US1717362A - Ribbon-feed mechanism - Google Patents

Description

June 18, 1929. J. H BARR.

RIBBON FEED uscnAnIsu Filed May 9, 1927 3 Sheets-Sheet ATTORNEY Ssl .5une18,1929. 1.717.362

mason FEED umcnamsu Filed May 9, 1927 5 Sheets-Sheet 2 hi1: Ii Ill 5 INVENTOR (75km li Barr ATTORNEY Jun 1929- J. H. BARR 1.711.362

RIBBON FEED uzcnlmlsu Filed May 9, 1927 3 Sheets-Sheet 3 INVENTOR $7M, H Belfr- ATTORNEY Patented June 18, 1929.

PATENT OFF'ICEL.

JOHN H. BARR, OF n'naoa, NEW YORK.

RIBBON-FEED MECHANISM.

Application filed May 9,

This invention relates to ribbon feed mechanisms for typewriters and similar printing devices, and has for its objects the production-of a simple and positive mechanism by which the ribbon is fed at each printing stroke, together with a quick acting automatic ribbon reverse mechanism operating on a single stroke of a key, and simple means for rewinding and changing ribbons. Other objects are to avoid unnecessary friction and binding, to prevent accidental displacement of the mechanism by vibration or driving forces, to make a construction which is read ily adapted to quantity production under modern manufacturing processes and in general to produce an eflicient and convenient device of the class described. Various other objects will become apparent as the description proceeds.

In the drawings forming part of this specification, 1

Fig. 1 is a plan view of the ribbon shift mechanism in one position of operation.

Fig. 2 is a similar plan View showing the feed shifted to the reverse position of opera tion.

Fig. 3 is a detail of the spool device and return release.

Fig. 4 is a view in elevation of the ribbon feed showing the ribbon shift mechanism,

and one ribbon spool assembly. 7 1

Fig. 5 is a detail in elevation of the yieldable detent bearing for the cross-shaft.

Fig. 6 is a detail view partly in cross-section on theline AA-of Fig. 5.

Fig. 7 is a detail plan view of aworm feed and cross-shaft bearing.

Fig. 8 is a plan view of the ribbon feed ratchet. i v Fig. 9 is an elevation of the same in one position of operation.

F 10 is a similar elevation in a second position of operation.

Similar reference numerals refer to the same parts thruout the various views.

Referring first to Fig. 1 and Fig. 2, the typewriter ribbon 1 is mounted to travel between two spools 2 and 2, on which it winds and unwinds as is usual in typewriters. Inasmuch as the present invention concerns improvements in the means for driving these spools :3 and Q, and for reversing the direction of travel when the end of the ribbon has 1927. Serial No. 189,890.

been reached, I will first describe the mech-, anism by which the spools are rotated, and then describe the means by which the direction of rotation of the spools is reversed when desired.

Referring now more especially to Fig. 4, the spool 2 is detachably mounted on the upper end of the shaft 3, so as to rotate therewith-the shaft 3 beingjournalled for rotation in the ears 4 and 5 of the supporting bracket 6. In order that the spool 2 and shaft 3 may not run too easily and overtravel, a compression spring 7 is mounted on the shaft 3 between the collar 8 and the bearing car 4-this spring 7 creating enough frictional drag on the shaft 3to keep the spools from unwinding too freely. The shaft 3 is driven thru a pair of cams or ratchets 3' which are carried on a hub secured to the lower end of the shaft 3, as shown for example in Fig. 3 and Fig. 4C. These cams 3 have an inclined face and a perpendicular face, and whenthe shaft 3 is being driven the perpendicular face is engaged by one of the spokes of the worm wheel 9, forming a positive drive. As shown for example in Fig. 3, it is desirable that the number of spokes of .the worm wheel 9 should differ from the number of cams o-r tceth ,3, so as to reduce the angular travel necessary for engagement. Variouscombinations of numbers of spokes and numbers of teeth may of course be used. The worm wheel 9 is loosely mounted on the shaft 3, and'free to slide vertically thereon until its hub strikes the lower side of the ear 5the clearance being sufficient to permit the spokes of the worm whel 9 to ride up over the tops of the inclined faces of the cams 8 if the spool shaft 3 is turned in the proper direction. This permits a rapid winding by turning tlio'spool 2 by hand, when changing a ribbon, as will be described. The spring 7 serves to hold the shaft 3 down in place, so that there is always sufficient clearance for the worm wheel 9 to ride up. The worm wheel 9 is'rotated by a worm 10, which. is mounted on a worm shaft 11, as clearly shown in Fig. 1 and Fig. 7. The worm shaft 11 extends across to ope ate the other spool 2 in a somewhat similar manner when the direction of ribbon feed is reversed, as will be described (see Fig. 2).

The cross shaft 11, at. about its middle point, (see Fig. 1) has a ratchet wheel 12 secured thereto, which is operated by a pawl 13 shown in Fig. 4, and also more in detail in Fig. 8, Fig. 9, and Fig. 10. The ratchet wheel 12 is substantially in the middleof the shaft 11, so as to be adjacent the pivot 32, in order that oscillations of the shaft 11 about the pivot 32 will not seriously affect the relation of the ratchet 12 to the pawl 13the ratchet merely shifting slightly sideways along the edge of the pawl tooth. The pawl 13 is yieldably attached to the link 14 by means of the pin 15 and spring 16, which holds the pawl 13 in contact with the ratchet 12, yet'permits the awl 13 to ride up on the return stroke, as

hown for example in Fig. 10. The link 14 is pivotally connected by the pin 17 to the ears 18 which are secured to and form art of the bail 19. This bail 19 extends su stantially across the machine and is pivoted at its ends in the bearings 20, about which it may swing when struck by a driving member, such as 21. Each of the printing keys of the typewriter is provided with a driving member 21 which is actuated whenever a printing key is pressed, so that whenever one of the keys is operated some one of the driving members 21 moves forward and strikes the bail 19. Any

' suitable key actuated drivin element may be used, for example as shown in my copending application, Serial No. 26,850, filed April 30, 1925, for typewriter, and as the particular form of the key action does not concern the present invention, it need not be described in further detail here.

The swinging bail 19 has attached thereto a tension spring 22, which serves to retract it after it has received the impulse of the driving member 21. The operation is clearly shown in Fig. 4, Fig. 9 and Fig. 10. Starting from the position shown in Fig. 9, the key actuated driving element 21 moves forward, strikes the bail 19, and swings it about the pivot 20 down to the position shown in Fig. 10. The pawl 13 engagin the ratchet 12 1'0- tates it in the direction 0 the arrow. Since the pivots 17 and 20 are approximately in the line of action at the start, a substantially harmonic motion results, that is, the initial linear motion of the pawl 13 is slow relative to the initial angular motion of the bail 19, but increases in speed as the motion progresses thus driving the ratchet 12 Without unneces sary shock. On the return motion, as the driving element 21 recedes, the sprin 22 retracts the bail 19, and the pawl 13 rides up and back over the teeth of the ratchet 12. A rod 24 may extend to the ribbon vibrator, if desired, so that it may also be operated by the bail 19. p

The rotation of the ratchet 12 as described is transmitted thru'the shaft 11 to the worm 10 andworm wheel 9, which rotates the shaft 3and spool 2 to feed the ribbon 1 along step by step as the keys of the typewriter are operated. It will be noted that by the construction described the ribbon is positively fed with each printing stroke but the ribbon is not moved when operating the space bar or in the traverse of the carriage 'by-hand. This permits the ribbon to be used-in a uniform and economical manner.

:I will now, describe the mechanism by which the direct-ion'of travel of the ribbon is automatically reversed, so that it may be alternately wound from one spool to the other, as long as desired, withoutattention on the part of the operator.

' Referring more particularly to Fig. 1 and Fig. 2, in which the bail 19 is only shown diagrammatically, and the ratchet driving pawl described is omitted for the sake of clearness, the frame 30 which supports the bearings 31, 31' of the cross-shaft 11, is mounted on a fixed pivot at 32 so that it may swing to a certain extent-permitting either one worm 10 or the other worm 10 to be brought into contact with their respective worm wheels 9 or 9. To induce this swing of the frame 30 at the proper time, a second'frame 33 is mounted so that it may slide on the frame 30, and shift thereon longitudinallyof the cross-shaft 11. This frame 33 has bearing ears 34 and 34 attached thereto, thru which pass the shaft 11- the shaft 11 being free to slide longitudinally therein as well as rotate.

Since the shaft 11 also passes thru the bearings 31, 31 of the frame 30, the frames 30 and 33 are thus connected together, with the frame 33 being slidable on the frame 30 in the direction of the shaft 11.

Two clips 35, 35, having hooks 36, 36 are slidably mounted on the cross-bar of the frame 33, being held against the stops 37, 37 by thev springs 38 and 38 respectively. At two points the bail-19 is provided with projections 40 and 40, whieh'are spaced apart somewhat differently from the books 36. .36' so that the projections 40 or 40 can only engage one book 36 or 36 at a time.

After the frame 33 has been shifted into the proper position, the hook 36 comes directly under the projection 40, and when the bail 19 is swung downward as has been described, the

projection 40 strikes the hook'36 and swings the frames 30 and-33 around the pivot 32 so as to withdraw the worm- 10 from engagementwith the worm wheel 9, that is, moving it from the position shown in Fig. 1 to that shown in Fig. 2. At the same timethe worm 10 is swung into engagement with the worm wheel 9'. Since the worms 10 and 10 have threads of opposite pitch, this serves to reverse the motion of the ribbon spools 2 and 2. The line of pull of the worm shaft. being somewhat ofiset from thepivot 32, helps to hold the worm in engagement.

It may sometimes happen that when one of the hooks 36, 36 is in the process of being shifted under one of the projections 40, 40 it may press against-the side ofthe projection I 19 from being. retracted by the spring 22. It

is to obviate this possibility that the hooks 36, 36' are mounted on slidable-clips retained by yielding springs 38 and 38, instead of being rigidly secured to the cross bar of the frame 33. If by chance one of the hooks 36, 36 bears against the side of the projection on the bail 19 and threatens to stop it, the amount of force the hook can bring to bear is limited by the spring 38 or 38, and this is proportioned so as to be insufficient to hold the bail 19 from returning.

Since only one impulse applied to the bail 19 is required to swing the frame 30 on the pivot 32, this shift operates on a single stroke of the typewriter key, after the frame 33 has been moved into the proper position relative to the projections on the bail 19. In order to shift the frame 33 into the proper position, a air of forked levers 42 and 42- are provi ed,engaging pins 43 and 43on the frame 33. These levers 42 and 42' are pivoted at 44 and 44' respectively, and the other ends of the levers extend up into the path of the ribbon 1,

and are provided with slots 45 and 45 re spectively thru which the ribbon passes. The ribbon 1 is provided with the usual clips 46 and 46near each end, and when the ribbon is substantially unwound from a spool, such as 2 in Fig. 1, the clip 46, being too large to pass thru the slot 45, carries the lever 42 along with the motionof the ribbon, and shifts the frame 33 in the direction of the spool 2. This brings the hook 36 under the projection so that when the bail 19 is swung down by the next stroke of a typewriter key, the worm 10' is swung out of mesh and the worm 10 is thrown into mesh, as shown in Fig. 1. Figs. 1 and 2 show the positionafter the automatic shift has been effected. The spool 2 then starts to wind up' the ribbon again. When the other end of the ribbon is-reached, the clip 46 operates the lever 42 in a similar manner, and shifts the worm 10' into driving engagement as shown in Fig. 2, thus reversing thetravel of the ribbon.

The levers 42 and 42' have extensions 47 and 47 respectively attached thereto, and connected by a light tension spring 48, which serves to return the frame 33 to its neutral or disengaged position, as soon as the shift has been accomplished and the ribbon begins to wind up, relievin the pressure of the ribbon clips 46 or 46 against the slot or 45. This keeps the hooks 36 and 36 normally out of line with the projections 40 and 40', so that they will not continually be struck by the swing of the bail 19.

In order to hold the shaft 11 in position after it has been shifted as described, it passes at its ends thru bearings 50 and 50', which are of the yieldable detent type, as shown more particularly in Fig. 4, Fig. 5, Fig.- 6, and Fig. 7, as well as Fig. 1 and Fig. 2. This bearing cient to hold the shaft 11 from displacement.

spools by hand, may

50 is made of two parts 51 and 52-as shown in Fig. 5, held together by the spring 53. The bearing parts 51 and 52 are relatlvely thin, so as to permit the shaft 11 to run in either of two non-parallel positions without binding. The part 51 is fixed to the supporting bracket 6, while the part 52 is pivoted at 54, and is provided with two recesses 55 and. 56, with a tongue or detent projection 57 sep-' arating them. When the shaft 11 is in one position it fits in the recess 56, and when the shaft 11 isshifted to the other position, as described, it fits in the recess 55. When it shifts from one position to the other, the pressure of the shaft 11 on the tongue 57'raises the bearing cap 52 against the force of the spring 53 and permits the shift. After the shift has been made,'the ton'gue 57 under the tension of the spring 53 is in general sufii- In changing ribbons it is desirable that both spools be permitted to turn freel so that the operator, by spinning one o the the ribbon all on one spool. One mechanism for permitting this free winding has been described, namely, the spokes of the wheels 9 or 9 being arranged to freely over-ride on the inclined faces of the cams 3. This al lows the spool whose worm wheel is locked 9 by the-worm to be wound up freely by hand (though it cannot be turned by hand in the opposite direction), while the other spool, whose worm wheel is not engaged with its worm, is of coursefree to spin in either di rection, and so. can .unwind its ribbon on to the winding spool. r 3

My construction also permits another method whereby both spools are released for free winding, if desired. The cross-shaft 11 projects slightly from each side of the machine, so that it can be reached by the operators finger, and if this shaft 11 is moved by hand to a position midway between its two normal positions, both of the worms 1'0 and 10 will be out of contact with their respective worm wheels 9 and 9, so that both worm wheels will be free to spin. When the shaft 11 is in this mid-position, it will be under the detent tooth 57 of Fig. 4 and Fig. 5. While the detent will have a tendency to move the shift into one or the other of its normal positions, the shaft is easily held by the hand. This construction also permits a hand reverse when desired, as the operator by the touch of a finger can throw the shaft 11 into the other detent notch and so reverse the ribbon.

In the foregoing I have explained and described a preferred form of my invention in certain specific examples, but it will be understood that these-are only by way of illustration, and that the apparatus is susceptible of various modifications and; adaptations'as will be apparent to those skilled in the art,

able to rapidly wind any one of said members, a ratchet wheel,

and a pawl pivoted to said bail and adapted to drive the ratchet wheel, the pivot of the pawl and the pivotal axis of the bail being substantially in the line of action of the pawl at the beginning of a driving stroke, whereby the starting shock is reduced.

2. In a ribbon feed mechanism, the combination of a cross-shaft mounted for rotation on its own axis and for oscillation about a transverse axis intermediate its ends, spool driving gears on opposite sides of the axis of oscillation, corresponding gears on the cross-shaft arranged to drive the spool gears in opposite directions and adapted to be brought alternately into driving engagement by oscillation of the cross-shaft, a supporting bearing for said shaft having two sockets and a yieldable detent projection between them, said bearing being proportioned so that said shaft may shift from one socket to a nonparallel positionin the other socket.

3. In a ribbon feed mechanism the combination of a s 001 shaft, a gear loosely mounted on said sha t for both rotary and axial motion, and a tooth mounted on said shaft and adapted to engage the gear, said tooth having a driving face and an overrunning face, whereby in one direction of rotation the gear will drive theshaft, and in theother direction of rotation the gear will over-ride the tooth and permit the shaft to turn freely.

4. In a ribbon feed mechanism, the combination of a spool shaft, a worm wheel loosely mounted on said shaft for both rotary and axial motion, a worm adapted to mesh with said worm wheel, and a tooth mounted on said shaft and adapted to engage the gear, said tooth having a driving face and an over-running face, whereby ino'ne direction of rotation the gear will drive the shaft, and in the other direction of rotation the gear will over-ridethe tooth and-permitthe shaft to turn freely. w

5. In aribbon feed mechanism, the combination of a spool shaft, a gear loosely'mounted on said shaft for both rotary and axial mo tion, said gear. having a plurality of spokes,

and a plurality of teeth mounted on said shaft and adapted to engage the spokes, the number of spokes differing from the number of teeth so as to reduce the angular travel necessary for engagement, said teeth having driving faces and over-running faces, whereby in one direction of rotation the gear will drive the shaft, and in the other direction of rotation the ear will over-ride the teeth andpermit the s aft to turn freely.

6. In a ribbon feed mechanism, the combination of a spool shaft, a. worm wheel loosely mounted on said shaft for both rotary and axial motion, said gear having a plurality of spokes, a worm adapted to mesh with said Worm wheel, and a plurality of teeth mounted on said shaft and adapted to engage thespokes the number of spokes differing from the number of teeth so as to reduce the angular travel necessary for engagement, said teeth having driving faces and over-running faces, whereby in one direction of rotation the gear willdrive the shaft, and in the other direction of rotation the gear will over-ride.

7 said movable member and said frame whereby the frame may be shifted on the single oscillation of the movable member, means for bringing said cooperating means into operative position, and means for withdrawing the cooperating means from operative position after reversal of the ribbon.

8. In a ribbon feed mechanism, the combination of a reversing frame mounted to swing about a pivot, a cross-shaft journalled in said frame, a shifting frame having bearings for said shaft relative to which the cross-shaft may both rotate for driving and move longitudinally for shifting, means for moving said shifting frame longitudinally on the cross-shaft, and actuating mean adapted to engage the shifting frame at either one of two points, whereby the shifting frame, shaft, and reversing frame may be swung about thepivot, and a ribbon feed mechanism arranged to be reversed thereby.

9. In a ribbon'feed mechanism, the combination of a reversing'frame mounted to swing about a pivot, a cross-shaft journalled in said frame, a shifting frame having bearings for said shaftrelative to which the crossshaft may both rotate for driving and move longitudinally for shifting, means for movingsaid shifting frame longitudinally on the cross-shaft, a pairofengaging means on said shifting frame capable of yielding in the line of shifting, actuating means adapted to on gage one or the other of said engaging means and move them transversely to the line of shifting, whereby the shifting frame, shaft, and reversing frame may be swung about the pivot, and a ribbon feed mechanism arranged to be reversed thereby.

10. In a ribbon feed mechanism, the combination of a reversing frame mounted to swing about a pivot, a cross-shaft journalled in said frame, a shifting frame having bearin s for said shaft relative to which the cross-s aft may both rotate for driving and move longitudinally for shifting, means for moving said shifting frame longitudinally on the cross-shaft, means for restoring the shifting frame to a neutral position, and actuating means adapted to engage the shifting frame at either one of two points, whereby the shifting frame, shaft, and reversing frame may be swung about the pivot, and a ribbon feed mechanism arranged to be reversed thereby.

. 11. In a ribbon feed mechanism, the combination of a reversing framemounted to swing about a pivot, a cross-shaft journalled in said frame, a shifting frame having bearings for said shaft relative to which the cross-shaft may both rotate for driving and move longitudinally for shifting, means for moving said shifting frame longitudinally on the cross-shaft, means for restoring the shifting frame to a neutral position, a pair of engaging means on said shifting frame capable of yielding in the line of shifting, actuating means adapted to engage one or the other of said engaging means and move them transversely to the line of shifting, whereby the shifting frame, shaft, and reversing frame may be swung about the pivot, and a ribbon feed mechanism arranged to be reversed thereby.

12. In a ribbon feed mechanism, the combi'nationof a pair of ribbon spools, a ribbon arranged to wind and unwind between them, clips near the ends of the ribbon, slotted levers'adapted to be moved by said clips, a shifting frame movable by said levers, bear-v ings carried by said shifting frame, a shaft mounted in said bearings for both rotary and axial relative motion, a second frame pivoted intermediate. the two spools, bearings for said shaft on said second frame, whereby the shifting frame, second frame, and shaft are interconnected for oscillatory motion about the pivot of the second frame, over-running clutch devices connected to drive said spools in opposite-directions alternatively, gear wheels adapted to rotate the clutch devices, two driving gears mounted on said shaft and'adapted to drive the gear wheels alternatively in opposite directions, a ratchet wheel mounted on said shaft intermediate the two driving gears, a 'ratchet drive mechanism for said ratchet, a pair of spaced engaging points on said shifting frame, a pair of differently spaced engaging elements having an oscillatory motion, whereby one or the other of said points on said shifting frame may be engaged when the frame is shifted, and the shaft swung about the pivot to engage one driving gear and disengage the other.

13. In a ribbon feed mechanism, the combination of a pair of ribbon spools, a ribbon arranged to wind and unwind between them, clips near the ends of the ribbon, slotted levers adapted to be moved by said clips, a shifting frame movable by said levers, bearings carried by said shifting frame, a shaft mounted in said beari'ngs for both rotary and axial relative motion, a second frame pivoted intermediate the two spools, bearings for said shaft on said second frame, whereby the shifting'frame, second frame, and shaft are interconnected for oscillatory motion about the pivot ofthe second frame, means to steady said shaft in one or the other of its shifted positions, over-running clutch devices connected to drive said spools in opposite directions alternatively, gear wheels adapted to rotate the clutch devices, two driving gears mounted on said shaft and adapted to drive the gear wheels alternatively in opposite directions, a ratchet wheel mounted on said shaft intermediate the two driving gears, a ratchet "drive mechanism for said ratchet, a pair of spaced engaging points on said shifting frame, a pair of differently spaced engaging elements having an oscillatory motion, whereby one or the other of said points on said shifting frame may be engaged when the frame is shifted, and the shaft swung about the pivot to engage one driving gear and disengage the other.

14. In a ribbon feed mechanism, the combi-" nation of a pair of ribbon spools, a ribbon arranged to wind and unwind between them, clips near the ends of the ribbon, slotted levers adapted to be moved by said clips, a shifting frame movable by said levers, means for restoring said shifting frame to a neutral position, bearings carried by said shifting frame, a shaft mounted in said bearings for both rotary and axial relative motion, a second frame pivoted intermediate the two spools, bearings for said shaft on said second frame, whereby the shifting frame, second frame, and shaft are interconnected for oscillatory motion about the pivot of the second frame, over-running clutch devices connected to drive said spools in opposite directions at ternatively, gear Wheels adapted to rotate the clutch devices, two driving gears mounted on said shaft and adapted to drive the gear wheels alternatively in opposite directions, a

ratchet wheel mounted on said shaft intermediatethe two driving ears, a ratchet drive mechanism for said ratchet, a pair of spaced engaging points on said shifting frame, a pair ofdiiferently spaced engaging elements having an oscillatory motion, whereb one or the adapted to be moved by said cli s, a shifting frame movable by said levers, earings carried by said shifting frame, a shaft mounted in said bearings for both rotary and axial relative motion, a second frame pivoted intermediate the two spools, bearings for said shaft on said second frame, whereby the shiftingframe, second frame, and shaft are interconnected for oscillatory motion about the pivot of the second frame, over-running clutch devices connected to drive said spools in opposite directions alternatively, gear wheels adapted to rotate the clutch devices, two driving gears mounted on said shaft and adapted to drive the gear wheels alternatively in opposite directions, a ratchet wheel mounted on said shaft intermediate the two driving gears, a ratchet drive mechanism for said ratchet, a pair of spaced engaging points on said shifting frame, a pair of differently spaced engaging elements having an oscillatory motion, whereby one or the other of said points on said shifting frame may be engaged when the frame is shifted, and the shaft L swung about the pivot to engage one driving gear and disengage the other, and yieldable means to limit the friction of said engaging points and engaging elements when the shifting frame is being moved into operative'engagement.

16. In a ribbon feed mechanism, the combination of a pair of ribbon spools, a ribbon arranged to wind and unwind between them, clips near the ends of the ribbon, slotted levers adapted to be moved by said clips, a shifting frame movable by said levers, means for restoring said shiftingv frame to a neutral position, bearings carried by said shifting frame, a'shaft mounted in said bearings for both rotary and axial relative motion, a second frame pivoted intermediate the two spools, bearin s for said shaft on said second frame, whereby the shifting frame, second frame, and shaft are interconnected for oscillatory motion about the pivot of the second frame, means to steady said shaft in one or the other of its shifted positions, over-running clutch devices connected to drive said spools in opposite directions alternatively, gear wheels adapted to rotate the clutch devices, two driving gears mounted on said shaft and adapted to drive the gear wheels alternatively in opposite directions, a ratchet wheel mounted on said shaft intermediate the two driving gears, a ratchet drive mechanism for said ratchet, a air of spaced engaging points on said shifting frame, a pair of differently spaced engaging elements having an oscillatory motion, whereby one or the other of said points on said shifting frame may be engaged when the frame is shifted, and the shaft swung about the pivot to engage one driving gear and disengage the other.

In testimony whereof, I have hereunto signed my name this sixth day of May, 1927.

JOHN H. BARR.

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