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Raks the German Shepherd
and his Wheelchair by Richard Bergins *Article reprinted from: http://www.handicappedpets.com/Articles/bergins/index.htm Initial Contact In July 2004 I contacted a woman named Svetlana regarding
an ad I saw about her needing a cart for their disabled male German Shepherd on HandicappedPets.com. She told me her dog named
Raks was 10 years old and was diagnosed some months ago with six age-related degenerated discs in his mid-back. She currently
was walking him with the help of a lifting harness she made herself out of a dog seatbelt. She noted Raks weighed 105 lbs.
with much energy and strength, so the combination of Svetlana holding Raks’ walking sling with one arm and trying to
control him with the other arm was quite exhausting and probably not good on her back!
Raks before his cart
 She lived only 30 miles
away so we were able to set up a meeting and measuring session. Upon taking my eight or so measurements, Svetlana and I spoke
about Raks’ diagnosis, his activity level, the environment they take their walks, bladder and bowel control. Armed with my measurements, some photos, and agreed upon requirements, I was ready
to build! Of course I first had to design a cart to fit this large dog, based on my previous cart designs. DesignI like to work in AutoCAD,
which is a CAD program allowing me to draw everything to scale and easily make changes on the computer. CAD stands for Computer-Aided
Design. I have my own licensed “light” version of AutoCAD. Utilizing
this program I am able to get a tracing of the dog into my drawing, and then build a cart to fit him. I of course allow for
some adjustment because projects rarely fit perfectly without some fine-tuning. My design utilizes square aluminum tubing and polycarbonate plastic plate for the main frame. I chose the larger
diameter wheels because Raks is a big dog and he also goes over terrain with bumps and obstacles sometimes. The larger diameter
wheels roll over obstacles better and have some shock absorption with their pneumatic (air-filled) tires. I use nylon webbing strap material to form a saddle, which is looped through slots in the cart’s
side plates up top, and heavily padded with rubber tube covered with thick foam padding. I use buckles to allow for strap
adjustment. My new design has a cover over the padding to allow for
washing and less slippage of padding on the straps. The saddle is
one of the most challenging parts of the cart for me. Like the seating system on a person’s wheelchair, it is the crucial
part that comes into contact with the body and holds the dog in what should be an ideal position. As with human wheelchairs,
incorrect positioning can lead to possible injury and worsening of the current condition. That’s the last thing one
wants to do while trying to help a dog! Sometimes an ill fitting
cart or saddle will just be uncomfortable for the dog, resulting in disuse of the cart. I like to rely on the owner, along
with my observation, as to whether the dog seems comfortable and natural in the cart. They can see the subtle signs and they
know their dog better than I do. After much cutting, drilling and
running back and forth to Home Depot a few times, the cart was ready for Raks to try it out!
Finished Cart- Shown Without Dog
 First Trial Svetlana
was nice enough to come to my house with Raks and her young daughter, who kept herself entertained watching my turtles and
wandering around the garden, it being a nice summer day. Two major obstacles were readily apparent and would need modifications
before delivery of the cart: - Raks was tipping the cart over sideways as he sped around turns, despite my thinking it was wide and stable enough!
- There was not enough clearance to allow Raks
full range of motion for his rear legs, as his legs hit a frame cross-piece on the rearward phase of his leg swing.
To address these issues, I installed longer
axles making for a wider “base.” I also angled the axles ever so slightly, so as to tilt the wheels inward, referred
to as camber. You’ll see many cart makers that do this, and wheelchairs for people too. It allows one to provide a wider
base without going to extremes on axle length or widening the frame. To address Item 2, I simply moved the rear cross-pieces upward. The frame seemed to maintain its stiffness while
allowing lots of free space underneath for his leg swing. Second
Trial Once again, my ever-so-patient
client, dog and daughter made the half-hour trip down to the house on another nice sunny day, all of us hoping Raks would
be walking in his cart soon. Svetlana
brought Raks out of the car, him pulling and barking, all excited and full of energy as usual! The cart was positioned just
behind him, while his legs were lifted into and through the saddle until his thighs were held snug, but not too tight. The
front straps were looped around his chest and just behind his neck, and he was ready to go. We headed for the lake just a
block away, which has a smooth dirt trail around it. Raks was walking, then he was running, then he was chasing garbage and
sniffing everything and pulling, just like his usual self, according to his owner! I took my camera and enjoyed the most satisfying part of building dog carts; seeing
a dog walk and play again! Raks came back with us and he was worn out, just wanted to lie down and drink his water. It must
have been like an athlete who hasn’t run in months; the mind is willing but the body needs time to adjust.
Raks trying out his new cart!
 Fine Tuning We
noticed a little too much weight being put on Raks’ front legs and collar strap. Moving the position of the rear wheels
forward to get more weight onto the cart did the trick. This adjustment was simple, as I include several mounting holes in
the frame. Raks was also tough on the nylon clasps that hold the straps
that secure him in the cart. He was pulling them out no matter how hard we tried to fasten them! I ordered steel ones with
a much better grip and switched out the plastic ones. Concluding
Notes Raks is still using his carts
for his walks. His health seems to have improved in the several months since I saw him last. This could be due to some changes
in medications he has had, his owner trying some natural non-prescription remedies with him. I would hope his health was also
enhanced by his being able to take longer walks and getting regular exercise. I have since provided Raks’ chair with axles that allow removal of the wheels
for easier transport in their car. Svetlana works with me and provides great suggestions and feedback on improving this design. It’s satisfying to combine my work experience
in manufacturing and design and my education (Mechanical and Biomedical Engineering) and apply it to my love of animals. Although
the financial payback right now is minimal, it’s great to hear from an owner, “Thanks for helping Raks walk again.”
Some things need not be measured in dollars! (Contact Rich if you would like him to build a (low-cost) cart for your pet.) "Rich graduated with a BS in Mechanical
Engineering Technology from Penn State University (1985), then moved to the SF Bay Area and worked in manufacturing and design
for several years. He then returned to school to get his MS in Biomedical Engineering from California State University
in Sacramento (1997). He currently works with assistive technology for an agency in central NJ that serves children and
adults with various disabilities. In his spare time Rich has been designing dog cart-wheelchairs, combining his
engineering background with his love of animals. "
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