CA2238247A1 - Segmented meter roller with symmetrical components - Google Patents

Abstract

There is provided a new and useful segmented meter roller assembly for metered product delivery between a meter box and a series of product runs leading to a series of product distributors or distribution headers, the assembly comprising: a shaft for mounting for rotation in the box; and a series of roller sections mounted on the shaft, the roller sections chosen from the group consisting of blank sections or molded segmented metering sections; and wherein the series of roller sections includes at least one of the molded segmented metering sections, each of the molded segmented metering sections secured to the shaft for rotation therewith and comprising at least one fluted segment and at least one blank segment.

Description

TITLE OF THE INVENTION
SEGMENTED METER ROLLER WITH SYMMETRICAL COMPONENTS
FIELD OF THE INVENTION
This application relates to segmented meter roller assemblies and to molded segmented metering sections for use in such assemblies.
BACKGROUND OF THE INVENTION
In modern large scale agricultural operations, seed and/or fertilizer are typically applied to the soil through a series of seed tubes which are associated with soil working tools across the width of a soil working machine. Typically a group of such tubes is fed seed or fertilizer by a distribution header. The distribution header is in turn fed from a tank which may be configured as a separate cart for towing in advance of or trailing the soil working implement.
A metering system is associated with the tank for distribution of product from the tank to the distribution headers of the seed tubes.
The present invention is concerned with a metering system comprising a segmented meter roller situated below the tank in a meter box assembly secured to the tank. Typically the meter box will have a series of outlets known as runs, each of which leads through intermediate tubing to one of the distribution headers.
The total number of possible runs typically extends the length of the segmented meter roller. Depending on the number of distribution headers on the soil working implement, the segmented roller assembly will consist of fluted metering sections corresponding to runs which are operational and preferably a single blank roller spacer extending across the width of the runs which are not operational.
Product is then delivered to distribution headers which are connected to the runs containing the fluted metering sections and no product is delivered from those runs which are, in effect, blanked off. Along with the metering sections and blank sections, the segmented meter roller assembly may comprise various spacers, bearings, etc.
Various problems have arisen in the use of meter rollers. Typical such problems involve corrosion caused by leakage of product through gaps between segments; pulsing delivery of product to the headers; difficulties in delivering a large seed or large particle product to the headers at the proper rate; and difficulties in delivering very fine products to the headers at the desirable rate.
Against this background the present invention addresses problems in each of the enumerated areas and others.
PRIOR ART
Various approaches have been used in the past to attempt to provide segmented meter rollers.
One such prior method varies the amount of product delivered by each fluted metering roller by fixing a varying number of thin rings about the center line of the roller to simply reduce the volume of product to be delivered by the roller.
This was intended to compensate for the differing numbers of seed or fertilizer delivery tubes emanating from the distribution header fed by that particular metering roller.
Another method used to reduce flow from a given run comprises reducing the width of the fluted metering section and inserting separate spacers on each side of the metering section. This method results in a very large number of parts in the segmented meter roll assembly with consequent severe tolerance and torque problems.
SUMMARY OF THE INVENTION
It has now been discovered that all of the problem areas to which reference was made in the background discussion above can be alleviated to a significant extent by the use of molded segmented metering sections which are formed as a single unit per run which may have any desired combination of blank and fluted surfaces.
Thus, the invention provides a segmented meter roller assembly for metered product delivery between a meter box and a series of product runs leading to a series of product distributors or distribution headers, the assembly comprising:
a shaft for mounting for rotation in the box; and a series of roller sections mounted on the shaft, the roller sections chosen from the group consisting of blank sections or molded segmented metering sections; and wherein the series of roller sections includes at least one of the molded segmented metering sections, each of the molded segmented metering sections secured to the shaft for rotation therewith and comprising at least one fluted segment and at least one blank segment.
In a further embodiment the invention provides a molded metering section for use in a segmented meter roller assembly, the segmented metering section comprising at least one fluted segment and at least one blank segment.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate embodiments of the invention:
FIGURE 1 illustrates an air cart of which the present invention may form a component;
FIGURE 2 is a cross-section through a part of the cart of Figure 1 illustrating the general layout in the meter box;
FIGURE 3 is an exploded view of segmented metering sections and a meter roller assembly according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figures 1 and 2 illustrate the context of the present invention. Air cart 40 is of known configuration and comprises tank 42, or optionally a number of tanks (not illustrated), which may be mounted on frame 44, which is in turn carried on wheels 46. A metering assembly 48 is mounted on the bottom 50 of tank 42.
A blower 52 forces air past the outlet area 54 of metering assembly 48 to carry product 55 from metering assembly 48 to appropriate tubing to distribution headers on a soil working implement (headers and implement not shown). A series of dividers 56 at the meter assembly outlet 54 define a series of runs which direct product into a corresponding series of delivery tubes 58.
In addition to dividers 56, meter assembly 48 includes meter box 60 within which are disposed agitators 62 and meter roller assembly 64.
All of the foregoing is known in the prior art.
With reference to the segmented meter roller assembly illustrated in Figure 3, a shaft 1 1, preferably of hexagonal configuration, is journalled for rotation in the metering box 60 of an air cart 40. A sprocket 1 is secured at one end of shaft 11 to indicate shaft rotation speed. The shaft is preferably driven by a hydraulic motor, and certain implications of this drive mode will be discussed later.
The segmented roller assembly shown in the drawings is intended for an air cart 40 having several runs, 2 of which include a segmented metering section 12. As will be understood by those skilled in the art, such assemblies may include additional runs, typically, for example, 8 runs. Any of those runs may contain a metering section or a blank section, depending on the number of distribution headers which are provided on the soil working implement in association with which the air cart is used.

A central blank section having an outer spacer 19 is illustrated to blank out unused runs. It is highly preferred that all unused runs be grouped centrally, so that a single blank section can be used across all unused runs.
The central blanked section comprises an outer spacer 19 and an inner spacer 20, the latter fixed by pin 7 to shaft 1 1 for centrally locating the spacer 20 on shaft 1 1.
The bearing seats 14 abut against inner spacer 20 and include a hexagonal bore, so that they rotate with spacer 11. Bearing seats 14 abut a machined shoulder within outer spacer 19. When bearings 5 are seated on seats 14, the outer races of the bearings are in frictional engagement with outer spacer 19, thus allowing inner spacer 20 to rotate, while outer spacer 19 is held against rotation. Outer spacer 19 is held against rotation by virtue of the cap screw abutting against a part of the top of meter box 60.
The bearing shield 13 is then forced against the surface of bearing seat 14 sealingly engaging the O-ring 6 between the two. Bearing shield 13 is also in sealing engagement with the end of the central spacer assembly.
It should be noted that the central spacer assembly illustrated in Figure 3 may be a special purpose arrangement which may serve functions unrelated to the metering per se as, for example, in pressure equalization.
The two metering roller sections 12 abut against the bearing shields 13.

_7_ Outer bearing seats 4 carry similar bearings 5 separated from the outer ends of metering rollers 12 by a second set of bearing shields 13. The outer bearing seats 4 are pinned by associated pins 7 to maintain the position of the segments between them. The outer bearings 5 journal shaft 1 1. It is important to note that there would be no more bearings in the case of say, a 6 run assembly.
In that case the intermediate sections or blank section would simply abut one another. In the absence of a central spacer assembly where all runs are in use, the shaft would carry only the two outer end bearings.
In this respect it is important to note that it is highly preferable that all of the sections be somewhat compressed together for sealing purposes. It is outer seats 4 and their associated pins which maintain the compression across the roller assembly. The covers 3 are applied at the end of the metering section of the roll. A hub 2 is preferably fixed on the end of shaft 1 1 and incorporates a speed sensor.
At the other end of the assembly there is preferably positioned an identification disk 23 to identify the metering roller type as, for example, between extra fine, fine, and coarse. A cam arrangement 24 and 25 is fixed to the end of shaft 1 1 by pin 26 and forms the driver for agitator 62 (Figure 2) to ensure smooth flow from the product tank into the meter box.
The segmented metering sections 12 comprise a fluted segment 30 and two smooth blank segments 32. The combined width of the fluted section and the two blank sections is essentially the same as the width of a single run.

_g_ While the positioning and the proportions of the segments may vary as desired, it is preferable that the metering sections comprise, as illustrated, a central fluted segment and two blank segments which are symmetric about the mid point of the roller.
Clearly, a run may have a preselected width, as in the case of existing machines, and the overall width of the metering section and of the fluted and blank segments of that roller can be varied to adapt an existing machine to the invention.
The arrangement described offers significant advantages over prior art such assemblies.
In a conventional assembly, wherein the metering roller is fluted across its entire width; that is, across the width of the run, the shaft will often be required to be operated at relatively low rpm, as, for example, typically down to about 2 rpm, in order to deliver correct amounts of product. At this lower rpm, there is a significant time during each rotation when no product is moved from the metering box into a run. This is because there is no flow when the end of a flute passes the run inlet. There is an interruption of flow as every flute passes. This has been found to result in a pulsing effect in the delivery of product to the distribution header and, consequently, in the uneven application of seed or fertilizer. By increasing the speed of rotation, the blank time during which a given flute is passing is reduced and the result is that a much more even flow of product to the distribution headers and hence into the soil can be achieved.
Clearly the increase in rpms means that a larger quantity of product would be delivered to the distribution header by any given metering roller.
The present arrangement avoids that problem by decreasing the capacity of the fluted section of the metering roller. Thus, the shaft can be operated at higher rpm while delivering the same amount of product to the distribution header as would have been delivered under an older full width fluted metering section.
The arrangement offers the additional advantage that product can be readily handled which could not have been handled at low rpm. For example, for large size low volume seed, such as corn, the metering roller in the prior art could not be operated at a sufficiently low rpm to efficiently deliver proper amounts of product. At the higher rpm these types of product can readily be handled.
A further very significant advantage of the arrangement is that the hydraulic motors which are the preferable drive means for the assembly are very inefficient at low rpm. An increase of rpms from 2 to 4 or 6 rpm is highly significant in this regard. At those higher rpms, the variable rate hydraulic drive will operate very efficiently. Furthermore, the equipment cost for the variable hydraulic motor to operate only at the higher rpms is significantly decreased.
Apart from the above operational advantages, there are significant improvements in cost and life expectancy of the present assembly over prior art assemblies. Since it is highly preferable that the present metering section be molded as a single urethane piece, there is a clear cost saving over prior art such assemblies where multiple components were used. As well, because there are significantly fewer components on the shaft, there is much less of a tolerance problem as between any two components. For example, in some prior art such assemblies, because there are a large number of components, the components must be manufactured somewhat shorter than ideal tolerance, in order to ensure that all components will be able to be fitted on the shaft. The result is a somewhat sloppy and loose arrangement. This results in product working down through the gaps between components and resulting in corrosion problems.
In the present case the components are substantially all urethane and are assembled on the shaft under overall compression, so that there are no gaps or much less chance of gaps developing. Hence corrosion problems are minimized.
In certain prior art such assemblies, where spacers are employed for various reasons, it is common to simply use a plastic spacer with a circular bore which will fit over the shaft in a loose arrangement, such that the spacer does not rotate with the shaft. This frequently results in the bore in the spacer becoming eccentric and this can contribute to the opening of gaps in the assembly, thus leading to the corrosion problem noted above. In the present case some of the spacers are integral with the metering rollers and others are blanks with hexagonal bores which are fitted on the shaft for rotation with the shaft. In the present case for other purposes a central spacer may be provided, as described above, the outer shell of which is held against rotation but the inner shell of which rotates with the shaft, the two shells being separated by bearings.
Further, the use of multiple components which are in contact with, but not rotating with, the shafts results in severe torque problems.

In a typical air cart, there might be eight runs emanating from the meter box and thus up to eight metering sections. Typically a run is about 3 inches wide, so that the assembly would then be about 24 inches long. Typically a variety of metering sections are interchangeable on the shaft, the flutes of which are of varying degrees of fineness.
In the preferred case the tank is pressurized to essentially equalize pressure on both sides of the metering assembly. The pressurization may be at about 40 inches of water or 1 '/Z psi.
The product is pneumatically driven through the runs and ultimately to the soil, and such air seeders are well known in the art.
The metering roller section in the present case may have fluted sections up to about 1 inch of the 3 inch overall width.

Claims (2)

1. A segmented meter roller assembly for metering product delivery between a meter box and a series of product runs leading to a series of product distributors, said assembly comprising:
a shaft for mounting for rotation in said box;
a series of roller sections mounted on said shaft, extending across said runs, said roller section chosen from the group consisting of blank sections or molded metering sections;
and wherein said series of roller sections includes at least one of said molded metering sections, each said metering section corresponding to one said run, secured to said shaft for rotation therewith and comprising at least one fluted segment and at least one blank segment.

2. A molded metering section for use in a segmented meter roller assembly, said metering section comprising at least one fluted segment and at least one blank segment.