CA2313749A1 - Flexible shaft drill bit with removable cutting head - Google Patents
Flexible shaft drill bit with removable cutting head Download PDFInfo
- Publication number
- CA2313749A1 CA2313749A1 CA 2313749 CA2313749A CA2313749A1 CA 2313749 A1 CA2313749 A1 CA 2313749A1 CA 2313749 CA2313749 CA 2313749 CA 2313749 A CA2313749 A CA 2313749A CA 2313749 A1 CA2313749 A1 CA 2313749A1
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- drill bit
- cutting head
- shaft
- short shaft
- threaded
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Abstract
The present invention features a self-feeding, wood-boring drill bit. A two-piece bit has a threaded pilot point as part of the shaft. The cutting head has an axial through-bore which is threaded to receive the pilot point, so the two parts are held together in threaded engagement.
An extended bearing surface area or bearing neck is also provided between the cutting head and the shaft, in addition to the threaded joint area. This structure spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure. Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. A long, flexible shaft is welded to the driving end of the cutting head assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
An extended bearing surface area or bearing neck is also provided between the cutting head and the shaft, in addition to the threaded joint area. This structure spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure. Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. A long, flexible shaft is welded to the driving end of the cutting head assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
Description
FLEXIBLE SHAFT DRILL BIT WITH REMOVABLE CUTTING HEAD
Field of the Invention:
The present invention relates to wood-drilling bits and, more particularly, to a flexible shaft drill bit with removable cutting head.
BACKGROUND OF THE INVENTION
Self-feeding wood bits with relatively heavy cutting heads are known in the art. Those bits have a pilot point with threads which pull the bit into the wood. They perform better than spade bits, because they cut faster and require little axial force. With a heavier cutting head, it becomes quite difficult and expensive to form the bit as a single piece. Therefore, the tendency in the art had been to make the bit in several pieces and then fasten them together by various means. Often, the cutting head was welded or otherwise joined to the shaft, and the piloting point was inserted into a square or other non-circular hole and held in place with a set screw.
Docket No. BES-lOICAN - 1 -As might be expected, the piloting points tended to work loose from the rest of the bit. Also, the cost of welding pieces together was a substantial part of the cost of manufacturing these bits.
A bit which does not require welding is shown in U.S.
Patent No. 2,593,823 issued to Wilson. That bit is intended for relatively light duty. In the Wilson patent, the cutting head of the bit is very short, which means that there is little thread engagement between the shaft and the cutting head, causing instability of the head relative to the shaft. In that threaded arrangement, most of the forces between the cutting head and the shaft are borne in a very small area near the shoulder, tending to cause failure of one or both parts at that point. Also, because the cutting head is so short, there is instability between the cutting head and the workpiece.
United States Patent No. 5,193,951, issued to Schimke for WOOD-DRILLING BIT, and hereby incorporated by reference, discloses a two-piece bit in which a threaded pilot point is part of the shaft. The cutting head has an axial through-bore which is threaded to receive the pilot point, so the two parts are held together in threaded engagement.
The threaded joint between the shaft and cutting head is Docket No. BES-lOICAN - 2 -also glued together with a permanent glue to fill the spaces between threads and reduce the opportunity for misalignment between the head and shaft. The cutting head is therefore not removable relative to the short shaft. An extended bearing surface area or bearing neck is provided between the cutting head and the shaft, in addition to the threaded joint area, to improve alignment between the head and the shaft and to spread the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure.
Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. There is no need for welding the head itself, thus reducing the cost of manufacture. Finally, pilot points cannot work loose. The Schimke patent also contemplates a conventionally short shaft (albeit longer than the Wilson shaft, supra), the driving end of which is adapted to fit into the chuck of a drill.
It has long been known, however, that workers are often located at a relatively great distance from the surface to be drilled. This occurs when obstructions are disposed between the work surface and the worker, for example. It Docket No. BES-lOICAN - 3 -can also occur when drilling inside a hollow wall, the dimensions of which do not permit a body or even a hand to enter.
Once the drill bit or cutting head, itself, has been used extensively or has been used to drill into hard materials, it is not unusual for the head to be dulled.
Unfortunately, it can be rather expensive to replace the entire assembly of drill bit and shaft when it is the cutting head alone that must be replaced.
It would be advantageous, therefore, to provide a drill bit attached to a long shaft.
It would also be advantageous to provide such a drill bit and shaft with the capability to remove the worn cutting head from the shaft.
It would further be advantageous to provide a cutting head removably attached to a long, flexible shaft, the composite article forming a drill bit.
Docket No. BES-lOICAN - 4 -SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a self-feeding, wood-boring bit. A two-piece bit has a threaded pilot point as part of the short shaft. The cutting head has an axial through-bore which is threaded to receive the pilot point, so the two parts are held together in threaded engagement. An extended bearing surface area or bearing neck is also provided between the cutting head and the short shaft, in addition to the threaded joint area.
This structure improves alignment between the head and the shaft and spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure.
Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. A long, flexible shaft is welded to the driving end of the drill bit shaft assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
Docket No. BES-lOICAN - 5 -BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent detailed description, in which:
FIGURE 1 is a front view of the drill bit that forms part of the present invention;
FIGURE 2 is a front sectional view of the drill bit of FIGURE 1; and FIGURE 3 is a side view of the drill bit and conventional shaft attached to a long, flexible shaft, in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Generally speaking, the invention is a self-feeding, wood-boring bit consisting of a cutting head removably attached to a long, flexible shaft. The two-piece bit has a threaded pilot point as part of the shaft. The cutting head has an axial through-bore which is threaded to receive the Docket No. BES-lOICAN - 6 -pilot point, so the two parts are held together in threaded engagement. An extended bearing surface area or bearing neck is also provided between the cutting head and the shaft, in addition to the threaded joint area. This structure improves alignment between the head and the shaft and spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure. A long, flexible shaft is welded to the driving end of the drill bit shaft assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
Referring now to FIGURES 1 and 2, the drill bit 10 that forms a part of the present invention is made up of two parts: a short, conventional shaft 12 and a cutting head 14. The short shaft 12 has an extended central portion 16 with a circular cross-section. At one end of the central portion 16 is a driving end 18.
At the other end of the central portion 16 is a pilot point 20 which is threaded with tapering male threads 22 in the same way as a standard wood screw is threaded. Pilot point 20 ends in a sharp pointed tip 42. There is a bearing portion or bearing neck portion 23 on the shaft 12 between Docket No. BES-lOICAN - 7 -the central portion 16 and the threaded point 20. The bearing portion 23 has a smaller diameter than does the central portion 16. An upper shoulder portion 24 is disposed between the central portion 16 and the bearing portion 23. The upper shoulder portion 24 has a larger diameter than does the largest diameter of the threaded male end 20.
There is a slight reduction in diameter from the bearing portion 23 of the shaft 12 to the threaded end portion 20 forming a lower shoulder portion 25; and a corresponding reduction in diameter from the mating bearing portion 27 in the head 14 to the mating threaded portion 28 of the head 14. This is necessary in order for the threaded portion 20 of the shaft 12 to readily pass through the bearing portion 26 of the head 14 during assembly.
The cutting head 14 has an axial through-bore 26 which has female threads in its lower portion 28 that are adapted to receive the male threads 22 of the pilot point 20 in threaded engagement. The upper sleeve portion 27 of the through-bore is unthreaded and has a larger cross-sectional diameter than does the lower portion 28, defining a medial shoulder portion 29. The upper sleeve portion 27 is sized to receive the unthreaded bearing neck portion 23, while the Docket No. BES-lOICAN - 8 -medial shoulder portion 29 is sized to receive the lower shoulder portion 25 of the shaft 12 with a snug fit. This sleeve portion 27 is preferably 5/8 inch long, but must be at least 1/4 inch long. The total length of the threaded pilot point 20 and the bearing portion 23 is longer than the length of the cutting head 14 along the central axis so that, when the cutting head 14 is threaded onto the pilot point 20, the end of the pilot point 20 projects outwardly beyond the cutting head 14. The top surface 30 of the cutting head 14 abuts the upper shoulder portion 24, thereby preventing the cutting head 14 from moving farther inwardly on the shaft 12.
The large bearing surface area between the unthreaded upper sleeve portion 27 of the cutting head 14 and the unthreaded bearing portion 23 of the shaft 12 provides for proper alignment of the head 14 with the shaft 12. This large bearing surface area also causes bending and shear forces on the shaft 12 to be greatly reduced, thereby reducing the opportunity for failure of the shaft 12.
When the bit 10 is driven by a drill (not shown), the force of the wood or other substrate (not shown) on the cutting head 14 is in a direction which would further tighten the cutting head 14 onto the shaft 12. Thus, there Docket No. BES-lOICAN - 9 -is no tendency for the cutting head 14 to work loose from the shaft 12 during use.
The cutting head 14 has front and back surfaces 32, 33, respectively, which terminate at the sides in edges 34. The forwardmost portions of the edges 34 are the cutting points 40. Cutting edges 41 extend from the cutting points 40 radially inward to the bore 28.
The cutting head 14 has a rounded outer surface, including trailing wings 36. The trailing wings 36 are recessed radially inward from the cutting points 40 and provide stability to the drill bit.
When drilling begins, the pointed tip 42 of the pilot point 20 enters the wood or other substrate to keep the bit 10 centered on the substrate. The threads 22 on the pilot point 20 begin to pull the bit 10 into the substrate. When the cutting points 40 reach the substrate, they begin to cut into the substrate. Then, the cutting edges 41 begin cutting forward into the substrate, shaving the substrate into small pieces which pass upwardly in front of the respective face 32 or 33 and out the top of the hole. As the bit rotates in a clockwise direction, the cutting force of the bit on the substrate is exerted in a clockwise Docket No. BES-lOlCAN - 10 -direction, and the opposing force from the substrate is exerted in the opposite (counterclockwise) direction, thereby causing the cutting head 14 to be tightened further inward onto the pilot point 20 to tightly abut the shoulder 24.
In the preferred method of manufacture of the bit 10 (best seen in FIGURE 2), the shaft 12 is formed as one piece, and the cutting head 14 is cast as one piece. Then the faces 32, 33 are ground to sharpen the cutting edges 41.
In order to make the axial through-bore 26 in the cutting head 14, first a hole is drilled through the cutting head 14 with the diameter the same as the minor diameter of the threads 28. Then, the upper sleeve portion 27 is drilled to a diameter larger than the major diameter of the threads 27.
The threads 27 are then tapped in the lower portion of the cutting head 14. Threads 22 are also cut into the tapered pilot point 20. The bit is then assembled simply by threading the cutting head 14 onto the shaft 12 until it abuts the shoulder 24.
Referring now also to FIGURE 3, connected to the driving end 18 of the short, conventional shaft 12 is a long, flexible shaft 44, on the order of four to six feet long. Both the driving end 18 of shaft 12 and the proximal Docket No. BES-lOICAN - 11 -end of flexible shaft 44 are tapered. They abut at their respective points, shown generally at reference numeral 45.
A welding process, such as metal inert gas (MIG) welding in the preferred embodiment, is used to permanently connect both of the shafts 12 and 44 together. Once the weld is accomplished, the outer surface of the composite unit is ground by a process well known to those skilled in the art, in order to reduce the cross section at the weld itself, and to provide a unitary, flexible shaft 12, 44 that is connected to the removable cutting head 14. The distal end of the long, flexible shaft 44 can also be configured with a hexagonal cross-section, as shown, to facilitate its insertion into and use with the chuck of a drill, not shown.
Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
Docket No. BES-lOICAN - 12 -
Field of the Invention:
The present invention relates to wood-drilling bits and, more particularly, to a flexible shaft drill bit with removable cutting head.
BACKGROUND OF THE INVENTION
Self-feeding wood bits with relatively heavy cutting heads are known in the art. Those bits have a pilot point with threads which pull the bit into the wood. They perform better than spade bits, because they cut faster and require little axial force. With a heavier cutting head, it becomes quite difficult and expensive to form the bit as a single piece. Therefore, the tendency in the art had been to make the bit in several pieces and then fasten them together by various means. Often, the cutting head was welded or otherwise joined to the shaft, and the piloting point was inserted into a square or other non-circular hole and held in place with a set screw.
Docket No. BES-lOICAN - 1 -As might be expected, the piloting points tended to work loose from the rest of the bit. Also, the cost of welding pieces together was a substantial part of the cost of manufacturing these bits.
A bit which does not require welding is shown in U.S.
Patent No. 2,593,823 issued to Wilson. That bit is intended for relatively light duty. In the Wilson patent, the cutting head of the bit is very short, which means that there is little thread engagement between the shaft and the cutting head, causing instability of the head relative to the shaft. In that threaded arrangement, most of the forces between the cutting head and the shaft are borne in a very small area near the shoulder, tending to cause failure of one or both parts at that point. Also, because the cutting head is so short, there is instability between the cutting head and the workpiece.
United States Patent No. 5,193,951, issued to Schimke for WOOD-DRILLING BIT, and hereby incorporated by reference, discloses a two-piece bit in which a threaded pilot point is part of the shaft. The cutting head has an axial through-bore which is threaded to receive the pilot point, so the two parts are held together in threaded engagement.
The threaded joint between the shaft and cutting head is Docket No. BES-lOICAN - 2 -also glued together with a permanent glue to fill the spaces between threads and reduce the opportunity for misalignment between the head and shaft. The cutting head is therefore not removable relative to the short shaft. An extended bearing surface area or bearing neck is provided between the cutting head and the shaft, in addition to the threaded joint area, to improve alignment between the head and the shaft and to spread the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure.
Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. There is no need for welding the head itself, thus reducing the cost of manufacture. Finally, pilot points cannot work loose. The Schimke patent also contemplates a conventionally short shaft (albeit longer than the Wilson shaft, supra), the driving end of which is adapted to fit into the chuck of a drill.
It has long been known, however, that workers are often located at a relatively great distance from the surface to be drilled. This occurs when obstructions are disposed between the work surface and the worker, for example. It Docket No. BES-lOICAN - 3 -can also occur when drilling inside a hollow wall, the dimensions of which do not permit a body or even a hand to enter.
Once the drill bit or cutting head, itself, has been used extensively or has been used to drill into hard materials, it is not unusual for the head to be dulled.
Unfortunately, it can be rather expensive to replace the entire assembly of drill bit and shaft when it is the cutting head alone that must be replaced.
It would be advantageous, therefore, to provide a drill bit attached to a long shaft.
It would also be advantageous to provide such a drill bit and shaft with the capability to remove the worn cutting head from the shaft.
It would further be advantageous to provide a cutting head removably attached to a long, flexible shaft, the composite article forming a drill bit.
Docket No. BES-lOICAN - 4 -SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a self-feeding, wood-boring bit. A two-piece bit has a threaded pilot point as part of the short shaft. The cutting head has an axial through-bore which is threaded to receive the pilot point, so the two parts are held together in threaded engagement. An extended bearing surface area or bearing neck is also provided between the cutting head and the short shaft, in addition to the threaded joint area.
This structure improves alignment between the head and the shaft and spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure.
Two different materials are used for the head and shaft, respectively, so that the head has optimum cutting capabilities and the shaft has optimum strength for transmitting torque and withstanding bending and shear stresses. A long, flexible shaft is welded to the driving end of the drill bit shaft assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
Docket No. BES-lOICAN - 5 -BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent detailed description, in which:
FIGURE 1 is a front view of the drill bit that forms part of the present invention;
FIGURE 2 is a front sectional view of the drill bit of FIGURE 1; and FIGURE 3 is a side view of the drill bit and conventional shaft attached to a long, flexible shaft, in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Generally speaking, the invention is a self-feeding, wood-boring bit consisting of a cutting head removably attached to a long, flexible shaft. The two-piece bit has a threaded pilot point as part of the shaft. The cutting head has an axial through-bore which is threaded to receive the Docket No. BES-lOICAN - 6 -pilot point, so the two parts are held together in threaded engagement. An extended bearing surface area or bearing neck is also provided between the cutting head and the shaft, in addition to the threaded joint area. This structure improves alignment between the head and the shaft and spreads the forces over a large bearing surface, which greatly reduces the opportunity for shaft failure. A long, flexible shaft is welded to the driving end of the drill bit shaft assembly, to provide for drilling operations at a distance from the worker. The cutting head, itself, can be unscrewed and detached from the long, flexible shaft, so that it can be replaced with a new head, when required.
Referring now to FIGURES 1 and 2, the drill bit 10 that forms a part of the present invention is made up of two parts: a short, conventional shaft 12 and a cutting head 14. The short shaft 12 has an extended central portion 16 with a circular cross-section. At one end of the central portion 16 is a driving end 18.
At the other end of the central portion 16 is a pilot point 20 which is threaded with tapering male threads 22 in the same way as a standard wood screw is threaded. Pilot point 20 ends in a sharp pointed tip 42. There is a bearing portion or bearing neck portion 23 on the shaft 12 between Docket No. BES-lOICAN - 7 -the central portion 16 and the threaded point 20. The bearing portion 23 has a smaller diameter than does the central portion 16. An upper shoulder portion 24 is disposed between the central portion 16 and the bearing portion 23. The upper shoulder portion 24 has a larger diameter than does the largest diameter of the threaded male end 20.
There is a slight reduction in diameter from the bearing portion 23 of the shaft 12 to the threaded end portion 20 forming a lower shoulder portion 25; and a corresponding reduction in diameter from the mating bearing portion 27 in the head 14 to the mating threaded portion 28 of the head 14. This is necessary in order for the threaded portion 20 of the shaft 12 to readily pass through the bearing portion 26 of the head 14 during assembly.
The cutting head 14 has an axial through-bore 26 which has female threads in its lower portion 28 that are adapted to receive the male threads 22 of the pilot point 20 in threaded engagement. The upper sleeve portion 27 of the through-bore is unthreaded and has a larger cross-sectional diameter than does the lower portion 28, defining a medial shoulder portion 29. The upper sleeve portion 27 is sized to receive the unthreaded bearing neck portion 23, while the Docket No. BES-lOICAN - 8 -medial shoulder portion 29 is sized to receive the lower shoulder portion 25 of the shaft 12 with a snug fit. This sleeve portion 27 is preferably 5/8 inch long, but must be at least 1/4 inch long. The total length of the threaded pilot point 20 and the bearing portion 23 is longer than the length of the cutting head 14 along the central axis so that, when the cutting head 14 is threaded onto the pilot point 20, the end of the pilot point 20 projects outwardly beyond the cutting head 14. The top surface 30 of the cutting head 14 abuts the upper shoulder portion 24, thereby preventing the cutting head 14 from moving farther inwardly on the shaft 12.
The large bearing surface area between the unthreaded upper sleeve portion 27 of the cutting head 14 and the unthreaded bearing portion 23 of the shaft 12 provides for proper alignment of the head 14 with the shaft 12. This large bearing surface area also causes bending and shear forces on the shaft 12 to be greatly reduced, thereby reducing the opportunity for failure of the shaft 12.
When the bit 10 is driven by a drill (not shown), the force of the wood or other substrate (not shown) on the cutting head 14 is in a direction which would further tighten the cutting head 14 onto the shaft 12. Thus, there Docket No. BES-lOICAN - 9 -is no tendency for the cutting head 14 to work loose from the shaft 12 during use.
The cutting head 14 has front and back surfaces 32, 33, respectively, which terminate at the sides in edges 34. The forwardmost portions of the edges 34 are the cutting points 40. Cutting edges 41 extend from the cutting points 40 radially inward to the bore 28.
The cutting head 14 has a rounded outer surface, including trailing wings 36. The trailing wings 36 are recessed radially inward from the cutting points 40 and provide stability to the drill bit.
When drilling begins, the pointed tip 42 of the pilot point 20 enters the wood or other substrate to keep the bit 10 centered on the substrate. The threads 22 on the pilot point 20 begin to pull the bit 10 into the substrate. When the cutting points 40 reach the substrate, they begin to cut into the substrate. Then, the cutting edges 41 begin cutting forward into the substrate, shaving the substrate into small pieces which pass upwardly in front of the respective face 32 or 33 and out the top of the hole. As the bit rotates in a clockwise direction, the cutting force of the bit on the substrate is exerted in a clockwise Docket No. BES-lOlCAN - 10 -direction, and the opposing force from the substrate is exerted in the opposite (counterclockwise) direction, thereby causing the cutting head 14 to be tightened further inward onto the pilot point 20 to tightly abut the shoulder 24.
In the preferred method of manufacture of the bit 10 (best seen in FIGURE 2), the shaft 12 is formed as one piece, and the cutting head 14 is cast as one piece. Then the faces 32, 33 are ground to sharpen the cutting edges 41.
In order to make the axial through-bore 26 in the cutting head 14, first a hole is drilled through the cutting head 14 with the diameter the same as the minor diameter of the threads 28. Then, the upper sleeve portion 27 is drilled to a diameter larger than the major diameter of the threads 27.
The threads 27 are then tapped in the lower portion of the cutting head 14. Threads 22 are also cut into the tapered pilot point 20. The bit is then assembled simply by threading the cutting head 14 onto the shaft 12 until it abuts the shoulder 24.
Referring now also to FIGURE 3, connected to the driving end 18 of the short, conventional shaft 12 is a long, flexible shaft 44, on the order of four to six feet long. Both the driving end 18 of shaft 12 and the proximal Docket No. BES-lOICAN - 11 -end of flexible shaft 44 are tapered. They abut at their respective points, shown generally at reference numeral 45.
A welding process, such as metal inert gas (MIG) welding in the preferred embodiment, is used to permanently connect both of the shafts 12 and 44 together. Once the weld is accomplished, the outer surface of the composite unit is ground by a process well known to those skilled in the art, in order to reduce the cross section at the weld itself, and to provide a unitary, flexible shaft 12, 44 that is connected to the removable cutting head 14. The distal end of the long, flexible shaft 44 can also be configured with a hexagonal cross-section, as shown, to facilitate its insertion into and use with the chuck of a drill, not shown.
Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
Docket No. BES-lOICAN - 12 -
Claims (18)
1. A drill bit having a replaceable cutting head, comprising:
a short shaft comprising a driving end, a central portion, an upper shoulder portion having an extended bearing portion forming a cylindrical bearing neck along the longitudinal axis of said short shaft and, projecting downwardly from said bearing neck, a threaded male end having a pointed tip to serve as a pilot;
a removable cutting head defining an axially stepped through-bore comprising a threaded lower portion to receive said threaded male end of said short shaft in threaded engagement and an unthreaded upper sleeve portion that receives the bearing neck with a snug fit; and an elongated shaft connected to said short shaft, forming a unitary extension thereof to allow a worker to drill material disposed a predetermined distance therefrom.
a short shaft comprising a driving end, a central portion, an upper shoulder portion having an extended bearing portion forming a cylindrical bearing neck along the longitudinal axis of said short shaft and, projecting downwardly from said bearing neck, a threaded male end having a pointed tip to serve as a pilot;
a removable cutting head defining an axially stepped through-bore comprising a threaded lower portion to receive said threaded male end of said short shaft in threaded engagement and an unthreaded upper sleeve portion that receives the bearing neck with a snug fit; and an elongated shaft connected to said short shaft, forming a unitary extension thereof to allow a worker to drill material disposed a predetermined distance therefrom.
2. The drill bit as recited in claim 1, wherein, upon assembly, said cutting head abuts said upper shoulder portion of said short shaft.
3. The drill bit as recited in claim 2, wherein said upper shoulder portion of said short shaft is located axially inward from said pointed tip a distance that is greater than the length of said axial through-bore of said cutting head, so that, upon assembly, said unthreaded cutting head is abutting said upper shoulder of said short shaft, wherein said pointed tip of said threaded male end projects outwardly beyond said cutting head.
4. The drill bit of claim 1, wherein said bearing neck is longer in length along the longitudinal axis of said short shaft than said shoulder portion of said short shaft.
5. The drill bit of claim 1, wherein said bearing neck is at least one-fourth of an inch long with respect to the longitudinal axis of said short shaft.
6. The drill bit of claim 1, further including at least one set of flats on said driving end.
7. The drill bit of claim 1, wherein said cutting head comprises a main body defining a pair of front and a back surfaces terminating at the sides to form a pair of edges, a pair of cutting points formed at the forwardmost portions of said edges, and a pair of cutting edges extending from said cutting points radially inward to said short shaft.
8. The drill bit of claim 7, wherein said cutting head has a rounded outer surface to provide stability to said drill bit.
9. The drill bit of claim 7, including a pair of trailing wings recessed radially inward from said cutting points to provide stability to said drill bit.
10. The drill bit of claim 1, wherein said cutting head comprises harder material than that of said short shaft.
11. The drill bit of claim 1, wherein said short shaft comprises tougher material than said cutting head.
12. The drill bit of claim 1, wherein said elongated shaft comprises a flexible shaft.
13. The drill bit of claim 1, wherein said elongated shaft is connected to said short shaft by means of welding.
14. The drill bit of claim 13, wherein said welding comprises metal inert gas (MIG) welding.
15. A drill bit having a replaceable cutting head, comprising:
a short shaft comprising a driving end, a central portion, an upper shoulder portion having an extended bearing portion forming a cylindrical bearing neck along the longitudinal axis of said short shaft and, projecting downwardly from said bearing neck, a threaded male end having a pointed tip to serve as a pilot;
a removable cutting head defining an axially stepped through-bore comprising a threaded lower portion to receive said threaded male end of said short shaft in threaded engagement and an unthreaded upper sleeve portion that receives the bearing neck with a snug fit; and a flexible shaft welded to said short shaft, forming a unitary extension thereof to allow a worker to drill material disposed a predetermined distance therefrom.
a short shaft comprising a driving end, a central portion, an upper shoulder portion having an extended bearing portion forming a cylindrical bearing neck along the longitudinal axis of said short shaft and, projecting downwardly from said bearing neck, a threaded male end having a pointed tip to serve as a pilot;
a removable cutting head defining an axially stepped through-bore comprising a threaded lower portion to receive said threaded male end of said short shaft in threaded engagement and an unthreaded upper sleeve portion that receives the bearing neck with a snug fit; and a flexible shaft welded to said short shaft, forming a unitary extension thereof to allow a worker to drill material disposed a predetermined distance therefrom.
16. The drill bit of claim 15, wherein said flexible shaft is welded to said short shaft by means of metal inert gas (MIG) welding.
17. The drill bit of claim 16, wherein said cutting head comprises harder material than that of said short shaft.
18. The drill bit of claim 16, wherein said short shaft comprises tougher material than said cutting head.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52005300A | 2000-03-07 | 2000-03-07 | |
| US09/520,053 | 2000-03-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2313749A1 true CA2313749A1 (en) | 2001-09-07 |
Family
ID=24071002
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2313749 Abandoned CA2313749A1 (en) | 2000-03-07 | 2000-07-12 | Flexible shaft drill bit with removable cutting head |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2313749A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2435627A (en) * | 2006-03-02 | 2007-09-05 | Milwaukee Electric Tool Corp | A boring bit with a removable blade held by a quick release lock |
| US7909547B2 (en) | 2005-10-08 | 2011-03-22 | Milwaukee Electric Tool Corporation | Replaceable tip for a bit or auger bit |
| US8328477B2 (en) | 2006-03-02 | 2012-12-11 | Milwaukee Electric Tool Corporation | Cutting tool |
| US9500038B2 (en) | 2013-02-01 | 2016-11-22 | Milwaukee Electric Tool Corporation | Auger bit with replaceable cutting bit |
| CN115255819A (en) * | 2022-07-13 | 2022-11-01 | 西安远方航空技术发展有限公司 | Measuring rake forming processing method |
-
2000
- 2000-07-12 CA CA 2313749 patent/CA2313749A1/en not_active Abandoned
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7909547B2 (en) | 2005-10-08 | 2011-03-22 | Milwaukee Electric Tool Corporation | Replaceable tip for a bit or auger bit |
| US8109700B2 (en) | 2005-10-08 | 2012-02-07 | Milwaukee Electric Tool Corporation | Replaceable tip for a bit or auger bit |
| US8371777B2 (en) | 2006-03-02 | 2013-02-12 | Milwaukee Electric Tool Corporation | Cutting tool |
| US7661911B2 (en) | 2006-03-02 | 2010-02-16 | Milwaukee Electric Tool Corporation | Cutting tool |
| GB2435627B (en) * | 2006-03-02 | 2012-04-11 | Milwaukee Electric Tool Corp | Cutting tool |
| US8328477B2 (en) | 2006-03-02 | 2012-12-11 | Milwaukee Electric Tool Corporation | Cutting tool |
| GB2435627A (en) * | 2006-03-02 | 2007-09-05 | Milwaukee Electric Tool Corp | A boring bit with a removable blade held by a quick release lock |
| CN103302337A (en) * | 2006-03-02 | 2013-09-18 | 密尔沃基电动工具公司 | Cutting tool |
| US9339874B2 (en) | 2006-03-02 | 2016-05-17 | Milwaukee Electric Tool Corporation | Cutting tool |
| CN103302337B (en) * | 2006-03-02 | 2016-09-28 | 密尔沃基电动工具公司 | Cutting tool |
| US10618119B2 (en) | 2006-03-02 | 2020-04-14 | Milwaukee Electric Tool Corporation | Cutting tool |
| US9500038B2 (en) | 2013-02-01 | 2016-11-22 | Milwaukee Electric Tool Corporation | Auger bit with replaceable cutting bit |
| CN115255819A (en) * | 2022-07-13 | 2022-11-01 | 西安远方航空技术发展有限公司 | Measuring rake forming processing method |
| CN115255819B (en) * | 2022-07-13 | 2024-04-16 | 西安远方航空技术发展有限公司 | Measuring rake forming processing method |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| FZDE | Dead |