IMPLEMENT-CARRYING VEHICLE

Abstract: An implement-carrying vehicle (10) with a front-mounted implement is provided with a lifting device (14) operable by the driver of the vehicle, for lifting the implement (12) from a lowered working position to a raised transport position and lowering the implement from the transport position to the working position. The lifting device (14) has a lever mechanism (16) with a first lever arm (17) coupled to the implement (12), and a second lever arm (18) operable by the driver. The lever mechanism (16) is pre-stressed by means of a spring member (33) in a swinging direction corresponding to raising the implement (12), said spring member being connected to the lever mechanism (16) at a point that is movable for adjustment of the moment arm of the spring force exerted on the lever mechanism by the spring member (33).

Description: IMPLEMENT-CARRYING VEHICLE The present invention relates to an implemen -carrying vehicle with a front -mounted implement, particularly a ride-on lawnmower with a front-mounted grass-cutting unit, which vehicle is provided with a lifting device operable by the driver of the vehicle, for lifting the implement from a lowered working position to a raised transport position and lowering the implement from the transport position to the working position, said lifting device having a lever mechanism with a first lever arm coupled to the implement, and a second lever arm operable by the driver. A known vehicle of this type is shown in Figs 1 and 2 which are schematic side views and show the front part of a ride-on lawnmower with a grass-cutting unit in lowered and raised position, respectively. The ride-on lawnmower shown in Figs 1 and 2 has a chassis 1 supported by wheels, a driver's seat 2 secured to the chassis, a steering wheel 3 and a front-mounted grass-cutting unit 4. The grass-cutting unit 4 is pivot- ably supported on the front-wheel axle 5 of the lawn- mower and can be swung between a lowered working position (Fig. 1) and a raised transport position (Fig. 2) . The ride-on lawnmower is also provided with a lifting device 6 operable by the driver for raising and lowering the grass-cutting unit 4. The lifting device 6 consists of a lever mechanism that can be swung about the axis of a shaft 7 parallel to the wheel axle 5. The lever mechanism has a forward lever arm 6a which is coupled to the grass-cutting unit 4, and a rear lever arm 6b rigidly joined to the forward lever arm 6a and forming substantially a right angle with the forward lever arm 6a. The rear lever arm is provided with an operating handle 8 at its rear end. When the lifting device 6 is in a swinging position corresponding to the working position of the grass-cutting unit 4 (Fig. 1) , the handle 8 of the rear lever arm 6b is, as shown in Fig. 1, located some considerable dis- tance from the driver's seat 2, making it troublesome for the driver to reach from the driver' s seat 2. To raise the grass-cutting unit 4 with the aid of the lever mechanism the driver must assume a rather complicated and uncomfortable position, making it difficult to raise the grass-cutting unit, particularly if this is of a large and therefore heavy type . One object of the present invention is therefore to provide an implement -carrying vehicle in which the lifting device can be operated more easily and the force required to lift the implement can be adjusted to be less dependent on the weight of the implement . In accordance with the present invention this object is achieved with an implement -carrying vehicle of the type described in the introduction which is characteris- ed in that the lever mechanism is pre-stressed by means of a spring member in a swinging direction corresponding to raising the implement, said spring member being connected to the lever mechanism at a point that is movable for adjustment of the moment arm of the spring force exerted on the lever mechanism by the spring member. In a suitable embodiment the spring member is a gas spring . In a preferred embodiment the spring member is connected to the second lever arm of the lever mechanism. The spring member is preferably connected to the second lever arm of the lever mechanism by means of a connecting part which, to enable adjustment of said moment arm, is displaceable along a spindle extending along the second lever arm and joined thereto. In a preferred embodiment the connecting part has a threaded through bore and the spindle is threaded, extends through the bore and is in such threaded engagement with the connecting part that the connecting part is moved along the spindle when this is turned. The lifting device is preferably operable by means of a foot pedal secured to the second lever arm. The invention will now be described in more detail with reference to the accompanying drawings. Figs 1 and 2 are schematic side views and show the front part of the known ride-on lawnmower described above, with a grass-cutting unit in lowered and raised position, respectively. Figs 3 and 4 are schematic sides views showing the front part of a ride-on lawnmower in accordance with the invention, with a grass-cutting unit in lowered and raised position, respectively. Figs 5 and 6 show the lifting device of the ride-on lawnmower on a larger scale and in the positions shown in Figs 3 and 4, respectively. Figs 7 and 8 correspond to Figs 5 and 6, respectively, but show a gas spring included in the lifting device in a different position. Figs 9 and 10 are views in perspective, seen obliquely from the front and obliquely from behind, respectively, and reveal the lifting device of Figs 7 and 8 in a position corresponding to the lowered and the raised position, respectively, of the grass-cutting unit. The ride-on lawnmower 10 shown in Figs 3 and 4 has a chassis 11 supported by wheels, and supports a front - mounted grass-cutting unit 12. The grass-cutting unit 12 is pivotably supported on the front -wheel axle 13 of the ride-on lawnmower 10 and can be swung between a lowered working position (Fig. 3) and a raised transport position (Fig. 4) . The ride-on lawnmower 10 is also provided with a lifting device 14 operable by the driver for raising and lowering the grass-cutting unit 12. The grass-cutting unit 12 is coupled to the lifting device 14 by means of a link arm 15. The lifting device 14 comprises a lever mechanism 16 consisting of a forward lever arm 17 which is coupled to the grass-cutting unit 12 via the link arm 15, and a rear lever arm 18. Both the lever arms 17 and 18 are non-rota- tionally joined to a shaft 19 which is pivotably journal- led in a shaft attachment 20 rigidly joined to the chassis 11. The attachment 20 is U-shaped and the shaft 19 is rotatably journalled at its ends in the legs 20a and 20b of the attachment 20, by bearings 21a and 21b. The rear lever arm 18 is substantially Y-shaped and its two Y-legs 18a and 18b, which are parallel to each other, are non-rotationally joined to the shaft 19 on each side of the forward lever arm 17. A foot pedal 22 for operating the lever mechanism 16 is secured to the Y-base 18c of the rear lever arm 18. A substantially U-shaped yoke 23 with a long web section 23a and relatively short legs 23b and 23c, extends along one Y-leg 18a of the rear lever arm 18, outside this, and is non-rotationally joined by its front leg 23b to the shaft 19. A threaded spindle 24 extending along the Y-leg 18a is rotatably journalled in the two legs 23b and 23c of the yoke 23. The spindle 24 is provided at its forward end with a female hexagonal head 25 resting against the outside of the forward yoke leg 23b via a washer 26. At the rear end of the spindle 24 a locking nut 27 is non-rotationally joined to the spindle and rests against the outside of the rear yoke leg 23c via a washer 28. A connecting part 29 with a threaded through bore is arranged on the spindle 24. The spindle 24 extends through this bore and is in such threaded engagement with the connecting part 29 that the connecting part is moved along the spindle when this is turned. The spindle 24 is turned with the aid of a tool (not shown) that is brought into engagement with the female hexagonal head 25 of the spindle. The connecting part 29 rests against the web section 23a of the yoke 23 via a sliding plate 30 secured to the lower side of the connecting part. A yoke 31 is arranged above the connecting part 29 and pivotably joined thereto by means of a pin 32 extend- ing through the connecting part, parallel with the shaft 19. A gas spring 33 is arranged between an attachment plate 11' rigidly joined to the chassis 11, and the yoke 31. The piston rod 34 of the gas spring 33 is rigidly joined to the yoke 31 and its cylinder 35 is pivotably joined to the attachment plate 11' by means of an attachment lug 36 arranged at the upper end of the cylinder, and a pin 37 extending through the lug, which pin is parallel to the pin 32 and the shaft 19. The gas spring 33 is a compression spring and thus pre-stresses the lever mechanism 16 in a swinging direction corresponding to raising the grass-cutting unit 12. The force with which the foot pedal 22 must be depressed in order to raise the grass-cutting unit 12 from the working position to the transport position is thus reduc- ed. The extent to which the pedal force required is reduced is dependent on the moment arm of the spring force exerted by the gas spring 33, i.e. the distance between the connecting part 29 and the pivot axle of the lever mechanism 16, defined by the axis of the shaft 19. This moment arm can be adjusted by moving the connecting part 29 along the spindle 24 and, as mentioned, this movement is achieved by turning the spindle 24. Figs 5 and 6 show the connecting part 29 in a forward position, in which the above-mentioned lever arm is shortest and which thus defines a setting position for the gas spring 33 that is suitable for a relatively light grass-cutting unit 12. Fig. 5 shows the lever mechanism 16 in a swinging position corresponding to the lowered working position of the grass-cutting unit 12, and Fig. 6 shows it in a swinging position corresponding to the raised transport position of the grass-cutting unit 12. Figs 7 and 8 show the connecting part 29 in a rearward position in which the above-mentioned lever arm is longest and which thus defines a setting position for the gas spring 33 that is suitable for a heavy grass-cut- ting unit 12. Fig. 7 shows the lever mechanism 16 in a swinging position corresponding to the lowered working position of the grass-cutting unit 12, and Fig. 8 shows it in a swinging position corresponding to the raised transport position of the grass-cutting unit 12. The invention is naturally not limited to the embodiment described above, but can be modified in various ways within the scope of the appended claims. The ride- on lawnmower 10 may, for instance, be an implement-carrying vehicle of some other type and/or be provided with an implement other than a grass-cutting unit, such as a snow-throwing unit, a street -sweeping unit, a moss-stripping unit or the like. The gas spring 33 may be exchanged for some other suitable spring member which naturally need not be a compression spring member, nor need it be connected to the rear lever arm 18. The important thing is for the spring member to pre-stress the lever mechanism 16 in a swinging direction corresponding to raising the implement.

Claims: CLAIMS 1. An implement-carrying vehicle (10) with a front- mounted implement (12), particularly a ride-on lawnmower with a front-mounted grass-cutting unit, which vehicle (10) is provided with a lifting device (14) operable by the driver of the vehicle, for lifting the implement (12) from a lowered working position to a raised trans- port position and lowering the implement from the transport position to the working position, said lifting device (14) having a lever mechanism (16) with a first lever arm (17) coupled to the implement (12) , and a second lever arm (18) operable by the driver, c h r - a c t e r i s e d in that the lever mechanism (16) is pre-stressed by means of a spring member (33) in a swinging direction corresponding to raising the implement (12), said spring member being connected to the lever mechanism (16) at a point that is movable for adjustment of the moment arm of the spring force exerted on the lever mechanism by the spring member (33) . 2. A vehicle as claimed in claim 1, c h a r a c t e r i s e d in that the spring member (33) is a gas spring . 3. A vehicle as claimed in claim 1 or claim 2, c h a r a c t e r i s e d in that the spring member (33) is connected to the second lever arm (18) of the lever mechanism (16) . 4. A vehicle as claimed in claim 3, c h a r a c - t e r i s e d in that the spring member (33) is connected to the second lever arm (18) of the lever mechanism (16) by means of a connecting part (29) which, to enable adjustment of said moment arm, is displaceable along a spindle (24) extending along the second lever arm (18) and joined thereto. 5. A vehicle as claimed in claim 4, c h a r a c t e r i s e d in that the connecting part (29) has a threaded through bore and that the spindle (24) is threaded, extends through the bore and is in such threaded engagement with the connecting part (29) that the connecting part is moved along the spindle (24) when this is turned. 6. A vehicle as claimed in any one of claims 1-5, c h a r a c t e r i s e d in that the lifting device (14) is operable by means of a foot pedal (22) secured to the second lever arm (18) .

Inventors: JOHANSSON SOEREN, JOHANSSON, SOEREN
Applicants: JOHANSSON SOEREN, STIGA AB, JOHANSSON, SOEREN
Application year: 2000
Main classification: A01B59
IPC codes: A01B59, A01B73, A01D34