AU2020200925B1 - Screw Head - Google Patents

Abstract

A screw head (3) includes a top surface (31), a bottom portion (32), and a peripheral surface (33) formed between the top surface (31) and the bottom portion (32) and having grooves (34) inclinedly 5 formed thereon. Each groove (34) includes opposite first and second side edges (Bi, B2) extending from the bottom portion (32) towards the top surface (31) and a connecting edge (B3) extending from the first side edge (Bi) to the second side edge (B2). The side edges (Bi, B2) extend respectively to define a first reference line (Li) 0 and a second reference line (L2) respectively. A first included angle (Al) formed between the first reference line (Li) and the top surface (31) is different from a second included angle (A2) formed between the second reference line (L2) and the top surface (31). An area (34a) of each groove (34) increases gradually from the bottom portion (32) 5 toward the top surface (31) and is curved in shape whereby a rib (35) is defined between every two adjacent grooves (34) to help scrape burrs and attain a firm fastening effect. 13

Description

P/00/011 Regulation 3.2 AUSTRALIA

Patents Act 1990

COMPLETE SPECIFICATION FORASTANDARDPATENT ORIGINAL TO BE COMPLETED BY APPLICANT

Invention Title: Screw Head

Name of Applicant: Taiwan Shan Yin International Co., Ltd.

Address for Service: A.P.T. Patent and Trade Mark Attorneys PO Box 833, Blackwood, SA 5051

The following statement is a full description of this invention, including the best method of performing it known to me/us:

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SCREW HEAD BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a screw structure and relates

particularly to a screw head of the screw structure.

2. Description of the Related Art

Referring to Fig. 1, a conventional screw 1 includes a head 11,

a shank 12 longitudinally extending from the head 11 and forming a

drilling portion 13 opposite to the head 11, and a threaded portion

14 spirally disposed around the shank 12. The head 11has a top surface

111, an underside 112 extends from the top surface 111 to the shank

12, and a plurality of protrusions 15 projecting from the underside

112. When the head 11 meets a workpiece 2, the protrusions 15 serve

to scrape burrs 6 forced out of the surface of the workpiece 2 in

order to help the head 11 fit with the workpiece 2. Generally, the

protrusions 15, usually shaped by pressing with a tool such as dies,

are sharper or stick out by a lengthbeyond the standard for increasing

the effect of scraping burrs 6. However, the sharper the protrusion

15 gets, the more damage the tool suffers. It is also possible that

!0 the tool is more easily damaged while shaping the protrusions 15 with

the undue sticking length. Accordingly, the amount of consuming the

tool increases, which leads to higher manufacturing costs. Further,

the protrusions 15 are mainly designed to scrape the burrs 6 but are

unfavorable to the fastening effect because there is no space for accommodating chips cut by the threaded portion 14, and the burrs are easily forced out of a drill bore generated by screwing the screw

1 into the workpiece 2 and thus are exposed to the outside. In other

words, the head 11 cannot fit snugly with the workpiece 2, so a poor

fastening effect is caused.

SUMMARY OF THE INVENTION

An object of this invention is to provide a screw head capable

offitting snuglywith the workpiece to attain a firmfasteningeffect.

Another object of this invention is to provide a screw head which

helps decrease the damage to a forming tool at the time of forming

the screw head to thereby reduce manufacturing costs efficiently.

The screw head of this invention includes a top surface defining

a central axis, a bottom portion, and a peripheral surface formed

between the top surface and the bottom portion. On the peripheral

surface are formed a plurality of grooves inclined to the central

axis.Arib appears betweenevery two adjacent grooves when the grooves

are formed in a curved shape. Each of the grooves includes a first

side edge, a second side edge opposite the first side edge, and a

connecting edge extending from the first side edge to the second side

!0 edge. The first side edge and the second side edge extend from the

bottom portion towards the top surface respectively to define a first

reference line and a second reference line respectively. A first

included angle formed between the first reference line and the top

surface is different from a second included angle formed between the second reference line and the top surface so that the groove is asymmetric. Each groove has an area increasing gradually from the bottom portion toward the top surface, and the area of each groove is curvedin shape whereby each rib definedbetween every two adjacent grooves serves as a portion extending from the first side edge of one groove to the second side edge of another adjacent groove.

Accordingly, the cooperation between the curved grooves and the ribs

not only scrape and press burrs which are generated on a surface of

a workpiece downwards but also provides a larger space for

accommodating cut chips and burrs to thereby obtain a firm fastening

effect. The ribs are not sharp because of the gradually-increasing

and asymmetric contour of the grooves, and therefore a tool of forming

the screw head suffers less damage and manufacturing costs are

decreased.

Preferably, in one preferred embodiment, the first side edge can

further include a first straight line and a first curved line connected

to the first straight line, and the second side edge can further

include a second straight line and a second curved line connected

to the second straight line. It is also preferable that both of the

!0 first straight line and the second straightline extend from the bottom

portion, the first curved line extends from the first straight line

to the connecting edge, and the second curved line extends from the

second straight line to the connecting edge.

Preferably, in the preferred embodiments, each of the grooves can

extend leftwards or rightwards from the bottom portion.

Preferably, in another preferred embodiment, an extension surface

can be formed between the top surface and the peripheral surface,

and the groove extends to a place where the extension surface and

the peripheral surface meet.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view showing a conventional screw with a common

screw head;

Fig. 2 is a schematic view showing a first preferred embodiment of

this invention in a front elevational view;

Fig. 2A is an enlarged view showing the encircled portion X of Fig.

2;

Fig. 3 is a cross-sectional view taken along the A-A line of Fig.

2 where the grooves extend in a left direction;

Fig. 4 is a cross-sectional view showing one variation of Fig. 3 where

the grooves extend in a right direction;

Fig. 5 is a schematic view showing an operation of the first preferred

embodiment of this invention;

!0 Fig. 6 is a schematic view showing a second preferred embodiment of

this invention in a front elevational view; and

Fig. 6A is an enlarged view showing the encircled portion Y of Fig.

6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Fig. 2 and Fig. 2A, a first preferred embodiment of

a screw head 3 includes a top surface 31 which defines a central axis

3a, a bottom portion 32, a peripheral surface 33 formed between the

top surface 31 and the bottom portion 32, a plurality of grooves 34

formed on the peripheral surface 33 and extending from the bottom

portion 32 towards the top surface 31, and a plurality of ribs 35

each formed between every two adjacent grooves 34. The peripheral

surface 33 can be formed in a conical contour. In the preferred

embodiment, the screw head 3, as shown, is adapted to combine with

a shank 41 around which a threaded portion 42 is spirally disposed,

thereby constructing a full screw fastener 4. It is preferable that

the shank 41 extends downwards from the bottom portion 32, as shown.

An area 34a of each groove 34 defined on the peripheral surface

33is curvedin shape. Specifically, the groove 34is recessedly formed

to render two side parts of the groove 34 higher than a middle part

thereof, and each side part of the groove 34 is defined as the rib

35. Each of the grooves 34 is inclined to the central axis 3a, and

concurrently the area 34a of each groove 34 increases gradually from

the bottom portion 32 toward the top surface 31. Accordingly, each

!0 rib 35 can also increase gradually from the bottom portion 32 toward

the top surface 31, as for example shown in Fig. 2A. It is possible

that the extension of the groove 34 may reach a periphery of the top

surface 31 or may terminate before the periphery of the top surface

31. Regarding the inclination of the grooves 34, the grooves 34 can extend leftwards from the bottom portion 32 as shown in Fig. 3 when viewed from the bottom portion 32 to present a counterclockwise arrangement. Alternatively, the grooves 34 can extend rightwards from the bottom portion 32 as shown in Fig. 4 when viewed from the bottom portion 32 to present a clockwise arrangement.

Each of the grooves 34 includes a first side edge B1, a second

side edge B2 opposite the first side edge B1, and a connecting edge

B3 extending from the first side edge B1 to the second side edge B2.

In other words, each connecting edge B3 extends between every two

adjacent ribs 35, and the first side edge B1 of one groove 34 and

the second side edge B2 of another adjacent groove 34 are also deemed

as two side edges of each rib 35. Therefore, the rib 35 is a portion

extending from the first side edge B1 of one groove 34 to the second

side edge B2 of another adjacent groove 34. Furthermore, the first

side edge Bl extends from the bottom portion 32 towards the top surface

31. As shown in Fig. 2A, the first side edge B1 starts from the bottom

portion 32 and extends in the direction of the top surface 31, thereby

defining a first reference line L1. The second side edge B2 extends

from the bottom portion 32 towards the top surface 31. As shown in

!0 Fig. 2A, the second side edge B2 starts from the bottom portion 32

and extends in the direction of the top surface 31, thereby defining

a second reference line L2. Under the extension of the groove 34,

the connecting edge B3 may reach the periphery of the top surface

31 or may terminate before the periphery of the top surface 31.

Furthermore, the top surface 31 further defines a horizontal line

LO perpendicular to the central axis 3a. A first included angle Al

is formed between the first reference line L1 and the horizontal line

LO of the top surface 31. A second included angle A2 is formed between

the second reference line L2 and the horizontal line LO of the top

surface 31. The first included angle Al and the second included angle

A2 are different, so the groove 34 is shaped like an asymmetric sector.

In the preferred embodiment, it is preferable that the first side

edge B1 includes a first straight line B11 and a first curved line

B12 connected to the first straight line B11. Preferably, one end

of the first straight line B11 is connected to the bottom portion

32, and the first curved line B12 extends from the other end of the

first straight line B11 to the connecting edge B3. When the first

straight line B11 extends from the bottom portion 32, the

aforementioned first reference line L1 is defined. Likewise, it is

preferable that the second side edge B2 includes a second straight

line B21 and a second curved line B22 connected to the second straight

line B21. Preferably, one end of the second straight line B21 is

connected to the bottom portion 32, and the second curved line B22

!0 extends from the other end of the second straight line B21 to the

connecting edge B3. When the second straight line B21 extends from

the bottom portion 32, the aforementioned second reference line L2

is defined.

Referring to Figs. 2 and 3, during the manufacturing processes,

the processes include forming the screw head 3 at one end of the shank

41 and also forming the grooves 34 on the peripheral surface 33 in

a curvilinear way to obtain a curved contour whereby two side parts

of the groove 34 is higher than the middle part thereof so that the

two side parts serve as two ribs 35, as aforementioned. The area 34a

of each groove 34 also increases gradually from a point where the

bottom portion 32 and the shank 41 intersect toward the periphery

of the top surface 31. Thus, the ribs 35 are not so sharp because

of a combination of the asymmetric curved shape and the

gradually-increasing arrangement of the grooves 34, which allows a

tool such as dies (not shown) to suffer less damage at the time of

forming the grooves 34 and ribs 35 and also decreases manufacturing

costs.

An operation of this invention is described with the aid of Figs.

2 and 5 in which the screw fastener 4 with the screw head 3 is adapted

to be screwed into a workpiece 5. When the threaded portion 42 starts

a screwing operation, a drill bore 51 is formed and the shank 41 is

gradually drilledinto the workpiece 5. During the screwingoperation,

!0 chips andburrs cutby the threadedportion 42 are graduallygenerated.

The burrs are also accumulated on the surface of the drill bore 51.

When the peripheral surface 33 touches the burrs, each rib 35 with

the two side edges B1, B2 executes a scraping operation. Specifically,

narrow portions of each gradually-increasing recessed groove 34 and each rib 35 can include the first straight line B11 and the second straight line B21 which are located higher than the curved portion of the groove 34, so the burrs are efficiently scraped by the ribs

35.

When the screw head 3 keeps screwing into the drill bore 51, wide

portions of each groove 34 and each rib 35, including the first curved

line B12 and the second curved line B22, provide more space for

accommodating the cut chips and the scraped burrs. Meanwhile, the

burrs are pressed back into the drill bore 51 by the inclination of

the grooves 34, with the result that the burrs are fully covered by

the screw head 3 and are densely accommodated in the grooves 34 and

the drill bore 51. Therefore, the screw head 3 fits snugly with the

surface of the workpiece 5, and the screw fastener 4 is firmly fastened

to the workpiece 5, thereby attaining a firm fastening effect. It

is also possible that the top surface 31 is flush with the surface

of the workpiece 5 after the screwing operation is done.

Referring to Figs. 6 and 6A, a second preferred embodiment of a

screw head 3 has the same elements, operations, and effects as those

of the first preferred embodiment. The second preferred embodiment

!0 is characterised in that an extension surface 37 is formed between

the top surface 31 and the peripheral surface 33, and the grooves

34 extend to a place where the extension surface 37 and the peripheral

surface 33 meet to thereby present another variation of the screw

head 3. It is noted that the extension surface 37 can be perpendicular to or be inclined to the top surface 31.

To sum up, this invention mainly includes a plurality of grooves

inclinedly formed on a peripheral surface of a screw head. Each groove

has opposite first and second side edges and a connecting edge

extending from the first side edge to the second side edge. Both side

edges extend from a bottom portion of the screw head toward a top

surface thereof to define a first reference line and a second reference

line respectively. A first included angle formed between the first

reference line and the top surface is different from a second included

angle formed between the second reference line and the top surface.

Each groove has an area increasing gradually from the bottom portion

toward the top surface and is curved in shape to thereby present a

rib between two adjacent grooves. By a combination of the curved

grooves and the ribs, burrs caused by a screwing operation around

a drill bore are efficiently scraped, and the burrs and cut chips

are then accommodated within the grooves. The burrs are also pressed

back into the drill bore to thereby allow the screw head to fit snugly

with a workpiece and attain a firm fastening effect. Further, the

tool of forming the claimed screw head is not easily damaged when

!0 the ribs are not very sharp because of the special contour of the

grooves, thereby reducing manufacturing costs.

While the embodiments are shown and described above, it is

understood that further variations and modifications may be made

without departing from the scope of this invention.

Claims (4)

WHAT IS CLAIMED IS

1. A screw head comprising a top surface defining a central axis, a bottom portion, and a peripheral surface formed between said top surface and said bottom portion; wherein a plurality of grooves are recessedly formed on said peripheral surface and inclined to said central axis, each of said plurality of grooves including a first side edge, a second side edge opposite said first side edge, and a connecting edge extending from said first side edge to said second side edge, said first side edge and said second side edge extending from said bottom portion towards said top surface respectively to define a first reference line and a second reference line respectively, a first included angle being formed between said first reference line and said top surface, a second included angle being formed between said second reference line and said top surface, said first included angle being different from said second included angle so that each of said plurality of grooves is formed in an asymmetric arrangement, each of said plurality of grooves having an area increasing gradually from said bottom portion toward said top surface, said area of each of said plurality of grooves being curved in shape, with said connecting edge thereof formed in a curved profile, and a rib thereby being defined between every two adjacent grooves and serving as a portion extending from said first side edge of one of said adjacent grooves to said second side edge of another one of said adjacent grooves; wherein said first side edge includes a first straight line and a first curved line connected to said first straight line, said second side edge including a second straight line and a second curved line connected to said second straight line, with said first straight line connected to said bottom portion, said first curved line extending from said first straight line to said connecting edge, said second straight line connected to said bottom portion, and said second curved line extending from said second straight line to said connecting edge.

2. The screw head according to claim 1, wherein an extension surface is formed between said top surface and said peripheral surface, said plurality of grooves extending to a place where said extension surface and said peripheral surface meet.

3. The screw head according to claim 1 or 2, wherein each of said plurality of grooves extends leftwards from said bottom portion.

4. The screw head according to claim 1 or 2, wherein each of said plurality of grooves extends rightwards from said bottom portion.