EP0942807B1 - Screwdriver or screwdriver attachment - Google Patents

Description

The invention relates to a screwdriver or screwdriver bit with one drive, one Output end and an intermediate shaft, the output end in the form of at least three, preferably four, which ribs is profiled from a center section lying around the axis of rotation radially go out, each have a front end, which has an inclination to the axis of rotation, and front and rear flanks, which in the area adjacent to the forehead essentially run parallel to each other, in which area the front flank on a related to the axis of rotation Diametral surface lies, the flanks being adjacent Ribs a longitudinal notch form with one in the lateral surface of a shaft section leaking notch base.

In such known screwdrivers or screwdriver bits (see for example US-A-2 848 024) the ribs are offset, and essentially by the measure of the rib thickness. The a flank, namely the breast flank on the insertion side, lies with the corresponding flank of the opposite Rib (of course in the case of cross ribbing) with this on a common diamond. The associated screw head is decentralized to this Inlets of the ribs matched. The one in the same groove subsequent rear flank is over the insertion depth essentially parallel, but then goes into one concave fillet over so that the notch edge edges at the foot of the completely flat flank on the wall side to meet. The rounding goes over a quarter circle. This leads to a fairly large volume of material clearing in the base area of the output end with a certain Tendency to weaken.

The object of the invention is a generic Screwdriver or screwdriver bit for screwdriving to design more advantageous and stable.

This task is with with a screwdriver or screwdriver bit the features of claims 1 and 2 solved, wherein is turned off that the two flanks, starting from The front area of each rib in the axial direction from each other are groundbreaking curved. That results in a burden better absorbing material distribution in the ribs. It is proposed according to the invention according to claim 2 that the front Flank facing edge of the notch in the further Course of the continuously curved flank section is curved over a smaller circumferential angle than the notch edge of the rear flank. That yields stable rib feet; the latter are rooted in larger Material accumulation in the transition area to the shaft. Both flanks of the rib are involved by: curved in the circumferential direction pointing away from each other are. The curvature of the front flank to let go over a small circumferential angle there is still a steep slope here, against over a correspondingly larger circumferential angle extending curvature of the rear flank of the rib due to the larger material accumulation that occurs there "Strengthens your back" according to your workload. Both sides to bend also provides an advantageous Clamping effect between the cross profile, i.e. output end the screwdriver or screwdriver bit and the cross slot of the associated screw. This will almost self-locking regardless of position.

Beyond the correspondingly handy insertion method there is a long service life, the application of a high torque and above all the emergence lower ejection forces. It is then advantageous to with a screwdriver or screwdriver bit an input end, an output end and an intermediate one Shaft, the output end in shape profiled by at least three, preferably four, ribs is which ribs from one lying around the axis of rotation Radially extend the center section, in each case at the end have a forehead which is inclined to the axis of rotation has, and front and back flanks form which in the area adjacent to the forehead run essentially parallel to each other, in which Area the front flank on one on the Axis-related diametric surface lies, the The flanks of adjacent ribs are longitudinal Make a notch with one in the outer surface of a shaft section tapered notch base that the two flanks in the forehead area of each rib in the circumferential direction are curved away from each other, whereby the notch edge facing the front flank in the further course of the continuously curved Flanks curved over a smaller circumferential angle is as the notch edge, the back flank. It is further proposed according to the invention that the front flank has an additional curvature around the longitudinal direction with projecting radially outer section of the forehead area the flank. Such an embodiment is from Importance. It results from one going in the direction of work, in the most varied Way of creating torsion of the ribs. The also brings undercut radially inwards in the forehead area Flanks. So one is created for that Screw in screws far radially outwards and therefore a particularly leverage point of attack. It is also an advantage, even if the rear one Flank an additional curvature around the longitudinal direction has correspondingly falling back radially outer portion of the forehead area. Overall renders one diagonally in the corresponding Slot section of the cross slot inserting rib, which favors the clamping effect explained above. Then it is advantageous to use a screwdriver or screwdriver bit with one drive end, one output end and an intermediate shaft, the Output end in the form of at least three, preferably four, ribs is profiled, which ribs from one around the center section lying radially extends radially, each have an end face, which a Has inclination to the axis of rotation, and front and form back flanks, which in that of the forehead adjacent area substantially parallel to each other run in which area the front Flank on a diametrical surface related to the axis of rotation lies, the flanks of adjacent ribs form a notch running in the longitudinal direction with one that runs into the lateral surface of a shaft section Notch reason that the two flanks in the forehead area each rib, starting from one in the immersion profile (Phillips) of the screw head entering Parallel flank section, in the axial direction from each other are curved to the ground, the beginning of the curvature in Area of the mouth of the immersion profile. The results in an improved plug centering between Screwdriver or screwdriver bit and screw head. Achieving a conical torque set tool the further measure proves to be advantageous, that the notch base of each notch in the forehead area is inclined at an acute angle to the axis of rotation. That has centering effect and favors the addressed Clamping effect. It is also suggested that the forehead the flanks surface sections of an imaginary truncated cone form. The invention brings further in proposal that the imaginary extension of the axial projection each notch base at a distance on the axis of rotation passes by. The distance corresponds approximately to the measure the smaller circumferential angle of the steeper curved Flank. It is also proposed that the notch reason runs out with notch edges meeting at an acute angle, it is advantageous that the notch edges meet at an angle of approx. 40 °. A advantageous development of the generic screwdriver or screwdriver bit in that the distance between the tip and the start of curvature is smaller than the immersion depth of the screw head into the immersion profile. This ensures an advantageous one Edge between tool and fastener speak screw. It is favorable here that the width the rib at the level of the profile depth of the screw head immersion profile is larger than the mouth width of the Immersion profile. Finally, the invention brings in Proposal that the parallel flank section subsequent curvature surfaces are twisted. So The clamping effect explained above also arises here between the cross profile, i.e. the output end of the screwdriver or screwdriver bit and the cross recess the associated screw. It finally proves found to be favorable that the curvature surfaces on the front and unevenly wound on the back in the same direction are, in the sense of a peripherally stronger Prewinding of the ribs. The screw profile according to the invention is used in aviation. It is common there Use screws only once. The invention Profile is particularly suitable for the screws unscrew because the flanks of the ribs are no planes but curved surfaces. The new geometry is particularly effective when unscrewing not through the center of rotation of the tool extending flank advantageous. That this flank assigned notch edge runs back slightly to the groove base in relation to a parallel plane the rear flank of the associated rib. That at Unscrew necessary to start screwing high torque can be caused by the geometry optimal surface area when torque is applied transfer. Nevertheless, the invention enables Profile at least corresponding to the state of the art tighten the screw well, with the maximum there Torque at the end of the screwing movement.

Fig. 1

einen erfindungsgemäß ausgebildeten Schraubendrehereinsatz in Seitenansicht, vergrößert,

Fig. 2

einen Schraubendrehereinsatz gemäß Stand der Technik, ebenfalls in Seitenansicht sowie vergrößert,

Fig. 3

das weiter vergrößerte Abtriebsende des Schraubendrehereinsatzes nach Fig. 1,

Fig. 4

die Draufsicht auf Fig. 3,

Fig. 5

das weiter vergrößerte Abtriebsende des Schraubendrehereinsatzes gemäß Fig. 2,

Fig. 6

die Draufsicht auf Fig. 5,

Fig. 7

das Abtriebsende des erfindungsgemäßen Schraubendrehereinsatzes in noch weiterer Vergrößerung,

Fig. 8

die Draufsicht auf Fig. 7,

Fig. 9

eine zugehörige Schraube in Seitenansicht, vergrößert,

Fig. 10

die Draufsicht auf diese Schraube,

Fig. 11

einen Schraubendrehereinsatz in Seitenansicht, vergrößert, eine Weiterbildung darstellend,

Fig. 12

die Draufsicht auf Figur 11,

Fig. 13

den Schnitt gemäß Linie XIII-XIII in Figur 12,

Fig. 14

den Schnitt gemäß Linie XIV-XIV in Figur 13 und

Fig. 15

einen Schnitt durch eine Schraube bei einstekkender Rippe des Schraubendrehers.

The subject matter of the invention is explained in more detail below on the basis of an illustrative embodiment. It shows

Fig. 1

a screwdriver bit designed according to the invention in side view, enlarged,

Fig. 2

a screwdriver bit according to the prior art, also in side view and enlarged,

Fig. 3

the further enlarged output end of the screwdriver bit according to Fig. 1,

Fig. 4

the top view of Fig. 3,

Fig. 5

the further enlarged output end of the screwdriver bit according to FIG. 2,

Fig. 6

the top view of Fig. 5,

Fig. 7

the output end of the screwdriver bit according to the invention in a further enlargement,

Fig. 8

the top view of Fig. 7,

Fig. 9

an associated screw in side view, enlarged,

Fig. 10

the top view of this screw,

Fig. 11

a screwdriver insert in side view, enlarged, representing a further development,

Fig. 12

the top view of Figure 11,

Fig. 13

the section along line XIII-XIII in Figure 12,

Fig. 14

the section along line XIV-XIV in Figure 13 and

Fig. 15

a section through a screw when the rib of the screwdriver is inserted.

The screwdriver bit S shown is rod-shaped educated. In this respect it can also a screwdriver right away.

The screwdriver bit S has a drive end 1 and an output end 2, also called working end.

The drive end 1 is provided with an annular groove 3. The tool can be used here, for example Assign the motor screwdriver axially secured.

The turning entrainment in a corresponding chuck is based on the non-circular, specifically hexagonal cross-sectional shape of shaft 4 of screwdriver bit S. The largest length section is in the latter.

The output end 2 is approximately up to the width across flats of the hexagonal cross section and forms one predominantly cylindrical head as a stepped shank section 5 of the tool. The free end of the shaft section 5 goes into a cross profile 6 over. This has four ribs 7. They go one around the geometric axis of rotation x-x of the tool lying center section 8, in essential radial extension and the same Angular distance.

The gaps between the ribs 7 of the cross profile 6 are realized as notches 9. They are asymmetrical V-notches. They are still far beyond the depth of intervention y of the cross profile 6 in the direction of the shaft 4 continues. You end up in a self-notched Base region 10 of the shaft section 5. The aspect ratio from base area 10 to notched zone is approximately 1: 4.

The essentially on the periphery of the center section 8 attached ribs 7 are in relation to their Forehead inclined to the axis of rotation x-x- aligned. On Part of the forehead 11 is at least partially rib-shaped already in the frustoconical Center section 8 over. A cone tip 12 falls with the axis of rotation x-x together.

The ribs 7 each form a front flank 13 and a rear flank 14, based on an insertion direction a screw 15 clockwise. In cross section seen, they run, roughly speaking, parallel to each other (see Fig. 8).

Taking into account a correspondingly extensive Center offset of the ribs 7 results in an alignment the front flanks 13 opposite Ribs 7 essentially in a diametrical D-D. So here, in relation to the axis of rotation x-x, are practical Diametrical surfaces in front.

The center offset and the same width of the ribs 7 can with the same radial distance of the notch 16 the Notches 9 flanks 13, 14 of different widths are formed. The front (13) are dimensioned radially shorter. The ratio is 1: 1.5 (see Fig. 8).

In the prior art, the transition is the inner edge the uncurved flank 13 to the curved flank 14 of the Score 16.

7, the flanks 13, 14 adjacent ribs 7 in approximately the penetration depth y corresponding end area of the ribs 7 in the circumferential direction curved away from each other. That draws on the outer wall side of the head and base area 10 formed shaft section 5 so that that of the front Flank 13 facing notch edge 13 'in further course going in the direction of the shaft 4 the continuously curved flanks 13 is curved over a smaller circumferential angle alpha than the notch edge 14 'which is also continuous continuously curved rear flank 14. This larger circumferential angles are denoted by beta. The Ratio is 1: 3.

The likewise in a concave, essentially continuous curvature notch base 16 each notch 9 runs in the end region of the tool acute-angled to the axis of rotation x-x near the center off, of course related to an axis parallel to the room Axis of rotation x-x, defined there by the front Exit point 16 'of the notch base 16. The zero point the wedge-out course lies in height in the center area 8. Over the section of the depth of penetration, the The end area of the tool is the course of the curvature of the flanks 13 and 14 and that of the notch base 16 to the extent that a slightly converging Alignment of the areas or lines exists. About this can be an advantageous centering plus clamping effect with regard to the cross-sectional contour of a Reach cross slot 17 of screw 15. The corresponding one Phillips 17 is in the head 18 of the Screw 15 (see Fig. 10).

Due to the different circumferential angles Alpha and Beta of the flanks 13, 14 of a rib 7 has this in Working direction a flat fading breast contour (13) as the area of the rear flank 14. There is also a greater accumulation of materials there and thus also the rear area of the widened Rib 7 foot particularly stable. The Working direction is indicated by arrow A in FIG. 7. The larger flanks grip when unscrewing 14 on correspondingly larger counter flanks of the Phillips 17 on.

As can be seen quite clearly from FIG. 8, has the front flank 13 of each rib 7 an additional Curvature, namely around the longitudinal direction of the screwdriver bit S going. That practically leads to a trough of the flank 13 and a clear one Twisting of the ribs 7. This causes the radial to jump outer section 13 '' of the forehead area in the working direction A facing edge 13 is striking. The Distortion angle is designated with gamma and leads peripheral to about 3 ° lead compared to that in FIG. 8 registered vertical diametrals D-D. The through the corresponding twist achieved additional curvature 7 is also particularly relevant to the longitudinal direction vividly.

The mentioned section 13 '' corresponds to the contour Formation of the cross slot 17 is not diagonal Alignment against the corresponding slot counter surface, but with a protruding point of attack at a more favorable lever position.

The rear flank 14 also has an additional, however opposite curvature around the longitudinal direction of the screwdriver bit S. Accordingly there is also a falling back radially outer one Section of the end region of the flank 14 in front, here but going inwards and also a clear one Forming trough of flank 14.

The weakly conical shape of the central section 8 includes the ribs 7 approximately at an angle of 45 ° inclined course, approximately in the form of an imaginary one Truncated cone. The obtuse-angled transition between the portion of the Ribs 7 and the peripherally adjoining, frustoconical side The main area of the ribs 7 is 19 designated.

Regarding the geometry of the notches 9, it should also be noted that the imaginary extension of the axial projection of the notch base 16 with a clear distance z on the axis of rotation x-x passed. The distance z corresponds approximately one third of the radial distance between the tip of the cone and the line of the obtuse-angled transition 19. The sweeping is meant on a level basis.

Referring to Fig. 7, it is clear that the notch reason 16 towards the base area 10 with those meeting at an acute angle Notch edges 13 ', 14' runs out. The one there Meeting point is marked with 20 and coincides with the peripheral end 16 '' of the concave notch base 16 together. The notch edges 13 ', 14' meet in one acute angle of about 40 ° together.

The cross profile 6 can be in the manner shown generate advantageous in the rotary manufacturing process. The corresponding profiler is through the DE patent 19 21 514 known and is here full content included, also for the purpose, characteristics of these documents to include in claims of the present application.

The screwdriver bit shown in Figures 11 to 15 is with regard to the flank geometry trained. The design features relating to the basic principle correspond to those of the basic version the screwdriver bit S or screwdriver, for whatever reason the reference symbols are analogous are used, some without repetitions.

The structure is now such that the two flanks 13, 14 in the forehead area of each rib 7, starting from one in the immersion profile speak cross recess 17 of Screw head 18 entering parallel flank section 7a curved in the axial direction pointing away from each other are. The beginning of the curvature of the rib 7 is 7b designated. It can be a continuous one Connection to the curved parts of the flanks 13, 14 act or a trapezoidal flank section 7c. The wider base of the trapezoidal flank section 7c faces the shaft section 5 of the tool. The The angles of the trapezoidal flanks can be steeper at 13 than at 14.

The start of the curvature lies in the plug connection with the screw 15 7b in the area of the mouth 21 of the immersion profile of the screw head 18, compare FIG. 15. The corresponding taper towards the cone tip 12 of the trapezoidal flank section 7c and the same in the same width as the head subsequent parallel flank section 7a favor the pin assignment due to the initial larger game and then the rich takeaway in the Area of mouth 21.

The cone tip 12 stands from the base 22 of the plug-in profile, the Phillips 17 so from. The ratios are such that the distance between the tip of the cone 12 and the start of curvature 7b is smaller than the immersion depth T in the immersion profile of the screw head 18th

In Figure 15, the corresponding difference is for reasons of better understanding on a baseline related to the transition area between the forehead 11 and the cone-shaped center section 8 marked. From there towards the shaft 5 begins actual load-bearing area of the flanks 13, 14.

A reference plane E-E is therefore placed in FIG. which is the main region on the frustum wall side corresponds to the ribs 7 and is designated 19. Accordingly, the subject is geometric according to further training formed so that the flanks of the parallel flank section 7a lie on an axial length J1. The flanks of the trapezoidal flank section run only after the length J1 7c to that shown in the drawing defined length J2, under two cutter head infeed angles except for a width F2 (cf. Figure 12). The corresponding cutter head infeed angle are given in Figures 13 and 14. The one in figure 13 shown cutter head infeed angle 8.24 °, the cutter head infeed angle shown in FIG. 14 4.7 °. The latter goes out of the line of the Score 16 out. The width F2 of the rib 7 is at the level of the profile depth T of the screw head immersion profile larger than that of the immersion profile.

As can be seen particularly clearly in FIG to the parallel flank section 7a in the direction of Shank 5 adjoining curved surfaces or trapezoidal flanks wounded, on both sides. The on the flank 14 realized twist is to the periphery more emphasized than that in working direction A. Flank 13. In other words: the front and the back surface of the curvature are in the same direction wounded unequally. In Figure 12 is the approach contour from the depth J2 (see Figure 13) in dash-dotted lines Contour shown. Between the rib side solid line and the dash-dotted line extend the curved to the tip 12 Surface sections or trapezoidal flank sections 7c. While the rear flank 14 facing surfaces to the notch 16 continuously taper, those of the front flank 13 neighboring fields tapering to the periphery. From a minimum width F1 shown in FIG Ribs 7 go this on a length section J2 minus J1 relatively strong across the larger width F2. J1 corresponds to one half to one third of J2.

The facing away from the shaft, i.e. streaking at the output end 2 Edges of the flanks 13 lie in the illustrated Four ribs mainly in a common diametral D-D. Which also on this front flank 13 steeper curvature or trapezoidal flank course results from a comparison of the angles entered in FIG. 11, the Values are given there.

Claims (11)

1. Screwdriver or screwdriver bit (S) with a driving and a driven end (1 and 2) and a shank (4) therebetween, wherein the driven end is profiled in the form of at least three, preferably four ribs (7), which ribs (7) extend radially from a centre section (8) located around the axis of rotation (x-x), each have at the end an end face which is inclined to the axis of rotation, and form front and rear flanks (13 or 14) which in the region adjacent to the end face (11) run essentially parallel to each other, in which region the front flank (13) lies on a diametral surface referred to the axis of rotation (x-x) (diametral plane D-D), wherein the flanks (13, 14) of adjacent ribs (7) form a notch (9) running in the longitudinal direction with a notch bottom (16) ending in the generated surface of a shank section, characterised in that the two flanks (13, 14) starting from the edge of the end face (11) of each rib (7) are curved, facing away from each other, wherein the front flank (13) has a curvature around the longitudinal direction with a projecting, radially outer section (13'') of the end face region of the flank (13).
2. Screwdriver or screwdriver bit (S) with a driving and a driven end (1 and 2) and a shank (4) therebetween, wherein the driven end is profiled in the form of at least three, preferably four ribs (7), which ribs (7) extend radially from a centre section (8) located around the axis of rotation (x-x), each have at the end an end face which is inclined to the axis of rotation, and form front and rear flanks (13 or 14) which in the region adjacent to the end face (11) run essentially parallel to each other, in which region the front flank (13) lies on a diametral surface referred to the axis of rotation (x-x) (diametral plane D-D), wherein the flanks (13, 14) of adjacent ribs (7) form a notch (9) running in the longitudinal direction with a notch bottom (16) ending in the generated surface of a shank section, characterised in that the two flanks (13, 14) of each rib are curved, facing away from each other in such a way that the notch edge (13') facing towards the front flank (13) in the continuation of the curved flank (13) is curved in the axial direction towards the notch bottom through a smaller peripheral angle (alpha) than the notch edge (14') of the rear flank (14).
3. Screwdriver or screwdriver bit according to claim 1, characterised in that the notch edge (13') facing towards the front flank (13) in the continuation of the continuously curved flank section (13) is curved through a smaller peripheral angle (alpha) than the notch edge (14') of the rear flank (14).
4. Screwdriver or screwdriver bit according to claim 2 or 3, characterised in that the front flank (13) has an additional curvature around the longitudinal direction with a projecting, radially outer section (13'') of the end face region of the flank (13).
5. Screwdriver or screwdriver bit according to claim 1, 3 or 4, characterised in that the rear flank (14) has an additional curvature around the longitudinal direction with a receding, radially outer section of the end face region of the flank (14).
6. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the two flanks (13) in the end face region of each rib (7), starting from a parallel flank section (7a) entering the insertion profile (17) of a screw head (18) of a screw (14) and directly adjoining the end edge, are curved in the axial direction facing away from each other, wherein the beginning of curvature (7b) is located in the region of the opening (21) of the insertion profile.
7. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the notch bottom (16) of each notch (9) in the end face region is inclined at an acute angle to the axis of rotation (x-x).
8. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the end face (11) of the flanks (13, 14) forms face sections of an imaginary frustoconical surface.
9. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the imaginary extension of the axial projection of each notch bottom (16) runs past the axis of rotation (x-x) at a distance (z).
10. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the notch bottom (16) ends with notch edges (13', 14') meeting at an acute angle.
11. Screwdriver or screwdriver bit according to any of the preceding claims, characterised in that the notch edges (13', 14') meet approximately at an angle of 40°.

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