Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/003—Stops for limiting depth in rotary hand tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B49/00—Measuring or gauging equipment on boring machines for positioning or guiding the drill; Devices for indicating failure of drills during boring; Centering devices for holes to be bored
  • B23B49/003—Stops attached to drilling tools, tool holders or drilling machines
  • B23B49/006—Attached to drilling machines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25H—WORKSHOP EQUIPMENT, e.g. FOR MARKING-OUT WORK; STORAGE MEANS FOR WORKSHOPS
  • B25H1/00—Work benches; Portable stands or supports for positioning portable tools or work to be operated on thereby
  • B25H1/0021—Stands, supports or guiding devices for positioning portable tools or for securing them to the work
  • B25H1/0078—Guiding devices for hand tools
  • B25H1/0092—Guiding devices for hand tools by optical means
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/22—Measuring arrangements characterised by the use of optical techniques for measuring depth
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C3/00—Measuring distances in line of sight; Optical rangefinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2260/00—Details of constructional elements
  • B23B2260/092—Lasers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2270/00—Details of turning, boring or drilling machines, processes or tools not otherwise provided for
  • B23B2270/32—Use of electronics

Definitions

• the invention is based on a method for measuring the distance of a hand tool from a workpiece to be machined according to the preamble of the main claim.
• a drilling machine is known in which a profile rod made of plastic or metal is provided parallel to the tool axis for distance measurement or borehole depth measurement.
• the profile bar is arranged in a holder fastened to the drilling machine so as to be displaceable in the tool axis.
• the profile bar can be locked by tightening a wing screw. It is clamped so that it protrudes forward so that the front tip of the rod strikes the workpiece when the set drill hole depth is reached.
• a disadvantage of this measuring method is that the protrusion of the rod and thus the predeterminable borehole depth can only be set with little precision by eye. It can happen that an unintentional longitudinal displacement of the Rod occurs while locking the wing screw. Unintended drilling of the workpiece cannot be ruled out in all cases.
• the method according to the invention has the advantage that the distance measurement is carried out with high measuring accuracy.
• the triangulation method known per se is provided.
• a radiation source projects an optical pattern onto the surface of the workpiece and the radiation reflected from the surface is imaged on a radiation receiver.
• the position of the optical pattern imaged on the radiation receiver represents a measure of the distance of the workpiece from the hand machine tool.
• the distance information is further processed in a signal processing arrangement which has an input device and an optical and acoustic output device. If the hand tool is a drill, the depth of the borehole is determined.
• a setpoint value for the depth of the borehole is entered into the signal processing arrangement via the input device and the depth of the borehole reached is continuously displayed on the display device of the signal processing arrangement during the drilling process.
• the display is expediently set to zero at the start of drilling. Without this zero setting, differential measurements are also possible. It is a great advantage if the acoustic output unit of the signal processing arrangement emits an acoustic signal before the setpoint value is reached. In this way, it is possible to reduce the feed force exerted on the handheld power tool in good time before reaching the setpoint in order to counteract an unintentional exceeding of the setpoint.
• the target value can also be approximated, for example, by flashing and changing the color of the display.
• An advantage that is particularly noticeable in battery-operated devices results from the pulsed operation of the radiation source. With pulsed operation, a high radiation output is achieved with a lower average energy.
• the figure shows an optoelectronic circuit arrangement and the optical radiation path between a hand machine tool and an object to be processed.
• the figure shows a radiation source 10 which is controlled by a pulse generator 11.
• the radiation source 10 is arranged in the focal point of a first lens 12.
• a diaphragm 13 Immediately adjacent to the first lens 12 is a diaphragm 13.
• the radiation source 10, the pulse generator 11, the first lens 12 and the diaphragm 13 are within one hand
• Machine tool 14 is arranged, which has an area 15 in its housing, which is transparent to the radiation emitted by the radiation source 10.
• the area 15 is shown with a broken line.
• a surface 17 of a workpiece 18 is located at a first distance 16 from the machine tool 14. During the machining process, the first distance 16 changes to a second distance 19.
• the marginal rays 20 delimit an irradiated part 22 of the surface 17 of the workpiece 18.
• the radiation 26 reflected by the irradiated surface part 22 is imaged into an image area 25 with a second lens 24.
• the surface 22 located at the first distance 1 ⁇ from the hand-held power tool 14 is assigned a first image 27 and the surface 22 located at the second distance 19 is assigned a second image 28 in the image surface 25.
• the image area 25 coincides with an active surface 29 of a radiation receiver 30.
• An output signal 31 from the radiation receiver 30 arrives in a signal processing arrangement 32 which has an input device 33, an optical output device 34 and an acoustic output device 35.
• the signal processing arrangement 32 is connected to a control circuit 36 of a drive motor 37 via two control lines 38, 39.
• the switch 40 is the on-off switch of the hand machine tool.
• the distance measurement procedure works as follows:
• the radiation emanating from the radiation source 10 is directed onto the workpiece 18 with the first lens 12. If the radiation source 10 is located in the focal point of the first lens 12, which is designed as a converging lens, a parallel radiation is produced which is delimited by edge rays 20 bundle of the emitted radiation 21. With the diaphragm 13 arranged directly next to the first lens 12, certain radiation components can be masked out in order to produce a certain optical pattern on the surface 17 of the workpiece 18. The emitted radiation 21 strikes a part 22 of the surface 17 and is diffusely scattered there.
• the second lens 24, which is also designed as a converging lens, receives a part of the reflected radiation 26 and images the surface part 22 into the image area 25. A flat pattern of the radiation signal generated with the aperture 13 appears as an image in the image area 25 of the second lens 24.
• the optical arrangement is fastened in or on the hand power tool 14, the distance 16, 19 of which from the surface 17 of the workpiece 18 is to be determined.
• the position of the image 27, 28 of the surface 22 in the image area 25 is a clear function of this distance.
• the given first distance 16 is mapped to the first image 27 and the second distance 19 to the second image 28.
• This described method for measuring a certain distance is known per se as a triangulation method in measurement technology (VDI-Zeitung 125, 1983 , No. 21, p. 876).
• VDI-Zeitung 125, 1983 , No. 21, p. 876 a continuous determination of the change in distance during a machining process using the triangulation method has so far not become known.
• the radiation receiver 30 is provided, the active surface 29 of which should match the image surface 25 as closely as possible. The more precisely this requirement is met, the more precise the position information of the two images 27, 28 is.
• the radiation receiver 30 is, for example, a position-sensitive one Photodiode or a multisensor in the form of a photodiode or CCD line.
• the output signal 31 of the sensor 30 arrives in the signal processing arrangement 32. Conversions are carried out in this arrangement. For example, a hole depth reached is determined from a change in distance. If the position of the first image 27 moves in the direction of the position of the second image 28 during the machining process, then the change in distance or the borehole depth is determined continuously from the position difference and displayed on the optical output device 34.
• the signal-processing arrangement 32 is given a set-point depth value.
• a reset signal for zeroing the display 35 is input via the input device 33.
• a signal which can be emitted by the control circuit 36 via the control line 39 as a function of the actuation of the switch 40 of the handheld power tool 14 for zeroing.
• the depth of the borehole reached is continuously displayed during the drilling process.
• the threshold value lying in front of the target value, from which this warning is to be given, can be input via the input device 33.
• the signal processing arrangement 32 triggers an acoustic signal via the acoustic output device 34.
• the approximation to the target value can be indicated by the flashing of the display 35. Leave that optical output device 35 to different color information, the reaching of the threshold value can also be signaled by a color change.
• the advantage of warning the user before the setpoint is reached is that the feed force can be reduced in good time so that a possible overrun of the electric motor 37 after it has been switched off does not result in the workpiece 18 being drilled unintentionally.
• the signal processing arrangement 32 supplies the control circuit 36 with a signal for switching off the drive motor 27 and triggers an acoustic signal.
• a pulse power that is above the permissible continuous power can be emitted in the pulsed mode.
• a high pulse power results in a high signal-to-noise ratio and therefore reduces the outlay on equipment for the optoelectronic arrangement. If the pulse-pause ratio is set appropriately, the average energy required is reduced - an advantage that is particularly noticeable in battery-operated devices.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Electromagnetism (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
• Length Measuring Devices With Unspecified Measuring Means (AREA)
• Measurement Of Optical Distance (AREA)
• Machine Tool Sensing Apparatuses (AREA)
• Drilling And Boring (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6300612

Family Applications (1)

Country Status (4)

Cited By (2)

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• 1986
  • 1986-05-10 DE DE19863615874 patent/DE3615874A1/de not_active Withdrawn
• 1987
  • 1987-04-11 EP EP19870902391 patent/EP0308403A1/de not_active Ceased
  • 1987-04-11 JP JP62502433A patent/JPH01502412A/ja active Pending
  • 1987-04-11 WO PCT/DE1987/000165 patent/WO1987007011A1/de not_active Ceased

Non-Patent Citations (1)

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