GB2515058A

GB2515058A - Switch Actuator

Info

Publication number: GB2515058A
Application number: GB1310469.0A
Authority: GB
Inventors: William John Wainwright; Shaun Wealleans
Original assignee: Sumo UK Ltd
Current assignee: Sumo UK Ltd
Priority date: 2013-06-12
Filing date: 2013-06-12
Publication date: 2014-12-17
Also published as: GB201310469D0

Abstract

A switch actuator 3 for actuation of a switch controlling a material supply system in an agricultural distribution machine such as a seed drill of the type provided with a delivery system that is lowered toward the ground for use and that includes a hydraulically actuated raising and lowering system is described. The switch actuator comprises a hydraulic piston 11 and cylinder unit wherein the piston arranged to be slidable between a first position and a second position; a fluid input and output for hydraulic fluid adapted for fluid connection to the hydraulic circuit of a hydraulically actuated raising and lowering system of an agricultural distribution machine as above described; and a position sensor 14 to determine whether or not the piston is in the first position. A magnet 13 maybe mounted at the head of the piston. An agricultural distribution machine fitted with such an actuator and a method of fitment are also described.

Description

SWITCH ACTUATOR

The invention relates to a switch actuator for actuation of a switch controlling a material supply system in an agricultural distribution machine and to an agricultural distribution machine having a material supply system with such a switch actuator. The invention in particular relates to a switch actuator for actuation of a switch controlling a metering system in an agricultural seed drill and to a seed drill having a seed metering system with such a switch actuator.

In a variety of agricultural applications it is desirable to deliver material in particulate form onto or into a growing surface. Machines exist to perform this task with a variety of specific arrangements, but typically having in common a chassis mounted hopper, a material delivery system consisting of an elongate and typically laterally extending array of material delivery units contacting or adjacent rn the growing surface and provided with delivery outlets to output the particulate material in controlled manner to the growing surface, and a distribution system to transport the particulate material from the hopper to the outputs.

In use, the delivery system is caused to run across the ground surface and material is delivered in a distributed manner. When the machine is not in use, it may be desirable to raise the delivery system away from the ground for transportation, for example when a large field is being treated row by row, in order to move between rows. In such a configuration, it is desirable that particulate material is no longer supplied to the delivery outlets, as it would be wasted.

A particular example of this type of agricultural apparatus is a seed drill, and the invention is discussed hereinbelow in the context of such a seed drill, but the skilled person would appreciate that the principles of the invention could be applied to other analogous apparatus, for examp'e for the distribution of agricultural chemicals etc. A typical seed drill apparatus includes: a centrally mounted hopper; a delivery system comprising a laterally extending array of seed delivery units each provided with one or more discharge outlets; and a distribution system to pass seed from the hopper to the various seed delivery units.

The delivery system may comprise a laterally extending array of seed delivery units distributed along a supporting beam, for example comprising a laterally extending array of drill coulters. A delivery system may include various other apparatus to facilitate the seed distribution and planting process, for example including furrow devices such as discs to open a planting furrow, and other means to close and tamper the furrow after the seed is planted. The delivery system is typically ground engaging and mounted on a suitable chassis which is towed behind a tractor along a

field in use.

A distribution system supplies seed from the hopper to the outlets. It is for example a pneumatic distribution system.

Seed is drilled in successive rows. For transportation, for example at the end of each row before a new row is started, or at the end of a drilling operation, it is desirable to move the delivery system out of contact with the ground. Typically, provision is made for the delivery system to be raised and lowered hydraulically relative to the chassis for this purpose. Thus, the seed drill apparatus includes a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to a raising and lowering piston and cylinder unit actuatable to raise and lower the ground engaging seed delivery system relative to a supporting chassis, and hence lower it to the ground for use and raise it above the ground for transport It can be seen that it would not be desirable to distribute seed to the delivery system outlets when the drill is in the raised configuration. Such seed would be wasted.

Accordingly, a metering system is typically provided to allow the distribution of seed from the hopper to the delivery system to be interrupted. The distribution system thus includes a metering system having a switch which can be selectively operated to close and open the distribution system for the supply of seed.

Such a switch could be operated on user actuation. However) it has been recognised as desirable if the actuation of the switching means could be brought about automatically dependant upon whether the ground engaging delivery system is raised or lowered.

To avoid wasting seed it can be recognised that there is a need to disengage the distribution system and close off the metering system immediately the ground engaging delivery system leaves the ground. A switch actuation system that engaged and disengaged the metering system only once it was partly or fully raised would continue to meter seed to the seed discharge outlets for at least a period after the drill had disengaged from its drilling position on the ground, resulting in wastage.

Accordingly, a possible mechanism has been proposed to actuate a switch and engage and disengage the metering system based on a pair of devices which together serve as an actuator based proximity and for example as a proximity sensor, the devices located respectively on the part of the drill to be raised and lowered to engage with and disengage from the ground and on the chassis, and in such a position as to lie adjacent when the part to be raised and lowered is in the lowered position. Provision of such proximity sensors allows the actuation of the switch in the metering system the moment the ground engaging part of the drill begins to be raised, and thus allows effectively instantaneous closure of the metering system.

In accordance with such a system, metering of seed through the distribution system takes place only when the drill is fully lowered. This prevents loss of seed during the raising process, but introduces a new problem. It takes some time after the metering system is open for seed to be transported from the hopper to the seed discharge outlets at the drilling site. It is necessary to draw the drill for perhaps several metres across the ground before it starts to deliver seed effectively to the discharge outlets at the drilling site. There is the potential to leave several metres of each row unsown.

It is desiraNe to provide a switch actuator that mitigates some or all of the above disadvantages of prior art switch actuators that serve to selectively dose and open a metering system in an agricultura' delivery system such as a seed drill. It is particulady desirabk to provide a scilution which operates in conjunction with and requires only limited modification to existing hydraulic raising and towering mechanisms and existing distribution metering systems. It is particularly desirable to provide a system which lends itseLf to retrofit to existing apparatus.

Thus, in accordance with the invention in a first most general aspect, a switch actuator is provided for actuation of a switch controlling a materia' supply system in an agricultural distribution machine which is in particular a particulate material distribution machine such as a seed drill. The agricultural distribution machine is of the type provided with a delivery system that is lowered toward the ground for use and that indudes a hydraulically actuated raising and thwering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower the delivery system relative to a supporting chassis, and hence lower it to the ground for use and raise it above the ground for transport. The agricultural distribution machine is of the type provided with a metering system having a shut off switch to selectively close and open a supp'y of material such as particulate material such as seed to the dehvery system.

The switch actuator comprises a hydraulic piston and cylinder unit (where the term "cylinder" is used to mean the piston housing but not necessarily to imply a particular geometric shape) wherein the piston arranged to be slidable between a first position and a second position, a fluid input and output for hydraulic fluid adapted for fluid connection to the hydraulic circuit of a hydraulically actuated raising and lowering system of an agricultural distribution machine as above

S

described, and a position sensor to determine whether or not the piston is in the first position.

In use fitted on an agricultural distribution machine, the switch actuator is fitted in fluid communication with and for example fluidly in parallel with the hydraulic circuit of a hydraulically actuated raising and lowering system of an agricultural distribution machine. Because the hydraulic switch actuator of the invention is intended merely to be an actuation mechanism based on its position, and does not need to do substantive mechanical work, it is much smaller than the piston and cylinder units that are adapted to raise and lower the delivery system from and to the ground. Accordingly, essentially the instant hydraulic fluid is supplied to extend the main working pistons, the piston of the hydraulic switch actuator will move to its extended position, and similarly essentially the instant the reverse process is started, the piston of the hydraulic switch actuator will be fully withdrawn.

Thus, the piston essentially switches between its first and its second positions almost instantaneously once the hydraulic circuit is actuated to begin either the raising process or the lowering process. The key to the invention is that this means it is actuated asymmetrically relative to the raised or lowered position of the delivery system. It moves from one position to the other essentially as soon as the hydraulic system is engaged to begin a raising operation, but moves back essentially as soon as the hydraulic circuit is engaged to begin a lowering operation.

This asymmetry of action is exactly what is required by the particular problem to be solved. By provision of a suitable sensor to determine whether the piston of the hydraulic switch actuator is in the first position or not, this asymmetry can be exploited. The hydraulic switch actuator is actuated, and provides a detectable output capable of being employed to actuate a selectively switchable metering system, at the beginning of the raising operation, and also at the beginning of the lowering operation.

Thus, if the actuator is incorporated into a standard metering system as the means to effect actuation of the switched opening or closure of that metering system, it can serve to close the metering system essentially immediately the raising operation has started, as is desirable to avoid wastage of material once the delivery system begins to be raised) but it a'so can actuate opening of the metering system as soon as lowering commences. Metering of new material is not delayed until the delivery system is fufly lowered. Material is thus able to start passing through a distribution system which distributes it to the delivery system sooner, and is like'y to be made available at the delivery site sooner) mitigating or with appropriate design of delivery system flow rates even eliminating entirely the problem caused by delay of supply.

In use fitted on an agricukural distribution machine, the switch actuator is fitted in fluid communication with and for example fluidly in parallel with the hydraulic circuit of a hydraulically actuated raising and lowering system of an agricultural distribution machine. Thus in accordance with the invention in a further more complete aspect, a hydraulic system for an agricultural distribution machine comprises a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower a material delivery system relative to a supporting chassis, and a hydraulic switch actuator in accordance with the first aspect of the invention fluidly connected to the hydraulic circuit for exampk in parallel to the hydraulically actuated raising and lowering system. In a yet more compkte aspect an agricukural distribution machine comprises a delivery system mounted on a supporting chassis) a hydraulically actuated raising and thwering system including a hydraulic circuit to selectiv&y supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower a delivery system relative to a supporting chassis, and a hydraulic switch actuator in accordance with the first aspect of the invenUon fluidly connected to the hydraulic circuit for example in parallel to the hydraulically actuated raising and lowering system.

The material delivery system is for example an elongate and typically laterally extending plural array of material delivery units for example distributed along a supporting beam extending transversely of an intended direction of forward motion of the distribution machine so as in use to contact or be positioned adjacent to the growing surface and provided with delivery outlets to output the particulate material in controlled manner to a growing surface. The delivery machine further comprises a central storage hopper and a distribution system to transport the particulate material from the hopper to the outputs.

The agricultural distribution machine is for example a particulate material distribution machine such as a seed drill.

In this case the delivery system may comprise a laterally extending plural array of seed delivery units for example distributed along a supporting beam, for example comprising a laterally extending array of drill coulters. A delivery system may include various other apparatus to facilitate the seed distribution and planting process, for example including furrow devices such as discs to open a planting furrow, and other means to close and tamper the furrow after the seed is planted.

The delivery system is typically ground engaging and mounted on a suitable chassis frame which is for example towed behind a tractor along a field in use.

A distribution system supplies seed from a seed hopper to the outlets. It is for example a pneumatic distribution system.

It is a particular advantage of the present invention that it can be operated in conjunction with and requires only limited modification to existing hydraulic raising and lowering mechanisms and existing distribution metering systems. It is therefore particularly suited to incorporation into existing agricultural distribution machine designs, either as an after market modification or as a retrofit In possible further aspects of the invention, the invention comprises a kit of parts for an actuator of the first aspect of the invention to enable it to be retrofitted to an

B

existing agricultural distribution machine, and the invention comprises a method of the fitment of the same for example as an after market modification. The method comprises fluidly connecting an actuator in accordance with the first aspect to the hydraulic circuit for examp'e in parallel to the raising and lowering piston and cyllnder units, and preferably further functionally and for example electrically connecting the actuator into the metering system as the means to effect actuation of the switched opening or dosure of that metering system. Other features of the method may be inferred by ana'ogy from the description of the actuator and its operation.

In particuhr, there are a number of existing solutions invcilving existing metering systems and actuators that function based on sensing of r&ative position, but these are typically in the prior art based on sensing of the relative position of the raising and lowering system or of the raised or lowered delivery system relative to its supporting chassis. It isa particular advantage of the invention that it can be fitted as an alternative actuator into such an existing metering system to actuate a switch that serves to operate the metering system and to open and dose the distribution supply of material.

When so fitted the invention in its agricultural distribution machine aspect further comprises a delivery system provided with a metering system having a shut off switch to selectively close and open a supply of material to the delivery system, wherein the actuator is functionally and for example electrically or electromechanically connected into the metering system as the means to effect actuation of the switched opening or closure of that metering system.

The principal difference the invention offers over a system based on sensing of relative position of the raising and lowering system or of the raised or lowered delivery system relative to its supporting chassis is the point at which a detectable sensor response is generated. The switching system can otherwise be essentially as found in prior art systems. The switching system may for instance be electrical or electromechanical or mechanical. The actuator of the invention may serve to actuate the switching system directly or indirectly.

In a possilMe embodiment, the actuator is functionally linked and for examp'e dectricafly connected to an electrical switching system that acts to dose or open the metering system selectively based on the position of the actuator.

In a possilMe embodiment, the actuator is functionally linked and for examp'e electrically connected to an electromechanical switching system that acts to close or open the metering system selectively based on the position of the actuator.

It is an essentith feature of the invention that there is provided a position sensor to determine whether or not the cylinder is in the first position. This position sensor may itself be configured to open or close an electrical circuit directly and thus itself to act as a switch, or may be configured to provide an output for such an electrical circuit to operate an electrical or electromechanical switch that opens and closes the metering system.

In a convenient embodiment, the position sensor is embodied in a pair of complementary sensor modules which cooperate together to act as a proximity sensor. For example one may be located at or about the head of the piston, and the other may be located proximal to the position of the head of the piston when the piston is in its first position. Thus, the two sensor modules are closdy adjacent when the piston is in its first position and spaced apart when it is in its second position. The piston is thus enabled to act as a switch actuator.

In a possible embodiment, the piston and cylinder is mounted in a housing bracket aliowing the piston to slide relative to the housing. A first sensor module may then be located at or about the head of the piston a second sensor modu'e may be located in or on the housing proximal to the position of the head of the piston when the piston is in its first position.

In a possible embodiment the metering system is configured to be open with material flowing when the sensor modules are proximate.

In this embodiment, the hydraulic switch actuator is configured such that as the lowering mechanism actuates) the piston moves essentiafly immediately to the first position) bringing the sensor modules together. As the raising mechanism actuates) the piston moves essentially immediately away from the first position, bringing the sensor modu'es apart A suitable simp'e arrangement of sensor modules could be a magnet and a detector) for example a magnet being provided at or about the head of the piston and a detector being provided in the housing proximal to the position of the head of the piston when the piston is in the first position.

Such an arrangement allows the switch actuator to embody essentially similar principles to those employed in the prior art. As in the prior art, actuation is by relative position. However) unlike the prior art) actuation is not by relative position of chassis and distribution system, but by r&ative position of the hydraullc actuator piston in the housing. The novel feature is the hydraulic switching actuation. This overcomes the problems common to all prior art systems that are based on position of the raising and lowering system or of the delivery system relative to the chassis.

In such systems the metering system either disengages too late on raising or reengages too tate on Thwering. The hydraulic actuator switch of the present invention provides an asymmetric actuation in a manner which is desirable in operation, and does so automatically in conjunction with the existing hydraulic system.

The invention will now be described by way of example only with reference to Figures ito 4 of the accompanying drawings in which: Figure 1 is a schematic representation of an embodiment of the switch actuator of the present invention shown in position in conjunction with the lift and lower 1l hydraulic circuit of a conventional agricultural distribution machine such as a seed drill; Figure 2 shows the ram of Figure 1 in its drilling position; Figure 3 shows the ram of Figure 1 in its retracted position; Figure 4 shows the ram in exploded form.

For the purposes of the illustrative embodiment) operation is discussed in the context of metering of seed from the hopper to the drilllng system of a seed drill apparatus. The embodiment is discussed in the context of the starting and stopping of seed supply via the hydraulic ram.

The traditional method to control metering of seed to a seed drill during operation was to provide a metering land wheel that took control of the speed. When the machine was lifted from the ground the wheel would stop and the seed would stop being metered.

Seed drilling operations have become more automated with the introduction of electronics and radar control of the speed. More usually now, a sensor is used to start and stop the seed metering. On a trailed seed drill the sensor is generally positioned on the chassis near the back axle, with a magnet positioned on the axle.

When the axle of the drill is lifted the two part company, the circuit is broken and seed stops being metered. When the axle is lowered completely, the circuit is reformed and the seed is again metered.

Stopping the supply the moment the axle is lifted is desirable as it prevents wastage.

Re-starting the supply only when the axle is lowered completely is not necessarily desirable, as modern drilling machines are long and the seed takes time to get to the drilling apparatus, so that the machine will travel a distance of several meters without seeding.

The invention shown in the illustrated embodiment solves this problem in an admirably compatible manner, in that it still uses a magnet and sensor, and so fits readily into existing control circuitry, but operates asymmetrically to stop metering of seed the moment the axle is raised, but to start it again the moment ftc lower process starts, thus giving time for the seed to reach the coulters at around the point they engage with the soil.

The embodiment uses a small hydraulic ram 3 which is placed into the lift and lower hydraulic circuit alongside the main lift and lower rams 1. The hydraulic ram comprises a conventional piston and cylinder arrangement mounted in a housing 12. A magnet 13 is mounted at the head of the ram piston 11. This arrangement allows the magnet 13 to move relative to the housing bracket 12. A sensor 14 is provided at one end of the housing bracket.

With the piston fully extended (Figure 2] the magnet 13 is in close proximity to the sensor 14. If the actuator of the invention is fitted into a conventional magnet and sensor based actuation circuit, it mirrors in this configuration the condition for creating the circuit and seeding is possible.

When the piston is withdrawn, the sensor and magnet part company. Again, if the actuator has been fitted to a conventional magnet and sensor based actuation circuit, this mirrors the action of magnet and sensor with the axle raised, and seed stops being metered.

The key to the invention is that the movement of the hydraulic ram does not symmetricafly reflect the juxtaposition of the chassis and axle. With the ax'e lowered completely, the magnet and sensor are in close proximity in the first position represented in Figure 2, and thus the system mirrors the prior art system above described. The moment the hydraulic system begins to raise the axle, because the ram of the actuator of the invention is so much smaller than the mechanical rams that serve to lift and lower) the piston is withdrawn essentially immediately to the second position represented in Figure 3. The magnet and sensor are no longer in proximity, and metering stops essentially immediately in like manner to the prior art above described. However, the same hydraulic considerations mean that the moment the hydraulic system is actuated to begin the lowering process, the ram is actuated to revert to the first position represented in Figure 2. Thus, whereas in prior art systems based on juxtaposition of sensors on the chassis and axel the circuit is not closed until the axel is essentially fully lowered, in a system in accordance with the invention the circuit may be closed essentially immediate'y the lowering process begins) thus giving time for the seed to reach the coulters by the time they have engaged with the soil.

Claims

CLAIMS1. A switch actuator for actuation of a switch controlling a material supply system in an agricultural distribution machine of the type provided with a delivery system that is lowered toward the ground for use and that includes a hydraulically actuated raising and lowering system, the switch actuator comprising: a hydraulic piston and cylinder unit wherein the piston arranged to be slidable between a first position and a second position; a fluid input and output for hydraulic fluid adapted for fluid connection to the hydraulic circuit of a hydraulically actuated raising and lowering system of an agricultural distribution machine as above described; and a position sensor to determine whether or not the piston is in the first position.
2. A switch actuator in accordance with claim 1 provided in combination with an agricultural distribution machine provided with a delivery system that is lowered toward the ground for use and that includes a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower the delivery system relative to a supporting chassis, and fluidly connected in fluid communication with the hydraulic circuit of the hydraulically actuated raising and lowering system.
3. A switch actuator in accordance with claim 2 connected fluidly in parallel with the hydraulic circuit of a hydraulically actuated raising and lowering system.
4. A switch actuator in accordance with one of claims 1 to 3 provided in combination with an agricultural distribution machine having a central material store and a delivery system and provided with a metering system having a shut off switch to selectively close and open a supply of material to the delivery system wherein the actuator is functionally incorporated into the metering system as the means to effect actuation of the switched opening or closure of that metering system.
5. A switch actuator in accordance with claim 4 wherein the actuator is electrically connected to an electrical or electromechanical switching system that acts to close or open the metering system selectively based on the position of the actuator.
6. A switch actuator in accordance with claim 5 wherein the position sensor is itself configured to open or close an electrical circuit directly and thus to act as a switch that opens and closes the metering system.
7. A switch actuator in accordance with claim S wherein the position sensor is electrically connected to provide an actuating output for an electrical circuit to operate an electrical or electromechanical switch that opens and closes the metering system.
8. A switch actuator in accordance with any preceding claim wherein the position sensor is embodied in a pair of complementary sensor modules which cooperate together to act as a proximity sensor.
9. A switch actuator in accordance with claim B wherein one of the sensor modules is located at or about the head of the piston, and one of the sensor modules is located proximal to the position of the head of the piston when the piston is in its first position.
10. A switch actuator in accordance with claim 9 wherein the piston and cylinder is mounted in a housing allowing the piston to slide relative to the housing, a first sensor module is located at or about the head of the piston a second sensor module is located in or on the housing proximal to the position of the head of the piston when the piston is in its first position.
11. A switch actuator in accordance with one of claims B to 10 wherein the actuator is configured such that when in use on a distribution machine, as the lowering mechanism of the distribution machine actuates, the piston moves essentially immediate'y to the first position, bringing the sensor moduks together and such that as the raising mechanism of the distribution machine actuates, the piston moves essentiafly immediately away from the first position, bringing the sensor modules apart.
12. A switch actuator in accordance with one of claims B to 11 wherein the pair of sensor modules comprise a magnet and a detector.
13. A switch actuator in accordance with claim 12 wherein a magnet is provided at or about the head of the piston and a detector is provided in a position proximal to the position of the head of the piston when the piston is in the first position.
14. A hydraulic system for an agricultural distribution machine comprising a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower a delivery system relative to a supporting chassis, and a hydraulic switch actuator in accordance with any preceding claim fluidly connected to the hydraulic circuit.
15. An agricultural distribution machine comprising a delivery system mounted on a supporting chassis, a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower a delivery system relative to a supporting chassis, and a hydraulic switch actuator in accordance with any preceding claim fluidly connected to the hydraulic circuit.
16. An agricultural distribution machine in accordance with claim 15 further comprising and a delivery system provided with a metering system having a switch to selectively close and open a supply of material to the delivery system wherein the actuator is functionally connected into the metering system as the means to effect actuation of the switched opening or closure of that metering system.
17. A kit of parts for an actuator in accordance with one of claims 1 to 13 adapted to be retrofitted to an agricultural distribution machine.
18. A method of fitment of an actuator to an agricultural distribution machine comprising a hydraulically actuated raising and lowering system including a hydraulic circuit to selectively supply pressurised fluid to one or more raising and lowering piston and cylinder units actuatable to raise and lower a delivery system relative to a supporting chassis, the method comprising fluidly connecting an actuator in accordance with one of claims 1 to 13 to the hydraulic circuit
19. The method of claim 18 applied to an agricultural distribution machine comprising delivery system provided with a metering system having a switch to selectively close and open a supply of material to the delivery system, the method comprising the further step of functionally connecting the actuator into the metering system as the means to effect actuation of the switched opening or closure of that metering system.