This invention relates to a method of loosening the logs in a bundle of timber or paper wood from each other which bundle is kept together by at least one band, and a device for carrying out the method.

When timber logs and paper wood are delivered to sawmills and pulpmills, the logs and the wood are often bundled by means of relatively thick steel bands.

Therewith each bundle is formed by means of two steel bands, positioned at a distance from each other.

Up to now the steel band has been taken awaγ manually. Therewith the bundle of timber logs has been laid down into a cradle, there having been a certain distance between the bundle and the ground surface. Thereafter a person by meanβ of a special pliers has cut off the steel bands and then pulled away these ones. This has been made possible thanks to the fact that the bundle has been placed in the cradle so that the timber logs have not squeezed the steel band against the ground.

There are several drawbacks connected with the known method of taking away the steel bands. Firstly, there is required a manual working effort resulting in an expensive handling. Secondly, there is required a cradle for making the handling possible at all. Third¬ ly, there is a risk for accidents in this working moment. Thus, the risk is large for squeezing accidents and accidents cauβed by the band during the cutting.

Therefore, there have been desires of making this work¬ ing moment without the special manual working effort.

By Derwent'ε Abstract of SU 1134-255 is previously known a device for cutting off bands surrounding a roll. This cutting device comprises a wedge means, which is intended to be brought in under the band, and

two piston means which are intended to squeeze the band against the wedge means. The cutting device further comprises two knife means which are intended to cut off the band. Thus, this known cutting device is a very compli¬ cated and unnecessarily expensive construction, which should be very sensitive for soiling and icing.

This invention has in contrast to the known device a construction that is robust and unsensitive for blows and jerks. Moreover, the construction is unsensitive for soiling and icing.

Another important difference between the devices is that the band is detained after the cutting moment in the present invention while it should be impossible in the known device to detain the band, since the cutting takes place at the same time on both sides of the wedge means 4.

The present invention intends to remove the problem with known technique. This has been made possible by a new method for cutting and taking away the bands and a new device for carrying out the method. The invention has the characterizing features which are apparent from the accompanying claims .

The invention shall be described more closely with reference to the accompanying drawings, in which Fiα . 1 shows a front view of the device, partly in section, Fio. 2 shows a section along the line 11—11 in Fig. 1, Fio. 3 shows the means according to Fig. 2 in an en¬ gagement with a band that shall be cut off and Fio . 4 shows the device fastened to a crane beam of a grip loader.

Referring to Fig. 1 is shown there the device in a resting position and in the position it has when the cutting moment has been finished. The device comprises an elongated cylindrical casing 1, which is preferably circular-cylindrical. The casing is preferably made

of a thick steel plate so that it can resist a strong outer impact. The casing 1 comprises two chambers 2, 3, each containing a piston means 4, 5. These piston means can be pushed into and out of the casing, for instance with the aid of hydraulic means. In Fig. 1 the piston means 4, 5 are shown completely pulled in into the casing 1. Each piston means 4, 5 has a longitudinal, central bar 6 which in each end has a cylndrical means 7, 8, which is preferably circular-cylindrical if the casing also has that form, and the cross-section of which has a radius which is somewhat less than the radius of the casing. For sealing against the inner wall of the casing the means 7, 8 at its periphery have one or several gaskets 9, 10 made of a suitable mate- rial. By applying pressure, for instance by means of hydraulic oil, on the inside and outside, respectively, of the means 7, 8 it is accordingly possible to get the piston to move inwards or outwards in relation to the casing 1. In order to achieve this movement of the piston 4, 5, it is of course necessary to have only one cylindrical means 7, the means 8 suitably constituting a cylindrical bushing functioning as a guide for the piston 4, 5 in the casing.

The central bar 6 has at its end being outside the casing an arm 11 with an extension in radial direction in relation to the casing 1. The one end of the arm 11 has a portion 12, which is obliquely directed down¬ wards/inwards in relation to the casing 1. This portion 12 comprises a cutting means 13 and is intended to co- operate with a support 14 fastened to the casing. The portion 12 and the support 14 are shown more closely in Figs. 2 and 3.

The other end of the arm 11 is provided with a portion 15, which extends inwards in relation to the casing in its axial direction. This portion 15 suitably comprises a bar functioning as a guide for the piston

means during its inwards-directed and outwards-directed movements in relation to the casing. The arm 11 is pre¬ ferably fastened onto a reduced portion of the bar 6 by means of nuts 15. The device is intended to be fastened onto the beam of a lifting crane or the like. This can be made by means of bars 17, 18 which are movably fastened to a holder 19, 20 on the casing.

Referring to Figs. 2 and 3 is shown there in more detail the design of the means which are intended to cut off a steel band or similar which surrounds for in¬ stance a bundle of timber logs or paper wood. The por¬ tion 12 comprises three parts positioned beside each other: a first outer part constituting a cutting knife 13 which is exchangable, a middle part 21 for position¬ ing the steel band and a second outer part 22 with a rounded top portion. The middle part 21 preferably has a wedge-formed upper portion intended to rest against a corresponding recess in the support 14, when the piston means 4 and 5 is completely pulled in into the casing. The portion 12 has such a width that, when this one rests against the support 14, the parts 13 and 22 are positioned radially outside the support 14.

Normally the cutting of the steel band is made by the fact that there is formed an indication of a frac¬ ture at the point P^ when the pointed cutting knife 13 touches the band. When then the unit comprising the cutting device is lifted upwards, the band breaks.

The band can also be cut off by a direct cutting function due to cooperation between the means 12 and

14. Therewith the inner corner edge 23 of the knife 13 should be able to overlap the outer corner edge 24 of the support 14, which edge 24 is preferably pointed and positioned closest to the edge 23. Due to the fact that the parts 13, 21, 14 are pro¬ vided with pointed corner edges, the positioning of the

steel band 25 is facilitated when the cutting moment starts (see Fig. 3) .

The other corner of the support 14 is preferably rounded and is intended to rest against a corresponding rounded recess in the portion 12 at the point P . More¬ over, as has been mentioned, the upper portion of the part 22 is rounded. These facts taken together makes that the steel band 25 when the means 12, 14 are moved towards each other will be squeezed between the means 12, 14, especially at the rounded portions of the parts 14, 21 and 22.

As has been mentioned previously this described device is preferably intended to be used when cutting off steel bands surrounding a bundle with timber logs or paper wood. Therewith the device is suitably mounted onto different types of lifting cranes: stationary, band-borne or wheel-borne cranes. The device is due to its durable and strong construction very suitable to be applied onto a grip loader, that is a unit which is provided with at least two gripping claws which can grip a bundle of timber logs. The device patent applied for is therewith suitably so fastened to the grip loader that its gripping claws surround the same. In Fig. 4 the device is indicated with an arrow. Thanks to this position, the device will rest against logs of the timber bundle which, as has been mentioned previously, is usually surrounded by two steel bands at a distance from each other.

If there is a desire that the device shall come into function, the two piston means 4, 5 are pushed out of the casing 1 so far that the lower ends of the means 12 come axially outside and radially inside the steel bands surrounding the timber bundle. Thereafter the piston means 4, 5 are pushed into the casing at the same time as the means 12 are brought in under respec¬ tive steel band 25. These ones are now pulled in the

direction towards the casing 1 of the device, an indi¬ cation of fracture arising in the band at the point P , that is where the knife 13 touches the band when pull¬ ing in the means 12. During the continuous pulling in of the means 12 this one touches against the means 14. Herewith the band is squeezed between the means 12 and 14 preferably between the rounded portions at the point

After this moment of pulling in, the unit compris- ing the device patent applied for is lifted upwards, whereby the band breaks at the point Pj_. During the continuous lifting of the unit upwards the steel bands cut off are coming along and can be taken away.

The great advantage with the invention is that the troublesome and risky working moment comprising cutting off steel bands and taking away the same has been able to be mechanized, whereby the problems have been elimi¬ nated. Moreover, the need of a special cradle for the timber bundle is eliminated. Instead the timber bundle can be put directly on the ground when the -cutting moment shall take place.

In the drawings and in the description a prefer¬ able embodiment of the invention has been illustrated. Of course, it is possible within the scope of what has been mentioned in the following claims to modify the invention. Thus, for instance the casing can have square or rectangular cross-section instead of round with corresponding changes of the means 7 and 8. Be¬ sides that it is possible for the pistons 4 and 5 to be able to move independently of each other, which means that only one cutting means is utilized.

In the patent application has been mentioned that the invention preferably shall be used when loosening logs in a bundle of timber or paper wood. Of course it is possible to use the invention patent applied for in other situations where cutting of steel bands shall be made.