Drilling aid

Abstract

A device for reaming a hole (21) has a frustoconical base body (1) which can be inserted into a hole (21) of a workpiece (20) and which has an insertion opening (5') for an insertion of a pilot hole drill (19) of a keyhole saw (17). In order to make a useful improvement, the frustoconical outer peripheral surface (2) of the base body (1) has a self-cutting thread which can engage into the wall of the hole (21) to be enlarged. A screwing tool (9) is provided in order to apply a correspondingly large torque.

Description

Technical Field

[0001] The present invention relates to an apparatus for enlarging holes, having a truncated conical base that can be inserted into a hole in a workpiece, the truncated conical base having an insertion opening for inserting a guide hole drill bit for inserting a keyhole saw. Background Technology

[0002] A device of the type described in this invention is known from patent document US 5,871,310 A. Therein is described a device having a frustoconical base. The frustoconical base has rib-like structural portions on its outer circumferential surface, wherein these ribs extend axially / radially. An insertion opening is provided into which a guide hole drill bit of a keyhole saw can be inserted to enlarge the diameter of the hole into which the base is inserted.

[0003] Patent document US 6,409,437 B1 describes a similar device. Patent document DE 2,256,938 A describes a pin for fixing in a plaster wall, wherein the pin has threads on its outer peripheral wall and has a central opening into which a bolt can be screwed. A frustoconical housing insert with external threads is known from patent document DE 2,349,549 A1; the external threads can be connected to a cleaning device. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to improve the device of the type described in the present invention in a manner that is advantageous for use.

[0005] This technical problem is solved by the invention given in the claims. The dependent claims not only represent advantageous extensions of the apparatus given in the independent claims, but are also independent solutions to the said technical problem.

[0006] First and foremost, it is recommended that the truncated conical base has a threaded conical outer circumferential surface. The thread preferably consists of one or more right-hand threaded ribs. Due to the design according to the invention, the base can be first inserted into a hole requiring enlargement, such as a drywall wall, and then screwed in. For this purpose, it proves advantageous that at least one threaded rib has a cross-sectional profile that matches or is at least similar to that of a self-tapping thread, so that the cutting edge formed by the vertex line can cut into the inner wall of the hole to be enlarged. The distance between two adjacent vertex lines is preferably greater than 1 mm, but should be less than 5 mm. Therefore, the pitch can be in the range of 1 mm to 5 mm. The preferred distance between two vertex lines is 2 mm. The pitch can also preferably be 2 mm. The two threaded flanks intersecting in the vertex lines extend in a straight line in the longitudinal cross-section. These two threaded flanks can form an angle at the vertex in the range of 60° to 100°, preferably about 90°. In an extended design of the invention, the insertion opening is provided as a support bushing. The support bushing can be made of metal. The receiving cavity into which the support bushing is inserted can be made of plastic. The receiving cavity can be formed from the same material as the matrix. Furthermore, it can be specified that the matrix is ​​hollow. This hollow body can have an opening pointing towards the bottom surface (or base surface) of the matrix. This opening can be covered by a cover plate. One or more reinforcing ribs can be present in the opening, connecting the inner wall of the matrix to the outer wall of a central sleeve section, into which a support bushing made of hardened metal, particularly hardened steel, is inserted. Advantageously, the support bushing is replaceable. A first support bushing with a first diameter can be pulled axially out of the receiving cavity and replaced with a second support bushing of a different diameter. Therefore, a keyhole saw with different guide hole drill bits can be used. A screw-in opening can be provided, into which bolts for securing the cover plate to the matrix can be screwed. The cover plate can have a fixing opening through which bolts pass. Two fixing openings can be opposite each other relative to the center of the cover plate. The cover plate also has a central opening aligned with the insertion opening. A guide hole drill bit can be inserted through this central opening.

[0007] The invention also relates to a device of the aforementioned type having external threads on the outer circumferential surface of a truncated cone. The device includes a screwing tool having a cutting edge section and an operating section. The cutting edge section can be inserted into at least one engagement slot of the aforementioned device, such as a base, but preferably a cover plate. In particular, two engagement slots are provided, opposite each other to the center of the cover plate, and one end section of each cutting edge section can be inserted into these two engagement slots respectively. The screwing tool can be used to screw the base into the hole to be enlarged, so as to apply a correspondingly large torque to the base. The cover plate and the screwing tool can be made of metal, especially steel.

[0008] The tightening tool can be a flat piece. Furthermore, inspection openings can be incorporated into the tightening tool. These inspection openings can have circular cross-sections of varying diameters. Attached Figure Description

[0009] The invention is described below with reference to the accompanying drawings. In the drawings:

[0010] Figure 1 A perspective view of a device in the form of a drilling aid for reaming according to the present invention is shown;

[0011] Figure 2 Showing with Figure 1 The illustration matches, but tool 9 has been removed;

[0012] Figure 3 A top view of device 1 is shown;

[0013] Figure 4 Showing according to Figure 3 A cross-sectional view of line IV-IV in the middle;

[0014] Figure 5 An exploded view of device 1 is shown;

[0015] Figure 6 A diagram is shown illustrating the common use of the device 1 and the workpiece 20 having the hole 21 before inserting the device 1 into the hole 21 to be enlarged;

[0016] Figure 7 Show Figure 6 The following figure shows that the device 1 has been inserted into the hole 21 to be enlarged, wherein the external thread 15 of the device 1 is cut into the wall of the hole 21 by means of a screwing tool 9;

[0017] Figure 8 Showing according to Figure 7 The cross-sectional view of line VIII-VIII in the middle shows the pitch 15 cut into the wall of hole 21;

[0018] Figure 9 Enlarged Figure 8 The following figure shows that the guide hole drill bit 19 of the keyhole saw 17 is inserted into the insertion opening 5' of the device 1, and the saw body 18 of the keyhole saw has a diameter larger than the maximum diameter of the device 1.

[0019] Figure 10 Show Figure 9 The following figure shows that, by means of a drilling machine acting on the handle 19', the saw body 18 has been placed in rotation and its teeth have been used to make a second hole 21' with an enlarged diameter. Detailed Implementation

[0020] The device shown in the figure consists of a screw-in body and a screw-in tool. The screw-in body has a frustoconical base 1 made of plastic. The frustoconical base 1 has a frustoconical outer peripheral surface 2, on which one or more threaded ribs 15 are located. It is sufficient for the presence of one threaded rib 15 on the frustoconical outer peripheral surface 2, extending helically from the bottom edge to the top edge of the base. The threaded rib 15 may have a self-tapping thread cross-sectional profile. The threaded rib 15 preferably has a vertex line 15', on which two threaded facets 15' are respectively connected. The two threaded facets 15' intersect in the valley of the line. The pitch is selected such that the vertex line 15' can be engraved into the sidewall of the hole 21 to be enlarged in the workpiece 20. The torque required for this can be applied by the screw-in tool to screw the base into the hole to be enlarged in a bolt-like manner. The threaded facets 15' intersect the vertex line 15' at an angle that may be approximately 90° or in the range of 80° to 100°.

[0021] Figure 1 and Figure 2 As shown, the thread ribs do not continuously surround the truncated cone-shaped base 1. Instead, the external thread is interrupted by a flat portion 22 in the circumferential section. The pitch terminating at this point constitutes a cutting edge that is etched into the wall as the external thread is screwed into the wall of the hole 21 to be enlarged.

[0022] The base 1 is a hollow body. The base is open towards its bottom. The opening forms five sub-openings. Four cavity sections, each adjacent to the outer wall of the base 1, are circumferentially adjacent to each other and separated by reinforcing ribs 16. The reinforcing ribs 16 connect the outer wall of the base 1 to the inner sleeve sections. The sleeve sections have a central opening forming a receiving cavity 6 into which a hardened drill bushing or support bushing 5 is inserted. The support bushing 5 has an insertion opening 5' into which the guide drill bit 19 of the keyhole saw 17 can be inserted.

[0023] Support bushing 5 can be replaced with other support bushings with different diameters, so that pilot hole drill bits with different diameters can be used.

[0024] The open side of the base 1 is covered by a cover plate 3. The cover plate 3 is made of steel and has two fixing openings 4 that are opposite each other relative to the center. Fixing bolts 8, which are screwed into the screw-in openings 7 of the base 1, pass through these fixing openings 4. The screw-in openings 7 are located in the area of ​​the reinforcing rib 16.

[0025] The cover plate 4 has a central opening 13, the edge of which is interrupted by two oppositely oriented interlocking slots 14. The interlocking slots 14 open toward the edge and are aligned with each other.

[0026] A turning tool 9 is provided, which is made of steel plate and forms an operating section 12 and a cutting edge section 11. The operating section 12 can be gripped by the fingers of a human hand. The cutting edge section 11 can be inserted into the engagement gap 14. By applying torque to the turning tool 9, the substrate 1 inserted into the hole 21 to be enlarged can be fixed in the hole 21 such that the vertex line 15' is engraved into the wall of the hole 21.

[0027] The insertion opening 5' is preferably located on the axis of symmetry of the base 1. The guide drill bit 19 of the keyhole saw 17 can be inserted into the insertion opening 5'. The diameter of the saw body 18, which has serrations at its lower edge, is larger than the outer diameter of the base 1, so that the base 1 can be completely covered by the bell-shaped saw body 18 of the keyhole saw 17. The keyhole saw 17 is used to drill a core from the workpiece 20, which contains a hole 21 to be enlarged, the hole having the base 1 inserted therein.

[0028] The base 1 can be unscrewed from the hole 21 using the screw-on tool 9. The handle section of the screw-on tool 9 also has multiple diameter inspection openings 10, 10', 10" for checking the diameter of the drill bit.

[0029] The foregoing embodiments are used to illustrate the invention as generally included in this application, which extends the prior art through at least the following combinations of features, each of which independently extends the prior art. Two, more, or all of these combinations of features may also be combined with each other, namely:

[0030] An apparatus characterized in that the outer peripheral surface 2 of the truncated cone of the base 1 has threads.

[0031] An apparatus characterized in that the thread has at least one thread rib 15 having substantially flat threaded sides 15" intersecting in vertex lines 15', and / or the thread is a self-tapping thread.

[0032] An apparatus characterized in that the distance between two adjacent vertex lines 15' is greater than 1 mm and particularly less than 5 mm, and / or the pitch of the thread is between 1 mm and 5 mm.

[0033] An apparatus characterized in that the insertion opening 5' is formed by a support bushing 5, which is particularly replaceable in a receiving cavity 6 of a base 1, and / or the insertion opening 5' extends at the geometric center of the base 1.

[0034] An apparatus characterized in that the substrate 1 is made of plastic or metal, such as steel, and / or the substrate is a hollow body, which is particularly open at its end side having a larger diameter.

[0035] An apparatus characterized in that the opening of a hollow substrate 1 is covered by a cover plate 3 having a central opening 13, the central opening being arranged co-centered with respect to an insertion opening 5' and / or the cover plate being made of plastic or metal, such as steel.

[0036] An apparatus characterized by a screwing tool 9 having a blade section 11, wherein an insertion opening 14 for inserting the blade section is provided in a base 1 or a cover plate 3, and / or the central opening 13 of the cover plate 3 has two opposing meshing slots 14.

[0037] An apparatus characterized in that the diameter inspection openings 10, 10', 10" are in the handle region of the screwing tool 9.

[0038] An apparatus characterized in that the cone angle α of the envelope cone is in the range of 30° to 50°, and / or the diameter of the base is approximately 1.5 to 2 times the axial length of the base.

[0039] All disclosed features (either individually or in different combinations) are essential to the invention. Therefore, the disclosure of this application also includes the full content of the relevant / attached priority documents (copies of earlier applications), and for this purpose, the features of the priority documents are also incorporated into the claims of this application. Dependent claims, by virtue of their features, characterize unique inventive improvements of the prior art even when they do not possess the features of the cited claims, and are particularly useful for divisional applications based on such features. The invention described in each claim may additionally include one or more features described in the preceding description, particularly with reference numerals and / or in the list of reference numerals. The invention also relates to various design embodiments in which the individual features mentioned above are not implemented, especially when they are considered irrelevant to the corresponding purpose of use or can be replaced by other means that achieve the same effect.

[0040] List of reference numerals

[0041] 1. Frustum-shaped matrix

[0042] 2. Outer circumference of the truncated cone

[0043] 3. Cover plate

[0044] 4. Fixed opening

[0045] 5 Support bushing

[0046] 5' Insertion opening

[0047] 6. Accommodating cavity

[0048] 7. Screw into the opening

[0049] 8 bolts

[0050] 9. Tightening tools

[0051] 10 Diameter Inspection Opening

[0052] 10' Diameter Inspection Opening

[0053] 10" diameter inspection opening

[0054] 11. Blade Section

[0055] 12 Operating Sections

[0056] 13. Central opening

[0057] 14. Meshing gap

[0058] 15 Threaded Ribs

[0059] 15' Vertex Line

[0060] 15" threaded side

[0061] 16 Reinforcing Ribs

[0062] 17 Keyhole Saw

[0063] 18. Saw body

[0064] 19. Pilot hole drill bit

[0065] 19' Handle

[0066] 20 workpieces

[0067] 21 holes

[0068] 21' enlarged aperture

[0069] 22 Flat area

[0070] α cone angle

Claims

1. An apparatus for enlarging a hole (21) having a truncated cone-shaped base (1) capable of being inserted into a hole (21) of a workpiece (20), the truncated cone-shaped base having an insertion opening (5') for inserting a guide hole drill bit (19) of a keyhole saw (17), characterized in that, The outer peripheral surface (2) of the truncated cone of the base (1) has a thread, the thread having at least one thread rib (15) having a flat thread side (15") intersecting in the vertex line (15'), or the thread is a self-tapping thread, the truncated cone base is a hollow body, wherein the truncated cone base is made of plastic, wherein the truncated cone base has an outer wall and an inner sleeve section, wherein the truncated cone base has at least one reinforcing rib that connects the outer wall to the inner sleeve section.

2. The apparatus according to claim 1, characterized in that, The distance between two adjacent vertex lines (15') is greater than 1 mm and less than 5 mm, or the pitch of the thread is between 1 mm and 5 mm.

3. The apparatus according to claim 1, characterized in that, The insertion opening (5') is formed by a support bushing (5) which can be alternatively arranged in the receiving cavity (6) of the base (1), and / or the insertion opening (5') extends at the geometric center of the base (1).

4. The apparatus according to claim 1, characterized in that, The insertion opening (5') of the hollow substrate (1) is covered by a cover plate (3) having a central opening (13) arranged cocentrically relative to the insertion opening (5') and / or the cover plate is made of plastic or metal.

5. The apparatus according to claim 4, characterized in that... A screwing tool (9) having a blade section (11) wherein a meshing slot (14) for inserting the blade section is provided in the base (1) or cover plate (3), and / or the central opening (13) of the cover plate (3) has two opposing meshing slots (14).

6. The apparatus according to claim 5, characterized in that, The handle area of ​​the screwing tool (9) has diameter inspection openings (10, 10', 10").

7. The apparatus according to claim 1 or 2, characterized in that, The cone angle (α) of the envelope cone of the truncated cone matrix (1) is in the range of 30° to 50°, and / or the diameter of the base of the matrix is ​​equal to 1.5 to 2 times the axial length of the matrix.

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