SE532292C2 - Screw with machining surface - Google Patents

Description

The alternative gives chip formation and broken edges around the head, which requires finishing such as grinding and possible filling, etc.

There is thus a long known problem in countersinking screws, as above, and thus a long known need for an improved device and an improved method in countersinking screw heads.

DISCLOSURE OF THE INVENTION The present invention aims to solve the above problems by means of a screw comprising a cylindrical unit with an at least partially threaded outer casing and a head in the form of an outer flange comprising a first end surface with a radially extending extension larger than the outer casing. The outer flange comprises an edge part which delimits the outer flange in radial direction. The head comprises a fitting part comprising one or more recesses or elevations intended to engage a tool when the screw is to be screwed / rotated in or out of a detail.

The invention is characterized in that the outer flange comprises a machining surface with an extension from the edge part to the outer casing, the machining surface being arranged at an angle d) relative to a normal to the outer casing. The outer flange includes through holes extending from the first end surface through the outer flange to the machining surface. The first end surface comprises first openings for the respective holes and wherein the machining surface comprises corresponding second openings. Each second opening is limited by a leading edge and a trailing edge comprising a cutting edge arranged to machine a surface of a part in which the casing is intended to be screwed in, the hole being arranged to transport away material which the cutting edge has machined away from the part.

An advantage of the invention is that the machining surface according to the invention provides a recess in the part without chipping occurring, which reduces the risk of misalignment of the screw and a nicer recess without preparatory work. The above-mentioned part can be any construction part, but by way of example it can be mentioned that the part is a frame for a door or a frame for a window, the invention substantially facilitating assembly of doors and windows due to the fact that the working surface provides an optimal countersink without chipping at the edges with reduced risk of misalignment as a result. The screw in this example can be a frame screw comprising a through-channel, but in other construction details the screw can be solid and can have any desired size and can also be made of any material as long as countersinking can be performed in the part according to the invention.

The first end surface has a radial extension which exceeds the radial extension of the outer casing. The difference must be so great that the holes in the outer edge fit without the flange weakening in such a way that it gives way during the countersinking process.

The machining surface can be symmetrically and / or asymmetrically conical around the center of rotation in the axial joint and / or symmetrically or asymmetrically convex and / or symmetrically or asymmetrically concave. The machining surface can also have different radii along its extension in the axial direction.

The holes are each arranged in the outer end with an angle cp1 and relative to a normal N to the first end surface, the angles being substantially perpendicular to each other. The angle cpi is measured substantially in the direction of rotation, or in a tangent to the direction of rotation and substantially in the radial direction, i.e. in a direction from a center axis of the housing towards the edge portion of the outer flange. "Center axis" means an axis of rotation extending in the axial direction, substantially perpendicular to the radial direction.

According to one embodiment, the machining surface comprises recesses arranged to an extent substantially in a direction of rotation of the housing. Each recess extends substantially in the direction of rotation from the leading edge of the second opening to a position before the trailing edge of the next second opening, i.e. the cutting edge. The recesses extend so far towards the holes that the leading edge becomes lower than the trailing edge. The difference gives rise to the possibility for the cutting edge to process the material in the part, especially when the angle CD is equal to or close to zero.

The edge part has a thickness which allows the edge part to resist folding when the screw is screwed into the part in such a way that the edge part comes into contact with the part. The edge part can thus abut against the part and process the part when the screw is screwed into the part. The fact that the edge part is part of the countersinking process is an advantage as this further reduces the risk of edge chipping. When the holes transport the material away from under the machining surface, the edge part can compress the material in the part into a smooth and circular recess.

The following is an example of a screw in the form of a steel frame screw according to the invention which has been empirically proven to work very well in practice: The frame screw comprises a sleeve comprising a continuous channel.

The sleeve comprises the partially threaded outer casing and the outer flange. The sleeve is intended to be attached to a frame (door or window) and a fastening device e.g. in the form of a screw, is intended to fit in the channel to form a connection between the frame screw / frame and a structural body in which the frame is to be attached.

The outer flange has a diameter of 28mm The outer flange comprises 8 holes each with 5mm diameter and an angle: pt 0-10 degrees and an angle cp2. The holes are not displaced in radial direction.

The machining surface has no pits.

Angle CD is about 30 degrees.

The working surface is designed as a symmetrical cone.

There is 1-2mm wall thickness between the edge part and the holes. 10 15 20 532 292 The diameter of the outer casing is approx. 14mm.

The total length of the sleeve is 28mm The length of the outer casing is about 24 mm The threads have a length of 15 mm The threads have a diameter of about 17mm It is about 5 threads per cm.

The threads start about 5 mm from the edge of the outer casing.

The edge of the outer casing is chamfered for guiding the sleeve in the hole in the part.

Length of the outer flange = total length of the sleeve minus the length of the outer casing.

By length is meant axial joint and diameter racial joint.

The screw can be formed of metal, plastic, composite material, or other suitable material that is harder than the surface to be machined in the part.

An ordinary construction screw according to the invention normally lacks such a channel as is present in the frame screw and the outer casing can have a diameter of less than 1 millimeter or greater than 1 millimeter or substantially much larger than 1 millimeter, depending on what is to be constructed. The outer edge has a diameter and a thickness that is adapted to the size of the outer casing and the material in the part.

DESCRIPTION OF THE DRAWINGS The invention will be described below in connection with a number of diagrams in which: Fig. 1 schematically shows a side view of a screw according to the present invention; 10 15 20 25 532 292 F ig. 2 schematically shows a cross section along the line A-A in figure 1 according to a first example of the invention; Fig. 2a schematically shows a cross-section along the line A-A in Fig. 1 of a casing of a screw according to a second example of the invention; Fig. 2b schematically shows a cross section along the line A-A in Figure 1 of a casing of a screw according to a third example of the invention; Fig. 2c schematically shows a side view according to an embodiment of a screw according to one of Figs. 1-2b; Fig. 2d schematically shows a side view of Fig. 2c seen from the other side of the housing; Fig. 2e schematically shows a side view according to an embodiment of a screw according to one of Figs. 1-2b; Fig. 2f schematically shows a side view according to an embodiment of a screw according to one of Figs. 1-2b; Fig. 29 schematically shows a side view according to an embodiment of a screw according to one of Figs. 1-2b, and there; Fig. 3 schematically shows a side view of a screw according to the present invention comprising a cutting tip.

DESCRIPTION OF EMBODIMENTS Fig. 1 schematically shows a side view of a screw 1 according to the present invention. The screw 1 comprises a cylindrical unit 3 comprising an outer casing 4a and an outer shaft 4b. The outer flange 4b comprises a first end surface 12a which delimits the screw 1 in axial direction. The first end surface 12a is delimited in radial direction R by an edge part 12b. The outer flange 4b comprises a machining surface 12c between the cylindrical unit 3 and the edge part 12b. The screw 1 is thus divided in its longitudinal extent, i.e. Axial joint X, through the outer casing 4a and the outer flange 4b. In the axial direction, the outer casing 4a comprises at least partially external threads 4 so that the screw 1 can be screwed into a detail 17 comprising a hole 21. The part 17 can be of wood, metal or polymeric material, e.g. plastic. The design of the threads, i.e. pitch, height, width and length of the outer casing can be varied based on the material from which the screw 1 is to work.

The outer flange 4b is formed around the center of rotation in the first end surface 12a with a recess 5 in axial joint X. The recess 5 comprises a fitting part 10 formed with a cross-sectional radial joint R which is suitable for fitting a tool, and may be .ex. a triangular, square, pentagonal, hexagonal, or other suitable cross-section to allow a good engagement between the tool and the fitting part. The fitting part 10 is intended to receive a tool (not shown) with a corresponding design as the fitting part 10, e.g. triangular, square pentagonal, hexagonal, or other suitable shape to obtain a good grip between the tool and the fitting part 10. The recess 5 may after the fitting part 10, in the direction of the first end surface 12a, comprise a third section 11 intended to facilitate insertion of a tool to be fitted into the fitting part 10. The third section 11 can be omitted and the fitting part 10 then extends from the bottom of the recess 5 to the first end surface 12a. According to another example (not shown), the fitting part consists of an elevation in the first end surface in the axial joint.

The elevation here replaces the recess and the fitting part is designed to be embraced by a tool. The fitting part / elevation may, like the recess, comprise a section with specially designed geometry that fits the tool.

The screw 1 is arranged to be screwed into the above-mentioned part by means of the tool in the fitting part 10 in that the screw 1 is arranged to rotate in a direction of rotation R1 about a center axis C1 extending in axial direction X.

The direction of rotation R1 is defined in the figure as a clockwise rotation due to the fact that the cylindrical unit 3 is right-handed. In the case of a left-handed cylindrical unit 3, the direction of rotation R1 is thus counterclockwise. The first end surface 12a has a radial extension R which exceeds the radial extension 4a of the outer casing 4a.

The machining surface 12c extends from the edge portion 12b to the outer casing 4a. The machining surface 12c has an angle relative to a normal Ng to the outer casing 4a which depends on a number of factors which will be reported below.

The machining surface 12c may be conical, i.e. include straight lines, or may be convex, i.e. include curved lines (see Figure 2a). An advantage of a conical surface compared to convex is that the amount of material that needs to be transported away when the machining surface 12c acts against a detail is minimal.

Figure 1 shows that the outer flange 4b comprises through holes 31 extending from the first end surface 12a through the outer flange 4b to the machining surface 12c. Thus, in the first end surface 12a there are first openings 32 for respective holes 31 and in the machining surface 12c there are corresponding second openings 33. The holes 31 are each arranged in the outer flange 4b at an angle q> 1 and N to the first end surface 12a. The angle cp1 is measured against the normal N substantially in the direction of rotation, i.e. in a direction substantially coinciding with a normal to a radius taken in the first end face 12a. The angle cp2 is measured against the normal N substantially in radial direction R, i.e. in a direction substantially coinciding with the radius taken in the first end face 12a. The angles are thus substantially perpendicular to each other in the plane constituted by the first end surface 12a.

Figure 1 shows that the machining surface 12c comprises recesses 34 arranged to an extent substantially in the direction of rotation R1 of the screw 1. Each recess 34 extends in the direction of rotation R1 from the front edge 35a of the second opening 34 to a position before the rear edge 35b of the next second opening 34. The length of the recess and its geometric design depend on a number of factors, namely the angles cp1, cp2 and CD, as well as the material of the part to which the screw 1 is to be used.

The angle The angle depends, among other things, on the material in the screw because the edge part 12b must not bend due to the goods weakening too much when the holes 31 are taken up. Experiments have shown very good results for wood then and especially good results as The angle cp2 depends on the material of the part and can vary from 0 ° to about i30 °. The angle depends, among other things, on the material in the screw because the edge part 12b must not bend due to the goods weakening too much when the holes 31 are taken up. Experiments have shown very good results for wood as the Angle CD depends on how much material is to be transported away. The smaller the angle, the less material to transport away. The angle C1> also depends on the ability of the cutting edge 35 to act. The larger the slope, the better the cutting edge 35 can work. Both of these factors depend on the material in the part 17. A soft material makes it possible to have a large angle CD because the large amount of material to be transported away via the holes 31 can be easily processed by the cutting edge. A hard material gives a desire that as little material as possible should be removed, i.e. a slight angle, but the cutting edge 35 must then be able to appear sharp. The angle CD must thus be optimized depending on the choice of material of the part 17. The angle must also be optimized towards the pitch angle of the threads 4, i.e. the number of threads per unit length, since the pressure of the machining surface 12c against the material in the part 17 depends on the ratio between the pitch angle and the angle C1> and the amount of material that can be transported away. At a high pitch angle, the screw 1 moves a longer distance in the axial direction than at a low pitch angle. Thus, at a high pitch angle, more material per unit time must be transported through the holes 31 so that the pressure does not become too great so that the screw cannot be screwed in. Here there is then a desire that as little material as possible should be removed because the angle CD should be small. The amount of material that can be carried away through the holes 31 10 15 20 25 532 292 10 also depends on the diameter of the holes 31 and the angles cpi and since the angles (pi and cp2 de also of the design of the recesses 34, ie depth and length, and the angle of the recesses 34 towards the other openings 33. Experiments have shown very good results for wood when <1) is about 10 ° -50 °, and especially good results when <0 is approx. 25-35 °. At these angles on gives good results without the presence of the above-mentioned recesses 34 in the machining surface 12c.

The trailing edge 35b constitutes a cutting edge (hereinafter referred to as cutting edge 35b) intended to machine, e.g. by cutting, reaming, scraping, or any other suitable working method, in the part 17 in which the screw is used.

The screw 1 is arranged to be screwed into the hole 21 during assembly in the part 17 in such a way that the machining surface 12c processes the part 21 by the cutting edge 35b processing the material in the part in such a way that the material detaches from the part and is transported out via the holes 31.

According to an example of the invention, each recess 34 extends so far towards the corresponding hole 31 that the leading edge 35a becomes lower than the trailing edge 35b. The second opening 33 thus does not lie in a plane, but has a surrounding edge which changes in height in axial direction and where the rear edge 35b is higher than the front edge 35a. The recesses 34 give an improved property of the machining surface at small angles and are necessary then = 0 for the rear edge 35b to be able to form a cutting edge. When the angle (D is approx. 20-45 °, the recesses are not necessary, but the rear edge 35b of the second opening 33 nevertheless forms a cutting edge due to the machining surface 12c acting in a helical movement when the screw is screwed into the part. The helical movement The difference between the width of the first end face 12a and the radial width of the outer shell 4a depends on a number of factors: namely the number of holes 31; size of the holes 31; cp2 and fb, as well as the material of the part to which the screw 1 is to be used, and the choice of thickness of the goods between the edge part 12b and the holes 31. In figure 1 the edge part 12b has an extension in axial joint X, i.e. thickness, to meet the first end surface 12a without any edge part 12b, i.e. the thickness of the edge part 12b is zero, or at least a very thin edge part. However, the edge part must be so thick that the edge part 12b does not bend the screw 1 is screwed into the part 17 and the edge part comes into contact with the part. The choice of material of the screw 1 and the material of the part 17 are thus decisive for the thickness of the edge part 12b. In Figure 1, the edge part 12b is circular, which has proved to be advantageous when the screw 1 is screwed into the part 17 so that the edge part 12b abuts the part 17 and processes the part 17, since the material of the part does not chip, at least in the case of wood. When the holes 31 transport the material away from below the machining surface, the edge part 12b can compress the material in the part 17 into a smooth and circular recess. The circular edge portion 12b together with the distance between the holes 31 is a parameter to be considered in order to achieve a depression without fl icing.

Figure 1 shows in the part 17 with dashed line 36 that the part 17 comprises a recess 37. The recess is a result of the screw being screwed into the hole 21 in the part 17, the machining surface 12c through the cutting edges having machined away material from the part 17, which material then has transported away from the part 17 via the holes 31. Figure 1 shows that the outer flange 4b comprises seven holes 31, but the outer flange can comprise both more and fewer numbers of holes 31, e.g. a total of one hole or 14 holes, depending on the material of the outer flange 4b, the size of the holes 31, the size of the recesses 34, (91, to which the screw 1 is to be used. A compromise may need to be made regarding the number of holes, but the goal is to obtain a good machining ability and material transport away from the part 17, as well as a strength of the outer flange 4b which allows machining without the outer flange folding.

The holes need not be round, but may be oval or have any other suitable geometry. Figure 1 shows that the screw 1 comprises a cape 39 comprising a second end surface 40 and a jacket surface 41 whose circumference decreases in the direction from the cytin-shaped unit 3 towards the second end surface. 40. Cape 39 may be conical or tortuous and may be pointed or obtuse. By blunt is meant that the other end surface is flat or curved. The first end face 12a and the second end face define the screw in axial joint X, i.e. they are on opposite sides of the screw.

In the cases where the part is pre-drilled, the jacket surface 41 can be substantially eliminated, the second end surface 40 constituting the end of the cylindrical unit.

Fig. 2 schematically shows a cross-section along the line A-A in Fig. 1 of a screw according to a first example of the invention. Figure 2 shows that the machining surface 2c has a substantially conical geometry, i.e. straight cross-sectional profiles.

Figure 2 shows that the recess 5 after the fitting part 10 comprises the third section 11 with a substantially circular cross-section. Figure 2 shows: L1 = length of the guide section 9 in joint; L2 = the distance between the guide portion 9 and the first end surface 12a of the cylindrical unit 3. L2 axial and includes the length L1 of the guide portion; D1 = diameter of the guide portion 9.

Fig. 2a schematically shows a cross-section along the line A-A in Fig. 1 of a screw according to a second example of the invention. Figure 2 shows that the machining surface 2c has a substantially convex geometry, i.e. curved cross-sectional profiles.

The machining surface 2c can also be convex or a mixture of convex, concave and conical geometry. Fig. 2b schematically shows a cross-section along the line A-A in Fig. 1 of a screw according to a third example of the invention. The angle cp2 is measured against the normal N substantially in radial direction R, i.e. in a direction substantially coinciding with the radius taken in the first end face 12a. The angle detail and can vary from 0 ° to about 1300. The angle depends, among other things, on the material in the screw because the edge part 12b must not fold due to the goods being weakened too much when the holes 31 are taken up. Experiments have shown very good results for wood then and about 25 °, but as mentioned earlier, the angle can vary.

Fig. 2c schematically shows a side view according to an embodiment of a screw according to one of the ur gures 1-2b. The above description will be applied to Figures 2c-2f. The angle cp2 is equal to zero, Fig. 2d schematically shows a side view of figure 2c seen from the other side of the housing.

Fig. 2e schematically shows a side view according to an example of a screw according to one of Figs. 1-2b. The angle f.p1 is in fi gur 2e equal to zero and the angle cp2 is equal to zero.

Fig. 2f schematically shows a side view according to an example of a screw according to one of the 1-2 gures 1-2b. The angle cp1 is in 2 gur 2f equal to zero and the angle cp2 is equal to zero. Figure 2f shows that the machining surface 2c has no recesses 34, but this is only possible when the angle CD is greater than zero.

The machining surface Zc may lack recesses 34 in all embodiments described in connection with Figures 1-2e, provided that the angle CD is greater than zero. In figure 2f the holes 31 are displaced in radial joint R. The holes 31 can be displaced in radial joint R in all embodiments described in connection with figures 1-2e.

Fig. 29 schematically shows a side view according to an example a screw according to one of Figs. 1-2b. Angle 532 252 14 with zero. Figure 2f shows that portions 38 of the edge portion 12b have been removed adjacent the holes 31.

Fig. 3 schematically shows a side view of a screw according to the present invention comprising a cutting tip 39. The tip 39 comprises a cutting edge 42 for forming a hole in the part (17) upon rotation of the screw 1.

The screw may comprise a continuous channel from the cape channel for transporting material away from channel for transporting material from the cape 39 to the first end surface 12a.

Claims (10)

10 15 20 25 532 292 15 PATENT REQUIREMENTS Screw (1) comprising a cylindrical unit (3) with an at least partially threaded (4) outer casing (4a) and an outer flange (4b) comprising a first end surface (12a) with an extension in radial joint (R) larger than the outer casing (4a), the outer flange (4b) comprising an edge portion (12b) defining the outer flange (4b) in radial direction (R), the outer flange (4b) comprising a fitting portion (10) formed with a cross section in radial direction (R) suitable for fitting a tool to rotate the cylindrical unit, characterized in that the outer flange (4b) comprises a machining surface (12c) extending from the edge portion (12b) to the outer casing (4a). ), the machining surface (12c) being arranged at an angle <1) relative to a normal (Ng) to the outer casing (4a), the outer edge (4b) comprising through holes (31) extending from the first end surface (12a) through the outer flange (4b) to the machining surface (12c), the first end surface (12a) comprises first openings (32) for respective holes (31) and wherein the machining surface (12c) comprises corresponding second openings (33), each second opening (33) being defined by a leading edge (35a) and a trailing edge (35b) comprising a cutting edge (35b) arranged to machine a surface of a part (17) in which the housing (2) is intended to be screwed in, the hole (31) being arranged to transport away material which the cutting edge (35) has worked away from the part (17) . Screw (1) according to Claim 1, characterized in that the machining surface (12c) is symmetrically and / or asymmetrically convex and / or symmetrically or asymmetrically concave. asymmetrically conical, or symmetrical or Screw (1) according to one of the preceding claims, characterized in that the holes (31) are each arranged in the outer flange (4b) at an angle relative to a normal N to the first end surface (12a), the angles being substantially perpendicular to each other. 10 15 20 25 532 292 16 Screw (1) according to any one of the preceding claims, characterized in that the machining surface (12c) comprises recesses (34) arranged with an extension substantially in a direction of rotation (R1) of the housing (2), each recess (34) extending in the direction of rotation (R1) from the leading edge (35a) of the second opening (34) to a position before the trailing edge (35b) of the next second opening (34). Screw (1) according to claim 4, characterized in that the recesses (34) extend so far towards the holes (31) that the leading edge (35a) becomes lower than the trailing edge (35b). Screw (1) according to claim 4 or 5, characterized in that the angle Screw (1) according to one of the preceding claims, characterized in that the edge part (12b) has a thickness which allows the edge part (12b) to resist folding when the screw (1) is screwed into the part (17) in such a way that the edge part (12b ) comes into contact with the part, without the edge part (12b) being able to abut against the part (17) and machine the part (17) when the screw (1)) is screwed into the part (17). Screw (1) according to claim 7, characterized in that, when the holes (31) transport the material away from under the machining surface (12c), the edge part (12b) can compress the material in the part (17) into a smooth and circular recess. Screw (1) according to any one of the preceding claims, characterized in that the screw (1) comprises a point (39) comprising a second end surface (40) and a jacket surface (41) whose circumference decreases in the direction of the cylindrical unit (3) towards the end surface (40). Screw (1) according to claim 9, characterized in that the cap comprises a cutting edge (42) for forming a hole in the part (17) upon rotation of the screw 1.