US1532368A - Fuse - Google Patents

Description

April 7, 1925. 1,532,368

F. w. BOLD FUSE Original Filed Oct. 31, 1919 2 Sheets-Sheet 1 Fig.3. Eiyi.

A m 5 5 Q/ a a as April 7, 1925.

F. w. BOLD FUSE Original Filed 060%1919 6g 6 2 Sheets-Sheet 2 Patented Apr. 7, 1925.

UNITED STATES PATENT QFFICE.

FREDRICK W. BOLD, OF CHELSEA, MASSACHUSETTS, ASSIGNOR TO CHARLES H. PEARSON, OF BR OOKLINE, MASSACHUSETTS.

rusza Application filed October 31, 1919, Serial No. 334,849. Renewed July 1, 1924.,

To all whom it may concern:

Be it known that I, FREDRICK W. BOLD, a citizen of the United States, and resident of Chelsea, in the county of Suffolk and State of Massachusetts, have invented an Improvement in Fuses, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My present invention relates to mechanical time fuses, and more particularly to mechanical time fuses adapted to be applied to ordnance shells for the purposev of deto nating the charge therein after a predetermined length of time following the discharge of the shell from .a gun.

In fuses of this character, no great difiiculty has been experienced in the past in satisfactory, must be safe to handle with thedevising means to positively detonate the charge in the shell. Considerable difliculty, however, has been experienced indevising means that will admit of the charge being detonated at exactly the right time, that is, means that will. detonate the charge when, and only when, it should be detonated. In other words, a mechanical time fuse, to be assurance that nothing short of its discharge from a gun, or by dropping it from such a distance that the shock on impact will be equal to its discharge from a gun, or an equivalent shock, will place the mechanism of the fuse in operative position, or in condition to detonate the charge of the shell to which it may be attached.

Mechanical time fuses of this character must be strong enough mechanically to withstand the shock of'discharge and the tremendous centrifugal forces set up by the rotation of the shell after discharge. That such strength is essential will be obvious when it is understood that the shock of discharge is so great that it is generally accepted that the inertia of "each grain of weight of the fuse becomes equal to approximately two pounds; that is, the apparent weight of the fuse is equal to its actual weight multiplied some fourteen thousand times. The centrifugal force set up by the rotation of the shell is such that at a distance of 'approximatel five-eighths of an inch from the axis 0 the fuse such centrifugal force is approximately equal to the force due to the shock of firing. Notwithstanding the tremendous forces set up by the shock of firing and the rotation of the shell, the moving parts of the timingmechanism should run accurately withinvthe one-hundredth part of a second, since with a velocity of more than a thousand feet per second, an error in the timing of the fuse may make a tremendous difference in the results attained. The carrying, or what may be termed the stationary parts of the fuse, must be therefore, of such ri id character as to be immune from the e ects of both shock and centrifugal force, while the moving elements, such as the time train and escapement, must be light in weight to run freely and without binding, as must also the firing pin and release mechanism therefor.

As a time fuse, when attached to a shell, has its time train always in operative condition, it is essential that means be provided to prevent accidental starting of such time train, with the resulting disastrous effects, until the desired predetermined length of time after such' starting.

An object of my present invention therefore, is the provision of means associated with the time train, to prevent the starting of the timing train until the fuse has been subjected to the shock of firing.

As however, a shell with a fuse attached, may be subjected to a shock, other than the shock of firing, and which shock may be equal to the shock of firing, it is essential for safety that an additional safeguard he provided that will prevent premature detonation of the charge of the shell because of such accidental shock.

Another object of my'invention, therefore, is the provision of means that will positively prevent premature detonation of the charge of the shell because of'shock other than that caused by the firing of the shell from the gun.

In carrying out the above object, I provide a spring pressed pivotally mounted shutter or plate in the path of movement of the firing pin, which plate is retained in position to prevent. axial movement of the firing pin until the centrifugal force generated by the shell in its rotation exceeds a predetermined amount. This amount is determined by a proper proportioning of the spring used to retain the plate in its tween the firing pin and the primer, and

associated" with said means a device which must be subjected to substantially the equivalent of the shock of firing before the means above referred to can be rotated to expose the primer to the action of the firing pin.

A further object of my invention, is the provisionof means associated with a centrifugally operated safety device interposed in the path of movement of the firing pin, for positively preventing the premature discharge of the shell due to accidents in handling and shipping.

As stated above, the time train of the fuse is always in operative condition; thatis,

the driving mechanism, usually, a spring, is

wound up, and the time train is started by the shock of firing. The timeatwhich the charge of the shell is detonated after the shell is fired from the gun varies with the range of the object fired at, so that usually this time interval is determined j'ust prior to the insertion of the shell in the gun, and in accordance with the range given-by the men in charge of "the range finder. Means must be provided therefore, for accurately determining this time interval, and it is usual to provide a graduated rotatable setting cap or head on thefuse block, geared to a rotatable plate on the time train. Various expedients have been employed for gearing the cap to the rotatable plate, and also for gearing the rotatable plate to the time train, none of which have been entirely satisfactory.

A further object of my invention therefore, is the provision of improved means for gearing the cap or head of the fuse to the rotatable plate on the time train that will positively couple these two elements -to-.

gether to set the time train to release the firing pin after a predetermined length of time, and which will operate to positively release said plate from the cap or head un der the shock of firing.

In carrying out this last named object, I provide a spring attached at one end to the interior of the setting capor head, with the free end of such spring under tension and always tending to move against the interior of said ca or head into position to release the rotata leplate. Slidably mounted on said spring. is a weight which engages with the interior of the cap or head and holds the free end of the spring in engagement' with the rotatable plate on the time train. A notch in the spring ordinarily prevents movement of said weight towards the free end of the spring, the force of the shock of firing, however, being great enough to cause said weight to move past the notch and into position, and to be held there, to allow the spring to release the retatable plate.

A still further object of my invention is the provision of means for positively connecting the rotatable plate with the timing train simultaneously with its release bythe spring above mentioned.

In carrying out this object, I attach said plate positively to the center staff of the time train, which staff is made tapering for' a portion intermediate its ends. On this tapered portion I mount the hub ofone of the gears of the time train, this mounting being such that the staff may be freely rotated during the setting of the time interval as above described, While providing a positive means for locking the staff and hub together by the shock of firing.

The setting of the timing train is a delicate and important operation, and in order that the best results may be obtained, I have provided improved means for mounting the setting cap or head on the fuse block in such a way that the power required to turn said cap may be varied to suit the convenience of theoperator. To this end I provide a circumferential groove in the fuse block and mount therein a spring ring over which the cap or head may be forced, and vary the tension of said spring ring by a screw or screws passing through the cap or head and engaging with the spring ring.

As it is frequently necessary to reset the timing mechanism, and as this operation has always been attended with great risk, owing to the fact that the notch in the setting plate or disc is'moved in this operation, into registry with the release lever of the trigger, I have so devised the setting spring in the setting capthat the tooth on the setting spring entirely blocks the notch and absolutely pxrevents the entrance of the release lever. y this means, the timing mechanism may be set and reset repeatedly without danger. a

O-her novel features of construction and arrangement of parts will appear as the description of the invention progresses.

In the accompanying drawings illustrating the preferred embodiment of my invention,

Fig. 1 is an elevation;

Fig. 2. is a sectional elevation;

Fig. 3 is a plan view of the fuse block on the line 3--3 of Fig. 2 showing the construcbut vice

. of the clock train startin Fig. 4 is a plan view showing the timing disc and associated mechanism in position on the-fuse block;

Fig. 5 is a detail showing the construction of the connection between the stafl and the hub of the timing train;

Fig. 6 is a sectional plan view, taken on the line 6-6 of Fig. 2;

Fig. 7 is a sectional plan view, taken on the line 7-7 of Fig. 2;

Fig. 8 is a sectional plan view, taken on the line 88 of Fig. 2;

Fig. 9 is a fragmentary side elevation of the timing train, taken on the line 99 of Fig. 4;

Fig. 10 is a detail taken on the line 10- 10 of Fig. 9;

Fig. 11 is a detail showing a modification mechanism; and

Fig. 12 is an enlarged detail showing the modification of the clock train starting mechanism illustrated in'Fig. 11.

Fig. 13 is an enlarged sectional detail, showing the construction and arrangement of the positive lock for the pivotedsafety plate.

Referring to the drawings, 10 designates the fuse block, providedwith exterior threads 11 by means of which it may be attached to a shell, and with a priming chamber 12 on its lower end, this chamber being closed by the screw plate 13. A passage 14 extends from the priming chamber 12 to a depression 15, located in the upper portion of the fuse block 10 and in which is placed the primer 16. The upper face of the fuse block is recessed at 17 to receive the lower plate 18 of the clock or timing movement 19. Screws 20 hold the movement firmly in position in such recess. A portion of the bottom face of the recess 17 is cut away to form a' chamber 21 exposing the upper portion of the depression 15, in which is located the primer 16. Pivotally mounted on the lower face of the chamber 21 is a plate or shutter 22, held in normal position, or in the position to cover the depression 15, by a spring 23 secured in the chamber -21 by the screw 24. Referring particularly to Figs. 3 and 13, 81 designates a hole in the base 10, said hole being parallel to and spaced apart from the passage 14. The lower end of this hole81 is tapered as shown, to correspondwith. the taper 86 on the lower end of the pin 85 which pin has afree sliding fit in the hole 81. The upper end of the'hole 81 is counterbored or re cessed at 82. The pin 85 is provided, near its upper end, with the circumferential groove 87 in whichis fitted a'spring ring 88, this ring bearing against the bottom of the counterbored portion 82 and normally hol'din the upper end of the pin 85 in the path of movement of the pivotally mounted plate or shutter 22, as clearly shown in Fig.-

lock or stop for the pivoted plate, preventing said plate from being moved to expose the primer 16 until after the pin 85 is moved downward into the hole 81. As this can only occur when the shell is subjected to the shock of firin the pin is an absolute safety device, and tl re shell may be handled. with impunity. When the shell is fired, the pin 85 is forced into the hole 81, the spring pin in this movement being forced upward on the pin, and the taper end 86 of the pin wedges into the taper of the hole 81, looking the pin 85 out of the path or rotation of the plate 22.

The clock or timing movement 19 ,comprises the bottom plate 18, middle plate 25, and top plate 26, spaced apart from each other by a plurality of pillars 27 and 28 respectively, and a cover plate 29 is secured to the top plate 26. The center staff 30 is mounted in bearings in the middle-plate 25 and cover plate 29, and the intermediate portion of the staff is tapered, as clearly shown in Fig. 5. Mounted on the tapered portion of the staff, and ordinarily rotatable with respect thereto, is a hub 3d, at the bottom of which is staked, or otherwise secured, a gear wheel 35 meshing with a pinion 135 associated with the portion of the timing gearing located below the-middle plate 25. As the construction and arrangement of such portion of the timing gearing forms no part ofthe present invention, it will not be described in detail herein. On the hub 34 and above the gear wheel 35 is staked an arm or release lever 33, which extends laterally from the hub and is rotatable therewith, the end of the arm in its rotative movement engaging, ordinarily, with the free Weighted end of the stop 32 riveted, or otherwise secured to the bottom of the top plate 26.

The top plate 26 is recessed at 36 to provide a chamber for the driving spring 39 of the timing mechanism, and the upper portion of the hub 34 is squared or otherwise machined out of round to provide a holding means for the non-cylindrical passage in the inner spring bearing 38. The inner end of the volute spring 39 'is attached to the bearing 38, while the outer end is attached tothe annular ring 40, the lower end of which, together with the spring 39, fits into the recess 36. The upper outer periphery of the ring 40 is provided wit-h gear teeth 141 and by'means of which the'spring is wound up, a suitable tool being used in connection therewith for this purpose. Pivotally mounted on the upper face of the top plate 26 is an improved spring pawl 75, the cover plate 29 being cut away, as shown in Fig. 7, to form a housing therefor. The cut away portion of the cover plate 29 is so proportioned with respect to the pawl with the center staff 30, the action of cen- 1 trifugal force acting on the pawl as theshell is rotated, is reducedto a minimum. 'Further, there is no danger of the pawl breaking and releasing the driving spring 39 un-' der the centrifugal force exerted by the .shell in its rotation as the working tooth of the pawl is supported throughout practically its entire length by the cut away portion of the cover plate 29.

Staked to the upper end of the staff is a setting plate 62, provided on its periphery with a notch 67 into which the extension 68 of the release lever 69 moves to release the firing pin 41. The firing pin slides in bearings in the top and bottom plates 26 and 18 respectively, and is provided, intermediate its ends, with an integral collar 42, which forms not only an abutment for the firing spring 43, but a sear for the trigger 44 on the rotatable shaft carrying the release lever 69. By referring to Fig. 10 it will be noted that the trigger 44 is bevelled or rounded in order to facilitate rotation of the shaft 45 by the firing pin 43- when the notch 67 registers with the extension 68 of the release lever. Slidably mounted in the plates 25 and 26 is a pin 31, provided with a collar intermediate its ends, and the upper end of this pin 31 lies normally in the path of movement of the end of the release lever 69, adjacent the extension 68 thereof, and prevents the extension '68 from. engaging with the periphery of the setting plate 62. The shock of firing causes the pin 31 to move downward, as viewed in Fig. 9, moving the upper end out of engagement with the release lever 69, and allowing the extension 68 to engage the setting plate 62.

The clock or timing movement 19 -is placed in position in the recess 17, so that the firing pin 41 is in alinement with the depression 15, in which is located the primer 16 and is held in such position by the screws 20.

The upper outer portion of the fuse block is cut away at to provide a bearinu surface for the setting cap or head 51. 6n the vertical face of the cut away portion 50 is an annular groove 52, in which is placed a ring 53 of spring metal. The outside diameter of this ring 53 when expanded, is

. greater than the internal diameter of the lower portion of the setting cap or head 51,

'said cap or. head to be forced over the ring 53 and into the position shown in Fig. 2.

A plurality of screws 54 pass through the setting cap or head 51 and engage with the ring 53 to alter the tension thereof. The power required to turn the cap or head51 during the setting operation may be thus varied to suit the convenienceof the operator.

On the interior wall of the cap or head 51 is attached, in longitudinal groove 76, by the screws and nuts 55Iand 56 respectively, a fiat spring 57, provided with a notch 58, struck up from the metal of the spring. The lower end of the spring 57 is provided with a tooth 59 which engages with and completely spans a notch 60 in the setting plate 62 and also engages with the spring plate 61 secured to the setting plate 62, which in turn is positively secured to the staff 30. The sprlng 57 is so tensioned as to tend to move intoengagement with the interior wall of the cap or head 51, and thus disengage the tooth 59 from the notch 60, and is normally prevented from doing so by the movable weight 63 which. is positioned on the spring and above the notch 58. This weight 63 is forced by the spring 57 into the depression 77 in the interior wall of the cap 51. Under the above conditions, the setting cap or head 51, when turned, will rotate the setting plate 62, which may thus be moved into any desired position, the amount of such movement being noted by the graduations 64 on the lower'periphery of the setting cap or head 51 in connection with the zero mark on the periphe of the fuse block.

In or er that the position of the settin plate 62 may be positively determined, have provided a peek hole' 65 in the side wall of the setting cap or head 51, which peek hole is in alinement with the tooth 59 on the spring 57. A flat screw 66 normally closes' the peek hole 65, and when in position, the outer surface of said screw is flush with the outer surface of the cap or head 51.

The operation is as follows, it being assumed that the fuse block and associated parts are attached to a shell, that the opcap or head is functioning properly, he removes the fiat screw 66 from the peek hole 65 and, by observing the condition of the mechanism, reassures himself regarding this point. The rotation of the setting cap or head 51 causes a corresponding rotation of the setting plate 62, due to the fact that such plate and cap are positively coupled or geared together by the tooth 59 of the spring 57 engaging in the notch 60 of the plate 61. Such rotation of the setting plate 62 moves the notch 67 therein relatively to the upward extension 68 of the release lever 69, and altering the time necessary for said notch 67 to come into operative position with -)respect to said extension. 68. If now, the

hell is fired from the gun, the shock of firing does several things 5 it causes the pin 31 to move towards the middle plate 25 and allows the outer end thereof to disengage itself from the end of the release lever 69 the extension 68 of said release lever 69 engages with the periphery of the setting plate 62; the free weighted end of the stop 32 moves-downwardly and frees itself from the end of the stop lever 33 of the timing mechanism-this stop being of dead as distinguished from spring metal, remains in its downward position-this operation allows the timing train to start; the pin 85moves downward in the hole 81 out of the path of rotation'of the plate 22 and wedges itself on the taper 81; the weight 63 is forced downward, as viewed in Fig. .2, past the notch 58 and the spring 57, moving outwardly toward the interior wall of the cap or head 51, causes the disengagement of the tooth 59' from the notch 60the setting cap is now free to rotate; the hub 34 is forced downwardly, as viewed in Fig. 5, and is rigidly clutched to the staff 30, the tapering form of the staff and passage in the hub 34 assisting in such clutching operation the setting cap 62 being fast to the staff 30, is now rotated by the timing train.

All of the above operations occur instan-' taneously and simultaneously, the result being that the timing train and the setting plate 62 begin their rotation at the same instant and the time "of the release of the firing pin is measured from that instant. As the shell leaves the chamber of the gun, it takes the rifling, rand v in consequence is rapidly rotated. When the centrifugal force generated by such rotation is equal to or exceeds a certain predetermined amount, the pivoted plate or shutter 22 overcomes the tension of the spring 23 and moves to a position to expose the primer. After the timing train has rotated the setting plate 62 sufiiciently to cause the notch 67 therein to register with the extension 68 of the release lever 69, the tension of the firing spring 43 is suflicient to cause, by means of the collar 42 and bevelled trigger 44,- the rotation of the shaft 45, and' the release of the firing pin 41.

From the above, it is obvious that until the shell is set in rotation by the rifling of and 29 the cover plate in which plate is rotatably mounted the center .stafi 30. Secured to the hub 34 is the radially extending arm 33, which, as described in connection with Figs. 5 and 8, is normally in engagement with and is prevented from moving by, the weighted arm 32. As a substitute for the Wei hted arm 32, I may provide a rod or shaft 0 mounted parallel to the staff 30 in the top and bottom plates 26 and 25 respectively. This rod or shaft 70 is provided near its lower end, with a tapered. portion 71 and slidably mounted on the rod or shaft 70 is a sleeve 72, the lower portion of the bore of which is tapered to correspond with'the taper 71 on the rod or shaft 70. The upper portion of the sleeve 72 is'groovedat 73 which engages with the outer end of the arm" 33. The sleeve 72engaging with the arm 33, prevents said arm, and therefore the timing train, from rotatin while the arm 33 engaging .in the groove 73, prevents, under normal conditions, the separation of the sleeve and arm. When the shell is fired from the gun, the shock of firing forces said sleeve downward along the rod or shaft 70 into the position shown in Fig. 12, and releasing it from the arm 33. The timing train thereupon starts, and, what is of great importance, the sleeve 72 wedges itself onto the tapered portion 71 of the rod or shaft,

and preventing the rebound of the sleeve with the consequent liability of stopping the timing train.

As my invention relates to a type of device that is intricate in character, I have necessarily described the preferred embodiment thereof somewhat in detail. It is to be understood however, that I may vary the construction and arrangement of the elements constituting my invention within considerably wide limits without departing from the spirit thereof.

My invention is further described and dcfined in the form of claims as follows:

1. In a time fuse, the combination of a base,'a timing train mounted thereon, a firing pin, controlled by said timing train, asafety device operable only by centrifugal force, said device being located in the base and in the path of movement of the firing pin, and a lock for said plate normallyin the path of movement of the plate, and movable out o-f said path by the shock of firing.

2. In a time fuse, the combination of a base, a timing train mounted thereon, a firing pin, operated by said timing train, a primer located in the base and in the path of movement of the firing pin, a ivotally mounted plate in said base, norma interposed between the primer and the fir1ng pin, and movable out of said position bycentrifugal force, and a lock for said plate operable to release the plate by the shock of 3. A safety device for fuses, comprising a base, a movable plate, engaging the plate and holding it in operative position, a tapered pin, a circumferential groove therein near one end of said pin, a spring ring in said groove engagin the base and normally holding the pin in t e path of movement of the plate, and means cooperating with the tapered pin after the movement thereof to maintain the pin out of the path of movement of the plate. I

4. In a mechanical time fuse for detonating the explosive charge of a shell, including a timing train, a central staff therefor tapered intermediate its ends, a hub, mounted on said staff and having a taper corresponding to the taper thereon, said hub being normally rotatable on said stafi, a gear wheel fixed on the hub and connected to the timing train, and a setting plate fixed to thestafi' and by means of which the timing 0 eration of the train may be varied, said hu being forced onto the taper of the staff by the shock of firing to couple the setting plate to the timing train.

5. Safety setting means for time fuses comprising a timing train, a rotatable plate connected therewith, a firing notch in said plate, settin means including a depending spring comp etely spanning said notch, and means for operating the spring to rotate the setting plate to vary the setting of the timing train.

6. A mechanical time fuse for detonating the explosive charge ofa shell, includinga timing train, a setting plate therefor, a setting cap for rotating said late relatively to the timing train to vary t e time of detonation of the charge, a spring lever rigidly attached at one end to the interior of the setting cap, cooperating means on the free end of the spring lever and on the periphery of the setting plate, for coupling said plate and cap together during the setting operation, and a sliding weight on the s ringlever, slidable toward the free end t ereof on the shock of firing, to allow the free end of the spring lever to move outwardlg to free the cap from the plate.

7. mechanical time fuse for detonating the explosive charge of a shell having, in combination, a timing train, a rotatable element therein, an arm, rigidly attached to the rotatable element and rotatable therewith, and an arm attached at one end to a stationary part of the timing train, a weight attached to the free end of said arm, the free end of said arm lying normally in the path of movement of the rotatable element, the free end of said arm being displaced by the shock of firing to free the rotatable element and allow the starting of the timing train.

8. A mechanical time fuse for detonating the explosive charge of a shell having, in combination, a timmg train, a rotatable element therein, an arm, rigidly attached to the rotatable element and rotatable therewith, and an arm of non-spring metal attached at one end to a stationary part of the timing train, a weight attached to the free end of the said arm, the free end of said arm lying normally i@ the path of movement of the rotatable element and being displaced by the shock of firing to free the rotatable element and allow the starting of the timing train.

9. A mechanical time fuse for detonating'the explosive charge of a shell having in combination, a timing train, a rotatable element therein, an arm rigidly attached to the rotatable element and rotatable therewith, and an arm of non-spring metal attached at one end to a stationary part of the timing train, a weight attached to the free end of the said arm, the free end of said arm lying normall in the path of movement of the rotatab e element and being permanently displaced'by the shock of firing to free the rotatable element and allow the starting of the timing train.

10. A mechanical time fuse for detonating the explosive charge of a shell having, in combination, a timing train, a firing pin, release means for said firing pin associated with the timing train and operable thereby to release the firing pin after a predetermined length of time, means associated with said timing train to vary the time of operation of the firin pin at will, a safety device operable on t e shock of firing to start the'timing train in motion, and a second safety device, operable by centrifugal force to clear a path for the firing pin after its release.

11. A safety device for fuses, comprising a base, a plate movable adjacent thereto, a tapered recess in said base, a pin tapered to correspond with the tapered recess, a circumferential groove in said pin near one end thereof, a sprmg ring in said groove en aging the face of the base and normally ho ding the pin in the path of movement of the plate, the inertia of said pin operating, on the shock of firing, to move the pin out of the path of movement of the plate and into engagement with the tapered recess in the base.

' 12. A safety device for fuses, comprising a base, a plate pivotally mounted thereon, a recess in said base and tapered at the bottom, a pin tapered to correspond with the tapered portion of the recess, a circumferential groove in said pin near the end remote from the tapered portion, a spring ring in said groove engaging the face of the base and normally holding, the grooved end of the pin in the path of movement of the pivotal plate, and the tapered portion out of engagement \viththe tapered portion ofthe recess, the inertia of said pin operating, on the shock of firing, to move the pin out of the path of movement of the plate and into engagement with the tapered portion of the recess in the base.

13. Asafety device for fuses, comprising a base, a plate pivotally mounted thereon,

a recess in said base, a pin slidably mounted in said recess, means for holding one end of said pin out of said recess and in the path of movement of the pivoted plate, said pin operable on the shock of firing to be released from the holding means and to move into said recess out of the path of movement of said pivoted plate, and means on the pin and at the bottom of the recess for holding the pin in its operated position.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

FREDRIOK WV. BOLD.

W'itnesses:

\VILLIaM H. NEAGLE, JAMEs R. HODDER.

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