GB2125668A

GB2125668A - Flailing line trimmers

Info

Publication number: GB2125668A
Application number: GB08307381A
Authority: GB
Inventors: Robert G Everts
Original assignee: Piston Powered Products Inc
Current assignee: Piston Powered Products Inc
Priority date: 1982-08-31
Filing date: 1983-03-17
Publication date: 1984-03-14
Also published as: AU563302B2; GB8307381D0; GB2125668B; AU4000885A

Abstract

A flailing line trimmer has a handle shaft (12) which permits angular adjustment of a drive head (14) at the end of it. This is effected by a coupling (18) which clamps two parts of the handle shaft together. The coupling prevents rotation of one part and perm its the selective rotation of the other. <IMAGE>

Description

SPECIFICATION Improvements relating to flailing line trimmers This invention relates to flailing line trimmers and more particularly to a handlejointwhich enables the cutting angle of such a trimmer to be conveniently adjusted.

Weed and grass trimmers using a flailing line for cutting purposes are widely used for many different kinds oftrimming, such as around obstacles and edging, where the plane occupied bythe rotating flail is differently oriented, sometimes horizontally, sometimes vertically, and sometimes in between these two positions.

One conventional trimmer comprises an engine or motor mounted on the outboard end of a handle shaft, with a drive head at the other end ofthe shaft. The flailing line is driven by a cable which passesth rough the handle shaft from the motortothe drive head.A grip on the handle shaft and an outwardly extending handle permitthe operatorto manoeuvre the plane of the rotating cutting line by tilting the drive head at whatever angle is necessary. In other conventional devices, both the motor and the drive head are located atthe distal end ofthe handle shaft.

Adifficulty in the use of such trimmers isthatthe weight of the engine makes manoeuvering and tilting at various angles rathertiring particularly when the engine and the drive head are at opposite ends ofthe appliance. The engine is usually mounted and balanced for use in one position relative to the handle, and a positivetorque must be applied to tilt the assembly. Also, when an internal combustion engine is used, it may not operate properly if tilted at excessively steep angles. The tilting can affect the flowoffuel which will disturb engine operation or even cause itto stop.It is advantageousforthe internal combustion engine to remain in one suitable orientation when the drive head is tilted at various angles relative to the engine to tiltthe cutting line. This also reduces operatorfatigue. When the motor is carried on the head, (in which case it is usually an electric motor), it is still useful to be able to change the head orientation relative to the handle so that the user can have the most effort-free grip on the assembly.

Therefore it is one object of the present invention to provide a trimmerwith a drive head which istiltably adjustable relative to a handle, and optionally also relative to an engine or motoron the handle end.

Another object ofthe invention is to provide a trimmer having a two-part handle shaft, of which one part is rotatable relative to the other, and the other part is fixed relative to a handle.

It is characteristic of the present invention that a tiltably adjustable head is provided by coupling a hollow handle shaft of a flailing line type trimmer by joining two parts. One part carries a grip, and might also carry an engine. The other part supports a drive headforspinningthecutting line, and in some devices, might also support a motorto turn the drive head. A coupling joins and secures the two parts of the handle shaft, and allows one part to be rotatably adjusted relative to the other part.

The coupling preferably is a split clamp fitting around and securely clamping the abutting ends ofthe two parts ofthe handle shaft. One part ofthe handle shaft has a circumferential groove which is engaged by a lip on the inside surface of one ofthe clamp halves. The clamp can be loosened to allowfor rotation without axial removal.

The other part of the handle shaft has a recess or hole engaged by a pin on one of the clamp halves which prevents any rotation. The lip and the pin prevent separation oftheir respective parts.

A sight port can optionally be provided so the user can be certain that the clamp is properly located.

These and otherfeatures ofthe invention should be fully understood from the following detailed description by reference to the accompanying drawings, in which: Fig. is a perspective view of a trimmer having a tiltably adjustable drive head according to the invention; Fig. 2 is an enlarged partial section; Fig. 3 is a sectional view at line 3-3 in Fig. 2; Fig. 4 is a sectional view at line 4-4 in Fig. 2; and Fig. 5 is a sectional view at line 5-5 in Fig. 2; The invention is best adapted for use on line trimmers ofthe type shown generally in Fig. 1. The line trimmerflails a line in a circular path to trim grass and weeds.In the illustrated embodiment it comprises an engine 10 mounted on the proximal end of a hollow handle shaft 12 through which there extends a cable 49 (Fig. 2) to a drive head 14. A handle 16 permits manoeuvering ofthe drive head and the flailing line.

The present invention permits easy adjustment of the angle of the drive head fortrimming around variously-oriented obstructions. This is accomplished by providing a hollow handle shaft in two parts, with one part being rotatable relative to the other part as shown in Figs. 2 to 5. These parts are joined and secured by a releasable coupling 18 which is hereinafterdescribed in greater detail.

The hollow handle shaft has a first part 20 and a coaxial second part 22. The handle shaft part 20 is joined to a hand grip 24 (Fig. 1) extending outwardly from the engine. The handle shaft part 22 is joined to the drive head 14at one end and is rotatablyjoined and secured in abutment with the handle shaft part 20 bythe releasable coupling 18.

This coupling 18 includes a split clamp secured around the abutting ends of the two handle parts by means of fasteners passing through mating flanges 28 and 30 on each end and opposite sides ofthe split clamp. A pin 32 mates with a recess 34 in the end of handle shaft part 20 to prevent rotation of the part 20 relative to the clamp, and therefore relative to the part 22. It also prevents axial separation ofthe part 20 from the clamp when the clamp is tightened.

The handle shaft part 22 has a circumferential groove 36 near its abutting end and a lip 38 on the inside surface of the coupling 28 engages in the circumferential groove 36. The lip 38 allowsthe handle shaft part 22 to rotate relative to the clamp, and therefore relative to the part 20 as shown by the arrow 40, but prevents separation ofthe part20from the coupling 18. The part 20 can be the "upper" part, and part 22 can be the "lower" part, or vice versa.

Snuglyfitting in the hollow ends of the handle shafts insidethecoupling l8aresolidcylindrical inserts42, 44to reinforce the shaft and resist compressive deformation when the clamp istightened. Holes 46 through the inserts 42,44 permit passage of a cable guide tube 48 which surrounds a cable 49 which extends from the engine 1 to the drive head 14. This cable 49 is kept in central alignment by a tube 48. The tube 48 is not needed in those types of weed trimmer where the motor is atthe distal end, and there is no cable to be supported and centred. However, the insert will be provided so thatthe clamp cannot crush the parts.

In use, the handle shaft part 22 is fitted in the coupling until it abuts the end ofthe handle shaft part 20 as viewed through a port 50 provided in the coupling. This also aligns the lip 38 with the groove 36 in the handle shaft part 22. The pin 32 will befitted into the recess 34 in the handle shaft part 20 before inserting the handle shaft part 22. Their correct abutment can be assured by looking through the port.

The fasteners are then tightened down securely so as to join and clamp thetwo handle shaft parts together.

Conveniently, the fasteners are bolt and nut combinations, with at least one of them adjacent the groove being a wing nut 52 so it can readily be loosened and tightened. The wing nut will betight- ened to fixthe position ofthe drive head. Angular adjustment eliminates the difficult and tiring task of tilting and holding the drive head in opposition to a torque exerted by the cutting head or by the drive head.

Thusthere has been described a releasable coupling device for a trimmer oftheflailing line type which permits easy adjustment of the drive head tilt angle.

This invention is not to be limited bythe embodimentshown in the drawings and described in the description, which is given by way of example and not of limitation, but only in accordancewiththescopeof the appended claims.

Claims

1. Aflailing line trimmer having a handle, a handle shaft, a drive head at the distal end ofthe handle shaft, an engine, and means operatively connecting the engine to the drive head, and characterised by releasable clamp meansforjoiningthehandletothe drive head wherebythe drive head may be rotated and held at a predetermined tilt angle with respectto the handle.

2. Aflailing linetrimmer according to claim 1 in which the releasable clamp means comprises: a first handle shaft part; a second handle shaft part; the drive head being attached to the end of one of said handle shaft parts and releasable coupling means coupling thefirstand second handle shaft parts; said releasable coupling means being constructed to allow one of said handle shaft parts to rotate independently of the other one.

3. Aflailing line trimmer according to claim 2 in which the releasable coupling means comprises a split clamp surrounding and securely clamping the ends of the first and second handle shaft parts in abutment with each other.

4. Aflailing line trimmer according to claim 3 in which one of the handle shaft parts has a circumferential groove; said split clamp having a lip on its inside surface in engagement with said g roove whereby said handle shaft part may rotate within said clamp and be restrained against axial removal.

5. Aflailing line trimmer according to claim 4 including stop means for restraining said other handle shaft part against rotation relative to said clamp, and against axial removal therefrom.

6. Aflailing linetrimmeraccordingtoclaim5in which said stop means comprises a recess near the end of said other handle shaft part; and a pin on said split clamp adapted to engage in said recess.

7. Aflailing linetrimmeraccordingtoanyofclaims 4, or 6 including releasable fastener means for releasing the clamping force of said split clamp for adjusting and resetting said drive head in an adjusted tilt position.

8. Aflailing line trimmer according to claim 7 in which said releasable fastener means comprises a wing nut adapted to be loosened and tightened against said clamp and thereby against said handle shaft part which has said circumferential groove.

9. Aflailing linetrimmeraccording to claim 1 in which the engine is mounted on the outboard end of the handle oftrimmer, said means operativelyjoining said engine to said drive head comprising a cable passing through said first and second handle shaft parts.

10. Aflailing linetrimmer according to claim 2 in which said coupling means includes a portforviewing the location ofthe abutting ends of said first and second handle shaft part in said coupling means.

11. Aflailing line trimmer according to claim 2 in which rigid inserts are fitted into hollow abutting ends of the upper and lower handle shaftsto resist compressive deformation by said coupling means.

12. Aflailing line trimmer according to claim 3 in which said coupling means includes a portforviewing the location ofthe abutting ends of said first and second handle shaft parts in said coupling means.

13. Aflailing linetrimmer constructed substantial- ly as hereinbefore described with reference to, and as shown in, the accompanying drawings.

13. Aflailing linetrimmer according to claim 9 in which rigid inserts are fitted into hollow abutting ends ofthe upper and lower handle shaftsto resist compressive deformation by said coupling means.

14. Aflailing line trimmer according to claim 13 in which a bearing is placed inside each of said insertsto journal said cable.

15. Aflailing linetrimmer constructed substantial- ly as hereinbefore described with reference to, and as shown in, the accompanying drawings.

New claims or amendmentsto claims filed on 7 Oct.

'83.

1. Aflailing line having a handle, a handle shaft, a drive head at the distal end ofthe handle shaft, an engine,and means operativelyjoining the engine to the drive head, and characterised by: releasable clamp means joining the handle to the drive head whereby the drive head may be rotated and held at a predetermined tilt angle with respect to the handle, the clamp means comprising a first handle shaft part and a second handle shaft part, the drive being head attached to the end of one of the handle shaft parts, and releasable coupling means for coupling the first and second handle shaft parts, the releasable coupling means being constructed to allow one of the handle shaft parts to rotate independently ofthe other and comprising a slit clamp surrounding and securely clamping the ends ofthe first and second handle shaft parts in abutment with each other.

2. Atrimmer according to claim 1 in which one of the handle shaft parts has a circumferential groove, and the split clamp has a lip on its inside surface in engagementwiththegroovewherebythe handle shaft part may rotate within the clamp and be restrained against axial removal.

3. Atrimmer according to claim 2 including stop means for restraining the said other handle shaft part against rotation relative to the clamp, and against axial removal therefrom.

4. Atrimmeraccording to claim 3 in which the stop means comprises a recess near the end of the other handle shaft part, and a pin on the split clamp is adapted to engage in the recess.

5. Atrimmer according to claim 2 including releasable fastener means for releasing the clamping force of the split clamp for adjusting and resetting the drive head in an adjusted tilt position.

6. Atrimmeraccording to claim in which the releasable fastener means comprises a wing nut adapted to be loosened and tightened against the clamp and thereby against the handle shaft part which has the circumferential groove.

7. Atrimmeraccordingto claim 1 in which the engine is mounted on the outboard end of the handle ofthe trimmer, the means operatively joining the engine to the drive head comprising a cable passing through the first and second handle shaft parts.

8. Atrimmeraccording to claim 1 in which the coupling means includes a portforviewing the location oftheabutting ends ofthefirstand second handle shaft part in the coupling means.

9. Atrimmeraccording to claim 1 in which rigid insertsarefitted into hollow abutting endsofthe upper and lower handle shaftsto resistcompressive deformation by said coupling means.

10. Atrimmeraccording to claim 1 in which the coupling means includes a portforviewing the location ofthe abutting ends ofthe first and second handle shaft parts in the coupling means.

11. Atrimmeraccordingtoclaim 7 inwhich rigid inserts are fitted into hollow abutting ends of the upper and lower handle shafts to resist compressive deformation by said coupling means.

12. Atrimmeraccordingto claim 11 inwhich a bearing is placed inside each of the inserts to journal the cable.