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(11) | EP 0 095 181 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Liquid applicator apparatus Flüssigkeitsauftragsvorrichtung Appareil pour appliquer un liquide |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] This invention relates to liquid applicator apparatus of the type which includes a nozzle having a tip through which a liquid is dispensable; a sump'adapted to contain a material which prevents hardening of said liquid; a cam member; drive means for moving said cam member; means for operatively coupling said nozzle and said sump to said cam member, which when driven provides for movement of said nozzle and sump between a common storage position in which said nozzle tip is located in said sump and an operating position for said nozzle for applying liquid and a standby position of said sump outside the path of movement of said nozzle, respectively; spring means associated with said nozzle and said sump, respectively, for moving them towards a common storage position.
[0002] US-A-3,908,869 (Little) discloses apparatus for dispensing an air-curable liquid, such as a silicone rubber, through a nozzle. During periods of non-use, clogging of the nozzle is avoided by a mechanism which automatically moves the dispensing end of the nozzle to a storage position in which it is immersed in a reservoir of liquid, such as oil. The oil forms an air-tight seal around the end of the nozzle. After the nozzle is immersed in the oil, all air-contacted material in the nozzle is purged from the nozzle into the oil and then a back pressure is applied to the material in the nozzle to draw part of it upwardly into the nozzle and thus draw some of the oil from the. reservoir into the nozzle. The apparatus of the Little patent (US-A-3,908,869) is described as useful for forming a silicone rubber gasket. While the apparatus disclosed in the above-mentioned patent prevents nozzle clogging during periods of non-use, the nozzle must undergo a relatively complex motion each time it is removed from and returned to its storage position. The reason for this is that the storage reservoir is stationary and the nozzle must move in two mutually perpendicular directions relative to it in order to move between its storage and operating positions. This movement slows down the liquid dispensing process and limits the use of such apparatus. Moreover, should there be an interruption in the power applied to the nozzle moving mechanism, the nozzle will not return automatically to its storage position, and clogging will be inevitable.
[0003] US-A-3,709,110 discloses liquid applicator apparatus of the above-defined kind. While the apparatus disclosed prevents nozzle clogging during periods of non-use, the design is rather complex. Three separate drive means are necessary to rotate a cam, to pivot a cam follower coupled to the nozzle and to pivot a sump carrier, respectively. This also leads to relatively complex coordinating means and, therefore, all in all to a great number of individual parts necessary to perform the desired function. Moreover, should there be an interruption in hydraulic power, the nozzle and sump will not automatically return to their common storage position, and clogging will be inevitable. A spring-controlled valve, while assuring lifting of the nozzle into its storage position in a non-operating condition as long as hydraulic pressure is applied will merely move to the right by its spring force, however it cannot "urge" the nozzle or sump towards their common storage position at any time of an interruption in hydraulic power.
[0004] The object of this invention is to improve a liquid applicator apparatus of the above type in which the movement of a liquid dispensing nozzle between a clog-preventing storage reservoir and an operating position can be accomplished by a relatively simple mechanism allowing for the automatic return of the nozzle to the sump in case of any power failure.
[0005] The liquid applicator apparatus of the invention (of the type disclosed in US-A-3,709,110) is characterized in that the coupling means comprises A) a pivotally mounted cam plate carrying the sump and having a cam surface that is directly engaged by said cam member and B) a carrier on which said nozzle is mounted, said carrier having a cam surface that is directly engaged by the cam member and C) that said spring means automatically urges said nozzle and said sump towards their common storage position.
[0006] The invention and its advantages will become more apparent in the detailed description of a preferred embodiment presented below. Reference is made to the accompanying drawings, in which:
FIGS. 1-3 illustrate an embodiment of the invention in which a clog-preventing liquid sump is pivotally mounted for movement between a nozzle-storing position and a displaced position; and
FIG. 4 is a side elevation view, partly broken away, taken along line 4-4 of FIG. 3; and
FIG. 5 is a side elevation view taken along the line 5-5 of FIG. 4.
[0007] Referring now to FIGS. 1-5 of the drawings, a preferred embodiment of the adhesive applicator apparatus of the present invention is generally designated 200. The applicator 200 includes a nozzle assembly 202 which comprises a cylindrical housing 204, a nozzle tip 206 through which a liquid material, e.g. a liquid adhesive can be dispensed, and an inlet port 208 through which adhesive is supplied to the nozzle assembly. The liquid to be dispensed can be furnished to the nozzle assembly 202 from a source of pressurized material (not shown). The nozzle assembly 202 preferably includes a solenoid operated valve 210, forming part of the nozzle, which is under control of a logic and control unit LCU 211 (FIG. 2). Valve 210 controls the flow of adhesive through the applicator in response to signals from the LCU.
[0008] Nozzle assembly 202 is rigidly coupled to and supported by a plate 260 by means of a sleeve- shaped gripper 262. Plate 260 is slidably mounted between a pair of rails 224 and 226 carried by a mechanism plate 222. The plate 260 is retained in its position between rails 224, 226 by a retainer 264 that is secured to rail 226 by a fastener 266. The retainer 264 has a flange portion that overlies part of the plate 260 to prevent it from moving away from the mechanism plate 222. A lip (not shown) can be provided on the outer edge of rail 224 to limit movement of plate 260 away from plate 222. Thus the plate 260 is mounted for reciprocating movement in a vertical direction and in a plane parallel to and adjacent to the surface of plate 222. As plate 260 slides upwardly and then downwardly between rails 224 and 226, the nozzle assembly first moves from a storage position (FIG. 1) to an intermediate position (FIG. 2) and then to an operating position (FIG. 3).
[0009] When the nozzle assembly is in its storage position the tip 206 of the nozzle is located in a sump generally designated 212. As the nozzle assembly is moved from its storage position to its intermediate position, tip 206 is withdrawn from the sump. As the nozzle assembly moves from its intermediate position to its operating position, the sump is swung to the side, as described below, away from the path of movement of the nozzle assembly.
[0010] Sump 212 comprises a hollow container 214 having on the top thereof a seal 216 of rubber or similar elastomeric material. Preferably, container 214 is formed of a clear transparent material. The container holds a liquid solvent 215 (FIG. 1), such as water, for the adhesive material being dispensed through the nozzle. Thus when the tip 206 of the nozzle is in the sump 212 any material in the lower end of the nozzle will not dry out, cake or clog the end of the nozzle. By making container 214 of a transparent material the machine operator can readily determine if there is sufficient liquid in the container to cover the tip end of the nozzle. The seal 216 prevents spilling and drying of the liquid in the container. Suitable detectors (not shown), such as mechanical switches or emitter-detectors, can be used to sense the presence of the applicator at its operating position or its storage position and to provide a signal to LCU 211.
[0011] A mechanism generally designated 220 is provided for moving the sump 212 between the two positions shown in FIGS. 1 and 3. Such movement of the sump occurs simultaneously with movement of the nozzle assembly 202 between its intermediate position (FIG. 2) and its operating position (FIG. 3). Mechanism 220 comprises a cam plate 228 which is pivotally mounted on mechanism plate 222 by a pivot pin 230. The sump 212 is secured to the lower end of the cam plate 228. An opening in the upper end of the cam plate is defined by two arcuate cam follower surfaces 232 and 234 which meet adjacent to the pivot 230. An eccentrically mounted circular cam 236 fits between the cam follwer surfaces 232 and 234 with one face of the cam being adjacent the surface of the plate 222. A drive shaft 238 is journalled in a housing 240 (FIG. 4) projecting from the rear of plate 222. One end of the drive shaft 238 is connected to the cam 236 and the axis of the shaft 238 is offset from the center of the cam 236 so that rotation of the shaft is effective to cause eccentric movement of the cam about the axis of the shaft.
[0012] The end of the shaft 238 opposite from the cam has a gear 242 mounted thereon. Gear 242 is driven from a gear sector 244 that pivots about a shaft 246. The sector has an integral arm portion 248 that is connected at 250 to a rod 252 of a pneumatic cylinder 254 (FIG. 5). Thus when the cylinder 254 is supplied with air under pressure, rod 252 is extended to effect rotation of gear sector 244 and thereby rotate the gear 242 and the drive shaft 238 to turn the cam 236. When pneumatic pressure is released, a return spring in the cylinder 254 effects movement of the parts in the opposite direction.
[0013] When cam 236 is driven in a clockwise direction from the position shown in FIG. 3, the edge of cam 236 engages the cam follower surface 232 to swing plate 228 in a clockwise direction about pivot 230, thereby to bring the plate and sump 212 to the positions illustrated in FIGS. 1 and 2. When cam 236 is driven in a counterclockwise direction from the position shown in FIG. 2, the edge of cam 236 engages cam follower surface 234 to drive the plate 228 in a counterclockwise direction about pivot 230, thereby moving the plate and the sump 212 to the FIG. 3 position.
[0014] Plate 260 has a narrow slot 268 that extends horizontally across the upper end portion of the plate. A pin 270 is eccentrically mounted on the cam 236 and projects through slot 268 in plate 260. As the cam is rotated about the axis of shaft 238, pin 270 swings through an arcuate path about the axis of shaft 238 and also travels along slot 268, thereby effecting vertical reciprocating movement of plate 260 between rails 224, 226 and in a plane generally parallel to the plate 222. The applicator assembly is carried by the plate 260 and therefor also reciprocates vertically as the plate is moved. Thus the applicator assembly 202 is moved first vertically upwardly from its FIG. 1 storage position to its FIG. 2 elevated position as the cam is rotated approximately 90° counterclockwise, and then the applicator assembly is moved downwardly from its FIG. 2 position to its FIG. 3 operating position as the cam rotates an additional 180° counterclockwise. Reverse movement of the cam effects movement of the applicator assembly from the FIG. 3 position upwardly to the FIG. 2 position and then back downwardly to the FIG. 1 position.
[0015] As the cam moves counterclockwise from the FIG. 1 to the FIG. 2 position, the cam moves freely within the opening defined by cam followers 232, 234 of the cam plate 228. Therefore, the plate remains in its FIG. 1 position during such movement of the cam. Further counterclockwise movement of the cam from its FIG. 2 position causes the cam to engage the surface of cam follower 234 and thereby swing the cam plate about pivot 230 from its FIG. 2 position to its FIG. 3 position. Such movement swings the sump 212 to the right and out of the path of movement of the applicator assembly as the assembly moves from its most elevated position illustrated in FIG. 2 to its operating position illustrated in FIG. 3.
[0016] As mentioned previously, rotation of the cam 236 is effected by a pneumatic cylinder 254 which has a spring for returning rod 252 to the cylinder when pneumatic pressure is removed. As a result, the adhesive applicator assembly 202 and the sump 212 are returned from their FIG. 3 positions to their FIG. 1 positions for storage in the event of a power failure which would shut off the source of the pneumatic pressure. This is desirable because it always returns the end 206 of the applicator to the sump 212 so that adhesive in the end of the applicator will not dry out and clog the system during non-gluing operations due to power failure.
[0017] Operation of the apparatus will now be described. During the periods of non-use the nozzle tip 206 is located in the storage position illustrated in FIG. 1. At this time the nozzle tip is positioned inside the sump 212 and is covered by the liquid solvent 215 to prevent drying out or clogging of the adhesive material in the lower end of the nozzle tip. When it is desired to use the nozzle for applying adhesive, pneumatic cylinder 254 is energized with air or other gas under pressure to extend the rod 252 and thereby effect movement of the great sector 244 to rotate the drive shaft 238 in a counterclockwise direction as viewed in FIGS. 1-3. Rotation of shaft 238 drives the eccentrically mounted cam 236 in an eccentric path about the axis of shaft 238 from its FIG. 1 position through its FIG. 2 position to its FIG. 3 position. As this occurs the pin 270 travels along the slot 268 in the cam plate 228 from its extreme right position (FIG. 1), through the position shown in FIG. 2, to an extreme left position (not shown), and finally to its position shown in FIG. 3.
[0018] During initial movement of the parts from the FIG. 1 to the FIG. 2 position, cam plate 228 remains stationary while the plate 260 is lifted upwardly by movement of the pin 270 along the slot 268. Cam 236 rotates freely within the cam surfaces 232, 234 at this time without causing movement of the cam plate 228. This brings the part to the position illustrated in FIG. 2 where the nozzle tip 206 has been lifted out of the sump 212. Further rotation of shaft 238 in a counterclockwise direction causes cam 236 to engage cam follower surface 234 and thereby swing the cam plate 228, about pivot pin 230, from the FIG. 2 position to the FIG. 3 position where the sump 212 is located to the right of the path of movement of the nozzle tip 206. Promptly after the sump has been swung to the side to its FIG. 3 position and plate 260 has been raised to its uppermost position, pin 270 drives plate 260 downwardly, thereby lowering the nozzle tip 206 to its operating position shown in FIG. 3. At this time valve 210 can be opened in response to a signal from the LCU 211 to effect flow of adhesive out of the tip 206 onto a sheet of paper, for example, (not shown) as relative movement is effected between the nozzle and the sheet of paper. Such relative movement may occur by movement of the sheet of paper past the tip of the nozzle.
[0019] After application of the adhesive is completed, the air or the gas under pressure supplied to cylinder 254 is shut off to allow the return spring in the cylinder to retract the rod 252. This moves the gear sector 244 and gear 242, thereby to effect rotation of drive shaft 238 in a clockwise direction as viewed in FIGS. 1-3. During initial movement of the drive shaft in a clockwise direction from its FIG. 3 position, plate 260 is raised from its FIG. 3 to its FIG. 2 position due to movement of pin 270 in slot 268. As the plate 260 is being raised to its FIG. 2 position, the cam 236 engages cam follower surface 232 to pivot the cam plate 228 from its FIG. 3 position to its FIG. 2 position and thereby locate the sump 212 in a position immediately beneath the tip 206 of the nozzle as shown in FIG. 2.
[0020] Continued rotation of drive shaft 238 in a clockwise direction causes pin 270 to move from its FIG. 2 position to its FIG. 1 position, thereby driving plate 260 downwardly and causing tip 206 of the nozzle assembly to penetrate seal 216 and be inserted into the sump 212 to a point where it is beneath the level of the solvent 215 in the sump. Because this return movement of the parts from the FIG. 3 position to the FIG. 1 position is effected by a return spring in the cylinder 254, such return movement will be accomplished anytime there is a failure in power, etc. which is effective to shut off the supply of fluid under pressure to the cylinder 254. Thus the nozzle is always returned to the sump to prevent clogging of adhesive in the end of the nozzle in the event of inadvertent shut down of the apparatus.
[0021] The apparatus of this embodiment provides a relatively simple mechanism for moving the nozzle and sump between their respective positions and also effects return of the nozzle to the sump in case of power failure, etc. The use of the cam and cam followers, and the pin 270 and slot 268, provide positive control of the parts during movement and insures precise positioning of the parts in their operating and storage positions.
a nozzle (202) having a tip (206) through which a liquid is dispensable;
a sump (212) adapted to contain a material which prevents hardening of said liquid;
a cam member (236);
drive means (238, 270) for moving said cam member (236);
means (222, 224, 226, 260) for operatively coupling said nozzle (202) and said sump (212) to said cam member (236), which when driven provides for movement of said nozzle and sump between a common storage position in which said nozzle tip (206) is located in said sump (212) and an operating position for said nozzle for applying liquid and a standby position of said sump (212) outside the path of movement of said nozzle, respectively;
spring means associated with said nozzle (202) and said sump (212), respectively, for moving them towards a common storage position
characterized in that the coupling means comprises
(A) a pivotally mounted cam plate (228) carrying the sump (212) and having a cam surface (232, 234) that is directly engaged by said cam member (236) and
(B) a carrier (260, 262) on which said nozzle (202) is mounted, said carrier having a cam surface (268) that is directly engaged by the cam member (236) and
(C) that said spring means automatically urges said nozzle (202) and said sump (212) towards their common storage position.
- einer Düse (202) mit einer zur Abgabe einer Flüssigkeit geeigneten Spitze (206);
- einem Behälter (212), der ein das Festwerden der Flüssigkeit verhinderndes Mittel enthält;
- einem Nockenglied (236);
- Antriebsmitteln (238, 270) zum Bewegen des Nockenglieds (236);
- Mitteln (222, 224, 226, 260) zur wirksamen Kupplung der Düse (202) und des Behälters (212) mit dem Nockenglied (236), wobei beim Antrieb dieser Mittel die Düse und der Behälter zwischen einer gemeinsamen Speicherposition, in der sich die Düsenspitze (206) in dem Behälter (212) befindet, und einer Arbeitsposition, in der die Düse Flüssigkeit aufträgt, bzw. einer Warteposition, in der sich der Behälter (212) außerhalb der Bewegungsbahn der Düse befindet, bewegt werden;
- der Düse (202) bzw. dem Behälter (212) zugeordneten Federmitteln, um diese in eine gemeinsame Speicherposition zu bewegen,
dadurch gekennzeichnet, daß
(A) die Kupplungsmittel eine schwenkbar gelagerte Nockenplatte (228) umfassen, die den Behälter (212) trägt und eine Steuerfläche (232, 234) aufweist, an der das Nockenglied (236) direkt angreift.
(B) die Kupplungsmittel einen Träger (260, 262) umfassen, auf dem die Düse (202) gelagert ist und der eine Steuerfläche (268) aufweist, an der das Nockenglied (236) direkt angreift, und
(C) die Federmittel die Düse (202) und den Behälter (212) automatisch in ihre gemeinsame Speicherposition drücken.
- une buse (202) munie d'un embout (206) au travers duquel on distribue le liquide;
- un récipient (212) adapté pour contenir un matériau pour empêcher la solidification dudit liquide;
- un élément (236);
- des moyens d'entraînement (238, 270) pour déplacer ledit élément (236);
- des organes de liaison (222, 224, 226, 260) pour relier ladite buse (202) et ledit récipient (212) audit élément (236) de manière que l'entraînement de l'élément provoque le déplacement de la buse et du récipient entre une position de repos dans laquelle l'embout (206) est situé à l'intérieur du récipient (212) et une position de fonctionnement dans laquelle ledit recipient (212) n'est pas situé sur la trajectoire de ladite buse; et
- des moyens de sollicitation associés à ladite buse (202) et audit récipient (212), respectivement,
pour les déplacer vers leur position de repos, caractérisé en ce que les organes de liaison comprennent:
A - une plaque (228) basculante, portant le récipient (212) et présentant une surface (232, 234) de came directement en contact avec ledit élément (236); et
B - un chariot (260, 262) portant ladite buse et présentant une surface (268) de came directement en contact avec l'élément (236)
C - et en ce que lesdits moyens de sollicitation renvoient automatiquement ladite buse (202) et ledit récipient (212) vers leur position de repos.