AU2021107344A4

AU2021107344A4 - Controller for a Drill

Info

Publication number: AU2021107344A4
Application number: AU2021107344A
Authority: AU
Inventors: Bruce Mcrae Allen; Kathryn Beech; Thomas James Drummond Clarkson; James Filear; Hans Kunz; Carlos Uribe
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-11-18
Filing date: 2021-08-25
Publication date: 2021-12-16
Anticipated expiration: 2029-08-25

Abstract

A controller for controlling a motor of a drill comprising an output of a signal for controlling a speed of rotation of the motor, a processor for producing the signal, wherein the signal is automatically varied according to a waveform, wherein one or more characteristics of the waveform is determined by a material to be drilled and/or a diameter of the bit. - 1/4 20 INPUTS 30 MOTOR CONTROLLER MODULE 1 10 DRILL 1 FIGURE 1

Description

- 1/4

20 INPUTS

30 MOTOR CONTROLLER MODULE

1 10

DRILL

1

FIGURE 1

Controller for a Drill

Field of the Invention

[0001] The present invention relates to a controller and a method for controlling a drill.

Background

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[0003] The efficiency of drilling a hole in a workpiece is dependent on a number of factors including, but not limited to, the material which the work piece is made from, the size of the drill bit, the type of drill being used, the force applied to the drill and the angle at which the drill is oriented relative to the workpiece.

[0004] The speed at which the drill bit rotates can affect the rate of penetration into a workpiece. In some instances where the speed is too slow, the drill bit may stall. In other instances where the speed in too fast, the cutting edge of the drill bit may not have an adequate opportunity to engage with the workpiece and instead will rotate above the workpiece within the hole.

[0005] Throughout the specification unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group ofintegers.

[0006] Throughout the specification unless the context requires otherwise, the word "include" or variations such as "includes" or "including", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group ofintegers.

Summary of Invention

[0007] According to a first aspect of the present invention, there is provided a drill comprising:

a controller configured to automatically vary a speed of rotation of a bit according to a waveform having a characteristic selected according to a material being drilled and/or a diameter of the bit.

[0008]In an embodiment, the controller comprises an input for selection of the material being drilled. Alternatively, the controller comprises an input for a frequency of a period of the waveform.

[0009]In an embodiment, the range of amplitude of the waveform is selected according to a diameter of the bit.

[0010]In an embodiment, the controller comprises an input for selection of a range of amplitudes of the waveform. Alternatively, the controller comprises an input for an offset of the waveform. Alternatively, the controller comprises an input for the diameter of the bit.

[0011]In an embodiment, the controller comprises an input for selection of the type of drill bit.

[0012]In an embodiment, the speed of rotation of the bit is varied by controlling a voltage supplied to a motor of the drill according to an amplitude of the waveform.

[0013]In an embodiment, a torque is applied to the bit during a part of the waveform having a negative gradient.

[0014]In an embodiment, the frequency of the waveform is selected for at least drilling of steel, wood, hard rock and/or masonry. In an embodiment, the frequency of the waveform is selected for screwing of a self-tapping screw.

[0015]In an embodiment, the frequency for the material being drilled is selected so as to provide the bit with the opportunity to cut the material across the radius of a cutting edge of the bit in an efficient manner.

[0016]In an embodiment, the frequency for the material being drilled is selected such that the bit rotates at a speed substantially optimised for a radial point on the cutting edge for long enough to cut the material at that radius before the speed changes to be substantially optimised for a different radial position on the cutting edge.

[0017]In an embodiment, the voltage is varied during operation of the drill between a maximum voltage and a minimum voltage.

[0018]In an embodiment, the maximum voltage is limited by capacity of the drill.

[0019]In an embodiment, the minimum voltage is zero volts. In alternative embodiments, the minimum voltage is greater than zero.

[0020]In an embodiment, the waveform is substantially a sinusoidal waveform. Alternatively, the waveform is a sawtooth waveform. Alternatively, the waveform is a triangular waveform.

[0021]In an embodiment, a maximum power is delivered to the bit at a peak of the waveform.

[0022]In an embodiment, a minimum power is delivered to the bit at a trough of the waveform.

[0023]According to a second aspect of the present invention, there is provided a controller for controlling a motor of a drill comprising:

an output of a signal for controlling a speed of rotation of the motor,

a processor for producing the signal, wherein the signal is automatically varied according to a waveform, wherein one or more characteristics of the waveform is determined by a material to be drilled and/or a diameter of the bit.

[0024]In an embodiment, the one or more characteristics of waveform comprises one or more of: amplitude, frequency, and offset.

[0025]In an embodiment, the processor is configured to determine the frequency according to the material.

[0026]In an embodiment, the processor is configured to determine the amplitude according to the diameter of the bit.

[0027]According to a third aspect of the present invention, there is provided a computer program for controlling the speed of rotation of a motor of a drill, the computer program comprising:

instructions for execution by a processor which cause the motor of the drill to be controlled such that a speed of rotation of the motor is automatically varied according to a waveform, wherein one of more characteristics of the waveform is determined by a material to be drilled and/or a diameter of the bit.

[0028]In an embodiment, the frequency is determined by selection of the material to be drilled.

[0029]In an embodiment, the amplitude is determined by selection of the diameter of the bit.

[0030]In an embodiment, the computer program comprising computer executable instructions stored in a non-transient manner for controlling a processor of a drill to perform one or more of the methods defined below.

[0031]According to a fourth aspect of the present invention, there is provided a method of controlling the speed of rotation of a drill comprising:

providing a signal to control the speed of rotation of a motor of the drill, the output signal comprising a voltage automatically varied according to a waveform;

wherein one or more characteristics of the waveform is determined by the material to be drilled or a diameter of the bit.

[0032]In an embodiment, the frequency is determined according to the material to be drilled.

[0033]In an embodiment, the amplitude is determined according to the diameter of the bit.

[0034] According to a fifth aspect of the present invention, there is provided a method of drilling comprising:

controlling a speed of rotation of a bit by the drill as it is drilled into a workpiece, wherein the speed is controlled by automatically varying the rotation of the bit according to a material from which the workpiece is formed and/or according to a diameter of the bit.

[0035]In an embodiment, a frequency of the speed of rotation of the bit is automatically varied according to the material to be drilled.

[0036]In an embodiment, an amplitude of the speed of rotation of the bit is automatically varied according to the diameter of the bit.

[0037] According to a sixth aspect of the present invention, there is provided a drill comprising:

a controller configured to automatically vary a speed of rotation of a bit according to a waveform having a frequency selected according to a material being drilled.

[0038] According to a seventh aspect of the present invention, there is provided a drill comprising:

a controller configured to automatically vary a speed of rotation of a bit according to a waveform having an amplitude selected according to a diameter of a bit.

Brief Description of Drawings

[0039] In order to provide a better understanding, embodiments of the present invention will be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a block diagram of the components of an embodiment of the present invention;

Figure 2 is a speed curve of a drill motor which is offset and varies according to a waveform according to an embodiment of the present invention;

Figure 3 is a side-by-side view of different waveforms which the drill motor speed may be varied according to according to an embodiment of the present invention;

Figure 4 is a plot of the change of amplitude of the speed curve according to an embodiment of the present invention;

Figure 5 is a plot of the change of frequency of the speed curve according to an embodiment of the present invention; and

Figure 6 is a circuit diagram of an example of the motor controller module of Figure 1.

Description of Embodiments

[0040] Referring to Figure 1, there is provided a block diagram of the components of the present invention. There is provided a drill 10 comprising a control panel. The control panel comprises one or more inputs 20 for controlling a drill so as to automatically vary a speed of a drill motor, and by extension a bit engaged by the drill 10. A motor controller module 30 receives the inputs and controls the drill 10 according to the one or more inputs 20 selected on the control panel. The inputs 20 chosen to vary the speed of the drill motor according to a waveform having a characteristic which selected according to the material which the workpiece is made and/or a diameter of a drill bit engaged by the drill 10. Reference to drilling speed typically means the 'revolutions per minute' of the drill motor and therefore, the drill bit.

[0041] The motor controller module 30 may comprise a processor, a storage device, a motor speed controller and a power supply. In the present embodiment, the motor controller module 30 is embodied using a microcontroller, such as an Arduino@ microcontroller, and a motor speed controller. The person skilled in the art would appreciate that there are a number of alternative components and ways in which the present invention may be implemented. It is only by way of an example which the preferred embodiment is provided. The storage device may be access, updated and configured by way of known techniques.

[0042] The inputs 20 also comprises an input for selection of a mode of operation. The modes of operation may comprise forward, reverse, wave forward, and optionally wave reverse. Accordingly, the drill 10 may be used as a normal drill, in forward or reverse, or by varying the speed of the drill motor according to a waveform, in forward or optionally in reverse.

[0043] It is known that there are recommended drilling speeds based on at least the material being drilled as well as the outer diameter of the drill bit, also referred to as the size of the drill bit. These recommended drilling speeds consider only the outer diameter of the drill bit. However, the drill bit must first drill from a point of the drill bit which has a diameter which is smaller than the outer diameter of the drill bit which the recommended drilling speed is determined. For example, a 10-millimetre (mm) drill bit may come to a point. Accordingly, the drilling of a hole begins at a smaller diameter than that of the outer diameter of the drill bit. Furthermore, as the drill bit continues to cut the diameter of the cutting tip in contact and cutting the workpiece progressively increases. Among other things, the recommended drilling speeds are intended to produce an optimal drilling response. Generally speaking, as the diameter of the drill bit increases, the recommended speed decreases. Therefore, the present invention seeks to automatically vary the speed of the motor of the drill 10 through the motor controller module 30 so as to account for the change in diameter of the drill bit as it drills through a material.

[0044] The control panel may comprise inputs 20 which allow a user to select the type of material being drilled. The motor controller module 30 may then alter the operational characteristics of the drill 10 in accordance with the inputs 10. Alternatively, where the material is unknown or the drill bit size is not available, the controller comprises an input 20 which allows the user to adjust a frequency of a period of the waveform 50. Accordingly, the user may increase the speed at which the motor controller module 30 automatically varies the speed of the drill motor.

[0045] Alternatively, the control panel may comprise inputs 20 to select the diameter of the bit to automatically vary the range of an amplitude of the waveform 50. Accordingly, the input 20 may allow the user to adjust a maximum drill motor speed. As such, the drill motor would still be driven according to the waveform 50, however, the peak amplitude of the speed of the drill may be increased. The inputs 20 may also allow for the waveform which the drill motor is being driven according to is offset. As such, when the trigger is actuated on the drill, the speed of the drill may start and conform to the waveform 50. However, it will not be varied to reach the original starting speed until the trigger is released.

[0046]There are many types of drill bits which are specially designed for a particular material. The control panel may comprise an input 30 allowing the user to select the type of drill bit being used with the drill 10. This may alter the range, the maximum and/or the minimum speeds of the drill of the waveform 50.

[0047] Referring to Figure 2, there is provided a speed curve of the drill motor according to a waveform 50. In the present embodiment, the preferred waveform 50 is a sinusoidal waveform 52 (as seen in Figure 3). The sinusoidal waveform 52 was chosen for the smooth operation of the drill motor it provides. However, the present invention works with a sawtooth waveform 56 or triangular waveform 54 (as seen in Figure 3). The present invention may work with any periodic waveform such as a square wave, however, the waveform 50 mentioned above have provided the most optimal performance. The speed of rotation of the bit is varied by controlling a voltage supplied to a motor of the drill 10 according to an amplitude of the waveform 50. In the present embodiment, the motor controller within the motor controller module requires a pulse width modulated input. Accordingly, the microcontroller outputs the waveform 50 using a pulse width modulated signal to the motor speed controller within the motor controller module 30. The motor speed controller within the motor controller module 30 converts said output into a signal comprising a voltage which varies according to the waveform 50 to the drill motor.

[0048] As seen in Figure 2, the minimum speed occurring at a trough amplitude 44 of the speed curve 40 is offset 46 from zero. Accordingly, once the trigger of the drill 10 is actuated, the drill will slowly begin to increase to conform to the waveform 50 shown. As the speed of the drill is automatically varied it will range from a peak amplitude 42 to a minimum amplitude at the trough amplitude 44 continuously until the trigger is released. Again, provided the drill 10 is able to drive at the drilling recommended drilling speeds for the material and drill bit, then the drill 10 will be driven at least at two points in each period at an optimal drilling speed for the diameter of the drill which is at that time engaging with the workpiece.

[0049]During normal drilling operations, when the trigger of the drill 10 is released, the drill 10 may continue due to its momentum and be slowed down by friction of the drill motor and/or the drill bit in a workpiece. The present invention drives the drill motor applying a torque to the bit even during the varying of the speed of the drill motor according to the waveform 50 having a negative gradient. The negative gradient occurs as the speed of the drill motor begins to slow down from the peak amplitude 42 to the trough amplitude 44 of the waveform 50. Therefore, provided the drill 10 is capable of driving the drill bit within the recommended range of drilling speed, the drill bit should be driven at least at two points within each period such that the drilling speed will be optimal for the diameter which is in the process of drilling.

[0050]By automatically varying the frequency of the speed of the drill according to the waveform 50, the present invention has proven effective in the drilling of at least steel, wood, hard rock and/or masonry and for screwing of self-tapping screws. As mentioned above, the varying of the frequency according to the material being drilled provides the drill bit to cut the material across the radius of a cutting edge of the drill bit in an efficient manner. Efficient manner means the drill bit was cutting at an optimal drilling speed when engaged with the workpiece at the drill bit diameter which the optimal drilling speed applies. The frequency is selected based on the opportunity that it provides for the material being drilled and the size of the drill bit.

[0051]The frequency for the material being drilled is selected such that the bit rotates at a speed substantially optimised for a radial point on the cutting edge for long enough to cut the material at that radius before the speed changes to be substantially optimised for a different radial position on the cutting edge as the hole is drilled in the workpiece. Depending on the type of material if the rate of change of speed is too slow (frequency too low) the optimal speed for part of the cutting the bit is at may not be reaches quickly enough thus reducing the efficiency of the drilling. Also, depending on the type of material if the rate of change of speed is too fast (frequency too high) the optimal speed for part of the cutting the bit is at may be reached and passed by too quickly not allowing it to be at the optimal speed for long enough, thus reducing the efficiency of the drilling. Thus, there will be an optimal rate of change of speed (frequency of the waveform) at which the optimal speed will be reached quickly and also not passed by too quickly for each type of material for a given size of drill bit.

[0052]In order to vary the speed of the drill 10, the voltage supplied to the drill motor is varied during operation of the drill 10 between a maximum voltage and a minimum voltage. The maximum voltage will be limited by a capacity of the drill 10. As discussed above, the minimum voltage may be zero. However, in some circumstances, to prevent stalling of the drill bit, the minimum voltage is offset from zero. Preferably, the voltage is offset from zero such that the when the speed of the drill is varied to the minimum voltage, the drill bit is still rotating.

[0053]The present invention is configured to provide the maximum power to the drill motor when varying the speed of the drill motor according to the peaks of the waveform. Conversely, the present invention is configured to provide the minimum power when varying the speed of the drill motor to the troughs of the waveform.

[0054]In the present embodiment, there is provided a controller in the form of the motor controller module 30 which comprises the microcontroller and a motor speed controller. The microcontroller comprises a processor which produces the signal according to the inputs 20 provided at the control panel. The signal automatically varies according to a waveform 50, which is preferably a sinusoidal waveform 52. In the present embodiment, the microcontroller outputs a signal using pulse width modulation which the motor speed controller receives as an input and decodes as a signal to be output. The signal being output by the microcontroller using pulse width modulation is varied according to the waveform 50. The motor speed controller of the motor controller module 30 outputs the signal for controlling a speed of rotation of the drill motor. The signal comprises at least a voltage. The voltage is varied according to the waveform 50. The voltage drives the drill motor which in turn drives the bit. The characteristics of the waveform are determined by the material by at least the material to be drilled and/or the diameter of the drill bit. The characteristics of the waveform can be varied so as to account at least for imperfections in the material to be drilled and uncertainty in the material being drilled.

[0055]The inputs available for the user to select to vary the waveform 50 which the drill motor is automatically varied according to comprise one or more of amplitude, frequency and/or offset. For example, referring to Figures 5 and 6 there is provided different speed curves 40 of the drill motor. The speed curve 40 of Figure 4 shows the amplitude of the speed of the drill motor being varied. The speed curve 40 of Figure 5 shows the frequency of the speed of the drill motor being varied. In Figure 5, there is provided a time wherein the motor speed drops to zero. This occurs when the trigger of the drill 10 has been released, when the trigger of the drill 10 is actuated again the drill ramps up quickly to start from the lowest speed according to the waveform 50, whether zero or offset from zero, and after reaching that speed build up and conform to the waveform 50 until the trigger of the drill 50 is released.

[0056]The motor controller module 30 stores a computer program for controlling the speed of rotation of a motor of the drill 10. The computer program comprises instructions for execution by a processor which causes the motor of the drill 10 to be controlled such that a speed of rotation of the motor is automatically varied according to a waveform, wherein one of more characteristics of the waveform is determined by a material to be drilled and/or a diameter of the bit.

[0057]In an embodiment, the computer program comprising computer executable instructions stored in a non-transient manner for controlling a processor of a drill to perform one or more of the methods defined below.

[0058] Referring to Figure 6 there is provided a circuit diagram of an embodiment of the invention comprising the drill 10, the inputs 20 and the motor controller module 30. The circuit diagram provided is intended to be one of many ways of implementing the invention and should not be construed as limiting on the invention. Additional components and/or features may be implemented where the person skilled the art would be inclined to do so.

[0059] Modifications may be made to the present invention within the context of that described and shown in the drawings. Such modifications are intended to form part of the invention described in this specification.

Claims

1. A drill comprising: a controller configured to automatically vary a speed of rotation of a bit according to a waveform having a characteristic selected according to a material being drilled and/or a diameter of the bit.

2. A controller for controlling a motor of a drill comprising:

an output of a signal for controlling a speed of rotation of the motor,

3. A computer program for controlling the speed of rotation of a motor of a drill, the computer program comprising:

4. A method of controlling the speed of rotation of a drill comprising:

5. A method of drilling comprising:

6. A drill comprising: a controller configured to automatically vary a speed of rotation of a bit according to a waveform having a frequency selected according to a material being drilled.

7. A drill comprising:

- 1/4 - 25 Aug 2021

20 INPUTS 2021107344

30 MOTOR CONTROLLER MODULE

10

DRILL

FIGURE 1

Drill Motor Speed (in RPM)

44 42 - 2/4 -

FIGURE 2 TIME (in ms) 42

46

- 3/4 - 25 Aug 2021

50

52 2021107344

54

56

FIGURE 3

40

Figure 4 40 40

Figure 5

- 4/4 - 25 Aug 2021 2021107344

20

30

10

FIGURE 6