CA3048079A1 - Improved bit holder for grinding apparatus - Google Patents
Improved bit holder for grinding apparatus Download PDFInfo
- Publication number
- CA3048079A1 CA3048079A1 CA3048079A CA3048079A CA3048079A1 CA 3048079 A1 CA3048079 A1 CA 3048079A1 CA 3048079 A CA3048079 A CA 3048079A CA 3048079 A CA3048079 A CA 3048079A CA 3048079 A1 CA3048079 A1 CA 3048079A1
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- CA
- Canada
- Prior art keywords
- grinding
- ground
- grinding machine
- bit
- rock drill
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
- B24B3/24—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills
- B24B3/33—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills of drills for stone
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B41/00—Component parts such as frames, beds, carriages, headstocks
- B24B41/06—Work supports, e.g. adjustable steadies
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
Abstract
A grinding apparatus for grinding the hard metal inserts of rock drill bits, said grinding apparatus having a grinding machine carried on an support system and means for holding one or more bits to be ground, said grinding machine equipped with a grinding cup driven by a motor to rotate about its longitudinal axis, wherein the support system comprises an arm or lever system to control movement of the grinding machine for alignment of the grinding machine with a hard metal insert to be ground, means to provide grinding pressure, means to monitor and control one or more operational functions of the grinding apparatus selected from the group consisting of force, grinding pressure, movement and speed of movement of the grinding machine during alignment with a hard metal insert wherein the means for holding one or more rock drill bits to be ground has one or more apertures to hold one or more rock drill bits to be ground includes a moveable floor plate for each aperature to support a free end of a shank on the bit to be held in the aperature
Description
TITLE: IMPROVED BIT HOLDER FOR GRINDING APPARATUS
BACKGROUND
The present disclosure relates to improvements in apparatus for grinding the hard metal inserts or working tips of rock drill bits (percussive or rotary), tunnel boring machine cutters (TBM) and raised bore machine cutters (REM) and more specifically, but not exclusively, for grinding the cutting teeth or buttons of a rock drill bit or cutter.
In drilling operations the cutting teeth (buttons) on the drill bits or cutters become flattened (worn) after continued use. Regular maintenance of the drill bit or cutter by regrinding (sharpening) the buttons to restore them to substantially their original profile enhances the bit/cutter life, speeds up drilling and reduces drilling costs. Regrinding should be undertaken when the wear of the buttons is optimally one third to a maximum of one-half the button diameter.
Manufacturers have developed a range of different manual and semi-automatic grinding machines including hand held grinders, single arm and double arm self centering grinding machines and grinders designed specifically for mounting on drill rigs, service vehicles or set up in the shop.
These types of machines utilize a grinding machine having a spindle or rotor rotated at high speed. A grinding cup or grinding pin, mounted on the end of the rotor or spindle, grinds the button and typically the face of the bit/cutter surrounding the base of the button to restore the button to substantially its original profile for effective drilling. In addition to the rotation of the grinding cup, these types of grinding machines may include
BACKGROUND
The present disclosure relates to improvements in apparatus for grinding the hard metal inserts or working tips of rock drill bits (percussive or rotary), tunnel boring machine cutters (TBM) and raised bore machine cutters (REM) and more specifically, but not exclusively, for grinding the cutting teeth or buttons of a rock drill bit or cutter.
In drilling operations the cutting teeth (buttons) on the drill bits or cutters become flattened (worn) after continued use. Regular maintenance of the drill bit or cutter by regrinding (sharpening) the buttons to restore them to substantially their original profile enhances the bit/cutter life, speeds up drilling and reduces drilling costs. Regrinding should be undertaken when the wear of the buttons is optimally one third to a maximum of one-half the button diameter.
Manufacturers have developed a range of different manual and semi-automatic grinding machines including hand held grinders, single arm and double arm self centering grinding machines and grinders designed specifically for mounting on drill rigs, service vehicles or set up in the shop.
These types of machines utilize a grinding machine having a spindle or rotor rotated at high speed. A grinding cup or grinding pin, mounted on the end of the rotor or spindle, grinds the button and typically the face of the bit/cutter surrounding the base of the button to restore the button to substantially its original profile for effective drilling. In addition to the rotation of the grinding cup, these types of grinding machines may include
2 features where the grinding machine is mounted at an angle to the longitudinal axis of the button and the grinding machine is rotated to provide orbital motion with the center of rotation lying in the center of the grinding cup.
When grinding the buttons, the centering aspects of the grinding machine tend to center the grinding machine over the highest point on the button.
Longstanding problems with these types of grinding machines are vibration and noise due to high rotational speeds, wear, the requirement for large compressors for pneumatic systems and long grinding times per button, in the larger sizes.
U.S. Patent No. 7,402,093 addressed a number of problems with earlier machines and provided a grinding machine carried on a support system where the grinding cup is rotated at variable speeds preferably from about 2200 to 6000 RPM and the support system is capable of providing a variable feed pressure preferably or optionally up to 350 kilos. In this type of machine there is a need to provide better support for larger bits during grinding.
SUMMARY OF THE INVENTION
Accordingly the present disclosure provides embodiments of a grinding apparatus for grinding the hard metal inserts of rock drill bits. The grinding apparatus has a grinding machine carried on a support system and means for holding one or more bits to be ground. The grinding machine is equipped with a grinding cup driven by a motor to rotate about its longitudinal axis. An aspect of the present disclosure relates to embodiments of grinding apparatus wherein means for holding one or more rock drill bits to be ground are provided that include a moveable
When grinding the buttons, the centering aspects of the grinding machine tend to center the grinding machine over the highest point on the button.
Longstanding problems with these types of grinding machines are vibration and noise due to high rotational speeds, wear, the requirement for large compressors for pneumatic systems and long grinding times per button, in the larger sizes.
U.S. Patent No. 7,402,093 addressed a number of problems with earlier machines and provided a grinding machine carried on a support system where the grinding cup is rotated at variable speeds preferably from about 2200 to 6000 RPM and the support system is capable of providing a variable feed pressure preferably or optionally up to 350 kilos. In this type of machine there is a need to provide better support for larger bits during grinding.
SUMMARY OF THE INVENTION
Accordingly the present disclosure provides embodiments of a grinding apparatus for grinding the hard metal inserts of rock drill bits. The grinding apparatus has a grinding machine carried on a support system and means for holding one or more bits to be ground. The grinding machine is equipped with a grinding cup driven by a motor to rotate about its longitudinal axis. An aspect of the present disclosure relates to embodiments of grinding apparatus wherein means for holding one or more rock drill bits to be ground are provided that include a moveable
3 floor plate for each aperature and movement of said floor plate is controlled by a linear actuator.
Further features of the invention will be described or will become apparent in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the disclosure may be more clearly understood, the embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:
FIGURE 1 is perspective view from the right side of one embodiment of a grinding apparatus having a grinding machine carried for vertical and horizontal adjustment by a support system, and means for holding the bit(s) to be ground and with a schematic illustration of a large down the hole bit (the bit illustration does not show the hard metal inserts or buttons to be ground).
FIGURE 2 is left side view the grinding apparatus of FIGURE
1 with shielding removed around the bit.
FIGURE 3 is a top perspective view of one embodiment of bit holder for the grinding apparatus of FIGURE 1.
FIGURE 4 is a bottom view of the bit holder of Figure 3 with the aperature closed.
FIGURE 5 is a bottom view of the bit holder of Figure 3 with the aperature open.
Further features of the invention will be described or will become apparent in the course of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the disclosure may be more clearly understood, the embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:
FIGURE 1 is perspective view from the right side of one embodiment of a grinding apparatus having a grinding machine carried for vertical and horizontal adjustment by a support system, and means for holding the bit(s) to be ground and with a schematic illustration of a large down the hole bit (the bit illustration does not show the hard metal inserts or buttons to be ground).
FIGURE 2 is left side view the grinding apparatus of FIGURE
1 with shielding removed around the bit.
FIGURE 3 is a top perspective view of one embodiment of bit holder for the grinding apparatus of FIGURE 1.
FIGURE 4 is a bottom view of the bit holder of Figure 3 with the aperature closed.
FIGURE 5 is a bottom view of the bit holder of Figure 3 with the aperature open.
4 FIGURE 6 is a top view of one embodiment of bit holder with shelding removed according to the present invention.
FIGURE 7 is a front view of the bit holder of FIGURE 6.
FIGURE 8 is a rear bottom view of the bit holder of FIGURE
6.
FIGURE 9 an enlarged bottom view of the bit holder similar to the one illustrated in FIGURE 6 with the motor for the linear actuator arranged differently.
FIGURE 10 is an enlarged view of the motor for the linear actuator of FIGURE 9.
DETAILED DESCRIPTION
With reference to the FIGURES 1 to 5 one embodiment of a grinding apparatus is generally indicated at 1. The grinding apparatus 1 includes a grinding machine 2, means for holding one or more bits to be ground generally indicated at 3 and a support system generally indicated at 4. The grinding machine 2, means for holding the bits 3 and support system 4 are arranged to permit relative movement between the grinding machine 2 and the bit to be ground to permit alignment of the grinding machine 2 with the longitudinal axis of the buttons on the bit. The grinding apparatus 1 has a control system, part of which is generally indicated at 5, having a programmable operator control panel 35 capable of directly or indirectly monitoring and adjusting one or more operational parameters. The operational parameters may include feed =
pressure, grinding cup RPM, grinding time and other parameters as noted herein.
In the embodiment of the grinding apparatus 1 shown in Figures 1-5, the grinding machine 2 is carried by support system 4 which includes an arm or lever system 6 journaled on a stand 7 attached to the rear 8 of an open box 9. The bit holder means 3 consists of a table 10 mounted within the box 9.
In the embodiment shown, the arm or lever system 6 for carrying and positioning the grinding machine 2 as noted previously is journaled onto a stand 7 at the rear 8 of the box 9. The arm system 6 consists of a first arm section 11 having one end 12 journaled to the stand 7. The other end 13 of the first arm section 11 is journaled to the backside 14 of a first control box 15. The first arm section 11, in this embodiment, controls the horizontal location of the grinding machine 2 relative to the bit to be reground. To the front side 16 of the first control box is pivotally mounted a second arm section 17. The second arm section 17 consists of a pair of parallel arms 18,19 with one end 20,21 of each arm 18,19 pivotally mounted to the front side 16 of the first control box 15. The other end 22,23 of each arm 18,19 is pivotally connected to the backside 24 of a second control box 25. The second arm section 17 controls the vertical movement of the grinding machine 2 up and down.
In the embodiment illustrated in FIGURES 3-5, the means for holding the bits 3 is a table 10 mounted within the box 9 at pivot points on each side of the box 9 to permit the table 10 to be tilted. In FIGURE 4 a linear actuator 60 is shown as controlling the tilting action of table 10. The bit holder means 3, in this case table 10, may be provided with one or more apertures 50 to hold one or more bits to be ground. In the embodiment illustrated table 10 has one aperture 50. When a bit(s) is positioned in an aperture 50 the shank of the bit is placed against the front edges 51,52 of aperture 50. The front edges 51,52 may be rubber coated. The bit is held in place against front edges 51,52 by pressure plate 53 controlled by a second linear actuator 54 and lever arm assembly 55. Means are provided to monitor and control the travel of the linear actuator. In the embodiment illustrated the linear actuator 54 is an electro mechanical actuator. By monitoring the amperage used by the electric motor for the actuator 54, when the amperage spikes the control system 5 can stop the electric motor from advancing the actuator further. The amperage will spike when the pressure plate 53 contacts the shank of the bit when the shank is contacting front edges 51,52 of aperature 50. A shield 56 is attached to and moves with the pressure plate 53 and fully covers the opening between the rear 57 of pressure plate 53 and back 58 of the aperture 50. The shield 56 prevents accidental pinching of fingers, etc. when the pressure plate 53 is retracted. The linear actuator 54 can be backed off slightly to rotate the bit (to the next button to be ground) within the aperture 50 without full retraction of the linear actuator 54 and pressure plate 53. The controls for operating the linear actuator 54 may be provided on the sides of box 9. While the method of holding a bit in the bit holder means is shown as a pressure plate 53 and linear actuator 54 other arrangements are possible and the present invention is not limited to the embodiment is illustrated.
FIGURES 6-10 illustate one embodiment of an improvement to the bit holder shown in FIGURES 3-5. In FIGURES 6-9 a moveable floor plate is illustrated on which the free end of a drill bit can rest. The floor plate is moveable to accommodate different sizes of drill bits having longer or shorter stems. The floor plate positioning is controller by a linerar actuator. In the embodiments illustrated the linear actuator is an electro-mechanical actuator having a threaded rod as best shown in FIGURE 10 that is rotated using a gear assembly powered by an electric motor. The moveable floor plate is mounted on a bracket moveable up and/or down on vertical support member.
The threaded rod extends through a threaded block on the bracket. As the threaded rod is rotated the bracket moves up or down.
On advantage of the moveable floor plate of the present invention is that after a button has been ground the pressure plate holding the bit in position is backed off slightly so that the bit can be rotated to position the next button to be ground. The moveable floor plate supports the bit without assistance from the operator.
Another advantage is that the floor plate can be moved up or down so the bit is supported by pressure plate near the working surface of the bit rather than down the shank of the bit. This provides better support during grinding.
Having illustrated and described a preferred embodiment of the invention and certain possible modifications thereto, it should be apparent to those of ordinary skill in the art that the invention permits of further modification in arrangement and detail and is not restricted to the specific semi-automatic grinding apparatus illustrated.
It will be appreciated that the above description related to the preferred embodiment by way of example only.
Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within the scope of the invention as described and claimed, whether or not expressly described.
FIGURE 7 is a front view of the bit holder of FIGURE 6.
FIGURE 8 is a rear bottom view of the bit holder of FIGURE
6.
FIGURE 9 an enlarged bottom view of the bit holder similar to the one illustrated in FIGURE 6 with the motor for the linear actuator arranged differently.
FIGURE 10 is an enlarged view of the motor for the linear actuator of FIGURE 9.
DETAILED DESCRIPTION
With reference to the FIGURES 1 to 5 one embodiment of a grinding apparatus is generally indicated at 1. The grinding apparatus 1 includes a grinding machine 2, means for holding one or more bits to be ground generally indicated at 3 and a support system generally indicated at 4. The grinding machine 2, means for holding the bits 3 and support system 4 are arranged to permit relative movement between the grinding machine 2 and the bit to be ground to permit alignment of the grinding machine 2 with the longitudinal axis of the buttons on the bit. The grinding apparatus 1 has a control system, part of which is generally indicated at 5, having a programmable operator control panel 35 capable of directly or indirectly monitoring and adjusting one or more operational parameters. The operational parameters may include feed =
pressure, grinding cup RPM, grinding time and other parameters as noted herein.
In the embodiment of the grinding apparatus 1 shown in Figures 1-5, the grinding machine 2 is carried by support system 4 which includes an arm or lever system 6 journaled on a stand 7 attached to the rear 8 of an open box 9. The bit holder means 3 consists of a table 10 mounted within the box 9.
In the embodiment shown, the arm or lever system 6 for carrying and positioning the grinding machine 2 as noted previously is journaled onto a stand 7 at the rear 8 of the box 9. The arm system 6 consists of a first arm section 11 having one end 12 journaled to the stand 7. The other end 13 of the first arm section 11 is journaled to the backside 14 of a first control box 15. The first arm section 11, in this embodiment, controls the horizontal location of the grinding machine 2 relative to the bit to be reground. To the front side 16 of the first control box is pivotally mounted a second arm section 17. The second arm section 17 consists of a pair of parallel arms 18,19 with one end 20,21 of each arm 18,19 pivotally mounted to the front side 16 of the first control box 15. The other end 22,23 of each arm 18,19 is pivotally connected to the backside 24 of a second control box 25. The second arm section 17 controls the vertical movement of the grinding machine 2 up and down.
In the embodiment illustrated in FIGURES 3-5, the means for holding the bits 3 is a table 10 mounted within the box 9 at pivot points on each side of the box 9 to permit the table 10 to be tilted. In FIGURE 4 a linear actuator 60 is shown as controlling the tilting action of table 10. The bit holder means 3, in this case table 10, may be provided with one or more apertures 50 to hold one or more bits to be ground. In the embodiment illustrated table 10 has one aperture 50. When a bit(s) is positioned in an aperture 50 the shank of the bit is placed against the front edges 51,52 of aperture 50. The front edges 51,52 may be rubber coated. The bit is held in place against front edges 51,52 by pressure plate 53 controlled by a second linear actuator 54 and lever arm assembly 55. Means are provided to monitor and control the travel of the linear actuator. In the embodiment illustrated the linear actuator 54 is an electro mechanical actuator. By monitoring the amperage used by the electric motor for the actuator 54, when the amperage spikes the control system 5 can stop the electric motor from advancing the actuator further. The amperage will spike when the pressure plate 53 contacts the shank of the bit when the shank is contacting front edges 51,52 of aperature 50. A shield 56 is attached to and moves with the pressure plate 53 and fully covers the opening between the rear 57 of pressure plate 53 and back 58 of the aperture 50. The shield 56 prevents accidental pinching of fingers, etc. when the pressure plate 53 is retracted. The linear actuator 54 can be backed off slightly to rotate the bit (to the next button to be ground) within the aperture 50 without full retraction of the linear actuator 54 and pressure plate 53. The controls for operating the linear actuator 54 may be provided on the sides of box 9. While the method of holding a bit in the bit holder means is shown as a pressure plate 53 and linear actuator 54 other arrangements are possible and the present invention is not limited to the embodiment is illustrated.
FIGURES 6-10 illustate one embodiment of an improvement to the bit holder shown in FIGURES 3-5. In FIGURES 6-9 a moveable floor plate is illustrated on which the free end of a drill bit can rest. The floor plate is moveable to accommodate different sizes of drill bits having longer or shorter stems. The floor plate positioning is controller by a linerar actuator. In the embodiments illustrated the linear actuator is an electro-mechanical actuator having a threaded rod as best shown in FIGURE 10 that is rotated using a gear assembly powered by an electric motor. The moveable floor plate is mounted on a bracket moveable up and/or down on vertical support member.
The threaded rod extends through a threaded block on the bracket. As the threaded rod is rotated the bracket moves up or down.
On advantage of the moveable floor plate of the present invention is that after a button has been ground the pressure plate holding the bit in position is backed off slightly so that the bit can be rotated to position the next button to be ground. The moveable floor plate supports the bit without assistance from the operator.
Another advantage is that the floor plate can be moved up or down so the bit is supported by pressure plate near the working surface of the bit rather than down the shank of the bit. This provides better support during grinding.
Having illustrated and described a preferred embodiment of the invention and certain possible modifications thereto, it should be apparent to those of ordinary skill in the art that the invention permits of further modification in arrangement and detail and is not restricted to the specific semi-automatic grinding apparatus illustrated.
It will be appreciated that the above description related to the preferred embodiment by way of example only.
Many variations on the invention will be obvious to those knowledgeable in the field, and such obvious variations are within the scope of the invention as described and claimed, whether or not expressly described.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A grinding apparatus for grinding the hard metal inserts of rock drill bits, said grinding apparatus having a grinding machine carried on an support system and means for holding one or more bits to be ground, said grinding machine equipped with a grinding cup driven by a motor to rotate about its longitudinal axis, wherein the support system comprises an arm or lever system to control movement of the grinding machine for alignment of the grinding machine with a hard metal insert to be ground, means to provide grinding pressure, means to monitor and control one or more operational functions of the grinding apparatus selected from the group consisting of force, grinding pressure, movement and speed of movement of the grinding machine during alignment with a hard metal insert wherein the means for holding one or more rock drill bits to be ground has one or more apertures to hold one or more rock drill bits to be ground includes a moveable floor plate for each aperature to support a free end of a shank on the bit to be held in the aperature.
2. A grinding apparatus according to claim 1 wherein the moveable floor plate is controlled by a linear actuator.
3. A grinding apparatus according to claim 1 or 2 wherein the means for holding one or more rock drill bits to be ground includes a moveable pressure plate for each aperature wherein the shank of a bit is held between said pressure plate and the sides of one of said aperatures wherein movement of said pressure plate is controlled by a linear actuator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3048079A CA3048079A1 (en) | 2019-06-25 | 2019-06-25 | Improved bit holder for grinding apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3048079A CA3048079A1 (en) | 2019-06-25 | 2019-06-25 | Improved bit holder for grinding apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3048079A1 true CA3048079A1 (en) | 2020-12-25 |
Family
ID=74036629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3048079A Pending CA3048079A1 (en) | 2019-06-25 | 2019-06-25 | Improved bit holder for grinding apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA3048079A1 (en) |
-
2019
- 2019-06-25 CA CA3048079A patent/CA3048079A1/en active Pending
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