In our everyday speech, a Heath Robinson device, machine or affair is anything which is extraordinarily complicated, complex beyond any immediate need or purpose.If someone has proposed a plan which will be expensive and complicated just to achieve some minor objective we may say 'it's a bit Heath Robinson' or 'that's a Heath Robinson approach'
Usually though, it's applied to machinery: 'a Heath Robinson contraption'. It's often applied to emergency repairs, when the proper materials or tools have not been available, and the result looks strange and awkward
but works, somehow, if mysteriously.
Heath Robinson himself started out as humorous illustrator but soon developed a mocking or cynically critical eye.He'd noted that organisations, particularly the army, had a gift for finding,and the money and the resources to waste on, grossly inefficient, often impractical, solutions to problems which were either of their own idle imaginings or real and present but not really important.He teased the army e.g. by suggesting that they could crack nuts by simply deploying two gun crews with facing mortars, the nut being suspended between the mouths of the guns.Well, they had the men doing nothing, they had the time, they had the means, so why not?
The pictures of big machines, enormous contraptions of wires , pulleys and levers appeared quite late in his career but are what made his name.Utterly impractical, wildly complicated but they ought to work as well as the obvious method.

A google search will reveal quite a range of his work. The Wikipedia entry is as good as useless, but if you find the entries under Heath Robinson for Chris Beetles or Liverpool Museums you'll get the idea (you may gather I've despaired of getting the sites to make links on here! Bedstor, where are you?)