The present invention relates generally to agricultural implement frames and, more specifically to tube joints for such frames.
Many agricultural implement frames include tubular members welded or connected together by brackets. The joints are subjected to very high loads and stresses.
Tube over tube connections for an implement frame construction typically employ one of two methods of construction. The first method includes welding the top and bottom tubes directly together using flare bevel welds. The direct weld procedure requires joint welds in hard to reach positions. If welds are required around tube corners, robotic welding techniques often are not used since programming the robot to closely follow the corners is not always possible. Fatigue and less than optimum load transfer characteristics of some joints can result in a weakened frame. The second method of frame construction uses gusset plates vertically extending between the top and bottom tubes and welded to the tubes. The weld positioning is better using the gusset method than the direct tube to tube weld method, but gusset weld methods often result in a joint with a lower fatigue life compared to other types of joints.
A further method involves tube through tube construction such as shown and described in commonly assigned U.S. Pat. No. 6,016,877. Such construction provides excellent frame tube joints and a very strong overall frame without need for extensive fixturing during manufacture, but such joints require laser cut apertures through tubes and are relatively expensive to produce. In addition, welding tube ends to adjoining tubes in the same plane continues to be a source of difficulty.
It is therefore an object of the invention to provide an improved frame joint for an agricultural implement frame. It is another object to provide such a joint that overcomes most or all of the aforementioned problems.
It is a further object of the invention to provide an improved welded frame joint for an implement which is stronger, subject to less fatigue, and easier to manufacture than at least most previously available implement frame joints. It is another object to provide such a joint which is self-fixturing and is easily weldable using standard fillet welds at conveniently accessed locations.
Tube over tube implement frame joints include self-fixturing weldable castings positioned between upper and lower tubes. Standard fillet welds connect the tubes to the casting at conveniently accessible locations. The material in the casting is selected to optimize load transfer between the top and bottom tubes to improve the fatigue life of the joint. The weldable casting can be placed at any required joint area and provides an easy weld joint for both human and robotic welders. Since the casting is self fixturing, the top tubes can be located by simply placing in the casting without need for costly fixtures. In another embodiment of the invention, castings are provided at the ends of tubes to facilitate butt joint fixturing and welding for connecting tubes lying in the same plane. The above-described connections spread the weld locations for increased resistance to parallelogramming and better load balancing at the joints. The connections also provide added strength and fatigue resistance at tube joints adjacent hinge locations.
These and other objects, features and advantages of the present invention will become apparent from the description below taken in view of the drawings.
Referring to
To provide self-fixturing and a strong, permanent connection between the upper and lower beams, a weldable connector or casting 30 is positioned at joint locations. The casting 30 as shown in
As best seen in
Planar channel walls 52 extend upwardly from the bottom 32b to define the channel portion 32c. The walls 52 include uppermost edges 56 having a height approximately half the dimension of the corresponding wall of the beam 16. A notch 58 is centrally located in each uppermost edge and provides a paint drainage channel. The connector 30 is fixed to the upper beam 16 by welds at locations 60 between the corners of the beam. The welds 60 are offset from the corners for easy access, to reduce or eliminate the welds at the beam corners, and to provide better load and stress distribution at the joints. The leg portions 40 are welded to the corresponding walls of the beam 20 at locations 62 also offset from the beam corners.
In an alternate embodiment (
To provide butt joints for a planar configuration (
Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
The entire right, title and interest in and to this application and all subject matter disclosed and/or claimed therein, including any and all divisions, continuations, reissues, etc., thereof are, effective as of the date of execution of this application, assigned, transferred, sold and set over by the applicant(s) named herein to Deere & Company, a Delaware corporation having offices at Moline, Ill. 61265, U.S.A., together with all rights to file, and to claim priorities in connection with, corresponding patent applications in any and all foreign countries in the name of Deere & Company or otherwise.