The invention concerns a conveyor of the type defined in the introductory portion of claim 1.

Such a conveyor is known from the Danish Patent Applica¬ tion 0442/88.

In this known conveyor the lifting means consist of ro- tatable links which connect a rail and a rod-shaped means to provide a parallelogram. The actual lifting movement of heavy objects by lifting of the rod-shaped means upwardly above the edges of the opening in the U-shaped stationary means therefore takes place with a rather short displace¬ ment of the rod-shaped means in the longitudinal direc¬ tion, and the gear ratio in the lifting movement is there¬ fore not very great.

The object of the invention is to provide a conveyor of the type stated in the opening paragraph which has a greater gear ratio during the lifting movement, so that this requires fewer forces than in the above-mentioned known conveyor. This object is achieved according to the invention in that the present conveyor is characterized by the features defined in the characterized portion of claim 1.

The lifting movement will hereby take place with a great gear ratio since the disc rolls on the inclined faces. As mentioned, the inclined faces are preferably parallel so that pure rolling of the disc will be obtained. If they are not parallel, or if there is perhaps just one inclined face in the bottom of one U-shaped rail, the disc will be liable to slide, which counteracts the lifting movement.

The invention will be described more fully below with re¬ ference to the drawing, in which

fig. 1 is a perspective view of a section of a conveyor according to the invention, with parts removed,

fig. 2 is a schematic and lateral view of the same con¬ veyor in a position where the upper edge of the upper rail is lifted upwardly above the edges of the opening in the U-shaped stationary means,

fig. 3 shows a section along the line III-III in fig. 2, and

fig. 4 shows schematically and in perspective how several parallel conveyors according to the invention can coope¬ rate for transporting a single large and optionally parti¬ cularly heavy object.

The conveyor shown in the drawing comprises a cross- sectionally U-shaped means 1 whose opening faces upwardly.

The means 1 contains two cross-sectionally U-shaped rails 2, 3 which are arranged over each other and whose openings face each other. The lower rail 2 and the upper rail 3 can be reciprocated as a unit in the U-shaped means 1 by means of a motion mechanism in the form of a handle 4 arranged on one end of the rails 2, 3, which protrude beyond the U- shaped means 1, and which are shown partly in the drawing. Further, the rails 2 and 3 may be displaced longitudinally with respect to each other by turning the handle 4 to the position shown in broken lines in fig. 1.

When the rails 2 and 3 are displaced mutually in one di- rection (to the direction shown with broken lines in fig. 1 and with solid lines in fig. 2 for the rail 3), the

upper edge of the rail 3 will be lifted upwardly above the edges of the u-shaped stationary means 1 by lifting means.

These lifting means consist of bodies 5 and 6, respective- ly, which are secured in the interior of each rail 2, 3, and which are preferably shaped uniformly and have in¬ clined faces 7, 8 and 9, 10, respectively. These inclined faces 7, 8 and 9, 10 meet in pairs in the form of a V, and the V-shaped inclined faces of the bodies face each other and surround a loosely arranged circular disc 11.

In fig. 1 the disc 11 and the bodies 5, 6 are shown in the mutual position in which the upper edge of the upper rail 3 is lowered below the edges of the opening in the U- shaped stationary means 1.

In fig. 2 the rails 2, 3 and thereby also the bodies 5, 6 are shown in the mutually displaced position provided by means of the handle 4, whereby the disc 11, as shown, has moved by pure rolling along the inclined faces 7 and 10 so that the upper edge of the rail 3 is lifted upwardly above the opening in the U-shaped stationary means 1.

As mentioned, fig. 1 just shows a small part of the right end of the conveyor. The U-shaped stationary means 1 and the rails 5, 6 continue in elongation of this to the left, just as additional lifting means 5 to 11 (not shown) are provided with regular, suitable intervals between the rails 2 and 3.

The bodies 5 and 6 can quite simply be secured to their respective rails 2 and 3 by means of a small pin 12 and 13, respectively.

The pins 13 in the lower rail 2 may suitably protrude beyond the rail 2 to form shafts for mounting wheels 14,

which reduce the friction in the movement of the rails 2, 3 as a unit in the U-shaped stationary means 1.

As shown, the handle 4 suitably has a slot 15 to provide the necessary freedom of movement in the mutual displace¬ ment and lifting of the rails 2, 3.

It appears from fig. 4 how a plurality of parallel trans¬ port means 20 may be used for jointly transporting a large object 21.

Then, the handles of the individual conveyors 20 are to be coupled together (not shown), so that the conveyors 20 work in synchronism.