Wheel assembly.

The invention relates to an impeller for overcoming obstacles that protrude from the pavement upward as particular steps, thresholds etc ..

The wheel, one of the oldest and most widely used machine elements, also known to be used only there safely, where an appropriately leveled road is available. Once the road has barriers, which protrude from the pavement up and wheel diameter have a specific height relative to be reckoned with considerable difficulty getting.

Such obstacles as stairs, thresholds, sidewalk paragraphs etc. are, however, very frequently found both within our residential and industrial buildings, as well as on public roads and paths. To achieve their conquest, for example, was already proposed to replace the normally wheeled handcarts each of the two wheels by a rotatable star-shaped combination of three rollers. In each case, the upper of the three rollers is situated above the central region of the two lower who have contact with the road. When encountering an obstacle, such as a stair step, first comes up against the bottom front roller and serves as a stop or rotational axis when pulling up the sack trolley. The upper roller arrives at the next higher step. When using this known device is noticeable that pulling up the sack trolley considerable force requires what can be explained in large part by the fact that the assembled with three casters wheel center to overcome each stage by 120⁰ must be rotated and is not involved in at the upward movement of the sack trolley. Also, in using these known wheels difficult, often impossible to overcome stairs, which do not have vertical end walls between the individual steps.

It is therefore an object of the present invention to provide an impeller for overcoming obstacles, the convenient handling and minimal force allows for increased safety and is to overcome many obstacles, including stairs without vertical end walls, is suitable.

This object is achieved by the method defined in claim 1 characteristic combination. Preferred embodiments result from the dependent claims.

<ul><li>Fig. 1 is a simplified side view of one embodiment of the inventive impeller;</li><li>Figs. 2 and 3 illustrate drive options with reference to schematic side views;</li><li>Fig. 4 shows such an impeller in a perspective view.</li><li>Fig. 5 is a perspective view of a variant of the supporting roller bearing;</li><li>FIGS. 6 to 9 are schematically simplified side views of the wheel in four different phases during climbing a staircase step and the</li><li>FIGS. 10 and 11 schematically show a four-wheel variant.</li></ul>

FIG. 1 shows a trolley 1, as used for example by Kaminfegern for cleaning boilers. Since the boilers are mostly in the basements or cellars, several times on stairs must be moved up on and such a car daily. The handling of the car on stairs is still made particularly difficult that the same given the accommodated in him equipment and Absaugeapparatur has a considerable weight.

The frame 1 has a frame 2, two fixed handles on the upper part 3 and four wheels. The two impellers designated 4 in accordance with the known type and are preferably rubber wheels. The other, designated by 5 two wheels, however, are specific to the overcoming of obstacles, in particular stairs, designed and are described in terms of their design, and their function below.

According to FIG. 4 are connected to a main axis 6, which in turn is rotatably mounted on the underside of the frame 2, two rotary star pairs 7 is fixed by means of a nut 8 which is screwed onto a threaded part 6a of the main axle 6. Each star wheel 7 is the shape of the Star of David according fünfstrahlig and has at each of its radial arms a radial slot 9. In the slits of the two arranged at a mutual spacing on the major axis 6 of rotation star 7 rollers 10 are inserted from the outside with their axes 10a and secured by wing nuts eleventh The rollers 10 can be inserted so far in the direction of the major axis 6 inwardly thus on the one hand, until they impinge on the ends of the slots. 9 but according to need, the rollers can also in any intermediate position, ie. at a greater distance from the main axis 6, to be locked by means of wing nuts 11

The function of the described wheel 5 at overcome a stair step, FIGS. 6 to 9, which illustrate various temporally successive phases. According to FIG. 6 is the pair of wheels 5 on the lower step of a stair step. To move up the car the stairs, attacking the main axis 6 to a force P, which may be due, for example, of a carriage on the handle 3 withdrawing person. Other drive modes are possible and are then be discussed.

. Referring to Figure 6, the mass r and a must be chosen so that 2r + a&gt; H&gt; r + a in the FIG. 1 starting position shown extends the axial center of the upper roller L₀ consequently to a measure b on the edge of the upper stage 13. Under the influence of the force P overcomes the top roller L₀ Thus, the step edge K, while the lower roller is raised by a distance d (Fig. 7) The vertical axis of the wheel 5 is pivoted about the angle a rearwards.

Upon further exposure to the tensile force P now enters the top roller L_O on the upper step 13, wherein the wheel axis A by an angle β now tilts forward and the lower running roller L_u rests against the vertical end surface of the stair step. Subsequently, then passes the lower roller on the upper level and the described cycle is repeated.

Thanks to the mutual association of the upper and lower roller, the overcoming of stairs and similar obstacles is greatly facilitated, since the load. one hand still during a large part of the first lifting phase (Fig. 7) is supported on the lower level 12 and the other part at the first action of the tensile force P, the lifting of the lower impeller has a favorable influence on the force ratios. Since the top roller L rests relatively early on the stair nosing K, the lower roller L '_u (Fig. 7) relieved. It is also a great advantage that the required when climbing the stage tilting extends relatively small angle a with respect to the known three-star wheel.

Another advantage of the construction described is shown in FIG. 9. Does the stairs namely, as is the case with numerous stairways, basement stairs and floor stairs, not the levels 12 and 13 connecting the end wall, so the wheel becomes still without any difficulty go up the stairs , It is only the pivot angle a (Fig: 7) is slightly larger, as the untere.Laufrolle L protrudes into the intermediate space between the two stages 12/13. At a certain altitude is the lower roller L_u However, at the lower edge of the step K '(Fig. 9) and the impeller 5 can be in turn, as described, pull up.

In addition to pulling the device by hand of course also motor drives in question. For this purpose, the main axis 6 (Fig. 2) coupled to a motor and a sprocket 15, a chain 16 and another sprocket 17 may be connected to the running rollers 10. Also, the torque transmission, as FIG. 3 shows, carried by gears 19 which are rotationally rigidly connected to the roller axles 10a and intermesh with a central, seated on the main shaft 6 drive pinion. The examples of the torque transmission can be further extended by the skilled person within the scope of the invention.

As the amount of to be overcome obstacles is not always the same, the adaptability of the rollers 10 is of some importance. An adjustment has been described with reference to FIG. 4 (wing nut). In order to keep the axis 10a of the rollers even safer and to prevent their radial slipping under load, in the slot 9, a bearing 22 may be disposed radially displaced so that it can be fixed in any radial position by known means.

The wheel can be described for a variety of means of transportation, such as hand trucks, wheelchairs, strollers, carts, etc. Post and quite generally all running on wheels car, have to overcome the obstacles in the form of stairs, doorsills etc..

In all cases, is such as ersicht from FIG. 6 Lich, the radius r and the distance A (FIG. 6) selected so that the running roller L with its lower half is incident on the edge K.

The inventive idea can also be applied to an impeller having four disposed on a common circular arc at the same distance wheels. By the pulling force P is the castor L_O raised to the level 13, and then is supported on the stage 13 similarly as described in the impeller with five rollers.

The desired effect, overcome with geringem.Kraftaufwand and increased levels of security, can be realized only with four or five wheels per wheel, wherein the variant with 5 rolls is given preference.

To improve ride comfort in a plain path, for example, a be provided from the handle 3 of operable mechanism by which a ground contacting rollers can be lifted off the ground. This mechanism can eg act on a roller shaft 10a and permits the reduction of rolling resistance, which is in particular advantageous effect in curves.