This application relates generally to refuse collection and disposal equipment. More specifically, this application relates to relates to trunnion bar restraining systems for rear loading refuse trucks.
Community refuse or garbage collection and disposal is a key component of modern civilization. Each day in the United States, tens of thousands of garbage trucks move to all corners of the country, with a garbage truck visiting virtually every home and business at least once each week. Over time, garbage collection has evolved to employ better technologies to provide efficiency and safety during the garbage collection and disposal.
In 1938 the first rear loading packing garbage truck was developed. In 1958 Garwood came out with the first hydraulic “kick bar” container hoist on the LP-500 for lifting up to 1.5 cubic yard containers. By the early 1960's rear loaders were using cable winches to empty large dumpsters into the rear loader. These containers utilized a trunnion bar across the front top of the container. The trunnion bar sticks out past each edge of the container. Each side of the trunnion bar engages a holding piece on the rear loader. The winch cable pulls the container up and the forces are such that the trunnion bar is held in the holding piece. In the early days of dumping containers with a winch, many trucks had no locking bars to secure the trunnion bar in the holding piece. Trucks that used a “kick bar” or “roll bar” to raise the container, on the other hand, had trunnion locking bars and latches as they were necessary to dump a container with the kick bar. Later as a safety measure all rear loaders came with trunnion locking bars and latches even if they only utilized the winch for dumping.
If the trunnion locking bars 2 and latches are not secured and the packing panels in hopper 20 are cycled while the container is still elevated, enough force in the right direction can be generated by the packing panels 21 and refuse to push the trunnion bar away from the holding piece past the hopper lip 25, dislodging it from holding piece the back of the truck. If both sides of the trunnion bar are dislodged at the same time the container falls to the ground. If the passenger's side trunnion bar is dislodged, that side falls to the ground usually dislodging the driver's side of the trunnion bar. The momentum gained during that fall can cause the container to pivot around the end of the trunnion bar on the ground and swing on the cable around to the side of the truck were the operator is standing, potentially injuring and/or killing the operator or anyone standing nearby; this is known as “container swing.”
Several operators have been injured and killed in the past by container swing. Container swing is such a well known, catastrophic problem that OSHA issued a bulletin specific to this problem that recommends the container be lowered to the ground before actuating the packing panels 21. Although this would eliminate the container swing, it is time consuming, and therefore many users will not do it. There are also times when the operator either forgets or for some other reason does not secure the locking bars and latches around the trunnion bar. Without the locking bars 2 latched in place, the trunnion bar can be pushed out in response to operation of the packing panels 21.
There are several mechanisms that have been used to address container swing on rear loading garbage trucks. The first are the trunnion locking bars 2 and latches that now come standard on all rear loading refuse trucks with commercial container dumping capability. These are designed to hold a trunnion bar from being pushed out of the holding piece in place while the container is elevated either by winch cable or buy a kick bar. There are two locking bars 2 and two latches, one of each on either side of the hopper 20. The locking bar pivots near the hopper sill of the truck and the latch holds the locking bar in the raised position to lock it behind the trunnion bar. Despite these devices, garbage trucks using holding piece 1 and locking bars 2 have still experienced container swing resulting in serious injuries and death. The difficulty is that it takes time and effort to secure the locking bars and latches on both sides of the truck and because it is not necessary to secure the locking bars in order to dump a container with a winch cable, the locking bars and latches may be left undone. Other devices such as the applicant's U.S. Pat. No. 5,006,030 have attempted to use hydraulic power to latch the trunnion bar to the truck. These devices are expensive and heavy and reduce the payload of the garbage truck considerably.
In normal operation the combination of the weight of the container and the force of the winch cable to raise the container, forces the trunnion bar into the trunnion pocket at the bottom of the holding piece. Since a typical container may hold significantly more refuse than the hopper of the garbage truck can hold, it is not uncommon for the operator to cycle the packer panels while the container is raised up in the air. If the packer panels are cycled while the container is raised, it is possible for them or garbage they are pushing, to push on the container trunnion or the container itself. If the force is sufficient, it may push the trunnion out of the pocket at the bottom of the holding piece, disengaging it from the truck. The direction of the force on the trunnion or container is limited by the direction of movement of the packer panels when they are opening. Although it will vary depending on the construction of the particular packer panels and the material being pushed by them, the maximum angle that can be exerted on the trunnion bar or container is generally less than 40° above horizontal to the rear. Yet, if the trunnion bar can slide forward of the hopper lip in the holding piece when the container is being raised, when the container is lowered, the container rotates around the hopper lip raising the trunnion bar in an almost vertical direction. The present invention makes use of this difference in direction of the forces to keep the trunnion bar from being pushed out of the container retention system when subject to the forces that the packer panels can exert, yet allows the trunnion bar to come out when the container is lowered.
This application discloses trunnion bar retention systems, the systems may include a pair of holding pieces configured to be coupled to a garbage truck; and a stop formed in each of the holding pieces configured to substantially prevent a trunnion bar from exiting the retention system when a container is dumped into the garbage truck and pushed rearward in response to the action of the packer panels, wherein the stop may be fixedly attached to, or integrally formed with the holding piece. In some embodiments, the stop and the holding piece form a trunnion pocket. The stop may include a portion that is at a steep enough angle that the trunnion bar cannot be pushed past it when considering the weight of the container, the coefficient of friction of the trunnion on the holding piece, the force exerted on the container by the packer panels and the force of the cable on the container. This will be discussed in detail later. The system may further include a locking bar pivotably coupled to each of the pair of holding pieces or elsewhere to the rear of the garbage truck, and a latch coupled to each of the pair of holding pieces, the latches being configured to selectively secure the locking bars to the holding pieces.
In some embodiments, trunnion bar retention systems may be used by providing a rear-loading garbage truck having a trunnion bar retention system; backing the garbage truck to a refuse container having a trunnion bar; lifting a portion of the refuse container with a cable or other means such that trunnion bar contacts a portion of the trunion bar retention system such that the container rotates about the hopper lip; sliding the trunnion bar into a trunnion pocket at which point the container will rotate about the trunnion bar; the trunnion pocket formed in the trunnion bar retention system with a holding piece and a stop, the stop being formed such that the trunnion bar cannot slide out of the trunnion bar retention system when the trunnion bar is primarily bearing the weight of the refuse container and is being pushed rearward in response to the action of the packer panels; and lowering the refuse container until a portion of the refuse container other than the trunnion bar pivots against a portion of the garbage truck lifting the trunnion bar over the stop and out of the trunnion pocket.
In some embodiments, trunnion bar retension systems may be used by providing a rear loading garbage truck a trunnion bar retention system; backing the garbage truck to a refuse container having a trunnion bar; latching the trunnion bar into the trunnion bar retension system with locking bars and latches; rotating the container with a kick bar such that as the container is raised, the trunnion slides down into a trunnion pocket at which point the container will rotate about the trunnion bar; the trunnion pocket formed in the trunnion bar retention system with a holding piece and a stop, the stop being formed such that the trunnion bar cannot slide out of the trunnion bar retention system when the trunnion bar is primarily bearing the weight of the refuse container and is being pushed rearward in response to the action of the packer panels; and lowering the refuse container until a portion of the refuse container other than the trunnion bar pivots against a portion of the garbage truck lifting the trunnion bar over the stop and out of the trunnion pocket.
The following description can be better understood in light of the Figures, in which:
The Figures illustrate specific aspects of exemplary trunnion bar restraining systems and methods for making and using such devices as described below. Together with the following description, the Figures demonstrate and explain the principles of the structures, methods, and principles described herein. In the drawings, the thickness and size of components may be exaggerated or otherwise modified for clarity. The same reference numerals in different drawings represent the same element, and thus their descriptions will not be repeated. Furthermore, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the described devices. Moreover, the Figures may show simplified or partial views, and the dimensions of elements in the Figures may be exaggerated or otherwise not in proportion for clarity.
The following description supplies specific details in order to provide a thorough understanding. Nevertheless, the skilled artisan would understand that the described trunnion bar restraining systems and methods of restraining container trunnion bars can be implemented and used without employing these specific details. Indeed, the trunnion bar restraining systems and associated methods can be placed into practice by modifying the illustrated devices and methods and can be used in conjunction with any other apparatus and techniques conventionally used in the industry.
In addition, as the terms on, attached to, or coupled to are used below, for clarity of describing function, one object (e.g., a material, a layer, a substrate, etc.) can be on, attached to, or coupled to another object regardless of whether the one object is directly on, attached, or coupled to the other object or there are one or more intervening objects between the one object and the other object. Also, directions (e.g., above, below, top, bottom, side, up, down, under, over, upper, lower, forward, rearward, sideward, horizontal, vertical, “x,” “y,” “z,” etc.), if provided, are relative and provided solely by way of example and for ease of illustration and discussion and not by way of limitation. In addition, where reference is made to a list of elements (e.g., elements a, b, c), such reference is intended to include any one of the listed elements by itself, any combination of less than all of the listed elements, and/or a combination of all of the listed elements.
Some embodiments of the exemplary trunnion bar restraining systems and methods of making and using these systems are described in detail below and illustrated in the Figures.
Similarly, holding piece 101 may be placed against other portions of garbage truck 10, or other elements to keep it stationary and fixed to garbage truck 10, such as locking bar mount 4, which may be also attached to garbage truck 10 by welding, bolting, or any other attachment process, or by placement against other components of garbage truck 10, such as hopper lip 25, and/or bolted to garbage truck 10. Locking bar bolt 7 may pivotably couple locking bar mount 4 to locking bar 2, such that locking bar 2 may rotate about locking bar bolt 7.
Holding piece 101 may also include stop 108 and trunnion pocket 109. Holding piece 101 may be formed generally to provide an open slot ending with trunnion pocket 109 to receive trunnion bar 41 (shown in subsequent Figures). Stop 108 may be a portion of holding piece 101 which resists exit of trunnion bar 41 from trunnion pocket 109 when pushed along a bottom of trunnion pocket 109 in response to the force 19 of the packer panels, requiring instead that trunnion bar 41 be lifted upwardly to avoid stop 108 to be withdrawn from trunnion pocket 109.
As shown in
Referring now to
The driver may then secure locking bars 2 around trunnion bar 41 with latch 3. Cable 37 may then be retracted with a winch, raising the far end of the container off of the ground, as shown in
During the lifting process, once trunnion bar 41 contacts portions of holding piece 101, container 40 may rotate about the fulcrum of trunnion bar 41. Once trunnion bar 41 slips past stop 108 and into trunnion pocket 109, stop 108 may then prevent trunnnion bar 108 from sliding back out along the bottom of holding piece 101. For example, if packing panels 21 are engaged when container 40 is elevated, stop 108 may prevent trunnion bar 41 from exiting trunnion pocket 109 in response to operation of the packing panels 21. Thus, as long as the angle of the stop is sufficient as compared with the packing panel force 19, it may be very difficult, if not impossible to push trunnion bar 41 out of trunnion pocket 109, even when packing panels 21 of garbage truck 20 push garbage against wall 43 and trunnion bar 41 of container 40.
The forces on the container being raised with the tip bar 30 may be substantially different from when a container is being raised with a winch cable. As the container is initially being raised, tip bar 30 pushes against container 40 and thus towards the rear of the truck. Unlike being raised with the winch cable, if the locking bars 2 are not latched, container 40 will simply be pushed out of trunnion bar retention system 100. As container 40 is further raised with tip bar 30, the forces on the container cause trunnion bar 41 to move up to the top of the slot. Further raising will cause trunnion bar 41 to move down in the slot. It may be important to have a downward slope on the bottom of the trunnion bar retention system 100, including on stop 108, so that trunnion bar 41 will be urged into trunnion pocket 109 at the front. If trunnion bar 41 remains near the edge of hopper lip 25, materials and/or fluids may spill out onto the ground causing an undesireable situation. Stop 108 and trunnion bar pocket 109 may be configured so that trunnion bar 41 cannot be accidently restrained when container 40 is lowered by tip bar 30, and rotates around hopper lip 25.
Similarly, stop 108 may be a separate piece fixedly attached to holding piece 101, or may be integrally formed in holding piece 101. Stop 108 and holding piece 101 may be formed of any material suitable for use with garbage trucks such as iron, steel, other metal alloys, etc. The trunnion bar restraining systems described above may be very valuable in preventing human misery as well as saving significant costs for trucks employing such systems.
In addition to any previously indicated modification, numerous other variations and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of this description, and appended claims are intended to cover such modifications and arrangements. Thus, while the information has been described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred aspects, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, form, function, manner of operation, and use may be made without departing from the principles and concepts set forth herein. Also, as used herein, the examples and embodiments, in all respects, are meant to be illustrative only and should not be construed to be limiting in any manner.
This application claims priority to U.S. Provisional Patent Application No. 61/640,661, entitled: Trunnion Bar Restraining System for Rear Loading Garbage Trucks, and filed on Apr. 30, 2012, which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61640661 | Apr 2012 | US |