US2720835A - Temperature compensated shock resistant fuse - Google Patents

Description

oct. 18, 1955 H. W HOUSTON ETAL TEMPERATURE COMENSATED SHOCK RESISTANT FUSE Filed June 5, 1948 III/[IIIA VIII/'lill' l L 5 Sheets-Sheet I Fig. L21- Oct. 18, 1955 H. w. HOUSTON ETAL 2,720,835

TEMPERATURE COMPENSTED SHOCK RESISTANT FUSE Filed June 3, 1948 Eig. a- 5 5 Sheets-Sheet 2 Fi 4 M Ef 94 i FEU mf l s @V295 Syvum/Mom H W. Hmunn T T- E.- Urban 354g IL K Allj. DTL l 3 #mf 0, @im

Oct. 18, 1955 H. w. HOUSTON ET A1. 2,720,835

TEMPERATURE COMPENSATED SHOCK RESISTANT FUSE United States Patent -nl TEMPERATURE CMPENSATEE) SHOCK RESISTANT FUSE Application .lune 3, 1948, Serial No. 30,864 8 Claims. (Cl. IGZ-70) Urbany, Los Angeles,

This invention relates to an atmospheric pressure responsive fuse, and is designed to provide a fuse for detonating an explosive charge, particularly an aerial bomb. The fuse functions automatically when the charge attains a determined altitude. The invention provides alternative operating mechanisms for operation on ascent and descent of the charge. It also provides shock-resistant means t prevent accidental functioning of the fuse due to vibration or impact. There is also provided compensation means to counteract atmospheric pressurevariations due to temperature variations. tures of the fuse are the sectional case for enclosing and supporting the operative mechanism, the restraining means for releasably latching the iring means, the pressure operated means for releasing the restraining means, the

shock-resistant means to prevent accidental release of the restraining means, and the compensation means responsive to temperature variations.

While there have been illustratedin the drawings tiled herewith and hereinafter fully described several specific embodiments of the invention, it is to be distinctly understood that the invention is not considered to be limited to said specific embodiments and that its scope is defined by the claims appended hereto.

In the drawings:

Fig. 1 is a side elevation of the fuse and charge, partly in section;

Fig. 2 is a vertical section in the direction of the arrows;

Fig. 3 is a vertical section in the direction of the arrows;

Figures 4 through 8 are sectional views in planes perpendicular to the longitudinal axis of the instrument as indicated by the lines 4 4; 5 5; 6 6; 7 7 and 8 8, respectively, of Figure 2.

Fig. 9 is a fragmentary vertical section, similar to the upper portion of Fig. 3, showing the thermostatic adjusting elements modified by elevation of temperature;

Fig. l0 is a vertical section similar to Fig. 3 showing a modified form of the fuse;

Fig. ll is a fragmentary vertical section of another modified form of the fuse; Fig. 12 is a detail view of one of the dogs of the latching means;

Fig. 13 is a detail view of the tiring pin.

As illustrated in the drawings, the fuse has a tubular case for enclosing and supporting the operating mechanism, and comprising live, cylindrical, co-axial elements inter-engaged in lapped joints for facilitating assembly and cemented together by suitable means when assembled. A cap 1 for closing the top of the case is seated on an element 2 and has a neck 3 projecting downwardly into the upper end of element 2 and suitably axially spaced relative to an interior peripheral flange 4 of element 2 to secure the rim of a flexible element 63 therebetween. Element 2 is seated on an element 5 which has a neck 6 projecting upwardly into the lower end of element 2. Element on the line 2 2 of Fig. 1,

on the line 3 3 of Fig. 2,

The particularly novel fea- 2,720,835 Patented Oct. 18, 1955 5 is seated on an element 7 which has a neck 8 projecting upwardly into the lower end of element 5 and suitably axially spaced relative to an interior peripheral shoulder 9 on element 5 to clamp the rim of a flexible diaphragm 14. Element 7 is seated on an element 10 and has a neck 11 which projects downwardly into the upper end of element 10. Element 10 has a longitudinal key lll-a received in key-way 11-a in neck 11 to prevent relative rotation of elements 7 and 10. The lower end of neck 11 is spaced from a peripheral shoulder 12 on element 10 to clamp a circular disc 24. Element 10 has an exterior peripheral groove 13 to receive the adjacent end of a container 44.

Between the neck 8 of the element 7 and the shoulder 9 of the element 5, there is mounted a circular, concaveconvex flexible diaphragm 14, of any suitable material, such as rubber, having a peripheral flange 15 congured to be engaged by the co-acting faces of neck 8 and shoulder 9 when the element 5 is seated on the element 7. The diaphragm 14 is so mounted in the case as to effect a gas-tight joint therewith. The diaphragm 14 has a central, thickened and bored portion 16 on which is mounted a plate 17 supporting a clevis 18, and having a threaded bolt 19 passed through the diaphragm 14 and a plate 20, and provided with a nut 21 for clamping the diaphragm 14 between plates 17 and 20 in a gas-tight joint therewith. The plate has formed integral therewith a depending cage 22 having on its lower end a latch 23 in the form of a ring coaxial with diaphragm 14.

Between the neck 11 of the element 7 and the shoulder 12 of the element 10, there is mounted a circular disc 24 clamped securely in position when the element 7 is seated on the element 10. Disc 24 has a central bore 25 and a pair of upstanding lugs 26 at the sides of bore 25, respectively, in which are pivoted a pair of dogs 27 in the upper ends of which are journaled rollers 2S. Slidably received in the bore there is a firing pin 29 having a peripheral bevel 30 on its upper end and a peripheral groove 31 adjacent thereto having upper and lower bevelled cam faces 32 and 33. Dogs 27 have bevelled noses 34 intruded into groove 31 and engaging face 32 of firing pin 29 when the dogs 27 are relatively proximately disposed by the rollers 28 latched by the circumscribing ring 23, as shown in Fig. 3. The pin 29 has a second peripheral groove 35 inferior to groove 31. Formed integrally with the disc 24, there is a tubular housing 36, coaxial with disc 24, and into which depends the firing pin 29 which has on its lower end a peripheral flange 37. A coil spring 38 about pin 29 is confined between disc 24 and flange 37, biasing pin 29 downwardly. Pin 29 has, on its lower extremity, a detonating point 39. Threaded on the lower end of housing 36 is a casing 40 in which is mounted a primer 41 for a booster charge 42 in casing 40. Booster charge 42 is disposed in a main explosive charge 43 for the ring of which the novel fuse is designed, and which is packaged in a container 44, the open neck 45 of which is seated in groove 13 of element 10 of the case of the fuse, lashing 46 serving to unite the case and container 44.

Carried on the upper end of the neck 6 of the element 5 of the case there is a spider 47 (see Figure 5) having convex ends 48 seated against the element 2, and depending lugs 49 in which are pivoted a pair of bell cranks 50 having forked ends 51, embracing pin 52 in clevis 18, and arms S3 carrying inertia masses 54. Mounted on the spider 47 by bolts 55, there is a V-shaped, bimetallic, thermostatic member 56 comprising two arms 57 and 58 extending upwardly in element 2 of the case. Arm 58 is provided on its upper end with a bracket 59 supporting a second V-shaped, bimetallic, thermostatic member 6l) comprising two arms 61 and 62, arm 61 being attached to bracket 59. As shown in Fig. 3, the members 56 and 60 are so dimensioned and related,

3 that member 56 comprehends member 60, the arms 57, 58, 61 and 62 being normally parallel.

Between the neck 3 of the cap 1 of the case and the flange 4 of the element 2, there is mounted a circulai exible diaphragm 63 of material such as rubber 'having a peripheral liange 64 configured to beengaged by the co-acting faces of neck 3 and ange 4 when the cap -1 is seated Von the 'element 2. The diaphragm 63 is lso mounted in the case as to effect a gas-tight joint therewith.

The diaphragm 63 is formed as a frusto-conical member having 'a central, thickened and bored portion 65 to which is fastened a plate 66 having a threaded bolt 67 passed through portion 65 and a Washer 68 thereon and provided with 'a nut 69 for clamping the diaphragm 63 between plate 66 and washer 68 in a gas-tight joint therewith. The plate 66 is provided with depending lugs 70 (see Figure '3) in which is pivoted one arm of a bell crank 71, the 'other 'arm of which is pivoted to a link 72 pivotally mounted on a bail 73 mounted in arm 57 of the thermostatic member 56. Bell crank 71-is pivoted intermediate its arms to one arm of a Second bell crank 74 which is received in the slotted upper end ofA armV 57 and pivoted on a bail 75 mounted in arm 57. The other arm of bell crank 74 is pivoted to a link 76 pivoted on a bracket 77 mounted on the upper end of arm 62 of the thermostatic member l 60.

, As shown in Figs. 3 vand 9, when the 'parts 'are -assembled as described, the diaphragm 63 is dshed, its degree of deforma-tion depending upon the position of plate 66 determined by the positions ofthe thermostatic arms 57 and 62 and their associated linkage.

A Cap 1 has an orifice 78 to provide communication fork the interior of cap 1 with atmosphere.

The element 2 Yhas an` orifice79 (Figures 2 -and 4) to providecommunication for the interior of the casing between the diaphragms 14 and 63. Snugly fitted in 'the orifice 79, therevis a nipple 80` of -a plug 81 having a threaded bore '82 in which is threaded arbolt 83 with slotted head S4 seatedAin recess 85 of plug 81. The nipple 80, Ethe recess 35 'and the bore 82 are co-axial. Bolt 83 has a central bore 86 Twith which connects a radial bore S7 opening throughthe periphery of bolt 83 to its en'd adjacentghead 54. The lparts are so designed and Vrelatedthat when the bolt 83 is set up kin plug 81 s o that head S4 is seated in recess 85, the bore 87 is closed toA seal that portionofthe 4interior of the casing between diaphragrns '14 and 63, and the -head'8'4 is disposed interiorly of the periphery of element 2, and that when bolt 83, uhscrewevd by turning head A84 'with a lsuitable tool, Yis retracted sufficiently to withdraw bore 87 from bore 'S2 vand into recess 85, vand head v84 is exterior of the periphery of element 2, the bores 86 and 87 afford lcommunication for the interior of the casing to atmosphere.

The ,elernent and neck A1-1 of the element 7 have co-axial transverse orifices 8S and 89Figure4 '8, -in which ils slidably jdisposed `a rsafety pin 90 which is Vpassed through orice`su91so disposed in Llugs 26 on discl24 lals to pass pin 90 Athrough `groove 35 in firing lpin 29,. j he safety pin 90 has an arm 92 normal to pin 90 and exterior of theperiphery of the'case (Figs. l, 3 kand 8). l A T he element 7 has a pair of relatively spaced Vtransverse parallelly disposed orifices 93 and sockets 94 co-axial lwithrorificesl 93, respectively. A hairpin detent 95 has itsvlegs 96 slidable through orifices 93, Vand their ends :seated in sockets 94. Orifices 93 -and socketsl94 are so disposed Vas to position the legs 496 about the dogs 27 when the dogs 27 are disposed in 'ring 23. The bight of detent 95, connecting the legs 96, has swingable lthereon a tongue or strap v98 received against the periphery of the case when the detent -95 is mounted in the case, and confined by aring 99 slidable on the case. It will vbe noted (Fig. l) that the arm 92 of safety-pin 90 Yis `confined by the `detent 95, so that detent 95 must be removed to permit removal of pin 90, and (Fig. 2) that ring 99 is disposed over orifice 79 when psitihed to confine tongue 98.

In Fig. l0, there is shown a modified form of the fuse in which the thermostatic members, exible diaphragm and linkage therefor are eliminated. In this form of the device, the element `2 has an inner peripheral ange 4-a spaced from the lower end of neck 3 of cap 1. Between neck 3 and ange 4-a, there is mounted appartition 100 in a gas-tight Vjoint therewith and forming the upper end of the chamber in the casing extending from ythe diaphragm 14 to partition 100. Partition 100 has a central boss 101 projecting upwardly and a socket 1'02 on its lower lside in which is seated, in a gas-tight joint, a capillary tube 103 having adminute bore 104. The boss 101 has a minute bore 105 connecting socket 102 with the interior of cap 1. Except for the above-described elements the form of the device shownin Fig. 10 is identical with the form shown Yin Figs. l to 9..

In Fig. ll, there is s hown a modifiedl formof the device in which a Iliexible diaphragm 14-z is designed vto flex upwardly to raise the latch 23. In this Vform, a shoulder V9-.a ofA an element l5-a is seated on neck 8 of. the element 7 and the peripheral flange 15u-a of v'the diaphragmM-a is seated on a shoulder 9-71 of the element S. A sleeve 6a, fitted in the upper end 'oflellemen't 5-a land projecting therefrom, is seated on flange 15-a. Element 2-a is fitted "bout the projectlng portion of sleeve A6--a and is seated on Athe element S-a. The sleeve l6-a comprises tw'o Asemicylindrical portions for a purpose presently explained. `The spider 47 is mounted on `the ltop of sleeve 46-al and has lugs 2l9-a somewhat longer than 'lugs 49 of the vfo'rin shown in Figs. 1 to 9. "On lugs t9-1, there are pivdted two bell cranks 'S0-a, which are rever'selyl disposed relative to elevis 18 "from Athe disposition of bell eranks 50,"t`9 prevent accidental raising ofthe ring 23. O'ther'parts of this, form ofthe Vfuse areidentieal'with corresponding parts of the form shown'in Figs. ll to 9. Y

The method o'f assembling |the abovede`s`erib`ed k'parts iwill "n'ow be explained. The thermostatic member '56wit'h Lr`n`eni`t5`er A60 and the 'linkager'noited thereon lis 'mounted on the spider 47. The bell c'rilks `50 'reinonted on `lugs 49 lof the spider 47, 4and pin 52 passed 'through c'le'vs 1S lai'id forked ends '51 'of cranks 50, attaching clev'is `18, plate 17 andbolt 19, under spider 47 rSpider 47 'is `then seated o`n eck`6 VAof element 5. The diaphragm is'then mounted on bolt 19 and cage 23 Vis mounted on bolt v"I9, 'me "prrs being pfpn'y reiste@ by 'sifihgp ntzi on bolt *19,A and -the flange 15 of vdiaphragm 14 'being s'e'ted on shoulder i9 lof "element 5. Element 2, :withpliig 81 4irio'il'ritie'i therein, isthen seated fonielemeit 5, the ehfds '48 of spider`47 as well afsiiieck 6`of element'S'and thelw'e end of element 2 being 1properly leiiiitedto form 'a g'as- `ti`ght joint. `The -flexible 'diaphragm 1'63 `is 'mounted V'on plate J66 'dfth'e liiikagefon ythrnis'tfati'c `r`ne1i1berf56 ``rid its iian'g'e'l seated on 'ia`ge4jf 'el'eileit *2. Cap 1`is appliedto upper endif'eleriie'nt 2, ifs'iek 3 engagifgthe iiange 64, and the parts cemented 'to fin "a ygastifgh't 'joint l The dogs 27 are mounted on fof'dis'c 2/4 'which is then seted'n nek Jll'oifeleinei1`t 7 4Ail'dlceilrte'd thereto. Detent is then inserted `into element 7 "embracing -dogs 27.` Pin 2 9 with spriiig 38thereonis'iiisetedthrbgh "hoiis'irig bore 25,

braced by detent 95 and pin 29 is held by pin 90, the noses 34 engage the upper edge of cam face 32 and rollers 28 are suciently proximate for ring 23 to embrace them slightly above their axes. It is obvious that as dogs 27 are moved into adjusted position by seating element 7, the rollers 28 rotate as their axes become aligned with the transverse axis of ring 23, and that dogs 27 are moved away from legs 96 of detent 95 and toward pin 29 which causes noses 34 to cam upwardly pin 29 suiciently to free pin 90 which is then removed. Element is then applied to element 7, key 10-a seating in key-way 11-a and shoulder 12 bearing on the disc 24.

Detent 95 is removed, pin 90 is inserted and detent 95 replaced, engaging arm 92 of pin 90 (Fig. 1). Bolt 83 is threaded in bore 82 of plug 81 suiciently for its head 84 to be received in recess 85.

Ring 99 is placed about element 2 to confine tongue 98 of detent 95. Casing 40 with detonator 41 and booster charge 42 may be threaded on outer end of housing 36 immediately prior to applying the fuse to the explosive charge.

In assembling the form of the fuse shown in Fig. 10, after element 2 has been seated on the element 5, the partition 100 is seated on the flange 4-a of element 2. The tube 103, which had been mounted in socket 102 in boss 101 of partition 100 before partition 100 is seated on flange 4a, is disposed within element 2. When thus assembled the parts are cemented to form a gas-tight joint. Cap 1 is then applied to upper end of element 2, the neck 3 of cap 1 bearing on the partition 100, and the parts are cemented.

The method of assembling the form of the fuse shown in Fig. l1 will now be explained.

When the dogs 27 have been assembled with pin 29 on disc 24 and in element 7, as above described, element S-a is mounted on the element 7. Latch ring 23, diaphragm 14-a and clevis 18 are then assembled by setting up nut 21 on bolt 19. Ring 23 is then moved downwardly by pressure on clevis 18 and bolt 19 until dogs 27 are disposed as shown in Fig. l1, and flange -a of diaphragm 14-a is seated on shoulder 94b of element S-a. One of the semicylindrical portions of the sleeve 6-a is then mounted in the element 5-a and on flange 15-a, to support the spider 47 which is then mounted thereon so that clevis 18 is disposed between lugs 49-a. Bell cranks 50-a are then applied to clevis 18 and pivoted in lugs 49-a. It is to be understood that the portion of sleeve 6-a, previously mounted, is so disposed as to afford access between diaphragm 14-a and spider 47 to permit mounting bell cranks Slt-a. The other portion of sleeve 6-a is then mounted in element S-a and on flange 15-a, and element 2-a is disposed about the upper end of sleeve 6-a and seated on element S-a the parts being cemented to form a gas-tight joint. It is to be understood that before the spider 47 is mounted on sleeve 6-a, the thermostatic element 56 and its associated parts are mounted on the spider 47. The remainder of the assembling is as previously described. i

From the foregoing description of the details of construction of the fuse, its use and operation can be understood. The operation of the form of the fuse shown in Figs. 1 to 9 will now be described. This form of the fuse is designed to function on reduction of atmosphereic pressure viz. on ascent. With parts assembled as shown in Figs. 1 to 8, the fuse is conditioned for use. Before 'the fuse is connected with container 44, ring 99 is moved upwardly on the case, off of orifice 79 and tongue 98, and hair-pin detent 95 is withdrawn, releasing safety pin 90. It will be noted (Fig. 3) that when the dogs 27 are embraced by latch 23, both legs 96 and pin 90 are free for unobstructed withdrawal. However, should the operative parts have become accidentally displaced so that dogs 27 are not held in latched position by ring 23, the dogs 27 will bear against legs 96 to impede their withdrawal and that when legs 96 are withdrawn, the dogs 27 cammed out of groove 31 by upper cam face 32 will release firing pin 29 which is projected by its spring 38 to engage safety pin in groove 35, thereby impeding removal of pin 90. Should it be found that pin 90 is not freely withdrawable, the fuse is shown to be in unusable condition and cannot be used, until tiring pin 29 is re-cocked. When theparts are properly disposed, pin 90 can be readily withdrawn. After the detent has been removed, safety pin 90 is allowed to remain in place as a precaution to prevent accidental release of tiring pin 29. The bolt 83 is then screwed out suiiciently to put the chamber between diaphragms 14 and 63 in communication with atmosphere through bores 86 and 87, the chamber being otherwise sealed. It will be noted that withdrawal of hairpin detent 95 opens oritices 93 through which the chamber between diaphragm 14 and disc 24 is put in communication with atmosphere. Thus it is obvious that diaphragm 14 is subjected to uniform atmospheric pressure on both sides and is thereby immobilized. When the device is at that altitude at which the desired atmospheric pressure obtains for charging the chamber between diaphragms 14 and 63, the bolt 83 is set up in plug 81 to close bore 87, thus completely sealing the chamber between diaphragms 14 and 63. The fuse is then attached to the charged container 44 and safety pin 90 is withdrawn. The fuse is now armed and ready to function. When the device is elevated, above. the altitude at which it is armed, to that altitude at which the atmosphere pressure is sufficiently reduced below that of the pressure in the upper chamber, the diaphragm 14 is deformed, since the chamber below diaphragm 14 is charged through orifices 88, 89 and 93 with the atmosphere of reduced pressure. It is to be understood that the parts are constructed and related so that at that point in ascent of the device at which the pressure differential reaches the desired amount, the diaphragm 14 will be flexed downwardly out of its normally upwardly curved position to depress ring 23 sufficiently to pass below the axes of the rollers 28 which are pressed outwardly by action of spring 38 and cam surface 32 on noses 34 of dogs 27, tending to force ring 23 downwardly suciently to release dogs 27 from pin 29 which is projected downwardly by spring 38 through tube 36, its point 39 striking detonator 41 firing booster charge 42 and exploding charge 43.

It will be noted (Figs. 2 and 3) that as the diaphragm 14 is normally curved upwardly and cannot be moved further upwardly and the ring 23 is so related to diaphragm 14 as to latch dogs 27 when diaphragm 14 is normally curved upwardly, the ring 23 cannot be moved upwardly to release the dogs 27. There is, therefore, no need for means to prevent accidental lifting of ring 23. However, since the fuse functions by flexing of the diaphragm 14 downwardly to depress the ring 23 to release the dogs 27, the device is provided with means to prevent accidental exng of the diaphragm 14 downwardly, as by vibration to which the device may be subjected. The inertia masses 54 are so connected to the flexible structure by the crank arms 53 as to counteract any tendency of the diaphragm 14 and ring 23 to move downwardly, since any impulse by vibration tending to move the diaphragm 14 and ring 23 downwardly tends to move masses 54 downwardly which, through crank arms 53, tend to move diaphragm 14 and ring 23 upwardly.

In the foregoing description of the fuse it was explained that the fuse functions when the differential of the pressures on the opposite sides of diaphragm'14 reaches the desired amount. Itis obvious, therefore, that for the desired proper functioning of the fuse the pressure in the sealed chamber must be maintained uniform. Since the mass of atmosphere in the sealed chamber is subject to pressure variations incident to temperature variations, the device is provided with thermostatic automatic means for varying the volumetric capacity of the sealed chamber to maintain uniformity of pressure of the mass of atmosphere sealed therein. In the form of the device shown in Figs.

1 t9, this means comprises the thermostatic members 56 and 60, the iiexible diaphragm 63 and the linkage therefor. As clearly shown in lFig. 9, when the 'temperature in the sealed chamber is elevated to a degree to increase the pressure of the atmosphere in the chamber due to its expansion by heating, the Varms 57 and 58 of the thermostatic Trnember S6 are cause to move apart, and the arms 6l 'and 62 of 'the member 60 move likewise. Since member 60 is movable bodily with arm 58, the movement of arm 62 is augmented. The deflection of arm 57 moves bell-crank 74 bodily relative to the axis of bolt 67 in the center of diaphragm 63, and'consequently moves bell-crank 7-1 likewise, tending to lift diaphragm 63. Simultaneo'usiy this movement 'of arm 57 cau'se's link 7-2 to rock crankarm 7L tending to lift diaphragm 63. Simultaneously, the movement of arm 62 causes link 76 to rock bellcrank 7'4 raising bell-crank 71 bodily, tending to lift diaphragm 63. -It is obvious that this raising of diaphragm 63, increasing the volumetric capacity of the chamber, compensates the expansion to maintain the desired pressure in the chamber. It is obvious lthat the reverse movements are produced by reduction of temperature Ycausing reduction of pressure due Vto 'contraction by cooling.

As above pointed out, in the form of the device shown in Fig'. l0, the thermostatic compensating means is eliminated. This form of the device is provided with the capillary tube 103 to provide means to maintain constant pressure of `'the atmosphere in the sealed chamber. Increased temperature in the sealed chamber, causing expansion of the atmosphere produces evacuation of that portion of the atmosphere, through tube 103, to compensate the expansion to maintain uniform pressure on diaphragm 14. Reverse operation, on cooling, effects the desired result'. 'It is obvious that the cross-sectional area 'of bore 104 and length of tube 103 are designed to efiect `the above described results. Since the compensations by this means are effected at 'determined speeds, 'it is to be understood that the functioning of ythis form of the fuse is directly affected by the rate-of-climb whereby the pressu-re differential is effected. Should the speed of ascent of `the device be considerably accelerated, the degree of compensation'is consequently reduced, and compensation is increased at reduced rate of speed.

A-As :above pointed out, in the 'form of the fuse shown in Fig. l1, the fiexible diaphragm 'Ilka is designed to fiex upwardly and-it is lobvious 'that i'n this form of the device -the diaphragm 14-a is flexed by the pressure exerted by the atmosphere in the chamber below ldiaphragm l14-a when it becomes superior to the pressure in the lsealed chamber above the diaphragm 14-a, the device functioning on descent. It is to be understood that lthe compensati-ng means shown-in Figs. 3 and 10 can be used alternatively with either Yof the forms of the -fus'e -shown in -Figs 3 and 1-1.

We claim:

1 In :a lfuse -for `detonating -an explosive charge, the combinationof a tubular case, a transverse closure 4sealing yone end of said-case; a fiexible transverse sealing wall intermediate the ends of Vsaid case dividing said case into first and second Vco-axial chambers, said case having an orifice therein providing a single rport for the first of said chambers between said closure and said wall, and a plu'- "rality of orifices therein providing aplurality of ports'for the ysecond of said chambers; a Vremovable closure for sealing said orifice providing said single port; a'transverse closure for the other end of said case, and spaced-from said wall-to define said second chamber; firing pin means vfor detonating'the charge, said firing pin means being supported Aon--said seco'nd closure, means biasing -said firing pin means to firinglposition; a dogmounted in Ysaid second chamberandpivotable from 'a firstposition engaging and holding said 'firingpin means against movement to 'firing fposition, and ya `second fposition releasing said firing :pin means, and a latch ringconnected with said'sealing wall,

said latch ring normally engaging said dog to hold the same in first position and movable with said sealing wall in response to a change in ldifierential pressure within and without -said first chamber, to release said dog. I I

2f. lIn a pressure-differential-responsive fuse, a tubular casing, walls closing the respective ends of said casing, a fiexible diaphragm across said casing between said walls and dividing said casing into first and second chambers, a firing pin reciprocably mounted inthe end wall of one said chamber, spring means urging said pin into firing movement, a dog operable in a first position to hold said pin retracted against the action of `said spring means, means connected withvsaid diaphragm and engageable with said dog -in an undefiect'ed position of said diaphragm to hold said 4dog in -first position and movable with said diaphragm in response to a predetermined pressure differential between said chambers to release said dog, valve means operable to selectively connect one said chamber with the atmosphere, and means including a temperature-responsive element in said last-named chamber to vary the volume thereof directly with temperature to 'thereby maintain constant the pressure in said last-named chamber.

3. Ina pressure-differential-responsive fuse, a tubular casing, first and second walls closing the respective `ends of said casing, a fiexible gas-tight diaphragm in said casing and, with said walls, dividing said casing into first and second chambers, a firing .pin axially mounted in said second wall for movement from a retracted position to firing position, a spring urging said firing pin into firing position, a plurality of dogs mounted on said second wall about said firing pin, for pivotal movement in respective radial planes from a first posit-ion engaging and holding said firing pin in retracted position to a second position releasing said pin, a ring secured to said diaphragm and normally surrounding and Aholding said dogs in first position and movedby and with ysaid diaphragm in response to a predetermined pressure differential between said 'chambers to -free said dogs and release said pin for firing movement, and a capillary tube in said vfirst chamber connecting ythe interior thereof with the ambient atmosphere. 4. In a pressure-differential actuated fuse, a tubular casing, first 4and second walls closing respective ends of said casing, a yflexible gas-tight diaphragm in said casing and, in cooperation with said walls, dividing said casing Airito -first and second chambers, a firing pin axially slidable 'in and Athrough said second wall from a retracted to a 'firing position, spring means urging said pin into firing position, a plurality of dogs carried by said second wall and pivotable from a 'first position engaging and holding said pin 'reti-acted, "to a second position freeing said pin -for firing movement, safety means carried by said dia- 'phra'gm engaging and holding all said dogs in first posi- 'tion 'when said diaphragm is undefiected, said safety 'means 'being moved by said diaphragm to release said dogs Vwhensaid 'diaphragm is defiected Vin response to a predeterminedipre'ssre difference between said chambers, and aflev'erarm weighted Yat one end and connected with VSaid diaphragm at the other, whereby to oppose movement of said diaphragm otherwise caused by shocks and jars.

v5. 'In 'a 'pressure-differential responsive fuse, a closed casing, a partition in 'said casing comprising a fiexible 'gas-tight diaphragm dividing said casing into first and second chambers, a firing `pi`n 'slidably mounted in said L'second chamber from 'a 'retractedto a firing position,

spring means urging said 'pin into firing position, avplurality of dogs mounted about sa'id pin for pivotal kmove- 'merit in respective planes radially of said Ypin from a 'first position engaging Aand 4holding said pin retracted, to a second position releasing 'said pin for ring movement, `a ring secured to said diaphragm, said ring enlg'agin'g said dogs to hold the same in first position when lsaid diaphragm -is in undefiected position and movable 'with said diaphragm to release said dogs in response to 'a predetermined pressure difierential between said #chanbers, 'and valve means `operable to selectively open 'o'r close lsaidifirst chamber to the -ambient atmosphere.

6. A fuse as recited in claim 5, a second exible diaphragm in the wall of said irst chamber, and bimetallic thermostatic means in said iirst chamber and connected with said second diaphragm to ex the same in response to temperature changes in said first chamber and thereby maintain substantially constant the pressure therein.

7. A fuse as recited in claim 5, said dogs being two in number and on diametrically opposite sides of said ring pin, a iirst U-shaped safety pin with its bight portion outside said casing and its legs extending through apertures in said casing to engage and hold respective dogs in iirst position, a second safety pin extending through an aperture in said casing and engaging and holding said tiring pin retracted, said second safety pin having a bent end normally held between said casing and bight portion of said first safety pin.

10 8. A fuse as recited in claim 7, a tongue having one end secured to said bight portion, and a band encircling said casing and simultaneously holding said tongue against said casing and sealing oif communication between said valve means and the ambientatmosphere.

References Cited in the file of this patent UNITED STATES PATENTS 583,633 Roesch June l, 1897 1,617,674 Dieter Feb. l5, 1927 1,830,869 Charles Nov. 10, 1931 2,330,873 Doe Oct. 5, 1943 2,422,548 Hebard June 17, 1947 FOREIGN PATENTS 165,108 Great Britain June 30, 1921

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