DE69200398T2 - Motor mount for handheld device. - Google Patents

Description

The invention relates to a holder for an electric motor that can be suspended from a belt to drive a hand-held device.

When repairing window frames (removing parts in poor condition) rotary hand tools such as cutters (cutting tools) and the like are often used. In particular, the tool is driven by a high-speed motor (24,000 rpm) via a flexible shaft.

One obstacle encountered in practice is that if the flexible shaft is bent too sharply, an unacceptable build-up of heat occurs between the rotating drive shaft and the stationary casing. Normally the motor is carried in a kind of casing on a belt, with the drive shaft pointing vertically upwards or downwards, as shown, for example, in GB-A-1 075 857.

During operation, the flexible shaft is sometimes unconsciously pulled too tightly into a bend, which creates the above-mentioned obstacle of excessive heat generation. If the flexible shaft is prevented from being pulled too tightly by making the shaft longer, there is an inherent disadvantage that accidents can occur if the shaft gets caught behind an object or otherwise, especially when the operation is carried out in confined spaces.

Similar problems arise with a motor mount as described in GB- A-159 576, in which a motor driving a hand-held device via a flexible shaft is attached to a strap worn across the shoulder. Due to the flexibility of the shoulder strap, the drive motor can swing in an uncontrolled manner.

The present invention relates to a belt-suspendable holder of the type disclosed in the preamble of claim 1 (US-A-3 219 129).

According to the invention, the holder, in particular one for a high-speed motor, has the features disclosed in the characterizing part of claim 1.

When the motor mount according to the invention is used with a certain minimum length of the flexible shaft, a large working area extending longitudinally forward, upward and downward with respect to the user can be covered without excessive bending of the flexible shaft.

In a further development of the invention, the stationary support part can be equipped with two end stops, between which the pivotable holder part can move.

In order to provide some frictional braking effect when the two parts of the holder pivot relative to each other, the two parts may be connected by a pivot pin and an intermediate ring of suitable material, whereby the pivoting part pivots relative to the fixed part before the bend in the shaft becomes unacceptably sharp.

To safely store the tool, an insert tube can be attached above the pivoting part to the fixed part of the holder.

It is noted that it was known per se from US-A-3 219 129 to pivotally mount a portable engine that drives tools via a flexible shaft. However, this relates to an internal combustion engine for a rotary engine or the like, which is carried on the back and pivotable about a vertical axis.

To clarify the invention, an embodiment of the holder for an electric motor for handheld devices will now be described by way of example, with reference to the accompanying drawing, in which:

Fig. 1 is a front view of the holder;

Fig. 2 is a side view; and

Fig. 3 a top view of the holder.

Referring to the drawings, the tool motor holder comprises a fixed support 1 and a motor holder 2 which can be pivoted towards the latter, both of which are made of plate material. The fixed support 1 has side openings 3 formed therein for receiving a belt (not shown). A tube 4 is also attached to the support 1.

The shape of the pivotable motor holder 2 depends on the configuration of the motor to be mounted therein and, in the embodiment shown, has a right-angled end 5 with a passage 6 for the front end 7 of an electric motor 8, which in the case of a cutter for mending wooden articles is typically a high speed motor. Opposite the flanged end 5, the motor holder 2 comprises an axial clamping screw 9 which can engage the rear end of the motor housing, holding it against the bent end 5.

The parts 1 and 2 of the tool motor holder are connected to one another by a pivot axis 10 with the interposition of a sliding disk or a disk 11, which during the pivoting movement of the motor holder 2 generates a certain braking friction such that the motor holder 2, in the absence of load, maintains any pivoting position with respect to the carrier 1 and does not change its pivoting position until a pivoting force is exerted, which is generated by a flexible shaft on the motor 8, which is pulled into a sharp bend.

The pivoting movements of the motor holder 2 on opposite sides of the horizontal position shown are limited by two end stops 12.

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 supported are possible, i.e. a tool motor holder simple in construction and therefore light, which prevents the flexible drive shaft as much as possible from being bent too sharply during work which requires the tool to be moved far from the motor.

Claims (4)

1. A holder for an electric motor that can be suspended from a belt for driving a hand-held device via a flexible shaft, which comprises a plate-shaped support part for suspension from a belt and a motor holder that is pivotally attached to the support part, characterized, that the carrier part (1) can be attached to a belt in a fixed position and that the motor holder part (2) has a plate-shaped part which is pivotably connected to the carrier element (1) in a frictional engagement substantially parallel to the latter, that the carrier part (2) has means (5, 9) extending from the plate-shaped part in which the motor (8) can be fastened with the motor shaft in a substantially horizontal position and parallel to the plate-shaped part, and that the frictional engagement between the carrier part (1) and the holder part (2) is so great that the holder part (2) in the unloaded state maintains any pivotal position with respect to the carrier part (1) until a pivotal force is exerted on it by the flexible shaft of the motor (8). 2. Holder according to claim 2, characterized in that the fixed support part (1) is equipped with two end stops (12) between which the pivotable holder part (2) is movable. 3. Holder according to claim 1 or 2, characterized in that the two parts (1,2) are connected by a pivot axis (10) and a disk (11) of suitable material are connected to one another in such a way that when the flexible drive shaft (13) is bent, the pivotable holder part (2) pivots with respect to the fixed support part before the bend in the shaft becomes unacceptably sharp. 4. Holder according to one of the preceding claims, characterized in that an insert tube (4) for tools is attached to the fixed support part (1) above the pivotable holder part (2).