Chassis on wheels

The present invention relates to a chassis on wheels, preferably for use at wheel chairs and industrial robots.

There are several kinds of electrically propelled wheel chairs and industrial robots. Characterizing for most of them are heavy weights and as a conse¬ quence from that, proportionately power consuming electrical engines are necessary. Of course the weight will give a good stability and a good grip for the driving-wheels on an smooth surface, but the movabiiity will be very much restricted.

The ground price for self-propelled wheel chairs is high. In several times the chair need to be adapted/rebuilt to a certain handicap of the intended user of the chair. This may cost more than the standard equipped wheel chair.

The main purpose of the present invention is to produce a light-weight chassis on wheels, which can be driven by low-power engines, has good stability and practicability also on an rough surface, can pass minor obstacles and has a very good manoeuvrability.

An other purpose of the invention is to produce a chassis on wheels where the pressure from the driving wheels towards the ground will encrease when passing an obstacle raising up from the ground.

Yet another purpose of the present invention is to produce a chassis on wheels from few, simple and inexpensive components beeing connected by elastic units to get shoclc absorbing qualities.

Still another object of the invention is to produce a chassis on wheels beeing easily rebuilt and extended.

The above mentioned objects according to this invention are achieved by giving the chassis on wheels the characterizing clauses according to the appending claims.

Having the chassis carried by at least 6 wheels, two of which is driving and arranged in connection to a bogie at a first framework and wherein the second free wheeling pair of wheels at the bogie are principally freely pivoting around vertical shafts arranged at the front end of the framework, ives the chassis a possibility to an effective drive also when passing obstacles. The first framework consists of two principally identical halves beeing connected by transverse stays and elastic units, giving this part of the construction an inherent movabiiity. Said part of the construction and a carriage - having a second framework - connected to the first framework, will make a construction with excellent manoeuvrability since the two wheels of the carriage principally is free to pivot around vertical shafts.

By having the second framework made of two principally identical halves connected by transverse stays and elastic units, also the carriage will have a movabiiity facilitating passing of obstacles when the chassis is moving with the wheels of the carriage directed forward in the moving direction.

By arranging the coupling of the carriage to the first framework in front of and above the centrally placed driving wheels, the carriage will have a very good stability and the pressure force onto the driving wheels will encrease when the rearward paif- of wheels on the carriage will run into an obstacle.

By arranging a chair frame elasticaiiy connected to the second framework, i.e. in the carriage, the carriage will be stabilized without taking the flexibili¬ ty therof away.

Since the driving wheels are centrally placed under the chassis, this have the possibility to rotate around its own vertical and central axis.

The invention will now be described in connection to a shown embodiment under reference to the appended drawings, where

Fig. 1 is a side view of a chassis on wheels according to the invention and where a chair is shematically shown onto the chassis

Fig. 2 is a view from above of the second framework consisting of two halves

Fig. 3 is a view from above of the first framework equipped with two pair of wheels, and where

Fig. 4 is a perspective view from below of the second framework to show the elasticaiiy resilient connection of the two frame-halves with eachother.

In fig. 1 the chassis on wheels 1 is shown consisting of two frameworks 2 and 3. The first framework 2 has two pair of wheels 5a and 5b, and the second framework 3 is hanged onto the first framework 2 at the pivot joint 6 thus forming a carriage with its two wheels 7.

A frame 8 of a chair is - via elastic units 9, 10 and 11 connected to the second framwork 3.

From fig. 2 can be seen - on one hand - how the frame 8 of chair is arranged at the framework 3 through the position of the elastic units and - on the other hand - how the framework consists of two principally identical frame¬ halves 3 a and 3b. The two framehalves have transverse stays 4a and 4b carrying elastic units 14 and 15 - see further fig. 4 - connecting the two halves.

Fig. 3 shows the the first framework 2 and how this framework also consists of two principally identical frame-halves 2a and 2b beeing connected in the same way as the second framework through elastic units. The engines 12 and 13 of the driving wheels 5a preferably have built-in gearings admitting a run with a completely enclosed transmission. At 6 the joint connection between the second frameworke 3 -the carriage- and the first framework 2 is shown.

In fig. 4 is shown how the two framehalves 3 are connected to eachother via the transverse stays 4 and the elastic units 14 and 1 . In connection with the attachment of each transverse stay at the longitudinal frame profile, there is a plate 16,17 and at its end there is a tap 18,19. Between these the elastic units 14 and 15 are positioned. In the figure the two frame-halves have been shown in a stress position where the unit 1 is tensioned and the unit 14 is slightly compressed.

The invention is not restricted to the shown embodiment. Thus, modifica¬ tions can be made within the scoop of the following claims.