US3437245A

US3437245A - Powder dispenser

Info

Publication number: US3437245A
Application number: US606071A
Authority: US
Inventors: John R Hebert; Nicholas J La Costa; Robert W Schnepfe Jr
Original assignee: AAI Corp
Current assignee: Textron Systems Corp
Priority date: 1966-12-30
Filing date: 1966-12-30
Publication date: 1969-04-08
Anticipated expiration: 1986-04-08
Also published as: SE327592B; NO120061B; JPS4939800B1; DE1625202A1; GB1170180A; IL29223A; FR1551364A

Abstract

1,170,180. Powder dispensing projectiles. AAI CORP. 29 Dec., 1967 [30 Dec., 1966], No. 59232/67. Heading F3A. [Also in Division F1] A powder dispenser comprises a body 13 of plastics material, e.g. nylon, containing the powder 25, a piston 27 movable by gaseous pressure produced by an explosive charge 49 to discharge the powder, and a shear-type closure member 17 which is sheared by the movement of piston 27 acting through a lost motion linkage 31. In operation, a handle 63 is released by removing a pin 65, a spring-loaded striker 67 then striking a primer 61 which ignites a timedelay fuse 55. An explosive propellant charge 49 is fired by fuse 55 and blows out a cover 51 and shear disc 43. The propellant gases move piston 27 towards closure member 17. When the gap between projections 17a, 27a in tube 29 of linkage 31 has closed, member 17 is sheared off and discharged together with a protective cover 23 and tube 29, followed by the powder. A shear portion 27b on piston 27 is sheared by the gas pressure if skirt 27c seizes. The lost motion linkage may alternatively comprise a solid rod between cup portions of closure member 17 and piston 27, or tube 29 may be fixed to either member 17 or piston 27.

Description

April 8, 1969 J. R. HEBERT ETAL 3,437,245

POWDER DISPENSER Filed Dec. 50. 1966 Sheet of 2 PIIIIIIIIIII VIIIIIIIIIII JOHN R. HEBERT NICHOLAS J. LOCOSTA ROBERT W. SCHNEPFE JR.

INVENTOR l/ I ATTORNEY APril 1969 J. R. HEBERT ETAL 3,437,245

POWDER DISPENSER Sheet Filed Dec. 30, 1966 JOHN R HEBERT NICHOLAS J. Lu COSTA ROBERT W. SCHNEPFE JR.

INVENTOR ATTORNEY United States Patent 3,437,245 POWDER DISPENSER John R. Hebert, Towson, Nicholas J. La Costa, Phoenix, and Robert W. Schnepfe, Jr., Timonium, Mtl., assignors to AAI Corporation, Cockeysville, Md., a corporation of Maryland Filed Dec. 30, 1966, Ser. No. 606,071 Int. Cl. B05h 11/00, 17/00; B67c 9/00 US. Cl. 222-389 Claims ABSTRACT OF THE DISCLOSURE A dispenser is disclosed in the form of a canister having a piston for expulsion of a charge of particle material from the canister. The canister has a frangible shear disc closure at one end which is surrounded by a funnelshaped end wall section, and a tube is longitudinally loosely carried in freely slidable relation between the shear disc closure and the piston by male nipples formed on each of the piston and the closure. The tube is shorter than the distance between the piston and the shear disc closure when the piston is in its quiescent position, thereby enabling initial forward propelled motion of the piston prior to rupturing force application by the tube to the shear disc closure.

This invention relates to a particle dispensing device, being especially useful for dispensing finely divided particles such as fine powder, and particularly to an arrangement which enables the facile ejection and dissemination of powder or other particulate material from within an initially closed canister or container.

It is often desirable to employ a device which will enable the substantially complete and quick ejection of a charge of particulate material into the atmosphere. Such an ejection can be obtained with a container or canister dispenser employing an explosive charge of suitable relatively slow gas-generating burning propellant for expelling the particles, but when such is attempted with an initially closed or sealed container a difficult problem is encountered in the conflicting requirements of providing a strong enough seal to prevent undesired inadvertent preopening, with a low cost lightweight canister or other container, while providing sufiicient initial pressure to cause opening of the cover at the discharge opening to enable ejection of the particulate material. Thus, if one employs a heavy-walled canister it is quite possible to have a strongly sealed discharge-opening closure element or cover and to effect adequate breakage of this strong seal and removal of the cover or closure element with a sufliciently adequate explosive charge; however, it is desirable on the other hand to employ a lightweight canister in most instances while still having a sufiiciently strong cover or closure element seal over the discharge opening, and this presents a problem in the accomplishment of rupturing, removing or otherwise opening of the cover or closure element with the requisite lesser explosive charge that can be tolerated by the lighter weight canister. It has also been found that in the case of ejecting particulate materials from a canister through the use of an explosive charge a difficult problem is often encountered with compacting of particles along the side wall area of the canister when particulate material is employed as the dispensed charge, with consequent prevention or difiiculty of 3,437,245 Patented Apr. 8, 1969 "ice ejection of these particles, particularly when the discharge or ejection opening is substantially smaller than the crosssectional area of the chamber formed by the canister side wall. It is desirable that these difliculties be overcome with the provision of a canister dispenser which is sufficiently strong to prevent breakage during normal handling, yet light of weight, and which will be relatively safe when held in the hand of an operator during operation.

It is accordingly a major feature of this invention to provide a canister dispenser which is useful in the dispensing of particulate material, and which is particularly adapted to quick expulsion of particulate material, particularly finely divided powder, while enabling employment of a relatively lightweight canister with a relatively small propellent charge, and while also permitting the employment of a relatively rugged discharge cover or closure element seal arrangement if desired.

Still another feature of the invention is the provision of an ejection element for particle material from a canister in which an integral shear-type discharge opening cover or closure element is employed, and in which pressure generated within the canister device for ejection of the material is transmitted to the discharge opening closure element by movement of a lost-motion knockout rod arrangement to facilitate shearing and removal of the closure element and consequent ease of discharge of the powder material. According to this feature, the knockout rod arrangement is arranged to permit initial forward motion of the material-ejecting piston during the initial propellent charge ignition period to prevent excess pressure build-up within the canister at the time of direct force application by the piston and rod arrangement to the shearable closure element.

Still other objects, features and attendant advantages will become apparent to those skilled in the art from a reading of the following detailed description of one physical embodiment constructed in accordance with the invention, taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a longitudinal section view of a dispenser constructed according to the invention, the dispenser being shown in its condition prior to ignition and material ejection;

FIGURE 2 is a perspective view of the dispenser of FIGURE 1;

FIGURE 3 is a longitudinal section view similar to that of FIGURE 1, illustrating the dispenser action after ignition and at the time or rupture or shearing of the discharge opening closure; and

FIGURE 4 is a longitudinal section view similar to that of FIGURES l and 3, illustrating the dispenser action after shearing of the discharge opening shear disc closure and during ejection of the material from the dispenser,

Referring now in detail to the figures of the drawings, the illustrated dispenser 11 takes the form of container or canister 13 which is preferably formed of lightweight plastic material such as nylon, Delrin acetal resin, or other suitable relatively lightweight material of good strength.

In the illustrated embodiment, one end 13a of the canister 13 is closed as initially molded or otherwise formed, and over the initially open mouth of the other end of the cylindrical canister 13 is secured a cover 15 which may be of similar material and which is suitably secured to the main body 13 of the canister as by a pressure weld or adhesive along the annular joint zone between the cover 15 and the main canister body 13, this zone being generally indicated at 16.

The cover 15 of the canister is provided with a discharge opening closure in the form of an integral shear disc 17 which is formed integrally therewith, there being an annular relatively weaker shear zone 17b formed by a thinner wall zone surrounding the shear disc and connected with the remaining portion of the cover 15. If desired, a flanged cap 23 may be provided over the shear disc to give added protection against undesired rupture of the shear disc from external forces, in which case the cap may be seated in a recess in the cover 15 as shown in FIGURE 1, as by a slight pressure fit or by holding in place with a pressure-sensitive tape (not shown). However, the use of the cap 23 is optional in many instances, as the shear disc zone may with the present invention be made sufficiently strong to prevent most accidental or other unwanted rupture of the shear disc 17 without the necessity for the additional cap 23. The cap 23 is of particular use in such instances as where the cover 15 may be subjected to extreme high pressures, such as explosive propellant pressures, prior to the firing of the dispenser itself. The charge of powder or other fill material 25 which is to be ejected is initially disposed in a chamber extending between a funnel-shaped element 21 disposed at the discharge end of the canister and an obturator piston 27 which is in the normal quiescent initial condition disposed at or near the opposite end of the canister 13. The obturator piston 27 may be provided with a suitable annular trailing pressure-responsive obturating skirt 27c to aid in sealing between the forward chamber containing the particle material to be dispensed and the propellent gas expansion zone chamber formed behind the piston 27. Propellent gases from a propellant charge arrangement, hereinafter described, are employed to impart longitudinal movement to the obturator piston 27 and thereby effect rupture of the shear zone 17a and subsequent ejection of the powder or other material 25 through the discharge opening 18 formed upon rupture and ejection of the shear disc 17.

Rupture of the shear disc 17 along the shear zone 17b is accomplished by exerting concentrated force on the shear disc as a function of movement of the piston 27. This is effected in the illustrative embodiment primarily through the medium of a force-transmitting rod arrangement generally indicated at 31. Rod arrangement 31 takes the form in the illustrative embodiment of a tube 29 which engages in complementary relationship at its opposite ends with interfacing nipples 17a and 27a formed integrally with and extending from respectively the shear disc 17 and piston 27, thereby interconnecting the piston 27 with the shear disc 17 in force-transmitting relationship. As the tube 29 is formed to provide a loose fit about both the nipples 17a and 27a, this tube will be expelled from the canister with the propellent charge, and accordingly it is desirable that this tube be formed of lightweight, yet sufficiently strong, material such as aluminum in order to keep its inertia and missile injury capability as low as possible. The tube 29 is of shorter length than the normal quiescent pre-fired distance between the opposed faces of the piston 27 and the shear disc 17, thereby enabling initial longitudinal movement of the piston 27 after ignition of the propellent charge before the piston exerts a direct force on the shear disc 17 through the medium of the rod arrangement 31, including tube 29. This is of importance in providing a safety feature which aids in preventing blow-up of the plastic body of the canister 13. Thus, if the shear disc 17 cannot be sheared or otherwise failed by the action of the piston force transmitted through the tube 29 after the piston has moved into engagement with the rear end of the tube, the piston will have moved forward sufficiently to increase the propellent gas volume enclosure sufficiently to thereby minimize pressure build-up and greatly reduce the likelihood of canister failure.

While the lost-motion force-transmitting rod arrangement 31 is illustrated in the form of a tube surrounding opposed nipples at its opposite ends, it will be apparent that an alternative although less advantageous embodiment may be formed by disposing a solid rod between the piston 27 and the shear disc while providing the lost motion through the disposition of the opposite ends of the rod in opposite interfacing cup-shaped extensions on the piston 27 and shear disc 17 respectively, the rod in such case being of shorter distance than the distance between the interfacing bottoms of the two cups or recesses in the cup-shaped extensions, and thereby enabling similar initial motion of the piston 27 before effecting direct force transmission by the piston to the shear disc. However, as indicated, the illustrated embodiment is preferred and more advantageous as the formation of the rod arrangement in the form of a tube 29 fitting over one or more nipples enables the provision of increased safety through lower Weight for this element while providing maximum column strength for a given quantity of material and weight in this element. A further alternative embodiment of intermediate form could be made by forming the tube element integral with one of the piston 27 or shear disc 17, with lost-motion engagement of the free end of the tube with a facing nipple on the other one of the piston and shear disc.

An additional safety feature is provided to aid in prevention of canister blowout in the event of excessive pressure build-up, this being the formation of a relatively thin wall annular pressure relief ring 27b in the piston 27 radially outboard of the area of immediate pressure application to the rod arrangement 31. Thus, through utilization of this pressure relief ring 27b, if the piston should be unable to move due to seizing of the obturator skirt portion 27c of the piston with the canister wall, the center of the piston 27 will be capable of forward motion in spite of this external annular seizure, as a result of the pressure relief zone formed by the ring 27b, and the center portion of the piston can thus be sheared loose from the external obturating portion upon the pressure behind the piston reaching the point where the force on the piston exceeds the shear strength of the ring 27b. In such event the propellent gases behind the piston will be ported through the sheared ring zone resulting from shearing of the thin walled ring 27b and these gases will flow into the relatively compressible powder fill 25 an dissipate in this substantially enlarged area, thus preventing pressure build-up to the point of canister rupture.

The funnel 21 which rests against the shear disc 17 is capable of effecting several functions in the operation of the dispenser, one being its centrally directed camming effect on powder and its guiding of the powder out through the discharge opening 18 upon shearing of the disc 17. The funnel can also aid in effecting the shearing of the disc 17, although this function will not normally be necessary as the rod arrangement 31 will normally effect this shearing operation without any necessity for aid from funnel 21. In some instances, however, there may be sufficient compaction of the material 25 to effect rupture of the shear disc 17 through application of the piston force to the funnel 21 and the shear disc 17 before the piston comes into direct engagement with the tube 29. As a normal rule, however, the material 25 will be sufficiently loose in its initial form that the shear disc 17 will be sheared and ejected before there is sufiicient compaction of the material 25 to effect a sufficient force on the shear disc 17 through action of the funnel 21 thereon to effect shearing of the shear disc. The funnel 21 has a central discharge opening 21a at its smaller tapered end 2111. This small open end 21b is seated on an annular step seat 19 formed on the inner surface of the shear disc 17 adjacent the annular shear zone, and the larger outer end 21c or the funnel 21 is guided by the cylindrical side wall surface of the canister 13, being held against undesired rearward motion by a shoulder formed on the inner wall of the canister adjenct the rear surface of its outer larger end 21c. The funnel 21 is initially spaced from the remaining portion of the cover by its seated position on the annular step seat 19 as shown in FIGURE 1, and upon rupture and expulsion of the shear disc funnel 21 is moved toward the main body of cover 15, and preferably seats in this forward motion position along its outer larger end 21c on the interfacing adjacent radially outer rim portion of the cover 15.

In order to provide the desired explosive propellant gas pressures for imparting motion to the obturator piston 27 and powder 25, there is provided a propellant chamber assembly 39 which is disposed in a cup-shaped recess 41 formed in the closed end 1311 of the canister 13. The propellant chamber assembly 39 is of self-contained modular construction enabling insertion into the recess 31 either before or preferably after the filling of the canister 13 with powder or other desired material 25, particularly inasmuch as the recess 41 is also completely sealed from the internal chamber holding the powder 25. This enables mutual ease and independence of the loading of the powder and the positioning of the propellent chamber assembly 39.

The propellent chamber assembly 39 may be suitably formed with outer and inner main body portions 39a, 39b, which are slidably or press fit together. Suitable sealing against pressure loss may be provided by an annular O-ring seal 47 disposed in an annular groove in the outer body portion 390, and the entire assembly 39 may be suitably retained in position within the cupshaped recess 41 as through the medium of a pair of retainer pins 45 which engage complementary transverse locking grooves formed in the adjacent interfacing wall portions of the canister end 13a and the propellent assembly body portion 39a.

The propellent chamber assembly 39 includes a propellent charge 49 which is covered by a blowout cover 51 disposed in an annular groove 53 at the inner end of the main body portion of the assembly 39. Formed at the bottom of the recess 41 of the canister 13 is a shear disc 43 which has an annular thinner wall shear zone 43a, as shown in FIGURE 1. In the seated position of the propellent chamber assembly 39 the blowout cover 51 is disposed in facing relation to the shear disc 43 and is adapted to effect blowout of the shear disc 43 upon energization of the explosive propellent charge 49, as shown in FIGURE 3.

In the illustrated embodiment the propellent charge is tired through the medium of an intermediate pyrotechnic time delay fuze 55 which is in the form of a rod of suitable fuze material such as a powder mixture of ground glass or silica, zirconium, and barium chromate, of standard time delay fuze construction, carried within a metallic tube shield 57 and communicating with the propellent charge 49 at its inner end. Over the outer end of the tube shield 57 may be disposed an apertured metallic shield such as a cover washer 59, on which rests a percussion primer 61 of conventional construction and which is adapted to be fired through the medium of a striker 67.

The striker 67 may be of suitable conventional construction and is illustrated as being carried by a pivot pin 69 which also carries an actuating torsion spring 71 which serves to effect the desired actuating movement of the striker 67 into contact with the primer 61. Prior to firing, the striker 67 is held in the ready position as shown in FIGURE 1 through the medium of an L-shaped handle 63 of conventional construction and which is hooked under a lip 39aa of the propellent chamber assembly outer body portion 39a, as seen in FIGURES 1 and 2. The handle may be suitably retained in this initial position through the medium of a releasable retainer pin Cit 65 and pull ring 65a carried in a suitable transverse bore formed in the end wall 13a of the container 13.

In operation, the dispenser 11 may be either hand-held, thrown or launched toward the desired action zone. The handle 63 is conditioned for release by removing the pull ring 65a and the retainer pin 65, and after release of the handle 63 the striker 67 is moved into percussion contact with the primer 61 by action of the spring 71. The primer initiates the burning of the time delay fuze 55 which subsequently intiates the burning of the propellent charge 49 which effects blowout of the blowout cover 51 and shear disc 43 and longitudinal movement of the obturator piston 27 toward the discharge end of the canister 13.

The obturator piston 27 is moved forward toward the shear disc 17 by the pressure of the propellent gases behind the piston 27. As the tube 29 is free to slide on the nipples 27a and 17a, without offering any substantial resistance until the gap between the effective faces of the piston 27 and shear disc 17 is closed to a distance corresponding to that of tube 29, the piston 27 will only after this amount of movement exert the full force of the pressure acting on the total piston area through the rod arrangement 31 to the shear disc 17, unless there has been suflicient compaction of the powder material 25 to effect rupture and blowout of the shear disc 17 by pressure transmission through the powder to the funnel 21 and shear disc 17 of sufiicient magnitude to shear the disc 17, as discussed hereinbefore. The shear disc 17 thus is sheared and expelled from the canister, together with the protective cover 23, and the powder material 25 is forcibly ejected through the discharge opening 18 by the continued forward motion of the piston 27. The forward motion of piston 27 is terminated by its engagement with the funnel 21.

While the invention has been illustrated and described with respect to a single preferred embodiment, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the illustrative embodiment, but only by the scope of the appended claims.

That which is claimed is:

1. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

said container having a closure spaced from said piston and securely covering an area forming a discharge opening in said container upon removal of said closure,

gas generating means for imparting motion to said piston toward said closure,

and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of shorter length than the distance between the opposing effective faces of said piston in normal quiescent position and said closure, said push rod being longitudinally spaced from one of said closure and piston in normal quiescent position of the piston, said push rod element being longitudinally substantially freely and laterally restrictedly suspended between said piston and said closure.

2. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said pitson toward said closure,

and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of lesser effective length than the distance between the opposing effective faces of said piston in normal quiescent position and said closure, said push rod being longitudinally spaced from one of said closure and piston in normal quiescent position of the piston, and thus providing a lost motion extent,

and a charge of particle material compactable to said lost motion extent in said container between said piston and said closure.

3. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure,

and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of shorter length than the distance between the opposing effective faces of said piston in normal quiescent position and said closure, said push rod being longitudinally spaced from one of said closure and piston in normal quiescent position of the piston,

said push rod element being a tube and being longitudinally freely and laterally restrictedly suspended between said piston and said closure for ejection into the atmosphere upon forward movement of said piston and rupture of said closure by force applied thereto by the tube.

4. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure,

and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of shorter length than the distance between the opposing effective faces of said piston in normal quiescent position and said closure,

one of said piston and closure having a nipple formed thereon and extending toward the other one of said piston and push rod,

said push rod having a bore formed therein and slidably engaging said nipple.

5. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure,

and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of shorter length than the distance beill tween the opposing effective faces of said piston in normal quiescent position and said closure,

said piston and closure each having a nipple extending therefrom in inter-opposing relation,

said push rod having an opening at each end fitting,

said nipples extending into the respective adjacent ones of each of said openings.

6. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure, and a force-transmitting push rod arrangement between said piston and said closure for transmitting force on said closure through movement of said piston, said push rod arrangement including a push rod element supported between said piston and said closure and being of shorter length than the distance between the opposing effective faces of said piston in normal quiescent position and said closure,

said push rod being supported between said piston and said closure through a male-female slip connection with one of said piston and closure at at least one of its ends.

7. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure,

said push rod being supported between said piston and said closure through a male-female slip connection at each of its opposite ends respectively with said piston and said closure.

8. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

a piston movably disposed in said container,

gas generating means for imparting motion to said piston toward said closure,

and a funnel shaped element disposed at the end of said container adjacent said closure and being funnelshaped across substantially the entire end of said container.

9. A dispenser according to claim 8, said funnel shaped element, resting on said closure and being slidably moveable in a direction toward said closure.

10. A dispenser for particle material comprising a container for particle material to be ejected therefrom,

9 10 a piston movably disposed in said container, about the zone of contact with said push rod and said container having a closure spaced from said piston which is of less strength than the wall strength of and securely covering an area forming a discharge said container. opening in said container upon removal of said l r References Cited gas generating means for imparting motion to said 0 UNITED STATES PATENTS piston toward said closure, and a force-transmitting push rod arrangement between X 3 said piston and said closure for transmitting force on (mile 2 5 41 X ,090 6/ 1964 Straight et al 222-504 X said closure through movement of said piston, said 10 Push arrangement. l a element ROBERT B. REEVES, Primary Examiner. supported between said piston and said closure and being of shorter length than the distance between LANE, Examine"- the opposing effective faces of said piston in normal quiescent position and said closure, 15

said piston having a safety pressure relief blow-out ring 222-541; 10265