DE7430267U - FASTENING ELEMENT - Google Patents

Description

pat ε NTANWA ₁ LT ^ -OZIkCK-E Nw £: LAU F ER

DR. HUGO WILCKEN DIPL.ING. THOMAS wiUCJiEN. · DIp] l.-c '| -J EM. DR. WOLFG ANG LAUFER

LOBECK LOBECK MÖNCHEN

YAMAMOTO BYORA CO., LTD.
2-2, 4-chome, Ai "akawa, Arakawa-ku
Tokyo (Japan)

Fastener

The invention relates to a fastener such as a Screw, bolt or nut.

There are known screws that have a slotted head or a Phillips head own. This type of screws have the disadvantage that the efficiency of the transmission of the torque is limited and that the inner wall of the slot or recess can easily be worn or damaged.

With the conventional screws, nuts or bolts, which have a hexagonal screw head or body, the so-called

ο "Driving angle" is large and is 60. The so-called "drive angle"wi'Vj is defined by a radial line that runs through a force-acting point with a line tangential to the contour

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7430267 O5.oa76

Fastening device at the point where the force is applied. For this reason, the fastening device (fastener driver) can slide to de ^r outer wall of the screw head when the screwed; is tightened or loosened, so that the loss of torque is increased and the edge parts are damaged or worn. Based on these facts, the edge parts are rounded off. In addition, the raw material of the screw head has a circular cross-section and must be converted into a hexagonal cross-section during machining, which requires complicated manufacturing processes and increased manufacturing costs.

In order to avoid the disadvantages indicated above, a screw head is used has been proposed, which has a plurality of notches, incisions, grooves and noses or vo * 'cracks on its periphery, the lugs are each located between two adjacent notches. However, the "drive angle" is also the same for this type of screw head still relatively large and the disadvantages indicated above are not completely eliminated. Furthermore, the dimensions of the Notches and lugs are not taken into account with regard to the mechanical strength of the screw head and the fastening device used. For these reasons, the lugs of such screw heads can also be easily damaged or worn.

The invention was based on the object of a fastening element develop in which an extremely high efficiency of the transmission of the rotational force is caused, which is designed so that damage and rapid wear caused, the dimensions of which are chosen with respect to its mechanical strength so that damage prevented even if a full

Transmission of the torque is achieved, and that easily with de '"fastening device can be brought together or detached from this and engages in an advantageous manner in the fastening device.

The task at hand could surprisingly be solved by that turn several notches created on the periphery of the cylindrical upper part of the screw head, each one partial have a circular cross-section and this partial circle is so defined

is ned that it sets the "drive angle" to zero. To do this too reach, we <j the center of the partial circle of the notch arranged in a radial line that extends from the center of the cross-sectional circle of the upper part of the screw head and within a region of the radial line between the last mentioned Center and a first intersection point is defined at which two tangential lines intersect. These tangential lines touch the Cross-sectional circle of the upper screw head part at the second intersection points, at which the partial circle of the notches is the cross-sectional circle of the upper part of the screw head.

With fastening elements of this type, no force component is generated that would prevent the fastening device from sliding off the fastening element caused. Therefore, the rotating force of the fastener is fully transmitted to the fastener and it occurs hardly any damage or wear to the fastening element.

In those cases where the center of the partial circle is radial is arranged outside the first intersection, as with the screws according to the prior art, shows the "drive

angle "values greater than O C an in relation to the drive direction of the Fastening device and this leads to the disadvantages described above.

The center of the partial circle of the notch is preferably arranged between the first point of intersection and an arc or chord of a circle which connects the second points of intersection. When the center of the circle is within the partitiellen sheet or chord with respect to the center of the cross-sectional circle of the upper screw head 'part, it may very easily to a cancel the side corners or

Side edges of the nose come up and also it is difficult to fasten the fastening device to be attached to the fastener.

Preferably in the fastening elements according to the invention four to eight notches chosen, and in most cases six notches. If the number of notches is less than four, difficulties arise when attaching the fastening device to the fastening element. If the number of notches is more than eight, then those between the Notches located lugs too narrow and it can therefore easily wear of the noses and, moreover, it is easy for errors to occur in the dimensioning and arrangement of the notches during manufacture.

Preferably the notches are equally spaced on the periphery of the upper part of the screw head and the diameter of the partial circle of the notch is defined by the following equation:

I "I ■ D _o <d _o <- .J ₅ -D ₀ (1)

In the above formula, η gives the number of notches, d the diameter

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of the partial circle of the notch and D is the diameter of the cross-sectional circle of the upper part of the screw head (cross sectional circle of the male portion).

If the diameter of the partial circle of the notch is determined in this way, even with complete transfer of the Torque does not damage the fastening device or the fastening element caused. The reasons for this are described below.

Usually the material that makes up a screw becomes a bolt or a nut is produced, standardized in such a way that there is a

i 2

strength of o- is 45 to 180 kg / mm, while the material, fci

from which the fastening device consists, is standardized so that

it has a tensile strength of o- from 120 to 180 kg / mm. Since the

Shear or shear strength of these types of materials and in particular of Steel can be viewed as proportional to the tensile strength of these materials, the ratio of the shear or shear strength of the Fastening element to that of the fastening device in the area from 1.5: 1 to 1: 4. Since the shear or shear strength of the fastening element does not normally exceed that of the fastening device, this ratio is in the range from 1: 1 to 1: 4. It follows that the shear or shear resistances of the needle of the fastening element and the projection of the fastening device are compensated when the ratio width of the force receiving part (force-transmitted portion) (i.e. the nose of the fastener between two adjacent Notches of the fastening element is defined) to the force-transmitting portion (i.e. the projection of the Fastening device that attaches to the notch of the fastener

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in the range of 1: 1 to 4: 1.

Since the width of the projection of the fastening device is substantially the width of the notch of the fastening element is equal and this width of the notch is equal to the diameter d of the partial circle of the Approaching the notch, the diameter d is defined by the following equation:

In the above equation, I is the width of the nose of the fastener.

On the other side, the width of the nose is essentially the same as that Arc length of the outer peripheral edge of the noses and can therefore can be expressed as follows:

= ή ' ^D o- ^d o

Accordingly, the equation (1) is derived from the equations (2) and (3). For example, if the number η of the notches is set to six, the ratio between the diameter of the notch of the partial circle and the diameter of the cross-sectional circle of the upper part of the screw head is expressed by the following equation.

0.1 D _ d _ 0.25 D

Most often fasteners are used, their tensile strength in a ratio of 1: 2 to 1: 3 to the tensile strength of the fastening

direction lies. For reasons of practical usability, and the economy becomes the diameter of the notch of the partial. Circle preferably defined as follows:

1
η 0 = 0 = 3 'τγ °

The upper part of the screw head preferably runs at an angle

ο ο

from 1 to 10 together with respect to the central axis of the fastener and is more inclined than the corresponding mating one concave part of the [fastening device. The cross section of the lower end of the concave part of the fastening before direction corresponds to a Cross-section of the upper part of the screw head slightly above the lower end of the same. This type of structure of the fastening element enables an extremely easy removal of the fastening element from the Form after manufacture and also extremely easy to attach or removing the fastening device on or from the fastening element. Will the fastener on the fastener attached, it fits snugly and firmly to the fastener at a point slightly above the lower end of the Fastening element lies. This construction prevents that the fastening element falls off the fastening device due to its weight, which creates particular advantages are tight with regard to the attachment of the fastening element Assembly areas that cannot be reached by hand.

The fastening elements according to the invention are explained in de ¹ "following description with reference to the accompanying drawings.

7430267 08/05/76

13 \

Figure 1 is a plan view of a screw or fastener according to the invention.

FIG. 2 is a side view of the screw shown in FIG. 1.

Fig. 3 is a cross section through a screw according to FIG. 1, on which one Fastening device for fastening and loosening this screw (fastener driver) attacks.

FIG. 4 is a cross section taken along line 4-4 of FIG. 3.

Figures 5A and 5B show the relationship of the "driving angle" to the position of the notch of the screw according to FIG. 1.

Fig. 6 is a perspective view of a nut and another Embodiment of the fastening element according to the invention.

FIG. 7 is a cross section through the nut shown in FIG. 6.

8 is a perspective view of another embodiment of a Screw or a fastening element according to the invention.

1 and 2 show a screw 11 according to the invention. the Screw 11 consists of an essentially cylindrical head 12, which at its cross-section forms a larger circle 18 (see Fig. 4), a flange-like washer 13, which extends radially from the bottom part of the screw - head extends, and from a threaded shaft extending axially from the washer of the screw head. Of the

7430Z67 85.oa76

Screw head 12 has on its outer peripheral wall six substantially senicylindrical notches 15 which are arranged at equal distances from one another. Between the adjacent notches' there are protrusions or lugs) 6, the outer walls 17 of which have a curved cross-section. These notches have over the entire length, a constant width and extend from the upper end of the screw head to the lower end along the central axis of the screw head 12. The cross section of each notch provides a semi-circle 19 represents the from the large Kr _e is 18 inwardly is concave. The center is denoted by the reference number 0.

■ Jen Fig. 3 to 5B it can be seen that the screw head 12 on a engaging recess or groove 22 is adapted, which is formed in a mounting part 21 of the fastening device 20 (driver). The recess 22 has a cross section which has completely the same cross section as the screw head 12. The mounting part 21 has at its upper part a hole 23 which has a rectangular cross-section. A handle (not shown here) can be inserted into the hole 23 so that the fastening device 20 can be rotated.

There are engaging protrusions in the inner wall of the recess 22 24, which have a substantially semicircular cross-section which is complementary to the notches 15 and which in the engage the corresponding notches. The effective exaggeration of the drive torque the engagement of the tabs 24 of the fastener with the lugs 16 of the screw head requires consideration "Drive Angle". This "drive angle" is defined by a radial one Line that goes through a point (this is a force-acting point), on which the fastening device presses the screw head when the screw is tightened or loosened) with a tangential line

- 10 -

7430267 flioa7e

the contour of the recess of the fastening device at this force-acting point. If the "drive angle" is positive with respect to <\ c ^r set by the fixture direction, a force component is generated which causes not hkraft sufficiently Dr _e is transmitted to the screw head, and further results in that the fastening device external of the Wall of the screw head slides off. Because of this slippage, the possibility of the side corners of the lugs of the screw head being worn or damaged is increased

ο be. On the other hand, if the "drive angle" is 0 with respect to the direction set by the fastening device, the above-mentioned sliding cannot take place and thereby an extremely efficient transmission of the rotational force is effected and a good engagement of the fastening device with the screw head is obtained. Due to this fact, the aim of the present invention was to determine the shape of the notches 15 of the screw head so that ^{: |} Drive angle "at 0 is under consideration
called direction.

0, taking into account the

FIGS. 5A and 5B show in schematic ^r, the ratio between different positions of the center of the half circle of the notch 15 and the drive angle. Since the configuration of the cross-section of the screw head can be regarded as essentially the same as the configuration of the recesses 22 of the fastening device, the outer wall of the screw head and the inner wall of the recesses are shown with the same curved lines in FIGS. 5A and 5B .

From Fig. 5A it can be seen that the central point 0 of the semicircle 19 of the engaging projections 24 and accordingly the notches

- 11 -

at the intersection of the "" tangential lines 25 and 25a which are tangential to the larger K ^ ais 18 of the blade head 12 at the intersection points P and P when the semicircle 19 intersects the larger circle 18. In this f-'a \\ the intersection point P is regarded as the force-applied point F when the screw head is driven or rotated into the seal indicated by the arrow A, and the tangential line meet the projection 24 of the fastening device at point B with the radial line OP. In this case

O
carries the "drive angle" O and enables a complete transmission of the rotational force from the projection 24 to the nose 16.

5B it can be seen that the central point O of the partial circle 19 is arranged on the arc or chord 26 and the points of intersection P and P of the larger circle 18 and the semicircle 19 connects. In this case, the force applying point F is located somewhat within the circle 18 and the tangential line to the semicircle 19 at point F coincides with the radial line OP. Therefore, the "drive angle" is as in the case of the above example.

If the central point O of the partial circle 19 is positioned as described above

o is arranged, then the "drive angle" is at O with respect to that of the Fastener caused direction. Because of this, it never will Efficiency of the transmission of the rotational force is extremely increased and a Prevents the fastening device from slipping.

When the central point O of the semicircle 19 is within the arc or circular chord 26 is located with respect to the central point O of the larger circle 18, then the "drive angle" is also at O, However, the lateral corners of the nose 16 are very close to the

- 12 -

7430267 05.0178

Force-acting point, so that there is damage to the nose can.

In the present invention, in addition to the precise adjustment of the center of the notch semicircle also the material quality of the fastening element and the fastening device is observed, so that damage to both the fastening element and the fastening device can be prevented even if the torque is completely removed from the Fastening device is transferred to the fastener.

When the shear or shear forces of the materials used to make the screws and fasteners are taken into account, the ratio of the width of the projection 24 of the fastener to the width of the nose 16 of the screw must be in the range of 1: 1 to 1: 4 and are preferably in the range from 1: 2 to 1: 3 to the Schubbzw. Equalize the shear resistance of the bolts and fasteners near the points the force is applying and to which force is being applied. The width L of the engaging vor ρ tion 24 shown in Fig. 4 is substantially equal to the width L of the notch 15 and the notch width L approaches the diameter d of the semicircle 19. Therefore, the ratio between the width I of the nose 16 and the diameter d of the semicircle is defined as follows

or preferably

3 = 0 ^ 2

- 13 -

7430267 05th part 7C

On the other hand, the width I is substantially equal to that Arc length of the circle 18, which is defined between two adjacent semicircles. thats why

ι "JT ^" 0 0

when the latter equation is substituted into the previous equation will, then is

J. T. D / d <1 T "π
5 η 0 ^ ο = 2 'η 0

or preferably

4 Ti 0 ^ ^d 0 = 3 "ri ° 0

since the number η of notches 15 in this embodiment is six is, the diameter d of the semicircle 19 must have the following ratio with the diameter D of the circle 18 have:

0.1 D £ d <. 0.25 D

or preferably

0.12 D <d <0.17 D

When the diameters of the semicircle 19 and the larger circle 18 are set as above, the corresponding shear or shear resistances of the engaging projection 24 of the fastener and the nose 16 of the fastening element or the screw

- 14 -

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mutually balanced. Even if a full transfer of the Rotational force is exerted on the screw by the fastening device, there is no damage.

On the other hand, the screws are damaged if ä y -ς. Έ. D. if

conversely d <-. IT. D_ then it can damage the Be-0 5 η 0

Fastening devices come.

From Fig. 3 it can be seen that the notch 15 and the nose 16 are inclined with the angles and ß with respect to the central axis 0-0 of the screw head. The angles crt and ß compensate each other and are determined within the range 1 << Λ = β i · 10.

The engaging projection 24 of the fastening device extends on the other side and the engaging notch 27 formed between two adjacent engaging protrusions with angles

γ and © together with respect to the central axis 0-0. The relationship between the angles & \ and ß is as follows:

K = β > r = θ

A maximum distance C between the bottom of the notch 15 and the Central axis 0-0 of the screw head leads to the following relationship with a maximum distance C between the apex of the encroaching Projection 24 and the central axis 0-0 of the fastening device:

maximum outer diameter ^ D of the screw head results in the following relationship with the maximum inner diameter D of the itself

IO

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matching concave part 22 de »" Fastening device:

Furthermore, the disk 13 converges at an angle S. if under these conditions the height of the screw head, namely the distance between the upper end of the washer 13 and the lower one The end of the screw head is denoted by H and the distance between the upper end of the screw head and the engaging point P of the screw head with the fastening device Q is given, then the following relationship will always arise:

Q i H

If the fastening device is attached or adapted to the screw head, then the fastener is normally prevented from abutting the upper surface of the disc and yet the fastening device adapts itself to the screw head in a reliable manner and that at a point which is slightly above of the upper end of the disc. This prevents the fastening device from being easily detached from the screw head. One This type of screw is formed by pressing or cold forging. The easy removal of the screw from the metal mold is achieved due to the converging configuration of the molded object, i.e. the screw head.

Figures 6 and 7 show a nut according to the present invention. The first nut consists of a body 28, which has a screwdriver opening 29 in the central part. Several notches 30, lugs 31 and the disc ·. · '.; ■■ _ ir, d <-ra,, f;, .. r _f _> n periphery of the body have the same

- 16 -

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Refinements as shown in FIGS. 1 to 5C.

Fig. 8 shows a further embodiment of a nut according to de * " Invention. This mother has the same design as in the 6 and 7 shown, but it has no disc.

■ claims: - 17 -

Claims (9)

»- Κ η s ρ 1 . Fastening element with a plurality of notches on the periphery of the head portion extending along the central axis of the head portion and having a plurality of lugs extending between adjacent ones Notches are located, characterized in that the head part (12, 28) forms a first circle (18) on its cross section, each of the notches (15, 30) of the head part one at its cross section forms a partial circle (19) which is curved within the first circle, and the center (0) of the partial circle on a corresponding radial Line extending from the center (O) of the first circle and within a range this radial line which is defined between the latter center and a first point of intersection at which two tangential lines (25, 25a) intersect, the tangential lines touching the first circle at second intersection points (P. P) where the first circle intersects the partisan circle, wherein the notches and tabs are connected to the corresponding engaging protrusions and notches of the fastening device when the fastening element is attached to a recess of a fastening device is attached, which has a similar cross-section as the fastener. 2. Fastening element according to claim 1, characterized in that the center (O) of the partial circle between a first intersection and a chord (26) connecting the second intersection (P and P). - 18 - 7430267 95.08.78 3. Fastening element according to claims 1 and 2, daaur-ch characterized in that the notches (15, 30) of the head part (12, 28) arranged in a circle around the head part at equal intervals are, and the diameter of the notch of the partial circle by the equation 5 η ^u = O = 2 'η "" O ¹ ■ ^Κ ' ^D ₀ - ^d ~ < ^ - υ -D, is defined where D is the diameter · "of the first circle represents, d is the diameter of the patitial circle, and η the Number of notches in the head part. 4. Fastening element according to claims 1 to 3, characterized in that the notch (15,30) and the nose (15, 31) of the head part (12, 28) to the central axis (0-0) of the head part are inclined with angles that you: ~ ch the equations 1 ° << X = β <io °
X = θ <<Λ = ß are defined, in which o (15,30) represents \ the tapered angle of the notch of the head part, ß the taper angle of the nose (16, 31) of the head part, J jump to the pointed converging engaging VOI (24) of the fastening device, and θ is the tapering angle of the engaging notch (27) of the ¹ "fastener, 5. Fastening element according to claims 1 to 4, characterized g e - - 19th 1 · T indicates that vie * "are to eight notches (15, 30) vo ^r hands. 6. Fastening element according to claims 1 to 5, characterized in that the head part consists of a screw head (12) and a concentric threaded one Has shaft (14). 7. Fastening element according to claim 6, characterized in that a flange-shaped disc (13) between the Screw head and the shaft is arranged. 8. Fastening element according to claims 1 to 5, characterized in that the head part has a nut body (28) forms and is provided with a concentric screw hole (29). 9. Fastening element according to claim 8, characterized in that g e k e η η - ζ e i c h η e t that the head part (male portion) at its bottom part has a flange-shaped disc (32). 7430267 5th OB 76