Power hand tool having a proximity detector

• US 20030194283A1
• Filed: 04/10/2002
• Published: 10/16/2003
• Est. Priority Date: 04/10/2002
• Status: Active Grant

• Current Assignee: Nanjing Chervon Industry Company Limited (Chervon Holdings Limited)
• Original Assignee: S-B Power Tool Corporation
• Inventors: Kovarik, Illya, Bartholet, Martin
• Granted Patent: US 7,253,541 B2
• Time in Patent Office: Days
• US Class Current: 408/4
• CPC Class Codes: B25F 5/00 Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
• CPC Class Codes: B25F 5/021 with guiding devices guiding devices for hand tools on stands or supports B25H1/0078
• CPC Class Codes: F16D 1/10 Quick-acting couplings in which the parts are connected by simply bringing them together axially
• CPC Class Codes: H03K 17/96 Touch switches specially adapted for electronic time-pieces with no moving parts G04G21/08
• CPC Class Codes: Y10T 408/10 with interlock between machine elements

Abstract

The present invention provides a power tool with a hand proximity detector to detect the hand of an operator and a trigger circuit operable with the detector to control the operation of a light in the housing or to provide a safety lockout function.

Claims

1. A hand tool having a motor powered by a power source and an operating switch for the motor controllable by an operator, comprising:

a housing;

a proximity detector disposed in said housing for detecting the presence of the operator during operation of the tool;

a light located in said housing; and

,

a trigger circuit located within said housing connected to said detector, said light and the power source, said circuit energizing said light when said detector detects the presence of the operator.

2. The tool as defined in claim 1 wherein said light is a light emitting diode.

3. The tool as defined in claim 1 wherein said proximity detector comprises a photocell.

4. The tool as defined in claim 3 wherein said detector is an infrared sensor.

5. The tool as defined in claim 4, further comprising an infrared emitter disposed in said housing.

6. The tool as defined in claim 1 wherein said housing further comprises a handle and said detector is disposed in said handle.

7. The tool as defined in claim 6 comprising a drill wherein said housing comprising a main portion with said handle being integral with said main portion and extending downwardly from said main portion, the drill having a chuck on the forward portion of the main portion of the housing, the operating switch being in the upper front portion of said handle, said light being located in the lower front portion of said handle.

8. The tool as defined in claim 7 wherein said proximity detector being located in the rear of said handle.

9. The tool as defined in claim 1 wherein the power source is an AC source, said trigger circuit comprising:

a converter for converting AC power and providing DC power at its output;

a light connected to said converter output;

a switch connected to said light and to ground;

said detector being connected in said circuit and being operable to control said switch such that said switch is closed in response to said detector detecting the presence of the operator.

10. The tool as defined in claim 9 wherein said light is a light emitting diode having an anode connected to said converter and a cathode connected to said switch.

11. The tool as defined in claim 10 wherein said switch comprises a first transistor that has its control electrode operatively connected to said detector.

12. The tool as defined in claim 11 further comprising a Zener diode connected between the converter and ground, a second transistor connected in circuit between said control electrode of said first transistor and said detector, with the control electrode of said second transistor being connected to said detector and to a resistor, with said resistor being connected to said converter output and said detector also being connected to ground, said detector and resistor comprising a voltage divider that operates to provide a switching voltage to said second transistor when the internal resistance of said detector varies in response to detecting the presence and/or absence of an operator.

13. The tool as defined in claim 9 wherein said converter comprises a full wave diode bridge rectifier.

14. The tool as defined in claim 9 wherein said circuit further comprises a safety lockout operatively connected to the motor to disconnect power to the motor when said light is de-energized by said circuit.

15. The tool as defined in claim 14 wherein said safety lockout comprises a relay connected in circuit with the tool motor and having a relay coil connected in series with said light and operable to close circuit the relay when current is flowing through the coil.

19. The drill as defined in claim 15 wherein said circuit further comprises a safety lockout operatively connected to the drill motor to disconnect power to the motor when said light is de-energized by said circuit.

20. The drill as defined in claim 19 wherein said safety lockout comprises a relay connected in circuit with the tool motor and having a relay coil connected in series with said light and operable to close circuit the relay when current is flowing through the coil.

16. A portable handheld drill having a motor powered by a power source and an operating switch controllable by an operator, the drill having a housing with a main portion and an integral handle extending downwardly from the main portion, the drill having a chuck at the front of the main portion of the housing, the operating switch being in the upper front portion of said handle, the drill comprising:

a trigger circuit located within said housing connected to a proximity detector, a light and the power source, said circuit energizing said light when said detector detects the presence of the operator;

said proximity detector being located in said housing for detecting the presence of the operator during operation of the tool; and

,

said light being located in said housing.

17. The drill as defined in claim 16 wherein said proximity detector comprises an infrared emitter located at one of the rear of the main portion and the lower rear portion of the handle and an infrared sensor located at the other of the rear of the main portion and the lower rear portion of the handle, said infrared emitter and the infrared sensor being positioned so that said infrared sensor detects infrared emissions when the path between the infrared emitter and infrared detector is unobstructed.

18. The drill as defined in claim 16 wherein said proximity detector comprises a light source located at one of the rear of the main portion and the lower rear portion of the handle and a photocell located at the other of the rear of the main portion and the lower rear portion of the handle, said a light source and the photocell being positioned so that said photocell detects light from said light source when the path between the light source and photocell is unobstructed.

21. A portable handheld drill having a motor powered by a power source and an operating switch controllable by an operator, the drill having a housing with a main portion and an integral handle extending downwardly from the main portion, the drill having a chuck at the front of the main portion of the housing, the operating switch being in the upper front portion of said handle, the drill comprising:

a proximity detector disposed in the housing for detecting the presence of the operator'"'"'s hand during operation of the tool;

a light located in said housing; and

,

a trigger circuit located within said housing connected to said detector, said light and the power source, said circuit energizing said light when said detector detects the presence of the operator'"'"'s hand.