Machine and method for operating machine

Abstract

A machine and method for drilling or inserting a screw wherein the machine includes a motor having a shaft, and a controller, the controller is configured to provide an electric current to the motor to rotationally drive the shaft, continuously determine a set of parameters characterizing a drilling and / or implantation process, identify a parameter condition of each parameter of the set of parameters as a constant if a variation of the parameter over time is below a threshold value, and determine a parameter condition of each parameter of the set of parameters as a constant if a variation of the parameter over time is below a threshold value. Identifying a parameter condition of each parameter of the set of parameters as a variable if a variation of the parameter over time is above a threshold value, continuously determining a number of parameters whose parameter conditions are changing, and stopping the motor if the number is at least a predetermined minimum number within a predetermined time interval.

Description

Technical Field

[0001] Machines and methods for operating the machines to drill holes (e.g., pilot holes) and / or set screws are described herein. Handheld power tools for performing the drilling and / or screw setting actions are also described. Typically, such handheld tools are widely used in the construction industry. Typical handheld tools intended to be included within the scope of the present invention include, but are not limited to, automatic screwdrivers for screwing screw fasteners into workpieces, thereby causing the screw fasteners to penetrate the workpieces, such as metal sheets. Background Art

[0002] Hand-held power tools are known that can perform a screw driving action. These tools include at least one machine housing that includes at least one motor that provides at least a rotational motion to a rotating shaft. The rotating shaft in turn ultimately transmits a certain torque at a certain rotational speed to a workpiece penetrating element, such as a drill bit or a screw fastener. The tool may also include a controller for controlling the motor and continuously determining several parameters of the drilling or driving process, such as the torque and rotational speed transmitted by the rotating shaft when the tool is in use.

[0003] One possible area of ​​application is the use of step drills to drill pilot holes, for example in preparation for self-drilling and self-sealing threaded fasteners. This type of work is usually done by professional construction workers who are accustomed to pressing the step drill against the substructure with great force and for a long time to ensure that the pilot hole has sufficient depth. Due to this high force and long time, the shape of the pilot hole may become imprecise. Summary of the invention

[0004] According to one aspect, a method for operating a machine to drill a hole in a workpiece and / or drive a screw into a workpiece along an insertion axis, wherein the machine includes a motor having a shaft, the method comprising: providing current to the motor to rotationally drive the shaft, continuously determining a set of parameters characterizing the drilling and / or insertion process, identifying a parameter condition of each parameter in the set of parameters as a constant if the change in the parameter over time is below a threshold, identifying a parameter condition of each parameter in the set of parameters as a variable if the change in the parameter over time is above a threshold, continuously determining the number of parameters whose parameter conditions are changing, and stopping the motor if the number is at least a predetermined minimum number within a predetermined time interval. The predetermined minimum number can be two, three, four, five, or more. The predetermined time interval can be one second, a fraction of a second, or zero.

[0005] According to another aspect, a machine for drilling a hole in a workpiece and / or driving a screw into a workpiece along an insertion axis, the machine comprising a motor having a shaft, a switch, and a controller configured to provide current to the motor to rotationally drive the shaft, continuously determine a set of parameters characterizing the drilling and / or insertion process, identify the parameter condition of each parameter in the set of parameters as a constant if the change in the parameter over time is below a threshold, identify the parameter condition of each parameter in the set of parameters as a variable if the change in the parameter over time is above a threshold, continuously determine the number of parameters whose parameter conditions are changing, and stop the motor if the number is at least a predetermined minimum number within a predetermined time interval. The predetermined minimum number can be two, three, four, five, or more. The predetermined time interval can be one second, a fraction of a second, or zero.

[0006] According to one embodiment, the set of parameters includes at least one of the following: the force applied to the machine along the insertion axis, the torque applied to the shaft about the insertion axis, the voltage of the current supplied to the motor, the amperage of the current supplied to the motor, the rotation speed of the motor, the acceleration of the machine along the insertion axis, the acceleration of the machine across the insertion axis, the rotation of the machine about the insertion axis, and the yaw rate of the machine, that is, the rotation of the machine about an axis perpendicular to the insertion axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Further aspects and advantages of the machine, associated parts, and methods of use thereof will become more apparent from the following description given by way of example only and with reference to the accompanying drawings, in which: Figure 1 A machine for drilling holes and inserting screws is shown. DETAILED DESCRIPTION

[0008] Figure 1 A machine 100 for drilling and / or inserting screws is shown. In the embodiment shown, the machine 100 is formed as a handheld working tool, such as an automatic screwdriver. The machine 100 comprises a housing 105 and a motor 110 with a shaft 120 enclosed by the housing 105, a switch 130 formed as a trigger switch, a controller 140 formed as a microcomputer and having a data storage device 145 formed as a computer memory, a battery 150, and a communication unit 155 formed as a wireless transmitter. The controller 140 provides current from the battery 150 to the motor 110 to rotationally drive the shaft 120. The machine 100 further comprises a gear 160 and a spindle 170, which has a screw drive 175, such as a hexagonal drive, and is driven by the shaft 120 via the gear 160.

[0009] In addition, the machine 100 includes a rotation speed sensor 180 for detecting the rotation speed of the motor 110, and an ampere / voltage sensor 190 for detecting the ampere and / or voltage of the current supplied to the motor 110. In addition, the machine 100 includes a plurality of acceleration sensors for detecting the force applied to the shaft of the machine along the set-in axis, the acceleration of the machine along the set-in axis, the acceleration of the machine across the set-in axis, the rotation of the machine about the set-in axis, and the yaw rate of the machine, i.e., the rotation of the machine about an axis perpendicular to the set-in axis.

[0010] Furthermore, the machine 100 comprises a line 195 connecting the controller 140 with the motor 110, the switch 130 and the sensors 180, 190 to transmit current to the motor 110 and / or collect electrical signals from the switch 130 and / or the sensors 180, 190. Additionally or alternatively, in order to obtain data on the rotational speed, amperage or voltage of the motor 110, the controller 140 can use information already present in its control of the rotational movement of the motor 110, such as the variation over time of the number of electrical commutations for the rotational speed. The housing 105 comprises a gripping section 106 for manual gripping of the machine 100 by a user so that the user's index finger can press the switch 130. The switch 130 can signal its switch position to the controller 140 via the line 195.

[0011] The controller 140 continuously determines a set of parameters that characterize the drilling and / or placement process, such as the force applied to the machine along the placement axis, the torque applied to the shaft about the placement axis, the voltage of the current supplied to the motor, the amperage of the current supplied to the motor, the speed of the motor, the acceleration of the machine along the placement axis, the acceleration of the machine across the placement axis, the rotation of the machine about the placement axis, or the yaw rate of the machine.

[0012] In use, the machine 100 can be set up by selecting the correct clutch setting and gear, so that, for example, a drilling mode is activated. During the drilling process, the controller 140 monitors the above parameters, such as the motor current, and possibly the acceleration and yaw rate in all directions. The controller 140 identifies the parameter condition of each parameter in the set of parameters as a constant if the change of the parameter over time is below a threshold, or identifies the parameter condition of each parameter in the set of parameters as a variable if the change of the parameter over time is above a threshold. To this end, for each monitored parameter, two signals are derived by using appropriate filters. Thus, the first signal shows a long-term value (e.g., a current of 10 A as the average current for the last 3 seconds of the drilling process). The second signal shows a shorter-term value (e.g., the average current for the last 30 ms of the drilling process). If the two signals obtained differ from each other by more than a defined threshold, the condition count of the end of drilling is increased by one. The controller 140 continuously determines the number of parameters whose parameter conditions are changing, and if this number is at least two, three, four or five within a predetermined time interval, the motor is automatically stopped after a waiting time of a fraction of a second. In an alternative embodiment, the wait time is zero.

[0013] In summary, when the step of the drill bit hits the surface of the substructure, some parameters characterizing the drilling process change (e.g., acceleration, motor current). The controller 140 recognizes the change and stops the tool. The drilling process is reliably stopped at an earlier point in the process, thereby saving time, producing a more accurate pilot hole shape, or preventing unnecessary wear.

[0014] Throughout this application, "the current supplied to the motor" is meant to include the current measured within the power source (eg, a battery if the handheld power tool is a battery operated tool).

[0015] The above description of exemplary embodiments of the present invention has been presented for the purpose of showing and illustrating. It is not intended to exhaust the present invention or to limit the present invention to the precise form disclosed, and modifications and variations are possible according to the above teachings, or modifications and variations can be obtained from the practice of the present invention. The functions described may be distributed between modules that are different from the functions described herein in terms of the number and distribution of functions. In addition, the order in which the functions are performed may be changed according to the embodiment. The embodiments are selected and described in order to explain the principles of the present invention and to enable those skilled in the art to utilize the present invention in various embodiments with various modifications suitable for the specific purpose envisioned as a practical application of the present invention. The scope of the present invention is intended to be limited by the appended claims and their equivalents.

Claims

1. A method for operating a machine for drilling a hole in a workpiece and / or for driving a screw into a workpiece along an axis of insertion, wherein: The machine includes a motor having a shaft, the method comprising: - supplying electric current to the motor to rotationally drive the shaft; - continuously determining a set of parameters characterizing the drilling and / or insertion process; - identifying a parameter condition for each parameter in the set of parameters as constant if the change in that parameter over time is below a threshold; - identifying the parameter condition for each parameter in the set of parameters as a variable if the change in the parameter over time is above the threshold; - continuously determine the number of parameters whose parameter conditions are changing; - If the number is at least a predetermined minimum number within a predetermined time interval, the motor is stopped.

2. The method according to claim 1, wherein: The set of parameters includes at least one of the following: a force applied to the machine along the inserted axis, a torque applied to the shaft about the inserted axis, a voltage of the current supplied to the motor, an amperage of the current supplied to the motor, a rotation speed of the motor, an acceleration of the machine along the inserted axis, an acceleration of the machine across the inserted axis, a rotation of the machine about the inserted axis, and a yaw rate of the machine.

3. The method according to any one of claims 1 and 2, wherein: The minimum quantity for this reservation is two.

4. The method according to any one of claims 1 and 2, wherein: The minimum number for this reservation is three.

5. The method according to any one of claims 1 and 2, wherein: The minimum number for this reservation is four.

6. The method according to any one of claims 1 and 2, wherein: The minimum number of reservations is five or more.

7. A method according to any one of the preceding claims, wherein: The predetermined time interval is zero.

8. A machine for drilling a hole in a workpiece and / or driving a screw into a workpiece along an axis of insertion, the machine comprising: - a motor having a shaft; - switch; - A controller configured to provide current to the motor to rotationally drive the shaft, continuously determine a set of parameters characterizing a drilling and / or placement process, identify a parameter condition of each parameter in the set of parameters as a constant if the change in the parameter over time is below a threshold, identify a parameter condition of each parameter in the set of parameters as a variable if the change in the parameter over time is above the threshold, continuously determine a number of parameters whose parameter conditions are changing, and stop the motor if the number is at least a predetermined minimum number within a predetermined time interval.

9. The machine according to claim 8, wherein: The set of parameters includes at least one of the following: a force applied to the machine along the inserted axis, a torque applied to the shaft about the inserted axis, a voltage of the current supplied to the motor, an amperage of the current supplied to the motor, a rotation speed of the motor, an acceleration of the machine along the inserted axis, an acceleration of the machine across the inserted axis, a rotation of the machine about the inserted axis, and a yaw rate of the machine.

10. The machine according to any one of claims 8 and 9, wherein The minimum quantity for this reservation is two.

11. The machine according to any one of claims 8 and 9, wherein: The minimum number for this reservation is three.

12. The machine according to any one of claims 8 and 9, wherein: The minimum number for this reservation is four.

13. The machine according to any one of claims 8 and 9, wherein: The minimum number of reservations is five or more.

14. The method according to any one of claims 8 to 13, wherein: The predetermined time interval is zero.

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