Patent Application
20090056298
The present invention relates to retracting finger auger assemblies utilized in grain harvesting headers and the like and, more particularly, to a retracting finger auger assembly having means for preventing the fingers thereof from retracting too far into the auger tube and causing damage or catastrophic failure.
Retracting finger auger assemblies are well known in the art and have been used for many years to converge crop materials centrally and then feed them rearwardly. Typically, the auger assembly is set up such that the fingers extend as they engage crop material at the front of the auger and retract as they release material at the back.
A typical retracting finger auger assembly has a stationary crank shaft within the auger tube and fingers that are pivotally mounted on an eccentrically offset finger shaft portion of the crank shaft. The auger tube rotates while the crank shaft remains stationary, but because the fingers project outwardly through holes in the auger tube, they are driven around the finger shaft by the auger tube as it rotates. Because the auger tube rotates about one axis while the fingers pivot about the axis of the offset finger shaft, the fingers extend and retract through the holes in the auger tube as they revolve about the finger shaft.
In some conditions, particularly if the finger shaft is long and unsupported in the middle, the finger shaft can bounce around within the auger tube and flex to such an extent that one or more of the fingers may become over-retracted into the interior of the auger tube. When that happens, significant damage and catastrophic failures can result.
Accordingly, the present invention is intended to eliminate this over-retraction problem. In a preferred embodiment, each long run of a finger shaft within an auger tube is provided with a flex limiter that is disposed to block excessive flexing of the finger shaft. Anti-friction surfaces associated with the flex limiter are secured to the auger tube for movement therewith relative to the finger shaft but are disposed to be engaged by the finger shaft when necessary to prevent untoward flexing.
The present invention is susceptible of embodiment in many different forms. While the drawings illustrate and the specification describes certain preferred embodiments of the invention, it is to be understood that such disclosure is by way of example only. There is no intent to limit the principles of the present invention to the particular disclosed embodiments.
In
In the illustrated embodiment, auger assembly 10 extends substantially the entire width of header 12 and includes a long auger tube 18 having a cylindrical sidewall 20. Oppositely inclined auger flighting 22 and 24 on opposite left and right halves of the tube 20 are disposed to converge cut crop centrally of header 12 for subsequent discharge rearwardly therefrom into a feeder house 26 or the like (
Auger tube 18 is supported at its opposite ends for driven rotation about the longitudinal axis of tube 18. In this respect, the left end of auger tube 18 as illustrated in
At the opposite, right end of auger tube 18 as illustrated in
Auger assembly 10 further includes a retracting finger mechanism 50 that broadly includes two primary components, i.e., a set of retracting fingers 52 and a stationary crank shaft 54 that carries fingers 52. In the illustrated embodiment, fingers 52 are located generally along the full length of auger tube 18, although it is to be appreciated that the principles of the present invention are not limited to this arrangement. For example, it is possible that fingers 52 might be provided only in the central region of auger tube 18, leaving the two flighted portions thereof essentially finger-free. In any event, in the illustrated embodiment, crank shaft 54 is full length of auger tube 18 and is divided into three sections, comprising a right section, a central section and a left section.
Each such section of crank shaft 54 includes a laterally offset shaft portion comprising a finger shaft 56 that extends parallel to the axis of rotation of auger tube 18 in eccentric relationship therewith. Opposite ends of each offset finger shaft 56 are provided with cranks 58 and 60 that are in turn fixed to portions of crank shaft 54 that are coaxial with the axis of rotation of auger tube 18.
Starting with the left end of left finger shaft 56a as illustrated in
Each of the fingers 52 is pivotally mounted on its finger shaft 56 for rotation about the axis of finger shaft 56. As illustrated perhaps best in
The outer end of each finger tube 80 projects through and is slidably received by a guide 86 fixedly secured within a mounting hole in the sidewall 20 of auger tube 18. In the left and right portions of auger tube 18, finger guides 86 are disposed at diametrically opposed and axially spaced positions along auger tube 18, while in the central portion of auger tube 18, finger guides 86 are preferably arranged in side-by-side groups of two or three at suitable intervals about tube 18.
As a result of this construction, when auger tube 18 is rotated by drive sheave 36 in a counterclockwise direction viewing
It will be appreciated that, particularly in the left and right sections of the auger tube 18, finger shafts 56 are quite lengthy compared to the diameter of such shafts. Therefore, there is a tendency for finger shafts 56 to bounce and flex during rotation of auger assembly 10. Such action is particularly likely to occur when some of the fingers 52 encounter unanticipated loads. For example, when fingers 52 are fully extended on the front side of auger tube 18, the outboard portions of fingers 52 have significant mechanical advantage over the inboard portions thereof. Thus, a load experienced by the exterior portion of the finger can cause the finger to fulcrum about the finger guide 86 and flex the finger shaft 56 in a way that may seek to retract fingers 52 on the opposite side of auger 18 more than their intended amount. If one of the fingers 52 becomes retracted so far that it is pulled back inside auger tube 18, it can punch a hole in the auger tube as it attempts to extend during the extension phase of the finger, or cause catastrophic failure of the mechanism.
In accordance with the present invention, each of the left and right finger shafts 56a and 56b is provided with at least one flex limiter 88 between the supporting bulkheads for the finger shaft. Each flex limiter 88 includes a transverse, annular, metallic member 90 having a circular periphery 92 that is welded or otherwise permanently affixed to the interior surface of sidewall 20 approximately mid-length of the finger shaft 56a or 56c. Annular member 90 extends at right angles to the longitudinal axis of auger tube 18 and has a centrally located, enlarged circular opening 94 through which the finger shaft 56a or 56c passes. Opening 94 is concentrically disposed with respect to the axis of rotation of auger tube 18. A front face 96 of member 90 slopes gradually in the axial direction as opening 94 is approached.
Flex limiter 88 further includes an anti-friction guide ring 98 disposed concentrically within annular member 90 and securely fastened thereto. In one preferred form of the invention, guide ring 98 is constructed from ultra high molecular weight (UHMW) polyethylene, although other materials may also be utilized. Guide ring 98 circumscribes the corresponding finger shaft 56a, 56b and has a radially inner surface 100 that is normally slightly spaced radially outwardly from the outer extremity of finger shaft 56 so that surface 100 does not normally contact finger shaft 56 during rotation of auger tube 18. However, in the event of slight outward flexing of finger shaft 56, surface 100 comes into engagement with shaft 56 and prevents further flexing thereof, thereby also preventing further retraction of those fingers 52 that are already fully retracted to the extent illustrated in
Guide ring 98 also has a circumferential, radially outwardly extending lip 102 integral with surface 100 and overlying a portion of the front face 96 of transverse member 90. Lip 102 serves as the means by which guide ring 98 is secured to annular member 90, having a plurality of suitable fasteners 104 that project through lip 102 and into retaining engagement with member 90. In one preferred form of the invention, fasteners 104 may take the form of machines screws. Preferably, guide ring 98 is formed from two semi-circular halves, as shown particularly in
It will be noted that each flex limiter 88 does not interfere with rotation of auger tube 18 or extension and retraction of fingers 52. In normal operating conditions, limiters 88 do not make engagement with their finger shafts 56a, 56c. However, in the event that any of the fingers 52 experiences unusual loading such as would normally cause a shaft 56a or 56c to flex, the corresponding limiter 88 is well positioned to engage the slightly flexed shaft before it can move to such an extent that damage or catastrophic failure can occur.
The inventor(s) hereby state(s) his/their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his/their invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.
