| 摘要 |
899,648. Sewing machines. FORSTER, E., and FORSTER, J., [trading as FORSTER GEB.]. July 14, 1959 [July 15, 1958], No. 24095/59. Class 112 [Also in Group XXIV] A sewing machine including a plurality of cams, a plurality of followers displaceable in fixed guides, and disposed between the cams and a rocker connected to means for effecting the formation of an ornamental seam, has a manually operable pattern selector effecting connection of a selected cam follower or followers with the rocker. Each follower 106 is slidable in a fixed housing 107 and is disposed opposite a corresponding one of a bank of cams 105 and between the cams and a rocker 103 connected at 104 to the devices (not shown) effecting the shape and appearance of the ornamental seam. The selector comprises a key-like blade 122 insertable in a bush 120 mounted within the rocker. Perforations 124 in the blade allow the passage of those followers which are to remain ineffective, the blade presenting a contact surface in the region of the follower or followers selected to be operative. A spring 111 presses the rocker, and thus the contact surface, against the chosen follower, the rocker then being moved by the corresponding cam as the latter rotates. Different blades are inserted to select different cams or combinations of cams. The device may be fitted in or on the sewing machine in any position, for example in the same position as the selector control of the zig-zag sewing machine described in Specification 792,328. In a second embodiment (Fig. 8, not shown) the bush 120 and the blade are replaced by a control member in the form of a crank-shaft, having cheeks connected by connecting members corresponding to crank-pins. One connecting member is provided for each cam follower and the control member is rotated by a knob to present the appropriate connecting member as a contact surface opposite that follower selected to be operative. In a third embodiment (Fig. 1, not shown), a control member rotatable in the rocker by a knob is provided on its surface with a helical ridge. The member is rotated to present a part of that ridge opposite the selected follower to form a contact surface. The ridge has an oblique side so that the tapered end of each follower may ride up on to its crest as the member is rotated. The length of the ridge may be curtailed so that for one angular position of the member all the followers are inoperative. |
