WO1995006582A1

WO1995006582A1 - Ground engaging conveying device

Info

Publication number: WO1995006582A1
Application number: PCT/SE1994/000789
Authority: WO
Inventors: Göran ROOS
Original assignee: Roos Goeran
Priority date: 1993-08-31
Filing date: 1994-08-30
Publication date: 1995-03-09
Also published as: AU7626894A; SE9302804D0; SE9302804L

Abstract

Wheels are utilized to effect movement of trolleys, wheelbarrows and the like, a greater force being required if they are to surmount a hinder. The object of this invention is to reduce the force required by replacing a wheel with a unit rotatable about an axle, a number of parts being arranged one after the other outside said unit, said parts being externally flat and rectangular, the part which is in contact with the ground surface remaining stationary during rotation of the unit, until the part in front of it comes into contact with the ground surface.

Description

Groundengagjug conveying device.

The invention relates to the ingress of the Patent Application.

The condition required for the wheel to perform satbfactorily is a hard and smooth surface. Under circumstanses where these requirement are not complied with, the negative properties will appear. The following three are considered to be the most salient ones:

- It follows every irregularity of the surface, both bumps and ruts. This is causing anunsmoothride and also a loss of energy.

- Its shape implies a small contact area.This feature makes it unsuitable for use on soft and fragile grounds, since it causes permanent deformation of the surface. Hence, it will also require a high propulsion power.

- The explanatory sketch, Fig. 5, shows, with a continous line, how the centre of the wheel moves when passing over an obstacle. The angle V between the ground plane and the moving line of hub centre is fairly big thus the wheel requires a high momentary force with the start of ascent In order to avoid a too high vertical acceleration when passing over an obstacle the speed must be kept low.

Among some of the measures taken to reduce the above mentioned negative properties of the wheel can be mentioned:

- Complicated suspension system, wide tires and low air pressure, big diametres, etc. All of the above mentioned measures make the vehicle heavier and more expensive to produce. It will also make it require more propulsion power. The latter is a disadvantage, especially when the vehicle is battery- or human-powered.

The object of my invention is to, within certain fields of application, offer a replacement to the wheel which, without the need of expensive suspension system, provides a soft ride, has a low propulsion power requirement and an even distribution of the load on the ground. A further object is to offer a device which passability is not proportionally dependant of the diameter, as is the case with the wheel, and which can be used on soft and irregular surfaces in comparatively small sizes.

The above mentioned features are possible to achive through the vertical lowering of two groundengaging supporting pads and that the load, via the cross-links, is moved over these two points. The principles of the movement are similar to that of a walking person or an animal.

According to the same principles and, as can be understood from Fig. 5 broken line, the angle "β" between the hub centre line of movement, and the horizontal level, when passing an obstacle, is considerably smaller than the one for a wheel with the same centre bight

This implies that the power requirement at the initial part of the passing of an obstacle is about 60 per cent less, and that the obstacle can be passed at greater speed. Thus the kinetic energy does not need to be lost through the braking of the vehicle, but can instead be utilized for the passing.

The principles of funktion of the unit also make possible the ^corporation of a telemetry and level-ccmpensating unit which, within certain limits, automatically adjusts the height of the groundengaging pads before reaching the ground contacting position. By compensating for unevenesses on the ground, it is possible to further decrease the vertical movement of the hub.

One type of the invention is shown on the enclosed drawings.

Accenting to Fig. 1 the invention consists of one hub (1) provided with a centre shaft and 8 nos. of link-journals, 8 nos. cross-links (2), mounted in pairs, 4 nos. of ground- engaging links (3), 4 cam rollers (4) mounted on the cross-links and finally two cam discs (5) mounted on the vehicle frame.

With the purpose to interconnect the two pairs of cross-links, diametrically mounted on the same side of the hub, the big end of the cross-links pivoted in the hub are provided with gear teeth, or some other type of mechanism for transfer of the movements. Each groundengaging link with the connected pair of the cross-links supports the load of the vehicle during 90 degrees of the rotation of the hub. This means that the load is transferred from the L.H. side to the R.H. side pair of cross-links and vice versa four times during one full revolution. h order to make clear the position of the details included in the device, Fig. 6 shows the hub with only one pair of cross-links installed and the positions of the cam discs. Fig. 2 shows the movement of the hub's centre during 90+35 degrees of rotation with only one pair of cross-links installed. The measure "z" corresponds to the lifting of the groundengaging link.

The table on page 4 shows the changes of position vertically and horizontally of the hub's centre as a function of its rotation from 0 to 45+35 degrees. The possibilities to combine the relative measurement of the cross-links, ground- engaging links and the hub, with a satisfactory result are next to unlimited. The combination of the measurements used for the calculations and which are shown on the table are not claimed to be the optimal. According to the same table, left part, the centre of the hub mflintfling only with very small deviations, the same level when turning from 0 to 45 degrees. Just before the turning reaches 45 degrees, the centres line of movement starts bending downwards slightly. If the rotation continues, the bending of the line increases progressively and at a further 35 degrees of rotation, the lowering of the hub's centre corresponds to 10,7 nxm. When all four pairs of cross-links are installed on the hub, the centre will maintain an almost constant hight above the ground during the rotation.

At the end of each 90 degrees of rotation of the hub the load is shifted from one pair of cross-link to the next pair, mounted on the opposite side of the hub. As the rotating continues, the unloaded groundengaging link is lifted from the ground. At a further 35 degrees of rotation, the lifting height amounts to 10,7 nun.

According to the same table, page 4, right part, the horizontal movement of the centre at 0 to 45 degrees of rotation amounts to 51,3 nun. Consequently, one complete revolution of the hub corresponds to a total linear movement of approximately 410 m,m Fig. 1 shows the device in a position where the tώifting of the load from the R.H. side to the L-H. side of the groundengaging link takes place. In this position the overlap between the shafts of the groundengaging links is "r" nun. This measurement is dependant on the geometry of the device and can not be varied. The total overlap V, on the other hand; can be chosen according to the field of application. The same also applies to the shape, width and properties of the groundengaging links and the cross¬ links.

As earlier mentioned, the movement of one pair of cross-links is transmitted to the diametrically opposed mounted pair on the same side of the hub. When the hub is rotated the interconnection serves the purpose of advancing the lifted groundengaging link (3) to a position where the cam disc (5) controls the lifting of the rear, diametrically opposed, groundengaging link (3) and, at the continuation, the lowering of the advanced front groundengaging link.

Fig. 4 shows the device in a position where the last phase of the lowering is about to begin.

The cam disc (5) mounted on the chassis unit can be divided in three parts. According to Fig. 3 the part "u" controls the lifting of the rear groundengaging link, the part "t" maintains a fixed position of the links in relation to the hub and part V controls the lowering.

With cam discs of different shape and through the installation of additional cam rollers the link movements can be controlled during a greater part of the rotation. Propulsion through the hub centre shaft is possible. The change in position of the centre of the hub as a function of a turn of " " degrees can be seen in Figure 7 where a=10.0 mm, b=128,6 mm, c=165.7 mm, d= 165.7 mm, e=128.6 mm, and the table below.

0 39.095005 114.492 - - -

5 36.662071 114.505 + 0.013 5.436 5.436

10 34.362568 114.539 + 0.047 10.896 5.460

15 32.194422 114.585 + 0.093 16.402 5.506

20 30.154295 114.625 + 0.133 21.975 5.573

25 28.237736 114.635 + 0.143 27.631 5.656

30 26.439379 114.588 + 0.096 33.383 5.752

35 24.753160 114.453 0.039 39.240 5.857

40 23.172530 114.195 - 0.297 45.203 5.963

45 21.690665 113.780 - 0.712 51.271 6.068

50 20.300643 113.174 - 1.318 - -

55 18.995595 112.342 - 2.150 - -

60 17.768829 111-253 - 3.239 - -

65 16.613912 109.879 - 4.613 - -

70 15.524735 108.193 - 6.299 - -

75 14.495553 106.173 - 8.319 - -

80 13.520997 103.801 _ 10.691 _

Claims

1. A unit rotatable about an axle, the rotation being free or driven, said unit being intended to replace a wheel or a rotating cylinder, characterised in that a number of parts are arranged one after the other around the axle and outside the unit, said parts being externally flat, preferably rectangular and each being jointed at or close to its ends to a rodlike link of preferably the same length, the other end of which is journalled in the unit and cooperates with other rodlike links in such a way that upon rotation of the unit one part remains stationary in a predetermined plane until a part in front of it reaches substantially the same plane.

2. A unit rotatable about an axle as claimed in claim 1, where the number of parts at the periphery of the unit is four, characterised in tha the unit is in the form of a tetragon, wherein the inner ends of the rodlike links to one part are hinged, one to each of two corners of the unit located diagonally opposite, the two links thus crossing each other.

3. A unit rotatable about an axle as claimed in claim 2, characterised in that the links of two parts are connected to the same corner in the tetragon and that the links of the other two parts are connected to the remaining corners of the tetragon.