FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     SEQUENCE LISTING OR PROGRAM 
     Not Applicable 
     BACKGROUND 
     1. Field of Invention 
     This invention relates to hitches used to join together multiple pieces of equipment, such as a plurality of rotary lawn mowers, so that they travel as a single unit. 
     2. Description of Prior Art 
     Three desirable features in a gang mower are: wider cutting swath, flexibility to follow the terrain, and maneuverability. A wider cutting swath reduces the time required to cut a given area making them desirable to maintain large lawns. Designs that include separate components that have the ability to move independently of each other result in a more even cut. The assembly should be easy to maneuver, in both forward and reverse, on turns, and in tight places. Prior art fails to successfully combine these three attributes in a single unit. 
     Several patents such as: U.S. Pat. No. 3,608,284 issued to Leon Paul Erdman on Sep. 28, 1971; U.S. Pat. No. 4,063,748 issued to Richard H. Schmidt on Dec. 20 1977; U.S. Pat. No. 7,287,363 issued to David Lawrence Phillips on Oct. 30, 2007; require special components. My invention can utilize commercially available off-the-shelf components. These prior art designs are meant to travel in only one direction while my invention performs well in either direction. The towed mowers in U.S. Pat. No. 3,608,284 and U.S. Pat. No. 4,063,748 are designed to be pulled. 
     Several patents such as: U.S. Pat. No. 3,514,126 issued to William H. Fuss May 26, 1970; U.S. Pat. No. 4,079,960 issued to Raymond M. Carson on Mar. 21, 1978; U.S. Pat. No. 4,123,082 issued to Joe D. Conner on Oct. 31, 1978; U.S. Pat. No. 4,637,625 issued to John B. Blackwell on Jan. 20, 1987; U.S. Pat. No. 4,744,580 issued to Charles C. Ryan on May 17, 1988; U.S. Pat. No. 5,423,565 issued to Frederick Smith on Jun. 13, 1995; U.S. Pat. No. 7,347,036 issued to Easley, Jr.; J. Alexander on Mar. 25, 2008; have towed mowers that are susceptible to jackknifing when traveling in reverse. 
     Several patents such as: U.S. Pat. No. 4,815,259 issued to Wayne Scott on Mar. 28, 1989; U.S. Pat. No. 4,870,810 issued to Donald G. Gordy on Oct. 3, 1989; U.S. Pat. No. 4,896,485 issued to Donald G. Gordy on Jan. 30, 1990; U.S. Pat. No. 5,851,020 issued to Lawrence A. Godwin Dec. 22, 1998; have a group of towed mowers that is susceptible to jackknifing when traveling in reverse. Furthermore, each individual mower in the groups is susceptible to jackknifing when traveling in reverse. 
     Several patents such as: U.S. Pat. No. 3,757,500 issued to Marnie C. Averitt on Sep. 11, 1973 (preferred embodiment); U.S. Pat. No. 3,832,834 issued to George E. Kovacs on Sep. 3, 1974; have a group of mowers that is susceptible to jackknifing when traveling in reverse. 
     OBJECTS AND ADVANTAGES 
     Accordingly, in addition to providing the common desirable features including wider cutting swath, and more even cut that results from individual decks that can follow irregular terrain, several objects and advantages of my invention are: 
     (a) the ability to travel forward and reverse without jackknifing; 
     (b) the option of mounting the non-propelled mowers towards the rear or the front of the propelled mower; 
     (c) attaching and detaching is simple, for storage or to free the components for independent use; 
     (d) conventional commercially available off-the-shelf components can be used; 
     (e) the option to attach as many non-propelled units as desired. 
     SUMMARY 
     The hitch of my invention connects a propelled mower assembly with one or more non-propelled mower assemblies. The hitch allows the propelled mower to push or pull the non-propelled mowers without jackknifing. The mower decks are free to follow the terrain independently of each other. The desired individual movement includes roll relative to a longitudinal axis of each deck, and pitch relative to a lateral axis of each deck. The non-propelled mower decks are rigidly held by the hitch relative to a vertical axis of each non-propelled mower deck. The yaw movement of the non-propelled mower is coaxial with the vertical axis of the propelled mower assembly. The hitch does not allow the non-propelled mower assembly to pivot in the yaw direction relative to its own vertical axis. My invention solves the problem of maneuverability experienced by prior art. The entire assembly combines the quality cut of individual mowers with the maneuverability of a single machine. The unit performs equally well in the forward or reverse travel directions. The hitch is simple. The hitch can be made to fit existing mowers of various designs. The mower decks can be located close together minimizing the amount of overlap required thereby maximizing the cutting swath. Having the decks close together also improves maneuverability, storage, and transportation because the entire machine has a smaller footprint. 
    
    
     
       DRAWINGS 
       Drawing Figures 
         FIG. 1  is a top view showing the hitch connecting two non-propelled mowers to a propelled mower. 
         FIG. 2  is a view showing the control arm looking straight on. 
         FIG. 3  is a top view of the control arm. 
         FIG. 4  is a detailed top view of the bracket assembly and joint assembly. 
         FIG. 5  is a detailed top view of the control arm and joint assemblies. 
         FIG. 6  is a detailed exploded isometric view of the bracket assembly and joint assembly. 
         FIG. 7  is an example of an alternate embodiment.  FIG. 7  is a top view showing the hitch connecting two non-propelled mowers to a propelled mower. This alternate embodiment utilizes y-arms in lieu of bracket assemblies shown in the preferred embodiment. This alternate embodiment utilizes the same control arm used in the preferred embodiment. 
     
    
    
     REFERENCE NUMERALS IN DRAWINGS 
     
         
         
           
               20  propelled mower assembly 
               22  mower deck of propelled mower assembly 
               24  wheel of propelled mower assembly 
               30  non-propelled mower assembly 
               32  mower deck of non-propelled mower assembly 
               34  wheel of non-propelled mower assembly 
               40  control arm 
               50  bracket assembly 
               52  longitudinal component of bracket assembly 
               54  lateral component of bracket assembly 
               60  joint assembly 
               62  joint stud 
               64  joint nut 
               66  joint nut 
               68  joint nut 
               70  y-arm bracket assembly 
               72  y-arm main beam 
               74  y-arm brace beam 
           
         
       
    
     DETAILED DESCRIPTION 
     Description— FIG. 1 Through 6 —Preferred Embodiment 
     The hitch shown in  FIG. 1  joins a non-propelled mower assembly  30  to a propelled mower assembly  20 . The hitch is comprised of two parts. 
     The first part of the hitch is a bracket assembly  50  which is securely fastened to the mowing deck of the propelled mower  22 . A joint assembly  60  connects the bracket assembly  50  to the non-propelled mower assembly  30 . The joint allows the non-propelled mower assembly  30  to roll relative to its longitudinal axis. The joint also accommodates a wide range of angular motion relative to its lateral axis, permitting the non-propelled mower assembly  30  to pitch as necessary relative to its lateral axis. 
     The second part of the hitch is a control arm  40 . One end of control arm  40  is fastened to the propelled mower assembly  20  via a joint assembly  60 . The other end of control arm  40  is fastened to the mower deck of the non-propelled mower  32  via a joint assembly  60 . 
     The two joint assemblies  60  located on the non-propelled mower assembly  30  allow the non-propelled mower assembly  30  to roll relative to its longitudinal axis in order to follow the terrain. Furthermore, the two joint assemblies  60  located on the non-propelled mower assembly  30  allow sufficient angular movement that allow the non-propelled mower assembly  30  freedom to pitch relative to its lateral axis in order to follow the terrain. However, the two parts of the hitch work together to prevent the non-propelled mower assembly  30  from moving in the yaw direction relative to its vertical axis. 
       FIG. 6  is a detailed exploded isometric view of the bracket assembly  50  and joint assembly  60 . Joint stud  62  is a length of threaded rod installed in a hole of the mower deck of non-propelled mower  32 . The location of the hole that receives the stud must match the location of the corresponding hole in lateral component of bracket assembly  54 . That stud is rigidly held onto the mower deck by tightening joint nut  68  located on the inside of the deck and joint nut  66  located on the outside of the deck. Joint stud  62  protrudes beyond joint nut  66 . The longitudinal component of bracket assembly  52  is rigidly fastened to the mower deck of propelled mower assembly  22  by suitable means such as welding. The lateral component of bracket assembly  54  is rigidly fastened to the longitudinal portion of the bracket assembly  52  by suitable means such as welding. The lateral component of bracket assembly  54  is rigidly fastened to the mower deck of propelled mower  22  by suitable means such as welding. The lateral component of bracket assembly  54  has a hole through which the protruding joint stud  62  is inserted. The location of the hole must match the location of the protruding joint stud  62 . The diameter of the hole is big enough to provide a loose fit for joint stud  62  but small enough so that nuts  64  and  66  can not pass through the hole. Joint nut  64  is installed onto the end of joint stud  62  without making it tight. Joint nut  64  is left loose to create a joint that accommodates a wide range of angular motion relative to the longitudinal and lateral axes of the non-propelled mower assembly  30 , permitting the non-propelled mower assembly  30  to roll and pitch over the terrain as necessary. 
       FIG. 2  is a straight-on view of the control arm  40  and its two corresponding joint assemblies  60 . In the preferred embodiment all joint assemblies  60  are identical. The length of the control arm  40  is determined by factors such as the design of mower assemblies being used and the locations of joint assemblies  60  on the mower assemblies for attaching control arm  40 . A critical consideration when designing the control arm is the amount of desired overlap between the decks of the propelled and non-propelled mowers. The orientation of the control arm relative to horizontal is also determined by factors such as the design of mower assemblies being used and the locations of joint assemblies  60  on the mower assemblies for attaching control arm  40 . 
       FIG. 3  is a top view of the control arm  40  and its two corresponding joint assemblies  60 . In the preferred embodiment all joint assemblies  60  are identical. The length of the control arm is determined by factors such as the design of mower assemblies being used and the locations of joint assemblies  60  on the mower assemblies for attaching control arm  40 . A critical consideration when designing the control arm is the amount of desired overlap between the decks of the propelled and non-propelled mowers. The orientation of the control arm relative to lateral axis is also determined by factors such as the design of mower assemblies being used and the locations of joint assemblies  60  on the mower assemblies for attaching control arm  40 . 
       FIG. 4  is a top view of the bracket assembly  50  and its corresponding joint assembly  60 . The lateral component of bracket assembly  54  is rigidly fastened to the mowing deck of the propelled mower  22  by suitable means such as welding. The longitudinal component of bracket assembly  52  is rigidly fastened to the mowing deck of the propelled mower  22  by suitable means such as welding. The lateral component of the bracket assembly  54  is rigidly fastened to the longitudinal portion of the bracket assembly  52  by suitable means such as welding. Joint stud  62  of joint assembly  60  is rigidly held onto mower deck of non-propelled mower assembly  32  by tightening joint nut  68  and joint nut  66 . Joint stud  62  protrudes beyond joint nut  66 . Joint nut  64  is installed onto joint stud  62  but not completely tightened leaving some play that accommodates a wide range of angular motion relative to longitudinal axis of the non-propelled mower assembly  30 , permitting the non-propelled mower assembly  30  to pitch and roll as necessary. The lateral locations of bracket assembly  50  on mower deck  22  and its corresponding joint assembly  60  on mower deck  32  are chosen to provide the desired overlap of cutting swaths. 
       FIG. 5  is a top view of the control arm  40  and its two corresponding joint assemblies  60 . In the preferred embodiment all joint assemblies  60  are identical. Details of one of the assemblies is shown in  FIG. 5  where the control arm connects to the propelled mower assembly  20 . Joint stud  62  of joint assembly  60  is rigidly held onto the propelled mower assembly  20  by tightening joint nut  68  and joint nut  66 . Joint stud  62  protrudes beyond joint nut  66 . Joint nut  64  is installed onto joint stud  62  but not completely tightened leaving some play that accommodates a wide range of angular motion relative to the lateral and longitudinal axes of the non-propelled mower assembly  30 , permitting the non-propelled mower assembly  30  to pitch and roll as necessary. Joint stud  62  is a piece of threaded rod which is loosely fastened to the control arm  40 . The joint stud  62  fits in a hole in the control arm  40  to create a joint that accommodates a wide range of angular motion relative to the lateral axis and the longitudinal axis of the non-propelled mower assembly  30 , permitting the non-propelled mower assembly  30  to pitch and roll as necessary. 
     Additional Embodiments 
     In the preferred embodiment there are various possibilities regarding the location of the joints that connect the hitch to the propelled and the non-propelled mowers. The exact location will depend on several factors such as the mowers chosen. 
     As an alternative to having the hitch attach at the deck of the propelled mower, a y-arm arrangement could be substituted for that portion of the hitch. The y-arm has at least three connecting points, two of which could be on the propelled mower as shown in  FIG. 7  and the third point would be on the non-propelled mower. If desired, the y-arm could connect to the non-propelled mower at two points and the propelled mower at one point. The y-arm embodiment of the invention possess all the advantages of the preferred embodiment. 
     The hitch shown in  FIG. 7  utilizes the same control arm  40  as the preferred embodiment. However, a y-arm bracket assembly  70  is substituted for the bracket assembly in the preferred embodiment (see bracket assembly  50  in  FIG. 1 ). The y-arm is connected the propelled mower assembly  20  using two joint assemblies  60 . The joint assemblies  60  allows roll motion of the non-propelled mower assembly  30 . The joint also accommodates a wide range of angular motion relative to a lateral axis of the non-propelled mower assembly  30 , permitting the non-propelled mower assembly  30  to pitch freely. However, the y-arm bracket assembly  70  and control arm  40  work together to prevent the non-propelled mower assembly  30  from moving in the yaw direction relative to the vertical axis of the non-propelled mower assembly  30 . 
     The second part of the hitch is a control arm  40 . One end of control arm  40  is fastened to the propelled mower assembly  20  via a joint assembly  60 . The other end of control arm  40  is fastened to the mower deck of the non-propelled mower  32  via a joint assembly  60 . The two joint assemblies  60  located on the non-propelled mower assembly  30  allow the non-propelled mower assembly  30  to roll relative to the longitudinal axis of the non-propelled mower assembly  30  in order to follow the terrain. 
     Materials and Components 
     The movement at joint assemblies  60  is primarily rolling movement relative to the longitudinal axis and pitch movement relative to the lateral axis. Any joint design that permits the required movements can be used. The preferred embodiment uses horizontal and vertical studs. For example, properly oriented hinges could be used, or a combination of studs and hinges. A ball and socket joint could also be used if it provides the required rotational and angular motion. The preferred embodiment uses the same joint at all locations. The same joint is used for several reasons including: uniformity, and the ability to accommodate varying mounting positions required by the devices being connected. 
     Common materials are used in the preferred embodiment. Any suitable rigid linear material can be used for control arm  40 . Metal tubing can be used for control arm  40 , flattened and bent at each end to accommodate joint assemblies  60 . Each flattened end has a hole of sufficient diameter that receives the joint stud  62 . The hole is of sufficient diameter to permit the rotational and angular movement requirements. 
     Bracket assembly  50  was attached by welding, however, other suitable means for attachment could include nuts and bolts, requiring only minor variations. 
     Joint nut  64  can be installed using a thread locking compound or the nut could be of the self locking type. 
     The drawings include wheels on the non-propelled mower assemblies for clarity and completeness, but the wheels are not part of the invention. There are other choices for supporting the non-propelled mower assemblies including: wheels on fixed axles, caster wheels, and skids.
A hitch that connects one propelled mower assembly to one or more non-propelled mower assemblies, allowing the non-propelled mower to be pushed or pulled without jackknifing, while the individual mower decks are free to follow the terrain independently of each other. The hitch has two rigid connectors pivotally attached to and interconnecting the propelled mower and the non-propelled mower. Each mower deck can move freely relative to its lateral and longitudinal axes independent of each other.