Santa’s Little Patent

Ah, Christmas; seems like a lifetime ago now. My daughter Ruby asked Santa for a Barbie Dreamhouse, which if you’ve never seen one, is pretty big.  So we needed a trans-shipment point for Santa which meant clearing out the dreaded cupboard under the stairs, where I found this:


Absolutely no idea how this got there, but it’s clearly very old

It’s a pretty simple wee device, and it’s instructions are:


And if you look closely in the top right-hand corner you’ll see:


So I thought (and hope) it might be interesting to take a look at it, and how patents work in general.

A Patent provides the owner (“the Patentee”) with a monopoly over new, non-obvious and industrially applicable inventions for a limited period (up to 20 years from filing, provided annual renewal fees are paid to keep it in force).

The monopoly the Patentee has is defined in the “claims” of the Patent.

Marking the product with the Patent Number is good practice because (a) the Patentee should want to make people aware they have one protecting your invention and it shouldn’t be copied and (b) if the Patentee does not mark the product and an infringer can show they were unaware of the existence of the patent, the Patentee may not get damages or an award of the infringer’s profits, although you should still be able to obtain an injunction/interdict preventing further infringement.  It’s possible to now provide marking by way of a website link.

Even before looking this one up, we can tell it’s pretty old and likely to have expired (both because of the number being prefixed with a “1” and, let’s face it, the state of the packaging).

Granted patents and pending applications over 18 months old are publicly available for viewing – they are not secretive, it’s a right that third parties have to examine patents and review the monopolies that exist.

Checking with the UK Intellectual Property Office’s database we find:


So it was filed just around The Beatles splitting up, and expired just around the time Madchester was taking off.

But what did it cover when it was in force?

Well, let’s find it, and without too much digging:





The Patent specification has a number of different sections: a preamble which sets the scene for the invention, a description which shows how the invention may be put into effect along with some drawings to help in that understanding, and the all important claims which establish the monopoly granted by the Patent.

We can also see that the Applicant (and eventual Patentee) was Martindale Electric Company Limited of London and was invented by Ivor Ernest Davies, who was quite likely an employee.  “Inventor” and “Applicant” are not always one and the same and this is where the issue of “Entitlement” comes in, but we shall leave that for another time.

Claims can be classified in various ways, but a primary consideration is whether they are “independent” (wholly self contained) or “dependent” (refer back to earlier claims and add new technical features). Dependent claims provide fall back positions should independent claims be deemed to be invalid at trial.

So Martindale had granted as their independent claim:

1. Apparatus for testing the connections of a supply system to an electric plug or socket, said apparatus comprising a body having mounted thereon contact pins or sleeves arranged so that they can engage the line, neutral, and earth, contacts respectively of a plug or socket to be tested, the body also containing an electric circuit connected between its pins or sleeves, the circuit having three components which give a visible indication when passing current, there being a conductive path -containing a different one of the components connected across each two of the three pins or sleeves.

So if that described or “read into” a third party’s product, such a product would infringe the Patent in the UK.

Think you have something inventive?  Want to talk about it?  Drop us a line for a no obligation discussion.