ADHESIVE DISPENSING PUMP CONTROL SYSTEM AND PUMP

Abstract: An adhesive dispensing pump control system for automatically changing the flow rate of adhesive materials (15) being dispensed onto a workpiece (10) with an improved adhesive pump (14) in conformance with changes in movement of an automatically controlled adhesive dispensing nozzle (11) used to apply adhesive materials automatically onto the surface of a workpiece (10) in accordance with a predetermined pattern. The adhesive or other mastic dispensing pump control system operates to maintain substantially constant pressure across the dispensing pump (14) thereby making the system relatively insensitive to changes in viscosity of the adhesive (15) being dispensed and allowing adhesives to be dispensed at relatively high pressures.

Description: ADHESIVΞ DISPENSING PUMP CONTROL SYSTEM AND PUMP FIELD OF INVENTION The invention described in this application relates to a new and improved control system for a variable speed dispensing pump and to an improved pump therefor for pumping adhesive materials which may have a wide range of viscosities. Particularly, the invention relates to a control system for automatically controlling a controllable, variaole spaed, gear pump which is capaole of pumping adhesive materials that may be highly viscose and whose viscosity may vary widely with changes in temperature. The adhesive may also oe abrasive in nature. The automatic adhesive dispensing pump control system and improved adhesive dispensing pump can oe employed synchronously with a rooot or other automatically controlled adhesive dispensing nozzle drive system used to apply a predesigned pattern of adhesive around the surface. of a worκρiace efficiently and within predefined strict physical specifications. BACKGROUND OF INVENTION Rooot controlled adhesive dispensing systems must be capaole of responding to commands from a rooot or other similar control equipment so as to accomplish flow of a controlled amount of adhesive at particular points in the path of travel of an automatically positioned dispensing nozzle for the adhesive. A dispensing system without precise con rol of the flow of a highly viscous adhesive at particular points in tne craval of tne adhesive dispensing nozzle (such as might oe supplied by oali vaive arrangeuient, for example) restricts the concrolled adhesive dispenser co dispensing adaesiva oa a workplace at only one speed. If che automatically controlled (positioned and activated) dispensing aozzle ia such aa arrangement changes ies j aJ ac some poiac ia ies craval ovar cna worrpiao-., taaa cae- ispensed υaad of adhesive is uneven. Consequently, .-.itn suca arraage anc, taa maximum dispensing speed is limited co the minimum spaei α wnion ύ a automatically controlled nozzla can craversa corners and otner similar quick cnangas in direction. This is crue even though caa autom ically controlled nozzle is designed to travel faster in straight lines. Siuca the fiow race of cna aunasive oeiag dispensed is preset oy a oull vaive or otaer arrangement fj tne siowes. spaed (i.a. ar αaα corners) at waicn taa automatically controlled dispensing aoszia travels, taa aa« rasuit of moving faster would oa co reduce taa si__a of Λ-_ adaasive O._ ΛJ. oaia dispea≤ed waica is uaaccaptaoia in assamo_.y oparatiαas. Two prior αpproαeaas aava sαgyas ad to solve cnis proolam. The first uses a metared snot tacaaiqua waica employs α piston and cylinder αrrangameat and cna second usas a variaole orifice co _,o_ j.3 'c flow rate at particular points ia taa travel of aa automatically controlled dispensing no-.-_.ie. jlaichar αpproαcn aαs oe_ sacisfactory. To overcome tais prooiam, cna present invention has o _aa devised. SUMMARY Je 1 II7V5I.TIOI. Taa present invention utilizes a specially αasigaed gear pump to displace nigaiy viscous and BAD ORIGINAL so etimes aorasive adhesive materials. Gear pumps are commonly used for fluid pumping applications such as the pumping of oil, water and other low viscosity liquids. The adhesive gear pump employed in practicing the present invention nas a-ri specifically designed for very high viscosity adhesives such as epoxies. These adhesives are sensitive to temperature and tne pump used in dispensing sucn adnesivas cannot cause curing of cci- epo_jy adnesive during operation. Additionally, the pump used in tne invention has oean found reiiaole in tna presence of nighly viscous adnesives wnica also are very aorasive in nature. The pump is capable of withstanding nigh pressures of c e ordar of 1500 to 2000 pounds per square incn gauge at ootn its input and output. According " co tne invencion, a pump having tne aoova-discussad cnaractarisciαs is employed to supply adhesive under pressure to d. ~ adhesive dispensing control system wnicn caa chaaga the output flow of adnesive tnrough a nozzle so as to conform it co the speed oz movement of an automatically coatroI__ed (positioned) adnesive dispensing nozzle. This novel system can provide fast flow rates to an adhesive oeiag dispensed wnile tne dispensing aozzia is oeiag traced along straight lines. Th n at sharp corners wnere tne automatically controlled dispensing nozzle must slow dowa, tne flow rate through the dispensing aozzia is decreased ia synchronization witn the cnαnge ia positioning speed of tne nozzle. This approach allows tna average speed of tne rooot to increase and provides suostantial operating advantages in factory environments. In a typical application, α production rate using the invention was increased oy 25- over tnαt of Known prior art BAD ORIQI NAL adhesive dispensing arrangements. A second significant object of the invention is co provide required flow rates for nigh viscous adhesive in an environment of changing temperatures. Adhesives are known to change their viscosity witn changes ia amoient temperature. In ύ.«. oaii valve a__ampιa oriafly discussed aoove, an increase in temperature would actually increase the flow rate due co tne raαuced viscosity of the ddnasiva. Taa gear pump approach provided oy tne present invention dispenses a particular amount of adnesive for aacn revolution of tne gear pump rotors. .-Jhiia there may oe some leakage (flow-oy) tnrougn the pump, sucn leakage is minimal and the αdaasiva gear pump provided oy tne invention provides relatively coasi≤tant flow control over plus or minus 50% cnαagas in viscosity due to temperature cnanges. In practicing the iavantion, an adhesive dispensing pump control system is provided for automatically changing tne flow rate of adhesives oaing dispensed onto a worspiece in conformance with cuangas in movement of an automatically dd-icrollod adnesive dispensing .nozzle used to apply u predesigned pattern of aanesiva around the surface , a ./or pieee. The improved dispensing pump system comprises _.Λ adnesive dispensing pump aαv ag tne features dascrioed oej.ow for supplying adnesive material to a dispensing nozzle mounted on .id ..idvad oy a-i automatically controlled dispensing machine (sucn -._• a rooot) over a preprogrammed path of ...ovement to tnareoy dispense the adhesive in a predetermined pattern O CO the wor-.piecs. The άdnasive dispensing pump is driven oy a variaoia spaed electro servo drive motor that in turn is coatroileu o ^. servo drive electronic motor BAD ORIGINAL controller coupled to and controlling tne speed of the servo drive motor. The automatically controlled dispensing machine includes a programmaola control computer for controlling tne movejTient of tna adnesive dispensing aozzia in tracing out tne predesigned pattern of adhesive o ing dispensed. The servo drive electronic motor controller for tae adhesive pump motor also is controlled ^ caa control computer of tne ' automatically controlled dispensing machine in conjunction with the movement of tne adhesive dispensing nozzle wnereυy c _ speed of the adhesive pump is synchronized wi n che path of movement of n.- adnesive dispensing nozzle. The adnesive pump employed in the n.ov-1 adhesive dispensing pump control system comprises a pump housing defining pump cavity aaviag at least oaa inlet port and one outlet port. otataole pump impellers (prater oly intar eshing gear pump rotors) are supported within tne pump cavity for physically pumping adhesive supplied thereto through the -inlet port to the outlet port at a flow rate dependent upon tne rotαtioaa. speed of tne pump impellers. Tne pomp impe lers are secured to o.ii _i rotαtaoi-e ./xtn pump s k s wnicn are rotataoiy supported in snaft oeαriags secured witnin the pump housing. Sea__ing means are disposed around tne snafts int rmedia e cna oeariiigs in c_i- pump cavity for preventing adhesive materials oaing pumpeα from leadin along txie shaft from tne pump impeller into tna oeariags. Tne pump housing includes at least Oil - grease iαoricant supply caa oer. The chamoars have grease suppiy passageways interconnecting the cna oers to nign pressure inlet one-way vaive fittings on cu- exterior of CΩ,_ pump housing for supplying grease _uoricant to the cnamoers under BAD INAL pressure. The pump housing further includes interconnecting passageways from tne lubricant supply chamoers to and around tna snaft oaaring surfaces to the sealing means for iuoricαcing cne oeariags and supplying the sealing means with grease luoricant to thereoy increase and maintain tne sealing action of tne seals relative to tna pump shafts at tna ends cnaraof adjacent tne pump cavity. In tnis manner ingress or tna mg-iiy viscous and sometimes highly aorasive adhesive into tne oaaring surfaces is prevented. In preferred a oodiments of tn invention, (especially tnose intended for hign pressure application) ΛΛ miet pressure regulator vaive is connected in tne -.met port of cao adnesive uispensi.ig pump with tna inlet pressure regulator vaive oaing e__ecc .cαiiy cjacroi-. JU. Pressure saiisors are installed in taa inlet and outiat jor c or tne dispensing pump for seasiaj tna f_uid pressure across tna pump and erivin ... raedoac. d-oii't oi Sx-gnai tnat is usad to oo.ιcro_. operation or c * ιa electrically controilaole in ec regulator vaive during o_poc<_cion of the system to ...αi.-ta n α constant operating pressure across cao adhesive dispensing pu.iip. BRIEF DESCRIPTION OF J. V7I:.GS These and other oojeccs, features and many of CΛO attendant advantages of this in/an:ion wiii oe appreciated more readily as ne same oetomes oetter uiTderstood from a reading of tne following detaiiaa description, * i- considered ia conjunction with tna accompanying drawings, wnerein j.ι e parts in eacn of tna several figures are identified oy the __.. -- reference characters, and wnerein: Figure 1 is α schematic, unctional clock SAD ORIGINAL diagram of a novel adnesive dispensing pump system constructed according to tne present invention; Figure 2 is an enlarged,longitudinal, sectional view ta .en through tne adhesive gear ρ j * np snotfii ia Figure 1 suostantialiy aio.ig che staggered section line 2-2 of Figure 1; Figure 3 is a " transverse sectional view, on α smaller scale, c-. _a suostantialiy aiong che line 3-3 of Figure 2; Figure 4 is a transverse sectional view, td.idn saos aaciany axoag tne xina 4-4 of Figure 2; Figure 5 is an end view, partly in section, drcen aiong tna line 5-5 of Figure 2; Figure 6 is a perspective view of tne repiαceaoia wear piαte comprising α part of tne ear pump in sectional view in Figure 2; Figure 7 is an eniargea exploded sectional view of α snaft sealing me oer employed in the αdnesi/e gear pump comprising a ~i_.c c of the invention; Figure 3 is ά._ι enlarged end view of a snaft oaaring employed in tna αdaasiva gear pump of th invantiOii; Figure 9 is α developed view of the shaft oaaring surface of cno oaaring wnosa enu view is illustrated in Figures 3; and siio s tne internal grooves provided for tne passage _f lαoπcαting grease over and around O oaari.ι_ an into tne sealing memoer of Figure 7; Figure 13 is a functional oioc._ diagram illustrating a modified form of tne invention " tnat is o__ suited f oe applications waere it is desired co dispense adhesives under ni n pressure. or under conditions wnere it is necessary to α highly imear relationship oatwaen f _ow rate and dispensing pump speed; B ^ ORlGl NAL Figure 11 is an operating characteristic curve of t e system shown in Figure 10 wherein flow rate in gallons/ in is plotted against pump speed in rpm; and Figure 12 is a taole snowing the results of tests run with tne system of Figure 10 to αeter ma its flow rate versus pressure characteristics and snows tnat cna pressure across cna dispensing pump is essentially constant at any given pump spaed for αifrarenc pressure heads imposed on tna pump. 3ΞST -10DB OF PRACTICING THE INV3NTI0IT Figure 1 is ά schematic functional oloc. diagram of an improved adhesive dispensing pump control system for automatically changing tne flow rate of adhesive materials oaing dispensed onto α workplace in conformance witn uaαa-ges in movement ■ of an automatically controlled adnesive dispensing nozzle used co apply the aαnasivo materials onto tne surface of tne workpiece. In figure 1 the automatically controlled aozzia is sno n at 11 waicn is secured to cue end of a working arm of a rooot or otner automatically controlled mechanism snown at 12 that in turn is under cue control of a progrαm aoie control computer 13. ϊne nozzle 11 is -designed to dispense a oaaα -of adnesive, such - O- ΛΛ epoj.y, over a wor.-tpiece (not shown) in Figure 1. .\ typical wo_ .piece ignt co-uprise tne door of an αutυmooiia (for example) wnara it is desired o dispense α oaad of adhesive around cue outside perimeters of tna αoor prior to αssexaoiy. Daring ■ cna dispensing of na adnesive on cna αoor, tne speed of movement of cna nozzle must change wnen tne dispensing nozzle' reaches points in its patn -of travel wnere it must go around corners (particularly snarp corners) . Hence, at such points txie nozzle must slow down. -.hen tna nozzle BAD ORIGINAL changes its speed at the corners, the flow rate of the adhesive oeing dispensed oy the nozzle must change so as to provide a proper head pattern on the door panel. The system according to the invention is controlled so that the same control computer 13 wnich controls positioning and operation of tne adhesive dispensing nozzle 11 via iTiecnanism 12 also accomplishes the ta≤ of adjusting tne flow rate of tna adhesive material oeing dispensed to provide an even oead throughout the coating operation. For the aoove oriefly dascrioed purpose, tna adhesive pump control system according to the invention includes a novel adhesive dispensing gear pump 14 (to oe dascrioed more fully hereinafter with relation co Figures 2-9) tnat is supplied with a nigniy viscous adnesive .material which also may oe aorasive. Tne adnesive to oe dispensed is supplied froiϊi a supply tan* 15, with or without an ancillary supply pump (iot shown) through an inlet pressure regulator 15 to an inlet port of the gear ump 14. The outlet port from the gear pump 14 is supplied through an optional oacκ pressure regulator 17 to tna automatically controlled dispensing nozzle 11. In systems where the outlet pressure regulator 17 is employed to control the outlet pressure from the gear pump 14, it has oeen determined that providing a constant input and output pressure on the gear pump results in a suostantialiy constant operating pressure across tne dispensing gear pump at different flow rates and provides superior flow control of the adhesive oeing dispensed due to the fact that the gear pump is made uca less sensitive to cnanges in material viscosity. Recorded data suggests that pumping fiow rate error due to changes in viscosity can oe BAD ORIGINAL reduced from 16% to 5% using the inlet and outlet pressure regulators. For systems where extreme changes in viscosity, due to changes in temperature, etc., do not occur, then the inclusion of the outlet pressure regulator 17 is not required. In such systems, the outlet port from the gear pump 14 would oe connected directiy through suitaole conduits to the automatically controlled dispensing nozzle 11. The dispensing gear pump 14 is driven through suitaole reduction gears shown at 13 that are driven from a servo motor 19 under the control of a servo drive electronic controller 21. The servo drive electronic controller 21 in turn is controlled oy the control computer 13 in conjunction with the positioning mechanism 12. Consequently, changes in movement of the automatically controlled rooot functions positioning mechaniSjm 12 required to position the dispensing nozzle 11 at a particular point in its patn of travel are synchronized with changes in speed of tne servo motor 19 and nance the gear puiTip 14 wnereoy the flow rate of an adhesive material oeing dispensed is changed automatically wicn changes in the path of movement of the adnesive dispensing nozzle 11. In the aoove oriefly descrioed system, control signals from tne control computer 13 are fed co the automatically controlled positioning mechanism 12 (which includes on-off control of nozzle 11) to move the adhesive dispensing nozzle 11 to a predetermined point in its path of travel over a workpiece. Concurrently, corresponding commands from the control computer 13 are fed to the servo drive electronic controller 21 and the electronic controller output provides necessary β *0 O Q i At control power to the servo drive motor 19. The servo motor speed thus is caused to conform to the pattern of movement of the adhesive dispensing nozzle 11. Output from servo motor 19 is transmitted to the gear pump 14 oy speed reducing gears 13 so as to provide necessary torque to the gear pump 14. In this manner, the output from tne gear pump provides a flow of adhesive material wnose flow rate is under the direct control of the control computer 13 and synchronized with the pattern of movement of the dispensing nozzle 11. Figure 2 is a longitudinal sectional view of the adhesive gear pump 14 taken along staggered line 2-2 of Figure 1. The gear pump 14 has been designed to pump adhesives, which in many cases are extremely viscous and aorasive at a variably controlled flow rate determined y control computer 13. 3ecause of the characteristics of the adhesive j_aterial oeing pumped, it is necessary that gear pump 14 be specially designed to prevent ingress of the adhesive into the oearings of tne pump. For tnis purpose, the pump 14 is provided with a unique seal and luorication system designed into the pump housing and related to the gears, the shafts, the seals, replaceaole wear plates and tne oearings as will oe descrioed hereinafter. As oest snown in Figure 3, adhesive to oe dispensed enters the pump inlet port 22 at a regulated input pressure from inlet regulator IS wnere it comes into contact with tne interrαeshing gear pump rotors or impellers 23 and 24. Impellers 23 and 24 are rotataoly supported in a pump cavity 35 within housing 14, -and force the adhesive out through an outlet port 25 opposite the inlet port 22 (snown in dotted outline form in Figure 2) under increased pressure which may or may not oe regulated dependent upon whether the inlet and outlet pressure regulator valves 16 and 17 are employed. The flow rate of the adhesive which is highly viscous and may oe somewhat abrasive is determined by the speed of rotation of the inter eshing gear p j-np impellers 23 and 24 which in turn is dependent upon the speed of the servo motor 19 as explained above. As best shown in Figure 2, the gear pump impellers 23 and 24 are keyed to and rotate with respective parallel drive snafts 26 and 27. The drive shaft 26 is coupled to and rotatably driven oy a drive shaft 28 from the reducing gears 18. Drive shaft 23 is in axial alignment with the rotor drive snaft 26 and is secured thereto oy a suitable coupling such as a threaded stud on the end of rotor drive shaft 26 received in a complementary threaded socket opening in the end of reduction gearing drive shaft 23. The drive shaft 27 constitutes an idler shaft within the gear pump housing 14 and is driven oy main drive shaft 26 via intermeshing gear impellers 23, 24. The gear pump impeller drive snafts 26 and 27 are rotatably supported in parallel alignment within gear housing 14 by suitable journal oearings snown at 31, 32, 33 and 34. To prevent egress of che adhesive material being pumped out of the pump cavity 35 within which the gear pump impellers 23 are supported, as best seen in Figure 3, and thereafter leach or otherwise oe forced out along the drive shafts 26 and 27 into the space between the respective drive shafts and their supporting journal oearings 31, 32 and 33, 34, four Parker Poly-Pak seals are provided as shown at 36, 37 and 33, 39. The construction of Poly-Pak seals 36, 37 and 38, 39 is shown in greater detail in Figure 7. The seals 36 and 37 are positioned around the rotor impeller drive shaft 26 at each end thereof outside the walls of the cavity 35 through which the adhesive is oeing pumped passes, and are disposed intermediate the oearings 31 and 32 and the respective ends of the pump impeller-rotor 24. Similarly, the pump impeller drive shaft 27 has the seals 33 and 39 disposed therearound at positions intermediate the oearings 33 and 34 and the respective ends of tne ρu_nρ impeller-rotor 23. Figure 7 is an enlarged cross sectional view of tne construction of one of the Poly-Pak seals 36, 37, 38 and 39. Since the seals are identical in construction, only seal 37 has been illustrated. The Poly-Pak seals are comprised by an annular, tapered oody emoer 41 of pliable resilient plastic material which is press fitted over tne end of the shaft 26 at a position " intermediate tne journal oearing 32 and the wall portion of the housing 14 which defines the pump cavity 35 in which the gear pump impellers 23 and 24 are rotataoly supported. The tapered annular resilient plastic memoer 41 has an annular-shaped groove snown at 42 formed around the end thereof and a resilient O-ring seal 43 is press-fit into this groove in order to enhance the gripping aoility of the seal memoer 41 to the interior surrounding surface of housing 14 to enhance sealing of tne surface of tne shaft 26 wnich it " surrounds. The remaining Poly-Pak seals 37, 38 and 39 are similarly constructed and all four Poly-Pak seals are arranged with tne enlarged diameter end thereof containing the O-ring seal 43 pressed against the end surface of the cavity housing tnrougn whicn snaft 26, or alternatively shaft 27, passes. -U- As best shown in Figure 4 of the drawings, each of the end faces of the pump cavity housing through which the shafts 26 and 27 pass have circular depressions formed therein in which annular, soft orass wear plates 45 and 46 are secured at each end of each shaft. The wear plates 45, 46 together with a similar pair of wear plates at tne opposite end of the pump cavity form wear surfaces coacting with tne respective ends of the gear pump impellers 23 and 24 for containing the adhesive within the pump cavity 35. Figure 6 is a perspective view of one of the replaceaole wear plates, such as 45. The pump housing 14 has a plurality of grease luoricant supply cha oers formed therein oest seen in Figure 2 at 51, 52, 53 and 54. These chamoers are connected by interconnecting passageways to respective hign pressure inlet, one¬ way valve grease fittings shown at 55, 56, 57 and 58, respectively, for supplying luoricant grease under high pressure to each of the respective supply chamoers. The inlet one-way valve fittings 55, 56, 57 and 58 are standard grease fittings and are mounted on the exterior of the housing 14 so as to Oe readily accessiole to a serviceman for replenishing the luoricant grease supply in the respective supply chambers. Luoricant grease from each of the respective supply chamoers is supplied to oearings 31, 32, 33, 34 through grease luoricating passageways shown at 59 in Figure 2 formed in the surface of tne respective journal oearings 31, 32, 33 and 34. Figure 8 is an enlarged end view of one of the shaft bearings 31, for example, which illustrates clearly a groove 59 formed in the surface of the oearing for tne supply of lubricant grease to the shaft and bearing in which it is formed. Figure 9 is a developed view of the journal bearing 31 shown in Figure 8 and best illustrates how lubricant grease supplied through the passageways 59 of the respective bearings serves to maintain the shaft and bearing surfaces well lubricated with grease so as to minimize friction and wear and prevent ingress of adhesive into the space oetween the shaft and the bearing. The grooved passageways 59 in all of the oearings 31, 32, 33 and 34 terminate at a small gap shown at 51 oetweeh the ends of the respective oearings 31, 32, 33 and 34 and the aoutting ends of their respective Poly-Pak seal units 36, 37, 38 and 39. Interconnecting high pressure luoricant passageways shown at 52, 53, 54 and 65 serve to interconnect all of the gaps 61 of botn shafts 26 and 27 together in a common lubricant supply system with the passageways 64 and 55 oeing interconnected with respective high pressure outlet relief valves ββ and 57 tnreaded into the outer surface of the pump casing 14. Witn this arrangement, luoricant grease is supplied oy a suitaole grease gun through the respective grease inlet one-way valves 55, 56, 57 and 58 where it is ouilt up in the supply chamoers 51, 52, 53 and 54. From the supply chambers, the grease is forced througn the lubricating passageways 59 in the respective journal oearing shell to the gaps 61 and to and through the interconnecting passageways 62, 63, 64 and 55. As oest seen in Figure 7, the gaps 61 also communicate with small gaps shown at 58 which exist oetween the outer tapered surface of the resilient sealing memoers 41 of all the Poly-Pak seals 36, 37, 38 and 39 sucn as the seal 37, for example. As a result of this interconnection, luoricant grease is forced through the bearing passageways 59, through the gaps 61 and into and around the bulk of the exterior tapered surfaces of the Poly-Pak seal emoers 41. Consequently, any adhesive which might tend to leak out of the pump cavity through the central openings in the replaceable wear plates and tne end wall of the portion of the pump housing supporting the wear plates and defining the pump cavity, is prevented from further travel along the shaft and into the bearings by the incompressible luoricant grease filling the gaps and coacting with the Poly-Pak seal memoers 35, 37, 38 and 39 to prevent ingress of the adhesive into and around the oearings and shafts 26 and 27. To hold the impellers 23 and 24 in place on snafts 26 and 27, snap rings 69 are provided within the pump cavity* at each end of the pump impeller shafts as best shown in Figure 2. The snap rings 59 are of conventional construction. Also to assure proper sealing of the pump unit at its point of connection to the reduction gearing 18, an additional Poly-Pak seal unit 71 is provided in a cup-shaped reimovable plate 72 best seen in Figure 2 and Figure 5 of the drawings. Plate 72 provides an access opening to the internally threaded end of snaft 26 whereby the shaft 28 of the reduction gear 18 readily may be secured to the drive shaft 26 of the pump unit. When placing tne novel adhesive gear pump provided oy the invention in operation, the luoricant grease system is filled with lubricant grease to a pressure of the order of 1000 pounds per square inch gauge. Because of the improved sealing action provided oy the Poly-Pak seal units 35, 37, 38 and 39, the high pressure grease is confined to the luorication system and its interconnecting passageways and prevented from entering into the pump cavity. Thereafter, when the pump is operated and adhesive is being pumped under pressure, the luoricant grease already has filled any possiole leakage paths existing in spaces on the luoricant side of the pump cavity 35 and adhesive is .prevented from leaking out of the pump cavity. After several months of operation, it is desiraole to shut down the pump for periodic servicing, loosen the screws in che outlet relief valves 55 and 57 in tne pump housing, and thereafter pump out the old luoricant grease and replace it with new fresh lubricant grease on a systematic maintenance schedule to assure long-term reliaole operation of the pump in service. From tne aoove description it is clear that the adnesive pumping system is designed primarily for tne dispensing of single part adhesives at amoient temperature. However, not melt liquid adhesives can oe dispensed at elevated temperatures, wnich upon cooling provide solid structural oonding. While using not .tielts, the improved pumping system controls the dispensed flow rate of tne hot melt adhesive synchronously with tne movement of tne adhesive dispensing nozzle in tne manner descrioed earlier. This can oe accomplished oy heating the pump unit in a high temperature cnamoer. Such arrangement also can oe used to staoilize tne temperature of any adhesive oeing dispensed to tnereoy stabilize the viscosity of tne adnesive at a desired value. Additionally, tne adhesive pumping system provided oy the invention is not limited to use witn single-part adnesives, out also can oe employed witn a class of adhesives called two-part adhesives which are commonly known. Two-part adhesives. However, require precise mixing prior to application on the workpiece where they cure due to a chemical reaction. The mixing must be achieved subsequent to the pump unit. Hence, two separate systems employing a separate nozzle for each part of the two-part adhesive can be used. In such arrangement the second nozzle dispenses its part over the bead traced out by the first part. The two-part mixture otherwise is dispensed in the manner described above with respect to single part adhesives. Figure 10 of the drawings illustrates an embodiment of the invention intended for use in applications requiring the adhesive to be dispensed at high pressure of the order of 2000 pounds per square inch gauge or where it is necessary that there be a linear relation between flow rate of adhesive and dispensing pump speed at a given pressure. The system is comprised by an automatically controlled dispensing nozzle 11 which is secured to the end of a working arm of a robot or other similar automatically controlled movement mechanism shown at 12 that in turn is under the control of a programmable control computer 13. The nozzle 11 is designed to dispense a bead of adhesive, such as an epoxy, over a workpiece 10 which might comprise the door of an automobile (for example) where it is desired to dispense a bead of adhesive around the outside perimeters of the door prior to assembly. The system is designed so that it is controlled by the same control computer 13 which controls (via robot jmechanism 12) positioning of the adhesive dispensing nozzle 11 as well as on- off control of the nozzle on-off control valve 11V normally comprising a part of the nozzle 11, and also accomplishes the task of adjusting the flow rate of the adhesive material being dispensed by nozzle 11 to provide an even bead throughout the adhesive coating operation. In the Figure 10 embodiment of the invention, inlet regulator valve 16 is a variably controlled regulator valve whose output pressure can oe variaDly controlled over a predesigned range of values. Such variaoly controlled regulator valves for use with high viscosity fluids such as adhesives and other mastics are available on the market commercially. One suitable regulator valve for this purpose is the Deltrol Valve - Model ENL- 355 manufactured and sold oy the Deltrol Company of Dellwood, Illinois. The flow and output pressure characteristics of variably controlled regulator valve 16 is directly controlled oy a valve drive motor 81 which is either integrally mounted with valve 16 or remotely mounted, and mechanically connected with tne movable flow controlling element of variaole controlled regulator valve 16. Valve drive motor 81 in turn is controlled oy the output electrical signal fed back from a valve drive motor control circuit 82 comprising part of a feedback servo control loop to be described hereafter. For systems employing a variably controlled inlet pressure regulator valve 16, it is desirable also to provide in the system a mastic or adhesive supply pump 15 interposed in the system between a supply tank for the mastic (not shown) and the variably controlled inlet regulator valve 16, . A numoer of known commercially available supply pumps are availaole for this function to supply adhesives and other mastics up to 2000 psi gauge or greater, out are known to possess discharge output characteristics which are somewhat erratic due to the production of pulsed (sudden) changes in their output pressures while operating. To limit the undesirable effects of such pulsed discharge pressures to the inlet of the variably controlled pressure regulator valve 16, it is desirable (if not necessary) to include in the discharge line from supply pump 15P to inlet regulator valve 16 a further preset pressure regulating valve 15V, if one is not already provided for the supply pump by its manufacturer. Pressure sensor 83 and 84 are connected respectively in the inlet and outlet ports of adhesive dispensing gear pump 14 for deriving output electrical signals representative of the value of the pressure of the adhesive at the inlet and outlet of gear pump 14. The pressure related output signal from outlet pressure sensor 84 is supplied through an input resistor to the- input of a feedback stabilized operational amplifier 85 of conventional construction. The output signal from inlet pressure sensor 83 is supplied directly to a first summing resistor in the input of a summing operational amplifier 86. The output from outlet operational amplifier 85 is supplied to a second summing resistor connected in parallel with the first resistor to the input of summing amplifier 86 together with a constant reference value signal supplied through a third summing resistor connected in parallel with the first and second summing resistors to the input of summing amplifier 86. Amplifier 86 sums together all three inputs and derives at its output terminal an error signal representative of any difference. This error signal is supplied through a uirity-gain operational amplifier 37 connected in a known manner to operate as an invertor for supplying the error signal with proper polarity to control the operation of valve drive motor 81 via control circuit 82. In operation, the feedback servo-control loop comprised by elements 83 through 87 functions as a pressure-position servo control feedback loop to control the opening of regulatable inlet valve 16 so as to dynamically force the inlet pressure to gear pump 14 to lag the pump outlet pressure by a predetermined amount set by the reference applied to the third summing resistor of summing amplifier 86. In a particular design of the system this value was set to be 100 psi gauge. Thus the feedback servo control loop functions (in the specific example cited) to maintain the relation: P = P. + 100 psi (1) o 1 Any deviation from the above described operating condition results in the production of an error signal of appropriate magnitude and polarlity to return the system to the stated condition set forth in expression (1) above. In this manner the pressure across (being developed) the gear pump 14 is held constant regardless of flow rate or delivery pressure of the adhesive being dispensed. The embodiment of the invention shown in Figure 10 and described aoove provides the following additional advantageous features: 1. Positive displacement; flow is near linear function of input voltage to the servo drive electronic, controller 21 as shown in Figure 11 of the drawings. 2. Flow is independent of delivery pressure. Unlike conventional dispensing pump systems the efficiency curve developed by the system of Figure 10 is essentially a straight line as shown by the Taole in Figure 12. 3. Torque required to drive the pump is very low and approximately constant regardless of delivery pressure up to very high values. The energy under such conditions is supplied by the adhesive material delivered by the larger industrial grade supply pump 15P normally located on the ground via controllable regulator valve 16. 4. Adhesive material delivery of 0.8 GP at 0 to 2000 psi is possible with the system shown in Figure 10. 5. Because of the low duty imposed on the gear pump in the system of Figure 10 (increase in pressure of only 100 psi in the example cited) long operating life expectancy for the system is assured. INDUSTRIAL APPLICABILITY The present invention provides a computer programmable, positive displacement pumping system which employs a novel adhesive dispensing gear pump of relatively lightweight, compact and efficient construction for dispensing adhesives and other mastics at selectively controlled flow rates and pressures over a wide range of values. In a typical installation, the pumping system automatically dispenses adhesive on a part, such as an automotive door, with a rooot or otner automatically positioned and controlled nozzle. During the dispensing of the adhesive onto the door,, the speed of the automatically controlled nozzle must change at different points in its travel, for example, around sharp corners where the nozzle must slow down. As the nozzle changes its speed, the flow rate of the adhesive also is changed so as to provide a proper adhesive bead pattern on the part being processed. The same control computer controls both the motion of the automatically controlled adhesive dispensing nozzle and the flow rate of the pump supplying the adhesive to be dispensed. The invention employs a new and improved adhesive gear pump for displacing the adhesive material to be dispensed. The gear pump used with the invention has been specifically designed for very high viscosity adhesives, such as epoxies, which are sensitive to temperature and sometimes can be very abrasive. With such adhesives, the improved pump system does not cause curing of the adhesive during operation. 1. Programmable positive displacement flow control of the adhesive oeing dispensed. 2. Flow rate relatively insensitive to changes in viscosity due to changes in temperature. 3. Adhesive has negligible temperature rise from the adhesive pump output to the nozzle (aoout 2 degrees Fahrenheit) . 4. Pump is abrasive resistant so as to provide long operating life under expected factory operating conditions. 5. The pump system provides faster adhesive dispensing times due to the ability to increase flow rates on straight- line oeads while automatically providing slower flow rates at corners or other turns where the dispensing nozzle must slow down. Because of its unique design, the dispensing pump system made availaole by the invention operates to maintain suostantialiy constant pressure across the dispensing pump used in the system thereby making the overall dispensing system relatively insensitive to changes in viscosity of- the adhesive oeing dispensed, and allowing the system to be employed in high pressure adhesive dispensing operations and in situations requiring a highly linear relation between dispensing pump speed and flow rate of the adhesive being dispensed. Having described two embodiments of a novel high pressure variable flow rate adhesive dispensing pump control system constructed in accordance with the invention, it is believed obvious that other modifications and variations of the invention will be suggested to those skilled in the art in the light of the aoove teachings. It is therefore to be understood that changes m'ay be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.

Claims: WHAT IS CLAIMED IS: 1. An adhesive dispensing pump system for automatically changing the flow rate of adhesive being dispensed to a workpiece in conformance with changes in movement of an automatically controlled adhesive dispensing nozzle used to apply a predetermined pattern of adhesive around the surface of the workpiece; said improved adhesive dispensing pump system comprising an adhesive dispensing pump for supply of adhesive material under pressure to a dispensing nozzle mounted on and moved by an automatically controlled dispensing machine over a preprogrammed path of movement for dispensing adhesive in a preprogrammed pattern onto a workpiece, said adhesive dispensing pump being driven by a variable speed electric servo drive motor, and a servo drive electronic motor controller coupled to and controlling the speed of the servo drive motor, said automatically controlled dispensing machine having a programmable control computer for controlling movement of the adhesive dispensing nozzle in tracing out the predesigned pattern of adhesive being dispensed, and said servo drive electronic motor controller also oeing controlled by the control computer of the automatically controlled dispensing machine in conjunction with the movement of the adhesive dispensing nozzle whereby the speed of the adhesive dispensing pump is synchronized with the movement of the adhesive dispensing nozzle. 2. An adhesive pump system according to claim 1 further including means for maintaining a substantially constant pressure across the adhesive dispensing pump during operation. 3. An adhesive pump system according to claim 2 wherein the means for maintaining a substantially constant pressure across the adhesive dispensing pump comprise inlet and outlet fluid pressure regulator valves connected respectively in the inlet port and the outlet port of the adhesive dispensing pump. 4. An adhesive pump system according to claim 2 wherein the means for maintaining a substantially constant pressure across the adhesive dispensing pump comprises a dynamically controllable fluid pressure regulating valve connected to the inlet port of the adhesive dispensing pump, said controllable pressure regulating valve oeing dynamically adjusted to maintain a desired pressure across the dispensing pump during operation. 5. An adhesive pump system according to claim 4 wherein said system includes a separate supply pump for supplying adhesive under pressure to the inlet of the adhesive dispensing pump and further includes adhesive pressure sensing means connected to ooth the inlet and outlets of the adhesive dispensing pump for sensing the pressure across the adhesive dispensing pump and deriving a feedback signal therefrom that is supplied back to the controllable fluid pressure inlet regulating valve for dynamically adjusting the inlet valve during operation of the system to maintain a constant operating pressure across the adhesive dispensing pujmp. 6. An adhesive pump system for automatically changing the flow rate of adhesive oeing dispensed onto a workpiece in conformance with changes in movement of an automatically controlled adhesive dispensing nozzle used to apply a predetermined pattern of adhesive around the surface of the workpiece; said improved adhesive pump system comprising an adhesive dispensing pump having a pump housing defining a pump cavity having at least one inlet port and one outlet port, rotatable pump impeller means supported within the pump cavity for physically pumping adhesive supplied thereto through the inlet port to the outlet port at a flow rate dependent upon the rotational speed of the pump impeller means, said pump impeller means being secured to and rotatable witn at least one rotataole pump shaft, shaft oearing means secured within said pump housing for rotataoly supporting the pump impeller shaft, sealing means disposed around the shaft intermediate the bearing means and the pump cavity for preventing leakage of the adhesive materials being pumped along the shaft from the pump cavity into the bearings, said pump housing including at least one grease lubricant supply chamber having grease supply passageways interconnecting the chamber to high pressure inlet one-way valve fittings on the exterior of the pump housing for supply grease lubricant thereto under pressure, and said pump housing further including interconnecting passageways from the lubricant supply chamber to and around the shaft bearing surfaces to the sealing means for pressurizing the sealing means with grease lubricant for increasing and maintaining the sealing action of the seal relative to the pump shaft at the end thereof adjacent the pump cavity; said adhesive dispensing pump supply adhesive material to a dispensing nozzle mounted on and moved by an automatically controlled dispensing machine over preprogrammed, aths of movement for dispensing an adhesive in a predetermined pattern onto the workpiece, said adhesive dispensing pump being driven by a variable speed electric servo drive motor; a servo drive electronic motor controller coupled to and controlling the speed of the servo drive motor; and a programmable control computer for automatically controlling movement of the adhesive dispensing nozzle in tracing out the adhesive being dispensed in a predetermined pattern, said servo drive electronic motor controller also being controlled by the control computer in conjunction with the movement of the adhesive dispensing nozzle whereby the speed of the adhesive dispensing pump is synchronized with the movement of the adhesive dispensing nozzle. 7. An adhesive pump system according to claim 6 further including means for maintaining a substantially constant pressure across the adhesive dispensing pump during operation. 8. An adhesive pump system according to claim 7 wherein a programmably controllable inlet fluid pressure regulating valve is connected to the inlet port of the adhesive dispensing pump which can be dynamically adjusted to maintain a desired pressure across the dispensing pump during operation. 9. An adhesive pump system according to claim 8 wherein said system includes a separate supply pump for supplying adhesive under pressure to the inlet of the adhesive dispensing pump and further includes adhesive pressure sensing means connected to ooth the inlet and outlets of the adhesive dispensing pump for sensing the pressure across the adhesive dispensing pump and deriving a feedback signal therefrom that is supplied back to the controllable fluid pressure inlet regulating valve for dynamically adjusting the inlet valve during operation of the system to maintain a constant operating pressure across the adhesive dispensing pump. 10. An adhesive pump system according to claim 6 further including additional grease lubricant outlet passageways interconnecting the sealing means to relievable outlet valve means on the exterior of the pump housing whereby the lubricant grease periodically can be flushed out of the housing lubricant chamber and passageways and replaced with fresh lubricant grease under pressure. 11. An adhesive pump system according to claim 10 wherein the interconnecting passageways from the lubricant grease supply chamber to and around the shaft bearing ' inside surfaces includes grooved passageways formed in the inside surfaces of the bearing that support the pump impeller drive shaft whereoy lubricant grease continuously is supplied to that portion of the pump impeller drive shaft supported within the bearings to insure a well lubricated surface lubricant under pressure and prevents ingress of the adhesive being pumped into the space between the rotating impeller shaft and the oearing surface. 12. An adhesive pump system according to claim 11 wherein the sealing means includes an annular, pliable resilient sealing member having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing member facing the back wall of the adhesive containing cavity and wherein lubricant grease is driven into the O-ring closed open face of the U- shaped cross section sealing member to cause it to firmly grip and seal the shaft in the space between the rotating pump impeller and the sealing member. 13. An adhesive pump according to claim 12 wherein the sealing means is disposed oetween the bearing means and the back side of the housing wall that supports the wear plates in the pump cavity, the sealing means includes annular, pliable resilient sealing members having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing members and contained 0-rings being disposed opposite and facing the oack side of the pump housing wall supporting the wear plates whose opposite surface forms one surface of the pump cavity and wherein lubricant grease is driven into the O-ring closed open face of the U-shaped cross section sealing memoer under pressure to cause it to firmly grip the shaft and seal the space between the rotating pump impeller shaft and the sealing member. 14. An adhesive pump system according to claim 13 wherein the rotatable pump impeller means comprises a set of intermeshing gear wheels that form a gear pump. 15. An adhesive pump system according to claim 14 further including inlet and outlet fluid pressure regulator valves connected respectively in the inlet port and the outlet port of the adhesive dispensing pump. 16. An adhesive pump system according to claim 14 wherein a programmably controllable fluid pressure regulating valve is connected to the inlet port of the adhesive dispensing pump which can oe dynamically adjusted to maintain a desired pressure across the dispensing pump during operation. 17. An adhesive pump system according to claim 16 wherein said system includes a separate supply pump for supplying adhesive under pressure to the inlet of the adhesive dispensing pump and further includes adhesive pressure sensing means connected to both the inlet and outlets of the adhesive dispensing pump for sensing the pressure across the adhesive dispensing pump and deriving a feedback signal therefrom that is supplied back to the controllable fluid pressure inlet regulating valve for dynamically adjusting the inlet valve during operation of the system to maintain a constant operating pressure across the adhesive dispensing pump. 18. An improved adhesive pump control system for automatically changing the flow rate of adhesive materials being dispensed onto a workpiece in conformance with changes in movement of an automatically controlled adhesive dispensing nozzle used to apply the adhesive materials onto the surface of the workpiece; said improved adhesive pump control system comprising a variable speed adhesive dispensing pump for supplying adhesive materials to a dispensing nozzle mounted on and moved by an automatically controlled dispensing machine over a preprogrammed patn of movement for dispensing the adhesive materials in a predetermined pattern onto the workpiece, said adhesive dispensing pump being driven by a variaole speed electric servo drive motor, a servo drive electronic motor controller coupled to and controlling the speed of the servo drive motor, said automatically controlled dispensing machine having a programmable control computer for controlling movement and operation of the adhesive dispensing nozzle while dispensing the adhesive material in a predetermined pattern onto the workpiece, and said servo drive electronic motor controller oeing controlled by the control computer of the automatically controlled dispensing machine in conjunction with the movement of the adhesive dispensing nozzle whereby the speed of the adhesive dispensing pump and hence the flow rate of the adhesive being dispensed is synchronized with the movement of the adhesive dispensing nozzle. 19. An adhesive pump system according to claim 18 further including means connected across the inlet port and the outlet port of the adhesive dispensing pump for maintaining a substantially constant operating pressure across the dispensing pump during operation. 20. An adhesive pump system according to claim 19 wherein a programmably controllable inlet fluid pressure regulating valve is connected to the inlet port of the adhesive dispensing pump which can be dynamically adjusted to maintain a desired constant pressure across the dispensing pump during operation. 21. An adhesive pump system according to claim 20 wherein said system includes a separate supply pump for supplying adhesive under pressure to the inlet of the adhesive dispensing pump and further includes adhesive pressure sensing means connected to both the inlet and outlets of the adhesive dispensing pump for sensing the pressure across the adhesive dispensing pump and deriving a feedback signal therefrom that is supplied back to the controllable fluid pressure inlet regulating valve for dynamically adjusting the inlet valve during operation of the system to maintain a constant operating pressure across the adhesive dispensing pump. 22. An adhesive pump comprising a pump housing defining a pump cavity having at least one inlet port and one outlet port, rotatable pump impeller means supported within the pump cavity for physically pumping adhesive supplied thereto through the inlet port to the outlet port at a flow rate dependent upon the rotational speed of the pump impeller means, said pump impeller means being secured to an rotatable with at least one rotatable pump shaft, shaft bearing means secured within said pump housing for rotatably supporting the pump impeller shaft, sealing means disposed around the shaft intermediate the bearing means and the pump cavity for preventing leakage of the adhesive materials oeing pumped along the shaft from the pump cavity into the bearings, said pump housing including at least one grease luoricant supply chamoer having grease supply passageways interconnecting the chamber to high pressure inlet one-way valve fittings on the exterior of the pump housing for supplying grease luoricant thereto under pressure, and said p j-np nousing further • including interconnecting passageways from the luoricant supply chamber to and around the shaft oearing surfaces to the sealing means for pressurizing the sealing means witn grease lubricant for increasing and maintaining the sealing action of the seal relative to the pump shaft at the end thereof adjacent the pump cavity. 23. An adhesive pump according to claim 22 further including additional grease luoricant outlet passageways interconnecting the sealing means to relievable outlet valve means on the exterior of the pump housing whereby tne lubricant grease periodically can oe flushed out of the housing lubricant chamber and passageways and" replaced with fresh luoricant grease under pressure. 24. An adhesive pump according to claim 22 wherein the interconnecting passageways from the luoricant grease supply chamber to and around the shaft bearing inside surfaces includes grooved passageways formed in the inside surfaces of the bearing that support the pump impeller drive shaft whereby lubricant grease continuously is supplied to that portion of the pump impeller drive shaft supported within the bearings to insure a well lubricated surface lubricant under pressure and prevents ingress of the adhesive being pumped into the space between the rotating impeller shaft and the bearing surface. 25. An adhesive pump according to claim 23 wherein the interconnecting passageways from the lubricant grease supply chamber to and around the shaft bearing surfaces includes grooved passageways formed in the inside surfaces of the bearing that support the pump impeller drive shaft whereby lubricant grease continuously is supplied to that portion of the pump impeller drive shaft supported within the bearings to insure a well lubricated surface lubricant under pressure and prevents ingress of the adhesive being pumped into the space between the rotating impeller shaft and the bearing surface. 26. An adhesive pump according to claim 22 wherein the sealing means includes an annular, pliable resilient sealing member having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing member facing the back wall of the adhesive containing cavity and wherein lubricant grease is driven into the O-ring closed open face of the U-shaped cross section sealing member to cause it to firmly grip and seal the shaft in the space between the rotating pump impeller and the sealing member. 27. An adhesive pump according to claim 25 wherein the sealing means is disposed between the bearing means and the back side of the housing wall that supports the wear plates in the pump cavity, the sealing means includes annular, pliable resilient sealing members having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing members and contained O-rings being disposed opposite and facing the back side of the pump housing wall supporting the wear plates whose opposite surface forms one surface of the pump cavity and wherein lubricant grease is driven into the O-ring closed open face of the U-shaped cross section sealing memoer under pressure to cause it to firmly grip the shaft and seal the space between the rotating pump impeller shaft and the sealing member. 28. An adhesive pump according to claim 22 wherein the rotatable pump impeller means comprises a set of intermeshing gear wheels that form a gear pump. 29. An adhesive pump according to claim 27 wherein the rotatable pump impeller means comprises a set of intermeshing gear wheels that form a gear pump. 30. An adhesive gear pump comprising a pump housing defining a pump cavity having an inlet port and outlet port, a pair of intermeshing gear pump rotors supported within the pump cavity for physically pumping adhesive materials flowing through the inlet port to the outlet port at a flow rate dependent upon the rotational speed of the gear pump rotors, said gear pump rotors being secured to and rotataole with respective gear pump rotor drive shafts, drive shaft bearing means secured within said pump housing for rotatably supporting the respective gear pump rotor drive snafts, sealing means disposed around each of the drive shafts intermediate the respective bearing means and the pump cavity for preventing leakage of the adhesive materials being pumped from leaking along the shafts from the respective gear pump rotors into their respective drive shaft supporting bearings whereby adhesion to and erosion of the bearings by the adhesive materials is prevented, said pump housing including at least lubricant grease supply chamber having grease supply passageways interconnecting the chamber to high pressure inlet one-way valve fittings on the exterior of the pump housing for supply grease lubricant thereto under pressure, and said pump housing further including interconnecting passageways from the lubricant supply chamber to and around the shaft bearing surfaces to the sealing means for pressurizing the sealing means with lubricant grease for increasing and maintaining the sealing action of the seal relative to the pump shaft at the end thereof adjacent the pump cavity. 31. An adhesive pump according to claim 30 further including additional grease luoricant outlet passageways interconnecting the sealing means to relievaole outlet valve means on the exterior of the pump housing whereoy the luoricant grease periodically can be flushed out of the housing lubricant chambers and passageways and replaced with fresh lubricant under pressure. 32. An adhesive pump according to claim 31 wherein the interconnecting passageways from the luoricant grease supply chamber to and around the shaft bearing surfaces include grooved passageways formed in the surfaces of the bearing that support the pump impeller drive shaft whereoy lubricant grease under pressure continuously is supplied to that portion of the pump impeller drive shaft supported within the bearings to insure a well lubricated surface and prevents ingress of the adhesive being pumped from leaking into the space between the rotating impeller shaft and the bearing surface. 33. An adhesive pump according to claim 32 wherein the sealing means includes an annular, pliable, resilient sealing member having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing member and O-ring being disposed opposite and facing the back side of the wall portion of the pump housing whose opposite surface forms one surface of the pump cavity and wherein high pressure lubricant grease is driven into the O-ring closed open face of the U-shaped cross section sealing member to cause it to firmly grip and seal the shaft in the space between the rotating pump impeller and the sealing member. 34. An adhesive pump according to claim 33 wherein the sealing means is disposed oetween the bearing means and the side of the pump housing supporting the wear plate in the pump cavity, the sealing means includes an annular, pliable, resilient sealing member having a U-shaped cross section closed by an O-ring with the open face of the U-shaped cross section sealing member being disposed opposite and facing the back side of the wall portion of the housing supporting the wear plate and defining the pump * cavity and wherein high pressure lubricant grease is driven into the O-ring closed open face of the U-shaped cross section sealing member to cause it to firmly grip and seal the shaft in the space between the rotating pump impeller and the sealing member.

Inventors: CROTTY C ALAN, GEISEL DONALD J, PILARSKI RICHARD J, CROTTY, C., ALAN, GEISEL, DONALD, J., PILARSKI, RICHARD, J.
Applicants: ROBOTICS INC, ROBOTICS, INC.
Application year: 1987
Main classification: B05C11
IPC codes: B05C11, F04C2, F04C14, F16J15, G05D7