Oct 272016

(posted by Paula Allchin)


Colin Knight (Southampton group) has a client with MS, limited mobility and little strength in her arms. She has a large electric mobility scooter and a helping dog which likes to chase tennis balls for exercise. He is trying to make a device to throw a tennis ball about ten to twenty yards and after firing will “re-cock” itself electrically from the 12volt scooter supply. Needs to be fairly compact to mount on the scooter. There is a device called “Go Dog G4” but it is very bulky.




  12 Responses to “Ball thrower for dog with electric assistance”

  1. As an electric motor to wind up the spring would be quite expensive, possible large and awkward, and difficult to protect from the weather, could we use the motor for propelling the wheel chair to wind up the spring?

    This could be done in at least two ways. One is simply to arrange for a rope to be tied to a tree and the other end loop over a hook on the catapult. If the user drives away from the tree it would pull back the catapult. It would then need a release mechanism or else be arranged so that the catapult tilted and the rope would be released by virtue of the change of angle of the hook.

    The alternative would be to fix a drum to a wheel and wind up by putting the rope round the drum.

    Hope this is of some interest.

  2. Colin,

    Are you sure the scooter is 12V? Most are 24VDC.

  3. From Jill Brown in Salisbury

    I am in a similar situation to this client and have very little movement in both shoulders. I also have an assistance dog who loves chasing balls. I found a ball “chucker ” in our local pet shop. There are two sizes and you need to flick the ball rather than try to throw – I find the smaller chucker much easier to flick.

    My dog will put the ball back in the chucker- that may need some training.

    I hope that helps- if you need further help, do ask.

  4. Further to my previous comment, I have located the REMAP publication, no reference but from about 2011. The Panel appears to have been Hertfordshire South with Brian Bloomfield as the member responsible.

    • It was Brian and South Herts, a motorised version wasn’t needed for that client but if needed a battery electric drill can clamped to the table to provide the “winch” to pull the launcher down until it engages with the catch. Adam has lots of pictures of the manual version.

  5. There is an example of such a launcher attached to a wheelchair in recent REMAP publicity material. The Client’s name was Karen and her dog had been supplied by Canine Partners. Perhaps, Head Office could locate the material and a reference to the Panel that supplied it.

  6. I just found this which uses the wheel idea and would seem ideal:



  7. A common way to launch balls is to have two rapidly contra-rotating wheels, the ball is then dropped between them:


    This simple design just gives the ball a good kick:


    This sort of idea would work but could be a bit costly:


    Other than that get to the local tackle shop and look at ground bait catapults, they would “just” need a motorised drawing and release system.

    Graham (Oxfordshire Remap)

  8. How about a launcher powered by gas (CO2) using soda syphon bulbs from Amazon etc

  9. Perhaps a rubber-powered catapult would be the simplest and most compact solution? Would consist of launch tube with elevation/range adjustment, retain/release sear and trigger, geared motor/drum for rewind and appropriate limit switches. (see cross-bows).
    Regards – Patrick Wormell (Swindon Remap)

  10. I liked this solution. There’s not much technical detail but there may be enough there for some ideas. https://www.youtube.com/watch?v=4PcL6-mjRNk


  11. As you have found, the commercial launchers sit on the ground with a bowl for the dog to place the retrieved ball. I suspect that requiring to mount the launcher on the scooter would make the recharging difficult. Googling “dog ball launcher” lists several, including this “Which?” guide: http://doggiefetch.com/. Could the launcher be transported on the scooter and the helping dog trained to place it on the ground for use? Not sure who would then set it off!
    I assume the client has not the strength to cock one of the bazooka-type launchers http://www.amazon.com/BazooK-9-Tennis-Ball-Launcher-Rated/dp/B01721QZDK?tag=fetch02d-20

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