Patent Application
20080128668
This invention relates to devices for moving an object by pulling on two or more tensile elongate elements to which the object is attached. More particularly, the invention relates to a device that attaches to and preferentially pulls on multiple ropes or cables for positioning a load in multidimensional workspaces.
Existing methods of gaining access to large vertical faces such as the sides of buildings or rock faces are limited to either minimal 1-dimensional access capabilities, such as single rope rappelling systems for climbers, rescuers, or window washers, or large, bulky installations such as cranes, scaffolding, or external elevators.
Window washing systems that utilize standard rappelling equipment are limited in their access to the side of a building by the single line from which the operator hangs. In order to move laterally for any significant distance, the operator must descend to the bottom of the building, return to the rooftop and reposition his line, and then re-descend to the desired position. Similarly, climbers and rescue personnel who wish to access a specific point on a rock face or other vertical site must descend from directly above the desired position. When access to the ideal starting position above the target is not available, the operator may face extreme difficulty in accessing the desired position and must resort to additional support personnel or equipment to provide lateral movement capabilities.
For large buildings where it may be appropriate to do so, scaffolding systems can be set up, either stationary or movable, to provide 2 dimensional access to the entire building face where needed. However, any system capable of providing such access requires significant cost, space, setup time, and operation time. Alternatively, ground lift systems such as cranes or vertical hoists can be used, but face similar limitations of cost, space, and access provided.
A device that can be quickly, cheaply, and easily deployed which can give an operator precise, safe, and reliable access to vertical workspaces, such as sides of buildings and rock faces, would be of significant benefit to a variety of users. Rescue personnel could descend from a high point adjacent to the victim, instead of directly from above, and approach them laterally without disturbing loose and potentially dangerous objects, overhead obstacles, or the victim. Window washers could access an entire building face without needing to reset overhead lines, and construction workers could deliver equipment and personnel quickly and easily to many points on a high worksite. Additional functionality could be found in the entertainment industry, running high wires to pull actors into the air and manipulate their position in 2 dimensions remotely without the need for overhead rolling track carrier systems, as well as other setups where such carrier systems are needed. Other uses include installing, positioning and uninstalling overhead speaker and light systems at concerts and sporting events, as well as positioning camera systems.
Similarly, positioning loads in 3 dimensional spaces is commonly accomplished by large, bulky systems such as overhead gantries or cranes that are not designed for portability or low cost. The ability to use a single low-cost device to accurately position loads, including workers, could be significantly advantageous for situations where a load manipulation system must be modular, quickly deployable, or able to fit and maneuver in confined spaces. Still another application where a 2 or 3 dimensional load positioning system would have further advantages over existing load positioning technology such as conventional hoists with swinging booms is in a hospital, where heavy patients must be maneuvered from stretchers to operating tables. Conventional hoists with swinging arms are impractical because the trajectory of the boom and the patient require that the entire area be clear to avoid collisions with equipment.
It is therefore an object of the present invention to provide an apparatus for lifting or pulling heavy loads and controlling their position in 1, 2 or 3 dimensions which solves one or more of the problems associated with the conventional methods and techniques described above.
Another object of the present invention is to position loads vertically by ascending or descending a rope or cable fixed above the load.
Another object of the present invention is to optionally utilize one or more ropes or cables affixed overhead and at a distance from one another in order to facilitate two dimensional or three dimensional positioning of a load, be it a person or an object.
It is also an object of the present invention to be able to manipulate a single rope, so that if multidimensional positioning is not required, the same device can still be utilized for powered ascent and descent in a single dimension.
It would also be desirable to be able to attach any such rope pulling device to a rope at any point along that rope without having to thread an end of the rope or cable through the device. This would increase the usability of such a device considerably over other rope pulling and climbing devices, allowing for example a user to attach the load or himself to the device for ascent that starts at an elevation well above the lower end of the rope.
Other objects and advantages of the present invention will be apparent to one of ordinary skill in the art in light of the ensuing description of the present invention. One or more of these objectives may include:
Still further objectives and advantages are to provide a rope or cable pulling device that is as easy to use as a cordless power drill, that can be used in any orientation, that can be easily clipped to a climbing harness, Swiss seat, or other static load suspension equipment, that can be just as easily attached to a grounded object to act as a winch, that is powered by a portable rotational motor, and that is lightweight and easy to manufacture.
While a number of objectives have been provided for illustrative purposes, it should be understood that the invention described below is not limited to any one of the illustrative objectives. It should further be understood that these illustrative objectives are stated in terms of the inventors' view of the state of the art, the objectives themselves are thus not prior art or necessarily known beyond the inventors.
The invention provides a multiple-rope or multiple-cable pulling device that preferably accomplishes one or more of the objects of the invention or solves at least one of the problems described above.
In a first aspect, a device of the invention includes an electronic controller that interprets a user's input from an interface such as a trigger or a joystick, and preferentially activates electronically controlled motors that drive one or more rope pulling mechanisms, such as winches. When the winches pull in or pay out cable in accordance with the controller's demand, the load is moved along the desired trajectory as specified by the user through the device interface.
An embodiment of the invention can be incorporated into a convenient portable hand-held motorized device, and in particular, can be configured as a portable hoist. Further aspects of the invention will become clear from the detailed description below, and in particular, from the attached claims.
The present invention can provide a useful solution because at minimum, its operation only requires the space of the straight-line trajectory through which the load and the ropes must move, as opposed to conventional boom hoists which require a larger work volume to accomplish the same movement. Additionally, the installation of the present invention to accomplish multidimensional load movement can be much lower profile and lower impact than that of a conventional hoist, by requiring only either 2 or 3 stationary fixture points for operation.
By utilizing a two-rope device, the operator can position the load or himself anywhere along a vertical plane passing through the two rope connection points by independently and simultaneously controlling and adjusting the lengths of the ropes actively fed through the device during its operation. Note that the load, here, can be an object, a person, or the operator, and that the ropes can be replaced by cables or other tensile elongate elements.
By utilizing a three-rope device, the user can position the load anywhere within a three dimensional space. By adjusting the relative lengths of rope above the device, its position can be controlled to anywhere within the volume of space projected downward from the three rope attachment points. Note again that the load, here, can be an object, a person, or the operator, and that the ropes can be replaced by cables or other tensile elongate elements. For greater load carrying capacity or movement within geometrically constrained spaces, such as a warehouse with tall items obstructing the desired path of the load, a device capable of manipulating 4 or more ropes could be utilized to provide added positional control beyond the capability of a 2 or 3-rope device.
The control of a multiple rope device can be achieved through a variety of configurations. One configuration consists of the device presenting to the operator one interface for each of the ropes passing through the device, be it a trigger, a switch, or a joystick. In this case, the operator manually controls the relative lengths and speeds of the ropes passing through the device, causing the ropes to move in the upwards or downwards directions as needed.
A second configuration consists of the device presenting to the operator an interface, for example a joystick, that allows the operator to input his intended direction for the load, whereby the device computes and automatically adjusts the incoming and outgoing rope lengths and speeds to accomplish the task. In the two rope device case, with the device and operator positioned with one attachment point above and to the left and the other attachment point above and to the right, the operator can input, for example, an up, down, right, or left intended direction on the interface in order to move in that direction. Intended diagonal directions, such as up-left, up-right, down-left, and down-right could also be accepted and delivered by the device. Such a configuration would be very useful for positioning the load within a plane, for example against a wall.
This configuration can be extended to three dimensional positioning within a volume, where again the operator inputs an intended direction and speed, and the device computes and delivers the corresponding three rope feed rates to move the load in the intended direction at the intended speed.
A third configuration consists of the device operator himself acting as the device controller. The operator may manually indicate rope directions and speeds independently of one another by squeezing a single trigger associated with each rope, or by manually activating each respective motor controller by some other means. One such configuration for 2 dimensional movement would comprise 2 triggers, each corresponding to one rope. The operator would pull a trigger to pull in rope, and pull a second trigger or button to release that rope. A parallel setup would correspond to the second rope. By preferentially pulling in and paying out ropes via manual control, the operator can move himself or the load along the desired trajectory. This means of control may also serve useful as a backup in conjunction with any automated controller associated with the device. A person of ordinary skill in the art will note that this manual control setup can be extrapolated to 3 rope, and thus 3 dimensional control, and even additional ropes beyond 3 as a situation may call for.
Referring now to
A user of device 100 provides an input to the device through the user interface 112 in accordance with the direction he wants to move the load, be it an object, another person, or himself. The device control 114 interprets the command and sends applicable signals to the speed controls 116, 118 in charge of each of the rope interaction mechanisms 120, 122. The signals are such that each of the mechanisms will create a velocity vector V1, V2 along its own rope 124, 126, which will sum with the velocity vector of the other rope or ropes to create the desired load trajectory. Sensors 128, 130 detecting the angle θ1, θ2 of the ropes with respect to vertical to provide position feedback to the device controller 114, which then updates the necessary speed of each rope feed 132, 134 to maintain the desired trajectory. The equation describing the velocity vectors of each rope as dependent on the respective angles of each rope to vertical is as follows:
Where V1 is the velocity of the first rope being pulled toward the device, V2 is the velocity of the second rope being pulled toward the device, θ1 is the angle that the first rope enters the device, θ2 is the angle that the second rope enters the device, VX is the component of the intended velocity in the X direction, and VY is the component of the intended velocity in the Y direction. Note that θ1 and θ2 are measured clockwise from vertical at the points where the first rope and second rope enter the device, respectively.
The intended velocity, VLOAD, is inputted by the operator through the user interface 112, via a joystick for example, and is proportional to the degree to which the joystick is pressed by the operator in a given direction. VLOAD is then decomposed into velocity components VX and VY. At times, VX and VY can be negative or zero.
While closed loop feedback control could be used with this embodiment of the invention, it is not required for operation of device 100. With each side of the device under manual control, for example, offering a proportional speed trigger for each rope interaction as the user interface, a user could still achieve satisfactory 2 or 3 dimensional positioning capability by controlling each vector separately.
Once the device controller 114 determines the requisite motor speeds to accomplish the desired trajectory, it sends velocity signals to the respective speed controllers 116, 118, which then activate the motors 136, 138, and optionally gearboxes 140, 142, accordingly. The motors 136, 138 and gearboxes 140, 142 then provide rotational power to the rope pulling mechanisms 132, 134, which pull the ropes through the device 144, 146. A person skilled in the art will note that it is easy to enable remote operation of the device by separating the user input physically from the invention itself. User input would then be relayed to the device either through a remote cable, a wireless communication device, or other remote means.
In a preferred embodiment of the invention, DC motors are utilized for their high power and low weight, though a person skilled in the art will note that the functionality of the device can be enabled by any powered rotational motor, or other power delivery mechanism. An exemplary power source 148 for powering the motors, as well as the device controller, could be a battery, especially a rechargeable batter such as a lithium ion battery.
A rope pulling mechanism is referenced in
In one embodiment, the rope pulling mechanisms comprise a rotating drum that is connected to the motor, either directly or through a gearbox (if one is present). It is the rotating drum, generally in the manner of a capstan, that applies the pulling force to the rope that is pulled through the device 100. In one embodiment, the rotating drum provides anisotropic friction gripping of the rope. In particular, the surface of the rotating drum can be treated or configured so that large friction forces are created in the general direction of the pulling of the rope (substantially around the circumference of the drum), and smaller friction forces are created longitudinally along the drum so that the rope can slide along the length of the drum, particularly when guided in such a manner by a rope guide, with relative ease. In other configurations, including when the rope runs over the drum for less than one full revolution of the drum, vanes on the drum can guide the rope to the center of the drum where those or other vanes help to grip the rope for pulling by the rotating drum. Such vaned drums are illustrated in
The rope pulling mechanism, any associated rope guide, or the device 100 itself or one of its elements, may also include a brake for holding the rope or ropes. The brake may be manual actuated, electrically actuated upon a signal from the device controller 114, and/or may operate continuously in a one way or ratchet mode in which the rope may be pulled through the device in a direction that allows the load to be lifted, but grabs or brakes movement of the rope if the device begins to slip down the rope or ropes.
In the illustrated embodiment, the rope pulling mechanisms 132, 134 and control elements 114, 116, 118 are integrated into a single unit 100. This embodiment can provide advantages when the operator is the “load” 110. That is, a single integrated unit 100 for lifting or moving the operator is advantageous in that the operator can use the user interface 112 to operate the device while the operator is being lifted or moved. In other embodiments, the user interface 112, for example, could be separated from the device 100 so that an operator could operate the device 100 remotely to lift or move a load 110 other than the operator. Similarly, the rope interaction mechanisms 120, 122 could be separated and not provided in an integral unit 100. Such an embodiment might be useful under certain circumstances to provide orientational stability for a large load—for example, a large rectangular load might have four rope pulling mechanisms, one on each top corner of the load, with all of the rope interaction mechanisms communicating with a common user interface 112 and controller 114. In such an embodiment, each rope interaction device 120, 122 could be provided with its own power source 148.
A rope or cable 124, 126 is also referenced in
A further embodiment of a device for positioning a load 200 is illustrated by reference to
In a further embodiment of the invention, as shown in
In another embodiment, the device may be fixed with respect to ground, and the ropes or cables are guided to the load via pulleys located on ceilings, walls, or other fixture points. In cases such as this, where the cable position with respect to the device would not change as a function of load position due to both the device and the first pulleys being fixed with respect to ground, the angular position feedback sensors would need to be located either at the load attachment point or at the last pulley before the load, where the angles of the ropes with respect to a fixed reference such as horizontal or vertical would change as a function of the load's position.
For safety, an electromechanical safety brake 23 is attached to the back of each motor 22. Such a safety brake requires electrical power to disengage. Before applying power to the motor 22, the motor controller 25 must apply power to the safety brake 23 to release its grip on the back end of the motor shaft. Upon release, the motor 22 can rotate and power the rope interaction to which it is attached. When in the unpowered locked position, the brakes provide a mechanical lock to the rope interaction mechanisms that prevents unwanted motion of the device and load. Thus, even upon power failure, the device and load will remain safely held in place. A person skilled in the art will note that such a brake could be installed on either end of either the motor or gearbox to achieve this safety functionality. Additionally, any suitable power-off brake, whether pneumatically, mechanically, or otherwise released, can provide the same safety functionality as described.
The illustrated embodiments can utilize a high-power DC electric motor, as built by Magmotor Corporation of Worcester, Mass. (part number S28-BP400X, for example) which possesses an extremely high power-to weight ratio (over 8.6 HP developed in a motor weighing 7 lbs). The power source can include batteries such as 24V, 3 AH Panasonic EY9210 B Ni-MH rechargeable batteries. The device incorporates a pulse-width modulating speed control, adjusted by the device controller, that proportionally changes the speed of the motor. The controller can be implemented on a variety of digital microprocessor devices with instructions and calculations coded in software, firmware, or the like.
A person of ordinary skill in the art will recognize that a variety of sensors will suffice to provide positional feedback to the device controller. In the preferred embodiment, angular sensors located on the device indicate the rope's angle with respect to a fixed reference, such as horizontal or vertical. In the alternative embodiment, the angular sensors can be located on the overhead rope pulling mechanisms or at the load attachment point. Other examples of sensors that could work include but are not limited to: rotary encoders on the motors or the outputs of the rope pulling mechanisms, linear or rotary sensors in contact with the rope, optical sensors on the device detecting the length of rope pulled through, and accelerometers on the device that provide inertial position, velocity or acceleration feedback.
A person of ordinary skill in the art will also recognize that the configurations described above are not the only configurations that can employ the principles of the invention. The system and method described above, utilizing multiple rope or cable pulling mechanisms to position loads in 2 and 3 dimensions, can be practically employed in other configurations. While certain features and aspects of the illustrated embodiments provide significant advantages in achieving one or more of the objects of the invention and/or solving one or more of the problems noted in conventional devices, any configuration or placement of all the parts, user interface, device controller, speed controller, power source, gearbox, sensors, and rope pulling mechanisms with relation to one another or to ground could be deployed by a person of ordinary skill in keeping with the principles of the invention.
This application claims priority to U.S. Provisional Patent Application Ser. No. 60/858,775, entitled Multiple Line Powered Rope Ascender and Portable Hoist, filed on Nov. 14, 2006, which application is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60858775 | Nov 2006 | US |
