A PORTABLE TOOL COMPRISING AN ENGINE PLACED AT ONE END OF AN ELONGATED TUBE AND A WORKING TOOL PLACED IN THE OPPOSITE END .

Technical field

Appliance for a portable tool comprising an engine placed at one end of an elongated tube and a working tool placed in the opposite end of the tube. A drive shaft extends inside the tube from the engine to a first gear located inside a gear housing in the opposite end of the tube. A drive pin for the working tool extends from a second gear in contact with the first gear.

Background of the invention

Engine powered portable tool are widely used to facilitate work in forests, gardens and parks. There are a number of different types of tools available like for example trimmers, clearing saws, cutters for pruning of trees and saws for mulching of vegetation. These tools are available in different sizes to meet the requirements for different kinds of work. The smallest ones are hand held while bigger and heavier tools are carried in an ergonomic harness or strap placed around the shoulders of the operator. These types of portable tools have the engine and related components placed in one end of an elongated tube. A drive shaft is extending inside the tube to a first gear in contact with a second gear. The first and second gears are located inside a gear housing secured to the tube in the opposite end as the engine. A working tool is releasable secured to a drive pin extending from the second gear to make it possible to replace worn out working tools.

All these different types of tools however require that an operator is in the possession of several different tools to cover the entire range of work that needs to be done in forests and gardens. The use of a different type of working tool in combination with a tool not intended for that specific working tool, in order to reduce the number of different tools required by the operator, has turned out to some times cause severe structural damages to the components placed in the working tool end of the tool. This is due to different, and in some cases increased, loads on the components in the working tool end of the tool.

Object of the invention

The objects of the claimed invention is to provide an appliance that increases the strength of the components in the working tool end of the tool and thereby reduce the number of required types of tools for the operator.

Summary of the invention

The problems disclosed above are solved by the claimed appliance with the features defined in the characterising portion of the independent claim.

The claimed appliance is a separate gear housing support comprising a first and a second clamping member placed opposite each other around the gear housing and the tube. The ends of the first and second clamping members placed towards the tube are configured to be clamped around the tube by a first tensioning means, while the opposite ends of the clamping members are configured to be clamped around the gear housing by a second tensioning means. The appliance supports the first and second gear, the gear housing and the fastening of the gear housing in the tube when a working tool that exposes the different components for increased loads is used.

The claimed appliance acts as a reinforcement of the first and second gear, the gear housing and the fastening of the gear housing in the tube and makes it possible to alternate the type of working tool used. Consequently, the number of tool types required by the operator is reduced considerably by the use of the claimed invention.

Another advantage with the appliance is that it is easily mounted on the tool when the working tool is changed to a type exposing the involved components to larger loads that the tool is originally designed for.

The appliance also provides a fastening means for a working tool cover that is needed when a different type of working tool than the type that the tool is designed for is used.

Brief description of the drawings

One embodiment of the claimed invention will be described with reference to the figures.

Figure 1. Illustrates a portable tool with the working tool placed in the end of an elongated tube.

Figure 2. Illustrates an exploded view of the claimed appliance and the working tool end of the tool. Figure 3. Illustrates an exploded view of the appliance in figure 2.

Detailed description of the drawings

A portable tool 10 is disclosed in figure 1. The tool 10 comprises an engine 11 and related components placed in one end of an elongated tube 12. The tube 12 has a circular cross section and is normally made of a metallic or plastic material. Other cross-sectional shapes like oval or square as well as other materials could also be used. The tool 10 is provided with a handle 13 secured to the tube 12. The position of the handle 13 is adjustable along the tubel2. The position is selected to be comfortable for the operator.

Inside the tube 12 is a drive shaft extending from the engine 11 to a first gear in the opposite end of the tube 12. The drive shaft is normally supported by one elongated bearing or a number of bearings placed along the drive shaft inside the tube 12. The bearing is not illustrated in the drawings. A drive pin 15 is extending from a second gear in contact with the first gear. A working tool 16, illustrated in figure 2, is secured to the drive pin 15. A threaded portion 30 in the end of the drive pin 15 and a nut 31 achieves the securing so that the working tool 16 is releasable and easy to replace or change to a different type of working tool

16. The first and second gear is surrounded by a gear housing 17 that prevents dirt and cut vegetation from damaging the components inside the gear housing 17.

In figure 2 is one embodiment of the claimed gear housing support 18 illustrated. The gear housing support 18 comprises a first clamping member 19 and a second clamping member 20. The first 19 and second 20 clamping members are placed opposite each other around the gear housing 17 and the tube 12 and are configured to be clamped around the gear housing 17 and the tube 12. The clamping members 19 and 20 are extending in the same longitudinal direction as the longitudinal direction of the tube 12. One end of the first 19 and the second

clamping member 20 is secured around the tube 12. The contact surface between the clamping members and the tube 12 on the clamping members are shaped to be in contact with the outer surface of the tube 12. The other ends of the first 19 and second 20 clamping members are secured around the gear housing 17 and shaped to be in contact with the outside surface of the gear housing 17 in order to support and strengthen the gear 14, the gear housing 17 and the securing of the first and second gear and the gear housing 17 in the tube 12.

A first tensioning means 21 is placed in the end of the gear housing support 18 positioned towards the tube 12 and a second tensioning 22 means is placed in the other end. The first 21 and the second 22 tensioning means consist of two screw joint reinforcements 23 respectively. The screw joint reinforcements are placed so that the clamping members 19 and 20 are secured around the tube 12. Each screw joint reinforcement comprises a screw 24 passing through a hole 32 in the first clamping member 19 and then secured in a thread 25 in the second clamping member 20.

The second clamping member 20 is provided with a protruding flange 26 placed close to the tube end of the second clamping member 20. The protruding flange 26 extends in substantially radial direction from the tube 12 and is used for fastening of a working tool cover 27 in order to prevent cut vegetation from being thrown at the operator. The working tool cover 27 is extending over a sector of the periphery of the rotating working tool 16 and is fastened to the protruding flange 24 by four screws 28 and nuts 29. The illustrated working tool 16 is a mulching blade used for cutting bushes and small trees into small pieces. The working tool type is however easily changed to for example a saw blade or a string trimmer head.