Seed drill

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the overall technical field of agricultural machinery. It relates more specifically to a seed drill comprising at least one metering device driven by a mechanism equipped with an input shaft, with a pinion and with a control handle.

2. Discussion of the Background

Such a mechanism is known to those skilled in the art. Indeed, the Amazonen-Werke company manufactures and markets a precision planter (Amazone ED brochure). This known machine comprises a chassis supporting elements for planting seeds in the ground and a respective hopper for each planting element. Between the hopper and a seed-planting element there is a distribution element driven by a drive mechanism. This known machine also comprises drive wheels arranged forward of the planting elements. The axis of rotation of each wheel is substantially horizontal and substantially perpendicular to the direction of forward travel of the seed drill. During work, said wheels run along the ground and, via transmission elements, drive the metering elements. Thus the seed, initially contained in the hopper, is first of all metered then planted in the ground by the coulters. Each drive mechanism is equipped with a clutch handle allowing the drive of the seed distribution element to be engaged and disengaged. Each drive mechanism is additionally equipped with a shear pin intended to protect the distribution element from any overload.

What happens is that when the drive torque on a seeding element becomes too high, said shear pin breaks and there is no longer drive to the distribution element. Once said shear pin has been replaced and prior to continuing with sowing the user usually wishes to check that the cause of the incident has been removed. To this end, it is possible for him to drive the distribution element manually by maneuvering said drive wheels.

Now, this maneuver is relatively awkward. Indeed the user has first of all to disengage the drive of the distribution elements which he is not wishing to check. Then, having maneuvered said drive wheels, he has once again to engage said drive. Such seed drills therefore exhibit an obvious drawback.

SUMMARY OF THE INVENTION

It is an object of the present invention therefore to overcome this drawback of the state of the art.

According to the present invention, said seed drill is one wherein said control handle is connected in terms of rotation to said input shaft. Thus, with such a seed drill, the operation of the metering element can be checked far more easily.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features of the invention, which are to be considered separately or in all feasible combinations thereof, will become apparent from the following description of a nonlimiting exemplary embodiment of the invention which is depicted in the appended drawings in which:

FIG. 1

depicts a simplified side view, in the work position, of a precision seed drill according to the invention,

FIG. 2

depicts a view in section on a different scale, of the drive mechanism with a control handle in the work position,

FIG. 3

depicts a view in section of the drive mechanism of

FIG. 2

in the disengaged position,

FIG. 4

depicts a view in section of the drive mechanism of

FIG. 2

in the safety position,

FIG. 5

depicts a part section on V of

FIG. 2

,

FIG. 6

depicts a part section on VI of

FIG. 2

,

FIG. 7

depicts a part section on VII of FIG.

4

.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The seed drill

1

depicted in

FIG. 1

comprises, in a way known to those skilled in the art, a chassis

2

, at least one device for storing seeds

3

, at least one metering device

4

and at least one planting element

5

.

During work, said seed drill

1

is moved, in a direction and sense of forward travel indicated by the arrow

6

, over ground that is to be sown. The seed, initially contained in said storage device

3

is conveyed to the planting element

5

. The seed is then buried in said ground using the planting element

5

. The metering device

4

, for its part, allows precise control over the amount of seed deposited in the ground. For its part, said chassis

2

allows said seed drill

1

to be connected to a motor vehicle

7

depicted in part.

In the remainder of the description, the ideas of “front” and “rear”, “in front of” and “behind” are defined with respect to the direction of forward travel

6

, and the ideas of “right” and “left” are defined when viewing said seed drill

1

from the rear in said direction of forward travel

6

.

In the exemplary embodiment depicted in

FIG. 1

, said seed drill

1

is of the “precision planter” type. To this end, said seed drill

1

comprises several seed planting elements

5

. Said planting elements

5

are arranged at substantially uniform spacings across the entire width of said chassis

2

. In a way known to those skilled in the art, each planting element

5

is connected to said chassis

2

and comprises a seed storage hopper

3

, a metering device

4

and a spout

8

. During work, each spout

8

digs a furrow in the ground and deposits seeds therein.

In a way known to those skilled in the art, each metering device

4

comprises a distribution disk (not depicted) equipped with cavities at regular intervals on a diameter. The distribution disk is driven in rotation about its axis

4

a

by means of a drive mechanism

10

. Each cavity receives a seed and drives it in rotation about the axis

4

a

to the ejection opening where the seed drops under gravity into said spout

8

and then into the soil. To guarantee uniform metering, the rotational speed of said drive mechanism

10

is advantageously proportional to the speed of forward travel of said seed drill

1

.

To this end, in the exemplary embodiment depicted, said drive mechanism

10

advantageously comprises two drive wheels

11

. During work, said wheels

11

run along the ground about an axis

11

a

which is substantially horizontal and substantially transversal to said direction of forward travel

6

. The rotational movement of said drive wheels

11

is transmitted to said metering device

4

in several stages. Specifically, said drive wheels

11

drive a primary spindle

1

a

of said seed drill

1

. The direction of said primary spindle

1

a

is substantially parallel to said direction of the axis

11

a

of said wheels

11

.

For its part, the primary spindle

1

a

transmits its rotational movement to a drive spindle

5

a

of said planting elements

5

. The direction of said drive spindle

5

a

is substantially parallel to said direction of the primary spindle

1

a.

The spindle

5

a

for its part drives a pinion

14

by means of a chain (not depicted). Thus, said pinion

14

is driven in rotation about an axis

14

a

at a speed that is proportional to the speed of forward travel of said precision seed drill

1

. The direction of said axis

14

a

is substantially parallel to said direction of the drive spindle

5

a.

Said axis

14

a

is advantageously coincident with the axis

4

a

of the distribution disk.

In the embodiment depicted in

FIGS. 2

to

4

, said drive mechanism

10

additionally comprises an input shaft

15

supporting said pinion

14

, a central hub

16

and a mechanical safety device

13

. Said distribution disk is connected to one end of said input shaft

15

. The other end of said input shaft

15

supports a centering nut

17

capped by a control handle

12

.

The control handle

12

has a complementary shape

18

matching the geometry of said pinion

14

. Seen in

FIG. 5

, said complementary shape

18

is advantageously hexagonal. Said control handle

12

is indexed in the work position by means of a spring-loaded indexing peg

19

. This is housed in an opening

20

formed, on one hand, in said control handle

12

and, on another hand, in said central hub

16

. Said hexagonal shape

18

allows said control handle

12

to be driven by said pinion

14

about the axis

14

a.

The rotational movement of said control handle

12

is transmitted to the input shaft

15

via a safety element

21

.

According to

FIG. 6

, the safety element

21

is housed in an orifice

22

passing through the following components: said control handle

12

, said central hub

16

and the input shaft

15

. The safety element

21

in combination with a compression spring

23

constitutes said mechanical safety device

13

.

FIG. 4

depicts a safety position in which said mechanical safety device

13

is activated. What happens is that when the maximum permissible drive torque for the input shaft

15

has been exceeded, the safety element

21

breaks and the distribution disk is no longer driven by means of said control handle

12

. The breakage of said safety element

21

allows said compression spring

23

to relax and to cause the translational movement, along the distribution axis

4

a,

of a set of components into abutment with said centering nut

17

. This set of components is formed of the following components: said pinion

14

, said central hub

16

, said spring-loaded indexing peg

19

and said control handle

12

. When the safety element

21

breaks, said control handle

12

advantageously positions itself in a safety position. During this translational movement, said pinion

14

immediately comes into contact with a roller

24

. As said roller

24

is connected to an electric switch

25

the passage of electric current is immediately shut off. The electric switch

25

also sends a signal to a receiving unit

26

. Said receiving unit

26

is preferably located in the cab of said motor vehicle

7

so as to trigger an alarm. Said roller

24

, the electric switch

25

and said receiving unit

26

advantageously constitute a warning device

9

. Said warning device

9

immediately informs the user of said seed drill

1

that there is a malfunction with said planting elements

5

. The alarm is advantageously of the audible and/or visual type. This alarm allows the user to act immediately on the defective planting element

5

having identified it from the position of said control handle

12

. Said control handle

12

is advantageously accessible and placed on the right-hand side of a planting element

5

and in a substantially horizontal plane, below said hopper

3

.

The safety element

21

produced in the example depicted by means of a shear bolt

21

preferably breaks into three pieces. Two of them, at the ends, are ejected through the orifice

22

. The third piece, situated in the middle and engaged in the input shaft

15

, can be extracted from said drive mechanism

10

via a removal hole

27

. Seen in

FIG. 7

, said removal hole

27

is preferably symmetric, with respect to said axis

14

a,

with said opening

20

that allows said control handle

12

to be indexed.

In this safety position, said control handle

12

remains indexed in said central hub

16

and will not be lost because of the incident that triggered the safety device. To return to a work position, all that is required is for said bolt

21

to be replaced, pushing on said control handle

12

to align the holes

22

in the following components: the input shaft

15

, said control handle

12

and said central hub

16

.

FIG. 3

depicts a position in which said control handle

12

is disengaged. In this position said spring-loaded indexing peg

19

is situated between said central hub

16

and the centering nut

17

. Said control handle

12

is no longer driven by said pinion

14

. For its part, said pinion

14

is still driven by said chain and rotates independently about said input shaft

15

. In this configuration, said distribution disk can be driven manually by said control handle

12

via said bolt

21

. Advantageously, when said control handle

12

has been disengaged, the user can thus check correct operation of the seed distribution disk. In this configuration, said pinion

14

does not come into contact with said roller

24

. The electric switch

25

does not send warning information to said receiving unit

26

.

The drive mechanism

10

and the precision seed drill

1

which have just been described are merely one exemplary embodiment and example of use which must not in any way restrict the field of protection defined by the claims which follow. Various modifications remain possible, particularly as regards the construction of the various elements or by substituting technical equivalents.

It is thus perfectly possible to use the drive mechanism

10

of the present invention on a seed drill.