mounted on a shaft 145 the shaft 145 is supported by spaced fixed members 146 and 147 a bracket 148 is secured to arm 149 of the support 140 a cap screw 150 is secured to the member 146 a tension spring 151 is connected to the bracket 148 and to the cap screw 150 in the printing position shown the spring 151 is behind axis 152 of the shaft 145 and urges the support 140 overcenter in a clockwise direction fig6 against an adjustable stop screw 153 fig1 and 9 in a fixed plate 153 39 the adjusted position of the stop screw 153 precisely determines the printing position when the support 190 is overcenter in the other direction as when the support 140 is at or near the home position the position of the support is determined by an adjustable stop screw 154 a bevel gear 155 secured to the vertical shaft 145 meshes with a bevel gear 156 secured to a horizontal shaft 157 also secured to the shaft 157 is a section 158 of a geneva wheel of a geneva mechanism 159 the geneva section 158 has a slot 160 for receiving a pin 161 on a plate 162 the plate 162 a gear 163 and a gear 164 are secured to a shaft 165 the gear 163 is behind the gear 164 and the plate 162 is behind the gear 163 the teeth on the gear 163 extend for 360 degrees however the gear 164 is considered to be a mutilated gear in that its teeth extend for only a portion of a circle as best shown in fig5 the gear 163 is not shown in fig5 for clarity a stepping motor 166 secured to.