Abstract:
A safety locking coupling assembly in which pull rings on the female coupling unit of a male coupling unit/female coupling unit assembly serve both to release the coupling assembly and to maintain the coupling assembly locked against unintentional disconnection. The pull rings are attached to cam arms which engage the male coupling unit to lock the coupling assembly and are disengaged from the male coupling unit to release the coupling assembly. In the locked condition of the coupling assembly, the pull rings abut against ears on the housing of the female coupling unit to oppose unintended movement of the cam arms from the locked position of the cam arms to the released position of the cam arms. Upon intentional removal of the pull rings from abutment with the ears by an operator and pulling on the pull rings, the cam arms can be moved from the locked position of the cam arms to the released position of the cam arms to disconnect the coupling assembly.

Description:
This application is a Continuation-in-Part of Application Serial No. 08/903,814, filed Jul. 31, 1997, pending. 
    
    
     TECHNICAL FIELD 
     The present invention relates, in general, to couplings for connecting hoses and other conduits which carry fluids and, in particular, to a fluid coupling having a safety latching mechanism which can be operated to quickly connect and disconnect hoses and other conduits. 
     BACKGROUND OF THE INVENTION 
     Couplings for connecting hoses and other conduits which carry fluids have been in use for many years. One common form of such couplings, often referred to as cam and groove couplings or cam-lock couplings or cam locking quick-disconnect couplings, includes a female coupling unit on which a pair of cam arms are pivotally mounted in openings extending through the wall of the female coupling unit to the bore of the female coupling member and a male coupling unit, having a groove in an outside surface, is received in the bore of female coupling unit and is engaged by the cam arms in the groove of the male coupling unit to fix the male coupling unit in the female coupling unit. In an initial position in which the male coupling unit is inserted into the bore of the female coupling unit, the cam arms are pivoted radially outward providing clearance for the male coupling unit to be inserted. After the male coupling unit is inserted into the bore of the female coupling unit, the cam arms are pivoted inward drawing the male coupling unit into the bore of the female coupling unit to fix the male coupling unit in place while compressing a compressible sealing ring carried in a groove in the bore in the female coupling unit. To disconnect the coupling, the cam arms on the female coupling unit are pivoted outwardly to free the male coupling unit and permit removal of the male coupling unit. 
     Pressure fluctuations in the system or physically dragging the coupling can cause accidental disconnection of the coupling and a potentially hazardous spill or pressure release. Because of such potential safety hazards, many efforts have been made to improve the locking together of the male coupling unit and the female coupling unit. In some, a safety lock has been added which holds the cam arms on the female coupling unit in a closed position which is effective against pulsating pressure but ineffective against opening when the coupling is physically dragged. 
     Padlocks have been added to the couplings to protect against both unintentional and unauthorized disconnection of the coupling. Typically, the arrangements which have included a padlock have not been sufficiently effective in providing the desired protection. 
     Other efforts in the design of such couplings have involved the inclusion of parts which can be easily lost or misplaced or the addition of parts which adds cost and complexity to the couplings. Certain designs of such couplings are prone to the collection of dirt or debris making the couplings ineffective or inoperative. 
     Yet another problem with a number of prior art couplings is that the pull rings, which are carried by the cam arms, can become lodged between the cam arms and the body of the female coupling unit resulting in improper closure and connection of the male and female coupling units. In addition, these pull rings, which typically are carried loosely by the cam arms, are susceptible to being “hung up” on something as the coupling is physically dragged. 
     SUMMARY OF THE INVENTION 
     Accordingly, a safety locking coupling assembly, constructed in accordance with the present invention, includes a generally cylindrical male coupling unit and a female coupling unit which includes a generally cylindrical body, a cam arm mounted to the body of the female coupling unit, and a pull ring carried by the cam arm. The body of the female coupling unit has an inside wall defining a bore which extends axially of the body between first and second end faces of the body and within which the male coupling unit is fitted from the first end face of the body. The body also has an opening extending through the body and at least one ear projecting from an outside wall of the body adjacent the opening in the body. The cam arm is mounted to the body of the female coupling unit at the opening in body for pivotal movement relative to the body between a first pivotal locked position and a second pivotal released position. The cam arm has a cam surface projecting from within the opening in the body into the bore in the body and engaging the male coupling unit received by the bore in the body when the cam arm is in the first pivotal locked position and retracted into the first opening in the body from the bore in the body and disengaged from the male coupling unit received by the bore in the body when the cam arm is in the second pivotal released position. The cam arm also has an arm portion to which the pull ring is attached for pivotal movement of the pull ring relative to the cam arm between a first pivotal locked position and a second pivotal released position for moving the cam arm from the first pivotal locked position of the cam arm to the second pivotal released position of the cam arm. The pull ring abuts against the ear on the body of the female coupling unit upon pivotal movement of the cam arm from the first pivotal locked position of the cam arm toward the second pivotal released position of the cam arm while the pull ring is in the first pivotal locked position of the pull ring to prevent pivotal movement of the cam arm to the second pivotal released position of the cam arm and free of the ear upon pivotal movement of the pull ring from the first pivotal locked position of the pull ring to the second pivotal released position of the pull ring to permit pivotal movement of the cam arm to the second pivotal released position of the cam arm. 
     Although the embodiment of the present invention which is described below has two cam arms symmetrically disposed on the body of the female coupling unit, it will be understood that the present invention can be arranged with only one cam arm, particularly for smaller units, and with more than two cam arms, particularly for larger units. 
     Another aspect of the present invention which is described below is the manner in which the cam arm and the means by which the cam arm is mounted to the body of the female coupling unit are arranged to receive a padlock, whereby the safety locking coupling assembly is protected against tampering to a greater extent than prior art arrangements. 
     Yet a further aspect of the present invention is the configuration of the cam surface of the cam arm, whereby the cam arm is strengthened. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view, partially in section, of a safety locking coupling assembly, constructed in accordance with the present invention, prior to insertion of the male coupling unit into the female coupling unit. 
     FIG. 2 is a side view, partially in section, of the FIG. 1 safetylocking coupling assembly after insertion of the male coupling unit into the female coupling unit but prior to locking together of the male and female coupling units. 
     FIG.  3 .is a side view, partially in section, of the FIG. 1 safety locking coupling assembly at a point intermediate the locked and unlocked conditions of the coupling assembly. 
     FIG. 4 is a side view, partially in section, of the FIG. 1 safety locking coupling assembly with the male coupling unit and the female coupling unit locked together. 
     FIG. 5 is a top view of the FIG. 1 safety locking coupling assembly with the male coupling unit and the female coupling unit locked together. 
     FIG. 6 is a side view, partially in section, of the FIG. 1 safety locking coupling assembly prepared for disconnection. 
     FIGS. 7A and 7B are top and side views, respectively, of a second pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention. 
     FIGS. 8A and 8B are top and side views, respectively, of a third pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention. 
     FIGS. 9A and 9B are top and side views, respectively, of a fourth pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, a safety locking coupling assembly, constructed in accordance with the present invention, includes a generally cylindrical male coupling unit  10  and a female coupling unit  12  which includes a generally cylindrical body  14  having an inside wall  15  defining a bore which extends axially of body  14  between first and second end faces  16  and  17  of body  14 . Male coupling unit  10  is fitted within the bore of body  14  of female coupling unit  12  from first end face  16  of body  14 . The opposite end of female coupling unit  12 , for example arranged as a hose shank  18 , and the opposite end of male coupling unit  10 , for example having an internal thread  19 , are adapted for attachment to hoses or pipes. 
     The bore in body  14  of female coupling unit  12  has a circumferential groove  21  in the inside wall of the body which is spaced from first end face  18  of the body. Female coupling unit  12  further includes a compressible sealing ring  22  positioned in circumferential groove  21  which extends into the bore beyond the inside wall of body  14 . Male coupling unit  10  bears against sealing ring  22  tightly. A shoulder  25  of circumferential groove  21  in body  14  of female coupling unit  12  supports sealing ring  22  against axial movement. Male coupling unit  10  has a circumferential groove  23  in an outside surface. 
     Body  14  of female coupling unit  10  also has first and second diametrically opposed openings  24  extending through the body. Only one such opening is shown in the drawings. First and second ears  26 , shown most clearly in FIG. 5, project from an outside wall of body  14  at opposite sides of first opening  24  in the body. First and second ears  26  have a sloped, arcade surface  28 . Third and fourth ears  32 , only one of which is shown in the drawings, project from the outside wall of body  14  at opposite sides of second opening  24  in body  14  and are similar to first and second ears  26 . 
     Female coupling unit  12  also has first and second cam arms  36  and  38  mounted to body  14  at first and second openings  24  in body  14 , respectively, for pivotal movement relative to body  14  between a first pivotal locked position as shown in FIGS. 4,  5  and  6  and a second pivotal released position as shown in FIG.  1 . First cam arm  36  is mounted to first and second ears  26  by a pivot pin  40  for pivotal movement between the first and the second ears. 
     First cam arm  36  has a first cam surface  42  projecting from within first opening  24  in body  14  into the bore in body  14  and engaging male coupling unit  10  received by the bore in body  14  when first cam arm  36  is in the first pivotal locked position and retracted into first opening  24  in body  14  from bore in body  14  and disengaged from male coupling unit  10  received by the bore in body  14  when first cam arm  36  is in the second pivotal released position. First cam arm  36  also has a first arm portion  44  which, for the embodiment of the invention being described, has a first through hole  46  extending through the width thereof at a free end of first arm portion  44 . 
     Second cam arm  38  is mounted to third and fourth ears  32  by a pivot pin  48  for pivotal movement between the third and the fourth ears. Second cam arm  38  is similar to first cam arm  36  having a second cam surface, not shown but similar to first cam surface  42 , and a second arm portion  50 . The second cam surface of second cam arm  38  projects from within the second opening in body  14  of female coupling unit  12  into the bore in body  14  and engages male coupling unit  10  unit received by the bore in body  14  when second cam arm  38  is in the first pivotal locked position and is retracted into the second opening in body  14  from the bore in body  14  and disengaged from male coupling unit  10  received by the bore in body  14  when second cam arm  38  is in the second pivotal released position. For the embodiment of the invention being described, second arm portion  50  has a second through hole  52  extending through the width thereof at a free end of second arm portion  50 . 
     Female coupling unit  12  also has first and second pull rings  54  and  56  attached, respectively, to first arm portion  44  of first cam arm  36  and second arm portion  50  of second cam arm  38 . For the embodiment of the invention being described, pull rings  54  and  56  extend, respectively, through first through hole  46  in first arm portion  44  of first cam arm  36  and second through hole  52  in second arm portion  50  of second cam arm  38  for pivotal movement of the first and the second pull rings relative to the first and the second cam arms, respectively. First and second pull rings  54  and  56  can undergo pivotal movement between a first pivotal locked position and a second pivotal released position for moving first cam arm  36  and second cam arm  38 , respectively, from the first pivotal locked positions of the cam arms to the second pivotal released positions of the cam arms. Each pull ring  54  and  56  is a resilient circular multiple turn coil and each of the pull rings and each through hole  46  and  52  through which the pull rings extend are dimensioned to bias the pull rings into a position against the arm portions of the cam arms to which they are mounted in the first pivotal locked positions of the pull rings and to permit overcoming the bias and permit pivotal movement of the pull rings away from arm portions of cam arm to which they are mounted to the second pivotal released position of the pull rings when the pull rings are pulled toward the second pivotal released position of the pull rings. 
     In particular, first pull ring  54  abuts against the sloped arcade surface  28  of first and second ears  26  upon pivotal movement of first cam arm  36  from the first pivotal locked position of the first cam arm toward the second pivotal released position of the first cam arm while the first pull ring is in the first pivotal locked position of the first pull ring to prevent pivotal movement of the first cam arm to the second pivotal released position of the first cam arm. First pull ring  54  is free of first and second ears  26  upon pivotal movement of the first pull ring from the first pivotal locked position of the first pull ring to said second pivotal released position of the first pull ring to permit pivotal movement of first cam arm  36  to the second pivotal released position of the first cam arm. Second pull ring  56 , in cooperation with the sloped arcade surface  28  of third and fourth ears  32 , effects locking and movement of second cam arm  38  in the same manner as first pull ring  54 , in cooperation with first ears  26 , effects locking and movement first cam ann  36 . 
     Male coupling unit  10  preferably has a tapered end  58  and female coupling unit  12  preferably has an annular end radius  60  which together ease insertion of the male coupling unit into female coupling unit  12 . An end face  62  of male coupling unit  10  is adapted to bear tightly against sealing ring  22  in female coupling unit  12 . 
     Cam surfaces  42  of first cam arm  36  and second cam arm  38  have a relief  64  which allows insertion of male coupling unit  10  into female coupling unit  12 . Relief  64  of cam surfaces  42  is an arcade concave surface aligned with the axis of male coupling unit  10  and the axis of female coupling unit  12  when cam arms  36  and  38  are in the pivotal released positions of the cam arms as shown in FIG.  1 . The arcade nature of relief  64 , shown in FIG. 5, provides added material to the cam arms as they follow the shape of male member  10  and thereby strengthens the cams. 
     The initial phase of insertion of male coupling unit  10  into female coupling unit  12  is shown in FIG.  2 . Cam arms  36  and  38  have been moved slightly from the pivotal released positions of the cam arms, as shown in FIG. 1, toward the pivotal locked positions of the cam arms, as shown in FIGS. 3,  4  and  5 , with cam surface  42  of the cam arm arms entering groove  23  in the outside surface of male coupling unit  10 . 
     As shown most clearly in FIGS. 3,  4  and  5 , which show male coupling unit  10  inserted in female coupling unit  12 , cam surfaces  42  of cam arms  36  and  38  extend into and engage circumferential groove  23  in the outside surface of the male coupling unit when the cam arms are in the pivotal locked positions of the cam arms. As cam arms  36  and  38  are pivoted from the pivotal released positions of the cam arms to the pivotal locked positions of the cam arms, cam surfaces  42  of the cam arms further engage groove  23  in the outside surface of male coupling unit  10  and draw the male coupling unit into female coupling unit  12  and compress sealing ring  22 . At the same time, pull rings  54  and  56  ride over first and second ears  26  and third and fourth ears  32 , respectively, to snap against the associated ears. If cam arms  36  and  38  are not moved to the full pivotal locked positions of the cam arms, pull rings  54  and  56  will not ride over the ears and snap against the ears and the coupling assembly will not be safety locked. Preferably, cam arms  36  and  38  have an enlarged pad area  66  which facilitates moving the cam arms into the pivotal locked positions of the cam arms by providing a comfortable surface for the hand or heal of the hand of an operator to the exert necessary force to lock the coupling assembly. 
     Also, as shown most clearly in FIG. 5, cam arms  36  and  38  have extensions  67  and  68 , respectively, beyond through holes  46  and  52 , at the free ends of the arm portions of the cam arms. As shown most clearly in FIG. 6, extensions  67  and  68  limit pivotal movement of pull rings  54  and  56  away from the first pivotal locked positions of the pull rings to the second pivotal released positions of the pull rings to prevent undesired distortion of the pull rings when the pull rings are pulled to disconnect the coupling assembly and prevent the pull rings from passing to beneath the cam arms. 
     In addition, cam arms  36  and  38  have through holes  69  and  70 , respectively, which are aligned with aligned through holes  71  and  72 , respectively, in first and second ears  26  and third and fourth ears  32 , respectively, when the cam arms are in the pivotal locked positions of the cam arms. A padlock  74  or similar device can be fitted through the aligned through holes to prevent further accidental opening of the coupling assembly or unauthorized opening of the coupling. With cam arms  36  and  38  resting against the body of the female coupling unit as shown in FIG. 4, padlock  74  prevents cam arm  38  from being moved even if pivot pin  48  is removed. 
     To disconnect the coupling assembly, a padlock, if employed to lock the coupling assembly, first is removed. Next, the operator inserts a finger into each pull ring  54  and  56 , as shown in FIG. 6, to pull the pull rings from the pivotal locked positions of the pull rings to the pivotal released positions of the pull rings. Further pulling of the pull rings moves cam arms  36  and  38  from the pivotal locked positions of the cam arms to the pivotal released positions of the cam arms and withdraws cam surfaces  42  of the cam arms from groove  23  in the outside surface of male coupling unit  10 . 
     Preferably, surfaces  76  of each cam arm  36  and  38  opposite from cam surfaces  42  are extended and act as a barrier to projections from the environment from accessing pull rings  54  and  56  unintentionally, as best shown in FIG.  4 . 
     FIGS. 7A and 7B show a second pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention. In contrast to pull rings  54  and  56  that are resilient circular multiple turn coil rings that are axially would and extend through generally rectangular through holes  46  and  52  that are disposed perpendicular to the lengths of cam arms  36  and  38 , pull ring  100  in FIGS. 7A and 7B is a resilient circular multiple coil ring that is radially wound and extends through a generally rectangular through hole  102  that is disposed axially of a cam arm  104 . Pull ring  100  and through hole  102  are dimensioned to bias the pull ring into a position against cam arm  104  to which it is mounted in a first pivotal locked position of the pull ring and to permit overcoming the bias and permit pivotal movement of the pull ring away from the cam arm to a second pivotal released position of the pull ring when the pull ring is pulled toward the second pivotal released position of the pull ring. 
     Referring to FIGS. 8A and 8B, which are top and side views, respectively, of a third pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention, the pull ring is a resilient circular split ring  110 , the opposite ends of which extend into first and second holes  112  and  114  in opposite edges of a cam arm  116 . With holes  112  and  114  generally aligned along the length of cam arm  116  and offset perpendicular to the length of the cam arm, pull ring is biased against the cam arm into a position against the cam arm. The bias, however, can be overcome to permit pivotal movement of pull ring  110  away from cam arm  116  to a second pivotal released position of the pull ring when the pull ring is pulled toward the second pivotal released position of the pull ring. Although ring  110  is shown as a single turn split ring, it will be apparent that ring  110  can have multiple turns as represented by the dot-dash line  117  in FIG.  8 A. 
     FIGS. 9A and 9B are top and side views, respectively, of a fourth pull ring arrangement which can be used in a safety locking coupling assembly constructed in accordance with the present invention. In this arrangement, the means for urging a pull ring  120  against a cam arm  122  include a pair of springs  124  and  126 , in the form of torsion springs for the embodiment of the invention being described, extending between the cam arm and the pull ring to bias the pull ring into the position against the cam arm and permit overcoming the bias and permit pivotal movement of the pull ring away from the cam arm to the second pivotal released position of the pull ring when the pull ring is pulled toward the second pivotal released position of the pull ring. Specifically, a first end  124   a  and  126   a  of each torsion spring bears against the top of pull ring  120  and a second end  124   b  and  126   b  of each torsion spring bears against the bottom surface of cam arm  122 . 
     In contrast to the other pull rings described above which are circular in shape, pull ring  120  in FIG. 9A is generally square. Therefore, it will be understood that pull rings used in a safety locking coupling assembly, constructed in accordance with the present invention, can be other than circular in shape. Moreover, the component which serves a finger pull member need not be a complete ring. For example, the finger pull member can be L-shaped, namely a portion of pull ring  120  in FIG. 9A that has only one leg and extends only far enough to engage only one of two ears  128  and  130  to retain the finger pull member in the pivotal locked position against the cam arm or far enough to engage both ears  128  and  130  to retain the finger pull member in the pivotal locked position against the cam arm. 
     While in the foregoing there have been described preferred embodiments of the present invention, it should be understood by those skilled in the art that various modifications and changes can be made without departing from the true spirit and scope of the present invention.