US2794395A

US2794395A - Material breaking cartridge

Info

Publication number: US2794395A
Application number: US242724A
Authority: US
Inventors: James C Hesson; John L Smith
Original assignee: Cardox Corp
Current assignee: Cardox Corp
Priority date: 1951-08-20
Filing date: 1951-08-20
Publication date: 1957-06-04
Anticipated expiration: 1974-06-04
Also published as: FR1087044A; BE522571A

Description

June 4, 1957 J. c. HESSON ET A1.

MATERIAL BREAKING CARTRIDGE 5 Sheets-Sheet l Filed Aug. 20, 1951 June 4, 1957 J. c. HEssoN ET A1.

MATERIAL BREAKING CARTRIDGE 5 Shets-Sheet 2 Filed Aug. 20, 1951 d m@ O mm ES d m w Bx% mm June 4, 1957 1. c. HEssoN ET A1.

MATERIAL BREAKING CARTRIDGE 3 Sheets-Sheet 3 Filed Aug. 20. 1951 United States aten-t idee 2,794,395 Patented June 4, 1957 MATERIAL BREAKING CARTRIDGE James C. Hesson, Riverdale, and John L. Smith, Chicago, Ill., assignors to Cardox Corporation, Chicago, ill., a corporation of Illinois Application August 20, 1951, Serial No. 242,724

34 Claims. (Cl. 102-25) This invention relates to new and useful improvements in material breaking cartridges of the type employing a high pressure gas as the work performing medium.

The use of cartridges employing a highly compressed charge of air or other gases for breaking down materials, such as coal in mines, is well-known and has been widely practised in recent years. The gaseous charge for such cartridges may be introduced after the cartridge is positioned for operation or may be produced Within the cartridge at the time of operation by expansion of a previously introduced liquefied gas or by burning or heating a previously introduced solid of a type which will thereupon produce a large volume of gas. In any event, the efficiency of this type of operation is dependent to a considerable degree upon the speed and extent of opening of the valve employed for effecting the release of the charge of compressed gas and upon the ease with which the cartridge can be reconditioned for subsequent use.

The primary object of the invention is to provide a compressed gas material breaking cartridge from which the material breaking charge can be quickly and completely released and which can be reconditioned for subsequent and repeated use with a minimum of time and effort.

A further important object of the invention is to provide a compressed gas material breaking cartridge having a release valve mechanism, located entirely in the discharge end of the cartridge, which will operate automatically at the desired work performing pressure and which may be quickly reconditioned for subsequent use.

Another important object of the invention is the pro- Vision of a material breaking cartridge that may be charged with gas at a continually increasing pressure, and isV provided with a valve mechanism which will operate automatically to quickly eifect release of the complete material breaking charge when the pressure of the gas reaches a predetermined value and which may be quickly reconditioned for use to elect release of a subsequent charge at the same predetermined pressure.

Another important object of the invention is to provide a compressed gas material breaking cartridge, the discharge from which is controlled by a rupturable member which will operate automatically to effect discharge only at the desired work performing pressure, the rupturable member being readily movable into a number of different positions for repeated use to recondition the cartridge for subsequent operations and being readily replaceable by a like member which in turn may be repeatedly used for a plurality of operations.

A still further object of the invention is to provide a material breaking compressed gas cartridge having a charge releasing valve mechanism which will operate automatically to etfect discharge of the gas when the pressure of the charge exceeds the rupture strength of an element of the valve mechanism, the rupturable element being both movable and replaceable to quickly recondition the valve mechanism for a multiplicity of sub- ,sequent charge releasing operations.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like reference characters are employed to designate like parts throughout the same,

Figure l is a perspective View of one form of material breaking cartridge embodying `the invention,

Figure 2 is a longitudinal sectional view of the cartridge illustrated in Fig. 1,

Figure 3 is a transverse sectional View taken on line 3--3 of Fig, 2,

Figure 4 is a longitudinal sectional View of the discharge end portion of a modified form of material breakring cartridge,

Figure 5 is an end elevational view of the cartridge illustrated in Fig. 4,

Figure 6 is a transverse sectional view taken on line 6-6 of Fig. 4,

Figure 7 is a longitudinal sectional View of the discharge end portion of a further modified form of material breaking cartridge,

Figure 8 is a transverse sectional view taken on line 8 8 of Fig. 7,

Figure 9 is a longitudinal sectional view of the discharge end portion of a still further modiiied form of material breaking cartridge,

Figure 10 is an enlarged sectional View taken on line 10-10 of Fig. 9, and

Figure l1 is a transverse sectional view taken on line 11-11 of Fig. l0.

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments of the invention, and rst particularly referring to Figs. l to 3, inclusive, the reference character 12 designates a cartridge body member having a chamber 13 therein from which the compressed gas charge is to be released. One end of the body member 12 is closed by a charging cap 14 which is threadedly connected to the body member. The charging cap 14 has an inlet opening 15 formed in its end wall and a conical seating surface 16 surrounding the outer end of the opening. An internally and externally threaded annular projection 17 extends axially outwardly from the end of the charging cap 14 in coucentric relationship with the conical seating surface 16.

A guard ring 18 and a coupling nut 19 are slipped successively over the end of a compressed gas feed line 21 through which gas is to be fed into the chamber 13. The nut 19 is provided with an axially located bore 22 which is tted onto the outer surface of the feed line 21 and the inner end portion of the bore 22 is flared outwardly to yform a conical surface 23 opposite the conical seating surface 16. When the coupling nut 19 is threaded into the annular projection 17 the end of the feed line 21 is llared outwardly and gripped between the conical surfaces 16 and 23. The guard ring 18 is then threaded onto the projection 17 to form a protecting wall around the coupling members.

The illustrated charging cap 14 and its associated coupling elements comprise only one of several well-known methods of providing a charge of compressed gas in the chamber 13 and it is to be understood that applicants invention is not to be limited to the particular means disclosed. It is contemplated that the invention, also, may be used with equal efficiency .in those circumstances where the charge of compressed gas is introduced to the chamber 13 in the form of a liquefied gas or a solid which will form a large volume of gas when burned or heated.

The end portion `of the 'body member 12 opposite the charging cap 14 is internally shouldered -at 24 and is provided with threads 25 between the shoulder 24 and the adjacent end `of the cartridge body. An ladaptor member 26 is threaded into the end of the body member 12 into sealing engagement with the gasket 27 positioned on the shoulder 24. The outer end portion ofthe adaptor member 26 is externally threadedat 28 and the end edge forms an annular valveseat 29. Y

A discharge section 31, formed with an internally threaded inner end portion 32, is threaded ontol the end of the `adapter and is provided with a circumferentially alined yrow of discharge or release ports 33 which are closely 'adjacent to the valve seat 29 .and are of sucient number and total cross-sectional area to effect rafpid release of the gas from the cartridge -chamber 13. The; discharge section 31 is of tubular construction and has: an

inner diameter slightly greater than that ofthe, annu-lar valve seat I29. v Y

A piston type main valve 34. i sl positioned in` thee discharge section 31 for longitudinal. movement relative thereto between its 4seated and fully opened posit-ions.

The valve 34 is of hollow cylindrical construction to reduce its weight to a minimum and has an open inner end `and a closed outer end. The` open inner end of the valve 'is beveled at its periphery to provide a seating lsurface 35 for engagement with the valve seat 29. The closed outer endv portion of the. valve has a packing ring 36 positioned in the circumferential groove, 37 Vtoprovide sealing engagement between the valve andthe innersurface of the `discharge sction 31 at all times. The valve 34, therefore, provides a sealbet-ween the discharge ports 33 and the interior `of the discharge section-and, when in its closed position, between the discharge ports and the charge release chamber 13. Y Y

A plunger 38 is positioned in the oppositev end of the discharge lsection 31 froml the main valve 34 for longitudinal movement relative to the section, 'The plunger 38 isV formed with a circumferential groove 39 for receiving a packing ring 41V to provide sealing engagement between the plunger `and the inner surface of the discharge section 31. Positioned between the main valve 34 and plunger 38 is a spring 42 which reacts to urge the valve and plunger toward opposite ends of the discharge section 31.

Threadedly connected to the outer end of the discharge section 31 is a double-ended venting cap 43 having .an intermediate wall, 43a for retaining the plunger 38` within the, discharge section. The wall 43a is provided with an axially located aperture 44 for receiving an axial. projection 45 on the outer end of the plunger 38. The projection 45 is movable in the aperture 44 to a position at which its outer end extends slightly beyond the outer face of the venting cap wall 43a.

Formed within the dis-charge section 31 and between the movable main valve 34 and plunger 38 is a control chamber 46 which is in communication with the charge release chamber 1-3 through an aperture 47.' in the closed outer end of the main valve 34. A passageway 48 ex tends axially through the body portion of the plunger 38 and its projection 45. The diameter of theapert-ure 47 in the valve 34 is less than that of the passageway 48 in the plunger 38 for reasons that later will be described. Ratios of the .aperture diameter tothe passageway diameter ranging from one-half to one`third havebeen found to be satisfactory.l

The outer end portion 49 -of the venting cap 43 is internally threaded and is provided withdiametric-ally positioned rectangular slots 51 which are located adjacent the wall 443a and have their major ydimension parallel tosaid wall. rA 'shear strip 52 of any suitable rupturable material, such as brass, steel, fiber, or the like, is inserted through the slots 51 across the end ofv the passageway 48 in vthe plunger 38. The strip- 52 bearsagainst the outer end of the projection 45 on the plunger 38 and 'is loosely clamped in this position by a plug 53 which isthreaded into the end portion 49. vThe plug 53 is threaded into the cap portion 49 until it` bears against lthe strip 52l and movesl the.' strip and the plunger 38V a'slight ldistance against the-pressureof the spring 42. Y

The plug 53 is formed with an axially located passageway 54 of equal size and in alinement with the passageway 48 in the plunger 38 von the opposite side of the strip 52. The outer end of the passageway 54 intersects a transverse passageway 55 through the `outer end of the plug S3. Radial ports 56 extend from the passageway 54 to the threaded peripheryl of the plug 53 to blow dust out of the threads and similar ports '57 extend` from the passageway 54 into the space between the inner end of plug 53. and the venting cap wall 43a. to blow ldust out of the space.

The operation `of the lcartridge illustrated in Figs. ll to 3, inclusive, when compressed air, or other gas, is employed, will be described as follows:

The cartridge, in an uncharged condition Ibut connected to a suitable source of supply of compressed air, or other gas, by the feed line 21, is placed in the previously prepared drill hole formed in the working face of the material to be broken down, `such 'as coal in a mine. At this time, the charge release chamber 13 of the cartridge body 12. is sealed from the discharge ports 33 by the engagement of the Vmain valve 34 with its lseat 29 andlfby the packing ring 36. The charge release chamber 13, however, is in communication with the control chamber 46. through the aperture 47 in the valve.

The compressed air Idelivered to the charge release chamber 13 will rapidly build up` the pressure therein to the desired work performing pressure. During this charging of the chamber 13, compressed air is permittedV to flow into the control chamber 46 through the aperture 47 in the valve 3.4. The pressures in the chargeV release cham'ber 13 and the control chamber 46, therefore, will be substantially equal during charging, At this time, the main valve 34 will Ibe maintained in its seated or closed position by the force yof the spring 42 and the differential force acting upon the opposite ends `of the valve. In other words, lthe effective surface area of the valve 34 exposed to the pressure in the control chamber 46 is greater than the effective surface area of the valve exposed to the pressure in the charge release chamber 13 to that the forces acting upon the valve 34 are unbalanced in a `direction to maintain the valve in its closed position. These elective surface areas on opposite endsof the valve 34 may be considered as being equal to the cross-sectional area ofthe Vcontrol chamber 46 .and the cross-sectional area of the valve seat 29, respectively, with each of the erossfsectional areas Ibeing reduced by the crossrseetionalarea of the aperture 47.

When thecharge releasegandcontrol chambers 13 and 4.6,. respec: tivelyv,l have' received a suicient volume of gas to raisethe pressuresl therein to the desired work perfQrming valuefthe ypressure of the gasl in the Vcontrol chamber will cause theexposed portion of the strip 52 to be, shearedvand blown through the passageways 54 and A55l to clear these passageways for the proper venting of the control chamber.- lt will he lunderstood; that the pres- Sugr at which shearingV occurs will be controlled` by the strength, character and thickness .of thematerial from which `the strip is made. Ditferent types of strips 5.2 may, therefore, be employed to cause` the cartridge to discharge atany work performing pressure desired.

When. the exposed-portion of the strip 52 is sheared, the

ycontrol chamber .46 is opened directly to the passageways 54and 5,5 of the plug 53 so that the compressedV gas will flow through these passageways to quickly reduce the pressure in the controli chamber. This reduction inthe pressure` inY the control chamber 46 permits the pressure of'the: compressed-gas in the charge release chamber'r 13 to unseat and completely'open the valve 34 and release the gas charge Vthrough the discharge ports 33. Upon discharge of the cartridge, the Vflow of gas through the'feed line V21 willbe cut off by-an operator at a remote point inthe-line.

The strip 52, which is initially clamped in position in the slots 51 only by'the pressure ofthe spring 42,Y is

clamped in position with a considerably greater force during charging of the cartridge by the pressure of the gas in the control chamber 46 acting on the plunger 38. When the cartridge is discharged, however, the pressure in the control chamber 46 is reduced to atmospheric pressure and the strip 52 is again clamped only by the pressure of the spring 42 on the plunger 38. The plug 53, therefore, may be loosened or moved outwardly by hand to permit the plunger 38 to move outwardly until it bears against the wall 43a so that further movement of the plug will release the strip 52 which then may be moved longitudinally in the slots 51 to position an unsheared portion across the

alined passageways

48 and 54. This repositioning of the strip 52 may be facilitated by marking or indexing the strip and the length of the strip may be such as to permit its use for any reasonable number of cartridge operations, such as from two to six. When the strip has been repositioned, the plug 53 is again tightened to move the strip 52 and plunger 38 a sufficient distance for the strip to be clamped by the action of the spring 42 on the plunger. At this time, the main valve 34 having been reseated by the spring 42, the cartridge is reconditioned for a subsequent operation.

As was previously pointed out, the passageway 48 is of larger cross-sectional area than the aperture 47 so that the venting of gas from the control chamber 46 will greatly exceed the rate of iioW of gas through the aperture 47. To further increase the rapidity of the venting of the control chamber 46, the inlet end of the passageway 48 is rounded to provide a better discharge coeflicient.

Referring now to Figs. 4 to 6, inclusive, for a detail description of this modification of the invention, the cartridge body member 12 and its attached adapter member 26 are substantially identical to those illustrated in Figs. 1 to 3, inclusive, and, for that reason, the same reference characters have been applied to the corresponding parts.

A discharge section 58, having its internally threaded inner end portion 59 connected to the adapter member 26 by the threads 28, is provided with two spaced circumferential rows of discharge or release ports 61. As illustrated in Fig. 6, there may be six uniformly spaced ports in each row with the ports of each row circumferentially displaced from, or out of alinement with respect to, the ports of the other row. It will be noted that the discharge section 58 is of greater length than the discharge section 31 of Fig. 2. The reason for this will appear as as the description proceeds.

A piston type main valve 62, positioned in the discharge section 58 for longitudinal movement relative thereto, is of sufiicient length to cover both of the rows of ports 61. Otherwise, it is constructed the same as the valve 34 of Fig. 2, and the same reference characters will be applied to the corresponding parts.

A plunger 66, positioned in the opposite end of the discharge section 58 from the main valve 62 for longitudinal movement relative to the section, is of the same general construction as the plunger 38 of Fig. 2, the only difference being that the main body portion is reduced in axial dimension. Therefore, the same reference characters will be applied. A spring 69, positioned between the main valve 62 and the plunger 66, reacts to urge the valve and plunger toward opposite ends of the discharge section 58.

Threadedly connected to the outer end of the discharge section 58 is a double-ended wenting cap 71 which is of identical construction to the venting cap 49 of Fig. 2 and the same reference characters have been applied thereto.

Formed within the discharge section 58, between the movable main valve 62 and the plunger 66, is a control chamber 74 which is of suflicient length to accommodate the main valve 62 when the latter is in its fully opened position.

This cartridge, also, is provided with a shear strip 52 which functions in the same manner as the shear strip of the cartridge of Fig. 2. Cooperating with the shear strip 52 '66 for clamping the shear strip 52.

is a plug 81 which differs structurally from the plug 53 of Fig. 2 only by having a reduced cylindrical projection 82 which cooperates with the projection 45 of the plunger Therefore, the same reference characters have been applied to the other corresponding parts.

The operation of the cartridge illustrated in Figs. 4 to 6, inclusive, is identical to that of the cartridge illustrated in Figs. l to 3, inclusive, and, for that reason, wll not be described. It will be noted, however, that because the discharge section 58 is provided with a double row of discharge ports 61 it is necessary for the main valve 62 to move a greater distance into the control chamber 74 to completely open the discharge ports.

The modification of the invention illustrated in Figs. 7 and 8 employs a body member 12, adapter member 26, discharge section 31, venting cap 43, and shear strip 52, which are substantially identical to those illustrated in Figs, l to 3, inclusive, and the same reference characters have been app-lied to corresponding parts of each.

The main valve 85 is of the piston type and is positioned in the discharge section 31 for longitudinal movement relative thereto between its seated and fully opened positions. The valve 85 is of hollow cylindrical construction and has a closed inner end and an open outer end. The inner closed end of the valve 85 is beveled at its periphery to provide a seating surface 89 for engagement with the valve seat 29. The length of the valve 85 is such that its open outer end portion lies on the opposite side of the discharge ports 33 from the seating surface 89. The outer open end portion of the valve 85 is formed with a circumferential groove 91 for receiving a packing ring 92 to provide sealing engagement between the valve and the inner surface of the discharge section 31 at all times. The valve 85, therefore, provides a seal between the discharge ports 33 and the interior of the discharge section 31 and, when in its illustrated closed position, between the discharge ports and the chamber 13.

The plunger 87 is positioned in the opposite end of the discharge section 31 from the main valve 85 for longitudinal movement relative to the section. One portion of the plunger 87 forms a piston 93 having a circumferential groove 94 for receiving a packing ring 95 to provide sealing engagement between the plunger and the inner surface of the discharge section 31. The body portion of the plunger 87 extends inwardly from the piston 93 into the open end portion of the main valve 85. Positioned over the body portion of the plunger 87 and between the valve 85 and the plunger, is a spring 86 which reacts to urge the valve and plunger toward opposite ends of the discharge section 31. A projection 96 extends outwardly from the piston portion 93 of the plunger 87 through the aperture 44 in the venting cap 43 and is adapted for movement to a point slightly beyond the end of the venting cap.

Formed within the discharge section 31 and between the movable main valve 85 and plunger 87 is a control chamber 97 which is in communication with the charge release chamber through the aperture 98 in the inner closed end portion of the main valve 85. The body portion of the plunger 87, its piston 93 and its outwardly extending projection 96 have an axial passageway 99 extending therethrough. The diameter of the aperture 98 in the valve 85 is smaller than that of the passageway 99. Ratios of aperture diameter to passageway diameter ranging from one-half to one-third have been found to be satisfactory. Radial ports 101 extend outwardly from the passageway 99 in the plunger 87 to that portion of the control chamber 97 which surrounds the body portion of the plunger.

The plug 88 is threaded into the outer end portion 49 of the venting cap 43 to bear against the shear strip 52 and to move the strip and its engaging plunger projection 96 a slight distance against the pressure of the spring 86 and to clamp the strip in its proper position. The plug 7 8&1 is tonnen with an. axially located passageway 10,2., the inner. end portionV of which is ef equal. size and in alinemjentwiih thelpllunger passageway 99 on the opposite side ofthe strip/.152. The outer end portion of passageway l 1.02 is enlarged and intersects a transverse passageway 103 through the outer end portion of the plug 88. Radial ports 1051 extend, from the passageway 102 to the engaging ,threaded surfaces,v of the plug 88 and the cap end P QItion 49,y to blovsl .dust out of the threads.

The operation of the cartridge illustrated in Figs. 7 and 8 is identica-1 t9 that of the cartridge illustrated in Figs, 1 to, 3, inclusive, and will not be described. It will b e noted, however, that the radial ports 101 in the body portion of the plunger 87 facilitate the rapid venting of the airfrOIn the, control chamber 97,7 which would otherwise be inhibited; by the elongated body portion of the plunger. 87,.

Referring no w to Figs. 9; tov 11 inclusive, wherein is illustrated a further modification of the invention, it will be noted that thecartridge body member 12, adapter member 26, and discharge section 31 are substantially identical .to` those illustrated ini Figs. 1 to 3 inclusive, and the same reference characters have been applied to the corresponding parts thereof.

A venting extension 105, having an internallythreaded inner end portion 106 screwed onto the outer end portion of the discharge section 31, provides a circumferentially alined row of venting ports 107 closely adjacentY to. the outer end of the discharge section 31. The Vventing extension 105 is of tubular construction and has `an inner diameter slightly greater than that of the discharge section 31 so that the end of theA discharge section is slightly otset inwardly from the inner surface of the venting extension to form a pilot valve seat 108.

A piston type main valve 109 is positioned in the discharge section 31 for longitudinal movement relative thereto between its seated and fully opened positions. The main valve 109 is of hollow cylindrical construction and has an open inner end and a closed outer end. The open inner end of the valve is beveled at its periphery to pro'- vide a' seating surface 111 for engagement with the valve seat 29. The length of the valve 109 is such that its closed outer end portion lieson the opposite Vside of the discharge ports 33 from the valve seat 29. The closed outer end portion of the valve 109 is formed with a circumferential groove 112y for receiving a', packing ring 113, to provide sealing engagement between the valve and the inner surface of .the discharge section 31 at all times. VThe valve 109, therefore, provides a lseal between the discharge ports 33 and the interior of the discharge section 31 and, when in its closed position, between the discharge ports and the chamber 13.

Positioned in the discharge section 31 in engagement with the outer end of the main valve 109 is a spring 114 which is retained in the discharge section by a piston type pilot valve 115. The spring 114 is compressed between and reacts in opposite directions against the main valve 109 and the pilot valve 115 to urge the'main and pilot valves, respectively, toward and away from their

valve seats

29 and 108.

The pilot valve 115 is positioned in the venting ex`- tension 105 for longitudinal movement relative thereto between its seated and full opened positions and is of hollow cylindrical constructions similar to that of the main valve 109. The inner open endv portion of the pilot valve 115 is beveled at its periphery to provide a seating surface 1,16 for engagement with the pilot valve seat 108. The outer closed end portion of the valve 115 is formed with a circumferential groove 117 for receiving a packing ring 118 to provide sealing engagement between the pilot valve and the inner surface of the venting section 1 05 at all times. The pilotyalve 115, therefore, provides a seal between the venting ports 107 and the interior of venting section `1.05 and, whenincits close'dpositienfbetween the venting ports and the-interior of thedischargeseetion 51,

A spring; ,1.19r is petitioned in. the venting section 1.0.5..

with one of, itsY endfportions engaging the outer end of the` gilet taire. 1.15 and e, plunger 121 is positined in. the venting! Section. for engagement with the Opposite end of thef spring. The spring4119,k is, therefore, compressed between and reacts in opposite directions against the pilot valve 11,5; and the plunger 121 toV urge the valve and plunger toward opposite ends of the venting section 105.- The spring 1 -1 f9i s somewhat stronger than the spring 114 so that the unbalanced forces acting upon the pilot valve will cause the valve to move into the position in which the seating surface 116 engages the valve seat 108. i

The, plunger 12,1 is adapted for longitudinal movement in the venting section 1 05 and is formed with a circumferential groove `122 Vfor receiving a packing ring 123 to provide scaling engagement between the plunger and the inner Surface Qt the "enting Section- Tnreadedly connected to; the outer end of the venting section 10S is a doubler-ended venting cap 124 which retains the plunger 121 within the venting section. The

venting cap 124A is provided with an axially located, in-l ternally threaded pocket 12,5 extending through its outer end portion 12451. Theinner reduced portion 125a of the pocket 12,5 is smooth and receives a projection 126 on the outerend of the plunger 121 which is movable to a position at which its, outer end extends slightly into the threaded. portion 0f; the pocket.

Diarnetrica-lly opposite, outwardly opening recesses 127 are formed in4 thev sidesv of the cap endV portion 124a and are connected with the threaded portion of the pocket 125. by the slots 12,8, as best illustrated in Fig. l0. On opposed .Sides of; each recess 12,7, the cap 124 is cut away te provide the webs 12.9.

The recesses 127 are provided to removably house the supply and take-up reels 139 which are rotatably supported bythe shafts 137I that are insertable in the alined bearing openings 138 formed in the webs 129. The hubs o the reels 13,9 are provided with suitably attached keys 141. The shafts4 13,7 are formed with keyways to receive the keys 141. It will be appreciated that the shafts 137l may be inserted through their bearing openings 138, and through the bores of the reel hubs to mount the reels `1.39. in the recesses 127. The removal of the shafts 1 37 will permit the reels 139 to be removed from the recesses. Each one of the shafts 137 is provided with a squared end 143g that may be engaged by a suitable key, or the like, for effecting itsV rotation.

This reel' assembly is employed for supplying the strip of rupturable material; to the illustrated position between the cooperating end portions of the plunger 121 and the plug 142 s o that longitudinally spaced portions may be positioned between the adjacent ends of the

alined passageways

136 and 1,43. To accomplish this desired result, Vone of the reels 1 39 has wound thereon va coil of the rupturable strip 140 when it is inserted in its recess 127 and secured therein by its supporting shaft 137. rlhe other reel 139 will function as a take-up for the strip as longitudinally spaced portions of the latter are subjected to the shearing action which results from the ventingl of the'control chamber section 132.

The extremities of the rupturable strip are suitably anchored to'the hubs of the reels in the manner best illustrated in Figs. l0 and 11. After the rupturable strip 140 has been transferred from the supply reel to the take-up reel, the latter reel may be removed from its recess 127 and another reel, with a supply of strip material coiled thereon, may be substituted. The original supply reel 139 then may be used as the take-up reel for the new strip of material.

The cartridge, assembled as described above, has formed within the discharge and venting

sections

31 and 105, respectively, and between the main valve 109 and plunger 12.1 a. Control chamber 13.1 which iS divided into an outer or pilot section 132 and an inner main section 1,33 by the pilot' valve 11,5. The main section 133 of the control chamber is in communication with the charge release chamber 13 through an aperture 134 in the main valve 109. The main and pilot sections 133 and 132, respectively, are in communication with each other through an aperture 135 formed in the pilot valve 115. A passageway 136 extends axially through the body portion of the plunger 121 and its projection 126. The diameters of the apertures 134 and 135 in the main valve 109 and pilot valve 115, respectively, are smaller than that of the passageway 136 in the plunger 38 for reasons that later will be described. Ratios of aperture diameters to the passageway diameter ranging from one-half to one-third have been found to be satisfactory.

A plug 142 is threaded into the outer portion of the pocket 125 into contact with the strip 140 to move the strip and its engaging plunger projection 126 a slight distance against the pressure of the spring 119. The plug 142 is formed with an axially located passageway 143 of equal size to and in alinement with the passageway 136 in the plunger 121. The outer end of the passageway 143 intersects a transverse passageway 144 through the outer end of the plug 142.

The operation of the cartridge illustrated in Figs. 9 to l1, inclusive, will be described as follows:

The cartridge, in a condition for being charged with compressed air or other gas, is placed in a previously prepared drill hole formed in the working face of the material to be broken down, such as coal in a mine. At this time, the charge release chamber 13 of the cartridge body 12 is sealed from the discharge ports 33 by the engagement of the main valve 109 with its valve seat 29 and by the packing ring 113, and the main section 133 of the control chamber 131 is sealed from the venting ports 107 by the engagement of the pilot valve 115 with its valve seat S and by the packing ring 118. The :.lined

passageways

136 and 143 in the plunger 121 and plug 142, respectively, are sealed from each other by the shear strip 140. The charge release chamber 13 is, however, in communication with the main and pilot sections 133 and 132, respectively, of the control chamber 131 through the apertures 134 and 135 in the main valve 109 and pilot valve 115, respectively.

The compressed air in the charge release chamber 13 is rapidly built up to the desired work performing pressure. During this charging of the chamber 13, cornpressed gas is permitted to iow into the main and pilot sections 133 and 132, respectively, through the apertures 134 and 135. The pressure in these sections of the control chamber 131, therefore, will be substantially equal to the pressure in the charge release chamber 13 at all times. The main valve 109 will be maintained in its seated or closed position by the force of the spring 114 and the ditferential force acting upon the valve. In other words, the elfective surface area of the valve 109 exposed to the pressure in the main section 133 of the Control chamber 131 being greater than the effective surface area of the valve exposed to the pressure in the charge release chamber 13, the forces acting upon the valve 109 are unbalanced in a direction to maintain the valve in its closed position. The pilot valve 115, also, will be maintained in its seated or closed position by ther force of the spring 119 and the differential force acting upon opposite sides of the Valve. This differential force on Valve 115 is due to the greater effective surface area exposed to the pressure in the pilot section 132 of the control chamber 131 than the effective surface area of the pilot valve exposed to the pressure in the main section 133 of the control chamber.

When the charge release chamber 13 and both sections of the control chamber 131 have received a sufficient volume of gas to raise the pressures therein to the desired Work performing value, the pressure of the gas in the pilot section 132 of the control chamber will cause the exposed portion of the strip 140 to be sheared and blown out through the

passageways

143 and 144. Inasmuch as the strip 140 is wrapped onto and olf of the reels 139, the strip is formed of ductile or llexible material, the shear strength of which is necessarily limited. This limited shear strength is, however, compensated for by a reduc tion in the diameters of the

passageways

136 and 143 so that the cartridge will be discharged when the pressure therein reaches the proper value.

When the strip 140 is sheared, the pilot section 132 of the control chamber 131 is vented through the

passageways

143 and 144 in the plug 142 to quickly reduce the pressure in the pilot section. This reduction in the pressure permits the pressure of the compressed gas in the main control section 133 to open the pilot valve 115 to release the gas from the main section through the venting ports 107. This venting of the main section 133 will quickly reduce the pressure therein to permit the pressure of the gas in the charge release chamber 13 to open the main valve 109 for release of the gaseous charge through the discharge ports 33. After the gas in the charge release chamber 13 has been discharged, the pressure in the charge release chamber and both sections of the control chamber 131 will be at atmospheric pressure and the springs 114 and 119 will cause the main valve 109 and the pilot valve 115, respectively, to be returned to their seated or closed positions.

The strip 140, which is initially clamped in position across the

alined passageways

136 and 143 only by the pressure of the spring 119, is clamped in position with a considerably greater force during charging of the cartridge by the pressure of the gas in the pilot section 132 of the control chamber 131 acting on the plunger 121. When the cartridge is discharged, however, the pressure in the pilot section 132 is reduced to atmospheric pressure and the strip 140 is again clamped only by the pressure of the spring 119 on the plunger 121. The plug 142, therefore, may be loosened or moved outwardly by hand to permit the plunger 121 to move outwardly until its body portion bears against the cap 124. Further movement of the plug 142 then will release the strip 140. The strip 140 thereafter may be moved longitudinally through the slots 128 by rotation of the take-up reel 139 to position an unsheared portion of the strip across the

alined passageways

136 and 143. This repositioning of the strip 140 and tightening of the plug 142 to move the strip and plunger 121 a suicient distance for the strip to be clamped by the action of the spring 119 reconditions the cartridge for a subsequent operation.

As was previously pointed out, the passageway 136 is of larger crosssectional area than the aperture 135' in the pilot valve so that venting of the gas from the pilot section 132 will greatly exceed the rate of ow of gas through the aperture 135. Similarly, the flow of gas through the venting ports 107 when the pilot valve 115 is opened will cause the main section 133 of the control chamber to be vented at a rate greatly exceeding the flow of gas through the aperture 134 in the main Valve 109.

lt will be appreciated that the venting caps 49 of the different cartridges illustrated in Figs. l to 8, inclusive, are each interchangeable with the venting cap 124 of the cartridge illustrated in Figs. 9 to ll, inclusive. In other words, the venting cap 124, with its supply and take-up reels for the strip of rupturable material, may be used with any one or all of the different cartridges illustrated in Figs. l to 8, inclusive, while the venting caps 49 of these last mentioned cartridges may be employed with the cartridge of Figs. 9 to 1l, inclusive.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred `examples of the same and that various changes in the shape, size, and arrangement of parts may be resorted `to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, we claim:

' 1. In combination, a cartridge having a chamber from whichl a. material breaking charge of compressed gas. is to be released, lateral gas charge release ports, and acontrol chamber arranged; successively longitudinaliyy of said, cartridge, a valve. for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gasin said control rand release chambers with. a greater effective surface area exposed to said control chamber than to said release chamber, means for equaliaing, the gas pressures inthe release and control chambers, resilient means urging said valve into its closed position, and venting means responsive solely to an increase in the gas pressure in the control chamber to a predetermined value for automatically releasing the gas from said control chamber tocause the gas in the release chamber to open the valve, said venting means comprising an elongated strip of rupturable material, and means for clamping, said strip to expose a selectable portion of it to the pressure of the gas in said control chamber to cause the exposed portion to. be sheared by the control chamber pressure when said predetermined value is reached.

2 VIn combination, a cartridge having a chamber from which a material breaking charge of compressed gas is to be released, lateral gas charge release ports, and a control chamber arranged successively longitudinallyl of said cartridge, a valve for controlling the release olf the gas charge from said gas release chamber to the release ports and'being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than to s aid release chamber, means for equalizing the gas pressures in the release and control chambers, resilient` meansurging` said valve into its closed position, and venting means for automatically releasing the gas from said control chamber to cause the gas in the release chamber to. open the valve when the pressure in said chamber reaches a predetermined value, said venting means comprisingV an elongated strip of rupturable material, and means for clamping said strip to expose a limited portion of the latter to the pressure of the gas in said control chamber to cause the exposed portion to be sheared bythe control chamber pressure when said predetermined'v value is reached, said clamping means being adjustable to release and reclamp the strip so that the latter may be. moved to successively expose other unsheared limited portions to the control chamber pressure to condition the ventingl means for repeated operations of the cartridge.

3, In combination, a cartridge having a chamberl from which a material breaking charge of compressed` gas is to be released, lateral gas charge release ports, and; a control chamber arranged successively longitudinally; of said cartridge, a valve for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gasV in said control and release chambers with a greater-effective surface area exposed to said control chamber thanto said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into itsvclosed position, and ventf ingmeans for automatically releasingthe2 gasfrom said control chamber to cause the gas in the release chamber to open the valve when the pressure in saidcharnbersl reaches a predetermined value, said venting meanscorri-v prising .an elongated strip of rupturable material, and means for clamping said strip to expose a limited' portion of the latter to the pressure of the gas in saidcontrol chamber to cause the exposed portion to be sheared by the control chamber pressure when said predetenniued.

value is reached, said clampingl means comprising one part that is subject to thecontrol chamber pressure sov asto vary the clamping force applied tol the. stripA sub? stantially in proportion to said pressure and at,secondipart-r manually adjustable to. release. andi reclami)I theV strip, Whensaid'one part is subjected to alowcontroljchamber pressure, so said strip` may; be moved to successively expose otherunsheared limited portions to the control chamber pressure toV conditiony the venting means for repeatedoperations ofthe cartridge.

4. In combination, a cartridge having a chamber fro which a material breaking charge of compressed gas is to be released, lateral gas charge release port-s, and a control chamber arranged successively longitudinally ofy sai-d. cartridge, a valve forcontrolling the release of the gas charge from said gasrelcase chamber to the release ports and being exposedto the pressure of the gas in saidA control and release chambersfwith a greater effective surface ,area exposed to said control chamber than to said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the gas from said conf-, trol chamber to cause the gas in the release chamber to open the `valve when the pressure in said chambers reaches a predetermined value, said venting means comprising au Velongated strip of rupturable material, means movable into clamping engagementlw-ith said strip for maintaining the strip in ar'positionto expose a limited-portion thereof to the pressure ofthe gas in said control chamber and to cause the exposedrportion to be sheared by the controlcharnber pressure when said predetermined valuel is reached, resilient means urgingsaid clamping means in a direction for loosely clamping said strip in said position, means responsive., to the pressure in said control chamber for increasingthe clamping forces of the movable means as the pressure in the chamber is increased, and means for disengaging said strip from -said movable means when the lstrip is iny itsloosely clamped condition for movementof the strip to expose a different longitudinally spaced portion ofthe latter during each succeeding operation ofthe cartridge.

V5.l In combination, a cartridge having a chamber from which a materialbreaking chargeof compressed gas is to bereleased, lateral gas charge release ports, andY a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the releaseof the gas charge, from said releasel chamber to the release ports and being exposed to the pressure of the gas in said, Control and release chambers, with a` greater effective surface areaiexposed( to saidlcontrol chamber than said releasenchamber, meansA for equalizing the gas pressuresV inftlae.V release and. control chambers, resilient means urging said valve into its closedposition, and venting,V means for automatically releasing the gas from saidcontrol chamber tol-cause the gas inf-the release chamber toi openthe valve when the pressure inv saidA chambers reaches a predetermined value, said venting means comprisingan elongated strip of rupturable material, plug, means threadedly mounted on said cartridge for engaging aportion of `oneface ofsaid strip outwardlyof said controlychamber, plunger means mounted for movementin said controlschamber for engaging the oppositek face of said4 strip toclamp the strip againstvthe plugwith a limited portion of the strip exposed to the pressure in said control .chamber so as to be sheared by said pressure whensaidfpredetermined value is reached, and resilient means urging said plunger means into clamping engagementwith the` strip, said plunger means being subject to the pressure innsaidcontrol chamber-to vary the clamping force on said strip, said'plug means being adjustable .away from and .toward said plungernmeans to release and reclamp the ruptured strip so the latter may be moved to successively expose unshearedrlimited pore tions to the control chamber pressure to condition the venting means for repeated operations of the-cartridge- 6.` In combination, a-cartridge having a chamber from, which a material breaking charge of compressedgas is to.bereleased, lateral gas charge releaseports,` and a t control .chamberA arranged successively longitudinallyA of-` said cartridge, a valve for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater etective surface area exposed to said control chamber than said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the gas from said control chamber to cause the gas in the release chamber to open the valve when the pressure in said chambers reaches a predetermined value, said venting means comprising a plug threadedly connected to said cartridge, a plunger mounted in said control chamber for limited movement relative to said plug, an elongated strip of rupturable material insertable between said plug and said plunger with a limited portion of the strip exposed to and to be -sheared by the pressure in said control chamber to eiect said automatic release of the gas from the control chamber when said predetermined value is reached, resilient means urging said plunger toward said plug to initially clamp the strip therebetween, said plunger having means responsive to the pressure in said control chamber for increasing the clamping action of said plunger as the pressure in the control chamber is increased to its predetermined value, said plug being adjustable away from and toward said plunger to release and reclamp said strip so that the latter may be moved to successively expose unsheared limited portions to the control chamberv pressure to condition the venting means for repeated operations of the cartridge.

7. In combination, a cartridge having a chamber from which a material breaking charge of compressed gas is to be released, lateral gas charge release ports, and a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than to said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the gas from said control chamber to cause the gas in the release chamber to open the valve when the pressure in said chambers reaches a predetermined value, said venting means comprising a plug connected to said cartridge and having a passageway therethrough, a plunger mounted in said control chamber for limited movement relative to said plug and having a passageway therethrough in alinement with the passageway through said plug, an elongated strip of rupturable material insertable between the adjacent ends of the alined passageways in said plug and plunger, the portion of said strip between said passageways being sheared by the pressure in said control chamber to effect said automatic release of the gas from the control chamber when said predetermined value is reached, means for moving said plunger toward said plug to clamp the strip therebetween, and means for adjusting said plug away from and toward said plunger to release and reclamp the strip so the latter may be moved to successively position unsheared portions between the adjacent ends of said passageways to condition the venting means for repeated operations of the cartridge.

8. In combination, a cartridge having a chamber from which a material breaking charge of compressed gas is to be released, lateral gas charge release ports, and a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than to said release chamber, means for equalizing the gas pressures in the release and control chambers, and venting means for automatically releasing the gas'from said control chamber to cause the gas in the release chamber to open the valve when the pressure in said chambers reaches a predetermined value, said venting means comprising a plug connected to said cartridge and having a passageway therethrough, a plunger mounted in said control chamber for limited movement relative to said plug and having a passageway therethrough in alinement with the passageway through the plug, an elongated strip of rupturable material insertable between the adjacent ends of the alined passageways in said plug and plunger, the portion of said strip between said passageways being sheared by the pressure in said control chamber to eiect automatic release of the gas from the control chamber when said predetermined value is reached, resilient means urging the aforesaid valve toward its closed position and urging said plunger toward said plug to clamp the strip therebetween, said plunger having a piston portion acted on by the pressure in said control chamber for increasing the clamping force exerted by said plunger as the pressure in the control chamber increases, and means for adjusting said plugaway from and toward said plunger to release and reclamp the strip so the latter may be moved to successively position unsheared portions between the adjacent ends of said passageways to condition the venting means for repeated operationsof the cartridge.

9. `In combination, a cartridge having a chamber from which a material breaking charge of compressed gas is to be released, lateral gas charge release ports, and a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the release of the gas charge from` said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the gas from said control chamber to cause the gas in the release chamber to open the valve when the pressure in said chambers reaches a predetermined value, said venting means comprising a plug threadedly mounted on said cartridge and having a passageway therethrough, a plunger mounted in said control chamber for limited movement toward and away from said plug and having a passageway therethrough in alinement with the passageway through said plug, and an elongated strip of material positioned between said plug and plunger across the alined passageways, the portion of said strip across said passageways being rupturable by the pressure in said control chamber to effect said automatic release of the gas from the control chamber when said predetermined Value is reached, said resilient means urging said plunger toward said plug to clamp the strip therebetween, and said plug being manually movable away from said plunger to release the ruptured strip for movement to place a diterent longitudinally spaced portion of the latter across said passageways during each succeeding operation of the cartridge.

10. ln combination, a cartridge having a chamber from which a material breaking charge of compressed gas is to be released, lateral gas charge release ports, and a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the release of the gas charge from said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than said release chamber, means for equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the gas from said control chamber to cause the gas in the release chamber to open the valve when the pressure in said chambers reaches a predetermined value, said venting means comprising a plug threadedly mounted on said cartridge and having an axially located 1S passageway therein, said' plug alsohavingf radially directed passageways between said axially-located passageway andits threaded surface, a'k plungerV mounted in saidV control chamber for limited movementtoward and away from said plug and having a passageway therethrough in alinement with the axiallylocated passageway in said plug, and an elongated strip of material` positioned betweensaid plug andplunger across the alined passageways, v

the portion of said strip across said passagewaysfbeing rupturable by the pressure-in said control chamber to effect said automatic release of the gas from the control chamber when said predetermined value is reached, flow of gas through the alined passageways'etfecting a limited flow of gas through said radial passageways to re ll. ln combination, a cartridge-body having arrangedV successively longitudinally thereof in the order named av chamber in which amaterial breaking(l cli-arge Ofcom-V pressed gas is to be developed and from which Ithe charge is to be released, lateral gasl charge releaseports, anda control? chamber, valve means positioned; ingthecartridge body between the release chamberV and thecontrol-charnber and havingl a greater effective surface area exposed to said control chamber-A pressure than-to said'release chamber` pressure, resilient meansnonnally urging-- the valve means toward-a position toseal the release-portsVv from the release chamber,- meansffor-'passingA gasifrom saidrelease chamber Vto said control chambertoequalize at a retarded rate the gaspressure in the control chamberI with the gas pressure in the-release chamber as" the charge is developedin'the latter chamber, andlmeans responsive solely to an increase in the gas pressurein the control chamber to a predetermined value for vlowering thegas pressure in said control chamberata greater rateA Y thansaidretarded rate to reduce the control chamber pressure to a value-substantially below'that of the gas inthe release chamber and-to causethe gas pressurein the release chamber-to move-the'valve'intol a position to` unseal the release ports. v A y,

l2. VIn combination, a cartridge body.V havingparranged successively longitudinally thereof in the order named a chamberl in which a material breaking charge of compressed gasistobe developed andfrom which the charge is to be released, lateral gas charge release ports, anda control chamber, valve'means positioned'in the cartridge. body between thereleasel chamber and the control chamberand having a greater effective surface area exposedl to said control chamber pressureV thanY to said release chamber pressure, resilient'means normally urgingV the valve means toward a positiongto seal the releaseports from the release chamber, means for equalizing at a retarded rate the gaspressure inthe control chamber with the gas pressure in the release-chamber aspthe charge is y developed in thelatter chamber, and means. responsive solely to anincrease in the gas` pressure in the control. chamber to a predetermined value for quickly lowering s the gas pressure in said controlchamber substantially below the gas pressure in therelease chamber to cause the gas pressure in the release chamber-to move the valve into a position toV unseal thefrelease ports, saidpressure lowering means comprising-means for providing a venting passageway from the control chamber -to the exterior of. the cartridge body, and a rupturable member closing -said passageway and shearedby the gas pressurel in the control chamber when ther latterlreaches saidpredetermined value.k i

13. In combination, a cartridge, body' having arranged chamber in: which amaterial breaking 4chargev of com- 16 pressed gas isl to-be developed and from which the charge is to be released, lateralv gas charge releaseports, and acontrol chamber, valve means positioned in the cartridge body'betweentherelease chamber andthe control chamber and havinga greater effective surface area exposed` to` saidl'control chamber pressure than to said release` chamber pressure., resilient means normally urging theV va-lve1A meansl toward a position -to seal the' release ports from therelease chamber, means for equalizing at a retardedrate'the gas pressure in the control chamber with the gas pressure in the release chamber as the charge is'developedinthe latter,A chamber, and means for quickly lowering the gas pressure ih said control chamber sub` sta-ntiallybelow the gas pressure in the release chamberwhenIthe pressure in the control chamber reaches apredetermined-value to' causev the gas pressure in the release chamberl to movethe'valve into a position to unseal the releaseuports, said pressure loweringV means comprising relatively'adjustable clamping members providing a passageway from the control chamber to the exterior of the cartridge body,.and a strip of rupturable material held ina position bythe clamping members so as to have'a 'limited'portion of its length1closing said passageway to bezsheared by the gas pressure in the control chamber whenthe latter reaches said predetermined value, said clampingzmernbers` being adjusted relative to each othervr torelease;andireclamp,the strip so thatthe latter' may bemoved: to successively position'v other unsheared portionsf'ofiits length to close said passageway to condition` the 'cartridge for, repeated operations.

14. In combination, a cartridgebody having arranged control-chamber, valve, means positionedin the cartridge body between the release chamber and thecontrolcham berzandV having ay greater eifectivesurface area exposedv to said. control chamber pressure than to said release cham'- ber4 pressure,l resilient means normally urging the valveH means toward a position to seal the release ports fromv therelease chambengmeans Afor'equalizring at a retarded rate the gas pressurein the control ,chamber with thel gas pressure inthe-release chamber as the chargeris developed in ,-thelatter chamber, and meansifor'quickly lowering thegas pressureA in saidl controla chamberY substantially below the gas pressure in the release chamber when'thepressure inthe control chamber reaches a predetermined value-'tocause the gas pressure in the release chamber to` move'A the valve into a position toiunseal the releaseV ports, said'. pressurelowering meansrcomprisin'g a rst clamping member movably positioned in the'controlA chamber; to be subjectedv to.th'e gas pressure therein, al

second7 clamping. member Athreadedly connected toy the cartridge b'odyl atl the outer; end of :the controlchamber sod as'to cooperate Withfthe first clamping member, said clamping'. members providing a passageway from the control chamber to theexteriorof the cartridge body, and 'a strip lof rupturable materialheld in position by the clampingrnembers sof as to havea limited portion of its length closing said passageway to be` sheared bythe gas pressure in thecontrol `chamber when the latter reaches said-predetermined'.value, said second clampingmember being threadedly. adjustedv relative to the first-clamping memberntoV release and reclamppthe strip so that the ylatter maybe. movedlto Vsuccessively position other unsheared portions of-.its length. tovclosesarid passageway, to condition -the cartridge for repeated operations.

15. Avcartrid'ge as ,defnedin claim 11 further characte'riz'edVV by thefcontrol chamberhavinga pilot valve movably mounted therein. for dividingthe chamber into inner and. outer sections,A and having a greater effective surface area'rexposed to the outer. chamber section pressure' than" to'v the inner chamber" section pressure, said innerA sectionA having'a'lateral gasV venting port, and re'- avec-,see

I7 siiient means in the control' chamberY normally holding; the pilot'valve in the' position to seal thegven't'port from` the inner control chamber section.

I6; A cartridge as defined in claim 12 further characterized by a pilot valve movably mountedin the control chamber to divide the chamberinto inner` and outer sections and havingv a` greater effective surfaceV area exposedI to the outer chamber section pressure than to the inner chamber section pressure, said inner section' having alateral gas venting port, and resilient# means in the control chamber normally holding the pilot'valve in the positionl to seal the vent port from the controlV chamber' section, said pilot valve being'moved into a` position to unseal the vent port by the gas pressure-in theeinnercontrol chamber after said rupturable member is sheared'.

17. A cartridge as defined inv claimv 13 further characterized by means carried by saidcartridge for storing' the unsheared portion of the rupturable strip prior to being moved into position between the clampingmembers and for receiving the sheared'portion of said" stripafter being moved past said position.

18. In combination, a cartridge body' having arranged4` successivelylongitudinally thereofJ inthe order named@ a chamber inwhich a material breaking' charge of compressed gas is to be developed and from which the-chargeis to be released, lateral gas chargerelease ports; andfa. control. chamber receiving compressed gas from therelease' chamber atv a rate whichwill maintain the pressure'in the control and release chambers substantially equal during-y development of said charge in the releasev chamber, val've` means positioned in thel cartridge body between the-re leasecharnber and the control chamber for sealing therelease ports, and means responsive solely toan-increase-i`n` thegas :pressure inthe control chamber to a=-pred`etermi1edvalue'- for lowering. the gas pressure in said control chamber-at a greater rate than the aforesaid rate at whichth'econtrol chamber receives gas from theV release chamber.` to reducel the control chamber pressure to a value substantially below that= of! the gas in the release chamber and' to cause the gas pressure inthel releasez chamberl to move thevalvei'ntoalposition to unseal theireleasefports.V

119. Discharge mechanism for acompressed'l gas ma-A terialE breaking cartridge, comprisingr a-v tubular discharge' section havingv one end portion to-be detachably'connect'ed? to a cartridge body and laterali discharge portsAA adjacent. said: end portiom means forming a valve seatinsaidl end portion, valve rneansmovablyv positionedi in the; discharge section, resilient means normally: urgingthe valvelmeans toward the valve seat toseal the release-ports, a cap connected tothe remaining endfportionaoffthedischarge: sec, tion and forming. a controlk chamber inl the section be tween the valvemeansaand'saidcap, andmeansI carried' by' the cap and responsive solely to an increase: in the gas. pressure in `the control chamber to a: predetermined-.value1 for venting the control chamber.

Discharge mechanism for a compressed gascmai terial breaking cartridge, comprising a tubular discharge section having one end portion to bedetachably connected?. to aV cartridge body and lateral discharge ports1adjacent; said end portion, meansrforming avalve. seatin. saidJend portion, valve meansmovably positioned inthe; discharge section, resilient meansv normallyurging the valvemeansg toward the valve seat. to.seal the; release. ports, acap'conf nected to the remaining.r end; portion of the; discharge-sec.- tion and formingacontrol chamber in thefsectionbetween'. the. valveV means; andA saidv cap., and. means. carried byf the.: cap and responsive. solely toV an increase. inthe gas. pres-1Y sure in the control chamberA to. a predeterminedvaluelfori venting the controlchamber., sadcontrol chamber venting.V means comprisingmeans for providing a-.venting passageway: for the. control chamber, and a: rupturable. member.. closing said passageway andA shearedby the. gas; pressure` in'- the control chamber whenthe, latter reaches. saiclpre-- determinedV value;

2l. Discharge mechanism for a compressed gas ma- 128 terial breaking cartridge, comprising'a tubular discharge sectionhaving oneY end portion to be detachably connectedito a cartridge body and lateral discharge ports adjacentl said' end portion, means forming a valve seat in said end portion, valve means movably positioned in the discharge section, resilient means normally urging the valve-means-toward the valve seat to seal the release ports, a cap connected to the remaining end portion of the discharge section and forming a control chamber in thesecti'on between the valve means and said cap, and means carried by the capfor venting the control chamber when: the gas pressure in said chamber reaches a predetermined: value,l said controlV chamber venting means comprisingrelatively adjustable clamping members providing a vent-A ing passageway for the control chamber, and a strip ofY` rupturablematerial heldin position bythe clamping members-so as to have a limitedvportion of its length closing said passageway-tube sheared by the gas. pressure in thev control chamber when` the latter reaches said predem termihed value, said clamping members being adjusted: rela-tive toleach other to release and reclamp the strip so thatthelatter may be moved to successively position otherV unsheared portions of its length. to close said passageway: to condition the discharge mechanism for repeated'. operations.

22. Discharge mechanism for a compressed gas. ma.- terial breaking cartridge, comprisingy a tubular discharge: sectionhavinglone end portion to bezdetachablyconnected. to acartrid'ge body, and lateral'. discharge portsl adjacent saidy end portion, means forming. avalvef. seating said' endf portion, valvemeans movably.- positioned inrthe: discharge; section; resilient: means'. normallyA urging: the: valve. means; toward: the valve seat to seal, therlele'ase ports', a cap. connected tothezremainingend portiona ofthe. discharge section and forming a control chamber in., thek sectiony be. tweenthe. valve means andsaid; cap., and means. carried?. bythe' capfor. venting the control chamber when. the gas` pressure ire said. chamber reaches. a predetermined value, said4 control. chamber venting means. comprising-` a irst. clamping; member movably positioned in the. control chamben'to be subjectedy to the gas pressure therein, a secondiclamping member threadedly connected to the: cap to. coopenate. with thezrstclam'ping member, said; clamp.- ing-membersprovidinga venting passageway'for-the con-y trolzchamber., and. aI stripv ofA rupturable material held.4 inpositioniby theclamping. members so as to'have. alimitedf. portion of? its length closingL said passageway tobesheared byrthe.4 gasgpressure in the control chamber. whenvthe-.latter reaches; saidc predetermined value,v said. second clamping member being threadedly adjusted relative to the. first clamping! member to'release and reclamp the stripso thatv the latter. maybe moved to successively position other unshearedportions of its length to` close-said passageway to` condition the discharge mechanism for repeated; operationsf.. f

23;-.. Im combination, a cartridge having a chamber from. which at material breaking, charge of compressed gas is to; be; released on thel rupture of a rupturable member,

. lateral gas charge, release ports, and a control. chamber( arranged successively longitudinallyy of said cartridge, a valvefor. controlling the release of the gas charge from saidz gas.; release,` chamber to the release ports and being exposedto the pressure of the gas in said control andrelease; chambers with a greater effective surface. area eX- posedA to said control chamber than to said. release cham.- ber;A means for equalizing the gas pressures. in the release: and control chambers, resilient meansv urging said valvey into its closed position, and venting means for. automatically releasing the gas from. said control chamf ber tofcausethe gas in the release chamber to. open the. valve. when the pressure in said chambersV reaches a.

predetermined value, said venting means` comprising means'` for clamping said rupturable member in said cartridge to. exposeY a limited. portion. thereof to the pressure of' the gas in said controlY chamber to cause said portion to be ruptured by the control chamber pressure when said predetermined value is reached, said clamping means comprising one part that is subject to the control chamber pressure so as to vary the clamping force applied to said rupturable member substantially in proportion to said pressure and a second part manually adjustable in said cartridge to clamp said rupturable member between said parts.

24. Discharge mechanism for a compressed gas material breaking cartridge the release of which gas is effected by the rupture of a rupturable member, said cartridge comprising a tubular discharge section having one end portion to be detachably connected to a cartridge body and'lateral discharge ports adjacent said end portion, means. forming a valve seat in said end portion, valve means movably positioned yin the discharge section, resilient means-normally urging the valve means toward the valve seat to seal the release ports, a cap connected to the remaining end portion of the discharge section and'forming a control chamber in the section between the valve means and said cap, and meansfcarried by the cap for venting the control chamber when the gas pressure in said chamber reaches a predetermined value, said control chamber venting means comprising relatively adjustable clamping members` providing a venting passageway for the control chamber and adapted to be positioned on opposite sides of said rupturable member and to have sealing engagement therewith.

25. In combination, a cartridge having a chamber from which a material breaking'charge of compressed gas is to be released on the rupture of a rupturable member, lateral gas charge release ports, and a control chamber arranged successively longitudinally of said cartridge, a valve for controlling the release of the gas charge from 4'said gas release chamber to the release ports and being exposed to the pressure of the gas in said control and release chambers with a greater effective surface area exposed to said control chamber than to said release chamber,means lfor equalizing the gas pressures in the release and control chambers, resilient means urging said valve into its closed position, and venting means for automatically releasing the -gas from said control chamber to cause the gas in the release chamber to open the valve when the pressure in saidchambers reaches' a predetermined value, said' venting means comprising way therethrough to the exterior of the cartridge body and being disposed on opposite sides of said rupturable member so that a restricted portion thereof closes said passageway and one side thereof is in direct contact with said gas, said second clamping member being secured-to said cartridge body and reactingV against the other side of said rupturable member to cooperate with said first clamping member and provide a preliminary sealjwith said rupturable member, saidrtirst clamping member being movably positioned in said cartridge body and subjected to the gas therein to increase-the clamping force applied to said rupturable member in' proportion to said pressure Vand provide the final Seal with said rupturable member. Y

26. In a compressed gas chamber the discharge of which is controlled by a shear element, the improvement which comprises means forming a passageway to be closed by said shear element, said passageway forming means comprising an inner member having one portion of said passageway therewithin and an outer member' in end-to-end alignment with said inner member axially of theV chamber and having 'another portionof'said passage" way therewithin as an endwise continuation'of said oneber and exposed to and movable outwardly by the pressure of the gas in the chamber to vary the sealing forces` applied tothe shearl element by the inner and outer members substantially in proportion to said gas pres-4 sure to clamp and seal said shear elementVV therebetween in a inal clamping and sealing relationship` so that the shear element may be easily removed and replaced after the chamber has been discharged, said inner member being movable toward said outer member no further than required to effect said clamping and sealing relationship, means within said chamber limiting the inward movement of said inner member to provide said preliminary seal, and therportion ofsaid shear element closing said passageway being sheared from the Yremainderof the element to effect automatic release of gas through, said passageway when the pressure of the gas is increasedto a determined value.

27. In a compressed gas chamber the'discharge of which is controlled by a shear element, the improvement which comprises means forming a passageway to be closed by said shear element, said passageway forming means comprising an inner member and an outer member Vin endwise axially spaced relation thereto, said outer member being adjustably carried by the chamber, the passageway within one member continuing axially endwise into the other member, `said members being movable endwiserelatively toward each other and having opposed metallic surfaces surrounding said passageway forj clamping and sealing said shear element therebetween in arpreliminary closing and sealing relationship with the passageway, said inner member being separate and; distinct from said chamber and exposed to and movable outwardly by the pressure of the gas in the chamber to vary the sealing forces applied to the shear elementbysaid clamping surfaces substantially in proportion to said gas pressure to clamp and seal said shear element therebetween in a nal clamping and sealing relationship so that the shear element may be easily removed and replaced after the chamber has been discharged, means within said chamber limiting the inward movement of saidinner member to provide said preliminary seal andthe portion of said shear element surrounded bysaid opposed surfaces and closing said passageway'being sheared from the remainder of the irst and second clamping members providing a lpassage-V element to eiect automatic release of gas through said passageway when, the pressure of the gas is increased to a predetermined value.v

28. In a compressed gas chamber the dischargev of 3 which is controlled byY ashear element, the improvement which comprises means forming a passageway to be closed by` said shear element, said passageway forming means comprising an inner member, and an outer member carried by the chamber in axial endwise alignment for movement relative to each other to clamp and seal said shearV elementtherebetween in a'preliminary closing and sealing relationship withV the passageway, there being one portion of said passageway within said inner member on one side of said shear element and another portion of said passageway constituting an endwise continuation of said one portion on'the other side of said shear element within said' outer member,- saidV inner member being disposed wholly on the side of said shear element to which the gas pressure is applied and being separate and distinct from said chamber and exposed to and movable outportion, said outer member being adjustably carried by wardly by the pressure of the gas in said chamber and Y having a. peripheral seal to prevent the flow of gas between adjacent surfaces ofthe chamber and the inner member into direct contact with the shear element, variations in the pressure of the gas in the chamber etecting substantially proportional variations in the sealing forces applied tothe shearelement by said inner and outer members to clamp and seal said shear element therebetween in a final clamping and sealing relationship so that the erregend shear element may be easily removedI from between said members afterthe chamber has been discharged, means within said chamber limiting the inward movement of said inner member to; provide said preliminary seal, and the portion of said shear element closing said; passageway being sheared from the remainder of the element to effect automatic release of gas through the passagewayv when the pressure o 'lthe gasv isincreased` to a predeterminedA value;

29. In acompressed' gas chamber the discharge of which is controlled by a shear element, the improvement which comprises means, forming a passageway to be. closed by said shear element, said passagewayA forming means comprising an inner member and an outer member, said` outer member being adjustably carried by said chamber, saidI inner member being separate and distinct from and mounted inl said chamber and guided by the chamberfor outward movementv toward said outer member by an increase in the gas pressure: in said4 chamber, means forming a seal between surface portions: of said inner member and chamber,` and said outer member-being adjustable into and out of clamping-relationship` with said inner member to clamp the shear element, therebetween in a preliminary closing and sealing, relationship; with the passageway and to release ythe shear element sothat the latter may be removed and replaced to condition the chamber for repeated operations, variations in the gas pressure iny said chamber effectingf substantially proportional variations. inV theV clamping forces:.applied to. said shear element by the inner and outer members to clamp and seal said shear element therebetween in a final clamping and sealing relationship so that the shear element is rigidly clamped to seal the passageway when the gas pressure in the chamber is increased and is loosely clamped to permit the aforesaid adjustment of the outer member to release the shear element after the chamber has been discharged, there being at least one transverse opening in the wall of said chamber in register with the portions of said inner and outer members between which said shear element is clamped for receiving said shear element and facilitating the removal of the remnant thereof after shearing of said element and discharging of the compressed gas, and means within said chamber limiting the inward movement of said inner member to provide said preliminary seal, the portion of said shear element closing said passageway being sheared from the remainder of the element to eiect automatic release of gas through the passageway when the pressure of the gas is increased to a predetermined value.

30. In a compressed gas chamber the discharge of which is controlled by a shear element, the improvement which comprises means forming a passageway -to be closed by said shear element, said passageway forming means comprising an inner member and an outer member having alined portions of said passageway formed therein, said outer member being threadedly mounted on said chamber, said inner member being separate and distinct from and slidably mounted in said chamber for limited movement relative to said outer member to clamp and seal said shear element therebetween in a preliminary closing and sealing relationship with said passageway, and resilient means urging said inner member toward said outer member for loosely clamping the shear element therebetween when said outer member is threaded into clamping relationship with said inner member to provide said preliminary seal, said inner member being subject to the gas pressure in said chamber to increase the clamping force on said shear element substantially in proportion to increases in said gas pressure and to tightly seal said shear element between said inner and outer members in a nal clamping and sealing relationship, and said outer member being adjustable away from and toward said inner member to permit the shear element to be removed and replaced when the portion of the element closing said passageway has been sheared from the remainder of the 22 element byl an; increase inthe' gas pressurein the` chamber" to a predetermined value; toA effectl automatic' release of: gas through said passageway. y

31. In a compressed gas: chamber the discharge ofi which is controlled by a replaceablerupturable e1ement aV body having a; chamber` for receiving av charge ofi highly compressed gas; means forl clampingv said rupturable element` in sealingposition in said body against the` pressure exertedl by saidl gas comprising irst andL second? clamping membersY providing a passageway; extending' therethrough to the exterior ofY the*- body, each of` said, members being'wholly disposed ou opposite sides respectively of said rupturable elementV so that the central" portion of' saidl element closes saidpassageway' and onetside ofA said element isl indirect contact'withl said gas,l said second clamping member' reacting against the' other sideKV of said rupturable elementto cooperate withA said iirst clamping member. and" provide a preliminary sealL with said rupturable element; said iirst clamping, member being separate. and distinct from and movable relative to1saidl body andsubject to outward movement'bythe gas therein toA increase theclampingj force applied tn` said rupturable' element in proportion tosaid" pressure; and provide the fnal seal with said rupturable element; and means in said bodyV limitingJ the inward movement of'y said first clamping member to provide saidl preliminary seal.

32. In a compressed gas chamber thei discharge of which is controlled by av replaceable rupturable. element, a body having a chamber for receivinga charge of highlycompressed gas; means for clamping said rupturable element in sealing position in said body against the pressure exerted by said gas comprising first and second clamping members providing a passageway extending therethrough to the exterior of the body, said rst and second members being wholly disposed on opposite sides of said rupturable elemen-t so that the central portion of said element closes said passageway and one side of the central portion of said element is in direct contact with said gas, said second clamping member reacting against the other side of said rupturable element to cooperate with said first clamping member and provide a preliminary seal with said rupturable element, said rst clamping member being separate and distinct from and movable relative to said body and subject to outward movement by the gas therein to increase the clamping force -applied to said rupturable element in proportion to said pressure and provide the iinal seal with said rupturable element, and peripheral sealing means between the inner surface of said body and the outer surface of said first clamping member to prevent the escape of gas between said surfaces into direct contact with the rupturable element; and means in said body limiting the inward movement of said rst clamping member to provide said preliminary seal.

33. In a compressed gas chamber the discharge of which is controlled by a replaceable rupturable element, a body having a chamber for receiving a charge of highly compressed gas; means for clamping said rupturable element in sealing position in said body against the pressure exerted by said gas comprising first `and second clamping members providing a passageway therethrough to the exterior of the body, said clamping members having alined portions of said passageway formed therein and being disposed on opposite sides of said rupturable element so that a restricted portion thereof closes said passageway and a substantial portion of one side thereof is in direct contact with said gas, said second clamping member being secured to said body and reacting against the other side of said rupturable element to cooperate with said irst clamping member and provide a preliminary seal with said rupturable element, said first clamping member being disposed wholly on the side of said rupturable element to which the gas pressure is applied and being separate and distinct from and movable relative to said body and subject to outward movement by the gas therein to increase the clamping force applied to said rupturable element in '23 proportion to said pressure and provide the nal seal with said rupturable element, Y' means lfor effecting screw threaded adjustment between said second clamping member and said body and being required to be screwed up only .hand tightjtoy provide the preliminary seal; there being at least one transveres opening in the Wall of said body in register with the portions of said clamping members between which said rupturable element is clamped for receiving said element and facilitatingthe removal of the remnant thereof after rupture yof 'said element and discharge of the compressed glas, and means in said body limiting the inward movement of said rst clamping member to provide said preliminary seal.

34. In a t compressed gas chamber the discharge of which is controlled by a'replaceable rupturable element, a body having av chamber for receiving a charge of highly compressed gas, means `for clamping said rupturable ele rnent in sealing position in said body against the pressure exerted by said gas comprisingrst and second clamping members Vproviding a passageway'V therethrough to the exterior of the body and being disposed on opposite sides of said rupturable element so that a restricted portion thereof closes said passageway and `one side thereofis VinY direct contact with said gas, said second clamping member being secured to said body and reacting against the other side of said rupturable element to cooperate with said first clamping member and provide a preliminary seal with said rupturable element, said first clamping member being separate and distinct from and movable -24 relative to said bodyand subjectpto outward movementv by the gas therein to increase 4the clamping `force applied to said rupturable element in proportionY tosaid pressure and provide the final seal with said rupturable element, said second clamping member havingthreadedgengagement with said body and being required to be screwed up only hand tight to provide the preliminary seal, Vthere being one or more ports placing the threads between said second clamping member and said body in` communica-` tion with'said passageway to cause a portion of the gas to discharge into said threads and prevent the accumulation of dust therein; and means in said body limiting the inward movement of said first vclamping member to providersaid 1'9relimir1 ary. lseal,

' References Cited in thel file of this patent UNITED STATES PATENTS Armstrong May 26, 1931 1,807,144 y 2,034,569 p Ferrell etal. Mar. 17,1936 2,083,735- Noble f June 15, 1937 2,207,191 Geertz 1 July 9, 1940 2,435,116 Armstrong Jan. 27, 1948 2,502,694 -Armstrongl r Apr. 4, 1950 2,591,529 Filstrup' Apr. 1, 1952 2,636,437 Loving Apr. 28, y1953 FOREIGN PATENTSV Y 259,799 Great Britain Oct. 21, 1926 313,333Y Great Britain June 13, 1929