Screwing device

1. Screwing device ( 30 ) for screwing boards ( 2 ) on underlying crossbeams ( 3 ) in such a way, that the screws are screwed tilted in from the edges ( 5 ) of the boards ( 2 ), comprising:

a base ( 7 ) with an oblong foot ( 8 ) standing in use on the upper side of the boards ( 2 ),

two arms ( 9 ) extending tilted out from each their end of the foot ( 8 ), and

two opposite screw drivers ( 10 ) which are mounted on each their arm ( 9 ) and each is arranged with means for conveying a disposable belt ( 34 ) of releasable screws ( 6 ) and for stepwise screwing in screws ( 6 ) from the belt ( 34 );

wherein the foot ( 8 ) comprises a left and right foot part ( 11 , 12 ) separated by a space ( 13 ), and of an element extending across the space and connecting the two foot parts ( 11 , 12 );

wherein the element is a bolt ( 14 ) having a left part ( 15 ) which is disposed axially adjustable in the left foot part ( 11 ), and a right part ( 16 ), which is slideable disposed in the right foot part ( 12 ) influenced by a compression spring ( 17 ).

2. Screwing device ( 30 ) according to claim 1 , wherein a chamber ( 18 ) is formed in the right foot part ( 12 ), that the right part ( 16 ) of the bolt ( 14 ) is extending into this chamber ( 18 ) with a head ( 19 ) bearing against the right end wall ( 20 ) of the chamber ( 18 ), and that the compression spring ( 17 ) is placed between the head ( 19 ) of the bolt ( 14 ) and the left end wall ( 21 ) of the chamber ( 18 ).

3. Screwing device ( 30 ) according to claim 1 , wherein the left foot part ( 11 ) is formed with a longitudinal bore ( 22 ), that the left part ( 15 ) of the bolt ( 14 ) is extending into this bore ( 22 ), and that the left foot part ( 11 ) is adapted to tightening the left part ( 15 ) of the bolt ( 14 ) in a selected position in the bore ( 22 ).

4. Screwing device ( 30 ) according to claim 3 , wherein the underside of each of the two foot parts ( 11 , 12 ) of the foot ( 8 ) is formed with a transverse rib ( 23 ) that has a height equal to or less than the thickness of a board ( 2 ) and a width equal to or narrower than the width of the space ( 4 ) between two boards ( 2 ), and that the distance between the inner sides of the ribs ( 23 ) on the two foot parts corresponds to the width of a board ( 2 ) when the foot parts ( 11 , 12 ) are pulled sufficiently far apart from each other during overcoming the compressive force of the compression spring ( 17 ) of the right foot part ( 12 ), and the left part ( 15 ) of the bolt ( 14 ) is tightened in the previously selected position in the bore ( 22 ) of the left foot part ( 11 ).

5. Screwing device ( 30 ) according to claim 4 , wherein at least an upper portion of each of the arms ( 8 ) of the base ( 7 ) is divided into two pieces by a slot ( 26 ) having the same or a greater width than the diameter of a screw ( 6 ), and that a bore ( 27 ) having the same or a larger diameter than the head of the screw ( 6 ) is extending through the slot ( 26 ) and at least partly through the rib ( 23 ).

6. Screwing device ( 30 ) according to claim 5 , wherein a support ( 28 ) is placed at the bottom of each bore ( 27 ) to keep a screw ( 6 ) in position during the operation of screwing in the screw.

7. Screwing device ( 30 ) according to claim 1 , wherein a protruding rod ( 24 ) is secured at a distance above the underside of the foot ( 8 ) on one side of the left foot part ( 11 ).

8. Screwing device ( 30 ) according to claim 1 , wherein the screws ( 6 ) have a right-hand thread ( 35 ) at a lower part and a left-hand thread ( 36 ) at a top part.