Abstract:
Slidably mounted within the cylinder  108  of the accumulator  46  is a piston  48 . A spring  50  is positioned behind the piston  48 , which biases the piston  48  toward port  56 . The portion of the cylinder  108  occupied by spring  50  is vented to the atmosphere by breather  52 , which allows air to pass in and out of cylinder  108 . As a result of the spring  50  acting on the piston  48 , fluid is collected, stored, and released from the cylinder  108  under pressure. It should be understood that the accumulator could collect, store and release fluid under pressure using energy storage devices other than spring  50 . For example, the accumulator  46  could be gas.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a latching device and method for a refuse cart tipper. More particularly, the present invention provides a new latching device and method that offers fail-safe precision timing and movement of the latch motion relative to the tipper lift motion so as to accommodate a broad range of refuse carts, account for obstructions in latch movement, and be readily adaptable to many different types of refuse cart tippers. 
     BACKGROUND OF THE INVENTION 
     Refuse cart tippers (“tippers”) are well known in the prior art. These tippers use mechanical linkage to rotate or slide a latch for hooking a bar on the refuse cart so that the cart does not fall off the tipper. Using mechanical linkage to operate latch motion has many disadvantages. For example, mechanical linkage systems will break or bend if an obstruction is in the latch path. Therefore, there is a need for a refuse tipper latching device and method that protects operational members and components of the latch system from damage. 
     Refuse carts differ in shape and size. For example, the position of the lower bar relative to the upper lip may vary between refuse carts. Therefore, the system for driving the hook or slider latch must be adaptable and flexible to account for size variations in the refuse cart. Often with mechanical latches that use linkage bars to rotate or slide a latch, the range of motion and timing of the latch is difficult to control and adjust. For example, if the lower bar on the refuse cart is outside the range of motion configured into the mechanical linkage of the latch, the latch will either fail to hook the lower bar of the refuse cart resulting in the refuse cart coming unhooked from the tipper or the latch will bend or break the lower bar. Therefore, there is a need for a refuse tipper latching device and method that accounts for changes in the position of the lower bar by providing adaptable motion and timing of the latch relative to the position or motion of the tipper and/or position of the lower bar and/or upper lip to prevent damage to the refuse cart. 
     Oftentimes with refuse tippers, the mechanical linkage for operating the latch is a restrictive design feature which means that the refuse tipper may only be used for certain operating heights, size and shaped refuse carts, and ranges of movement, rotational or otherwise. Therefore, there is need for a refuse tipper latching device and method that can be adapted and incorporated into many types of refuse tippers regardless of the range of operating motion, heights, and/or configurations. 
     BRIEF SUMMARY OF THE INVENTION 
     Therefore, it is a primary object, feature, or advantage of the present invention to improve over the state of the art. 
     A further object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein a master cylinder is in fluid communication with slave cylinder by a flexible hose to operate a latch for keeping a refuse cart on a refuse tipper. 
     Yet another object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein the master cylinder has a rod, and a roller attached to the rod adapted to follow a cam plate as the tipper moves. 
     A further object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein fluid is displaced from the master cylinder into a slave cylinder that is attached to a latch for keeping a refuse cart on the refuse tipper. 
     Yet another object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein the slave cylinder is spring-returned so as to force fluid back into the master cylinder and retract the latch. 
     Still another object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein the master cylinder is in fluid communication through a counterbalance valve with an accumulator so that if fluid pressure exceeds the pressure set point of the counterbalance valve, due to some obstruction, the counterbalance valve opens to allow fluid into the accumulator. 
     Yet another object, feature, or advantage of the present invention is to provide a refuse tipper latching device and method wherein fluid within the accumulator is used collected, stored and released under pressure. 
     One or more of these and/or other objects, features, or advantages of the present invention will become apparent from the specification and claims that follow. 
     According to one aspect of the present invention, a latching device for holding a refuse cart to a refuse tipper is disclosed. The latching device uses a master cylinder in fluid communication with a slave cylinder. The slave cylinder is adapted to operate a latch to thereby retain the refuse cart on the refuse tipper. In the preferred form, the master cylinder has a cylinder adapted to slidably receive a rod having a first end for movement within the cylinder and a roller operably attached to a second opposite end of the rod for movement without the cylinder. The roller is biased against a cam plate by a spring acting within the cylinder against the first end of the rod. The roller travels along the cam plate when moving the refuse tipper. The cam plate is adapted to time movement of the latch to thereby secure the refuse cart to the refuse tipper upon travel of the roller along the cam plate, which moves the rod to force fluid through a hose into the slave cylinder. The master cylinder has an accumulator with a piston slidably mounted and spring biased therein to receive, store and release fluid under pressure. The master cylinder also has a counterbalance value adapted to control movement of fluid between the accumulator and the cylinder so that fluid is forced through the counterbalance valve into the accumulator if the latch is obstructed, which prevents damage to the latching device and/or the refuse cart. The slave cylinder has a cylinder adapted to slidably receive a rod having a first end attached to and moved by a piston slidably mounted within the cylinder and a rod end mount operably attached to a second opposite end of the rod for movement without the cylinder. The latch is operably attached to the rod end mount so that fluid forced from the master cylinder extends the latch into a latching position to hold a lower bar on the refuse cart. 
     A new method for latching a refuse cart to a refuse tipper is also disclosed. The method includes providing a latching device with a master cylinder in fluid communication with a slave cylinder. The slave cylinder is adapted to operate a latch for keeping the refuse cart on the refuse tipper. The method also includes forcing fluid from the master cylinder into the slave cylinder when moving the refuse tipper and extending the latch with the slave cylinder to keep the refuse cart on the refuse tipper. In the preferred form, the method includes providing a rod for forcing fluid out of the master cylinder having a roller spring biased against a cam plate shaped to drive the roller relative to the position of the refuse tipper, following the cam plate with the roller when moving the refuse tipper to thereby extend or retract the latch, retracting the latch for releasing the refuse cart from the refuse tipper by forcing fluid from the slave cylinder into the master cylinder, and preventing damage to the refuse cart and/or the latching device by forcing fluid through a counterbalance valve into an accumulator when fluid pressure exceeds settings for the counterbalance valve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the specification concludes with the claims particularly pointing out and distinctly claiming the invention, it is believed that the present invention will be better understood from the following description taken in conjunction with the accompanied drawings in which: 
         FIG. 1  is an isometric view of the refuse tipper and latching device according to an exemplary embodiment of the present invention. 
         FIG. 2  is a front view of the refuse tipper and latching device according to an exemplary embodiment of the present invention. 
         FIG. 3  is a back view of the refuse tipper and latching device according to an exemplary embodiment of the present invention. 
         FIG. 4  is a cut-away view of the refuse tipper and latching device in a stowed position according to an exemplary embodiment of the present invention. 
         FIG. 5A  is a side cut-away view of the refuse tipper and latching device in the engagement position according to an exemplary embodiment of the present invention. 
         FIG. 5B  is a side cut-away view of the refuse tipper and latching device with the refuse cart in a lifted position according to an exemplary embodiment of the present invention. 
         FIG. 5C  is a side cut-away view of the refuse tipper and latching device with the refuse cart in a dump position according to an exemplary embodiment of the present invention. 
         FIG. 6A  is a sectional view of the refuse tipper and latching device taken along line  6 A- 6 A in  FIG. 5A . 
         FIG. 6B  is a sectional view of the refuse tipper and latching device taken along line  6 B- 6 B in  FIG. 5B . 
         FIG. 6C  is a sectional view of the refuse tipper and latching device taken along line  6 C- 6 C in  FIG. 5C . 
         FIG. 7A  is an isolation view of the latching device according to an exemplary embodiment of the present invention. 
         FIG. 7B  is an isolation view of the latching device with slave cylinder extended according to an exemplary embodiment of the present invention. 
         FIG. 7C  is a cut-away view of the slave cylinder according to an exemplary embodiment of the present invention. 
         FIG. 8A  is an isometric view of the master cylinder according to an exemplary embodiment of the present invention. 
         FIG. 8B  is a sectional view of the master cylinder taking along line  8 B- 8 B in  FIG. 8A . 
         FIG. 8C  is a hydraulic schematic of the latching device according to an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention includes a number of aspects, all of which have broad and far-reaching application. One aspect of the present invention relates to providing a refuse tipper latching device and method wherein a master cylinder is in fluid communication with a slave cylinder by a flexible hose to operate a latch for keeping a refuse cart on a refuse tipper. Another aspect of the present invention is to provide a refuse tipper latching device and method wherein the master cylinder has a rod, and a roller attached to the rod adapted to follow a cam plate as the tipper moves. Another aspect of the present invention relates to the use of a refuse tipper latching device and method wherein fluid is displaced from the master cylinder into a slave cylinder that is attached to a latch for keeping the refuse cart on the refuse tipper. Still another aspect of the present invention is to provide a refuse tipper latching device and method wherein the slave cylinder is spring-returned so as to force fluid back into the master cylinder and retract the latch. Although specific embodiments are described herein, the present invention is not to be limited to these specific embodiments. The present invention contemplates numerous other options in the design and use of the refuse tipper latching device and method. 
       FIG. 1  is an isometric view of the refuse tipper latching device according to an exemplary embodiment of the present invention.  FIG. 1  shows the latching device  22  mounted one style or type of a refuse tipper  10 . It should be understood that due to the flexibility of the latching device  22 , using the combination of master cylinder  30  and slave cylinder  64  to operate, could be configured to various styles and types of refuse tippers. For example, it could be configured to operate on a four-bar refuse tipper and/or any other style of refuse tipper known in the art, whether for stationary or mobile applications. 
     The refuse tipper  10  has a mounting plate  12 , as best shown in  FIG. 3 , for securing the refuse tipper  10  to some transportation unit, such as a garbage truck, or a stationary unit, such as a refuse compactor or dumpster. Rotary actuator  14  is secured to the mounting plate  12 . A torque arm  16  is rotatably mounted on both sides of the rotary actuator  14  to thereby rotate the face plate  18  about the rotary actuator  14 . Mounted between the torque arm  16  and the face plate  18  is a cam plate  24  having a roller path  26  around its outer circumference. It can be appreciated that the cam plate  24  need not be necessarily mounted between the torque arm and face plate, but may be mounted elsewhere relative to the rotary actuator  14 . Also, saddle  20  is mounted to the face plate  18 . The saddle  20  is for gripping the upper lip  100  of a refuse cart  98  as best shown in  FIGS. 5A-5C  and  6 A- 6 C. Secured to the back side of the face plate  18  is the latch device  22 . The latch device  22  is secured to the face plate  18  by way of latch cylinder mounts  82 . A slave cylinder  64  is attached to latch cylinder mounts  82  by way of mounting block  80 . The slave cylinder  64  is in fluid communication with hose assembly  60 . The slave cylinder  64  has a bleeder screw  74  for bleeding fluid from the slave cylinder  64 . Mounted between latch cylinder mounts  82  is latch  84 . A stop block  94  is attached to the face plate  18  on each side of the latch  84  as best illustrated in  FIG. 2 . The stop block  94  is used in combination with the latch  84  to keep the refuse cart  98  on the refuse tipper  10  as shown in  FIG. 6C . 
       FIGS. 2 and 3  illustrate how the master cylinder  30  and slave cylinder  64  are positioned relative to each other on the refuse tipper  10 . The master cylinder  30  is secured to the face plate  18  between the face plate  18  and torque arm  16 . Alternatively, the master cylinder  30  could be fixed to a torque arm  16  or any member that might be rotated relative to the rotary actuator  14  and/or some other component. For example, if hydraulic cylinders (not shown) were used to lift the refuse tipper  10 , the master cylinder  30  could be attached to a member moved by the hydraulic cylinders to force fluid from the master cylinder  30 . The master cylinder  30  has a rod  34  with a roller  38  attached at one end of the rod  34  for rolling along the roller path  26  of the cam plate  24 . The master cylinder  30  is fluid communication with the slave cylinder  64  by way of hose assembly  60 , which permits the present invention to be configured to fit endless styles and types of refuse tippers having different space, movement and operating requirements and limitations. For example, the master cylinder  30  may be positioned apart from the slave cylinder  64  on the refuse tipper  10  or wherever space permits. 
       FIG. 4  shows a cut-away side view of one style or type of a refuse tipper  10  in the stowed position  86 . In this view, the side of the face plate  18  shown in  FIG. 1  is cut-away to expose and illustrate the different components used to operate the latching device  22 . The stowed position  86  refers to the position of the refuse tipper  10  relative to the mounting plate  12 . Thus, the use of the term stowed position  86  is only for the purposes of illustration. For instance, depending on the permittable rotation of the refuse tipper  10 , the stowed position could be the positioned illustrated by the refuse tipper in  FIG. 4  or in  FIG. 5A . 
     In  FIG. 4 , the cam plate  24  is exposed to view. As shown, the cam plate  24  has an aperture  28  for purposes of accommodating the rotary actuator  14 . A roller path  26  defines the outer periphery of the cam plate  24 . Designed to follow along the outer periphery or roller path  26  of the cam plate  24  is roller  38 . Roller  38  is secured to the rod  34  by way of rod end mount  36 . Roller  38  rolls along the roller path  26  of the cam plate  24  when the rotary actuator  14  rotates torque arm  16 . FIGS.  4  and  6 A- 6 C illustrate how the roller  38  follows and rolls along the roller path  26  of the cam plate  24  when the rotary actuator  14  rotates torque arm  16  from the stowed position  86  to the dump position  92 . The master cylinder  30  is attached to face plate  18  (cut away portion) by way of mounting holes  58  so the master cylinder moves with the torque arm. Similarly, the master cylinder  30  may be attached to the torque arm  16  or any other member that might be rotated relative to the rotary actuator  14  and/or some other component as previously discussed. The master cylinder  30  may be attached to either by way of a bolt, screw or rivet. The master cylinder  30  has a check valve  96  where fluid may be introduced into the master cylinder  30 . This fluid may be forced out of the master cylinder  30  by compressing rod  34  so that fluid passes through fitting  62 , hose assembly  60  and into slave cylinder  64  to operate the latching device  22  to thereby move latch  84 . 
     As can be appreciated in  FIGS. 4 ,  5 A- 5 C and  6 A- 6 C, the cam plate  24  may be shaped to create any desired roller path  26 . For example, the roller path  26  or the outer periphery of the cam plate  24  may be a farther distance from the center of the cam plate  24  or a shorter distance from the center of the cam plate  24  at different positions along the roller path  26  depending upon the desired shape of the cam plate  24 . 
     The use of the cam plate  24  to operate the latching device  22  is best illustrated in  FIGS. 5A-5C  and  6 A- 6 C.  FIGS. 5A-5C  show the latching device  22  on one style of a refuse tipper  10  for dumping a refuse cart  98 . For example, in  FIG. 5A , the refuse tipper  10  and latching device  22  are in the engagement position  88 . In this position, the refuse tipper engages the upper lip  100  of the refuse cart  98 . If the refuse tipper  10  is in the stowed position  86 , as illustrated in  FIG. 4 , the rotary actuator  14  has rotated the refuse tipper  10  to the engagement position  88  as shown in  FIG. 5A . As discussed previously, depending on the type and style of refuse tipper  10 , the position of the refuse tipper  10  illustrated in  FIG. 5A  may represent the engagement position  88  and stowed position  86  (shown in  FIG. 4 ). 
     Comparing  FIG. 4  and  FIG. 6A , one can see that roller  38  has traveled across the roller path  26 , but the latch  84  position remains unchanged. The latch  84  remains in the same position from the stowed position  86  ( FIG. 4 ) to the engagement position  88  ( FIG. 6A ) because the distance of the roller path  26  from the center of the cam plate  24  is unchanged. Thus, as the roller  38  travels along the roller path  26  of the cam plate  24 , the rod  34  position remains unchanged with respect to the master cylinder  30  so there is no transfer of fluid from the master cylinder  30  into the slave cylinder  64  to operate the latch  84  ( FIG. 6A ). 
       FIGS. 5B and 5C  show the refuse cart  98  in the lift position  90  and dump position  92 , respectively.  FIGS. 6B and 6C  show sectional views for both the lift position  90  shown in  FIG. 5B  and the dump position  92  shown in  FIG. 5C . In the lift position  90 , as illustrated in  FIG. 6B , the shape of the cam plate  24  begins to change; a larger distance separates the roller path  26  from the center of the cam plate  24 . Because the master cylinder rotates by way of the rotary actuator  14  at a fixed distance from the center of the cam plate  24 , the roller path  26  forces the rod  34  into the master cylinder  30 —causes fluid to be forced into the slave cylinder  64  which operates the latching device  22 —to move the latch  84  into a position over the lower bar  102  of the refuse cart  98 . Continuing the rotation of the refuse tipper  10  from the lift position  90  shown in  FIG. 6B  to the dump position  92  shown in  FIG. 6C , the rod  34  is driven farther into the master cylinder  30  which forces fluid from the master cylinder  30  into the slave cylinder  64  so the latch  84  moves into the latching position  106  as shown in  FIG. 6C . Once the latch  84  is in the latching position  106 , the cam plate  24  remains unchanged in shape and thereby retains the position of the latch  84  as the roller  38  travels along the remaining roller path  26  of the cam plate  24 . 
       FIGS. 7A and 7B  illustrate how the latching device  22  moves upon actuation of the slave cylinder  64 . The latching device  22  is attached to the slave cylinder  64  by way of rod end mount  78 . The rod end mount  78  is attached to the rod  72  of the slave cylinder  64 . Thus, fluid from the master cylinder  30  forces the rod  72  with rod end mount  78  attached to the latching device  22  outward away from the slave cylinder  64 . The latching device  22  is rotatably mounted to latch cylinder mounts  82  so that the latching device  22  pivots. The slave cylinder  64  is mounted to the latch cylinder mounts  82  by way of the mounting block  80 , as best illustrated in  FIGS. 1 and 7B . The latch need not necessarily be rotatably mounted. For example, the latch could be designed to be a sliding latch where rollers on the latch are adapted to follow a channel for moving the latch between some extended (latching position) and some retracted position (stowed position). 
     A cutaway view of the slave cylinder  64  is shown in  FIG. 7C . The slave cylinder has a cylinder body  66  for housing rod  72 , guide  68 , spring  104 , and head gland  70 . Rod  72  is slidably mounted within the slave cylinder  64  and positioned through head gland  70 . On one end of the rod  72  is attached rod end mount  78 . On the other end of rod  72  is guide  68 . Spaced between the head gland  70  and guide  68  is spring  104 . In operation, fluid is introduced into the slave cylinder  64  through fitting  62  in port  76 . Fluid introduced into slave cylinder  64  through port  76  displaces rod  72 , as shown in  FIGS. 7A and 7B . Because the rod  72  is force displaced by the fluid, port  76  could be positioned anywhere on the master cylinder  64 . Spring  104  biases the guide  68  toward the port  76  side of the cylinder body  66 . As rod  72  is drawn back into the cylinder body  66 , fluid is displaced and forced from the slave Movement of the guide  68  toward the port  76  side draws the rod  72  back into the cylinder body  66 , which retracts the latch  84  to the position shown in  FIG. 7A . For example, when the refuse tipper  10  moves from the dumping position  92  back to the engagement  88  or stowed position  86 , shown in  FIGS. 4 ,  5 A- 5 C and  6 A- 6 C, the roller  38  is continually biased against the roller path  26  on the cam plate  24 , which is accomplished by both the spring  42  within the cylinder  40  of the master cylinder  30  (shown in  FIG. 8B ) and fluid being displaced from the slave cylinder  64  as a result of the spring  104  acting on the guide  68  (shown in  FIG. 7C ). 
     In the preferred embodiment, the slave cylinder  64  is spring returned using spring  104  positioned within the cylinder body  66 . Alternatively, spring  104  could be a single spring or multiple springs positioned on the outside of the slave cylinder  64  being adapted to retract the latch  84  (in  FIGS. 7A &amp; 7B ). 
     The master cylinder  30  is shown in  FIG. 8A . The master cylinder has a cylinder body  32 , ports  56  and mounting holes  58 . The master cylinder  30  also has a rod  34  slidably mounted that moves in position relative to the cylinder body  32 . On one end of the rod  34  is attached rod end mount  36 . The rod end mount  36  is a carriage for roller  38 . Port  56  near rod  34  has a breather  52 . 
       FIG. 8B  shows a cross-sectional view of the master cylinder  30  taken along line  8 B- 8 B in  FIG. 8A . As shown in  FIG. 8B , the rod  34  is slidably mounted with cylinder  40 . The rod  34  is spring-biased with spring  42  to urge the rod  34  out of the cylinder  40 . Fluid is forced out of cylinder  40  through port  56  (in fluid communication with the cylinder  40 ) when rod  34  is pushed into the cylinder. A plug, such as plug  54 , is used to close unused ports on the master cylinder  30 . 
     Positioned within the cylinder body  32  of the master cylinder  30  is an accumulator  46 . Although the accumulator  46  is shown and described as being a single component with the master cylinder  30 , it is understood that the accumulator  46  could be a separate component. For example, the accumulator  46  and master cylinder  40  could be separate components positioned apart on the refuse tipper  10 , but fluidly connected with a fluid line, such as hose assembly  60 . 
     A latching device is beneficial for holding a refuse cart to a refuse tipper. The latching device has a master cylinder in fluid communication with a slave cylinder. The slave cylinder is adapted to operate a latch to move from open to closed to thereby retain the refuse cart on the refuse tipper. 
     Positioned between the cylinder  40  and accumulator  46  is a counterbalance valve. The counterbalance valve  44  performs the same function of both a check valve and relief valve. Thus, the counterbalance valve  44  could be replaced with a separate check valve in combination with a separate relief valve. The check valve permits free flow of fluid from the accumulator  46  to the master cylinder  30  and the relief valve permits controlled flow (based upon pressure of the fluid) from the master cylinder  30  to the accumulator  46 . In the preferred embodiment, the counterbalance valve  44  has a pressure relief setting for controlling the pressure at which fluid is allowed to pass from the cylinder  40  through the counterbalance valve  44  and into the accumulator  46 . Thus, if fluid pressure in the master cylinder  30  exceeds the set point of the counterbalance valve  44 , the valve opens to permit fluid to flow into the accumulator  46  to relieve the excess pressure. The counterbalance valve  44  helps protect the slave cylinder  64  and master cylinder  30  from being damaged by high fluid pressures. The counterbalance valve  44  also prevents the latching device  22 , as shown in  FIGS. 7A and 7B , from damaging the refuse cart  98  and/or the lower bar  102  (shown in  FIGS. 5A-5C  and  6 A- 6 C). For instance, the position of the lower bar  102  relative to the upper lip  100  may vary between different refuse carts. If the lower bar  102  is closer to the upper lip  100  or outside the configured range of motion for the latch  84 , the latch  84  would still try to move to the latching position (shown in  FIG. 6C ), but at the risk of either bending or breaking the lower bar  102  or causing damage to the master cylinder  30 , slave cylinder  64 , or any other component that might be exposed to large fluid pressures as a result of the latch  84  being obstructed in its movement. With the present invention, the counterbalance valve  44  allows fluid, under pressure exceeding the set point of the counterbalance valve  44  because of an obstruction in the movement of the latch  84 , slave cylinder  64 , or master cylinder  30 , to be accumulated within the accumulator  46 . When the obstruction is removed, the accumulator  46  reintroduces the fluid back into the cylinder  40  of the master cylinder  30  to recharge the master cylinder  30  with the fluid that was displaced due to the obstruction and resulting high fluid pressure. Thus, the counterbalance valve  44  will compensate for any fluid pressure spikes to prevent damage to the lower bar  102  of the refuse cart  98  and/or the various working components of the latching device  22 , master cylinder  30  and slave cylinder  64 . 
     The hydraulic schematic in  FIG. 8C  best illustrates how the counterbalance  44  regulates the pressure between the slave cylinder  64  and the master cylinder  30 .  FIG. 8C  shows the master cylinder  30  in fluid communication with the slave cylinder  64  by way of hose assembly  60  or fluid line. In  FIG. 8C , the dashed box represents the master cylinder  30  shown in  FIG. 8B . The master cylinder  30 , counterbalance valve  44  and accumulator  46  are shown as a single component in the schematic, however, as previously discussed, these components could be separate components.  FIG. 8C  also shows slave cylinder  64  having a spring  104  for purposes addressed previously. For fluid to flow through the hose assembly  60 , counterbalance  44  and into the accumulator  46 , the pressure of the fluid must meet or exceed the set point of the counterbalance valve  44 . For example, if the movement of latch  84  (shown in  FIGS. 6A-6C ) is obstructed in any way, the resulting increase in fluid pressure causes the counterbalance valve  44  to open so fluid can pass through the counterbalance valve  44  into the accumulator  46 . Once fluid is introduced into the accumulator  46 , it is stored in the accumulator under pressure as a result of spring  50 . The accumulator  46  recharges the slave cylinder  64  and/or master cylinder  30  by pushing fluid back through hose assembly  60  into slave cylinder  64  and/or master cylinder  30 . 
     The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. For example, the present invention describes the latch device  22  for gripping the lower bar  102  of a refuse cart  98 , however, it should be understood from the present invention that the latching device  22  could also be configured for gripping the upper lip  100  on a refuse cart  98 . From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.