GB2154212A - Holder for the insertion of substantially cylindrical slender tools, in particular twist drills - Google Patents

Abstract

The tool holder has two apertured strips which are disposed one above the other and have holes (6.1, 6.2) arranged in a row along a line (8-8), each hole in one strip being vertically aligned with an associated hole in the other strip. The form of each hole is determined by a base circle whose diameter is slightly larger than the nominal diameter of the tool to be received in the hole and are enlarged by at least one edge cut-out portion (11) which lies beyond the circle. Edge cut-out portions (11) at each hole (6.1) of the upper strip (5.1) are each in diagonally opposite relationship to an edge cut-out portion (11) at the associated hole (6.2) in the lower strip (5.2). The tools stand in a bracket beneath the strips (5.1, 5.2). <IMAGE>

Description

SPECIFICATION Holder for the insertion of substantially cylindrical slender tools in particular twist drills The invention relates to a holder for the insertion of substantially cylindrical slender tools, in particular twist drills, comprising two apertured strips which project from a holder wall on the same side thereof and which are disposed one above the other in the direction of insertion of the tools and the holes in which, for receiving the tools, are arranged in a row with the centres of the holes, on each apertured strip, along an axis which is substantially parallel to the holder wall, and are aligned in the direction of insertion of the tools with a respective one of the holes in the respective other apertured strip and are defined in regard to their hole form substantially by a base circle about the centre of the hole, the inside diameter of said circle being slightly larger than the nominal diameter of the tool which is intended to be received in the hole, and comprising brackets which are disposed on the holder wall in the direction of insertion beneath the apertured strips, the tools when fitted into the apertured strips standing on said brackets.

Holders of that kind are known in various forms and are used in particular as pivotable inserts, made from sheet metal, in boxes or cases which serve for storing a large number of drills in a graded sequence on the basis of the diameters of the successive drills, wherein the holes in the apertured strips or bars are adapted to the diameter of the respective drill which is to be accommodated therein and the diameter of the base circle of each said hole is about two to three tenths of a millimetre larger than the diameter of the respective drill. Such boxes with holders in the form of pivotable inserts are described for example in German patent specification No. 2 461 766.

If the tools have a smooth undamaged shank, no difficulties are involved in fitting the tool with the shank leading into the apertured strips or removing the tool from the apertured strips again, as for that purpose the fact that the diameter of the hole is slightly larger than the diameter of the tool ensures that there is sufficient free clearance between the edge of the hole and the tool. If however the shank of the tool has suffered damage, for example as a result of being gripped in a tool holder such as a drilling chuck or the like, so that projecting edges and/or burrs have been formed thereon, such damage can have the result that the tool jams in the holes in the holder and the cutting edges on the tool result in cuts on the hand or fingers when the tool is to be pulled out of the holder and, in so doing, the hand or finger slips on the tool which is jammed in position.It is not possible simply to increase the diameter of the holes in order to remedy that disadvantage. For, quite apart from the fact that in that case the graduation in respect of diameter of the holes would no longer automatically result in the tools being properly arranged in order in the apertured strips or bars, because a tool for example could also be received in the hole for the tool which is the next thinner tool in the graduated sequence of tools, the tools could take up an inclined position in the holes in the holder, even if they were in their proper order therein, because the free clearance between the tools and the holes in the holder is then larger, and such inclined positioning could be to such a degree that the ends of the tools slip sideways off the brackets and would therefore no longer be securely supported in the holder.Correspondingly increasing the size of the brackets would result in the holder being of larger dimensions, more specifically in particular transversely with respect to the wall thereof. However, increased dimensions of the nature are extremely undesirable, more specifically in particular having regard to the fact that a plurality of holders are generally used in side-by-side relationship in the above-mentioned boxes, and any increase in the size of the holder would be multiplied in its effect on the dimensions of the box. The invention is based on the problem of so designing a holder of the kind set forth in the opening part of this specification that the holes afford adequate free space for even damaged or impaired tools to pass therethrough, while nonetheless the tools cannot take up such an inclined position in the holes that the tools can slip off the brackets.

According to the invention a holder for the insertion of substantially cylindrical slender tools comprises two apertured strips which project from a holder wall on the same side thereof and which are disposed one above the other in the direction of insertion of the tools through holes which, for receiving the tools, are arranged on each apertured strip in a row with the centres of the holes in the row, along a longitudinal axis which is substantially parallel to the holder wall, each hole in one strip being aligned in the direction for insertion of a tool with an associated one of the holes in the other apertured strip and each hole form being determined by a base circle about the centre of the hole with the inside diameter of said circle slightly larger than the nominal diameter of the tool which is intended to be received in the hole, the holder further comprising at least one bracket which is disposed on the holder wall beneath the apertured strips on which the tools can stand when fitted into the holes each hole being enlarged by at least one non-round edge cut-out portion which is disposed beyond the base circle in the form of a wedge configuration which is formed between the circle and a notional square disposed with its sides approximately normal and parallel respectively with respect to the said longitudinal axis of the row of holes and into which the circle is inscribed, and the edge cut-out portion or one such portion of each hole in the upper apertured strip being in opposite relationship to an edge cut-out portion of the respectively associated hole in the lower apertured strip which is disposed on the side of the longitudinal axis of that strip which is remote from the holder wall.

The advance achieved by the present invention is essentially that, although the edge cut-out por tions according to the invention provide the desired larger free space for the tool to pass through in each individual hole, because of their particular configuration and association at the holes which are respectively associated in pairs in the upper and lower apertured strips or bars, the cut-out portions render possible inclined positioning of the tool in the direction of the diagonals of the squares containing the holes, that is to say at a maximum at an angle of 45 with respect to the direction of the row or holes, and with the end of the tool which is towards the bracket, in a direction towards the wall of the holder, which thus forms an abutment for the end of the tool so that in no way can the tool slip off the bracket.At the same time, the edge cut-out portions according to the invention ensure that the tools in adjacent holes in the direction of the row of holes cannot be excessively inclined relative to each other.

A preferred embodiment of the invention is characterised in that the contours of the holes, which are associated together in pairs, in the upper and lower apertured strips, as viewed in projection parallel to the direction of insertion, mutually supplement each other on opposite sides with respect to the closed circle. In that case, an edge cut-out portion in a hole in the upper apertured strip does not overlap with any edge cut-out portion in the associated hole in the lower strip. In spite of the edge cut-out portions, that arrangement provides that the tools which are fitted into the holes are still closely guided.

Desirably, the edge cut-out portions respectively have the shape and area of a complete wedge configuration. Moreover, it is desirable to provide two edge cut-out portions for each hole, in order further to facilitate inserting or withdrawing the tools, in comparison with only one edge cut-portion for each hole. However, three edge cut-out portions per hole are not recommended because in that case only a single edge cut-out portion would be permitted in the respectively associated hole in the other apertured strip or bar.

Examples of the invention are described in greater detail hereinafter by reference to embodiments thereof shown in the accompanying drawings in which: Figure 1 shows a box having two twist drill holders constructed in accordance with the invention, the drills not being shown; Figure 2 shows a plan view of one of the holders of the box shown in Figure 1; Figure 3 shows a view in section taken along line Ill-Ill in Figure 2; Figure 4 shows a view in section taken along line IV-IV in Figure 3; Figure 5 shows a plan on an enlarged scale of part of the holder shown in Figure 2; Figures 6a to 6e show modifications of the arrangement shown in Figure 5.

The box shown in Figure 1 has two holders 1 for the insertion of twist drills (not shown). When the box is closed, the holders 1 with the twist drills inserted therein lie within the box. When the box is opened, the holders 1 with the twist drills are moved up (by means described in out co-pending application No.) into the position shown in Figure 1 by the lid 2 as it pivots upwardly.

As shown in Figures 2 to 4, the holders 1 have two apertured strips of bars 5.1 and 5.2 which project from a holder wall 3 on the same side thereof and which are disposed one above the other in the direction of insertion of the drills, which is indicated by the arrow 4 in Figure 3. The holes 6.1 and 6.2 for accommodating the drills are disposed in a row with their centres 7 on each apertured strip 5.1, 5.2 along an axis which is substantially parallel to the wall 3 and which is indicated by 8-8 in each of Figures 2 and 4.In addition, the holes 6.1 and 6.2 in the strips 5.1 and 5.2 respectively are aligned in the direction of insertion of the tools (arrow 4) with a respective one of the holes 6.2 and 6.1 respectively in the respective other apertured strips 5.2 and 5.1 so that they are associated together in pairs in the apertured strips 5.1 and 5.2 and each drill is guided in a hole 6.1 in the upper strip 5.1 as well as in a hole 6.2 in the lower strip 5.2. Disposed beneath the strips 5.1 and 5.2 in the direction of tool insertion (arrow 4) are brackets 9 which are disposed on the wall 3 of the holder and on which the drills stand, when fitted into the apertured strips 5.1 and 5.2.In regard to their shape, the holes 6.1 and 6.2 are firstly substantially defined by a base circle 10 about the respective centre 7 of the hole, the inside diameter of the circle 10 being slightly larger than the nominal diameter of the drill which is intended to be received in the hole. Each hole 6.1 and 6.2 is increased in sized by virtue of at least one edge cut-out portion 11 which is disposed beyond the circle 10 within one of the four wedge-shaped configurations which are formed between the circle 10 and a square 12 which is disposed with its sides approximately normal and parallel respectively to the line 8-8 on which the holes 6.1, 6.2 are arranged, and in which the circle 10 is inscribed.Insofar as, at the holes 6.1 in the upper apertured strip 5.1, edge cut-out portions 11, in projection parallel to the direction of tool insertion (arrow 4), are disposed in diagonally opposite relationship to an edge cut-out portion 11 at the respectively associated hole 6.2 in the lower apertured strip 5.2. As shown in Figures 5 and 6e, the edge cut-out portions 11 in the upper apertured strip 5.1 are disposed on the side of the line 8-8 which is remote from the wall 3 of the holder. In this case therefore, a drill which is guided in the two holes 6.1 and 6.2 can only take up an inclined position with its end which is towards the bracket inclined towards the wall 3 of the holder, so that the wall serves as an abutment for the end of the drill and prevents the drill from slipping off the bracket 9.

More specifically, in the illustrated embodiments, the edge cut-out portions 11 each have the form and the area of a complete wedge-shaped configuration. In the constructions shown in Figures 6a, 6b and 6e, there is only one respective edge cut-out portion 11 for each hole 6.1 and 6.2 and those cutout portion are disposed on mutually opposite sides of the lines 8-8, at the holes 6.1 and 6.2 which are associated together in pairs. In the embodiments illustrated in Figures 5, 6c and 6d, each hole 6.1 and 6.2 has two cut-out portions 11, although the cut-out portions 11 of the respective upper hole 6.1 are not in diagonally opposite relationship to those of the associated lower hole 6.2, in the projection direction formed by the arrow 4.

In each case, the contours or outlines of the holes 6.1 and 6.2 which are associated together in pairs in the upper and lower apertured strips 5.1 and 52, once again as viewed in projection parallel to the direction of tool insertion (4), mutually supplement each other on opposite sides with respect to the closed circle 10, in other words, in such a way that in the projection direction, no cut-out portion 11 of a hole 6.1 in the upper apertured strip 5.1 is aligned with a cut-out portion 11 of a hole 6.2 in the lower apertured strip 5.2.

Claims (10)

1. A holder for the insertion of substantially cylindrical slender tools, comprising two apertured strips which project from holder wall on the same side thereof and which are disposed one above the other in the direction of insertion of the tools through holes which, for receiving the tools, are arranged on each apertured strip in a row with the centres the holes in the row, along a longitudinal axis which is substantially parallel to the holder wall, each hole in one strip being aligned in the direction for insertion of a tool with an associated one of the holes in the other apertured strip and each hole form being determined by a base circle about the centre of the hole with the inside diameter of said circle slightly larger than the nominal diameter of the tool which is intended to be received in the hole, the holder further comprising at least one bracket which is disposed on the holder wall beneath the apertured strips on which the tools can stand when fitted into the holes each hole being enlargaed by at least one non-round edge cut-out portion which is disposed beyond the base circle in the form of a wedge configuration which is formed between the circle and a notional square disposed with its sides approximately normal and parallel respectively with respect to the said longitudinal axis of the row of holes and into which the circle is inscribed, and the edge cut-out portion or one such portion of each hole in the upper apertured strip being in opposite relationship to an edge cut-out portion of the respectively associated hole in the lower apertured strip which is disposed on the side of the longitudinal axis of that strip which is remote from the holder wall.

2. A holder according to Claim 1, in which the contours of the holes, which are associated together in pairs, in the upper and lower apertured strips, as viewed in projection parallel to the direction of tool insertion, mutually supplement each other on opposite sides with respect to the closed circle.

3. A holder according to Claim 1 or Claim 2, in which the edge cut-out portions each have the shape and the area of the complete wedge configuration defined by the circle and square.

4. A holder according to one of Claims 1 to 3, in which there are two edge cut-out portions for each hole.

5. A holder substantially as herein before described with reference to Figures 2 to 5 of the accompanying drawings.

6. A holder substantially as hereinbefore described with reference to Figure 6a of the accompanying drawings.

7. A holder substantially as hereinbefore described with reference to Figure 6b of the accompanying drawings.

8. A holder substantially as hereinbefore described with reference to Figure 6c of the accompanying drawings.

9. A holder substantially as hereinbefore described with reference to Figure 6d of the accompanying drawings.

10. A holder substantially as hereinbefore described with reference to Figure 6e of the accompanying drawings.