Background Art In working vehicles of different types there are often a plurality of operating devices for controlling different functions of the vehicle. The design of these devices is most important for how comfortably and effi- ciently the work with the vehicle can be carried out. In the following particularly trucks will be discussed, but it will be appreciated that corresponding problems arise also in other types of working vehicle, and that corre- sponding operating means can be used also for such ve- hicles.

For trucks, use is traditionally made of a plurality of different levers for operating the fork. These levers are in most cases movable in one direction only and have a similar design. A drawback of this traditional solution is the great risk of mixing up the levers, which may have fatal consequences since the loads that are handled can be very large. Further it may be difficult to make small and well-controlled motions when operating with merely the handle of the lever as support and, thus, not having anything to which the motion can be related. There is also a risk that the user, if his hand rests on these operating means while performing other operations, by mistake performs operations that were not intended.

These prior art operating devices are used espe- cially for mechanical control systems, in which a rela- tively large motion and force are required.

In modern working vehicles, however, the control system is often electronic, thus allowing greater liberty as to the design and placing of the operating devices.

In these devices, a plurality of operating means can also be combined. In this manner, the risk of mixing up the operating means decreases. Examples of such prior art operating devices are Applicant's own control"Tergo" and Jungheinrich's control"Multipilot".

Also this type of control suffers, however, from the drawback that it is difficult to make small and control- led motions since it is difficult to relate the motion to something. Furthermore there is also the problem that it is easily to touch the controls by mistake, for example when driving across an uneven base, and thus perform op- erations that were not intended and that may cause great damage. In fact, this problem is greater in these devices than in the mechanical ones since a much smaller motion and force are required.

Objet of the Invention Therefore an object of the present invention is to provide an operating device for working vehicles which wholly, or at least partly, obviates these drawbacks of the prior art constructions.

This object is achieved by an operating device according to the appended claims.

Summary of the Invention The invention relates to a manual operating device for working vehicles comprising an operating part which is movable in one direction and which is intended, when in use, to be held by the user's hand. The inventive device is characterised in that it further comprises a stationary support and reference part arranged adjacent to the movable part and, at a side of the same, facing perpendicular to the direction of motion of the movable part. As a result, a support and a reference are provided for the user, when his hand is placed on the operating

device, thus increasing safety. Moreover, the operation will be both easier and more comfortable.

Additional advantageous embodiments of the invention are stated in the subclaims.

Brief Description of the Drawings In the accompanying drawings Fig. 1 is a top plan view of an operating device according to a preferred embodiment of the invention; Fig. 2 is a perspective view, obliquely from above and from the side, of the operating device in Fig. 1; and Fig. 3 is a side view of the operating device in Fig. 1.

Description of Preferred Embodiments The invention will now be described in more detail with reference to the accompanying drawings.

The operating device according to the invention comprises a movable part 1 and a stationary part 2. The movable part is movable in one direction, which prefer- ably essentially coincides with the direction of the user's forearm in operation. In this manner, the movable part can be moved forwards and backwards, and preferably springs or the like are provided to strive to return the movable part to a normal position, which, for example, is in the centre of the space of motion. The direction of motion is illustrated by arrow R in Fig. 3. The movable part can advantageously be designed as a lever, in which case the motion will be arcuate.

The stationary part is arranged adjacent to the movable part, and beside the same in such manner that the motion of the movable part is not impeded. Consequently, the stationary part extends in a direction perpendicular to the direction of motion of the movable part. In this way, the user's hand, when in operation placed on the movable part, will at least to a certain extent be in contact with the stationary part. As a result, a con- tinuous reference to the motion of the movable part is obtained. Moreover, the user can easily move his hand

between the movable part and the stationary part and, in this way, easily move his hand to the stationary part when the truck is to be driven or the like. This drasti- cally reduces the risk of unintentionally performing motions by means of the operating device.

The movable part 1 has an upper part which is de- signed for the user's hand, when operating, to be able to rest on the same. The upper part is preferably ergo- nomically designed and rounded for comfortable use. Since there are no projecting parts of the operating device, also the risk of getting stuck with one's clothes or the like is reduced. The upper part preferably has an extent which is essentially the same as an intended user's palm.

The upper part thus is the size of a clenched fist and is comfortable to hold and grasp.

Preferably the movable part may also comprise addi- tional operating means arranged so as to be reached by the user's fingers when his hand is placed on the movable part. As a result, a multifunctional device is provided, in which a plurality of operating functions can be per- formed with a single manipulation. Thus, an operating means 3, preferably of a tiltable type, can be arranged on a side of the movable part which is directed towards the direction of motion and which, when used, is directed away from the user. Thus this operating means can be operated, for example, by one or all of the user's index finger, middle finger and ring finger. Furthermore an operating means 4, also preferably of a tiltable type, can be arranged on a side of the movable part which is not directed towards the direction of motion and which is directed away from the stationary part. This operating means can thus be operated by the user's thumb.

Preferably, the movable and the stationary part are similarly designed and are essentially the same size. In this way, the operating means constitutes an aestheti- cally and ergonomically attractive unit.

Both the stationary and the movable part can be made of, for example, plasticised polyurethane which is foamed over a steel core.

The operating device is suited mainly for electric actuation by an electronic control system. In particular the device is suited for operating the fork of a truck.

The displacement of the movable part can suitably be used to control the raising and lowering of the fork. Further the front operating means can be used for frame displace- ment inwards and outwards, or fork rotation clockwise and anticlockwise. The thumb control arranged on the side can be used for e. g. tilting downwards or upwards, or lateral displacement to the left or to the right. In this way, a logical coupling between the operating motions and the actual fork motions is obtained, which results in quick understanding and learning for the users. However, which functions are suitable to control with the aid of the respective means are, however, dependent on what type of working vehicle is intended. Fundamentally it is suitable to control the basic function by the displacement of the movable part, and two of the most important or most frequent other basic functions with the aid of the addi- tional means.

By means of the inventive operating device, a simple and efficient operating tool is provided, which offers support to the user's hand when required and besides a reference point in operation. The invention has been described with regard to the operation of the fork of a truck. However, it will appreciated that it can also be used in many other types of working vehicles, such as wheel-mounted loaders, hoisting cranes, tractors etc.

Furthermore, the design of the stationary and the movable part can be modified, and other types of additional means can be used instead of tiltable switches, such as dis- placeable switches, pressable buttons and the like. Such and other obvious variants of the invention must be considered to be within the scope of the invention as limited by the accompanying claims.