WO2012019343A1

WO2012019343A1 - Circular saw with control accessory

Info

Publication number: WO2012019343A1
Application number: PCT/CN2010/075889
Authority: WO
Inventors: Jizhong Fu; Aigui Wang; Songtao Jin; Jiahao Fan; Sheng Lai; Ruilin Ke
Original assignee: Bosch Power Tools China Co Ltd
Current assignee: Bosch Power Tools China Co Ltd
Priority date: 2010-08-11
Filing date: 2010-08-11
Publication date: 2012-02-16
Anticipated expiration: 2013-02-11
Also published as: DE112010005801T5; CN103068510B; CN103068510A

Abstract

A circular saw comprises a saw blade, a motor for driving the saw blade, and a control accessory for pre-setting, measuring, displaying and controlling the cutting parameters of the circular saw.

Description

Circular Saw with Control Accessory

Technical Field

The invention relates to a circular saw having an improved control accessory for pre-setting, measuring, displaying and controlling the cutting parameters of the circular saw.

Background Art

Cutting a workpiece with a circular saw is well known. Most of the available circular saws cannot measure and display cutting length in real time. Thus, a user cannot know exact cutting length.

Some circular saws are equipped with external accessories or fixtures for measuring the cutting length of each single cut. However, this solution is not convenient in operation. Meanwhile, information obtained by such an external measuring accessory or fixture is not enough.

For example, it may be desired to know the total cutting distance for the service of the saw, such as exchanging a saw blade. In addition, current cutting speed is also an important parameter need to know.

Thus, there is a need for a circular saw with an improved control accessory which can be used to pre-set, measure, display and control desired cutting parameters of the circular saw.

Summary of the Invention

In view of the above need existed in the art, an object of the invention is to provide a circular saw with an improved control accessory.

For achieving this object, in one aspect, the present invention provides a circular saw comprising:

a saw blade;

a motor for driving the saw blade; and

a control accessory for pre-setting, measuring, displaying and controlling the cutting parameters of the circular saw.

In accordance with a preferred embodiment of the invention, the control accessory comprises:

a CPU having a timer and an arithmometer; and a trigger, a distance sensor and a display, all connected with the CPU;

wherein the trigger is configured to be activated by a user to start the cutting motion of the saw blade;

the distance sensor is configured to measure the cutting length of the saw and send pulse signals to the CPU; and

the display is configured to indicate the cutting parameters of the circular saw.

In accordance with another preferred embodiment of the invention, the trigger is a mechanical trigger or an electrical trigger.

In accordance with another preferred embodiment of the invention, the distance sensor is a contact sensor or a non-contact sensor.

In accordance with another preferred embodiment of the invention, the distance sensor is an optoelectronic distance sensor, an ultrasonic distance sensor, or a laser distance sensor.

In accordance with another preferred embodiment of the invention, the control accessory further comprises a power supply control unit which is connected between the CPU and a power supply of the motor of the saw so as to switch off the power supply according to the command from the CPU.

In accordance with another preferred embodiment of the invention, the control accessory further comprises a key board which is a man-machine interface for pre-setting operation parameters of the circular saw and loading former operation parameters stored in the CPU.

In accordance with another preferred embodiment of the invention, the control accessory further comprises an alarm for indicating the end or a malfunction of the cutting operation of the saw.

In accordance with another preferred embodiment of the invention, the alarm is an audio and/or video alarm.

In accordance with another preferred embodiment of the invention, the cutting operation of the circular saw comprises the following steps:

Step SI , in which the cutting parameters of the circular saw are input by means of the key board or loaded from the data stored in the CPU;

Step S2, in which the saw is switched on, and the trigger is actuated so that the saw blade starts to cut into a workpiece;

Step S3, in which the distance sensor sends impulse signals to the CPU, and at the meantime, the timer and the arithmometer start to work; Step S4, in which the CPU processes the impulse signals to determine current cutting length;

Step S5, in which related data are displayed by the display;

Step S6, in which the CPU judges whether the current cutting length reaches the target cutting length; if the judge result of Step S6 is "No", then the operation goes back to Step S4; if the judge result of Step S6 is "Yes", then the operation goes forwards to Step S7;

Step S7, in which the alarm is activated to indicate the end of the cutting operation; and

Step S8, in which the saw is switched off manually or switched off automatically by the power supply control unit under the command from the CPU.

In accordance with another preferred embodiment of the invention, the cutting parameters of the circular saw include at least one of:

1) total cutting distance;

2) current single cutting length;

3) target length;

4) cutting speed; and

5) Date and time.

In accordance with another preferred embodiment of the invention, the control accessory further comprises an over-heat or over-current protect unit which is connected to the CPU for sensing the temperature of the motor or electrical current supplied to the motor; wherein the CPU disconnects the power supply to the motor when the temperature of the motor is higher than a threshold temperature or the electrical current becomes higher than a threshold current for a period of time.

In accordance with another preferred embodiment of the invention, the control accessory further comprises means for sensing and controlling the tilt angle of the saw blade as a cutting parameter of the circular saw.

In accordance with another preferred embodiment of the invention, the control accessory further comprises means for sensing and controlling the cutting depth of the saw blade cutting into the workpiece as a cutting parameter of the circular saw.

In accordance with another preferred embodiment of the invention, the control accessory further comprises computer connection port.

In accordance with another preferred embodiment of the invention, the CPU disconnects the power supply to the motor when the cutting speed and/or the rotational speed of the saw blade become lower than corresponding predetermined values.

In accordance with another preferred embodiment of the invention, the circular saw is a table circular saw or a portable circular saw.

In accordance with another preferred embodiment of the invention, the circular saw is configured for cutting wood, plastic materials, metals, or composite materials.

According to the invention, by providing a new control accessory for a circular saw, the cutting status or parameters, such as cutting distance and cutting speed, can be shown synchronously. In addition, the end user can preset cutting parameters such as target cutting length and cutting speed. Moreover, an alarm is activated when it reaches the target cutting length or there is malfunction, and then the cutting operation can be stopped automatically.

Brief Description of the Drawings

The invention will be further understood by reading the following detailed description with reference to the drawings in which:

Fig. 1 is a schematic block diagram of an control accessory for a circular saw according to an embodiment of the invention; and

Fig. 2 is a flow chart of the operation of the control accessory.

Detailed Description of Preferred Embodiments

Now a circular saw according to a preferred embodiment of the invention will be described with reference to Fig. 1.

The circular saw of the invention comprises a control accessory for setting, measuring, displaying and controlling various cutting parameters of the circular saw, such as current and total cutting lengths, cutting speed, and the like.

As shown in Fig. 1, the control accessory comprises:

a CPU 1 ; and

a trigger 2, a distance sensor 3, a display 4, a power supply control unit 5, a key board 6, an alarm 7, and the like, which are all connected with the CPU 1.

The CPU 1 is a single chip element for receiving information from / sending commands to other components. The CPU 1 has a calculagraph or timer and an arithmometer.

The trigger 2 may be a mechanical trigger or an electrical trigger and is activated by a user to start the cutting movement of the saw blade and at the same time activate the distance sensor 1.

The distance sensor 3 may be a contact sensor or a non-contact sensor for measuring the cutting length of the saw and sends pulse signal to the CPU 1. The distance sensor may use any type of sensors known in the art, for example, an optoelectronic distance sensor, an ultrasonic distance sensor, a laser distance sensor, or the like.

The display 4 may display input and output data and operation parameters of the saw.

The power supply control unit 5 is connected between the CPU 1 and the power supply of the motor of the saw so as to switch off the power supply according to the command from the CPU 1.

The key board 6 is a man-machine interface for the user to input pre- setting operation parameters and load former operation parameters stored in the CPU 1.

The alarm 7 may be an audio and/or video alarm which indicates the end or malfunction of the cutting operation of the saw. For example, the audio alarm may output beep sound or a human voice indicating the current condition of the operation. The video alarm may be a coloured flash, indicating symbols or words, or the like.

Now the operation of the circular saw will be described with reference to Fig. 2.

As shown in Fig. 2, in Step SI, a user presets cutting parameters of the circular saw, such as target cutting length, cutting speed, and the like. If the next cutting is the same as the former one, former cutting parameters are loaded automatically by the CPU 1 and no new cutting parameters are input.

Then, in Step S2, the saw is switched on, and the trigger is actuated by the user, so that the saw blade begins to cut into a workpiece.

Then, in Step S3, the distance sensor sends impulse signals to the CPU 1. At the meantime, the calculagraph and the arithmometer start to work.

Then, in Step S4, the CPU 1 processes the impulse signals to determine current cutting length.

Then, in Step S5, related data are displayed on the screen of the display 4. The related data may include:

1) Total cutting distance;

2) Current single cutting length; 3) Target length;

4) Cutting speed; and

5) Other desired data.

Then, in Step S6, the CPU 1 judges whether the current cutting length reaches the target cutting length. If the judge result of Step S6 is "No", then the operation goes back to Step S4. If the judge result of Step S6 is "Yes", then the operation goes forwards to Step S7.

In Step S7, the alarm 7 is activated to output an audio and/or video alarm which indicates the end of the cutting operation.

Then, in Step S8, the saw is switched off manually by the user or automatically by the power supply control unit 5 under the command from the CPU 1.

According to the invention, all the related data will be shown on the display 4 in real time.

The control accessory is powered by a low voltage DC supply which is dependent or independent of the power supply of the saw.

After the cutting is finished, the trigger will be released by the user, and the data of current single cutting length and cutting speed will be set to zero. But the total cutting distance will be accumulative. When the total cutting distance reaches a certain value, the saw blade should be exchanged.

Optionally, an over-heat or over-current protect unit can be connected to the CPU 1. The protect unit senses the temperature of the motor or electrical current supplied to the motor and disconnects the power supply to the motor when the temperature of the motor is higher than a threshold temperature or the electrical current becomes higher than a threshold current for a period of time (for example, 5 or 10 seconds). Thus, the motor of the saw can be protected from overheat or burning.

Optionally, means for sensing and controlling the tilt angle of the saw blade may be connected to the CPU 1. The tilt angle can be displayed by the display 4 and can be adjusted under the command of the CPU 1.

Optionally, means for sensing and controlling the cutting depth of the saw blade cutting into the workpiece may be connected to the CPU 1. The cutting depth can be displayed by the display 4 and can be adjusted under the command of the CPU 1.

Optionally, the control accessory further comprises a computer connection port for connecting with an external computer to input or renew the program of the CPU 1. It can be understood that other components can also be added into the control accessory.

Further, the cutting speed or the rotational speed of the saw blade can be used as a protective index. When the saw blade encounters an area in the workpiece which is too hard to be cut, the cutting speed and/or the rotational speed of the saw blade may become too low even zero. Then the CPU 1 may disconnect the power supply of the motor by means of the power supply control unit 5 and activate the alarm 7 to indicate this condition.

The invention discloses a new method for achieving exact cutting by a circular saw. The circular saw equipped with the above described control accessory can let the end user know more about the cutting process and the status of the saw. There is a display which can show some or all of the following parameters:

a) Total cutting distance of the saw;

b) Cutting length of current single cut;

c) Target cutting distance preset by end user;

d) Live speed of cutting;

e) Date and time; and

f) Any other operation parameters.

As a result, the end users can perform a cutting with the target distance exactly preset themselves. With the shown cutting speed and total cutting distance, the end user can know more about their saws so that to take good care of their saws and get a longer life endurance.

The control accessory can be incorporated into any type of circular saws, such as table circular saws and portable circular saws, and can be used to cut any material, such as wood, plastic materials, metals, composite materials, or the like.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. The attached claims and their equivalents are intended to cover all the modifications, substitutions and changes as would fall within the scope and spirit of the invention.

Claims

1. A circular saw comprising:

a saw blade;

a motor for driving the saw blade; and

2. The circular saw of claim 1, wherein the control accessory comprises:

a CPU having a timer and an arithmometer; and

a trigger, a distance sensor and a display, all connected with the CPU;

3. The circular saw of claim 2, wherein the trigger is a mechanical trigger or an electrical trigger.

4. The circular saw of claim 2, wherein the distance sensor is a contact sensor or a non-contact sensor.

5. The circular saw of claim 2, wherein the distance sensor is an optoelectronic distance sensor, an ultrasonic distance sensor, or a laser distance sensor.

6. The circular saw of any claims 2 to 5, wherein the control accessory further comprises a power supply control unit which is connected between the CPU and a power supply of the motor of the saw so as to switch off the power supply according to the command from the CPU.

7. The circular saw of claim 6, wherein the control accessory further comprises a key board which is a man-machine interface for pre-setting operation parameters of the circular saw and loading former operation parameters stored in the CPU.

8. The circular saw of claim 7, wherein the control accessory further comprises an alarm for indicating the end or a malfunction of the cutting operation of the saw.

9. The circular saw of claim 8, wherein the alarm is an audio and/or video alarm.

10. The circular saw of claim 8, wherein the cutting operation of the circular saw comprises the following steps:

Step S3, in which the distance sensor sends impulse signals to the CPU, and at the meantime, the timer and the arithmometer start to work;

Step S4, in which the CPU processes the impulse signals to determine current cutting length;

Step S5, in which related data are displayed by the display;

11. The circular saw of claim 10, wherein the cutting parameters of the circular saw includes at least one of:

1) total cutting distance; 2) current single cutting length;

3) target length;

4) cutting speed; and

5) Date and time.

12. The circular saw of any claims 2 to 11, wherein the control accessory further comprises an over-heat or over-current protect unit which is connected to the CPU for sensing the temperature of the motor or electrical current supplied to the motor; wherein the CPU disconnects the power supply to the motor when the temperature of the motor is higher than a threshold temperature or the electrical current becomes higher than a threshold current for a period of time.

13. The circular saw of any claims 2 to 12, wherein the control accessory further comprises means for sensing and controlling the tilt angle of the saw blade as a cutting parameter of the circular saw.

14. The circular saw of any claims 2 to 13, wherein the control accessory further comprises means for sensing and controlling the cutting depth of the saw blade cutting into the workpiece as a cutting parameter of the circular saw.

15. The circular saw of any claims 2 to 14, wherein the control accessory further comprises computer connection port.

16. The circular saw of any claims 2 to 15, wherein the CPU disconnects the power supply to the motor when the cutting speed and/or the rotational speed of the saw blade become lower than corresponding predetermined values.

17. The circular saw of any claims 2 to 16, wherein the circular saw is a table circular saw or a portable circular saw.

18. The circular saw of any claims 2 to 17, wherein the circular saw is configured for cutting wood, plastic materials, metals, or composite materials.