The invention can also be considered to concern a device in working apparat- uses showing working equipments for carrying through a working operation on a workpiece, article, object, goods, product or the like. At this, the device comprises at least a measuring device which can be read off on the workpiece.

There is a need of a device for, for example, trucks, where the operator's position is situated at a distance from the working equipment of the truck and the object which will be handled, which device can measure the position of the truck or its working device in relation to the object in question.

Another need is that such a measuring device will be able to be read off by the operator without having an injurious effect on the safety of the work. Yet another need is that a use of the measuring device does not involve that the work is going to be more complicated but can be carried out without waste of time. Otherwise, there is a risk of the fact that the device is going to be utilized.

Within, for example, the wood working industry different packages or packets of wood are handled by forklifts, as in loading, unloading, storing and stacking. At this, it is usual that packages of wood are stacked on top of one another with sticks between and what is even more important in this example is that stacking often happens next to another stack of wood or one after the other or side by side located stacks. When, for example, a package of wood is stacked or collected, it can be difficult for the operator to decide how far the forks reach underneath a package. This is not in least inconvenient if the forks are inserted too far, i. e. the truck has been brought forward towards the stack to a distance from the stack which is some short. The forks of the truck are in this case projecting outside the other side of the stack and cause damage to a stack or a package of wood lying behind. Further, there is a risk of upsetting or at least distortion of the stack or package of wood lying behind. In case, the forkq of thP truck ore not inserted far enough underneath the package of wood there is a risk of dropping the package of wood or at least that the working operation must be adjusted or be done again. In this connection, it can be mentioned that a number of packages of wood and wood ready for delivery generally have to be discarded because of the lack of some kind of measuring device which can settle how far the forks of the truck reach underneath the package of wood or happen to project on the back of the package of wood. In other words, it is of importance that the forks of the truck have an intended or satisfactory position or in-stick underneath the package.

However, a device in accordance with the invention fulfils the set requirements while, at the same time the said inconveniences can be eliminated. Besides to maintain the safety in work, it is even in such a way that use of a device in accordance with the invention simplify the work and avoid waste of time and other irritations which can arise in connection with the fact that the work does not float as intended.

The device in accordance with the invention is characterized in that a measur- ing device comprises at least a light source, for example, in form of a laser light source, as a so-called line laser, which is arranged on the truck in such a way that the light beam of the light source will impinge the object to be handled.

According to an embodiment of the device in accordance of the invention the measuring device comprises two light sources, preferably in form of so-called line lasers, which are arranged at a distance from each other and directed at an angle towards each other in such a way that their respective light beam intersect or cross each other at a predestinated distance from the light sourses.

In another embodiment of the device in accordance with the invention the measuring device is read off on the object.

According to yet another embodiment of the device in accordance with the invention the light source is arranged on the lift bracket.

The invention relates also to a method to effect reading and/or measuring of the position for a movable object in relation to a stationary object, for example, the position for a working equipment in relation to an object which is to be handled or worked, as a lift bracket or equipments of a forklift in relation to a package of wood, whereby at least a measuring device is arranged for a visual reading of the position for the movable object in relation to the object. The method is characterized in that the movable object is provided with a light source which emits at least one light beam, whereby, when the light beam reaches a predestinated position on the object, the light beam is read off and intended working operation is carried through.

In an embodiment of the method in accordance with the invention the movable object is a truck with a lift bracket and the stationary object is a package of wood. The method is characterized in that the truck or the lift bracket is provided with at least two light sources, each arranged to emit a light beam in such a way, that the light beams cross each other at a predestinated distance, for example, at such a distance that when the light beams cross each other on the package of wood and the forks in the meantime have been brought in below the package of wood, the forks extend underneath the package of wood essentially as far as the depth of the package of wood or in any case not further than the depth of the package of wood, after which handling of the package of wood is carried through.

Briefly, a device in accordance with the invention could be expressed as a device in working apparatuses showing working equipments for carrying through a working operation on a workpiece, article, object, goods, product or the like, whereby the device comprises at least a measuring device which is read off on the workpiece.

Further characteristics and advantages of the device and the method, in accordance with the invention, will in the following description be apparent by an embodiment example, whereby a simultaneous reference will be made to the accompanying schematic drawings, of which Fig. 1 shows from above a truck and stacks of packages of wood, whereby the working equipment of the truck is in front of the packages of wood, Fig. 2 shows a front view of a part of the stacks of packages of wood according to Fig. 1 or the truck operator's sight of the packages of wood, Fig. 3 shows from above the truck and the stacks of packages of wood according to Fig. 1, whereby some of the working equipment of the truck is underneath a package of wood in a front stack of the packages of wood, Fig. 4 shows a front view of a part of the stacks of packages of wood according to Fig. 3 or the truck operator's sight of the packages of wood, Fig. 5 shows from above the truck and the stacks of packages of wood according to Figs. 1 and 3, whereby the working equipment of the truck is underneath or optimum underneath a package of wood in a front stack of the packages of wood or underneath that package of wood mentioned in Fig. 3, Fig. 6 shows a front view of a part of the stacks of packages of wood according to Fig. 5 or the truck operator's sight of the packages of wood, Fig. 7 shows a front view of a part of a package of wood with projected light beams from a measuring device or light sources, Fig. 8 shows a front view of a part of a package of wood too, with projected light beams from a measuring device or light sources, Fig. 9 shows a front view of a part of a package of wood as well, with projected light beams from a measuring device or light sources and Fig. 10 shows a front view of a part of a package of wood, as previously, with projected light beams from a measuring device or light sources.

With the reference designation 1 in Figs. 1,3 and 5 is shown a working apparatus as a movable object with a working device 2 showing equipments 3.

According to the embodiment example the working apparatus 1 is a truck with a lift bracket 2 showing a pair of projecting forks 3. Further, it is shown in Figs. 1,3 and 5 an object 10 as a stationary object and in form of packets or according to the embodiment example a first stack 11 and a second stack 12 of packages of wood. Each package of wood has a front 14 and a back 15. From the figures it appears also and schematically a truck operator 20 and an end part 23 or a free end part or the end of the equipment 3 or the forks 3.

The device in accordance with the invention comprises at least a measuring device which is arranged at least to be able to be read off visually and in that respect at least on that object 10 which will be handled by the working apparatus 1. According to the embodiment example shown, the measuring device comprises two light sources 4, preferably in form of laser lights which are arranged as so-called line lasers, i. e. each of the light sources 4 emits at least a light beam 5 in form of a line. The light sources 4 are arranged at a distance from each other and directed at an angle towards each other, whereby the light beams 5 from the two light sources 4 will intersect or cross each other in one place 6. By means of setting of the light sources 4 and their relative angle it can be effected that the place 6 for intersection or cross- ing of the light beams 5 occur at a predestinated distance from the light sources 4. According to the embodiment example, the light sources 4 are arranged on the truck 1 or its lift bracket 2 and directed in such a way that the place 6 for intersetion or crossing of the light beams 5 is at least situated above the equipment 3 and in the case of in pairs arranged forks 3 between the forks 3 or in between or essentially in between the forks 3 or at least situated in a position which, when the light beams 5 illuminate the object, is easy to observe by the operator 20, see for example Fig. 1.

Further, the light sources 4 are arranged and directed in such a way that the said place 6 for intersection or crossing is situated in a position between the operator 20 and the free end parts 23 or ends of the forks 3. Besides, according to the said embodiment example, the light sources 4 are arranged to emit light beams 5 which are parallel with each other on a projecting surface 9, whereby a distance between respective light beam 5 can be observed or read off in different positions for the truck 1 in relation to the object 10. For the sake of simplicity the light sources 4 can be arranged and directed in such a way that their respective light beam 5 emits horizontally or perhaps even more appropriate vertically. Irrespective of which, the said parallelly light beams 5 are going to intersect in a line 6.

In the representation according to Fig. 1 the truck 1 is situated in front of or is on way towards an object 10 for collecting a package of wood 11 from a stack of packages of wood, i. e. the package of wood 11 is placed on top of another package of wood 13 with sticks 19 between the packages of wood 11,13, whereby a space 16 exists between the packages of wood or under the first package of wood 11, see also Fig. 2. For the collecting of the package of wood 11 the operator 20 is going to bring in the forks 3 underneath the package of wood and into the space 16 and lift the package of wood from the stack. The operator 20 has no possibility to see the stack 12 lying behind the package of wood.

In course of the conveyance of the truck 1 towards the object 10 and in the position shown for the truck 1 the operator 20 can observe on the object 10 two lines 7 and 8 of light beams 5 from the light sources 4, i. e. the light beams 5 are projected on the surface 9 on the object 10 or the packages of wood 11,13. In the cource of the conveyance of the truck 1 towards the object the two lines 7,8 from the light beams 5 approach each other which is illustrated by the arrows 17 and 18 in Fig. 2. This will probably also be evident from Figs. 3 and 4 and in a comparison of the shown, where the truck 1 has been brought forward nearer to the object 10 in the direction of the arrow 24, i. e. the forks 3 are partly situated under the package of wood 11 but their ends 23 are still situated at a distance from the back 15 of the package of wood 11 and at a distance from the package of wood 12 lying behind in the other stack or its front 14. At this, the two lines 7 and 8 from the light sources 4 have approached each other on the projecting surface 9.

It exists in timber yards packages of wood with, for example, a depth of 1 metre and 1,60 metre. Sometimes must maybe objects be moved showing larger depth or are wider. For that reason the length of the forks 3, shown by the trucks 1, is at least of equal length or preferably somewhat longer than the largest depth shown by the objects 10 or said object. That is the cause why it is difficult for the operator 20 to decide how close he has to move the truck 1 towards the object 10 to ensure a lift. Thus, it happens that the operator 20 moves the truck 1 too close the object 10, i. e. there is a risk that the ends 23 of the forks 3 hit objects 10,12, goods and the like stacked behind that object 10,11 which is nearest the operator 20 and by that damage the object, the goods, etc. or cause even worse injury, as collapse of the stacks, accidents, etc.

The packages of wood 11,12, 13 shown in the embodiment example have a depth of one metre, why the operator 20 should preferably insert the forks 3 underneath the object 10 one metre, however not more than one metre to prevent that the forks 3 hit against an object, goods or other things lying behind, as a wall or another object. For that reason is the measuring device or the light sources 4 according to the embodiment example arranged and directed in such a way that their light beams 5 or 7 respectively 8 intersect in the place 6 for intersection or in the line 6, i. e. one metre from the ends 23 of the forks 3, see also the reference designation 22 illustrating a length of one metre from the ends 23 of the forks 3.

When the truck 1 moves even nearer to the object 10 the operator 20 can observe on the projecting surface 9 or on the object 10 how the lines 7 and 8 approach each other more and more. When the lines 7 and 8 are united into one line, i. e. the place 6 for intersection of the light beams 5 is projected on the surface 9 of the object 10 as one line, the operator 20 gets the inform- ation that the forks 3 have right in-stick underneath the object 10 or the package of wood 11, i. e. the operator 20 stops the conveyance of the truck 1 and carrying through the working operation, see Figs. 5 and 6. At this, the ends 23 of the forks 3 reach to the back 15 of the adjacent package of wood 11 but does not reach to the package of wood 12 lying behind or its front 14.

The measuring device or said light sources 4 can, for example, be arranged adjustable between two or more positions for measuring and indicating differ- ent depths of in-stick for the forks 3 or according to an embodiment be doubled, mentioned because of the embodiment example shown, whereby two light sources 4 are arranged and directed for intersecting or uniting light beams 5,7, 8 at a place 6 of crossing or in a line 6 of crossing one metre from the ends 23 of the forks 3 and two light sources 4 for intersecting or unit- ing light beams 5,6, 7 one metre and 60 centimetres from the ends 23 of the forks 3. When measuring devices are arranged for two or more measures a change-over switch can be arranged so the operator 20 in an easy way is able to switch between different measurings, distances or desired markings.

In this connection it can be mentioned that a railway company, which transport goods, has packets of goods with a depth of 1,20 metre and 1,80 metre. In harbours are used trucks with forks showing a length up to 2,50 metres.

The measuring device can also comprise an ultrasound source which is arranged to emit a signal when the light beam 5 of the light source 4 reaches intended position on the object 10.

Further, the measuring device can comprise other reading means as a camera, showing the object 10 and intended marks 5,7, 8, whose image can be read off on a screen 21 or similar which is arranged in readable nearness of the operator 20, see Fig. 1.

A measuring device or a device in accordance with the invention can also present another information to the operator 20 as how the object 10 is packed.

Thus, wood, boards or similar in timber yards are stacked and bundled to packages 11,12, 13. The side surface 9 or the side surfaces of the packages are often smooth or should be. If that is not the condition, the operator 20 receives information about the condition through the measuring device when the light beam 5 of the light source 4 illuminates the object 10.

Thus, in Figs. 7-10 is shown schematically a projecting surface 9 on an object 10 and which, when projecting a light beam 5 from a light source or light sources according to previous described and shown embodiment example, inform of, according to the representation in Fig. 7, that the object 10 or the package is smooth or has a smooth surface.

It is evident from Fig. 8 that the bundled boards or similar in the package are laid irregularly or displaced with one another, i. e. the side surface of the object 10 is not smooth.

In the case shown in Fig. 9 one receives the information that the package lean backwards, i. e. its upper part is displaced or situated farther away from the operator, the truck or its working device than the lower part of the package. Because of the displacement of the centre of gravity it can, in this case, exist risk of the fact that the package is unstable. In collecting, the package can begin to cradle or even fall by the movement of the working device or in stacking, the package can come to hit against an object lying behind.

According to the case shown in Fig. 10 it is on the contrary, i. e. the package is lean forward. The upper part of the package is thus displaced like a stoop- ing in relation to its lower part or bottom and involving corresponding or similar risks as in the previous described case.

The measuring device, the device and the method in accordance with the invent- ion can certainly be used for other working operations, as in stacking, where- by it facilitates for the operator 20 to look after that the object which is during stacking will be in line with the previously placed or stacked objects.

Without exceeding the scope of the concept of the invention modifications of the device and method in accordance with the invention should be possible.

Thus, the measuring device and the method can be used in handling or treatment of other objects, as in rolls provided with bobbins, where the truck or its lift bracket is perhaps equipped with only a projecting spear, horn or similar for in-stick into the bobbin. At this and in other connections, it will proba- bly be possible to use only one light source as a measuring device and in yet other connections to arrange the light source or the light sources for project- ing of lines, spots, circles or other markings and in lines extending horizont- ally or at an angle. Of course, it is also possible to combine the measuring device in accordance with the invention with other kinds of measuring means.

The method and device are thus not restricted to what has been evident from the embodiment example shown and described but soley by the following claims.