The device for assembling a green blank form of the crown of a tire comprises: a support having a shape that exhibits symmetry of revolution (4), —members (8) for shaping the green tire, and for each member, means (20, 35) for removable attachment to the support, comprising at least one bolt (20) and able to fix the member to the support as soon as the member (8) is in a reception position on the support. The bolt (20) has a face able to collaborate with at least one face of the member or of the support in order to place the member in the reception position, the faces being arranged so that the face of the member or of the support cannot move the bolt. The members, when they are in the reception position, are juxtaposed to form a reception surface for components that form the crown of the tire.