Staggered pressure zone collet assembly
View Patent ↗A collet assembly that holds two disks to be processed simultaneously uses alternating pressure zones to press against the inner diameter of the disks to hold them in place in a processing machine. While the disks to be processed are typically media disks, any type of disk processing can make use of the collet assembly of the present invention. Each pressure zone includes a contact surface on a chuck blade. When a travel stroke is initiated by an actuating device (typically an air cylinder), the drawbar pulls an angled expander rearward. The expander urges the chuck blades outward. Half of the pressure zones apply pressure (via the contact surfaces on the chuck blades) to the first disk, while the other half of the contact surfaces press against the second disk, so that both disks are held securely in position. The pressure zones that apply pressure to the first disk are interspersed with the pressure zones that apply pressure to the second disk, so that the pressure zones alternate around the circumference of the collet.
1. A collet assembly adapted for use on a disk processing machine that is capable of processing two disks simultaneously, said collet assembly comprising: a drawbar in communication with an actuating device, an expander with an expander head comprising a plurality of expander blades, said expander head having a larger diameter at an outer end than at an inner end, and a mounting chuck comprising a plurality of chuck blades that contact the disk or disks to be processed; wherein when said drawbar is actuated, said drawbar pulls said expander rearward such that said head of said expander is pulled through a travel stroke in an interior of said mounting chuck within said collet assembly, said head of said expander thereby urging said chuck blades outward so that a contact area of each said chuck blade contacts an inner diameter of the disk or disks, contact of said chuck blades with said inner diameter being accomplished without longitudinal movement of said mounting chuck, and wherein each of said chuck blades comprises a discrete contact surface, a position of said contact surface varying between alternating chuck blades, so that said chuck blades with a contact surface in a first position contact a first disk without contacting a second disk, and said chuck blades with a contact surface in a second position contact said second disk without contacting said first disk.
2. The collet assembly of claim 1 wherein:
each of said expander blades corresponds in circumferential position to and forms a pair with a corresponding one of said chuck blades, such that each said expander blade controls movement of a single corresponding chuck blade.
3. The collet assembly of claim 1 wherein:
said expander head is frustum shaped.
4. The collet assembly of claim 1 wherein:
said expander comprises ten expander blades, and said mounting chuck comprises ten chuck blades.
5. The collet assembly of claim 1 wherein:
said collet assembly further comprises a compression sleeve that limits expansion of said expander and said mounting chuck.
6. The collet assembly of claim 5 wherein:
each of said expander blades corresponds in circumferential position to and forms a pair with a corresponding one of said chuck blades, such that each said expander blade controls movement of a single corresponding chuck blade.
7. The collet assembly of claim 5 wherein:
said expander head is frustum shaped.
8. The collet assembly of claim 5 wherein:
said expander comprises ten expander blades, and said mounting chuck comprises ten chuck blades.
9. A collet assembly adapted for use on a disk processing machine that is capable of processing two disks simultaneously, said collet assembly comprising: a drawbar in communication with an actuating device, an expander with an expander head comprising a plurality of expander blades, said expander head having a larger diameter at an outer end than at an inner end, a mounting chuck comprising a plurality of chuck blades that contact the disk or disks, and a compression sleeve that limits expansion of said expander and said mounting chuck; wherein when said drawbar is actuated, said drawbar pulls said expander rearward such that said head of said expander is pulled through a travel stroke in an interior of said mounting chuck within said collet assembly, said head of said expander thereby urging said chuck blades outward so that a contact area of each said chuck blade contacts an inner diameter of the disk or disks, contact of said chuck blades with said inner diameter being accomplished without longitudinal movement of said mounting chuck, and wherein each of said chuck blades comprises a discrete contact surface, a position of said contact surface varying between alternating chuck blades, so that said chuck blades with a contact surface in a first position contact a first disk without contacting a second disk, and said chuck blades with a contact surface in a second position contact said second disk without contacting said first disk.
10. The collet assembly of claim 9 wherein:
each of said expander blades corresponds in circumferential position to and forms a pair with a corresponding one of said chuck blades, such that each said expander blade controls movement of a single corresponding chuck blade.
11. The collet assembly of claim 9 wherein:
said expander head is frustum shaped.
12. The collet assembly of claim 9 wherein:
said expander comprises ten expander blades, and said mounting chuck comprises ten chuck blades.