Swing-type actuator and method of making same

• US 5,656,877 A
• Filed: 01/04/1996
• Issued: 08/12/1997
• Est. Priority Date: 05/04/1994
• Status: Expired due to Fees

• Current Assignee: Xolox Corporation
• Original Assignee: Xolox Corporation
• Inventors: Loubier, Robert J.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Jones, Judson H.
• Application Number:
  US08/578,553
• Time in Patent Office: 586 Days
• Field of Search: 310/12, 310/13, 310/14, 360/104, 360/105, 360/106
• US Class Current: 310/13
• CPC Class Codes: G11B 21/083 on discs
• CPC Class Codes: H02K 41/0358 moving along a curvilinear path

Abstract

A swing-type actuator (10) includes a coil (20), at least one arm (40) and a thermoplastic body (50) joining the coil (20) and arm (40). The arm (40) is preferably a planar stamping having an opening (43) to which the read/write head is mounted. A body (50) is molded around portions of the arm (40) and coil (20). A journal (52) is formed in the body (50) for receiving a shaft and bearing on which the actuator (10) pivots. A grounding pin (40B) extending through the arm (40) prevents static charge build-up. Alternatively, a portion of the arm (40) may extend into the journal (50) to contact the a bearing. In another embodiment, the arm (140) includes a plastic portion (70) and a metal mounting pad (80). The plastic portion (70) may be formed of electrically conductive material to prevent static charge buildup.

Claims

1. A method of manufacturing a swing-type actuator, comprising the steps of:

forming a substantially flat arm having first and second ends;

positioning the arm in a mold;

forming a coil;

positioning the coil in the mold; and

injecting plastic into the mold and around at least a portion of the coil and around at least a portion of the first end of the arm to form a plastic body and to secure the coil and the arm to the plastic body.

2. The method of claim 1, further comprising the step of forming a journal in the body between the first end of the arm and the coil.

3. The method of claim 1, wherein the arm forming step includes forming a plurality of substantially flat arms, each having first and second ends, and wherein the arm positioning step includes positioning the plurality of arms in the mold, and wherein the injecting step includes injecting plastic around a portion of the first ends of each of the plurality of arms to secure the arms to the plastic body.

4. The method of claim 1, wherein the arm forming step comprises a stamping process.

5. The method of claim 1, further comprising the steps of forming at least one flat surface on one edge of said arm and providing a mold having a corresponding surface for aligning said arm in said mold during molding of said body.

6. The method of claim 1, further comprising the steps of securing a read/write head to the second end of the arm(s), and forming at least one wire guide in the arm(s) for receiving a wire attached to said read/write head.

7. The method of claim 1, further comprising the steps of forming a bobbin, and positioning at least a portion of the coil around the bobbin prior to positioning the coil in the mold.

8. The method of claim 3, further comprising the steps of forming a hole in each arm and inserting a grounding pin in the hole.

9. The method of claim 3, wherein the step of injecting plastic into the mold to form the plastic body includes selecting an electrically conductive plastic compound to form the body so as to render the body electrically conductive.

10. The method of claim 2, wherein at least a portion of the first end of each arm is exposed within the journal formed in the plastic body to allow contact between said first end of each arm and a bearing disposed in the journal.

11. The method of claim 2, further comprising the step of drilling at least a portion of said journal after forming the plastic body in the injecting step.

12. The method of claim 1, wherein each arm is formed of metal or metal alloy.

13. The method of claim 1, wherein the step of forming each arm includes the steps of forming a first portion of the substantially flat arm from plastic, forming a metal mounting pad, and joining the metal mounting pad to the plastic portion.

14. The method of claim 13, further comprising the steps of providing a hole in said mounting pad and securing a read/write head to said mounting pad via said hole.

15. The method of claim 14, further comprising the step of beveling the edges of said mounting pad to accommodate tooling used to secure the read/write head to said mounting pad.

16. The method of claim 13, further comprising the steps of securing a read/write head to the mounting pad, and forming at least one wire guide in the arm for receiving a wire attached to the read/write head.

17. The method of claim 16, wherein said wire guide is formed in the first portion of the arm by molding a plurality of protrusions on a surface of said first portion.

18. The method of claim 16, wherein the step of forming the first portion of the arm from plastic includes selecting an electrically conductive plastic compound for use in forming the first portion so as to render the arm electrically conductive.

19. A swing-type actuator, comprising:

at least one substantially flat arm having first and second ends;

a coil; and

a plastic body formed around at least a portion of the first end of the substantially flat arm and around at least a portion of the coil so as to secure the arm and the coil to the plastic body.

20. The swing-type actuator of claim 19, further comprising a plurality of substantially flat arms, each arm having first and second ends, and said plastic body being formed around a portion of the first end of each arm to secure the arms to the plastic body.

21. The swing-type actuator of claim 20, wherein said arms are formed of an electrically conductive material.

22. The swing-type actuator of claim 20, wherein said arms are aligned and spaced apart, and wherein said arms are electrically coupled to each other.

23. The swing-type actuator of claim 22, wherein said arms are electrically coupled by a grounding pin which extends through an opening formed in each arm.

24. The swing-type actuator of claim 20, wherein said arms are formed of metal or metal alloy in a stamping operation.

25. The swing-type actuator of claim 20, wherein said arms are at least partially formed of a non-metal, such as plastic.

26. The swing-type actuator of claim 20, further comprising a journal formed in the plastic body.

27. The swing-type actuator of claim 26, wherein at least a portion of the first ends of the arms are exposed in the journal.

28. The swing-type actuator of claim 26, wherein said journal is at least partially formed by a drilling operation, and a portion of the first end of at least one arm is exposed in the journal following the drilling operation.

29. A swing-type actuator which comprises:

a coil;

an arm for carrying a read/write head, said arm having a first end and a second metal end; and

a molded thermoplastic body including a journal and having a first portion molded about a portion of said coil so as to join said coil to said body and a second portion molded about said first end of said arm so as to join said arm to said body.

30. A swing-type actuator according to claim 29, wherein said second metal end of said arm includes means for attaching a read/write head to said arm.

31. A swing-type actuator according to claim 30, wherein said means for attaching comprises a hole extending through said second metal end of said arm.

32. A swing-type actuator according to claim 29, further comprising a grounding pin and wherein said arm includes a hole for receiving said grounding pin.

33. A swing-type actuator according to claim 32, wherein said grounding pin extends through said arm and outwardly from said body.

34. A swing-type actuator according to claim 32, further comprising at least two arms and wherein said grounding pin connects each of said least two arms to ground.

35. A swing-type actuator according to claim 29, wherein a portion of said arm is exposed within said journal.

36. A swing-type actuator according to claim 35, wherein said arm is connected to ground through contact with a bearing disposed in said journal.

37. A swing-type actuator according to claim 29, wherein said arm includes at least one wire guide formed therein for receiving a wire which attaches to a read/write head located at said second metal end of said arm.

38. A swing-type actuator according to claim 29, further comprising a bobbin having a body, a plurality of terminal pin sleeves having terminal pins disposed therein and a bridge member joining said bobbin body and said terminal pin sleeves.

39. A swing-type actuator according to claim 38, wherein said coil includes a plurality of lead wires attached to said terminal pins and said coil is disposed about said bobbin body.

40. A swing-type actuator according to claim 29, wherein said first end of said arm includes a feature which cooperates with a portion of said body to secure said arm to said body.

41. A swing-type actuator according to claim 40, wherein said arm includes a generally flat portion of uniform thickness extending between said first and second ends.

42. A swing-type actuator according to claim 29, wherein said arm includes at least one flat surface on one edge thereof for aligning said arm in a mold.

43. A swing-type actuator according to claim 42, wherein said body surrounds a portion of said flat surface.

44. A swing-type actuator according to claim 29, wherein said first end of said arm is made of metal and is integral with said second metal end of said arm.

45. A swing-type actuator according to claim 44, wherein said arm is a stamping.

46. A swing-type actuator according to claim 29, wherein said first end of said arm is made of a plastic material and said second metal end comprises a metal mounting pad secured to said first end of said arm.

47. A swing-type actuator according to claim 46, wherein said plastic material comprises a conductive plastic material.

48. A swing-type actuator according to claim 46, wherein said metal mounting pad includes a securement portion for securing said mounting pad to said first end of said arm.

49. A method of manufacturing a swing-type actuator which comprises the steps of:

positioning a metal mounting pad in a mold;

positioning a coil in said mold; and

injecting a plastic material into said mold to form;

a plastic body attached to said coil; and

a plastic arm which extends between said plastic body and said metal mounting pad.

50. A method of manufacturing a swing-type actuator according to claim 49, wherein said plastic material comprises an electrically conductive material.

51. A method of manufacturing a swing-type actuator according to claim 50, wherein said coil includes lead wires connected to terminal pins and said method further comprises positioning a non-conductive bobbin and terminal pin sleeves in said mold and using said non-conductive bobbin and terminal pin sleeves to insulate said leads wires and terminal pins from said electrically conductive material.

52. A method of manufacturing a swing-type actuator according to claim 49, wherein said step of injecting comprises a first step of injecting a plastic material to form said plastic arm and a second step of injecting a plastic material to form said plastic body.

53. A method of manufacturing a swing-type actuator according to claim 52, wherein said plastic material used to form said plastic arm comprises an electrically conductive material and said plastic material used to form said plastic body comprises a non-conductive plastic material.

54. A method of manufacturing a swing-type actuator according to claim 49, further comprising forming wire guides on said plastic arm.

55. A method of manufacturing a swing-type actuator according to claim 49, further comprising providing said metal mounting pad with means for attaching a read/write head thereto and with a securement portion for securing said metal mounting pad to said plastic arm.

56. A method of manufacturing a swing-type actuator according to claim 49, wherein said step of positioning said metal mounting pad comprises positioning a plurality of metal mounting pads in said mold and said step of injecting comprises forming a plurality of plastic arms, each extending between one of said plurality of metal mounting pads and said plastic body.

57. An actuator for positioning a read/write head in a memory storage device which comprises:

a coil;

an arm for carrying a read/write head, said arm having first and second ends and comprising a plastic portion and a metal portion; and

a molded thermoplastic body having a first portion molded about a portion of said coil to join said coil to said body, and a second portion molded about said first end portion of said arm to join said arm to said body.

58. An actuator according to claim 57, wherein the metal portion of the arm includes a through-hole.

59. An actuator according to claim 57, wherein said body includes a through-hole.

60. An actuator for positioning a read/write head in a memory storage device which comprises:

a coil;

a plurality of arms for carrying a read/write head, each of said plurality of arms having a first end and a second end and comprising a plastic portion and a metal portion; and

a molded thermoplastic body having a first portion molded about a portion of said coil to join said coil to said body, and a second portion molded about the first end portion of each of said plurality of arms to join each of said plurality of arms to said body.

61. An actuator according to claim 60, wherein the metal portion of each of said plurality of arms includes a through-hole.

62. An actuator according to claim 60, wherein said body includes a through-hole.