Embodiments of the present invention generally relate to loading objects onto vehicles, tilting objects loaded on the vehicles for dumping, and unloading the objects from vehicles.
Trucks are frequently used to load, transport, unload, and sometimes dump containers holding various types of material. These trucks sometimes use lifts attached to the truck to load the containers onto the truck, hold the containers on the truck during transport, hold the containers while being tilted to dump the contents out of the containers, and offload the containers from the truck. For example, the waste and recycling industries frequently use lifts attached to trucks to transport and dump waste and recycling containers (one example being the Dumpster® brand trash receptacle). One type of lift, commonly referred to as a cable hoist, uses a winch to pull a cable the operator has connected to a container and draw the container onto the truck. Tow trucks (also referred to as wreckers) commonly use cable hoists and a tilting flat bed to onload and offload vehicles. Vehicle-mounted lifts are another type that use a rigid hook assembly to connect with the container to be onloaded, offloaded, and/or dumped. See, e.g., U.S. Patent Application Publication No. 2007/0092364 A1, published Apr. 26, 2007 to Geise et al.
Difficulties exist with current vehicle-mounted lifts for loading, unloading and dumping. For example, some vehicle-mounted lifts become unstable while onloading, offloading and/or dumping containers. Other vehicle-mounted lifts require the vehicle operator to exit the vehicle's cab during the loading, unloading and/or dumping process. Still other vehicle-mounted lifts use multi-stage hydraulic cylinders (those with multiple telescoping piston sections), which are more complicated, more prone to leaking, and more prone to break-down than single-stage hydraulic cylinders. Other vehicle-mounted lifts place high stress loadings at critical points in the system that can fail during loading and/or unloading, creating an unsafe situation. Still other vehicle-mounted lifts use cables but allow the cables to become slack, which frequently results in the cables misfeeding, binding and breaking.
Some vehicle-mounted lifts use a hydraulic cylinder and a ratcheting system to incrementally move the container onto the vehicle; however, these hoists are slow, may require the operator to command the hydraulic piston to the extended and retracted position numerous times to load a container, and have complicated ratcheting systems that require additional maintenance, use special/expensive containers with numerous ratchet connectors, and pose safety risks if the ratcheting system fails. Still other vehicle-mounted lifts use long cables wrapped around a number of pulleys; however, these lifts are complex and the large number of pulleys and the long length of the cable create excess play and/or bounce in these vehicle-mounted lifts.
One embodiment of the present invention includes a vehicle-mounted lift with a tiltable frame assembly that is connectable to a vehicle, such as a truck. One or more lift cylinders lift the forward end of the frame for loading containers, unloading containers, or dumping the contents of the containers while the containers remain on the tilted frame. A hook assembly is mounted to the frame assembly and travels along the length of the frame assembly. The hook assembly includes a hook that engages the container and pulls the container onto the frame.
The vehicle-mounted lift also includes a cable reeving system that moves, such as by pulling or drawing, the hook assembly along the length of the frame. The cable reeving system acts as a distance multiplier and uses the force generated by a hydraulic cylinder to move the hook assembly carriage a greater distance than the distance the end of the piston rod moves. The cable reeving system is capable of moving the hook assembly the full length of the frame and the full length of the extended hydraulic cylinder from the base of the piston to the tip of the fully-extended piston rod using a single-stage hydraulic cylinder despite the piston and piston rod each occupying a length along the frame that is considerably longer than the length along the frame the hook assembly occupies and considerably shorter than the distance along the frame the hook assembly travels. The cable reeving system also maintains the cables taut, which minimizes the misfeeding, binding and breaking of the cables.
Embodiments of the present invention provide an improved vehicle-mounted lift adapted to load, unload and dump a container.
Other embodiments of the present invention include a cable reeving system for loading, unloading and dumping containers.
Still other embodiments provide an improved vehicle-mounted lift with a rear hinge assembly that moves the rear end of the hoist frame downward and positions a stabilizer against the support surface to stabilize the vehicle during loading, unloading and dumping.
This summary is provided to introduce a selection of the concepts that are described in further detail in the detailed description and drawings contained herein. This summary is not intended to identify any primary or essential features of the claimed subject matter. Some or all of the described features may be present in the corresponding independent or dependent claims, but should not be construed to be a limitation unless expressly recited in a particular claim. Each embodiment described herein is not intended to address every object described herein, and each embodiment does not necessarily include each feature described. Other forms, embodiments, objects, advantages, benefits, features, and aspects of the present invention will become apparent to one of skill in the art from the detailed description and drawings contained herein.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the selected embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is hereby intended, such alterations, modifications, and further applications of the principles of the invention being contemplated as would normally occur to one skilled in the art to which the invention relates. At least one embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features or some combinations of features may not be shown for the sake of clarity.
A vehicle-mounted lift 100 according to one embodiment of the present invention is depicted in
In
Depicted in
Cable reeving system 102 includes an actuator (for example, single-stage hydraulic cylinder 140) that is attached to frame 115 and applies force against the middle portion of a cable assembly (for example, front cable 111 or rear cable 112) to pull carriage assembly 125 along frame 115. One end of each cable is attached to the frame 115 and the other end of each cable is attached to carriage assembly 125.
Cables, as used herein, are intended to mean and include elongated load-bearing members (such as wire ropes, chains and non-wire ropes) that are sufficiently flexible to be disposed around and operate in conjunction with one or more pulleys or bearing members while being sufficiently strong to pull a desired load.
Hydraulic cylinder 140 is connected to and utilizes a traveler assembly 104 to apply forces to the cables. Traveler assembly 104 is supported by frame assembly 115, and travels forward and backward relative to frame assembly 115. Referring to
Carriage assembly 125 (and hook assembly 120) move the full length of the frame assembly 115 in response to hydraulic cylinder(s) 140 moving traveler assembly 104 forward and backward along frame 115. Front cables 111 and rear cables 112 remain taut and engaged with pulleys 108 and 106 irrespective of the movement of traveler assembly 104.
In use, hydraulic cylinders 140 (each of which includes piston cylinder 141 and piston rod 142, see
As depicted in
The movement of traveler assembly 104 in direction 154 results in rear cables 112 (which are disposed around forward pulleys 106) being the active cables pulling carriage assembly 125 in direction 155 and performing at least a majority, if not all, of the work to move carriage assembly 125 along frame 115. Conversely, when traveler assembly 104 is moved opposite to direction 154, front cables 111 (which are disposed around rear pulleys 108) are the active cables pulling carriage assembly 125 opposite to direction 155 and performing at least a majority, if not all, of the work to move carriage assembly 125 along frame 115 and opposite to direction 155.
If the forward end 116 of frame assembly 115 is raised (thereby raising forward pulleys 106 above rear pulleys 108), rear cables 112 and forward pulleys 106 become active to prevent carriage assembly 125 from moving rearward. In this example, moving carriage assembly 125 rearward is accomplished, at least in part, by allowing gravity to pull carriage assembly 125 opposite to direction 155 while rear cables 112 acting via forward pulleys 106 control the rate at which carriage assembly moves toward the rear end 117 of frame 115.
Hydraulic cylinder 104, as depicted in
Since the front 111 and rear 112 cables are each disposed around a single pulley and the overall length of front 111 and rear 112 cables are kept to a minimum, the total number of pulleys is minimized, the overall complexity of the cable reeving system is minimized, and the free-play and bounce that can occur with longer cables (especially when disposed around multiple pulleys) is also minimized.
Although cable reeving system 102 is depicted in
In still further embodiments, a long single cable with a length approximately equal to the combined lengths of a front cable 111 and a rear cable 112 is used in place of a front 111 and rear 112 cable pair. In these embodiments, one end of the single cable is attached to the rear end 117 of frame assembly 115 and the other end of the single cable is attached to the forward end 116 of frame assembly 115 with the single cable being disposed around both a forward pulley 106 and a rear pulley 108. A portion of the single cable disposed between forward pulley 106 and rear pulley 108 is attached to carriage assembly 125 to move carriage assembly 125 in the forward and rearward directions. (It should be appreciated that if the single cable in these embodiments were bisected at a location where the single cable attaches to carriage assembly 125 and the two additional ends of the cable created by the bisection were each attached to carriage assembly 125, an embodiment similar to that depicted in
Additionally, although the figures depict the cable reeving system actuators (hydraulic cylinders 140) as being attached to the rear end 117 of frame 115, it should be appreciated that one or more actuators may be attached to any location where the actuators can move traveler assembly 104 forward and/or rearward relative to frame 115. For example, the actuators may be connected to the forward end 116 of frame 115. The actuators may also be connected to the sides of frame 115, such as when traveler assembly 104 includes a toothed bar (rack) and the actuator includes a toothed gear (pinion) that engages and applies force to the toothed bar.
Moreover, while the actuators associated with cable reeving system 102 are depicted as being single-stage hydraulic cylinders, it should be appreciated that other forms of actuators may be utilized. For example, multi-stage hydraulic cylinders may be utilized, although some advantages associated with using single-stage cylinders instead of multi-stage cylinders would generally not be realized in these embodiments. As another example, rack and pinion or jack screw type actuators may also be utilized.
The rear end 117 of frame 115 is attached to the vehicle with hinge assembly 200, which uses multiple pivot points and includes one or more forward links 203 and one or more rear links 205. One end of each forward link 203 and one end of each rear link 205 is pivotally connected to the frame assembly 115. The other end of each forward link 203 and each rear link 205 is pivotally connected to the frame of truck 80.
With the frame in the stowed position, the forward 203 and rear 205 links form a V-type configuration with each link angling upward and away from the other link, but with the lower ends of the links being separated. Attached to the rear portion of the tiltable frame is a stabilizer, which in one variation is a roller.
Depicted in
As depicted in
The attachment location 203b between forward link 203 and the frame of truck 80 is also forward of and above the attachment location 205b between rear link 205 and the truck frame. Still further, the distance between the locations at which rear hinge assembly 200 attaches to frame 115 (the distance between attachment locations 203a and 205a) is greater than the distance between locations at which rear hinge assembly 200 attaches to the frame of truck 80 (the distance between attachment locations 203b and 205b). Moreover, the effective length of forward link 203 (the distance between attachment locations 203a and 203b) is also longer than the effective length of rear link 205 (the distance between attachment locations 205a and 205b) in the illustrated embodiment.
When lift cylinder(s) 135 extend and the forward end 116 of frame assembly 115 is raised, the rear portion 117 of frame assembly 115 begins moving rearward and downward due to the arrangement of rear-hinge assembly 200. When the forward end 116 of frame assembly is raised sufficiently, stabilizer 215 (depicted as a roller attached to the rear end 117 of frame 115) contacts the support surface 90 (e.g., pavement). The contact between stabilizer 215 and the support surface 90 increases the stability of truck 80 and maintains the front end of the truck 80 on the support surface 90 as container 85 is loaded and/or unloaded.
The loading and dumping of a container 85 according to one embodiment of the present invention is depicted in
If stabilizer 215 has been placed in contact with the support surface prior to the operator backing truck 80 up to container 85, the round cylindrical shape of stabilizer 215 and its ability to rotate about its longitudinal axis decreases wear and tear on the stabilizer 215, the rear end of frame 117, the rear hinge assembly 200, and truck 80, and facilitates the placement of hook assembly 120 in contact with container 85. Additionally, the preferably open (see-through or non-enclosed) nature of vehicle-mounted lift 100 allows the operator to view container 85 through frame assembly 115, enhancing the operator's ability to appropriately position hook assembly 120 with respect to container 85.
Once hook assembly 120 is appropriately positioned to engage container 85, the operator extends the cable reeving actuators (cylinders 140, see
Once container 85 reaches a location where the forward end 116 of frame assembly 115 can be lowered, the operator will frequently retract lift cylinders 135 to decrease the incline up which container 85 is pulled and, thereby, decrease the force required to continue moving hook assembly 120 and container 85 toward the forward end 116 of frame assembly 115.
Once container 85 has been pulled a sufficient distance onto frame assembly 115, the operator retracts lift cylinder(s) 135 to fully lower frame assembly 115 onto truck 80 (see
To dump a payload of material located within container 85, the operator maintains hook assembly 120 at the forward end 116 of frame assembly 115 and extends lift cylinder(s) 135 (see
Although the above description refers to containers being loaded, unloaded and tilted/dumped by the vehicle-mounted lift, the term “container” is not intended to be limiting and other objects that may or may not meet the definition of a container are contemplated as being loaded, unloaded and tilted/dumped by the disclosed vehicle-mounted lift.
Moreover, although the front and rear cable engaging members of traveler assembly 104 are depicted as being pulleys, for example forward pulleys 106 and rear pulleys 108, other embodiments of the present invention utilize alternate mechanisms for engaging the flexible members (cables) that are connected to frame 115 and carriage assembly 125. For example, alternate embodiments use toothed and/or non-toothed gears engaging chains, while still other embodiments use low friction bearing surfaces or couplings such as one or more curved members coated with a low friction lubricant or compound (for example, Delrin® manufactured by DuPont E I de Nemours & Co.) to apply force to an intermediate portion of the cable/rope/chain that is connected to the carriage assembly.
Furthermore, although carriage assembly 125 is depicted as using rollers or wheels to decrease the friction between carriage 125 and frame 115, it should be appreciated that other means of reducing the friction between carriage 125 and frame 115 may be used. For example, low friction coatings such as Delrin® or various types of lubricants may be used to decrease the friction between carriage 125 and frame 115 as carriage 125 slides along frame 115.
Furthermore, although the lift cylinders and actuators described herein are generally described as being hydraulic cylinders, other types of force generating members may be used provided sufficient force can be applied to accomplish the desired task. For example, electrically powered actuators, pneumatically powered actuators, and other types of actuators, such as those utilizing jack screws, may be used.
While illustrated examples, representative embodiments and specific forms of the invention have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive or limiting. The description of particular features in one embodiment does not imply that those particular features are necessarily limited to that one embodiment. Features of one embodiment may be used in combination with features of other embodiments as would be understood by one of ordinary skill in the art, whether or not explicitly described as such. Dimensions, whether used explicitly or implicitly, are not intended to be limiting and may be altered as would be understood by one of ordinary skill in the art. Exemplary embodiments have been shown and described, and all changes and modifications that come within the spirit of the invention are desired to be protected.