DE6610423U - SHORT SPIRAL GROOVED TAP WITH PRE-TAPPING PART. - Google Patents

Description

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EMUGE-VERIi: Ricliard Glimpel, Lauf adPegnits 3 _e ; _£ -> - -. ~ Rz: ~ -. WÄXing Anaprw * and drawing sfunmt - «Jimmer. - ~ J ^ rcnf "■", ''

Short spiral grooved tap with Yorsclmöid part »

The present invention relates to a short-spiral grooved thread tap with a pre-cutting part. Usually drills of this type are intended to smooth the ax of the pre-cut thread, in particular on the rearward nut flank _p , by means of the ready-cut part, "because the otherwise Z-shaped short spiral of the chip- grooves cause a stuispfeti cutting angle on the thread groove facing the shaft, and the nut cut with such a drill leaves a considerable depth of roughness on the rear flank.

jj Simple drills with pre- and post-cutting part could, however

) the bad position of the nut flank that was torn open at the back

• do not fix «This is how taps became known that

to "try to counteract the problem that precutting racks were arranged, "which at their shafts Thread flanks are machined back "and in alternation

! with the finished cutting tooth strips. It always follows

On a pre-cutting tooth strip a finished blade tooth strip As a further improvement to this drill, the finished cutting tooth strips were ground back axially in the area of the first cut on their tooth face in order to remove the blunt blade angle on the flanks on the shaft side.

With this tool, however, the rough rear thread flank could the cut nut cannot be completely eliminated, because the one between two finished cutting racks lying pre-cutting ridge is only as far as the difference in the radial height of the Chamfer cone between cutting and final cutting tooth ledge let. This radial height difference is very small and hardly has any effect, because the dor pre-cutting number bar is also used following continuous cutting tooth bar by increasing it of the tapered chamfer to make a pre-schnoidarboit Has.

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The invention »oil now using a kurxspiralig grooved tap «in completely smooth thread too on the rear thread flank of the nut, Si · consists in the transition from pre-cutting to Finished cutting part, i.e. from the flank raised on the shank side to the fully formed flank by a chip division that

. being of various kinds katm., being effected, and the transition 4s B «reioh des kögsiigsu A» sahnitt3s «« tar assignment in itself known axially or approximately axially directed special grooves'?! ·

. is located. This ensures that the rear nut flank torn open by the short spiral grooved pre-cutting part is completely smoothed by removing new small chips with cutting teeth at a favorable cutting angle _e

The subject of the invention is shown in the drawing. Σ'Λ hesitates;

Fig »1 shows a short-spiral grooved tap with a pre-cutting part;

Fig.2 the drill seen from the front;

Fig.3 Excerpts from the successive toothed racks sit their thread profile in the area of the i ^ vscliTiit'i ^ ss ix », ÄisiÄE * Jtsxs £ iihrtiti ^ ssrt - iiobsi the shaft-side thread flanks grow to normal wetness.">

α In Fig.1 there is a type of kaching, primarily for blind hole threads, with a short spiral with, for example, 6 flutes ^; Tap shown, the grooves bit can be machined at an incline to the 'Eohrerachse of about 25-60 °. The number of grooves is not self-evident; limited «It can. * ^! also depending on requirements. 2 or be very · · The kurz3piralig grooved tap has, in a known ¥ eiae to. Advantage that he in long. Spa-lure the saving material in the back. Drives off what is particularly "in the case of sackclothes voa out of the ordinary"

^{The tap 1} shown in the drawing has a final cutting part a and a pre-cutting part Ij,! The latter is weaker in the thread flank than the final cutting part

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executed, vob «i but only dl · shaft-side G» wind 9 flank ο In the case of taps with short spiral grooves, the thread flanice facing the shank is covered resulting in a blunt Sehneidwiukel and thereby the cut Thread on this side is given a rough surface. Of the The transition from the pre-cut to the finished part is intended to smooth the torn thread again Requirements for the withdrawal of new chips at the not perfect nut flank gögebem

According to the invention, not the entire Höho should now Tooth flank d can cut a chip smoothing the nut thread on its edge with just one operation - with which the There is a risk of re-tearing - but the edge length of the drilling flank is intended to generate several small chips be divided into districts.

The division can be of various kinds · Xm example in the Fig,? sections of the 6 successive toothed strips of the short-spiral grooved tap from Fig.1 are shown The type of design in Fig «3 divides the aa calibrated wide chip into small chips ·» *

With this arrangement of the exemplary embodiment, in addition to axially or approximately axially directed special grooves f, which cancel the obtuse cutting angle of the shank-side flank, the transition g from the pre-cutting to the finishing quicktoll ± κ area of the tapered gate h is advantageous * This measure is advantageous The security for a smooth thread with thread teeth on the shank-side flank is increased * Among other things, to obtain the most smooth cutting surface possible with thread cutting teeth along the flank edge, a very firm guidance of the thread teeth without any vibration is required. This fixed guidance is given when the thread teeth intended for smoothing are additionally engaged on their outer edges s1: eh * n _f, which is due to the conical chamfer h extending over them *

further advantage of the transition g from the blending to the Finished cutting part in the Boreich of the conical chamfer h is still, the fact that the blind hole taps one before · » must have a relatively short cut · The laying of the transition g into the cutout area h closes one otherwise necessary extension of the not fully developed thread profile

So the seed effect of the new drill is as follows The short spiral grooved «pre-cut part b conveys in long chip locks leave the chip material to the outside but on the rear. Flank of the cut thread α a rough flank. As the drill penetrates, the

* Transition g to the finished part in action, still in the cut part. The rough flank now becomes the fully developed flank with the cutting tooth of the t «step« ο and an axially or approximately axially directed tooth face f and forms an image. the cutting tooth of the The first stage is given a firm guide through its additional cutting work «This is where the rough open Nut flank in the area of the 1st cutting tooth step completely

^. IUJ.X ^ .1 ■> * · .0 * Λ. -A Λ Ä ¥ t -Σ 1 J f Λ. ~ -.Z. 1 pound? Λ C »_

(n ^ xabiivi. nuu AVJigv uoi "κ« <? ciiBViuzaiia | uai "ωχ ν anj.ut) t« _t ü bui ι joins the 1st stage and in this area smooths the Mattern-Äeifimde · So 9S continues with the 3rd and the following Steps until the entire flank that was initially torn open completely smoothed and thus the evil backwards rougher

: Nut flanks with short-spiral grooved taps be r is sided.

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Claims (2)

require Short spiral fluted tap with from the shank forth axially or approximately axially directed to or in the gate reaching special grooves and in the gate Thread flanks machined back on the shank side as a pre-cut part, characterized in that the shank-side flank transition (g) from the front is a finished-cut part is located in the area of the conical gate (h), and this transition (g) from the raised (c) on the shaft side on the fully developed flank (d) is provided with a Spmu subdivision (e) » 2. Tap according to claim 1, characterized in that that the transition (g) from the Vorztua finished school part.1 »i to a gradual growth (e) of the shaft Thread flanks from the core »to the outer diameter on the Normal dimension (d) formed