US2956509A

US2956509A - Fluid dispensing pumps

Info

Publication number: US2956509A
Application number: US760042A
Authority: US
Inventors: Rex C Cooprider; Douglas F Corsette
Original assignee: Drackett Co
Current assignee: Drackett Co
Priority date: 1958-09-09
Filing date: 1958-09-09
Publication date: 1960-10-18
Anticipated expiration: 1977-10-18
Also published as: GB906875A; FR1236720A; DE1266647B; CH362033A; BE582489A; NL243140A; NL106608C; ES251955A1

Description

1950 R. c. COOPRIDER ETAL 2,956,509

FLUID DISPENSING PUMPS 2 Sheets-Sheet 1 Filed Sept. 9, 1958 INVENTOR c. (M

. k .3 W W W w, \\\\\\\\A\\\\\\\\\\\\\\\\\\A i 1 /I/ 1/14 w k 3 43 1| 2 w 41 l E \\\\Y\\ 7 ATTORNEY 1960 R. c. COOPRIDER ETAL 2,956,509

FLUID DISPENSING PUMPS 2 Sheets-Sheet 2 Filed Sept. 9, 1958 INVENTOR f 'ow.

l/d/m, 4, 4am Law ATTORNEY Unitfid S ttes Patent FLUID DISPENSING PUMPS Rex C. "Cooprider, Downey, and Douglas F. Corsette, Los Angeles, Calif., assignors to The Drackett Company, Cincinnati, Ohio, a corporation of Ohio Filed Sept. 9, 1958, Ser. No. 760,042

20 Claims. (Cl. 103-178) This invention relates to new and improved fluid dispensing pumps of the class in which the pump plunger is immobilized in a predetermined position for packing and shipping purposes to avoid inadvertent actuation and discharge of the liquid contents of a container to which such a pump may be applied.

In liquid dispensing pumps adapted for application to and sale with containers for various commercially dispensed liquids, it has been heretofore known, as exemplified by the Lohse US. Patent 2,119,884, to utilize a protective cover for immobilizing the pump plunger in a predetermined depressed condition and also for trapping and retaining any liquid that may be inadvertently discharged from the pump. It has been found, however, that in practice a very appreciable amount of liquid may be discharged into such a protective cap due to inversion of the container and/or expansion of its contents. In

such case, the liquid may escape either through the usual liquid discharge passage of the plunger and the plunger head or between the plunger and the barrel in which it works.

It is, accordingly, a primary object of the present invention to provide an improved form of fluid dispensing pump having means for retaining the plunger in immobilized position and including additional means rendered operative by immobilization of the plunger for closing oif the plunger discharge passage and at the same time providing a fluid seal or block preventing egress of the liquid between the pump plunger and its associated barrel.

The preferred means for retaining the plunger thus immobilized is a protective hold-down cap which is threaded or otherwise secured to the container over the plunger head to depress the plunger to its immobilized position against spring pressure.

The invention further contemplates that the discharge opening or orifice of the plunger head will be surrounded by a frusto-conical sealing surface for cooperation with a similar frusto-conical interior surface of the protective cap whereby to prevent discharge of fluid from the plunger head into the cap incident to application of the cap and depression of the plunger to its immobilized position, as will as subsequent thereto.

It is a further incidental object to utilize such cooperating conical surfaces on the cap and plunger head respectively for automatically centering and locating the threaded skirt of the cap for cooperation with the threaded hold-down collar of the pump, the plunger and plunger head being rotatable about an axis coincident with said threaded collar to facilitate turning of the cap onto the collar.

A still further object of the invention is to provide the cap and the threaded collar or other portion on which it is received with cooperating sealing means. In particular, such sealing means may comprise an upwardly axially opening annular groove in the threaded collar and an integral sealing ring guided by the cap for jamming reception in said groove. With such arrangement, the cap may be formed of a somewhat flexible 2,956,509 Patented Oct. 18, 1960 resilient plastic, such as polyethylene, to attain an improved sealing function by its said sealing ring and such ring will further function to resist radial stretching of the cap skirt with consequent slippage of the threads during application of the cap by automatic machinery. In other words, this well-recognized difficulty inherent in threaded resilient caps is overcome by the present invention.

The foregoing as well as other incidental objects and advantages are all attained by the embodiments of the invention illustrated in the accompanying drawings in which:

Figure 1 represents an axial sectional view through a liquid dispensing pump of the invention and the threaded container cap to which it is applied, the intake or suction tube of the pump being shown but fragmentarily. In this view, the pump is shown with the plunger in its immobilized position and with the protective cap applied;

Figure 2 is a view of the pump structure shown in Figure 1, but with the protective cap removed and the pump plunger raised to operative position;

Figures 3 and 4 respectively are fragmentary sectional views taken in the same plane as Figures 1 and 2 and showing modified forms of plunger seals;

Figure 5 is a view similar to Figure 1, showing a slightly modified form of pump structure;

Figure 6 is a detail elevational view of the upper end portion of the pump plunger and plunger head as seen from the right in Figure 2;

Figure 7 is a section on the line 77 of Figure 5; and

Figure 8 is a section on the line 8-8 of Figure 5.

Referring now in detail to the accompanying drawings, and considering first the form of the invention illustrated in Figures 1 and 2, these figures illustrate the invention as embodied in a liquid dispensing pump, which in this instance is mounted in a usual threaded metal container cap for application to a bottle, can or other container to dispense the liquid contents thereof in a known manner. The pump comprises a stationary pump barrel 10, which may conveniently be molded or cast from a substantially rigid material such as vinyl plastic. The pump barrel 10 is of hollow tubular construction so that its interior defines a pump cylinder 11 and it will be seen that the barrel at its upper end is centered in and opens through a circular central opening 13 within the container cap 12. The particular manner in which the barrel is so mounte will be more fully described hereinafter.

Depending from the lower end of the barrel is a suction tube 14, which may be of plastic or other usual material. It will be understood that the lower end of such tube, which is broken away in the present drawings, will depend into the liquid within the container to a point closely adjacent to the bottom of the container whereby the liquid contents may be withdrawn and dispensed through the pump structure of the invention. The upper end of the tube 14 is received and frictionally or otherwise retained in a depending sleeve portion 16 integral with the pump barrel.

Also formed integrally with and communicating with the interior of the pump barrel at its lower end is a foot valve cage or housing 1 8 formed with an inclined annular valve seat 20 for cooperation with a foot valve element exemplified by the ball valve 22. It will be noted that the inwardly projecting valve seat portion 20 has a lower surface abutting against and thereby serving to position the upper end of the suction tube 14. The ball valve 22 may, if desired, be guided in its seating and unseating movement by a plurality of guide ribs 24 and its unseating movement is preferably limited by overlying inwardly projecting retainers ordetents 26. These retainers have their inner ends disposed about a circle of very slightly smaller diameter than that of the ball valve 22. How

ever, the plastic vinyl or other material from which the pump barrel is formed has sufiicient inherent resiliency so that it may be expanded sufiiciently to permit forcing the ball 22 downwardly past these retainers into the valve cage 18, during assembly of these parts.

Disposed for reciprocation within the pump barrel is a generally tubular plunger 28, which also may be formed of vinyl or other plastic material. It will be noted that the upper end of this plunger projects upwardly through the open upper end of the barrel 11 and above the container cap 12, where it carries a cap-like plunger discharge head 29.

At its lower end the plunger carries a piston consisting essentially of an inverted cup having downwardly and outwardly flaring skirt 30 in snug sliding engagement with the inner cylinder wall 11 of the pump barrel. In the embodiment shown, the piston 30 includes an upper sleeve extension 32 which is press-fitted into the lower end of the plunger or otherwise retained therein. Preferably, the several parts of the piston are integrally constructed of resilient material such as polyethylene plastic, whereby the lower edges of the piston skirt 30 may tend to resiliently expand into fluid-tight engagement with the inner wall 11 of the barrel and thereby function more efficiently.

At its lower end, the piston 32 carries a downward extension or probe 34, which, in this embodiment, is of downwardly opening tubular construction, the arrangement being such that a passage 36 extends completely through the piston from the lower end of the probe upwardly into communication with the tubular interior of the plunger 28 to provide a discharge passage portion connecting with the tube 14 through the intermediary of the foot valve 18.

For the purpose of raising theplunger 28 on its upstroke, there is provided a coil spring 38 disposed concentrically about the probe 34 under compression between the piston and the lower end of the cylinder within the pump barrel. An upwardly presented annular shoulder 39 on the plunger is disposed for abutting engagement with the wiper ring 73, more fully described hereinafter, to limit the upward stroke of the plunger.

In order that such fluid as may escape upwardly past the piston 30 may be returned into the container, there is provided a usual breather passage or passages 40 through the side of the barrel just below the horizontal web of the container cap 12 and its associated sealing structure. Such port or ports 40 establish communication between the interior of the container and the interior of the pump barrel above the piston to permit return flow of the fluid, and also permit air from the container to flow into and from the barrel above piston 30, thus preventing an air lock such as might interfere with the plunger reciprocation.

Adjacent its upper end, the plunger 28 is provided with an additional valve seat 41 on which is seated a ball check valve 42 arranged to permit upward flow of fluid from the plunger head. The plunger discharge head 29 is shown as being in form of an inverted cup-like member having its depending skirt receiving and enclosing the open upper end of the plunger tube 28. The closed upper end 46 of the plunger discharge head is formed as a finger piece of suitable shape to permit actuation of the pump by repeatedly depressing it against the resilient force of its spring 38 and subsequently removing the finger pressure to permit the spring to return the plunger to its raised position. Internally the plunger head is formed with a depending stop 52 to limit unseating movement of ball 42.

-It will be noted that when the plunger is fully depressed and in its immobilized position, as shown in Figure l, the probe 34 at the lower end of the plunger will engage and force the ball valve 22 against its seat 20 and the ball valve thus will coact with both the seat 20 and'the' free end of the probe 34 toclose ofi'both' against the passageof liquid.

The lower end of the plunger head 29 terminates externally of the plunger tube 28 in an annular stealing ring or skirt 48, the lower outer periphery or lip of which constitutes a sealing surface which is adapted for engagement and cooperation with an annular sealing surface 76 concentrically surrounding and spaced from the upper end of the pump barrel for preventing escape of fluid upwardly between the pump barrel and plunger, such as might otherwise occur, for instance, in the event the pump and its container are inverted or partially inverted, and the fluid contents of the container thus permitted to flow through the breather ports 40 into the space between the plunger and pump barrel. If desired, the sealing surface or periphery 49a of the plunger skirt may be formed parallel to the conical sealing surface 76, as in the modification of Figure 3, for flush wedging engagement between said surfaces. Or, if desired, and as shown in Figure 4, the peripheral sealing surface 49b may be formed as a knife edge for yielding line engagement with the surface 76.

It will be seen that on the upstroke of the plunger and plunger head the ball valve 42 will remain seated to apply suction, drawing liquid upwardly through the tube 14, the ball valve 22 being thereby unscated to permit passage of such liquid into the plunger tube 28. Then, as the plunger and plunger head are depressed, the wall valve 22 will reseat to prevent return flow of the liquid and the ball valve 42 will be opened to permit upward flow of the liquid into the plunger head 29 and thence outwardly through the discharge port or opening 54 in the side wall of the plunger head. While the discharge port 54 may communicate directly with the atmosphere, in the present embodiment it is shown as delivering the fluid into a spray nozzle structure for ejection in the form of a spray. To this end there is provided an annular recess 56 around the outer end of this discharge opening or port, said recess being defined by an annular radiallyprojecting wall 57, having its radially projected periphery 57' disposed on the surface of an imaginary cone to provide a sealing surface for cooperation with the conical interior of the protective cap as hereinafter described. Pressed into and frictionally retained or cemented within the annular recess 56 is a spray disc 58 having a spray discharge orifice 62, which receives fluid from the discharge passage 54 through usual tangential whirl passages 59 and an annular distributing passage 60.

Reverting now to the connection between the pump barrel 10 and container cap 12, such connection is defined in the preferred embodiment by an annular plastic member 64 cemented or otherwise secured around the upper end of the pump barrel for disposition beneath the horizontal web of the container cap and for clamping between said cap and the upper end or lip of the container neck on which the cap is to be applied. A suitable gasket 66 may be applied over the under-face of the member 64- for sealing engagement with the bottleneck or lip. Formed integrally with the member 64 is an upstanding annular wall 68 which projects upwardly through the central cap opening 13 for connection to the annular collar or adapter member 70, being preferably received and frictionally retained or cemented in a downwardly pre sented annular groove 72 in the collar 70, so that the cap 12 is effectively clamped between

members

70 and 64. The lower end of the collar may conveniently support the wiper ring 73 hereinbcfore referred to for sliding wiping engagement with the plunger tube 28 and for abutting engagement with the shoulder 39 of the plunger tube to limit the upward movement of the plunger. The inner wall 76 of the collar above the wiper ring 73 preferably converges downwardly in the form of a conical sealing surface spaced from the plunger tube for reception of and sealing engagement with the depending annular sealing skirt 48 of the plunger head. The skirt 48 and plunger head areboth preferably formed. integrally of a. resilient plastic such as polyethylene and the collar 70 is preferably formed of a substantially rigid material such as vinyl plastic. The annular outer wall 80 of the collar is formed externally with screw threads 82 for cooperation with internal screw threads 84 on the depending inner wall portion of the protective cap 86. It will be seen that the cap 86 is disposed over the upper end of the plunger and plunger head and that its upper end engages the finger piece 46 to depress the plunger head and plunger to immobilized position as shown in Figure 1 when the cap 86 is threaded tightly onto the collar 70.

It will be apparent that frictional engagement between the skirt 48 and surface 76 may be relied upon, at least temporarily, to maintain the plunger in its depressed immobilized and sealed condition, even in the absence of the protective hold-down cap 86.

In order to effect a liquid tight sealing engagement between the cap 86 and the collar 70, the collar is formed with an upwardly presented groove 88 inwardly of its threaded outer wall 80 for reception of a depending annular sealing ring 90 on the cap. The dimensions of the groove and sealing ring are so related that the sealing ring 90 preferably makes a jamming fit into the groove 88.

It is preferred that the cap 86 be of resilient material in order that its conical interior sealing surface 92 may form a fluid tight sealing engagement with the conical peripheral surface 57' of the spray head and also so that its sealing ring 90 may form a yielding fluid tight fit within the groove 88. Where the cap is thus formed of resilient plastic, however, it is subject to the usual and known difliculty that excessive tightening of the cap, as by automatic capping mechanism, may tend to expand the lower edge of the cap skirt so that the threads 84 of the cap will override and become disengaged from the threads 82 on the collar. However, the depending ring or skirt 90, in addition to performing its sealing function, will resist such expansion tendency and thus adapt the resilient material caps for eflicient application by automatic capping mechanism.

For the purpose of automatically centering the protective cap 86 and guiding its threaded skirt accurately onto the threads of the collar 70, there is provided on the plunger head a radially projected boss 94, the radially outer end of which lies on a common cone with sealing surface 57' and cooperates with the projecting conical periphery 57 to engage the conical inner surface of the cap and center same coaxially with respect to the plunger and the collar. Moreover, the plunger and plunger head are both rotatable together with respect to the barrel and container cap 12 and will thus facilitate threading of the protective cap 86 onto the collar 70.

In the operation of the embodiment just described, it

container cap 12 and the protective cap 86 may be preassembled as a unit as in Figure 1 and thereafter applied to a bottle or other liquid container in obvious manner. In such event the ball 22 of the foot valve will be seated by engagement with the lower end of the tubular probe 34 and thus will prevent upward movement of any of the container contents past the valve seat or into the plunger. While possibly liquid may be permitted to enter the space between the plunger and its barrel through port or ports After the pump has been used, it will be seen that a certain amount of residual liquid will tend to remain in the hollow plunger barrel, and when this plunger is then depressed incident to application of the protective cap 86, this will tend to expel such residual liquid outwardly from the discharge head 29. However, it will be noted that, immediately upon application of the cap 86 over the spray head, the cooperation between the conical sealing surfaces 92 and 57,is rendered operative to resist such liquid discharge, and such cooperation is in fact improved bythe pressureexerted on the capin thus depressing it.

7 Moreover, the conical surface 57' and the boss 94 will coact with the conical inner surface 92 of the cap tocenter the latter, and therotatably disposed plunger accurately guides the threaded skirt of the cap onto the threaded collar 70, while permitting free rotation of the cap during its application to the collar.

Because ofthe axial disposition of sealing surface 76, it will be apparent that this surface will coact with the skirt or ring 48 to provide an effective seal for preventing leakage between the pump plunger and barrel throughout a substantial range of axial positioning of these parts, thereby permitting substantial manufacturing tolerances. Thus the seals 4876 and the seal provided by cooperation between the plunger and foot valve 18, will effectively prevent leakage, both between the plunger and barrel and through the plunger, in the depressed and immobilized position of the plunger. Moreover, such position may be maintained either through the protective cap 86 or through the frictional action of the seals 48-76 as heretofore mentioned.

In the form of the invention shown in Figure 5, the structure and function are identical to those heretofore described,'except as to the arrangement of the plunger piston and probe and the cooperation of these parts with will be apparent that the pump structure, the threaded 40 incident to inversion of the container, expansion of its contents, or leakage past the piston 30, the sealing engagement of the plunger head sealing ring 48 with the inner conical surface 76 of the collar 70 will normally prevent accidental escape of the fluid beyond this point. the ring 48 should be imperfect, then any fluid which escapes will nevertheless be maintained and confined in the protective cap 86 by the action of the seal 90. Similarly, the cooperation between the conical surfaces 92 and 58' of the protective cap and plunger head respectively will normally prevent escape of fluid from the plunger interior, though if any leakage should occur, it also would be contained within the cap 86.

In the event, however, that the seal provided by the foot valve. Accordingly, parts which are identical to those in the structure heretofore described are identified by similar reference characters, while modified parts or elements are herein identified by distinctive reference characters. Thus, in the modification of Figure 5, the plunger piston'30' consists basically of the downwardly flaring skirt of resilient plastic material, as heretofore, and includes an annular collar 36' by which it is supported in the lower end of the plunger tube 28. In this modification, however, the probe 34 is closed at its lower end and is surrounded by and includes a flaring resilient piston skirt 33 for snug fluid tight reception in the upper portion of the valve cage -18' in the depressed position of the valve plunger. Above the piston skirt 33 the probe 34 is hollow and is provided with one or more outwardly opening ports 35, so that when the piston skirt or plug 33 is withdrawn upwardly from the valve cage and into the relatively greater diameter pump barrel, the fluid is free to pass upwardly around the plug 33 and into the plunger barrel through the ports 35 incident to reciprocation of the plunger. In this, as well as in the preceding embodiment, it is apparent that the probes 34-34 coact with the foot valve, though in somewhat different manners, to arrest the upward flow of the fluid from the tube 14 when the valve plunger is fully depressed. In addition, in each of these modifications the probes 34 and 34' may be used during assembly of the foot valve to force the valve element or ball 22 downwardly into its cage past the detainers or detents 26 or 26'.

It will be appreciated that reference herein to a vertical disposition of the pump and of its principal parts, and to upper and lower locations and positions of component parts, is employed merely for convenience in describing and claim-ing the structure embodying the invention. While the pump normally occupies a generally upright position, it is, of course, usable when held in various other positions.

In this application, we have shown and described only the preferred embodiment of our invention and a simple modification thereof, in order to illustrate the best mode presently known to 'us of carrying out our invention. However, We realize that the invention is capable of other and different embodiments and its several details may be altered in various respects, although without departing from our invention. Accordingly, the draw.- ings-and description herein are to be construed. as merely illustrative in nature and not as restrictive.

Having thus d'escribedour invention, we claim:

1. A liquid dispensing pump comprising a generally vertical cylindrical barrel, an annular collar secured concentrically around the upper end of said barrel, a plunger reciprocally disposed in said barrel and projecting from the upper end of said barrel, the upper end of said plunger constituting a discharge head and having a liquid passage opening therethrough to define a discharge port, spring means coacting between said barrel and said plunger for urging the plunger upwardly from the barrel, a foot valve in the lower end of said barrel for permitting upward flow of liquid into said barrel, while preventing downward flow of said liquid and a probe carried at the lower end of said plunger for closing said valve in a predetermined position at the lowermost extremity of the reciprocating movement of said plunger, in combination with annular sealing surfaces formed on said collar and said plunger respectively, externally of the plunger for operative sealing engagement in said predetermined position of the plunger, to prevent upward leakage of liquid between the barrel and plunger, said liquid passage extending from said discharge port downwardly through said plunger and its said probe for normal communication with and control by said foot valve.

2. The liquid dispensing pump of claim 1, wherein said foot valve comprises a valve ball and a cylindrical valve cage confining said valve ball and of smaller diameter than the interior of said pump barrel and said plunger, and normally communicating at its upper end with the interior of said barrel, said plunger including a piston snugly reciprocally received in said pump barrel above said probe, said probe carrying a plug at its lower end for reception in said valve cage, said passage extending downwardly through said piston and opening between said piston and said plug.

3. A liquid dispensing pump as defined in claim 2, wherein said foot valve includes a valve ball operatively disposed in said valve cage, said cage having an inwardly projecting retainer above said valve ball for limiting the unseating movement thereof, and said probe depending to a sufficient extent in the said predetermined position of the plunger to press said valve ball from above to beneath said retainer for assembly purposes, said valve cage being formed of a material having suific-ient elasticity to permit the displacement of said retainer incident to assembly of the valve ball.

4. A liquid dispensing pump as defined in claim 1, including means on said plunger for selectively securing said plunger in its said predetermined position of reciprocation.

5. A liquid dispensing pump as defined in claim 4, wherein said means comprises a cap having a threaded skirt, and threads on said collar for cooperation with said threaded skirt.

6. A liquid pump as defined in claim 1, wherein one of said annular sealing surfaces extends and converges downwardly for jamming frictional engagement with the other of said annular sealing surfaces, sufficiently to frictionally maintain the plunger in said predetermined position.

7. The combination defined in claim 6, wherein said one sealing surface is formed on the said collar for concentric reception of the sealing surface carried by the plunger discharge head, said discharge head carrying a depending-downwardly andoutward-lyflaring resilient ery defining the said sealing surface of the discharge head.

8. The combination defined in claim 7 in which said outwardly flaring periphery is formed with a downwardly diverging conical surface for flush sealing wedging engagement with said one sealing surface. 7

9. A liquid dispensing pump as defined in claim 1, wherein said foot valve includes a valve cage communicating at its upper end with said pump barrel, and a valve ball movable downwardly in said cage to close said valve, said probe depending from the plunger to such extent as to engage and maintain the valve ball in valve closing position in said predetermined position of the plunger.

10. A liquid dispensing pump as defined in claim 9, wherein said liquid passage. opens through said probe in position to be covered and closed by engagement of the probe with the valve ball.

11. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar .-a discharge head having a discharge orifice for fluid, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, a check valve associated with said barrel to prevent downward movement of fluid therein, said plunger being forced to provide a discharge passage extending therethrough and communicating with said discharge orifice, a protective cap dimensioned to embrace said discharge head, said cap having a skirt for engagement with the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, coacting sealing surfaces on said plunger and collar, said sealing surfaces being engaged when said cap is threaded on said collar to seal said barrel to prevent leakage externally of said plunger, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage internally of said plunger, said last named means comprising a sealing ring surrounding said discharge orifice and having a contour conforming with the contour of the interior surface of said cap and positioned for sealing engagement with said cap in the depressed and immobilized position of said plunger, and coacting sealing surfaces on said cap and collar to contain within said cap liquid escaping from a defective seal either externally or internally of said plunger.

12. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head having a discharge orifice for fluid, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, a check valve associated with said barrel to prevent downward movement of fluid therein, said plunger being formed to provide a discharge passage extending therethrough and communicating with said discharge orifice, a protective cap dimensioned to embrace said discharge head, said cap having a skirt threaded for engagement with the'threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, coacting sealing surfaces on said plunger and collar, said sealing surfaces being engaged when said cap is threaded on said collar to seal said barrel to prevent leakage externally of said plunger, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage internally of said plunger, said last named means comprising a sealing ring surrounding said discharge orifice and a contour conforming with the contour of the interior surface of said cap and positioned for sealing engagement with said cap'in the depressed and immobilized position of said plunger, said plunger having means for engaging said check valvevandretainingthe same in closed position when said plunger is depressed and immobilized, and

aeeasos coacting sealing surfaces on said cap and collar to contain within said cap liquid escaping from a defective seal either externally or internally of'said plunger.

13. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, valve means associated with said barrel and plunger to prevent downward movement of fluid therein, said plunger being formed to provide a discharge passage extending therethrough and communicating with said discharge head, a protective cap dimensioned to embrace saidd-ischarge head, said cap having a skirt threaded for engagement with the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, coacting sealing surfaces on said plunger and collar, said sealing surfaces being engaged when said cap is threaded on said collar to prevent-leakage from surrounding said discharge orifice and having a contour conforming with the contour of the interior surface of said cap and-positioned for sealing engagement with said cap in the depressed and immobilized position of said plunger, and coacting sealing surfaces on said cap and collar, said last named surfaces being engaged when said cap is threaded on said collar.

14. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, valve means associated with said barrel and plunger to prevent downward movement of fluid therein, said plunger being formed to provide a discharge passage extending therethrough and communicating with said discharge head, a protective cap dimensioned to embrace said discharge head, said cap having a skirt threaded for engagement with the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, coacting sealing surfaces on said plunger and collar, said sealing surfaces being engaged when said cap is threaded on said collar to seal said barrel to prevent leakage externally of said plunger, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage internally of said plunger, and coacting sealing surfaces on said cap and collar, said last named surfaces being engaged when said cap is threaded on said collar and comprising a depending concentric annular flange on said cap, said collar being formed to provide a concentric annular groove dimensioned to receive said flange with a snug fit.

15. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, valve means associated with said barrel and plunger to prevent downward movement of fluid therein, said plunger being formed to provide a discharge passage extending therethrough and communieating with said discharge head, a protective cap dimensioned to embrace said discharge head, said cap having a skirt threaded for engagement with the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, said discharge passage opening radially through said discharge head, said head beingformed to provide a sealing surface defining a portion of a downwardly diverging cone surrounding said opening, the conical axis of said sealing surface being coincident with the axis of the threads on said collar, said cap being formed internally with a sealing surface of similar conical configuration, whereby turning of the cap onto said collar eflects sealing engagement between said sealing surfaces.

16. A fluid dispensing pump comprising a generally vertical cylindrical pump barrel having at one end thereof a collar having threads thereon, a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, valve means seating in said barrel below said plunger to prevent downward movement of fluid in said barrel, said plunger being formed to pro vide a discharge passage extending therethrough and communicating with said discharge head, a protective cap dimensioned to embrace said discharge head, said cap having a skirt threaded for engagement with the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said spring means, coac,tin g sealing surfaces on said plunger and collar, said sealingsurfaces being engaged when said cap is threaded on said collar to prevent leakage from said barrel externally of saidplunger, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage from saidbarrel intern-allyof said plunger, said last named means including a probe at the lower end of said plunger forming a continuation of said discharge passage, said probe being formed to provide a seat engaging said valve means to hold the latter in the seated position in said barrel when said plunger is depressed and immobilized, whereby said valve means blocks both said barrel and said discharge passage, and coacting sealing surfaces on said cap and collar to contain within said cap liquid escaping from a defective seal either internally or externally of said plunger.

17. A fluid dispensing pump comprising a generally vertical cylindrical pump barrel, a plunger reciprocally disposed in said barrel and having at its upper end a discharge head, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, valve means seating in said barrel below said plunger to prevent downward movement of fluid in said barrel, said plunger being formed to provide a discharge passage extending therethrough and communicating with said discharge head, means acting between said plunger and said barrel to hold said plunger in a depressed and immobilized position against the action of said spring means, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage from said barrel internally of said plunger, said last named means including a probe at the lower end of said plunger forming a continuation of said discharge passage, said probe being formed to provide a seat engaging said valve means to hold the latter in the seated position in said barrel when said plunger is depressed and immobilized, whereby said valve means blocks both said barrel and said discharge passage, and coacting sealing surfaces on said cap and collar to contain within said cap liquid escaping from a defective seal either internally or externally of said plunger.

18. In a fluid dispensing pump, the combination with a generally vertical cylindrical pump barrel having at its upper end a collar having threads thereon, of a plunger reciprocally disposed in said barrel and having at its upper end and above said collar a discharge head having a dis charge orifice for fluid, spring means acting between said barrel and plunger for urging said plunger upwardly in said barrel, a check valve associated with said barrel to prevent downward movement of fluid therein, said plunger being formed to provide a discharge passage extending 11 therethrough and communicating with said discharge orifice, a protective cap dimensioned to embrace said discharge head, said cap having a skirt'threaded for engagement with, the threads on said collar to hold said plunger in a depressed and immobilized position against the action of said. spring means, coacting sealing surfaces on said plunger and collar, said sealing surfaces being engaged when said cap is threaded on said collar to seal said barrel to prevent leakage externally of said plunger, means operable when said plunger is depressed and immobilized to seal said discharge passage to prevent leakage internally of said plunger, said last named means comprising coacting sealing surfaces relatively displaced into engagement when said cap is threaded on said collar to block flow of liquid through the discharge pamage and hence to said orifice, and coacting sealing surfaces on said cap and collar to contain within said cap liquid escaping from a defective seal either externally or internally of said plunger, the coacting sealing surfaces of each of said seals being angularly disposed with respect to the axis of the plunger, whereby pressure is applied between said surfaces when said cap is threaded down on the collar.

19. A fluid dispensing pump as claimed in claim 18 in which said means operable to seal said discharge passage comprises a probe carried by said plunger and engaging said check valve on depression of said plunger to hold said valve in seated position.

20. A fluid. dispensing pump as defined in claim 18, wherein said fluid discharge passage opens radially through said discharge head, said head including a conical downwardly diverging sealing surface surrounding said opening,

aesaso'o 12 a v the conical axis of said conical sealing surface being coincident with the axis of said threads, on said cap and said collar respectively, said cap being formed internally with a similar conical sealing surface, whereby turning of'the cap onto said collar will automatically interengage' the said conical sealing surfaces, said discharge head having on its diametrically opposite sides from its said sealing surface a radially projecting boss, the outer end of which lies on a common cone with said sealing surface of the said head to coact with said last mentioned sealingsurface for centering said cap relative to said discharge head and for positioning the threaded skirt thereof concentrically to the threads around said collar, said plunger and its a discharge head being rotatable in said barrel about an axis coincident with the generatrix of said threads for facilitating the application of said cap to said threaded collar.

References Cited in the file of this patent UNITED STATES PATENTS 1,486,600 Nuhring Mar. 11, 1924 2,024,570 Fischman Dec. 17, 1935 2,119,884 Lohse June 7, 1938 2,586,687 Mellon -n Feb. 19, 1952 2,657,834 Bacheller Nov. 3, 1953' 2,684,182 Gey July 20, 1954 2,870,943 Scoggin Jan. 27, 1959 FOREIGN PATENTS 256,416 Switzerland Feb; 16, 1949