Electric grabber

Project  / Project number: BK2018/89  /  Status:

The challenge


Zoe enjoying her new grabber

Zoe required a grabber to be able to pick things up from the floor or other places.  The grabber had to be able to grasp large items, such as her teddy bear, as well as small items, such as pencils. Various commercially available grabbers had been tried, but she did not have the strength to pull their actuators or to maintain the pressure while the object was picked up.  Some grabbers had a lever to lock the jaws, but she struggled to operate the actuator and the locking lever at the same time.


The solution

A grabber was made using a motorised claw from a toy robotic arm.  The only control was a centre-biased lever switch mounted just under the handle.  Pushing the switch one way closed the claw, the other way opened it.  With no pressure on the switch, the claw stayed in its last position.  She could now operate the switch to grab the item and then use both hands to pull the item up to her level.  Velcro bands on the stem and a Velcro strip on the arm of the wheelchair allowed for stowing while not in use.

The claw was powered by a built-in power block of the type used for “on the go” mobile phone charging.  This device could be re-charged from any mobile phone charger and switched itself off automatically when not in use.

Some plastic parts of the claw were replaced by stronger aluminium parts to improve robustness.

See a similar design.

These rechargeable batteries are very useful and have been appearing recently in other Remap jobs, but some thought should be given to safety if they are not being used for the manufacturer’s intended purpose of charging mobile phones.  Two safety checks were made in this case.  The maximum current taken by the claw with the motor in the stall condition was measured at 700mA.  The stated maximum output current of the power block was 1000mA.  A check was also made to see what would happen if a short circuit developed in the wiring or in the claw itself.  Under short circuit conditions, the power block behaved perfectly by instantly switching itself off.

The BBC TV broadcast this interview with the client.

The benefit

Zoe is more independent now that she can pick up items herself.

9 thoughts on "Electric grabber"

  1. Peter Rowe says:

    A friend of mine had a brain tumor and now has very weak arms as well as quadraplegia. How could such a grabber be made available to him?

    Thank you

    1. Ron says:

      This is fantastic and theres a huge market for better grabbers than the of the shelf garbage that’s currently available im currently looking at making similar as i have a muscle disease and poor grip strength as do tens of thousands of others. We know what we need and you cant by it. So good to see someone thinking and listening to the real needs

      Congratulations regards Ron

  2. Sophie Morrison says:

    Hi Peter,

    If, like Zoe, your friend isn’t able to manage any of the commercially available reachers, Remap can provide him with one. He’d first need to get in touch with his local group, which you can look up online at http://www.remap.org.uk/contact-remap Alternatively, you can call the office on 01732 760209 or email data@remap.org.uk and we’ll put you in touch with the right person.

  3. Ayesha Mark says:

    This gadget works wonderfully with an electric powerchair and I would like to buy it.

  4. Robert Monk says:

    Ayesha, Remap is not a commercial organisation; we make our bespoke aids free to the individual user. More about us is available here: http://www.remap.org.uk .
    It appears you are intending to sell on the item. If this is not so and you are enquiring for yourself, then please check that you aren’t able to manage any of the commercially available reachers. If not, then Remap can provide you with one. You first need to get in touch with your local Remap group, which you can look up online at http://www.remap.org.uk/contact-remap . Alternatively, you can call the office on 01732 760209 or email data@remap.org.uk and we’ll put you in touch with the right person.

  5. John D says:

    What type of motive device did you use. A solenoid or gear motor ?
    Also a reverse polarity switch had to be used. What type of switch did you use.
    John D

  6. Geoff H says:

    Hi John,

    I used the Makeblock 86502 which has a motor/lead screw/nut arrangement to operate the claw.


    The switch was from RS (part number 1232420). I had to make a few modification to the claw to get it to work reliably. If you intend to make one I would be happy to send you details with drawings. It looks as if we are not supposed to publish our email addresses here so maybe you could get that from head office.

  7. Chuck says:

    My wife has a hard time with our present hand scooper claw for dog poop would you have something that is much easier for her and still be able to pick up dog poop thank you

    1. Robert Monk says:

      Thank you for contacting Remap. If you would like one to be made for you and live in the UK, you can make a request here: https://www.remap.org.uk/referral-form/ . But bear in mind that suitable commercial ones may be available to suit your own circumstances and Remap does not make what is commercially available: https://www.remap.org.uk/can-we-help-you/, so please check first.
      If you live outside the UK, it is unlikely we can help directly. If you can find an organisation local to you (for example a technical school, hobbyist engineer, men’s shed, Hackspace or similar) who can make it for you, then we would be happy to assist them.

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