Chain saw having a measurement system and method for operating a chain saw

Abstract

A motorized chain saw has a measuring system for measuring an object, in particular a trunk. The motorized chain saw has a saw chain, and the measuring system has an evaluation device. The measuring system includes a sensor system for capturing the movement of the saw chain as the saw chain rolls over an object to be measured. The evaluation device is configured to evaluate the movement of the saw chain captured by the sensor system. In a method for operating the motorized chain saw, the sensor system captures the movement of the saw chain as the saw chain rolls over an object to be measured, and the evaluation device evaluates the captured movement.

Claims

1. A chain saw comprising: a saw chain; a measurement system including an evaluation device; said measurement system being configured to measure an object to be measured via said saw chain rolling over the object to be measured; said measurement system having sensors for capturing a movement of said saw chain as said saw chain rolls over the object to be measured; and, said evaluation device being designed to evaluate the movement of the saw chain captured by the sensors.

2. The chain saw of claim 1 further comprising a display element for indicating a captured dimension (a) of the object.

3. The chain saw of claim 1 further comprising: a drive sprocket for said saw chain; and, said sensors being configured to detect the movement of said saw chain adjacent to said drive sprocket.

4. The chain saw of claim 1 further comprising: a housing; and, said sensors and said evaluation device being arranged in said housing.

5. The chain saw of claim 4, wherein said housing includes a sprocket wheel cover; and, said sensors are arranged beneath the sprocket wheel cover.

6. The chain saw of claim 1, wherein said saw chain has chain links; and, said chain links serve as pulse generators for said sensors.

7. The chain saw of claim 1 further comprising: a clutch having a power takeoff side; a drive motor configured to drive said saw chain via said clutch; and, said measurement system being configured to detect the movement of said saw chain at said power takeoff side of said clutch.

8. The chain saw of claim 1, wherein: said evaluation device includes a microcontroller; the movement of said saw chain is a rotary movement; and, said microcontroller is configured to evaluate the rotary movement of said saw chain captured by said sensors.

9. A method for operating a chain saw with a measurement system, wherein the chain saw includes a saw chain, the measurement system includes an evaluation device, the measurement system being configured to measure an object to be measured via the saw chain rolling over the object to be measured, the measurement system including sensors for capturing a movement of the saw chain as the saw chain rolls over the object to be measured, and the evaluation device being configured to evaluate the movement captured by the sensors, the method comprising the steps of: capturing a movement of the saw chain as the saw chain rolls over an object to be measured via the sensors; and, evaluating the captured movement via the evaluation device.

10. The method of claim 9, further comprising the step of determining via the evaluation device a dimension (a) of the object over which the saw chain rolls from the captured movement.

11. The method of claim 10 further comprising indicating the dimension (a) determined by the evaluation device on a display element.

12. The method of claim 11, wherein the chain saw includes the display element.

13. The method of claim 10, wherein the measurement system resets the captured dimension (a) to zero upon exceeding a predetermined speed of the saw chain.

14. The method of claim 10 further comprising the step of resetting the captured dimension (a) to zero upon exceeding a predetermined speed of the saw chain.

15. The method of claim 10, wherein: the measurement system has an active state and an inactive state; the measurement system is configured to detect, evaluate, and/or indicate the dimension (a) rolled over by the saw chain only in the active state; and, the measurement system is switched from the active state to the inactive state in dependence upon the speed of the saw chain.

16. The method of claim 9 further comprising: detecting a movement direction of the saw chain via the sensors; and, wherein the evaluation device increases a measured value for a movement of the saw chain in a first movement direction and decreases it for a movement in a second, opposite movement direction.

17. The method of claim 9, wherein the saw chain includes a plurality of chain links and the chain links serve as pulse generators for the sensors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described with reference to the drawings wherein:

(2) FIG. 1 is a schematic side view of a chain saw; and,

(3) FIG. 2 is a schematic side view of a chain saw while measuring an object to be measured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(4) The chain saw 1 shown schematically in FIG. 1 has a saw chain 2 and a measurement system 3. The measurement system 3 includes an evaluation device, in the sample embodiment a microcontroller 8, which detects a movement 6 of the saw chain 2. The measurement system 3 furthermore includes a display element 4. The display element 4 is arranged in the upper region of the chain saw 1 on the side of the chain saw 1 facing away from the saw chain 2. In this way, the display element 4 can be well seen by the user standing behind the chain saw 1 or next to the chain saw 1.

(5) The chain saw 1 is configured to measure the path traveled by the chain saw 1 with the saw chain 2 along an object being measured, such as a trunk, and to indicate this on the display element 4. For this, a user must roll the saw chain 2 over a trunk being measured or some other object being measured. The rotary movement 6 of the saw chain 2 is detected via sensors and evaluated at least partly by the microcontroller 8. The evaluated dimensions are indicated on the display element 4.

(6) FIG. 2 shows the arrangement in detail. The chain saw 1 has a housing 24, on which are fastened a rear handle 10 and a bale handle 13 for guiding the chain saw 1 during its operation. On the rear handle 10 are pivotably mounted a throttle lever 11 and a throttle lever lock 12. The throttle lever 11 serves for actuating a drive motor 14 arranged in the housing 24. In the sample embodiment, the drive motor 14 is shown schematically as an internal combustion engine. However, the drive motor 14 may also be an electric motor. A guide bar 23 is secured to the housing 24 and the saw chain 2 is led along its outer circumference. The drive motor 14 drives a drive sprocket 15 across a centrifugal clutch 16, into which the saw chain 2 engages. The saw chain 2 is indicated schematically in FIG. 2. The centrifugal clutch 16 includes a clutch drum 17, on which the drive sprocket 15 is arranged. The clutch drum 17 and the drive sprocket 15 are situated at the power takeoff end of the clutch 16. As long as the speed of the drive motor stays below the clutch engaging speed of the centrifugal clutch 16, the drive sprocket 15 will not be turned by the drive motor 1.

(7) The saw chain 2 includes connecting links 19 and drive links 22, which are articulated to each other. The connecting links 19 are partly fashioned as cutting links 18. The cutting links 18 each have a cutting tooth 20 and a depth limiter 21 situated in front of the cutting tooth 20. The depth limiter 21 is situated in front of the cutting tooth 20 in terms of the running direction of the saw chain 2, corresponding to the movement 6. The guide bar 23 has a tip 32, being the end of the guide bar 23 which is distant from the housing 24. The movement 6 of the saw chain 2 is a movement running around the guide bar 23, that is, a rotary movement, wherein the saw chain 2 moves in opposite directions along the opposite lengthwise sides of the guide bar 23.

(8) For the measuring off of an object to be cut to length, such as a trunk 26 as shown schematically in FIG. 2, the chain saw 1 has the measurement system 3, including the sensors 7 and an evaluation device, namely, the microcontroller 8. Several evaluation devices, each one performing part of the evaluation, may also be advantageous. The display element 4 is also advantageously part of the measurement system 3. The measurement system 3 advantageously includes a power supply 33, especially a battery or a storage cell. Through the power supply 33, the measurement system 3 is supplied with energy when the drive motor 14 is not running. The chain saw 1 has a sprocket wheel cover 25, which is part of the housing 24. The guide bar 23 is held clamped by the sprocket wheel cover 25. The sensors 7 and the microcontroller 8 as well as the power supply 33 are arranged in the housing 24 beneath the sprocket wheel cover 25. The sensors 7 are preferably situated adjacent to the outer circumference of the drive sprocket 15. The sensors 7 are advantageously arranged such that the chain links of the saw chain 2 move past the sensors at slight distance during a rotary movement 6 of the saw chain 2. The microcontroller 8 may be situated adjacent to the sensors 7, be situated in a housing with the sensors 7, or be situated at a distance from the sensors 7. The microcontroller 8 may also be a microcontroller which is also provided for the control of the drive motor 14. The power supply 33 may likewise be arranged integrated in a housing with the sensors 7 and/or the microcontroller 8, or separate from them.

(9) It may also be provided that the microcontroller 8 is arranged outside the chain saw 1. In particular, the microcontroller 8 is the microcontroller 8 of a computing unit 35, as shown schematically by broken line in FIG. 2. The sensors 7 preferably relay to the computing unit 35 signals corresponding to the pulses generated by the saw chain 2 at the sensors 7 and which are evaluated by the computing unit 35 and converted into a dimension over which the saw chain 2 has been rolled. In an embodiment, the computing unit 35 also includes the display element 4, as represented schematically by broken line in FIG. 2.

(10) For the measuring off of an object being cut to length, such as the trunk 26, it is provided that the user places the chain saw 1 by the free end of the guide bar 23, preferably in the region of the tip 32 of the guide bar 23, against the trunk 26 and moves along the trunk 26. In the sample embodiment, a start point 30 and an end point 31 for the measurement are provided. The saw chain 2 is moved from the start point 30 to the end point 31 along the trunk 26 and in this process rolls over the trunk 26. The chain saw 1 is led in a movement direction 27 from the start point 30 to the end point 31 along the trunk 26. The sensors 7 detect the movement 6 of the saw chain 2 generated by the rolling along the trunk 26. During the movement of the chain saw 1 along the trunk 26, the chain links and especially the cutting teeth 20 of the cutting links 18 advantageously catch the trunk 26 and prevent the saw chain 2 from sliding along the trunk 26. The movement 6 is detected by the sensors 7. The microcontroller 8 evaluates the signal detected by the sensors 7 at least in part. In particular, the chain links serve as signal generators for the sensors 7, namely the connecting links 19, which also include the cutting links 18, and/or the drive links 22. The detection of the movement 6 may be done optically, electrically or mechanically, for example. It may also be provided that the sensors 7 detect the movement 6, namely, the rotary movement of the drive sprocket 15 or the clutch drum 17. The microcontroller advantageously determines from the movement 6 of the saw chain 2 the dimension a which corresponds to the distance between the start point 30 and the end point 31, that is, the length of the object being measured, namely, a segment of the trunk 26. The dimension a calculated by the microcontroller 8 is indicated on the display element 4. Advantageously, the detection, evaluation and indication occur in an ongoing manner during the entire measurement, so that the distance from the start point 30 is indicated to the user at every point traveled along the trunk 26. Alternatively, it may be provided that the user enters a desired dimension, for example on the computing unit 35, and the evaluation device subtracts the dimension already rolled over from the desired dimension and continuously displays the remaining residual length. The reaching of the desired dimension can be displayed to the user preferably optically and/or acoustically.

(11) If the chain saw 1 is moved in the movement direction 27, the saw chain 2 will turn in a first movement direction 28. If the user moves the chain saw 1 too far and the indicated dimension a is greater than the desired dimension, for example, the user can advantageously move the chain saw 1 back in a direction opposite the movement direction 27. In this way, the saw chain 2 moves in a second movement direction 29, which is opposite the first movement direction 28. The sensors 7 advantageously detect not only the movement of the saw chain 2, that is, the length of the saw chain 2 having moved past the sensors 7, but also the movement direction 28 or 29 of the saw chain 2. If the saw chain 2 is moving in the first movement direction 28, corresponding to a movement of the chain saw 1 from the start point 30 toward the end point 31, the microcontroller 8 will increase the measured value a each time by the length of the saw chain 2 having moved past the sensors 7. If the chain saw 1 is moved in the opposite direction, so that the saw chain 2 is moving in the second movement direction 29, the microcontroller 8 will advantageously decrease the dimension a by the length of the saw chain 2 having moved past the sensors 7 in the second movement direction 29. In this way, a correction of the dimension a by the user is easily possible. Advantageously, the display element 4 continuously indicates during the measurement process the current dimension a, already traveled, or the current dimension yet to be traveled.

(12) The measurement system 3 advantageously has an active state, in which the display element 4 indicates a dimension a and detects and evaluates the movement 6, and an inactive state in which no dimension a is indicated. In the inactive state, it may be provided that the measurement system 3 does not detect the movement 6 of the saw chain 2 or the microcontroller 7 does not evaluate a movement 6 detected. It may be provided that the measurement system 3 is switched by the user between the active and the inactive state, for example, by activating an operator element. However, it is preferably provided that the measurement system 3 is switched from the active state to the inactive state depending on the speed of the saw chain 2. Advantageously, the measurement system 3 is then switched to the inactive state not later than when the speed of the drive sprocket 15 lies above the clutch engaging speed of the centrifugal clutch 16 and the drive sprocket 15 is driven by the drive motor 14.

(13) In order to mark a dimension a of a trunk 26 that has been measured off, the user can move the chain saw 2 in a rapid movement along the trunk 26 and thereby inscribe and thus mark the trunk 26. During this movement, the speed of the saw chain 2 increases abruptly. Advantageously, the speed increase is utilized to reset the measurement system 3, that is, to set the dimension a to zero. Advantageously, a resetting of the dimension a occurs as soon as the speed of the saw chain 2 exceeds a given speed threshold, corresponding in particular to the speed when inscribing a trunk 26.

(14) It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.