Pin retainer assembly
TECHNICAL FIELD 
     This invention relates generally to a retainer assembly for a plurality of connecting pins and more particularly to a retainer assembly which locks the connecting pins in place in a first position of the retainer assembly and unlocks the connecting pins in a second position of the retainer assembly. 
     BACKGROUND ART 
     Drawbar assemblies are widely used in construction and farming industries to connect a powered work vehicle to a non-powered draft implement. In most applications, the forward portion of the drawbar assembly is rigidly connected to the rear portion of the vehicle and the draft implement is releasably connected in some manner to the rearward portion of the drawbar. This arrangement provides the flexibility of attaching a variety of draft implements to the work vehicle. In most applications, some type of quick connect device is utilized to join the draft implement to the drawbar assembly. A large number of these connecting devices use cylindrical connecting pins, which penetrate aligned holes in the drawbar and the draft implement, to complete the connection. In order to prevent damage to the draft implement and/or the work vehicle, it is very important to prevent inadvertent removal of the connecting pins. Various locking devices have been used in the past to prevent dislodgement of the connecting pins. 
     One type of pin locking device is disclosed in U.S. Pat. No. 3,794,357 issued to H. S. Frye on Feb. 26, 1974. In this patent, a hitch and drawbar arrangement are connected by a pin or bolt, and a lock bar prevents the connecting pin from working out of the hitch connection. Although this structure provides adequate locking of the connecting pin in a working position, the structure could not be used to lock a plurality of connecting pins in place. 
     Other types of pin retainers for hitch and drawbar assemblies are disclosed in U.S. Pat. No. 2,654,613 issued to C. L. Blair et al. on Oct. 6, 1953, and U.S. Pat. No. 4,394,031 issued to R. C. Barton et al. on July 19, 1983. In each of the above-noted patents, a single connecting pin or bolt is retained in a hitch connected position by a spring loaded plate member. The structure disclosed in these two patents would appear to provide sufficient locking of the single pin in each connection, but neither could be used to secure a plurality of connecting pins in a drawbar arrangement. 
     The present invention is directed to overcoming one or more of the problems as set forth above. 
     DISCLOSURE OF THE INVENTION 
     In one aspect of the present invention, a pin retainer assembly for a drawbar apparatus includes a plurality of connecting pins, each having an enlarged head, a retainer plate having a plurality of pin head receiving cavities, and means for securing the retainer plate to the drawbar apparatus. The pin retainer assembly further includes means for pivoting the retainer plate between first and second positions, with the connecting pins being secured by the retainer plate in the first position and the pins being free from securement in the second position. The pin retainer assembly also includes means for biasing the retainer plate toward the drawbar apparatus. 
     Draft implements are widely used in agricultural and construction industries, and these implements are commonly attached to a vehicle by a drawbar apparatus. Most commonly, a pin or bolt is utilized to make the releasable connection between the vehicle and the draft implement. Various locking devices are used to prevent the pins from becoming dislodged from the connected position. Many of these locking devices are difficult to manipulate and cause undue delay in the connecting and disconnecting process. Additionally, if an adjustable or angling drawbar apparatus is used, two or more connecting pins are generally employed, which complicates the connection and requires even more time to connect and disconnect the draft implement. Many such connections necessitate the use of both hands by the vehicle operator to release and/or remove the pins. This is inefficient since he must then manipulate the drawbar in a separate operation. 
     The present invention pin retainer assembly enables selected retention and release of multiple connection pins through single-handed manipulation thereof by a worker. The worker can then use his other hand to adjust the drawbar or perform other functions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic top plan view of a drawbar apparatus and a pin retainer assembly; 
     FIG. 2 is a diagrammatic side elevational view of the apparatus of FIG. 1, and taken generally along the lines II--II of FIG. 1; 
     FIG. 3 is a diagrammatic side elevational view, partly in section, of a pin retainer assembly of the present invention taken along lines III--III of FIG. 1; and 
     FIG. 4 is a diagrammatic top plan view taken generally along lines IV--IV of FIG. 3. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring to the drawings, a connecting pin retainer assembly 10, for a hitch or drawbar apparatus 12, includes first and second elongated hitch connecting pins 14 and 16, a retainer plate 18, a threaded fastener 20 for securing the retainer plate 18 to the drawbar apparatus 12, and means 22 for pivoting and manipulating the retainer plate 18 between a first position 24 and a second position 26, the second position 26 being shown in dotted line detail in FIG. 4. The pin retainer assembly 10 further includes means 27 for biasing the retainer plate 18 into forcible contact with the drawbar apparatus 12. Each of the connecting pins 14,16 has a first end portion 28 and a second end portion 30. The first end portion 28 of each pin 14,16 has an enlarged head 32 and a pin manipulating handle 34 above each head 32. 
     The retainer plate 18 has a central bore 36, a counterbore 38, and a pair of spaced apart pin head receiving cavities 40,42. The pivoting and manipulating means 22 includes a cylindrical bushing 44 positioned within the central bore 36 and held captive between an enlarged head 46 of the threaded fastener 20 and the drawbar apparatus 12. The drawbar apparatus 12 is preferably an adjustable type and includes a laterally adjustable drawbar 48 and a fixed drawbar support member 50. The drawbar 48 has a pair of vertically spaced upper and lower plates 52,54 which are adapted to receive a tongue or bar 56 of a draft implement (not shown). 
     The biasing means 27, which in the preferred embodiment is a coil spring 58, is positioned within the counterbore 38 and is compressed and held captive between the head 46 of the fastener 20 and the counterbore 38. The threaded fastener 20 is secured to the upper plate 52 and is positioned within the central bore 36. The first connecting pin 14 is adapted to penetrate the upper plate 52, the lower plate 54, and the support member 50, which is positioned between plates 52 and 54. The second connecting pin 16 is adapted to penetrate the upper plate 52, the lower plate 54, and the draft implement bar 56, which fits between the upper and lower plates 52,54. 
     The pivoting and manipulating means 22 provides that the retainer plate 18 is positionable between the first position 24 at which a portion of the connecting pins 14,16 are covered and secured by the retainer plate 18, and a second position 26 at which the pins 14,16 are free from the covering and securing relationship of the retainer plate 18. When the retainer plate 18 is in the first position 24, a portion of each pin connecting head 32 is contained within one of the cavities 40,42. The cavities 40,42 have an interior profile which is similar or complementary to the profile of a portion of the heads 32 of the connecting pins 14,16. The pivoting means 22 is positioned laterally substantially mid-way between the pin head receiving cavities 40,42. The pivoting and manipulating means 22 includes a U-shaped handle 60 which is secured to the retainer plate 18. The handle 60 extends over the threaded fastener and is used to move the retainer plate 18 between first and second positions 24,26. 
     The upper plate 52 of the drawbar 48 is supported by the drawbar support member 50. During lateral adjustment of the drawbar 48 from one position to another, the upper plate 52 slides on the support member 50. Interposed between the upper plate 52 and the support member 50 is a replaceable guide and wear plate 62. 
     INDUSTRIAL APPLICABILITY 
     The subject pin retainer assembly is particularly useful with agricultural and construction vehicles which have a drawbar assembly adapted to connect a draft implement to the vehicle. The drawbar 48 is connected to the vehicle (not shown) by a pivot connection and is laterally adjustable along the drawbar support member 50. At the desired position, a connecting pin 14 is inserted through aligned holes in the upper and lower plates 52,54 of the drawbar 48 and through another aligned hole in the drawbar support 50. This secures the drawbar 48 to the drawbar support 50 at a specific lateral position. 
     A tongue or bar 56 of a draft implement (not shown) is inserted between the upper and lower plates 52,54 and a second connecting pin 16 is inserted through other aligned holes in the plates 52 and 54 and the bar 56. This secures the draft implement to the vehicle. The pin retainer assembly 10 is then pivoted from the second or pin unlocked position 26 to the first or pin locked position 24. To accomplish this, the workman, using a single hand, lifts up on the handle 60 which pulls the retainer plate 18 upward and compresses the spring 58. With the plate 18 in the raised position, the handle 60 and retainer plate 18 are pivoted about the threaded fastener 20 and the bushing 44 to the first position 24. The handle 60 is then released and the plate 18 is forced downward by spring 58 until the plate 18 rests against the upper plate 52. In this position of the plate 18, a portion of heads 32 of the pins 14 and 16 are covered and contained within cavities 40 and 42 and are thereby secured against removal. 
     With the connecting pins 14,16 so secured by the retainer plate 18, they cannot be accidently removed or jarred loose by operation of the vehicle and draft implement. To disconnect the draft implement, or reposition the drawbar 48 along the support 50, the workman, using a single hand, lifts and rotates the retainer plate 18 to the unlocked position 26 and then removes either pin 14, pin 16, or both. When connecting, or disconnecting the draft implement, a workman can manipulate the bar 56 with one hand and the pins 14,16 and retainer assembly 10 with the other hand. This eliminates the need of more than one workman. 
     Other aspects, objects, and advantages of this invention can be obtained from a study of the drawings, the disclosure, and the appended claims.