Patent Application
20070237617
This invention relates to on-off loading and dumping linkages for load receiving bodies carried on a truck frame.
U.S. Pat. No. 5,108,247, issued Apr. 28, 1992, entitled “Loading Linkage” and assigned to the same assignee as the instant application, the entire disclosure of which is herein incorporated by reference, discloses a loading linkage that is multi-functional and which is intended to be mounted on the frame of a body hauling truck. The linkage provides for on loading or off loading the body to the truck frame as well as a dumping mode wherein the contents of the body may be dumped while still attached to the truck. This linkage has been in commercial use for a goodly number of years and has been very successful in the applications for which it is intended. The linkage includes a secondary link and a tilt link pivoted to the frame and which extend under and up the front of a body on the truck. A dump link is also provided and extends under the body and is pivoted to the rear of the truck frame. A first power cylinder pivotally engages the secondary link for tilting the secondary link relative to the truck frame and a second power cylinder is provided for pivoting the tilt link relative to the secondary link.
The tilt link, adjacent the dump link, has a locking tab that underlies a similar tab on the dump link in one position so as to lock all of the links for movement in unison under power from the first cylinder to effectuate a dumping mode. In addition, the tilt link may be tilted relative to the secondary link under the power of the second power cylinder to remove the tab from a position underlying the dump link to disconnect the dump link from the remaining links, thus allowing movement of the tilt and secondary links without movement of the dump link under power from the first cylinder to effectuate the on-off loading mode.
Typically, the tilt link has a hook at its end remote from the secondary link which is engageable with a grab bar mounted on the front wall of the body. The hook, when engaged with the grab bar, provides the necessary engagement with the body to provide on-off loading of the body on the truck as well as to hold the body in place during the dumping mode.
Proper operation of the linkage requires that when on loading a body, the operator should totally retract the first power cylinder before retracting the second power cylinder. If this order of operation is not followed and the second power cylinder is retracted before the first power cylinder, the tilt tab and dump tab at the interface of the tilt link and the dump link may not properly align with the tab on the tilt link coming down on top of the tab on the dump link, rather than underlying the same as is intended. The result may cause damage to the tilt or secondary links.
U.S. Pat. No. 6,749,389, issued Jun. 15, 2004, entitled “Linkage for on-off Loading and Dumping of a Dumpster on a Truck Frame” and assigned to the same assignee as the instant application, the entire disclosure of which is herein incorporated by reference, sought to avoid damaging the tilt or secondary links by use of a frangible element used to hold one of the tilt and dump tabs to one of the tilt and dump links. The frangible element in conjunction with a pivot at one of the tilt and dump tabs would allow for the avoidance of damage by breaking and letting one of the tilt and dump tabs to move out of the way of the other tab. Though the frangible element may be inexpensive to replace, it must be replaced after every improper linkage in order to properly secure the tilt and dump tab.
The present invention is directed to obviating the possibility of such damage when linkage is improperly operated without the use of a frangible element that must be replace ever time such possibility of damage is obviated.
It is the principal object of the invention to provide an improved multi-function linkage for use on a truck that may be operated in an on-off loading mode for loading or unloading a body on the truck and which may additionally be operated in a dumping mode for dumping the contents of a body while the body is secured to the truck. More specifically, it is an object of the invention to provide such a linkage wherein the possibility of damage to one or more links of the system is obviated even when the linkage is improperly operated.
In one exemplary embodiment, the invention contemplates a truck frame of a body hauling truck that provides on-off loading and dumping modes which includes a dump link pivoted to the truck frame, a secondary link pivoted to the dump link and a tilt link pivoted to the secondary link to extend under and up the front of a body. A first extendable dump motor is provided for pivoting the secondary link relative to the truck frame and a second extendable motor is provided for pivoting the tilt link relative to the secondary link. Interengageable tabs, one on the tilt link and one on the dump link, are provided to connect all of the links for movement in unison under power from the first extendable motor to effectuate the dumping mode. The invention contemplates the improvement wherein one of the tabs is pivotally and slidably mounted to one of the tilt and dump links and further includes an spring element to normally hold the one tab in proper position but allows pivotal and slidable movement when the one tab is subjected to excessive force. The spring is a further improvement in that it resets the tab for proper linkage.
A preferred embodiment contemplates the provision of a pivot pin connecting the one tab to the one of the tilt and dump links and an elongated opening defined by the tub fixed to the one tab of greater size than the pivot pin. The pivot pin extends through the elongated opening. A hook is attached to the tube opposite the one tab and pivot pin for attachment of one end of the spring. It is preferred to have a bolt for attachment of another end of the spring at the end of one of the tilt and dump links.
A further improvement contemplated by the invention is a sensor that senses excessive force on the one tab to alert that linkage must be reattempted. In the preferred embodiment the sensor secured by a nut in a bore in the one tab spaced from the tube.
Other objects and advantages will become apparent from the following specification taken in connection with the accompanying drawings.
The rear wall 28, in one mode, is defined by a pivoting door having a hinge shown schematically at 40 and a locking pin shown schematically at 42 for securing the door.
It should be understood that while a single linkage 16 is illustrated in the views of
The linkage 16 includes an L-shaped tilt link 44 pivotally connected to a secondary link 46 near one end thereof by a pivot pin 48. A dump link 50 has one end pivotally connected to the secondary link 46 oppositely of the tilt link 44 by a pivot pin 52. As illustrated in
The tilt link 44 has mutually perpendicular legs 60 and 62. The leg 60 has an outer end 64 terminating in a hook 66 which is rigidly attached to the leg 60 at a pin 68. The hook 66 is engageable with a respective one of the ends 36, 38 of the grab bar 34. The leg 62 is pivoted to the secondary link 46 by the pivot pin 48.
The secondary link 46 is an elongate rigid member having opposed ends 70 and 72. The end 72 includes the pivot 52 which joins the secondary link 46 with the dump link 50 intermediate the ends of the latter. An extendible hydraulic tilt cylinder 74 has its cylinder end 76 pivotally connected to the end 70 of the secondary link 46 and its rod end 78 pivotally connected to the outer end 64 of the tilt link 44 by the pin 68. Thus, the hydraulic cylinder 74 is operable to rotate the tilt link 44 relative to the secondary link 46 between the solid and dotted line positions shown in
The dump link 50 extends from the pivot 58 at the rear most end 80 of the frame 14 forwardly to its end 54 which is in close proximity to the end 81 of the leg 62 of the tilt link 44.
A hydraulic main power cylinder 82 has its cylinder end 84 pivotally connected by means of a pivot 86 to the frame 14 oppositely of the pivot 58. The rod end 88 of the cylinder 82 is connected at an opposite end 88 by means of pivot 90 to the secondary link 46 intermediate its ends 70 and 72.
As best shown in the enlarged view of
In one mode of operation, the linkage 16 is adapted for providing on and off loading of a typically constructed refuse receiving body 20.
Prior to entering the on-off loading mode, each of the links 44, 46 and 50 will typically be positioned as shown in solid lines in
To off load the body 20, the above process is simply reversed.
In the dumping mode of operation, the links 44, 46 and 50 are rotated in unison as a rigid structure under power from the power cylinder 82 to elevate a body 20 carried on the frame 14 to an angle sufficient to permit the discharge of material carried within the body through the end wall/door 28 under the force of gravity.
In this mode, the body 20 is elevated and tilted with the linkage 16 in the following manner. With the links 44, 46 and 50 in the configuration shown in
Once the linkage 16 is raised to an angle sufficient to allow the gravity-induced discharge of materials contained within the body 20, or prior thereto as desired, the lock pin 42 is withdrawn to permit the rotation of the end wall/door 28 about the hinge axis 40 to permit the egress of material there through. Thereafter, the cylinder 82 may be retracted to lower the linkage to the transport position shown in solid lines in
Turning now to
To avoid this problem, the structure of
Referring to
In any event, it will be appreciated that by reason of the elongated interior 116 of the tube 114, and the fact that the pivot pin 118 extends through the same, the tab 94 is pivoted to the dump link 50. In addition, because the tube 114 is rectangular, having its long dimension extending parallel to the bar 110, the dump tab 94 is also slidably mounted to the dump link 50 for movement in and out of the dump link 50 as desired.
A hook 120 is attached to the tube 114 at a location opposite the dump tab 94 and outside the interior 116 of the tube 114. A spring 122 having a first end 124 and a second end 126 is attached to the hook 120 at the spring first end 124. The spring second end 126 is attached at the end 54 of the dump link 50 such that the spring 122 is aligned to pull the hook 120 toward the end 54. This pulling also has the effect of pulling the dump tab 94 upward and outward. A spring attachment pin formed of a bolt 128 is located in the end 54 of the dump link 50 opposite the dump tab 94 for attachment of the spring second end in the preferred embodiment.
In the preferred embodiment the hook 120 and the spring ends 124 and 126 are attached by welding, but other attachments are within the scope of the invention. In an alternative embodiment, the spring second end 126 is attached directly to said end 54 and no bolt 128 is present. In another alternative embodiment, the spring first end 124 is attached directly to the tube 114 and no hook is present. It is to be understood that the length of the hook 120, however, is sufficient to transfer pull of the spring 122 to force the dump tab 94 both upward and outward sufficient to normally hold said dump tab 94 against pivotal and slidable movement.
When excess force is exerted on the dump tab 94 greater than the pulling of the spring 122, because of the use of the tube 114 and the elongated opening defined by the interior 116 of the tube 114 provided therein together with the pivot pin 118, the tab 94 may move inwardly or downwardly, or both, within the dump link 50. As can be appreciated by
After an improper linkage, the spring 122 will pull the dump tab 94 upward and outward to reset the dump tab 94. At this point, the tilt tab 106 will underlie the dump tab 94 and the entire linkage, whether employed for on-off loading or for dumping, will operate in the manner previously described. Thus, damage that could be expensive or time consuming to repair is easily avoided through the use of the spring 122.
At a location spaced from the tube 114, and thus from the pivot pin 118, a bore 130 (
While the invention has been described in terms of pivotally and slidably mounting the tab 94 on the dump link 50, it will be appreciated that the same sort of mechanism could be utilized in mounting the tilt tab 106 to the tilt link 44 provided spatial difficulties do not arise. In the embodiment illustrated, the pivot 48 between the tilt link 44 and the secondary link 46 may hinder such placement but those skilled in the art will readily appreciate that any spatial constraints provided by the presence of the pivot 48 can be avoided simply by repositioning the pivot 48.
