AU2012265600B2

AU2012265600B2 - Rotary hand tool with an anti-rotation control module

Info

Publication number: AU2012265600B2
Application number: AU2012265600A
Authority: AU
Inventors: Michel Gleizolles
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2012-01-05
Filing date: 2012-12-19
Publication date: 2015-06-25
Anticipated expiration: 2032-12-19
Also published as: CN103192355B; NZ604986A; KR20130080807A; EP2612733A2; CN103192355A; EP2612733A3; EP2612733B1; FR2985447A1; JP2013139081A; FR2985447B1; AU2012265600A1

Abstract

A hand tool (1) with an electric engine (3) for rotationally driving a member (2) to be driven, characterized in that it comprises means (5) for 15 slowing down the engine (3) and means (6) for detecting the rotational driving of the tool (1) so as to control the slowing down means (5) of the engine. This invention applies well to drills, screwing machines, millstones or other rotary hammers. (Single Fig.) No

Description

Australian Patents Act 1990 - Regulation 3.2 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention Title Rotary hand tool with an anti-rotation control module The following statement is a full description of this invention, including the best method of performing it known to me/us: P/00/01I 5102 1a This invention relates to hand tools provided with an electric motor, for rotationally 5 driving an anchoring, drilling or fastening member. Reference is mainly made herein to drills, screwing machines, millstones, or other rotary hammers. With such tools, the risk could occur that the member to be rotationally driven gets suddenly 10 blocked, for example, when a drill bit of a drill strikes a metal part. Consequently, it is the tool which is driven in rotation and which is able to hurt the operator's hand or arm. From document US 2004/0104034, a hand tool 15 is known, comprising, between the motor and the member to be driven, a safety clutch controlled by a torque active control safety module, comprising a detector being sensitive to an angular shift, and cutting the driving of the motor when the member to be driven no 20 longer moves. Such a prior art tool, however, has the drawback of having quite a short life. According to the invention there is provided a hand tool with an electric motor for rotationally 25 driving a member to be driven, comprising means for slowing down the motor and means for detecting the rotational driving of the tool so as to control the slowing down means of the motor in response to a signal representative of the rotational speed of the 30 tool exceeding a signal representative of a threshold speed, the means for detecting the rotational driving of the tool comprising a contactor being arranged for insulating the motor from its electric supply and for 2 transforming it into a current generator of which the current is re-injected in inverse polarity into the motor. Thus, instead of stopping the driving of the 5 motor, the motor is only slowed down as soon as the tool starts rotating, considerably improving the life of the tool. Moreover, the motor becomes a current generator. The generated current is re-injected in inverse polarity into the motor, thereby ensuring a 10 fast slowing down in the tool rotation. Advantageously, the means for detecting the rotational driving of the tool comprise a gyroscopic detector. This invention will be better understood 15 using the following description of a hand tool of this invention with reference to the single figure showing a functional block diagram, with its electric motor for driving a member to be driven and its control module for slowing down the motor, in the case of the 20 rotation being blocked for the member to be driven. With reference to the Fig., a hand tool 1, here, but actually as an example, a rotary hammer adapted to rotationally drive a drill bit 2, comprises an electric motor 3 for driving the drill bit 2, and a 25 control module 4, intended to prevent the tool from rotating when the drill bit 2 suddenly gets blocked, as a result, for example, of the same meeting a metallic part upon the drilling operation. The control module 4 comprises a block 5 for 30 slowing down the motor 3 and means for detecting the rotational driving of the tool 1 controlling the slowing down block 5. The detecting means here comprise a gyroscopic sensor 6 substantially arranged 3 along the rotation axis 7 of the tool. An electronic filter 8 is connected with the output of the gyroscope 6 for removing the noise generated by the normal operation of the tool. The slowing down block 5 5 is connected to the output of the filter 8. As soon as the tool is started, the gyroscope 6 could detect the rotation of the tool. The output signal of the filter 8 as well as that of a quartz 9 are received in a calculator 10 of 10 a microcontroller 11 delivering, in output, a signal V(8)being representative of the rotation speed of the tool. The signal V(G) is compared, in a comparator 12, to a signal being representative of a threshold speed V (s). Such a speed V (s) could be 15 determined by a software part 13 embedded into the microcontroller 11. The output signal of the comparator 12 is sent to a contactor 14 being active as soon as V (0) > V (s) 20 The contactor 14 is connected to the motor 3. The activation of the contactor 14 insulates the motor from its electric supply. Thus, the motor becomes a current generator. The generated current is re-injected in inverse polarity into the motor, 25 thereby ensuring a fast, even sudden, slowing down of the tool. Such an action of insulation and phase inversion of the motor could occur on a field effect transistor FET of the motor. 30 It should be noticed that the activation of the transistor FET should be as fast as possible. This is why, as a contactor, an electromechanical contactor is preferred having a very fast reaction. In addition, 4 this is a particularly robust equipment material. Thus, it could be hoped that the tool is rotationally driven on less than one quarter of revolution. The just described assembly is thus a 5 slowing down module. It could be arranged on any electric motor tool, on which an unexpected rotational blocking could occur. The risks of accident of the type fracture or sprain at the level of operators' arms are thereby restricted. 10 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to 15 imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 20 The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or 25 information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. The reference numerals in the following 30 claims do not in any way limit the scope of the respective claims.

Claims

1. A hand tool with an electric motor for rotationally driving a member to be driven, 5 comprising means for slowing down the motor and means for detecting the rotational driving of the tool so as to control the slowing down means of the motor in response to a signal representative of the rotational speed of the tool exceeding a 10 signal representative of a threshold speed, the means for detecting the rotational driving of the tool comprising a contactor being arranged for insulating the motor from its electric supply and for transforming it into a current generator of 15 which the current is re-injected in inverse polarity into the motor.

2. The hand tool according to claim 1, wherein the means for detecting the rotational driving of the 20 tool comprise a gyroscopic detector.

3. The hand tool according to claim 1, wherein the contactor is an electromechanical contactor. 25

4. A hand tool substantially as hereinbefore described with reference to the accompanying drawings.