Apparatus for coating of objects using a porous resilient matrix

Abstract: An apparatus (210) for applying a coating to an object (212) includes a pair of rotating members (250,270) each including a porous resilient roll mounted for counter-rotatory movement. The members (250,270) are mounted so that they contact each other during a segment of the movement and are out of contact with each other at other segments of the movement. The apparatus (210) includes a coating supply system (224) for supplying a coating to the resilient rolls (216). The rotatory movement of the members (250,270) includes a coating loading segment where the resilient rolls (216) are in physical contact and have a degree of compression with the coating supply system (224) for loading the coating into the rolls (216). The sequential movement also includes an intermediate segment where the resilient rolls are out of contact with each other and where an object (216) to be coated is movable into position for movement between the resilient rolls when the rolls are in a coating delivery segment. In the coating delivery segment, the resilient rolls (216) are in physical contact and have a degree of compression with each other and with the object (212) to be coated as the object (212) is moved between the rolls (216). The coating delivery segment serves to apply the coating to the object (212). A method for applying a coating to an object (212) includes moving an object to be coated between rotating members (250,270), each of which includes a porous resilient roll (216) mounted for counter rotatory motion to each other in a coating delivery segment of a sequential movement.

Description: Field of Invention This invention relates to the coating of objects and more particularly relates apparatus for applying lubricants to medical devices such as over-the-needle peripheral venous catheters, hypodermic needles, blades and the like. Background of the Invention Medical devices are often assembled from components formed from many different materials. It often is necessary to apply a coating of a lubricant to one or more of the components so that a component of one material will readily slide against a component of another material. Examples of this type of application are catheters with guidewires, over-needle catheters, syringe plunger stopper within a syringe barrel, needles for penetration of blood collection tube stoppers and the like. In other medical device applications, a lubricant is applied to a device to ease its penetration into the body. Examples of these applications are surgical blades, hypodermic needles, peripheral venous catheters and the like. In all of these medical device lubrication applications, there are strict requirements on the amounts of lubricant, the uniformity of the application and a need to avoid contamination of the device with foreign material other than the lubricant. A further requirement on application of lubricant results from the high volume production requirements often resulting in the use of high speed assembly equipment. Thus, any lubricant application must be precise and compatible with high volume production. Currently, a commonly used lubricant for medical devices is "silicone," i.e. polydimethyl siloxane having a Brookfieid viscosity between about 1,000 and 20,000 centistokes (cs). For some applications, the silicone is applied "neat", i.e., without solvent. An example of neat application of silicone to syringe plunger stoppers is disclosed in United States Patent 5,207,293 to Eden et al. This patent discloses a method and apparatus for lubricating syringe stoppers by moving the stoppers between a pair of wheels which are positioned partially in a reservoir containing lubricant so that with rotation of the wheels, lubricant is transferred to the stoppers. Another commonly used neat application method is tumbling a measured quantity of small parts, such as stoppers, with a measured quantity of lubricant so that the parts acquire a coating of the lubricant. Silicone lubricant also may be sprayed onto the parts either neat or diluted in a carrier solvent. Neat spraying has been found to work well for interior surfaces such as inside syringe barrels. Solvent based dipping or spraying is commonly used for coating hypodermic needles and catheters. Chlorofluorcarbon solvents have proven to be very satisfactory for the delivery of silicone onto medical devices because they are non-toxic, non-flammable, inert, evaporate rapidly without leaving residue and are available in very high purity. Unfortunately, because of the belief that chlorofluorocarbon solvents are responsible for destruction of ozone in the upper atmosphere, most commonly used chlorofluorocarbon solvents will no longer be available. Alternate solvents such as hydrocarbons are flammable, and aqueous based systems generally are not practical for silicones. Thus, there is a need for an apparatus that is compatible with high production volume and capable of uniformly delivering precise quantities of lubricant to medical devices. JP-A-6 198 233 describes a device for coating metal caps with rustproof coating material, wherein a metal cap passes through the nip between a pair of rotationally driven sponge like coating rollers in order to be coated with the material. Summary of the Invention An apparatus for applying a coating to an object comprising: a first roller mounted on a first axis for rotation thereabout, the first roller being compressible; a second roller mounted on a second axis parallel to the first axis for rotation about the second axis, the second roller being disposed adjacent said first roller; characterised in that: the first roller defines a non-compressed thickness of t 1; and the apparatus further comprises a first porous lubricating roller having an axis parallel to the first axis for rotation thereabout, the first porous lubricating roller being compressed against said first roller wherein a thickness t 2 of said first roller from the first axis to the first porous lubricating roller is less than t 1 ; means in communication with said first roller and said second roller, for moving said object to a location between the first roller and the second roller for the application of a fluid on the object wherein a distance t 3 of the first roller from the first axis to the object is less than t 1 and greater than t 2 when said object is disposed between said first roller and said second roller. In a preferred embodiment, the apparatus includes a pair of rotating members each including a porous resilient roll mounted for counter-rotatory movement. The members are mounted so that they contact each other during a segment of the movement and are out of contact with each other at other segments of the movement. The apparatus includes a coating supply system for supplying a coating to the resilient rolls. The rotatory movement of the members includes a coating loading segment where the resilient rolls are in physical contact and have a degree of compression with the coating supply system for loading the coating into the rolls. The movement includes an intermediate segment where the resilient rolls are out of contact with each other and where an object to be coated is movable into position for movement between the resilient rolls. The movement also includes a coating delivery segment where the resilient rolls are in physical contact and have a degree of compression with each other and with the object to be coated as the object is moved between the rolls. The coating delivery segment serves to apply the coating to the object. The apparatus of the present invention provides a precise coating of neat lubricant to objects such as hypodermic needles, catheters, guidewires and the like. The invention is compatible with high volume assembly and can be built into a compact station to be fit into existing assembly machinery. Brief Description of the Drawings Fig. 1 is a perspective view of an embodiment of the apparatus of the present invention; Fig. 2 is a partial cross-sectional schematic view of the apparatus of Fig. 1 along the line 2-2; Fig. 3 is a perspective view of a further embodiment of the apparatus of the present invention; Fig. 4 is a partial schematic view of the apparatus of Fig. 4 along the line 5-5. Detailed Description As shown in Figs. 1-2, an apparatus 210 is used for coating an object 212. Apparatus 210 includes a rotating member 250 with a porous resilient roll 216. Rotating member 250 rotates about a shaft 251. Rotating member 250 has a rotary movement sequence schematically illustrated in Fig. 8. The movement sequence includes a coating loading segment where resilient roll 216 is in physical contact with and has a degree of compression with a coating loading member 260. The coating loading member 260 preferably is supplied with coating by a coating supply system 224 which includes a coating reservoir 226 with a coating 227 and a coating transport system 228. The coating loading member may rotate counter to the rotation of rotating member 250 or it may be fixed, but preferably, coating loading member 260 rotates counter to member 250. Member 260 preferably is porous with the coating being supplied to a contact surface 262 of member 260 through a plurality passageways 264 supplied by transport system 228. As resilient roll 216 passes surface 262, the degree of compression may be determined by comparing uncompressed thickness t 1 with thickness t 2 where roll 216 contacts coating member 260. The t 2 /t 1 compression serves to transfer the coating to the resilient roll and spread it uniformly. Apparatus 210 preferably further includes a base 220 and a rotating support member 270 having a resilient surface 272. As resilient roll 216 rotates past coating loading member 260 the compression is released and roll 216 returns to uncompressed thickness t 1 . Apparatus 210 preferably includes an object handling system 234 for moving objects 212 to be coated between resilient roll 216 and rotating support member 270 at the coating loading segment so that resilient roll 216 is in physical contact and has a degree of compression with object 212 and surface 272 of the rotating support member in an area 213. The compression between roll 216 and object 212 transfers the coating to the object. The degree of compression between resilient roll 216 and surface 272 is shown by thickness (t 3 /t 1 ). Preferably the degree of compression in the coating loading segment is greater than the degree of compression in the coating delivery segment. As shown in Figs. 4-5, an apparatus 310 for applying a coating to an object 312 includes a pair of rotating members 350A, 350B mounted for counter-rotatory movement so that the members contact each other during one segment of the movement in an area of contact 313 and do not contact each other at other segments of the movement. Rotating members 350A, 350B rotate respectively about shafts 351A, 351B. Rotating members 350A, 350B have a rotary movement sequence schematically illustrated in Fig. 5. The movement sequence includes a coating loading segment where each resilient roll 316A, 316B is respectively in physical contact and has a degree of compression with coating loading members 360A, 360B. Coating loading members 360A, 360B may rotate counter to the rotation of rotating member 350A, 350B or the coating loading members may be fixed, but preferably, coating loading members 360A, 360B rotate counter to members 350A, 350B. Members 360A, 360B preferably are porous with the coating being supplied to contact surfaces 362A, 362B through a plurality of passageways 364A, 364B supplied by transport system 328A, 328B. As resilient rolls 316A, 316B, respectively, pass surfaces 362A, 362B, the degree of compression may be determined by comparing uncompressed thickness t 1 with thickness t 2 where rolls 316A, 316B contact coating members 360A, 360B. The compression t 2 /t 1 serves to transfer the coating to the resilient rolls and spread it uniformly into the rolls. Apparatus 310 preferably further includes a base 320 for mounting the rotating members and the coating loading members. As resilient rolls 316A, 316B rotate past coating loading members 360A, 360B, the compression is released and rolls 316A, 316B return to the uncompressed thickness t 1 . Apparatus 310 preferably includes an object handling system 334 for moving objects 312 to be coated between the resilient rolls 316A, 316B in the direction of rotation of the rolls at the position where the rolls are in physical contact with each other and have a degree of compression. This movement of the objects between the rolls causes the rolls to have a degree of compression with object 312 being coated transferring coating from the rolls to the object. Preferably, the movement of objects 312 between resilient rolls 316A, 316B is a continuous motion into and out of area of contact 313 of the rolls. The degree of compression between the resilient rolls is determined by thickness t 3 /t 1 . Preferably the degree of compassion in the coating loading (t 2 /t 1 ) segment is greater than the degree of compression (t 3 /t 1 ) in the coating delivery segment. The coating apparatus of the present invention may be compactly built to fit on assembly machines into space currently used for solvent based coating apparatus. The apparatus and method for its use demonstrate a capability to produce product having similar quality and performance properties to standard commercial product produced with solvent based coating. The apparatus of the present invention is also compatible with the assembly rate requirements and efficiency of current assembly machines using solvent based coating systems. The present invention provides a simple and reliable coating station for medical device assembly machines allowing manufacturers to eliminate the use of solvent based coating systems in many applications.

Claims: An apparatus (210,310) for applying a coating to an object comprising: a first roller (216,316A) mounted on a first axis for rotation thereabout, the first roller (216,316A) being compressible; a second roller (270,316B) mounted on a second axis parallel to the first axis for rotation about the second axis the second roller (270,316B) being disposed adjacent said first roller (216,316A); characterised in that : the first roller defines a non-compressed thickness of t 1; and the apparatus further comprises a first porous lubricating roller (260,360A) having an axis parallel to the first axis for rotation thereabout, the first porous lubricating roller (260,360A) being compressed against said first roller (216,316A) wherein a thickness t 2 of said first roller (216,316A) from the first axis to the first porous lubricating roller (260,360A) is less than t 1 ; means (234,334) in communication with said first roller (216,316A) and said second roller (270,316B), for moving said object to a location between the first roller (216,316A) and the second roller (270,316B) for the application of a fluid on the object wherein a distance t 3 of the first roller (216,316A) from the first axis to the object is less than t 1 and greater than t 2 when said object is disposed between said first roller (216,316A) and said second roller (270,316B). The apparatus of claim 1 further comprising a means (224,328A) for supplying fluid for coating the substrate to the first porous lubricating roller (260,360A). The apparatus of claim 2 wherein the second roller (270,316B) is compressible and defines a non-compressed thickness of t 1 . The apparatus of claim 3 further comprising a second porous lubricating roller (360B) having an axis parallel to the second axis for rotation thereabout, the second porous lubricating roller (360B) being compressed against said second roller (316B) and wherein a thickness t 2 of said second roller (316B) from the second axis to the second porous lubricating roller (360B) is less than t 1 . The apparatus of claim 4 wherein the distance of the second roller (316B) from the second axis to the object is less than t 1 and greater than t 2 when said object is disposed between said first roller (316A) and said second roller (316B). The apparatus of claim 5 further comprising a means (328B) for supplying fluid for coating the object to the second porous lubricating roller (360B).

Inventors: LAMBERT JEANNE E, LEE MIN SHIU, TALLER ROBERT A, WILLIAMITIS VICTOR A, LAMBERT, JEANNE E., LEE, MIN SHIU, TALLER, ROBERT A., WILLIAMITIS, VICTOR A.
Applicants: BECTON DICKINSON CO, BECTON DICKINSON AND COMPANY
Application year: 1996
Main classification: B05C1
IPC codes: A61M25, B05C1, A61M5, B05C11