GB2132865A

GB2132865A - Lawnmower

Info

Publication number: GB2132865A
Application number: GB08334192A
Authority: GB
Inventors: Raymond Auguste Despland; Marguerite Suzanne Berischi
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-23
Filing date: 1983-12-22
Publication date: 1984-07-18
Also published as: DE3346494A1; GB8334192D0; CH649191A5; FR2544582A1; GB2132865B

Abstract

The front of the frame 11 of the lawnmower is supported by steerable ground-engaging members 6 between which a cutting cylinder 1 is transversely mounted on the frame itself. The cylinder 1 is driven by pedals 32 via a chain 27 while a rear wheel 5 is drivable coy the pedals via a separate chain 25. <IMAGE>

Description

SPECIFICATION Lawnmower The present invention relates to a lawnmower actuated by the muscular power of the user.

It is already known to construct lawnmowers with rotatable cutting cylinders having helical blades, the cylinder being driven by the wheels of the lawnmower via gears, such lawnmowers simply being pushed by the user's arms.

Lawnmowers of this type are suitable when the grass to be cut is short but not when the grass is long and thick since the progress is often obstructed by tufts of grass which resist the force of the blades.

This grass becomes wedged between the helical blades and the counter-blade and, since it adheres to the ground by its roots, it has the effect of a tether, which immobilizes the mower.

When a problem of this sort arises, so as to disengage the mower, it is necessary to transmit increased power to the rotation of the blades in order that they can cut the grass causing the obstruction, but unfortunately the rotation of the cutting cylinder depends on the rotation of the wheels, which in turn depends on movement of the mower without sliding, this movement being very difficult since the mower is connected to the ground by the grass. Frequently the result is that the grass is torn out by the roots.

The lawnmower which is the subject of the present invention enables this disadvantage to be overcome; in this lawnmower the rotation of the cutting cylinder is not dependent on the bearing wheels, as in the known mowers which are pushed, but is obtained by means of a pedal assembly.

The present invention provides a lawn mower comprising a rigid frame on which a rear wheel, an operator's seat, a steering handle, a pair of groundengaging support members steerable by the steering handle via a steering linkage and supporting the front of the frame, a cutting cylinder mounted transversely of the frame between but independently of the steerable support members and having helical cutting blades, a counter-blade mounted transversely of the frame and cooperating with the cutting clinder, and a pair of pedals rigid in rotation with first and second drive sprockets having a common axis of rotation, the first sprocket driving the rear wheel via a first chain transmission, and the second sprocket driving the cutting cylinder via a second chain transmission.

It is thus possible to obtain cutting speed and power which are independent of the movement of the mower over the ground.

Since the cutting cylinder is not involved in the steering of the mower, the chain transmission driving the cylinder can be very simple. Furthermore, since the separate transmissions are used for the cutting cylinder and the rear wheel, it is easy to arrange the gearing ratio between them in such a way that the cylinder turns at least one (preferably five times) during each 10 cm of forward travel.

The ground-engaging support members may be skis. Over ground with an uneven surface, the skis are not greatly loaded (the weight of the person mowing rests predominantly by the rear wheel) and therefore the force with which the skis glide is less than the force with which small-diameter wheels would roll. In addition, when wheels penetrate a hole they lower the cutting cylinder such that it abuts against the ground, whilst skis, which span the holes, maintain the cutting cylinder at a normal level to a greater extent.

The mower may, if desired, be made in the form of a tricycle.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side-elevation of a pedaldriven lawnmower; and Figure 2 is a schematic plan view.

The lawnmower illustrated has a rigid frame 11 carrying a saddle 12. A substantially vertical steering shaft 13 is rotatably mounted in the frame 11 and carries handlebars 14. At the reartheframe carries a single drive wheel 5. At the front is carries a pair of steerable support members 6, each comprising a wheel 16 and a detachable ski 17. The members 6 are pivotally connected to the frame by vertical pivot shafts 18 and are also pivotably connected to opposite ends of a transverse steering rod 4 which is linked to the steering shaft 13 by a connecting rod 19.

A transverse shaft 21, rotatably mounted on the front of the frame in the region between the support members 6, carries a cutting cylinder 1 having helical blades which cooperate with a transverse counter-blade (not shown) also mounted on the frame.

In the middle the frame 11 is provided with a rotatable shaft 3 whose ends carry pedals 22. A first sprocket 23 for driving the rear wheel 5 and a larger second sprocket 24 for driving the cylinder 1 are fixed on the shaft 3. A first chain 25 passes round the sprocket 23 and a large sprocket 26 which is either rigid with the shaft of the rear wheel 5 or coupled to it by a disengageable clutch and, optionally, a speed reduction gear, thereby allowing the cutting cylinder to be rotated without advancing or only advancing slowly. A second chain 27 passes round the sprocket 24 and a smaller sprocket 2 which is welded to the shaft 21 rigid with the cylinder 1.

1. A lawnmower comprising a rigid frame on which are mounted a rear wheel, an operator's seat, a steering handle, a pair of ground-engaging support members steerable by the steering handle via a steering linkage and supporting the front of the frame, a cutting cylinder mounted transversely of the frame between but independently of the steerable support members and having helical cutting blades, a counter-blade mounted transversely of the frame and cooperating with the cutting cylinder, and a pair of pedals rigid in rotation with first and second drive sprockets having a common axis of rotation, the first sprocket driving the rear wheel via a first chain transmission, and the second sprocket driving

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Lawnmower The present invention relates to a lawnmower actuated by the muscular power of the user. It is already known to construct lawnmowers with rotatable cutting cylinders having helical blades, the cylinder being driven by the wheels of the lawnmower via gears, such lawnmowers simply being pushed by the user's arms. Lawnmowers of this type are suitable when the grass to be cut is short but not when the grass is long and thick since the progress is often obstructed by tufts of grass which resist the force of the blades. This grass becomes wedged between the helical blades and the counter-blade and, since it adheres to the ground by its roots, it has the effect of a tether, which immobilizes the mower. When a problem of this sort arises, so as to disengage the mower, it is necessary to transmit increased power to the rotation of the blades in order that they can cut the grass causing the obstruction, but unfortunately the rotation of the cutting cylinder depends on the rotation of the wheels, which in turn depends on movement of the mower without sliding, this movement being very difficult since the mower is connected to the ground by the grass. Frequently the result is that the grass is torn out by the roots. The lawnmower which is the subject of the present invention enables this disadvantage to be overcome; in this lawnmower the rotation of the cutting cylinder is not dependent on the bearing wheels, as in the known mowers which are pushed, but is obtained by means of a pedal assembly. The present invention provides a lawn mower comprising a rigid frame on which a rear wheel, an operator's seat, a steering handle, a pair of groundengaging support members steerable by the steering handle via a steering linkage and supporting the front of the frame, a cutting cylinder mounted transversely of the frame between but independently of the steerable support members and having helical cutting blades, a counter-blade mounted transversely of the frame and cooperating with the cutting clinder, and a pair of pedals rigid in rotation with first and second drive sprockets having a common axis of rotation, the first sprocket driving the rear wheel via a first chain transmission, and the second sprocket driving the cutting cylinder via a second chain transmission. It is thus possible to obtain cutting speed and power which are independent of the movement of the mower over the ground. Since the cutting cylinder is not involved in the steering of the mower, the chain transmission driving the cylinder can be very simple. Furthermore, since the separate transmissions are used for the cutting cylinder and the rear wheel, it is easy to arrange the gearing ratio between them in such a way that the cylinder turns at least one (preferably five times) during each 10 cm of forward travel. The ground-engaging support members may be skis. Over ground with an uneven surface, the skis are not greatly loaded (the weight of the person mowing rests predominantly by the rear wheel) and therefore the force with which the skis glide is less than the force with which small-diameter wheels would roll. In addition, when wheels penetrate a hole they lower the cutting cylinder such that it abuts against the ground, whilst skis, which span the holes, maintain the cutting cylinder at a normal level to a greater extent. The mower may, if desired, be made in the form of a tricycle. The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side-elevation of a pedaldriven lawnmower; and Figure 2 is a schematic plan view. The lawnmower illustrated has a rigid frame 11 carrying a saddle 12. A substantially vertical steering shaft 13 is rotatably mounted in the frame 11 and carries handlebars 14. At the reartheframe carries a single drive wheel 5. At the front is carries a pair of steerable support members 6, each comprising a wheel 16 and a detachable ski 17. The members 6 are pivotally connected to the frame by vertical pivot shafts 18 and are also pivotably connected to opposite ends of a transverse steering rod 4 which is linked to the steering shaft 13 by a connecting rod 19. A transverse shaft 21, rotatably mounted on the front of the frame in the region between the support members 6, carries a cutting cylinder 1 having helical blades which cooperate with a transverse counter-blade (not shown) also mounted on the frame. In the middle the frame 11 is provided with a rotatable shaft 3 whose ends carry pedals 22. A first sprocket 23 for driving the rear wheel 5 and a larger second sprocket 24 for driving the cylinder 1 are fixed on the shaft 3. A first chain 25 passes round the sprocket 23 and a large sprocket 26 which is either rigid with the shaft of the rear wheel 5 or coupled to it by a disengageable clutch and, optionally, a speed reduction gear, thereby allowing the cutting cylinder to be rotated without advancing or only advancing slowly. A second chain 27 passes round the sprocket 24 and a smaller sprocket 2 which is welded to the shaft 21 rigid with the cylinder 1. CLAIMS

1. A lawnmower comprising a rigid frame on which are mounted a rear wheel, an operator's seat, a steering handle, a pair of ground-engaging support members steerable by the steering handle via a steering linkage and supporting the front of the frame, a cutting cylinder mounted transversely of the frame between but independently of the steerable support members and having helical cutting blades, a counter-blade mounted transversely of the frame and cooperating with the cutting cylinder, and a pair of pedals rigid in rotation with first and second drive sprockets having a common axis of rotation, the first sprocket driving the rear wheel via a first chain transmission, and the second sprocket driving the cutting cylinder via a second chain transmission.

2. A lawnmower as claimed in claim 1, in which the ground-engaging support members comprise skis.

3. A lawnmower as claimed in claim 1 or 2, in which the first transmission includes a clutch for disengaging the rear wheel from the rotation of the pedals.

4. A lawnmower as claimed in any preceding claim, in which the second transmission comprises a driven sprocket which rotates coaxially with the cutting cylinder and a chain passing round the driven sprocket and the second drive sprocket.

5. A lawnmower as claimed in claim 4, in which the driven sprocket has a smaller diameter than the second drive sprocket.

6. A lawnmower as claimed in any preceding claim, in which the second drive sprocket has a larger diameter than the first drive sprocket.

7. A lawnmower as claimed in ay preceding claim, in which the gearing ratio ofthe first and second transmission is such that the cutting cylinder rotates more than once during each 10 cm of forward travel.

8. A lawnmower as claimed in claim 7, in which the cutting cylinder rotates five times during each 10 cm of forward travel.

9. A lawnmower substantially as described with reference to, and as shown in, the accompanying drawings.