Research

U.S. Patent No. 9,180,037 B1 - When a person sustains a lower body injury they are encouraged not to bear weight on the injury limb, allowing for the injury to heal naturally and in the correct position. The leg brace depicted in U.S. Patent No. 9,180,037 B1 is intended to assist in the mobility of someone with a lower body injury without the use of any assistance from their upper body. The main supporting members of the leg brace are two bent bars which mimic the natural bed of the knee. At the top the leg brace is fastened to the thigh on the injured leg using a cushioned pad with three Velcro straps which can be adjusted to any size thigh. Down at the bottom of the leg brace, a U-shaped bar connects the two upper bent bars at the ground level. The connection between the upper bent bars and lower U-shaped bar is accomplished with nut and screws, which can slide up and down in a track for the user’s height adjustment. On the bottom of the U-shaped bar a rubber wrap assists in gripping the walking surface and cushioning the impact of walking. At approximately mid shin level, a soft flexible strap prevents the user shin from swinging freely past the knees normal extended position. This strap can be switched out with a cushion an adjustable Velcro strap to allow the user to have their leg below the knee in a fixed position. The use of this device assists in the mobility of the user by enabling them to use both their hands and arms freely. This patent gives us a good idea for a type of attachment to the leg, along with several adjustment features.

Joel N. Smith, inventor; “Leg Brace.” U.S. Patent No. 9,180,037 B1, issued November 10, 2015.

U.S. 2007/0182116 A1 - This patent design, invented by Nigel Davey, Todd Pollock and Robert Allen, is named a ‘Mobility Scooter.’ It consists of a scooter like design, with a cushioned seat that can be used to rest the customer’s leg on, at a ninety or forty-five-degree angle. The handle bars, similar to a scooter, have breaks that are to be held down by the fingers. Underneath the knee rest, the seat can be adjusted due to the height of the user. The Mobility Scooter is also foldable, making it simple and easy to transport around, whether in a car or a large bag. This design, in the form of a scooter, seems much more efficient than using crutches. Crutches require a lot of upper body strength in order to swing the body’s weight. It also causes soreness and pain in the armpit and shoulder area. The Mobility Scooter would help the customer get around faster and without so much strain on the body. The scooter also allows the customer to get around easier since they will not have to swing their weight around. However, one negative of the scooter would be that there would be a lot of strain on the knee, which would definitely cause the customer pain. The knee rest in this patent seems to be a bit more comfortable than the final design that the WalkOn! group had. The cushion creates curvature for the knee to rest comfortably. This patent can definitely help the team reconsider the knee rest design. Whether it is the shape of the knee rest or the material, a re-design of the knee rest is beneficial.

Davey, Nigel M. and Pollock, Todd E. and Allen, Robert L., 2007, “Mobility Scooter.” US 2007/0182116 A1

US D516,800 - The US Design Patent by inventor Kenneth R. Bacon introduces the classic ornamental design for a crutch with slight modifications to be implemented. It appears this crutch allows for a patient to rest his/her knee on the design apparatus attached to the crutch. This design effectively eliminates the need for a second crutch, since the injured leg is to be suspended in air. The knee rest does not appear to have and user-friendly modifications in place that would allow for the bent leg to be relieved from its position without stopping use of the crutch entirely. The WalkOn! group currently has a knee rest implemented in the final design from the previous semester. However, after review of this patent, it is evident that our design is flawed in its shape. The knee rest currently in place is simply a flat plate. The patent in review uses a curved plate which would be more comfortable for the user. Although our knee plate is optional, unlike that in Bacon’s design, we could perhaps make it both optional and comfortable with a change of material or shape. Some preliminary ideas that come to mind would involve a pivoted curved knee rest, that could be set into place at the will of the user, without the need to stop and remove the crutch entirely. A change of material would also be feasible, in which case a cloth or plastic strap would fulfill the function just fine.

Bacon, K. (2018). Crutch Apparatus. US D516,800

US Patent Number US20090229- This patent, invented by S. S. Ramm, J. N. Smith, and J. Cardinali, is a “Leg Supporting Crutch System” which supports the weight of the user in the same manner as a traditional crutch, however there are two major differences. One difference being that there is an adjustable leg support which supports the users leg at a 90° angle, and the other being that the design has the capability to use the elbow as a stabilizing point freeing the user’s hands. Although, the concept of the elbow stabilizing point does successfully free the user’s hands while stationary, it does not free their hand while walking. On the other hand, the adjustable leg support incorporated in the design contained within this patent is a rather intriguing feature of the design. When using a crutch to ensure the injured leg does not come in contact the user is forced to place their leg in an unnatural position causing discomfort. By incorporating the leg support in our design we will provide a feature which allows the user to rest their leg comfortably at a 90° angle, if desired, without any strain on the user’s muscles or body.

S. S. Ramm, J. N. Smith, and J. Cardinali, “Leg Supporting Crutch System,” US 20090229643A1, 17-Sep-2009.

US Patent Number 7,434,592 B2 – This patent is very similar to the generic crutch that has been used for a few millennia, the difference being a few ergonomic enhancements to fix some common problems. A main argument against under-the-arm crutches is that they can oftentimes lead to unforeseen arm and upper body damage due to pressure on the nerves at the upper arm. The crutch in this patent has one main supporting arm in place of two, as it has capabilities to be folded for easier storage. The cushion pads for the under-arm and the palm are interchangeable, and can be contoured to comfortably fit the user, without putting the dangerous pressure on their nerve in the axilla. A shock absorber is placed on the distal end of the crutch to take force away from each motion, as well as retain the ability to help propel the user forward while walking. The distal end of the crutch also has a gripping pad on the bottom to firmly hold on various surfaces. This pad has the ability to angulate in order to keep full contact with the ground throughout the range of motion of the user. An alignment rib connects the supporting member to the adjustable portion to provide support, lengthening, and collapsibility. The crutch is collapsible to approximately half of its length to allow for ease of transportation and storage. This design shows how ergonomic, simple fixes can drastically improve upon a piece of equipment that has been so similar for so long. Since our design takes the weight completely off of the upper body, the nerves in the arm will not be affected and there is much less chance of unforeseen injury.

Larson, Brad and Lester, Ken. “Ergonomic Collapsible Crutch”. U.S. Patent No. 7,434,592 B2. October 14, 2008.

The use of a Hands-Free Crutch in Patients with Musculoskeletal Injuries: Randomized Control Trial - The crutch seen in Egyptian paintings dated back to 2830 BC. A crutch enables a person you still be mobile while keeping weight off an injured limb. A traditional crutch is still the most commonly used and economical means of assistance. Unfortunately, when sometimes an injury occurs to a part of the lower body there is also an injury to the upper body as well. These injuries to the upper body do not make it possible to use your hands, arms or shoulders in order to hold or position a crutch. These injuries can often render a person bed ridden or wheel chair ridden until such a time when their lower body injury is healed enough for weight bearing. With traditional crutches, other problems such as shoulder dislocation, carpal tunnel and under arm sores can occur. In this trial the hands free crutch used was attached to the thigh using Velcro straps and was bearing the body at the knee of the injury leg. The frame was constructed from a lightweight carbon fiber. All of the 40 patients said the hands free crutch was easy to learn and use. The hand-free crutch reduced the average in-patient stay from 6.7 days down to 2.3. After discharge, the crutch was used for an average of 3.5 weeks. Only five patients reported problems with using the hands free crutch. Three of these cases were soreness in the knee and two complained of backaches. The extents of these trials were unable to determine if soft tissue injuries were possible for extended duration usage. The hands free crutch provides a far greater degree of freedom when compared with a traditional crutch. By using this trial, we see that a hands free crutch that uses the knee as a means of weight bearing is feasible and has minimal negative side effects on the user.

Rambani, Shahid and Goyal. “The use of a Hands-Free Crutch in Patients with Musculoskeletal Injuries: Randomized Control Trial.” International Journal of Rehabilitation Research Vol. 30 (2007): pp. 357-359.

Experimental Characterization of Auxillary/Underarm Interface Pressure in Swing-Through Crutch Walking - A crutch is used to allow a patient to move around and go about their day, even though they have lower body injuries. Unfortunately, as emphasized in this journal article, crutches put a lot of strain on the armpit area, which ends in causing pain and damage to the axillary nerve. This was taken into account when the final design was created. It is hands free, which means that it will not include any force, that would cause injury, in the axillary nerve. This journal article supports the final design we have come up with, since we do not have any force acting on the axillary nerve. The journal included a study. The subjects used were eight nondisabled college students who never had any shoulder damage. These college students were given axillary crutches and they used them until they were able to be comfortable with them. The forces on the axillary supports were measured with an F-sensor. The F-sensor takes measurements of forces and they are used to calculate the total force as well as the contact area. The sensors were calibrated before each use. At the end of the experiment, the volunteers were asked to rate the ease and steadiness of the axillary crutch.

Borrelli, James and Haslach Jr., Henry W. “Experimental characterization of axillary/underarm interface pressure in swing-through crutch walking.” Journal of Rehabilitation Research & Development Vol. 50 No. 3 (2013): pp. 423+. DOI 10.1682

Identification of Axillary Crutch Length Estimate that Best Predicts the Ideal Axillary Crutch Length in Apparently Healthy Individuals - An important decision to be made when designing an axillary crutch is the length of the crutch. Improper length with respect to the user may result in musculoskeletal disorders. A Journal by authors Odebiyi, Adeagbo, and Awe studied estimation techniques to determine the best crutch length. Using a study of 250 apparently healthy patients, they performed a study testing different methods of crutch length estimation such as the arm-span technique. The results of this study showed that the Foot- anterior axillary fold techniques were the best predictor of the ideal axillary crutch length. This journal performed statistical analysis of the crutch lengths which can be used to implement an adjustable length setting for the crutch being designed in group WalkOn! The adjustable length must be within a range defined by the results of the study and the data gathered. This will save the team time and money in designing the product as we can refer to this data to determine the appropriate range to implement and the position along the crutch where it is to be located.

Odebiyi, Daniel O., Adeagbo, Caleb A. and Awe, Gboyega A. “Identification of Axillary Crutch Length Estimate that Best Predicts the Ideal Axillary Crutch Length in Apparently Healthy Individuals.” Journal of Prosthetics and Orthotics Vol 28 No. 1 (2016) pp. 38-43. DOI 10.1097

Design and validation of GCH System 1.0 which measures the weight-bearing exerted on forearm crutches during aided gait- The article by Gema Chamorro Moriana, Jesús Rebollo Roldán, José Jesús Jiménez Rejano, Raquel Chillón Martínez and Carmen Suárez Serrano provides insight on the proper way to perform failure analysis on our product. In the results section of this article it is shown that the maximum force exerted on the assistive walking device was 31 kilograms of force exerted vertically on both the load bearing surface and the surface which comes into contact with the floor. However, the crutch used in this experiment is not a hands free assistive walking device, and this could affect the results directly. For this reason, it would be beneficial to the development of our product to create a full scale prototype of the walking device and use the methods disclosed in this article to obtain an accurate measurement for the types of forces which will be exerted on the assistive walking device. After obtaining this information the effectiveness of the new system can be determined with the help of computerized FEA analysis.

G. C. Moriana, J. R. Roldán, J. J. J. Rejano, R. C. Martínez, and C. S. Serrano, “Design and validation of GCH System 1.0 which measures the weight-bearing exerted on forearm crutches during aided gait,” Gait & Posture, vol. 37, no. 4, pp. 564–569, Apr. 2013.

Effects of spring-loaded crutches on gastrocnemius activity and upward displacement of the body during gait – This study focuses on the impact that a spring assisted crutch can have on reducing the stress experienced by the gastrocnemius muscle during crutch gait. The study, using 12 healthy males, had the subjects perform crutch gait utilizing spring-loaded crutches and axillary crutches. The activity of the gastrocnemius muscle was measure using a wireless electromyography system, and the upward displacement of the body during gait was measured using a three dimensional motion capture system. The study concluded that the spring-assisted crutch drastically reduced the stress experienced by the gastrocnemius muscle during gait. The gastrocnemius activity significantly lower but the upward displacement of the body was significantly greater than the gait of the axillary crutch. Research has suggested that minimal displacement of the center of mass with selective muscle control is important for efficient gait. This information allows our team to look into using a spring assisted system, weighing the benefits of the spring assist with the benefits of other designs. Walking using a spring assist may be uncomfortable in certain crutch configurations, and that is something to take into account as customer comfort and satisfaction is a top priority for any product.

Kang, Min-Hyeok and Oh, Jae-Seop. “Effects of spring-loaded crutches on gastrocnemius activity and upward displacement of the body during gait”. The Journal of Physical Therapy Science. Vol 28, No. 8 (2016): pp. 2347-2349. https://www.jstage.jst.go.jp/article/jpts/28/8/28_jpts-2016-275/_pdf/-char/en