Patent Application
20190198003
This disclosure relates generally to trash collection and, more specifically, to an apparatus and method for reducing the noise generated when a dumpster is emptied into a garbage truck.
Trash collection has always been a noisy process. For example, a typical front loader garbage truck has two steel lifting forks projecting in front of the truck cab. The forks are connected to steel linkage arms that extend upwards and backwards over the cab, where they are hinged to the container portion of the truck. The driver pulls up to a dumpster, which is typically made of steel, and guides the lifting forks into metal fork pockets on each side of the dumpster. Once positioned, hydraulic actuators rotate the linkage arms to lift the dumpster upwards over the cab and then tip it upside down over the truck's container. The contents of the dumpster then empty into the truck container by gravity. Often, the driver will manipulate the hydraulics to rapidly “shake” the dumpster in an upward and downward motion to dislodge any remaining contents of the dumpster. The collection and emptying of the dumpster is notoriously noisy because the dumpster, forks, and fork pockets are all typically fabricated from high strength steel, resulting in metal-to-metal hammering.
As a result, trash collection companies, municipalities, and the like strive to schedule garbage collection times when it will have the least impact on their customers. In heavily populated areas, such as urban regions or hotels, scheduling collection at night or very early in the morning is discouraged because it may interrupt a customer's sleep. Some areas have enacted local ordinances defining “quiet periods,” during which the trash hauler is prohibited from waste collection. However, scheduling garbage collection later in the day may interfere with local traffic patterns or hotel operations. Thus, trash haulers must strike a balance between efficient routing of the garbage trucks and scheduling collection times that do not negatively impact the local community.
In accordance with one aspect of the disclosure, a dumpster noise mitigation apparatus includes a lifting fork having a base end configured to attach to a waste collection vehicle, a tip end configured to engage a fork pocket on a dumpster, an upper surface, and a bottom surface. The dumpster noise mitigation apparatus further includes a sound-dampening element secured to one of the upper surface and the lower surface. The sound-dampening element is secured without material removal from the surface of the fork.
In one embodiment, the dumpster noise mitigation apparatus further includes a slat secured to the lifting fork, and the sound-dampening element is secured to the slat.
In another embodiment, the dumpster noise mitigation apparatus further includes a fork ramp secured to the bottom surface of the tip end of the lifting fork. The fork ramp defines an angled surface extending from the tip end towards the base end.
In accordance with another aspect of the disclosure, a method for reducing the noise generated when a dumpster is emptied into a garbage truck includes the steps of providing a slat in the range of 0.5 inches, providing a sound-dampening element having a thickness in the range of 0.10-0.38 inches, securing the slat to one of an upper surface and a lower surface of a lifting fork, and securing the sound-dampening element to the slat. The step of securing the slat to the fork does not entail material removal from the fork surface.
The features described herein can be better understood with reference to the drawings described below. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views.
The inventor of the present invention studied the garbage collection noise problem by carefully observing the waste collection process and measuring the sound level. A recorded sound level of 108 dB was not uncommon during the data gathering, that level being equivalent to the sound level of a rock concert, and almost 16 times louder than a household vacuum cleaner or TV audio (70 dB). The inventor noted that the fork pockets are purposely oversized, presumably to prevent binding and to accommodate a wide variety of lifting fork configurations. As a result, there is a large clearance—on the order of several inches—between the fork and the inside surfaces of the rectangular pipe. Consequently, as the linkage arms lift and tip the dumpster from a horizontal position to an upside-down position, the dumpster is afforded a large amount of free movement, and the fork pockets loudly hammer against the lifting forks. The dumpster itself can amplify the sound level, since the dumpster is essentially a cavernous metal box structure. Furthermore, operators that rapidly “shake” the dumpster upward and downward to dislodge any remaining contents can further exacerbate the noise level problem.
Further study revealed that the majority of contact (e.g., banging) occurred against the top and bottom surface of the lifting fork, and to a smaller degree against the sides of the fork. Embodiments of the present invention provide noise mitigation solutions to the observed interaction between the lifting fork and the fork pocket.
Referring now to
In some examples, the tapering cross section of the fork is approximately square in shape, such that the horizontal and vertical cross sections are alike. In other examples, the tapering cross section of the fork is such that the horizontal cross section of the fork is smaller in dimension than the vertical cross section.
In the illustrated embodiment of the invention, the lifting forks 102 are tapered along a bottom surface 112 from the base end 108 to the tip of the forks such that the forks' vertical dimension is constantly changing along their length. The fork width (W) remains constant along the length of the forks on any particular truck but the width of the forks may vary from manufacturer to manufacturer.
The tip end 110 of the lifting fork 102 may include a rounded nose 114 and a vertically extending lip portion 116 that stops the dumpster fork pocket 3 from sliding off the fork. In one example, the height (H) of the lip portion 116 is approximately 1.50-1.75 inches.
The noise mitigation apparatus 100 further includes a sound-dampening element 118 secured to a surface of the lifting fork 102. In the illustrated embodiment, the sound-dampening element 118 is secured to an upper surface 120 of the lifting fork 102. However, it is contemplated the sound-dampening element 118 could also be secured to a bottom surface 112 of the fork.
In one embodiment of the invention, the sound-dampening element 118 may be fabricated from conveyor belt material, trimmed to the width (W) of the fork and secured with epoxy adhesive. In one example, the belt material may be a multi-ply construction, having an abrasion-resistant upper layer to withstand the day-to-day impacts with the dumpster fork pocket 3, and a matte or roughened bottom layer for better adhesion. Non-limiting examples of the top layer material may include black rubber, nitrile (NBR) impregnated polyester, or polyvinylchloride (PVC). Non-limiting examples of the bottom layer material may include interwoven fabric, monofilament fabric, polyethylene terephthalate (PET) fabric, or non-woven impregnated polyester. In one example, the conveyor belt material may be approximately 0.1 inches thick. In another example, the conveyor belt material thickness may be in a range between 0.10 and 0.25 inches. The sound-dampening element 118 may be approximately 48 inches in length to substantial cover most of the fork surface.
In another embodiment of the invention, the sound-dampening element 118 may be fabricated from a molded material, such as neoprene or fiber-reinforced neoprene. The material may be molded to size or trimmed to the width (W) of the fork and secured with epoxy adhesive. In one example, the molded sound-dampening element 118 may be 0.125 inches thick, with a rubber hardness of Shore 60A, which is similar to the hardness of a car tire tread. The sound-dampening element 118 may be approximately 48 inches in length to substantial cover most of the fork surface. In another example, the sound-dampening element 118 may be formed from Nylon MD, a nylon and molybdenum disulfide (MoS2) composition designed to improve the mechanical, thermal and lubricity properties of type 6/6 nylon.
In one example, the sound-dampening element 118 may be secured to the surface of the lifting forks 102 by an adhesive, such as an industrial two-part epoxy adhesive. In other examples, the sound-dampening element 118 may be secured to the surface of the lifting forks 102 by fasteners, or straps.
The lifting fork surfaces 120, 112 do not require any exceptional preparation prior to application of the sound-dampening element 118. For example, material removal is not necessary. The lifting fork surfaces 120, 112 may be prepped for bonding simply by a thorough cleaning to remove dirt and oils. The sound-dampening element 118 may be applied to the fork surfaces without interfering with the original functionality of the lifting fork, since the material is fairly thin (e.g., 0.1-0.250 inches) compared to, for example, the height (H) of the lip portion 116 (e.g., 1.625 inches). In other words, the thickness of the sound-dampening element 118 may be only 6%-15% of the lip height, which still leaves ample space for the lip portion 116 to perform its function. It is believed the thickness of the sound-dampening element 118 could be as much as 25% of the lip height without adversely impacting the function of the lip portion 116.
Referring now to
The sound-dampening element 218 may be similar in construction to that disclosed with reference to
In another example, the sound-dampening element 218 may be fabricated from a molded material, such as neoprene or fiber-reinforced neoprene. The material may be molded to size or trimmed to the width (W) of the fork (top and bottom) and secured with epoxy adhesive. In one example, the molded sound-dampening element 218 may be 0.125 inches thick, with a rubber hardness of Shore 60A.
The sound-dampening element 218, either the conveyor belt material, molded material, or other material, may be secured to the surface of the lifting forks 202 by an adhesive, such as an industrial two-part epoxy adhesive, or by fasteners or straps. Furthermore, the sound-dampening element 218 may be approximately 48 inches in length to substantial cover most of the upper and bottom fork surfaces.
Referring now to
Referring now to
In another example, the noise mitigation apparatus 400 may include a sound-dampening element 418c that extends along the fork bottom surface 412 as previously disclosed herein, but further includes a segment that at least partially covers the nose portion 414 of the lifting fork 402. Sound-dampening element 418c, which may comprise the same material as element 418a, can be secured in the same manner as element 418a, for example with industrial two-part epoxy adhesive. Sound-dampening element 418c can be adapted to mitigate the noise generated when the lifting forks 402 are not properly aligned and subsequently hit the dumpster fork pocket 3. Therefore, to prevent the sound-dampening element 418c from peeling or shearing away from the nose 414 when the fork 402 hits the fork pocket 3, in one example the sound-dampening element 418c extends about half way up the curved surface of the nose. In another example, the sound-dampening element 418c extends approximately one-third up the curved surface of the nose. In yet another example, the sound-dampening element 418c extends between one-third and two-thirds up the curved surface of the nose. And, in yet another example, the sound-dampening element 418c can extend upwards and cover substantially all of the fork nose 414.
One problem identified in engineering development trials of the disclosed invention was that the adhesive used to secure the sound-dampening element to the lifting forks did not endure as long as hoped. As a result, the sound-dampening element needed to be replaced, and the preparation time required to remove the old adhesive became quite consuming.
Experiments were conducted with several combinations of sound-dampening material and commercial adhesives, and although some proved useful and were advantageous for certain applications, a more enduring solution was sought that could be incorporated over a wider range of climate conditions and fork configurations. Furthermore, a sound-dampening element that could be easily removed and replaced was desirable.
Referring now to
In one embodiment of the invention, the slat 530 may be permanently secured to the lifting fork 502 by welding it along its side edge, as depicted by the weld seam 536 shown in
In one embodiment of the invention, the sound-dampening element 518 may be formed from Nylon MD, a nylon and molybdenum disulfide (MoS2) composition designed to improve the mechanical, thermal and lubricity properties of type 6/6 nylon. The material may be molded to size or trimmed to the width of the fork. In one example, the sound-dampening element 518 is 48 inches long, 1 inch wide, and 0.38 inches thick. The sound-dampening element 518 may further define a pattern of equally-spaced thru holes 538 to accommodate a fastener 534, such as a flat head hex socket cap screw. In another example, the sound-dampening element 518 may be formed from a molded material, such as neoprene or fiber-reinforced neoprene.
Another problem identified in engineering development trials of the disclosed invention was that, in configurations where there was no lip portion 516 on the fork, the sound-dampening element 518 was battered by the forward edges of the fork pocket 3 (
In one embodiment of the invention, the noise mitigation apparatus 500 may further include a fork ramp 540 and to protect the sound-dampening element 518 and alleviate the abrading problem. In the illustrated embodiment, the fork ramp 540 may be positioned where the fork tip 510 transitions to the bottom surface 512. The fork ramp 540 may include a rounded or angled surface 542 extending from the tip end 510 towards the base end 508. In one example, the angle may be approximately 30 degrees. The height of the fork ramp 540 may be equal to or greater than the combined thickness of the slat 530 and the sound-dampening element 518. In one example, wherein the slat 530 is 0.5 inches thick and the sound-dampening element 518 is 0.38 inches thick, the fork ramp 540 may be 1.5 inches long, 1 inch wide, and 0.88 inches high. The fork ramp 540 may be fabricated from steel and welded to the lifting fork 502, as depicted by the weld seam 536 shown in
Although the fork ramp 540 is shown protecting the sound-dampening element 518 on the bottom surface 512, it can also protect the sound-dampening element 518 on the upper surface 520 if no lip portion 516 is present.
Turning now to
The method 600 for reducing the noise generated when a dumpster is emptied into a garbage truck may include a step 620 to prepare the lifting fork surfaces for the securement of the sound-dampening element. In one example, the forks need only be cleaned of dirt and oils prior to application of an epoxy.
The method 600 may further include a step 630 for securing a sound-dampening element to the vertical surface of the fork to end. In one example, the sound-dampening element can be secured with an industrial two-part epoxy adhesive. At the bottom, the sound-dampening element can butt up against the upper surface of the fork. At the top, the sound-dampening element may not extend higher than the flat surface of the tip end of the fork nose. The sound-dampening element may also be recessed from (i.e., lower than) the flat surface of the tip end of the fork nose.
The method 600 may further include a step 640 for securing a sound-dampening element to an upper surface of the lifting fork. In one embodiment of the invention, the width of the element is no more than the width of the fork surface, such that there is no overhang. The sound-dampening element may be secured with an industrial two-part epoxy adhesive, strapped, or fastened. In another embodiment of the invention, the sound-dampening element can have a cross-section that takes the form of a channel, such that it fits snugly over the fork surface.
The method 600 may further include a step 650 for securing a sound-dampening element to a bottom surface of the lifting fork. In one embodiment of the invention, the width of the element is no more than the width of the fork surface, such that there is no overhang. The sound-dampening element may be secured with an industrial two-part epoxy adhesive, strapped, or fastened. In another embodiment of the invention, the sound-dampening element can have a cross-section that takes the form of a channel, such that it fits snugly over the fork surface.
The method 600 for reducing the noise generated when a dumpster is emptied into a garbage truck may include a step 660 to extend the sound-dampening element so as to at least partially cover the forward nose portion of the lifting fork. The sound-dampening element may extend about one-third up the curved surface of the nose. In another example, the sound-dampening element may extend approximately half way up the curved surface of the nose. In yet another example, the sound-dampening element may extend upwards and cover substantially all of the fork nose.
The method 600 may further include a step 670 to cure the industrial two-part epoxy adhesive. During the curing step, the sound-dampening element may be temporarily clamped to assure proper adhesion.
Turning now to
At a step 720, a sound-dampening element is provided for securement to the slat. In one example, the sound-dampening element may be fabricated from Nylon MD, trimmed to the length and width of the fork, and may be approximately 0.38 inches thick. The sound-dampening element may further define a pattern of equally-spaced thru holes to accommodate a fastener, such as a flat head hex socket cap screw.
The method 700 may further include a step 730 of providing a fork ramp and a step 740 of securing the fork ramp to the fork. In one example, the fork ramp may be positioned where the fork tip transitions to the bottom surface. The fork ramp may include a rounded or angled surface extending from the tip end towards the base end. In one example, the angle may be approximately 30 degrees. The fork ramp may be welded to the lifting fork along its side edge.
The method 700 may further include a step 750 for securing the slat to the bottom surface of the lifting fork. In one example, the slat may be permanently secured to the lifting fork by seam welding along its side edges.
The method 700 may further include a step 760 of securing the sound-dampening element to the slat. In one example, the securement is provided by flat head hex socket cap screws.
One of the improvements of the disclosed noise mitigation apparatus and method is that the noise generated during dumpster emptying can be reduced by about 10 dB, or 50%. This significant reduction can allow trash haulers to open their schedules and thereby schedule routes more efficiently.
While the present invention has been described with reference to a number of specific embodiments, it will be understood that the true spirit and scope of the invention should be determined only with respect to claims that can be supported by the present specification. Further, while in numerous cases herein wherein systems and apparatuses and methods are described as having a certain number of elements it will be understood that such systems, apparatuses and methods can be practiced with fewer than the mentioned certain number of elements. Also, while a number of particular embodiments have been described, it will be understood that features and aspects that have been described with reference to each particular embodiment can be used with each remaining particularly described embodiment.
Reference is made to and this application claims priority from and the benefit of U.S. Provisional Application Ser. No. 62/610,151, filed Dec. 23, 2017, entitled “APPARATUS AND METHOD FOR MITGATING DUMPSTER NOISE”, which application is incorporated herein in its entirety by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62610151 | Dec 2017 | US |
