Israeli electrical engineer Avraham Hagay wrote into Gizmag this week to tell us about his invention, a motorized shopping trolley designed to make it easier to push a full load of groceries around the store and back to your car. The system, which carries loads of up to 120 kg (265 lbs), can be retrofitted onto existing carts or integrated into new builds. Hagay's currently in talks with local companies and he hopes to soon find a business partner to help manufacture, market, and sell the technology worldwide.
"It all began when I saw old people having difficulty driving the heavy trolley in the super[market]," Hagay tells Gizmag. "I noticed that it is hard also for young women." Hagay researched online and couldn't find any standard shopping carts with motor-assisted drive, so he decided to build one himself.
The first prototype (pictured below) was essentially just an electrical motor that attached to a regular trolley at one of the wheels and the underside of the cart platform. Testing showed it was too heavy and cumbersome for practical use, so Hagay designed a mechanical structure to hold the electrical engine and the wheel. This could replace the existing rear-left wheel. And to it he added a rechargeable battery, control box, and speed throttle.
That second prototype also proved problematic, this time because it accelerated too fast when the trolley is empty. To fix the problem, Hagay added a speed sensor to the wheel structure. The control unit can now adjust the speed to a programmable maximum of 10 km/h (6.2 mph). Hagay says that the speed is usually 3 km/h (1.9 mph), with a linear acceleration below that point.
A speed throttle on one of the hand grips gives you control over the precise speed of the trolley, just like on a motorcycle. Next to the throttle you have a battery power indicator and an on/off switch. The electric trolley runs on two 12V/5Ah batteries connected in serial to reach 24V. Hagay says it should last for 12-13 km (7-8 mi) of travel, which will likely necessitate charging every two days. The battery box can be easily swapped out for another one while it recharges, so the supermarket doesn't have to worry about putting the trolley out of commission for more than a few minutes.
Hagay says that the necessary parts can be retrofitted to existing supermarket trolleys with little difficulty because most supermarkets around the world use the same trolleys and the same type of wheels. That means that most carts will be able to accommodate Hagay's wheel holder structure without modification, and for those that don't the structure could be redesigned to fit the differences.
Hagay has tested his electrical super trolley to rave reception in his local community, and it's been received with enthusiasm by Israeli supermarket companies. "Since I am a private person and still do not have a company, locally in Israel I joined a local super trolley importer," Hagay explains, "and he presented the product to the big local super[market] brand companies."
"They emphasized that every super[market] should have some electric trolleys to serve older people and women, and to support the super[market] workers who arrange the goods on the shelf," he continues.
Hagay has not yet sold his idea or technology to anyone, but he hopes to move forward with it shortly.
How about sealed ball bearings in oversized wheels and a mount design that will not develop woggling or dragging, Simple, passive, cheaper and substantially better than motors and batteries.
You could also go to a slightly larger wheel to overcome resistance or make them easily swappable so the store can more keep them in working order.
Also this: http://i.imgur.com/8aimZiE.jpg
Some people struggle to walk and stuff but I don't think many people need a hand applying the 0.01 lbs of force to get their grocery cart to move slightly forward.