CA1067870A - Hot melt adhesive applicator of the hand held gun type - Google Patents
Hot melt adhesive applicator of the hand held gun typeInfo
- Publication number
- CA1067870A CA1067870A CA321,325A CA321325A CA1067870A CA 1067870 A CA1067870 A CA 1067870A CA 321325 A CA321325 A CA 321325A CA 1067870 A CA1067870 A CA 1067870A
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- CA
- Canada
- Prior art keywords
- valve
- gun
- adhesive
- storage chamber
- molten
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Abstract of the Disclosure A hand gun type applicator is provided for the dispensing of hot melt adhesive for use in an adhesive dispensing system. The hand gun includes novel charge valve structure adapted to interconnect with novel feed valve structure mounted on the hot melt adhesive source so as to accomplish transfer of a hot melt adhesive charge in molten form, from the source to the gun storage chamber. The adhesive is pressurized within the gun's storage chamber by a novel pressure device at least partially incorporated within the storage chamber, thereby providing the motive force to cause discharge of molten adhesive from the gun's nozzle in response to manual activation of the gun's trigger.
Description
- ~36'7~370 This application is a division of Canadian application Serial No. 286,452 filed-September 9, 1977.
This invention relates -to an applicatox generally configured in the form of a hand gun for use in a hot melt adhesive dispensing system.
Hot melt adhesive, which are usually adhesives of the . ~er~oplastic type, have recently become quite commonplace in certain industries. For example, hot melt adhesives are widely used in the assembly and manufacture of automobiles, furniture, aircraft sub-assembiies, and the like. Of course, assembly operations in these industries utilize production line techniques, and in that type of assembly where the adhesive applicator cannot remain stationary, i.e., where the operator must have freedom to move the applicator in and out or back and forth as required, a hand gun type of adhesive applicator device is used. However, efficiency on the part of the operator utilizing the hot melt adhesive hand gun is highly desirable.
It is important, therefore, that the hand gun be easy to use by the operator without unduly tiring the operator over a regular work day.
A hand-held adhesive applicator device is generally referred to as a gun because of its overall similarity to a hand gun in both configuration and operation. Each such gun is generally provided with a piston grip or handle portion, a generally barrel-shaped portion that houses the discharge valve for the hot melt adhesive, and a trigger device by means of which operation of the gun is controlled, i.e., by means of which molten adhesive discharge is controlled.
It is highly desirable that a hand-held adhesive gun 3~ provide total freedom of movement to its operator in production line or any other type assembly situations. The operator
This invention relates -to an applicatox generally configured in the form of a hand gun for use in a hot melt adhesive dispensing system.
Hot melt adhesive, which are usually adhesives of the . ~er~oplastic type, have recently become quite commonplace in certain industries. For example, hot melt adhesives are widely used in the assembly and manufacture of automobiles, furniture, aircraft sub-assembiies, and the like. Of course, assembly operations in these industries utilize production line techniques, and in that type of assembly where the adhesive applicator cannot remain stationary, i.e., where the operator must have freedom to move the applicator in and out or back and forth as required, a hand gun type of adhesive applicator device is used. However, efficiency on the part of the operator utilizing the hot melt adhesive hand gun is highly desirable.
It is important, therefore, that the hand gun be easy to use by the operator without unduly tiring the operator over a regular work day.
A hand-held adhesive applicator device is generally referred to as a gun because of its overall similarity to a hand gun in both configuration and operation. Each such gun is generally provided with a piston grip or handle portion, a generally barrel-shaped portion that houses the discharge valve for the hot melt adhesive, and a trigger device by means of which operation of the gun is controlled, i.e., by means of which molten adhesive discharge is controlled.
It is highly desirable that a hand-held adhesive gun 3~ provide total freedom of movement to its operator in production line or any other type assembly situations. The operator
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~67870 ,hould be able to orient the gun, and therefore the gun's noz~le into any spatial location desired so as to deposit molten adhesive in the exact location required on an assembly or sub-assembly to accomplish the desired bonding result in the easiest and most efficient manner. Therefore, and in the most preferred situation, an adhesive gun should be completely portable in the sense that it should not be connected with any feedstock supply source, or any power source, at all; this would allow the operator to manipulate - the gun into whatever spatial orientation is desired, no matter what the structural configuration of the workpiece, so as to achieve optimum results. However, and in the case of all hot melt adhesive gun structures known to the art, as far as we are aware, the gun must either be connected to a molten feedstock supply source by a feed hose or to an electric power source by a power cord or to both a feed hose and a power cord so orientation of the gun in that . manner desired by the operator is limited to the extent that the gun itself is encumbered by at least one hose or cord. Even with the adhesive gun so connected, it is desirable that the operator have as much freedom and use of the gun as is possible to facil~tate production efficiency and to prevent overtiring of the operator. In this connection, the flexiblity and weight of a power cord is usualIy substantially less burdensome than a hot melt feed hose, so that overtiring of the operator when only a power cord is interconnected with a hand gun is not anywhere near as great as when both a power cord and a hot melt feed hose are interconnected with the hand gu~
There are two basic systems for supplying molten adhesive to the discharge valve in a hand gun type applicator device. The first system requires an extruder type structure dap/
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incorporated in the yun's barrel to translate, within the hand gun itself, solid feedstock (e.g., in pellet or siug form) into m~lten feedstock at the discharge valve. Such is accomplished by forcing the solid feedstock through a relatively high temp-erature heat exchanger in the gun's barrel, the force being provided by, e.g., a pneumatic motor supplied with air pressure through a power cord. An adhesive gun of this type is disclosed in U S. Patent No. 3,818,930, issued June 25, 1974, and assigned to the assignee of this application.
The second system of supplying molten adhesive feed-stock to the gun's discharge valve is to transmit the feedstock in molten form to the gun through a feed hose from a separate supply source. In this system the molten feedstock is translated from solid state (e.g., pellets, bulk, billet or chunk) to molten state at a separate location by a melter structure separate from the hand gun itself. ~he molten feedstock is then pumped from the melter structure to the hand gun through the gun's molten adhesive feed hose. Adhesive guns adapted to function from an - independent molten feedstock supply source in this manner are illustrated in U.S. Patent No. 3,543~968, issued December 1, 1970, and in U.S. Patent No. 4,006,845, issued February 8, 19i7, both patents being assigned to the assignee of this application.
Independent supply structures for melting and forwarding moltsn theremoplastic adhesive material through a feed hose to a separate hand gun structure are illustrated in U.S. Patent No. 3,815,788, issued June 11, 1974, and U.S. Patent No. 3,827,603, issued August 6, 1974, both patents being assigned to the assignee of this application.
In high speed assembly or production line situations, it is oftentimes desirable to use that type adhesive gun structure ~IL067~37~
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which is supplied with molten feedstock from a totally separate Ijhot melt adhesive source such as described in the second system i! above. This for the reason that this type system provides a ¦¦]arge and continuous supply of molten feedstock to the hand gun ~¦and, therefore, to the gun's operator. This precludes the neces- ¦
¦¦sity of continuously loading and reloading the gun with solid ,Ifeedstock by the operator during use, and the attendant time lost ¦
¦in connection therewith, such as required in the first system l¦described above. ~owever, and for hand guns used with the llsecond system, each of these hand guns must be connected directly !~ at all times to the separate molten adhesive source. This ,IConnection~ as previously mentioned, is maintained through lja hot melt feed hose, which may or may not be provided with ¦¦heater elements along the length thereof.
¦i The necessity of a hot melt feed hose in the second hot melt adhesive dispensing system presents several operating disadvantages, from a practical standpoint, in certain end use situations. First, and from an economic standpoint, each hand gun is generally supplied with its own molten adhesive 1! source. In other words, a separate and individual melter ~` ! structure remote from the gun is provided for each hand gun becaus the molten adhesive source must be connected directly at all times lwith the hand gun through the hot melt feed hose. Second, and l! from an operating standpoint, the hot melt feed hose itself adds ¦Isubstantial weight to and restraint on the hand-held gun as used ¦~or manipulated by the operator. In otller words, not only is thc ¦¦hot melt fecd hose itself vcry heavy (relative to an electric cord ¦¦usually also interconnected with the hand gun for purposes of l¦controllincJ the temperature of the heater block within the hand Igun), but the hot melt feed hose also imposes a substantial ' ' .
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restraint on the gun (relative to the electric cord) when the gun ~ust be manipulated into nooks and crannies of a workpiece by an operator. In this latter connection,~
manipulation of the hand gun into nooks and crannies by the operator, as dictated by the structural characteristics of the workpiece, lS impeded by interconnection with the hot melt feed hose and this tends to tire an operator's arm, thereby causing t~e operator to lose efficiency more quickly than would be the cas~ if no such hot melt feed hose were attached.
The difficulties and problems associated with prior art hand gun type hot melt adhesive applicators are overcome by the present invention which pro~ides a hand held gun for dispensing a molten fluid adhesive, the gun comprising a storage chamber within which a charge of molten fluid adhesive is stored, a nozzle through which the molten fluid adhesive is discharged onto a workpiece, a discharge valve for controlling discharge of the molten fluid adhesive through the nozzle, a pressurizing device within the gun, the pressurizing device maintaining that molten fluid adhesive within the storage - chamber under pressure during discharge of fluid adhesive from the gun, and a charge valve connected with the storage chamber, the charge valve permitting flow o~ a molten fluid adhesive charge one way through the valve into the storage chamber for charging and recharging the storage chamber, but preventing flow of fluid adhesive from the storage chamber out through the charge valve to atmosphere.
Other features and advantages of this invention will be more apparent from the following detailed description, taken .
10~i7870 - in.conjunction with the drawings, in which:
Figure 1 illustrates a hot melt adhesive dispensing system of the hand-held gun type in accord with the principles o~ this invention;
. Figure 2 is a cross-sectional view taken along the .. -- 7 --~)67137~
. I ~ . ., ¦¦ center longitudinal plane of a first elnbodimellt of a hand gun ¦¦ structured in accord with the principles of this invention; .
Figure 3 is a cross-sectional view taken along the center longitudinal plane of a second embodiment of a hand gun also structured in accord with the principles of this invention;
Figure 4 is a cross-sectional view of a first embodi-ment of a molten adhesive source in accord with the principles ¦ of this invention, that molten adhesive source being shown in operative combination with a cross-sectional view taken along the center longitudinal plane of a third embodiment of a hand gun also structured in accord with the principles of this invention; : . .
Figure 4~ is an enlarged view of the feed valve/charge valve structure illustrated in Figure 4;
~:~ , Figure 5 is a side view of a second embodiment of a molten adhesive source in accord with the principles of this . ~ invention; and ; ¦Figure 6 is a cross-sectional view taken along line 6-6 j of Figure 5.
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Th _ and lleld Gun .
A first cmbodi.mcnt.10 of a hand (Jun is i].lustratcd in Figure 2. As shown in that Figure, thc hand gun 10 includes a heater body 11 disposed within a housing 12. The housing 12 is configured to define a barrel portion 13 having longitudinal axis 14, and a storage chamber 15 portion having longitudinal axis 16, in a vaguely Y-shaped configuration. Likewise, the one-piece heater body 11 includes a barrel portion 17 having bore 18 coaxially disposed with the longitudinal axis 14 of the housing's barrel portion 13, and a feed portion 19 having bore . 20 coaxially disposed with the longitudinal axis 16 of the housing's storage chamber portion 15. The heater body's bores .
. ¦18, 20 are connected by connector bore 21. The storage chamber portion 15 of the housing is in the nature of a tubular shell 22 threadedly received as at 23 to the aft end of heater block.
, an O-ring 24 being inte~posed between that end of the shell ¦and the heater block to provide a seal tight relation therebetween ¦The gun's housing 12 is mounted in fixed relation with storage ¦¦chamber 25 defined by shell 22, and with heater body ll, in an ¦
~limmobile fashion through collar 2G frictionally embracing shell 22 and by other structure, not shown. ~ handle 27 structure, - ¦
illustrated in phantom lines, extends rearwardly from the aft ¦ end of the housing's barrel portion 13, the handle structure itself forming no part of the structure of this invention. Note ¦ particularly that the longitudinal axis 28 of the handle 27 is ¦disposed para].lel to the longitudinnl axis 16 of thc housing's ......... Istorage chamber 25.
The barrel portion 19 of the heater body 11 (which is fabricated of a heat conductive material) defines a bore 18 coaxially aligned with longitudinal axis 14 of the housing's ~ ~ , _g_~ ~ .
"'''~ ' . ~o6t7870 barrel 13 as prevjously mentioned. Tllis bore 18 is the dischargc bore for the molten adhesive. A nozzle 30 with longitudinal bore 31 is threaded, as at 32, into the interior of the dis-charge bore 18, i.e., into the heater body 11, at the discharge end of the gun 10. The heater body 11 also receives cartridge heaters, not shown, in bores, not shown, in the heater body that are parallel to axis 16 of the heater body. The temperature of the heater body 11 is controlled by thermostat 33 electrically ¦ connected to the electrical resistance hea-ter cartridges, not ¦ shown, and to a powersource, by wires, not shown.
¦ A discharge valve 34 is positioned within the discharge ¦bore 18 interiorly of the heater body 11. The discharge valve 34 includes a valve stem 35 and a valve head 36 fixed thereto, the stem being coaxially disposed within the discharge bore 18.
The valve head 36 is adapted to seat against valve seat 37 in sealing fashion, the valve seat heing press fit into the bore !¦ 18 against shoulder 38. A seal in the nature of a compressible ¦¦bellows 39 ls fixed at one end 40 to the valve stem adjacent the ¦¦valve head 36 and is fixed at the other end 41 to collar 42 ¦ ~the valve stem 35 is reciprocable throuyh the collar 42). The ¦collar 42 is held in fixed locati~n within the discharge bore ¦18 by virtue of being formed integral with retainer plate 43.
- ¦! That retainincl plate 43 is bolted by screws 44 to aft end face 45 of the heater body 11. The bellows 39 functions to allow longitudinal movement of the valve stem 35 while maintaining a . l scal to prevc~nt lenk;l~Je oE molten aclllesive Eeedstock Crom dis-charge bore 18 through the aEt end 45 of that bore into housing interior 46, thereby allowing valve head 36 and valve seat 37 to function as a discharge valve 34 as permittcd by the trigger 47 (describcd in detail below). The discharge valve 34 assembly ~ ' ' '.
1 ~067870 is hydraulically unl)llanaocl ;uc1) th;ll tl~c valvc hcad 36 and stem 35 wi].l movc rcarwardly duc to tllc hycll-aulic pressurc of molten feedstock in thc clischarge bore 18 (as vicwed in Figure 2) when the tri.gyer 47 is activated by an operator. This, of eourse, allows the molten adhesive feedstock to be discharged through the no~zle 30 onto a workpiece.
The gun's trigger 47 is adapted to coopcrate with eompression spring 50 loaded against a stop 51. End 52 of the valve stem 35 is slidingly received in bore 53 defined by the stop. The trigger 47 functions only to withdraw the stop 51 against the compression spring 50 bias, thereby allowing the diseharge valve 34 to open due to hydraulic pressure only of the molten feedstock (as previously described), and slidability of valve stem 35 in the stop's bore 53. The stop 51 is slidingly ¦reeeived in bracket 54, the bracket being formed integral with ¦the retainer plate 43. Compression spring 50 also bears against ¦the underside of that braeket's crown 55. Beeause of this ¦strueture, eompression spring S0 forces stop 51 continuously ¦against valve stem 35, thereby continuously biasing the valve ~head 36 toward the discharge valve 34 closed attitude (shown lin Figure 2) where the valve head is seated on the valve seat ¦37. An adjusting bolt 56 ~s threaded, as at 57, into the stop's shaft 58, that adjustment bolt extending through Eitting 59 in the aft end of the gun housing's barrel portion 13 into the interior of handle 27. By rotating bolt 56, the compression .
¦on spring 50 is increased or decrcasccl as dcsircd, tllexeby acljust~
¦ing the finger pressure required to operate the trigger 47.
¦ The trigger 47, which is carried within the gun's ¦handle 27, includes a thumb 48 that defines an elongated slot 49 through which the adjustment screw 56 passes, the adjustment Lo~7870 `
screw's head ~(~ causing Lho triggcr's thumb 48 to be captu~cd betwcen the screw's head and the lever Eace 60 at thc aft cnd of fitting 59. When the trigger 47 is pulled upwardly (as shown by directional arrow 61 in E'igure 2) by an operator's index finger, the trigger's thumb 48 .bears agai.nst lever face ¦ 60, thereby causing the s.top 51 to be drawn rearwardly against the bias of the compression spring 50 so that the discharge ~ . valve 34 can open in response to the hydraulic pressure of the : molten feedstock in discharge bore 18. When the operator releases the trigger 47,~ compression spring 50 moves the stop ; 51 into abutting contact with the valve stem's end 52, thereby closing the discharge valve 34 since the compression spring . pressure overcomes the molten feedstock's hydraulic pressure.
. ¦ The molten adhesive storage chamber 25 is provided .~ ¦with a pressurizing device therein, that device being in the form of a collapsible bladder 65. The bladder 65 is 1n the nature of a balloon positioned within the storage chamber 25, the collar 66 of the balloon extending out through port 67 at . the end of the chamber, and being restrained against the exterior .
20 end face 68 of that chamber by washer 69. Threaded fitting 70 is also located in the port 67, that fitting's flange 71 being ¦seated in recess 72 defined in the interior end face of the : ¦¦chamber end. Nut 73 cooperates with threaded section 74 of the fitting 70 to mount that fitting to the chamber's shell 22 . and, also, to restrain the bladder 65 in place within the chamber 25. Threaded sections 75, 76 of fitting 70 are adapted ... . to interconnect with a compressed air hose 77, as illustrated in Figure 1, for providing connection wi.th a compressed air source, not shown, to the interior oE thc bladder 65. Thc bladder 65, in responsc to the compressed air, is adapted to 7~ 70 I , . .
move between a fully collapsed attitude illus~rated in solid llines in ~igure 2 and a fully extended position illustrated ¦by phantom lines in Fiyure 2, the molten adhesive witilin the i storage chamber 25 being pressurized at the pressure of the ¦compressed ,air within the bladder 65 so as to provide the motive force for discharging adhesive through the gun's nozzle 30 in jresponse to opening of the discharge valve 34, as operated by the trigger 47 and as previously described. Pressure of the llcompressed air within bladder 65 remains constant at the air I,¦line 77 pressure no matter how much or how little molten adhesive ¦lis in storage chamber 25 since the bladder 65 is continuously 'open to that air line 77. On/off control of compres,sed air through hose 77 into bladder 65 is at a remote location, not shownli A normally open spring loaded check valve element is slidlingly disposed in bore 20 of barrel portion 19. Valve 4 element is retained inbore 20 by a lock pin 5 which is forced ¦ into an inters,ecting bore which is at a right angle to bore 20.
'~ Valve 4 has a conical head which cooperates with the I! tapered end wall 6 of barrel portion 19 to form a valve.
l' Valve 4 also has a reduced diameter portion or under-~cut 7 which mechanically cooperates with lock pin 5 to permit limited axial movement of valve element 4 but still retained in ,;bore 20. ~ compression spring is disposed in one end of bore jl20 and engages the tail end of valve 4 and urges valve 4 to the ,right against lock pin 5 and to an open position.
Eu~ L v;~lve cl~lllcll~ r~vc~ c ~L~
¦65 from being extruded into bore 20 as adhesive is forced from ¦chamber 25 by the bladder 6S.
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charge valve 80 is connected with bore 18 of the ¦heater body 11 downstream of the dischargc valve's valve head i 36/valve seat 37. The charge valve 80 functions to interconnect hand gun 10 with a molten adhesive source 100, described in lldetail below, for purposes of charging the storage chamber 25 ¦¦with molten adhesive in a manner described in de~ail below.
The charge valve 80 inco~porates a cylindrical valve body 81 threadedly connected with heater body 11 as at 82, the body l¦defininy axis 83 that is disposed substantially normal to the 10 ¦!longitudinal bore 14 of the bore 18. A port 85 is provided ¦¦centrally of the valve body 81, that port opening into valve ! bore 86 defined by the valve body 81. The port 85 and valve bore 86 cooperate to define valve seat 87. The charge valve's seat 87 is adapted to receive a ball 88 valve element in seated relation thereon, the ball being spring closed at all times by compression spring 8~. The charge valve's compression spring ¦¦89 is maintained in compressive relation with the ball 88 valve element by spring retainer clip 90 which seats in groove 91 defined in the interior surface of the valve bore 86. The ,,charge valve 80, as is apparent from its structure, is a one--l¦way valve in the sense that it can only be opened to receive imolten adhesive flow into the heater body's bores 18, 2], 20 from ¦exterior of the gun 10. In other words, mol-ten adhesive flow ¦Ifrom the heater body's bore 18 out through port 85 of the charge jlvalve 80 is not possible as any pressure exerted on the ball 'l¦88 valve element from the interior of heater block'~ bore 18 lisimply serves to further press or force the ball 88 valve element ¦
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. 1 1067870 ~agains-t the valve seat 87. Conversely, and as is explained in greater detail below, the molten adhesive charged into the gun's storage chamber 25 from the molten adhes'ive source . lllO0 flows first through the charge valve 80 into valve bore : !¦86, then into discharge bore 18 of the heater body 11, there after through connector bore 21 and bore 20 in the heater body, and finally into the storage chamber 25 itself. Chary-ing flow of the molten adhesive into storage chamber 25 licollapses the bladder 65 into the solid line or substantially lifully charged attitude illustrated in Figure 2. The charge llvalve's body 81 also mounts a dovetailed adapter 84 on the ,exterior end face thereof, port 85 opening through the adapter .
84. The dovetailed adapter 84 is in the nature of a connector jlwhich permits the gun 10 to be interconnected with the molten ¦¦adhesive source 100 for charging the gun's storage chamber ¦¦25, as referred to above and described in detail below.
In use, and once the gun's storage chamber 25 has been fully charged with molten adhesive, high pressure air iis introduced into the bladder 65 through air fitting 70 and ¦i supply hose 77. Thereafter, and when the gun's trigger 47 i! is activated by an operator, the discharge valve 34 operates ¦¦as earlier described to permit molten adhesive to be dis-¦~charged from the gun's nozzle 30. The pressure within the . ¦ibladder 65 remains substantially constant no matter what the . ¦
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¦¦spatial a-t~itude of the bladdcr within the storage chamber 25, ¦¦i.e.l no matter how much molten hot melt adhesive remains in 'l¦or has been discharged from the storage chamber. The compressed I I air source remains at constant pressure, and that source is continuously and directly connected with the bladder 65.
Thus, even pressure is maintained on the molten hot melt ad- ¦
! hesive within the storage chamber 25 so as to force the adhes-; i¦ive out of the gun 10 at an even rate no matter what quantum ¦lof molten adhesive remains within that chamber until the last lof the molten adhesive has been discharged.
; Ii A second embodiment 78 of the hand held adhesive ¦gun, also in accord with the principles of this invention, ¦is illustrated in Figure 3. The reference numbers used in jlFigure 3 are identical to those used in Figure 2 Eor identical parts. The primary differences between the Figure 3 em~odi-ment and the Figure 2 embodiment, previously described, is in the structure of heat block 79 and the pressurizing device 92.
In other words, the Figure 3 hand gun 78 structure incorporates llthe same housing 12 structure, the same discharge valve 34 I'structure, the same handle 27 structure, the same nozzle 30 jlstructure, and the same charge valve 80 structure as with i jthe Figure 2 embodiment. -l In the second hand gun embodiment 78, the heater ¦Iblock 79 is oE a slightly difEerent structural conEiguration ¦Ithan that SllOWIl EO1' ~hc heater block 11 in ~hc Figurc 2 on~odilncnt Il , . ..
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. ` ' - ' ' . ~lowever, and as with hea~cr block 11, tllc heater body 79.also has at lcast one heater cartridye, no~ shown, mounted therein.
The heater block 79 in the second embodiment 78 has a bore 9i . coaxial with the axis 16 of the storage chamber 25, w~slich bore 93 directly connects with the block's discharge bore 18, instead of interconnecting with that bore 18 through a connector bore 21 as in the case of the Fiyure 2 embodiment. rrhe heater block 79 in this second hand gun 78 embodiment is formed integral with a tubular casing 94 that extends rearwardly of the heater 10 - body 79 relative to the gun's nozzle 30. The tubular casing 94 defines the molten hot melt adhesive storage chamber 25 for this hand gun embodiment. The tubular casing 94 is closed at . its rearmost end by an end cap 95 threadedly engaged, as at 96, with the tubular casing.
The pressurizing device 92 of this hand gun 90 includes a cup-shaped piston 97 located within the tubular casing 94, that piston being illustrated in the fully retracted attitude in solid lines in Figure 3 and in the fully extended attitude . in phantom lines in Figure 3. The pressure wall 98 of piston 97 l abuts front end face 99 of chamber 25 when the chamber is empty.
The piston 9i is spring loaded by a compression spring 64 that ¦is seated against the piston's pressure wall 98 at one end and ¦
¦ abuts against end cap 95 at the other end. The pressure generated ¦by piston 97 against the molten adhesive within the storage ¦chamber 25 is, of course, caused by spring 64 pressure.
In us;o, tllc s,tora(Jc cl)a~ or 25 .i.~ ir-.;t ~ully cllaL-J~l ... with molten hot melt adhesive through charge valve 80 so that the piston 97 is fully retracted as illustrated in solid lincs in Figure 3 (thc rear face 103 of the piston abutti.ng against .
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the interior face oE end car~ 95 to define that rearmost or fully retracted position). During charging through charge valve 80, the charging pressure of the molten adhesive must be sufficient to overcome spring ~, pressure so as to cause piston 91 to retrac from the phantom line to solid line position. Thereafter, and when the trigger q7 is activated by an operator, operation of the discharge valve 34 is as previously described in connection with the first embodiment. In this connection, pressure exerted on the mol-ten adhesive within the storage chamber 25 by piston 97 forces the molten hot melt adhesive out through the gun's nozzle ` 30.
A third embodiment 110 of a hand heId gun fabricated in accord with the principles of this invention is illustrated in Figures 4 and 4A. As shown in Figure 4, the third embodiment 110 includes a housing 111 having a barrel 112 portion and a handle 113 portion, the barrel portion defining longitudinal axis 114 and the handle portion defining longitudinal axis 115, those axes interconnecting at an acute angle as ¦ illustrated. The housing 111 incorporates the barrel 112 portion' ¦ and the handle 113 portion as a single integral part. This ¦ embodiment 110, as is apparent from Figure 4, therefore presents a housing more in the nature of a classic pistol configuration.
A one-pie-ce heater block 116 and storage chamber 117 structure, of a generally tubular geometry, is mounted within tile housing 111 coaxially with the longitudinal axis 114 of the gun's ¦ barrel 112 portion. This one-piecc structure incorporates the heatcr body 116 with longitudinal discharge bore 118, and the storage chamber 117 as defined by longitudinal casing 119, that chamber opening directly into discharge bore 118 at one end and being closed at the other end by end cap 120. The heator body 116 d storage chnmber ~11 eleme~t 1S ~lso provided:
, -]7-6787!~t with cartridge heaters, not shown, for maintaining a desired temperature level of that element 116, 119 so as to keep thc molten adhesive within the storage chamber in a molten state after same has been charged into the gun from a separate molten adhesive source 101. The cartridge he~ters are electrically connected with a thermostat 123 also mounted to that element 116, 119 for the purpose of sensing the temperature thereof, the cartridge heaters and thermostat being also electrically - connected with an electric power source in a manner well known to those skilled in the art.
The gun's discharge valve 122 is located in discharge bore 118 of the heater bbdy 116, a cross fitting 121 which forms the valve body of discharge valve 122, being threadedly received at one end as at 124 within the other end of discharge bore 118. The other end of the cross fitting 121 is threadedly received as at 125 in the gun's nozzle 126, that nozzle defining nozzle bore 127. A plunger shaped valve element 128 is coaxially received within the valve body's bore 129 as defined ¦by the cross fitting 121. The valve element 128 includes ¦head 130 adapted to seat against valve scat 131 defined at the forward face of the cross fitting 121. The stem 132 of the valve element 128 is provided with a flange 133 at that end opposite the head 130 end. A compression spring 134 is interposed between the forward face of that flange 133 and ledge 135 defined on the interior surface of bore 129 so as ¦to continuously bias tho valve's head 130 Loward tllc closcd ¦attitude as illustrated in Figure 4. Since the valve's head ¦130 is spring loadcd closed, any prcssure on the inner face of thc- valve's head exceeding the compression spriny 134 pressure will causc tlle valve to open, thereby permitting discharge of 11 ` ~06'7~37~
mol.ten adhesive from thc CJUn ~s storage chamhor 117 throu~Jh thc .
nozæle 126 onto a worlcpiece as doslred.
1~he charge valve 138 in the hand gun 110 is generally similar.to the charge valve ~0 in the Figures 2 and 3 embodi-: ment except that the charge valve axis 139 is normal to the ¦axis 114 of the storage.chamber 117. Further, the charge valve's adapter 140 is no-t dovetailed, i.e., is simply a f-lat, plate-shaped flange. ~s in the Figure 2 and 3 embodiments, 10 and 78, the charge valve 138 of the Figure 4 embodiment 110 incorporates a ball 141 valve element adapted to seat against valve seat 14~ defined in bore 143 of the valve body 144. The ball 141 valve element is spring 145 loaded against that seat . 142, the spring being trapped by retainer ring 146 seated in groove 147 on the interior face of the valve bore 143.
The pressurizing device for the hand gun 110 is an .
; air powered piston 150, the piston being cup-shaped in configu-ration. The piston 150 is slidingly received within the . cylindrical bore 151 that constitutes storage chamber 117.
. n O-ring 152 is interposed about the periphery of the piston adjacent the pressure face 153 thereof so as to mai.ntain a fl~id ti~ht seal between the piston and the storage chamber's wall 151. The piston 150 is retained within the storage chamber 117 by abutment against end cap 120 at one end (see . solid line position in Figure 4), and abutment against ledge 154 of the chamber at the other end (see phantom line position in Figurc ~).
. . The piston 150 is powered by pressurized air from a compressed air source, not shown, which is interconnccted Wit]
the hand gun 110 through compressed air feed hose 156. As 30 ~ strated in ~igure 4, the compressed air hose 15G interconnects 87~) wi-th toc 157 Eormed intcgr,ll wi~h the hcatcr bloc~ 116 and storage chamber casing 119, a thread~d fi~ting 158 and nut 159 being providcd for that purpose. Air bore 160 connects the compressed air feed hose 156 with the interior 161 of the cup-shaped piston 150, that bore including a section 162 milled out in the end cap 120 which permits air to be continuously fed from tha~ section 163 of the bore within the one-piece body ¦ 116, 119 continuously into the interior of the piston even when the piston abuts end cap 120.
A control valve 164 is interposed within that air bore 160, the control valve being connected with trigger 165 of the hand gun 110 so as to permit controlled operation of the gun by an operator as desired. The gun's trigger 165 is pivotally mounted by pin 166 to handle 113 of the gun. The control valve 164 includes stem 167 coaxially disposed in valve ,~ bore 168, the stem including a valve element 169 and a stop element 170. The stem 167 is spring 171 loaded into that attitude illustrated in Figure 4; in that a-ttitude the compressed air source is shut off from the piston 150 to establish the nonoperative attitude. The valve element 169 is positioned and maintained in this nonoperative or off attitude by stop 170 being seated against ledge 172 defined in the valve bore 168.
The exterior end 173 of the valve stem is simply slidingly contacted with surface 174 of the gun's trig~er 165.
In use, the third embodiment 110 of the hand gun is chargcd wi~l~ mo]~c~ ot molt adllcsivc EJ:OIII;I scpar;l~c nlol~cl~
adhesive source 101 with the control valve 164 structure in the nonuse or off attitude illustrated in Figure 4. ~s is particu-larly apparent fxom that Figure, tlle piston 150, which is disposed in the phantom line attitude after all molten adhesive ~ -20-....
: I 1~)67~37al within the storagc chamber l17 has been exl~au!iLed, is returned to thc solid line attitude as molten adllesive is recharc3ecl into the storage chamber. Any air trapped within the storage chamber 117 to the rear of the piston 150, i.e., within space 161, is exhausted back through the grooye 162 and bore 160 into the valve bore 168 behind the valve element 169 and out through exhaust port 163. In other words, exhaust port 163 permits the piston 150 to move rearwardly, as illustrated in Figure 4, ¦back into the solid line or completely charged attitude with ¦ little resistance as any air trapped within the storage chamber 117 exhausts through the exhaust port. When use of the gun 110 by an operator is desired, the trigger 165 is simply pulled, thereby moving the control valve element 169 to the right as illustrated in Figure 4 to admit compressed air into bore 160 and groove 162 behind piston lS0. The pressure thereby generated on the molten adhesive within chamber 117 by the piston 150 overcomes the pressure of compression spring 134. This forces the valve element 130 off valve seat 131 and permits molten ¦adhesive to exhaust through the gun's nozzle 126. When discharge of molten adhesive is to be stopped, the trigger 165 is simply released with the result that valve spring 134 closes the dis- ¦
charge valve 122. This opens the space 161 in storage chamber 117, i.e., the space behind the piston 150, to atmosphere through ¦the exhaust port 163, thereby eliminating high pressure on the molten adhesive within the storage chamber 117. This, in turn, permits the disc:har(Je valve's compression sprin(J 13~ to c]x>sc the discharge valve 122, thereby stoppincJ clischarcJc oE molten adhesive through the nozzle 126.
'~
l'he Molten ~dhes.~ve_Source ' A fi.rst cmbodi.mcnt 10]. oE tllc moltcn adllCsiVC sourcc adapted for use with the hand gun 110 illustrated in ~igures 4,4a is illustrated generally in Figure 1 and in detail in Figure 4. ~s shown in Figure 1, the hot melt source 101 includes a molten adhesive vessel 205 positioned on top of la stand 206. The vessel 205 itself is provided with a feed ¦valve 207 in the floor 208 thereof, the feed valve being prGvided.
. jwith structure, as described in detail below, which permits periodic and -temporary interconnection of the hand gun 110 therewith. The pressure vessel is surrounded by insulation walls 209, those insulation walls being protected from the environment by a sheet metal casing having side walls 210 as well as a cover wall 211. ' '.
The molten adhesive vessel 205 is closed at the top by a lid 212 structure. It is, of course, through opening . of the lid 212 that the vessel 205 may be charged with large ¦quantities of hot melt adhesive for purposes of maintaining ¦a ready supply of molten adhesive to the hand gun 110. The lid 212 structure comprises a frame 213 connected to the top edge ' 214 of the'vessel 205 by bolts 215. The frame 213 supports the lid 212, and the lid is pivotally mounted on axis 216 on the frame for opening and closing the vessel 205 to atmosphere .
through access opening 217. The lid 212 includes a catch 218 at one end thereof, the catch being adapted to interconnect with the framc 213 for mailltaining the li.d in a c].osed attitudc.
... he lid 212 also includes an O-ring 219 on the underside for sealing'the lid to the frame 213, thereby maintainincJ thc ressurized integrity oE the vessel's interi.or 220. ~ manually perable pressure relieE valve 221 is also providcd in the lid 212.
-22- ' ~
~067870 1' ij .
¦ l'he pressurc rc].icf vai.ve 221 compriscs a valvc e].cmcnt 222 wi~h valvc hcad 223 on tllc bottom o a !;~CIII 224, ~hc valvo hcad being seated against the underside 225 o~ the lid with a seal ~ ¦being maintained through use of an O-ring 226. The valve head .1 ¦223 is spring loaded into sealed relation with the underside-of the lid by compression spring 227 interposed between the top side 228 of the lid and flange 229 at the top of the valve stem 224.
A feed valve 207, as previously mentioned, is incorporatT
ed into the floor 208 of the source vessel 205. The feed valve 207 includes a bore or tubular slideway formed integral with the vessel itself, that slideway defining a bore 230 having a longi-tudinal axis 232. The tubular slideway 230 carries the feed valve 207 in slideable or reciprocable relation therein. The . feed valve 207 includes valve body 233 of generally T-shaped cross section, that valve body 233 being comprised of tubular : section 234 and flange 235 at one end thereof. The valve body 233 and, hence, the valve 207, is slideable within the tubular . slideway 230 between an inner limit defined by ring 236 received in an annular groove on the interior surface of the slideway 230, , and seat 237 also defined on the.interior surface of the slideway ¦
¦ 230. In other words, and when in the fully closed attitude as ' ¦
shown in Figure 4a, the valve body 233 is seated against the . ¦r.ing 236, the valve body being continuously biased into that position by compress'ion spring 238 interposed between that valve body's flange 235 and ledge 239 defined in the slideway 230.
When in thc acti.ve or flow attitudc, as il].ustratcd i.n Fig. ~, thc travel limit of valve body 233 is defined by seat 237. A firstO-rir g 240 is rcceivcd in the periphery of the valve'body's flange 235 to 1~6787~
maintain a sealing relation between the interior 220 of the vessel 205 and atmosphere. A second 0-ring 241 is carried in the outer fa~e of the valve body's tubular section 234 for cooperation with the exterior face 242 of each hand gun's adapter 140 as described hereinafter in detail.
The feed valve 207, in addition to valve body 233, also includes a ball 243 valve element adapted to seat on seat 244 defined in bore 245 through that valve body 233. The ball 243 valve is spring loaded toward the valve closed or seated attitude, as illustrated in Figure 4A, by compression spring 246. The compressian spring 246 is retained in loaded relation with the ball 243 valve by ring 247 carried in a groove defined on the interior surface of the valve bore 245. Thus, and as illustrated in Figure 4A, with the feed valve 207 in the non-active attitude, the ball 243 valve is spring 246 loaded closed against seat 244 of the valve body 233~
and the valve body 233 is spring 238 loaded against ring 236 of the slideway 230.
A gun coupling 250 is formed integral with the exterior end of slideway 230, the coupling serving to interconnect the hand gun 110 with the vessel 205 when charging or recharging of the gun with molten adhesive is desired. The coupling 250 is in the nature of a flat plate 251 spaced from end wall 252 of the slideway 230, and connected to the slideway by side walls 253. The flat plate 251 defines a slot or guideway 254 therein, that slot being of a width adapted to receive the body 144 of each gun's charge valve 138 in sliding relation therewith. The coupler plate 251 is spaced from the planar end face 252 of the slideway 230 a distance D equal to the thickness T of the adapter 140 plate carried by the hand gun 110. End 255 of the slot or guideway 254 in the coupler dap/
1067~7(~
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plate 251 serves ~o locate the gun's charcJe valve 138 in coaxial relation with loncJitudinal axis 232 oE the source's feed valve 207 when the charge valve's body 144 is sea-ted there-against, see Figure 4.
The molten adhesive 205 vessel, combined with a hand . gun 110, is pressurized by compressed air through structure illustrated in Figures 4 and 4a. When no hand gun 110 is being charged froln the vessel 205, the pressure is relieved ~¦from that vessel by use of the manual pressure relief valve ¦221. The vessel 205 is interconnected with a compressed air ¦source, not shown, through pressure line 249. ~ control valve ¦256 is interposed in the compressed air line 249, and is adapted to be activated by each hand gun's adapter 140 (as mounted to each hand gun's charge valve 138) when that adapter is fully seated within the feed valve's coupling 250. The control valve 256 is mounted on the slideway 230 in operative combination with the coupling 250 as illustrated in Figure 4a particularly.
¦The pressure line 249 exhausts into vessel 205 through port ¦¦257 adjacent the top edge of one of the vessel's side walls 1 258.
The control valve 256 for pressure line 249 includes a tubular body 259 threadedly received at the closed end of ¦ the coupling 250. The valve body 259 carries, in slideable relation therein, a stem 260 mounting a valve elemeht 261 on ¦one end thereof and extending into space or gap 262 between coupler platc 251 and the slideway's cnd Eace 252 at thc othor end 263 thereof. The stem 260 is maintained in alignment within the valve body by ribs 264. The air line 249 passes transversely , through the tubular body 259 relative to stem 260. In the non-active or closed attitude, valve elemellt 261 abuts rib . , '~ .
û6787~
. . . .
264 a5 SO urgcd by compression sprillcJ 2G5, ~hcrcby closin~ oEfthe vcss~l 205 ~rom ~lle com~res3cd air c;ourcc, i.~., thereby interrupting the compressed air line 249 at the control valve 256. The valve 261 is abutted against rlb 264 in that closed attitude by spring 265 as to maintain the valve in the closed attitude at all times unless otherwise activated.
In usej and when the hand gun's adapter 140 is inserted into the coupling 250 so as to place the hand gun's charge valve 138 in coaxial longitudinal axis 232 relation ith the vessel's feed valve 207, i.e., when the charge valve's body 144 is seated against bottom edge 255 of the slot 254 in coupler plate 251 as illustrated in Figure 4, the charge valve's adapter 140 engages the control valve's stem end 263 to displace the valve element 261 from blocked relation with the compressed air line 249, thereby opening the vessel's interior 220 to the compressed air source as illustrated in Figure 4a. This, in turn, permits the molten adhesive within vessel 205 to be pressurized, which pressure causes transfer of l molten adhesive through the vessel's feed valve 207 and the gun's charge valve 138 into the hand gun's storage chamber 117.
In other words, when the vessel 205 is pressurized that pressure overcomes the feed valve's compression spring 238 pressure to force the valve body 233 into O-ring 241 sealing relation with the gun's adapter's face 242, and also forces the ball 243 valve ff seat 244 in the valve body 233 to permit molten adhesive o flow through ~l~c Eecd valvc 207 as dcscribed morc Eully elow.
The molten adhesive vessel 205 of the first embodiment 01 is mounted on stand 206 by bolts 204. The floor 203 of the stand 206 is elevated substantially above a table tcp 202 .. ~26- ~
106~87~) or other surface on which the vessel 205 is supported, by vertical post 201 connected to foot 200 of the stand. The floor 203 of the stand 206 is maintained parallel to the foot 200 of the stand by a gusset 199 interposed therebetween and mounted to the side post 201. The stand's foot 200 may be bolted, as at 266,-to, for example, a table top or the like. The elevation of the vessel's floor 208 above the stand's foot 200 permits ready interengagement of the hand gun's charge valve 138 with the vessel's feed valve 207 as illustrated in Figures 1 and 4.
The second embodîment 100 of a hot melt source particularly adapted for use in combination with the hand gun structures of this invention is illustrated in U.S. Patent No. 3,827,603, issued August 6, 1974, and assigned to the assignee of this application.
This patent illustrates a pump and molten adhesive reservoir system that can be particularly adapted for use in connection with the system oE this invention. The pump is electrically controlled by an on/off switch to regulate flow of molten adhesive from the reservoir of the structure illustrated in that patent. One of the primary differences between this second embodiment lQ0 of a molten adhesive source and the first embodiment 101 described above is that the first embodiment is automatically activated when the hand gun 110 is fully seated or located in operative combination with feed valve 207. But the molten adhesive source 100 of the second embodiment must be manually activated by operating an on/off switch once a hand gun 10 or 90 is operationally connected with the charge valve 270 of the second embodiment.
The reservoir and pump structure shown in Patent No.
~67870 ,hould be able to orient the gun, and therefore the gun's noz~le into any spatial location desired so as to deposit molten adhesive in the exact location required on an assembly or sub-assembly to accomplish the desired bonding result in the easiest and most efficient manner. Therefore, and in the most preferred situation, an adhesive gun should be completely portable in the sense that it should not be connected with any feedstock supply source, or any power source, at all; this would allow the operator to manipulate - the gun into whatever spatial orientation is desired, no matter what the structural configuration of the workpiece, so as to achieve optimum results. However, and in the case of all hot melt adhesive gun structures known to the art, as far as we are aware, the gun must either be connected to a molten feedstock supply source by a feed hose or to an electric power source by a power cord or to both a feed hose and a power cord so orientation of the gun in that . manner desired by the operator is limited to the extent that the gun itself is encumbered by at least one hose or cord. Even with the adhesive gun so connected, it is desirable that the operator have as much freedom and use of the gun as is possible to facil~tate production efficiency and to prevent overtiring of the operator. In this connection, the flexiblity and weight of a power cord is usualIy substantially less burdensome than a hot melt feed hose, so that overtiring of the operator when only a power cord is interconnected with a hand gun is not anywhere near as great as when both a power cord and a hot melt feed hose are interconnected with the hand gu~
There are two basic systems for supplying molten adhesive to the discharge valve in a hand gun type applicator device. The first system requires an extruder type structure dap/
~L~6~7~
incorporated in the yun's barrel to translate, within the hand gun itself, solid feedstock (e.g., in pellet or siug form) into m~lten feedstock at the discharge valve. Such is accomplished by forcing the solid feedstock through a relatively high temp-erature heat exchanger in the gun's barrel, the force being provided by, e.g., a pneumatic motor supplied with air pressure through a power cord. An adhesive gun of this type is disclosed in U S. Patent No. 3,818,930, issued June 25, 1974, and assigned to the assignee of this application.
The second system of supplying molten adhesive feed-stock to the gun's discharge valve is to transmit the feedstock in molten form to the gun through a feed hose from a separate supply source. In this system the molten feedstock is translated from solid state (e.g., pellets, bulk, billet or chunk) to molten state at a separate location by a melter structure separate from the hand gun itself. ~he molten feedstock is then pumped from the melter structure to the hand gun through the gun's molten adhesive feed hose. Adhesive guns adapted to function from an - independent molten feedstock supply source in this manner are illustrated in U.S. Patent No. 3,543~968, issued December 1, 1970, and in U.S. Patent No. 4,006,845, issued February 8, 19i7, both patents being assigned to the assignee of this application.
Independent supply structures for melting and forwarding moltsn theremoplastic adhesive material through a feed hose to a separate hand gun structure are illustrated in U.S. Patent No. 3,815,788, issued June 11, 1974, and U.S. Patent No. 3,827,603, issued August 6, 1974, both patents being assigned to the assignee of this application.
In high speed assembly or production line situations, it is oftentimes desirable to use that type adhesive gun structure ~IL067~37~
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which is supplied with molten feedstock from a totally separate Ijhot melt adhesive source such as described in the second system i! above. This for the reason that this type system provides a ¦¦]arge and continuous supply of molten feedstock to the hand gun ~¦and, therefore, to the gun's operator. This precludes the neces- ¦
¦¦sity of continuously loading and reloading the gun with solid ,Ifeedstock by the operator during use, and the attendant time lost ¦
¦in connection therewith, such as required in the first system l¦described above. ~owever, and for hand guns used with the llsecond system, each of these hand guns must be connected directly !~ at all times to the separate molten adhesive source. This ,IConnection~ as previously mentioned, is maintained through lja hot melt feed hose, which may or may not be provided with ¦¦heater elements along the length thereof.
¦i The necessity of a hot melt feed hose in the second hot melt adhesive dispensing system presents several operating disadvantages, from a practical standpoint, in certain end use situations. First, and from an economic standpoint, each hand gun is generally supplied with its own molten adhesive 1! source. In other words, a separate and individual melter ~` ! structure remote from the gun is provided for each hand gun becaus the molten adhesive source must be connected directly at all times lwith the hand gun through the hot melt feed hose. Second, and l! from an operating standpoint, the hot melt feed hose itself adds ¦Isubstantial weight to and restraint on the hand-held gun as used ¦~or manipulated by the operator. In otller words, not only is thc ¦¦hot melt fecd hose itself vcry heavy (relative to an electric cord ¦¦usually also interconnected with the hand gun for purposes of l¦controllincJ the temperature of the heater block within the hand Igun), but the hot melt feed hose also imposes a substantial ' ' .
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06'7~37(~ .
restraint on the gun (relative to the electric cord) when the gun ~ust be manipulated into nooks and crannies of a workpiece by an operator. In this latter connection,~
manipulation of the hand gun into nooks and crannies by the operator, as dictated by the structural characteristics of the workpiece, lS impeded by interconnection with the hot melt feed hose and this tends to tire an operator's arm, thereby causing t~e operator to lose efficiency more quickly than would be the cas~ if no such hot melt feed hose were attached.
The difficulties and problems associated with prior art hand gun type hot melt adhesive applicators are overcome by the present invention which pro~ides a hand held gun for dispensing a molten fluid adhesive, the gun comprising a storage chamber within which a charge of molten fluid adhesive is stored, a nozzle through which the molten fluid adhesive is discharged onto a workpiece, a discharge valve for controlling discharge of the molten fluid adhesive through the nozzle, a pressurizing device within the gun, the pressurizing device maintaining that molten fluid adhesive within the storage - chamber under pressure during discharge of fluid adhesive from the gun, and a charge valve connected with the storage chamber, the charge valve permitting flow o~ a molten fluid adhesive charge one way through the valve into the storage chamber for charging and recharging the storage chamber, but preventing flow of fluid adhesive from the storage chamber out through the charge valve to atmosphere.
Other features and advantages of this invention will be more apparent from the following detailed description, taken .
10~i7870 - in.conjunction with the drawings, in which:
Figure 1 illustrates a hot melt adhesive dispensing system of the hand-held gun type in accord with the principles o~ this invention;
. Figure 2 is a cross-sectional view taken along the .. -- 7 --~)67137~
. I ~ . ., ¦¦ center longitudinal plane of a first elnbodimellt of a hand gun ¦¦ structured in accord with the principles of this invention; .
Figure 3 is a cross-sectional view taken along the center longitudinal plane of a second embodiment of a hand gun also structured in accord with the principles of this invention;
Figure 4 is a cross-sectional view of a first embodi-ment of a molten adhesive source in accord with the principles ¦ of this invention, that molten adhesive source being shown in operative combination with a cross-sectional view taken along the center longitudinal plane of a third embodiment of a hand gun also structured in accord with the principles of this invention; : . .
Figure 4~ is an enlarged view of the feed valve/charge valve structure illustrated in Figure 4;
~:~ , Figure 5 is a side view of a second embodiment of a molten adhesive source in accord with the principles of this . ~ invention; and ; ¦Figure 6 is a cross-sectional view taken along line 6-6 j of Figure 5.
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, . ' . ' ' ~067~7~
Th _ and lleld Gun .
A first cmbodi.mcnt.10 of a hand (Jun is i].lustratcd in Figure 2. As shown in that Figure, thc hand gun 10 includes a heater body 11 disposed within a housing 12. The housing 12 is configured to define a barrel portion 13 having longitudinal axis 14, and a storage chamber 15 portion having longitudinal axis 16, in a vaguely Y-shaped configuration. Likewise, the one-piece heater body 11 includes a barrel portion 17 having bore 18 coaxially disposed with the longitudinal axis 14 of the housing's barrel portion 13, and a feed portion 19 having bore . 20 coaxially disposed with the longitudinal axis 16 of the housing's storage chamber portion 15. The heater body's bores .
. ¦18, 20 are connected by connector bore 21. The storage chamber portion 15 of the housing is in the nature of a tubular shell 22 threadedly received as at 23 to the aft end of heater block.
, an O-ring 24 being inte~posed between that end of the shell ¦and the heater block to provide a seal tight relation therebetween ¦The gun's housing 12 is mounted in fixed relation with storage ¦¦chamber 25 defined by shell 22, and with heater body ll, in an ¦
~limmobile fashion through collar 2G frictionally embracing shell 22 and by other structure, not shown. ~ handle 27 structure, - ¦
illustrated in phantom lines, extends rearwardly from the aft ¦ end of the housing's barrel portion 13, the handle structure itself forming no part of the structure of this invention. Note ¦ particularly that the longitudinal axis 28 of the handle 27 is ¦disposed para].lel to the longitudinnl axis 16 of thc housing's ......... Istorage chamber 25.
The barrel portion 19 of the heater body 11 (which is fabricated of a heat conductive material) defines a bore 18 coaxially aligned with longitudinal axis 14 of the housing's ~ ~ , _g_~ ~ .
"'''~ ' . ~o6t7870 barrel 13 as prevjously mentioned. Tllis bore 18 is the dischargc bore for the molten adhesive. A nozzle 30 with longitudinal bore 31 is threaded, as at 32, into the interior of the dis-charge bore 18, i.e., into the heater body 11, at the discharge end of the gun 10. The heater body 11 also receives cartridge heaters, not shown, in bores, not shown, in the heater body that are parallel to axis 16 of the heater body. The temperature of the heater body 11 is controlled by thermostat 33 electrically ¦ connected to the electrical resistance hea-ter cartridges, not ¦ shown, and to a powersource, by wires, not shown.
¦ A discharge valve 34 is positioned within the discharge ¦bore 18 interiorly of the heater body 11. The discharge valve 34 includes a valve stem 35 and a valve head 36 fixed thereto, the stem being coaxially disposed within the discharge bore 18.
The valve head 36 is adapted to seat against valve seat 37 in sealing fashion, the valve seat heing press fit into the bore !¦ 18 against shoulder 38. A seal in the nature of a compressible ¦¦bellows 39 ls fixed at one end 40 to the valve stem adjacent the ¦¦valve head 36 and is fixed at the other end 41 to collar 42 ¦ ~the valve stem 35 is reciprocable throuyh the collar 42). The ¦collar 42 is held in fixed locati~n within the discharge bore ¦18 by virtue of being formed integral with retainer plate 43.
- ¦! That retainincl plate 43 is bolted by screws 44 to aft end face 45 of the heater body 11. The bellows 39 functions to allow longitudinal movement of the valve stem 35 while maintaining a . l scal to prevc~nt lenk;l~Je oE molten aclllesive Eeedstock Crom dis-charge bore 18 through the aEt end 45 of that bore into housing interior 46, thereby allowing valve head 36 and valve seat 37 to function as a discharge valve 34 as permittcd by the trigger 47 (describcd in detail below). The discharge valve 34 assembly ~ ' ' '.
1 ~067870 is hydraulically unl)llanaocl ;uc1) th;ll tl~c valvc hcad 36 and stem 35 wi].l movc rcarwardly duc to tllc hycll-aulic pressurc of molten feedstock in thc clischarge bore 18 (as vicwed in Figure 2) when the tri.gyer 47 is activated by an operator. This, of eourse, allows the molten adhesive feedstock to be discharged through the no~zle 30 onto a workpiece.
The gun's trigger 47 is adapted to coopcrate with eompression spring 50 loaded against a stop 51. End 52 of the valve stem 35 is slidingly received in bore 53 defined by the stop. The trigger 47 functions only to withdraw the stop 51 against the compression spring 50 bias, thereby allowing the diseharge valve 34 to open due to hydraulic pressure only of the molten feedstock (as previously described), and slidability of valve stem 35 in the stop's bore 53. The stop 51 is slidingly ¦reeeived in bracket 54, the bracket being formed integral with ¦the retainer plate 43. Compression spring 50 also bears against ¦the underside of that braeket's crown 55. Beeause of this ¦strueture, eompression spring S0 forces stop 51 continuously ¦against valve stem 35, thereby continuously biasing the valve ~head 36 toward the discharge valve 34 closed attitude (shown lin Figure 2) where the valve head is seated on the valve seat ¦37. An adjusting bolt 56 ~s threaded, as at 57, into the stop's shaft 58, that adjustment bolt extending through Eitting 59 in the aft end of the gun housing's barrel portion 13 into the interior of handle 27. By rotating bolt 56, the compression .
¦on spring 50 is increased or decrcasccl as dcsircd, tllexeby acljust~
¦ing the finger pressure required to operate the trigger 47.
¦ The trigger 47, which is carried within the gun's ¦handle 27, includes a thumb 48 that defines an elongated slot 49 through which the adjustment screw 56 passes, the adjustment Lo~7870 `
screw's head ~(~ causing Lho triggcr's thumb 48 to be captu~cd betwcen the screw's head and the lever Eace 60 at thc aft cnd of fitting 59. When the trigger 47 is pulled upwardly (as shown by directional arrow 61 in E'igure 2) by an operator's index finger, the trigger's thumb 48 .bears agai.nst lever face ¦ 60, thereby causing the s.top 51 to be drawn rearwardly against the bias of the compression spring 50 so that the discharge ~ . valve 34 can open in response to the hydraulic pressure of the : molten feedstock in discharge bore 18. When the operator releases the trigger 47,~ compression spring 50 moves the stop ; 51 into abutting contact with the valve stem's end 52, thereby closing the discharge valve 34 since the compression spring . pressure overcomes the molten feedstock's hydraulic pressure.
. ¦ The molten adhesive storage chamber 25 is provided .~ ¦with a pressurizing device therein, that device being in the form of a collapsible bladder 65. The bladder 65 is 1n the nature of a balloon positioned within the storage chamber 25, the collar 66 of the balloon extending out through port 67 at . the end of the chamber, and being restrained against the exterior .
20 end face 68 of that chamber by washer 69. Threaded fitting 70 is also located in the port 67, that fitting's flange 71 being ¦seated in recess 72 defined in the interior end face of the : ¦¦chamber end. Nut 73 cooperates with threaded section 74 of the fitting 70 to mount that fitting to the chamber's shell 22 . and, also, to restrain the bladder 65 in place within the chamber 25. Threaded sections 75, 76 of fitting 70 are adapted ... . to interconnect with a compressed air hose 77, as illustrated in Figure 1, for providing connection wi.th a compressed air source, not shown, to the interior oE thc bladder 65. Thc bladder 65, in responsc to the compressed air, is adapted to 7~ 70 I , . .
move between a fully collapsed attitude illus~rated in solid llines in ~igure 2 and a fully extended position illustrated ¦by phantom lines in Fiyure 2, the molten adhesive witilin the i storage chamber 25 being pressurized at the pressure of the ¦compressed ,air within the bladder 65 so as to provide the motive force for discharging adhesive through the gun's nozzle 30 in jresponse to opening of the discharge valve 34, as operated by the trigger 47 and as previously described. Pressure of the llcompressed air within bladder 65 remains constant at the air I,¦line 77 pressure no matter how much or how little molten adhesive ¦lis in storage chamber 25 since the bladder 65 is continuously 'open to that air line 77. On/off control of compres,sed air through hose 77 into bladder 65 is at a remote location, not shownli A normally open spring loaded check valve element is slidlingly disposed in bore 20 of barrel portion 19. Valve 4 element is retained inbore 20 by a lock pin 5 which is forced ¦ into an inters,ecting bore which is at a right angle to bore 20.
'~ Valve 4 has a conical head which cooperates with the I! tapered end wall 6 of barrel portion 19 to form a valve.
l' Valve 4 also has a reduced diameter portion or under-~cut 7 which mechanically cooperates with lock pin 5 to permit limited axial movement of valve element 4 but still retained in ,;bore 20. ~ compression spring is disposed in one end of bore jl20 and engages the tail end of valve 4 and urges valve 4 to the ,right against lock pin 5 and to an open position.
Eu~ L v;~lve cl~lllcll~ r~vc~ c ~L~
¦65 from being extruded into bore 20 as adhesive is forced from ¦chamber 25 by the bladder 6S.
11l, . .
~ 13-)6~7~90 Ii , . . . . .
charge valve 80 is connected with bore 18 of the ¦heater body 11 downstream of the dischargc valve's valve head i 36/valve seat 37. The charge valve 80 functions to interconnect hand gun 10 with a molten adhesive source 100, described in lldetail below, for purposes of charging the storage chamber 25 ¦¦with molten adhesive in a manner described in de~ail below.
The charge valve 80 inco~porates a cylindrical valve body 81 threadedly connected with heater body 11 as at 82, the body l¦defininy axis 83 that is disposed substantially normal to the 10 ¦!longitudinal bore 14 of the bore 18. A port 85 is provided ¦¦centrally of the valve body 81, that port opening into valve ! bore 86 defined by the valve body 81. The port 85 and valve bore 86 cooperate to define valve seat 87. The charge valve's seat 87 is adapted to receive a ball 88 valve element in seated relation thereon, the ball being spring closed at all times by compression spring 8~. The charge valve's compression spring ¦¦89 is maintained in compressive relation with the ball 88 valve element by spring retainer clip 90 which seats in groove 91 defined in the interior surface of the valve bore 86. The ,,charge valve 80, as is apparent from its structure, is a one--l¦way valve in the sense that it can only be opened to receive imolten adhesive flow into the heater body's bores 18, 2], 20 from ¦exterior of the gun 10. In other words, mol-ten adhesive flow ¦Ifrom the heater body's bore 18 out through port 85 of the charge jlvalve 80 is not possible as any pressure exerted on the ball 'l¦88 valve element from the interior of heater block'~ bore 18 lisimply serves to further press or force the ball 88 valve element ¦
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., . 1- .
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. 1 1067870 ~agains-t the valve seat 87. Conversely, and as is explained in greater detail below, the molten adhesive charged into the gun's storage chamber 25 from the molten adhes'ive source . lllO0 flows first through the charge valve 80 into valve bore : !¦86, then into discharge bore 18 of the heater body 11, there after through connector bore 21 and bore 20 in the heater body, and finally into the storage chamber 25 itself. Chary-ing flow of the molten adhesive into storage chamber 25 licollapses the bladder 65 into the solid line or substantially lifully charged attitude illustrated in Figure 2. The charge llvalve's body 81 also mounts a dovetailed adapter 84 on the ,exterior end face thereof, port 85 opening through the adapter .
84. The dovetailed adapter 84 is in the nature of a connector jlwhich permits the gun 10 to be interconnected with the molten ¦¦adhesive source 100 for charging the gun's storage chamber ¦¦25, as referred to above and described in detail below.
In use, and once the gun's storage chamber 25 has been fully charged with molten adhesive, high pressure air iis introduced into the bladder 65 through air fitting 70 and ¦i supply hose 77. Thereafter, and when the gun's trigger 47 i! is activated by an operator, the discharge valve 34 operates ¦¦as earlier described to permit molten adhesive to be dis-¦~charged from the gun's nozzle 30. The pressure within the . ¦ibladder 65 remains substantially constant no matter what the . ¦
- ~1 1.
1l -15- .
' ' ~ 1.
. l! I
1()6~7~'0 .' 11 . . '' ~
¦¦spatial a-t~itude of the bladdcr within the storage chamber 25, ¦¦i.e.l no matter how much molten hot melt adhesive remains in 'l¦or has been discharged from the storage chamber. The compressed I I air source remains at constant pressure, and that source is continuously and directly connected with the bladder 65.
Thus, even pressure is maintained on the molten hot melt ad- ¦
! hesive within the storage chamber 25 so as to force the adhes-; i¦ive out of the gun 10 at an even rate no matter what quantum ¦lof molten adhesive remains within that chamber until the last lof the molten adhesive has been discharged.
; Ii A second embodiment 78 of the hand held adhesive ¦gun, also in accord with the principles of this invention, ¦is illustrated in Figure 3. The reference numbers used in jlFigure 3 are identical to those used in Figure 2 Eor identical parts. The primary differences between the Figure 3 em~odi-ment and the Figure 2 embodiment, previously described, is in the structure of heat block 79 and the pressurizing device 92.
In other words, the Figure 3 hand gun 78 structure incorporates llthe same housing 12 structure, the same discharge valve 34 I'structure, the same handle 27 structure, the same nozzle 30 jlstructure, and the same charge valve 80 structure as with i jthe Figure 2 embodiment. -l In the second hand gun embodiment 78, the heater ¦Iblock 79 is oE a slightly difEerent structural conEiguration ¦Ithan that SllOWIl EO1' ~hc heater block 11 in ~hc Figurc 2 on~odilncnt Il , . ..
. ~ I
Il -15a-11 .
'I' . ., I
~ -- --G7~370 .` I . ' .
. ` ' - ' ' . ~lowever, and as with hea~cr block 11, tllc heater body 79.also has at lcast one heater cartridye, no~ shown, mounted therein.
The heater block 79 in the second embodiment 78 has a bore 9i . coaxial with the axis 16 of the storage chamber 25, w~slich bore 93 directly connects with the block's discharge bore 18, instead of interconnecting with that bore 18 through a connector bore 21 as in the case of the Fiyure 2 embodiment. rrhe heater block 79 in this second hand gun 78 embodiment is formed integral with a tubular casing 94 that extends rearwardly of the heater 10 - body 79 relative to the gun's nozzle 30. The tubular casing 94 defines the molten hot melt adhesive storage chamber 25 for this hand gun embodiment. The tubular casing 94 is closed at . its rearmost end by an end cap 95 threadedly engaged, as at 96, with the tubular casing.
The pressurizing device 92 of this hand gun 90 includes a cup-shaped piston 97 located within the tubular casing 94, that piston being illustrated in the fully retracted attitude in solid lines in Figure 3 and in the fully extended attitude . in phantom lines in Figure 3. The pressure wall 98 of piston 97 l abuts front end face 99 of chamber 25 when the chamber is empty.
The piston 9i is spring loaded by a compression spring 64 that ¦is seated against the piston's pressure wall 98 at one end and ¦
¦ abuts against end cap 95 at the other end. The pressure generated ¦by piston 97 against the molten adhesive within the storage ¦chamber 25 is, of course, caused by spring 64 pressure.
In us;o, tllc s,tora(Jc cl)a~ or 25 .i.~ ir-.;t ~ully cllaL-J~l ... with molten hot melt adhesive through charge valve 80 so that the piston 97 is fully retracted as illustrated in solid lincs in Figure 3 (thc rear face 103 of the piston abutti.ng against .
. ~ , ~ 1067~7(~
the interior face oE end car~ 95 to define that rearmost or fully retracted position). During charging through charge valve 80, the charging pressure of the molten adhesive must be sufficient to overcome spring ~, pressure so as to cause piston 91 to retrac from the phantom line to solid line position. Thereafter, and when the trigger q7 is activated by an operator, operation of the discharge valve 34 is as previously described in connection with the first embodiment. In this connection, pressure exerted on the mol-ten adhesive within the storage chamber 25 by piston 97 forces the molten hot melt adhesive out through the gun's nozzle ` 30.
A third embodiment 110 of a hand heId gun fabricated in accord with the principles of this invention is illustrated in Figures 4 and 4A. As shown in Figure 4, the third embodiment 110 includes a housing 111 having a barrel 112 portion and a handle 113 portion, the barrel portion defining longitudinal axis 114 and the handle portion defining longitudinal axis 115, those axes interconnecting at an acute angle as ¦ illustrated. The housing 111 incorporates the barrel 112 portion' ¦ and the handle 113 portion as a single integral part. This ¦ embodiment 110, as is apparent from Figure 4, therefore presents a housing more in the nature of a classic pistol configuration.
A one-pie-ce heater block 116 and storage chamber 117 structure, of a generally tubular geometry, is mounted within tile housing 111 coaxially with the longitudinal axis 114 of the gun's ¦ barrel 112 portion. This one-piecc structure incorporates the heatcr body 116 with longitudinal discharge bore 118, and the storage chamber 117 as defined by longitudinal casing 119, that chamber opening directly into discharge bore 118 at one end and being closed at the other end by end cap 120. The heator body 116 d storage chnmber ~11 eleme~t 1S ~lso provided:
, -]7-6787!~t with cartridge heaters, not shown, for maintaining a desired temperature level of that element 116, 119 so as to keep thc molten adhesive within the storage chamber in a molten state after same has been charged into the gun from a separate molten adhesive source 101. The cartridge he~ters are electrically connected with a thermostat 123 also mounted to that element 116, 119 for the purpose of sensing the temperature thereof, the cartridge heaters and thermostat being also electrically - connected with an electric power source in a manner well known to those skilled in the art.
The gun's discharge valve 122 is located in discharge bore 118 of the heater bbdy 116, a cross fitting 121 which forms the valve body of discharge valve 122, being threadedly received at one end as at 124 within the other end of discharge bore 118. The other end of the cross fitting 121 is threadedly received as at 125 in the gun's nozzle 126, that nozzle defining nozzle bore 127. A plunger shaped valve element 128 is coaxially received within the valve body's bore 129 as defined ¦by the cross fitting 121. The valve element 128 includes ¦head 130 adapted to seat against valve scat 131 defined at the forward face of the cross fitting 121. The stem 132 of the valve element 128 is provided with a flange 133 at that end opposite the head 130 end. A compression spring 134 is interposed between the forward face of that flange 133 and ledge 135 defined on the interior surface of bore 129 so as ¦to continuously bias tho valve's head 130 Loward tllc closcd ¦attitude as illustrated in Figure 4. Since the valve's head ¦130 is spring loadcd closed, any prcssure on the inner face of thc- valve's head exceeding the compression spriny 134 pressure will causc tlle valve to open, thereby permitting discharge of 11 ` ~06'7~37~
mol.ten adhesive from thc CJUn ~s storage chamhor 117 throu~Jh thc .
nozæle 126 onto a worlcpiece as doslred.
1~he charge valve 138 in the hand gun 110 is generally similar.to the charge valve ~0 in the Figures 2 and 3 embodi-: ment except that the charge valve axis 139 is normal to the ¦axis 114 of the storage.chamber 117. Further, the charge valve's adapter 140 is no-t dovetailed, i.e., is simply a f-lat, plate-shaped flange. ~s in the Figure 2 and 3 embodiments, 10 and 78, the charge valve 138 of the Figure 4 embodiment 110 incorporates a ball 141 valve element adapted to seat against valve seat 14~ defined in bore 143 of the valve body 144. The ball 141 valve element is spring 145 loaded against that seat . 142, the spring being trapped by retainer ring 146 seated in groove 147 on the interior face of the valve bore 143.
The pressurizing device for the hand gun 110 is an .
; air powered piston 150, the piston being cup-shaped in configu-ration. The piston 150 is slidingly received within the . cylindrical bore 151 that constitutes storage chamber 117.
. n O-ring 152 is interposed about the periphery of the piston adjacent the pressure face 153 thereof so as to mai.ntain a fl~id ti~ht seal between the piston and the storage chamber's wall 151. The piston 150 is retained within the storage chamber 117 by abutment against end cap 120 at one end (see . solid line position in Figure 4), and abutment against ledge 154 of the chamber at the other end (see phantom line position in Figurc ~).
. . The piston 150 is powered by pressurized air from a compressed air source, not shown, which is interconnccted Wit]
the hand gun 110 through compressed air feed hose 156. As 30 ~ strated in ~igure 4, the compressed air hose 15G interconnects 87~) wi-th toc 157 Eormed intcgr,ll wi~h the hcatcr bloc~ 116 and storage chamber casing 119, a thread~d fi~ting 158 and nut 159 being providcd for that purpose. Air bore 160 connects the compressed air feed hose 156 with the interior 161 of the cup-shaped piston 150, that bore including a section 162 milled out in the end cap 120 which permits air to be continuously fed from tha~ section 163 of the bore within the one-piece body ¦ 116, 119 continuously into the interior of the piston even when the piston abuts end cap 120.
A control valve 164 is interposed within that air bore 160, the control valve being connected with trigger 165 of the hand gun 110 so as to permit controlled operation of the gun by an operator as desired. The gun's trigger 165 is pivotally mounted by pin 166 to handle 113 of the gun. The control valve 164 includes stem 167 coaxially disposed in valve ,~ bore 168, the stem including a valve element 169 and a stop element 170. The stem 167 is spring 171 loaded into that attitude illustrated in Figure 4; in that a-ttitude the compressed air source is shut off from the piston 150 to establish the nonoperative attitude. The valve element 169 is positioned and maintained in this nonoperative or off attitude by stop 170 being seated against ledge 172 defined in the valve bore 168.
The exterior end 173 of the valve stem is simply slidingly contacted with surface 174 of the gun's trig~er 165.
In use, the third embodiment 110 of the hand gun is chargcd wi~l~ mo]~c~ ot molt adllcsivc EJ:OIII;I scpar;l~c nlol~cl~
adhesive source 101 with the control valve 164 structure in the nonuse or off attitude illustrated in Figure 4. ~s is particu-larly apparent fxom that Figure, tlle piston 150, which is disposed in the phantom line attitude after all molten adhesive ~ -20-....
: I 1~)67~37al within the storagc chamber l17 has been exl~au!iLed, is returned to thc solid line attitude as molten adllesive is recharc3ecl into the storage chamber. Any air trapped within the storage chamber 117 to the rear of the piston 150, i.e., within space 161, is exhausted back through the grooye 162 and bore 160 into the valve bore 168 behind the valve element 169 and out through exhaust port 163. In other words, exhaust port 163 permits the piston 150 to move rearwardly, as illustrated in Figure 4, ¦back into the solid line or completely charged attitude with ¦ little resistance as any air trapped within the storage chamber 117 exhausts through the exhaust port. When use of the gun 110 by an operator is desired, the trigger 165 is simply pulled, thereby moving the control valve element 169 to the right as illustrated in Figure 4 to admit compressed air into bore 160 and groove 162 behind piston lS0. The pressure thereby generated on the molten adhesive within chamber 117 by the piston 150 overcomes the pressure of compression spring 134. This forces the valve element 130 off valve seat 131 and permits molten ¦adhesive to exhaust through the gun's nozzle 126. When discharge of molten adhesive is to be stopped, the trigger 165 is simply released with the result that valve spring 134 closes the dis- ¦
charge valve 122. This opens the space 161 in storage chamber 117, i.e., the space behind the piston 150, to atmosphere through ¦the exhaust port 163, thereby eliminating high pressure on the molten adhesive within the storage chamber 117. This, in turn, permits the disc:har(Je valve's compression sprin(J 13~ to c]x>sc the discharge valve 122, thereby stoppincJ clischarcJc oE molten adhesive through the nozzle 126.
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l'he Molten ~dhes.~ve_Source ' A fi.rst cmbodi.mcnt 10]. oE tllc moltcn adllCsiVC sourcc adapted for use with the hand gun 110 illustrated in ~igures 4,4a is illustrated generally in Figure 1 and in detail in Figure 4. ~s shown in Figure 1, the hot melt source 101 includes a molten adhesive vessel 205 positioned on top of la stand 206. The vessel 205 itself is provided with a feed ¦valve 207 in the floor 208 thereof, the feed valve being prGvided.
. jwith structure, as described in detail below, which permits periodic and -temporary interconnection of the hand gun 110 therewith. The pressure vessel is surrounded by insulation walls 209, those insulation walls being protected from the environment by a sheet metal casing having side walls 210 as well as a cover wall 211. ' '.
The molten adhesive vessel 205 is closed at the top by a lid 212 structure. It is, of course, through opening . of the lid 212 that the vessel 205 may be charged with large ¦quantities of hot melt adhesive for purposes of maintaining ¦a ready supply of molten adhesive to the hand gun 110. The lid 212 structure comprises a frame 213 connected to the top edge ' 214 of the'vessel 205 by bolts 215. The frame 213 supports the lid 212, and the lid is pivotally mounted on axis 216 on the frame for opening and closing the vessel 205 to atmosphere .
through access opening 217. The lid 212 includes a catch 218 at one end thereof, the catch being adapted to interconnect with the framc 213 for mailltaining the li.d in a c].osed attitudc.
... he lid 212 also includes an O-ring 219 on the underside for sealing'the lid to the frame 213, thereby maintainincJ thc ressurized integrity oE the vessel's interi.or 220. ~ manually perable pressure relieE valve 221 is also providcd in the lid 212.
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~067870 1' ij .
¦ l'he pressurc rc].icf vai.ve 221 compriscs a valvc e].cmcnt 222 wi~h valvc hcad 223 on tllc bottom o a !;~CIII 224, ~hc valvo hcad being seated against the underside 225 o~ the lid with a seal ~ ¦being maintained through use of an O-ring 226. The valve head .1 ¦223 is spring loaded into sealed relation with the underside-of the lid by compression spring 227 interposed between the top side 228 of the lid and flange 229 at the top of the valve stem 224.
A feed valve 207, as previously mentioned, is incorporatT
ed into the floor 208 of the source vessel 205. The feed valve 207 includes a bore or tubular slideway formed integral with the vessel itself, that slideway defining a bore 230 having a longi-tudinal axis 232. The tubular slideway 230 carries the feed valve 207 in slideable or reciprocable relation therein. The . feed valve 207 includes valve body 233 of generally T-shaped cross section, that valve body 233 being comprised of tubular : section 234 and flange 235 at one end thereof. The valve body 233 and, hence, the valve 207, is slideable within the tubular . slideway 230 between an inner limit defined by ring 236 received in an annular groove on the interior surface of the slideway 230, , and seat 237 also defined on the.interior surface of the slideway ¦
¦ 230. In other words, and when in the fully closed attitude as ' ¦
shown in Figure 4a, the valve body 233 is seated against the . ¦r.ing 236, the valve body being continuously biased into that position by compress'ion spring 238 interposed between that valve body's flange 235 and ledge 239 defined in the slideway 230.
When in thc acti.ve or flow attitudc, as il].ustratcd i.n Fig. ~, thc travel limit of valve body 233 is defined by seat 237. A firstO-rir g 240 is rcceivcd in the periphery of the valve'body's flange 235 to 1~6787~
maintain a sealing relation between the interior 220 of the vessel 205 and atmosphere. A second 0-ring 241 is carried in the outer fa~e of the valve body's tubular section 234 for cooperation with the exterior face 242 of each hand gun's adapter 140 as described hereinafter in detail.
The feed valve 207, in addition to valve body 233, also includes a ball 243 valve element adapted to seat on seat 244 defined in bore 245 through that valve body 233. The ball 243 valve is spring loaded toward the valve closed or seated attitude, as illustrated in Figure 4A, by compression spring 246. The compressian spring 246 is retained in loaded relation with the ball 243 valve by ring 247 carried in a groove defined on the interior surface of the valve bore 245. Thus, and as illustrated in Figure 4A, with the feed valve 207 in the non-active attitude, the ball 243 valve is spring 246 loaded closed against seat 244 of the valve body 233~
and the valve body 233 is spring 238 loaded against ring 236 of the slideway 230.
A gun coupling 250 is formed integral with the exterior end of slideway 230, the coupling serving to interconnect the hand gun 110 with the vessel 205 when charging or recharging of the gun with molten adhesive is desired. The coupling 250 is in the nature of a flat plate 251 spaced from end wall 252 of the slideway 230, and connected to the slideway by side walls 253. The flat plate 251 defines a slot or guideway 254 therein, that slot being of a width adapted to receive the body 144 of each gun's charge valve 138 in sliding relation therewith. The coupler plate 251 is spaced from the planar end face 252 of the slideway 230 a distance D equal to the thickness T of the adapter 140 plate carried by the hand gun 110. End 255 of the slot or guideway 254 in the coupler dap/
1067~7(~
. 11 .. . . I
'~ , . ' . .' . I
plate 251 serves ~o locate the gun's charcJe valve 138 in coaxial relation with loncJitudinal axis 232 oE the source's feed valve 207 when the charge valve's body 144 is sea-ted there-against, see Figure 4.
The molten adhesive 205 vessel, combined with a hand . gun 110, is pressurized by compressed air through structure illustrated in Figures 4 and 4a. When no hand gun 110 is being charged froln the vessel 205, the pressure is relieved ~¦from that vessel by use of the manual pressure relief valve ¦221. The vessel 205 is interconnected with a compressed air ¦source, not shown, through pressure line 249. ~ control valve ¦256 is interposed in the compressed air line 249, and is adapted to be activated by each hand gun's adapter 140 (as mounted to each hand gun's charge valve 138) when that adapter is fully seated within the feed valve's coupling 250. The control valve 256 is mounted on the slideway 230 in operative combination with the coupling 250 as illustrated in Figure 4a particularly.
¦The pressure line 249 exhausts into vessel 205 through port ¦¦257 adjacent the top edge of one of the vessel's side walls 1 258.
The control valve 256 for pressure line 249 includes a tubular body 259 threadedly received at the closed end of ¦ the coupling 250. The valve body 259 carries, in slideable relation therein, a stem 260 mounting a valve elemeht 261 on ¦one end thereof and extending into space or gap 262 between coupler platc 251 and the slideway's cnd Eace 252 at thc othor end 263 thereof. The stem 260 is maintained in alignment within the valve body by ribs 264. The air line 249 passes transversely , through the tubular body 259 relative to stem 260. In the non-active or closed attitude, valve elemellt 261 abuts rib . , '~ .
û6787~
. . . .
264 a5 SO urgcd by compression sprillcJ 2G5, ~hcrcby closin~ oEfthe vcss~l 205 ~rom ~lle com~res3cd air c;ourcc, i.~., thereby interrupting the compressed air line 249 at the control valve 256. The valve 261 is abutted against rlb 264 in that closed attitude by spring 265 as to maintain the valve in the closed attitude at all times unless otherwise activated.
In usej and when the hand gun's adapter 140 is inserted into the coupling 250 so as to place the hand gun's charge valve 138 in coaxial longitudinal axis 232 relation ith the vessel's feed valve 207, i.e., when the charge valve's body 144 is seated against bottom edge 255 of the slot 254 in coupler plate 251 as illustrated in Figure 4, the charge valve's adapter 140 engages the control valve's stem end 263 to displace the valve element 261 from blocked relation with the compressed air line 249, thereby opening the vessel's interior 220 to the compressed air source as illustrated in Figure 4a. This, in turn, permits the molten adhesive within vessel 205 to be pressurized, which pressure causes transfer of l molten adhesive through the vessel's feed valve 207 and the gun's charge valve 138 into the hand gun's storage chamber 117.
In other words, when the vessel 205 is pressurized that pressure overcomes the feed valve's compression spring 238 pressure to force the valve body 233 into O-ring 241 sealing relation with the gun's adapter's face 242, and also forces the ball 243 valve ff seat 244 in the valve body 233 to permit molten adhesive o flow through ~l~c Eecd valvc 207 as dcscribed morc Eully elow.
The molten adhesive vessel 205 of the first embodiment 01 is mounted on stand 206 by bolts 204. The floor 203 of the stand 206 is elevated substantially above a table tcp 202 .. ~26- ~
106~87~) or other surface on which the vessel 205 is supported, by vertical post 201 connected to foot 200 of the stand. The floor 203 of the stand 206 is maintained parallel to the foot 200 of the stand by a gusset 199 interposed therebetween and mounted to the side post 201. The stand's foot 200 may be bolted, as at 266,-to, for example, a table top or the like. The elevation of the vessel's floor 208 above the stand's foot 200 permits ready interengagement of the hand gun's charge valve 138 with the vessel's feed valve 207 as illustrated in Figures 1 and 4.
The second embodîment 100 of a hot melt source particularly adapted for use in combination with the hand gun structures of this invention is illustrated in U.S. Patent No. 3,827,603, issued August 6, 1974, and assigned to the assignee of this application.
This patent illustrates a pump and molten adhesive reservoir system that can be particularly adapted for use in connection with the system oE this invention. The pump is electrically controlled by an on/off switch to regulate flow of molten adhesive from the reservoir of the structure illustrated in that patent. One of the primary differences between this second embodiment lQ0 of a molten adhesive source and the first embodiment 101 described above is that the first embodiment is automatically activated when the hand gun 110 is fully seated or located in operative combination with feed valve 207. But the molten adhesive source 100 of the second embodiment must be manually activated by operating an on/off switch once a hand gun 10 or 90 is operationally connected with the charge valve 270 of the second embodiment.
The reservoir and pump structure shown in Patent No.
3,827,603, as is illustrated diagrammatically at 100 in Figure S
- 27 ~
dap/
~L~167~370 '~1 . of this application, is uscd with a novcl focd valve 270 structurc as illustratcd in FicJurc 6 of ~hi.s application. ~s . shown therein, a slideway bloc~ 271 is mounted to the source's manifold block 272 by bolts 273, that block 271 defining an outer valve bore 274 and seat 269 for O-ring 268. The valve bore 274 is coaxially disposed with longitudinal axi.s 275 of feed bore 276 in the manifold block 272. The feed valve 270 includes a primary valve element 27? having an inner valve bore 278 therein, the primary valve element being slidably .i received in outer valve bore 274 defined in the slideway block 271. Flange 279 of the primary valve element 277 seats an O-ring 280 about the periphery thereof for purposes of . maintaining a sealing relation between the primary valve element !
. and the slideway block 271. The primary valve element 277 also defines a valve seat 281 for a valve head 282. The primary valve element 277 i.s movable within bore 274 between a non-active or closed attitude illustrated in solid lines in FicJure 6, and a fully open or charge attitude ~not shown) in which end face 283 abuts seat 284 defined in the valve bore 274. ¦
! The primary valve element 277 is continuously spring loaded by compression spring 285 toward that attitude illustrated in solid lines in Figure 6, the compression spring being seated ¦ at one end on the seat 284 of the vlave bore 274 and at the .othex end against the underside of the primary valve element's flange 279.
A sccondary valvc c].elllcnt 28G is slidably rcccived .. . within inner or center bore 278 of the primary valve element 277, the secondary valve element including a valve stem 287 that threadedly mounts the valve head 282 at one end thereof.
A sealing relat:ion is maintained betwcen primary 277 and secondary I
.. ! . , I ' . .
¦ 286 valve elements by O-ring 288 on thc cxtcrior periphery on the secondary valvc olcmcnt's stem 287. ~n illner borc 289 in the secondary valve element 286 interconnects with the inner bore 278 defined by the primary valve element 277 through cross bore 290 in thè secondary valve element. The secondary valve element 286 also includes an annular flange 291 at that end opposite the valve head 282, the annular flange being seatable against seat 292 defined in the valve bore 274 to define the closed or non-operative position of the feed valve 270 illustrated in solid lines in Figure 6. An O-ring 293 is received on the exterior face 294 of the secondary valve element 286 for coop-¦ eration with the exterior face 295 of a hand gun's adapter 84 (see Figures 2 and 3) as described in detail below. Note particularly, as illustrated in Figure 6, that when in the ¦ non-operative or closed attitude the exterior face 294 of the i secondary valve element 286 is withdrawn or recessed behind Ij the exterior face 296 of the slideway block 271. Flow of molten ! adhesive from the reservoir 100 out through the feed valve 270 I ¦ is through feed bore 276 into the valve bore 274, then into ¦ inner bore 278 through the gap between valve head 282 and i seat 281, then into inner bore 289 through cross bore 290, and I I then to discllarge.
¦ A coupling 301 in the-form of a coupler plate 302 ¦i~s mounted to the exterior face 296 of the slideway block 271 by the same bolts 273 that mount that block 271 to the hot melt unit's manifold block 272. The couplor plate 302 defincs a slot 303 thereill analoc~ous to sLot 25~ in thc coul)lor l~late 251 illustrated in Figures 4 and 4a. The slot 303 is of a width W equal to the diameter D of the charge valve's bo.dy 81 on that gun 10 or 90 with which same is adapted for use.
.. ...
1~ 1067~37(~
The coupler. pla~c 302 also Icfincs a dove~allcd passayeway 304 therein, thc slot 303 and passageway 304 bcing syrnmctrically disposed rclativc to the longitudinal axis Z75 of the fecd valve 270, Bottom edge 305 of the slot 303 cooperates with the exterior surface oE charge valve's body 81 on both gun 10 and 90 to stop and locate that gun's charge valve 80 in coaxial relation with feed valve axis 275. The dovetailed passageway 30~ is adapted to be used, of course, only with a dovetailed adapter 84 as shown on charge valve 80 of the guns 10 or 90 illustrated in Figures 2 and 3. ~ vent port 306 interconnects the bottom of the passageway 304 with atmosphere.
In use, and when the pump and reservoir 100 is activated by use of an on/off switch, not shown, pressurized molten adhesive is introduced into the valve body's bore 274 which forces the primary valve element 277 against seat 284, and which forces the secondary valve element 286 into sealing relation with the face 295 of the.adapter 84 on a hand gun's charging valve 80 when the gun is operationally connected to the feed valve 270 by coupler 301. The difference in travel I path length between primary 277 .and secon-lary 286 valve elements causes the valve head 282 to lift off seat 281 on the primary valve element 277, thereby permitting molten adhesive to flow ¦ into the secondary valve element's bore 289 and, thence, open ¦ ball 88 valve in the gun's charge valve 80 for introduction ¦ into the hand gun's storage chamber 25 as described in greater ¦ detail bclow.
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7~7~
11 , '.
llot Mclt ~dhosive l)ispollsin~l System Thc hot mc~lt adhesive disponsill(3 system oE this invention includos the hand held adhesive gun 10 or 90 or 110 jand the separate molten adhesive source 100 or 101. As ¦illustrated in each of the three embodiments of the hand held adhesive gun, each includes a charge valve 90, 138 disposed downstream of -the gun's nozzle 30, 126, that charye valve being communicable with the gun's heater body 11, llG and, thence, with the gun's storage chamber 25, 117. Each charge valve 80, 138 is of a one-way valve structure that, in effect, admits molten hot melt adhesive into the gun's storage chamber 25, 117 but prevents molten hot melt adhesive from exhausting through that valve structure, thereby limiting the discharge of molten adhesive from the gun's storage chamber through the gun's discharge valve 34, 122 as controlled by the gun's trigyer 47, 165. Special connector or coupler structure 2`50, 301 is provided on each source 100, 10i that cooperates with special adapter structure 84, 140 on each yun 10, 90, 110 to inter- ¦
¦connect each hand gun embodiment with each molten adhesive 1l source for providing each gun with a charge of molten adhesive.
¦¦Once that interconnection is achieved, and as the molten adhesive l source 100, 101 is suitably pressurized, the feed valve structure !
~207, 270 associated with that source is activated so as to move ¦a portion of that feed valve structure into sealing relation with the hand gun's charge valve structure 80, 138, thereby aiding in the prevention of leakage during transfer of molten adhesive from thc source into the hand gun's storage chambor 25, 117. This system permits a single molton adhosive source 100, 101, i.e., a single supply sourcc, to serve multiple hand guns 10, 90, 110, i.e., to serye a multiple nurnber of l .
I
` ! -31- ~ !
.. _- ..... ... ... ......
- - .
~L~67~7~
.. ' I .
.
.' . ` '. , - ' ' .
opera-tors. Further, the structural a3pects of the systcm permit the hand gun 10, 90, 110 to be easily connected and disconnected from the source 100, 101 simply by s].iding tho yun into a limit stop type coupler structure 250, 301 adapted to receive the hand gun's charge valve's adapter 84, 140. The hand gun 10, ~0, 110 structure itself is of light weight and is easy to manipulate.
More particularly, and in use, the first embodiment 10 of the hand gun illustrated in Figure 2 is adapted for use with the second embodiment 100 of the hot melt source illustrated ¦ in Figures 5 and 6. With the first embodiment gun's storage chamb .
er 25 empty, the hand gun is gripped by the handle and oriented . so that the charge valve's adapter plate 84 is inserted in passage-way 304 defined by the source's coupler plate 302 until the charge valve's body 81 bottoms out or seats against bottom edge 305 of ¦that plate's slot 303, thereby locating the charge valve's axis coaxially with the feed valve's axis 275 of the source 100. The passageway 304 is sized dimensionally, relative to the size of ¦
the gun~s adapter plate 84, so that the plate is in sliding re-lation therewith but in a close tolerance fit therewith as well.
Thereafter, the on/off switch of the source 100 is activated so that moltcn adhesive under pressure is fed through the manifold block's bore 276 into the valve body's bore 274 where the pressure of the adhesive initially overcomes compression spring 274 to force .
the primary valve element 277 against seat 284 in the valve bore ¦274. 'l'hc pressurc of the.adllcsivo also cau.scs tllo sccondary ¦valvo olomcnt 2~G to movo toward thc right as illu-;tratcd in i~ )67870 .
.. . - . ., FicJuro G unti]. O-rillg 293 i.s di.st)oscd in scal.ing re].a~ion with the extcri.or facc 295 of tlle gun's dovctailed adapter 8~, thereby providing a closed or sealed flow path between the source's manifold block 272 and the gun's storage chamber 25.
This relocation of the primary 277 and secondary 286 valve elements, in response to the pressurized molten adhesive, main-tains the valve head 282 in spaced reiation from the valve seat 281, thereby permitting molten adhesive to 1OW under pressure through the primary valve element's bore 278 into the secondary .
valve element's bore 289 against the ball 88 valve in the gun's charge valve B0. The pressurized molten adhesive also over- ¦
comes compression spring 89 pressure on the ball 88 valve, thereby . *ermitting ~low through the charge yalve's bore 86 into the heater : ¦ body's bores 18, 21, 20 and back into the storage chamber 25. As !
the gun's storagelchamber 25 fills, the bladder 65 is collapsed . ¦until the chamber is totally filled. After the gun's storage ¦chamber 25 has been filled, the.source lOO is depressurized, . land with the pressure released therefrom ~he source's feed .
¦ valve 270 closes. Closure of the eed valve 270 is efected l in response to compression spring 285 pressure forcing the .1 primary valve element 277 to the left as illustrated in FicJure 6; thereby seating valve head 282 on seat 281. The primary element continues its leftward motion, drawing the secondary valve element 286 therewith until the secondary valve element is seated on s~a~ 292. This removcs O-ri}lg 293 from sealing .. . relation witll thc gun adauter's face 29S, and thercby rcccsscs the fc~d valve 270 into bore 274. ~rhereafter~ the gun's adapter.
' .'.' . ~ 3.~ ` .
I . ' . '~
~67~376~
. 11 , .
34 is rcmovc(l from ~hc pa~ JCway 304 to cliscng.clc thc ~lun 10 from ~hc source 100, alld is ~hereaf~cr rcady Lor use. Usc oE
the hand gun 10 thereafter is as previously descri~ed.
The Figure 3 embodiment 90 of the hand gun is likewise adapted for use'with the molten aclhesive source 100, illustrated in Figures 5 and 6, in -the same manner as previously described for the Figure 2 embodiment 10. Use of that hand gun embodiment, ¦¦ after the storage chamber 25 thereof is filled, has been il previously described-l Use of the Figure 4 hand yun embodimen-t 110 is illustrated in Figures 1, 4 and 4A. As showll therein, and when the storage chamber 117 within the gun 110 is empty, the gun is oriented so as to be introduced into the passageway defined between coupler plate 251 and end face 252 of the source's feed valve 207. That introduction is illustrated in Figure 4A, and is fully accomplished when the valve body 144 seats against lower edge 255 of the slot 254 as illustrated in Figure'4. In this attitude the gun's adapter 140 has activated l control valve 256 by contact with the valve stem 260, thereby ~ removing spring 265 loaded valve element 261 from the air pressure line 249. This opens the pressure line 249 to vessel 205, pressure on the molten adhesive therein forcing the source's valve body 233 away from the non-operative attitude illustrated in Figure 4A toward the exposed face ' I 242 of the gun's adapter 140 and into sealing relationship therewith illustrated in Figure 4. This prcssurc on thc molLen ¦ adhesive also forces ball 243 valve off the seat 244 of the valve `body 233 against compression spring 246 to permit flow of pressuri~ed molten adhesive past the ball valve 243 against the gun' 5 char~e valve 133. The molten adhesive pressure _34. ' ' '~
~ 67~370 ¦ agaillst the CJUil~; charcJe va].ve 13B liEts l:ho ball l~il ofE its ¦seat 1~2 as wel.l, tllereby permitting intloc'iucti.on oE the molt~n adhesive into the heater body's bore 118 and thence into the storage chamber 117. This, of course, permits automatic filling of the gun's storage chamber 117 in response to coupling . of the hand gun's charge valve 138 in coaxial relation with the source's feed valve 207. Once the gun 110 is filled, it.is . removed from the coupler 250, thereby automatically closing the compressed air line 249 to the vessel 205; pressure on the vessel is released by manual pressure release valve 221.
Since no pressure is on the molten adhesive within the vessel 205 thereafter, compression spring 246 moves the ball 243 .
. valve against seat 244, and spring 238 .lifts valve body 233 away from the face 242 of the gun's adapter 140 to permit full : . removal thereof. Use of the gun 110, once recharged, is as : previously described.
: I Uaving described in c-letail the preferred embodiments ¦of our invention, what we desire to claim and protect by Letters . ¦¦Patent is:
._.~ .
- 27 ~
dap/
~L~167~370 '~1 . of this application, is uscd with a novcl focd valve 270 structurc as illustratcd in FicJurc 6 of ~hi.s application. ~s . shown therein, a slideway bloc~ 271 is mounted to the source's manifold block 272 by bolts 273, that block 271 defining an outer valve bore 274 and seat 269 for O-ring 268. The valve bore 274 is coaxially disposed with longitudinal axi.s 275 of feed bore 276 in the manifold block 272. The feed valve 270 includes a primary valve element 27? having an inner valve bore 278 therein, the primary valve element being slidably .i received in outer valve bore 274 defined in the slideway block 271. Flange 279 of the primary valve element 277 seats an O-ring 280 about the periphery thereof for purposes of . maintaining a sealing relation between the primary valve element !
. and the slideway block 271. The primary valve element 277 also defines a valve seat 281 for a valve head 282. The primary valve element 277 i.s movable within bore 274 between a non-active or closed attitude illustrated in solid lines in FicJure 6, and a fully open or charge attitude ~not shown) in which end face 283 abuts seat 284 defined in the valve bore 274. ¦
! The primary valve element 277 is continuously spring loaded by compression spring 285 toward that attitude illustrated in solid lines in Figure 6, the compression spring being seated ¦ at one end on the seat 284 of the vlave bore 274 and at the .othex end against the underside of the primary valve element's flange 279.
A sccondary valvc c].elllcnt 28G is slidably rcccived .. . within inner or center bore 278 of the primary valve element 277, the secondary valve element including a valve stem 287 that threadedly mounts the valve head 282 at one end thereof.
A sealing relat:ion is maintained betwcen primary 277 and secondary I
.. ! . , I ' . .
¦ 286 valve elements by O-ring 288 on thc cxtcrior periphery on the secondary valvc olcmcnt's stem 287. ~n illner borc 289 in the secondary valve element 286 interconnects with the inner bore 278 defined by the primary valve element 277 through cross bore 290 in thè secondary valve element. The secondary valve element 286 also includes an annular flange 291 at that end opposite the valve head 282, the annular flange being seatable against seat 292 defined in the valve bore 274 to define the closed or non-operative position of the feed valve 270 illustrated in solid lines in Figure 6. An O-ring 293 is received on the exterior face 294 of the secondary valve element 286 for coop-¦ eration with the exterior face 295 of a hand gun's adapter 84 (see Figures 2 and 3) as described in detail below. Note particularly, as illustrated in Figure 6, that when in the ¦ non-operative or closed attitude the exterior face 294 of the i secondary valve element 286 is withdrawn or recessed behind Ij the exterior face 296 of the slideway block 271. Flow of molten ! adhesive from the reservoir 100 out through the feed valve 270 I ¦ is through feed bore 276 into the valve bore 274, then into ¦ inner bore 278 through the gap between valve head 282 and i seat 281, then into inner bore 289 through cross bore 290, and I I then to discllarge.
¦ A coupling 301 in the-form of a coupler plate 302 ¦i~s mounted to the exterior face 296 of the slideway block 271 by the same bolts 273 that mount that block 271 to the hot melt unit's manifold block 272. The couplor plate 302 defincs a slot 303 thereill analoc~ous to sLot 25~ in thc coul)lor l~late 251 illustrated in Figures 4 and 4a. The slot 303 is of a width W equal to the diameter D of the charge valve's bo.dy 81 on that gun 10 or 90 with which same is adapted for use.
.. ...
1~ 1067~37(~
The coupler. pla~c 302 also Icfincs a dove~allcd passayeway 304 therein, thc slot 303 and passageway 304 bcing syrnmctrically disposed rclativc to the longitudinal axis Z75 of the fecd valve 270, Bottom edge 305 of the slot 303 cooperates with the exterior surface oE charge valve's body 81 on both gun 10 and 90 to stop and locate that gun's charge valve 80 in coaxial relation with feed valve axis 275. The dovetailed passageway 30~ is adapted to be used, of course, only with a dovetailed adapter 84 as shown on charge valve 80 of the guns 10 or 90 illustrated in Figures 2 and 3. ~ vent port 306 interconnects the bottom of the passageway 304 with atmosphere.
In use, and when the pump and reservoir 100 is activated by use of an on/off switch, not shown, pressurized molten adhesive is introduced into the valve body's bore 274 which forces the primary valve element 277 against seat 284, and which forces the secondary valve element 286 into sealing relation with the face 295 of the.adapter 84 on a hand gun's charging valve 80 when the gun is operationally connected to the feed valve 270 by coupler 301. The difference in travel I path length between primary 277 .and secon-lary 286 valve elements causes the valve head 282 to lift off seat 281 on the primary valve element 277, thereby permitting molten adhesive to flow ¦ into the secondary valve element's bore 289 and, thence, open ¦ ball 88 valve in the gun's charge valve 80 for introduction ¦ into the hand gun's storage chamber 25 as described in greater ¦ detail bclow.
., . .
.. _.. _ . . .
7~7~
11 , '.
llot Mclt ~dhosive l)ispollsin~l System Thc hot mc~lt adhesive disponsill(3 system oE this invention includos the hand held adhesive gun 10 or 90 or 110 jand the separate molten adhesive source 100 or 101. As ¦illustrated in each of the three embodiments of the hand held adhesive gun, each includes a charge valve 90, 138 disposed downstream of -the gun's nozzle 30, 126, that charye valve being communicable with the gun's heater body 11, llG and, thence, with the gun's storage chamber 25, 117. Each charge valve 80, 138 is of a one-way valve structure that, in effect, admits molten hot melt adhesive into the gun's storage chamber 25, 117 but prevents molten hot melt adhesive from exhausting through that valve structure, thereby limiting the discharge of molten adhesive from the gun's storage chamber through the gun's discharge valve 34, 122 as controlled by the gun's trigyer 47, 165. Special connector or coupler structure 2`50, 301 is provided on each source 100, 10i that cooperates with special adapter structure 84, 140 on each yun 10, 90, 110 to inter- ¦
¦connect each hand gun embodiment with each molten adhesive 1l source for providing each gun with a charge of molten adhesive.
¦¦Once that interconnection is achieved, and as the molten adhesive l source 100, 101 is suitably pressurized, the feed valve structure !
~207, 270 associated with that source is activated so as to move ¦a portion of that feed valve structure into sealing relation with the hand gun's charge valve structure 80, 138, thereby aiding in the prevention of leakage during transfer of molten adhesive from thc source into the hand gun's storage chambor 25, 117. This system permits a single molton adhosive source 100, 101, i.e., a single supply sourcc, to serve multiple hand guns 10, 90, 110, i.e., to serye a multiple nurnber of l .
I
` ! -31- ~ !
.. _- ..... ... ... ......
- - .
~L~67~7~
.. ' I .
.
.' . ` '. , - ' ' .
opera-tors. Further, the structural a3pects of the systcm permit the hand gun 10, 90, 110 to be easily connected and disconnected from the source 100, 101 simply by s].iding tho yun into a limit stop type coupler structure 250, 301 adapted to receive the hand gun's charge valve's adapter 84, 140. The hand gun 10, ~0, 110 structure itself is of light weight and is easy to manipulate.
More particularly, and in use, the first embodiment 10 of the hand gun illustrated in Figure 2 is adapted for use with the second embodiment 100 of the hot melt source illustrated ¦ in Figures 5 and 6. With the first embodiment gun's storage chamb .
er 25 empty, the hand gun is gripped by the handle and oriented . so that the charge valve's adapter plate 84 is inserted in passage-way 304 defined by the source's coupler plate 302 until the charge valve's body 81 bottoms out or seats against bottom edge 305 of ¦that plate's slot 303, thereby locating the charge valve's axis coaxially with the feed valve's axis 275 of the source 100. The passageway 304 is sized dimensionally, relative to the size of ¦
the gun~s adapter plate 84, so that the plate is in sliding re-lation therewith but in a close tolerance fit therewith as well.
Thereafter, the on/off switch of the source 100 is activated so that moltcn adhesive under pressure is fed through the manifold block's bore 276 into the valve body's bore 274 where the pressure of the adhesive initially overcomes compression spring 274 to force .
the primary valve element 277 against seat 284 in the valve bore ¦274. 'l'hc pressurc of the.adllcsivo also cau.scs tllo sccondary ¦valvo olomcnt 2~G to movo toward thc right as illu-;tratcd in i~ )67870 .
.. . - . ., FicJuro G unti]. O-rillg 293 i.s di.st)oscd in scal.ing re].a~ion with the extcri.or facc 295 of tlle gun's dovctailed adapter 8~, thereby providing a closed or sealed flow path between the source's manifold block 272 and the gun's storage chamber 25.
This relocation of the primary 277 and secondary 286 valve elements, in response to the pressurized molten adhesive, main-tains the valve head 282 in spaced reiation from the valve seat 281, thereby permitting molten adhesive to 1OW under pressure through the primary valve element's bore 278 into the secondary .
valve element's bore 289 against the ball 88 valve in the gun's charge valve B0. The pressurized molten adhesive also over- ¦
comes compression spring 89 pressure on the ball 88 valve, thereby . *ermitting ~low through the charge yalve's bore 86 into the heater : ¦ body's bores 18, 21, 20 and back into the storage chamber 25. As !
the gun's storagelchamber 25 fills, the bladder 65 is collapsed . ¦until the chamber is totally filled. After the gun's storage ¦chamber 25 has been filled, the.source lOO is depressurized, . land with the pressure released therefrom ~he source's feed .
¦ valve 270 closes. Closure of the eed valve 270 is efected l in response to compression spring 285 pressure forcing the .1 primary valve element 277 to the left as illustrated in FicJure 6; thereby seating valve head 282 on seat 281. The primary element continues its leftward motion, drawing the secondary valve element 286 therewith until the secondary valve element is seated on s~a~ 292. This removcs O-ri}lg 293 from sealing .. . relation witll thc gun adauter's face 29S, and thercby rcccsscs the fc~d valve 270 into bore 274. ~rhereafter~ the gun's adapter.
' .'.' . ~ 3.~ ` .
I . ' . '~
~67~376~
. 11 , .
34 is rcmovc(l from ~hc pa~ JCway 304 to cliscng.clc thc ~lun 10 from ~hc source 100, alld is ~hereaf~cr rcady Lor use. Usc oE
the hand gun 10 thereafter is as previously descri~ed.
The Figure 3 embodiment 90 of the hand gun is likewise adapted for use'with the molten aclhesive source 100, illustrated in Figures 5 and 6, in -the same manner as previously described for the Figure 2 embodiment 10. Use of that hand gun embodiment, ¦¦ after the storage chamber 25 thereof is filled, has been il previously described-l Use of the Figure 4 hand yun embodimen-t 110 is illustrated in Figures 1, 4 and 4A. As showll therein, and when the storage chamber 117 within the gun 110 is empty, the gun is oriented so as to be introduced into the passageway defined between coupler plate 251 and end face 252 of the source's feed valve 207. That introduction is illustrated in Figure 4A, and is fully accomplished when the valve body 144 seats against lower edge 255 of the slot 254 as illustrated in Figure'4. In this attitude the gun's adapter 140 has activated l control valve 256 by contact with the valve stem 260, thereby ~ removing spring 265 loaded valve element 261 from the air pressure line 249. This opens the pressure line 249 to vessel 205, pressure on the molten adhesive therein forcing the source's valve body 233 away from the non-operative attitude illustrated in Figure 4A toward the exposed face ' I 242 of the gun's adapter 140 and into sealing relationship therewith illustrated in Figure 4. This prcssurc on thc molLen ¦ adhesive also forces ball 243 valve off the seat 244 of the valve `body 233 against compression spring 246 to permit flow of pressuri~ed molten adhesive past the ball valve 243 against the gun' 5 char~e valve 133. The molten adhesive pressure _34. ' ' '~
~ 67~370 ¦ agaillst the CJUil~; charcJe va].ve 13B liEts l:ho ball l~il ofE its ¦seat 1~2 as wel.l, tllereby permitting intloc'iucti.on oE the molt~n adhesive into the heater body's bore 118 and thence into the storage chamber 117. This, of course, permits automatic filling of the gun's storage chamber 117 in response to coupling . of the hand gun's charge valve 138 in coaxial relation with the source's feed valve 207. Once the gun 110 is filled, it.is . removed from the coupler 250, thereby automatically closing the compressed air line 249 to the vessel 205; pressure on the vessel is released by manual pressure release valve 221.
Since no pressure is on the molten adhesive within the vessel 205 thereafter, compression spring 246 moves the ball 243 .
. valve against seat 244, and spring 238 .lifts valve body 233 away from the face 242 of the gun's adapter 140 to permit full : . removal thereof. Use of the gun 110, once recharged, is as : previously described.
: I Uaving described in c-letail the preferred embodiments ¦of our invention, what we desire to claim and protect by Letters . ¦¦Patent is:
._.~ .
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS-
1. A hand held gun for dispensing a molten fluid adhesive, said gun comprising a storage chamber within which a charge of molten fluid adhesive is stored, a nozzle through which said molten fluid adhesive is discharged onto a workpiece, a discharge valve for controlling discharge of the molten fluid adhesive through said nozzle, a pressurizing device within said gun, said pressurizing device maintaining that molten fluid adhesive within said storage chamber under pressure during discharge of fluid adhesive from said gun, and a charge valve connected with said storage chamber, said charge valve permitting flow of a molten fluid adhesive charge one way through said valve into said storage chamber or charging and recharging said storage chamber, but preventing flow of fluid adhesive from said storage chamber out through said charge valve to atmosphere.
2. A hand gun as set forth in claim 1, said charge valve comprising a valve body mounted to said gun, said valve body defining a valve seat, a ball valve adapted to be received on said valve seat, and a compression spring normally biasing said ball valve onto said valve seat, thereby normally closing said charge valve.
3. A hand gun as set forth in claim 1, said gun further comprising adapter structure mounted on said gun, said adapter structure permitting said gun to be connected with a fluid adhesive source for charging said storage chamber through said one-way charge valve.
4. A hand gun as set forth in claim 1, said pressurizing device being selected from one of a fluid powered piston and a fluid filled bladder.
5. A hand gun as set forth in claim 4, said pressurizing device further comprising a fluid line connecting said pressurizing device with a fluid pressure source, and a control valve operably connected with said fluid line and mounted within said gun, said control valve being actuatable by the gun's operator to admit fluid pressure for activating said pressurizing device.
6. A hand gun as set forth in claim 5, said control valve opening said fluid line to atmosphere when said control valve is not activated, thereby exhausting fluid pressure from said pressurizing device.
7. A hand gun as set forth in claim 1, said pressurizing device being in the form of a spring loaded piston.
8. A hand held gun for dispensing a molten fluid adhesive, said gun comprising a storage chamber within which a charge of molten fluid adhesive is stored, a nozzle through which said molten fluid adhesive is discharged onto a workpiece, a discharge valve for controlling discharge of the molten fluid adhesive through said nozzle, a pressurizing device within said gun, said pressurizing device maintaining that molten fluid adhesive within said storage chamber under pressure during discharge of fluid adhesive from said gun, said discharge valve being operatively responsive to said adhesive under pressure in said storage chamber to discharge said adhesive from said gun, and a charge valve connected with said storage chamber, said charge valve permitting flow of a molten fluid adhesive charge one way through said valve into said storage chamber for charging and recharging said storage chamber, but preventing flow of fluid adhesive from said storage chamber out through said charge valve to atmosphere.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA321,325A CA1067870A (en) | 1977-01-26 | 1979-02-13 | Hot melt adhesive applicator of the hand held gun type |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/762,530 US4144913A (en) | 1977-01-26 | 1977-01-26 | Hot melt adhesive dispensing system of the hand held gun type |
| CA286,452A CA1058122A (en) | 1977-01-26 | 1977-09-09 | Hot melt adhesive dispensing system of the hand held gun type |
| CA321,325A CA1067870A (en) | 1977-01-26 | 1979-02-13 | Hot melt adhesive applicator of the hand held gun type |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1067870A true CA1067870A (en) | 1979-12-11 |
Family
ID=27165279
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA321,325A Expired CA1067870A (en) | 1977-01-26 | 1979-02-13 | Hot melt adhesive applicator of the hand held gun type |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1067870A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022109689A1 (en) | 2020-11-26 | 2022-06-02 | Souza Silvano Baptista De | Industrial thermoplastic adhesive applicator |
-
1979
- 1979-02-13 CA CA321,325A patent/CA1067870A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022109689A1 (en) | 2020-11-26 | 2022-06-02 | Souza Silvano Baptista De | Industrial thermoplastic adhesive applicator |
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