Abstract:
A head arm includes a main body, partially located with a first area above a recordable medium. The main body includes a first surface opposite to the recordable medium and a second surface opposite to the first surface. A hole extends through the main body between the first and second surfaces. The main body also has a first connector portion connectible to a driving portion; and a second connector portion connectible to a head. The through hole is formed on only one side with respect to a line that halves the first area between said first and second connector portions.

Description:
This is a divisional of application Ser. No. 09/631,915, filed Aug. 3, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to head moving mechanisms (or head actuators) for a recordable medium, and more particularly to a head arm that supports and moves the head. The recordable medium typically is a disk in form, but broadly covers various types taking the form of a card, a sheet and others. The head may move in any direction, straight, swingingly, up and down, etc. The head arm as one exemplified embodiment of the present invention is suitable for those disk units which broadly include a magnetic disk unit, optical disk unit, magneto-optic disk unit, DVD unit, CD audio player, a variety of game machines using a dedicated disk. 
     There has been a demand for quick head positioning onto a specified track in magnetic or other disk units. The head moving mechanism typically includes a head, a head arm, and a suspension that connects the head and arm. Reduced moment of inertia of the head moving mechanism is effective for the quick head positioning. A pierced head arm has been thus proposed to reduce the weight of the head arm. 
     As shown in FIG. 32, for example, a conventional head moving mechanism  10  includes a head arm  20 , a suspension  30 , and a head  40 . Hereupon, FIG. 32 is an illustrative schematic plan view of the conventional head moving mechanism  10 . The head arm  20  is connected to the suspension  30  at its top  22  and to a rotation shaft  50  at its base  24 . The head arm  20  also includes a through hole  26  that perforates from its top surface through its bottom surface for weight reduction. One or two through holes  26  are made as large as possible to the extent that the head arm  20  may maintain specified rigidity. The head arm  20  crosses a disk at its upper side of the dotted line in FIG.  32 . 
     However, the conventional disk unit has a disadvantage in that it cannot quickly position the head at a target position due to disturbance (vibration, etc.) by airflow between disks. The airflow is produced by rotations of the disks as indicated by a solid arrow A in FIG. 32, and has a deleterious effect especially in a hermetic space. In particular, where a head arm is located between the disks and support a pair of heads that read data on the upper and lower disks would narrow the hermetic space, and thus increase the effect of the airflow. 
     As shown by an arrow in FIG. 33, the airflow is sucked into the hole of the head arm, swirls, and causes vibration at frequencies commensurate with the current. Hereupon, FIG. 33 is a sectional view taken along a line B—B of the head moving mechanism  10  shown in FIG. 32 when placed between a pair of upper and lower disks  2 . A magnetic disk unit in the past rotated the disks at a relatively low rotary speed, i.e., a few thousand rpm, and the air flew at low velocity. Therefore the disturbance by the air had little effect, and no consideration has been given to a shape of the head arm in view of the airflow. 
     However, the trend toward accelerated disk speed in recent years has brought about increased disk rotating speed, which has boosted the velocity of the airflow around the head arm. Consequently, recent years have seen a nonnegligible effect of the disturbance by airflow on the disk unit. Specifically, an arm has a sectionally rectangular shape and includes a part that orthogonally crosses the airflow, thus suffering for the high air drag. In addition, the airflow greatly deflects out of top and bottom ends of surfaces orthogonal to the airflow, and vibrates the arm. Moreover, the disturbed airflow in the presence of the arm disadvantageously affects the disks and induces vibrations of the disks. As the velocity of the air increases, the disturbance by the air pressure has induced high-frequency disturbance extending up to a few kHz in addition to low-frequency disturbance. Since the according density of the disk increases year after year, it is necessary not only to improve a control performance of the head arm but also to reduce the disturbance by airflow, in order to improve a positioning performance. 
     BRIEF SUMMARY OF THE INVENTION 
     Therefore, it is an exemplified general object of the present invention to provide a novel and useful head arm, head moving mechanism, disk unit, and method of manufacturing the head arm, in which the above disadvantages are eliminated. 
     Another exemplified and more specific object of the present invention is to provide a head arm, head moving mechanism, disk unit, and method of manufacturing the head arm that permits quick positioning of the head. 
     In order to achieve the above objects, the head arm as one exemplified embodiment of the present invention comprises a main body, partially located above a recordable medium, that the main body includes a first surface opposite to the recordable medium and a second surface opposite to the first surface, the first and second surfaces having no perforation above the recordable medium as viewed from the recordable medium, a first connector portion connected to the main body, and connectible to a driving portion, and a second connector portion connected to the main body, and connectible to a head. This head arm allows no airflow to pass through the head arm, and thus undergoes little influence of disturbance such as vibration or the like. 
     The head arm as another exemplified embodiment of the present invention comprises a main body, partially located with a first area above a recordable medium, that the main body includes a first surface opposite to the recordable medium and a second surface opposite to the first surface, the first and second surfaces having a through hole, a first connector portion connected to the main body and connectible to a driving portion, and a second connector portion connected to the main body, and connectible to a head, wherein the through hole is formed on only one side with respect to a line that halves the first area. This head arm becomes lightweight because of the through hole, and also reduces disturbance by airflow, by the restricted position of the through hole. Particularly, the head arm having a plurality of through holes may effectively prevent the disturbance. 
     The head arm as still another exemplified embodiment of the present invention comprises a main body, partially located above a recordable medium, that the main body includes a first surface opposite to the recordable medium and a second surface opposite to the first surface, the first and second surfaces having a plurality of through holes formed like a mesh, a first connector portion connected to the main body, and connectible to a driving portion, and a second connector portion connected to the main body, and connectible to a head. This head arm having meshed through holes would reduce the magnitude of the airflow as passing through them. 
     The head arm as still another exemplified embodiment of the present invention comprises a main body, partially located above a recordable medium, wherein the main body includes a buffer mechanism, connected to at least one of a third surface opposite to an airflow generated above the recordable medium and a fourth surface opposite to the third surface for mitigating disturbance of the airflow, a first connector portion connected to the main body, and connectible to a driving portion, and a second connector portion connected to the main body, and connectible to a head. This head arm uses the buffer mechanism (e.g., a step, chamfered portion, projection portion formed on at least one of the third and fourth surfaces, and/or through hole that perforates the third and fourth surfaces) to restrict disturbance by the airflow. 
     The head moving mechanism as one exemplified embodiment of the present invention comprises any one of the above head arms, and a head connected to the second connector portion of the head arm. This head moving mechanism may achieve the same operation as the above-described head arms. 
     The disk unit as one exemplified embodiment of the present invention comprises any one of the above head arms, wherein the recordable medium is a disk, a head connected to the second connector portion of the head arm, a driving portion connected to the first connector portion of the head arm, a signal processor portion that handles a signal communicated between the head and the disk, a rotor portion that rotates the disk, and a controller portion that controls movements of the head, operations of the signal processor portion and rotor portion. This disk unit may achieve the same operation as the above-described head arms. 
     The method of manufacturing a head arm comprises the steps of forming a body base material having a desired thickness, providing a through hole for making the body base material lightweight, and sealing at least a part of the through hole. This manufacturing method of a head arm makes it possible to provide a lightweight head arm while preventing disturbance by airflow. 
     Other objects and further features of the present invention will become readily apparent from the following description of the embodiments with reference to accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic perspective view of a head moving mechanism as one embodiment of the present invention. 
     FIG. 2 is a schematic perspective view for explaining a formation of the head moving mechanism shown in FIG. 1 by sealing a through hole provided in the head arm with a sealing member. 
     FIG. 3 is a schematic perspective view for explaining another formation of the head moving mechanism shown in FIG. 1 by sealing a through hole provided in the head arm with a sealing member other than that shown in FIG.  2 . 
     FIG. 4 is a sectional view for illustrating a relationship between the airflow and the head arm shown in FIG. 1 having flat top and bottom surfaces. 
     FIG. 5 is a sectional view of the head arm shown in FIG. 1, in which the through hole is sealed at its top. 
     FIG. 6 is a schematic plan view of the head arm shown in FIG. 1 for explaining its area S that may cover the top of a disk and a line V that halves the area S. 
     FIG. 7 is a schematic perspective view of a head moving mechanism that includes a through hole at an upper side of the area dividing line V. 
     FIG. 8 is a schematic perspective view for explaining a method of substantially realizing the head moving mechanism shown in FIG.  7 . 
     FIG. 9 is a schematic perspective view of a head moving mechanism that includes a through hole at a lower side of the area dividing line V. 
     FIG. 10 is a schematic perspective view of a variation of the head moving mechanism shown in FIG.  7 . 
     FIG. 11 is a schematic perspective view of a variation of the head moving mechanism shown in FIG.  9 . 
     FIG. 12 is a schematic perspective view of a head moving mechanism that includes a mesh of through holes throughout an approximately entire area that covers the top of a disk. 
     FIG. 13 is a schematic plan view of the head moving mechanism shown in FIG. 1 that includes a projection portion as a buffer mechanism at its right and/or left side. 
     FIG. 14 is an exemplified sectional view taken along a line F—F shown in FIG.  13 . 
     FIG. 15 is another exemplified sectional view taken along a line F—F shown in FIG.  13 . 
     FIG. 16 is a schematic plan view of the head moving mechanism shown in FIG. 1 that includes a chamfered portion as a buffer mechanism at its right and/or left side. 
     FIG. 17 is a sectional view taken along a line G—G shown in FIG.  16 . 
     FIG. 18 is a schematic plan view of the head moving mechanism shown in FIG. 1 that includes a step (or cutaway portion) as a buffer mechanism at its right and/or left side. 
     FIG. 19 is a sectional view taken along a line H—H shown in FIG.  18 . 
     FIG. 20 is a schematic plan view of the head moving mechanism shown in FIG. 1 that includes a through hole as a buffer mechanism perforating its right and/or left side. 
     FIG. 21 is a sectional view taken along a line I—I shown in FIG.  20 . 
     FIG. 22 is a flowchart of a method of manufacturing a head moving mechanism as one exemplified embodiment of the present invention. 
     FIG. 23 is a schematic perspective view of a drawn material formed as a result of a step of forming a drawn material shown in FIG.  22 . 
     FIG. 24 is a schematic perspective view of a head arm base material formed as a result of a step of cutting a drawn material shown in FIG.  22 . 
     FIG. 25 is a schematic perspective view of a head arm base material including an axial hole and an optionally formed through hole formed as a result of a step of forming a driving-shaft hole shown in FIG.  22 . 
     FIG. 26 is a schematic sectional view of the head arm shown in FIG. 1 that includes a slant through hole. 
     FIG. 27 is a schematic sectional view for explaining an exemplified method of forming the chamfered portion shown in FIG.  16 . 
     FIG. 28 is a schematic perspective view of a head arm base material that has passed a step of forming gaps for disks shown in FIG.  22 . 
     FIG. 29 is an exemplified partial and schematic section of a head moving mechanism in which heads and suspensions are attached to a head arm shown in FIG.  28  and inserted between disks. 
     FIG. 30 is a schematic perspective view of a disk unit as one exemplified embodiment of the present invention. 
     FIG. 31 is a block diagram for illustrating a control system of the disk unit shown in FIG.  30 . 
     FIG. 32 is an exemplified schematic plan view of a conventional head moving mechanism. 
     FIG. 33 is a sectional view taken along a line B—B of the head moving mechanism shown in FIG. 32 when placed between a pair of upper and lower disks. 
    
    
     DETAILED DESCRIPTION OF INVENTION 
     A description will now be given of a head moving mechanism as one exemplified embodiment of the present invention, with reference to the drawings. In each figure, those elements which are the same are designated by the same reference numerals, and a duplicated description thereof will be omitted. The same reference numerals with an alphabetic letter attached thereto generally designate a variation of the elements identified by the reference numeral without an alphabetic letter, and reference numerals without an alphabetic letter, unless otherwise specified, comprehensively designate the element identified by the reference numerals with an alphabetic letter. Hereupon, FIG. 1 is a schematic perspective view of the head moving mechanism  100  as one exemplified embodiment of the present invention. 
     Referring to FIG. 1, the inventive head moving mechanism  100  includes a head arm  110 , a suspension  130 , and a head  140 . The head arm  110  includes a top surface  112 , a bottom surface  114 , a right side surface  116 , and a left side surface  118 . The head arm  110  is connected to a driving shaft  150  at its base  117  and to a suspension  130  at its top  119 . The head arm  110  may swing about the driving shaft  150 , and an upper side of a dotted line P is located above a disk (not shown). Suppose that the head arm  110  receives from an arrow direction A an airflow generated on a moving disk in the present embodiment. Thus the right side surface  116  faces a windward side of the head arm  110 . 
     The head arm  110  supports a pair of suspensions and heads, moves them above a disk (not shown) about the driving shaft  150 , and places them between a pair of disks  2  as will be described later. The top and bottom surfaces  112 ,  114  have a substantially sectorial shape, and the right side and left side surfaces  116 ,  118  have a substantially rectangular shape. These shapes are for exemplary purposes only, and the head arm  110  may have any other shape. A manufacturing method of the head arm  110  will be described later. The head arm, though configured to swing in the present embodiment, may have any other moving structure such as moving straight, up and down 
     The head arm  110  in the present embodiment has no through hole at an upper side of a dotted line P (i.e., at a side of the head  140  or top  119 ) on the top and/or bottom surfaces  112 ,  114 . This configuration can consequently prevent disturbance (or vibration) by airflow as passing through the through hole as shown in FIG.  33 . ‘No through hole’, to be exact, means that no through hole can be seen when viewed from outside the head arm  110 . Accordingly, the top and/or bottom surfaces  112 ,  114  have no through hole at an upper side of the dotted line P if the top and/or bottom surfaces  112 ,  114  are entirely flat, partly recessed, provided with a through hole sealed at least at its one side, or the like. The head arm  110  preferably has reduced weight to produce less moment of inertia for quick head positioning. Thus, the head arm  110  preferably has its part removed to save weight. Therefore, from the viewpoint of reduction of its weight, the top and/or bottom surfaces  112 ,  114  of the head arm  110  preferably includes a recessed portion at its one or both holes, or a sealed through hole rather than being entirely flat in an upper side area of the dotted line P. The ‘recessed portion’ is intended to comprehensively include a groove, an indentation, and any concave portions that may be formed on one surface but not perforate through the other surface, no matter what they are called. 
     FIGS. 2 and 3 show the head arm  110  including a sealed though hole  120  between the top and bottom surfaces  112 ,  114 . FIG. 2 is a schematic perspective view for explaining a formation of the head moving mechanism  100  shown in FIG. 1 by sealing the through hole  120  provided in the head arm  110  with a sealing member  102 . FIG. 3 is a schematic perspective view for explaining another formation of the head moving mechanism  100  shown in FIG. 1 by sealing the through hole  120  provided in the head arm  110  with a sealing member  104 . 
     The sealing member  102  is loaded onto the head arm  110  from the right side surface  116  of the head arm  110 , while the sealing member  104  is loaded onto the head arm  110  from the head side of the head arm  110 . The sealing member  102  is U-shaped in section, while the sealing member  104  is rectangle-shaped in section. The sealing members  102  and  104  are made of tape (e.g., Kapton tape) or metal (e.g., aluminum, and stainless steel), or the like. Needless to say, the sealing member is not required to be three-dimensional, but may be a tape that seals the through hole  120  at the top and/or bottom surfaces  112 ,  114  of the head arm  110 . From the viewpoint of the prevention of disturbance, the head arm is preferably entirely flat in the upper side area of the dotted line P on the top and bottom surfaces  112 ,  114 . Thus, the through hole  120  is preferably sealed at the top and/or bottom surfaces  112 ,  114 . 
     The number and location of the through hole  120  are illustrative in FIGS. 2 and 3. The sealing members  102  and  104  seal at least one through hole  120  among a plurality of through holes  120 . FIG. 5 shows a sectional view of the head arm with its top surface  112  sealed over its through hole  120  by a sealing member  106  made of tape or the like. However, from the viewpoint of the prevention of disturbance, the sealing members  102  and  104  preferably seal all the through holes  120 . Moreover, the sealing member may be made integral with the head arm  110 , for example, as an openable shutter that is attached to the head arm  110 . The sealing member may not be limited to seal a thorough hole provided in the head arm  110 , but may be used to seal a recess. Further, the sealing member, in the broadest sense of the term, should only reduce a sectional area of the through hole  120  to reduce the airflow, and thus may include a hole having a smaller opening area than the cross-sectional area of the through hole  120 . 
     FIG. 4 is a sectional view for illustrating a relationship between the airflow and the head arm  110  having flat top and bottom surfaces  112 ,  114  in the upper side area of the dotted line P. It may be understood as indicated in the drawing that the airflow does not pass through the inside of the head arm  110  so that the head arm  110  may be unsusceptible to vibration or other types of disturbance. 
     Referring next to FIGS. 6 through 9, a description will be given of a variation of the head arm  110  shown in FIG.  1 . FIG. 6 is a schematic plan view of the head arm  110  shown in FIG. 1 for explaining its area S that may cover the top of a disk and a line V that halves the area S. FIG. 7 is a schematic perspective view of a head moving mechanism  100   a  that includes a through hole  120  (or at least the barycenter G thereof) at an upper side (i.e., at a side of the head  140  or top  119 ) with respect to the area dividing line V. FIG. 8 is a schematic perspective view for explaining a method of substantially realizing a head moving mechanism  100   a  shown in FIG.  7 . FIG. 9 is a schematic perspective view of a head moving mechanism  100   b  that includes a through hole  120  (or at least the barycenter G thereof) at a lower side (i.e., at a side of the driving shaft  150  or base  117 ) with respect to the area dividing line V. 
     The head arms  110   a  and  110   b  of these embodiments feature no through hole  120  (or at least the barycenter G thereof) formed on the area dividing line V that will be described later. As a result, the head arms  110   a  and  110   b  can lessen the influence of the vibration by the airflow as greatly as possible, while meeting a requirement of weight reduction. 
     As described with reference to FIG. 1, the head arm  110  may not entirely cover the disk, but only its upper side area of the dotted line P may cover the disk as a result of rotation of the driving shaft  150 . To be specific, the head arm  110  covers the disk in its hatched area S shown in FIG.  6 . In FIG. 6, the line V indicates an area dividing line that halves the area S. The area dividing line V goes in a direction perpendicular to a straight line U that connects the center of the driving shaft  150  and the top  119 , and divides the top surface  112  into two equal parts. The area dividing line V is also a tangent line of a circle (not shown) whose center is a rotary axis of the driving shaft  150 . 
     The area dividing line V passes by a center of mass of a part of the head arm  110  that is over the disk. Accordingly, the head arm  110  where the through hole  120  (and its barycenter G) extends over the area dividing line V would get damaged more greatly by the influence by the airflow than that where the through hole  120  is formed in any other portion. That is the reason why the head arm of the present embodiment is configured to form the through hole  120  (or at least its barycenter G) at the only one side of the area dividing line V. 
     FIG. 7 shows the head arm  110   a  (head moving mechanism  100   a ) that includes the through hole  120  formed at an upper side (i.e., at a side of the head  140  or top  119 ) with respect to the area dividing line V. The head arm  110   a  shown in FIG. 7 includes one through hole  120 . It may however be understood that the head arm  110  that would include two through holes, one of which is sealed by with a sealing member  106  as shown in FIG. 8 may have the same effect as the head arm  110   a  shown in FIG.  7 . It goes without saying that the sealing member may take on any shape. 
     FIG. 9 shows the head arm  110   b  (head moving mechanism  100   b ) that includes the through hole  120  (or at least the barycenter G thereof) at a lower side (i.e., at a side of the driving shaft  150  or base  117 ) with respect to the area dividing line V. It may be understood that the head arm that includes a plurality of through holes  120 , some of which are sealed, as in FIG. 8 may have the same effect as the head arm  110   b.    
     When a plurality of the through holes  120  are provided, it is preferable to seal some of the through hole(s)  120  as in FIG. 8 or to locate all the through holes  120  only at one side of the area dividing line V. Moreover, the through hole  120  may be of any size as described above. Thus the through hole  120  may be replaced by a plurality of meshed holes each having a small sectional area. Referring now to FIGS. 10 through 12, a description will be given of head arms  110   c  through  110   e  (head moving mechanisms  100   c  through  100   e ) that include through holes  122  and  124  arranged like a mesh. FIG. 10 is a schematic perspective view of a head moving mechanism  100   d  that includes the through holes  122  (or at least the barycenter of their distributed area) at an upper side (i.e., at a side of the head  140  or top  119 ) with respect to the area dividing line V. FIG. 11 is a schematic perspective view of a head moving mechanism  10   e  that includes the through hole  124  (or at least the barycenter of their distributed area) at its lower side (i.e., the driving shaft  150  or base  117  side) with respect to the area dividing line V. 
     The head moving mechanism  100   c  shown in FIG.  10  and the head moving mechanism  100   d  shown in FIG. 11 respectively achieve the same effect as the head moving mechanism  100   a  shown in FIG.  7  and the head moving mechanism  100   b  shown in FIG.  9 . The through holes  122  and  124  may be formed by using a drill having a small diameter to bore holes having a small sectional opening area, or by joining a meshed metal plate to cover the opening of the through hole  120 . The metal plate for the latter formation corresponds to the aforementioned sealing member, and a description thereof will thus be omitted. The meshed through holes  122  and  124  have reduced opening areas that reduce an area the airflow may pass, thereby reducing disturbance based upon the airflow. The through holes formed with a drill having a small diameter would particularly work effectively in this respect. Accordingly, a head moving mechanism  100   e  having meshed through holes  126  throughout its substantially entire surface of an area S as shown in FIG. 12 would sufficiently reduce disturbance by airflow compared with the head moving mechanism  10  shown in FIG.  32 . FIG. 12 is a schematic perspective view of the head moving mechanism  100   e  that includes a mesh of through holes  126  throughout an approximately entire surface of the area S. 
     Referring now to FIGS. 13 through 20, a description will be given of head moving mechanisms  100   f  through  100   i  that includes a buffer mechanism at its right and/or left side. FIG. 13 is a schematic plan view of a head moving mechanism  100   f  that includes a buffer mechanism formed as a projection portion  162 . FIG. 14 is an exemplified sectional view taken along a line F—F shown in FIG. 13, and FIG. 15 is another exemplified sectional view taken along the line F—F shown in FIG.  13 . FIG. 16 is a schematic plan view of a head moving mechanism  100   g  that includes a buffer mechanism formed as a chamfered portion  164 . FIG. 17 is a sectional view taken along a line G—G shown in FIG.  16 . FIG. 18 is a schematic plan view of a head moving mechanism  100   h  that includes a buffer mechanism formed as a step (or cutaway portion)  166 . FIG. 19 is a sectional view taken along a line H—H shown in FIG.  18 . FIG. 20 is a schematic plan view of a head moving mechanism  100   i  that includes a buffer mechanism formed as through holes perforating its right side and left side surfaces  116 ,  118 . FIG. 21 is a sectional view taken along a line I—I shown in FIG.  20 . 
     The head moving mechanism  100   f  shown in FIG. 13 includes a head arm  110   f . The head arm  110   f  includes the through hole(s)  20  in desired numbers, and the projection portion  162 . The projection portion  162  may be formed level with the right side surface  116  as shown in FIG. 14, or as a convex in the middle of the right side surface  116  as shown in FIG.  15 . The projection portion  162  in the latter form may be formed in the middle as shown in FIG. 15, or biased to the top or bottom surface on the right side surface  116 . The structure of the projection portion  162  shown in FIG. 15 may allow the airflow to diffuse up and down about the head arm  110   f , and would thus be preferable to that shown in FIG.  14 . Although the projection portion  162  formed only at the left side surface  118  may also be effective to some extent in calming down the airflow, it is preferable to provide the projection portion  162  at the right side  116  as a windward side or at the both right side and left side surfaces  116 ,  118 . 
     The head moving mechanism  100   g  shown in FIG. 16 includes the head arm  110   g . The head arm  110   g  includes the through hole(s)  120  in desired numbers, and the chamfered portion  164 . The chamfered portion  164  may be formed at both sides of the right side surface  116  as shown in FIG. 17, or only at one side thereof. However, the chamfered portion  164  may preferably be formed at both sides of the right side surface  116  as shown in FIG. 17 so that airflow may diffuse up and down about the head arm  110   g . Although the chamfered portion  164  formed only at the left side surface  118  may also be effective to some extent in calming down the airflow, it is preferable to provide the chamfered portion  164  at the right side  116  as a windward side or at the both right side and left side surfaces  116 ,  118 . 
     The head moving mechanism  100   h  shown in FIG. 18 includes the head arm  110   h . The head arm  110   h  includes the through hole(s)  120  in desired numbers are provided, and the step (or cutaway portion)  166 . The step  166  may be formed at both sides of the right side surface  116  as shown in FIG. 19, or only at one side thereof. However, the step  166  may preferably be formed at both sides of the right side surface  116  as shown in FIG. 19 so that airflow may diffuse up and down about the head arm  110   h . Although the step  166  formed only at the left side surface  118  may also be effective to some extent in calming down the airflow, it is preferable to provide the step  166  at the right side  116  as a windward side or at the both right side and left side surfaces  116 ,  118 . 
     The head moving mechanism  100   i  shown in FIG. 20 includes the head arm  110   i . The head arm  110   i  includes through holes (air paths)  168  that perforate the right side and left side surfaces  116 ,  118  as shown in FIG.  21 . The through holes  168  have an effect of reducing the air pressure applied to the right side surface  116  by allowing the airflow to pass through them. The through holes  168  may be provided in any number, size, and location. 
     These buffer mechanisms may be provided in arbitrary combination; for example, the projection portion  162  shown in FIG. 14 is provided with the chamfered portion  164 . 
     The suspension  130  is made, for example, of aluminum, and may utilize any construction known in the art. The head  140  is a magnetic head in the present embodiment, but conceptually it broadly covers an optical head, a magneto-optical head, and other writing and/or reading head for a recordable medium. 
     Referring now to a flowchart shown in FIG. 22, a description will be given of a manufacturing method of the head moving mechanism  100  according to the present invention. First of all, aluminum or other materials is drawn using a die to form a bar of a drawn material having a cross section corresponding to the top surface  112  of the head moving mechanism  100  (step  1002 ). A specified length of mold may also be formed using an extrusion process in which the material is extruded rather than drawn from a die. FIG. 23 shows a schematic perspective view of the drawn material  170 . Manufacturing of the head moving mechanism  100   f  may use a die incorporating the projection portion  162  (i.e., the head arm  110   f  has a cross section as shown in FIG.  14 ), or attach the projection portion  162  as a separate part afterward. 
     Next, the drawn material  170  is cut to a desired length (step  1004 ). The desired length corresponds to a distance that allows a production of head arms in desired numbers. Thus a plurality of head arm base materials may, if required, be cut from the drawn material. FIG. 24 shows a schematic perspective view of the head arm base material  172  cut off at a dotted line shown in FIG.  23 . Subsequently, an axial hole is formed in a connecting part of the base  117  to the driving shaft  150  (step  1006 ). 
     Next, the step  1008  may be added as an option A. Alternatively, the step  1006  may be followed directly by the step  1010 . The option A includes the steps of forming the through holes  120 ,  122 .  124  and/or  126 , chamfered portion  164 , step  166 , air path  168 , and/or the like. The through hole  120  may be formed, for example, using a drill or punch. The through holes  122  through  126  and  168  may be formed, for example, using a small drill having a small diameter. FIG. 25 shows a schematic perspective view of the head arm base material  172  in which the through hole  120  and the axial hole are formed using a drill  90 . Arrows indicate moving and rotation directions of the drill  90 . 
     The through holes  120  through  126  may be perpendicular relative to the top and bottom surfaces  112 ,  114 , preferably slant, and more preferably slant toward the windward side as shown in FIG.  26 . FIG. 26 shows a schematic perspective view of the head arm shown in FIG. 1 that includes a slant through hole  121 . The slant through hole  121  can more effectively reduce disturbance by airflow than a perpendicular through hole  120 . 
     The chamfered portion  164  and step  166  may be formed using a comb-like cutter, end mill, grinder, or the like used for step  1010 . For example, as shown in FIG. 27, a tool  92  including a projection  93  having an approximately triangle cross section is moved and rotated in the arrow directions, and applied to the top  174  corresponding to the prospective top  119  to form indents  175 . The center of each indent is aligned with the center of a hatched portion. Subsequently, the hatched portions defined with a dotted line shown in FIG. 27 are eliminated using a comb-like cutter (not shown), as will be described later with reference to FIG. 28, so that the chamfered portion  164  may be formed. 
     Next, gaps for disks are formed using a comb-like cutter (not shown) (step  1010 ). Rotation of the comb-like cutter in an arrow direction shown in FIG. 28 may form gaps for disks  176 . Each gap for a disk  176  corresponds to the hatched portion shown in FIG. 27, and FIGS. 27 and 28 show the three gaps for three disks, though the number of gaps is for illustrative purposes only. Each gap for a disk  176  may be set, for example, at 1 mm. 
     Next, the step  1012  may be added as an option B. Alternatively, the step  1010  may be followed directly by the step  1014 . In option B, the sealing members  102 ,  104 , and/or  106  are formed using tape (e.g., Kapton tape) or metal (e.g., aluminum or stainless steel). Lastly, heads and suspensions are attached, and the head moving mechanism is completed (step  1014 ). FIG. 9 shows the head moving mechanism in which heads  140  and suspensions  130  are attached to the head arm  110  and inserted between disks  2 . 
     A description will now be given of a disk unit  200  including the inventive head moving mechanism  100  with reference to FIGS. 30 and 31. Hereupon, FIG. 30 is a schematic perspective view of the disk unit  200  as one exemplified embodiment of the present invention. FIG. 31 is a block diagram for illustrating a control system of the disk unit  200  shown in FIG.  30 . 
     The disk unit  200  includes in its housing  202  a disk rotation means  210 , a head arm  110 , and a circuit part  220 . The head arm  110  accommodates a coil  111  as shown in FIG. 31, and can swing about the driving shaft  150  when a current is fed through the coil  111 . The disk rotation means  210  includes a spindle motor  212  shown in FIG. 31, and a disk rotation shaft  214  engageable with a motor shaft (not shown) and the disk  2 . 
     The circuit part  220  includes a memory  212 , a control circuit  224 , and a signal processing circuit  226 . The control circuit  224  controls operations of the head  140 , the signal processing circuit  226 , and the disk rotation means  210  under control of firmware stored in the memory  212 . The control circuit  224  controls movements of the head  140  by controlling a current fed through the coil  111 . The head  140  reads data on the disk  2 , and transmits it to the signal processing circuit  226 . The signal processing circuit  226  is connected to an interface (e.g., SCSI interface) to an external device (not shown), and can demodulate the data into original information and transmit it to the external device. The signal processing circuit  226  also receives information to be recorded onto the disk from the external device, and writes it onto the disk  2  through the head  140 . 
     In operation, the control circuit  224  controls the current fed through the coil  111 , and thereby leads the head  140  to access a desired track on the disk  2 . In that event, the head  140  can quickly position to the destination track, while the aforementioned sealing member ( 120 , etc.) and/or buffer mechanism ( 162 , etc.) reduce or eliminate the effect of disturbance (vibration, etc.) by airflow. The head  140  then reads information on the destination track and transmits it to the signal processing circuit  226 , or writes onto the destination track information received from the signal processing circuit  226 . 
     Although various preferred embodiments of the present invention have been described above, the present invention is not limited to these preferred embodiments, but various variations and modifications may be made without departing from the spirit and scope of the present invention. 
     The head arm as one exemplified embodiment of the present invention does not allow airflow to pass through it, and may thus be unlikely to undergo disturbance such as a vibration by the airflow. Consequently, the head arm can quickly position the head. The head arm as another exemplified embodiment of the present invention includes a through hole, and thus becomes lightweight, while disturbance by airflow is localized and reduced by limiting a location of the through hole. In particular, the head arm provided with a plurality of the through holes might most enjoy the effect of reduced disturbance. As a result, the head arm can quickly position the head. The head arm as still another exemplified embodiment of the present invention includes the through hole formed like a mesh, and may thus reduce the magnitude of airflow that may pass through it. Resultantly, the head arm can quickly position the head. The head arm as still another exemplified embodiment of the present invention includes a buffer mechanism for reducing disturbance by airflow. Accordingly, the head arm can quickly position the head. 
     The head moving mechanism, disk unit, and method of manufacturing the head arm as one exemplified embodiment of the present invention have the same effect as the above head arm, and therefore allow the head to quickly be positioned.