US2207042A - Propeller control mechanism for adjustable and reversible pitch propellers - Google Patents

Description

y 1940- c. R. WASEIGE ,207,042

- PROPELLER CONTROL MECHANISM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS Original Filed April 25, 1935 6 Sheets-Sheet 1 I //P w #5 //5 July 9, Mil

' C. R. PROPELLER CONTROL MECHANISM FOR ADJUSTABLE WASEiGE AND REVERSIBLE PITCH PROPELLERS Original Filed April 25-, 1955 6 Sheets-Sheet W ND Q as m W awnMw 51mm.

July 9, 1940. c. R. wAsElGE PRO?ELLER 'CONTRQL MECHANISM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS Original Filed April 25, 1935 6 Sheets-Sheet 5 Ill/I C. R. WASEIGE PROPELLER CON 2,207,042 TROL MECHANISM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS Original Filed April 25 1935 Jul 9, 1940.

6 Sheets-Sheet 51 54 55 9 '56 56 y 1940- c. R. WASEI'GE 2,207,042

PROPELLER CONTROL MECHANISM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS 6 Sheets-Sheet 5 Original Filed April 25. 1935 Illa y 1940- c. R. \NASEEGE 2,207,042

- PROPELLER CONTROL MECHANISM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS Original File d April 25, 1935 6 Sheets-Sheet 6 Ill IIIIIIIIIIIIIIIIIIIIIIII CHARLES IBM Mama MAME/6'15 Attorneys.

Patented July 9, 1940 UNITED, STATE s PATENT OFFICE I PROPELLER CONTROL MEcnANIsM FOR ADJUSTABLE AND REVERSIBLE PITCH PROPELLERS Charles Raymond Waseige, Rueil', France 2 Claims.

My invention relates to airscrew propellers with variable and reversible pitch used on air crafts, of the type described and claimed in my co-pending application Serial No. 18,139, filed on 5 the 25th of April, 1935, of which the present application is divided out.

The'main object of my .invention is to provid connections between the pitch varying and re.- versing gear, its control means, the propeller driving engine and the control means of the latter, in order to make some of them dependent on the other or others in some predetermined occurrences Witha view to reduce as much as possible the attention required from the operations to 15 be made by the pilot.

This and other objects and advantages of my invention will appear thereafter from the description given below by way of example of two embodiments of my invention and this description 20 should be read with the understanding that the form, construction and arrangement of the several parts may be varied within the limits of the claims hereto appended, without departing from the spirit of the invention as expressed in said claims. It is for instance to be understood that while m invention will be fully described in detail with reference only to one particular type of propeller where the driving power required for this variation and reversal is furnished by the propeller driving engine, it is also applicable to aerial propellers with variable and reversible pitch of any other type where the driving power is furnished by the pilot or by an auxiliary motor, electric or other.

In the annexed drawings:

Fig. 1 is a diagrammatic view, showing a propeller with variable pitch, in which the mechanisms for slow variation and for pitch reversal comprise a common source of power and a speed- "-changing device.

Fig. 2 is a diagrammatic view of a propeller with variable pitch which emp1oys,.as a source of power for the variation of the pitch, the propeller 4 driving engine itself.

Fig. 3 is a partial diagrammatic view of a form of the controls which can be employed, chiefly in the case of the propeller shown in Fig. 2, as 'well as the connections between the controls.

Figs. 4a and 4b are similar to Fig. 3 but show' another part of the controls and'their connections.

Fig. 5 relates to a device for the automatic control of the mechanism for the slow variation of the speed.

tric motor- I which is supported in such way as to participate in the rotation of the propeller,

andit is thus supplied by means of conducting rings 2 which are coaxial with the propeller and work against fixed brushes, or inversely.

The said motor is connected with the propeller blades 4 by driving gear comprising a speedchanging device 5, which in this case is a speedchanging device having two ratios, of the type containing a secondary shaft H on which are keyed gear wheels Ill and H2 respectively in mesh with a gear wheel H3 keyed on the motor shaft H4 and with a gear wheel H loose on a shaft H6 .on which is secured a spur gear wheel 6 engaging a gear wheel 1 coaxial with the propeller and formed in one with a set of conical teeth 8 engaging conical teeth 9 mounted on the supports ll] of the blades on the shaft H6 is slidably keyed a clutch member lll adapted to alternately engage a cooperating clutch member H8 keyed on the motor shaft H4 or a, clutch member H9 secured to the gear wheel H5.

The control of'the speed-changing device 5 is effected by means of rod-and-link gear of any kind, comprising a member which is coaxial with the propeller and rotatable with. the latter, but which is movable lengthwise, and herein, this consists of a grooved ring ll co-operating with a member which is held against rotation but is movable lengthwise, in this case, a fork ii. A fork I20 engages the slidable clutch member Ill to alternately bring it into engagement with the clutch member H8 or H9.

The operating of the fork l2 will thus permit the use of either of the two ratios of transmission of the speed-changing device 5, thus affording a rapid change of pitch, which is preferably used for reversing the pitch, oron the,contrary, for a slow variation of the pitch, and the change of direction for the pitch variation can be obtained for instance by reversing the motor by means of a usual reversing switch under automatic or manual control.

The embodiment shown in Fig. 2 is a particular embodiment of pitch-varying mechanism comprising differential gearings adapted to be whose support can be coupled to or uncoupled braked by means of a servo-motor using fluid under pressure, such as oil.

Herein, there are mounted concentrically with the propeller shaft four drums I5, I6, I I, I8 which are loose on their bearings, and co-operate with brakes I9, 20, 2|, 22. The adjacent drums i1,l8 are connected together by a set of gearing having a negative ratio, 1. e., a gearing such that the from the propeller shaft, as to rotation, by means of any suitable clutch device 25, for instance of the tooth type; the said planetary pinion is engaged on the one hand with a set of teeth on the drum l6, and on the other hand with the drum H by means of a speed-reducing device which herein consists of a worm portion 26 located on the drum l1 and engaging a worm-wheel 21 keyed to v a shaft 28 which is at right angles to the propeller shaft and carries another worm 29 (see Fig. 4b) engaging a suitable wheel 30 keyed to the shaft of the said planetary pinion. The drums l5--l6 are also connected together We set of'gearing having a negative ratio, employing herein for this purpose a pinion 3i engaging external and internal sets of teeth located on the respective drums i5--|5, said pinion being keyed to a shaft 32 operating in bearings mounted on the casing of the propeller, thus rotating together with the latter. The movement of rotation of the pinion 3| on its axis is transmitted to the several blades by the shaft 32 and a mechanism to be further described.

It will be noted that when noneof the drums are braked, the whole of this mechanism will rotate as a unit together with the propeller shaft, .without any internal movement. If one of the drums i5 and I6 is braked, and if the support of the planetary pinion 24 is not secured, as to rotation, to the propeller shaft, the pinion 3! will rotate on its own axis, in one orthe other direction depending upon which one of the said drums is braked, and this will vary the pitch to a greater or less degree. On the other hand, the drums IT and I8 continue to operate with the same movement of rotation as the propeller, and the support of the planetary pinion 26 has the speed which is suitable for the conditions now prevailing.

When one of the drums |1l8 is braked, and when the support of the planetary pinion 24 has been connected, as to rotation, with the propeller shaft by means of the clutch 25, this sets up a relative movement (in one or the other direction, according to the drum which is braked) of the drum !6 and the support of the planetary pinion 24 and of the devices 21 to 30. Hence, through the medium of the speed-reducing parts 26 to 29, the planetary pinion 24 will turn on its own axis,

. in one or the other direction, and this movement the planetary pinion 24, will be usedfor the gradual variations of the pitch.

The movement of the pinion 3| itself and the movement of its shaft 32 may be-transmitted to the differentb-lades 4 by any suitable means. Herein, this transmission is advantageously obtained by the use of a pinion 34 which is mounted on the end of the shaft 32 and engages a gearwheel 35 coaxial with the propeller shaft, thus actuating an epicycloidal speed-reducing device comprising a planetary pinion rolling on a fixed base 36 concentric with the propeller shaft, mounted on an eccentric part 35a of the wheel 35 and having a second set of teeth 3611, also eccentric, which engages a set of teeth 31 coaxial with the propeller shaft and rotating together with a bevel pinion engaging a bevel gear 9 formed on the base of the propeller. This device is practically irreversible.

To actuate the pointer of the pitch indicator, not shown, there is provided herein a shaft 32 on which is keyed a gear wheel .43 in mesh with teeth provided on the drum It. The shaft 42 carries a conical gear wheel forming one sunwheel of adifierential mechanism it the other sun-wheel of which is driven from the propeller shaft through gear wheels 45. Shaft 52 is journaled in bearings internally carried by the stationary casing 46. The planet-carrier of the differential mechanism is secured on a shaft 41 connected to the pitch indicator. The gear wheels 45 are designed in order that the two sun wheels of the differential mechanism M are rotated at the same speed when the drum it rotates at the same speed as the propeller shaft, i. e., when none of the brakes I9 to 22 is applied; so that the planet-carrier and its shaft 41 remain motionless. As soon as a brake is applied and produces a relative rotation between this propeller shaft mechanism 44 are no longer rotated at the same speed so that the planet carrier will rotate at a speed depending upon that of this relative rotation and drives the pitch indicator.

Fig. 3 shows the hand lever 50 for controlling the pitch-reversing mechanism. This lever is connected by a rod 5!, or like connecting member, Figs; 3 and 4a with a device controlling servomotors 52 so arranged as to separately throw on the brakes l9 and 20. In Fig. 4a is represented two servo-motors, one being disclosed in detail and the other represented in outline form only to render the disclosure perfectly clear. Each servo-motor, (Fig. 4a) only one of which need be described, operates by fluid under pressure, and comprises for each brake a cylinder and a fluid distributing valve mechanism preferably adapted to supply fluid at full rate at all times except when completely cut off. For this purpose, the two valves 53 and 54 for admission and exhaust of the fluid are oppositely disposed and between their discs is located the end of a lever 55 mounted on a shaft 56 which carries two other levers 51 and 58 which are urged together by a spring 59. One of these levers, 58, is keyed to the shaft 56, the other lever beingloose between two stops secured to the shaft and situated on the respective sides of the extended part of the lever 58, and thus the lever 5'! will turn abruptly in one or the other direction under the action of the spring 59 when it proceeds beyond the said extended part. The two levers 51 are-connected together by rod-and-link gear or the like and thus the two valves 53 can be closed simultaneously, but only one of the valves can be opened at a time. Herein. the rod-and-link gear consists of a two-arm pivoting lever 60; to .one arm is pivoted a link 6| having a slot 62 in which is engaged a stud mounted on one of the levers, 51; to the other arm is pivoted a link 63, pivotally mounted on one arm of the rod 5|, which is bent at right angles, the other arm of the rod, which is pivoted to the said reversing lever 50 having a slot 64 in which is slidable a stud pertaining to the other lever 51. Thus the whole mechanism ,can have three definite positions, that is, a middle or neutral position in which both valves 53 are closed, and the two valves 54 open and two end positions in which one of the valves 53 is open whilst the other is closed.

In each cylinder 52 is accommodated a piston 52a to be urged against a return spring 5217 by the fluid pressure. Each piston rod. 52a extends out of the corresponding cylinder 52. and the outer rod portions are provided respectively with racks 52c, 52d in mesh with pivoted toothed sectors 52e, 52 connected through cranks 52g, 52h to ,the brakes I910, respectively, to actuate said brakes.

Consequently, when the hand-lever is moved either way from its neutral position, this will effect the abrupt opening of one of the valves 53, according to the direction of the displacement of the hand-lever, thus throwing on the corresponding brake. Theautomatic stopping of the reversal by the release of the brake is effected, in this apparatus, by means of two cams 65 and 66 corresponding to two predetermined values, positive and negative, of the pitch, said cams being positively operated by the mechanism of the pitch indicator, and one or the other cam, according to the position of the hand-lever 50, will act upon the lever 60 in order to bring the lever 51 of the valve 53 into a position of unstable equilibrium,

' beyond which the spring 59 will effect the instantaneous closing of said valve 53 and the opening of the valve 54, as well as the return of the rod-and-link gear and the reversing lever 50 into the neutral position herein represented, in which both valves 54 are open and the two brakes l9 and 20 are released.

Further the reversing lever 50 is herein connected with the device for the control of the supply of carburated mixture to the propeller driving engine through a'rod- 67 (Fig. 3) pivoted at one end to the said lever 59, and at the other end to a pivoting cam 58 which acts upon an articulated joint BE located between two rods T0ll. one of which, it, is connected with the engine throttle lflb and the other, ll. with the handlever .72 for the control of this throttle the joint 69 is made elastic by an elastic or resilient spring arranged to urge and hold the rods IO-H in a predetermined angular position. Said means may consist for instance in a rubber sleeve 690. the external face of which is adhered to the inner face of a metal sleeve 69b carried by one of the rods 70,1! while the inner faceof said rubber sleeve 69a is adhered to the external face of the stud 69c carried by the other of said rods l0, H. The connection between the rod 61 and the pivoted cam however provides for some lost motion in order that the cam will not turn when the hand-lever 5B is moved from its neutral position into the position corresponding to the positive value of the pitch. On the contrary, when the lever 50 is moved into its other position, the cam 68 is turned, and it thus moves the joint 69 when this is located on its path, which takes place for positions of the hand-lever" corresponding to a small opening of the engine throt tle. The movement of the joint 69 thuseflects an increased opening of the engine throttle without any displacement of the throttle control lever 12. When the lever 50 returns to its neutral position, the levers Ill-H return into the position shown in Fig. 3.

As the mechanism for the slow variation of the propeller pitch is also actuated, in this apparatus. by a servo-motor 15 using fluid under pressure, there is interposed in the conduit supplying the fluid under pressure, a valve 16 adapted for quick opening and closing, the mechanism for this purpose being, for instance, of the type of the mechanism 5'l-5859. This mechanism is controlled by a rod 11 urged by a spring 18, Fig. 3, in such way that the valve 16 will be continually urged toward open position, said rod ,being pivoted at the other end to a pivoted lever l9 located in the path of the cam said cam is connected with the throttle control lever 12, and its outline is such that the rod 11 will be maintained, against the action of the spring 18, in a position in which the valve Hi-is closed, whilst the hand-lever T2 is in the position in which the openingof the engine throttle is below a predetermined value.

In order to avoid all improper working, it is necessary that the mechanism for the slow variation of the pitch should not be actuated while the pitch-reversing mechanism is'in action. For this purpose, use may be made of a control device similar to the control of the mechanism for slow variation of the pitch, by the throttle lever, and it is preferable to employ a device, as herein represented. For this purpose, the lever 19 cooperates with. a cam 8| mounted on the reversing lever 50, and the outline of the cam is such that it is only when the lever 50 is in the neutral position that the lever 79 may be brought by the spring 78 into' the position corresponding to the opening of the valve l6.

Furthermore, in the construction shown in Fig. 2, it is necessary, in order that the reversing mechanism may operate, that the support of the planetary pinion 24 shall be released. For this purpose, a connection is made between the reversing lever 50 and the movable part of the clutch 25, and thus the displacement of the handlever 50 from its middle position will effect the release of the said support. Herein, this connection makes use of the said cam BI and the lever-l9 whose angular displacements are trans mitted by suitable rod-and-link gear 82, or like device, to a pivoted fork 83 which moves the said movable part lengthwise, by means of a-grooved collar 84 coaxial with the propeller shaft. The clutching, which might be effected by the pilot at will, is herein automatically efiected by the the slow'variation of the pitch, in such way that this mechanism cannot be actuated when the pitch has a negative value, is shown in Fig. 6, in which the control of the reversing mechanism is employed for this purpose. The cam 8|, which cuts out the mechanism for slow variation during the operating of the reversing mechanism, is herein divided into two parts am and Nb; the part 8la is provided on the hand-lever 50 to turn therewith, whilst the part Bib is connected with the same with a certain angular play or lost motion, for instance by a tenon 86 provided on the hand lever 50 and engaged in a groove Bl in the said member 8"). These various members are set in such a way that when the hand-lever 50 in its middle or neutral position as illustrated in Fig. 6 one side of the tenon 86 is in engagement with the right hand end of the groove 81 while the part 8"; is in a position allowing free operation of the mechanism for slow progressive variation of the pitch. When the control lever 50 is moved according to the arrow f (Fig. 6) from its neutral position into the position corresponding to the negative pitch, the tenon 86 will thus turn along with it thepart Nb of, the cam,

- gressive variation of the pitch is thereby brought which then bears upon the lever 19 and likewise as in Fig. 3 actuates the cut-out device E5 to I9, as well as the mechanism 82-85 which controls the clutch 25 and the mechanism for slow proout of operation. When the handle 50 returns to the neutral position, the tenon 86 will slide back in the groove 81 without moving the memher 8"), which thus continues to hold down the lever 19 and the left side of the tenon 86 comes 'hand lever 50 has now come into engagement with the lever I9 and holds down the latter so that the mechanism for the slow variation of the pitch remains kept out of action. When the hand-lever returns to the neutral position, the tenon 86 moves in the groove 87 without turning the cam piece Qlb which remains in its initial iosition but turned out of engagement with the lever 19 which is thus allowed to be swung upwards by the spring 18, whereby releasing the mechanism for the slow variation of the pitch as described above with reference to Fig. 3.

Fig. 3 also shows an example of the construction of a device adapted to prevent the racing of the engine when the propeller pitch comes to zero and when the engine throttle is well open.

For this purpose, the present apparatus comprises a rotating cam 88 connected by a suitable transmission means 861:, including a differential, with the mechanism 42 controlling the pitch indicator. The said cam actuates a lever 89 pivoting on a stationary axle 89a, and also pivoted to the rod-and-link gear '|li1ila controlling the engine throttle. It will be noted that the position of the lever 89 thus depends upon the position of the engine throttle, and when the latter is sufficiently closed, the cam 88 can rotate without meeting the lever 89 when the pitch passes through the zero value. On the contrary, when the throttle is well open, the lever 89 comes upon the path of the cam 88 and the cam willthus act upon the lever at the time when the pitch passes through the zero point, thus momentarily closing the engine throttle.

The same effect may be obtained by the cooperation of levers or cams mounted respectively on the throttle control lever and on the reversing lever, and adapted to act upon the throttle control in such way as to reduce the supply of carburated mixture to the engine for certain predetermined relative positions of the reversing lever and the throttle lever.

Fig. 5 shows a devicefor the automatic con-- trol of the mechanism for the slow variation of the pitch according to the engine speed. Herein,

the centrifugal governor 90 is driven by the englue and it controls the valve-gear of the servomotor 15 by means of the lever 9|. The tension of the spring 92 can be regulated while running, by the displacement of one of its supports consisting of a nut 93 mounted on a threaded rod 94 which can be rotated by suitable driving means, herein comprising the bevel gear wheels 95--96, the latter wheel being driven by the pinion 9'! engaging a rack 98 actuated by a retating cam 99- secured to a gear-wheel I00 engaging a like wheel I M rotatable by means of a hand-lever I02 together with a'pointer I03 moving over a dial I04 graduated in numbers of revolutions. Thus the displacement of the handlever I02 regulates the speed-of the engine by causing a variation of the pitch, and the governor 96 will then keep this speed automatically constant by suitably actuating the mechanism for the slow variation of the pitch according to the conditions of flight, whether on a level, or for riseor descent, or the like.

Fig. 5 also shows a form of construction of a device for limiting the possible variation of the propeller pitch to a range comprised between two extreme positive values. Said device herein consists of two stops I05 located on the path of the hand-lever I02, in such way that thislever cannot assume a position outside of the sector which is thus defined and which corresponds to engine 'speeds on either side of the normal working different positions of throttle lever 12, while stopping the action of the automatic mechanism for. the slow variation of the pitch.

Fig. 4b shows a form of construction of a hand control I ii] for bringing the propeller blades in line with the direction of the wind, in the case in which the oil pressure becomes reduced, or in case of other defective action. The said control H0 herein consists of a device of a known type operating by cable and acting directly upon a lever IH controlling a brake shoe 22, and when this latter is applied, it will cause a gradual reduction of the pitch.

The general operation of the devices above described is as follows:

When I move the control lever 50 from the position shown in Fig. '7 to the left to the position indicated by the sign I pull on the rod SI and move the latter to the left, whereby turning the lever 60 contrary to the clockwise direction and the lever 51 to the right through the medium of the lever 6|. The spring 59 then urges the lever 55 to turn contrary to the clockwise direction, whereby opening valve 53 and enabling valve 54 to be closed by its return spring. Fluid under pressure is thus admitted in the cylinder 52 and moves the piston 52a carrying the rack 520 which turns the sector 52e contrary to the clockwise direction and thereby applies the brake I!) through the crank 52g. The pitch reversing gear is thus set in operation and the pitch is rapidly reversed from a positive to a negative value, as above described with particular reference to Figs. 2, 3 and 4. It will be noted that during this movement of the rod 5i to the left the stud of the lever 57 of the servo-motor connected to the brake 20 slides idly in the slot 64 of the rod 5| so that this movement of the rod 5| is without effect on this servo-motor.

At the same time the displacement of the control'lever to the left produces a clockwise rotation of the pivoted cam 66 through the medium of the connecting rod 67 and in turn the cam 68 will stretch out the knee 69, whereby opening the throttle 10b through the rod Ill.

The operation of the pitch varying gear causes the shaft 67 to rotate as above described and the latter in turn rotates the cam 88 through the shaft 88a. This cam 88 will thus come into engagement with the lever 89 and turn it contrarily to the clockwise direction when the pitch is approaching the value zero. This rotation of 'the lever 89 is transmitted by the connecting rod 10a, to the throttle 70b which is thus brought to the position corresponding to the slow speed running of the engine, and the rod '10 is moved to the right. As the control lever 12 has not been moved and is held fixed this motion of the rod 16 will produce a bending of the knee 69 whatever may be the position of the cam 68 but as soon as the cam 88 releases the lever 89 this elastic joint 69 will resume its former position, whereby opening again the throttle 10b.

If'the lever 12 is initially in a position such that it holds the throttle 10b in the position of slow speed running of the engine, it will readily be understood that the lever 89 will be held by the connecting rod 10a out of the path of the cam 88.

The shaft 41 rotates also the cams 65, 66 cone nected to said indicator. At the same time where the pointer of the pitch indicator comes substantially in register with the mark on the dial, i. e., when the pitch has a predetermined negative value, the cam 65 comes into engagement with the pivoted lever 60 and swings it back to the position of Fig. '7, whereby pulling back the rod 5| and the control lever 50 to their initial neutral position, closing valve 53 and opening the exhaust valve 54. The return spring 52b will then move back the' piston 52a to its rest position, whereby releasing the brake l9 and stopping the operationof the pitch reversing When I move the control lever 50 to the right, I push on the rod 5i and operates the lever 51 directly pivoted to said rod; this lever 51 in turn operates the valves of the corresponding servomotor 52 in the same manner as above described with reference to the other servo-motor 52. The

latter remains inoperative since the link 6'! is moved to the left and the slot 62 slides on the corresponding lever 51 without actuating the latter. The brakes 20 are thus applied by the operating servo-motor 52'and the pitch value is reversed from a negative to a positive pitch value until the cam 66 rotated from the pitch indicator comes into engagement with the pivoted lever 60 and moves it back to its neutral position together with the link 5!, its associated'lever 59 and the control lever 50, whereby stopping the reversing gear. The operation of the cam 88 during this pitch reversal from a negative value to a positive value is exactly the same as during the inverse pitch reversal.

It will be noted that the motion-of the control lever 58 to the right does not operate the cam 68 owing to the lost motion connection between them.

I claim:

1. Control means for a variable pitch propeller provided with an automatic pitch varying mechanism adapted to slowly and progressively decrease and increase the pitch in dependence on the rotating speed of the propeller and. a pitch reversing mechanism adapted to far more rapidly reverse the pitch from a positive value to a negative value .and vice versa at the will of the pilot, said control means including means operable from the pilot to selectively cause operation of said mechanisms, means adapted to automatically control the fuel supply to the engine in dependence on the pitch value, and a further means adapted to vary the fuel supply and operatively connected to said means operable from the pilot to be actuated thereby.

2. Control means for a variable pitch propeller provided with an automatic pitch, varying mech-.

anism adapted to slowly and progressively decrease andincrease the pitch in dependence on the rotating speed of the propeller and a pitch of the latter and to said locking means in order that said locking means will lock the automatic pitch varying mechanism as long-as the pitch reversing mechanism is in operation.

' CHARLES RAYMOND WASEIGE.

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