DE2443013A1 - FASTENING ELEMENT - Google Patents

Description

Patent attorneys WILCKEN & LAUFER DR. HUGO WILCKEN · D1PL.-ING. THOMAS WILCKEN DIPL ^ CHEM. DR. WOLFGANG LAUFEF ^LUBECK LOBECK: -; MONKS

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

Fastener

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

There are known screws, the ode a slot head · "have a Phillips head. These types of screws have the disadvantage that the efficiency of the transmission is limited to the torque and that the inner wall of the slot or recess can be easily worn or damaged.

In the conventional screws, nuts or bolts which have a hexaq- "r.alen screw head or body, the so-called" net Arit .swinkel "(drivitni angle) qrofc UNU is 60, the so-called ''Aruriebswinkel" is defined by eme raili-.ile line that accumulates an attacking point duT with a - · ~ tanyentiaU-n line to four contour

509816/0226 ~ ^£> ~

LUBECK I ■ Pray StroO «52-S4 · Vefon (04 V) 7SS ^ ic I MUNICH ti P., tieeenle-Λαβ« '* I Ί-' ■ ** [0 6T ₁ U 7: _t ■

■ i '-k x.imb. j'jl 19? M Bo' -on Commerzbo ik I jb. . BtZ? 30 10022 'I · to N < ¹ O 1 ■ Deu' ^ di · lon «MÜ-ichtn (BU / 'v" ■ - ·>"> o Nr · Τ5 <3>

the fastening device at the point where the force is applied. For this reason, the fastening device (fastener driver) on the outer wall of the screw head to slide, when the screw is tightened or loosened, so that the loss of Dr _e hkr _a ft is increased, and damage to the edge portions or be worn. Due to 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 above-mentioned disadvantages, a screw head has been proposed which has a plurality on its periphery of notches, incisions, grooves and lugs or projections, the lugs being 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 effected, which is designed so that damage and. rapid wear can be caused, its dimensions With regard to its mechanical strength, it should be chosen so as to prevent damage can be prevented even if a full

509816/0226

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

The problem posed could surprisingly be achieved in that several notches are created on the periphery of the cylindrical upper part of the screw head, each of which has a partial circular cross-section and this partial circle is so defi ned that it sets the "drive angle" to O. To achieve this , the center of the partial circle of the 'notch' is placed on a radial line extending from the center of the cross-sectional circle of the upper part of the screw head and within an area of the radial line between the last-mentioned center and A first point of intersection is defined at which two tangential lines intersect. These tangential lines touch the cross-sectional circle of the upper part of the screw head at second intersections where the partial circle of the notches intersects the cross-sectional circle of the upper part of the screw head.

With fasteners of this type no force component ER "testifies that causes slipping of the fastener from the fastener. Therefore, the rotational force of the fixture is completely transferred to cia? Fastener and it comes

Hardly to be damaged Or: to wear of the fastening element.

In those cases in which the center of the partial circle is arranged radially outside of the first point of intersection, as in the case of the screws according to the prior art, the "drive

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angle "values greater than O C an with respect 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 between the first intersection and an arc or chord that connects the second intersection. When the center of the Partial circle within the arch or circular chord is in relation to the center of the cross-sectional circle of the upper screw head part, then the side corners or side edges of the nose can very easily break off and it is also difficult to remove the fastening device to be attached to the fastener.

Preferably in the fastening elements according to the invention Four to eight notches are chosen and in most cases six notches. If the number of notches is less than four, then 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 the lugs and it is also easy to make errors in the dimensions 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 ₀ , d _o 4-. Ir .D ₀ (1)

In the above form t-1 is the number η de ^r notches d to you ^ chrrn-. , <- ■ <■ *

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of the partial circle de "" notch and D the diameter of the transverse cross sectional circle of the male portion.

When the diameter of the partial circle of the notch in this Way is determined, even with full 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 pull -

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

from which the fastening device consists, is standardized so that

2 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 regarded 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 is in the range from 1.5: 1 to 1: 4th 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 balanced when the ratio width of the force-absorbing part (force-transmitted portion) (ie the nose of the fastening element, which is between two adjacent notches of the Fastening element is defined, ) to the force-transmitting part (force-transmitting portion), (ie the projection of the fastening device, which is attached to the notch of the fastening element.

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

Since the width of the projection of the fastening device is essentially 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 hand, the width of the nose is substantially the same as that Arc length of the outer peripheral margin de ^ noses and may therefore can be expressed as follows:

= - 'D _n - (J _n (3)

. η OO ^w

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 expressed by the following equation.

^D o = ^d o = ° ^{'25 D} o

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

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direction lies. For the sake of practicality and the economics will be the diameter of the notch of the partial Circle preferably defined as follows:

4 η 0 = 0 = 3 -rr

The upper part of the screw head preferably runs at an angle from 1 to 10 together with respect to the central axis of the fastener and is more inclined than the corresponding engaging element concave part of the fastening device. The cross section of the lower end of the concave part of the fastening device corresponds to one Cross-section of the upper part of the screw head slightly above the lower end of the same. This type of structure of the fastener enables extremely easy removal of the fastener from the mold after manufacture and also extremely easy attachment 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 with regard to the attachment of the fastener in tight assembly areas that cannot be reached by hand.

The fasteners according to the invention are used in the following Description explained in detail with reference to the accompanying drawings.

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- S.

Fig. 1 is a plan view of a screw or a 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 forms a larger circle 18 on its cross section (see Fig. 4), a flange-like washer 13 which extends radially from the bottom part of the screw head, and a shank provided with a thread which extends axially from the washer of the screw head. Of the

509816/0226

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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 16, 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 trained by the large circle 18 inwardly concave is. The center is denoted by the reference number 0. . ■ ■ ■ _

FIGS. 3 to 5B, it can be seen that the screw head is matched to a "engaging recess or groove 22 12, 20 is formed (driver) in a support member 21 of the fastening device * The recess 22 has a cross-section which fully the has the same cross-section as the screw head 12. The upper part of the holding part 21 has a hole 23 which has a right-angled cross-section A handle (not shown here) can be inserted into the hole 23 so that the fastening device 20 can be rotated.

In the inner wall of the recess 22 there are engaging projections 24 which have an essentially semicircular cross section , which is designed to be complementary to the notches 15 and which engage in the corresponding notches. The effective exaggeration of the drive? Driving torque from the engagement of the tabs 24 of the fastener on the tabs 16 of the screw head requires a "drive angle" to be considered. This "drive angle" is defined by a radial line passing through a point (that is, a force-acting point where the fastener presses the screw head when the screw is tightened or loosened) with a tangential line

509816/0226

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the contour of the recess of the fastening device at this force-acting point. If the "drive angle" is positive with respect to the direction set by the fastener, then a force component is generated which results in insufficient torque being transmitted to the screw head and further causes the fastener to slide off the outer wall of the screw head. Because of this slippage, there is an increased possibility that the side hedges of the noses of the screw head will be worn or damaged. On the other hand, if the "drive angle" is 0 with respect to the direction set by the fastener, the above-mentioned sliding cannot take place and thereby extremely efficient transmission of the rotating force is effected and good engagement of the fastener 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 the "drive angle" is 0 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 .

It can be seen from FIG. 5A that the central point 0 of the semicircle 19 of the engaging projections 24 and, accordingly, of the notches 15

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* 44

is arranged at the intersection of the tangent lines 25 and 25a, the to the larger circle 18 of the blade head 12 at the intersection points P and P are tangential when the semicircle 19 is the larger circle 18 cuts. In this case, the intersection point P becomes the force-acting point F (force-applied point) when the screw head is driven or rotated in the direction indicated by arrow A, and the tangential line to the projection 24 of the fastening device on Point B meet with the radial line OP. In this case

the "drive angle" carries 0 and enables complete transmission the torque from the projection 24 on the nose 16.

5B it can be seen that the central point 0 of the partial circle 19 is arranged on the arc or circular chord 26 and the points of intersection P and P of the largest 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 amounts to the "drive angle" 0 as in the case of the above example.

When the central point 0 of the partial circle 19 is arranged as described above, the "drive ^{angle 11"} is 0 with respect to the direction caused by the fastening device. For this reason, the efficiency of the transmission of the rotational force is extremely increased and the fastening device is prevented from slipping off.

If the central point 0 of the semicircle 19 is located within the arc or circular chord 26, specifically with respect to the central point 0 of the larger circle 18, then the ^M drive winker ^{1 is} also at 0 °. However, the lateral corners of the nose 16 are located strong near the

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

In the present invention, in addition to the precise adjustment the center of the notch semicircle also determines 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 rotational force is completely transmitted from the fastening device to the fastening element.

If the shear or shear forces required for the manufacture of the screws and fastening devices are taken into account, then the ratio of the width of the projection 24 of the fastening device to the width of the nose 16 of the screw in the range from 1: 1 to 1: 4 and preferably in the range from 1: 2 to 1: 3 in order to achieve the Schubbzw. Balance the shear resistance of the screws and fasteners near the points, apply the force and apply the force is applied. The width L of the engaging vor protrusions 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 becomes the ratio between the width I of the nose 16 and the diameter d of the semicircle is defined as follows

ί -ε

or preferably
1 '

3 = 0

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On the other hand, the width I is essentially the same Arc length of the circle 18, which is defined between two adjacent semicircles. thats why

if the latter equation is substituted into the previous equation then is

or preferably

1 · ΊΕ. D / c < 1 ff

4 η O - O = 3 'η

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 _n * d _n < 0.25 D _n

or preferably

°> ^{12 D} o ^ ^d o ^ ^{0 '17 D} o,; ■

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

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

On the other hand, the screws are damaged if d> - ^. IL . D. if

conversely d <-. ίΠ. D then it can damage the Be-O ο π Ο

fastening device come.

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

On the other hand, the engaging projection 24 of the fastening device and the engaging notch 27 run between two
adjacent engaging protrusions is formed with angles

γ and 6 together with respect to the central axis 0-0. It exists
the following relationship between the angles <Λ and ß:

ι * = β > γ = θ

A maximum distance C between the bottom of the notch 15 and the central axis 0-0 of the screw head results in the following relationship
with a maximum distance C between the apex of the engaging projection 24 and the central axis 0-0 of the fastener:

The maximum outer diameter D of the screw head results in the
the following relationship with the maximum inner diameter D of the sicH

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matching concave part 22 of the 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 end of the screw head, is indicated 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 is indicated by Q is specified, then the following relationship will always arise:

Q 4 H

If the fastener is attached to the screw head or fits, then it is normally prevented that the fastener hits the upper surface of the washer and yet the fastener adapts reliably to the screw head at a point slightly above the located at the top of the disc. This prevents the fastening device from being easily detached from the screw head. A screw of this type is formed by pressing or cold forging. The easy removal of the screw from the MetaUform is achieved due to the converging configuration of the molded article, ie the screw head.

Figures 6 and 7 show a nut according to the present invention. This nut consists of a body 28 which has a screw opening 29 in the central part. A plurality of notches 30, lugs 31 and the disc 32 in the outer periphery of the body have the same

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Refinements as shown in FIGS. 1 to 5C.

Fig. 8 shows a further embodiment of a nut according to the Invention. This nut has the same design as shown in FIGS. 6 and 7, but it does not have a washer.

Patent claims: - 17 -

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Claims (9)

. / V Claims M. ) 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, characterized in that the head portion (12, 28) forms a first Kr _e is (18) on its cross section, each of the notches (15, 30) of the head part one at its cross section Partial circle (19) forms, which is curved within the first circle is and . ._. the center (0) of the partial circle on a corresponding radial Line is arranged, which extends from the center (O) of the first circle and within a range of this radial line between the the latter center and a first intersection is defined at which two tangential lines (25, 25a) intersect, the tangential Lines touch the first circle at the second intersection points (P. P) where the first circle intersects the partial 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 - 509816/0226 3. · Fastening element according to claims 1 and 2, 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 1 ■ K. ο _d <. 1 . > r. _D. 5.n. 0 _ ο _ 2 ή ■ 0 is defined where D is the diameter of the first circle represents, d is the diameter of the partial circle, and. η the Number of notches in the head part. 4. Fixing element according to claims 1 to 3, characterized in that the notch (15,30) and the nose (16, 31) of the head part (12, 28) to the central axis (0-0) of the head part are inclined with angles given by the equations 1 ° < (A - ß <io °
X = θ << A = ß are defined, wherein <a represents the tapered angle of the notch (15,30) of the head part, ß the tapered angle of the nose (16, 31) of the head part, f the tapered engaging projection (24) of the fastening device, and θ the tapering angle of the engaging notch (27) of the fastening device. 5. Fastening element according to claims 1 to 4, characterized g e - - 1 Q - 509816/0226 indicates that there are four to eight notches (15, 30) are. 6. Fastening element according to claims 1 to 5, characterized in that the head part consists of a screw head (12) and has a concentric threaded 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 forms a nut body (28) and is provided with a concentric screw hole (29) . 9. Fastening element according to claim 8, characterized in that geke η η - ζ ei ch η e t that the head part (male portion) 'has a flange-shaped disc (32) on its bottom part. 509816/0226