pass through slots 53 for a clutch feed 34 fig5 c and 5d the two throat plates 33 differ in the size or length of a needle pass through opening 55 and or of a code 57 that is printed or stamped on the upper side and or the underside of the throat plate 33 the code 57 can for example be fashioned as a bar code as a number or as a color code and is uniquely assigned to a particular type of throat plate in fig4 a 4d four different types of sewing feet are shown they differ not only in their shape or design but also by a visibly printed or stamped code 57 in the form of a number the code u201c 1 u201d characterizes a back transport foot for useful and decorative stitching code u201c 2 u201d designates an overlock foot code u201c 9 u201d designates a darning foot and code u201c 37 u201d designates a patchwork foot sewing machine elements need not necessarily be characterized with a code if a unique identification is also possible on the basis of other features in fig5 a and 5b the fastening of a sewing foot 21 to.