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1. WO2020114618 - CANVAS STRETCHER FRAME

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

Claims

1. A canvas stretcher frame that comprises stretcher bars (1 , 2, 3, 4) that are joined together by corner clamps (6) and form a rectangular stretcher frame (5), wherein the stretcher bars (1 , 2, 3, 4) are made of profiled material, which has grooves (9), flanges (10) on the back side and also, in the middle of the area defined by the grooves (9) of the stretcher bar profile, there is a longitudinal indent (29) for giving the profiled material of the stretcher bar stiffness, wherein into the grooves (9) are mounted and fixed stretching elements (11 ) for fixing the stretcher bars of the stretcher frame with corner clamps (6) and for stretching the entire stretcher frame together with the canvas fixed to the wooden bars (21 , 22, 23, 24) installed into the grooves (31 ) formed by the flanges (35, 36) of the stretcher bar profile.

2. The canvas stretcher frame according to claim 1 , wherein perpendicular to the stretcher bar profile material, two holes (12) have been drilled and tapped into the stretcher element (11 ), which have sharp point screws (13) driven into them, and wherein parallel to the profile material of the stretcher bar, a through-hole has been drilled and tapped into the cylindrical middle part of the stretching element (11 ) along the axis of the cylinder, which has the stretching screw (14) of the stretching element (11 ) driven into it.

3. The canvas stretcher frame according to claim 2, wherein the stretching element (11 ) is placed against the end of a pair of corner clamps (6) that fix and fasten two stretcher bars (1 and 2, 2 and 3, 3 and 4, 4 and 1 ) together, and the blunt end of the stretching screw (14) is pressed against both corner clamps (6) pushing them away from the stretching element (11 ) fixed into the groove (9) of the stretcher bar profile when stretching with the stretching screw (14).

4. The canvas stretcher frame according to claim 1 , wherein at least two holes (12) have been drilled and tapped into each of the hands of the upper corner clamp of the pair of corner clamps (6), fixing screws (15) are fastened into these holes for pushing the upper and lower corner clamps away from each other and for fixing them in the grooves (9) of the stretcher bar against the base of the groove (9) of the stretcher bar profile and the flange (10) of the stretcher bar profile.

5. The canvas stretcher frame according to claim 1 , wherein the stretcher frame (5) contains a further support bar (7, 8) from profile material for increasing the stiffness of the stretcher frame assembled from stretcher bars (1 , 2, 3, 4), wherein on the back side of the support bar (7, 8) profile material, there is a groove (19) identical to the groove (9) on the back side of the stretcher bar profile, which houses two support clamps (61 ), wherein the upper support clamp has two holes drilled and tapped into it and blunt point fixing screws (17) driven into them, which are used for pushing the support clamps (61 ) away from each other, wherein the ends of the support clamps (61 ) extend beyond the end of the support bar (7, 8) and have been placed into the external groove (18) on the lower external edge of the stretcher bar (1 , 2, 3, 4).

6. The canvas stretcher frame according to claim 5, wherein the width of the external groove (18) on the lower external edge of the stretcher bar (1 , 2, 3, 4) is smaller than the combined width of the two support clamps (61 ) pushed away from each other and of the slit formed by pushing them apart with the fixing screw.

7. The canvas stretcher frame according to claim 5, wherein on both sides of the lower side of the support bar (7, 8) profile there is an external groove (18) identical to the external groove on the lower external edge of the stretcher bar.

8. The canvas stretcher frame according to claim 1 , wherein the ends of the stretcher bars (1 , 2, 3, 4) of the stretcher frame (5) have been cut at a 45-degree angle, so that when assembling the stretcher frame (5), a rectangle with corners of exactly 90 degrees would form.

9. The canvas stretcher frame according to claim 1 , wherein the profiles of the stretcher bars (1 , 2, 3, 4) and support bars (7, 8) of the stretcher frame (5) are made of aluminium.

10. The canvas stretcher frame according to claim 4, wherein the cross section of the upper corner clamp is a U-shaped profile, which is formed from the base of the corner clamp and from the sides protruding perpendicularly from its edges, which have such a height that the upper corner clamp can move freely in the groove of the stretcher bar meant for the corner clamps and which has a strengthening guidance in the middle of the base of the corner clamp parallel to the sides that fits into the guide groove of the lower corner clamp, wherein the part of the guide groove pressed out from the plane of the lower corner clamp is compatible with the longitudinal indent in the stretcher bar profile and the lower corner clamp is placed between the sides of the upper corner clamp.

1 1 . The canvas stretcher frame according to claim 4, wherein the cross section of the upper corner clamp is a U-shaped profile, which is formed from the base of the corner clamp and from the sides protruding perpendicularly from its edges, which have such a height that the upper corner clamp can move freely in the groove of the stretcher bar meant for the corner clamps, and which has a strengthening guidance in the middle of the base of the corner clamp parallel to the sides and to both sides of the guidance there are guide grooves pressed down from the base, wherein the strengthening guidance is compatible with the guide groove of the lower corner clamp.

12. The canvas stretcher frame according to claim 1 , wherein stretcher bars are joined together in addition by L-shaped reinforcement corner clamps (620, 621 ) inserted into cavities of the stretching bars, where one outside reinforcement corner clamp has threaded hole for fixing screw for tightening reinforcement corner clamps against walls of the cavity of the stretcher bars.

13. The canvas stretcher frame according to claim 1 , wherein the stretcher frame (5) comprises in addition joint clamp (231 ) for connecting continuous stretcher bars, where joint clamp (231 ) comprises an upper joint clamp (232) having threaded holes arranged in staggered arrangement and a lower joint clamp (233).