Abstract:
A manually operated mechanism for locking the first table of a bale wagon in the raised position. The mechanism uses gravity to both engage and disengage the lock to permit an operator to safely service the components of the wagon below the first table.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to agricultural bale wagons for retrieving bales from a field, and more particularly to a mechanical locking mechanism for holding the first table in a raised position. 
   The general operation of a bale wagon is clearly described in U.S. Pat. No. 2,848,127. Specifically, the bale wagon to which the instant invention applies functions to automatically pick up and stack bales, such as hay bales, from the positions in which they are dropped by hay cutting and baling machines which precede the bale wagon in the field. 
   Bale wagons operate by moving along a line of bales lying in a field, and aligning the chute-like mechanism on the front of the machine, the bale loader, with each bale. A vertical chain conveyor with protruding cleats lifts the bale upwardly and a deflector then tips the bale sideways, onto the receiving bed of the wagon, called the first table, at a point which is essentially the foremost portion of one of the side edges of the wagon. 
   At this point, a cross-conveyor moves the bale across the width of the wagon, forming a one-bale wide row on the first table at the leading edge of the wagon. The first table then tips rearwardly, depositing the row of bales on the front edge of the second table. This process is repeated until the second table is filled with its full compliment of bales. This table is then tipped rearwardly placing the bales onto a larger bed, called the third table, where tiers accumulate. When a predetermined number of tiers have been accumulated on the third table, this bed, in turn, is tipped rearwardly to deposit a multilayered stack of bales. Typical bale wagons are also capable of automatically unloading an entire stack, for some bale wagons as many as 160 bales. 
     FIGS. 3 and 4  provide detailed views of the locking mechanism for the first table  20  as it would appear on the left side of the bale wagon. While the left side is the most convenient for the operator, and the most logical location, it could be located on either side. Left side pivot arm  50  (right side pivot arm  30  not shown) is pivotably affixed to support member  12  by a pivot pin (not shown) on transverse axis  52 . Another pivot pin  53  ( FIG. 3 ) on transverse axis  54  pivotally supports a stop tab assembly comprised of stop tab hub  56  with a stop tab  58  affixed thereto, as by welding. Stop tab hub  56  is free to rotate about the pivot pin on axis  54 , and bushings and/or bearings provide ease of rotation. Also pivotally supported on the pivot pin  53  on the transverse axis  54  is a handle assembly comprised of a handle hub  60 , handle  62  and tang  64 . Handle  62  and tang  64  are affixed to handle hub  60 , as by welding. Tang  64  is of such length and location as to extend into the rotational path of stop tab  58 . 
   It would be a distinct advantage to provide means for conveniently and safely locking and unlocking the first table in the raised position. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an important object of the present invention is to provide a manually operated mechanism for locking and unlocking the first table in the raised position. 
   Another object of the present invention is to provide a mechanical mechanism for selectively locking the first table of a bale wagon in the raised position. 
   It is another object of the instant invention to provide a mechanism for permitting an operator to safely service the operating components of the first table of a bale wagon. 
   It is a further object of the instant invention to provide a safety mechanism that allows no movement of the first table until the operator has safely returned to the cab and depresses the first table up switch. 
   It is a still further object of the instant invention to provide a first table lock that contains no springs, and uses gravity for both engagement and disengagement. 
   It is an even still further object of the instant invention to provide a mechanism for locking the first table of a bale wagon in the raised position that uses low profile components that do not collect chaff and other debris. 
   It is another object of this invention to provide a safety mechanism for the first table of a bale wagon that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple, versatile and effective in use. 
   These and other objects are attained by providing a manually operated mechanism for locking the first table of a bale wagon in the raised position. The mechanism uses gravity to both engage and disengage the lock to permit an operator to safely service the components of the wagon below the first table. 

   
     DESCRIPTION OF THE DRAWINGS 
     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
       FIG. 1  is a partial right front perspective view of a first table of a bale wagon suitable for use of the present invention; 
       FIG. 2  is a partial cross section of the table of  FIG. 1 , taken along lines  2 — 2 ; 
       FIG. 3  is a partial rear elevation view of the left end of the first table of  FIG. 1 , showing some of the components of the locking mechanism of the instant invention; 
       FIG. 4  is a partial front perspective view of the left end of the first table pivot, showing the components of the instant invention in the table locked up position; 
       FIG. 5  is an end view of the mechanism of  FIG. 4 , taken along lines  5 — 5  with the first table in the lowered position; and 
       FIG. 6  is a, similar to  FIG. 5 , showing the locking mechanism in the unlocked position and the first table generally in the raised position. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   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. 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 by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. 
   The general operation, and the concept of a first table, is fully disclosed and discussed in the BACKGROUND OF THE INVENTION, and since the locking mechanism to be described relates to the first table, this disclosure will begin with reference to the first table partially shown in  FIG. 1 . First table  10  is partially comprised of a pair of spaced-apart supports  12 ,  14  rigidly affixed to and supported by the main frame (not shown) of the bale wagon. The bale-supporting portion of the first table is relatively simple, comprised generally of two transverse pipe-like rails  16 ,  18  generally held together by a longitudinal relatively flat framing structure  20  to which rails  16 ,  18  are attached. Structure  20  merges rearwardly into an inclined structure  22 . The framing structure  20  and inclined structure  22  are relatively rigid and sturdy in construction so as to maintain its integrity throughout a long life of rugged use. A top cap member  23  interconnects the two supports  12 ,  14 , providing significant structural integrity. Surface  22  is inclined and continuous primarily to deflect straw, chaff and debris and direct it toward the ground and support and guide bales from the first table to the second table as the first table pivots, as discussed below. 
   Referring now to  FIG. 2 , primary structural components of the pivoting mechanism of the first table are shown to comprise a generally vertical pivot arm  30  affixed to structure  20  and generally perpendicular thereto. Pivot arm  30  is pivotably affixed to support  12  via bolt or pin  32 . To make the pivoting motion easier and more stable, bushings and spacers may be used. The first table employs two axially aligned pivot pins, spaced, in the preferred embodiment, on either side of structure  20 . A single lever arm  34  is located generally centrally of the table and affixed to structure  20 . A single-acting hydraulic cylinder  36  is pivotably affixed at end  38  to a structural portion of the bale wagon frame (not shown) and cylinder ram  40  is pivotably affixed to lever arm  34 . Thus, when ram  40  of hydraulic cylinder  36  is extended, table  10  pivots upwardly about pin  32 . The attachment point  42  of ram  40  to lever arm  34  must be below pivot pin  32  in order for the table to pivot as required. 
   The first table of a typical bale wagon is quite heavy and usually powered by a single-acting hydraulic cylinder, thus relying on the weight of the table to return to its resting horizontal position. Additionally, the operation of a bale wagon generates a significant volume of chaff and other debris that accumulate in the area of the first stable. Since it is necessary to perform daily servicing under the first table, and since neither the hydraulic nor electrical circuits provide a means to hold the table in the vertical or up position without the operator holding down the momentary first table up switch (the release of which will cause the table to fall), it is inconvenient for a single person to perform full maintenance in this area of the bale wagon. 
   A cam  70 , with outer cam surface  72  is affixed to pivot arm  50  and located such that the outer end of stop tab  58  will, under conditions to be explained below, follow cam surface  72  as the first table is pivoted to the up position. Cam surface  72  includes a somewhat step-shaped notch  74  in the upper end thereof that will lock onto stop tab  58  under conditions to be described below in regard to the operation of the locking mechanism. Handle  62  is held in the unlock position by a spring clip or clasp  76  that is affixed to cap member  23 . 
   When the operator or mechanic wants to either clean under the first table or wants to service components under the first table, the locking mechanism can be easily engaged to safely lock the first table in the raised position. To lock the table from the table down position shown in  FIG. 3 , with the handle  62  held in place by spring clip  76 . The operator pulls handle  76  a short distance clockwise, releasing it from clip  76 . The weight of handle  62  rotates handle hub  64  clockwise causing tang  64  to engage stop tab  58 , biasing it into contact with cam surface  72  of cam  70 . The operator then returns to the control panel of the bale wagon and raises the first table. Pivot arm  50  pivots clockwise about axis  52  and stop tab  58  stays in contact with cam surface  72  until it is pushed into notch  74 . The operator then lowers the table via the control panel. Lowering of the table puts the weight of the table on the stop tab, locking the table in the up position. 
   To disengage the locking mechanism, the operator moves handle  62  counterclockwise to engage spring clip  76 , as shown in  FIG. 6 , and then via the control panel raises the table to the full up position. Even though the table is already in the up position, activation of the hydraulic cylinder  36  will further rotate the table about axis  52  a small distance. This small distance will release stop tab  58  from notch, whereby the weight of stop tab  58  rotates stop hub  56  counterclockwise, thus allowing free use of the first table and bale wagon. 
   It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.