Tool driving or impacting – Means to drive tool about an axis – Electric motor
Reexamination Certificate
1998-08-25
2001-01-23
Calve, Jim (Department: 3721)
Tool driving or impacting
Means to drive tool about an axis
Electric motor
C173S029000, C173S170000, C310S050000, C408S004000, C408S020000
Reexamination Certificate
active
06176322
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power tool and, in particular, to a power tool having a conventional body portion and provided with a plurality of interchangeable tool heads.
2. Description of the Related Art
As a result of considerable developments within the field of power tools and the increased demand of the DIY market, the number of different types of power tool available to the consumer has risen considerably in the past decade. In particular even the most reluctant of DIY enthusiasts will own a power drill and jigsaw, whilst their more enthusiastic counterparts will also require electric sanders, power files, nibblers and other specialised power tools having dedicated purpose. Whilst this considerable array of power tools is often found to be useful, owning such a large number is both expensive and requires a considerable amount of storage space. In addition, having one specialised tool to perform each job often results in significant under-utilage of such a tool which are, generally, all operated by similar motors. Still further, many of todays power tools are “cordless”, being battery powered by rechargeable batteries, often requiring the user to change the battery pack when changing dedicated tools, or have several ready-charged batteries available for different tools. These current solutions are cumbersome or expensive respectively.
Attempts have been made to improve utilage of such power tools and to provide solutions to the above problems by the inclusion of attachments for a conventional drill, whereby the drill chuck is used to engage a drive mechanism of a reciprocating saw blade, an example of which is seen in U.S. Pat. No. 1,808,228. Another example of a multi functional tool shown in German Gebrauchsmuster 9010138 which shows a conventional drill body having a plurality of drill heads which operate at different speeds dependent on the gear reduction mechanism incorporated in those heads. However, the drawback of systems of this type is that where a drill chuck is used to operate a drive mechanism for a reciprocating saw, considerable energy is lost in the conversion mechanism of firstly driving a drill chuck which then drives the saw mechanism. Alternatively, where the tool incorporates interchangeable drill heads the variety of functions are somewhat limited to altering the speed of drilling.
It is therefore an object of the present invention to provide a power tool system which alleviates the aforementioned problems and allows for maximum utilage of that power tool.
BRIEF SUMMARY OF THE INVENTION
According to the present invention there is provided a power tool system comprising a tool body having an activation switch controlling a motor with a direct rotary output, and a plurality of interchangeable tool heads each for connection with said body so as to engage with said motor output, characterised in that said tool body incorporates a releasable lock-off mechanism which restrains actuation of said activation switch when none of the tool heads of the plurality are connected to the body and each tool head of the plurality comprises actuating means to engage with and de-activate said lock-off mechanism when a tool head of the plurality is connected to said body to allow actuation of said switch.
Preferably a system wherein said actuating means on at least one of the tool heads of the plurality automatically engages and de-activates said lock-off mechanism when said tool head is connected to said body.
Preferably a system wherein said actuating means on at least one of the tool heads of the plurality is manually displaceable so as to engage and de-activate said lock-off mechanism when said tool head is connected to said body.
Preferably, a system wherein said lock-off mechanism comprises a pivotally mounted elongate member having a first end thereof resiliently biased into restraining engagement with said switch.
A system in which said first end of the elongate member has a projection for abutting engagement with said switch.
Furthermore, a system wherein the elongate member has a second end pivotally opposed to said first end and externally accessible, in which said second end comprises a cam surface for cam engagement with said actuating means on each of the tool heads of the plurality when connected to said body so as to pivot said elongate member about its pivot point and displace said first end out of engagement with said switch.
It is preferable a system in which said actuating means comprises a cam follower surface for cam engagement with said cam surface of said second end.
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Black & Decker Inc.
Calve Jim
Shapiro Bruce S.
LandOfFree
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