Method for calculating characteristic geometrical or control variables of a three point hitch

Patent metadata

Field	Value
Publication number	US-10098272-B2
Application number	US-201715788932-A
Country	US
Kind code	B2
Filing date	Oct 20, 2017
Priority date	Oct 20, 2016
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A method is provided for calculating characteristic geometrical or control variables of a three-point hitch for an agricultural tractor in which the hitch includes a lifting strut having a mounting position which is adjustable by means of a lifting arm in one of a plurality of receiving holes formed in a lower link and the hitch is pivotable by the lifting strut. The method includes moving the lower link initially into a horizontal angle position α=0 and capturing the corresponding angular position Px, Pz of the lifting arm and a corresponding angular position γ of the lifting strut relative to the vertical. The method further includes determining which of the receiving holes satisfies a geometrical constraint condition and determining the mounting position of the lifting strut on the lower link.

First claim

The invention claimed is:

1. A method for calculating characteristic geometrical or control variables of a three-point hitch for an agricultural tractor, comprising:
providing the hitch with a lifting strut having a mounting position which is adjustable by means of a lifting arm in one of a plurality of receiving holes formed in a lower link, the hitch being pivotable by the lifting strut;
moving the lower link initially into a horizontal angle position α=0;
capturing a corresponding angular position P x , P z of the lifting arm and a corresponding angular position γ of the lifting strut relative to a vertical;
determining which of the receiving holes satisfies a geometrical constraint condition based on

(

U
ix

U
iz

)

=

(

P
x

P
z

)

-

a
⁢

⁢

(

sin
⁢

⁢
γ

cos
⁢

⁢
γ

)

in which U ix , U iz designate the position coordinates of the i-th receiving hole and a designates a variable representing the length of the lifting strut; and
determining the mounting position of the lifting strut on the lower link.

2. The method of claim 1 , further comprising:
forming the lifting strut to be length-adjustable;
determining an instantaneous length l h of the lifting strut as a second geometrical or control variable;
proceeding from the determined mounting position of the lifting strut on the lower link for which purpose the position coordinates U jx , U jz of the receiving hole determined as being occupied are inserted into the geometrical constraint condition in order to then solve the geometrical constraint condition for the variable a with a=l h .

3. The method of claim 1 , further comprising:
determining an attachment position of a length-adjustable upper link in one of a plurality of receiving holes of a tractor-side mounting point as a third geometrical or adjustment variable,
moving the upper link initially into one of two upper link end positions; and
determining the angular position a of the lower link and an angular position β of the upper link relative to the horizontal in order to determine a mast height m i , proceeding from a length l o ={circumflex over (l)} o of the upper link in an end position, a length l u of the lower link and a position U x , U z of a tractor-side articulation point of the lower link for each of the possible attachment positions of the upper link on the tractor-side mounting point, the mast height representing a distance between an upper link coupling point and a lower link coupling point for attaching an agricultural auxiliary or attached implement based on

m
i

=

(

M
ix

-

U
kx

)

2

+

(

M
iz

-

U
kz

)

2

,

⁢

with
⁢

(

M
ix

M
iz

)

=

(

O
ix

O
iz

)

+

1
^

o

⁢

(

-
cos

⁢

⁢
β

sin
⁢

⁢
β

)

,

⁢

(

U
kx

U
kz

)

=

(

U
x

Assignees

• Deere & Co

Inventors

• Kremmer Martin
• Gresch Valentin

Classifications

• B60D1/48

  characterised by the mounting · CPC title

• A01B63/1117 Primary

  using a hitch position sensor · CPC title

• B60D1/01

  Traction couplings or hitches characterised by their type · CPC title

• B60D1/141

  Arrangements or frames adapted to allow the connection of trailers to tractor three-point hitches · CPC title

• A01B59/067 Primary

  the lower arms being lifted or lowered by power actuator means internally incorporated in the tractor · CPC title