| 摘要 |
1,150,754. Milling. INTERNATIONAL POLAROID CORP. 6 Oct., 1966 [7 Oct., 1965], No. 44740/66. Headings B3B and B3K. Apparatus for machining the edges of blanks of synthetic optical material to form optical elements of predetermined profile comprises a rotatable cutter assembly, a rotatable spindle assembly adapted to hold the blanks, means for biasing the cutter and spindle assemblies together for a machining operation, means for initiating drive of the spindle assembly upon engagement of the cutter with the blanks and means for varying the distance between the cutter axis and spindle axis to ensure the machining of the blank according to the predetermined profile. The spindle assembly 20 includes upper and lower shafts 24, 26 carrying clamping blocks 28, 36 and clamping means 50, e.g. hydraulic means, are provided for clamping a stack of blanks 22 therebetween. The spindle assembly 20 is mounted in a housing 16 which is pivotable about an input drive shaft 70, drive to cause the pivotal movement being transmitted through a clutch 84 to the housing. Pivotal movement of the housing 16 brings the blanks into engagement with the rotating cutter 52 which arrests the housing causing clutch 84 to slip which thereby initiates drive to the shafts 24, 26 through the gear trains 78, 80, 82 and 72, 74, 76. The upper shaft 24 carries a cam 30 which engages an adjustably positioned follower 62 located in a slide 60 above the cutter 52, the cam 30 having the required profile for the optical elements. Adjustment of the position of the follower 64 controls the size of the elements produced. The position of the follower may be automatically controlled to give first a rough heavy cut and then a final finishing cut, the spindle assembly being correspondingly controlled to make two revolutions. During the machining of the blanks the action of the slipping clutch is to bias the blanks against the cutter. After machining is completed the drive to the input shaft is reversed causing the housing to pivot away against a stop and the input shaft 70 to return to an index position determined by a ratchet-wheel 87 and pawl 89. A retractable and adjustable alignment member 42 is provided for correctly setting the blanks 22 in the clamping blocks 28, 36. In an alternative arrangement the cutter could be made movable to engage the blanks. |
