Motor driven screwdriver with spindle lock

• US 4,754,669 A
• Filed: 10/22/1986
• Issued: 07/05/1988
• Est. Priority Date: 10/24/1985
• Status: Expired due to Term

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Verdier, Alain, Serriere, Alain
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/922,059
• Time in Patent Office: 622 Days
• Field of Search: 81/57.14, 81/57.22, 81/57.3, 81/57.31, 81/54, 81/57, 81/57.11, 81/58, 81/58.3, 81/58.4, 81/60, 81/63.1, 81/467
• US Class Current: 81/57.14
• 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

Abstract

In a portable motorized screwdriver, in order to provide for manual use of the screwdriver, to finish screwing in a screw, for example, or to start unscrewing a screw, a mechanism is provided for locking the spindle. This mechanism is coupled to the switch used to start and stop rotation of the spindle. This coupling is arranged so that operation of the switch to start rotation of the spindle is accompanied by unlocking of the spindle and so that returning the switch to the position to stop rotation of the spindle locks the spindle. The locking mechanism is arranged so that when the spindle is locked the screwdriver may be used as a ratchet type manual screwdriver.

Claims

1. Portable motorized screwdriver, comprising:

a tool casing;

a tool-bearing spindle rotatably mounted in said tool casing;

drive mean adapted to rotate said spindle in respective opposite directions;

manual switching means adapted to cause said drive means selectively to rotate said spindle in one or other of said respective opposite directions or to stop said drive means;

locking means adapted to enable or prevent rotation of said spindle relative to said tool casing, said locking means being coupled to said manual switching means in such a way that actuation of said manual switching means to cause said drive means to rotate said spindle in one or other of said respective opposite directions causes said locking means to enable rotation of said spindle relative to said tool casing at least in said one or other of said respective opposite directions;

said manual switching means being adapted to authorize pre-selection of one or other of said respective opposite directions when said drive means are stopped; and

said locking means being coupled to said manual switching means in such a way that actuating said manual switching means to stop said drive means with a first of said respective opposite directions pre-selected causes said locking means to lock said spindle against rotation relative to said tool casing in the second of said respective opposite directions and to enable rotation of said sindle relative to said tool casing in said first direction, and actuating said manual switching means to stop said drive means with the second of said respective opposite directions pre-selected causes said locking means to lock said spindle against rotation relative to said tool casing in the first of said respective opposite directions and to enable rotation of said spindle relative to said tool casing in said second direction.

2. Motorized screwdriver according to claim 1, wherein said manual switching means comprise a trigger and a trigger-operated switch, and said locking means are mechanically coupled to said trigger in such a way that actuating said trigger to operate said drive means causes said locking means to release said spindle to allow rotation of said spindle relative to said tool casing.

3. Motorized screwdriver according to claim 1, wherein said drive means comprise a motor and a transmission system coupling said motor to said spindle, said manual switching means comprise means for starting and stopping said motor, said transmission system comprises clutch means that are engaged when said motor is running and disengaged when said motor is stopped, and said locking means cooperate with said transmission system on the output side of said clutch means.

4. Motorized screwdriver according to claim 3, wherein said clutch means comprise a centrifugal clutch having a driven part coupled to said motor and a driving part coupled to said spindle.

5. Motorized screwdriver according to claim 1, comprising time-delay means for delaying locking of said spindle relative to stopping of said drive means and for delaying starting of said drive means relative to releasing of said spindle.

6. Motorized screwdriver according to claim 1, wherein said drive means comprise a direct current electric motor having first and second power supply terminals and said manual switching means comprise means for connecting said first and second terminals of said motor respectively to first and second terminals of a direct current power supply in order to operate said drive means so as to rotate said spindle in one of said respective opposite directions and means for connecting said first and second terminals of said motor respectively to said second and first terminals of said power supply in order to operate said drive means so as to rotate said spindle in the other of said respective opposite directions, said manual switching means comprising means for connecting said first and second terminals of said motor together and isolating them from at least one of said terminals of said power supply in order to stop said drive means.

7. Portable motorized screwdriver, comprising:

a tool casing;

a tool-bearing spindle rotatably mounted in said tool casing;

drive means adapted to rotate said spindle in respective opposite directions;

manual switching means adapted to cause said drive means selectively to rotate said spindle in one or other of said respective opposite directions or to stop said drive means; and

locking means, operative between said tool casing and said spindle, for enabling or preventing rotation of said spindle relative to said tool casing, said locking means being coupled to said manual switching means in such a way that actuation of said manual switching means to cause said drive means to rotate said spindle in one or other of said respective opposite directions causes said locking means to enable rotation of said spindle at least in said one or other of said respective opposite directions;

said manual switching means being adapted to authorize pre-selection of one or other of said respective opposite directions when said drive means are stopped;

said locking means being coupled to said manual switching means in such a way that actuating said manual switching means to stop said drive means with a first of said respective opposite directions pre-selected causes said locking means to lock rotation of said spindle relative to said tool casing in the second of said respective opposite directions and to enable rotation of said spindle relative to said tool casing in said first direction;

said drive means comprising a motor, and a transmission system coupling said motor to said spindle and comprising at least one rotatable member rotationally coupled to said spindle;

said locking means comprising at least two locking fingers movable between respective first and second positions, first abutment means, and second abutment means;

said first abutment means being fastened to said at least one rotatable member and adapted to abutt against a first of said at least two fingers in its first position for rotation of said at least one rotatable member in a first direction associated with the first rotation direction of said spindle, to remain free of said first finger in its first position for a second direction of rotation of said at least one rotatable member opposite to its first direction of rotation, and to remain free of said first finger in its second position for both directions of rotation of said at least one rotatable member;

said second abutment means being fastened to said at least one rotatable member and adapted to abutt against a second of said at least two fingers in its first position for said second direction of rotation of said at least one rotatable member, to remain free of said second finger in its first position for said first direction of rotation of said at least one rotatable member, and to remain free of said second finger in its second position for both directions of rotation of said at least one rotatable member; and

said locking fingers being coupled to said manual switching means in such a way that;

said first locking finger assumes its first position when said manual switching means are actuated to stop said drive means and said second direction of rotation of said spindle is preselected,

said second locking finger assumes its first position when said manual switching means are actuated to stop said drive means and said first direction of rotation of said spindle is preselected, and

said first and second locking fingers assume their respective second positions when said manual switching means are actuated to cause said drive means to rotate said spindle in said first or said second direction.

8. Motorized screwdriver according to claim 7, wherein said manual switching means comprise a trigger and a trigger-operated switch and said locking means are mechanically coupled to said trigger in such a way that actuating said trigger to operate said drive means causes said locking means to release said spindle.

9. Motorized screwdriver according to claim 7, wherein said locking means comprise spring means adapted to urge each of said at least two locking fingers towards its respective first position and said at least two locking fingers are coupled to said manual switching means in such a way that:

said first locking finger assumes its first position as a result of the action on it of said spring means when said manual switching means are actuated to stop said drive means and said second direction of rotation of said spindle is preselected.

said second locking finger assumes its first position as a result of the action on it of said spring means when said manual switching means are actuated to stop said drive means and said first direction of rotation of said spindle is preselected,

said first and second locking fingers assume their respective second position when said manual switching means are actuated to cause said drive means to rotate said spindle in said first or second direction.

10. Motorized screwdriver according to claim 9, further comprising an inhibitor member adapted to be disposed between said first finger and said first abutment means when said at least one rotatable member rotates in said second direction, to be disposed between said second finger and said second abutment means when said at least one rotatable member rotates in said first direction, and to be retracted after said manual switching means have been actuated to stop said drive means to prevent contact between said fingers and said abutment means until said drive means have stopped.

11. Motorized screwdriver according to claim 9, further comprising an inhibitor member adapted to be disposed between said first finger and said first abutment means when said at least one rotatable member rotates in said second direction, to be disposed between said second finger and said second abutment means when said at least one rotatble member rotates in said first direction, and to be retracted after said manual switching means have been actuated to stop said drive means to prevent contact between said fingers and said abutment means until said drive means have stopped, wherein said inhibitor member comprises at least one plate associated with said at least one rotatable member and driven coaxially with it and in the same direction as it by friction, further comprising stop means adapted to limit rotation of said at least one plate in said first and second directions of rotation of said at least one rotatable member respectively to an angular position in which said plate is disposed between said second finger and said second abutment means and not disposed between said first finger and said first abutment means and an angular position in which said plate is disposed between said first finger and said first abutment means and not disposed between said second finger and said second abutment means.

12. Motorized screwdriver according to claim 11, wherein said at least two fingers are mutually offset in the circumferential direction with a specific circumferential spacing between them and said plate has a circumferential dimension less than said circumferential spacing.

13. Motorized screwdriver according to claim 7, wherein said drive means comprise a motor and a transmission system coupling said motor to said spindle, said manual switching means comprise means for starting and stopping said motor, said transmission system comprises clutch means that are engaged when said motor is running and disengaged when said motor is stopped, and said locking means cooperate with said transmission system on the output side of said clutch means.

14. Motorized screwdriver according to claim 13, wherein said clutch means comprise a centrifugal clutch having a driven part coupled to said motor and a driving part coupled to said spindle.

15. Motorized screwdriver according to claim 7, comprising time-delay means for delaying locking of said spindle relative to stopping of said drive means and for delaying starting of said drive means relative to releasing of said spindle.

16. Motorized screwdriver according to claim 13, wherein said drive means comprise a direct current electric motor having first and second power supply terminals and said manual switching means comprise means for connecting said first and second terminals of said motor respectively to first and second terminals of a direct current power supply in order to operate said drive means so as to rotate said spindle in one of said respective opposite directions and means for connecting said first and second terminals of said motor respectively to said second and first terminals of said power supply in order to operate said drive means so as to rotate said spindle in the other of said respective opposite directions, said manual switching means comprising means for connecting said first and second terminals of said motor together and isolating them from at least one of said terminals of said power supply in order to stop said drive means.

17. A hand-held power screwdriver, comprising:

a casing;

a motor supported by said casing;

an output spindle rotatably mounted in said casing for rotation by said motor in a forward direction for screwing-in screws and a reverse direction for unscrewing screws;

a manually actuatable switch for selecting the direction for rotation of said spindle by said motor;

means, connected between said casing and said spindle, for locking said spindle relative to said casing to prevent rotation of said spindle relative to said casing in said reverse direction but at the same time to allow rotation of said spindle relative to said casing in said forward direction when said switch is positioned to select the forward direction for rotation of said spindle and said motor is not rotating said spindle, whereby said power screwdriver can be used as a ratchet type manual screwdriver for screwing-in screws; and

the locking means comprising an element movable in a direction parallel to said spindle and engageable with a rotational element rotatable about an axis parallel to said spindle.

18. A handheld power screwdriver, comprising:

a casing;

a reversible electric motor in said casing;

switching means for switching said motor on and off;

selecting means for selecting the rotational direction of said motor;

a spindle having a screwdriver bit holder and being rotatably mounted in said casing for rotation by said motor in screwing and unscrewing directions, respectively;

first ratchet means, operative between said casing and said spindle, for locking said spindle against rotation in the unscrewing direction relative to said casing but allowing rotation of said spindle relative to said casing in the screwing direction;

second ratchet means, operative between said casing and said spindle, for locking said spindle against rotation in the screwing direction reltive to said casing but allowing rotation of said spindle relative to said casing in the unscrewing direction;

said switching means being interconnected with said first and second ratchet means to render both said first and second ratchet means inoperative for locking said spindle relative to said casing when said switching means switches said motor on;

said selecting means being interconnected with said first and second ratchet means to render said first and second ratchet means inoperative, respectively, when said selecting means selects the rotational direction of said motor for the unscrewing and screwing directions, respectively, of said spindle; and

said switching means, said selecting means, said first ratchet means, and said second ratchet means interrelating to enable said power screwdriver to function as a ratchet type manual screwdriver when either direction of rotation of said motor is selected by said selecting means but said motor is switched off.

19. The screwdriver of claim 18, wherein said selecting means has a neutral position in which neither direction of rotation of said motor is authorized, and when said motor is switched off and said selecting means is in said neutral position said spindle is locked against rotation relative to said casing in both said screwing and unscrewing directions by the combined operation of said first and second ratchet means.

20. A portable power screwdriver, comprising:

a casing;

a tool holder spindle rotatably mounted in said casing for rotation relative to said casing in either of two opposite directions of rotation;

an electric motor mounted in said casing for drivingly rotating said spindle;

means for switching said motor on and off;

a one way ratchet mechanism connected between said casing and said spindle and operative when said motor is switched off to enable said power screwdriver to function as a ratchet type manual screwdriver; and

means, interconnected with said switching means and operated thereby, for disconnecting said ratchet mechanism from being operative between said casing and said spindle, and so freeing said spindle for rotation relative to said casing in either of said directions of rotation, when said motor is switched on.

21. A portable power screwdriver, comprising:

a casing;

a tool holder spindle rotatably mounted in said casing;

an electric motor mounted in said casing for drivingly rotating said spindle;

means for switching said motor on and off;

a one way ratchet mechanism connected between said casing and said spindle and operative when said motor is switched off to enable said power screwdriver to function as a ratchet type manual screwdriver; and

said ratchet mechanism comprising;

an element mounted in said casing for movement in a direction parallel to said spindle;

a member rotatably mounted in said casing and connected to said spindle for rotation therewith;

resilient means for urging said element towards a face of said member; and

means, on said face of said member, for cooperating with said element, when urged into contact therewith by said resilient means, to permit rotation of said member in one direction of rotation thereof relative to said casing but at the same time to lock said member against rotation relative to said casing in a direction opposite to said one direction.