DE20004772U1 - Device for drilling holes - Google Patents

Description

Device for drilling holes

The invention relates to a device for drilling holes in surfaces coated with a fibrous and/or porous material, with a driven central drill whose diameter is smaller than that of the hole to be drilled.

The present invention was particularly inspired by the problems that arise when switching elements or plug connections, for example for connecting mobile communication devices or the like, have to be introduced into surfaces coated with fibrous and/or porous materials.

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These components, which generally have a diameter between 20 and 35 mm, are often installed in the interior of motor vehicles.

This interior area is generally equipped with corresponding panel elements, dashboards, center consoles or the like, which are covered on the visible side with fibrous and/or porous materials. These panel elements are either plastic or metal elements which are covered with fabrics, leather, imitation leather or the like and may have an insulating layer, padding or the like, for example made of foam, between their actual surface and the material covering them. The installation of plugs or switches in such panel elements is particularly critical, as the panel material can be very easily damaged when using conventional drills, ring saws or milling machines. The panel material made of the fibrous and/or porous material must therefore be removed before drilling into the actual surface of the panel element, as this could otherwise be damaged when working with the drill, ring saw or milling machine.

conditions that exceed the planned diameter of the bore.

In practice, the fibrous and/or porous material is usually cut open and removed before the actual surface of the panel underneath is drilled. Due to the relatively large diameter of the switches and/or plugs, one or more smaller holes are often drilled and the hole suitable for the switch and/or plug, with a relatively large diameter of usually 20 to 35 mm, is then manually worked out using a file or similar.

All of these tasks require a comparatively large amount of time and a comparatively qualified specialist to carry them out.

Since the use of such components, especially electronic connecting elements such as plugs, to supply energy to the devices is increasing, particularly in the context of mobile communication devices or the like,

This results in high costs and a high time commitment for qualified specialist personnel.

Drills that can achieve such large diameters are known, particularly in the field of woodworking technology. These so-called Fostner drills have a central drill tip and cutting elements that protrude from the outside. These usually two cutting elements create a round outer contour in fibrous wood or the like, before cutter-like scraping elements remove the material between the cutting elements and the center drill.

However, these drills are completely unsuitable for the purpose described above, as the cutting edges initially only engage at specific points, usually cause severe damage to the cladding material in question, and flat parts or threads of this cladding material are torn out by the two cutting edges which initially engage at specific points. As this tearing out of parts of the cladding material takes place on both sides of the cutting edges, and as it occurs particularly in the area of the damaged

If the damage to the cutting edges is intensified over a further course of the bore, this can lead to very large-scale damage to the cladding material, which often exceeds the diameter of the actual planned bore.

It is therefore the object of the invention to provide a device for drilling holes in surfaces coated with a fibrous and/or porous material, which ensures that the desired holes can be drilled quickly and easily and that, moreover, the fibrous and/or porous material surrounding the subsequent hole is not damaged.

According to the invention, this object is achieved in that a pressing element with at least the diameter of the bore to be made is arranged around the central drill, wherein a rotationally movable cutting edge, which is effective along an edge of the pressing element, and a spring means effective in the axial direction to the central drill are arranged between the pressing element and the central drill.

The fibrous and/or porous material is pressed together and held in place by the pressing element according to the invention. In particular, in the case of a porous material, for example a layer of foam, the material is pressed together strongly and thus forms a comparatively solid material unit in the area of the pressing element and in the area of the edges of the pressing element. The fibrous and/or porous material is then cut along the edges of the pressing means using the rotating cutting edge. By pressing and holding the fibrous and/or porous material together using the pressing element, a very good cut can be achieved without further cracks forming or parts of the fibrous and/or porous material being torn out of the area surrounding the cut, which later lies outside the bore.

In a very advantageous embodiment of the invention, the cutting edge is designed as part of a cutting insert which has a positive connection with the central drill.

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This ensures that the cutting edge moves simultaneously with the rotating, driven central drill and cuts the material accordingly through a rotary movement.

The cutting insert according to the invention also offers the advantage that it can be easily replaced with a new or, if necessary, differently designed cutting insert. This makes it particularly advantageous to replace used, worn or blunt cutting inserts or, if necessary, the cutting insert can be specifically adapted to the material to be processed. For example, it is conceivable to use a cutting insert with a serrated edge for fabrics or leather, while for porous materials that have a covering layer, a cutting insert with a straight cutting edge should be used.

In a further very advantageous embodiment of the invention, the spring means is arranged between a stop element on the tip of the central bore

opposite side of the central drill and the pressing element.

This results in a structure which makes it possible, after the device has been placed on the cladding element or the like into which the hole is to be made, to press the pressing element on accordingly and then to apply a feed force against the force of the spring means in order to drive the cutting edge or the cutting insert into the material to be machined.

The design of the invention provides in principle that the tip of the central drill is placed on the material to be machined in a manner known per se before the pressing element is placed on it, since the exact position of the position would no longer be recognizable after the pressing element has been placed on it.

An advantageous development of the invention provides that the cutting insert, the spring element, the pressing element and the central drill are at least partially arranged in a guide element, wherein the

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Guide element rests on the side of the stop element facing the tip of the central drill.

The guide element, which can be designed here in particular as a guide sleeve, accommodates both the pressing element and the spring means, the cutting insert and part of the central drill in its interior. This gives the device the necessary stability and ensures that the pressing element and the cutting insert are guided concentrically around the central drill.

In a further very advantageous embodiment of the invention, the pressing element and the guide element can be connected to one another via fastening means. The fastening means are designed in such a way that they only allow an axial movement of the two elements against one another.

It means that the spring means is enclosed between the pressing means and the guide element. This enables a high level of safety of the structure, as it can be ensured that no objects can get into the possibly rotating, in a preferred

In this embodiment, a spiral spring used as a spring means can reach the workpiece. In addition, this creates a compact structure that can be compressed against the force of the spring means, which enables the device to be easily attached, the pressing element to penetrate and the component to be machined to be drilled through by means of a feed force acting against the spring force.

A further advantage is that the pressing element and the guide element cannot rotate against each other. This creates a fixed unit surrounding the rotating cutting edge and the rotating central drill.

Since the cutting edge is only pressed out of the guide sleeve against the spring force after the pressing element has been placed in place, the risk of injury from the cutting edge can be virtually eliminated.

In a further very favorable embodiment of this configuration, the fastening means can have a handle which facilitates the handling of the device according to the invention.

In a particularly advantageous embodiment of the invention, the cutting edge is moved along an inner surface of the pressing element. This ensures that the hole is drilled through the fibrous and/or porous material inside the pressing element. Any damage to the fibrous and/or porous material caused by the cutting edge would only spread towards the center of the hole, since the area around the hole to be drilled is compressed and held securely by the pressing element. However, since the fibrous and/or porous material in the area of the hole to be drilled out and disposed of anyway, damage in this area can be accepted without any problem.

Further advantageous aspects of the invention arise when the cutting edge and a drill bit serving as a central drill are each coated with appropriate hard materials, in particular diamond. This ensures that a large, comparatively long service life of the device according to the invention is ensured and that this device is suitable for

can be used to process all common materials without wearing out too quickly. This hard coating of the cutting edge is particularly useful for drilling holes in sheet metal or similar.

If very hard materials are to be machined very frequently, the cutting insert can also be used only to cut through the fibrous and/or porous material and the hole in the underlying surface, which in this case may consist of a very hard material, can be made using another insert. The other insert is constructed in a similar way to the cutting insert and is designed as a drill or milling insert with a known and conventional design of its effective cutting edge.

Such an approach would also be useful when drilling holes in wooden components clad with the corresponding materials, since the use of a conventional cutting edge could lead to the cutting edge becoming "jammed" in the wooden component.

In a further embodiment of the invention, the pressing element can have a bearing relative to the drill and the cutting insert which interacts with the drill in a form-fitting manner.

This ensures that there is no excessive development of frictional heat between the above-mentioned elements during operation of the device according to the invention.

The device according to the invention can be used in various ways and can be operated with known and conventional drive devices. In particular, it is intended here, together with a pneumatically or electrically driven hand drill, to facilitate the installation of the corresponding electrical elements in vehicle parts covered with fibrous and/or porous materials.

Further advantageous embodiments of the invention emerge from the remaining subclaims and

the embodiment shown in the drawing below.

It shows:

Fig. 1 is a cross-section through a device according to the invention;

Fig. 2 is a view of the device according to the invention according to the arrow II in Fig. 1; and

Fig. 3 a drilling or milling insert for cutting through the surface beneath the fibrous and/or porous material as an alternative to the cutting insert.

Fig. 1 shows a cross section through the device for drilling holes with surfaces coated with a fibrous and/or porous material (not shown). A central drill 1 can be seen, which is designed here only as a drill tip coated with hard materials in the area of its tip la. A particularly favorable hard material is

Diamond has proven to be the best option. However, hard materials based on carbides or similar are also conceivable.

On the side Ib of the drill 1 facing away from the tip la of the central drill 1, the central drill 1 and thus the entire device can be clamped into a corresponding drive unit 2, which is only shown in outline in Fig. 1. In the simplest case, this drive unit 2 can be a conventional drilling machine in a raised form or for manual operation. In addition, this side Ib of the drill 1 has a stop element 3, on the side 3a of which facing the tip la of the drill 1 a guide element 4, in this case a guide sleeve 4, is supported. Inside the guide sleeve 4, which is centrally penetrated by the drill 1, there is a spring means 5, which is designed here as a spiral spring 5.

On the side of the spring means 5 facing away from the guide sleeve 4, the spring means 5 is supported by an intermediate ring 6 on a pressing element 7. The pressing element 7 as well as the spiral spring 5 are also penetrated centrally by the drill 1 and are

do not rotate with the drill 1 during subsequent operation. This can be achieved, for example, by providing the intermediate ring 6 and another intermediate ring (not shown here) resting on the surface 3a of the stop element 3 with an appropriate lubricant, for example grease, in order to ensure that the central drill 1 can rotate relative to the guide sleeve 4, the spring means 5 and the pressing element 7 without great friction.

In the embodiment shown, the spiral spring 5 is clamped in a slightly pre-tensioned state between the guide sleeve 4 and the pressing element 7. The pressing element 7 and the guide sleeve 4 are connected to one another via a fastening means 8. The fastening means 8 engages in a threaded bore 9 in the pressing element 7 and has a handle 10 at its end facing away from the pressing means 7. Between the handle 10 and the area of the fastening means 8 located in the thread 9, the fastening means 8 is guided in at least one elongated hole 11 in the guide sleeve 4 running in the axial direction to the drill 1, so that an axial movement

connection of the pressing element 7 to the guide sleeve 4 is possible.

In addition, a screwable bolt 12 can be arranged opposite the handle 10 in another elongated hole 11'. This screwable bolt 12, which is arranged rotated by 180° relative to the handle 10, prevents the guide sleeve 4 from tilting relative to the pressing element 7, which could otherwise occur due to the one-sided pressure from the spring means 5. At the same time, the handle 10 and the screwable bolt 12 form a unit consisting of the guide sleeve 4 and the pressing element 7, which can no longer be pushed apart by the force of the spring means 5.

Of course, other anti-twisting devices are also possible, for example with grooves, gates or the like.

This structure with the handle 10 and the elongated hole 11 can be seen even more clearly in the side view of the device according to Fig. 2, which is described in more detail below.

In Fig. 1 it can also be seen that a cutting insert 13 is arranged in a pot-shaped recess of the pressing element 7 facing the workpiece to be machined later. This cutting insert 13 has a circumferential cutting edge 14, the diameter of which corresponds at least approximately to the diameter D of the hole to be made in a corresponding material. The cutting insert 13 is connected to the central drill 1 via a corresponding positive connection 15, here a polygonal plug connection, and is carried along by the driven drill 1 when the device is operated. The cutting edge 14 carries out a rotary movement.

Fig. 2 shows the corresponding device again in a side view, where the drive device 2 can be seen here, which, as already mentioned, can be a known drive device 2, such as a hand drill or the like. The axially displaceable connection of the guide sleeve 4 and the pressing element 7 via the elongated hole 11, already described above, can also be seen here again in detail.

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Fig. 3 shows a drilling or milling insert 16, which can be exchanged for the cutting insert 13 in the device under conditions to be explained later. In addition to the receptacle for the positive connection 15, the drilling or milling insert 16 has two openings 17 through which, for example, drill cores or the like that have become jammed inside the insert can be ejected. Comparable holes 17 are of course also conceivable for the cutting insert 13, but are not explicitly shown in Fig. 1.

The drilling of a corresponding hole into the surface covered with the fibrous and/or porous material is now carried out very quickly, easily and reliably in the manner described below:

The device is clamped into the corresponding drive device 2, for example the hand drill. The tip la of the central drill 1 can then be placed at the point at which the center of the hole will later be drilled into the surface covered with the fibrous and/or porous material.

is to be inserted. At this point, the device is still in the state shown in Fig. 1 and Fig. 2, so that the tip la of the central drill 1 can be clearly seen and easily placed in the appropriate place.

If pressure is now applied in the direction of the material to be drilled while the unit according to the invention is driven, whereby the combination of guide sleeve 4 and pressing element 7 can be held by the handle 10, the tip la of the central drill 1 will penetrate this material and shortly thereafter lower pressing edges 7a of the pressing body 7 will be pressed onto the fibrous and/or porous material.

The fibrous and/or porous material is held in place and, in the case of a porous elastic material such as foam, is compressed in the area of these pressing edges 7a of the pressing element 7. From this point on, the device is then compressed against the force of the spring means 5 by an externally applied feed force. This results in an axial relative movement of the guide sleeve 4 with respect to the pressing element 7 as well as

of the central drill 1 and the cutting insert 13, which is positively connected to it and is now also rotating, relative to the pressing element 7. The cutting insert 13 cuts with its cutting edge 14 first through the fibrous and/or porous material and then through the underlying material of the correspondingly coated surface. This creates a hole with the diameter D.

Because the cutting edge 14 is moved along an inner surface 7b of the pressing element 7, the fibrous and/or porous material is cut in a precisely defined area. The cut will be made in the area where the inner surface 7b and the pressing edge 7a meet along an edge 7c. Since the fibrous and/or porous material is pressed together or at least held in place by the pressing edge 7a in this area, the cutting edge 14 can cut the fibrous and/or porous material very precisely and cleanly. Should small irregularities in the cutting edge 14 nevertheless tear particles out of the fibrous and/or porous material, this will mainly occur in the area between the cutting edge 14 and the central

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Drill 1, since the propagation of cracks or surface tears is prevented by the pressing and holding of the fibrous and/or porous material by the pressing edge 7a. However, since the area between the cutting edge 14 and the central drill 1 is waste anyway, it does not matter if the fibrous and/or porous material in this area is destroyed or attacked.

The same applies to the area directly around the drill bit la of the central drill 1. Since the pressing edges 7a of the pressing element 7 are not yet in contact with the material at the time of the first contact between the drill bit 1 or the drill bit la and the material to be machined, damage to the material can also occur here, which can possibly also spread axially. However, with the diameters of approx. 5 mm that are usually selected for such a drill, this damage will not spread so far that it reaches beyond the area of the diameter D planned for the drilling later. Any damage

The conditions therefore also apply to the waste material with the diameter D of the bore.

In the embodiment shown here, due to the cutting edge 14 provided with a corresponding hard material, in particular diamond, it is possible to drill directly through various materials and the corresponding bore with the diameter D is created. For the special application, the installation of electronic plug elements in correspondingly covered elements in a motor vehicle, this diameter D is approximately 28 mm.

As already mentioned, special applications may make it necessary to replace the cutting insert 13 with a corresponding drilling or milling insert 16.

For example, it could be used to drill through wood elements covered with fibrous and/or porous material. Of course, the cutting edge 14, which is coated with hard material, can also work its way through the wood material, but

However, it is much more effective to lift the device 1 from the workpiece to be drilled after the fibrous and/or porous material has been severed by the cutting edge 14 of the cutting insert 13 and then to replace the cutting insert 13 with the drilling or milling insert 16, the toothed cutting edge 18 of which "jams" less easily in wood materials.

The device would then have to be repositioned, whereby it can be easily centered in the same position by the central drill 1. The drilling or milling insert 16 could then be used to saw through the underlying material, in this case wood, quickly, easily and effectively. For this special purpose, the central drill 1 could of course also be designed as a conventional drill, since a long service life can be guaranteed for use in wood materials even without coating the drill tip 1a of the central drill 1 with appropriate hard materials.

For this particular application, it may be useful if the diameter of the cutting insert 13 is slightly larger than the diameter to be inserted later.

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Bore or the diameter of the drilling or milling insert 16. This can prevent particles from being torn out of the already cut fibrous and/or porous material in its lateral edges by any protruding parts on the teeth of the cutting edge 18 of the drilling or milling insert 16, since the drilling or milling insert 16 then no longer has direct contact with the fibrous and/or porous material.

Claims (14)

1. Device for making holes in surfaces covered with a fibrous and/or porous material, with a driven central drill whose diameter is smaller than that of the hole to be made, characterized in that a pressing element (7) with at least the diameter (D) of the hole to be made is arranged around the central drill (1), wherein between the pressing element (7) and the central drill (1) there is arranged a rotationally movable cutting edge (14), which is effective along an edge (7c) of the pressing element (7), and a spring means (5) which is effective in the axial direction to the central drill (1). 2. Device according to claim 1, characterized in that the cutting edge (14) is part of a cutting insert (13) which has a positive connection (15) with the central drill (1). 3. Device according to claim 1 or 2, characterized in that the spring means (5) is arranged between a stop element (3) on the side (1b) of the central drill (1) facing away from the tip (1a) of the central drill (1) and the pressing element (7). 4. Device according to claim 3, characterized in that the cutting insert (13), the spring means (5), the pressing element (7) and the central drill (1) are at least partially arranged in a guide element (4), wherein the guide element (4) rests on the side (3a) of the stop element (3) facing the tip (1a) of the drill (1). 5. Device according to claim 4, characterized in that the pressing element (7) and the guide element (4) are connected to one another via at least one fastening means (8), the pressing element (7) and the guide element (4) are only movable relative to one another in at least approximately an axial direction. 6. Device according to claim 5, characterized in that the at least one fastening means (8) is connected at one end to the pressing element (7), the fastening means (8) being provided at its other end with a handle (10), and the fastening means (8) being guided axially movably with a region lying between these two ends in at least one elongated hole (11, 11') in the guide element (4). 7. Device according to one of claims 1 to 6, characterized in that the cutting edge (14) is movable along an inner surface (7b) of the pressing element (7). 8. Device according to one of claims 1 to 7, characterized in that the central drill (1) is coated with hard materials, in particular diamond. 9. Device according to one of claims 1 to 8, characterized in that the cutting edge (14) is coated with hard materials, in particular diamond. 10. Device according to one of claims 2 to 9, characterized in that the cutting insert (13) can be exchanged for a milling or drilling insert (16). 11. Device according to one of claims 2 to 10, characterized in that the pressing element (7) has a bearing relative to the drill (1) and the cutting insert (13). 12. Device according to claim 11, characterized in that the bearing is formed by a disk-shaped ring (6) provided with lubricant. 13. Device according to one of claims 1 to 12, characterized in that it can be used together with a conventional drive device (2) which receives the drill (1) on its side (1b) facing away from the tip (1a) of the drill (1). 14. Device according to one of claims 1 to 13, characterized in that it is intended for making bores in the diameter range (D) of 16 to 100 mm, preferably 20 to 35 mm.