EP3946792A1

EP3946792A1 - Hole saw, straightening tool for straightening a hole saw and method

Info

Publication number: EP3946792A1
Application number: EP20714964.2A
Authority: EP
Inventors: Richard Alexander BOSKE
Original assignee: Intermetaal IE BV
Current assignee: Intermetaal IE BV
Priority date: 2019-03-25
Filing date: 2020-03-20
Publication date: 2022-02-09
Also published as: DE202019101678U1; WO2020193418A1

Abstract

The invention relates to a hole saw, particularly for sawing a circular hole in a plaster board or similar paper-coated panel, comprising a circular cylindrical main body (2); sawtooth arrangement (12) disposed on a first end face (10) of the main body, comprising a plurality of teeth (14, 16); and an optional base element arranged on a second end face (20) of the main body. Said base element is more particularly a baseplate (4) which can be coupled to a driving means, more particularly a drill, for rotating the hole saw, wherein at least a number of the teeth are bent in the radial direction (R _R ) in such a manner that they protrude inwards and/or outwards from the lateral surface plane (E _M ) of the circular cylindrical main body, and wherein the cross section of the circular cylindrical main body perpendicular to the axis of rotation (A _H ) thereof in the region of the first end face and running along at least one ideal circle (Kl) deviates from an ideal circle by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter. The invention also relates to a straightening tool and a method for producing and, in particular, straightening a hole saw.

Description

HOLE SAW, ALIGNMENT TOOL FOR ALIGNING A HOLE SAW

AND PROCEDURE

description

The present invention relates to a hole saw, in particular for sawing a circular hole in a plasterboard or a similar paper-coated board, comprising a circular cylindrical main body, a saw toothing arranged on a first face end of the main body, comprising a plurality of teeth, and optionally on a second face end the main body arranged bottom element, in particular a special bottom plate, can be coupled to a drive means, in particular a drilling machine, for the rotating movement of the hole saw. The invention also relates to a straightening tool and a method for producing and in particular for straightening a hole saw.

Such hole saws are known from the prior art. They are usually made from a sheet of metal, in which a saw toothing is usually attached to one long side end by means of a milling tool. The saw teeth created in this way are then machined using a bending tool, with the teeth usually being bent intermittently up and down. The pre-machined sheet metal with saw teeth and the pre-bent teeth is then bent into a cylinder, so that either an open main body or a closed circular cylindrical main body with saw teeth at one end face results. The other end face of the main body thus produced is then attached to a base plate which can be coupled to a drive means and in particular a drill. Here it is known to releasably attach the main body to the base plate; But there are also hole saws be known in which the main body is positively attached to the base plate.

The disadvantage of the hole saws manufactured in this way is the lack of concentricity and, in particular, the cross-sectional shape deviating from an ideal circular line, especially at the free end of the main body, i.e. in the area of the saw teeth, which results in insufficient Cutting result, especially with plasterboard. A straightening of such a hole saw in order to achieve an ideal circular cross-sectional shape, in particular at the free end faces and in the area of the saw teeth, is only possible with great effort and therefore not economically viable.

The object of the present invention is therefore to offer a hole saw which is particularly suitable for sawing circular holes in plasterboard or the like paper-coated plate and which has an improved concentricity with inexpensive manufacturability.

This object is achieved by a hole saw according to claim 1 and a straightening tool according to claim 22.

In particular, this object is achieved by a hole saw, in particular for sawing a circular hole in a plasterboard or similar paper-coated board, comprising a circular cylindrical main body; a saw toothing arranged on a first end face of the main body, comprising a plurality of teeth; and a base element, in particular a base plate, optionally arranged on a second end face of the main body, which can be coupled to a drive means, in particular a drilling machine, for the rotating movement of the hole saw, with at least a number of the teeth being bent in the radial direction (RR) in such a way that they protrude inside and / or outside from the lateral surface plane EM of the circular cylindrical main body, and wherein the cross section of the circular cylindrical main body perpendicular to its axis of rotation AH in the area of the first end face and running along at least one ideal circular line Ki, by a maximum of 0.08% of the diameter, preferably deviates from an ideal circular shape by a maximum of 0.05% of the diameter.

In addition, this object is achieved by a straightening tool for producing and in particular straightening a hole saw, in particular of the aforementioned type, and for bending at least one tooth of a saw toothing, provided on a first end face of a substantially circular cylindrical main body of a hole saw, comprising a plurality Teeth, with a base element, in particular a base plate and / or a temporary base element, optionally on a second end face of the main body. ment is arranged, can be coupled to a drive means, in particular a drilling machine, for the rotating movement of the hole saw, the sawtooth bending tool comprising a cylindrical Tn new shape and a complementary cylindrical outer shape, which surrounds the inner shape while forming a shaping gap, with one of the Au ßenform facing outer wall of the inner form and / or on one of the inner form facing inner wall of the outer form at least one bending means is provided, which the at least one tooth and / or at least a portion of the main body in particular when inserting the saw teeth and the first end face of the circular cylindrical The main body is bent into the shaping gap in the radial direction RR in such a way that it protrudes inwards or outwards from the lateral surface plane EH of the circular cylindrical main body.

We also achieved the object by a method for producing a hole saw, in particular for sawing a circular hole in a plasterboard or similar paper-coated board, in particular as described herein, disclosed, comprising the following steps: producing or using a circular cylindrical main body, the Has the following: a on a first face end of the main body angeord designated saw teeth, comprising a plurality of teeth, and an optionally arranged on a second face end of the main body base element, in particular a floor plate, can be coupled to a drive means, in particular a drill, for rotating Movement of the hole saw; Deforming the teeth of the saw teeth on the first face end of the main body by means of a straightening tool, in particular after a straightening tool, as described herein, and optionally simultaneous straightening of the cross-sectional shape of the main body to a circular shape such that at least a number of the teeth in particular in the radial direction (RR) are bent so that they protrude inwards and / or outwards from the lateral surface plane EM of the circular cylindrical main body, and the cross section of the circular cylindrical main body perpendicular to its axis of rotation AH in the area of the first end face and running along at least one ideal circle line Ki, um a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter of the diameter deviates from an ideal circular shape.

The alignment of the cross-sectional shape of the main body to a circular shape can be achieved by deforming the teeth of the saw teeth on the first face end of the main body. by means of the straightening tool.

All process steps are described here with regard to the hole saw and the guide value and are usually not specifically mentioned. All the features of the hole saw or the straightening tool can, however, also be used in conjunction with the method and are only saved for reasons of redundancy and have not been specifically mentioned.

It has been found that by using such a straightening tool and / or bending the teeth after the circular cylindrical main body has been manufactured according to the features mentioned above, a hole saw with a much more precise concentricity can be obtained than is the case with the prior art is known. The same applies if the main body is bent at least in part.

Optionally, the saw teeth are attached or formed after the circular cylindrical main body has been manufactured. In particular, it has been found to be advantageous to bend or round the circular cylindrical main body from a metal strip, in particular from a sheet metal strip, in particular comprising the saw teeth with non-bent teeth, and optionally to weld the free ends together or to connect them equally. The result is a non-directional, essentially circular-cylindrical main body with non-bent teeth at the first end face. It usually has a concentricity that does not meet the requirements for concentricity for a hole saw of the type mentioned above. By subsequently bending the teeth, as will be described in detail here, the cylindrical main body is straightened with regard to its cross-sectional geometry and, in particular, a cross-sectional geometry that deviates only slightly from the ideal circular shape and in particular by a maximum of 0 .08% of the diameter, preferably a maximum of 0.05% of the diameter, deviates from an ideal circular shape. Basically, the above straightening of the teeth, in particular using the straightening tool, can also be used without aiming at the required deviations from the ideal circular shape, since it allows a hole saw to be produced much more easily and quickly.

Optionally, the aim is that the above accuracy is achieved in particular with the outwardly curved teeth. The ideal circle line is optionally on at least one outwardly curved tooth. It is optionally also possible for this accuracy to be achieved in the root area of the teeth and / or in other areas of the main body, the ideal circle line then being applied in this area.

The ideal circle line Ki can optionally run in the foot area of the teeth. This area is defined in detail below. As an alternative or in addition, it is also conceivable that the ideal circle line Ki runs in the area of at least one tooth tip, preferably in the area of at least two tooth tips, and in particular runs through at least one tooth tip, preferably at least two tooth tips.

Optionally, the ideal circle line Ki extends by a maximum of 10 mm, preferably by a maximum of 5 mm from the foot area of at least one tooth in the direction of the base element or the base plate and / or by a maximum of 5 mm, preferably by a maximum of 2 mm from the foot area of at least one tooth in the opposite direction ver to the bottom element runs, and in particular runs through the foot region of at least one tooth.

The root area of a tooth is optionally understood as the area to which another tooth is connected. From a geometrical point of view, the foot area is optionally the area at which the slope of the sawtooth contour has a zero point and / or a minimum and / or the area where two adjacent teeth meet. In this respect, there is an area in which the Foch saw has an ideal circular line when viewed in cross section, that is, an optimal concentricity with regard to the above-mentioned deviations from the ideal circle. This area can vary within a certain distance from the base element, but it can also vary, as indicated above, with respect to the root area of the tooth. Optionally, it is conceivable that the floor element has a similar deviation from the ideal circular line in the top view and it is also optionally conceivable that the entire fox saw has a cross-section in almost all cross-sectional areas (viewed at different distances from the floor element or from the first end face) has such ideal circle line.

It is also conceivable that the ideal circle line Ki runs offset by a maximum of 10 mm, preferably by a maximum of 5 mm, further optionally by a maximum of 2 mm from the tooth tip of at least one tooth in the direction of the base element or the base plate. The ideal circle line optionally runs in a cross-sectional plane perpendicular to the axis of rotation AH of the main body. A plurality of ideal circular lines can be laid on the main body or the hole saw, in particular to determine the concentricity.

The ideal circle optionally runs in a cross-sectional plane perpendicular to the axis of rotation AH of the main body. A circle with the nominal diameter specified for the respective hole saw can be assumed as the ideal circle. If a hole saw with a 50mm diameter is provided, an ideal circle with a 50mm diameter can be assumed. It is also conceivable to determine the diameter of the ideal circle using a measuring method on the hole saw. For this purpose, a number of diameters and / or radii of the hole saw is determined in the area of the ideal circle line, and an average value is determined therefrom. For example, the diameter is determined along the circumference in the area of every nth tooth, where n> 1 and is an integer. The diameter is preferably determined along the circumference in the area of every 5th - 13th tooth, more preferably every 7th - 11th tooth and more preferably every 9th tooth. Averaging the measurement results optionally gives the ideal circle.

The base element can be a base plate, but all other types of elements can also be used which are designed to accommodate a coupling means for connecting a drive means.

It is conceivable to design the main body as a cylinder with an essentially closed cylinder wall. However, at least one opening can also be provided in the cylinder wall. The main body can optionally have at least one slot, and in particular at least one slot, which extends in particular at least partially or completely from the first face end to the second face end and / or vice versa

Optionally, the cross section of the circular cylindrical main body is perpendicular to its rotation axis AH in the area of the first end face and running along at least one ideal circular line Ki, deviating by a maximum of 0.3 mm, preferably a maximum of 0.2 mm from an ideal circular shape. Optionally, at least a number of the teeth are bent in the radial direction (RR) by the introduction of the saw teeth and the first face end of the circular cylindrical main body in a straightening tool in such a way that they protrude inwards and / or outwardly from the one surface plane EM of the circular cylindrical main body.

Optionally, the metal strip is designed in such a way that the teeth are designed to run coplanar to the (jacket) surface of the metal strip before and during the rounding of the metal strip to form the circular cylindrical main body. In the completely rounded state and in particular special during and after the attachment of the base element, the teeth optionally continue to extend coplanar to the lateral surface plane EM of the main body. This surface area is the surface area of the main body including its axial extension.

Optionally, the saw teeth are in particular formed integrally and preferably on an edge contour on the first face end of the circular cylindrical main body. In this context, in particular, it is possible to punch out the teeth from the metal strip or to manufacture the like in a shearing manner.

The following property applies in connection with the invention, but it is also applicable to any other type of main body of a hole saw or a hole saw or a manufacturing process for this, the sawtooth punched or the like is or will be produced. In the case of a punched or similar saw toothing (also referred to as punching in the following), it is optionally conceivable to shape the main body from the metal strip on which the saw toothing is formed so that the side facing the punching tool during the punching process is the inner side of the main body forms. Usually, the metal sheet for punching the saw toothing is placed on a punching table and punched with a punching tool. One or a plurality of teeth can be punched out here. It has been found that the side facing the punching table during this punching process should preferably be arranged on the outside of the main body. The main body is optionally designed in such a way that the side facing the punching tool during the punching of the metal strip forms the inside of the main body. A correspondingly designed hole saw has an improved cutting or sawing effect. Optionally, the circular cylindrical main body is designed as a closed cylinder (with regard to its outer surface). Optionally, a joint seam and in particular a weld seam, via which the free ends of the circular-cylindrical main body bent from the metal strip are welded to one another, is also designed to run between two teeth and in particular in a valley area between two teeth. Optionally, the joining seam runs coaxially to the main axis of extension AH of the main body. This main axis of extension can be the axis of rotation of the main body. It is also conceivable to form the joint seam at an angle thereto and in particular as a spiral or similar helix running ver in the lateral surface of the main body. In such an embodiment, it is conceivable that the free ends of the metal strip do not run at a 90 ° angle to at least one longitudinal side of the metal strip and / or to the floor element, but at an angle or in an orientation that changes over the length. In such a case, the interconnected free ends are designed, for example, as non-straight lines.

A number of teeth are optionally provided. The number of teeth is also optional. In particular in this context it is conceivable that, depending on the main body to be manufactured and in particular depending on the diameter of this main body to be manufactured, a specially provided manufacturing tool and in particular a special punch is used to manufacture the saw teeth. It is also conceivable that the angle of the toothing or the number of teeth per unit length vary depending on the diameter of the main body to be produced. In this way, the position of the joint seam can be guaranteed, particularly in the valley area or between two teeth. In particular, it is conceivable to make the saw toothing by means of punching or a comparable machine production in the metal strip and in a further work step to cut the metal strip to the correct length 1 and in particular in such a way that the planned joint seam comes to rest at the point which it is planned and / or that a full number and in particular an even number of teeth is formed distributed over the circumference. With a suitable choice of the tooth angle, for example, it can be guaranteed that with a special required length of the metal strip (which optionally corresponds to the later circumferential length of the main body) to form a required diameter of a main body, the joint seam will be located exactly between two teeth etc. . It is conceivable that the saw teeth of a hole saw have a plurality of identical tooth blocks arranged one behind the other in the circumferential direction, with a compensation distance being formed between these tooth blocks such that the sum of the lengths of the tooth blocks and the lengths of the compensation distances of the entire circumferential length 1 of the main body corresponds. A tooth block can optionally have at least one tooth, preferably at least two teeth, further optionally at least four teeth and in particular optionally at least six teeth. A block-wise arrangement of the teeth it allows simple production by means of block-wise production of the tooth blocks and in particular special means of a prefabricated tool for producing the teeth of a block. Here, for example, a tool can be used for punching with a fixed number and spacing of the teeth. By appropriately spacing the tooth blocks relative to one another while forming the compensating distance, the required length 1 of the metal strip can be achieved with, in particular, a uniform arrangement of the tooth blocks and / or the teeth. Preferably, if there are several compensating spacings, these are essentially identical. The tooth blocks preferably have an even number of teeth. The features mentioned above and in the following in this context can also be provided on their own on a hole saw, and in particular on a standard hole saw, in particular for sawing a circular hole in a plasterboard or similar paper-coated board, this comprising a circular cylindrical main body; a saw toothing arranged on a first end face of the main body, comprising a plurality of teeth; and a base element, in particular a base plate, optionally arranged on a second end face of the main body, which can be coupled to a drive means, in particular a drilling machine, for the rotating movement of the hole saw, with at least a number of the teeth being bent in the radial direction in such a way that they are inwardly and / or protrude from the outside of the surface plane EM of the circular cylindrical main body. Further embodiments of the hole saw mentioned here can be combined with this.

It is conceivable that the compensation distance is defined as a tooth distance between the last tooth of a preceding tooth block and the first tooth of a following tooth block and is different from the tooth distances of the teeth within the tooth block. In a particular embodiment, the tooth spacing between the teeth of the blocks must also be zero, so that one tooth merges directly into the next. This also applies to the compensation distance.

In this respect, the invention also relates to a set of different hole saws, which are characterized in that they have different sawtooth angles, in particular in order to ensure the correct positioning of the joint between two teeth. It is also true here that these features can also be provided on a standard hole saw. Further embodiments of the hole saw mentioned here can be combined with this.

Optionally, it is conceivable that the teeth protrude alternately inwards and outwards from the lateral surface plane EH of the circular-cylindrical main body or are bent inwards and outwards. Optionally, the teeth are distributed rotationally symmetrically, bent inwards and outwards, and arranged on the first end face of the main body. It is conceivable to form at least one tooth bent inwards, followed by at least one tooth bent outwards. This pattern can be continued uniformly but also with different numbers in the circumferential direction.

Optionally, the teeth are inward by 0.5 mm to 0.1 mm, preferably by 0.4 mm to 0.2 mm, more preferably by 0.3 mm, and / or outward by 0.7 mm to 0, 3 mm, preferably by 0.6 mm to 0.4 mm and more preferably by 0.5 mm, protruding from the surface area of the circular cylindrical main body or bent inwards or outwards outside and inside means that in relation on the completely rounded main body in the direction of the center, i.e. inward, or away from the center, i.e. outward.

At least one tooth is optional, and in particular all the teeth of the saw toothing are not shaped to run straight at least in the root area of the tooth when viewed in cross section, and in particular are curved. Optionally, they have a circular arch shape FG in the foot area, which is complementary to the ideal circular line Ki. This optionally means that when the teeth are bent, the curvature or circular arc shape created in the tooth by the round shape of the metal strip is at least retained or changed to the ideal circle line Ki by the above-mentioned straightening tool. Depending on the straightening tool used, This will be discussed in detail in the following, it is possible to change the shape of the tooth in the foot area in different areas. It is possible, as seen in cross section, to provide the tooth with an arched shape, a meandering shape, a corrugated shape, a multiple curved shape, a shape corresponding to a polygon structure with continuous or angular development or any other non-straight shape. It is conceivable that at least one tooth, in particular in the foot area, viewed in the radial direction outward, is concave at least in sections. . It is conceivable that at least one tooth, in particular in the root area, viewed in the radial direction outward, is at least partially convex. It is conceivable that the essential shape of the tooth, in particular in its foot area, is formed when the main body is rounded. Here, too, the features of this section are also provided on their own on a standard hole saw. Further embodiments of the hole saw mentioned here can be combined with this.

It is conceivable to provide at least one cut material channel on the wall of the main body, and in detail on the inner wall and / or outer wall of the main body, from the area of the first face end, and in particular adjacent to the saw teeth, at least partially in the direction of the second face end runs and is designed such that it transports cut material from the saw teeth in the direction of the second face end in the sawing operation. The cut material channel can run coaxially to the rotation axis or main axis of the hole saw. However, it can also be designed to run helically or at an angle to it. It is conceivable to design the straightening tool in such a way that such a cut material channel is pressed into the main body when the teeth are straightened.

The straightening tool can be designed so that at least one channel press extension is provided on an outer wall of the inner shape facing the outer shape and / or on an inner wall of the outer shape facing the inner shape, which extends a part of the wall of the main body, especially when the saw teeth and the first end face of the circular cylindrical main body in the shaping gap, bent in such a way in the radial direction RR that it protrudes in a channel-like manner inwards or outwards from the surface plane EH of the circular cylindrical main body. The circular cylindrical main body optionally has a diameter D of 5 mm to 300 mm, preferably 15 mm to 210 mm, in particular in the area of the first end face. The same optionally applies to the floor element and in particular the floor plate.

It is optionally provided that at least some of the teeth have a paper cutting geometry in order to ensure an optimal cutting effect when cutting or sawing holes in plasterboard or similar paper-coated panels.

Optionally, it is conceivable to materially connect the base element to the circular cylindrical main body and in particular to weld it. This guarantees a secure connection of the base element to the main body and in particular an optimized straightening of the circular cross-section during and / or by the bending of the teeth.

The circular cylindrical main body or the aforementioned metal strip is vorzugswei se made of a homogeneous metal and in particular of a hardened metal. It is also possible to provide bimetals, in which case high-strength metals can be provided, in particular in the area of the saw teeth. It has been found, however, that when homogeneous metals are used to form the metal strip, the main body or the hole saw can achieve very good concentricity.

As mentioned, the present invention also relates to a straightening tool for bending at least one tooth, as is described here, and in particular a tooth of the hole saw described here. The straightening tool can also be used with the Stan dart hole saw described here. Since it has been found that, precisely by bending the tooth after the main body has been completed, a concentricity direction can be achieved that was previously not known from the prior art, the straightening tool can also be referred to as a straightening tool for producing a concentricity for a hole saw the.

It has also been found that by bending the teeth after bending the main body, a curved cross-sectional shape can be achieved in the teeth, especially in their foot area, whereby when the teeth are bent themselves better straightening and an ideal circle line in cross section close to the shape of the ideal circle can be achieved.

The straightening tool according to the invention is dedicated to this task. It has an inner shape that is surrounded by a complementary outer shape in such a way that a shaping gap results, into which the main body, with the saw teeth and the first end face first, and with not bent teeth can be inserted and in particular pressed, whereby at least some of the teeth bend and the cross-sectional shape of the main body is directed towards the ideal circular shape.

Optionally, the main body connected to the base element is coupled to a press tool, in particular screwed, via which the main body and in particular the saw teeth and the first face end can be pressed into the shaping gap. When pressing into the shaping gap, the teeth that were not initially bent come into contact with the bending means (s), so that the desired deformation of the teeth occurs.

It is conceivable to bend at least one tooth, in particular a certain number of teeth, or else all teeth of the saw toothing inwards and / or outwards.

Optionally, the straightening tool is designed in such a way that it bends the at least one tooth, in particular when inserting the saw teeth and the first face end of the circular cylindrical main body into the shaping gap, in the radial direction RR such that it protrudes inward or outward from the surface plane EH of the circular cylindrical main body , and the circular cylindrical main body viewed in cross section perpendicular to its axis of rotation AH, in the area of the first end face and in particular running in cross section along at least one ideal circle line Ki, in particular adjacent to the foot area of the teeth and / or in the area of at least one tooth tip Circular shape forces, in particular having an ideal circular line that deviates from an ideal circular shape by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter, and in particular by a maximum of 0.3 mm, preferably by a maximum of 0.2 mm from a deviates from the ideal circular shape . The radial direction RR described here is optionally understood to mean the direction that is coaxial to the radius of the main body runs. However, it can optionally also deviate from this within a range of ± 50 °. The radial direction R _R can therefore run both inwards and outwards (with respect to the center of the main body). The result is an inwardly or outwardly curved tooth which then just protrudes inward or outward from the lateral surface plane EH of the circular cylindrical main body.

Optionally, bending means are alternately formed on the outer wall and the inner wall in the circumferential direction of the shaping gap. Different types of bending at least one or more teeth inwards and outwards have already been mentioned above. The same applies here with regard to the arrangement of the bending means. It is expressly referred to. In particular, several bending means can be provided in order to bend several teeth. For the purpose of bending, the bending means can be designed to be coupling in force on one side, but also on two or more sides with at least one tooth.

Optionally, the bending means has at least one pressing surface, which is brought into force coupling with the tooth when the saw teeth and the first face end of the circular cylindrical main body are inserted into the shaping gap, whereby the tooth is bent ver. A plurality of pressing surfaces can also be provided which give the tooth a curved, in particular a three-dimensional shape. So it is conceivable to bend the tooth along a radial axis selling through the center of the main body and / or along a tangential axis and / or a vertical axis, coaxially to the main axis of extension of the main body.

The pressing surface is preferably designed in such a way that when the tooth is introduced into the shaping gap, the tooth slides along the pressing surface and is thus successively bent into its final shape.

Optionally, the width of the pressing surface BB of the bending means, viewed in the circumferential direction RK, corresponds to the root width Bz of the tooth. It is also conceivable that the width BB is narrower by a maximum of 1 mm, preferably by a maximum of 0.5 mm. It is also conceivable to arrange a plurality of pressing surfaces in such a way that they have a total width that corresponds to these specifications. Optionally, viewed in cross section, the pressing surface has a circular arc shape FG or a similar single or multiple curved shape deviating from a straight line and in particular a circular arc shape FG which is complementary to the ideal circle line Ki. Here, too, reference is made to what is mentioned in relation to the shape of the tooth; the pressing surface can have a corresponding shape so that the described shape of the tooth is achieved.

Optionally, the pressing surface has a wedge surface, and in particular a wedge surface formed on a bending projection. The wedge surface is designed in such a way that the tooth is bent by the insertion of the tooth and sliding along the wedge surface.

Optionally, the bending means has at least one wedge surface which extends as a rising ramp in the direction of the insertion direction EE. The ramp is optionally designed to be linear, but it is also conceivable to provide different angles of incline, in particular with a steady development.

It is also conceivable to design the bending means in such a way that the tooth is held from both sides, that is to say from the outside and the inside, during the bending process or is forced into a press fit on both sides. So it is conceivable to provide a bending means on the inner wall and a complementary bending means on the outside, both bending means come into force coupling with the tooth to be deformed in order to guide or bend the tooth. A bending means can also be designed in such a way that it fulfills these requirements. At least one bending means can be provided in such a way that it counteracts dents, kinks or similar deformations resulting from a bending process of another bending means.

Optionally, the straightening tool is designed in such a way that it bends at least one tooth around a tangential axis that runs tangentially to the shaping gap and / or tangentially to the cross-section line of the skin body. Optionally, at least one tooth, optionally all teeth of the hole saw, are bent around such an axis or an axis running coaxially thereto. The straightening tool is designed in such a way that optionally only the tooth is bent. Optionally, the bending tool can be designed so that the lateral surface parts of the The main body cannot be bent in the radial direction, that is to say about a tangential axis or an axis running coaxially thereto, and in particular does not protrude from the lateral surface of the main body after the bending.

In order to produce the hole saw according to the invention, the following method is proposed:

Optionally, shaping, in particular punching or similar shaping of a saw toothing from a metal strip;

Furthermore, optionally round shaping of the metal strip to form an essentially circular-cylindrical main body and optionally connecting the free ends of the metal strip with a joining process and in particular welding; As already mentioned above, the main body can also have at least one opening and, in particular, at least one slot. In particular, the free ends do not necessarily have to be connected to one another and / or be in contact.

Optionally, mounting a base element, in particular a base plate, on the main body on a second end face of the main body;

In addition to the optional steps above, the method comprises at least the following step: Using the main body or another main body produced as described above, deforming the teeth of the saw teeth on the first end face of the main body by means of a straightening tool and optionally simultaneously straightening the cross-sectional shape of the main body a circular shape according to the parameters mentioned here.

In detail, a method for producing a hole saw, in particular for sawing a circular hole in a plasterboard or similar paper-coated board, in particular as described herein, is disclosed, comprising the following steps: producing or using a circular cylindrical main body which has: a Saw teeth arranged on a first face end of the main body, comprising a plurality of teeth, and a base element, in particular a base plate, optionally arranged on a second face end of the main body, can be coupled with a drive means, in particular a drill, for rotating the hole saw; Deforming the teeth of the saw teeth on the first face end of the main body by means of a straightening tool, in particular after a straightening tool, as it is described here, and optionally simultaneous straightening of the cross-sectional shape of the main body to a circular shape such that at least a number of the teeth in particular are bent in the radial direction (RR) so that they protrude inwards and / or outwards from the lateral surface plane EM of the circular cylindrical main body, and the cross section of the circular cylindrical main body perpendicular to its axis of rotation AH in the area of the first end face and running along at least one ideal circular line Ki deviates from an ideal circular shape by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter of the diameter.

The straightening of the cross-sectional shape of the main body to a circular shape can be done by deforming the teeth of the saw teeth on the first end face of the main body by means of the straightening tool.

It is optionally possible to provide for a hardening process after the teeth have been deformed. Optionally, it is also possible, after the round shaping, for example rolling or bending of the sheet metal strip to form the circular-cylindrical main cylinder, to perform a corrective punching for roundness of the resulting main body. Optionally, the main body can be closed or open along its lateral surface.

With regard to the floor element, it is conceivable to design the floor element as a punched floor element. But it is also possible to produce a milled or the like machined floor element.

To accommodate the floor element in a drive tool and / or in the Pressmit tel for introducing the main body into the straightening tool, at least one thread or similar receiving means are optionally inserted into the floor element. After a lead of this receiving means, it is conceivable, and particularly advantageous with regard to the concentricity, to twist off the bottom element at an outer edge region.

The straightening tool optionally has a pressing device to which the hole saw is attached. to introduce them or the saw teeth and the first face end into the shaping gap and to bend at least one tooth or to align the cross-sectional line of the main body, especially in the area of the first face end, to an ideal circle according to the specifications mentioned herein .

Further embodiments of the invention emerge from the subclaims. It should be made clear that all of the features mentioned herein are also used on their own in a hole saw and / or a manufacturing method for this or a straightening tool for their manufacture and can be the subject of divisional applications. In the following, the invention is described on the basis of exemplary embodiments, which are explained in more detail by the accompanying drawings. These show schematically:

1 shows a three-dimensional representation of an embodiment of the hole saw according to the invention;

FIG. 2 shows a view of the embodiment according to FIG. 1;

FIG. 3 shows a plan view of the embodiment according to FIG. 1;

FIG. 4 shows a cross section according to the cutting line shown in FIG. 2;

FIG. 5 shows a detailed view according to the sectional line shown in FIG. 4;

6 shows an end view of the metal sheet according to FIG. 7 for producing the circular hole saw according to FIG. 1;

FIG. 7 shows a view of a metal sheet for producing the circular hole saw according to FIG. 1; FIG.

FIG. 8 shows a cross section through a floor element, in particular a floor plate from the embodiment according to FIG. 1;

FIG. 9 shows a detailed illustration according to the sectional guide shown in FIG. 8; FIG. 10 shows a detailed cross-section through a saw toothing according to the sectional line shown in FIG. 7;

11 shows a three-dimensional representation of an embodiment of a straightening tool;

FIG. 12 shows a detailed view of the embodiment according to FIG. 11;

13 shows a detailed view of an outer shape of the embodiment according to FIG. 11;

14 shows a detailed view of an inner shape of the embodiment according to FIG. 11,

15-17 a representation of a measuring method for determining the ideal circle deviation; and

18-20 different embodiments of the saw teeth.

In the following, the same reference numbers are used for identical and identically acting components, with high indices sometimes being used to distinguish them.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning, and in particular a meaning as commonly understood by one of ordinary skill in the art when used in conjunction with the description and the Drawings can be interpreted. It is further understood that terms such as those defined in commonly used dictionaries are interpreted in relation to the technical field relevant here, and not in an idealized or in an exaggeratedly formal sense, unless this is explicitly defined. In certain cases, a detailed description of well-known devices and methods can be dispensed with in order to avoid redundancy in the description. The description of specific embodiments and the terminology used therein are not intended to limit the invention. The singular forms “a”, “der / die / das” may also include the plural forms, unless the context clearly suggests otherwise. The term “and / or” includes any and all combinations of one or more of the associated listed items. It goes without saying that the terms “comprises” and / or “comprising” indicate the presence of named features, but do not exclude the presence or addition of one or more other features. Furthermore, it goes without saying that if a certain step of a method is indicated as following another step, it can directly follow this other step or one or more intermediate steps can be carried out before the certain step is carried out, unless otherwise stated . In the same way, it should be understood that when a connection between structures or components is described, that connection may be made directly or via intermediate structures or components, unless otherwise specified. Reference is made in its entirety to the disclosure content of all publications, patent applications, patents and other literature mentioned here. In the event of a conflict, this specification, including its definitions, applies.

The invention is described here with reference to the accompanying drawings, in which embodiments of the invention are shown. However, the invention can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, the embodiments are set forth herein so that this disclosure will be thorough and complete, and will convey the scope of the invention to those skilled in the art in full but exemplary fashion. The description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are intended to be considered part of the entire written description. In the drawings, the absolute and relative sizes of systems, components, layers, and areas may be exaggerated for the sake of clarity. Embodiments can be described using schematic and / or cross-sectional illustrations, idealized embodiments and intermediate structures of the invention. Relative terms as well as their derivatives should be understood to refer to the orientation as described or shown there in the drawing just discussed. These relative terms are used for a clearer description and do not require that the system has to be set up or operated in a particular orientation, unless it is explicitly stated otherwise. Any of the disclosed devices or parts thereof can be combined together or divided into further parts, if not specifically fish stated otherwise. The mere fact that certain measures are listed in sections or claims that are different from one another is not intended to indicate that a combination of these measures cannot be taken advantageously. In particular, all conceivable combinations of the claims are to be viewed as inherently disclosed. In this specification, words such as “substantially”, “approximately” or “generally / generally” are to be interpreted to include at least deviations of a degree of 10% or less, preferably 5% or less, or deviations from a shape which would fall within the scope of the relevant definition to a person skilled in the art, unless otherwise specified.

For the sake of clarity and for the sake of a stringent description, features are mostly described here as part of one or separate embodiments; however, it goes without saying that the scope of the invention can also include embodiments which have combinations of all or some of the features described.

1 to 10, an embodiment of the hole saw according to the invention is shown in different views and sections including the raw material used for production.

The hole saw 1 is designed in particular for sawing a circular hole in a plasterboard plate or a similar paper-coated plate. It comprises a circular-cylindrical main body 2, at the first face end 10 of which a saw toothing 12 is arranged. This saw toothing comprises a plurality of teeth 14, 16, which in particular can be brought into coupling for sawing the hole with the plasterboard or similar paper-coated plate. The hole can be cut using the saw teeth by turning the hole saw. As is known from the prior art, such a hole saw is preferably coupled to a drill or a similar drive means. For this purpose, corresponding receiving means are provided which can optionally be connected to a floor element, in particular a floor plate 4 of the hole saw 1. It is also conceivable to provide accommodation means on other components of the hole saw in order to connect the hole saw 1 to the drive means.

The hole saw 1 comprises at least a number of teeth which, optionally through the insertion Ren the saw teeth 12 and the first face end 10 of the circular cylindrical main body in a straightening tool 30 (see FIGS. 11 to 14) are bent in the radial direction RR in such a way that they protrude inward and / or outward from the lateral surface EM of the circular cylindrical main body 2. This peculiarity will be discussed in detail below.

In particular, by inserting the hole saw into straightening tool 30 with unbent teeth and by bending the teeth in the straightening tool, straightening of the cross-sectional shape, particularly in the area of the first face end 10, can be achieved so that the cross-section is in the area of an ideal circle line Ki ( see FIGS. 1, 2 and 5) corresponds to a circular shape which deviates by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter, from an ideal circular shape, in particular defined by the diameter. It is optionally conceivable that the cross section in the area of the ideal circular line Ki corresponds to a circular shape which deviates from an ideal circular shape by a maximum of 0.3 mm, preferably a maximum of 0.2 mm. A hole saw with such a circular shape, which corresponds to such an ideal circular shape, is not achieved by the methods known from the prior art or in the case of the hole saws known from the prior art.

It is conceivable that the ideal circle line 1 adjoins the foot region 18 of the teeth 14, 16, i. i.e., is located near the root region 18 of the teeth. A range within which the ideal circle line Ki can lie in relation to the foot region 18 of the teeth is shown exemplarily in FIG. 2, with a lower ideal circle line Kr offset in the direction of the floor element and an upper ideal circle line Kr offset away from the floor element are.

Optionally, it is conceivable that the (lower) ideal circle line Kr runs offset by a maximum of 10 mm, preferably by a maximum of 5 mm, from the foot region 18 of at least one tooth 14, 16 in the direction of the base element 4. It is also conceivable that the (upper) ideal circle line Kr extends offset by a maximum of 5 mm, preferably a maximum of 2 mm, from the foot region 18 of at least one tooth 14, 16 in the direction opposite to the base element 4. Of course, it is also conceivable that the ideal circle line Ki runs through the root region 18 of at least one tooth 14, 16, as is also shown by way of example in FIG. 2. It is too conceivable, as described in the introductory part, that the ideal circle line runs in the area of at least one tooth tip.

As shown in particular in FIGS. 6 and 7, the circular cylindrical main body 2 can be produced from a metal strip, in particular a sheet metal strip 6. This metal strip 6 preferably includes the saw teeth 12 with not bent teeth 14, 16. This means that optionally the teeth before and during the rounding of the Me tallstreifens 6 to form the circular cylindrical main body 2 are coplanar with the surface of the metal strip (here in the plane of the drawing according to FIG ) are designed to run. Only after the metal strip 6 has been shaped to form the main body 2 is the teeth 14, 16 bent in the straightening tool suitable for this purpose and in particular the straightening tool described in FIGS. 11 to 14.

As a result of this straightening, in addition to the bending of the teeth, the cross-section of the main body is also straightened in order to achieve an ideal circular line Ki in the cross-section of the main body that is as close as possible to the ideal circular shape.

As shown in FIG. 7, it is conceivable that the teeth 14, 16 are punched out of the metal strip 6 or are made in a shear manner. This leads to a very simple manufacturing process and guarantees a sharp cutting edge 19, as can be seen in FIG. The saw teeth or at least one tooth are especially designed to cut paper in this connexion.

The circular cylindrical main body 2 has a diameter D of 5 mm to 300 mm, preferably 15 mm to 210 mm, in particular in the region of the first end face 10. This information can optionally be interpreted as an information for the ideal circle. The base element, in particular the base plate 4, can optionally have similar and in particular identical geometries

As shown in FIGS. 8 and 9, the bottom element 4 is preferably a cast or milled component, with a receiving area 5, into which the metal strip can be inserted during bending. The connection between metal strips 6 or circular cylindrical main body 2 and base element 4 is preferably made via a welded connection and in particular a welded connection in the receiving area. Instead of a welded connection, any other similarly acting connection, in particular a material connection, can be used. It is also conceivable to provide a detachable connection.

As shown in FIGS. 1 and 2, the circular cylindrical main body 2 from the Me tallstrip 6, in particular comprising the saw teeth 12 with non-bent teeth 14, 16 has been rounded, the free ends 8 of which are optionally welded together or the like are integrally connected. Optionally, it is particularly conceivable in this context that a joint seam, and in particular a weld seam 9, via which the free ends 8 of the circular cylindrical main body 2 bent from the metal strip 6 are welded together, runs between two teeth 14, 16. In particular, it is conceivable that this joint or weld seam 9 runs in a valley region 15 between two teeth 14, 16 and runs particularly in the foot region 18 of these two teeth 14, 16. As described above, the main body can optionally also have at least one slot, and in particular at least one slot which extends in particular at least partially or completely from the first end 10 to the second end 20 and / or vice versa. In this case, no joint seam is usually provided here.

As shown in FIG. 7, it is conceivable to provide the metal strip 6 with the saw teeth 12, for example by punching or a similar shearing method, and then to cut it to the circumferential length 1 by the protrusion S, in order to ensure that with a Round shapes to the main body 2, the weld 9 (see Fig. 1 and 2) in the valley area 15 between two teeth 14, 15 and / or thus a whole number of teeth is arranged along the circumference.

In the embodiment shown here, the saw teeth are formed integrally and preferably on an edge contour 17 on the first face end 10 of the circular cylindrical main body 2.

As further shown in FIG. 7, the cut-to-length metal strip 6 has a whole number and in particular an even number of teeth. In the event of a uniform change between teeth bent inwards and outwards, this promotes concentricity of the hole saw 1. As also shown in FIG. 7, at least some of the teeth have a Paper cutting geometry.

In the figures 18-20 three different embodiments of saw teeth are shown. 18 shows a saw toothing 12, which has a plurality of identical tooth blocks 22 arranged one behind the other in the circumferential direction of a main body made from the illustrated metal strip 6 or the hole saw made therefrom, a compensation distance 24 being formed in this way between these tooth blocks 22 that the sum of the lengths I22 of the tooth blocks 22 and the lengths I23 of the equilibrium distances 23 corresponds to the entire circumferential length 1 of the main body 2 or the hole saw 1.

Optionally, at least one compensation distance 23 is defined as a tooth distance between the last tooth of a preceding tooth block 22 and the first tooth of a following tooth block 22 ‘and different from the tooth distances 25 of the teeth within at least one tooth block 22; 22 ‘. Optionally, the tooth spacings within at least one tooth block are <2mm, preferably less than 1mm and particularly preferably equal to 0 mm. This means that in this case one tooth is directly connected to the next. Tooth transitions can be rounded, angular or variably geometrically shaped. Fig. 18 shows that the number of teeth in at least one, preferably in all tooth blocks is optionally even. The sum of the lengths I22 and I23 results in the total length 1. In such an embodiment, the tool used to manufacture and in particular special punching a tooth block can optionally also be used with different hole saws 1, i.e. in particular hole saws with different diameters D or circumferential lengths 1 , whereby only the compensation distance 23 has to be adjusted.

The same is shown in FIG. 19, an odd number of teeth 14, 16 being provided in each block as an example. It is also conceivable to provide different tooth blocks 22 in a hole saw 1, that is to say, for example, to combine the tooth blocks 22 from FIG. 18 with the tooth blocks 22 from FIG. 19. Optionally, in general, tooth spacings 25 can be provided between at least two teeth 14, 16. These tooth spacings 25 can have a length of 0 mm or> 0 mm. It is also conceivable, and this is shown in FIG. 20, to adapt the tooth shapes and, in particular, their root widths Bz, for the arrangement of an integral number of teeth over the length L. Teeth with different, in particular at least two different, foot widths or only teeth with the same foot width can be provided on a hole saw.

6 shows the end face of the metal strip 6 which is not bent round, it being evident that the teeth 14, 16 of the saw toothing 12 are not bent before the metal strip 6 is rounded to form the main body 2. This bending takes place only after the metal strip 6 has been rounded to form the main body 2 and optionally after the free ends have been joined and / or after the main body 2 has been mounted and in particular provided with a positive fit on the base element 4.

As described in detail above in particular in the general part, in this embodiment too the teeth 14, 16 are preferably bent inwards and outwards and in particular bent in such a way that they protrude from the outer surface EH of the circular cylindrical main body 2. Optionally, the teeth are bent alternately inwards and outwards.

As shown in particular in Fig. 10, it is possible to bend the teeth inwardly 0.5 mm to 0.1 mm, preferably 0.4 mm to 0.2 mm, and more preferably 0.3 mm. Optionally, every second tooth is bent inwards and in particular in this way inwards. Further optionally, at least one tooth 16 is bent outwards by 0.7 mm to 0.3 mm, preferably by 0.6 mm to 0.4 mm, and more preferably by 0.5 mm, so that it is out of the surface plane of the circular cylindrical main body 2 protrudes outward. This is also shown in FIG. 10.

The aforementioned dimensions of the protruding from the lateral surface plane of the Hauptkör pers 2 preferably relate to the central axes of the respective plane. This is also shown in FIG. 10, the inwardly protruding here being denoted by the reference character i and the outwardly protruding with the reference character a. The values mentioned relate to the inward or outward deviation of the central axis of the lateral surface EH and the "bent" central axis AM of the teeth 14 or 16.

As shown in particular in FIGS. 4 and 5, the method of bending the at least one tooth inwards or outwards, namely after the rounding of the Me tallstreifens 6 to the main body 2, optionally leads to the at least one tooth at least in the foot region 18, viewed in cross section, is not shaped to run straight, but is preferably shaped to be curved. It optionally has a circular arc shape FG, which is complementary to the ideal circle line Ki.

As mentioned, FIGS. 11 to 14 show a possible embodiment of the straightening tool 30 according to the invention for bending the teeth 14, 16 of the hole saw 1 and for rich th the cross-sectional shape to an ideal circular line Ki extending in cross-section close to an ideal circular shape. The straightening tool comprises a cylindrical inner mold 40 and a complementary cylindrical outer mold 50 which surrounds the inner mold 40 while forming a shaping gap 60. On an outer wall 52 of the inner mold 40 facing the outer mold 50 and / or on an inner wall 52 of the outer mold 50 facing the inner mold 40, at least one bending means is provided, which at least one tooth 14, 16, in particular when inserting the saw teeth 12 and the First end face 10 of the circular cylindrical main body 2 is bent into the shaping gap 60 in the radial direction RR (see FIG. 10) in such a way that it protrudes inwards or outwards on the lateral surface plane EH of the circular cylindrical main body. This leads to a straightening of the cross-sectional shape.

As already mentioned, the circular hole saw 1 with the not yet bent teeth 14, 16 can be attached to a pressing means 32 and pressed into the shaping gap 60 via this pressing means, for example a hydraulic press. In the shaping gap 60, the bending means 62 provided on the outer mold 50 and / or the inner mold 40 are preferably designed so that they bend the respective teeth 14, 16 inwards or outwards.

According to the invention, the straightening tool is designed to bend the teeth, but also in such a way that it views the circular-cylindrical main body 2 in cross section perpendicular to its axis of rotation AH, in particular in the area of the first end face 10 and in particular, running in cross section along at least one ideal circular line Ki bordering on the foot area 18 of the teeth 14, 16 forces it into a circular shape that is at most 0.08% of the diameter, preferably at most 0.05% of the diameter of an ideal circular shape, in particular defined by the diameter, deviates and further optionally deviates from this ideal circular shape by a maximum of 0.3 mm, preferably a maximum of 0.2 mm.

For this purpose, the bending means 62 are optionally formed alternately in the circumferential direction RK (see FIG. 12) on the outer wall 42 and the inner wall 52, so that the teeth 14, 16 are alternately bent.

Optionally, the bending means 62 has at least one pressing surface 64, which is brought into force coupling with the respective tooth 14 or 16 to be bent when the saw teeth 12 and the first face end 10 of the circular cylindrical main body 2 are inserted into the shaping gap 60, whereby the tooth is bent becomes.

Optionally, the width BB of the pressing surface 64, viewed along the circumferential direction RK (see FIGS. 13 and 14), corresponds to the root width Bz of the tooth 14, 16 (see FIG. 7). It is also conceivable that the width BB is at most 1 mm, preferably 0.5 mm, narrower than the foot width Bz.

It is optionally conceivable, and this is shown in particular in FIGS. 13 and 14, that the pressing surface 64 has a circular arc shape FG or a similar shape deviating from a straight line, singly or multiply curved shape, or has a circular arc shape FG which is complementary to the ideal circle line Ki. Optionally, it is conceivable that all pressing surfaces 64 of the inner mold and / or the outer mold lie on a circular line which is formed coaxially to the axis of the ideal circular line when the hole saw is inserted into the shaping gap 62.

Optionally, all pressing surfaces 64 of the outer mold lie on a virtual outer pressing surface circle. Optionally, all pressing surfaces of the inner mold lie on a virtual inner pressing surface circle. Pressing surfaces 64 on the outer mold are optionally arranged so that the radius of the outer pressing surface circle extends over the depth of the straightening tool. takes. This means that in the insertion area of the bending tool, the radius of the outer pressing surface circle is optionally larger than, viewed in the direction of insertion, further inside the bending tool. Press surfaces 64 on the inner mold are optionally arranged in such a way that the radius of the inner press surface circle increases over the depth of the straightening tool. This means that in the insertion area of the bending tool, the radius of the inner pressing surface circle is optionally smaller than when viewed in the direction of insertion further inside the bending tool.

Optionally, it is conceivable that the pressing surface 64 has a wedge surface 64, and in particular a wedge surface 64 formed on a bending protrusion 68. This wedge surface 64 can extend as a rising ramp in the direction of the insertion direction RE.

In addition, it is possible for the bending means 62 to be designed in such a way that it forces the at least one tooth 14, 16 into a wide-sided press fit that bends it. In such an embodiment, complementary to the bending means on the inner mold 62, a complementary bending means is optionally provided on the outer mold, which prevents buckling, kinking or similar deformation from the other side when the tooth sliding along the bending means 62 is bent. In this way, for example, different tooth geometries, which for example deviate from the ideal circular line, can be formed in the tooth. Optionally, the bending means 62 are formed such that they form a press channel between the outer mold and the inner mold for each tooth.

FIGS. 15-17 show an example of a possible measuring method for determining the deviation of the cross-sectional shape of the hole saw 1 according to the invention from the ideal circle. To carry out the measuring method, the hole saw 1 is provided with a measuring mandrel or similar measuring element 80. To this end, the hole saw is optionally screwed with its second face end 20 and in particular the base element 4 onto a measuring mandrel 80 or the like is arranged thereon. The measuring mandrel 80 optionally has an optimal concentricity and thus an optimal ideal circular shape. A scanning means 84 is then calibrated onto the measuring mandrel 80 via a scanning element 86. Optionally, the measuring mandrel 80 is placed on a measuring table 82 and the measuring mandrel 80 is scanned via the scanning element 86 of the scanning means 84. Optionally, the measuring mandrel is optionally added. turned together with the hole saw. The scanning means 84 is calibrated to a specific height level via this scanning step. This is, for example, 40 mm, a possible calibration diameter of the measuring mandrel 80. Finally, the same scanning means 84 and / or a further scanning means calibrated complementarily to the scanning means 84 or via the scanning element 86 and / or a scanning element 86 calibrated in a complementary manner is used to measure the circular shape or the ideal circle deviation of the cross section of the hole saw is carried out in particular at the first face end 10 and running along the ideal circle line Ki. For this purpose, the scanning element 86 is optionally located on the main body 2 and optionally on the first end face 10 and further optionally in the area of the teeth 14; 16 and in particular applied to the outwardly curved teeth on the hole saw 1. Depending on the embodiment, the ideal circle line Ki at the foot area of the teeth and / or at the area of the tips can be assumed. Other measurement positions are also conceivable. Optionally, the hole saw can be turned. It is conceivable to scan each tooth and / or each area along the ideal circular line of the main body, in particular by rotating the main body, and thus to determine the existing diameter. However, only every nth tooth can be scanned if n> 1 and where n is an integer. Preferably every 5th - 13th tooth, more preferably every 7th - 11th and more preferably every 9th tooth is scanned. Only certain areas of the ideal circle line, for example certain points on the ideal circle line, can also be scanned. A deviation from an averaged diameter and / or a nominal diameter and thus from the ideal circle can thus be determined from the determined diameters. Depending on the position of the ideal circle line, a deviation in the area of the teeth, the tooth syringes, the foot areas of the teeth or the main body adjoining them, or the main body can be determined at any other point.

Claims

Expectations

1. Hole saw, in particular for sawing a circular hole in a plasterboard plate or the like paper-coated plate, comprising

a circular cylindrical main body (2);

a saw toothing (12) arranged on a first end face (10) of the main body (2), comprising a plurality of teeth (14, 16);

and a base element, in particular a base plate (4), optionally arranged on a second end face (20) of the main body (2), which can be coupled to a drive means, in particular a drilling machine, for rotating the hole saw (1), wherein

at least a number of the teeth (14, 16) are bent in such a way, in particular in the radial direction (RR), that they protrude inwards and / or outwards from the lateral surface plane EM of the circular cylindrical main body (2), and the cross section of the circular cylindrical main body (2) perpendicular to its axis of rotation AH in the area of the first face end (10) and running along at least one ideal circular line Ki, deviates from an ideal circular shape by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter.

2. Hole saw according to claim 1,

that

the ideal circle line Ki runs in the area of the tooth tips and / or in the foot area (18) of the teeth (14, 16), and / or by a maximum of 10 mm, preferably by a maximum of 5 mm from the foot area (18) of at least one tooth (14, 16) in the direction of the bottom element (4) and / or by a maximum of 5 mm, preferably by a maximum of 2 mm from the foot region (18) of at least one tooth (14, 16) in the direction opposite to the bottom element (4), and in particular runs through the root area of at least one tooth (14, 16).

3. Hole saw one of the preceding claims, that

the cross section of the circular cylindrical main body (2) perpendicular to its axis of rotation AH in the area of the first end face (10) and running along at least one ideal circle line Ki deviates from an ideal circular shape by a maximum of 0.3 mm, preferably a maximum of 0.2 mm.

4. Hole saw according to one of the preceding claims,

that

at least a number of the teeth (14, 16) by inserting the saw teeth (12) and the first end face (10) of the circular cylindrical main body (2) in a straightening tool (30) in such a way in the radial direction (RR) that they are bent inwards and / or protrude externally from the lateral surface plane EM of the circular cylindrical main body (2).

5. Hole saw according to one of the preceding claims,

that

the circular cylindrical main body (2) is bent from a metal strip (6), and in particular a sheet metal strip, in particular comprising the saw teeth (12) with non-bent teeth (14, 16).

6. Hole saw according to one of the preceding claims,

g that

free ends (8) of the metal strip (6) are welded to one another or the like are materially connected to one another.

7. Hole saw according to one of the preceding claims,

that

the saw toothing (12) is formed in particular integrally and preferably on an edge contour (17) on the first end face (10) of the circular cylindrical main body (2).

8. Hole saw according to one of the preceding claims,

that

the teeth (14, 16) are punched out of the metal strip (6) or are manufactured in a shear manner.

9. Hole saw according to one of the preceding claims, in particular claim 8, that

the main body is round-shaped from the metal strip (6) on which the saw teeth are punched out or the like is manufactured in a shearing manner that the side of the metal strip which faces a punching tool producing the saw teeth in a shearing manner during the punching process forms the inside of the main body.

10. Hole saw according to one of the preceding claims,

that

a joint seam and in particular a weld seam (9), via which the ends (8) of the circular cylindrical main body (2) bent from a metal strip (6) are welded together, between two teeth (14, 16) and in particular in a valley (15) runs between two teeth (14, 16).

11. Hole saw according to one of the preceding claims,

that

the saw toothing (12) in the circumferential direction has a plurality of identical tooth blocks (22) arranged one behind the other, with a compensation distance (24) being formed between these tooth blocks (22) such that the sum of the lengths I22 of the tooth blocks (22) and the lengths I23 corresponds to the compensation distances (23) of the entire circumferential length 1 of the main body (2), and where optional

the compensation distance (23) is defined as a tooth distance between the last tooth of a preceding tooth block (22) and the first tooth of a following tooth block (22 ') and is different from the tooth distances (25) of the teeth within the tooth block (22; 22') ).

12. Hole saw according to one of the preceding claims,

that

the base element (4) with the circular cylindrical main body (2) cohesively connected ver and in particular is welded.

13. Hole saw according to one of the preceding claims,

that

the teeth (14, 16) inwards by 0.5 mm - 0.1 mm, preferably by 0.4 mm - 0.2 mm, more preferably by 0.3 mm, and / or outwards by 0.7 mm - 0.3 mm, preferably by 0.6 mm - 0.4 mm and more preferably by 0.5 mm from the surface plane of the circular cylindrical main body (2) protrude.

14. Hole saw according to one of the preceding claims,

that

at least one tooth (14, 16) of the saw toothing (12) at least in the root area (18) of the tooth (14, 16) is not straight, preferably curved, and in particular has a circular arc shape FG that leads to the idea - the circle line Ki is complementary.

15. Straightening tool for producing and in particular straightening a hole saw and for bending at least one tooth (14, 16) of a saw toothing (12), provided on a first end face (10) of a circular cylindrical main body (2) of a hole saw (1), comprising a plurality on teeth (14, 16), with a base element, in particular a base plate (4) being optionally arranged on a second face end (2) of the main body (2), which can be coupled to a drive means, in particular a drilling machine, for the rotating movement of the hole saw,

the saw-tooth bending tool including:

a cylindrical inner mold (40) and a complementary cylindrical outer shape (50) which surrounds the inner mold (40) while forming a shaping gap (60), with the inner wall (42) facing the outer mold (50) Form (40) and / or on one of the inner form (40) facing inner wall (52) of the outer form (50) at least one bending means (62) is provided, which we at least one tooth (14, 16) especially when inserting the saw teeth and the first end face of the circular cylindrical main body (2) in the form Training gap (60) is bent in the radial direction RR in such a way that it protrudes inwards or outwards from the lateral surface plane EH of the circular cylindrical main body (2).

16. Straightening tool according to claim 15,

that

the straightening tool (30) is designed in such a way that it bends the at least one tooth (14, 16) in the radial direction RR in particular when the saw teeth and the first end face of the circular cylindrical main body (2) are inserted into the shaping gap (60) in such a way that it protrudes inwards or outwards from the lateral surface plane EH of the circular cylindrical main body (2), and the circular cylindrical main body (2) viewed in cross section perpendicular to its axis of rotation AH, in particular in the area of the first end face (10) and in particular running in cross section along an ideal circular line Ki adjoining the foot region (18) of the teeth (14, 16), forcing it into a circular shape which by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter of an ideal circular shape, in particular defined by the diameter , deviates and optionally deviates from this ideal circular shape by a maximum of 0.3 mm, preferably a maximum of 0.2 mm.

17. Straightening tool according to one of the preceding claims 15 or 16,

that

Bending means (62) are formed alternately in the circumferential direction of the shaping gap (60) on the outer wall (42) and the inner wall (52).

18. Straightening tool according to one of the preceding claims 15-17,

that

the bending means (62) has at least one pressing surface (64) which, when the saw teeth and the first end face (10) of the circular cylindrical main body (2) are introduced into the shaping gap (60) with the tooth (14, 16), are brought into force coupling causing the tooth to be bent.

19. Straightening tool according to one of the preceding claims 15-18,

that the width (b) of the pressing surface (64) along the circumferential direction RK corresponds to the root width Bz of the tooth (14, 16) or is narrower by a maximum of 1 mm, preferably 0.5 mm.

20. Straightening tool according to one of the preceding claims 15-19,

d a u r c h u n n n n n n e i c h e te that

Viewed in cross section, the pressing surface (64) has a circular arc shape FG or a single or multiple curved shape deviating from a straight line or has a circular arc shape FG that is complementary to the ideal circle line Ki.

21. Straightening tool according to one of the preceding claims 15-20,

d a u r c h u n n n n n n e i c h e te that

the pressing surface has a wedge surface (64) and in particular has a wedge surface (64) formed on a bending projection (68).

22. Straightening tool according to one of the preceding claims 15-21,

d a u r c h u n n n n n n e i c h e te that

the bending means (62) has at least one wedge surface (64) which extends as a rising ramp in the direction of the insertion direction RE.

23. Straightening tool according to one of the preceding claims 15-22,

d a u r c h u n n n n n n e i c h e te that

the bending means (62) is designed such that it the at least one tooth (14,

16) into a bending press fit on both sides.

24. A method for producing and in particular straightening a hole saw, in particular for sawing a circular hole in a plasterboard or similar paper-coated board, in particular according to one of the preceding claims 1 to 14, comprising the following steps:

• Making or using a circular cylindrical main body (2), the

Has: o a saw toothing (12) arranged on a first face end (10) of the main body (2), comprising a plurality of teeth (14, 16), and o an optionally arranged floor element on a second face end (20) of the main body (2) , in particular a base plate (4), can be coupled to a drive means, in particular a drill, for the rotating movement of the hole saw (1);

Deforming the teeth (14, 16) of the saw teeth (12) on the first end face of the main body (2) by means of a straightening tool (30), in particular according to one of claims 15 to 23, and optionally simultaneous straightening of the cross-sectional shape of the main body (2) ) to a circular shape, such that

at least a number of the teeth (14, 16) are bent in such a way, in particular in the radial direction (RR), that they protrude inwards and / or outwards from the outer surface EM of the circular cylindrical main body (2), and the cross section of the circular cylindrical main body (2 ) perpendicular to its axis of rotation AH in the area of the first end face (10) and running along at least one ideal circle line Ki, deviates from an ideal circular shape by a maximum of 0.08% of the diameter, preferably a maximum of 0.05% of the diameter.