Yorkshire spacers are a folded tinplate clip that can be applied to plain sided bee hive frames in order to control the spacing of theframes. To the best of my knowledge they have only been made in narrow size.
This alternative to the metal end can be used on any part of frame woodwork that is nominally 22 mm in width. Bending the angled wings outwards slightly also gives the possibility of using on 25 mm or 28 mm woodwork.
I have seen Yorkshire spacers used in many different ways, the drawings show some of these. I have never used any myself and can only judge their popularity by the numbers that I used to sell... I would say that Yorkshire spacers accounted for a good deal less than one percent of sales of frame spacing items. Plastic ends were the biggest seller and the ratio of sales of plastic ends to Yorkshire spacers would have been around a hundred to one.
Yorkshire spacers are fixed by pressing the pointed tabs that face inwards into the wood of the frame part. The tabs are formed at the places where the triangular voids occur in the outer strap of the spacer.
One of the ways that I have seen them used is not illustrated... In some boxes that contained many Abbott type frames there were several plain DN/1 frames that had the spacing maintained by the addition of Yorkshire spacers to the top bars so that the spacers matched the fat portions of the Abbott bars.
Stability while in transit can be enhanced by using two sets of spacers as the drawing shows, as the lower set avoid any swinging of frames. Another method not illustrated is where plastic or metal ends are used in a conventional way on the frame lugs and Yorkshire spacers are used at the lower end of the side bars, but care has to be taken to ensure that the spacing provided by the two types of spacer is identical.
My experiences may be why Yorkshire spacers aren't popular.