Device For Automatic Self-levelling Of The Body Of A Threshing-harvesting Machine

Abstract

Automatic self-levelling of the body of a threshing-harvesting machine is effected by a device which is sensitive to the operation of respective magnetic float switches located in respective interconnected liquid-containing vessels positioned on opposite lateral sides of the body. Each vessel contains two laterally spaced apart float switches connected to electro-valves in an hydraulic circuit for self-levelling actuators so that when either of the laterally outer float switches is operated the actuators are supplied with part of the hydraulic fluid output from a pump to effect correction and when either of the inner switches is operated at a greater angle of inclination, the actuators are supplied with the full pump output to effect rapid levelling. An alarm is operated automatically in the event of excessive inclination of the body of the machine.

Description

BACKGROUND OF THE INVENTION

This invention relates to a device for effecting automatic levelling threshing-harvesting machines.

It is known to provide such machines with devices which maintain the body of the threshing machine upright independently of unevenness of the ground on which the wheels of the machine rest.

The body of such machines is hinged in its center for rocking movement about axles which are formed by double levers interconnected in deformable parallelogram linkages, the body being kept upright by hydraulic double-acting rams.

The cutting platform of the machine is kept substantially parallel to the ground by means of other devices which form a connection between the platform itself and the front axle of the machine.

An object of this invention is to provide a device for the automatic levelling of the body of such machines, which is of simple, strong and economical construction, precise and safe in operation and of high functional efficiency.

Another object of this invention is to provide a device of the above mentioned type, which allows automatic levelling at different rates as a function of the inclination taken of the body to the horizontal and which allows at the same time manual emergency operation for quick straightening.

A further object of this invention is to provide a device as aforesaid which has high sensitivity and precision of control and is able to cease operation immediately in the event of an excessive inclination of the body to the horizontal, initiating an alarm signal.

SUMMARY OF THE INVENTION

The present invention accordingly provides a device for effecting automatic levelling of the body of a threshing-harvesting machine, characterized in that the device comprises two inter-communicating liquid-containing vessels, mounted on opposite lateral sides of the body, first and second magnetic level-sensitive switches placed at different lateral positions or heights in each vessel and adapted to operate selectively in response to lateral inclinations of the body of the machine to the horizontal by more than a first and more than a second angle respectively, the second angle being greater than the first, the first switches being arranged to operate a double acting first electro-valve in a feed circuit for two hydraulic levelling actuators and the second switches being arranged to operate a second electro-valve, which normally reduces the flow of hydraulic fluid under pressure from a pump to the actuators so that the latter are supplied with the full pump flow to effect rapid levelling, means for operating the two electro-valves manually and means operative to prevent the two electro-valves from operating in the event of an excessive inclination of the said body, and to activate an alarm device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic front view of a threshing-harvesting machine provided with an automatic body levelling device according to one embodiment of the invention;

FIG. 2 is an hydraulic circuit diagram of the device, and

FIG. 3 is an electric circuit diagram of the device.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to FIG. 1, reference numeral 1 indicates the body of a threshing-harvesting machine (drawn without its cutting platform). The body 1 has a central front appendage 1a which is pivotally connected to a front axle 3 by means of a center pivot 2 for rocking movement about a central longitudinal axis.

The body 1 is formed with two lateral brackets 4, 4' which provide pivotal support for the cylinders 5, 5' of the respective hydraulic double-acting rams, the piston rods 6, 6' of which are pivotally connected by means of respective joints 7, 7' to opposite ends of the axle 3.

As illustrated in FIG. 2, the ram cylinders 5, 5' are supplied from an hydraulic pump 8, which draws hydraulic fluid from a tank 9 and supplies the fluid under pressure, through an adjustable spring-loaded pressure relief valve 10, to a conduit 11 which subdivides into two branch conduits 12 and 13. The branch conduit 12 supplies the fluid under pressure to a double-acting first solenoid-operated electrovalve 14. The valve 14 has a first pair of output conduits 15, 15' connected to opposite ends of the respective cylinders 5, 5' and a second pair of output conduits 16, 16' connected to the other ends of said cylinders, so that the conduits 15 and 16' are connected to the lower ends of the cylinders 5 and 5' and the conduits 15' and 16 are connected to the upper ends of the cylinders 5' and 5 respectively.

The branch conduit 13 is connected through an adjustable flow restrictor 17 to a single-acting second solenoid-operated electro-valve 19 which, in its rest condition, connects the output of the restrictor 17 to the tank 9 to ensure that substantially half the output flow from the pump 8 reaches the first electro-valve 14.

FIG. 3 illustrates the electric circuit of the device. Two intercommunicating vessels 19, 19' are fixed laterally to the body 1 of the machine and communicate through a conduit 19a containing a throttling valve 19b. Each vessel 19 and 19' contains two magnetically operated float switches 20, 21 and 20', 21' respectively co-operating with respective magnetic relays 22, 23 and 22', 23'. The two switches 20, 21 and 20', 21' in each vessel 19 and 19' are spaced apart laterally so that the two outermost switches 20 and 20' are more sensitive to lateral inclination of the body 1 than the two innermost switches 21 and 21'. Alternatively, the two switches 20, 21 and 20', 21' may be arranged at different heights in each vessel.

Current is supplied through a lead 24, a fuse 24a and a master switch 25 to a pilot lamp 26, a relay 27 and an interruptor 28 connected in its turn with a flasher lamp 29 and an optical and acoustic alarm device 30.

A micro-switch 31 is operable manually by means of an emergency lever 32, pivoted at 33 and adapted to act mechanically on the double-acting first electro-valve 14. Two limit micro-switches 34, 34' are arranged to be operated directly by the axle 3 when the lateral inclination of the body 1 exceeds the maximum inclination at which the automatic control device is allowed to operate.

The operation of the device is as follows:

When the body 1 of the machine reaches a lateral inclination to the horizontal between 4.degree. and 10.degree. the lower of the two laterally outer float switches 20 and 20' is operated by the buoyancy effect of the liquid in the vessel 19 or 19' to close the circuit in which it is connected and operate the first electro-valve 14 so as to cause the latter to direct the hydraulic fluid into opposite ends of the two cylinders 5 and 5' in a sense such as to counter the inclination of the body 1 of the machine and thereby bring about levelling of the latter. The flow of fluid into the two ram cylinders 5, 5' is substantially half the output flow of the pump 8, and therefore the levelling speed is slow.

When the body 1 of the machine has reached an upright position, the float switch which has been operated reopens the circuit and the levelling action of the device stops.

The fluid transfer rate from one vessel to the other is controlled by the throttling valve 21 so that the damping action of the liquid allows the body of the machine to reach an exactly upright position and not a position inclined to the horizontal.

When the body 1 of the machine assumes an inclination to the horizontal greater than 10.degree., both magnetic float switches 20 and 21 or 20' and 21' which are in the lower vessel 19 or 19' close, energizing simultaneously both the electro-valves 14 and 18. The electro-valve 18 closes the return fluid path through the flow-restrictor 17 to the tank 9 and therefore the entire output of the pump 8 will pass through the electro-valve 14 and will be supplied to the cylinders 5 and 5'. The latter then cause rapid levelling of the body of the machine. When the inclination of the body 1 is again smaller than 10.degree., the laterally inner float switch (23, or 23') is reopened and the second electro-valve 18 therefore again opens, reducing the rate of levelling.

When the inclination of the machine body to the horizontal has reached the maximum limit of safety, the axle 3 operates one of the limit switches 34 and 34', so that the relay 27 is energized, causing operation of the interruptor 28 and therefore of the optical and acoustic alarm device 30 and the flasher lamp 29. As the same time the current is cut off from the relays 22, 23, 22', 23' of the float switches and so the two electro-valves 14 and 18 remain in their rest positions and the hydraulic circuit is inoperative. Automatic levelling control therefore ceases.

The first electro-valve 14 can also be controlled manually by means of the emergency lever 32, which acts mechanically on the moving part of the valve 14 and which also operates the micro-switch 31 so as to interrupt the current which would normally be supplied to the relays 22, and 22' by the inner float switches 20 and 20' supplying this current directly to the electro-valve 18, which causes the entire output flow from the pump 8 to reach the first electro-valve 14, allowing rapid levelling of the body 1 of the machine, as previously described, as if one of the inner float switches 23, 24' has been operated.

It will be appreciated that details of practical embodiments of this invention may depart widely from the illustrated embodiment without departing from the scope of this invention.

Claims

I claim:

1. Device for effecting automatic levelling of the body of a threshing-harvesting machine, comprising in combination:

a. two liquid-containing vessels mounted on opposite lateral sides of the body;

b. conduit means intercommunicating said vessels;

c. first and second magnetic level-sensitive switches in each respective vessel, said two switches being located at different lateral positions in each vessel and being operable selectively in response to lateral inclinations of said body of the machine to the horizontal by more than a first and a second angle respectively, the second angle being greater than the first;

d. a double acting first electro-valve operable by the first switches;

e. an hydraulic circuit including two hydraulic levelling actuators, said first electro-valve being included in said circuit and controlling supply of hydraulic fluid thereto;

f. a pump in said hydraulic circuit;

g. a second electro-valve operable by the second switches, said second electro-valve normally reducing the flow of hydraulic fluid under pressure from said pump to the actuators, the latter being supplied with the full pump flow to effect rapid levelling when said second electro-valve is operated by said second switches;

h. means operating said two electro-valves manually;

i. means sensitive to excessive inclination of said body to the horizontal to prevent said two electro-valves from operating, and,

j. an alarm device operable by said means sensitive to excessive inclination.

2. Device according to claim 1, wherein said manual control means for operating the two electro-valves comprise a lever arranged to act mechanically on the movable part of the first electro-valve and including an electric switch operable simultaneously by said lever to operate said second electro-valve so that the entire output flow of said pump is supplied to said levelling actuators for rapid levelling.

3. Device according to claim 1, wherein said means to prevent said two electro-valves from operating and for activating said alarm device are formed by two limit switches arranged to be operated mechanically by an axle of the machine when the body of the machine exceeds a maximum predetermined inclination to the horizontal, a relay connected to said limit switches, an interruptor connected to said relay and operable upon energization thereof, and an optical and acoustic alarm device connected to the interruptor for operation thereby in response to operation of either limit switch, said limit switches upon operation also breaking the electric circuits of said two electro-valves.