US2720170A

US2720170A - Material breaking cartridge

Info

Publication number: US2720170A
Application number: US290604A
Authority: US
Inventors: James C Hesson; John L Smith; James A Swanson
Original assignee: Cardox Corp
Current assignee: Cardox Corp
Priority date: 1952-05-28
Filing date: 1952-05-28
Publication date: 1955-10-11
Anticipated expiration: 1972-10-11

Description

Oct. 11, 1955 J. c. HEssoN Erm.

MATERIAL BREAKING CARTRIDGE 2 Sheets-Sheet l Filed May 28, 1952 2 Sheets-Sheet 2 Oct. 11, 1955 J. c. Hx-:ssoN EVAL MATERIAL BREAKING CARTRIDGE Filed May 28, 1952 doh/7 (Sm/'tk and James ,4. Swanson BY%.KMW rraRA/Ev nited States Patent Oiiice ZQZQT Patented Oct. 11, 1955 2,720,170 MATERIAL BREAKING CARTRIDGE James C. Hesson, Riverdale, and .lohn L. Smith and James A. .Swanson Chicago, Ill., assignors to Cardox Corporation, Chicago, lll., a corporation of Illinois Application May 28, 1952, Serial No. 290,604

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 release of the gas being controlled by a quick acting, full opening valve.

Cartridges employing a highly compressed charge of air or other gases for breaking down coal in mines, and for other similar operations, are well-known and have been widely used in recent years. Such cartridges may be precharged with a highly compressed liqueied gas or with a solid which will produce a highly compressed gas when heated or burned. They, also, may be charged with a highly compressed gas after they are properly positioned relative to the material to be broken down. Regardless of the time or manner in which the cartridge receives its gas charge, however, it is of primary importance that the charge be quickly and completely released upon operation of the cartridge, and that the cartridge may be easily and rapidly reconditioned after each operation.

Each of the cartridges of the above mentioned types, because of the necessity for the operator, or shot tirer,

. to be located -at a safe distance when a cartridge is discharged, has been provided with a charge release mechanism which will operate automatically, as distinguished from manually, upon the attainment of a cert-ain pressure condition within the cartridge. However, thecause for and/ or the condition which brings about the attainment of the certain pressure condition within the dilerent types of cartridges has varied to such an extent that some are considered as being automatically operated while others are manually operated.

The automatically operated types of cartridges release their material breaking charge when the pressure of the gaseous charge being developed within the cartridge has increased to a given predetermined value, which is controlled by the construction or adjustment of the release mechanism. The manually operated types of cartridges release each material breaking charge at whatever available pressure the operator may desire.

lt will be appreciated, therefore, that the basic dilerence between the automatically and manually operated types of cartridges is that the operator, or shot rer, is unable to exercise any control over, or cannot change, the pressure at which the material breaking charge is released from an automatically operated cartridge, while the operator is able to exercise complete control over, and 'can change at will, the pressure at which each material breaking charge is released from a manually operated cartridge.

Whether automatically or manually operated cartridges are employed for a given coal mining operation usually will depend on such factors as the character of the coal to be mined, the skill of the shot firers employed, and the opinions or desires of the mine owner or superintendent.

Due to variations in the characteristics of the coal encountered in different portions of some mines, the maximum etliciency of operation can only be obtained if both automatically and manually operated cartridges lare employed. The cartridges that have been available on the open market heretofore have been either of the automatic type or of the manual type. Therefore, the owners of such mines have been compelled either to acquire and maintain both types of cartridges or to accept the reduced efficiency of operation that will be obtained when only one of the two types of cartridges is employed.

It is the primary object of this invention to provide a compressed gas material breaking cartridge which can be very easily and inexpensively converted from an automatically operated cartridge to a manually operated cartridge, and vice versa.

A further important object of the invention is to provide a compressed gas material breaking cartridge which may be employed as a manually operated cartridge, that will release each material breaking charge at whatever pressure the operator may desire, but which will become an automatically operated cartridge, that Will release its material breaking charge when the pressure thereof has increased to a given predetermined value, if the operator has not elected to eiiect release of the charge at a lower pressure value.

Still another important object of the invention is to provide a compressed gas material breaking cartridge which may be caused to function either as an automatically operated cartridge or as a manually operated cartridge by using certain interchangeable elements in the charge release mechanism.

Another important object of this invention is to provide a compressed gas material breaking cartridge having an automatic charge release mechanism, located entirely in the discharge end of the cartridge, the operation of which is effected by controlling the increase of the gas pressure on one portion of the release mechanism relative to the increase in the pressure of the charge of gas being developed in the cartridge.

A further important object of the invention is to provide a compressed gas material breaking cartridge having an automatic charge release mechanism which may be quickly and easily modied to cause it to effect said release either when the pressure of the gaseous charge has been increased to a predetermined value or when the increasing of the pressure of the gaseous charge has been stopped.

Another important object of the invention is to provide a compressed gas material breaking cartridge having an automatic charge release mechanism, the operation of which is controlled by increasing the gas pressure on one portion of the release mechanism in a predetermined relationship with the increase of the pressure of the charge being developed in the cartridge, said predetermined relationship being quickly and easily modied to effect said release either when the pressure of said gaseous charge has been increased to a predetermined value or when the increasing of the pressure of the charge has been stopped.

A still further object of the invention is to provide a compressed gas material breaking cartridge having an automatic release valve mechanism, located entirely in the discharge end of the cartridge, which will operate to quickly and completely release the material breaking charge when the controlled iiow of gas from the main charge receiving chamber of the cartridge to one portion of the release mechanism has increased the pressure in the latter to a value at which it will eiect movement of a piston mounted in said portion of the release mechanism.

A more specific object of the invention is to provide a compressed gas material breaking cartridge having an automatic charge release mechanism which includes a plurality of sequentially operating valves, the actuations of which are initiated by the controlled application of gas pressure to one valve in a predetermined relationship with the pressure of the gaseous charge being developed in the cartridge, whereby the direction of the initial diierential in the opposed forces acting to close said valve is reversed and the valve is quickly moved into its open position.

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

In the accompanying draw-ings forming a part of this specification and in which like reference characters are employed lto designate like parts .throughout the same,

Figure 1 is a longitudinal sectional view of a material breaking cartridge `embod-ying ythe invention,

Figure 2 is a transverse sectional view taken on ine 2 2 .of Fig. 1,

Figure 3 is a transverse sectional view taken on line 3-3 of Fig. l,

Figure 4 is a longitudinal sectional View of a modiiied form of material breaking cartridge, and

Figure 5 is a longitudinal sectional view of a still further modified form of material breaking cartridge.

In the drawings, wherein for the purpose of illustration are shown the preferred embodiments of the invention, and first particularly referring to Figs. l to 3, inclusive, the reference character 6 designates a cartridge body having a compressed gas .charge receiving chamber e 7. One end of the cartridge body 6 is provided with .an internally threaded aperture 8 for connection with a length of tubing 9, or the like, through which a charge of compressed air, or other gas, is introduced into the chamber 7.

The tubing 9 comprises only one of several well-known methods of providing a charge of compressed gas in the chamber 7, and it is to be understood that the invention is not to be limited to the particular means disclosed. It is contemplated that the invention, also, may be used with equal efficiency when the charge of compressed gas is introduced into the chamber 7 `as a lique'lied gas or decomposable solid.

The end portion of the body member 6 opposite the aperture 8 is internally threaded at 11 for connection with an adapter member 12. Sealing between the opposed surfaces vof the cartridge body 6 and the adapter member 12 is provided by the O-ring 13 which is seated in the groove 14 at the inner end portion of the adapter member. The central portion of the adapter member 12 is provided with two or more indentations 15 in its outer surface for cooperation with a Spanner wrench which may be used in assembling and disassembling the threadcdly connected parts. The outer end portion of the ladapter member 12 is externally threaded at 16 and is formed with an end edge which functions as an annular valve seat 17.

A discharge section 18 is internally threaded at its inner end portion 19 for connection with the outer end of the adapter 12 and is provided with a circumferentially alined row of discharge or release ports 20 which are positioned closely adjacent the valve seat 17 and are of sutiicient number and total cross-sectional area to effect rapid release of the gas from the cartridge chamber 7. The discharge section 18 is .of tubular construction and has an inner diameter that is slightly greater than that of the annular valve seat 17.

A piston type main valve 21 is positioned in the dircharge section 18 for longitudinal movement between its seated and fully open positions. The valve 21 is of hollow cylindrical construction and has an open inner end and a substantially closed outer end with a centrally located passageway 22 therethrough. The open inner end of the valve is beveled at its periphery to provide a seating surface 23 for engagement with the valve seat 17. The closed outer end portion of the valve 21 has an O-ring 24 positioned in the circumferential groove 25 to provide a seal between the valve and the inner surface of the discharge section 18. The valve 21, therefore, at

all times seals the discharge ports 20 from the interior of the discharge section 18 and, when the valve is in its closed position, seals the discharge ports 2t) from the charge release chamber 7.

Positioned in the opposite end of the discharge section 18 from the main valve 21 is a pilot valve support Cil 26 having a radially outwardly extending ange 27 which is rigidly clamped against the annular end .surface 28 of` the discharge section by an end cap 29 which is threadedly connected to the outer end portion of the discharge section. Sealing is provided between the pilot valve support 26 and the inner surface of the discharge section 18 by an O-ring 30 which is seated in the groove 31 adjacent the radial iange 27. Positioned between the main valve 21 and the support 26 is a spring 32 having its opposite end portions seated against radial surfaces 33 and 34 of the valve 21 and support 26, respectively, to urge the valve 21 toward its seat 17. Formed within the discharge section 18 between the main valve 21 and the support 26 is a main control chamber 35.

The annular portion of the pilot valve support 26 which `extends axially inwardly from the ange 27 is internally threaded at 36 to receive a cylindrical guide member 37. The portion of the pilot valve support 26 which extends axially outwardly from the ange 27 passes through an opening 38 in the end cap 29 and is drilled to form a cylinder 39 near its middle portion. Outwardly of the cylinder 39 the support 26 is drilled at a substantially greater diameter than the cylinder and threaded to receive an end cap 40 having an inwardly opening cylindrical recess forming a pilot control chamber 41, Sealing is provided between the end cap 40 and the support 26.by an O-ring 42 seated in the groove 43 adjacent the inner end of the cap.

Inwardly of the cylinder 39 the diameter of the drilled hole in the support 26 is reduced to provide a guide collar 47, and inwardly of the guide collar the diameter is again increased to slightly less than the diameter of the cylinder 39 to form a venting passageway 48. The inner end edge of the venting passageway 48 forms an annular pilot valve seat 49 and venting ports 51 extend generally radially outwardly from the Venting passageway 48 to the outer surface of the support 26, as illustrated in Fig. 3. Venting passageways 52 extend between the inner end portion of the cylinder 39 and the venting passageways 51 to maintain atmospheric pressure in the inner end of the cylinder at all times.

Extending through the support 26 from its inner face to the bottom of the drilled outer end portion into which the cap 40 is threaded is a passageway 53 the outer end portion of which is enlarged and threaded to receive a plug 54 having a passageway 55 extending axially therethrough. The cross-sectional area of the passageway determines the extent to which the flow of gas through the passageway 53 from the main control chamber 35 to the pilot control chamber 41 is restricted. It will be readily apparent that plugs 54 having passageways 55 of different cross-sectional area may be interchanged to vary the extent to which the passageway 53 is restricted.

Mounted in the guide member 37 adjacent the venting passageway 48 is a pilot valve 56 having a seating surface 57 for engagement with the pilot valve seat 49. As illustrated in Fig. 2, the inner end of the pilot valve 56 is tlanged radially outwardly and is provided with circumferentially spaced, longitudinal fingers 58 for engaging the inner surface of the guide member 37 to maintain the axial alinement of the pilot valve. Apertures 59 are provided in the radially flanged portion of the pilot valve 56 for the free liow of gas from the main control chamber 35 to the venting passageway 48 when the pilot valve is in its open position.

A spring 61 is positioned in the interior of the guide member 37 and compressed between the pilot valve 56 and the annular collar 62 which is threaded into the inner end of the guide member. It will be apparent, therefore, that the force exerted by the spring 61 on the pilot valve 56 may be varied in accordance with the strength of the spring selected and, to a lesser extent, by the longitudinal position to which the collar 62 is adusted in the guide member 37. The central opening in the collar 62 and the circumferentially spaced openings 63 in the guide member 37 facilitate the flow of gas from the main control chamber 35 to the pilot valve 56.

Positioned in the cylinder 39 is a piston 64 having an operating plunger 65 extending through the guide collar 47 in sliding engagement therewith. Sealing is provided between the piston 64 and the Wall of the cylinder 39 by an O-ring 66 positioned in the groove 67 in the peripheral wall of the piston. The inner end of the operating plunger 65 is seated in the recess 68 in the outer face of the pilot valve 56. The piston is maintained in its cylinder 39 by an annular stop ring 69 at the outer end of the cylinder.

The operation of the cartridge when the compressed air, or other gas, is employed, will be described as follows:

The cartridge, in an uncharged condition but connected to a suitable source of supply of the compressed air, or other gas, by the feed line 9, 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 main or charge release chamber 7 is sealed from the discharge ports 20 by the engagement of the main valve 21 with its seat 17 and by the O-ring 24. The charge release chamber 7, however, is in communication with the main control chamber 35 through the passageway 22 in the main valve 21. The main control chamber 35 in the discharge section 18 is sealed from the venting ports 51 by the engagement of the pilot valve 56 with its seat 49. Communication between the main control chamber 3S and the pilot control chamber 41 is provided by the passageways 53 and 55 in the housing extension 26 and plug S4, respectively. Each of the valves 21 and 56 is initially moved to its seated position by the 'springs 32 and 61, respectively.

The compressed air delivered to the charge release chamber 7 will rapidly build up the pressure therein. During this charging of the chamber 7, compressed air is permitted to ow into the main control chamber 35 through the passageway 22 in the main valve 21 so that the pressures in the charge release chamber 7 and the main control chamber 35 will be maintained substantially equal. The main valve 21, therefore, will be maintained in its seated, or closed, position by the spring 32 and by the differential force acting on the opposite ends of the valve. In the Words, the eifective surface area of the valve 21 exposed to the fluid pressure in the main control chamber 35 is greater than the elfective surface u area of the valve exposed to the fluid pressure in the charge release chamber 7 so that the total forces acting upon the valve are unbalanced in the direction to maintain the valve in its closed position. The eifective surface areas on the opposite ends of the valve 21 may be considered as being equal to the cross-sectional area of the main control chamber 35 and the cross-sectional area of the valve seat 17, each minus the cross-sectional area of the passageway 22. Since the valve 21 is maintained in its closed or seated position by the differential forces acting on its opposed faces, the spring 32 is of a type which will exert a relatively light force upon the valve.

It will be readily apparent that the main valve 21 Will remain in its closed position until the pressure of the gas in the main control chamber 35 is suddenly reduced, at which time the pressure of the gas in the charge release chamber 7 will quickly move the valve into its fully open position to release the work performing charge. This sudden reduction of pressure in the main control chamber 35 is brought about by operation of the pilot valve 56, as follows:

While the compressed air is -being delivered to the charge release chamber 7 and the pressures in the charge release and main control chambers 7 and 35, respectively, are being increased, the pilot valve 56 is subj'ected to three separate forces. The first of these forces is applied by the spring 61 Which initially moves the pilot valve 56 into its closed position and which will tend to maintain the valve in its closed position. The second force to be considered is applied to the valve by the pressure of the gas in the main control chamber 35 acting over an effective surface area equal to the cross-sectional area of the pilot valve seat 49. This second force also tends to maintain the pilot valve 56 in its closed position. The third force is applied to the valve 56 by the pressure of the gas in the pilot control chamber 41 acting on the piston 64, the effective surface area of which is slightly greater than the effective surface area at the valve seat 49. This third force opposes the first and second forces and will effect opening of the pilot valve 56 when it exceeds the sum of the other two forces. From the above discussion it will be obvious that, since the pressure of the gas in the pilot control chamber 41 can never exceed that of the gas pressure in the main control chamber 35, the effective surface area of the piston 64 must exceed the eiective surface area at the valve seat 49 by an amount which, when subjected to the pressure of the gas in the pilot control chamber, will overcome the force applied to the valve by the spring 61.

Considering now the magnitude of the various forces discussed above and how their relationship may be varied to provide diierent modes of operation for the pilot valve 56, the preferred mode of operation is provided by the following relationship:

The passageway 55 is formed with a sui'icient crosssectional area to permit an increase in the pressure of the gas in the pilot control chamer 41 at a rate whereby it is maintained substantially equal to the pressure of the gas in the main control chamber 35. These two substantially equal pressures acting on the effective surface area at the valve seat 49 and an equal portion of the eiective surface area of the piston 64 will apply balanced opposed forces to the valve 56 and, therefore, may be disregarded. The only eiective forces acting on the valve 56, therefore, may be considered to be the force of the spring 61 and the opposed force applied by the pressure of the gas in the pilot control chamber 41 to that portion of the effective surface area of the piston 64 in excess of the eifective surface area at the valve seat 49. The latter of these forces Will increase in direct proportion to the increase in the substantially equal gas pressures in the charge release, main control and pilot control chambers 7, 35 and 41, respectively, to a value at which it will exceed the force applied by the spring 61 and will thereupon eifect opening of the pilot valve 56. The opening of the pilot valve 56, therefore, will occur automatically when the pressure of the gas in the charge release chamber 7 has reached a predetermined value and, since the difference in the effective surface areas of the valve is relatively small, this result may be accomplished by the proper selection and adjustment of the spring 61.

If the operation of the cartridge is to be entirely manually controlled by an operator located at a remote point from the cartridge, this can be accomplished by reducing the cross-sectional area of the passageway 55 in the plug 54 and by reducing the strength of the spring 61 to a relatively low value. With the cartridge so modified, the increase in pressure of the gas in the pilot control chamber 41 will be at a retarded rate relative to the increase in pressure of the gas in the main control chamber 35. The force applied to the valve 56 by the pressure of the gas in the main control chamber 35 acting over the effective surface area at the valve seat 49 will exceed the force applied to the piston 64 by the lower pressure of the gas in the pilot control chamber 41 for so long as the pressure in the main control chamber is being increased. When the substantially equal pressures of the air in the charge release chamber 7 and the main control chamber 35 have reached a desired work performing value, the operator, located at a remote point from the cartridge, may stop the ow of air through the feed line 9 so that there can be no further increase in the pressure of the gas in the main control chamber. The pressure of the gas in the pilot control chamber 41 will thereafter continue to increase relative to the substantially constant pressure in the main control chamber 35 until the force exerted on the piston 64 by the pressure of the gas in the pilot control chamber exceeds the forces exerted on the valve 56 by the spring 61 and by the pressure of the gas in the main control chamber 35. The valve 56 will thereupon be moved into an open position to effect release of the work performing charge. The relatively light force applied to the valve 56 by the spring 61 has little effect upon the operation of the cartridge and functions principally to seat the pilot valve prior to the introduction of the charge into the cartridge.

The two modes of operation described above are illustrative, only, and it is to be understood that they may be varied from their exact forms as described without detracting from the utility of the invention. For example, the cartridge may be made to operate at a given predetermined pressure in the charge release chamber 7 despite a limited lag in the increase of the pressure of the gas in the pilot control chamber 41 relative to the increase in the pressure in the main control chambers 35. In other words, since the effective Surface area of the piston 64 is greater than that at the valve seat 49, the force exerted by the pressure of the gas in the pilot control chamber 41 may exceed the force exerted by the pressure of the gas in the main control chamber 35 even through the latter pressure slightly exceeds the pressure in the pilot control chamber. This being true, proper selection of the spring 61, and adjustment thereof, would provide the operation of the cartridge at a predetermined pressure in the release chamber 7.

Regardless of the mode of operation of the pilot valve 56, opening of the valve will cause the gas in the main control chamber 35 to be released through the venting ports 51 at a much more rapid rate than it is possible for gas to flow through the passageway 22 in the main valve 21 and through the passageways 53 and 55 between the main control and pilot control chambers 35 and 41, respectively. Both the main valve 21 and the pilot valve 56, therefore, will. remain in their fully opened positions until substantially the entire gaseous charge in the release chamber 7 has been released through the discharge ports 20. In this connection, it will be noted that the rapid Venting. of the gas from the main control chamber through the passageways 51 relative to the ow of gas from the pilot control chamber 41 through the passageways 53 and 55, will cause the pilot valve 56 to snap into its fully opened position after a very slight movement away from its seat 49.

The modification of the invention illustrated in Fig. 4 employs a body member 6, an adapter member 12, a discharge section 1S, a main valve 21 and a spring 32 which are substantially identical to those illustrated in Figs. 1 to 3, inclusive, and the same reference characters have been applied to corresponding parts of each.

Positioned in the outer end of the discharge section 18 is a pilot valve support 74 having a radial ange 75 that is rigidly clamped against the annular end surface 28 of the discharge section by the housing extension 76 which is threadedly connected to the outer end of the discharge section. Sealing between the support 74 and the inner surface of the discharge section 18 is provided by an O-ring 77 which is seated in the groove 78 in the outer surface of the support. Extending axially through the inner portion of the support 74 is a venting passageway 79, the inner edge of which forms an annular valve seat S and the outer end p'ortion of which communicates with the radial venting passageways 81. The outer ends of the radial passageways 81 are connected by a circumferential groove S2 in radial alinement with venting' ports S 83 in the housingextension 76. The outer face of the support 74 is formed with an axially extending annular guide ange 84 and exhaust ports 85 extend through the outer end of the adapter member from the venting passageways 81 to the space between the guide flange and the housing member 76.

Extending axially inwardly from the inner face of the pilot valve support 74 is a cylindrical spring guide 86 which tits within the coils of the outer end portion of the spring 32 and is provided with a radial surface 87 against which the outer end of the spring is seated. The bore of the guide 86 is of a substantially greater diameter than the pilot valve seat so that the valve seat is in op'en communication with the main control chamber 88 formed within the discharge section 18. The main control chamber 88 is in communication with the release chamber 7 through the aperture 22 in the main control valve 21.

The housing extension 76 projects axially outwardly from the pilot valve support 74 and is provided with a bore 89 of substantially greater diameter than the outer surface of the guide flange S4. The outer end portion of the housing extension 76 is internally shouldered at 91 and a sleeve 92 is inserted into the cylindrical bore S9 and seated against the shoulder at 91. The sleeve 92 is clamped into its position in the bore 89 by the end cap 93 which is threadedly connected to the housing extension 76. Sealing is provided between the end cap 93 and the housing extension by O-ring 94 seated in the groove 95 in the outer surface of the housing extension. The inner end portion of the sleeve 92 is drilled to form a cylinder 96 in axial alinement with the pilot valve seat 80, the venting passageway 79 and the bore of the guide flange 84. The diameter of the cylinder 96 is slightly greater than that of the pilot valve seat 80. The outer end portion of the sleeve 92 is drilled to a substantially greater diameter than the cylinder 96 to form a pilot control chamber 97 between its inner end portion and the end cap 93.

A piston 98 is positioned in the cylinder 96 with its valve operating plunger 99 extending axially through the guide flange 84' in sliding engagement therewith and through the venting passageway 79 into the interior of the spring guide 86. Securely mounted on the inner end portion of the operating plunger 99 is a pilot valve 101 having a seating surface 102 for engaging the pilot valve seat 80. Sealing is provided between the piston 98 and the cylinder 96 by an O-ring 103 positioned in the groove 104 in the piston. An axially located passageway 105 extends through the entire length of the valve operating plunger 99 and piston 98 to provide communication between the main control chamber 88 and pilot control chamber 97. The outer end of the passageway 105 is of a reduced cross-sectional area at 106 to restrict the flow of gas through the passageway.

Mounted on the valve operating plunger 99 in abutting engagement with the piston 98 is a collar 107 which extends radially outwardly into frictional engagement with the cylindrical bore 89. The collar 10'/ is provided with a plurality of passageways 108 extending therethrough for the free iiow of gas from one side of the collar to the other as it isy moved longitudinally in the bore 89.

Positioned between the collar 107 and the outer face of the pilot valve support 74 are a plurality of dished ring spring members 109. These spring members 109 are arranged in two opposed stacks to form a Belleville spring. It will be appreciated that the particular arrangement of the spring members 109 may be varied to regulate the strength and deflection of the spring unit as required. Further, it is preferable that the spring members 109 be of a design which will apply a constant or decreasing spring force as they are deected within their working range. The space within which the spring inemb'e'rs 1'09l are positioned is maintained at substantially atmospheric pressureby the exhaust ports 85.

The manner in which the cartridge illustrated in Fig. 4 operates is identical to that of the cartridge illustrated in Figs. l to 3, inclusive, and will not be described in detail. The spring members 109 function in exactly the same manner as the spring 61 and the passageway 105 with its restriction 166 functions in the same manner as the passageways 53 and 55 of the previously described modification of the invention. It also will be noted that the cross sectional area of the restricted portion 106 of the passageway 105 cannot be varied as was made possible by the interchange of plugs 54 in the previously described modification of the invention so that the mode of operation of the cartridge illustrated in Fig. 4 can be varied only by the interchange of pistons 98 having their restricted portions of ditferent cross-sectional areas.

Referring now to Fig. for a detail description of the modification of the cartridge illustrated therein, the body member 6, adapter 12, discharge section 18, main valve 21, and spring 32, which are identical to those illustrated in Figs. 1 and 4, will not be described again and the same reference characters have been applied to the corresponding parts of each.

Positioned in the outer end of the discharge section 18 is a pilot valve support 111 having a radial flange 112 that is rigidly clamped against the annular end surface 28 of the discharge section by the housing extension 113 which is threadedly connected to the outer end of the discharge section. Sealing between the support 111 and the inner surface of the discharge section 18 is provided by an O-ring 114 seated in the groove 115 in the outer surface of the support. Extending axially inwardly from the flanged body portion of the support 111 is a cylindrical spring guide portion 116 which is fitted within the coils of the outer end portion of the spring 32 and is provided with a radial surface 117 against which the outer end of the spring is seated. A venting passageway 118 extends axially through the inner end portion of the support 111 for communication with the generally radially directed venting passageways 119 which extend from the venting passageway to a circumferential groove 121 in the radial ange 112. The circumferential groove 121 is in radial alinement with venting ports 122 in the housing extension 113. Exhaust passageways 123 extend from the venting passageways 119 to the outer end face of the support 111. An axial bore in the outer end portion of the support 111 provides a cylindrical guide surface 124 in axial alinement with the venting passageway 118, the inner end edge of which forms a pilot valve seat 125.

The outer end of the housing extension 113 is closed by an end plug 126 having an inwardly opening cylindrical recess 127 therein to provide a pilot control chamber 128. Sealing is provided between the plug 126 and the inner surface of the housing extension 113 by an O- ring 129 seated in the groove 131 in the plug 126.

Mounted in the cylindrical recess 127 for axial movement therein is a piston 132 having a valve operating plunger 133 extending through the support 112 in sliding engagement with its guide surface 124. Sealing is provided between the piston 132 and the cylindrical recess 127 by an O-ring 134 seated in a groove 135 in the wall of the recess. A pilot valve 136 is securely mounted on the inner end portion of the valve operating plunger 133 and is provided with a seating surface 137 for engaging the Valve seat 125. A passageway 138 extends axially through the valve operating plunger 133 and the piston 132 to provide communication between the main control chamber 139 formed within the interior of the discharge section 18 and the pilot control chamber 128 in the end plug 126. The outer end portion of the passageway 138 is enlarged and internally threaded to receive a plug 140 having an axial passageway 141 therethrough for limiting the rate of ow of gas from the main control chamber 139 to the pilot control chamber 128.

A cup-shaped collar 142 is mounted on the valve operating plunger `133 and extends axially outwardly in surrounding relationship with the piston 132 and cylinder 127 to provide a radial spring seating surface 143 which is spaced axially from the end wall of the support 111. A spring 144 is mounted between the end wall of the support 111 and the radial surface 143 in surrounding relationship with the spring support collar 142 to thereby urge the pilot valve 136 into its seated position. Spacer rings 145 are positioned between the collar 142 and the piston 132 to vary the compression of the spring 144, and exhaust ports 146 extend through the spring support collar 142 to maintain atmospheric pressure on both sides of the collar at all times.

The operation of the cartridge illustrated in Fig. 5 is identical to that of the cartridges illustrated in Figs. l and 4 and will not again be described. It will be noted, however, that the plug may be interchanged to vary the cross-sectional area of its passageway 141 to thereby change the mode of operation of the cartridge in the manner described in connection with the similar modification of the cartridge illustrated in Fig. 1.

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. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a work performing charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving and main control chambers each having a plurality of gas release ports, means for introducing gas into all of said chambers simultaneously to increase the pressures therein, means for controlling the increase of the gas pressure in said pilot control chamber to a rate no greater than the rates of increase of the pressures of the gas in said charge receiving and main control chambers while gas is introduced to the chambers, a differential force actuated valve positioned between said main control and pilot control chambers for movement into its open and closed positions by the pressures of the gas in said pilot control and main control chambers, respectively, to automatically release the compressed gas from the main control chamber through its release ports, resilient means urging said valve into its closed position and compressible to permit opening of the valve when the Valve opening force exerted on the valve by the pressure of the gas in the pilot control chamber exceeds the opposed forces exerted on the valve by the resilient means and by the pressure of the gas in said main control chamber, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

2. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a work performing charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving and main control chambers each having a plurality of gas release ports, means for introducing gas into all of said chambers to increase the pressures therein, means for retarding the increase of the gas pressure in said pilot control chamber relative to the increase of the pressures of the gas in said charge receiving and main control chambers, a differential force actuated valve positioned between said main control and pilot control chambers with a greater effective surface area exposed to said pilot control chamber, resilient means urging said valve into its closed position, said valve being movable into its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, to automatically release the compressed gas from the main control chamber through its release ports when the pressure of the gas in said pilot control chamber is increased to a value at which the valve opening force exerted on the valve by the latter pressure exceeds the opposed forces exerted on the valve by the resilient means and by the gas pressure in said main control chamber, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

3. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a work performing charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving and main control chambers each having a plurality of gas release ports, means for introducing gas into all of said chambers to increase the pressures therein, means for restricting the introduction of gas into said pilot control chamber to cause the pressure therein to increase at a retarded rate relative to the increase of the pressure in said main control chamber, a differential force actuated valve positioned between said main control and pilot control chambers for movement to automatically release the compressed' gas from the main control chamber through its release ports when the gas pressure in said pilot control chamber is increased relative to the gas pressure in said main control chamber by stopping the increase of pressure in said last mentioned chamber, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

4. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a Work per.

forming charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving and main control chambers each having a plurality of gas release ports and said pilot control chamber being sealed to prevent any direct communication with the atmosphere, means for introducing gas into all of said chambers to increase the pressures therein at a substantially uniform rate, a diierential force actuated valve positioned between said main control and pilot control chambers for movement into its open and closed positions by the pressures of gas in the pilot control and main control chambers, respectively, to automatically release compressed gas from the main control chamber through its release ports, said valve having an effective surface area exposed to said pilot control chamber which exceeds its effective surface area exposed to said main control chamber, a spring urging said valve into its closed position against the valve opening force exerted by the pressure of the gas in said pilot control chamber and compressible to permit opening of said valve when the pressures in said charge receiving, main control and pilot control chambers have been increased to a predetermined value at which the forces exerted on the smaller and a substantially equal portion of the larger of said elective surface areas by the pressures of the gas in said main control and pilot control chambers, respectively, are balanced and the force exerted on the remaining portion of the larger elective surface area by the pressure of the gas in said pilot control chamber exceeds the force applied to said valve by said spring, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

5. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a

pilot valve urged toward its open and closed positions by the pressures of the gas in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, said main and pilot valves being movably positioned between the charge receiving and main control chambers, and main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, resilient means urging said valves into their closed positions, means for equalizing the pressures in said charge receiving and main control chambers during charging of the cartridge, and means for increasing the gas pressure in said pilot control chamber when the gas pressure in said main control chamber is increased to move said pilot valve into its open position when the valve opening force exerted on said pilot valve by the gas in the pilot control chamber exceeds the opposed valve closing forces exerted on said pilot valve by said resilient means and by the gas pressure in said main control chamber, opening of said pilot valve reducing the closing force exerted thereon by the gas pressure in the main control chamber to facilitate opening of the pilot valve.

6. In combination, a cartridge having a charge release chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve urged toward its open and closed positions by the pressures of the gas in said charge release and main control chambers, respectively, for controlling the release of gas from said charge receiving chamber through said release ports, a spring urging said main valve into its closed position, a pilot valve urged toward its open and closed positions by the pressures of the gas in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, and a spring urging said pilot valve into its closed position, said main and pilot valves being movably positioned between the charge receiving and main control chambers and the main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, adjacent pairs of said successively arranged chambers having passageways therebetween to permit increases in the gas pressures in the main control and pilot control chambers when the gas pressure in the charge receiving charnber is increased, the increase in gas pressure in said pilot control chamber to a value at which the valve opening force is exerted on the pilot valve by the pressure in the pilot control chamber exceeds the valve closing forces exerted on the pilot valve by the pressure of the gas in the main control chamber and by the associated spring effecting opening of said pilot valve to release the gas from the main control chamber through its venting ports, and the release of gas from said main control chamber rapidly reducing the closing forces on both of said valves to permit the opening of said main valve by the pressure of the gas in said charge receiving chamber to release the gaseous charge through said lateral release ports and to retain said pilot valve in its open position during release of said charge.

7. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a pilot valve urged toward its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, said main and pilot valves being movably positioned between the charge receiving and main control chambers and main control and pilot control chambers, respectively, and exposed to the gas perssures in their adjacent chambers with the main valve having a greater eifective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, means for equalizing the pressures in said charge receiving and main control chambers during charging of the cartridge, and means forming a restricted flow path between said main control and pilot control chambers to permit an increase of the gas pressure in the latter at a retarded rate relative to the increase of the pressure in said main control chamber, said increase of the gas pressure in the pilot control chamber moving said pilot valve into its open position to release the compressed gas from the main control chamber when the gas pressure in the pilot control chamber is increased relative to the pressure in said main control chamber by stopping the increase of the pressure in the latter.

8. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a

spring urging said main valve into its closed position, a pilot valve urged toward its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, and a spring urging said pilot valve into its closed position, said main and pilot valves being movably positioned between the charge receiving and main control chambers and the main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, adjacent pairs of said successively arranged chambers having passageways therebetween for substantially equalizing the gas pressures in all of the chambers during charging of the cartridge, said pilot valve being moved into its open position to release the gas from said main control chamber when the pressure of the gas in said chambers has been increased to a predetermined value at which the valve opening force exerted on the greater eiective surface area of said pilot valve by the pressure of the gas in said pilot control chamber exceeds the valve closing force exerted on its smaller eiective surface area by the substantially equal gas pressure in the main control chamber by an amount which is greater than the valve closing force exerted on the pilot valve by its associated spring, and said main valve being moved into its open position by the pressure of the gas in said charge receiving chamber when the gas in the main control chamber is released.

9. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a spring urging said main valve into its closed position, a pilot valve urged towards its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, a spring urging said pilot valve into its closed position, said main and pilot valves being movably positioned between the charge receiving and main control chambers and the main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater eiective surface area exposed to the pilot control chamber, adjacent pairs of said successively arranged chambers having passageways therebetween for substantially equalizing the gas pressures in all of the chambers during charging ot the cartridge, and means for adjusting the force exerted on said pilot valve by its associated spring to a value substantially equal to the diiference in the values of the opposed forces exerted on the valve by the gas pressures in the main control and pilot control chambers when said pressures have been increased to a predetermined value.

l0. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a work performing charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving and main control chambers each having a plurality of gas release ports, means for introducing gas into all of said chambers to increase the pressures therein, means for retarding the increase of the gas pressure in said pilot control chamber relative to the increase of the pressures of the gas in said charge receiving and main .control chambers, a differential force actuated valve positioned between said main control and pilot control chambers with a greater effective surface area exposed to said pilot control chamber for movement into its open position by the pressure of the gas in the pilot control chamber to automatically release the compressed gas from the main control chamber through its release ports, a spring mounted in said main control chamber in compressed relationship with the end portion of said pilot valve having the smaller elective surface area to urge said valve into its closed position against the valve opening force exerted by the pressure of the gas in said pilot control chamber and compressible to permit opening of said valve when the pressure of lthe gas in the pilot control chamber is increased to a value relative to the gas pressure in said main control chamber at which the valve opening force exerted by the former pressure exceeds the opposed forces exerted by the latter pressure and by said spring, and a diiferential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

ll. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a Work performing charge of compressed gas, a main control chamber, and a pilot control chamber, said charge receiving and main control chambers each having a plurality of gas release ports and said body having a flow path therein between said main control and pilot control chambers, means for introducing gas into said charge receiving chamber to increase the pressure therein, means for equalizing the pressures in said charge receiving and main control chambers while gas is introduced to the charge receiving chamber, the cross-sectional area of said flow path controlling the rate of increase of the gas pressure in said pilot control chamber relative to the rate of increase of the pressure of the gas in said main control chamber, a differential force actuated valve positioned between said main control and pilot control chambers with a greater elective surface area exposed to said pilot control chamber for movement into its open position by the gas pressure in the pilot control chamber to automatically release the compressed gas from the main control chamber through its release ports, a spring mounted in said main control chamber in compressed relationship with the end portion of said pilot valve having the smaller effective surface area to urge said valve into its closed position against the valve opening force exerted by the pressure of the gas in said pilot control chamber and compressible to permit opening of said valve when the pressure of the gas in said pilot control chamber is increased to a value relative to the gas pressure in said main control chamber at which the valve opening force exerted by the former pressure exceeds the opposed forces exerted by the latter pressure and by said spring, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control charnber.

12. A material breaking cartridge, comprising a cartridge body having a chamber for receiving a work performing charge of compressed gas, a main control chamber, and a pilot control chamber; said charge receiving` and main control chambers each having a plurality of gas release ports, means for introducing gas into all of said chambers to increase the pressures therein, means for controlling the increase of the gas pressure in said pilot control chamber to a rate no greater than the rates of increase of the pressures of the gas in said charge receiving and main control chambers, a differential force actuated valve positioned between and exposed to said main control and pilot control chambers for movement into its open position by the gas pressure in the pilot control chamber to automatically release the compressed gas from the main control chamber through its release ports, a plurality of dished ring spring members urging said valve into its closed position against the valve opening force exerted by the pressure of the gas in said pilot control chamber, said dished spring members being partially flattened to permit the sudden and complete opening of the valve when the valve opening force exerted by the pressure of the gas in the pilot control chamber excecds the valve closing forces exerted by the spring members and by the pressure of the gas in said main control chamber, and a differential force actuated valve for automatically releasing the charge of compressed gas from the charge receiving chamber through its release ports in response to the release of the compressed gas from the main control chamber.

13. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a pilot valve urged toward its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, said main and pilot valves being movably positioned between the charge receiving and main control chambers and main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, said main valve having a passageway therethrough for equalizing the gas pressures in said charge receiving and main control chambers during charging of the cartridge, and said pilot valve having a passageway therethrough for increasing the gas pressure in said pilot control chamber when the gas pressure in said main control chamber is increased, a plug removably mounted across the passageway through said pilot valve and having a passageway therethrough for controlling the rate of increase of the gas pressure in said pilot control chamber relative to the rate of increase of the gas pressure in said main control chamber, resilient means urging said pilot valve into its closed position and compressible to permit the pilot valve to move into its open position when the valve opening force exerted thereon by the gas in the pilot control chamber exceeds the opposed forces exerted thereon by said resilient means and by the gas pressure in said main control chamber.

14. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a pilot valve urged toward its open and closed positions by the gas pressures in the pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, said main and pilot valves being movably positioned between the charge receiving and main control chambers and main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, resilient means urging said valves into their closed positions, means for equalizing the pressures in said charge receiving and main control chambers during charging of the cartridge, means forming a ow path between said main control and pilot control chambers to permit an increase in the gas pressure in the latter when the gas pressure in the former is increased, and a plug removably mounted across said flow path and having a passageway therethrough for controlling the rate of increase of the gas pressure in said pilot control chamber relative to the rate of increase of the gas pressure in said main control chamber, said pilot valve being moved into its open position when the valve opening force exerted thereon by the gas in the pilot control chamber exceeds the opposed forces exerted on said pilot valve by said resilient means and by the gas pressure in said main control chamber.

15. In combination, a cartridge having a charge receiving chamber, lateral gas charge release ports, a main control chamber, venting ports, and a pilot control chamber arranged successively longitudinally of said cartridge, a main valve for controlling the release of gas from said charge receiving chamber through said release ports, a spring urging said main valve into its closed position, a pilot valve urged toward its open and closed positions by the gas pressures in said pilot control and main control chambers, respectively, for controlling the release of gas from said main control chamber through said venting ports, and a spring urging said pilot valve into its closed position, said main and pilot valves being movably positioned between the charge receiving and main control chambers and the main control and pilot control chambers, respectively, and exposed to the gas pressures in their adjacent chambers with the main valve having a greater effective surface area exposed to the main control chamber and the pilot valve having a greater effective surface area exposed to the pilot control chamber, said main valve having a passageway therethrough for equalizing the gas pressures in said charge receiving and main control chambers during charging of the cartridge, and said pilot valve having a passageway therethrough for increasing the gas pressure in said pilot control chamber when the gas pressure in said main control chamber is increased to move said pilot valve into its open position when the valve opening force exerted on said pilot valve by the pressure of the gas in the pilot control chamber exceeds the opposed forces exerted on said pilot valve by the pressure of the gas in said main control chamber and by the associated spring.

References Cited in the file of this patent UNITED STATES PATENTS 2,083,707 Harris June 15, 1937 2,083,735 Noble June 15, 1937 2,435,116 Armstrong Ian. 17, 1948 2.591,529 Filstrup Apr. 1, 1952