TWI683966B - Screw - Google Patents

Abstract

A screw includes a shank, a first thread, a second thread and a plurality of ribs. The shank includes a screwing portion, a head portion, and a straight rod portion between the screwing portion and the head portion. The straight rod portion includes a lower section adjacent to the screwing portion and an upper section adjacent to the head portion. The first thread is spirally formed on the screwing portion and the straight rod portion and includes a plurality of thread convolutions. The second thread is spirally formed on the screwing portion and spaced from the first thread. The ribs formed on the straight rod portion are spaced apart along a circumferential direction of the straight portion and located between adjacent two threads, and a bottom portion of each rib is adjacent to but spaced apart from a bottom end of the straight portion.

Description

Screw

The invention relates to a screw, in particular to a screw with a first thread and a second thread in a screw-in portion to improve the effect of expanding a hole.

FIG. 1 shows a screw 10 conventionally used for wooden boards, which includes a round rod body 12 and a thread 14 provided on the rod body 12. The rod body 12 includes a screw-in portion 16 and a head portion 17, and the screw-in portion 16 is provided with a tail groove 18. When the screw 10 is screwed into the two plates to be connected by the screw-in portion 16, the cutting groove 18 can cut the plate to expand the hole, so that the thread 14 can be smoothly screwed into the plate. However, the arrangement of the cutting groove 18 will not only increase the manufacturing process of the screw and increase the cost, but also cause the structural strength of the screw to decrease, resulting in the screw being easily broken during the locking process.

Therefore, the main object of the present invention is to provide a screw which has the effects of fast screwing into a plate and simple manufacturing, and the groove of the screw rod body is not provided, thus having the advantage of improving structural strength.

The screw according to the present invention includes a rod body, a first thread, a second thread and a plurality of ribs. The rod body includes a screw-in portion and a head portion separated in an axis direction, and a straight rod portion located between the screw-in portion and the head portion, the screw-in portion has a tip, and the straight rod portion includes a portion adjacent to the screw-in portion And the upper segment adjacent to the head. The first thread is provided on the rod body in a spiral shape and extends from the tip of the screw-in portion to the straight rod portion, the first thread includes a plurality of threads, and is defined between two adjacent threads One pitch. The second thread is spirally provided on the screw-in portion and is spaced apart from the first thread. The second thread includes a lower end adjacent to the tip but separated from the tip and a bottom end adjacent to the straight rod but The upper end separated from the bottom end. The plurality of convex ribs are provided on the lower section of the straight rod part separately along the circumferential direction of the straight rod part, each convex rib is located between adjacent two screw teeth, and the bottom of each convex rib is adjacent to the straight rod part But at a distance from the bottom end.

In an embodiment, the screw-in portion has a first length in the axial direction, and the second thread has a second length in the axial direction, and the second length is 30-75% of the first length.

In one embodiment, the height of each convex rib protruding from the straight rod portion is smaller than the tooth height of the screw thread, the plurality of convex ribs extend along the axis, and the bottom of each convex rib and the bottom end of the straight rod portion are at the The distance separating the axes is less than this pitch. The convex rib has a third length in the axial direction, and the third length is less than two pitches.

In an embodiment, the radial distance between the top of the convex rib and the central axis is greater than or equal to the radial distance between the crest of the second thread and the central axis.

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

10‧‧‧screw

12‧‧‧Pole

14‧‧‧Thread

16‧‧‧ Screw-in Department

17‧‧‧Head

18‧‧‧cut tail groove

20‧‧‧screw

22‧‧‧Pole

24‧‧‧First thread

26‧‧‧ Screw-in Department

28‧‧‧Head

30‧‧‧Straight rod part

31‧‧‧tip

32‧‧‧Bore

34‧‧‧Lower

36‧‧‧Upper

38‧‧‧Bottom

40‧‧‧screw

42‧‧‧Second thread

44‧‧‧Convex rib

46‧‧‧lower

48‧‧‧Upper

50‧‧‧Bottom

A‧‧‧Radial pitch

B‧‧‧Radial spacing

L1‧‧‧ First length

L2‧‧‧Second length

L3‧‧‧third length

P‧‧‧Pitch

X‧‧‧Axis

Figure 1 shows a schematic diagram of a conventional screw.

Fig. 2 is a perspective view of a screw according to an embodiment of the present creation.

Fig. 3 shows a plan view of the screw of Fig. 2.

4 is a cross-sectional view of the screw of FIG. 2.

Fig. 5 shows a partial enlarged view of the screw of Fig. 3.

FIG. 6 shows a cross-sectional view taken along line 6-6 of FIG. 5. FIG.

FIG. 7 shows a cross-sectional view taken along line 7-7 of FIG. 5. FIG.

The specific embodiments which are only examples but not for limitation are described below, and the preferred structural contents of the present invention are explained as follows with reference to the attached drawings:

2 to 7, a screw 20 according to an embodiment of the present invention is shown. The screw 20 includes a rod body 22 and a first thread 24 provided on the rod body 22. The rod body 22 includes a screw-in portion 26 and a head portion 28 separated in a central axis (X) direction of the rod body 22, and a straight rod portion 30 (see FIG. 4) located between the screw-in portion 26 and the head portion 28. The screw-in portion 26 is formed into a tapered shape and has a tip 31, and the screw-in portion 26 has a first length (L1) in the axis direction. The upper surface of the head 28 has a bearing hole 32 for inserting a screwdriver tool (not shown). The straight rod portion 30 has a circular transverse section and includes a lower section 34 adjacent to the screw-in portion 26 and an upper section 36 adjacent to the head 28. The first length (L1) is defined by the axial distance between the tip 31 and the bottom end 38 of the straight rod portion 30.

The first thread 24 is helically provided on the rod body 22 and extends from the tip 31 of the screw-in portion 26 to the lower section 34 of the straight rod section 30, but does not extend to the upper section 36 of the straight rod section 30. In a feasible embodiment, the first thread 24 may extend to the upper section 36 of the straight rod portion 30. The first thread 24 includes a plurality of threads 40, and a pitch (P) is defined between two adjacent threads 40.

The screw 20 further includes a second thread 42 and a plurality of ribs 44. The second thread 42 is helically provided on the screw-in portion 26 and is spaced apart from the first thread 24. The second thread 42 includes a lower end 46 adjacent to but separated from the tip 31 and a straight rod portion 30 has a bottom end 38 but an upper end 48 separated from the bottom end 38. The second thread 42 has a second length (L2) in the axis direction. The second length (L2) is defined by the axial distance between the lower end 46 and the upper end 48 of the second thread 42. The second length (L2) is preferably 30-75% of the first length (L1). The plurality of convex ribs 44 are provided on the lower section 34 of the straight rod portion 30 along the circumferential direction of the straight rod portion 30 and extend along the axis, and each of the convex ribs 44 is located between the adjacent two screw teeth 40 The height of each straight rib 44 protruding from the straight rod portion 30 is smaller than the tooth height of the screw thread 40. In this embodiment, the bottom 50 of each rib 44 is adjacent to the bottom end 38 of the straight rod portion 30 but separated from the bottom end 38 by a distance less than the pitch (P) (see FIG. 3). Furthermore, the ribs 44 has a third length (L3) in the direction of the axis, the third length (L3) is preferably less than two pitches (P), that is, the extension length of the rib 44 in the axis preferably does not exceed Three threads 40 on the lower section 34.

In the implementation of the screw 20 of the present invention, the tip 31 of the screwing portion 26 is used as a positioning point to insert into an object such as a wooden board, and then, the screw 20 is driven to rotate by using the bearing hole 32 of the head 28 inserted by a tool (not shown) , So that the first thread 24 on the screw-in portion 26 is screwed into the object to form a drill hole. During the screwing of the screw-in portion 26 into the object, the second thread 42 on the screw-in portion 26 will assist the cutting of the first thread 24 to enlarge the drilled hole, so as to reduce the resistance of the screw-in portion 26 in the locked object to increase the rotation Speed; then, when the straight rod portion 30 is to be screwed into the object, the plurality of ribs 44 will assist the first thread 24 to cut the object and perform the work of chip accumulation and chip removal, so as to reduce the locking of the straight rod portion 30 Resistance in the object to increase the screwing speed; further, as shown in FIG. 5, the radial distance (A) of the top of the rib 44 and the central axis (X) is greater than or equal to the crest of the second thread 42 The radial distance (B) from the central axis (X), according to this, can prevent the wood from breaking during drilling and improve the bite force between the straight rod portion 30 and the object. Therefore, the screw 20 of the present invention is labor-saving and fast in operation, and has the effect of improving the bite force. Therefore, it is particularly suitable for hard (high wood density) plate connection.

The screw 20 of the present invention has the design of the second thread 42 and the rib 44 in addition to the above-mentioned implementation effects. Since the second thread 42 and the first thread 24 of the present invention are manufactured in the screw 20 It can be formed together during the process, so the manufacturing cost can be reduced, and the screw 20 of the present invention does not need to provide grooves or notches in the rod body 22, so the structural strength of the screw 20 can be improved.

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

20‧‧‧screw

22‧‧‧Pole

24‧‧‧First thread

26‧‧‧ Screw-in Department

28‧‧‧Head

30‧‧‧Straight rod part

31‧‧‧tip

34‧‧‧Lower

36‧‧‧Upper

38‧‧‧Bottom

40‧‧‧screw

42‧‧‧Second thread

44‧‧‧Convex rib

46‧‧‧lower

48‧‧‧Upper

50‧‧‧Bottom

Claims (6)

A screw includes: a rod body including a screw-in portion and a head portion separated in an axis direction of the rod body and a straight rod portion between the screw-in portion and the head portion, the screw-in portion has a tip , The straight rod portion includes a lower section adjacent to the screw-in portion and an upper section adjacent to the head; a first thread, which is spirally provided on the rod body and extends from the tip of the screw-in portion to the straight rod portion , The first thread includes a plurality of threads, and a pitch is defined between two adjacent threads; a second thread is spirally provided on the screw-in portion and is spaced apart from the first thread, the second thread includes A lower end adjacent to the tip but separated from the tip and an upper end adjacent to the bottom end of the straight rod portion but separated from the bottom end; and a plurality of ribs are provided on the straight rod portion separately along the circumferential direction of the straight rod portion In the lower section of the straight rod portion, each convex rib is located between two adjacent teeth, and the bottom of each convex rib is adjacent to but separated from the bottom end of the straight rod portion. The screw according to item 1 of the patent application scope, wherein the screw-in portion has a first length in the axial direction, and the second thread has a second length in the axial direction, the second length being of the first length 30-75%. According to the screw described in item 1 of the patent application scope, wherein the height of each convex rib protruding from the straight rod portion is smaller than the tooth height of the screw tooth, the plurality of convex ribs extend along the axis and the bottom of each convex rib and the straight The distance at which the bottom end of the rod part is separated at the axis is smaller than the pitch. The screw as described in item 3 of the patent application, wherein the convex rib has a third length in the axial direction, and the third length is less than two pitches. The screw according to item 2 or 3 of the patent application scope, wherein the first thread extends from the tip of the screw-in portion to the lower section of the straight rod portion, but does not extend to the upper section of the straight rod portion. The screw according to item 1 of the patent application scope, wherein the radial distance between the top of the rib and the central axis is greater than or equal to the radial distance between the crest of the second thread and the central axis.

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