Machine and method for acquiring data for measuring the twist and concavity of agricultural discs

Abstract

The machine includes a rotational mounting bracket, upon which an agricultural disc is supported and held. A hold-down plate that can rotate freely is arranged above the mounting bracket. A linear actuator displaces the hold-down plate vertically in a downwards direction to press the agricultural disc. A laser measurement device is coupled to a linear guide where the hold-down plate forms part of a rotational head-piece fixed to a rod of the linear actuator. A method includes determining a central reference height on a model disc, determining the height of points in the periphery of the disc to be measured, calculating the average of the measured heights and comparing with the central reference height to determine whether the disc is valid or not.

Claims

1. A method for acquiring data for measuring twist and concavity of agricultural discs, characterized in that it comprises the following stages: a) placing a model disc in a center of a mounting bracket; b) positioning a laser measurement device in a central area of the model disc above the same; c) making the model disc rotate; d) obtaining reference data corresponding to points of the model disc located equidistant from a center of the model disc using a start point located in the laser measurement device; e) determining a central reference height that corresponds to the distance, perpendicular to the disc, from said center of the model disc to the start point; f) demounting the model disc; g) mounting an agricultural disc to be measured centrally on the mounting bracket, ensuring it is immobilized by means of lowering a hold-down plate; h) displacing the laser measurement device in order to position it such that it corresponds with a periphery of the agricultural disc; i) measuring the height of various independent points, and various pairs of diametrically opposed points, exclusively taken along the periphery of the agricultural disc; j) calculating a difference between the maximum and minimum heights, obtaining the twist of the agricultural disc; k) calculating an average of the heights of each pair of diametrically opposed peripheral points; l) comparing the average of each pair of diametrically opposed peripheral points to the central reference height of the model disc, obtaining a concavity in said diameter; m) calculating an average of different concavities measured, obtaining a concavity of the disc.

2. The method for acquiring data for measuring twist and concavity of agricultural discs according to claim 1, characterized in that it comprises the following steps: n) rotating the agricultural disc for a section of a second turn; o) lifting the hold-down plate; p) demounting the agricultural disc; and q) repeating steps g) to j) with at least one additional agricultural disc.

3. The method for acquiring data for measuring twist and concavity of agricultural discs according to claim 1, characterized in that it comprises the following steps: comparing the twist obtained with pre-established tolerance levels, in order to determine whether or not the agricultural disc is valid in terms of a twist variable.

4. The method for acquiring data for measuring twist and concavity of agricultural discs according to claim 1, characterized in that it comprises the following steps: comparing the concavity of the disc obtained with pre-established tolerance levels, in order to determine whether or not the agricultural disc is valid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1.—Is a perspective view of the machine for acquiring data for measuring the twist and concavity of agricultural discs.

(2) FIG. 2.—Is a cross-section of a rotational head and hold-down plate assembly.

(3) FIG. 3.—Is a cross-section of an actuator device, with a built-in vertical shaft, the upper end of which is fixed to the mounting bracket, the assembly formed by the vertical shaft and the mounting bracket being rotated by means of a motor.

(4) FIG. 4.—Is a plan view of a model disc, initially used to identify a central reference point.

(5) FIG. 5.—Is a plan view of an agricultural disc with various reference points around the perimeter.

(6) FIGS. 6 and 7.—Are schematic views providing a basic representation of the system for measuring twist and concavity, by taking data at the periphery of the agricultural disc, in addition to a central reference point that corresponds to the center of the agricultural disc.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT OF THE INVENTION

(7) The machine for acquiring data for measuring the twist and concavity of agricultural discs comprises the following elements, listed according to the numbering adopted in the drawings: 1.—Frame 2.—Vertical cylinder 3.—Hold-down plate 3a.—First annular end 4.—Linear guide 5.—Laser measurement device 6.—Table platform 6a.—Hole 7.—Actuator device 8.—Motor 9.—Rear protection surface 10.—Side protection surface 11.—Side protection surface 12.—Legs 13.—Mounting bracket 13a.—Second annular end 14.—Rod 15.—Female sleeve 15a.—End annular recess 16.—Intermediate ball bearing 17.—Upper fixation sleeve 17a.—Circumferential portion 18.—Lower fixation sleeve 18a. Circumferential portion 19.—Screws 20.—Appendix 20a.—Blind grooves 21.—Rotational head-piece 22.—Set screws 23.—Vertical shaft 23a.—Annular extension 24.—Casing 25.—Ball bearings 26.—Housing 27.—Male element 28.—Agricultural disc 28a.—Central perforation 29.—Model disc 29a.—Central perforation

(8) In principle, it comprises a frame 1, a rear protection surface 9 and two side protection surfaces 10-11, which define a frontally open surrounding space.

(9) A vertical cylinder 2 is installed in the upper area on the frame 1, which may be pneumatic or hydraulic and is responsible for driving a hold-down plate 3 that forms part of a rotational head-piece 21 connected to the rod 14 of the vertical cylinder 2 by a female sleeve 15, which threads onto the rod 14. Likewise, a linear guide 4 is fixed onto the frame 1, upon which a laser measurement device 5 is displaced.

(10) Furthermore, the machine has a table platform 6 supported by means of legs 12, the legs 12 in turn being supported on the machine frame 1 itself.

(11) An actuator device 7 is mounted to the lower portion of this frame 1, a mounting bracket 13 protruding from the actuator device 7 through a hole 6a made in the table platform 6.

(12) The female sleeve 15 has an end annular recess 15a, in which an intermediate axial load ball bearing 16 is inserted, the same being held using two fixation sleeves, namely an upper 17 fixation sleeve and a lower 18 fixation sleeve, both being joined with screws 19.

(13) The intermediate ball bearing 16 is housed in a hollow delimited by the end annular recess 15a in the female sleeve and by circumferential portions 17a and 18a of both fixation sleeves, namely the upper 17 and lower 18 fixation sleeves, respectively.

(14) The lower fixation sleeve 18 has an appendix 20 to which the hold-down plate 3 is coupled with screws 22, the ends of which fit into a number of blind grooves 20a in the appendix 20 of the lower fixation sleeve 18.

(15) The rotational head-piece 21 in turn comprises the two fixation sleeves, i.e. the upper 17 and lower 18 fixation sleeves, alongside the hold-down plate 3.

(16) In turn, the actuator device 7 is formed by a casing 24, which is fixed to the frame 1. Inside the casing 24, there is a vertical shaft 23, supported by ball bearings 25. In correspondence with the lower end of the vertical shaft 23, a motor 8 is coupled, which provides the vertical shaft 23 and as such, the mounting bracket 13, with rotational movement.

(17) In contrast, the upper end of the vertical shaft 23 is inserted into the mounting bracket 13, which has a housing 26 at its center, in order for a male element 27 to be inserted therein, where a central perforation 28a of the agricultural disc 28 to be measured is adjusted, a perforation 29a of a model disc 29 initially placed on the mounting bracket 13 also being adjusted.

(18) It must also be noted that the mounting bracket 13 is supported against an annular extension 23a of the vertical shaft 23.

(19) Having sufficiently described the structure of the machine, object of the invention, we shall now go on to describe how the machine works.

(20) The agricultural disc to be measured is inserted into the male element 23, whilst it is supported against the mounting bracket 13. The vertical cylinder 2 is subsequently driven, the hold-down plate 3 therefore being lowered until an annular stop 3a of the hold-down plate 3 comes into contact with the agricultural disc 28, fixing it against the mounting bracket 13.

(21) The motor 8 drives the rotation of the vertical shaft 23, also making the mounting bracket 13 rotate jointly and, the hold on the agricultural disc 28 provided by the hold-down plate 3 onto the mounting bracket means that activating the motor 8 also causes the rotational head-piece 21 assembly including the hold-down plate 3 to be pulled.

(22) The laser measurement device 5 takes data measurements as the agricultural disc 28 rotates.

(23) The data taken by the laser measurement device 5 is stored in a PLC, in order to subsequently calculate the twist and concavity of the agricultural disc 28 using a computer program, thereby checking whether or not the agricultural disc 28 complies with the required specifications previously set down.

(24) Should the disc fall within the required tolerance limits, the machine will emit a green light, whilst if it does not, the same will emit a red light.

(25) The method for acquiring data for measuring the twist and concavity of agricultural discs is as follows:

(26) Firstly, at the start of the day, a central reference height is measured using the model disc 29, in accordance with a central point “X” on the model disc 29.

(27) In order to do so, the laser measurement device 5 is positioned along the linear guide 4, such that it corresponds with the central area of the model disc 29 fitted onto the male element 27 by means of its central perforation 29a, the hold-down plate being kept in an upper position.

(28) In the position, the model disc 29 is made to rotate and reference data corresponding to four points a-b-c-d at an equal distance from the center of the model disc 29 are taken, in order to determine the central reference height. The points are measured relative to a start point “Z” in the machine, located such that it corresponds with the laser measurement device 5, the heights between each one of the points relative to the start point “Z” being taken into account, the average value of the heights corresponding to the reference data subsequently being calculated, in order to thus obtain the central reference height of the model disc 29.

(29) The reference data is acquired as follows: a first piece of data “a” is taken before beginning to rotate the model disc 29. The model disc 29 is then set into rotational motion. A second piece of data “b” is taken at 0.9 seconds. A third piece of data “c” is taken at 1.8 seconds. A fourth piece of data “d” is taken at 2.7 seconds.

(30) Once the central reference height has been calculated, the model disc 29 is dismounted and each agricultural disc 28 to be measured is mounted, a number of pieces of measurement data being taken for the different agricultural discs 28 to be measured, in order to calculate the twist and concavity, this measurement data corresponding to the heights measured from the start point “Z” of the laser measurement device 5 and each one of the points along the periphery of the corresponding agricultural disc 28.

(31) In order to calculate concavity and twist, the laser measurement device 5 is displaced along the linear guide 4 to the periphery of the agricultural disc 28 to be measured, where it will collect data corresponding to the periphery (points along the perimeter) of the agricultural disc 28 at very short time intervals of at least 0.001 seconds.

(32) From the data acquired in previous steps, six pieces of measurement data corresponding to specific points (A, B, C, D, E and F) are used to calculate concavity, which correspond to three diametrical axes of the agricultural disc 28: A-D, B-E and C-F.

(33) When the agricultural disc begins to rotate, 0.8 seconds pass without collecting or taking data. Subsequently, the data used to calculate concavity is collected as follows, as the agricultural disc 28 is in rotational movement: Data “A” is collected at 0.8 seconds after the agricultural disc 28 begins to rotate. Data “B” is collected at 1.465 seconds. Data “C” is collected at 2.13 seconds. Data “D” is collected at 2.795 seconds. Data “E” is collected at 3.46 seconds. Data “F” is collected at 3.325 seconds.

(34) Once the laser measurement device 5 has collected the last piece of data, the agricultural disc 28 continues to rotate for a further 1.465 seconds, until the hold-down plate 3 is lifted.

(35) All of the data is collected by rotating the agricultural disc 28 by one full turn, plus a portion of a second turn on the mounting bracket 13.

(36) The laser measurement device 5 collects data as follows: a laser diode emits a beam, which crosses an emitter lens and crashes against the upper surface of the agricultural disc 28. The beam reflected from the agricultural disc 28 is subsequently collected by a reflective lens and sent to a sensor, which detects the intensity peak, thereby establishing the distance from the agricultural disc 28.

(37) The twist of the agricultural disc 28 is calculated in accordance with the data collected and corresponds to the difference in height (the direction perpendicular to the plane of the agricultural disc 28) between the maximum and minimum values of all the measurement data acquired along the periphery of the agricultural disc.

(38) In contrast, the concavity of the agricultural disc 28, in accordance with the data collected, is calculated as follows:

(39) First of all, in one embodiment of the invention, the concavity of three diametrical axes of the agricultural disc 28 are calculated:

(40) $\mathrm{Concavity}\mathrm{of}a\mathrm{first}\mathrm{axis}\text{:}$$\left(\mathrm{AD}\right)=\frac{\mathrm{distance}\left(\mathrm{ZA}\right)+\mathrm{distance}\left(\mathrm{ZD}\right)}{2}-\mathrm{distance}\left(\mathrm{ZX}\right)$$\mathrm{Concavity}\mathrm{of}a\mathrm{second}\mathrm{axis}\text{:}$$\left(\mathrm{BE}\right)=\frac{\mathrm{distance}\left(\mathrm{ZB}\right)+\mathrm{distance}\left(\mathrm{ZE}\right)}{2}-\mathrm{distance}\left(\mathrm{ZX}\right)$$\mathrm{Concavity}\mathrm{of}a\mathrm{third}\mathrm{axis}\text{:}$$\left(\mathrm{CF}\right)=\frac{\mathrm{distance}\left(\mathrm{ZC}\right)+\mathrm{distance}\left(\mathrm{ZF}\right)}{2}-\mathrm{distance}\left(\mathrm{ZX}\right)$
where “X” refers to the central reference point of the model disc 29, whilst “Z” refers to a start point at coordinates of the machine located such that they correspond with the laser measurement device 5, the distance (ZX) constituting the central reference height.

(41) The concavities of the three axes is then measured, thereby obtaining the concavity of the agricultural disc.

(42) The values, corresponding to both concavity and twist, are compared with their respective tolerance values, thereby deciding whether or not the piece is acceptable.

(43) As such, the machine and measurement method object of the invention reduce testing time (the time it takes the disc to complete one full turn) and increase precision, given that the testing does not rely on human ability.

(44) Furthermore, using the data acquired, it is possible to check whether or not the manufacturing process employed to make the agricultural discs complies with the desired technical specifications.

(45) As such, using the corresponding formula, it is possible to obtain short-term capacity indices, which indicate how suitable the manufacturing process is.