The trade union badge has been an important symbol of solidarity since the 19th century. The art of badgemaking has flourished since then.
We often use the templates of computers to make tin button round badges but for many years the pride in union membership and collective action has been displayed by high quality design and production of lapel pins and badges.
The Eight Hour Day Committee badges were exemplars of this art.
A relatively simple form of this was the round medal illustrated here. The hands have been a constant in union banners and badges symbolising strength in unity.
The eight-hour committee membership was an honour and the elaborateness of the lapel pins was an expression of this. Committee members were easily identifiable by the ribbon and medal.
The badge and rosette/ribbon seem to date, in Britain at least, from the 1700s according to Paul Martin in The Trade Union Badge (Ashgate, 2002) with the ribbon/rosette getting bigger depending on your position in the parade! The holes in these badges were attached to a ribbon and crossbar.