Power tool having control means for monitoring screw tightening operations

• US 7,673,701 B2
• Filed: 08/29/2007
• Issued: 03/09/2010
• Est. Priority Date: 08/31/2006
• Status: Expired due to Fees

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Katou, Makoto, Miyazaki, Hiroshi, Tanaka, Naotake
• Primary Examiner(s): Nash; Brian D
• Application Number:
  US11/892,976
• Publication Number:
  US 20080257577A1
• Time in Patent Office: 923 Days
• Field of Search: 173/4, 173/11, 173/18, 173/20, 173/217, 173/176, 81/571.1
• US Class Current: 173/4
• CPC Class Codes: B25B 21/00 Portable power-driven screw or nut setting or loosening tools; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; for mounting or dismounting wheels B60B29/006; Attachments for drilling apparatus serving the same purpose machines B23P19/06
• CPC Class Codes: B25B 21/002 for special purposes
• CPC Class Codes: B25F 5/006 Vibration damping means
• CPC Class Codes: B25F 5/02 Construction of casings, bodies or handles B25F5/006, B25F5/008 take precedence

Abstract

A power tool includes a driving unit for performing screw tightening operations; a motor for rotatably driving the driving unit; a rechargeable battery pack; a trigger switch for turning on and off the motor; and a control circuit, accommodated in a main body of the power tool, for monitoring the screw tightening operations. The control circuit has a screw tightening completion detection unit for detecting completion of a screw tightening operation, a screw tightening count unit for counting the number of detected tightening operations, a screw tightening number setting unit for presetting the number of screws to be tightened, a screw tightening completion notifying unit for notifying completion of the screw tightening operations when the number of detected tightening operations reaches the preset number. Further, the screw tightening number setting unit and the screw tightening completion notifying unit is disposed at a lower front portion of a grip portion.

Claims

1. A power tool comprising:

a driving unit for performing screw tightening operations;

a motor for rotatably driving the driving unit;

a rechargeable battery pack;

a trigger switch for turning on and off the motor; and

a control circuit, accommodated in a main body of the power tool, for monitoring the screw tightening operations, wherein the control circuit has a screw tightening completion detection unit for detecting completion of a screw tightening operation;

a screw tightening count unit for counting the number of completed screw tightening operations detected by the screw tightening completion detection unit;

a screw tightening number setting unit for presetting the number of screws to be tightened; and

a screw tightening completion notifying unit having a piezoelectric buzzer for notifying completion of the screw tightening operations when the number of completed screw tightening operations reaches the preset number of screws, and wherein the screw tightening number setting unit and the screw tightening completion notifying unit are disposed at a lower front portion of a grip portion in the main body of the power tool, for being held by a hand,

wherein the piezoelectric buzzer produces one of selectable alarm sounds having different pitches.

2. The power tool of claim 1, wherein a protruded elastomer is installed around an outer periphery of the lower front portion of the grip portion.

3. The power tool of claim 1, wherein the screw tightening number setting unit includes a “

mode”

button, a “

+”

button and a “

−

”

button, and a sound setting mode is initiated by setting the “

mode”

button longer than a predetermined time.

4. The power tool of claim 1, wherein the screw tightening number setting unit is provided with a hold function to prevent the preset number of screws to be fastened from being changed.

5. The power tool of claim 1, wherein a body portion and the grip portion of the main body of the power tool are connected rotatably such that an angle therebetween is changed freely and the display of the number of tightening operations set by the screw tightening number setting unit provided at the lower front portion of the grip portion is displayed upside down.

6. The power tool of claim 3, wherein the predetermined time is 2 seconds.

7. The power tool of claim 3, wherein the pitches of the alarm sounds are changeable by pressing the “

+”

button or the “

−

”

button in the sound setting mode and if the “

mode”

button is pressed while one of the alarm sounds having a specific pitch is produced, the alarm sound having that pitch is selected and stored.