The objective of the invention is a hand-operated board cutter which has a body and a cutting blade.

Gypsum board can be easily worked by cutting with a knife a cut into the cardboard layer on the first surface of the board and breaking the board in two at the cut. After this the cardboard layer on the second surface of the board can be cut through with a knife. In order to achieve a straight cutting line a liner, for example a straight-lined plank wood or a strip of board, set on top of the board to be cut is generally used along the edge of which liner the knife is moved. Supporting the liner into place for the duration of the cutting operation is tricky. Moreover, the position of the liner on the surface of the board to be cut has to be determined separately by measuring, which slows down the cutting.

The aim of the invention is to disclose a hand-operated board cutter by which disadvantages related to prior art can be reduced. The aims according to the invention are achieved by a hand-operated board cutter characterized by what is presented in the independent claim. Some preferred embodiments of the invention have been presented in the dependent claims.

The objective of the invention is a hand-operated board cutter with a body and a cutting blade, suitable especially for cutting gypsum boards. Preferably the body is a one-piece component made of plastic. The cutting blade has been attached to the body. Further, there is a slot in the board cutter for the end of a tape measure and a pull thrust for moving the board cutter. When cutting the board the end of the tape measure is fitted into the slot and the board cutter is moved by hand on top of the board to be cut by gripping the pull thrust with fingers. The tape of the tape measure is locked into set length and the tape measure is moved along the edge of the board to be cut at the same time and speed with moving the board cutter. The board cutter is gripped and moved with one hand and the tape measure is moved with the other hand. Thus the tape measure serves as a guide for the board cutter with the help of which guide the board cutter remains at a constant distance from the edge of the board during cutting. During the movement of the board cutter the cutting blade makes a cut onto the surface of the board, i.e. it cuts through the tension resistant surface layer of the board and makes a groove into the layer below the surface layer. The cut can be made at the same place on both sides of the board after which the board can be broken by hand at the cut. In a preferred embodiment of the board cutter according to the invention there is a plate-like base in the body with a substantially even first surface and the cutting blade is on said first surface. Preferably the cutting blade is substantially perpendicular to the first surface. The board cutter is moved on the surface of the board to be cut so that the first surface of the base lays against the surface of the board to be cut. The cutting blade protruding from the first surface then penetrates the surface layer of the board to be cut. Thanks to the even first surface of the base the board cutter and the cutting blade are always in the right position with respect to the board to be cut when moving on the board. In another preferred embodiment of the board cutter according to the invention there is a second surface in the base and the pull thrust has been arranged onto the second surface. By gripping the pull thrust it is thus easy to press the base against the board to be cut.

In yet another preferred embodiment of the board cutter according to the invention said slot comprises a first groove and a second groove forming a substantially right angle with the first groove. As is well known, tape measures have a metal tape which recoils, at the free end of which there is a metal bite tang turning in the right angle from the plane of the measure. The end of the tape measure can be fitted into the slot so that the free end of the measure settles into the first groove of the slot and the bite tang settles into the second groove of the slot. The end of the tape measure then locks immovably into the slot. The second groove and the cutting blade can be substantially aligned on different sides of the base, whereupon the cutting blade settles automatically at the end of the tape measure, i.e. at the zero point of the measuring scale. In yet another preferred embodiment of the board cutter according to the invention said first groove is in the pull thrust. Preferably the first groove extends through the pull thrust, i.e. the ends of the first groove open to the opposite sides of the pull thrust. The end of the tape measure can thus be fitted into the slot from either the first or the second side of the pull thrust. This feature makes possible the use of the board cutter alternatively either with the right or the left hand according to the cutting situation. Preferably there is a dent in the pull thrust for gripping with a finger and the mouth of the first groove opens to said dent. In that case the finger pressing against the dent keeps the end of the tape measure from coming out of the first groove during cutting. An advantage of the board cutter according to the invention is that it makes it possible to cut boards entirely without liners. This speeds up and facilitates board cutting considerably.

Fig. 1 shows a board cutter according to the invention seen obliquely from above,

Fig. 2 shows a board cutter according to the invention to which the end of a tape measure has been attached,

Fig. 3 shows a board cutter according to the invention seen from the side,

Fig. 4 shows a board cutter according to the invention seen from the front, Fig. 5 shows a board cutter according to the invention seen from the side, and

Fig. 6 shows a board cutter according to the invention seen obliquely from below.

In Figs. 1-6 has been described a hand-operated board cutter according to the invention depicted from different directions. The board cutter includes a one-piece body 2 of plastic material in which there is a plate-like base 5. The base has a substantially even first surface 5a and a second surface 5b. A cutting blade 2c has been attached to the body so that the tip of the blade protrudes from the first surface of the base. The cutting blade is substantially perpendicular to the first surface. The height of the blade as measured from the plane of the first surface is a few millimetres.

On the second surface of the base 5 there is a projection-like pull thrust 2b at the second edge of which there is a groove-like dent 7 (Fig. 3). In the pull thrust there is a first groove 6a in the direction of the first surface extending through the pull thrust, i.e. from the first side of the pull thrust to its second side. The open mouth of the first groove opens to the dent. In the pull thrust there is an additional second groove 6b which connects from its first edge to the first groove (Fig. 4). The second edge of the second groove extends to the base 5. The open mouth of the second groove opens partially to the dent. The second groove and the cutting blade 2c are substantially aligned on the opposite sides of the base 5.

The first and the second groove together form a slot 2a into which the end of a tape measure can be fitted. Tape measures have a recoiling metal tape at the free end of which there is a metal bite tang turning in the right angle from the plane of the measure. The end of the tape measure can be fitted into the slot so that the free end of the tape settles into the first groove of the slot and the bite tang settles into the second groove of the slot. The end of the tape measure then locks immovably into the slot. The end of the tape measure can be fitted into the slot either from the first side or from the second side of the pull thrust. This feature makes possible the use of the board cutter alternatively with either the right or the left hand. The pull thrust can be gripped by squeezing it with the thump and the middle finger and pressing the forefinger into the dent of the pull thrust. The finger pressing against the dent closes the open mouths of the first and the second slot opening to the dent and prevents the end of the tape measure from coming out of the slots during cutting.

When cutting board, the tape of the tape measure is locked into set length and the tape measure is moved along the edge of the board to be cut in the same direction with the board cutter moved on the surface of the board to be cut. The tape measure thus functions as the guide of the board cutter by means of which the board cutter remains at a constant distance from the edge of the board during cutting. No separate liner is thus needed for cutting but the edge of the board to be cut serves as a liner in the cutting operation which liner the cutting blade follows via the tape measure that is locked into set length. During the movement of the board cutter the cutting blade makes a cut onto the surface of the board, i.e. it cuts through the tension resistant surface layer of the board. After cutting the board can be broken in two by hand at the cut. After breaking, the possible surface layer on the second surface of the board can be cut through with the same board cutter.

Some preferred embodiments of the board cutter according to the invention have been described above. The invention is not limited to the solutions explained above but the inventive idea can be applied in different ways within the scope of the claims.