Disc cutterbar quick-change knife with retaining pin assembly

A quick connect apparatus for connecting a knife to a rotary disc cutterhead comprising a spring-loaded connector and a locking device which, when installed, prevents unintentional release of the knife from the cutterhead. The quick connector with locking device replaces a conventional bolted connection and reduces the time necessary to remove and reinstall a knife on a rotary cutterhead compared to a bolted knife connector while improving knife retention compared to known quick-change knife connection mechanisms.

BACKGROUND OF THE INVENTION

This invention relates generally to machines for severing standing crops from the ground using a plurality of rotatable discs having knives mounted thereon to sever standing crop by an impact action upon rotation of the discs and, more particularly, to an improved mechanism for connecting disc cutter knives to a machine that allows the knives to be easily removed from the rotatable discs and replaced.

Rotary disc cutterbars are well known in the agricultural arts and used in the harvest of a variety of standing crops. A typical disc cutterbar comprises a plurality of cutterheads spaced along the length of the cutterbar. The cutterheads each typically comprise a rotating cutting disc including diametrically opposed cutting blades (though configurations with three or more blades are known) driven by a drivetrain housed within the cutterbar that receives motive power from the prime mover to which the disc mower is attached. For background information on the structure and operation of some typical disc cutterbars, reference is made to U.S. Pat. No. 5,996,323, issued to Campbell, the descriptive portions thereof being incorporated herein in full by reference.

Cutterbars frequently impact rocks and other obstructions in a field which can damage the knives. Further, knives also become dulled by their interaction with the crop and require periodic removal for sharpening or replacement. Knife retention is traditionally accomplished through the use of threaded fasteners which require multiple components and involve time-consuming processes to remove and replace damaged or worn knives. Quick-change knife attachment systems are known wherein the knife is retained by a pin that is held in position by a spring which reduce the part count for the knife connection mechanism. Operating history of spring-actuated quick-change knife attachment systems has shown that knives may be inadvertently released from the rotating cutting discs during operation, especially when the knives strike obstacles such as stones, limbs, or the ground. Significant risk of injury and damage may result from inadvertantly released knives as the cutterheads spin at up to 3,000 rpm.

It would be advantageous to provide a locking mechanism for a quick-change knife attachment system that would prevent inadvertent knife release while continuing to offer a convenient manner to quickly remove and replace a cutterhead knife. Additional advantages would be realized by a locking mechanism that adds no loose parts to the cutterhead to reduce the chance that sub components might be misplaced during knife changes or become projectiles if dislodged from the cutterhead.

SUMMARY OF THE INVENTION

Accordingly, the present invention, in any of the embodiments described herein, may provide one or more of the following advantages:

It is an object of the present invention to provide a knife connector for use on a rotary disc cutterhead allows the knife to be easily removed and reinstalled and includes a secondary locking mechanism to prevent inadvertent knife release.

It is a further object of the present invention to provide a quick-change knife connector for use on a rotary disc cutterhead which relies primarily on a spring element to retain the knife in position and include a locking pin to prevent unintentional release of the spring element.

It is a further object of the present invention to provide a quick-change knife connector for use on a rotary disc cutterhead having a locking pin that prevents release of the knife and in which the locking pin is non-separable from the cutterhead.

It is a still further object of the present invention to provide a locking pin for a quick-change knife connector on a rotary disc cutterhead that allows installation and removal of knives using existing tools for the task.

It is a still further object of the present invention to provide a retaining pin for a quick-change knife connection apparatus for a rotary disc cutterhead that is durable in construction, inexpensive of manufacture, carefree of maintenance, easily assembled, and simple and effective to use.

These and other objects are achieved in accordance with the instant invention by providing a quick connect apparatus for connecting a knife to a rotary disc cutterhead comprising a spring-loaded connector and a locking device which, when installed, prevents unintentional release of the knife from the cutterhead. The quick connector with locking device replaces a conventional bolted connection and reduces the time necessary to remove and reinstall a knife on a rotary cutterhead compared to a bolted knife connector while improving knife retention compared to known quick-change knife connection mechanisms.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Likewise, “forward” and “rearward” are determined by the normal direction of travel. “Upward” and “downward” orientations are relative to the ground or operating surface as are any references to “horizontal” or “vertical” planes. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures.

Referring now to the drawings and particularly toFIG. 1, a crop harvesting header10having a rotary disc cutterbar12of the type on which the present invention finds utility is presented. Disc cutterbars have been utilized in agricultural harvesting implements for many years. A disc cutterbar comprises a plurality of transversely spaced rotary disc cutter modules14each being driven for rotation about a generally vertical axis. For background information on the structure and operation of disc cutterbars, reference is made to U.S. Pat. No. 4,815,262, issued to Koch et al. and to U.S. Pat. No. 5,996,323, issued to Campbell et al., the descriptive portions thereof being incorporated herein in full by reference. Each disc cutter module14has two or three knives16mounted adjacent to the outer periphery of a rotating disc element15which are held in place by a knife connection mechanism.

Now referring toFIGS. 2 through 7collectively, a first embodiment of the knife connection mechanism30comprises a knife mounting boss19formed on the rotating disc element adjacent to the peripheral edge17of the rotating disc element15and a spring plate42. Mounting boss19and spring plate42are connected to the disc element15for rotation therewith and arranged to form a small gap between the mounting boss19and the spring plate42. One knife connection mechanism30is provided for each knife16that is connected to the rotating disc element15, typically two knives that are equally spaced apart around the disc element15periphery.

A pivot bushing52is connected to the spring plate42and extends therefrom toward the mounting boss19. A mounting hole11provided in each knife16is configured to receive the pivot bushing52when the knife16is installed for cutterhead operation and position the knife16between the spring plate42and the mounting boss19along a knife pivot axis100. The pivot bushing52at least partially extends into an aperture20in the mounting boss19when the spring plate is in its normal operating (unflexed) position (shown inFIGS. 2 and 3) so that the knife is restrained on the pivot bushing52between the spring plate42and the mounting boss19. The pivot bushing52connection with the spring plate42and the aperture20in the mounting boss19transfers knife loads to the structure of the rotating disc element.

In order to prevent inadvertent disengagement of the knife16from the pivot bushing52, a retainer pin54is provided. In a first embodiment, retainer pin54comprises a head59, an elongate shank58, and at least one catch structure55extending generally perpendicularly from the elongate axis of the retainer pin54. The number and orientation of catch structures55is symmetrically configured about the elongate axis of the retainer pin54. In the preferred embodiment, the catch structure is formed from a separate pin member55ainserted through a cross-shank bore57in the shank58adjacent to the end51so that portions of the pin member55aextend beyond the diameter of the shank58. The pin member55ais sized for a slight interference fit into cross-shank bore57so that it remains in position once installed into the cross-shank bore57. Pin member55ais preferably a roll pin.

The head59allows the retention pin54to be conveniently rotated and to provide a stop to prevent the pin from passing through the aperture20in a first direction. A washer69may also be used to provide a larger contact surface for the head59and/or to reduce the opening diameter of aperture20to a diameter closer to that of the shank58. The washer69is preferably non-removably attached to the mounting boss19, such as by welding or an equivalent mechanical connection. By sizing the opening18in the washer69to a diameter less than the protrusion of the pin member55aand non-removably connecting the mounting washer69to the mounting boss19, the retainer pin54cannot be separated from the connection mechanism30once the pin member55ais installed thereby reducing the likelihood that the retaining pin54will be misplaced during knife changes.

A retainer engaging structure60is fitted within an end of the pivot bushing52connected to the spring plate42. The retainer engaging structure60is configured with one or more release grooves65and one or more detents66, the number of each matching the number of catch structures55present on the retainer pin54. The release groove65allows the catch structure55to pass axially through the retainer bushing54and be fully disengaged from the bushing54while the detents66limit the degree of axial movement and prevent the catch structure from being removed axially from the bushing. In the preferred embodiment, the detents66and release grooves65are oriented such that rotation of the retainer pin54approximately one-quarter of a turn will shift the alignment of the catch structure between the detent and the release groove.

A spring washer61is provided between the head59and the mounting boss19(or washer69) to allow limited axial movement of the retainer pin54and to bias the pin54so that the catch structures55remain in the detents66when the pin54is so oriented. When the catch structures55are engaged in the detents66, the retainer pin54prevents the space between the spring plate42and the mounting boss19from being increased, thereby preventing the knife16from being disengaged. The retainer pin54thus provides an additional degree of protection from an accidental knife release, such as could occur if the spring plate was sufficiently deflected during a knife impact with an obstacle.

The catch structure55may be also be integrally formed from the shank58(e.g., machined from a single material billet) in lieu of a separate pin member55a. Alteration of the spring washer61and the mounting washer69are required to allow each to be fitted on the shank58over the protruding catch structure55.

A skilled artisan will note that the orientation of the knife connection mechanism30may be vertically inverted so that the retainer pin54is accessed from below. The disadvantage to an inverted orientation is the risk of damage to the head59of the retainer pin54as it will be positioned adjacent to the ground and subject to impact with obstacles on the ground. Similarly, the pivot bushing52may be permanently connected to the mounting boss and engaged by an aperture in the spring plate and continuing to orient the retainer pin54with the head59adjacent to the mounting boss19. This configuration requires connecting the retainer engaging structure60to the spring plate while the remainder of the pivot bushing is connected to the mounting boss, complicating the design and increasing production cost.

Finally referring toFIGS. 8 and 9, the knife connection mechanism30is shown first inFIG. 8with the retainer pin54positioned for release and a release tool90positioned as it would be at the beginning of the process to release a knife16. The retainer pin54is positioned to align the retention tabs55with the release grooves65to permit the retainer pin54to move axially within the pivot bushing. The release tool90is this used to flex the spring plate42to increase the separation with the mounting boss to a position at which the free end of the pivot bushing52is sufficiently spaced apart from the mounting boss19to allow the knife16to be disengaged from the bushing52and removed from the connection mechanism30. The retainer pin54may also be withdrawn to the extent practical (retainer tabs55in contact with the underside of mounting washer69) to reduce the degree of flexure of the spring plate42required to release the knife16. Installation of a knife is accomplished in the reverse manner, requiring that the spring plate42be deflected to open a space between the pivot bushing52and the mounting boss19through which the knife may pass. Once the knife mounting hole11is engaged on the pivot bushing52, the spring plate42is allowed to return to its static position which engages the free end of the pivot bushing52with the aperture20. Retainer pin54is then inserted into the pivot bushing52to the maximum extent and turned in a manner to reposition the retention tabs55into the detents66. With the retainer pin54installed and engaged with the detents, the spring plate42is prevented from being flexed to disengage the pivot bushing52end from the aperture20thereby reducing the chance that a knife16may be inadvertently released from the connection mechanism30.