The present invention relates to a rotating cab section for a vehicle, said cab section comprising a first floor part and a second floor part being rotatable relative to the first floor part, said first floor part comprising a substantially planar first floor portion, which exhibits a substantially circular opening, and said second floor part comprising a substantially planar and circular second floor portion, which is arranged in the opening of the first floor portion.

In particular, the invention relates to a rotatable driver's position in a counterbalance truck, where the cab floor and the associated driver's seat and control console can be rotated 180° in order to enable forward-facing driving of the counterbalance truck both forwards and in reverse.

SE 358 617 B discloses a revolving driver's position which is supported and driven by a hydraulic revolving motor .

US 2006/0201732 Al discloses a tractor having a rotating cab section. The cab section is arranged on a platform or base plate, which is mounted on a vertical shaft.

WO 01/68400 Al discloses a cab section which is tiltable as well as rotatable by means of control mechanisms. The control mechanism for rotating the cab section acts along the tiltable Z axis of the cab section.

US 6,105,699 A discloses a cab section mounted on a large ball coupling. The ball coupling carries a rotary bearing, whereby the cab section can be rotated. DE 28 49 272 Al discloses a cab section being mounted on a belt-driven rotary mount.

All the above-mentioned known rotating cab sections exhibit the disadvantage that the realization of the rotary function requires a relatively large space in the height direction. This is a problem especially in counterbalance trucks, where a low point of gravity of the vehicle is the aim.

The object of the present invention is to solve this problem and to produce a cab section with a rotating floor part, where the rotary function is realized easily and reliably without occupying a large space in the height direction of the cab section.

The cab section according to the invention is characterized in that the cab section comprises at least three supporting elements, which are arranged in the circumferential direction around the opening of the first floor portion, and which each comprise a rotatable rotary element for direct or indirect interaction with the periphery of the second floor portion, upon which rotary elements the second floor portion is directly, or indirectly, rotatably resting.

In the following, the invention will be described more closely with reference to accompanying drawings.

Figure 1 shows an embodiment of a cab structure according to the invention.

Figure 2 shows the cab structure of Figure 1, wherein the rotatable floor part has been removed.

Figure 3 shows the cab structure of Figure 1 in a view obliquely from below. Figure 4 and 5 show a supporting element in the cab structure of Figure 1.

Figure 6 shows the supporting element of Figure 5 in a cross-section along the section line indicated with VI-VI in Figure 5.

The cab structure according to the invention comprises a first floor part 1, which is fixedly mounted on the vehicle, and a second floor part 2, which is rotatably arranged in the first floor part 1.

The first floor part 1 comprises a substantially planar floor portion 3. Also the second floor part 2 comprises a substantially planar floor portion 4. The floor portions 3 and 4 extend substantially in the same plane, i.e. they are level with each other and have a common normal direction.

The floor portion 4 of the second floor part 2 has a substantially circular shape and is arranged in a corresponding circular opening 6 in the floor portion 3 of the first floor part 1. Only a small slot 5 (see Figure 6) separates the floor portions 3 and 4. The diameter of the floor portion 4 can, for example, be about 950 mm, and the slot can, for example, be about 5 mm.

The top side of the floor portion 4 is adapted to support a not-shown driver's seat. The floor portion 4 exhibits at least one through-opening 7, through which control lines and rods from a not-shown control console and a not-shown pedal assembly, which are mounted on top of the floor portion 4, are adapted to extend. Accordingly, the driver's seat, control console and pedal assembly of the vehicle are adapted to follow the second floor part 2 in its rotational movement.

The floor part 2 comprises a support rim 8 which, in the circumferential direction, extends along the periphery of the floor portion 4 and is attached to the bottom side of the floor portion 4. In the radial direction, the support rim 8 exhibits a first, planar, inner portion 9 (see Figure 6) which forms an abutment surface against the floor portion 4, a second, intermediate portion 10 which connects to the inner portion 9 and angles downward approximately 45° relative to the inner portion 9, and a third, outer portion 11 which is connected to the intermediate portion 10 and angles upward about 90° relative to the intermediate portion 10. Accordingly, the intermediate portion 10 forms an angle α to the plane of the floor portion 4 which is preferably about 135°.

The outer portion 11 and the outer part of the intermediate portion 10 are projecting outside the floor portion 4 and in under the floor portion 3. Accordingly, the support rim 8 prevents an upward movement of the floor portion 4 relative to the floor portion 3.

The cab section also comprises supporting elements 12 for enabling the rotational movement of the floor part 2 relative to the floor part 1. Each of the supporting elements 12 comprise a rotary element in the form a of roller 13, which is rotatably mounted in a bearing housing 14, said bearing housing 14 in its turn being mounted on the bottom side of the floor portion 3. Instead of a roller, a wheel or another type of rotary element can be used. The cab section comprises at least three such supporting elements 12, which are arranged around the opening in the floor portion 3 in which the floor portion 4 is arranged. The supporting elements 12 are so mounted that the rollers 13 extend in under the opening of the floor portion 3 and, thus, also in under the floor portion 4. The rotation axes of the rollers 13 are perpendicular to the tangential direction of the circular floor portion 4 and form an angle β to the plane of the floor portion 4 which is preferably about 160°. Each roller 13, which can be made of metal or a polymer material, for example rubber, is bevelled, so that its shape corresponds to the bottom surfaces of the portions 9 and 10 of the support rim 8 with a good fit. Accordingly, the roller 13 has the shape of two straight truncated cones, the base surfaces of which abut against each other, wherein the cone angles depend on the angle between the rotation axis of the roller 13 and the floor part 2.

The portions 9 and 10 of the support rim 8 are adapted to rest on the rollers 13, and the second, intermediate portion 10 thus forms an angled abutment edge for the rollers 13. In an alternative embodiment (not shown), the floor portion 3 rests directly on the rollers 13, in which case the periphery of the floor portion 3 constitutes an abutment edge for the rollers 13. According to the invention, the supporting elements 12 are thus arranged in the circumferential direction around the opening of the first floor portion 3, for supporting the second floor part 2, wherein the periphery of the floor portion 4 is adapted to rest rotatably, directly or indirectly, on the rollers.

Preferably, the supporting elements 12 are arranged at even intervals in the circumferential direction around the floor portion 4. Accordingly, in case the cab structure comprises three supporting elements, the preferred angular distance between the supporting elements 12 is about 120°. At least one, preferably at least two, and most preferably all of the supporting elements 12 comprise a motor 15 for driving the roller 13 of the supporting element 12. Accordingly, the motor-equipped supporting elements constitute actuators for rotating the floor part 2 relative to the floor part 1. The motor 15 is preferably an electric motor, the rotational direction and speed of which are controlled in a known way by the driver of the vehicle providing appropriate control and regulating signals to the motor 15, via a suitable control and regulating equipment, from his/her position in the driver's cab. Such control and regulating equipments are known per se and will not be described more closely herein.

In that or those supporting elements lacking a motor, the rollers are substantially frictionlessly mounted in their respective bearing housing. Accordingly, the rollers of these supporting elements have the task of supporting the floor part 2 without contributing to the rotational movement .

The driver brings the second floor part 2 to rotate relative to the first floor part 1 in that he/she provides appropriate control and regulating signals to the motors 15 from his/her position in the driver's cab, which control and regulating signals cause the motors 15 to perform a coordinated rotary motion, said rotary motion being converted into a rotational movement of the floor part 2 by means of frictional action between the support rim 8 and the rollers 13 or, in case the floor portion 4 rests directly on the rollers 13 (not shown) , between the floor portion 4 and the rollers 13. In this way, the driver can rotate the second floor part 2 between a first end position, which enables forward- facing driving of the vehicle forwards, and a second end position, which enables forward-facing driving of the vehicle in reverse. Preferably, the floor part 2 can also be adjusted to an optional position between said end positions. Alternatively, the floor part 2 can also be set in one of a number of discrete, predetermined positions between said end positions.

When the floor part 2 has reached its desired position, the internal friction of the motors 15 serves to maintain the floor part 2 in this position. Normally, this internal friction is fully sufficient to ensure that the floor part 2 does not rotate from the desired position. However, the cab structure can comprise a locking device (not shown) being separate from the motors 15, for example in the form of locking means which mechanically lock the floor part 2 to the floor part 1.

The cab structure preferably comprises a positioning system for ensuring correct positioning of the floor part 2 relative to the floor part 1. Such a positioning system can, for example, comprise an optical sensor (not shown) , which is arranged on the floor part 1 for detecting grooves or other marks along the periphery of the floor part 2. The positioning system can alternatively comprise an absolute angle sensor, in the form of potentiometer, which is attached between a non-rotatable part of the cab structure and the bottom side of the floor part 2, at the rotational centre of the floor part 2.

As has been mentioned above, the abutment edge, i.e. the portion 10, forms an angle α to the plane of the floor portion 4 which is preferably about 135°. By means of this arrangement, it is ensured that the floor part 2, during its rotational movement, is automatically centered in the opening of the floor part 1. In other words, the floor part 2 is supported by the rollers 13 in a self- centering way. It is appreciated that a sufficient self- centering is also obtained with other angular values, for example when α is within the interval 90-160°.

As has been mentioned above, the wheel axles form an angle β to the plane of the floor portion 4 which is preferably about 160°. It is appreciated that β can alternatively assume other values, for example within the interval 135-180°.

In the foregoing, the invention has been described starting from a specific embodiment. It is appreciated, however, that other embodiments can be accommodated within the scope of the invention. For instance, the rotary function of the second floor part can be realized also if only one of the supporting elements comprises a motor.

The invention can also be realized entirely without a motor for driving the second floor part 2, in which case the driver brings the second floor part 2 to rotate relative to the first floor part 1 completely manually by means of manual rotating means, for example by taking support against the cab walls. In this embodiment, however, a locking device for locking the floor parts 1 and 2 to each other, when the desired position of the floor part 2 has been reached, is required.