US-12617029-B2 - Method for determining a working depth of a tool and tool for machining a workpiece

US12617029B2US 12617029 B2US12617029 B2US 12617029B2US-12617029-B2

Abstract

The invention relates to a method for determining a working depth of a tool. The method includes arranging a tool and a depth determination device on a depth setting device; and applying a predetermined compression force in axial direction to the depth determination device, such that at least a part of the depth determination device is elastically compressed by a certain compression amount against a contact surface, obtaining a compressed state of the depth determination device. The method further includes securing a mounting device to a clamping region of a shaft of the tool in the compressed state of the depth determination device such that the mounting device is firmly mounted to the clamping region, whereby a tool assembly is formed; releasing the compression force from the depth determination device, and removing the tool assembly from the depth setting device.

Inventors

Jochen Kress

Assignees

MAPAL Fabrik für Präzisionswerkzeuge Dr. Kress KG

Dates

Publication Date: 20260505
Application Date: 20211202
Priority Date: 20201204

Claims (20)

1 . Method for determining a working depth of a tool, comprising a) arranging a tool and a depth determination device on a depth setting device in such a way that a mounting device of the depth determination device is located at least partially around a clamping region of a shaft of the tool such that the depth determination device is free to move relative to the tool in an axial direction, and a stop surface of the depth determination device ( 5 ) lies against a contact surface of the depth setting device, and a cutting edge of the tool lies against a limit stop ( 49 ) of the depth setting device; b0) applying a predetermined compression force in axial direction to the depth determination device, such that at least a part of the depth determination device is elastically compressed by a certain compression amount against the contact surface, obtaining a compressed state of the depth determination device; b) securing the mounting device to the clamping region of the shaft in the compressed state of the depth determination device such that the mounting device is firmly mounted to the clamping region of the shaft, whereby a tool assembly is formed; c0) releasing the compression force from the depth determination device, and c) removing the tool assembly from the depth setting device.
2 . The method according to claim 1 , wherein prior to applying the predetermined compression force in step b0), the compression amount by which the depth determination device shall be elastically compressed is defined, and the compression force is set as a function of the defined compression amount.
3 . The method according to claim 1 , wherein the contact surface is provided by the depth setting device in one piece, or by a contact distance element arranged on the depth setting device.
4 . The method according to claim 1 , wherein the limit stop is provided by the depth setting device in one piece, or by a stop distance element arranged on the depth setting device.
5 . The method according to claim 1 , wherein the compression force is at least one of applied by a pressure screw, or pneumatically, or hydraulically; and applied to the mounting device.
6 . The method according to claim 1 , wherein a drilling tool, a milling tool, a chamfering tool, a countersinking tool, a spot facing tool, or a deburring tool is used as the tool.
7 . A tool for machining a workpiece, wherein the tool is adapted to be used in a method according to claim 1 , the tool comprising a tool head having at least one cutting edge, and a shaft, wherein the shaft comprises a clamping region with a friction enhanced surface.
8 . The tool according to claim 7 , wherein the friction enhanced surface comprises a plurality of depressions or a knurled surface.
9 . The tool according to claim 8 , wherein the plurality of depressions includes a plurality of circumferential grooves.
10 . The tool according to claim 7 , wherein the tool head comprises an insertion pin for guiding the tool in a depression of a workpiece to be machined by the tool.
11 . The tool according to claim 7 , wherein the tool is at least one of a drilling tool, a milling tool, a chamfering tool, a countersinking tool, a spot facing tool, and a deburring tool.
12 . The tool according to claim 7 , wherein the tool is adapted to cooperate with a depth determination device.
13 . A depth determination device, comprising a cutting cage adapted to at least partially enclose a tool head of a tool according to claim 7 ; a circumferential bearing device arranged at least partially in the cutting cage and adapted to allow for a relative rotational movement between the cutting cage and the tool, and a mounting device, adapted to be firmly mounted to the tool in a clamping region of the tool, wherein the cutting cage has a stop surface adapted to determine a cutting depth of the tool when the depth determination device is attached to the tool.
14 . The depth determination device according to claim 13 , further comprising an axial bearing device arranged between the cutting cage and the mounting device and adapted to allow for a relative rotational movement between the cutting cage and the mounting device.
15 . The depth determination device according to claim 14 , wherein the circumferential bearing device is a slide bearing, in particular a bearing sleeve, and/or the axial bearing device is a roller bearing, in particular an axial ball bearing, or a slide bearing.
16 . The depth determination device according to claim 13 , wherein the mounting device comprises a clamping ring.
17 . The depth determination device according to claim 13 , wherein the depth determination device has no adjusting device for adjusting an axial distance between the stop surface and a cutting edge of the tool.
18 . The depth determination device according to claim 13 , wherein the cutting cage has a plurality of radial chip openings.
19 . A tool assembly, comprising: a tool configured to be used in the method according to claim 1 , comprising: a tool head having at least one cutting edge, and a shaft, wherein the shaft comprises a clamping region with a friction enhanced surface; and a depth determination device, comprising: a cutting cage adapted to at least partially enclose the tool head, a circumferential bearing device arranged at least partially in the cutting cage and adapted to allow for a relative rotational movement between the cutting cage and the tool, and a mounting device, adapted to be firmly mounted to the tool in a clamping region of the tool, wherein the cutting cage has a stop surface adapted to determine a cutting depth of the tool when the depth determination device is attached to the tool, wherein the mounting device is firmly secured to the clamping region of the tool.
20 . The tool assembly according to claim 19 , wherein the tool assembly is adapted to be coupled to a handheld tool drive.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The application corresponds to PCT/EP2021/084027, filed Dec. 2, 2021, entitled “METHOD FOR DETERMINING A WORKING DEPTH OF A TOOL AND TOOL FOR MACHINING A WORKPIECE”, which claims priority to EP20211983.0, filed Dec. 4, 2020, the entirety of both are incorporated herein by reference. FIELD OF THE INVENTION The invention is related to a method for determining a working depth of a tool, a tool for machining a workpiece, a depth determination device, a tool assembly, and a method for using such tool assembly. A respective tool assembly is known for example from EP 3 033 194 B1. Such a tool assembly is used in particular with a handheld tool drive in order to manually perform a specific operation in a region of a bore, in particular at a skin of an aircraft part, like, e.g., a chamfering, countersinking, spot facing, or deburring operation. Such operation is carried out in order to remove paint from the surface of the respective aircraft part such that a fastener like a bolt or screw may contact the metallic structure beneath the paint and thus be electrically grounded. This type of operation must be accomplished in a reproducible manner and with an axial precision of approximately 10 μm to 20 μm, irrespective of the actual person performing the operation. Therefor the tool assembly has a depth determination device for objectively determining the cutting depth of the tool by providing a stop surface which acts as a limit stop in well-defined axial position relative to a cutting edge of the tool. The tool assembly known from EP 3 033 194 B1 has a relatively complicated structure and therefore is expensive. Further, it needs a cumbersome and elaborate method to determine the working depth of the tool, i.e. to set the relative axial position of the stop surface with respect to the cutting edge. It is therefore an object of the invention to provide a method for determining a working depth of a tool, a tool for machining a workpiece, a depth determination device, a tool assembly, and a method for using such tool assembly, which is relatively cheap and easy to handle, in particular when it becomes necessary to change the tool, e.g. because of wear and tear of the cutting edge. This object is achieved by providing the present technical teachings, in particular the teachings of the independent claims as well as the teachings of the dependent claims and the preferred embodiments disclosed in the description. The object is in particular achieved by providing a method for determining a working depth of a tool, the method comprising a) arranging a tool and a depth determination device on a depth setting device in such a way that a mounting device of the depth determination device is located at least partially around a clamping region of a shaft of the tool such that the depth determination device is free to move relative to the tool in an axial direction, and a stop surface of the depth determination device lies against a contact surface of the depth setting device, and a cutting edge of the tool lies against a limit stop of the depth setting device; b) securing the mounting device to the clamping region of the shaft such that the mounting device is firmly mounted to the clamping region of the shaft, whereby a tool assembly is formed; and c) removing the tool assembly from the depth setting device. Thus, a maximum working depth, which is a maximum cutting depth, of the tool is conveniently determined by an axial distance between the contact surface and the limit stop, because this axial distance determines the axial distance between the stop surface and the cutting edge. The depth setting device serves as a gauge for setting the cutting depth of the tool. By making use of the relatively simple depth setting device having the contact surface and the limit stop the cutting depth of the tool assembly can be set in an easier, faster and cheaper manner than it is the case with known tool assemblies and respective methods. Further, since the cutting depth is precisely and reliably determined by the depth setting device, the depth determination device itself needs not to have any adjusting device for adjusting the axial distance between the stop surface and the cutting edge. Thus, the depth determination device and the tool assembly may be simple in structure and construction as well as inexpensive. Preferably, the mounting device is secured in step b) to the clamping region of the shaft, thereby firmly attaching the mounting device to the clamping region of the shaft such as to prevent any further axial movement of the depth determination device relative to the tool. There may be parts of the depth determination device, however, which preferably are free to axially move relative to the tool between a distal stop, preferably provided by a tool head of the tool, in particular a shoulder of the tool head, or some retaining device like a retaining ring, and a proximal stop, provided by the dept