Background of the invention

The invention relates to a bearing wheel arrangements of a low and nor mally suspended hoist for supporting the hoist on a running platform and for mov- ing the hoist on the running platform; whereby the bearing wheel arrangement comprises, in the direction of movement of the hoist, on opposite sides thereof always at least two bearing wheels arranged on the frame of the hoist.

lt is known that low and normally suspended hoists (trolleys) are sus pended on main girders by bearing wheels which are at the ends of an axle fastened to the frame of the hoist. These days, there exists a plurality of hoist bodies depend ing on the hoist type or, for example, the length of a rope drum installed on it. The problem is that it is not cost effective to manufacture a plurality of different frame variations for a hoist ln addition, in the present solutions the alignment under load of bearing wheels easily changes, and they are subjected to dust. Summary of the invention

lt is thus an object of the invention to develop a new type of bearing wheel arrangement of a hoist so as to solve the above-mentioned problems. This object is achieved by the bearing wheel arrangement of the invention, which is characterised in that the bearing wheels on the same side of the hoist are at any one time arranged on the same suspension part which is fastened to the hoist frame.

When the bearing wheels are fixed to the same suspension part, the mu tual alignment of the wheels remains precise. The alignment also remains precise under load contrary to the present solutions, because now the point of contact of the bearing wheels on the main girder may be arranged on a neutral axle of the supporting frame structure.

Each bearing wheel is advantageously supported to the suspension part at two supports points on both sides of the bearing wheel. The two-sided supports allows a smaller axle diameter of the bearing wheel.

At the same time, the bearing wheels and suspension parts may be formed as bearing wheel modules that are detachably fastened to the hoist frame lf the suspension part is in such a case advantageously formed of a pipe profile, in which openings and suspension cutouts have been made for the protrusion and fastening of the bearing wheels, the protection of the bearing wheels against dust is effective. Such an enclosure also forms a fracture support for a bearing of the bearing wheel without a separate protection.

With the solution according to the invention, it is possible to set up a dedicated module independent of the hoist frame, having boundary surfaces to other required components and which may be assembled separate from the hoist frame ln a most advantageous manner, the invention may be adapted in a low- construction hoist in which vertical height limitations set more demanding design challenges on the hoist.

At the same time, the bearing wheel arrangement of the invention makes the hoist frame simpler and more modular as a whole. Due to the modular structure, in a servicing situation the entire module may be replaced or it may be separated whereby the bearing wheels, their axles or bearings may be separately replaced. Detaching the module makes it possible to carry out servicing on the bearing wheels, or to replace parts associated with it, at ground level or in a work shop, for example.

Other parts, too, are adapted in the modular bearing wheel enclosure, by means of which power transmission may be conveyed between the wheels ln other words, a module replacement in a servicing situation also amends and re pairs parts of the power transmission, if so desired. The power transmission parts may transmit power from one wheel to another in the longitudinal direction of the module, or with the aid of an auxiliary shaft, in a parallel fashion from one module to another. The components in the power transmission of the module have advan tageously been correctly aligned at the assembly stage of the module, and this is facilitated by the fact that it has been possible to make the precise machining of the module to form the division surfaces with the same machining fastening. lf it is desired to replace parts of the power transmission one by one, that is possible, too, due to the precise machining referred to in the above.

The bearing wheels may advantageously be fastened to the bearing wheel module by a double-shear axle, that is, fork suspension may be used. This improves the alignment of the wheels also when the hoist is under load lt is known that the frame of the hoist twists when the hoist is hoisting, and the rising of some wheels off the supporting support surface, such as an 1 beam.

The machining made on the bearing wheel module may be made on both walls at the same parallel spots, such as drillings and threaded holes. The walls may be symmetric. When an axle beam of the bearing wheels passes both walls of the bear ing wheel module, the holes it requires are simple to machine orthogonally, and the loading is exerted on both walls of the enclosure during a hoisting operation. The axle may be of a rod or pipe.

List of figures

The invention will now be explained in more detail with reference to the accompanying drawings, in which

Figure 1 is a hoist, as seen from an end, which has the bearing wheel arrangement of the invention;

Figure 2 is a top view of the inventive hoist;

Figure 3 is a side view of the inventive bearing wheel module having the operational equipment of the bearing wheel;

Figure 4 is a top view of the bearing wheel module of Figure 3;

Figure 5 shows one bearing wheel shown in Figures 4 and 5 in the cross section A - A of Figure 4;

Figure 6 is an exploded view of the bearing wheel module seen in Fig ures 4 to 6;

Figures 7 to 11 show different ways to use the bearing wheel/wheels with a driving mechanism;

Figures 12 and 13 show fastening means of the bearing wheel module to a hoist.

Detailed description of the invention

Referring first to Figures 1 and 2, in them are only shown a frame 2 of a hoist 1 and a bearing wheel arrangement 3a, 3b of the hoist for supporting the hoist 1 on a running platform and for moving the hoist 1 on the running platform. Also shown is the operational equipment associated with one bearing wheel arrange ment 3a, to be described below. The other components of the hoist 1 are, insofar as the invention is concerned, irrelevant. A running platform refers for the most part to the main girder of the hoist 1, which has rail structures (not shown) for the bear ing wheel arrangement 3a, 3b. ln addition, the structure of the running platform or main girder, in particular in case of a straight track, has no essential importance from the point of view of this invention.

The bearing wheel arrangement 3a, 3b here comprises, in the direction of movement of the hoist 1, on opposite sides of its frame 2 at least two bearing wheels 4,5 and 6, 7 at any one time, arranged on the frame 2 of the hoist. ln accordance with the invention, the bearing wheels 4, 5 and 6, 7 on the same side of the hoist frame 2 are at any one time arranged on the same suspension part 8a, 8b which is fastened to the hoist frame 2.

Each bearing wheel 4 - 7 is supported to its own suspension part 8a, 8b at two support points on both sides of the bearing wheel 4 - 7.

The bearing wheels 4 - 7 and suspension parts 8a, 8b are formed into bearing wheel modules 3a, 3b which are detachably fastenable to the frame 2 of the hoist 1.

Both suspension parts 8a, 8b are in this exemplary implementation formed out of a (square) pipe profile, in which openings and cutouts have been made for the protrusion and fastening of the bearing wheels 4 - 7. These are best seen in Figure 6. Both ends of the suspension parts 8a, 8b are provided with end reinforcements 9 and bumpers 10.

ln one bearing wheel module 3a, an operating or moving mechanism is fastened, comprising a motor 11 and transmission 12 for driving at least one bear ing wheel 4 - 7 and thus for moving the hoist on its running platform.

The suspension part 8a, 8b may be a laser-cut RHS tube lt does not re quire any further machining, which means there is one work step less. The material may be structural steel or high-strength steel. Due to the shaping and suitable cut outs, the bearing wheels 4 - 7 are easy to install and, if need be, to replace ln the suspension part 8a, 8b, it is possible to machine only the portions that are needed to fasten the bearing wheels 4 - 7, and to fasten the suspension part 8a, 8b itself to the hoist 1. Therefore the suspension part 8a, 8b is easy to come up with by using conventional RHS profile steel. The amount of machining is little, and the suspen sion part 8a, 8b becomes stiff enough to bear a load. Because the portion above the bearing wheels 4 - 7 is not machined off, it adds to the stiffness of the suspension part and provides a dust cover for the bearing wheels 4 - 7. A suspension part 8a, 8b of a different length may be selected for hoists of different sizes, which in turn is achieved by selecting a suitable length of an RHS beam for machining.

Each bearing wheel 4 - 7 is advantageously made by machining, and comprises two bearings, a rotary-cut axle and locking rings. Each bearing wheel 4 - 7 has a load-bearing periphery supported by which it may move on a running platform. This supporting perimeter of the bearing wheel 4 - 7 extends outside the pipe profile used for the suspension part 8a, 8b. The bearing wheel driven, of which there may be one or more (explained in more detail in connection with Figures 7 to 11) additionally comprises a toothing to drive it. The axle connects to the sus pension part 8a, 8b on both of its ends. The notches needed for the axle are easily created in the machining from an RHS beam so that a precise space for the bearing is made in both walls of the suspension part 8a, 8b with the same machining, which results in a simple and correct alignment of the bearing wheels 4 - 7. ln the same manner, the required holes may be made for parts taking part in power transmis sion, such as an intermediate gear 14 in Figure 8.

The end enforcement 9 is advantageously a laser-cut and bent sheet to which a bumper 10, advantageously made of rubber, is fixed.

The moving mechanism 11, 12 is fixed to one bearing wheel module 3b by means of a precise parking sheet (not shown) at the correct distance and correct position in relation to the toothing on the bearing wheel being driven. This way, the requirements for precision set on the cuts of the bearing wheel module 3b may be lowered.

ln the bearing wheel modules 3a, 3b, the power of the moving mecha nism 11, 12 may be sent to the bearing wheels driven in a plurality of ways ln the following, some of the technical methods of implementation will be described.

Figure 7 shows an implementation that has one driven bearing wheel 4, only, which is in the same bearing wheel module 3a as to which the moving mech anism is fastened ln this case, the toothing 13 of the axle at the end of the drive axle of the transmission 12 is in a direct usage contact with the mating toothing 4a on the perimeter of the bearing wheel 4.

Figures 8 to 11 show implementations where there are two drive wheels, whereby the wheels 4, 5 driven in the solutions of Figures 8 to 10 are lo cated in the same bearing wheel module 3a as to which the moving mechanism is fastened.

ln Figure 8, the toothing 13 of the axle at the end of the drive axle of the transmission 12 is in a direct usage contact with the mating toothing 4a on the pe rimeter of the bearing wheel 4 as in Figure 7, but in addition between the bearing wheels 4 and 5, an intermediate gear 14 has been arranged, which transmits the drive moment also to this bearing wheel 5 by means of a toothing 5a on the perim eter of the bearing wheel 5.

ln Figures 9 and 10. the drive axle of the transmission 12 and the bear ing wheels 4 and 5 are connected each other either with a toothed belt or V belt 15, in which case a tensioning reel 16 has been arranged between the bearing wheels 4 and 5. ln Figure 11, the driven bearing wheels 4 and 6 are located in different bearing wheel modules 3b and 3a. ln this case, the toothing 13 of the axle at the end of the drive axle of the transmission 12 is in a direct usage contact with the mating toothing 4a on the perimeter of the bearing wheel 4 like in Figures 7 and 8, but in addition there is arranged, between the bearing wheel 4 and bearing wheel 6 in the bearing wheel module 3a on the opposite side, a drive axle 17 to drive the bearing wheel 6, too.

lf it is desired that all the bearing wheels 4 - 7 are driven, this may be implemented as a combination of the above, and/or, if need be, by using a second moving mechanism installed in the bearing wheel module 3b

The bearing wheel arrangement of the invention makes it simple to im plement different kinds of drive methods, as has been shown in the above.

Figures 12 and 13 show how the bearing wheel modules 3a, 3b may be fastened to the hoist frame by C-shaped clamps or subassemblies 18, for example. A solution planned like this, an axle passing through the wheel enclosure pipe as well as a plate or RHS tubes. However, the fastening may be implemented by nu merous other ways. Essential for the invention are the actual suspension parts 8a, 8b and bearing wheel modules 3a, 3b formed by the bearing wheels 4 - 7. A natural way to form the bearing wheel module 3a, 3b is to use a closed profile, such as an RHS beam, but the same outcome may also be reached by a machining technique of a plate, resulting in a bent C profile which is open at the bottom. The open direction of the C profile is thus in the direction of the running platform of the hoist, so down ward.

The above description of the invention is only intended to illustrate the basic idea of the invention. A person skilled in the art may, however, implement its details within the scope of the attached claims.