ARRANGEMENT OF DRIVE WHEELS

Abstract: An arrangement for producing the drive force for vehicles. The arrangement comprises a frame plate (17), to be rotated around a first shaft (B-B) being substantially perpendicular to the plane of the running base (P). Said plate (17) is rotated around the said first shaft (B-B) by a motor (15) and a power transmission (16). In a set of wheels (10), wheels (10a, 10b, 10c; 10a', 10b', 10c') are turnably connected to the said plate (17) by means of articulated shafts (12, 18). The wheels are guided to run, by a first steering mechanism (21, 27, 28) during rotation of the said plate (17), along such tracks (ra, rb, rc) that the axis lines (L) of the wheels (10) intersect each other substantially on the same line (A). A second steering mechanism (22, 23, 24) is coupled to the said first steering mechanism (21, 27, 28) so that the line (A) can be deviated in relation to the axis of rotation (B-B). Thus is produced a drive force and a tractive movement by means of rotation of the said plate (17). The said second steering mechanism (22, 23, 24) includes a steering lever (22) mounted to the frame (13) by means of a universal ball joint (23). By the said steering lever (22) the line (A) is deviated arbitrarily so that both the direction of drive and the speed of travel of the equipment can be selected freely and steplessly.

Description: Arrangement of drive wheels The subject of the present invention is an arrangement of drive wheels, which is designed -for pro¬ ducing the drive force for vehicles, various transfer devices, or equivalent, the said arrangement comprising a combination of a) a construction, such as a frame plate, to be rotated around a first shaft, the said first shaft being substantially perpendicular to the plane of the running base, b) a motor and a power transmission, by means of which the said construction is rotated around the said first shaft, c) a set of wheels, whose wheels are turnably connected to the said first construction by means of articu¬ lated shafts or equivalent, d) a first steering mechanism, by means of which the wheels of the said set of wheels are guided to run, during rotation of the said first construction, along such tracks that the axis lines of the wheels inter¬ sect each other substantially on the same straight line or substantially at the same point, e) a second steering mechanism, which is coupled to the said first steering mechanism so that the line or point of intersection of the axis lines of the wheels in the set of wheels can be deviated in relation to the axis of rotation of the said first construction so as to produce a drive force and a tractive move¬ ment by means of rotation of the said first con- struction while the wheels of the set of wheels are in contact with the running base. The operation of transport platforms and trac¬ tive equipment known in prior art and making use of wheels and/or sets of wheels is ' ^based thereon that the ' power is transmitted to the drive wheels by means of various gearboxes, torque converters, etc. known power transmission devices, the said drive wheels being placed O PI so that the direction of rotation is equal to the desired direction of movement. The turning of prior-art transport equipment and tractive equipment is arranged either by means of tractive wheels and/or by means of separate steering wheels so that the wheels can be turned in the desired direction by means of a separate steering mechanism. In most cases such a steering system does not permit turning by more than 45 degrees, which results in a remarkably high requirement of turning space. Apparatuses are also known in prior art in which all the wheels can be turned in order to produce the desired steering effect. In these apparatuses the solutions of power transmission and steering mechanisms are, however, quite complicated, and their industrial manu acture is expensive. In the solutions of transport platforms and tractive equipment in common use it has not been possible, without a technically complicated and heavy power trans- mission, to produce high tractive effort, which is fre¬ quently quite necessary in the situation of starting to move. The transmission ratios of the drive axles are, relatively speaking, low, which has resulted in heavy " axles and in wheels of large dimensions. In order to eliminate the above drawbacks and defects in respect of the transport platforms and trac¬ tive equipment, as well as in view of other services required by industry, storage, transport trade, and, e.g. by hospital operations in their transfer and transport duties, the objective of the present invention is to provide a new arrangement of drive wheels, whose exclu¬ sive purpose is not only to eliminate drawbacks present in prior art in respect of power transmission and steering but also to permit technico-economically optimum produc- tion costs for the new arrangement. An arrangement of drive wheels of the type defined above initially is previously known from the O published patent application DE-OS 1,911.410 (date of publication 24th September, 1970) . By means of the arrangement in accordance with this cited publication, it is possible to eliminate several of the drawbacks men- tioned above. The objective of the present invention is a further development of the arrangement of drive wheels known from the said published application, especially in respect of its steering mechanism. According to the said cited publication, the turning wheels of the arrangement are connected to rods, whose inner ends are provided with loops. A steering pin is fitted into the said loops, which steering pin is shifted by means of one steering motor along tracks of the shape of the circumference of a circle. The radius of the said circle can be selected by means of a second steering motor. The technical accomplishment of such a steering arrangement becomes complicated and expensive. In order to eliminate the drawbacks stated above and to reach the other goals of the invention, the invention is mainly characterized in that the said second steering mechanism includes a steering lever mounted to the frame of the equipment by means of a universal ball joint or equivalent and fitted so that by means of the said one steering lever it is possible to deviate the line or point of intersection of the axis lines of the wheels of the set of wheels arbitrarily so that both the direction of drive and the speed of travel of the equip¬ ment can be selected steplessly and freely by means of one selection of the position of the said steering lever. The invention is based on an alteration of the internal equilibrium of forces in a wheel set consisting of wheels which are, by means of particular power trans¬ mission units, made to rotate concentrically along a circular track, which are connected to one another in a certain way, which are in themselves known, and which have diameters of appropriate size, so that the wheel set proceeds in the desired direction at the selected speed, O PI while it is, by means of the frame construction, connec¬ ted to a stationarily mounted wheel or set of wheels or to a second or several drive wheel units of corresponding type. The arrangement of drive wheels in accordance with the invention offers, e.g., the following advan¬ tages, which are important in practice: 1) very simple methods and devices can also be used for the power transmission, 2) in situations of starting and at low travel speeds remarkably high tractive forces are achieved with little power, 3) the transmission becomes by itself, without gear¬ boxes or variators, stepless, and the speed and direction of travel in all directions can be con¬ trolled by means of one control device, 4) good steering quality is obtained, and an apparatus provided with two drive wheel units in accordance with the invention can turn -and, if required, even revolve on the spot, 5) in vehicles provided with a set of wheels in accord.- ance with the invention, separate brakes are not necessarily required, 6) the technical solution can be accomplished by very simple and economical means, and the purpose of use determines the standard of the solution used, 7) the sets of wheels in accordance with the invention can be applied to automatic steering systems by simple means, 8) if necessary, the invention permits the use of wheels of small dimensions, because the drive is not accomplished by means of axle transmission, 9) another important advantage of the invention is that, when a steering bar, preferably a steering lever, is used that is, in accordance with the invention, moun¬ ted to the frame of the apparatus by means of a universal ball joint or equivalent, by means of one OM steering bar or lever it is possible to select both the direction of travel and the speed of travel of the apparatus steplessly and according to free choice In this way the steering of the tractive equipment can be made precise and quick and logical, e.g., so that the apparatus travels exactly in the direction towards which the steering lever is deviated and at a speed that corresponds the angle of deviation of the steering lever. The drive wheel arrangement in accordancd with the invention can be applied to all such transport, traction and shifting duties that take place on a rea¬ sonably smooth running base and in which substantial requirements are imposed on the steering quality, tiactiαα capacity, and in which high travel speed is not the most decisive factor. Out of possible fields of applications, the following could be mentioned in particular: - various traction vehicles, - transport platforms and working planes at warehouses, factory halls, and workshops, - unmanned traction vehicles and transport systems operating by means of automatic methods or with mechanical etc. limiters, - wheelchairs and various transfer equipment for hospitals and institutions. Traction vehicles and transport equipment pro¬ vided with an arrangement of wheels in accordance with the invention may be provided with various lifting mecha¬ nisms, whereby the possibilities of use of the equipment can be made more ve-rsatile. Below, the invention will be described in detail with reference to certain exemplifying embodiments of the invention illustrated in the figures of the attached drawing, the invention being, however, not restricted to the details of the said embodiments. Figure 1 is a side view of a vehicle provided with a drive wheel arrangement in accordance with the OMPI present invention. Figure 2 shows the same as Fig. 1, as viewed from above. Figure 3 is a schematical presentation of the geometry of components of a wheel arrangement in accord¬ ance with the present invention. Figure 4 shows an embodiment related to the design of the steering linkage of a wheel arrangement in accordance with the invention. Figure 5 shows an example on the linkage to the frame plate of the wheels in a wheel arrangement in accordance with the invention. Figure β shows an example on the coupling of the steering rods of a wheel in the wheel arrangement in accordance with the invention. Figure 7 shows the principle of travelling of the arrangement of wheels in accordance with the __nve_ιtiα_ι Figures 1 and 2 illustrate an apparatus wherein a wheel set 10 in accordance with the invention is mounted to the same frame 13 together with two wheels 11a and lib mounted stationarily to the forks 14. The apparatus con¬ sists of a frame 13, onto which the electric motor 15, operating as the power source, is mounted. By means of the V-belt 16 driven by the electric motor 15_. a movement rotating in the desired direction is transmitted to the frame plate 17 of the wheel set. In the exemplifying embodiment shown in Figures 1 and 2 the frame plate 17 rotates in the direction R, clockwise. The opposite direction of rotation is equally good-. The forks 19 are mounted to the frame plate 17 by means of vertical shafts 18, and the wheels 10a, 10b and 10c of the wheel set 10 are mounted to the forks by means of the shafts 20. The steering rods 21 are linked at one end to the forks 1 s in the same position in respect of each fork 19, and at the other end to the steering lever 22, which is by means of the universal ball joint 23 mounted to the socket 24 in the frame 13- The frame plate 17 of the wheel set OM 10 is mounted -to the frame 13 of the apparatus by means of a ball bearing 25. As was stated above, the other end of the apparatus is supported on wheels 11a, lib, which are mounted to the frame 13 by the intermediate of rolling shafts 2β and stationary forks 14. When the electric motor 15 is connected either with an external supply of current (not shown) or with accumulators (not shown) installed in connection with the frame 13, the wheel set starts, being rotated by the frame plate 17, revolving clockwise and the apparatus remains stationary as long as the steering lever 22 is in the vertical position shown in Fig. 1. When the steering lever 22 is shifted forwards in the direction I, the lower end of the lever, to which the steering rods 21 are mounted, moves in the opposite direction. Corres¬ pondingly, the steering rods 21 turn the wheels 10a, 10b and 10c, and the wheel set 10 and, along with it, the whole apparatus starts moving constantly in the direction r. When the steering lever_ 22 is restored to the initial position, the movement is discontinued and the apparatus is stationary. At that time the wheels 10a, 10b and 10c revolve concentrically around the journalling centre of the steering lever 22 and of the steering rods 21. If the steering lever 22 is turned in the direction II, the apparatus starts moving in the same direction. When the lever is shifted in the direction III or IV, the wheel set 10 consisting of the wheels 10a, 10b and 10c produ¬ ces a movement in the same direction and the apparatus as a whole, turns towards the said direction with a turning radius characteristic of the combination formed by the set of wheels of the turning wheels and by the wheels mounted stationarily. All directions of movement between the said main directions I,II,III,IV are also possible. Generally speaking, the apparatus described above starts its movement exactly in the direction towards which the steering lever 22 is shifted. The arrangement of drive wheels illustrated in Figures 1 and 2 consists of wheels 10 that have been made, by means of particular power transmission mechanisms, to revolve on the plane of travel clockwise, which wheels are shown in Figures 1 and 2 as consisting of three wheels 10a, 10b and 10c. The axes or axis lines of the wheels 10 intersect each other in the same projection point A of the plane of rotation. The axis centres 12 of the wheels 10 revolve concentrically around the symmetry- centre axis B-B of the power transmission of the wheel set. In the situation shown in Figures 1 and 2, . wherein point A •= B, the wheels 10 revolve around the centre axis B-B and the wheel set does not make progress in any direction. When the point of intersection A of the axi.s lines L is deviated by the equipment described above from the position A = B shown in Figures 1 and 2, by the effect of their movement of rotation the wheels 10 produce a force that is directed at the wheel set and whose directic-i is perpendicular to the line AB. According to Figure 3 _ the line of effect of the said force can be defined as follows: when the wheel set is placed on the xy-plane so that the point B is at the origo and the wheels 10 revolve clockwise around the point B, the force acting upon the wheel set and producing the progress T is direc¬ ted in the positive direction of the y-axis when the point A is shifted along the x-axis in its positive direction. In Figure 3 r & ) ^ and r illustrate the routes of passage of the individual wheels 10a, 10b and 10c of the wheel sets on the plane of travelling when the wheel set makes progress in accordance with the 1 principle described above. The axis lines L of the wheels 10 do not have to intersect each other in the same point, but' for the accomplishment of the inventive idea it is sufficient if they intersect the same normal of the plane of rotation whose projection on the plane is point A, this in the case in which different wheels of the wheel set have diameters of different size, as compared with each other. If the deviating of the wheels 10 from the position of equilibrium A = B is performed from an exter¬ nal point, in relation to the axis centres of the indi- vidual wheels, in accordance with the Figures 5 and 6, or if the suspension of the wheels 10 has been performed eccentrically, this produces forces acting upon the mechanism controlling the point A which forces attempt to restore the point A to point B. In the above case, as soon as the force deviating the point A is eliminated, the wheel set attempts to restore the state of equ__l____±u_n. When a wheel set 10 of the type described above is connected together with either a stationary ordinary wheel set 11a, lib or one or several special wheel sets 10 in accordance with the invention, mounted to the same frame, the steering mechanism of the said special wheel set being, in known ways, synchronized with the first-mentioned wheel set, an apparatus is produced whose running can be controlled in a highly versatile- a . The traction device described above and illus¬ trated in the figures is suitable for use in many different apparatuses, e.g., as a traction unit for a wheelchair or equivalent. An embodiment of the invention in which two wheel sets of the type described above are mounted to the same frame and base is particularly well suitable for traction and transportation duties on aeroplanes, terminals, or factory and warehouse halls. In such a case the frame of the traction device may be provided with a lifting mechanism for automatic securing of freight car pallets or cargo platforms. According to Figure 3, the wheel set 10 subject of the invention consists of wheels 10a,10b,10c,10a τ ,10b ' , 10c', linked to the frame plate 17 by means of different radii, the axis centres 12 of the said wheels revolving concentrically around the point B and the axis lines L of the said wheels intersecting each other in the same point A or on the same line, whose projection in the c:-:? plane parallel to the frame plate 17 is the said point A. According to Figure 4, in order to carry out the invention, the controlling of the wheels lOe can be arranged so that the fork 19 of the wheels is fastened to a telescope construction 27. 28, which is at the opposite end connected to the said point A or to a cor¬ responding straight line, to which the corresponding telescope arms 27. 28 of the various wheels lOe are coupled. In this way the arms 27, 28 control the wheels so that, when the frame plate 17 revolves,, the axis lines L of the wheels lOe intersect each other in the same point A, whereby the desired speed and direction of movement of the drive wheel in accordance with the inven¬ tion is produced by varying the position of the said pcriπfc. in relation to the centre of rotation B of the frame plate 17. According to Figures 5 and β, the wheels lOf are fastened to the fork 19 so that the steering rods 29 are attached to the forks.19 at a certain distance d in relation to the plane T of the axes of rotation 20 of . the wheels lOf. By means of this. arrangement, the auto- • matic movement of restoration of the steering lever and stopping of the travelling movement, mentioned above, are produced. Below, the patent claims will be presented, whereby the various details of the invention may show variation within the scope of the inventive idea defined by the said claims.

Claims: WHAT IS CLAIMED IS: 1. An arrangement of drive wheels, which is designed for producing the drive force for vehicles, various transfer devices, or equivalent, the said arrangement comprising a combination of a) a construction, such as a frame plate (17), to be rotated around a first shaft (B-B), the said first shaft (B-B) being substantially perpendicular to the plane of the running base (P), b) a motor (15) and a power transmission (I β ), by means of which the said construction (17) is rotated around the said first shaft (B-B), c) a set of wheels (10), whose wheels (lOailObjlOc.lOa 1 , 10b',10c') are turnably connected to the said first construction (17) by means of articulated shafts (12, 18) or equivalent, d) a first steering mecchanism (21; 27, 28), by means of which the wheels of the said set of wheels (10) are guided to run., duri-ng rotation of the said first construction (17), along such tracks (r , r. , r ) that the axis lines (L) of the wheels (10) intersect each other substantially on the same straight line or substantially at the same point (A), e) a second steering mechanism (22, 23, 24), which is coupled to the said first steering mechanism (21; 27, 28) so that the line or point of intersection (A) of the axis lines (L) of the wheels in the set of wheels (10) can be deviated in relation to the axis of rotation (B-B) of the said first construction (17) so as to produce a drive force and a- tractive move¬ ment by means of rotation of the said first con¬ struction (17) while the wheels of the set of wheels (10) are in contact with the running base (P), c h a r a c t e r i z e d in that the said second steering mechanism (22, 23, 24) includes a steering lever (22) mounted to the frame (13) of the equipment by means of a universal ball joint (23) or equivalent and __ • • ___ fitted so that by means of the said one steering lever (22) it is possible to deviate the line or point of intersection (A) of the axis lines (L) of the wheels of the set of wheels arbitrarily so that both the direction of drive and the speed of travel of the equipment can be selected steplessly and freely by means of one selection of the position of the said steering lever. 2. An arrangement of drive wheels as claimed in claim 1, c h a r a c t e r i z e d in that the steering lever (22) is a two-arm steering lever, which is at the lower end coupled to the first steering mecha¬ nism. 3. An arrangement of drive wheels as claimed in claim 2, c h a r a c t e r i z e d in that the • steering lever (22) is in its free position positioned substantially vertically. 4. An arrangement of drive wheels as claimed in claim 1, 2 or 3, wherein the said first steering mechanism comprises a steering linkage (21), one end of the various rods of the said linkage being connected to the forks (19) or equivalent of the wheels (10a, 10b, 10c) of the wheel set, mounted to the first construction (17), and the other ends of the rods being connected to the second steering linkage, e.g. to the steering lever (22), by means of which lever the interconnected ends of the said linkage (21) can be together deviated in relation to shaft of rotation (B-B) of the first construction so as to produce tractive movement and drive force, c h a r ¬ a c t e r i z e d in that the inner ends of the steering rods (21) are connected to the lower end of the steering lever (22) underneath the said universal ball joint (23) or equivalent. 5. An arrangement of drive wheels as. claimed in claim 1, 2 or 3, c h a r a c t e r i z e d in that the wheels (lOe) of the wheel set (10) are connected to a telescope construction (27, 28) the inner ends of whose rods are connected to each other and to the steering _OKf?I mechanism so that the telescope construction can be extended and shortened while the wheels (lOe) of the wheel set roll along their specified tracks (r , r, , r ) as rotated by the first construction (17). 6. An arrangement of drive wheels as claimed in claim 1, 2, 3, 4 or 5, c h a r a c t e r i z e d in that, as fastened to the same first construction, such as frame plate (17), the apparatus comprises two or more sets of wheels (10a,10b,10c and 10a',10b',10c' ), whose axis lines (L) are controlled so that, when the first construction (17) revolves, they intersect each other substantially at the same point (A) or on the same line. 7. A transfer device as claimed in claim 1 J 2, 3, 4, 5 or 6, c h a r a c t e r i z e d in that two or more arrangements of drive wheels have been fitted to the frame (13) of the transfer device as jointly operative. 8. A transfer device as claimed in claim 1. 2, 3, 4, 5, 6 or 7, c h a r a c t e r i z e d in that, besides one or several arrangements of drive wheels, the transfer device includes one or several wheels (11a, lib) of fixed direction of rotation. O PI

Inventors: FAGERSTEDT N
Applicants: FAGERSTEDT N, FINVENTORS A
Application year: 1981
Main classification: B62D15
IPC codes: B62D15