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EP 0 497 430 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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14.09.1994 Bulletin 1994/37 |
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Date of filing: 31.01.1992 |
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Motor holder for hand-tool
Motorträger für Handgerät
Porte-moteur pour outil à main
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Designated Contracting States: |
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BE DE GB NL |
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Priority: |
01.02.1991 NL 9100181
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Date of publication of application: |
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05.08.1992 Bulletin 1992/32 |
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Proprietor: WINDOW CARE B.V. |
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NL-4202 MN Gorinchem (NL) |
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Inventor: |
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- Blom, Cornelis Willem
NL-2171 TG Sassenheim (NL)
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Representative: Smulders, Theodorus A.H.J., Ir. et al |
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Vereenigde Octrooibureaux
Nieuwe Parklaan 97 2587 BN 's-Gravenhage 2587 BN 's-Gravenhage (NL) |
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References cited: :
CH-A- 666 640 GB-A- 1 075 857
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DE-U- 8 704 878 US-A- 4 106 679
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention relates to a belt-suspendible holder for an electric motor for driving
a hand tool.
[0002] In the mending of window frames (removing parts in bad repair), use is often made
of rotary hand tools, such as cutters and the like. In particular, the tool is driven
via a flexible shaft by a high-speed motor (24,000 rpm).
[0003] An objection experienced in practice is that when the flexible shaft is bent too
sharply, unacceptable heat generation develops between the rotating drive shaft and
the stationary jacket. Normally, the motor is carried in a kind of casing on a belt
with the drive shaft in vertical, upward or downward, orientation, as shown for instance
in GB-A-1 075 857
[0004] During work, the flexible shaft is sometimes unconsciously pulled too tautly into
a bend, giving rise to the above-mentioned objection of great heat generation. Avoiding
the flexible shaft being pulled too taut by making the shaft longer has the inherent
disadvantage that accidents may occur when the shaft is caught behind some object
or other, in particular when work in done in limited spaces.
[0005] Similar problems arise with a motor suspension as described in GB-A-189 576 where
a motor which drives a hand tool via a flexible shaft is attached to a belt carried
across the shoulder. Owing to the flexibility of the shoulder belt, the driving motor
may swing in an uncontrolled manner.
[0006] The present invention concerns a belt-suspendible holder of the type disclosed in
the preamble of claim 1 (US-A-3 219 129).
[0007] According to the invention, the holder, particularly one for a high-speed motor,
has the features disclosed in the characterizig part of claim 1.
[0008] When using the motor holder according to the invention, with a certain minimum length
of the flexible shaft, a large working area extending in lateral, forward, upward
and downward direction relative to the user can be covered without undue bending of
the flexible shaft.
[0009] In further elaboration of the invention, the fixed carrier member may be fitted with
two end stops between which the pivoting holder member is movable.
[0010] To provide some frictional braking action when the two members of the holder pivot
relative to each other, the two members may be interconnected by a pivot and an intermediate
ring of appropriate material, so that upon bending of the flexible drive shaft, the
pivoting member pivots relative to the fixed member before the bend in the shaft becomes
unacceptably sharp.
[0011] For safe storage of the tool, an insertion tube may be mounted on the fixed member
of the holder above the pivoting member.
[0012] It is observed that it is known per se from U.S.-A-3,219,129 to pivotally mount a
portable motor which drives tools via a flexible shaft. However, this concerns a combustion
engine for a rotary mower or the like, which is carried on the back and can be pivoted
on a vertical shaft.
[0013] To clarify the invention, one embodiment of the holder for an electric motor for
hand tools will now be described, by way of example, with reference to the accompanying
drawings, in which:
Fig. 1 is a front view of the holder;
Fig. 2 is a side elevation; and
Fig. 3 is a top plan view of the holder.
[0014] Referring to the drawings, the tool motor holder comprises a fixed carrier 1 and
a motor holder 2 which can be pivoted relative thereto, both made of plate material.
Formed in the fixed carrier 1 are lateral apertures 3 for receiving a belt (not shown).
Further, a tube 4 is mounted on the carrier 1.
[0015] The shape of the pivoting motor holder 2 depends on the configuration of the motor
to be mounted therein and, in the embodiment shown, has an end 5 bent over at right
angles, having a passage 6 for the front end 7 of an electric motor 8, which, in the
case of a cutter for mending woodwork, is typically a high-speed motor. Opposite the
flanged end 5, the motor holder 2 comprises an axial clamping screw 9 which can engage
with the rear end of the motor housing, thereby retaining it against the bent end
5.
[0016] The members 1 and 2 of the tool motor holder are interconnected by a pivot 10 with
interposition of a sliding disc or washer 11 generating a certain braking friction
during pivotal motion of the motor holder 2, in such a manner that when unloaded,
the motor holder 2 retains any pivotal position relative to the carrier 1 and does
not change its pivotal position until a pivotal force is exerted, generated by a flexible
shaft on the motor 8 being pulled into a sharp bend.
[0017] Pivotal motions of the motor holder 2 on opposite sides of the horizontal position
shown are limited by two end stops 12.
[0018] It will be clear that the invention is not limited to the embodiment described, but
that various modifications are conceivable without departing from the scope of the
invention. Thus, adaptations to the shape of the motor to be carried are possible
i.e., a constructionally simple and hence light tool motor holder preventing as much
as possible the flexible drive shaft from being bent too sharply during work requiring
the tool to be moved far from the motor.
1. A belt-suspendible holder for an electric motor for driving a hand tool via a flexible
shaft, comprising a plate-shaped carrier member for suspension from a belt and a motor
holder member, pivotly connected to the carrier member, characterized in that said
carrier member (1) is mountable on a belt in a fixed position and said motor holder
member (2) has a plate-shaped part substantially parallel to and pivotally connected
(10) to the carrier member (1) in frictional engagement therewith, said holder member
(2) having means (5, 9) extending from the plate-shaped part in which the motor (8)
can be fixed with the motor shaft in a substantially horizontal position and parallel
to the plate-shaped part thereof, the frictional engagement between the carrier member
(1) and the holder member (2) being such that when unloaded the holder member (2)
retains any pivotal position relative to the carrier member (1) until a pivotal force
is exerted thereon by the flexible shaft of the motor (8).
2. A holder according to claim 1, characterized in that the fixed carrier member (1)
is fitted with two end stops (12), between which the pivoting holder member (2) is
movable.
3. A holder according to claim 1 or 2, characterized in that the two members (1,2) are
interconnected by a pivot (10) and a washer (11) of appropriate material, in such
a manner that upon bending of the flexible drive shaft (13) the pivoting holder member
(2) pivots relative to the fixed carrier member (1) before the bend in the shaft becomes
unacceptably sharp.
4. A holder according to any one of the preceding claims, characterized in that an insertion
tube (4) for tools is mounted on the fixed carrier member (1) above the pivoting holder
member (2).
1. An einem Gurt aufhängbarer Halter für einen Elektromotor zum Antrieb eines Handgeräts
über eine biegsame Welle, welches ein plattenförmiges Trägerteil zur Aufhängung an
einem Gurt und einen Motorhalter umfaßt, der an dem Trägerteil schwenkbar angebracht
ist,
dadurch gekennzeichnet,
daß das Trägerteil (1) an einem Gurt in einer festen Lage anbringbar ist und daß das
Motorhalterteil (2) ein plattenförmiges Teil hat, welches im wesentlichen parallel
zu dem Trägerelement (1) mit diesem schwenkbar in Reibeingriff stehend verbunden ist,
daß das Trägerteil (2) Mittel (5,9) aufweist, die sich von dem plattenförmigen Teil,
in dem der Motor (8) mit der Motorwelle in einer im wesentlichen horizontalen Lage
und parallel zu dem plattenförmigen Teil befestigt werden kann, erstrecken, und daß
der Reibeingriff zwischen dem Trägerteil (1) und dem Halterteil (2) so groß ist, daß
das Halterteil (2) im unbelasteten Zustand jedwede Schwenkstellung bezüglich des Trägerteils
(1) behält, bis eine Schwenkkraft auf jenes durch die biegsame Welle des Motors (8)
ausgeübt wird.
2. Halter nach Anspruch 2,
dadurch gekennzeichnet,
daß das feste Trägerteil (1) mit zwei Endanschlägen (12) ausgestattet ist, zwischen
denen das schwenkbare Halterteil (2) beweglich ist.
3. Halter nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß die beiden Teile (1,2) durch eine Schwenkachse (10) und eine Scheibe (11) geeigneten
Materials derart miteinander verbunden sind, daß beim Biegen der biegsamen Antriebswelle
(13) das schwenkbare Halterteil (2) bezüglich des feststehenden Trägerteils schwenkt,
bevor die Biegung in der Welle unannehmbar scharf wird.
4. Halter nach einem der vorangehenden Ansprüche,
dadurch gekennzeichnet,
daß ein Einsatzrohr (4) für Werkzeuge über dem schwenkbaren Halterteil (2) an dem
feststehenden Trägerteil (1) angebracht ist.
1. Support suspendu par courroie, pour un moteur électrique servant à entraîner un outil
manuel par l'intermédiaire d'un arbre flexible, comportant un organe de support en
forme de plaque, destiné à être suspendu à une courroie, et un organe portant le moteur
relié à pivotement à l'organe de support, caractérisé en ce que ledit organe de support
(1) est monté en position fixe sur une courroie, et ledit organe (2) portant le moteur
présente une partie en forme de plaque, essentiellement parallèle à l'organe de support
(1) et reliée à pivotement (10) à celui-ci par contact à friction, ledit organe porteur
(2) présentant des moyens (5, 9) en saillie par rapport à la partie en forme de plaque,
dans lesquels le moteur (8) peut être fixé avec l'arbre du moteur en position essentiellement
horizontale et parallèle à sa partie en forme de plaque, le contact à friction entre
l'organe de support (1) et l'organe porteur (2) étant tel que lorsqu'il n'est pas
en charge, l'organe porteur (2) conserve toute position de pivotement par rapport
à l'organe de support (1) jusqu'à ce qu'une force de pivotement soit exercée sur lui
par l'arbre flexible du moteur (8).
2. Support selon la revendication 1, caractérisé en ce que l'organe fixe de support (1)
est équipé de deux arrêts d'extrémité (12) entre lesquels l'organe porteur pivotant
(2) peut se déplacer.
3. Support selon la revendication 1 ou 2, caractérisé en ce que les deux organes (1,
2) sont reliés par un pivot (10) et une rondelle (11) en matériau approprié, de telle
sorte que lorsque l'arbre flexible d'entraînement (13) est courbé, l'organe porteur
(2) pivote par rapport à l'organe de support (1) avant que la flexion de l'arbre devienne
inacceptablement accusée.
4. Support selon l'une quelconque des revendications précédentes, caractérisé en ce qu'un
tube d'insertion (4) pour outils est monté sur l'organe fixe de support (1), au-dessus
de l'organe porteur (2).