ADJUSTABLE FIXTURE

• US 20150089791A1
• Filed: 03/24/2014
• Published: 04/02/2015
• Est. Priority Date: 09/30/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Slocum, Alexander H., Werner, Charles H. Jr., Gjvik, Erik J.
• Granted Patent: US 10,131,023 B2
• Time in Patent Office: Days
• US Class Current: 29/559
• CPC Class Codes: B23Q 1/035 with an array of longitudinally movable rods defining a reconfigurable support surface
• CPC Class Codes: B23Q 2240/002 Flat workpieces
• CPC Class Codes: B23Q 3/065 for holding workpieces being specially deformable, e.g. made from thin-walled or elastic material
• CPC Class Codes: B23Q 3/088 using vacuum means
• CPC Class Codes: Y10T 29/49998 Work holding

Abstract

The described embodiments relate to adjustable fixtures. A number of adjustable length cylindrical pins can be utilized to form a conformal support structure in accordance with a workpiece having any number of variations. At least three fixed length pins having heights lower than the adjustable length pins, can be interspersed with the adjustable length cylindrical pins to define an orientation at which the workpiece is held. Because the adjustable length pins have an uncompressed height greater than the fixed length pins, each of the adjustable length pins can be compressed in accordance with a bottom surface of the workpiece when the workpiece is pressed against the fixed length pin. In this way a conformal support structure can be formed that supports the workpiece during a machining operation.

Claims

1. A method for fixturing a workpiece, comprising:

placing a plurality of pins on a flat surface of a housing that cooperates with other surfaces to define a cavity, the plurality of pins comprising at least three fixed length pins, and a plurality of adjustable length pins;

compressing at least a portion of the plurality of adjustable length pins with a bottom surface of the workpiece until the bottom surface of the workpiece contacts at least three of the fixed length pins;

applying lateral pressure to the plurality of pins until the plurality of adjustable length pins are compressed into a hexagonal close packed array, wherein friction from adjacent pins locks each of the adjustable length pins at a height that corresponds to a bottom surface of the workpiece; and

securing the workpiece against the plurality of pins during a machining operation.

2. The method as recited in claim 1, wherein at least one of the fixed length pins has a different height than at least one other of the fixed length pins.

3. The method as recited in claim 1, further comprising:

circulating cooling fluid through the housing during the machining operation to remove heat from a bottom surface of the workpiece during the machining operation.

4. The method as recited in claim 1, further comprising:

covering a portion of a top opening of the housing with a skirt having an opening sized in accordance with a bottom surface of the workpiece.

5. The method as recited in claim 4, wherein securing the workpiece against the plurality of pins during a machining operation comprises suctioning air from the cavity of the housing to hold the workpiece against the plurality of pins during the machining operation.

6. The method as recited in claim 1, wherein the fixed length pins define an orientation of the workpiece with respect to the fixture.

7. The method as recited in claim 1, wherein a top surface of each of at least a portion of the adjustable pins is rounded allowing the adjustable pins to conform with irregular features disposed along the bottom surface of the workpiece.

8. The method as recited in claim 1, wherein compressing the adjustable length pins with a bottom surface of the workpiece comprises suctioning air from the cavity of the housing, the suction causing the workpiece to compress the adjustable length pins.

9. A fixture for supporting a workpiece during a machining operation, the fixture comprising:

a housing including a plurality of walls defining a cavity;

a lateral clamp disposed within the cavity; and

a plurality of pins disposed within the cavity, the plurality of pins comprising at least three fixed length pins and a plurality of adjustable length pins, wherein the adjustable length pins are locked at a height in accordance with a bottom surface of the workpiece when the lateral clamp imparts a lateral force on the plurality of adjustable length pins.

10. The fixture as recited in claim 9, further comprising:

a skirt disposed across a top opening of the housing and having an opening in accordance with a bottom surface of the workpiece.

11. The fixture as recited in claim 9, further comprising:

a plurality of alignment datums coupled to a top surface of the housing and configured to facilitate precise alignment of the workpiece with the fixture.

12. The fixture as recited in claim 9, wherein each of the fixed length pins are fixedly positioned along an inside surface of a bottom wall of the housing.

13. The fixture as recited in claim 10, further comprising:

a vacuum apparatus configured to draw air out of the cavity to secure a bottom surface of the workpiece against the plurality of pins.

14. The fixture as recited in claim 9, wherein each pin of the plurality of pins has a cylindrical geometry and wherein the adjustable length pins are made adjustable by an internal spring.

15. The fixture as recited in claim 9, further comprising:

a cooling fluid circulation system configured to circulate cooling fluid through the cavity of the housing during the machining operation.

16. The fixture as recited in claim 9, wherein the plurality of pins is supported by a bottom interior surface of the housing and wherein the fixed length pins are fixedly coupled to the bottom interior surface.

17. A fixturing device for securing a workpiece in place during a machining operation, the fixturing device comprising:

a housing comprising a plurality of sidewalls and a bottom wall cooperating to define a cavity, wherein top edge portions of the plurality of sidewalls cooperate to define a top opening;

an elastomeric sheet covering a portion of the top opening, the elastomeric sheet comprising a workpiece opening having a size and shape in accordance with the workpiece;

a plurality of pins arranged along an interior surface of the bottom wall, the plurality of pins comprising at least three fixed length pins and a plurality of adjustable length pins; and

a lateral clamping mechanism that applies a lateral force to the plurality of pins during the machining operation, the lateral force configured to lock the plurality of pins at a height that corresponds to a bottom surface of the workpiece.

18. The fixturing device as recited in claim 17, further comprising a bulkhead disposed within the housing that separates the plurality of pins into a first portion and a second portion.

19. The fixturing device as recited in claim 18, wherein at least one of the fixed length pins is disposed in each of the first portion and the second portion of pins.

20. The fixturing device as recited in claim 17, wherein at least a portion of the adjustable length pins have a convex top surface and a circular cross-section.