrange means of a different type but with the same function as wire and block arrangements, hydraulic cylinders as well as pulleys and similar. The displacement of the second arm part 8 in relation to the first arm part 14 takes place at a somewhat oblique level towards the longitudinal direction of the first arm part 14. The rack 10 extends substantially along the complete length of the second arm part 8, whereby an accordingly large displacement of the second arm part in relation to the first arm part will be possible. The first arm element 4 is at a first end thereof, specifically at an end of the second arm part 8 movably connected to the second arm element 5 which is elongated and at one end equipped with a func¬ tion member 7, in this case in the form of a bucket. The arrangement comprises means 13, 16 for pivoting the second arm element 5 in relation to the first arm element 4. The means 13, 16 are formed by a power member 13 in the form of a hydraulic cylinder as well as of a piece 16 arranged to be affected by the power member 13 and via a hinge connection to the first arm ele¬ ment 4 to pivot in relation to this. The second arm element 5 is con- nected to the piece 16. The arrangement further comprises means for moving the point of interconnection of the arm elements along the second arm element 5. These means are hereby formed by a rack 17 arranged on the first arm element and extending in its longitudinal direction, a toothed wheel 18 connected to the second arm element 5 and geared by a not shown driving arrangement, which toothed wheel engages with the rack 17, as well as a guide 19, which forms the point of interconnection of the arm elements and in which the sec- ond arm element 5 is intended to be moved by a displacement in relation to the first arm element. The guide 19 is arranged on the piece 16, whereby pivoting as well as displacing the second arm element 5 in relation to the arm element 4 will be possible. The rack 19 is further arranged along substantially the complete length of the second arm element whereby an accordingly large displacement of the second arm element in relation to the first arm element will be possible. As well as replacing the means 10, 1 1 , 12 for mutual movement of the two arm parts 8 and 14, the means 17, 18, 19 for the mutual movement of the arm elements 4, 5 may also be re- placed by other, for a desired displacing effect suitable, according movement means. The arrangement also includes means 20, 21 for displacing the support element 6 in relation to the lifting device foundation 22. These means are hereby formed by an arrangement with a rack, a toothed wheel and a guide similar to the earlier described dis¬ placement means and are indicated with a toothed wheel 20 and a rack 21 . Other means for obtaining a displacement of the support element 6 in relation to the foundation 22 is however also possible. The support element 6 is also rotatably arranged in relation to the lifting device foundation 22 and means 23, in this embodiment formed by a conventional turn table, is arranged to obtain the rota¬ tion. The second arm element 5 is arranged to be displaced in relation to the first arm element 4 in a way that the end of the second arm element 5 carrying the function member 7 is arranged in the vicinity of the end of the first arm element 4 where the point of interconnec¬ tion of the respective arm elements is arranged, in order to thereby enable the compact, for height digging suitable embodiment of the arrangement according to Fig. 1. The second arm element is also arranged to be pivotable in relation to the first arm element 4 to such extent that it is displacable, in a position, substantially parallel to a part, in this case the second arm part 8, of the first arm element 4. Thereby the advantage of a compact and little room demanding positioning of the second arm element 5 and the adjacent part of the first arm element 4 will be obtained. By displacing the point of interconnection of the arm parts 8 and 14 along the second arm part 8 or by displacing of the point of inter- connection of the arm elements 4 and 5 along the second element 5, the function member 7 is now displacably arranged to the desired position in relation to the lifting device and the ground. The com¬ plete arm arrangement including the function member 7, may also be pivoted upwards or downwards thanks to the effect of the power member 9 on the first arm element 4. Thus, by pivoting the first arm element 4 upwards from the position shown in Fig. 1 to the position shown in Fig. 2 and to displace the point of interconnection of the first and the second arm part along the second arm part to the position in Fig. 2 as well as also pivoting the second arm element in relation to the first arm element and to displace the point of interconnection of these arm elements along the second arm element, so that this point of interconnection is displaced towards the end 24 of the second arm element that is not having a function member, the arm arrangement may smoothly and elegantly be arranged in such a way that the arm arrangement is now suited for depth digging purposes. The mutual displacement of the arm parts may need a further expla¬ nation. This displacement is preferably such that the point of in¬ terconnection of the arm parts 8 and 14 is arranged to be displaced along the second arm part 8 so that its end 25 which is not con¬ nected to the second arm element 5 is removed from the point of interconnection when the arm arrangement is to be rearranged from depth digging to height digging position and vice versa. To allow for the arm arrangement to in this way switch functions from being suited for height digging to being suited for depth dig¬ ging, the arm arrangement also includes means 26 allowing a fast coupling of different types of function members 7 to the second arm element 5. Thereby, for example a bucket suited for excavating pur- poses may fastly be replaced by a more pronounced bucket for depth digging purposes. Different types of forks as well as drilling devices and similar may of course also be connected to the fast coupling means 26. The arrangement according to the above de¬ scribed, first embodiment having the function member 6 in the form of a fork is illustrated in Fig. 3. The arm arrangement is however jointly with the upper part of the vehicle forming the lifting device 1 , rotated 90° in relation to the position in Fig. 1 and 2. According to this embodiment and having this function member 7, the arrange¬ ment is very suitable for lifting, transporting or loading of material which does not fit into buckets, for example long beams and similar. The function is not totally different from the one that is normally the case with conventional trucks. A second embodiment of the arrangement according to the invention is shown in Fig. 4. This embodiment is more similar to conventional trucks, by adding the characteristic that the arrangement now also includes means 27, 28 for pivoting the second arm part 8 in relation to the first arm part 14. These means are partly formed by a power member 27, in this case in the form of a hydraulic cylinder, which is partly connected at the first arm part and partly connected to the second arm part. These means also includes a piece 28 connected to the second arm part and pivoted to the first arm part 14. In connection to the piece 28, a guide is also arranged, corresponding to the earlier described guide 12 and along which the second arm part is suited to be displaced. By pivoting the second arm part 8 in relation to the first arm part 14, that hereby will be possible, the arm elements and the arm parts of the arm arrangement may be located such that a function very similar to the one of a conventional truck will be obtained for the lifting device 1 . This is possible by the second arm part being suited for being pivoted by the means 27, 28 to a substantially vertical position, whereby the position of the function member 7, here the fork, is approaching the central of gravity of the lifting device 1 , which is especially suitable when heavy weights are to be lifted. The arm arrangement is thereby arranged to be tilted either by way of pivoting the second arm part in relation to the first arm part or by pivoting the second arm element 5 in relation to the first arm element 4. The arrangement is also arranged to perform lifting by displacing the point of interconnection of the arm elements 4, 5 along the second arm element 5 or by displacing the point of interconnection of the arm parts 8, 14 along the second arm part 8. Lifting may also take place by pivoting the first arm element in relation to the support element 6, but in this case the lifting does not take place in a strictly vertical direction. The arm arrangement according to the invention thus makes the lifting device very suited to function for height digging purposes, and depth digging purposes as well as for more pronounced truck functions and offers thereby a very advantageous combination arrangement. In the above description it has been assumed that the first arm ele- ment 4 includes the two arm parts 8, 14. An according discussion may of course take place on the condition that the second arm element 5 includes a first arm part 15 and a second arm part 8. Considering a mutual movement and pivoting of the second arm ele¬ ment 5 in relation to the first arm element 4 as well as a movement and pivoting of the first arm part 15 in relation to the second arm part 8, these movements correspond to what has been told above according to a movement and pivoting of the second arm part 8 in relation to the first arm part 14 and a movement and pivoting of the second arm element 5 in relation to the first element 4 respectively. It is also to be noted that in such cases where the second arm ele- ment 5 is not pivoted in relation to the first arm element 4, its ability to pivot is due to the ability of the arm element 4 to pivot in relation to the support element 6. It should also be mentioned that the invention of course not in any way is limited to the above described, preferred embodiments, but that several possibilities of modifications of these embodiments will be apparent for a man skilled in the art. It is for example possible that one or both of the two arm elements includes further arm parts, which also lies within the scope of the in¬ vention and is covered in the enclosed claims, in the way these claims are formulated. It should finally also be established that the arm arrangement is es- pecially suitable for being set in different positions, by way of a mu¬ tual movement and pivoting of therein included arm elements and/or arm parts, whereby each position is especially suited for a special function of the arm arrangement. The arm arrangement is preferably forming part of a completely or partly hydraulically controlled lifting device and the functions preferably intended are two or more of the height digging, depth digging, loading and the truck function etc.

Claims: Claims 1 . An arm arrangement of a lifting device, said arrangement com¬ prising two arm elements (4, 5) movably connected to each other, a first (4) one of which is connected to a support element (6) and the second (5) one is provided with a function member (7) and pivoted, characterized in that it comprises means (10, 1 1 , 12; 17, 18, 19) for moving the point of interconnection of the arm elements along the second arm element (5) between at least two positions. 2. An arrangement according to claim 1 , characterized in that at least one of the arm elements (4, 5) com- prises a first arm part (14; 15) and a second arm part (8) connected to the first arm part (14). 3. An arrangement according to claim 2, characterized in that it comprises means (17, 18, 19; 10, 1 1 , 12) for moving the point of interconnection of the first and second arm part along one (8; 15) of the two arm parts between at least two posi¬ tions. 4. An arrangement according to claim 2 or 3, characterized in that it comprises means (27, 28; 13, 16) for pivoting the first (8; 15) of the two arm parts in relation to the second (14; 8) of these arm parts. 5. An arrangement according to any of the preceding claims, characterized in that it comprises means (13, 16; 27, 28) for pivoting the second arm element (5) in relation to the first arm element (4). 6. An arrangement according to any of the preceding claims, characterized in that the support element (6) is rotatably arranged in relation to a lifting device foundation (22) and means (23) are ar¬ ranged to create the rotation. 7. An arrangement according to any of the preceding claims, characterized in that the support element (6) is displacably arranged in relation to a lifting device foundation (22) and means (20, 21 ) are arranged to create such a displacement. 8. An arrangement according to any of the preceding claims, characterized in that the first arm element (4) is pivoted in relation to the support element (6) and means (9) are arranged to create such a pivoting. 9. An arrangement according to any of the preceding claims, characterized in that the support element (6) is arranged on a vehicle. 10. An arrangement according to any of the preceding claims, characterized in that it comprises means for fast coupling of differ¬ ent types of function means (7) to the second arm element (5).

Inventors: BLOM KURT, BLOM, KURT
Applicants: BLOM ANDREAS, BLOM KURT, BLOM, ANDREAS, BLOM, KURT
Application year: 1996
Main classification: E02F3
IPC codes: B66F9, E02F3