A new type of hat was introduced in England at the end of the eighteenth century. Called a tall or round hat, its circular shape was in contrast to the low triangular tricorn popular in the earlier part of the century.

Yet the new shape presented new challenges, especially with regards to storage and handling, as hats could no longer simply be tucked under an arm. In reaction to such challenges, the first collapsing top hat on record appears in an 1812 English patent submitted by Frances Dollman. In the patent Dollman describes how the hat would be built with an inner ‘elastic steel spring’ which would allow it to be neatly tied for travel.

As this new shape became more popular, it started to replace the chapeau bra or arm hat used at formal and evening events, such as the theatre and balls. This provided its own challenges as the hat took up more space than its predecessor. In 1834 Antoine Gibus applied for a patent in Paris for a ‘chapeau mècaniques’, a fairly simple hinge system that allowed wearer to manually open and close the hat. When closed the hat would become almost flat (brim allowing). 

In 1845 Gabriel Gibus submitted a patent in Paris for an improved mechanism that included a spring. This was the beginning of the ‘chapeau claque’. With this new spring the hat could now be opened quickly with a distinctive snapping sound. The Gibus family continued patenting changes to the collapsible top hat into the 1850s.

What this x-ray reveals is the rarely seen internal spring mechanisms of a collapsible top hat.

The mechanism is created by two metal hoops, one forming the crown of the hat and the other attaching to the brim, separated by four hinged upright supports. Each support features a central hinge, which allows it to fold inwards, as well as an attached short spring that runs parallel from the centre of the hinge to the crown.

When the hat is pushed closed the spring becomes stretched. This tension causes the hat to pop open with a slight pressure to the crown of the hat. Unlike standard top hats the body of the collapsible top hat is made from a soft fabric which allows the hat to fold. When opened the tension between the top and bottom hoop creates the shape of the hat. The fabric can be prone to wrinkling due to folding as seen in the x-rays below.

The collapsible top hat has been known under a variety of names in English throughout its long history; a crush, opera, folding, elastic, and (of course Gibus), hat.

Perhaps due to its ideal marriage of functionality and formality, collapsible top hats were still kept on hand in the UK House of Commons until 1998; members were required to wear a top hat while raising a point of order.