​​

Credits

Jeahoon (James) Yun: Intern at PVNet Advanced Technology Center

Pauline Cho: Preliminary Reviewer; Auburn University College of Veterinary Medicine

​

Abstract (11/7/2024)

​

A variety of veterinary orthopedic devices are in use today to help animals in need. Mobility harnesses are used to help animals with partial paralysis of limbs. Besides their primary use to extend their lives, mobility harnesses have evolved in providing more comfort to the animal as well as don-doff ease for the animal owner. However, current mobility harness designs have a deficiency that could benefit from a redesign. A prototype for enhancing user comfort is presented below.

​​​

See figures 1 and 2 below for description and comparison.

​

​​

​

​

​

​

​

​

​

​

​

​

​

​

 

 

 

               Figure 1: Current medical grade harness         Figure 2: Modified harness for more user comfort     

  

​In the current standard harness design [see figure 1.], the two parts of the front harness are separated, with the vertical sling having a different attachment to the frame than the chest strap. In addition, select wheelchairs use a curved metal rod (yoke) that connects to the chest harness which, while providing extra stability to the frame, is inflexible, expensive, adds to the difficulty of placing the dog in the wheelchair, adds stress to the dog and handler, frequently hits the dog’s back when in motion, and adds unnecessary weight to the wheelchair.

In the modified version [See figure 2.], a new strap router that incorporates the vertical and chest harnesses onto one small routing piece is used. This piece is attached onto the front of the horizontal frame rods, allowing a degree of rotation and horizontal adjustability.

When used in conjunction with appropriate elastic straps, the new strap router more closely follows the direction and movement of the dog with greater comfort.

​​

​

​

​

​

​

​

​

​

​

​

 

​Figure 3: 3D model of the strap router mechanism.

​

Each strap router is a single piece, with a large hole going throughout it that slides onto the wheelchair frame. The main body of the strap router would face away from the wheelchair to avoid irritating the dog using it, as seen in figure 2. The inside surface also facilitates adding soft padding between the device and the dog’s body, further reducing irritation.

The strap router has two slots - 1 vertical and 1 horizontal.

The Vertical slot routes the strap which wraps around the belly and back. Tension is adjusted using a buckle. The strap would allow the dog more flexibility, while alleviating the weight that came with the standard design.
The Horizontal slot routes the strap which goes around the chest. On one end of the strap, it wraps around the main body of the piece and is sewn to itself, as shown in figure 2. On the other end, the strap similarly wraps around the piece, and will be connected to itself via a buckle, which will also adjust the tension, which can be seen in figure 4 below.

​​​​

​

​

​

​

​

​

​

​

​

​

​

​

​

​​Figure 4: Working model of the adjustable strap on the modified harness. The strap wraps around the piece and loops through an adjustable buckle.

​

The compact design and ease of use allows for a simpler and more efficient construction of the wheelchair. The strap router is available to the public as a free model that can be 3D printed under creative commons licensing.
The new strap router simplifies both the construction and use of the wheelchair by being compact and easy to understand. It increases the dog’s range of motion with its torso while alleviating some of the weight the dog has to carry around.

 

​Strap Router STL model available at no cost. Send a request to education@pvnet.com with the Subject "Strap Router STL request".

References
Charbonneau, R., Sellen, K., & Seeschaaf Veres, A. (2016). Exploring Downloadable Assistive Technologies Through the Co-fabrication of a 3D Printed Do-It-Yourself (DIY) Dog Wheelchair. Lecture Notes in Computer Science, 242–250. https://doi.org/10.1007/978-3-319-40250-5_24

Peham, C., Limbeck, S., Galla, K., & Bockstahler, B. (2013). Pressure distribution under three different types of harnesses used for guide dogs. The Veterinary Journal, 198(1), e93–e98. 

https://www.sciencedirect.com/science/article/abs/pii/S1090023313004681?via%3Dihub​​

​​​

​

View this video down below to receive a visual representation of how the model actually functions!​​​