Abstract:
In a disk drive suspension the conventional load beam spring section is replaced by the spring metal layer of the flexible conductor that forms the flexure providing more accurate spring function without the need of critical etching steps in the load beam spring section.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of United States Provisional Application Serial No. 60/138,709 filed Jun. 11, 1999. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to disk drive suspensions, and more particularly to disk drive suspension load beams that are more easily manufactured to exacting specifications, such as more precise spring rates (vertical stiffness of the load beam) and 1st torsion values. In a particular aspect, a difficult to control variant in the manufacturing process, the spring portion-etching step to reduce the spring portion thickness relative to the rest of the load beam, is eliminated. The invention provides an interrupted load beam in which the original spring portion of the load beam is removed and the metal layer of a flexible conductor laminate substituted for that original spring portion of the load beam. This metal layer is precise in thickness and thus highly predictable in performance. The invention provides the suspension apparatus, the method of making the suspension apparatus, and the method of applying force to a slider by means of the novel spring arrangement of the apparatus. 
     2. Description of the Related Art 
     Suspension load beams are well known and typically have a base portion that attaches to a mount plate connected to an actuator arm, a spring portion and a rigid portion that mounts a flexure and slider for positioning the slider precisely at a selected track on a disk. Rigidity or stiffness in the forwardmost beam portion of the load beam is desirable for many performance-related reasons. The spring portion on the other hand is desirably less stiff, especially in relatively short load beams such as 11 mm and 14.5 mm lengths, in order to provide the desired spring rate and 1st torsion values for the suspension. Etching away a part, e.g. 50-70% of the load beam spring portion thickness is the expedient commonly employed to reduce thickness Partial etching of the very thin load beam is problematical because precise control of the etching process is not readily achieved. Etching tolerances of as much as 20% are required. Because spring rate change is the cube of a change in thickness, the noted etched thickness tolerance can produce as much as a 70% change in spring rate, and a 20-40% change in the 1 st  torsion value. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object, therefore, of the invention to provide an improved disk drive suspension having an interrupted load beam. It is a further object to provide a load beam of improved design. A further object is to provide a load beam in which the spring portion thickness is precisely controlled and achieved without etching. Yet another object is to use the steel layer or metal foil forming a part of the flexible conductor laminate of the wireless suspension to provide a spring portion to the load beam, the original load beam spring portion having been removed as part of the load beam forming process. A further object is to provide a method of manufacturing load beams in which the thickness of the rigid or beam portion is unrelated to the thickness in the spring portion. A still further object is to provide a load beam having precisely controlled thickness in the spring portion, and greater thickness in the rigid or beam portion. 
     These and other objects of the invention to become apparent hereinafter are realized in an interrupted load beam having a base portion and a rigid portion spaced from each other across an interruption along the length of the load beam, a flexible conductor flexure attached to the load beam, the flexible conductor flexure comprising conductive traces, an insulating dielectric and a spring metal layer, the flexible conductor spring metal layer being attached to the load beam base portion and to the load beam rigid portion to join the rigid portion to the base portion in springing relation. 
     In this and like embodiments, typically, the load beam base portion has a projecting section extending in parallel with the load beam, and includes also an elongated mount plate arranged to overlie the base beam projecting section, the flexible conductor has a distal end, the flexible conductor distal end comprising an open frame formed from the flexible conductor spring metal layer and a flexure tongue supported by the frame for carrying a slider, the flexible conductor comprises a laminate of the spring metal layer, the insulating dielectric and the conductive traces, the insulating dielectric and the conductive traces traversing the load beam interruption in flexible conductor spring metal layer supported relation, and the insulating dielectric and conductive traces are bifurcated forwardly of the load beam interruption and along the length of the load beam rigid portion, and rejoined at the flexure frame. 
     In a further embodiment, the invention provides a disk drive suspension comprising a flexure and an axially elongated load beam of a predetermined thickness, the flexure being adapted to carry a slider and comprising a flexible laminate of a spring metal layer of less thickness than the load beam predetermined thickness, a dielectric layer, and one or more pairs of insulated conductive traces disposed on the dielectric layer, the load beam having a base portion for mounting the load beam to an actuator and a rigid portion, the rigid portion being spaced from the base portion to define an interruption along the axial length of the load beam, the flexure being attached to the load beam rigid portion, the flexure spring metal layer having a continued extent extending over and beyond the load beam rigid portion and over the load beam base portion, the spring metal layer continued extent being fixed to the load beam base portion and to the load beam rigid portion on opposite sides of the load beam interruption to springingly couple the load beam portions together. 
     In this and like embodiments, typically, the flexible laminate flexure has a distal end comprising an open frame formed from the flexible laminate spring metal layer and a flexure tongue supported by the frame for carrying a slider, the flexible laminate insulating dielectric and conductive traces traverse the load beam interruption in flexible laminate spring metal layer supported relation, the insulating dielectric and conductive traces are bifurcated forwardly of the load beam interruption and along the length of the load beam rigid portion, and rejoined at the flexure frame, and the load beam rigid portion is free of edge rails. 
     In its method aspects the invention provides a method of manufacturing a disk drive suspension comprising a load beam and a flexible conductor that defines a flexure, including etching from a web a load beam having a base portion, a spring portion and a rigid portion, etching away a part of the spring portion, attaching to the load beam the flexible conductor in flexure-defining relation, the flexible conductor comprising a laminate of a spring metal layer, a dielectric layer and insulated conductive traces, the flexible conductor having its the spring metal layer attached to the load beam base portion adjacent the spring portion and to the load beam rigid portion adjacent the spring portion with its the dielectric layer and conductive traces traversing the spring portion, and etching away the balance of the spring portion so that the sole spring connection between the base portion and the rigid portion is the flexible conductor spring metal layer that also forms the flexure. 
     In this embodiment, typically, there is further included shaping the load beam spring portion to have lateral extensions extending beyond the lateral edges of the base portion and the rigid portion, etching away all of the spring portion except the lateral extensions, and etching away the lateral extensions after attaching the flexible conductor to the load beam base and rigid portions; welding at laterally and longitudinally distributed locations adjacent the locus of the load beam spring portion the flexible conductor spring metal layer to the load beam base portion and to the load beam rigid portion, and maintaining the flexible conductor spring metal layer generally free of dielectric layer and conductive traces in the locations of welding of the spring metal layer to the load beam base and rigid portions. 
     In a further embodiment, the invention provides a method of applying a load on a slider carried by a disk drive suspension comprising a load beam having a base portion and a rigid portion spaced across an interruption where the load beam spring portion was located, including spring coupling the load beam base and rigid portions with a spring metal layer from a flexible conductor comprising the spring metal layer, a dielectric layer and conductive traces in lieu of the original spring portion of the load beam, and applying a force to the slider from the flexible conductor spring metal layer, and forming a flexure for supporting the slider from the flexible conductor. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The invention will be further described in conjunction with the attached drawings in which: 
     FIG. 1 is an oblique view of the suspension according to the invention, after attaching the flexible conductor and flexure combination, after partially removing the original spring portion of the load beam, and before completely removing the spring portion, viewed from the front or slider side; 
     FIG. 2 is a detailed fragmentary view thereof after removing the original spring portion completely; 
     FIG. 3 is a side elevation view of the suspension; and, 
     FIG. 4 is a view like FIG. 1 but showing only the flexible conductor and flexure. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings in detail, in FIGS. 1-4 the suspension  10  comprises a spring metal load beam  12  of any length but typically between about 11 mm and 14.5 mm or as much as the conventional 18 mm length. Load beam  12  has a base portion  14  and a rigid portion  16  spaced from each other across a gap or interruption  18  as indicated along the length of the load beam. Flexible conductor  15  extends from the electrical contact pads  17  at the load beam base portion  14  to the load beam rigid portion  16  traversing the spring portion locus  24  with plural trace conductors  19 . The trace conductors  19  are split at  20  to extend along both the left and the right hand sides of the rigid portion  16 . The flexible conductor  15  has in addition to the trace conductors  19  a stainless steel foil spring layer  21  and a dielectric layer  23  that insulates the trace conductors from the steel layer. The flexible conductor  15  is subjected to a number of processing operations that result in the steel layer  21  being shaped as best shown in FIG. 4, where the steel layer is shown shaped to define a flexure  22  comprising an open frame  32  and a tongue  34  disposed cantilevered therein for supporting a slider  35 . Flexure  22  is attached to the load beam  12  at load beam distal end  28 . The flexible conductor (non-flexure parts) is also attached at various points along the load beam  12 . The steel layer  21  is free of dielectric layer  23  and trace conductors  19  except along its centerline  25  on the load beam rigid portion  16 . On either side of the centerline  25  the steel layer extends outward to form lateral areas  27  that overlie the load beam rigid portion  16  and the load beam base portion  14  traversing the gap or interruption  18 . That is, steel layer lateral areas  27  lie in a plane parallel to the plane of the load beam rigid portion  16  and extend over the rigid portion, across interruption  18  and over the distal end  38  of the base portion  14 . The steel layer comprises a spring metal typically of a thickness of 0.0008 and 0.0012 inch in a pico size suspension which is a thickness that is desirable for the spring portion of a pico size suspension load beam but not for the beam or rigid portion  16  thereof that must be stiffer and thus thicker for a given steel. The rigid portion  16  thickness required or desired is typically too great for the spring portion  30  to perform ideally without etching reduction. Thus, in the invention the original spring portion  30  at locus  24  is removed. 
     In FIG. 1 the spring portion locus  24  is shown as it appears following removal of part, that is, essentially all, of the spring portion  16  leaving only the lateral extensions  26  of the spring portion  30 . Before removal of the indicated part of the spring portion  30 , the flexible conductor  15  including its flexure  22  noted above to be attached to the load beam  12  at the load beam distal end  28  is further attached to the load beam at its lateral areas  27  by laterally and longitudinally distributed series of welds  39  on the base portion  14  and a like series of welds  42  on the rigid portion  16 . The welds  39 ,  42  are closely adjacent the spring portion locus  24  to firmly support the flexible conductor  15  lateral areas in position and to the degree necessary for the steel layer  21  of the flexible circuit  15  to function as a spring exerting a gram-load force on the rigid portion  16  to position the slider. 
     The load beam base portion  14  has a projecting section  44  extending in parallel with the load beam  12 . An elongated mount plate  46  is arranged to overlie the base projecting section. 
     Load beam  12  in shorter versions can dispense with edge rails, but such rails may be desirable where the beam length is about 18 mm. 
     To electrically couple the suspension electronics (not shown) to the slider transducer (not shown), the trace conductors  19  extend from contact pads  17  to the flexure frame  32  for connection to slider contact pads  54 , traversing the load beam interruption  18  as a part of the laminate of flexible conductor  15 . 
     The invention method includes etching from a web the load beam  12  to have base portion  14 , a spring portion  30  and a rigid portion  16 . The spring portion  30  is then etched away leaving the lateral extensions  26  in the spring portion locus  24 . At this point the suspension  10  has the appearance shown in FIGS.  1 . The lateral extensions  26  are then etched away, leaving the appearance shown in FIG. 2, after attaching to the load beam  12  the flexible conductor  15  including flexure  22  to support the physical relation of the base portion  14  and the rigid portion  16  of the load beam in the absence of the spring portion  30 . The flexible conductor steel layer lateral areas  27  are welded as noted above on either side of interruption  18  at locus  24 . The sole spring connection between the base portion  14  and the rigid portion  16  is thus the steel layer portion of the flexible conductor  15 , and its insulated trace conductors  19 . 
     The novel load beam obtained is useful for applying a load on a slider carried by the disk drive suspension. 
     The invention thus provides an improved disk drive suspension having an interrupted load beam in which the spring portion thickness is precisely controlled and achieved without etching a controlled reduction in thickness of the load beam spring portion. The use of the steel layer of the flexible conductor to provide a spring portion to the load beam, the original load beam spring portion having been removed as part of the load beam forming process enables exacting control of thickness and thus stiffness and 1 st  torsion values without the vagaries introduced by attempting to etch a reduction in the load beam spring portion thickness. The invention method of makes the thickness of the rigid or beam portion unrelated to the thickness of the spring portion and gives greater stiffness where required without suffering the consequences of undue stiffness elsewhere. The foregoing objects are thus met.