TWI733584B - Screw with cutting teeth - Google Patents

Abstract

A screw with cutting teeth includes a shank and at least one thread. The shank includes a front section, a rear section spaced from the front section along a longitudinal axis of the shank, and an intermediate section between the front and rear sections. A head portion is formed at an upper end of the rear section. The front section has a circular cross section, and at least one tooth is provided on the outer circumference of the front section. The thread is spirally formed on the shank and includes a plurality of thread convolutions. A pitch is defined between two adjacent thread convolutions. The tooth extends at least one pitch along the longitudinal axis of the shank and is located between two adjacent thread convolutions of the front section.

Description

Screw with cutting protruding teeth

The invention relates to a screw suitable for wooden or cement workpieces, in particular to a screw with cutting protruding teeth.

For wooden workpieces including furniture, decoration and construction, wood or composite wood made of plastic resin and wood chips are mixed and pressurized. The connection between wooden workpieces is usually locked by screws. Conventional screws generally include a rod body and a thread wound on the rod body. The thread is screwed into two workpieces, so that the two workpieces can be connected by screws. However, when the material of the wooden workpiece is very hard, the thread of the conventional screw will generate considerable frictional resistance during the reaming process of screwing into the workpiece, which is laborious and time-consuming in operation, and is likely to cause the workpiece to crack. Furthermore, when the screw is applied to a hard cement workpiece, it also has the problem of laborious operation and slow screwing speed.

For this reason, the main purpose of the present invention is to provide a screw with cutting protruding teeth, which can be quite smooth during the reaming process of screwing into the workpiece, and has high screwing speed, labor-saving operation, and does not reduce the screw and The effect of the bonding force between the workpieces has the advantages of manufacturing convenience and cost reduction at the same time.

The screw of the present invention includes a rod body and a first thread. The rod body includes a front section, a rear section, and an intermediate section between the front section and the rear section. The upper end of the rear section forms a head, and the front section Separate from the rear section on a longitudinal axis of the rod body, the front section has a circular transverse section and at least one protruding tooth is provided on the outer periphery of the front section. The first thread is spirally wound around the front and middle sections of the rod body and includes a number of threads. A pitch is defined between two adjacent threads, and the crest of each thread is between the top of the thread and the periphery of the shaft. Define a first tooth height. The at least one protruding tooth system extends along the longitudinal axis of the rod by at least one pitch and is located between two adjacent threads of the first thread. The crest of the at least one protruding tooth and the periphery of the rod body are defined A second tooth height, the second tooth height is smaller than the first tooth height of the thread.

In one embodiment, the second tooth height is 40-60% of the first tooth height.

In one embodiment, a plurality of protruding teeth are provided on the outer periphery of the front section, and each protruding tooth extends along the longitudinal axis of the rod body for a length of at least two pitches, and the upper end and the lower end of each protruding tooth are respectively connected to a corresponding screw. Teeth coincide.

In one embodiment, three protruding teeth separated by about 120 degrees are arranged on the outer periphery of the front section, a drill tail end extends from the lower end of the front section, and the transverse section of the drill tail end is generally triangular and has three angles, The three protruding teeth and the three corners of the drill tail end are arranged staggered.

In one embodiment, the middle section has a circular cross-section and defines a middle section rod diameter, the rear section defines a rear section rod diameter, and the outer diameter of the rear section is slightly larger than the outer diameter of the middle section. The top of the protruding tooth defines an outer diameter of the protruding tooth, the outer diameter of the protruding tooth is larger than the rod diameter of the middle section and slightly smaller than the rod diameter of the rear section. The rear section is provided with a plurality of separated convex ribs, the plurality of convex ribs define an outer diameter of the convex rib, and the outer diameter of the convex rib is larger than the rod diameter of the rear section.

In one embodiment, the rod is further provided with a second thread, the second thread includes a plurality of threads, the threads of the second thread are separated from the threads of the first thread, and the threads of each second thread A third tooth height is defined between the crest of the screw tooth and the periphery of the rod body. The third tooth height is smaller than the first tooth height and approximately equal to the second tooth height.

In one embodiment, the thread of the first thread is an asymmetric thread and has an upper cutting surface and a lower cutting surface. The upper cutting surface and a horizontal axis define a first included angle, and the first included angle is between 3-15 Between degrees, the lower cutting surface and the horizontal axis define a second included angle, and the second included angle is between 7-35 degrees and greater than the first included angle.

The other objectives, advantages and features of the present invention will be understood from the detailed description of the following preferred embodiments with reference to the accompanying drawings.

The specific embodiments are only examples but not for limitation, and the preferred structure content of the present invention is described as follows with reference to the accompanying drawings:

1 to 6, there is shown a screw 10 constructed in accordance with the first embodiment of the present invention. The screw 10 includes a rod body 12 including a front section 14, a rear section 16, and located between the front section 14 and the rear section 16.的一中段18。 One middle paragraph 18. The front section 14 and the rear section 16 are separated on a longitudinal axis X of the rod body 12. In this embodiment, the lower end of the front section 14 extends a pointed cone-shaped drill end 20, and the transverse section of the drill end 20 is generally triangular and has three angles 21 (see FIG. 6). The screw 10 with a drilled end 20 is suitable for screwing into a workpiece such as wood. In a feasible embodiment, the lower end of the front section 14 does not extend the tail end.

The rear section 16 defines a rear section rod diameter D1 which is slightly larger than a middle section rod diameter D2 defined by the middle section 18. The upper end of the rear section 16 has a head 22, and the upper surface of the head 22 has a bearing hole 24 for inserting a tool such as a screwdriver (not shown). The screw 10 further includes a first thread 26. The first thread 26 is helically arranged on the rod body 12 and includes a plurality of threads 28. There is a pitch P between two adjacent threads 28. A first tooth height (H1) is defined between the tooth crest and the outer periphery of the rod body 12. In this embodiment, the first thread 26 extends from the drill end 20 to the middle section 18, and each thread 28 is a symmetric thread, and the thread angle (C) of each thread 28 is between 20-80 degrees ( See Figure 2). In a feasible embodiment, the first thread 26 may extend from the tail end 20 to the rear section 16, and each thread 28 may be an asymmetric thread.

A feature of the present invention is that the front section 14 of the screw 10 has a circular cross section (see FIG. 5), and at least one protruding tooth 30 is provided on the outer periphery of the front section 14. In a preferred embodiment, the front section 14 One to eight protruding teeth 30 are provided on the outer periphery of 14. In this embodiment, three separated protruding teeth 30 are provided on the outer periphery of the front section 14. Each protruding tooth 30 extends along the longitudinal axis X of the rod body 12 by at least a length of the pitch P and is located in two adjacent ones. Between the threads 28, the upper end 32 and the lower end 34 of each protruding tooth 30 are overlapped with a corresponding thread 28, respectively. A second tooth height (H2) is defined between the crest of each protruding tooth 30 and the outer periphery of the front section 14, and the second tooth height (H2) is smaller than the first tooth height (H1) of the screw thread 28. In a preferred embodiment, the second tooth height (H2) is 40-60% of the first tooth height (H1). When the second tooth height (H2) is too small (less than 40% of the first tooth height (H1)), the reaming function will not be achieved, and the screwing resistance cannot be reduced, and the operation will be more laborious; when the second tooth is high When (H2) is too large (greater than 60% of the first thread height (H1)), the tensile strength after screwing in the screw will be insufficient.

In this embodiment, the transverse section of each protruding tooth 30 is zigzag and extends along the longitudinal axis X of the rod 12 for a length of three pitches (as shown in FIG. 3, each protruding tooth 30 is in four consecutive adjacent The threads 28 extend in a straight line, and the axial length L of the protruding teeth 30 extending on the front section 14 is three pitches P). In a feasible embodiment, the axial length L of the protruding teeth 30 extending on the front section 14 can be adjusted according to the overall length of the rod body 12, and is not limited to three pitches (P). Furthermore, the three protruding teeth 30 are separated by about 120 degrees in the peripheral direction of the rod body 12, and are arranged in a staggered configuration with the three corners 21 of the drill end 20 (see FIG. 6). In a feasible embodiment, the three protruding teeth 30 and the three corners 21 of the drill end 20 are aligned on the longitudinal axis X.

In this embodiment, the rod diameter D1 of the rear section is greater than the rod diameter D2 of the middle section, and the middle section 18 and the front section 14 have the same outer diameter and have a circular cross section. Furthermore, the top of the protruding teeth 30 provided in the front section 14 defines a protruding tooth outer diameter D3 (see FIG. 3), which is larger than the middle section rod diameter D2 and slightly smaller than the rear section rod diameter D1. In addition, in this embodiment, the rear section 16 is provided with a plurality of separated ribs 36, the plurality of ribs 36 define a rib outer diameter D4, the rib outer diameter D4 is greater than the rear section rod diameter D1 to facilitate the rear section 16 to be screwed into the workpiece Inside.

In the implementation of the screw 10 of the first embodiment of the present invention, the drill end 20 is inserted into a workpiece such as a wooden board, and a hand tool or an electric tool (not shown) is inserted into the bearing hole 24 of the head 22 to rotate the screw 10 , So that the first thread 26 is screwed into the workpiece. When the first thread 26 is screwed into the reaming process of the workpiece, the protruding teeth 30 provided on the front section 14 can assist the first thread 26 to cut the workpiece, so that the resistance of the screw 10 in the locking direction can be effectively reduced, thereby improving the screwing Speed; in addition, the convex teeth 30 provided on the front section 14 can crush and quickly disperse the waste generated by the screw 28 cutting the workpiece to reduce the resistance when the debris is discharged, so that the screw 10 itself will not break and the workpiece will not break. Furthermore, since the transverse section of the front section 14 of the screw 10 is circular, it is more convenient to form the protruding teeth 30 around the rod body 12, which has the effect of convenient manufacturing and cost reduction.

Figures 7 and 8 show a screw 10 according to a second embodiment of the present invention. In this embodiment, the screw 10 further includes a second thread 38. The second thread 38 is provided on the upper end 32 of the protruding tooth 30 and the rear section of the rod body 12. A plurality of threads 40 are included between 16 and the plurality of threads 40 are separated from the threads 28 of the first thread 26. A third tooth height (H3) is defined between the crest of each thread 40 and the outer periphery of the rod body 12. The third thread height (H3) is smaller than the first thread height (H1) of the thread 28 and is approximately equal to the convex thread The second tooth height of 30 (H2). In practice, when the middle section 18 of the screw 10 is screwed into the work piece, the screwing of the second thread 38 can enhance the reaming effect, so that the middle section 18 of the screw 10 can be screwed into the work piece more smoothly. Furthermore, each thread 28 is an asymmetric thread, so as to reduce the screwing resistance of the screw 10 and improve the pull-out resistance. Each thread 28 has an upper cutting surface 42 and a lower cutting surface 44. The upper cutting surface 42 and a horizontal axis define a first included angle (B1), the first included angle (B1) is between 3-15 degrees, and the lower cutting surface 44 A second included angle (B2) is defined with the horizontal axis, and the second included angle (B2) is between 7-35 degrees and greater than the first included angle (B1). In a preferred embodiment, the thread angle of the first included angle (B1) plus the second included angle (B2) is between 10-50 degrees, preferably between 25-40 degrees.

The above are detailed descriptions and drawings of the preferred embodiments of the present invention, and are not intended to limit the present invention. All the scope of the present invention should be subject to the following patent scope, and the spirit of the patent scope and similarly modified embodiments Both and similar structures should be included in the present invention.

10: Screw

12: Rod body

14: front section

16: back section

18: middle section

20: Drill the tail end

21: corner

22: head

24: Socket

26: The first thread

28: Thread

30: protruding teeth

32: upper end

34: bottom

36: convex rib

38: second thread

40: Thread

42: Upper cutting surface

44: lower cutting surface

B1: The first angle

B2: The second included angle

C: Thread angle

D1: Rear rod diameter

D2: Middle section rod diameter

D3: Outer diameter of convex teeth

D4: Outer diameter of convex rib

H1: first tooth height

H2: second tooth height

H3: third tooth height

L: axial length

P: pitch

X: longitudinal axis

Fig. 1 is a perspective view of a screw according to an embodiment of the present invention.

Fig. 2 shows a partial front view of the screw of Fig. 1;

Fig. 3 is a longitudinal sectional view taken along line 3-3 of Fig. 1;

Figure 4 is a transverse cross-sectional view taken along line 4-4 of Figure 2;

Figure 5 is a cross-sectional view taken along line 5-5 of Figure 2;

Figure 6 is a cross-sectional view taken along line 6-6 of Figure 2;

Fig. 7 is a front view of a screw according to another embodiment of the present invention.

Fig. 8 is a cross-sectional view taken along line 8-8 of Fig. 7;

10: Screw

12: Rod body

14: front section

16: back section

18: middle section

20: Drill the tail end

22: head

26: The first thread

28: Thread

30: protruding teeth

36: convex rib

D1: Rear rod diameter

D2: Middle section rod diameter

D3: Outer diameter of convex teeth

D4: Outer diameter of convex rib

L: axial length

P: pitch

X: longitudinal axis

Claims (8)

A screw with cutting protruding teeth, comprising: a rod body including a front section, a rear section, and a middle section between the front section and the rear section, the upper end of the rear section forms a head, the front section and the rear section Separate on a longitudinal axis of the rod body, the front section has a circular transverse section and at least one protruding tooth is provided on the outer periphery of the front section; and a first thread which is spirally wound around the rod body The front section and the middle section include a plurality of threads, a pitch is defined between two adjacent threads, and a first tooth height is defined between the crest of each thread and the periphery of the rod body, wherein the at least one protruding tooth At least one pitch extends along the longitudinal axis of the rod body and is located between two adjacent threads of the first thread. A second tooth height is defined between the crest of the at least one protruding tooth and the periphery of the rod body , The second thread height is smaller than the first thread height of the thread, wherein the rod body is further provided with a second thread, the second thread includes a plurality of threads, the thread of the second thread and the thread of the first thread The threads are separated, and a third tooth height is defined between the crests of the threads of each second thread and the periphery of the rod body. The third tooth height is smaller than the first tooth height and approximately equal to the second tooth height. According to the first item of the scope of patent application, the screw with cutting protruding teeth, wherein the second tooth height is 40-60% of the first tooth height. According to the first item of the scope of patent application, the screw with cutting protruding teeth is provided with a plurality of separated protruding teeth on the outer periphery of the front section, and each protruding tooth extends at least two pitches in length along the longitudinal axis of the rod. The upper and lower ends of the teeth are respectively coincident with a corresponding thread. The screw with cutting protruding teeth according to item 3 of the scope of patent application, wherein the outer periphery of the front section is provided with three protruding teeth separated by about 120 degrees, the lower end of the front section extends a drill tail end, and the transverse section of the drill tail end It is generally triangular and has three corners, and the three protruding teeth are arranged staggered with the three corners of the drill tail end. According to the first item of the scope of patent application, the screw with cutting protruding teeth, wherein the middle The section has a circular cross-section and defines a middle section rod diameter, the rear section defines a rear section rod diameter, and the outer diameter of the rear section is slightly larger than the outer diameter of the middle section. According to the 5th item of the scope of patent application, the screw with cutting protruding teeth, wherein the top of the protruding teeth defines an outer diameter of the protruding teeth, the outer diameter of the protruding teeth is larger than the diameter of the middle section and slightly smaller than the diameter of the rear section. According to the sixth item of the scope of patent application, the screw with cutting protruding teeth, wherein the rear section is provided with a plurality of separated protruding ribs, the plurality of protruding ribs define an outer diameter of the protruding rib, the outer diameter of the protruding rib is larger than the rod diameter of the rear section. The screw with cutting protuberance according to the first item of the scope of patent application, wherein the thread of the first thread is an asymmetric thread and has an upper cutting surface and a lower cutting surface. The upper cutting surface and a horizontal axis define a first The included angle, the first included angle is between 3-15 degrees, the lower cutting surface and the horizontal axis define a second included angle, the second included angle is between 7-35 degrees and is greater than the first included angle.

Images