Mechanism for the automatic steering of agricultural machines, especially combines

Claim 2

In an agricultural harvesting machine adapted to be propelled over the ground capable of contacting standing crops, and with means to steer said machine, said machine having an automatic steering mechanism comprising a crop edge sensor operatively interconnected to an element that moves over a range of positions relative to the movement of the crop sensor, said sensor being operative to sense and to continuously engage the crop edge, a first electrical transducer coupled to the movable element of the crop sensor, a second electrical transducer coupled to an element of the steering means, said element being operatively interconnected to said steering means so as to allow the element to move through a range of positions in respect to the movement of the steering means, both of said electrical transducers being arranged so as to have an electric output signal which represents the position of the respective movable element to which they are interconnected, an electric means for comparing both output signals with each other and to energize an electric motor which is coupled to the steering means so as to control said steering means by attempting to balance the output signals of the electric transducers during operation of the machine.

Claim 3

An agricultural machine as set forth in claim 1 wherein said electric means comprises an electronic circuit for comparing the respective electric signals of the transducers and amplifying the excess unbalanced portion of the electric signals compared in said circuit, an electronic reversing switching means which receives said output signal and which, responsive to said amplified output signal closes the feed lines of the electric motor so as to energize the motor in one particular direction in an attempt to offset the resulting output signal and thereby balance the potential difference created in the electric circuit by said electric transducers.

Claim 4

An agricultural harvesting machine as set forth in claim 2 wherein said first and second electrical transducers consist of potentiometers for comparing and measuring the potential difference that is created upon movement of the respective movable elements associated with the crop edge sensor and the steering means.

Claim 5

An agricultural harvesting machine as set forth in claim 3 wherein said respective potentiometers are connected to a direct current source, said potentiometers also having sliding contacts which are connected to the movable elements of both the crop edge sensor and the steering means so that said contacts move in relation to the movement of the crop edge sensor and the steering means to create a particular potential difference in the respective potentiometers.

Claim 6

In an agricultural machine as set forth in claim 2 wherein said electronic reversing switching means comprises a plurality of solenoids connected to the end of the amplification portion of the electronic circuit, and relays operatively connected to said solenoids and the electric motor for closing the respective feed line of said motor thereby controling the excitation of the motor so that the motor will operate in such a manner as to offset the resulting output signal and thereby attempt to balance the potential differences as measured by said potentiometers.

Claim 7

An agricultural harvesting machine as set forth in claim 2 wherein said electronic circuit comprises at least two lead-in circuits for comparing the resulting potential differences as measured by the respective potentiometers, and which fuRther porvides the difference in potential to be transmitted to the output circuit as an output signal, and at least two output circuits which act as unidirectional amplifier circuits which amplify said output signal prior to its entering the electronic reversing switching means.

Claim 8

An agricultural harvesting machine as set forth in claim 6 wherein said lead-in circuits comprises a plurality of diodes placed between the respective potentiometers and their base electrodes, emission electrodes inversely connected to said potentiometers, a plurality of transistors connected to said base electrodes and which have collectors running from said transistors to the output circuit.

Claim 9

An agricultural harvesting machine as set forth in claim 6 wherein said output circuits comprises a plurality of transistors connected in series to each other and which are connected to the collector of the lead-in circuit to collect the output signal emitted from the lead-in circuit and amplifying said signal in steps as it passes through the series connected transistors so that upon reaching the last transistor of said circuit the signal will activate the solenoids and the relays connected with the electronic reversing switching means to excite the electric motor.

Claim 10

An agricultural harvesting machine as set forth in claim 6 wherein the output circuits comprise tripping means interconnected to said output circuits for interrupting operation of the output circuit when header is raised, header drive is disengaged, threshing mechanism is disengaged, the harvesting machine is driven backwards, or when steering wheels reach their maximum deviation.

Claim 11

An agricultural harvesting machine as set forth in claim 1 wherein said steering means comprises a steering structure operatively interconnected with said steering means for either manually or automatically controling said steering means so that movement of the steering structure will impart a resulting movement to the steering means thereby allowing the operator to control the direction of travel of the machine either manually or automatically.

Claim 12

An agricultural harvesting machine as set forth in claim 10 wherein said steering mechanism comprises a rotatable shaft mounted in a steering column positioned and fixed to the floor of the operator''s platform of the harvesting machine, a steering wheel mounted on the upper end of said rotatable shaft to enable the operator to manually rotate the shaft, an upper bushing rigidly fixed to said rotatable shaft and positioned within said steering column said bushing further containing a plurality of pins which can be raised or lowered by the activation of a displacing lever, the outer end of said lever extending through and projecting from the steering column while the inner end of the lever is pivotally connected to a support mounted within said steering column said support also containing arms which have one end interconnected to said lever while the other end is connected to said pins so that the movement of the lever will pivot its end support mounted in the steering column thereby moving the arms which are interconnected both to said lever at the support and to the pins of the upper bushing said movement of the lever ultimately either raising or lowering the pins contained in the upper bushing depending on the motion imparted initially to said lever, a lower freely rotatable bushing placed on said shaft below said upper bushing the lower bushing being restrained from axial movement by rings placed above and below said lower bushing, said lower bushing also comprising an upper collar said collar provided with a plurality of bores capable of receiving the pins associated with the upper bushing, the lower bushing being interconnected with the electric motor by a connecting means so that during operation of the motor the lower bushing can freely rotate about said steering shaft without imparting any rotation to the steering shaft so that the operator can manually rotate said shaft without interference but iF the operator wishes to engage the automatic steering mechanism he needs simply move the displacing lever which protrudes from the steering column to engage the plurality of pins positioned in the upper bushing which is fixed to said steering shaft and thereby lower said pins into the rotatable lower bushing bores so that movement of the lower bushing generated and controlled by the electric motor of the automatic steering mechanism through the connecting means can be imparted to the rotatable steering shaft through said rigidly mounted upper bushing.

Claim 13

An agricultural harvesting machine as set forth in claim 11 wherein said connecting means comprises a reduction gearbox having one end connected to said electric motor, said gearbox containing a worm and a worm wheel connected to a rotatable sprocket, a rotatable rigidly fixed on the freely rotatable lower bushing, said sprockets being interconnected by an endless chain mounted on said sprockets.