Patent Application
20150096279
This invention relates to harvesting heads for agricultural harvesters. In particular, it relates to reels for harvesting heads. More particularly, it relates to crop-engaging fingers mounted on bats of the reels.
Harvesting heads for agricultural harvesters typically have reels that engage the top parts of the crop plants and sweep them backwards on to the harvesting head itself. This ensures that the crop plants, when the roots are severed by reciprocating knife at the base of the plant, fall onto the harvesting head itself, instead of falling on the ground and being wasted.
The reels are typically constructed as several long bats that have fingers that extend downward from the bat and engage the tops of the crop plants. The bats are typically formed as elongate aluminum alloy tubes between 2 and 4 cm in diameter. The fingers include an upper end that is clamped to the outer surface of the tube and a lower end in the form of an elongate finger that is formed integral with the upper end. As the bat rotates, it rotates all of the fingers causing the lower ends of the fingers to gently engage the upper portion of the crop and to pull it backwards.
The fingers are prevented from rotating around the bat by alignment structures that mechanically engage the finger in the bat such that the finger cannot rotate about the bat without the alignment structures being sheared. The alignment structure is typically a plastic or metal pin or protrusion, a screw or a bolt.
In one arrangement, the finger is injection molded out of plastic. In this case, the alignment structure is typically a plastic protrusion, stud, or surface irregularity that is injection molded integral with the finger and of the same material and that mechanically engages the bat.
When these plastic alignment structures are placed under load, they tend to wear against the aluminum alloy of the bat, and eventually the plastic alignment structure either shears off or is worn away. When this happens, the fingers are free to rotate about the bat and no longer engage the tops of the crop plants properly.
What is needed therefore is a finger with stronger alignment members that are less subject to wear or shearing. It is an object of this invention to provide such a finger.
In accordance with a first aspect of the invention, a finger configured to be mounted on a bat of a reel of an agricultural harvesting head is provided, the bat defining a mating aperture configured to receive a portion of the finger, the finger comprising: an elongate lower finger portion configured to engage upper portions of crop plants; an upper clamp portion integrally formed with the elongate lower finger portion, wherein the upper clamp portion defines a central region configured to receive the bat, the upper clamp portion further comprising, a strap comprising a polymer that is configured to wrap around the bat and to be attached to the bat, and an alignment pin disposed on an inner surface of the strap and extending into the central region wherein the alignment pin is configured to be received within a mating aperture in the bat, and wherein an outer surface of the alignment pin comprises a material having greater wear resistance and/or greater tensile strength than the upper clamp portion.
The finger may be solid, may be comprised of ferrous alloy, may be comprised of plastic, may be comprised of reinforced plastic, and may be comprised of brass or bronze
The upper clamp portion may define an aperture that is configured to receive and support an end of the alignment pin.
The elongate lower finger portion and the upper clamp portion may be formed as a single injection molded plastic part, and the alignment pin may be pressed into an aperture in the upper clamp portion.
The elongate lower finger portion and the upper clamp portion are formed as a single injection molded plastic part, in which they are molded around the alignment pin.
The finger may further comprise a threaded fastener that extends through a first aperture in a free end of the strap and is threadedly received in a second aperture formed in a receiver of the upper clamp portion.
The threaded fastener may not extend into the bat.
The alignment pin may be generally circular in cross-section, and the mating aperture may be generally circular in cross-section.
A coating, layer, or skin may be provided on an outer surface of the alignment pin that is disposed between the alignment pin and the mating aperture.
In accordance with another aspect of the invention, a method of molding a finger configured to be mounted on a bat of a reel of an agricultural harvesting head is provided, the bat defining a mating aperture configured to receive a portion of the finger, wherein the method of molding a finger comprises the steps of: molding as a unitary body an upper clamp portion configured to fix the finger to the bat and an elongate finger portion configured to engage upper portions of crop plants; and simultaneously molding an aperture in the upper clamp portion that is configured to support an alignment pin, wherein the alignment pin is configured to be received in the mating aperture.
The step of simultaneously molding an aperture may further comprise the step of mold-forming the aperture about the alignment pin.
The method may further comprise a step of simultaneously molding a coating, layer, or skin over an outer surface of the alignment pin.
Referring to the Figures herein, a reel finger 100 comprises an elongate lower finger portion 102 and an upper clamp portion 104. The lower finger portion 102 and the upper clamp portion 104 are integrally formed, preferably as a single injection molded polymeric part.
The reel finger 100 may be formed of nylon, polypropylene, high molecular weight polyethylene, and ultra-high molecular weight polyethylene. The reel finger may be reinforced, such as by glass fibers, carbon fibers, glass beads or other like materials used to strengthen or improve the wear resistance of thermoplastics.
The upper clamp portion 104 comprises a strap 106 and a collar 108. The collar 108 is disposed at a distal end of the strap 106 and defines an aperture 110 configured to receive a threaded fastener 112 such as a bolt or screw. The upper clamp portion 104 also comprises a receiver 114 which is provided with an aperture 115 to receive and threadedly engage the threaded shank of the threaded fastener 112.
To mount the reel finger 100 on a bat 116 (
The strap 106 is then flexed back to its original shape (substantially as shown in all of Figures herein) in which the generally circular central region 120 is circular, and the threaded fastener 112 is inserted into the aperture 110 in the collar 108. The free end of the threaded fastener 112 is inserted until it engages the aperture 115, at which time the threaded fastener 112 is threaded into the aperture 115 which encloses the bat 116 and clamps the upper clamp portion 104 on to the bat 116. The threaded fastener 112 in the illustrated arrangement does not extend into the bat 116. Instead, it pulls the two free ends of the strap 106 together, thereby increasing the tension in the strap 106 and therefore the pressure of the strap 106 against the bat 116. The threaded fastener 112 does not extend into the bat 116 and therefore does not function to align the reel finger 100 with respect to the bat 116.
The friction between the inner surface of the strap 106 and the outer surface of the bat 116 may not be sufficient to keep the reel finger 100 from rotating on the bat 116 when the lower finger portion 102 engages the tops of crop plants during harvesting.
For this reason, the upper clamp portion 104 further comprises an alignment pin 122 that extends inwardly from an inner surface of the strap 106 into the generally circular central region 120 and generally toward the center of the generally circular central region 120. The bat 116 (
The alignment pin 122 further comprises a ring 126 that is disposed about a central portion 127 of the alignment pin 122 to provide a more wear resistant and stronger outer surface for the alignment pin 122.
The central portion 127 of the alignment pin is preferably molded out of the same material (and in the same process) as the elongate lower finger portion 102 and the upper clamp portion 104. It is the outer surface of the ring 126 that abuts the interior surface of the mating aperture 124.
The ring 126 comprises a more wear resistant and stronger material than the material that forms the upper clamp portion 104 and that forms the central portion 127. This material may be a plastic or a metal.
In one arrangement the ring 126 comprises a ferrous alloy. In another arrangement it comprises a brass alloy. In another arrangement the ring 126 is comprised of a bronze alloy. In another arrangement, the ring 126 comprises a reinforced plastic. In another arrangement, the ring 126 comprises a glass or fiber filled plastic. The ring 126 may have an integrally formed cover portion 128 disposed at its upper end such that it forms a cap. The ring 126 may have a flange 130 disposed at its lower end to provide greater strength and easier assembly. The ring 126 may be right circular cylinder in cross-section.
In one arrangement, the ring 126 may be inserted into a mold cavity, the mold cavity closed, and the plastic that forms the reel finger 100 can be then be injected into the mold cavity to form the finger integrally with the ring 126. In another arrangement, the reel finger 100 can be molded and the ring 126 later pressed onto the (now solid) alignment pin 122.
The upper clamp portion 104 is provided with a recess 132 that extend circumferentially around the base of the alignment pin 122 and is configured to receive the lower end of the ring 126.
Referring now to
In one method of forming the arrangement of
In another method of forming the arrangement of
The alignment pin 122 in the arrangement of
In
Both the arrangement of
Finally, it may be beneficial to provide a coating, layer or skin that is sealed against the outer surface of alignment pin 122 (and/or the ring 126) to protect the alignment pin 122 (and/or the ring 126) from the elements and thereby help to prevent corrosion of the alignment pin 122 (and/or the ring 126). Such a coating, layer or skin, depending upon its thickness, could also provide a relatively tight fit between the alignment pin 122 (and/or the ring 126) and the aperture 124 of the bat 116 that would reduce relative movement between the alignment pin 122 and/or the ring 126, and aperture, and thus to reduce chafing.
