Abstract:
A coupling for coupling first and second members. The members define an opening for extended and circular counterparts. The counterparts turn on the members and each other while the members contact the counterparts to urge them together. The counterparts, one after another between the members, move and release the members.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 08/421,405, filed Apr. 13, 1995 and entitled “Extensible Connector With Lock Mechanism”now abandonded, which is a continuation-in-part of U.S. patent application Ser. No. 08/110,241, filed Aug. 23, 1993 and entitled “Pressure Release Systems”, now abandonded, which is a continuation-in-part of U.S. patent application Ser. No. 07/867,984, filed Apr. 13, 1992 and entitled “Pressure Release Systems”, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to vehicle tow bars, and more particularly, to foldable and collapsible tow bars which are easily attached and removed from the towed and towing vehicles. 
     1. Field of the Invention 
     The tow bar assembly includes telescoping frame members having ends attached to an apex member which in turn mounts to a connecting member which is attached to a towing vehicle. The other ends of the frame members are telescopically adjusted and are secured to the bumper or frame of the towed vehicle. Each telescoping frame member has a pair of telescopic members and a locking mechanism for adjustably securing the members for ease of attachment to the vehicles and for providing a quick release for the frame members for detachment from a vehicle. 
     2. Description of the Prior Art 
     Tow bars are known in the prior art. Some are conventional in the sense that they are either single bars or are an A-frame type which are rigidly mounted to the vehicles. Alternatively, collapsible tow bars are known which are arranged to be folded when not in use for storage purposes. Also, the prior art discloses tow bars which include telescopically adjustable members which are secured by locking members and which members are adapted for remote actuation. 
     U.S. Pat. Nos. 4,978,134; 5,071,153 and 5,147,095 teach the universal mounting of collapsible-telescoping tow bar members. 
     U.S. Pat. Nos. 5,011,176; 3,984,121; 4,861,061; 2,484,751; 3,492,022; 2,639,160 and 3,158,387 disclose pressure release and/or extension and retraction locking capabilities for telescoping tow bar members. U.S. Pat. No. 3,984,121 discloses a spring biased pivotal mechanism for a locking pin which is adaptable for insertion in complementary openings to adjust and secure telescoping tow bar members. U.S. Pat. No. 2,639,160 discloses an eccentric roller/cylinder member, an eccentric lobe portion which engages complementary notches when rotated to lock telescoping bar members in place. U.S. Pat. No. 3,158,387 discloses cam locking means to secure tow bar telescoping members. 
     U.S. Pat. No. 2,914,343 discloses a tow bar mounting attached to a vehicle frame under the bumper and telescoped such that it can be retracted to conceal the mount. 
     U.S. Pat. No. 3,806,162 discloses a clamp attachment to a bumper for a universal tow bar mounting. 
     U.S. Pat. No. 2,667,366 discloses a remote pin release mechanism to permit actuation for locking and unlocking adjustable telescoping tow bar members. 
     While the tow bars described in the above-referenced patents provide some advantages, they do not permit the overall versatility of the present invention. For example, in the prior art structures, there is considerable difficulty in releasing the locking mechanism for the tow bar members especially when the towed and towing vehicles are stopped at a position where there is a tension force on the tow bar members. In such a situation it is necessary to dismount the towing vehicle to manually force disengagement of the locking mechanism by utilizing a hammer or the like. 
     SUMMARY OF THE INVENTION 
     The invention is directed to an easily attached and detached tow bar assembly that avoids the problems of the prior art. 
     The invention includes a collapsible and universal mount for the tow bar for ease of storage when not in use. The invention further includes adjustable telescoping frame members for attachment and detachment to towed and towing vehicles regardless of their static position relative to each other. 
     Each adjustable telescoping tubular frame member includes a pair of telescopic members and an easily actuated release mechanism for securing the telescopic members to each other so that they can be easily released either remotely or otherwise despite the fact that the vehicles may cause considerable tension forces on the bars. For example, the vehicles may be parked on a hill when it is desired to unhook the tow bar assembly. In this case, it is clear that any release mechanism will be under considerable tension forces making it difficult to effect release without the use of a force applying implement or the like. 
     Another embodiment of the invention uses roller release members which can be lever actuated. The roller release members cooperate with one another and with the telescopic members such that only finger pressure is needed to release the members from notches in the members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a tow bar assembly showing telescopically adjustable frame members; 
     FIG. 2 is a partial vertical section of a first embodiment of a pressure release roller locking arrangement; 
     FIG. 3 is a plan view of a roller locking arrangement similar to that shown in FIG. 2; 
     FIGS. 4-6 are partial vertical sections of telescopic members having different stops for limiting the extension and the retraction of the telescoping members; 
     FIGS. 7-12 are side elevations showing different notch configurations; 
     FIG. 13 is a partial vertical section showing variations of the invention; 
     FIG. 14 is a plan view of another embodiment; 
     FIG. 15 is a partial vertical section of a locking arrangement similar to FIG. 2 showing a roller release hinge pivot arranged opposite to FIG. 2; 
     FIG. 16 is a side, sectional view of an alternative embodiment of a tow bar locking arrangement. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings in detail, FIG. 1 discloses a tow bar assembly  15  having a pair of frame members F connected to an apex member  13  which can be operatively connected to a towing vehicle (not shown). The other end of each frame member F has a pivot member  6  attached thereto which can be operatively connected to a towed or trailing vehicle (not shown). The tow bar assembly  15  consists of two telescoping tubular frame members F. One of the tubular frame members F is pivotally connected to apex member  13  for movement in a substantially horizontal plane. The other tubular frame member F is fixed to apex member  13 . 
     The trailing end of each frame member F is connected to the bumper  29  of the towed vehicle and, with the elements to be described, form universal connections between the frame members and the vehicle bumper. Each universal connection comprises spaced-apart eye bolt members  4  fastened to the bumper  29  by nuts or the like with the eyes of the eye bolts being disposed on a substantially horizontal axis. Interposed between the eye bolts is a connecting member  5  having both horizontally and vertically disposed apertures. The horizontally disposed aperture is interposed between the eye bolts and is journaled therebetween by a journal pin  7 . This permits pivotal movement of the connecting member  5 . The vertically disposed aperture of member  5  is connected to pivot member  6  of a frame member. A vertically disposed journal pin  8  extends through the vertical apertures in members  5  and  6  and is secured by any suitable means. The above-described connection between the members  5  and  6  permits pivotal movement of the pivot member  6  in a horizontal plane. The above-described connection between members  4 ,  5  and  6  permits a universal connection between each frame member F and vehicle bumper  29  so that tow bar assembly  15  is free to move in both horizontal and vertical planes with respect to the bumper. 
     While only one frame member F has been described as attached to the vehicle bumper, it is readily apparent that the other frame member F of the tow bar assembly  15  is attached to the bumper in a laterally spaced relationship with like connecting means. 
     The universal connection between each frame member and the vehicle bumper permits multiple types of relative motion between the frame members and bumper thus reducing the strain or stress either to the bumper or the respective frame members especially when towing over uneven or bumpy terrain. 
     The universal connections between the frame members and the bumper also permit easy mounting, dismounting and collapsible storage for tow bar assembly  15 . Frame members F can be easily disconnected from eye bolts  4  by removing journal pins  7 . Thereafter, frame members F can be folded together by virtue of their pivotal connection to apex member  13 , and stowed in a convenient location. Alternatively, only one frame member need be disconnected and swung together in adjacent relationship with the other frame member and both frame members may be swung in parallel relationship with the vehicle bumper by virtue of the vertically disposed pin  8  to a storage position. Additionally, both frame members may be swung on journal pins  7  in a vertical plane to an upright position against the vehicle for storage. 
     Each frame member F is comprised of an outer or first tubular telescopic member  1  and an inner or second tubular telescopic member  2  which permit axial adjustment of the frame members for ease of connection between the towing and towed vehicles. Each frame member F has a locking means interposed between telescopic members  1  and  2  thereof for locking the telescopic members in various adjusted positions and for providing easily releasable means for unlocking the telescopic elements under a variety of conditions. 
     FIGS. 2,  3  and  15  illustrate a preferred embodiment of a high pressure roller release mechanism  26 . FIGS. 3 and 15 show a first tubular telescopic member  1  having a given dimension and a short tubular extension member  27  attached to the first tubular telescopic member  1  at one end. The tubular extension member  27  has an outer dimension less than the inner dimension of first tubular telescopic member  1 . 
     A second tubular telescopic member  2  having a second surface is slidable within first tubular telescopic member  1  and tubular extension member  27  and has a raised shoulder  28  adapted to be engaged with one end of tubular extension member  27 . The first tubular telescopic member  1  has a notch  30  intermediate its ends with the notch  30  having a first surface formed by an enlarged abutment  31  at one end. The abutment  31  is formed by an abutment assembly comprising a pair of metal plates attached by conventional means, such as welding, to each side of the tubular member  1  adjacent the notch  30 . The plates are positioned such that one end of each plate extends beyond the end of the notch  30  so that when the rollers  17 A and  17 B are in a locking position in the notch  30 , the right most roller  17 A, as shown in FIG. 2, contacts the ends of the plates rather than the notch end formed in the tubular member  1 . These plates help prevent wear of the notch end in the tubular member  1  and can be replaced when they become worn. Still referring to FIG. 15, there is illustrated a pivot pin  19  fastened to the upper portion of tubular extension member  27  adjacent the notch  30 . Pivot plates  18  are rotatably mounted on pivot pin  19  on opposite sides of first tubular telescopic member  1 . 
     Rotatable elements or cylindrical movable members, such as roller members  17 A and  17 B, are each mounted and freely rotatable between pivot plates  18 . The pivot plates  18  thus act as a roller holder to move the rollers  17 A and  17 B in unison. Roller  17 A may be smaller in diameter than roller  17 B and roller  17 A has a handle  32  attached thereto, as shown in FIG. 3 of the drawings. The pair of roller members  17 A and  17 B are shown as in frictional contact and dimensioned so they are also in frictional contact with the raised shoulder  28  (second surface) and enlarged abutment  31  (first surface) when located within notch  30 . 
     When the roller members  17 A and  17 B are within notch  30 , they lock first and second tubular telescopic members  1  and  2  in an extended relationship. The release of the tubular telescopic members is effected by rotating roller member  17 A with handle  32  thereby causing the roller members to ride up abutment  31 , i.e., the ends of the plates extending into the notch, and the wall of shoulder  28  until the roller members exit the upper open end of notch  30  thereby freeing tubular telescopic members  1  and  2  to telescope. It will be appreciated by those skilled in the art that the different diameter frictional contact roller members provide a high leverage release mechanism when used in conjunction with the notch walls. 
     FIG. 2 is a mirror image of FIG.  15 . However, in this arrangement, the abutment is eliminated allowing direct contact of roller member  17 A with first tubular member  1 . 
     A tow bar with an alternative release mechanism embodiment  299  is shown in FIG. 16 of the drawings. In this embodiment  299 , the rollers  17 A and  17 B are rotatably carried between two spaced-apart pivot plates  300 . A connecting plate  301  extends between the two pivot plates  300  and joins the two pivot plates  300  together. An abutment  31  is provided which is formed by an abutment assembly having two plates  302  attached to opposite sides of the outer telescopic member  1 . The ends of the plates  302  extend beyond the notch wall so that in the engaged position shown in FIG. 16, the right most roller  17 B contacts the abutment  31  of the first telescopic member  1 . The connecting plate  301  is sized such that the pivot plates  300  maintain a movable clearance from the plates  302  of the abutment  31 . 
     Two circular members  303 , such as two spaced-apart washers, are fastened on top of the first telescopic member  1  forward of the notch  30 , as shown in FIG. 16. A rod or pin  304  extends between the two circular members  303 , for example, through the holes in the washers. A spring  306  is mounted on the pin  304  and a distal end  308  of the spring  306  extends toward the notch  30 . The distal end  308  of the spring  306  contacts the top side of a pressure plate  310  which is attached to, and extends between, the two pivot plates  300 . The force of the distal end  308  of the spring  306  causes the roller holder to be biased in a counterclockwise direction until the connecting plate  301  contacts the spring  306  or circular members  303 , thus determining the height of the rollers  17 A,  17 B in relation to each other and the members  1  and  2 . The rollers  17 A,  17 B hitting the bottom of the notch  30  complete the positioning of the roller holder and the rollers  17 A,  17 B. The horizontal positioning of the rollers  17 A and  17 B can be further individually changed by moving the holes in pivot plates  300  through which the rollers  17 A,  17 B pass. The rollers can be positioned in parallel with the bottom of the notch  30  or either can be above or below the other and can be the same size. The distal end  308  of the spring  306  between the connecting plate  301  and pressure plate  310  helps prevent over pivoting of the roller holder. While the embodiment  299  described above utilizes two rollers, it could also be embodied with, for example, three triangularly positioned rollers in the holder. 
     A pry bar assembly  314  is mounted on the outer tube  1 . The pry bar assembly  314  includes two nuts  316  attached, for example, by welding, to a pry bar  318 . A rod or pin  320  extends through the nuts  316  and is welded or fastened to the top of the plates  302  of the abutment  31 , thus allowing pivotal movement of the pry bar  318 . A first end  322  of the pry bar  318  is located under the connecting plate  301  of the roller holder. In order to assist removing the rollers from the notch  30 , a circular handle can be attached to one of the rollers, similar to the handle  32  shown in FIG. 3 of the drawings. By turning the circular handle, the roller associated therewith turns and crawls up the walls of the notch, thus exiting the notch. The handle can include a slot into which a key or small bar may be inserted to help provide turning leverage to turn the roller. As shown in FIG. 16, by exerting a downward pressure on the second end  324  of the pry bar  318 , the first end  322  pivots upwardly contacting the underside of the connecting plate  300  and causing the rollers to move up the notch substantially parallel with the notch walls. This helps prevent roller slippage and roller holder binding and helps prevent twisting of the roller holder against the rollers. 
     While the rollers shown in the preferred embodiments have a smooth outer surface, notched rollers, such as long, gear-like members could also be used. In such an embodiment, the shoulder of the second telescopic member and the ends of the abutment plates extending beyond the notch walls would preferably have notches so that the teeth on the geared rollers would engage the notches to help move the geared rollers out of the notch. Additionally, the rollers would not have to be held in a roller holder but simply be two individual rollers insertable into the notch. Alternatively, the rollers can be embodied as roller bearings. 
     FIGS. 4 and 5 illustrate limiting stop arrangements for telescopic members  1  and  2 . When roller members  17 A and  17 B are released from notch  30 , telescopic members  1  and  2  may telescope. An eye bolt  43  is located within the telescopic members and has stops  44  and  45  at each end, respectively. Upon release of the rollers from notch  30 , second telescopic member  2  can telescope to the left, as shown in FIG. 4, until stop  45  strikes an end plate  46 . The second telescopic member  2  can telescope to the right until end plate  46  strikes stop  44 . The eye bolt  43  is secured or maintained in place relative to first telescopic member  1  by a pin  43 A which can be inserted through an aperture in first telescopic member  1  and connected with stop  44 . 
     FIG. 6 illustrates a roller release mechanism wherein notches  30  are located in both telescopic members  1  and  2  rather than only in first telescopic member  1  as shown in FIGS. 2 and 15. 
     FIGS. 7 and 8 show various modified roller release mechanisms utilized for special purposes. If walls  114  of notch  30  are angled, as shown in FIG. 7, the forces on the rollers will cause roller members  17 A and  17 B to rotate to relieve the forces. The amount of force which will cause the rollers to rotate is determined by the angle of the notch wall and the resilience of coil spring  115 . This causes the roller members  17 A and  17 B and the roller holder  83  to move toward pivot pin  19 . To minimize this problem, both notch walls  114  are angled one-half as much, as in FIG.  7 . The notch  30  in FIG. 8 has walls  114  which are angled at the bottom and are parallel at the top. This will cause roller holder  83  to move slightly when enough force is applied. It could be used to set off a switch indicating that enough force has been applied. When the roller members get to the parallel walls at the top, they will go no further unless the roller release lever  116  shown in FIG. 10 is turned to relieve the force on the roller members. FIG. 8 shows two angles on one side only. It would take twice as much pressure to move the roller members in FIG. 8 than in FIG.  7 . FIG. 9 has curved notch walls. This causes the roller members to move with graduating amounts of force until they reach the parallel walls at the top of the notch. The curved walls could also be curved all the way to the top of the notch until enough force causes the roller members to roll out of the notch and relieve the force, as in FIG.  9 . FIG. 10 has cushioning in both directions, yet the roller members have limited lateral movement. With this release mechanism, the hitch would unhook completely when released and would release in both directions. 
     In FIG. 13, the locking and release mechanism  3  or roller release mechanism  26  can be on top. If the release mechanism  26  is on top, roller members  17 A and  17 B, or pin  9  and plate  20 , must have a lift spring, such as a torsion spring  60  or a leaf spring  61 , to push them into aperture  10  when cam  49  is released. The bias means  47  must be more rigid than the lift spring so that when cam  49  is engaged, pin  9  falls into aperture  10 . In FIG. 13, torsion spring  60  assists in moving the roller members  17 A and  17 B out of the notch when cam  49  is released. 
     The device shown in FIG. 14 has a roller release for release in both directions. Approximately 2″ in one direction and 4″ in the other direction. This hitch telescopes and swivels laterally and has force release in both directions. The guides  96  of a cushion tube  150  along with pin  130 , guide tube  150  straight as a vehicle is backed up to line up for the roller lock. Guides  96 ′ are mounted on the hitch frame. When roller members  17 A and  17 B roll out, the hitch can go in either direction. Tube  150  is tapered at the right end, as shown in FIG. 14, to enter roller members  17 A and  17 B. The tube  150  does not hurt the roller holder  83  because the roller holder  83  is under the hitch frame, top and bottom. This hitch can be pulled from the left for a pick-up or from the right on a cultivator or an anhydrous trailer. The tapered end  151  at the right could be lengthened and pulled. The hitch would lock when the vehicle is pulled ahead. The hitch has safety stops in both directions. 
     While a number of embodiments of the invention are described in detail herein, it will be appreciated by those skilled in the art that various modifications and alternatives to the embodiments could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements are illustrative only and are not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.