Patent Publication Number: US-3880331-A

Title: Dispensing tool and cartridge for viscous materials

Description:
United States Patent Perkins DISPENSING TOOL AND CARTRIDGE FOR VISCOUS MATERIALS [75] Inventor: Garry R. Perkins, Cary, 11].  
 [73] Assignee: Spotnails, lnc., Rolling Meadows,  
 [22] Filed: May 21, 1973 [21] Appl. No.: 362,390  
 Related US. Application Data Continuation of Ser. No. l3l 681, April 6, 1971, which is a continuation-in-part of Ser. No. 84,046, Oct. 26, 1970, abandoned.  
 Primary Examiner-Robert B. Reeves Assistant Evaminer-Francis .1. Bartuska [57] ABSTRACT A dispensing cartridge for viscous materials adapted for use in combination with pneumatically-powered dispensers comprising a cylindrical body for containing the viscous material having for closure at one end a flat end having a dispensing opening and a tip integrally extending therefrom to direct the dispensing of said materials and for closure at the opposite end a plunger cap assembly comprising a cup shaped plunger cap having a flat closed end and having a diameter for tight sliding engagement with the inside of said cylindrical body, the ratio of the depth of said plunger cap to the diameter of the plunger cap being about 0.25 to 1 and a rim having a lip extending around the circumferential edge of one end for tight engagement with said opposite end of said cylindrical body and the other end adapted to fit in tight engagement with the end of said plunger cap opposite said closed end thereby sealing said cartridge in air tight relation. The cartridges are especially suitable for use in pneumatic dispensers which have means for mechanically disengaging the plunger cap from the lip so that the plunger cap acts as a plunger for exuding the viscous material.  
 4 Claims, 4 Drawing Figures 2 I20 I30 us 123 I35 I18 11:: glzrrji ||2 -F; iii? &#39;4 |2| 7 7 7 us I20 1 I34 1 143 131 PATENTEU W 3.880.331  
 I N VEN TOR.  
 GARRY R. PERKINS BY ATT&#39;YS DISPENSING TOOL AND CARTRIDGE FOR VISCOUS MATERIALS CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of my copending application, Ser. No. 131,681 filed Apr. 6, 1971 which in turn is a continuation-in-part of my now abandoned application, Ser. No. 84,046, filed Oct. 26, 1970.  
  Modern building methods employ adhesives and sealants extensively to permit rapid and economical building construction. It is advantageous to fasten wall paneling and other sheeting to building framework through the use of viscous sealants and adhesives. A wide variety of dispensing guns, such as caulking guns, have been available but most of these dispensers are handoperated and as such not suitable for extensive application of adhesives. Consequently, resort has been made to motor-powered dispensing guns and more advantageously to penumatic dispensing guns. One problem which arises with pneumatic dispensing guns is that standard one quart cartridges are used very rapidly and considerable time is spent changing cartridges making larger cartridges essential. Also, presently available cartridges which use their caps for plungers do not function satisfactorily in a pneumatically operated dispenser. Such cartridges are designed to have flat pistons behind the plunger and without such flat surface force the plunger is readily cocked in the cartridge tube rendering exposure of the adhesive to air and nonperformance of the dispenser. These problems are greatly magnified when larger cartridges are used.  
  Pneumatically powered dispensers, such as more fully described in my now abandoned application Ser. No. 84,046, need to utilize one-half gallon cartridges when used on construction sites for dispensing adhesive to be most efficient. Previously, to my knowledge, cartridges larger than one quart have not been available, and especially cartridges of such size having caps suitable for use as a pneumatic plunger have not been available. Even normally available one quart disposable cartridges are not suitable to contain a material as viscous as adhesive and allow efficient operation in pneumatically powered dispensers. Normally, in presently available cartridges, those having a plunger cap are not suitable for pneumatic operation. Typically such caps are constructed of cardboard or other flexible material and are shallow having a depth not exceeding a half inch. Consequently, the use of air pressure in many instances forces air beyond the plunger cap into the cylindrical body portion containing the viscous material. This can cause hardening and thereby spoilage of substantial portions of the viscous materials in addition to causing inefficient and obstinant operation. Furthermore, hardened viscous material obstacles may cause uneven distribution of pneumatic pressure against the surface of the cup during operation thereby causing wobbling which would add to the overall poor performance of the system. Also, if pneumatic pressure is used to unseat the plunger cap an undesired glob of the viscous material will be discharged.  
  Accordingly, it is an object of this invention to overcome the above mentioned disadvantages and provide a dispensing cartridge with a plunger cap which neither wobbles nor allows entrance of air into the cartridge containing viscous material.  
  Another object of this invention is to provide a dispensing cartridge which may be used with a penumati- Cally-operated dispensing apparatus which will give a free, continuous feed of the viscous material.  
  Another object of this invention is to provide a dispensing cartridge which, in combination with a pneumatically powered dispenser having a threaded material reservoir, unseats the plunger cap mechanically upon insertion of the cartridge in the dispenser.  
  These, and other objects and advantages of the present invention will become apparent from the following description and the drawings showing preferred embodiments wherein:  
  FIG. 1 is a perspective view of a dispensing cartridge of this invention.  
  FIG. 2 is a partial cross-sectional side view of a dispensing cartridge of this invention.  
  FIG. 2a is an enlarged sectional view of the plunger cap assembly.  
  FIG. 3 is a cross-sectional side view showing a dispensing cartridge of this invention mounted in a pneumatically-powered dispensing apparatus with its trigger valve depressed and plunger cap in motion.  
  FIG. 1 shows dispensing cartridge 10 which comprises cylindrical body 11 for containing viscous materials, flat end 13 at one end having dispensing opening 12 and having tip 14 integrally extended therefrom to direct the dispensing of viscous material. On the opposite end of cylindrical body 11 is opening 15 which is tightly covered with plunger cap assembly 16.  
  Referring to FIGS. 2 and 2a, plunger cap assembly 16 has rim 18 having lip 19 extending completely around the circumferential edge of the open end away from plunger cap 20. Plunger cap 20 has closed end 17 adjacent the viscous contents. Rim 18 is adapted to fit in tight engagement, preferably with the inside surface, of the portion of plunger cap 20 away from closed end 17. In its assembled form, plunger cap assembly 16 is to close one end of cylindrical body 11 by inserting plunger cap assembly 16 into cylindrical body 11 in a plugging fashion until lip 19 uniformly contacts the circumferential edge of one end of cylindrical body 11. Plunger cap assembly 16 should tightly fit the inner surface of cylindrical body 11 while in its inserted position so as to make a normally air tight seal.  
  In accordance withthe teachings of this invention, plunger cap 20 must have a depth of at least about three-quarters of an inch, and preferably about 1 inch. The ratio of the depth of the plunger cap to the diameter of the plunger cap should have a value of about 0.25 to 1, preferably about 0.35 to 0.75. Especially suitable are plunger caps having a ratio of about 0.4. Unlike the shorter depths found in the prior art it has been discovered that the use of greater depths taught by this invention offer greater and more uniform resistance to the pneumatic pressure against the inside surface of end 17 and prevent air from entering cylindrical body 11 containing the viscous material at normal pneumatic operating pressures of about 5 to about 50 psig. The greater depth of plunger cap 20 prevents wobbling and insures smooth axial traversal through the cylindrical body 1 I. Also, since there is substantially no hardening of the contained viscous material by air leakage there will be no obstacle build-up in the path of plunger cap 20.  
  In operation as shown in FIG. 3, cartridge 10 of this invention fits snugly within material reservoir 130 of the pneumatic dispensing apparatus. The dispenser apparatus shown in FIG. 3 has a housing generally shown as having grip portion 111, trigger carrying portion 112 and material reservoir carrying portion 113. The trigger carrying portion defines cylinder 114 and first air carrying channel 115. The trigger mechanism includes stem portion 116 having first spool 117 and second spool 118. The spools are adapted to move in substantially air tight relation within cylinder 114 and first air carrying channel respectively, by sealing means 119. The trigger mechanism has end 120 adapted for pistol grip type engagement most conveniently with the index finger of the operator. Grip portion 111 may contain pressure fluid container 124 in communication with the pressurized fluid supply means 122 and cylinder 114.  
  Material reservoir carrying portion 113 of housing 110 is adapted to maintain material reservoir 130 in substantially air tight communication with material reservoir carrying portion 113. Material reservoir 130 comprises cylinder 131 having threads 132 adapted to tighten the first end of cylinder 131 into substantially air tight relation with material reservoir carrying portion 1 13, and threads 133 on the second end of cylinder 131 adapted to engage cylinder cap 134 in substantially air tight relation with cylinder 131. Aperture 135 in the flat end of cylinder cap 134 is adapted to receive nozzle 14 of replaceable cartridge containing material 150 to be dispensed. Material reservoir carrying portion 113 has bossed portion 126 extending into the adjacent end of said material reservoir a distance sufficient to break the seal of plunger cap assembly 16 so that the action of screwing the cylinder and cylinder cap in tightening fashion forces the bossed portion against the flat closed end of the plunger cap disengaging the plunger cap from the lip so that relatively constant pneumatic pressure applied to the flat closed end dispenses the viscous material. Such cooperation permits utilization of a fully pneumatically powered dispenser without the requirement of applying an initial increased pneumatic pressure to disengage the cartridge plunger cap and thereby exude an initial undesired quantity of material from the cartridge. When using cartridges containing adhesives or sealants, about 10 psig is required to dispense the viscous material from the cartridge while about 40 psig or excess is required to break an effective seal around the cartridge plunger cap.  
  FIG. 3 shows the trigger mechanism fully depressed, second spool 118 moved beyond second air carrying channel 123 thus placing pressurized fluid supply means 122 in communication with the end of the material reservoir adjacent to the material reservoir portion 113 of the housing. In this condition, the pressurized fluid acts upon plunger cap thereby moving the plunger cap forward pushing material 150 out through nozzle 14.  
  It is highly desirable to use cylindrical cartridges having flat ends to most effectively seat the cartridge within the dispensing apparatus and to provide the maximum cartridge volume for the general overall size of the cartridge. I have found cartridges according to this invention may be made in one half gallon size, approximately 2 /2 inches in diameter and inches in length having a plunger cap about 1 inch deep. Such cartridges containing viscous adhesive perform very satisfactorily in a fully pneumatic dispenser as shown in FIG. 3.  
  Pressures in the order&#39;of from about 5 to 50 psig are suitable for dispensing viscous material from the cartridges of my invention. Higher pressures may be used if it is found necessary, but I have found that pressures of about 10 psig will satisfactorily apply 60,000 to 100,000 cps adhesive materials.  
  The cartridges of my invention may be made of any suitable material such as cardboard for the cylindrical body and metal for the ends or the entire cartridge may bemade of plastic materials. Any suitable combination of metallic, wood product or synthetic materials may be used.  
  While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.  
 I claim:  
  1. A pneumatically powered tool for controlled dispensing of a fluid viscous material in combination with a replaceable cartridge of the viscous material; said tool comprising a hollow housing connectable to a source of pneumatic pressure, an elongated cartridgeaccommodating section extending from said housing and having an outer end and an inner end, the latter being connected to said housing, a dispensing piece mounted on said section outer end, protruding means carried by said housing adjacent the inner end of said elongated section for extending a limited distance into said elongated section, and control means on said housing for regulating pneumatic pressure at said section inner end; said cartridge including an elongated sleeve removably mounted within said section, a dispenser cap mounted on an end of said sleeve and in engagement with said dispensing piece, a closure cap initially mounted on the opposite end of said sleeve in a static sealed position and being released from said static sealed position by said protruding means when said cartridge is accommodated within said elongated section, said closure cap, subsequent to being released from the static sealed position being movable in a sealed relation longitudinally of said sleeve towards the dispenser cap upon a predetermined pneumatic pressure being exerted thereon.  
  2. The tool and cartridge combination of claim 1 wherein said cartridge sleeve is of cylindrical configuration and said closure cap is cup-shaped and having a substantially flat center portion delimited by an outwardly facing flange portion, the latter being in slideable sealing engagement with the interior surface of said sleeve; said protruding means being a fixed boss portion formed on said housing for abutting the center portion of the closure cap and releasing same from said initial static sealed position, upon said cartridge being inserted into said elongated section and secured between said boss portion and said dispensing piece.  
  3. The tool and cartridge combination of claim 2 wherein the end of said sleeve adjacent said protruding means is provided with a rim having a portion thereof in gripping engagement with the flange portion of said closure cap to retain the latter in said initial static sealed position; the ratio of the length of the flange portion to the diameter of said cap center portion being within the range of from about 0.25 to 1.00 to about 0.75 to 1.00.  
  4. The tool and cartridge combination of claim 2 wherein said cartridge has a diameter of about 2.50 inches and a length of about 25 inches and the flange portion of the closure cap has a length of about 1 inch.