Abstract:
A latch to secure folding implements in a transport configuration. The latch is constructed so as to permit selective disengaging of the latch to allow the folding implement to be configured for operation. A latching mechanism with a pivoting portion engages a crossbar in latching. One of the latching mechanism or pivoting portion is suspended on an extension bar which is cantilevered and suspended from either a main frame or a folding arm. The latching system tolerates misalignment of the main frame and folding arms through the suspension system.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to folding implements such as those used in field work in agricultural, for instance, wheel rakes. More particularly, the present invention relates to an improved locking system to secure the implement in a folded position for transport. 
     2. Background Art 
     Many implements today require folding to narrow their width for transport through gates and on public roadways. An example of such a folding implement is disclosed in U.S. Pat. No. 7,313,905 by Vaske et al., which is hereby incorporated in its entirety by reference. 
     Present-day transport locks require an operator to exit the towing vehicle to manually engage the locks before transport. Frequently, operators fail to utilize manual locks prior to transport as it requires the operator to get out of or off the towing implement to install. Operators may fail to recognize the value of the transport lock over their time and effort, especially during busy seasons. 
     Some present-day towed implements include automatic transport lock mechanisms to lock the implement in the folded position. Due to strains induced to the implement by its resting on uneven ground, the present-day transport locks may fail to align. Hence, these existing automatic locks require the implement to be on level ground in order to properly align the folding arms and main frame for folding. In addition, the automatic locks fix the folded arms of the implement more or less rigidly to the main frame of the implement, thus inducing stresses in the implement as it is transported over uneven terrain. Such stresses can cause strains in the plastic region (resulting in permanent distortion), breakage, or fatigue. 
     There is, therefore, a need for a system to automatically lock folding components of an implement to eliminate exiting the towing vehicle and, thus, encourage use of the transport locks for implement transport. There is an additional need for a transport locking system that permits independent movement of the folding arms while in the locked, transport configuration. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a locking method and apparatus to secure a folding implement in a transport configuration. 
     Another object of this invention is to configure the transport locking system so an operator is not required to exit the towing vehicle, such as a farm tractor, to engage the lock. 
     An additional object of this invention is to configure the transport locking system to allow for independent movement between the folding arms and the main frame of the folding implement. 
     An automatic transport lock is suspended from the implement—either the main frame or the folding arms—during normal use. The transport lock is suspended in such a way as to include variable vertical displacement to compensate for any height adjustment needed over time from normal wear, and when the implement is disposed on uneven ground. When the implement is folded for transport, the arms engage the transport lock as a matter of course, the hydraulic cylinders used for folding the arms supplying all the work required to engage the locking mechanism to secure the folding arms for transport. After the implement is folded and the arms are locked for transport, the previously mentioned suspension system of the locks allows for articulation of the folding arms relative to the main frame, as well as allowing for articulation of the folding arms relative to each other. A pull rope is preferably utilized to unlock the mechanism from the tractor seat before opening the implement. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a towed agricultural rake in a nearly unfolded configuration with transport locks disengaged; 
         FIG. 2  is a top plan view of a towed agricultural rake in a folded, transport configuration with the transport locks engaged in their transport mode; 
         FIG. 3  is a perspective view, generally from the front of the implement, of the transport lock with its suspension system and in its engaged configuration; 
         FIG. 4  is a perspective view, generally from the front of the implement, of the transport lock in its disengaged configuration; 
         FIG. 5  is a perspective view, generally from the front of the implement, of the transport lock in its engaged configuration; 
         FIG. 6  is a perspective view, generally from the top, of the transport lock in its engaged configuration, and with a securing pin; 
         FIG. 7  is a perspective view, generally from the front of the implement, of the transport lock in its engaged configuration, and with the securing pin shown in  FIG. 6 ; 
         FIG. 8  is a perspective view, generally from the front of the implement, of the transport lock, just after disengaging by tension on a pull cord in a beginning of an unfolding operation; 
         FIG. 9  is a perspective view, generally from the front of the implement, of the transport lock with an electric solenoid actuator for unlocking the transport lock before unfolding the implement; and 
         FIG. 10  is a perspective view, generally from the front of the implement, of the transport lock with a rope or cord for unlocking the transport lock before unfolding the implement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein like reference numerals correspond to the same or similar parts throughout the drawings, the present invention includes a system for locking folding arms of a folding implement to the implement&#39;s main frame for purposes of transport. When a specific implement is shown ( FIGS. 1 and 2 ) or mentioned, an agricultural wheel rake is specified. However, it should be clearly understood, this invention is not limited to wheel rakes. Other folding implements such as planters, rippers, disks, sprayers, etc., may also make use of this invention to advantage. 
     In  FIG. 1 , a wheel rake  10  is shown in a substantially unfolded or open configuration. In  FIG. 2 , the wheel rake  10  is shown in its folded, narrow, transport configuration. Narrowing and widening are carried out using hydraulic cylinders  20 , as is well known by those of ordinary skill in the art. The hydraulic pressure and flow are provided by the prime mover, such as an agricultural tractor (not shown). 
     The folding implement preferably comprises a cart  25 , the cart  25  comprising ground engaging wheels  30  to provide support for the wheel rake  10 —though some folding implements do not require such support, and this invention is not limited to folding implements requiring ground engaging wheels  30  or the like for support—a main frame or towing bar  60 , and a tongue  70 , to which the implement  10  is hitched to a prime mover (not shown), such as an agricultural tractor. 
     For the purposes of this document, including the claims, a towable implement is hereby defined as an implement having at least one ground engaging wheel, skid, track, etc., independent of that of the prime mover by which the towable implement is towed. A towed implement is removably attached to the prime mover (e.g., via any known hitch) and is not permanently mounted thereto and is not entirely supported thereby. 
     The folding implement  10  further comprises folding arms  40  and folding linkages  50  by which the folding arms  40  are folded relative to the towing bar  60  for operation or transport. The folding arms  40  are operatively, pivotally affixed to the cart  25  and provide mounting for at least one implement unit, such as a rake wheel  45 , as shown in  FIGS. 1 and 2 , planter unit, sprayer nozzle, or tillage mechanism, etc. 
     The implement is towed by the prime mover, commonly an agricultural tractor. For the purposes of this document, including the claims, the following terms are formally defined: a forward direction  70  is defined as the usual direction of operation, and is indicated in  FIG. 1  by an arrow pointing in the forward direction  80 . The front of the implement  10  is defined as the end of the implement  10  toward the forward direction  80 . Likewise, the rearward direction is herein defined as the opposite direction as the forward direction  80 . The rear of the implement  10  is defined as the end of the implement  10  toward the rearward direction. Hence, the tongue  70  is disposed at the front of the implement  10 , while the wheels  30  are shown in  FIGS. 1 and 2  to be disposed at or near the rear of the implement  10 . The verb, narrow, is hereby defined as reducing the implement&#39;s  10  width in a direction perpendicular to the forward direction  70 . Folding inward is defined as synonymous with narrowing. The verb, widen, is hereby defined as increasing the implement&#39;s  10  width in a direction perpendicular to the forward direction  70 . Folding outward is defined as synonymous with widening. 
     Transport locking mechanism assemblies  100   a ,  100   b  are shown toward the front of the implement  10 , one set of assemblies  100   a ,  100   b  for each of the two folding arms  40 . The towing bar latch assembly  100   a  being operatively affixed to the towing bar  60 , while the folding arm latch assembly  100   b  is operatively affixed to a free arm end of the folding arms  40 . 
     More details of one set of transport locking mechanism assemblies  100   a ,  100   b  are illustrated in  FIG. 3 . An extension arm  310  may be required for some folding implements  10  to provide spacing between the main frame  60  of the cart  25  and the folding arm  40 . A latch mechanism  320  and crossbar assembly  330  work together to form the transport locking mechanism assembly set  100   a ,  100   b . The crossbar assembly, as shown in  FIG. 3 , may be operatively affixed to one of the folding arms  40  at the free end. 
     In order to effect the alignment of the latch mechanism  320  and crossbar assembly  330 , the latch mechanism  320  includes a suspension system  340  comprising, in a preferred embodiment, a leaf spring  350 , a shackle  360 , and an anchor  370 . Other valid embodiments include the use of tension, compression, or torsion springs. The present invention is not limited to a particular suspension system  340 . 
     The suspension system  340  is used to support the extension arm  310 , which is operatively, pivotably affixed to the main frame  60  by a hinged joint  380 . The extension arm  310  is free to pivot about the pin  390 . Support to keep the extension arm  310  from falling to its position of lowest potential energy due to gravity is provided by the suspension system  340 . 
     The vertical articulation of the extension arm  310  due to pivoting about the pin  390 , the suspension system  340 , and the V-shape of the latch mechanism  320  work together to allow alignment of the separate parts of the transport locking mechanism assemblies  100   a ,  100   b , especially under conditions of strain caused by the implement  10  sitting on uneven surfaces, or of normal wear and the effects of age and use. 
     Clearly, as those of ordinary skill in the art are well aware, the components of the transport locking mechanism assembly  100   a ,  100   b  may be reversed. In other words, the crossbar assembly  330  may be operatively affixed to the extension arm  310 , which may, in turn, be affixed to either the main frame  60  or one of the folding arms  40 . Similarly, the latch mechanism  320  may not be affixed to the extension arm  310 , but more or less directly to either the main frame  60  of the cart  25  or one of the folding arms  40 . In some applications, no extension arm  310  will be required. The present invention is not intended to be limited to the exact order shown in  FIG. 3 . 
     Details of the latch mechanism  320  and crossbar assembly  330  are illustrated in  FIG. 4 . A stationary portion  410  of the latch mechanism  320  is affixed to the extension arm  310 , if any. A latch element or pivoting portion  420  of the latch mechanism  320  is operatively, rotatably attached to the stationary portion  410  at a pin or bolt  430 . The latch element  420  of the latch mechanism  320  is free to pivot to allow a crossbar  440  to enter the latch mechanism  320 , then return to capture the crossbar  440  to secure the transport locking mechanism assemblies  100   a ,  100   b . The pivoting portion  420  of the latch mechanism  320  is biased by a spring (not shown) to hold it in its closed position to avoid accidental opening and the consequential release of the crossbar  440 . The crossbar  440  is operatively affixed to the folding arm  40  via a support structure  450 , which may take on many forms. 
     The latch mechanism  320  and crossbar assembly  330  are shown in the latched configuration in  FIG. 5 . The crossbar  440  is captured between the stationary portion  410  of the latch mechanism  320  and the latch element  420  of the latch mechanism  320 . In this configuration, the pivoting portion  420  is held in place by a biasing mechanism, such as a spring (not shown). 
       FIG. 6  shows the transport locking mechanism assemblies  100   a ,  100   b  in the same latched configuration as that of  FIG. 5 , but from generally the top. A pin  610  may be inserted to hold the pivoting portion  420  more securely in its latched configuration than with the spring alone. The pin  610  is shown in  FIG. 7  in a view, generally from the side. 
     The transport locking mechanism assemblies  100   a ,  100   b  are shown in an unlatched configuration in  FIG. 8 . The pivoting portion  420  has pivoted counterclockwise because of a force applied by the pull rope, cord, or cable  810  as pulled by the operator. Other methods of providing the force required to cause the pivoting portion  420  to pivot include a solenoid actuator  910 , as shown in  FIG. 9 , stepper motor, hydraulics, and/or pneumatics. The present invention is not limited to a single mechanism for providing this force. 
     A more complete view of an implement  10 , with the transport locking mechanism assemblies  100   a ,  100   b  of the present invention, is shown in  FIG. 10 . The pull rope, cord, or cable  810  is also shown for unlatching the latch mechanism  320 . 
     The above embodiments are the current preferred embodiments, but this invention is clearly not limited thereto. It is, therefore, apparent that many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.