CA1109557A - Disk file with symmetrical hollow base - Google Patents
Disk file with symmetrical hollow baseInfo
- Publication number
- CA1109557A CA1109557A CA304,089A CA304089A CA1109557A CA 1109557 A CA1109557 A CA 1109557A CA 304089 A CA304089 A CA 304089A CA 1109557 A CA1109557 A CA 1109557A
- Authority
- CA
- Canada
- Prior art keywords
- disk
- base
- assembly
- plane
- housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
- G11B5/54—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head into or out of its operative position or across tracks
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B17/00—Guiding record carriers not specifically of filamentary or web form, or of supports therefor
- G11B17/22—Guiding record carriers not specifically of filamentary or web form, or of supports therefor from random access magazine of disc records
- G11B17/30—Guiding record carriers not specifically of filamentary or web form, or of supports therefor from random access magazine of disc records wherein the playing unit is moved according to the location of the selected record
Landscapes
- Moving Of Heads (AREA)
- Packaging Of Annular Or Rod-Shaped Articles, Wearing Apparel, Cassettes, Or The Like (AREA)
Abstract
DISK FILE WITH SYMMETRICAL HOLLOW BASE
Abstract of the Disclosure A disk file wherein the actuator(s) for the magnetic head(s) are mounted within and supported by a hollow symmetrical generally ring-shaped base as closely as possible to a neutral plane that divides opposing walls of the base into substantially symmetrical parts. The disk stack is supported with its spindle normal to the neutral plane and its center of gravity substantially coincident with said plane. This substantially eliminates bending of the base out of the plane of the disks resultant from temperature gradients and from reaction forces set up when the voice coil motor actuator moves the head(s).
Abstract of the Disclosure A disk file wherein the actuator(s) for the magnetic head(s) are mounted within and supported by a hollow symmetrical generally ring-shaped base as closely as possible to a neutral plane that divides opposing walls of the base into substantially symmetrical parts. The disk stack is supported with its spindle normal to the neutral plane and its center of gravity substantially coincident with said plane. This substantially eliminates bending of the base out of the plane of the disks resultant from temperature gradients and from reaction forces set up when the voice coil motor actuator moves the head(s).
Description
- - - - - - - - - - - - -1. Field of the Invention 21 This invention relates primari7y to disk file apparatus 22 of the accessing head type, wherein a magnetic read/write 23 head is movable radially of a recording surface of a rotating 24 magnetic disk for reading or recording data in digital form at selectable radial locations or tracks. The invention 26 relates more particularly to such an apparatus wherein a 27 hollow base is provided and so configured, and a disk/spindle/
28 housing assembly and voice cGil motor ~CM) are so mounted 29 there~n and thereto, that during VCM operation, bending moments in the base are substantially eliminated and a 31 substantially un;form temperature differential is maintained 32 between the lnterior and exterior surfaces o~ the base.
:
~ ` ~ ' - , ~ , .
~: .. . . . , . . . . :. . ~ ~ : : :
1 In disk files of the accessing head type9 the disks
28 housing assembly and voice cGil motor ~CM) are so mounted 29 there~n and thereto, that during VCM operation, bending moments in the base are substantially eliminated and a 31 substantially un;form temperature differential is maintained 32 between the lnterior and exterior surfaces o~ the base.
:
~ ` ~ ' - , ~ , .
~: .. . . . , . . . . :. . ~ ~ : : :
1 In disk files of the accessing head type9 the disks
2 have traditionally been supported on a vertical spindle .
3 projecting upwardly from a flat horizontal baseplate; and a
4 carrier/arm assembly has been movable horizontally on the baseplate in response to energization of the coil of a VCM
6 actuator to carry magnetic heads ~'nto transduc;ng engagement 7 with a selected track of a particula~r d;sk. Reaction to 3 this movement of the heads by the actuator sets up bending g moments in the baseplate because the neutral axi's of the flat baseplate is below the force cen~er of the VCM.and the 11 mass centens o~ ~he VCM and of ~he disk stack. These bending 12 moments can cause dynamic bending of the spindle and track 13 misregistrat~on error. Moreover, since there is a temperature 14 differential between the upper and lower surfaces of the baseplate, the resultant thermal expansion causes static 16 out-of-plane bending of the bas-eplate.
17 To reduce this bending, it has been proposed in U. S.
18 Patent 3,768,083 to provide two flat overlying baseplate .' 19 sections~ One is made very rigid and supports the d;.sk pac~, magnetic heads, head support and sp;ndle; and the 21 ~other supports the heavy pole pieces of the VCM. However~
22 there is. still out-of-plane bending because the center of 23 force.Qf the''VCM and the centers of grav;ty of the VCM and 24 disks are placed- a significant distanoe from the neu.tral plane of the base'plate; and distortion still occurs due to 26 the difference in temperature between t~e upper and 'lower 27 surfaces of the baseplate.
28 ~ Thcse problems are substantially eliminated in ~he disk 2g ~ile embodying the p'resent invent;on, wherein each VCM
actuator is mounted within and supporte.d by a ho110w generally :
SA977005 j -2-.
.
~9~7 1 ring-shaped symmetr;cal base as closely as~possible to a 2 neutral plane that divides opposing walls o~ the base into 3 two substantially symmetrical parts; and the disk/spindle/housing assembly ;s independently secured ~o the base w;th its spindle normal to the neutral plane and i~s center of gravity 6 substantially coincident therewith.
7 This improved configuration is not disclosed or su~gested by the most pertinent prior art known to appl;cant and to 9 those substantively involved in the preparat;on of this application. U. S. Patent 4,005,490 shows a cylindrical 11 frame and b~;dge plates for supporting centrally a disk, 12 spindle and motor in a symme~rical arrangement; however, the 13 motor comprises a rotor surrounding a stator, and only fixed 14 heads are employed, and there is no-VCM or equivalent translationally movable actuator mounted as herein described for controll;ng 1~ the heads.
17 A disk~ile apparatus marke~ed by Data Products Corporation 18 ha:s plural access mechanisms mounted on the exterior of a 19 cast metal shroud surrounding disk stack. However, the shroud dpp~rentl~ does not support the disk stack and spindle, 21 which appear to be suppor~ed from benea~h. Hence, the a2 shroud does not function as a base.
23 U. S. Patent 4,008,492 discloses a magnetic disk memory 24 device wberein a disk pack is enclosed in a shroud. The 2S shroud has a chamber to which air is su-pplied to cool the `26 disks to reduce the temperature gradien~ between componenls 27 wlthin the chamber. However, this arrangement does not 28 propose a solution tn the dynamic out-of-plane bending 29 prob7em with which applicant is also concerned. The disk file apparatus according to the present invention subs~an:-31 tially eliminates both dynamic and static out-of-plane 32 bending of the base.
. . ' ' 2 The disk file apparatus embodying the present invention 3 comprises a substantial1y symmetrical hollow generally ring-4 shaped base divided into two substantially identical parts
6 actuator to carry magnetic heads ~'nto transduc;ng engagement 7 with a selected track of a particula~r d;sk. Reaction to 3 this movement of the heads by the actuator sets up bending g moments in the baseplate because the neutral axi's of the flat baseplate is below the force cen~er of the VCM.and the 11 mass centens o~ ~he VCM and of ~he disk stack. These bending 12 moments can cause dynamic bending of the spindle and track 13 misregistrat~on error. Moreover, since there is a temperature 14 differential between the upper and lower surfaces of the baseplate, the resultant thermal expansion causes static 16 out-of-plane bending of the bas-eplate.
17 To reduce this bending, it has been proposed in U. S.
18 Patent 3,768,083 to provide two flat overlying baseplate .' 19 sections~ One is made very rigid and supports the d;.sk pac~, magnetic heads, head support and sp;ndle; and the 21 ~other supports the heavy pole pieces of the VCM. However~
22 there is. still out-of-plane bending because the center of 23 force.Qf the''VCM and the centers of grav;ty of the VCM and 24 disks are placed- a significant distanoe from the neu.tral plane of the base'plate; and distortion still occurs due to 26 the difference in temperature between t~e upper and 'lower 27 surfaces of the baseplate.
28 ~ Thcse problems are substantially eliminated in ~he disk 2g ~ile embodying the p'resent invent;on, wherein each VCM
actuator is mounted within and supporte.d by a ho110w generally :
SA977005 j -2-.
.
~9~7 1 ring-shaped symmetr;cal base as closely as~possible to a 2 neutral plane that divides opposing walls o~ the base into 3 two substantially symmetrical parts; and the disk/spindle/housing assembly ;s independently secured ~o the base w;th its spindle normal to the neutral plane and i~s center of gravity 6 substantially coincident therewith.
7 This improved configuration is not disclosed or su~gested by the most pertinent prior art known to appl;cant and to 9 those substantively involved in the preparat;on of this application. U. S. Patent 4,005,490 shows a cylindrical 11 frame and b~;dge plates for supporting centrally a disk, 12 spindle and motor in a symme~rical arrangement; however, the 13 motor comprises a rotor surrounding a stator, and only fixed 14 heads are employed, and there is no-VCM or equivalent translationally movable actuator mounted as herein described for controll;ng 1~ the heads.
17 A disk~ile apparatus marke~ed by Data Products Corporation 18 ha:s plural access mechanisms mounted on the exterior of a 19 cast metal shroud surrounding disk stack. However, the shroud dpp~rentl~ does not support the disk stack and spindle, 21 which appear to be suppor~ed from benea~h. Hence, the a2 shroud does not function as a base.
23 U. S. Patent 4,008,492 discloses a magnetic disk memory 24 device wberein a disk pack is enclosed in a shroud. The 2S shroud has a chamber to which air is su-pplied to cool the `26 disks to reduce the temperature gradien~ between componenls 27 wlthin the chamber. However, this arrangement does not 28 propose a solution tn the dynamic out-of-plane bending 29 prob7em with which applicant is also concerned. The disk file apparatus according to the present invention subs~an:-31 tially eliminates both dynamic and static out-of-plane 32 bending of the base.
. . ' ' 2 The disk file apparatus embodying the present invention 3 comprises a substantial1y symmetrical hollow generally ring-4 shaped base divided into two substantially identical parts
5 , by a neutral plane that passes through opposing symmetrical
6 walls thereof. A disk/spindle/housing assembly is inserted l axially within the hollow and mounted to the base so its 8 center of,gravity lies su~stantially in said pl:an-e. The g assembly carries the coil of at least one voice coil motor (VCM), the pole pieces of which are moved axially of ~he 11 coil, -then~secured to brackets on the base within the hollow.
12 If two YCMs ar-e used, they are arranged at diametrically 13 opposlte sides of the disk. The center of force of each 14 VCM is as close as possible to said plane to substantially' eliminate bending moments on the base during VCM actuation 16 of the heads. The ring base configuration maintains a 17 substantially uniform temperature differential between the 18 interior and exterior surfaces of the base. The disks are 19 mounted with their'planes vertical and parallel to the neutral plane so that the significant temperature gradient 21 will occur parallel to the planes of the disks.
22 ''Br~i'e`f-Desc!~e ~ e Draw~
23 FIGS 1, 2 and'3 ~re schematic dlagrams of a disk file ' 24 apparatus constructed in accordance with the teachings of 25 the prlor ~rt; -26 F~G-4 i~s l~ top schematic sectional view of a disk f le 27 -apparatus embodyi'ng the invention; and 28 ~ FIGS SA,B constitute an exploded perspective view of .
29 the~file apparatws embodiment of FIG 4, ~ ~ -4-.
.
' '' ', 1 Prel lnary Descriptlon - FIGS l, 2 and 3 2 These figures schematically depict a prior art-type 3 disk file apparatus which comprises a baseplate 10 connected 4 to a machine frame 11 through shock mounts, idealized as S springs 12. 8aseplate lO has secured to its upper-surface a 6 voice coil m.otor (VCM) 13. VCM 13 comprises a voice coil
12 If two YCMs ar-e used, they are arranged at diametrically 13 opposlte sides of the disk. The center of force of each 14 VCM is as close as possible to said plane to substantially' eliminate bending moments on the base during VCM actuation 16 of the heads. The ring base configuration maintains a 17 substantially uniform temperature differential between the 18 interior and exterior surfaces of the base. The disks are 19 mounted with their'planes vertical and parallel to the neutral plane so that the significant temperature gradient 21 will occur parallel to the planes of the disks.
22 ''Br~i'e`f-Desc!~e ~ e Draw~
23 FIGS 1, 2 and'3 ~re schematic dlagrams of a disk file ' 24 apparatus constructed in accordance with the teachings of 25 the prlor ~rt; -26 F~G-4 i~s l~ top schematic sectional view of a disk f le 27 -apparatus embodyi'ng the invention; and 28 ~ FIGS SA,B constitute an exploded perspective view of .
29 the~file apparatws embodiment of FIG 4, ~ ~ -4-.
.
' '' ', 1 Prel lnary Descriptlon - FIGS l, 2 and 3 2 These figures schematically depict a prior art-type 3 disk file apparatus which comprises a baseplate 10 connected 4 to a machine frame 11 through shock mounts, idealized as S springs 12. 8aseplate lO has secured to its upper-surface a 6 voice coil m.otor (VCM) 13. VCM 13 comprises a voice coil
7 13a that is connected to a carriage/arm assembly l4. Assembly
- 8 14 is movable translationally to carry magne~ic heads 15
9 into accessing transducing relation with a selected concentric
- 10 track on a particular one of a plurality of coaxially arranged lL magnetic disks 16. The pack of disks is rotatab1y mounted 12 adjacent one end of a spindle 17. The spindle is supported 13 adjacent its opposite end in bearings (not shown) carried by 14 baseplate 10.
As the carriage/arm assembly 14 seeks to different 16 tracks, reaction forces Fl (FIG 2) are created by and at the 17 .VCM 13. Since the neutral axis lOa of baseplate 10 is below 18 the point of application of ~orce Fl by a distance Yl, a 19 bending ~oment of magnitude FlYl is applied to the baseplate.
O~her bending moments are applied to baseplate 10 whenever 21 it accelerates in the radial direction due to the mass 22 centers.of VCM 13 and the disk/spindle assembly ~3 16,17 being above the neutral axis lOa. A force F2 acting 2~ at a di.stance~Y2 from the neutral axis lOa produces a 25 ~ woment F2Y2 on the baseplate lO. If~the appropriate seek length 26 and delay between seeks is o~tained so tha~ there is sigllif;cant 27 force applied to VCM 13 at the natural frequency of baseplate ~8 10, then out-of-plane bendin~ such as depicted in FIG 3 will 29 occur. This will cause the carriage/arm assembly 14 to t~lt relative to disks 16, resulting in off-track error between , ~
1 the heads 15 and disks. As earlier noted, a prlor art 2 approach to reducing this error is to make the baseplate 10 3 stiffer by increasing its th;ckness. However, th;s approach -4 is ine.fficient because it increases the weight and cost of the baseplate.
6 Another problem associated wi~h disk file apparatus of 7 this prior art type is static out-of-plane bending due to S temperature gradients between khe upper and lower surfacPs of 9 baseplate 10. Bending of this type causes thermal off-track errors because of the uneven heating and thermal distortion
As the carriage/arm assembly 14 seeks to different 16 tracks, reaction forces Fl (FIG 2) are created by and at the 17 .VCM 13. Since the neutral axis lOa of baseplate 10 is below 18 the point of application of ~orce Fl by a distance Yl, a 19 bending ~oment of magnitude FlYl is applied to the baseplate.
O~her bending moments are applied to baseplate 10 whenever 21 it accelerates in the radial direction due to the mass 22 centers.of VCM 13 and the disk/spindle assembly ~3 16,17 being above the neutral axis lOa. A force F2 acting 2~ at a di.stance~Y2 from the neutral axis lOa produces a 25 ~ woment F2Y2 on the baseplate lO. If~the appropriate seek length 26 and delay between seeks is o~tained so tha~ there is sigllif;cant 27 force applied to VCM 13 at the natural frequency of baseplate ~8 10, then out-of-plane bendin~ such as depicted in FIG 3 will 29 occur. This will cause the carriage/arm assembly 14 to t~lt relative to disks 16, resulting in off-track error between , ~
1 the heads 15 and disks. As earlier noted, a prlor art 2 approach to reducing this error is to make the baseplate 10 3 stiffer by increasing its th;ckness. However, th;s approach -4 is ine.fficient because it increases the weight and cost of the baseplate.
6 Another problem associated wi~h disk file apparatus of 7 this prior art type is static out-of-plane bending due to S temperature gradients between khe upper and lower surfacPs of 9 baseplate 10. Bending of this type causes thermal off-track errors because of the uneven heating and thermal distortion
11 o~ the baseplate. More specifically, the spinning d;sks 16
12 and voice coil 13a are major heat sources. They raise the
13 temperature inside the disk stack cover 18 above
14 that`of the ambient air, thus heating the upper surface of the basep7~ate 10. Because of the iarge amount o~ turbulence 16 inside the cover, the temperature difference between any two 17 points w;thin the cover is small relative to the temperature 18 dif~erential between the ambient air and air wi~hin the cover.
19 The bottom sur~ace.of the baseplate is typically exposed to 20 ~atmosphere or to the heating of power supplies, etc., which 2`1: lie below it in machi-ne frame 11. The resu1tant ~ertical 22: temperature gradient ac-ross basep1ate 10 causes 1t to bend 23 out of the pTane of the disks 16, similar to the distortion 24 shown in FIG 3, thus resulting in off-track error.
25~ ~ The bendlng problems just described are substantially 26 el iminat.ed in the disk rile apparatus embodying the pres~!nt 27 ~ invention and now to be descr;bed ~ 28 ~Description o~ Preferred Embod1ment - FIG~ 4 and 5 ` 29~ ~As illustrated schematically in FIG 4, the disk file 30 apparatus embo~ying the lnvention comprises a disk/spind1e/
housing assembly 31 includlng a plurality o~ parallel disks ., ~ , . .
., . . . . . .~ .
.
1 32 coaxially arranged in a stack 33. Thes-e disks have on 2 the;r opposite planar surfaces a magnetic material on which 3 digital data is recordable magnetically. The disks of stack 4 33 are secured to a hub 34 that is keyed to a spindle 35 suitably supported in axially spaced bearings 36 and driven 6- from an external source (not shown) by a pulley 37 outboard 7 of the bearings. Encircling disk stacks 33 is a housing 38 8 compris;ng a plurality of circumferentially spaced radially g e~tending stiffen;ng ribs 39.
Two sets a,b of magnetic heads 40 are provided, each ll for reading or writing magnetic indicia on a correspond;ng 12 a~ially spaced group of the disks 32. Each set of heads is 13 movable trans1at;onal1y by a respect;ve carriage/arm assembly 14 41 that carries a selected one of the heads into transducing engagement with a selected track on a particular disk 32.
16 The carriage/arm assembl;es 4] are preferably of the type 17 described in the aforementioned related patent application.
18 These assemblies 41 are disposed at diametri~ally opposite l9 side~s of the d~sk stack 33 and supported by, and moYable translationally relative to, disk/spindle/housing assembly 21 31. Connected to the end of each carriage/arm assembly 41 22 remote from the heads is an electrically conductive coil 42 2~ 0~ a corresponding linear actuator device, preferably a 24 voice coil motor^(VCM) 43.
Referring now to FIG 5A, each VCM 43 comprises a 26 stationary portion 44 including a pair of electromagnets 27 45a,b secured in c;rcumferent;ally spaced re1ation to a 28 front pole piece 46 and a central pole piece (not shown) 29 formed integrally with a circular rear plate 47. These pole p;eces are radlally separa~ed by an annular a~r gap (no~
1 shown). Axial movement of the corresponding coil 42, 2 carr;age/arm,assembly 41 and heads 40a or b is initiated in 3 conventional fashion by passing current through a se1ected 4 one of the coils.
Referring now to FIG 5B, the disk f;le apparatus also ~ comprises a substantially symmetr;cal ring-shaped base 50.
7 The base preferably is an integral casting that comprises 8 upper and lower ho~sing portions 51a,b that ;nclude opposing 9 ring or segment-shaped annular portions; and the outer ends of each annular port;on terminate in aligned straight portions.
11 The.straight portions of the upper portion 51a are parallel 12 ~o and spaced from'and at their outer ends joined to those 13 o~ lower portion 51b. Each housing portion 51a~b provides a 14 patr of brackets 52, 53 (only one set shown).
lS According ta important features of the inventi'on, and 1~ as illustrated in FIGS 5A,B, base 50 is divided ;nto sub-17 stantially identical halves by an imaginary neutral plane 18 54 that passes vertically through the opposing walls of 19 upper and lower housings 51a,b. The disk/spindle/housing 2Q assembly 31, carriage/arm assemblies 41, and coils 42 of VCMs 21 43 are moved as a unit in the direction of the spindle axis 22 into a hollow enclosure or ca~ity 56 defin,ed between the 23 upper and lower base portions 51a,b. The disk~spindle/housing 24 assembly 31 is then connected~ as by bolts, directly to pairs of bosses 57 in the upper and lower housings 51a~b, 26 respectively. The sta~tionary port1Ons 44 of each VCM 43 are 27 now moved into cavity 56 in a direct;on generally parallel 28 to~the ax;s of spindle 35 until outboard the correspond;n,g 29 coii 42i whereupon they are moved inwardly toward the spindle 30 ~ axis in~partially overlying concentric relation to the respective 31 coil and bol~ed to the appropriate bracket 52 or 53. The ` SA977005 , -8-.. , :.
~g~
1 stationary portions 44 of the two VCMs arè then bolted 2 directly to the brackets 52, 53, respectively. The assemblage 31, 3 41, 42, 44 is centered within CaYity 56 (i.e., equidistant 4 from the inner walls of housings 51a,b), the respective 5 '! stationary portions 44 being disposed between the parallel 6 straight portions of said housings.
7 The bosses 57 are so located axially in base 50 tha~
8 the center of gravity of disk/spindle/housing assembly 31, g including the structure 41, 42 associated therewith, is sub-stantially coincident with ~he neutral plane. Likewise, the 11 brackets 52, 53 are so located that the center of force of 12 the stationary portion 44 of each VCM 43 is as close as 13 possible, and prefèrably concident with, neutral plane 54.
It will be understood that where only one V~M is used, or where two VCMs are used to control heads that access 16 alt~rnate or the same d~sks, it is readily possible ~or the 17 center of force of each UCM 43 to lie in the neutral plane 18 54. However, if, as in the embodiment illustrated, two VCMs 19 43 are used to control accessing of different axial1y spaced sets of heads 40a,b, the centers of force of the VCMs may ~1 have to be offset slightly from the neu~ral plane; but, in 22 such event, the centers of force should be offset equal 23 minimal distances from the neutra1 plane.
24 The entire disk/spindle/housing assembly must have its center of gravity located at the neutral p1ane of ring b~se 26 ~50 to prevent inertial forces resultant~fro.m in-plane acneleration 27 of the base from creating bending moments and exciting out-28 of-plane bend~ng modes of the type earlier described in 29 connection wlth FIGS 1-3. Since the VCM reaction forces act either at or close to the neutral plane 54 and the inertial , ` , g 955~
1 forces of the d;sk~spindle/ housing assembly act through the 2 neutral'plane, dynamic out-of-plane bending is substantially 3 eliminated.
4 Static out-of-plane bending due to temperature gradients S is also substantially eliminated in the disk file apparatus 6 embodying the invention. It will be noted that the axis of 7 spindle 35 is horizon~al, so that the planes of the disks 8 are vertical. The significant temperature gradient thus 9 occurs parallel'to the planes of the disks (not out of plane as with the prior art configuration depicted in FIGS 1~3).
11 Since the~disk/spindle/housing assembly 31 is centered 12 within cavity 56 of the substantially symmetrical base 50, 13 and the walls of housing portions Sla,b above and below sa;d 14 assembly are of uniform thickness, a substantially uniform 1S temperature differential exists between the cavity and the ' ' 16 ambient air ~utside the base. The axial ends of base 50 are 17 enclosed by covers of plastic or light gauge'metai. These 18 covers are of such insign;ficant stiffness relative to that 19 of the base that the temperature gradients across them do ~o not cause the ring base to bend out of plane.
In summary, in the improved disk file apparatus embodying 22 the invention, dynamic bending of the base out of the plane 23 of the disks due to voice coil motor reaction'forces and 24 static ~ending of the base out of the plane of the disks due ' to temperature gradients are substantially eliminated. ~his 26 excludes d major cause of off~track errors, thereby enab'l;ng 27 a re~duction in allowablé track-to track spacing in the 28 respective disks. 'In addition, field replacement of the 29 disk/spindle/housing assembly 31 i5 facilitated~ since ~he assembly 31 and its associated movable structure 42, 419 40 -, " '', ' ' ~
1 can be removed axially as a unit after the relatively heavy 2 stat;onary portions 44 of the YCMs ~3 are removed by wi~h-3 drawal in diametrically opposed directions.
4 Wh;le the invention has been particular1y shown and S described with reference to a preferred embodiment thereof, 6 it will be understood by those skilled in the art that 7 various changes in form and detail may be made there;n 8 without departing from the spirit, scope and teaching of 9 the invention. Accordingly, the apparatus herein disclosed is to be considered merely as illustrative, and the invention 11 is to be llimited only as specified in the claims.
' . , : ' 19 , ' ' :
:
: 22 23:
24 ~ -~
- : , -2 7 :
-, ~, : 30 ~
~: : ' ' ' ' .. ,... ~ . . . . . .... .. . . . . .. .. . ... .. . . . .. ..
19 The bottom sur~ace.of the baseplate is typically exposed to 20 ~atmosphere or to the heating of power supplies, etc., which 2`1: lie below it in machi-ne frame 11. The resu1tant ~ertical 22: temperature gradient ac-ross basep1ate 10 causes 1t to bend 23 out of the pTane of the disks 16, similar to the distortion 24 shown in FIG 3, thus resulting in off-track error.
25~ ~ The bendlng problems just described are substantially 26 el iminat.ed in the disk rile apparatus embodying the pres~!nt 27 ~ invention and now to be descr;bed ~ 28 ~Description o~ Preferred Embod1ment - FIG~ 4 and 5 ` 29~ ~As illustrated schematically in FIG 4, the disk file 30 apparatus embo~ying the lnvention comprises a disk/spind1e/
housing assembly 31 includlng a plurality o~ parallel disks ., ~ , . .
., . . . . . .~ .
.
1 32 coaxially arranged in a stack 33. Thes-e disks have on 2 the;r opposite planar surfaces a magnetic material on which 3 digital data is recordable magnetically. The disks of stack 4 33 are secured to a hub 34 that is keyed to a spindle 35 suitably supported in axially spaced bearings 36 and driven 6- from an external source (not shown) by a pulley 37 outboard 7 of the bearings. Encircling disk stacks 33 is a housing 38 8 compris;ng a plurality of circumferentially spaced radially g e~tending stiffen;ng ribs 39.
Two sets a,b of magnetic heads 40 are provided, each ll for reading or writing magnetic indicia on a correspond;ng 12 a~ially spaced group of the disks 32. Each set of heads is 13 movable trans1at;onal1y by a respect;ve carriage/arm assembly 14 41 that carries a selected one of the heads into transducing engagement with a selected track on a particular disk 32.
16 The carriage/arm assembl;es 4] are preferably of the type 17 described in the aforementioned related patent application.
18 These assemblies 41 are disposed at diametri~ally opposite l9 side~s of the d~sk stack 33 and supported by, and moYable translationally relative to, disk/spindle/housing assembly 21 31. Connected to the end of each carriage/arm assembly 41 22 remote from the heads is an electrically conductive coil 42 2~ 0~ a corresponding linear actuator device, preferably a 24 voice coil motor^(VCM) 43.
Referring now to FIG 5A, each VCM 43 comprises a 26 stationary portion 44 including a pair of electromagnets 27 45a,b secured in c;rcumferent;ally spaced re1ation to a 28 front pole piece 46 and a central pole piece (not shown) 29 formed integrally with a circular rear plate 47. These pole p;eces are radlally separa~ed by an annular a~r gap (no~
1 shown). Axial movement of the corresponding coil 42, 2 carr;age/arm,assembly 41 and heads 40a or b is initiated in 3 conventional fashion by passing current through a se1ected 4 one of the coils.
Referring now to FIG 5B, the disk f;le apparatus also ~ comprises a substantially symmetr;cal ring-shaped base 50.
7 The base preferably is an integral casting that comprises 8 upper and lower ho~sing portions 51a,b that ;nclude opposing 9 ring or segment-shaped annular portions; and the outer ends of each annular port;on terminate in aligned straight portions.
11 The.straight portions of the upper portion 51a are parallel 12 ~o and spaced from'and at their outer ends joined to those 13 o~ lower portion 51b. Each housing portion 51a~b provides a 14 patr of brackets 52, 53 (only one set shown).
lS According ta important features of the inventi'on, and 1~ as illustrated in FIGS 5A,B, base 50 is divided ;nto sub-17 stantially identical halves by an imaginary neutral plane 18 54 that passes vertically through the opposing walls of 19 upper and lower housings 51a,b. The disk/spindle/housing 2Q assembly 31, carriage/arm assemblies 41, and coils 42 of VCMs 21 43 are moved as a unit in the direction of the spindle axis 22 into a hollow enclosure or ca~ity 56 defin,ed between the 23 upper and lower base portions 51a,b. The disk~spindle/housing 24 assembly 31 is then connected~ as by bolts, directly to pairs of bosses 57 in the upper and lower housings 51a~b, 26 respectively. The sta~tionary port1Ons 44 of each VCM 43 are 27 now moved into cavity 56 in a direct;on generally parallel 28 to~the ax;s of spindle 35 until outboard the correspond;n,g 29 coii 42i whereupon they are moved inwardly toward the spindle 30 ~ axis in~partially overlying concentric relation to the respective 31 coil and bol~ed to the appropriate bracket 52 or 53. The ` SA977005 , -8-.. , :.
~g~
1 stationary portions 44 of the two VCMs arè then bolted 2 directly to the brackets 52, 53, respectively. The assemblage 31, 3 41, 42, 44 is centered within CaYity 56 (i.e., equidistant 4 from the inner walls of housings 51a,b), the respective 5 '! stationary portions 44 being disposed between the parallel 6 straight portions of said housings.
7 The bosses 57 are so located axially in base 50 tha~
8 the center of gravity of disk/spindle/housing assembly 31, g including the structure 41, 42 associated therewith, is sub-stantially coincident with ~he neutral plane. Likewise, the 11 brackets 52, 53 are so located that the center of force of 12 the stationary portion 44 of each VCM 43 is as close as 13 possible, and prefèrably concident with, neutral plane 54.
It will be understood that where only one V~M is used, or where two VCMs are used to control heads that access 16 alt~rnate or the same d~sks, it is readily possible ~or the 17 center of force of each UCM 43 to lie in the neutral plane 18 54. However, if, as in the embodiment illustrated, two VCMs 19 43 are used to control accessing of different axial1y spaced sets of heads 40a,b, the centers of force of the VCMs may ~1 have to be offset slightly from the neu~ral plane; but, in 22 such event, the centers of force should be offset equal 23 minimal distances from the neutra1 plane.
24 The entire disk/spindle/housing assembly must have its center of gravity located at the neutral p1ane of ring b~se 26 ~50 to prevent inertial forces resultant~fro.m in-plane acneleration 27 of the base from creating bending moments and exciting out-28 of-plane bend~ng modes of the type earlier described in 29 connection wlth FIGS 1-3. Since the VCM reaction forces act either at or close to the neutral plane 54 and the inertial , ` , g 955~
1 forces of the d;sk~spindle/ housing assembly act through the 2 neutral'plane, dynamic out-of-plane bending is substantially 3 eliminated.
4 Static out-of-plane bending due to temperature gradients S is also substantially eliminated in the disk file apparatus 6 embodying the invention. It will be noted that the axis of 7 spindle 35 is horizon~al, so that the planes of the disks 8 are vertical. The significant temperature gradient thus 9 occurs parallel'to the planes of the disks (not out of plane as with the prior art configuration depicted in FIGS 1~3).
11 Since the~disk/spindle/housing assembly 31 is centered 12 within cavity 56 of the substantially symmetrical base 50, 13 and the walls of housing portions Sla,b above and below sa;d 14 assembly are of uniform thickness, a substantially uniform 1S temperature differential exists between the cavity and the ' ' 16 ambient air ~utside the base. The axial ends of base 50 are 17 enclosed by covers of plastic or light gauge'metai. These 18 covers are of such insign;ficant stiffness relative to that 19 of the base that the temperature gradients across them do ~o not cause the ring base to bend out of plane.
In summary, in the improved disk file apparatus embodying 22 the invention, dynamic bending of the base out of the plane 23 of the disks due to voice coil motor reaction'forces and 24 static ~ending of the base out of the plane of the disks due ' to temperature gradients are substantially eliminated. ~his 26 excludes d major cause of off~track errors, thereby enab'l;ng 27 a re~duction in allowablé track-to track spacing in the 28 respective disks. 'In addition, field replacement of the 29 disk/spindle/housing assembly 31 i5 facilitated~ since ~he assembly 31 and its associated movable structure 42, 419 40 -, " '', ' ' ~
1 can be removed axially as a unit after the relatively heavy 2 stat;onary portions 44 of the YCMs ~3 are removed by wi~h-3 drawal in diametrically opposed directions.
4 Wh;le the invention has been particular1y shown and S described with reference to a preferred embodiment thereof, 6 it will be understood by those skilled in the art that 7 various changes in form and detail may be made there;n 8 without departing from the spirit, scope and teaching of 9 the invention. Accordingly, the apparatus herein disclosed is to be considered merely as illustrative, and the invention 11 is to be llimited only as specified in the claims.
' . , : ' 19 , ' ' :
:
: 22 23:
24 ~ -~
- : , -2 7 :
-, ~, : 30 ~
~: : ' ' ' ' .. ,... ~ . . . . . .... .. . . . . .. .. . ... .. . . . .. ..
Claims (17)
1. A disk file apparatus of the type including an electro-magnetically controlled actuator device having a fixed portion and a movable portion translationally movable relative to and supported by a disk/housing assembly, characterized by:
a hollow base having a neutral plane extending through the center of opposing annular walls thereof, said base being adapted for mounting the disk/housing assembly therewithin with the center of gravity of said assembly substantially coincident with said neutral plane, and said base being further adapted for mounting the fixed portion of the actuator device directly thereto such that its center of gravity and center of force reaction is substantially coincident with said neutral plane.
a hollow base having a neutral plane extending through the center of opposing annular walls thereof, said base being adapted for mounting the disk/housing assembly therewithin with the center of gravity of said assembly substantially coincident with said neutral plane, and said base being further adapted for mounting the fixed portion of the actuator device directly thereto such that its center of gravity and center of force reaction is substantially coincident with said neutral plane.
2. In a disk file apparatus of the type comprising at least one voice coil motor (VCM), each including pole pieces of heavy mass and a relatively light electrically conductive coil axially movable relative to and supported by a disk/housing assembly, the combination of:
a substantially symmetrical hollow base having an imaginary neutral plane through opposing walls of sub-stantially identical halves thereof;
means for mounting the assembly to said base sub-stantially centered within the hollow and with its center of gravity substantially coincident with said plane; and means for mounting the VCM pole pieces directly to said base in such manner that the center of force of each VCM substantially coincides with said plane.
a substantially symmetrical hollow base having an imaginary neutral plane through opposing walls of sub-stantially identical halves thereof;
means for mounting the assembly to said base sub-stantially centered within the hollow and with its center of gravity substantially coincident with said plane; and means for mounting the VCM pole pieces directly to said base in such manner that the center of force of each VCM substantially coincides with said plane.
3. A disk file apparatus comprising, in combination:
a substantially symmetrical hollow base having an imaginary neutral plane through opposing walls of substan-tially identical parts thereof;
an assembly including at least one magnetic disk and means for supporting each such disk; and means mounting said assembly within and to said base such that the center of gravity of said assembly is disposed substantially coincident with said neutral plane and the axis of said assembly is normal to said plane and substan-tially centered between said opposing walls of said base for maintaining a substantially uniform temperature differential between the interior and exterior of said base.
a substantially symmetrical hollow base having an imaginary neutral plane through opposing walls of substan-tially identical parts thereof;
an assembly including at least one magnetic disk and means for supporting each such disk; and means mounting said assembly within and to said base such that the center of gravity of said assembly is disposed substantially coincident with said neutral plane and the axis of said assembly is normal to said plane and substan-tially centered between said opposing walls of said base for maintaining a substantially uniform temperature differential between the interior and exterior of said base.
4. An apparatus according to claim 3, characterized in that said assembly comprises a stack of magnetic disks mounted with the planes of the disks vertical and parallel to said neutral plane, such that the significant temperature gradient occurs parallel to the planes of said disks.
5. An apparatus according to claim 3, further comprising:
an electromagnetically controlled actuator device for controlling movement of at least one magnetic head, said device comprising a fixed portion mounted to said base and a movable portion carried by and movable relative to said assembly for moving the magnetic head in directions parallel to said plane for transducing engagement with said disk, the center of force of said fixed and movable portions lying substantially in said neutral plane to substantially eliminate any bending moments on said base during said translational movement of said movable portion.
an electromagnetically controlled actuator device for controlling movement of at least one magnetic head, said device comprising a fixed portion mounted to said base and a movable portion carried by and movable relative to said assembly for moving the magnetic head in directions parallel to said plane for transducing engagement with said disk, the center of force of said fixed and movable portions lying substantially in said neutral plane to substantially eliminate any bending moments on said base during said translational movement of said movable portion.
6. An apparatus according to claim 5, wherein said actuator device is a voice coil motor, said fixed portion thereof comprising pole pieces and the movable portion thereof comprising an electrically conductive coil.
7. An apparatus according to claim 5, wherein said fixed portion is removable in a direction parallel to said plane and said movable portion is thereafter removable in unison with said assembly in a direction generally normal to said plane.
8. A disk file apparatus comprising, in combination:
a base in the form of a substantially symmetrical hollow enclosure defined by substantially identical parts bisected by an imaginary neutral plane;
a disk/spindle/housing assembly including a plurality of magnetic disks disposed within a housing and rotatably driven by a spindle from externally of the housing;
means for mounting said assembly within said enclosure and to said base such that the center of gravity of said assembly is substantially coincident with said neutral plane and the axis of said spindle is normal to said plane and substantially centered between said parts of said base;
two sets of magnetic heads;
two electromagnetically controlled actuator devices, each comprising a fixed portion and a movable portion, one such device associated with each set of heads for moving the latter in directions parallel to said plane for transducing engagement with corresponding ones of said disks, means supporting each movable portion on said housing in substantially diametrically opposed relation outboard of said disks for movement radially thereof; and means securing said fixed portion to said base, such that their centers of force substantially coincide with said neutral plane to substantially eliminate any bending moments on the base resultant from translational movement of said movable portions.
a base in the form of a substantially symmetrical hollow enclosure defined by substantially identical parts bisected by an imaginary neutral plane;
a disk/spindle/housing assembly including a plurality of magnetic disks disposed within a housing and rotatably driven by a spindle from externally of the housing;
means for mounting said assembly within said enclosure and to said base such that the center of gravity of said assembly is substantially coincident with said neutral plane and the axis of said spindle is normal to said plane and substantially centered between said parts of said base;
two sets of magnetic heads;
two electromagnetically controlled actuator devices, each comprising a fixed portion and a movable portion, one such device associated with each set of heads for moving the latter in directions parallel to said plane for transducing engagement with corresponding ones of said disks, means supporting each movable portion on said housing in substantially diametrically opposed relation outboard of said disks for movement radially thereof; and means securing said fixed portion to said base, such that their centers of force substantially coincide with said neutral plane to substantially eliminate any bending moments on the base resultant from translational movement of said movable portions.
9. A disk file apparatus according to claim 8, wherein said sets of magnetic heads access different axially spaced groups of disks, and the centers of gravity and force of the respective actuator devices are offset substantially equal minimal distances to opposite sides of said neutral plane.
10. A method of making a disk file apparatus comprising the steps of:
providing a base in the form of a substantially symmetrical hollow enclosure having a neutral plane passing through the centers of substantially symmetrical opposing walls thereof;
mounting a disk/housing assembly and an associated movable structure including an electrically conductive coil of a voice coil motor, such that their centers of gravity are substantially coincident with said neutral plane and said assembly is substantially centered within said enclosure;
and mounting a stationary portion of the voice coil motor directly to said base with its center of force substantially coincident with said neutral plane, thereby to substantially eliminate bending moments on said base during movement of said movable structure and also maintain a substantially uniform temperature differential between the interior and exterior of said enclosure.
providing a base in the form of a substantially symmetrical hollow enclosure having a neutral plane passing through the centers of substantially symmetrical opposing walls thereof;
mounting a disk/housing assembly and an associated movable structure including an electrically conductive coil of a voice coil motor, such that their centers of gravity are substantially coincident with said neutral plane and said assembly is substantially centered within said enclosure;
and mounting a stationary portion of the voice coil motor directly to said base with its center of force substantially coincident with said neutral plane, thereby to substantially eliminate bending moments on said base during movement of said movable structure and also maintain a substantially uniform temperature differential between the interior and exterior of said enclosure.
11. A method according to claim 10, wherein in said mounting steps, the assembly is mounted by movement normal to said plane, and the fixed portion is mounted by movement parallel to said plane, such that the assembly and movable structure can be readily removed axially as a unit after lateral removal of the relatively heavy stationary portion.
12. A method of making a disk file apparatus comprising the steps of:
providing a substantially symmetrical hollow base having a neutral plane passing through the centers of opposing walls thereof;
mounting a disk/housing assembly, together with two associated movable structures disposed at diametrically opposite sides of said assembly but offset axially sub-stantially equal minimal distances from said neutral plane, within and to said base such that the center of gravity of said assembly with its associated movable structures is substantially coincident with said plane and substantially centered between said walls, each movable structure including a movable portion of a respective electromagnetically con-trolled actuator device which has a corresponding stationary portion; and mounting both stationary portions directly to said base with their respective centers of force also substantially coincident with said plane.
providing a substantially symmetrical hollow base having a neutral plane passing through the centers of opposing walls thereof;
mounting a disk/housing assembly, together with two associated movable structures disposed at diametrically opposite sides of said assembly but offset axially sub-stantially equal minimal distances from said neutral plane, within and to said base such that the center of gravity of said assembly with its associated movable structures is substantially coincident with said plane and substantially centered between said walls, each movable structure including a movable portion of a respective electromagnetically con-trolled actuator device which has a corresponding stationary portion; and mounting both stationary portions directly to said base with their respective centers of force also substantially coincident with said plane.
13. A method according to claim 12, wherein in said mounting steps, the assembly is mounted by movement normal to said plane, and each fixed portion is mounted by movement parallel to said plane but in opposing directions, such that the assembly and both movable structures can readily be removed axially as a unit after each rela-tively heavy stationary portion is removed by lateral withdrawal in opposing directions.
14. A subassembly for a disk file storage device comprising, in combination:
a base member;
a disk/housing assembly;
a pair of actuators each of which includes a stationary magnet structure and a coil movable relative to said magnet structure;
said disk/housing assembly comprising two sets of coaxially aligned magnetic disks, a shaft mounting each disk for rotation about a common axis, a pair of movable carriages, each carriage being associated with a respective one of the sets of disks, at least one transducer connected to each carriage for movement thereby into transducing engagement with at least one disk of the corresponding set, means for attaching each coil to a respective one of said carriages, and housing means mounting said shaft and said carriages so that said carriages move radially relative to said axis, said housing means being bisected by an imaginary neutral plane transversely of said axis into two essentially iden-tical halves;
means for removably attaching said housing means to said base member;
said base member having one portion providing a bore-like opening for receiving the disk/housing assembly and other portions each extending radially therefrom;
means for mounting said stationary magnet structures to said base member in substantially diametrically opposed relation relative to said disk/housing assembly but offset axially along said shaft equal minimal distances to either side of said neutral plane and in cooperative relationship with respective ones of said coils; and means mounting said disk/housing assembly to said base member to permit said coils to cooperate with said magnet structures to control movement of said carriages and thereby of said transducers.
a base member;
a disk/housing assembly;
a pair of actuators each of which includes a stationary magnet structure and a coil movable relative to said magnet structure;
said disk/housing assembly comprising two sets of coaxially aligned magnetic disks, a shaft mounting each disk for rotation about a common axis, a pair of movable carriages, each carriage being associated with a respective one of the sets of disks, at least one transducer connected to each carriage for movement thereby into transducing engagement with at least one disk of the corresponding set, means for attaching each coil to a respective one of said carriages, and housing means mounting said shaft and said carriages so that said carriages move radially relative to said axis, said housing means being bisected by an imaginary neutral plane transversely of said axis into two essentially iden-tical halves;
means for removably attaching said housing means to said base member;
said base member having one portion providing a bore-like opening for receiving the disk/housing assembly and other portions each extending radially therefrom;
means for mounting said stationary magnet structures to said base member in substantially diametrically opposed relation relative to said disk/housing assembly but offset axially along said shaft equal minimal distances to either side of said neutral plane and in cooperative relationship with respective ones of said coils; and means mounting said disk/housing assembly to said base member to permit said coils to cooperate with said magnet structures to control movement of said carriages and thereby of said transducers.
15. A subassembly for a disk file storage device com-prising, in combination:
a substantially symmetrical base member comprising two symmetrical housings of similar thickness and composition that include opposing segment-shaped annular portions provid-ing a cavity including a generally bore-like opening and at least one other portion extending radially therefrom;
a disk/housing assembly;
at least one actuator which includes a stationary magnet structure and a coil movable relative to said magnet structure;
said disk/housing assembly comprising at least one magnetic disk, a shaft mounting each disk for rotation about a hori-zontal axis, a movable carriage, at least one transducer connected to said carriage for movement thereby into transducing engagement with a cor-responding disk, means for attaching said coil to said carriage, and housing means mounting said shaft and said carriage so that said carriage moves radially relative to said axis;
means for removably attaching said housing means of said disk/housing assembly to said housing of said base member within said opening;
means for mounting said stationary magnet structure to said base member within said other cavity portion in sub-stantially radial relation to said disk/housing assembly and axis and in cooperative relationship with said coil; and means mounting said disk/housing assembly to said base member to permit said coil to cooperate with said magnet structure whereby static out-of-plane bending due to tempera-ture gradients is substantially eliminated because the symmetrical housings are of the same thickness and the significant temperature gradient occurs parallel to the plane of each disk.
a substantially symmetrical base member comprising two symmetrical housings of similar thickness and composition that include opposing segment-shaped annular portions provid-ing a cavity including a generally bore-like opening and at least one other portion extending radially therefrom;
a disk/housing assembly;
at least one actuator which includes a stationary magnet structure and a coil movable relative to said magnet structure;
said disk/housing assembly comprising at least one magnetic disk, a shaft mounting each disk for rotation about a hori-zontal axis, a movable carriage, at least one transducer connected to said carriage for movement thereby into transducing engagement with a cor-responding disk, means for attaching said coil to said carriage, and housing means mounting said shaft and said carriage so that said carriage moves radially relative to said axis;
means for removably attaching said housing means of said disk/housing assembly to said housing of said base member within said opening;
means for mounting said stationary magnet structure to said base member within said other cavity portion in sub-stantially radial relation to said disk/housing assembly and axis and in cooperative relationship with said coil; and means mounting said disk/housing assembly to said base member to permit said coil to cooperate with said magnet structure whereby static out-of-plane bending due to tempera-ture gradients is substantially eliminated because the symmetrical housings are of the same thickness and the significant temperature gradient occurs parallel to the plane of each disk.
16. A subassembly for a disk file storage device com-prising, in combination:
a substantially symmetrical base member comprising opposing annular housing portions of substantially identical thickness and composition which are substantially symmetri-cal with respect to an axis of symmetry and provide a sub-stantially symmetrical cavity therebetween, at least one voice coil motor, each comprising a stationary magnet structure and a coil movably associated therewith, a disk/housing assembly, means mounting said disk/housing assembly within the cavity and to said base member such that the axis of the disk/housing assembly coincides with the axis of symmetry of said housing portions, and the center of gravity of the disk/housing assembly is disposed along said axis of sym-metry at substantially the midpoint between opposite ends of said housing portions; and means mounting the stationary magnet structure of each voice coil motor within the cavity at substantially said midpoint of the housing portions and coaxially with each respective coil.
a substantially symmetrical base member comprising opposing annular housing portions of substantially identical thickness and composition which are substantially symmetri-cal with respect to an axis of symmetry and provide a sub-stantially symmetrical cavity therebetween, at least one voice coil motor, each comprising a stationary magnet structure and a coil movably associated therewith, a disk/housing assembly, means mounting said disk/housing assembly within the cavity and to said base member such that the axis of the disk/housing assembly coincides with the axis of symmetry of said housing portions, and the center of gravity of the disk/housing assembly is disposed along said axis of sym-metry at substantially the midpoint between opposite ends of said housing portions; and means mounting the stationary magnet structure of each voice coil motor within the cavity at substantially said midpoint of the housing portions and coaxially with each respective coil.
17. A subassembly for a disk file storage device com-prising in combination:
a base comprising opposing housing portions of sub-stantially identical thickness and composition which are substantially symmetrical with respect to an axis of sym-metry and provide a substantially symmetrical cavity there-between;
a disk/spindle/housing assembly including a plurality of rotatably driven magnetic disks;
means for mounting said disk/housing assembly within said cavity and to said base such that the axis of the disk/housing assembly coincides with the axis of symmetry and the center of gravity of the disk/housing assembly is disposed along said axis at substantially the midpoint between the opposite axial ends said housing portions; and two electromagnetically controlled actuator devices, each comprising a stationary magnet structure and a portion movable relative thereto, said movable portions being supported by said disk/
housing assembly in substantially diametrically opposed relation but offset equal minimal distances along said axis of symmetry to either side of said midpoint for movement radially of the disks for controlling transducing engagement with different disk surfaces, and said stationary magnet structures being mounted to said base such that their centers of force are substantially aligned with said midpoint to substantially eliminate any bending moments on the base resultant from translational movement of said movable portions.
a base comprising opposing housing portions of sub-stantially identical thickness and composition which are substantially symmetrical with respect to an axis of sym-metry and provide a substantially symmetrical cavity there-between;
a disk/spindle/housing assembly including a plurality of rotatably driven magnetic disks;
means for mounting said disk/housing assembly within said cavity and to said base such that the axis of the disk/housing assembly coincides with the axis of symmetry and the center of gravity of the disk/housing assembly is disposed along said axis at substantially the midpoint between the opposite axial ends said housing portions; and two electromagnetically controlled actuator devices, each comprising a stationary magnet structure and a portion movable relative thereto, said movable portions being supported by said disk/
housing assembly in substantially diametrically opposed relation but offset equal minimal distances along said axis of symmetry to either side of said midpoint for movement radially of the disks for controlling transducing engagement with different disk surfaces, and said stationary magnet structures being mounted to said base such that their centers of force are substantially aligned with said midpoint to substantially eliminate any bending moments on the base resultant from translational movement of said movable portions.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US83834677A | 1977-09-30 | 1977-09-30 | |
| US838,346 | 1977-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1109557A true CA1109557A (en) | 1981-09-22 |
Family
ID=25276871
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA304,089A Expired CA1109557A (en) | 1977-09-30 | 1978-05-25 | Disk file with symmetrical hollow base |
Country Status (17)
| Country | Link |
|---|---|
| JP (1) | JPS5455408A (en) |
| AR (1) | AR221066A1 (en) |
| BR (1) | BR7805656A (en) |
| CA (1) | CA1109557A (en) |
| CH (1) | CH629617A5 (en) |
| DE (1) | DE2830828A1 (en) |
| DK (1) | DK151739C (en) |
| FI (1) | FI67141C (en) |
| FR (1) | FR2404886A1 (en) |
| GB (1) | GB2005454B (en) |
| IE (1) | IE47039B1 (en) |
| IT (1) | IT1174388B (en) |
| NL (1) | NL7809812A (en) |
| NO (1) | NO150255C (en) |
| SE (1) | SE426112B (en) |
| SU (1) | SU921475A3 (en) |
| ZA (1) | ZA784308B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57191871A (en) * | 1981-05-22 | 1982-11-25 | Hitachi Ltd | Magnetic disk storing device |
| EP0222939B1 (en) * | 1985-10-31 | 1991-01-23 | International Business Machines Corporation | Disk file with in-hub motor |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3815150A (en) * | 1972-06-23 | 1974-06-04 | Memorex Corp | Flexible disc drive |
-
1978
- 1978-05-25 CA CA304,089A patent/CA1109557A/en not_active Expired
- 1978-07-12 FR FR7821340A patent/FR2404886A1/en active Granted
- 1978-07-13 DE DE19782830828 patent/DE2830828A1/en active Granted
- 1978-07-26 GB GB7831245A patent/GB2005454B/en not_active Expired
- 1978-07-28 ZA ZA784308A patent/ZA784308B/en unknown
- 1978-07-28 IE IE1537/78A patent/IE47039B1/en not_active IP Right Cessation
- 1978-08-10 CH CH851678A patent/CH629617A5/en not_active IP Right Cessation
- 1978-08-31 BR BR7805656A patent/BR7805656A/en unknown
- 1978-09-01 SE SE7809227A patent/SE426112B/en not_active IP Right Cessation
- 1978-09-07 IT IT27411/78A patent/IT1174388B/en active
- 1978-09-08 JP JP10987878A patent/JPS5455408A/en active Granted
- 1978-09-27 FI FI782943A patent/FI67141C/en not_active IP Right Cessation
- 1978-09-28 NO NO783288A patent/NO150255C/en unknown
- 1978-09-28 SU SU782670598A patent/SU921475A3/en active
- 1978-09-28 NL NL7809812A patent/NL7809812A/en not_active Application Discontinuation
- 1978-09-29 AR AR273894A patent/AR221066A1/en active
- 1978-09-29 DK DK432678A patent/DK151739C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| IE47039B1 (en) | 1983-11-30 |
| DK151739C (en) | 1988-06-13 |
| BR7805656A (en) | 1979-04-17 |
| IT7827411A0 (en) | 1978-09-07 |
| IE781537L (en) | 1979-03-30 |
| JPS5455408A (en) | 1979-05-02 |
| IT1174388B (en) | 1987-07-01 |
| DK432678A (en) | 1979-03-31 |
| GB2005454A (en) | 1979-04-19 |
| DE2830828C3 (en) | 1981-01-15 |
| GB2005454B (en) | 1982-02-10 |
| FR2404886B1 (en) | 1984-11-16 |
| NO783288L (en) | 1979-04-02 |
| ZA784308B (en) | 1980-02-27 |
| NO150255B (en) | 1984-06-04 |
| SE7809227L (en) | 1979-03-31 |
| NO150255C (en) | 1984-09-12 |
| DK151739B (en) | 1987-12-28 |
| SU921475A3 (en) | 1982-04-15 |
| FI67141C (en) | 1985-01-10 |
| NL7809812A (en) | 1979-04-03 |
| FR2404886A1 (en) | 1979-04-27 |
| FI782943A (en) | 1979-03-31 |
| DE2830828B2 (en) | 1980-05-08 |
| AR221066A1 (en) | 1980-12-30 |
| CH629617A5 (en) | 1982-04-30 |
| DE2830828A1 (en) | 1979-04-05 |
| FI67141B (en) | 1984-09-28 |
| SE426112B (en) | 1982-12-06 |
| JPS5756151B2 (en) | 1982-11-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2739472B2 (en) | Large capacity disk drive | |
| US5677813A (en) | Rotary information recording and reproduction apparatus | |
| US4743995A (en) | Disk file with in-hub motor | |
| US4190870A (en) | Disk drive assembly | |
| JPH02232881A (en) | Magnetic disc memory device | |
| US5189577A (en) | A magnetic disk apparatus and a motor securement therefor | |
| US5075808A (en) | Retaining clamp for a disc storage apparatus | |
| CA1068320A (en) | Multi-actuator system using single magnetic circuit | |
| US6538853B1 (en) | E-block having improved resonance characteristics and improved fragility | |
| JPH01243278A (en) | Magnetic disk device | |
| CA1109557A (en) | Disk file with symmetrical hollow base | |
| US4263629A (en) | Disk file with symmetrical hollow base | |
| US5854721A (en) | Balancing device of actuator in hard disk drive | |
| US4974104A (en) | Linear actuator disk file with symmetric housing | |
| KR0150438B1 (en) | Linear actuator for disc drive | |
| EP0462109B1 (en) | Shaft mounting for a disk file | |
| US5018035A (en) | Disc storage apparatus having an arcuate pivot assembly | |
| WO2000063888A2 (en) | Active magnetic bearing system for improved servo control | |
| JP2753533B2 (en) | Optical recording / reproducing device | |
| JPH03272062A (en) | Magnetic disk device | |
| AU593472B2 (en) | Thermal isolation of the voice coil motor from base plate and carriage guide rails of a disc drive | |
| CA1135408A (en) | Disk drive assembly | |
| JP3198444B2 (en) | Rotating disk storage device | |
| JP2001035099A (en) | Magnetic recorder | |
| JPH06251531A (en) | Magnetic disk device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |