Abstract:
The suspension for a head assembly is capable of securely limiting the small static electricity, which cannot be limited by improving a factory environment. In the suspension of the present invention, a gimbal section is provided to a front end of the suspension and capable of holding a slider. A terminal section is provided to a base end of the suspension and electrically connected to a magnetic disk drive unit. Terminals are formed in the terminal section and connected to a cable pattern, which will be connected to the slider. A short pattern is formed in an edge part of the terminal section, and one end of the short pattern is connected to a first terminal of the terminals. The edge part of the terminal section is bent so as to elastically make the other end of the short pattern contact a second terminal of the terminals. A slit is formed in the terminal section, so that the second terminal is capable of leaving from the short pattern.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a suspension for a head assembly of a magnetic disk drive unit and a head assembly having the suspension. 
     A plan view of a magnetic disk drive unit is shown in FIG.  5 . The magnetic disk drive unit  100  has a housing  102  in which a magnetic disk  104  and an actuator  106  for positioning a magnetic head are assembled. An arm  108  is actuated by the actuator  106 . A suspension  110  is provided to a front end of the arm  108 . There is provided a slider  112 , which has the magnetic head in a bottom face facing the magnetic disk  104 , at a front end of the suspension  110 . A head assembly comprises: the arm  108 ; the suspension  110  fixed to the arm  108 ; and the slider  112  mounted on the suspension  110 . 
     In FIG. 6, the suspension  110  is fixed to the arm  108 , and the slider  112  is mounted on the suspension  110 . A gimbal section  114 , on which the slider  112  is mounted, is formed at a front free end of the suspension  110 . There are formed a plurality of terminals  116 , which will be electrically connected to terminals of the slider  112 , in the gimbal section  114 . A cable pattern  118  is formed on a surface of the suspension  110  and insulated therefrom by an insulating layer. The cable pattern  118  electrically connects terminals  120 , which are formed in a base end part of the suspension  110 , to the terminals  116 . The terminals  120  are formed in an outer face of a terminal section  111 , which is formed into an L-shape by bending a part of a base member of the suspension  110 . A flexible printed circuit is connected to the terminals  120 , so that a control circuit of the magnetic disk drive unit can be electrically connected to the slider  112 . 
     These days, in steps of assembling the head assembly, magnetic heads are apt to be damaged by static electricity. Recently, recording density of magnetic disks are higher, so magnetic heads must be smaller and structures of sliders must be complex. Therefore, the magnetic heads are apt to be easily damaged by the static electricity. Several years ago, resisting voltage of the magnetic heads against the static electricity were about 20-50 V; these days, the resisting voltage thereof is 5 V or less. In the conventional steps of assembling the head assembly, charging the static electricity was restricted by improving factory environment. However, it is impossible to limit the static electricity to 5 V or less by improving the factory environment. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a suspension for a head assembly capable of securely limiting the small static electricity, which cannot be limited by improving the factory environment. Even if the resisting voltage of a magnetic head is about 5 V, damaging the magnetic head by the static electricity can be prevented by the suspension. 
     Another object of the present invention is to provide a suspension for a head assembly capable of easily assembling the head assembly and improving manufacturing yield. 
     Further object of the present invention is to provide a head assembly having the suspension. 
     To achieve the objects, the present invention has following structures. 
     Namely, a basic structure of the suspension of the present invention comprises: a gimbal section being provided to a front end of the suspension and capable of holding a slider; a terminal section being provided to a base end of the suspension and electrically connected to an electric circuit of a magnetic disk drive unit; a plurality of terminals being formed in the terminal section, the terminals being connected to a cable pattern, which will be connected to the slider; and a short pattern being formed in an edge part of the terminal section, one end of the short pattern being connected to a first terminal of the terminals, wherein the edge part of the terminal section is bent so as to elastically make the other end of the short pattern contact a second terminal of the terminals, and a slit is formed in the terminal section, whereby the second terminal is capable of leaving from the short pattern. 
     In the suspension, the short pattern, the cable pattern and the terminals may be made by etching an electrically conductive layer, which is formed on and electrically insulated from a base member of the suspension. 
     In the suspension, four terminals, which will be electrically connected to the slider, may be formed in the terminal section, two of the four terminals may be provided on an inner side, and the other two may be provided on an outer side, the short patterns for respectively connecting the inner terminals to the outer terminals may be formed in the terminal section, and the edge part of the terminal section may be bent so as to respectively connect the inner terminals to the outer terminals. 
     Another basic structure of the suspension of the present invention comprises: a gimbal section being provided to a front end of the suspension and capable of holding a slider; a terminal section being provided to a base end of the suspension and electrically connected to an electric circuit of a magnetic disk drive unit; a plurality of terminals being formed in the terminal section, the terminals being connected to a cable pattern, which will be connected to the slider; and a short pattern being formed in an edge part of the terminal section, one end of the short pattern being connected to a first terminal of the terminals, wherein a slit is formed in the terminal section, whereby the edge part of the terminal section can be bent and a second terminal of the terminals is capable of leaving from the short pattern. 
     The head assembly of the present invention comprises: the above described suspension; and a slider being held by the gimbal section of the suspension, wherein the cable pattern connects the terminals to the slider, and the cable pattern is formed on and electrically insulated from the base member of the suspension. 
     In the suspension and the head assembly of the present invention, the magnetic head, which is mounted on the suspension, can be securely protected from the static electricity. The head assembly can be easily assembled without damaging the magnetic head. Therefore, the magnetic head, whose resisting voltage is low and which cannot be treated in the conventional assembling step, can be easily treated, and the yield of manufacturing the head assembly can be improved. 
     Further, the countermeasure to the static electricity is executed while manufacturing the suspension, so an additional step for preparing the countermeasure to the static electricity is not required. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which: 
     FIG. 1 is a partial perspective view of a suspension for a head assembly of an embodiment of the present invention, wherein a terminal section is shown; 
     FIG. 2 is a plan view of the terminal section, which is not bent; 
     FIG. 3 is a plan view of another example of short patterns, etc. formed in the terminal section; 
     FIG. 4 is an explanation view of a contact portion and a terminal, which are separated; 
     FIG. 5 is a plan view of the magnetic disk drive unit; and 
     FIG. 6 is a perspective view of the arm to which the suspension is attached. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     FIG. 1 is a partial perspective view of a suspension of the present embodiment, wherein a terminal section, which has a unique constitution, is shown. 
     A terminal section  111 , in which a plurality of terminals  120   a - 120   d  are provided, is extended from an edge of a base member of a suspension  110  and formed into an L-shape by bending the base member. The terminals  120   a - 120   d  are provided on an outer face of the terminal section  111 . The four terminals  120   a - 120   d  are linearly arranged in the terminal section  111 , and their surfaces are exposed. Cables of a cable pattern  118 , which is formed on a surface of the suspension  110 , are respectively connected to the terminals  120   a - 120   d , so that the terminals  120   a - 120   d  are electrically connected to a slider  112  held on the suspension  110 . The cable pattern  118 , which has a predetermined pattern of the cables, and the terminals  120   a - 120   d  are formed by etching an electrically conductive layer, which is formed on and electrically insulated from the base member of the suspension  110 . 
     Characteristic points of the present embodiment are: short patterns  10   a  and  10   b , which electrically short the terminals  120   a - 120   d  in the terminal section  111 ; and an edge part of the terminal section  111  is bent so as to make the short patterns contact the terminals  120   a - 120   d  by elasticity of the base member of the suspension  110 . 
     The short pattern  10   a  shorts the terminals  120   a  and  120   b ; the short pattern  10   b  shorts the terminals  120   c  and  120   d . To avoid a damage of a magnetic head which is caused by the static electricity, a closed circuit is required, so all the terminals  120   a - 120   d  need not be electrically shorted simultaneously. 
     The short patterns  10   a  and  10   b  are formed in the terminal section  111 , on which the terminals  120   a - 120   d  are formed, and provided to close to the edge part, which is bent. 
     In the present embodiment, the edge part of the terminal section  111  is bent, at the right angle, along a line A (see FIG. 2) extended in the longitudinal direction of the terminal section  111 , so that an extended portion  12  is formed. Both end parts of the extended portion  12  are upwardly bend to form vertical portions  14   a  and  14   b . Inner end parts of the vertical portions  14   a  and  14   b  are outwardly bent to form contact portions  16   a  and  16   b , which face the surface of the terminal section  111 . The contact portions  16   a  and  16   b  are elastically pressed onto the terminals  120   a  and  120   d  in the terminal section  111 . 
     When the contact portions  16   a  and  16   b  elastically contact the terminals  120   a  and  120   d , the short pattern  10   a  electrically shorts the terminals  120   a  and  120   b  and the short pattern  10   b  electrically shorts the terminals  120   c  and  120   d . Conductive material of ends of the short patterns  10   a  and  10   b , which respectively contact the terminals  120   a  and  120   d , must be exposed. 
     As described above, the short pattern  10   a  electrically shorts the terminals  120   a  and  120   b  and the short pattern  10   b  electrically shorts the terminals  120   c  and  120   d . Thus, in the present embodiment, one end of the short pattern  10   a  is electrically connected to the terminal  120   b ; the other end thereof is extended until reaching the contact portion  16   a  so as to elastically contact the terminal  120   a . On the other hand, one end of the short pattern  10   b  is electrically connected to the terminal  120   c ; the other end thereof is extended until reaching the contact portion  16   b  so as to elastically contact the terminal  120   d.    
     The short patterns  10   a  and  10   b  and the terminals  120   a - 120   d  can be formed simultaneously. They are formed by the steps of: forming a resin layer, which acts as an insulating layer, on the surface of the base member of the suspension  110 ; forming the electrically conductive layer on the resin insulating layer by spattering, etc.; and etching the conductive layer, so that the short patterns  10   a  and  10   b  and the terminals  120   a - 120   d  can be formed simultaneously. Since the one end of the short pattern  10   a  is connected to the terminal  120   b , the terminals  120   a  and  120   b  are electrically shorted by elastically pressing the other end of the short pattern  10   a  onto the terminal  120   a . Since the one end of the short pattern  10   b  is connected to the terminal  120   c , the terminals  120   c  and  120   d  are electrically shorted by elastically pressing the other end of the short pattern  10   b  onto the terminal  120   d . The contact portions  16   a  and  16   b  are respectively biased toward the terminals  120   a  and  120   d  by the elasticity of the base member of the suspension  110 . With this structure, the terminals  120   a  and  120   b  and the terminals  120   c  and  120   d  are always electrically shorted by the contact portions  16   a  and  16   b.    
     As shown in FIG. 1, there are formed slits  18   a  and  18   b  in the terminal section  111 . By forming the slits  18   a  and  18   b , the terminals  120   a  and  120   d  are capable of leaving from the contact portions  16   a  and  16   b . When characteristics of the slider  112 , which is mounted on the suspension  110 , are examined or the head assembly is mounted onto a disk drive unit, the contact portions  16   a  and  16   b  are left from the terminals  120   a  and  120   d  so as not to electrically short the terminals  120   a  and  120   b  and the terminals  120   c  and  120   d.    
     A plan view of the terminal section  111 , which is not bent, is shown in FIG.  2 . The terminals  120   a - 120   d  are linearly arranged with regular separations, and the cables of the cable pattern  118  are respectively connected thereto. The edge part of the terminal section  111  will be bent as described above, and the short patterns  10   a  and  10   b  are formed in the part. The one end of the short pattern  10   a  is connected to the terminal  120   b , and the other end thereof is extended until reaching the contact portion  16   a ; the one end of the short pattern  10   b  is connected to the terminal  120   c , and the other end thereof is extended until reaching the contact portion  16   b.    
     In FIG. 2, the terminal section  111  is bent along the line A so as to form the extended portion  12 . The extended portion  12  is formed by outwardly bending the terminal section  111 , at the right angle, along the line A. The vertical portions  14   a  and  14   b  are formed by bending the terminal section  111  along lines B. The terminal section  111  is inwardly bent along the lines B, so that the vertical portions  14   a  and  14   b  are formed. The contact portions  16   a  and  16   b  are formed by bending the terminal section  111  along lines C. The terminal section  111  is outwardly bent along the lines C, so that the contact portions  16   a  and  16   b  are formed. 
     The contact portions  16   a  and  16   b  are elastically contact the terminals  120   a  and  120   d  respectively. Thus, to securely make the contact portions  16   a  and  16   b  contact the terminals  120   a  and  120   d , the lines A, B and C must be correctly defined when the terminal section  111  is bent. 
     The slits  18   a  and  18   b  are designed to allow parts of the terminal section  111 , in which the terminals  120   a  and  120   d  are respectively provided, to move. Further, the slits  18   a  and  18   b  allow the terminal section  111  to be bent, so that the vertical sections  14   a  and  14   b  and the contact portions  16   a  and  16   b  can be formed. In the present embodiment, the slits  18   a  and  18   b  are formed into L-shapes, but the shapes of the slits  18   a  and  18   b  are not limited to the L-shapes. 
     The suspension  110  is formed into a described shape. The terminal section  111  is simultaneously formed when the suspension  110  is formed. The slits  18   a  and  18   b , etc. are also simultaneously formed when the suspension  110  is formed. 
     The terminal section  111  is bent after the suspension  110  is formed into the prescribed shape, so the terminal section  111 , the extended portion  12 , the vertical portions  14   a  and  14   b  and the contact portions  16   a  and  16   b  can be formed in a bending step, in which the terminal section  111  is formed. 
     Another embodiment of the short patterns  10   a  and  10   b , the slits  18   a  and  18   b  and the bent portions will be explained with reference to FIG.  3 . The short patterns  10   a  and  10   b  are formed by respectively extending the terminals  120   b  and  120   c . Width of the short patterns may be designed optionally. The slits  18   a  and  18   b  may be formed into narrow holes. Further, bending positions of the vertical portions  14   a  and  14   b  and the contact portions  16   a  and  16   b  are also designed optionally. 
     By forming the short patterns  10   a  and  10   b  in the terminal section  111 , in which the terminals  120   a - 120   d  are formed, and bending the edge part of the terminal section  111 , the terminals  120   a  and  120   b  and the terminals  120   c  and  120   d  are respectively shorted by the short patterns  10   a  and  10   b . Therefore, the destruction of the slider  112 , which is occurred when the slider  112  is mounted onto the suspension  110 , can be effectively prevented. 
     In the conventional method of assembling a head assembly, the head slider  112  is apt to be damaged when the head assembly, on which the head slider  112  has been mounted, is assembled to a magnetic disk drive unit. After the head assembly is assembled to the disk drive unit, the slider  112  is connected to an electric circuit, so that no static electricity influences the slider  112 . On the other hand, before the head assembly is assembled to the disk drive unit, the slider  112  is connected to no electric circuit, so that the static electricity badly influences the slider  112 . 
     In the suspension  110  of the present embodiment, the slider  112  is mounted in the state, in which the terminals  120   a  and  120   b  and the terminals  120   c  and  120   d  are shorted, so that the destruction of the slider  112  by the static electricity can be securely prevented. Electrically shorting the terminals  120   a - 120   d  is the best way to securely avoid the destruction of the slider  112  by the static electricity. By employing the structure of the present embodiment, the sliders, whose resisting voltage is about 5 V and which cannot be treated by the conventional countermeasure, can be easily treated. 
     When the characteristics of the slider  112 , which has been mounted on the suspension  110 , are examined, the terminals  120   a  and  120   d , which respectively contact the contact portions  16   a  and  16   b , is pushed by proper means, e.g., a probe, so as to curve the terminal section  111  and leave the contact portions  16   a  and  16   b  from the terminals  120   a  and  120   d . By leaving the contact portions  16   a  and  16   b  from the terminals  120   a  and  120   d , all the terminals  120   a - 120   d  can be electrically separated and act like ordinary terminals. After the examination, the terminals  120   a  and  120   d  are returned to initial positions by the elasticity of the terminal section  111 , so that the contact portions  16   a  and  16   b  contact the terminals  120   a  and  120   d  and the terminals  120   a  and  120   b  and the terminals  120   c  and  120   d  are electrically shorted. 
     In the suspension  110  of the present embodiment, the examination before assembling to the disk drive unit can be properly executed, and the bad influence of the static electricity can be securely prevented. 
     Note that, after the head assembly is assembled to the disk drive unit, the contact portions  16   a  and  16   b  must be left from the terminals  120   a  and  120   d  so as to electrically separate the terminals  120   a - 120   d . Thus, the terminals  120   a  and  120   d , which are contacted by the contact portions  16   a  and  16   b , are bent, beyond an elastic limit, to move away from the contact portions  16   a  and  16   b  (see FIG. 4) so as to separate the terminals  120   a  and  120   d  from the contact portions  16   a  and  16   b . By this treatment, the head assembly can be used in the disk drive unit as well as the conventional head assembly. 
     By employing the suspension  110  of the present embodiment, the bad influence of the static electricity to the magnetic head can be securely prevented, the magnetic heads whose resisting voltage are considerably low can be treated easily. By securely removing the bad influence, reliability of the products can be increased, so that the manufacturing yield can be improved. Since the cable pattern  118 , the terminals  120   a - 120   d  and the short patterns  10   a  and  10   b  can be formed simultaneously, the countermeasure against the static electricity can be executed in the conventional manufacturing step without an additional step for the countermeasure against the static electricity. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.