Patent Search

1. Patent Number US5933898A: Portable Wheelchair Ramp

This patent details a portable ramp that can fold into a more compact area using hinges. The ramp consists of three sections, which are attached to one another by hinges that are built into each section. Two raised ridges run along the outer edges of each section to prevent the wheelchair from slipping off one of the sides. There are smaller panels are either end of the ramp to facilitate an easy transfer between the ground and the ramps surface. The hinges allow the outer panels to fold over the middle panel so that the device may be transported in a more compact box shape. There is also a handle attached to the center panel to allow the user to easily carry the ramp from place to place.

 

This design pertains the WNY accessibility project mainly because of its portability. The ramp that the project team has designed also folds into a box shape by utilizing hinges. The hinges in this design are part of the panels so the hinges for the WNY independent living design should be sufficiently different so that there is no infringement. One of the most interesting features of the ramp is that it takes up very little space when folded up. This ramp is designed to only go up small distances and therefore does not need legs. The folding design does seem rather intuitive and seems like it can easily be adapted to include legs. This would allow it to achieve a higher vertical travel that is necessary for the WNY independent living project. The idea of using a handle was something that the project team had not previously considered but could greatly add to the ease of transportation of the product. The main reasons that this patent is important is that if features a folding design that must not be infringed on and it also has several features that could help make the ramp for WNY independent living better. One last important thing to note is that this patent expires this year so some of the ideas can soon be used in new products.

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2. Patent Number  US6484344: Retractable Access Ramp

The patent for the “Retractable Access Ramp”, invented by Simon M. Cooper, describes a self – contained ramp system that can be extended to fit a set of stairs. The document describes a ramp that extends from a fixture that would be mounted flush with the level of the elevated area. The fixture has a void in which the extendable ramp is stored. The ramp can be extended from the fixture via rollers connected to each section of the ramp. Once the first section has reached it’s maximum extension, the second section will extend beyond the first and so on until the ramp reaches the ground level. On the ground level, the ramp is coupled to a flush – mounted base assembly that provides a smooth transition for a wheelchair to continue rolling. The ramp will be secured to the base and top assemblies via removable arresting pins and brackets.

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This concept provides a compact solution that could be adopted to our mobile bandshell accessibility ramp, however it does pose some concerns that would need revisions for our project. First being the lack of hand rails. The hand rails are a very important part of a ramp system for someone who may not be in a powered wheelchair. Secondly, the patent makes no mention of a non-slip surface. This would be required for a ramp of this pitch. Lastly, the pitch of a ramp like this would be an issue for us. From ADA guidelines, a ramp must have a 12:1 pitch, meaning 12 inches of length for every vertical inch. For our proposed project, the ramp would need to be 48 feet long, and likely that much ramp would not fit within the housing, and would likely also require additional support legs. Although this concept would be very compact, and could be adapted to the mobile band shell, significant design changes would have to happen for this to be feasible.

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3. Patent Number  :Accessibility Means for a Person Using a Wheelchair

This patent is for a product that allows wheelchairs to overcome obstacles. This device utilizes the obstacle to hold the device. It is comprised of two C channels that are held together with a rod keeping them separated at the correct distance. The C channels can then be laid over the obstacle such as stairs so that the user can use the stairs as a ramp. The biggest issue with this design is stairs are built at a steeper grade than the 8.33% allowed by the ADA. However when this device is used with a smaller grade it is a great solution. The device is lightweight and portable because it can collapse down. This product is meant to be a cost effective way to bring accessibility to locations otherwise not accessible to those in wheelchairs. For our specific application this device would not work. Our device must be able to bring a passenger up 4 vertical feet. For this design to work it would need support legs. A design feature to take away from this product is the C channels. Utilizing this geometry will enable the ramp to hold a tremendous amount of weight. The overall goal of this product is similar to our application therefore the patent application will be similar to ours if we decide to apply for a patent.       

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4. Patent Number US3818528: Portable Ramp for Wheelchairs and the Like

This is a portable ramp comprised of longitudinal ramp members that are placed side by side. This ramp can be folded both laterally and end over end in order to be conveniently stored and transported. The ramps portability and easy stow ability ultimately, is what makes this design a success. It falls short in the fact that the design requires a significant amount of space once set up. This design is good to look at because it shows a very convent way to design a ramp that is able to be moved around with relative ease. With a few modifications for today’s current guidelines it could be a feasible method adaptable to our ramp design. The key changes that would have to be made would include an addition of a hand rail, increase in the toe kick, and for the particular design constraints in hand it would have to be able to reduce in length. The reduction in length could be obtained by creating landings in which the ramp could alternate direction ultimately reducing its overall length. Another thought that has to be taken away from this design is the footings of the ramp. In this design the footings and the legs that they support come down to a rather aggressive v shaped point which could cause problems in softer ground. To solve this either a redesign to a flatter point could be made or another option would be to add an additional toe plate to increase the surface area to the ground.

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5. Patent Number US20030213072A1: Portable Ramp and Load Support Assembly

With portability at the forefront of innovation for the band shell accessibility ramp, information was accumulated in regards to products on the market that achieve similar design considerations. A patent search yielded the Portable Ramp and Load Support Assembly design patent, which brought a sturdy, lightweight, durable ramp device focused on easy storability in SUVs, pickups, and RVs [1]. Although designed primarily for large animals, the ramp itself hit many of the criteria created during the design of the band shell accessibility ramp.  The device is assembled as two separate ramps that are connected and folded through the use of a pivot pin.  The ramp itself is made from a durable yet lightweight injection molded plastic and utilizes a slip resistant platform. To provide the ultimate amount of uses for the ramp, there are many interchangeable connections to suit different uses. These connections include a float to allow the ramp to be used in water applications, removable legs to turn the ramp into a table, and wheels and pull handles to easily move the ramp to multiple locations.

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There are a few different aspects of this design that may be useful for the band shell accessibility ramp, the first of which are removable legs. Due to the fact that the ramp is not limited to only one transportation height, removing the legs will allow for signification weight reduction to each section of ramp. For a certain application, only one section may be needed, so the legs could be removed prior to transportation. Another aspect of the patented ramp that could be applicable to the band shell ramp design is interchangeability. The addition of wheels and pull handles could significantly reduce transportation efforts and time associated with moving the ramp from the trailer to the final location.

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Journal Papers

1. "Consequences of a Cross Slope on Wheelchair"

With the band shell accessibility ramp primarily being used in outdoor locations, it is important to consider various slope conditions the ramp may be subjected to. Cross slope is a slope gradient in the transverse direction of the ramps intended slope. Many public parks and other grass/dirt locations that the ramp will be used in may not be precisely level, which gives the chance for a cross slope on the ramp to form. A study was done by Handrim Biomechanics which looked at the effects of cross slope on wheelchair users. Tests were done on subjects at both a 3° and 6° cross slope [2]. Their results were conclusive in areas to be considered in the band shell ramp design.

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Handrim Biomechanics observed that the speed of ascent by the wheelchair users was not affected by cross slope. Level change speed was an important factor set by the group when designing the ramp. This is due to scenarios such as if an individual in a wheelchair would need to go up on stage quickly to present or accept an award. It is good to know that various topographic conditions will not affect ascent time.  Although ascent time was not affected, both the power required to ascend and the amount of pushes to reach a certain height increased. In fact, the power required for propulsion on the 6° cross slope more than doubled. This in turn will fatigue the user much more if a cross slope is present. This information will be useful while writing an operation manual for the ramp. If a cross slope is avoidable by positioning the band shell in a certain orientation, it should be advised that this would be preferable for wheelchair ramp operation. Although ascent will be harder with a cross slope, it is still within reason to operate the ramp, however steps should be made to mitigate them when possible.

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Source: Richter W.M., Rodriguez R., Woods K. R., Axelson P.W., 2007, “Consequences of a Cross Slope on Wheelchair,” Handrim Biomechanics, 88(1), pp. 76-80.

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2. "Wheelchair Ramp Navigation in Snow and Ice-Grit Conditions"

In the article written by Edward Lemaire, the effects of pitch and surface conditions on manual propulsion wheelchairs is examined. This cross-sectional study included 11 different subjects of varying age, ability, sex, wheelchair type, and tire type. The study was conducted in controlled conditions where the subjects were asked to ascend and descend ramps of 1:10, a 1:12, and 1:16 pitch. The ramps were subject to snow and ice, in separate tests. The subjects rated their experience with five reactions: Very Easy, Easy, Moderate, Difficult, and Very Difficult. The 1:12 grade proved to be moderate to difficult for the subjects to ascend, and moderate to descend in the snow. The ice did not pose much of a challenge at that pitch, but there is a noticeable increase in difficulty when the pitch is increased. This study provides some insight on the decisions we have previously made regarding the pitch of our ramp prototype. Since the ramp is for use through the city of Buffalo, the possibility of snow and ice is very realistic if the stage is used during the winter months. From the conclusions from this study, the 1:12 pitch of our ramp would likely be acceptable for use during the winter months, but having handrails and non-slip surfaces would be a must; both elements we have included in our designs.

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Source: E. D. Lemaire, P. A. O'neill, M. M. Desrosiers, and D. G. Robertson, “Wheelchair Ramp Navigation in Snow and Ice-Grit Conditions,” Archives of Physical Medicine and Rehabilitation, vol. 91, no. 10, pp. 1516–1523, 2010.

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3. "A Kinetic Analysis of Manual Wheelchair Propulsion During Start-Up on Select Indoor and Outdoor Surfaces"

The main objective of the study, was to determine how different surface conditions effect the start-up propulsion of a wheel chair. In other words, it examines the relative ease (in terms of pushing power) of traversing certain ground (or floor) surface conditions. The researchers found that the surface conditions did not matter much once the user was moving. Where the surface conditions matter, is during start-up. They found that interlocking pavers, long carpet, grass, and ramps were much more difficult for the user to navigate and required much more torque then for short carpet, tile, or concrete. The engagement between the user and surface as well as the flatness of the surface are important things to consider.

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This is an important study for the project team to consider because it shows the importance of applying some sort of non-slip surface to our ramp design. The data that the researchers obtained shows that the ramp tests consistently showed the highest torque per push for the user. Since our design is made out of aluminum, wheel slip could become a significant issue due to the high torque and smooth surface. Based on the data and intuitively, the user will be able to travel further per push on a surface with high amounts of grip since wheel slip will be at a minimum. Ease of use is of a paramount importance to the user so the ramps surface should be as easy to navigate as possible. If the ramp surface is too steep or if the surface properties are not sufficient, the user could get stuck while traveling up the ramp. This would be incredibly dangerous because they would have to then move backwards until they reached a place that they could turn around. This paper clearly demonstrates the importance of surface conditions on wheelchair propulsion and ease of use.

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Source: Koontz, A., Cooper, R., Boninger, M., Yang, Y., Impink, B., & Van Der Woude, L., 2005, “A Kinetic Analysis of Manual Wheelchair Propulsion During Start-up on Select Indoor and Outdoor Surfaces,” Journal Of Rehabilitation Research & Development, 42(4), pp. 447-458.

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4. "A Critical Analysis of the Usability and Design of Aluminium Wheelchair Ramps"

Wheel chair ramps in general must abide by a set of standards set forth by the Americans with Disabilities act. This sets a curtain set of constraints on a wheelchair ramp such as, no more than a 12:1 incline with a 2 degree offset. Designing a portable wheel chair ramp requires a curtain set of requirements that also applies even more contains. This is of course dependent on the application but in general a portable wheelchair ramp must also be light and easily assembled. If looking for a light weight, strong material aluminum is your number one choice. Portable aluminum wheelchair ramps require a set of restraints set forth by the ADA. One restraint that can cause issues for operation on the ramp is the edge protection. It is required to have a 2-inch edge on the ramp to prevent slipping off the edge however this can be designed poorly. If the ramp is built at minim width a manual wheelchair will catch the edge and get stuck so, it is important to design a ramp wide enough to accommodate this problem. Likewise, the handrails required on the ramp must be wide enough to accommodate the width of the wheelchair plus room for hands to push the chair up on the sides. The entry to an aluminum ramp can also cause some problems to the user because the plate being used is usually rather small in length leading to a rather large bump to start. This can be easily resolved by increasing the length of an entry piece to reduce the impact on the user. These issues listed above are all results of doing the minimum specifications by the ADA by simply increasing a few areas of design a proper well working ramps can be designed.

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Source: I. B. Zackowitz, A. G. Vredenburgh, and A. Hedge, “A Critical Analysis of the Usability and Design of Aluminum Wheelchair Ramps,” Proceedings of the Human Factors and Ergonomics Society Annual Meeting, vol. 49, no. 8, pp. 803–807, Jan. 2005.

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5. "Evaluation of Wheelchair User's Perceived Sidewalk and Ramp Slope: Effort and Accessibility"

The journal documents a study done in San Diego on the perceived difference between running and close slope changes on both walkways and ramps. In the United States all public building must abide by the Americans with disabilities act. The act sets specific maximum slopes for both ramps and sidewalks. For ramps the maximum running slope is 8.33% while the maximum cross slope is 2%. For sidewalks the maximum running slope is 5% while the maximum cross slope is 2%. The journal suggests that there was little research done to support these values put in place. The purpose of this study was to evaluate the practicality of the guidelines set in place twenty years before this journal. The study used paid participants both disabled and not disabled to represent new wheelchair users. Both manual and power wheelchairs were used in the study. Seventy nine participants were used and each completed eight trials. The testing involved separately increasing the cross slope (2%-8%) with constant running slope of (2%) and then increasing the running slope (2%-8%) with constant cross slope (2%). The slope of the ramp was changed by using specially made wooden blocks to exactly change the height of the ramp to a pre calculated value. The accuracy of the slopes was within 0.1%. Each participant was asked to first go up the ramp to a flat section then turn around 360 degrees and return down the ramp without the assistance of handrails. The participants were then asked to rank the degree of difficulty on a scale from 1 to 15 and to guess both the slopes. The results of the study were interesting in that the participants were almost unable to detect any sort of difference in slope below 7% and even when put on the 8% slope they said it was too easy. Some participants were quoted as saying “where are the real slopes”. It was concluded that the maximum slopes set up by the ADA were too low and participants could easily handle much steeper grades. Unfortunately this does not mean our team can design our ramp for a steeper grade. We still have to abide by the ADA guidelines. However this does give us confidence in the 12:1 ratio we already designed our ramp with. Users of our product will easily be able to negotiate this slope unassisted.

 

Source: Vredenburgh, A. G. , Hedge, A., Zackowitz, I. B., Welner, J. M., 2009, “Evaluation of Wheelchair Users’ Perceived Sidewalk and Ramp Slope: Effort and Accessibility,”  Locke Science Publishing Company, Inc., pp. 1-15.