The present invention is related to masts of trucks of the kind where a couple of load forks are journaled for a lifting movement in a so called mono-mast, that is a centrally placed column-like mast. Such a truck with accompanying mast is for instance known from DE 196 18 246 Al, where the mast comprise two opposed U-shaped beams between which a roller bracket is arranged moveable in the height direction. The roller bracket is journaled with rollers in the U-shaped beams. The roller bracket extends on the front side of the mast (fork side) out between the U-beams and is fastened in a fork-yoke or the like supporting the forks. On the opposite side of the U-beams (driver's side), a lift cylinder is arranged outside of the beams connected with the roller bracket via a chain transmission gearing up its stroke. The vertical beams are arranged close to each other but with sufficient space between them to accommodate the forward and rearward protruding roller bracket.

A drawback at this kind of truck is however that the mast end up precisely in the middle of the field of vision of the truck driver when the truck is driven with the forks first, which -negatively influence the supervision as -well as precision and result in the driver haying to move himself laterally in order to see past the mast. It is thus desirable with a mast that in a lateral direction of the truck is as thin as possible. However the vision problem occur also at turning and not least at sharp turning when the driver is more or less at the side of the truck. Nor is the problem lessened by this type of trucks being frequently used inside for instance superstores during opening hours, that is in the presence of customers that sometimes can be numerous.

A solution to this problem could be to place the mast off center, for instance in one of the front corners instead of centrally. Certainly this will improve the vision straight forward but it still means the same loss of vision and even a larger loss of vision when the driver turns sharply and is on the mast side. Besides the mast is once again an obstacle on one side of the truck.

In view of the above problem the object of the invention is to provide a mono-mast that is more compact than the previously known ones so that it reduces the field of vision less. The above object is in accordance with the invention at a mast of the above described type (mono-mast) solved by the roller bracket on the side facing away from the forks being

provided with a longitudinal recess so that the roller bracket receives a more or less U- or V-shaped cross section. The lift cylinder is arranged entirely or partly between the two beams on the side of the beams facing away from the forks and the recess in the rear side of the roller bracket allow this to pass in front of and on the sides of the lifting cylinder and its piston rod so that the two U-shaped beams can be located close to each other despite the lift cylinder being located between these.

The roller bracket is advantageously fastened to the crosswise extending fork yoke by welding. By shaping the roller bracket with a nose protruding precisely above the fork yoke the length of the weld joint is increased, which considerably increase the strength in an otherwise susceptible place. Furthermore in this way ^' an unbroken weld line is obtained all the way around which also reduce the risk of cracks and fractures and furthermore the roller bracket is strengthened in this way.

The mast in accordance with the invention becomes, as is realized very compact to its cross section with a considerable improvement of the vision field from the side and thus improved safety and precision.

-Further characteristics of the invention appear- from the patent claims -and- from the following description of a preferred embodiment of the invention with reference to the enclosed drawings. At this fig 1 shows a truck in accordance with the invention in perspective, fig 2a - c a roller bracket in perspective and in section, fig 3 a cross section through the mast and fig 4 a perspective view of the upper end of the mast with one beam and lid removed for the sake of clarity and with the forks and roller bracket in the topmost position.

As apparent from fig 3 the mast shown in its entirety in fig 1 includes two each other facing U-beams 2. In the beams rollers ran that are constituted of spherical roller bearings 3. The spherical roller bearings are arranged on laterally extending dowels 4 on a roller bracket 5. The roller bracket is on its rear side, that is the side facing away from the forks, provided with an eleongate recess 14 so shaped that a space is shaped between U-beams 2 and roller bracket 5 that is sufficient to receive with a certain play a lift cylinder 6 inside the contour described by the outer sides of the U-shaped beams. With a comparatively large dowel diameter and a material with a good strength, for instance dropforged steel or cast steel a sufficient strength can be obtained despite the recess for the lift cylinder 6 extending almost

to the rear edge of the dowels 4. The U-shaped beams may actually be placed so close to each other that the lift cylinder at mounting has to be pushed in from the upper fork end of the beams. The recess in the roller bracket has the shape of a cylinder surface in order to adapt, with an intermediate play, to the outer shape of the lift cylinder. In the roller bracket a chain 7 is fastened that run up over a chain pulley 8 arranged in the upper end of a piston rod 9 belonging to the lift cylinder 6. The chain is fastened on the opposite side to the forks in the mast and when the piston rod is lifted up the measure with which the chain lifts the forks will be the double of the piston lift in a known manner.

The chain 7 is, as is apparent from figs 2 and 4, fastened with a pin in a bolt hole 11 bellow the middle of the roller bracket in this and a further recess 12 is arranged in the roller bracket for the chain extending down to the chain fastening 11 so that the roller bracket in its upper end receives an almost V-shaped cross section. In this way the roller bracket in the upper end of the fork lift can pass up above the chain pulley 8 in the upper end of the piston rod 9 so that the entire mast height can be used. In the shown embodiment the width of the roller bracket essentially corresponds to the width of the cylinder.

The U-beams are in the upper -end,- for mounting and dismantling, connected via ^* a removeable lid 13. On the rear side (drivers side) of the mast the U-beams may be connected with each other by short tie struts or webs. In this way the stiffness of the mast against twisting and lateral bending respectively is increased. The opening on the rear side between the beams is furthermore closed by a cover.

Since it in accordance with the invention is possible to place the lift cylinder entirely in the space inside the outer contour of the beams an extremely compact mast is obtained, which greatly improves visibility for the driver.