Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
  • F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
  • F16B35/06—Specially-shaped heads
  • F16B35/065—Specially-shaped heads with self-countersink-cutting means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B25/00—Screws that cut thread in the body into which they are screwed, e.g. wood screws
  • F16B25/001—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed
  • F16B25/0015—Screws that cut thread in the body into which they are screwed, e.g. wood screws characterised by the material of the body into which the screw is screwed the material being a soft organic material, e.g. wood or plastic
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
  • F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
  • F16B35/06—Specially-shaped heads

Definitions

• This disclosure relates to a screw for engagement with wood or similar composite material, such as a decking plane composite material.
• the screw comprises a countersunk head portion having a top side for accommodating a driving tool to rotate the screw and an essentially frusto-conical shaped lower portion.
• Screws are generally required to be driven into a working piece directly or into a pilot hole in the working piece.
• One common type of screw configured for tapping its own hole as it is driven into the working piece is a self-tapping screw.
• Self-tapping screws are fasteners that are designed to drill their own hole as they are screwed into the working piece.
• self-tapping screws are suitable for softer working pieces such as wood or composite materials, e.g. a decking plane material.
• wood screws and decking plane screws are available in several different shapes and sizes and are also available in numerous different head types.
• a so-called countersunk head portion which allows the head of the countersunk screw, when engaged with the working piece, to sit flush with or below the surface of the working piece.
• wood screws and decking plane screws are generally provided with a partially unthreaded shank below the head. The unthreaded portion of the shank is designed to slide through the top board (closest to the screw head) so that it can be pulled tight to the board to which it is being attached.
• some screw head portions are provided with ribs projecting outwardly from a lower part of the head portion or recesses having a cutting edge for cutting the fibres when the lower part of the head portion contacts the working piece upon rotation of the screw.
• US 5,683,217 Al discloses a self-countersinking screw including an inverted-conical head portion having an underside with a plurality of generally triangular recesses.
• Each one of the recess of the plurality of the generally triangular recesses comprises a planar trailing wall forming a linear cutting edge at the merger of the trailing wall with surface of the of the underside.
• An object of the present disclosure is to provide an improved cutting action of a screw for engagement with wood or similar composite material, such as a decking plane composite material. This object is at least partly achieved by the features of claim 1.
• the disclosure concerns a screw for engagement with wood or similar composite material, such as a decking plane composite material, by rotating said screw in a rotational direction around a rotational axis of the screw.
• the screw extends in an axial direction and comprises: a countersunk head portion having a top side for accommodating a driving tool to rotate the screw and an essentially frusto-conical shaped lower portion; a shank extending from the head portion to a point tip and having a threaded region;
• frusto-conical shaped lower portion comprises a cutting recess section having a trailing region as seen in the direction of rotation;
• the trailing region comprises a cutting edge having a first axial end point and a second axial end point defining an imaginary line.
• the imaginary line defines a positive cutting edge angle a relative to a plane AP.
• the plane AP extends in a radial direction, at least from the rotational axis to the first axial end point, and in the axial direction A.
• a screw with an improved cutting action of fibres such as wood fibres or fibres of the decking material.
• a countersunk- screw having an improved cutting action of the head portion.
• a countersunk-screw is adapted for being countersunk into the material.
• the screw is capable of removing the fibres from the material in an efficient and smooth manner, i.e. without risking a splitting of the wood material, composite material or the like as well as reducing the amount of fibres at engagement with and assembly of the screw to the working piece (e.g. a decking plane).
• the head portion is configured for cutting through the fibres and further pushing the fibres in a direction downwardly as opposed to an upward direction, which is typically the case with recesses having a negative cutting edge angle.
• the improved cutting action of the screw due to the positive cutting edge angle contributes to reduce the amount of fibres when the screw head portion meets the working piece at the engagement and assembly of the screw to the working piece, thus increasing the chances of having an overall improved end result with a remained finish or surface of the wood material.
• the positive cutting edge angle also contributes to direct the fibres of the material downwardly so that the fibres are pressed against the working piece and further consolidated between the working piece and the lowermost portion of the head portion of the screw. In this manner, it becomes possible to prevent that water from the outside, e.g. from rain, is accumulated and penetrated underneath the head portion of the screw.
• the screw may be inserted into the material with an insertion depth of about 4-7 mm, as defined between the top side of the screw and the surface of the decking plane.
• the cutting recess section is capable of accommodating fibres developed by the countersinking of the screw. It is to be noted that the cutting recess section typically can be further defined by an inner volume, defined by the surfaces of the cutting recess section and a nominal surface of the frusto-conical shaped lower portion extending in line with a circumferential surface of the frusto-conical shaped lower portion.
• the positive cutting edge angle a is in a range between 0 ⁇ a ⁇ 90 degrees.
• the positive cutting edge angle a is in a range between 2 - 45 degrees. More particularly, the positive cutting edge angle a is in a range between 3 - 25 degrees. Even more particularly, the positive cutting edge angle a is in a range between 5 - 15 degrees.
• the cutting recess section is disposed on a circumferential surface of the frusto-conical shaped lower portion.
• the cutting edge forms the intersection between the circumferential surface of the frusto-conical shaped lower portion and the trailing region of said cutting recess section.
• the cutting recess section is typically defined as a closed recess disposed on the circumferential surface of the frusto-conical shaped lower portion. That is, the surface extension of the cutting recess section on the circumferential surface of the frusto-conical shaped lower portion is defined by a closed contour including the cutting edge.
• the closed contour can be provided in several different manners.
• an axial extension of the cutting recess section is defined by opposite axial end points.
• the cutting recess section is defined by the first axial end point and the second axial end point. Accordingly, the cutting recess section is distinguished from a groove or channel extending entirely from the top side surface of the head portion to the shank of the screw.
• the top side of the head portion is free from the cutting recess section.
• the top side of the head portion defines a circumferential circular continuous outer edge.
• the top side of the head portion comprises a driving tool-receiving recess configured for cooperating with the driving tool.
• the driving tool is a torx-tool.
• other types of driving tools may also be conceivable in order to drive the screw into engagement with the material.
• the frusto-conical shaped lower portion comprises a plurality of cutting recess sections. Moreover, each one of the plurality of cutting recess sections having a corresponding trailing region, as seen in the rotational direction. Further, each one of the trailing regions comprises a corresponding cutting edge having corresponding first axial end point and second axial end point defining a corresponding imaginary line.
• the imaginary line defines a corresponding positive cutting edge angle relative to a corresponding plane, the corresponding plane extending in the radial direction, from the rotational axis to the corresponding first axial end point, and in the axial direction.
• the plurality of the cutting recess sections is distributed in a number of 2 ⁇ B
• the plurality of the cutting recess sections may even be distributed in a number greater than 16, e.g. 2 ⁇ B ⁇ 20, or even more than 20 cutting recess sections.
• the plurality of the cutting recess sections is uniformly distributed in around the circumference of the frusto-conical shaped lower portion.
• the length of the cutting edge is a function of the thread pitch of the thread region.
• the length of the cutting edge is a function of the thread lead of the thread region.
• the function is in one example such that the total length of all cutting edges, i.e. the sum of the length of each cutting edge, is adapted such that the entire part of the working piece being exposed to the circumferential surface of the head portion encounters a cutting edge.
• a very short thread pitch will lead to more rotations of the screw during the cutting phase and such a screw thus requires fewer and/or shorter cutting edges than a screw with a large thread pitch that will rotate fewer times during the cutting phase before the head portion of the screw is completely embedded in the working material.
• the cutting edge will have to be adapted to the thread lead in the same way as described above.
• the thread angle is also adapted to both the diameter and the pitch of the thread.
• the cutting recess section is further defined by a leading region.
• the leading region has a curved shape and provides the cutting recess section with a shape resembling an essentially inverted D-shape.
• the shape of the recess further facilitates an efficient move of the fibres of the material in a direction downwardly so that the fibres are pressed against the working piece and consolidated between the working piece and the lowermost portion of the head portion of the screw.
• the inverted D-shape of the cutting recess section further provides the largest volume possible for the cutting recess section in order to provide space for as much fibres as possible.
• a curved shape leading region in combination with the trailing region according to the above, further enhances the capability of transporting the fibres of the material downwards into the working piece.
• the final shape and maximum depth of the leading region are determined through simulations where the clamping force between the head portion and the material determines the maximum size of the leading region.
• the leading region may have slightly different appearances.
• the leading region is curved, providing the cutting recess section with a shape resembling an essentially inverted D-shape.
• the screw according to any one of the example embodiments, as mentioned above, is typically configured as a self-tapping screw.
• a self-tapping screw refers to a screw that can tap its own hole as it is driven into the decking plane material, wood material and/or the composite material.
• the self- tapping ability may typically be provided by the point tip that tapers to a gimlet point (in which no flute is needed).
• the screw may also be self-drilling, as is readily conceivable in the art.
• the cutting recess section typically defines an inner volume.
• the inner volume of the recess is typically, although not strictly necessary, defined by the surfaces of the cutting recess sections and a nominal surface of the truncated-cone shaped lower portion.
• the cutting edge is a straight cutting edge extending between the first axial end point and the second axial end point. In other example embodiments, the cutting edge is a curved cutting edge extending between the first axial end point and the second axial end point.
• thread typically refers to a ridge or a groove that winds around the screw shank.
• a thread can be defined by its thread profile, i.e. the thread and/or thread region is defined by a thread profile.
• the term "thread profile” refers to the cross- sectional shape, angle and pitch formed by the thread(s).
• various thread profiles may be used for the thread(s) of the screw.
• the shape of the thread profile for a given thread and/or thread region is typically selected depending on the type of installation and type of use of the screw.
• the thread is a helical ridge with a pitch.
• the pitch of a helix is the width of one complete helix turn as measured parallel to the axis of the helix.
• the pitch of the helix can be constant along the axial direction of the component.
• the screw may comprise a number of threads such as two, three or four congruent helices with the same axis, differing by a translation along the axis.
• the two, three or four congruent helices may have the same pitch.
• Fig. la is a side view of a screw according to an example embodiment of the present disclosure, which comprises a countersunk head portion having a top side for accommodating a driving tool to rotate the screw and an essentially frusto-conical shaped lower portion;
• Fig. lb is another side view of a screw according to an example embodiment of the present disclosure, which comprises a countersunk head portion having a top side for accommodating a driving tool to rotate the screw and an essentially frusto-conical shaped lower portion;
• Figs, lc-le illustrate further details of the countersunk head portion of the screw according to the example embodiment in figs, la and lb;
• Fig. 2 schematically illustrates a cross-sectional view B-B of the example embodiment of the screw in e.g. fig. la;
• Fig. 3 schematically illustrates a cross-sectional view A-A of the example embodiment of the screw in e.g. fig. la;
• Fig. 4 schematically illustrates a side view of another example embodiment of parts of a screw according to the disclosure
• Fig. 5 is a cross-sectional view of the screw in fig. 4, corresponding to the cross- sectional view A-A in fig. 3.
• Fig. 6a schematically illustrates a side view of a screw according to the present disclosure
• Fig. 6b schematically illustrates a cross-sectional view C-C of the screw in figure 6a.
• top For purposes of description herein the terms “top,” “under,” “upper,” “lower,” “bottom,” “upwardly,” “downwardly,” “longitudinal,” “inner,” “outer,” “radial,” “axial,” “circumferential,”, and derivatives thereof relate to the example embodiment of the disclosure as oriented in e.g. figs, la and lb.
• the disclosure mainly refers to screws for engagement with wood or similar composite material.
• One type of composite material is a decking plane composite material.
• the screw according to the example embodiments described in conjunction with the figs, la to 5 is a wood screw.
• the screw may be a so-called decking plane screw and the like.
• the exemplary embodiments of the screw may be installed in a composite material such as a decking plane material.
• the general constructions of screws according to the above are well known in the art, and the wide variation of types of such screws and their various optional components will therefore not be further described herein.
• the screw is a wood screw for engagement with a wood material.
• the screw is configured as a self-tapping screw.
• Fig. la illustrates a side view of the screw according to example embodiments when the screw has partly penetrated into the wood material
• fig. lb illustrates the screw in a position when the screw has penetrated further into the wood material forming a working piece 25 so as to engage with the working piece.
• the working piece is a decking plane material.
• the decking plane material may either be a wood material or any suitable composite material.
• the screw 10 in these examples is suitable for engagement with wood or similar composite material.
• One type of composite material is a decking plane composite material.
• the wood material is indicated by reference numerals 25.
• the screw 10 engages with the wood material 25 by rotating the screw in a rotational direction W around a rotational axis AC of the screw. As shown in the figures, the screw extends in the axial direction A. In addition, the screw extends in a radial direction R.
• the screw also has a circumferential extension in the circumferential direction of the screw.
• the screw comprises a countersunk head portion 12 having a top side 19 for accommodating a driving tool to rotate the screw and an essentially frusto-conical shaped lower portion 18.
• the top side is adapted for cooperating with the driving tool.
• the top side 19 of the head portion 12 comprises a driving tool- receiving recess 43 configured for cooperating with the driving tool, such as a torx-tool.
• a driving tool-receiving recess 43 is shown in fig. 2, which is a cross-sectional view along B-B in fig. la.
• the screw can be rotated by the driving tool in other possible ways in order to penetrate the screw into the working piece 25.
• the torx-tool is only one possible example of a number of various driving tool examples.
• the rotational axis AC of the screw in this example corresponds essentially to a centre line extending across the screw in the axial direction A.
• the essentially frusto-conical shaped lower portion of the head faces the shank.
• a circumferential surface 18a of the frusto-conical shaped lower portion 18 forms the transition between the top side 19 of the head portion 12 and the shank 14.
• the transition from the top side 19 of the head to the shank 12 is formed by an oblique circumferential surface of the frusto-conical shaped lower portion 18.
• the inclination of the oblique circumferential surface can be defined by an angle ⁇ .
• the angle ⁇ is illustrated in respect to the example embodiment described in conjunction to fig. 4.
• the angle ⁇ is in the range of 160 - 40 degrees. In this example, as shown in e.g. figs, la to le, the angle ⁇ is about 80 degrees.
• the angle ⁇ may of course vary depending on type of screw and type of working piece material.
• the screw comprises a shank 14 extending from the head portion to a point tip 11.
• the shank has a threaded region 15.
• the thread region 15 extends at least partly on the shank.
• the extension of the thread region on the shank is determined on the basis of the type of screw, use and installation of the screw as well as material of the working piece.
• the shank 14 further comprises an unthreaded shank portion arranged between the head portion and the thread region, as illustrated in fig. la.
• the thread region typically extends from a thread starting point at the tip 11 towards the head portion 12 of the screw.
• the thread region comprises the thread 15a.
• the thread 15a spirals along the screw 10 to permit the screw 10 to be screwed into the workpiece 25 through clockwise rotation, as seen from the head portion 12 towards the tip 11, around the rotational axis AC.
• the thread exhibits a thread lead.
• the thread exhibits a thread pitch.
• the thread region need not extend uninterrupted from the tip towards the head of the screw, but that the thread may be wholly or partly absent at one or several locations from a tread starting point at the tip to an end of the thread. In addition, the thread region may run entirely from the head portion to the tip of the screw.
• the frusto-conical shaped lower portion 18 comprises a cutting recess section 20 having a trailing region 22 as seen in the direction of rotation W.
• the cutting recess section 20 is capable of accommodating fibres developed by the countersinking of the screw.
• the cutting recess section 20 is configured for accommodating fibres or compressed materials from the workpiece when the head portion 12 of the screw 10 penetrates into the workpiece 25.
• the cutting recess section 20 is further defined by an inner volume 21.
• the inner volume is defined by the surfaces of the cutting recess section 20 and a nominal surface 18b of the frusto-conical shaped lower portion extending in line with a circumferential surface 18a of the frusto-conical shaped lower portion 18, as will be further described below in conjunction with fig. 2.
• the cutting recess section 20 is disposed on a circumferential surface 18a of the frusto-conical shaped lower portion 18.
• the trailing region 22 comprises a cutting edge 23.
• the cutting edge 23 has a first axial end point 41 and a second axial end point 42.
• the cutting edge is an essentially straight edge extending between the first axial end point and the second axial end point.
• the cutting edge 23 and the axial end points are further illustrated in figs, lc to le.
• fig. lc illustrates a side view of the screw 10 corresponding to the side view of the screw 10 in fig. la
• fig. Id illustrate another side view of the screw 10, in which the screw is rotated about 90 degrees in the rotational direction. In other words, the view of the screw 10 in fig.
• Id is orthogonal to the view of the screw 10 in fig. lc.
• Fig. le further illustrates a projection of the cutting edge 23 on a tangent plane TP, which coincides with the first axial end point 41.
• the tangent plane and fig. le will be further described below.
• the cutting edge having the first axial end point 41 and the second axial end point 42 can also be defined by an imaginary line Al. That is, the imaginary line Al extends between the first axial end point 41 and the second axial end point 42 of the cutting edge 23.
• the imaginary line Al is further illustrated in fig. le, which depicts a slightly curved cutting edge 23. In this figure, the cutting edge 23 is curved although extending between the first axial end point 41 and the second axial end point 42, while the imaginary line Al corresponds to a straight line defining the extension between the first axial end point 41 and the second axial end point 42 of the cutting edge.
• the curved cutting edge may form a convex curved edge or a concave curved edge with respect to the imaginary line Al, or an irregularly curved cutting edge. It should be readily appreciated, however, that the cutting edge 23 in some example embodiments, as shown in figs. la-Id, corresponds to the imaginary line Al. In other words, the cutting edge 23 is in this example embodiment a straight edge extending between the first and second axial end points 41 and 42.
• a trailing region 22 comprising a cutting edge 23 corresponding to a straight edge.
• the trailing region 22 here comprises a straight cutting edge 23 extending between the first axial end point 41 and the second axial end point 42.
• the first axial end point 41 and the second axial end point 42 define the imaginary line Al. That is, the imaginary line extends between the first and second axial end points 41, 42 of the cutting edge.
• the imaginary line Al defines a positive cutting edge angle a relative to a plane AP. With a positive cutting edge angle a is meant an angle as measured in a counter-clockwise direction from AP to Al.
• the plane AP extends in the radial direction R, from the rotational axis AC to the first axial end point 41.
• the plane AP extends in the axial direction A.
• the positive cutting edge angle a is obtained by projecting the cutting edge 23 on the tangent plane TP coinciding with the first axial end point 41 (see e.g. fig. Id).
• the tangent plane TP is further perpendicular to the plane AP and extends in the axial direction A and in a tangential direction T, as shown in fig. lc in combination with fig. Id.
• a projection of the imaginary line Al on the tangent plane TP defines the positive cutting edge angle a relative to the plane AP.
• the cutting edge 23 when the cutting edge 23 is a straight cutting edge extending between the axial end points 41, 42, the cutting edge 23 corresponds to the imaginary line Al, which defines the positive cutting edge angle a relative to the plane AP as mentioned above.
• the imaginary line AP defines the positive cutting edge angle a relative to the plane AP, as mentioned above and as illustrated in fig. le.
• the cutting edge 23 is radially inwardly inclined due to the shape of the frusto-conical shaped lower portion 18. In other words, as shown in e.g. fig.
• the cutting edge 23 is inwardly inclined from an upper first axial end point 41 and towards the centre line (axis of rotation) to the lower second axial end point 42, as seen in the radial direction R.
• the cutting edge 23 is configured for cutting the fibres when the frusto-conical shaped lower portion 18 makes contact with the surface of the working piece 25.
• the cutting edge 23 forms the intersection between the circumferential surface 18a of the frusto- conical shaped lower portion 18 and the trailing region 22 of the cutting recess section 20.
• the cutting edge 23 is configured to cut the fibres of the working piece material and direct the fibres downwardly so that the fibres are pressed against the working piece and further consolidated between the working piece and the lowermost portion of the head portion of the screw.
• one example advantage of the example embodiments of the present disclosure is to provide an improved cutting action of the fibres, while enabling that the fibres are pushed in a direction downwardly as opposed to an upward direction (typically referring to opposite directions along the axial direction A in e.g. figure la), which is typically the case with recesses having a negative cutting edge angle.
• the improved cutting action of the screw contributes to reduce the amount of fibres when the screw head portion meets the working piece at the engagement and assembly of the screw to the working piece, thus increasing the chances of having an overall improved end result with a remained finish or surface of the wood material.
• the positive cutting edge angle a may be above zero degrees but less than ninety degrees. That is, the positive cutting edge angle a may be in a range between 0 ⁇ a ⁇ 90 degrees. In this way, there is provided a cutting edge configured to provide an optimal cutting action, as described above.
• the size of the positive cutting edge angle a may be set to another angle depending on type of screw and/or type working piece. Thus, it should be conceivable that the value of the positive cutting edge angle a may be different for different screws and installations. In particular, the positive cutting edge angle a may be in a range between 2 - 45 degrees.
• the positive cutting edge angle a may be in a range between 3 - 25 degrees, even more particularly the positive cutting edge angle a may be in a range between 5 - 15 degrees. In some examples, the positive cutting edge angle a may be in a range between 4 - 10 degrees. In this example, as shown in e.g. fig. la, the positive cutting edge angle a is about 6 degrees.
• the cutting edge 23 may be a straight edge as long as the imaginary line Al defines the positive cutting angle with respect to the plane AP. However, in some example embodiments, the cutting edge 23 may be a curved edge as long as the imaginary line Al between the axial end points defines the positive cutting angle with respect to the plane AP.
• the cutting recess section 20 is typically a so called closed recess disposed on the circumferential surface 18a of the frusto-conical shaped lower portion 18. That is, the surface extension of the cutting recess section 20 on the circumferential surface of the frusto-conical shaped lower portion is defined by closed contour including the cutting edge 23.
• the term closed contour may refer to an uninterrupted circumferential edge. This type of contour can be provided in several different manners.
• the cutting recess section 23 is further defined by a leading region 28.
• the leading region here is curved providing the cutting recess section with a shape resembling an essentially inverted D-shape.
• the inverted D-shape is defined by the curved leading edge 30.
• the leading edge 30 defines the contour of the cutting recess section 20 together with the cutting edge 23.
• the cutting recess section 20 is typically formed by the leading region having the leading edge and the trailing region having the trailing edge (corresponding to the cutting edge).
• the axial extension 31 of the cutting recess section 20 is defined by the opposite axial end points 41, 42. As shown in fig. la (and also fig. 4), the axial extension 31 of the cutting recess section 20 is defined by the upper first axial end point 41 and the lower second axial end point 42. To this end, the top side 19 of the head portion 12 is free from any cutting recess section 20. In this manner, the cutting recess section 20 defines a closed void as seen from top side 19 of the screw 10. A cutting recess section 20 that does not extend into the top side of the head portion minimizes the risk of having fibres transported in the wrong direction, i.e. upwards (on the side above the top side as seen in the axial direction).
• Fibres that are pushed upwards often causes splits or cracks around the surface of the working piece (deck plane).
• fibres that are pushed upwards may often have a negative impact of the engagement of the screw with the working piece.
• the axial extension of the inverted D-shaped cutting recess section 20 is here defined by the upper first axial end point 41 and the lower second axial end point 42.
• the top side of the head portion defines a circumferential circular continuous outer edge 12a. Further details of the cutting recess section 20 are described below in conjunction with e.g. figs. 3 and 4.
• Fig. lb illustrates an example when the screw 10 is engaged with the working piece, such as a decking plane made in a wood material 25.
• the screw may be inserted into the material with an insertion depth of about 7 mm, as defined between the top side 19 of the screw and the surface of the decking plane.
• the provision of having a head portion with the essentially frusto-conical shaped lower portion facilitates hiding of the screw in the wood material. The effect of hiding the screw in the material is sometimes a desire when mounting decking planes.
• the screw 10 comprises a plurality of cutting recess sections 20. That is, the frusto-conical shaped lower portion 18 comprises a plurality of cutting recess sections 20.
• Each one of the plurality of cutting recess sections 20 comprises a corresponding trailing region 22, as seen in the rotation direction W. Further, each one of the trailing regions 22 comprises a corresponding cutting edge 23 having corresponding first axial end point 41 and second axial end point 42 defining a corresponding imaginary line Al.
• the imaginary line Al defines a corresponding positive cutting edge angle a relative to a corresponding plane AP.
• the corresponding plane AP extends in the radial direction R and in the axial direction A.
• the corresponding plane AP extends in the radial direction R, at least from the rotational axis AC to the corresponding first axial end point 41, and in the axial direction A (although not shown in figs. 2 and 3).
• each one of the corresponding recesses may include the features, examples and effects as mentioned in respect of the example of the screw and recesses described in figs, la-le.
• each one of the plurality of cutting recess sections 20 is here defined by a corresponding inner volume 21.
• the plurality of the cutting recess sections 20 is uniformly distributed in a number of 6 around the circumference of the frusto-conical shaped lower portion 18.
• each one of the cutting recess sections 20 extends essentially in the axial direction A. Further, each one of the cutting recess sections 20 is inclined inwardly towards the centre line (axis of rotation AC), as seen in the radial direction R. Analogously, each one of the cutting edges 23 extends essentially in the axial direction A. Further, each one of the cutting edges 23 is inclined inwardly towards the centre line (axis of rotation) as seen in the radial direction R.
• each one of the cutting recess section 20 has a trailing region 22 defined by a trailing surface 22A and a leading region 28 defined by a leading surface 28A.
• each one of the cutting recess section 20 has a bottom region 27 defined by a bottom surface 27A.
• the bottom region aligns the leading region with the trailing region.
• the bottom surface aligns the leading surface with the trailing surface.
• each one of the cutting recess sections 20 has an essentially triangular shaped cross section as seen in the circumferential direction and the radial direction.
• the essentially triangular shaped cross section is here defined by the leading surface, the bottom surface and the trailing surface.
• the trailing surface 22A (trailing region 22) essentially forms a right angle with respect to the circumferential surface 18a of the frusto-conical shaped lower portion 18.
• the cutting edge is configured to generate a cutting effect when being in contact with the working piece upon rotation of the screw as described above.
• the angle between the trailing surface 22A and the circumferential surface 18a may vary depending on desired type of cutting effect. In some examples, the angle between the trailing surface 22A and the circumferential surface 18a may be an acute angle, or even a slightly obtuse angle as long as a desired cutting effect is obtained by the cutting edge.
• each one of the cutting recess sections 20 is typically configured for containing fibres from the working piece.
• the maximum depth of the cutting recess section(s) 20 may be defined as the depth in the radial direction R, and further defined as the distance from the nominal circumferential surface 18b to the bottom surface 27A of the cutting recess section 20.
• the cross section B-B of the head portion 12 may comprise the driving tool-receiving recess 43 configured for cooperating with the driving tool, such as a torx-tool.
• the maximum depth of a cutting recess section 20 is essentially aligned in the radial direction with the maximum depth of the driving-tool receiving recess 43. This will be illustrated further below.
• the cutting recess section(s) 20 of the screw may typically be regarded as depression(s) rather than a screw with projections areas, i.e. areas extruding from the nominal circumferential surface of the frusto-conical lower portion of the head portion of the screw.
• leading surface 28A may have a somewhat curved contour, as illustrated in fig. 3. However, this design of the leading surface 28A is optional. Thus, in other example embodiments of the screw, the leading surface 28A may taper in an inclined manner towards the bottom surface 27A (bottom region 27).
• the dimensions of the cutting recess sections 20 are typically selected depending on the size and installation of the screw according to the example embodiments.
• the extensions of the cutting recess section 20 in the axial direction, the radial direction and in the circumferential direction are typically selected in view of the size of screw and the type of material of the intended working piece.
• the dimensions of the cutting recess sections 20 are typically the same for each one of the cutting recess sections 20 disposed on the screw 10.
• the distribution of the cutting recess sections 20 around the circumferential surface 18a is typically uniform, i.e. the distances between adjacent cutting recess sections 20 are constant around the circumferential surface 18a.
• a screw is provided essentially according to the example embodiments described in relation to figs, la-le and figs. 2-3, except that the frusto-conical shaped lower portion 18 of the head portion comprises one single cutting recess section 20.
• the screw comprises the countersunk head portion 12 having the top side 19 for accommodating a driving tool to rotate the screw and the essentially frusto-conical shaped lower portion 18. The top side is adapted for cooperating with the driving tool.
• the top side 19 of the head portion 12 may comprise the driving tool-receiving recess 43 configured for cooperating with the driving tool, such as a torx-tool.
• the screw comprises the shank extending from the head portion to the point tip.
• the shank has the threaded region 15.
• the thread region 15 extends at least partly on the shank.
• the frusto-conical shaped lower portion 18 comprises one cutting recess section 20 having the trailing region 22 as seen in the direction of rotation W.
• the cutting recess section 20 is disposed on the circumferential surface 18a of the frusto-conical shaped lower portion 18. As illustrated in figs.
• the trailing region 22 comprises the cutting edge 23 having the first axial end point 41 and the second axial end point 42 defining the imaginary line Al.
• the imaginary line Al defines the positive cutting edge angle a relative to the plane AP, as mentioned above.
• the screw as described in relation to figs. 4 and 5 may include similar functions and features as described with respect to the example embodiment in figs, la-lc and figs. 2 and 3.
• the example embodiment in figs. 4 and 5 may be mounted in a similar manner as the example embodiment in figs, la-lc and figs. 2 and 3.
• the number of cutting recess sections 20 may vary depending on type of screw and type of working piece material, and that the example described above in conjunctions with the figures are only two of several conceivable example.
• the number B of the cutting recess sections 20 may e.g. be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16.
• FIG. 6a schematically illustrates a side view of a screw 10 according to the present disclosure.
• the screw 10 in figure 6a is similar to the screw 10 of figure la.
• Fig. 6b schematically illustrates a cross-sectional view C-C of the screw 10 in figure 6a.
• the screw 10 comprises six cutting recess sections 20.
• the difference between the screw 10 in figure 6a and the screw 10 in figure la is that the cutting recess sections of the screw 10 in figure 6a are optimised to receive the maximum amount of material.
• the driving tool-receiving recess 43 is arranged to receive a torx-tool.
• the maximum depth of the cutting recess section(s) 20 may be defined as the maximum depth in the radial direction R, and further defined as the distance from the nominal circumferential surface 18b to the bottom surface 27A of the cutting recess section 20.
• the maximum depth of a cutting recess section 20 is essentially aligned or essentially coincides in the radial direction with the maximum depth of the driving-tool receiving recess 43 nearest to the respective cutting recess section.
• the rotational orientation of the cutting recess section(s) 20 is thus determined by the position(s) of the cutting recess section(s) 20 relative to the tool-driving recess 43.
• a further determinant of the size of the cutting recess section(s) 20 is that the smallest surface area of the cross section C-C of the head portion 12 is larger than the surface area of the cross section of the shank 14. This leads to that the shank 14 is the structurally weakest part of the screw 10, reducing the risk of shearing off the head portion 12 of the screw 10 from the shank 14. This relation also applies to a screw with fewer cutting recess sections 20 than shown in figure 6a, such as the screw 10 of figures 4 and 5.
• the axial length of the cutting edge is a function of the thread pitch of the thread region 15.
• the axial length of the cutting edge is a function of the thread lead of the thread region 15.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Wood Science & Technology (AREA)
• Connection Of Plates (AREA)
• Surgical Instruments (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=62018825

Family Applications (1)

Country Status (4)

Cited By (3)

Citations (4)

Family Cites Families (6)

• 2016
  • 2016-10-19 SE SE1651376A patent/SE541064C2/en unknown
• 2017
  • 2017-10-16 RU RU2019115116A patent/RU2744697C2/ru active
  • 2017-10-16 EP EP17862952.3A patent/EP3529505A4/en not_active Withdrawn
  • 2017-10-16 WO PCT/SE2017/051019 patent/WO2018074972A1/en active Search and Examination

Patent Citations (4)

Also Published As

Similar Documents

Legal Events