Patent Abstract:
Prophylactic devices are made in an inert atmosphere by cooling mandrels on which the devices are to be deposited, dipping the mandrels into a polymeric material in a solvent/carrier and a mold release agent, rotating the mandrels during and after the dipping, and evaporating the solvent after dipping. The apparatus includes an air lock between a section in which these functions are performed and a section located in an air atmosphere for removing the devices from the mandrels, followed by cleaning the mandrels for use in a subsequent production run for making devices.

Full Description:
RELATED APPLICATION 
     This Application is related to Ser. No. 09/095,345, filed on the same day herewith, filed Jun. 10, 1998, now U.S. Pat. No. 6,106,748, entitled “Method And Apparatus For Removing Prophylactic Devices From Mandrels”, and assigned to the same Assignee as the present Application 
    
    
     FIELD OF THE INVENTION 
     The field of the present invention relates to apparatus and methods for making prophylactic devices, and more particularly to making such prophylactic devices from polyurethane. 
     BACKGROUND OF THE INVENTION 
     Prophylactic devices are used to prevent the transfer of infection, bacteria and viruses from an environment to a body member on which the device is mounted. Prophylactic devices include but are not limited to catheters, valves, gloves, and so forth. For example, condoms are used to protect the user from venereal diseases and for birth control, and surgical gloves are used to protect the user from infection. In order to allow the protected body member to move freely and to respond to external stimulus, the device must be as thin as possible, but this reduces the protection it provides. For many years prophylactic devices have been made of latex rubber, but when a latex condom is sufficiently thin, it reduces overall strength, is subject to breakage, and there is an increased risk that it will have pin holes that are large enough to permit the passage of viruses such as the HIV. Accordingly, latex condoms must be manufactured and tested with great care and consequent expense. Also, some people are allergic to latex. 
     It has been found that prophylactic devices made of polyurethane, in contrast to latex, can be very thin so as to provide a good sense of feel while at the same time being very strong, and free from pinholes. Also, polyurethane due to its synthetic nature is typically more nonallergenic than latex. 
     In U.S. Pat. No. 4,684,490 a method for manufacturing condoms is described in which a mandrel having the general shape and dimensions of a condom is dipped into a solvent solution of a polyurethane polymer and heated in air after being withdrawn therefrom so as to dry the polyurethane. The dried polyurethane which now forms a condom is then removed from the mandrel. 
     SUMMARY OF THE INVENTION 
     In accordance with the overall method used in this invention, mandrels having the general shape of the prophylactic device being manufactured are cleaned and subjected to cooling before being dipped into polyurethane or other suitable polymers dissolved in tetrahydrofuran (THF) for example. Other solvents or carriers such as dimethylfluorene (DMF), methyl ethyl ketone (MEK), dimethyl sulfoxide (DMSO), dimethylacetimide (DMAC), alcohols, chlorinated hydrocarbons, ketones, ethers, water (H 2 O), or any other organic solvents known in the art, and blends of such solvents, can also be used. THF is preferred for use in this invention partly because of its high solubility and easy removal or release from the finished film. 
     After dipping, the mandrels are rotated so as to produce a uniform film of a desired thickness profile and subjected to an elevated temperature so as to drive off the solvent. In a preferred method, the process is repeated starting with progressive cooling, followed by a second dip so that a second film of polyurethane is formed with the first film on the mandrel. The two films tend to become homogenous. Since THF tends to be highly flammable and potentially explosive in an oxygen atmosphere, the steps just described are carried out in a pressurized explosion resistant atmosphere maintaining oxygen below levels to support combustion. 
     The invention also includes a system for carrying out the aforesaid method in which pallets having mandrels mounted therein are transported through cleaning stations before being transported through a plurality of progressive cooling chambers to a dipping chamber in which there is a reservoir of polyurethane material dissolved in tetrahydrofuran. The viscosity of the solution is maintained in a desirable range by mixing or agitating it at a controlled temperature and keeping the concentration of THF within a given range. It is important that the rate at which the mandrels are lowered into and raised from the solution be precisely controlled, smooth and that there be no vibration. The pallets of mandrels are then rotated as much as 360° about an axis in the plane of the pallet, first in the dipping chamber, and then in a rotation chamber. Bidirectional rotation may be used in some applications. While in these chambers the mandrels themselves are also rotated about their respective axes. The polyurethane film formed on the mandrels by their having been dipped into the polyurethane solution is dried in evaporation ovens at successively higher temperatures, respectively. After the pallets emerge from the last evaporation oven, they are preferably subjected to a repeat of the process just described for a second dipping of the mandrels. 
     After this is done, the pallets are transported to a series of stations in an air atmosphere that respectively form one or more permanent rings at the open ends of the condoms on the mandrels, apply powder and remove the condoms from the mandrels. Alternatively, a wet takeoff system can be used. The pallets of mandrels freed of condoms are washed in one station, and rinsed in another, before being transported via a staging conveyor to an inspection and redress station. After completion of the inspection and redress, the pallets and mandrels are transported to a drying oven station. After drying, the pallets and associated mandrels are ready to be passed through the chambers just described starting with the cooling chambers, for another cycle making condoms. 
     Because of the high flammability and explosiveness of the solvent, THF, means are provided for keeping the oxygen concentration below given levels in each of the chambers referred to by introducing N 2 , and operating with the THF in a substantially oxygen free atmosphere. The expense of the operation is reduced by recovering THF from the atmosphere expelled from the chambers by utilizing a closed-loop system that passes through a condensing or absorption system. With this process the N 2  is reused, and heat exchangers are employed for extracting heat for use in the process. In this manner, through recovery of THF, N 2 , and heat, the process is made highly economic, and environmentally friendly. Also, any imperfect polyurethane condoms can be recycled back into the system. 
     Since the stations in the section where the final product is removed from the mandrels, and the mandrels are cleaned, inspected, redressed, and dried, respectively, are in the ambient or air atmosphere containing oxygen, and the chambers in the section where the product is formed on the mandrels in a nitrogen and oxygen reduced atmosphere, the mandrels are passed from one section to the other via an air lock. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments of the present invention are shown and described herein with reference to the drawings, in which like items are identified by the same reference designation, wherein: 
     FIGS. 1A and 1B are block diagrams of the principal components of apparatus for making prophylactic devices in accordance with the invention; 
     FIGS. 1C,  1 D,  1 E, and  1 F respectively illustrates the manner in which the elevator shown in FIG. 1A operates to position pallets for transfer between different parts of the apparatus; 
     FIG. 2 is a flowchart of the steps in making a prophylactic device in accordance with the invention; 
     FIG. 3 is a block diagram of apparatus used to control the temperature, percent O 2  and percent solvent in various chambers of the apparatus of FIG. 1; 
     FIG. 4A illustrates an elevator and mechanism for rotating the pallets as well as the mandrels; 
     FIG. 4B is a bottom view of a pallet carrying mandrels; 
     FIG. 4C is pictorial and side elevational view of a glass mandrel with an electrically conductive coating, as mounted on a mandrel holder for one embodiment of the invention; 
     FIG. 4D is a bottom view of a pallet showing intermeshed gears for rotating the mandrels about their respective axes; 
     FIG. 5 is a partial pictorial view of a takeoff station for one embodiment of the invention; 
     FIG. 6 is a top view within the takeoff station of FIG. 5, looking down on a top shoe shifting plate, and opposing pairs of top plate and bottom plate shoes, respectively; 
     FIG. 7 is a top view of a bottom shoe shifting plate containing a plurality of bottom plate shoes designated as left-hand shoes; 
     FIG. 8 is a top view of a top shoe shifting plate with a plurality of top plate shoes designated as right-hand shoes; 
     FIG. 9 is a top view of an insert table containing a plurality of takeoff inserts for the takeoff station of FIG. 5; 
     FIG. 10 is a top view of a air nipple table including an air nipple assembly containing a plurality of individual air nipples, for the takeoff station of FIG. 5; 
     FIG. 11 is a side view of a portion of the assembly of the top and bottom shifting plates, and associated gear assemblies for moving the plates in a reciprocal manner to move pairs of the left-hand- and right-hand shoes either toward one another or away from one another; 
     FIG. 12A is a partial pictorial view of the assembly of FIG. 11 viewed from a different direction; 
     FIG. 12B is a side view of a portion of rack pinion gear mechanism for providing reciprocal and opposite movement between the top and bottom shoe shifting plates, respectively, for an embodiment of the invention; 
     FIG. 12C shows a top view of a portion of the gear mechanism of FIG. 12B; 
     FIG. 13 is a partial pictorial view of a portion of the takeoff insert table in association with air assist cylinders and power driven gearing for raising and lowing the insert table, and further shows a portion of the associated air nipple assembly for the takeoff mechanism of FIG. 5; 
     FIG. 14 is an enlarged pictorial view of a portion of an array of takeoff inserts relative to associated air nipples for the takeoff mechanism of FIG. 5; 
     FIG. 15 is a partial pictorial view of various gearing, motor, and air valve mechanism associated with the takeoff mechanism of FIG. 5; 
     FIG. 16 shows a top view of a shoe assembly in a closed position relative to an associated mandrel; 
     FIG. 17 is a detailed partial cross-sectional view of a mandrel carrying a condom with a pair of opposing shoes in a closed position just after partially rolling a condom for removing the condom from the mandrel; 
     FIG. 18 is a partial pictorial view showing a substantial portion of a mandrel  178  carrying a condom, with the associated shoe assembly in a closed position as in FIG. 17 for removal of the condom; 
     FIG. 19 is a pictorial view showing a mandrel carrying a condom with the associated shoes in an open position, with the open position being exaggerated for purposes of illustration; 
     FIG. 20 is a partial pictorial view of a “snapper assembly” in relation to portions of the takeoff mechanism of FIG. 5, whereby the X-Y snapper assembly is moveable relative to the takeoff mechanism; 
     FIG. 21 is a partial pictorial view showing additional portions of the X-Y snapper mechanism of FIG. 20 in conjunction with a portion of the takeoff mechanism of FIG. 5; 
     FIG. 22A is an enlarged view of a portion of the X-Y snapper assembly showing details of the suction nozzle assembly thereof; 
     FIG. 22B is a detailed view of the front of an individual suction nozzle of FIG. 22A; 
     FIG. 23 is a partial pictorial and partial sectional view of an individual air nipple assembly; 
     FIG. 24 is a top view of an air nipple of the air nipple assembly of FIG. 23; 
     FIG. 25A is a backside view of a shoe assembly for the takeoff mechanism of FIG. 5; 
     FIG. 25B is a top view of the shoe of FIG. 25A; 
     FIG. 26A shows a back view of a shoe bracket for a top plate shoe or right-hand shoe; 
     FIG. 26B shows a side view of the shoe bracket of FIG. 26A; 
     FIG. 27A shows a back view of a shoe bracket for a bottom plate shoe or left-hand shoe; 
     FIG. 27B shows a side view of the shoe bracket of FIG. 27A; 
     FIG. 28A shows a simplified partial pictorial view of a dipping solution tank having a sliding cover in an open position for permitting glass mandrels to be dipped into the tank; and 
     FIG. 28B shows the pictorial view of FIG. 28A with the sliding cover moved to a position to close off holes in the top of the tank to avoid unnecessary evaporation of the dipping solution when not in use. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The making of prophylactic devices in accordance with the method of this invention is best explained by the following description of apparatus of the invention that operates in accordance with the method. Although the method could be used to make any prophylactic device, the apparatus will be described in connection with the manufacture of condoms. 
     The complete method is a closed loop in which mandrels  178  (see FIGS. 4B,  4 C and  5 ) generally shaped like condoms are carried by pallets  176  from cleaning and drying stations to be described that are in a Section 2 (see FIG. 1A) to a succession of chambers in a Section 4 (see FIG. 1B) where at least one polyurethane film is formed on the mandrels  178 . Then the pallets  176  are returned to stations in the Section 2 in which the film on each mandrel  178 , which now has a condom with a permanent ring formed at its open end, is powdered and removed in a dry process, or removed using a wet process. The mandrels  178  are then cleaned, inspected and redressed, if necessary to replace a defective mandrel  178  or strip-off a condom not previously removed. The mandrels  178  are then ready for reuse in producing condoms. 
     As will become clear, the Section 2 where the mandrels  178  are cleaned and the condoms removed contains an air atmosphere, and the Section 4 where the film is formed on the mandrels contains an inert atmosphere including the solvent used in the film forming process. Preferably, the solvent is THF. The reason is that through experiments, the present inventor found THP to have excellent solubility for polyurethane, relative to other solvents, and it is easily removed from polyurethane. It is important to insure that all solvent is removed from the condom. Because of the explosive nature of THF, the infiltration of air from the Section 2 to the Section 4 must be minimized, and because of the flammability of the THF, its infiltration from the Section 4 to the Section 2 must be minimized even though pallets  176  of mandrels  178  are passed in both directions between the two sections. Minimizing these infiltrations is accomplished by an air lock  6  (see FIG. 1B) between the cleaning and product removal Section 2 and the film forming Section 4. 
     Note that the present invention provides a system that is capable of manufacturing prophylactic devices consisting of natural and synthetic elastomers. For example, as indicated polyurethane is such as material, as is latex. Other water-based polymers may  1  include nitrite rubber, neoprene rubber, SBS rubber emulsion, polyvinyl alcohols, polyvinyl acetate, polyacrylates, polyethylene glycols, and alkyl cellulose. Other solvent based polymers may include polyisoprene, SBS rubber, silicone rubber, polyolefms, polyamides, polyesters, PVC, polymethylmethacrylate, polyacrylates, polyacetals, polycarbonates, polycaprolactams, and halogenated polymers. Note that the water-based polymer examples are also soluble in solvents. Other polymer materials may also include copolymers, terpolymers, block polymers, and so forth. 
     The following description of the operation of the system of FIG. 1B starts with the transfer of a pallet  176  of mandrels  178  from an airlock  6  to an elevator chamber  8 . In a manner to be explained in the discussion of FIGS. 1B,  1 C,  1 D and  1 E, the pallet  176  is transported so as to spend successive periods of time isolated in a first cooling chamber  10 , a second cooling chamber  12 , a third cooling chamber  14 , a dipping chamber  16  where the mandrels  178  are coated with a polyurethane film, a rotation chamber  18 , a first evaporation oven chamber  20 , a second evaporation oven chamber  22  and back to the elevator chamber  8 . At this point, one polyurethane film has been deposited on the mandrels  178  so that the pallet  176  could be passed back through the air lock  6  into the Section 2 where the condoms are removed and the mandrels  178  are cleaned in preparation for another trip through the condom forming Section 4 as just described. Preferably, however, a second polyurethane film is formed on the first film by repeating the trip just described, in which event the pallet  176  is conveyed by an elevator in the elevator chamber  8  back to the first cooling chamber  10 . In the same manner layers of more than two films can be formed. Through use of multiple dip capabilities, the present invention provides relative to the prior art faster overall cycle times and minimizes defects. In certain product applications more than two films may be formed on each mandrel  178 . 
     A detailed description of the apparatus and operations carried out in the various chambers of the film forming Section 4 is as follows. In order to ensure that the mandrels  178  are smooth and can be readily cleaned and stripped they are made of non-porous material such as glass. In an alternative embodiment, the mandrels  178  can be frosted or etched to enhance removal of the film. Note that the mandrels can also be made from any other suitable material, not limited to glass. When they enter the first cooling chamber  10  for the first time, they will be hot because of having been passed through a drying station  100  (see FIG. 1A) in the Section 2, and when they enter it a second time, they are hot because of having come from the second evaporation oven chamber  22 . Because the temperature of the polyurethane solution into which the mandrels  178  will be dipped in the dipping unit chamber  16  in either case is kept at about 50° F. to 70° F., there is a chance that the mandrels  178  will crack, and/or excessive outgassing of the solvent will occur, if the mandrels  178  are at a temperature higher than about 58° F. In order to prevent this from occurring, the pallets  176  of mandrels  178  spend successive periods of time in the cooling chambers  10 ,  12  and  14  that are preferably at successively lower temperatures. Means not shown such as conventional heat exchanger configurations through which water or refrigerant of a proper temperature is circulated are provided for maintaining the cooling chambers  10 ,  12  and  14 , respectively, at appropriate temperatures between the temperature of the drying station and the temperature of the dipping chamber  16 , which is at about 70° F. An adjustable high velocity and even flow of air is maintained in the cooling chambers  10 ,  12  and  14 , by circulation of air in them through respective honeycombed structures  23 ,  25  and  27  in their bottoms with blowers  29 . Note that the air flow is adjustable throughout Section 4. 
     When a pallet  176  is passed from the last cooling chamber  14  into the dipping chamber  16 , it engages a dual axis robotic mechanism that is capable of vertical and rotational movement, simplistically shown in FIG. 4A, that dips the pallet  176  at carefully controlled rates of speed and without vibration into and out of a reservoir  36  of polyurethane material dissolved in THF. 
     A level control mechanism  38  senses when the level of the polyurethane solution in the reservoir  36  drops below a given level and pumps more polyurethane solution into the reservoir  36  from a tank  40 . Circulation of the solution so as to keep it homogeneous and free from particulate matter is achieved by a filter  42  and a pump  44 . In order to obtain consistent results, the viscosity of the solution in the reservoir  36  is kept constant by sensing the viscosity in the circulation loop with a viscosity sensor  47  and causing an appropriate amount of THF to be injected from a tank  46  into the circulation line with a pump  48 . It is also necessary to maintain the temperatures of the polyurethane solution constant with a suitable temperature control means  50 . The temperature of the polyurethane solution is typically 50° F. to 70° F., with the concentration of THF maintained at 3% to 7% in the atmosphere of chambers  16  and  18 . 
     Both uniformity and the profile of the thickness of a film of polyurethane solution on the mandrels  178  is significantly improved by rotating the pallet  176  about a horizontal axis by as much as 360°. Whereas the mandrels  178  can also be rotated about their respective axes both in a clockwise and counterclockwise direction in the dipping reservoir chamber  16 , chamber  18 , and evaporation ovens  20  and  22 . This is preferably done simultaneously in the dipping chamber  16  and rotation chamber  18  along with rotation of the pallet  176 . The axial mandrel  178  rotation is controlled at speeds up to one hundred rpm, and the 360° pallet  176  rotation is controlled to speeds up to six rpm. 
     Evaporation of the THF solvent in the film deposited on the mandrels  178  in the dipping solution reservoir chamber  36  so as to form polyurethane condoms on the mandrels is achieved in the dipping and rotation chamber  16 , rotation chamber  18 , and evaporation oven chambers  20  and  22 . Circulating air for the oven chambers  20  and  22  is respectively provided by blowers  52  and  54 . Air circulation in chambers  16  and  18  is provided by a common blower  53 . Evenly controlled flow is achieved by causing the air to flow downwardly along the outside surfaces of the oven chambers  20 ,  22  which are equipped with heat exchangers (not shown), and upwardly through their center through honeycombed structures  56  and  58 , respectively. 
     Accordingly, in the illustrated embodiments of the invention provided herein evaporation is used to drive THF from the film. However, with polyurethane film formula structures water quenching or stripping can also be used rather than evaporation to remove the THF from the film formed. 
     For optimum operation, the temperature and THF concentration in the chambers  8 ,  10 ,  12 ,  14 ,  16 ,  18 ,  20  and  22  must be maintained within appropriate ranges, and for safe operation, the concentration of O 2  in these chambers is maintained at sufficiently low levels. In order to reduce cost, the solvent THF is recovered. One way of performing these functions is to use apparatus such as shown in FIG. 3 for each chamber of film forming Section 4, herein designated as  61 , for representing each independent chamber. All of the aforesaid temperatures are interdependent, along with the dipping speed, dipping times, rotational speeds of mandrels  178 , withdrawal and insertion rates, angular positions, velocities, and so forth. For example, in one embodiment oven  20  is maintained at 120° F., oven  22  at 140° F., cooling station  10  at 40° F., cooling station  12  at 42° F., cooling station  14  at 41 ° F., and dipping and rotation stations  16  and  18  at 60° F. 
     The required low concentration of O 2  is secured by using detectors  62  (see FIG. 3) to constantly sample gas from the chamber  61  via tubes  64  and provide an indication to a controller  66  of the concentration of O 2 . When an indication of too high a concentration occurs, the controller  66  causes an inert gas such as N 2  from a source  68  to be introduced into the chamber  61  via a tube  72  until a sufficiently low concentration of O 2  is indicated. This is the source of N 2  that will be found in all the chambers of the film forming Section 4. Note that the O 2  detection systems are redundant throughout the present system. 
     The following table suggests the maximum concentrations of the solvent, THF, that preferably should be maintained in the various chambers. The maximum values attainable in the below listed zones 3 and 4 (see Table 1) may be limited as necessary to prevent solvent condensation on equipment within each zone. 
     
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 ZONE 
                   
                 SOLVENT 
               
               
                 NO. 
                 ZONE 
                 CONCENTRATION 
               
               
                   
               
             
             
               
                 (1) 
                 Elevator chamber 8 
                 Less than 1% THF 
               
               
                 (2) 
                 Cooling chambers 10, 12, 14 
                 Less than 1% THF 
               
               
                 (3) 
                 Dipping chamber 16 and pallet rotation 
                 1-11% THF 
               
               
                   
                 chamber 18 
               
               
                 (4) 
                 Solvent evaporation oven 20 
                 1-11% THF 
               
               
                 (5) 
                 Solvent evaporation oven 22 
                 Less than 2% THF 
               
               
                   
               
             
          
         
       
     
     In order to establish and maintain the THF concentrations set forth in Table 1, solvent sensors  74  (see FIG. 3) provide signals to the controller  66  indicative of the THF concentration in the chamber  61 . The controller  66  modulates return valves (not shown) from the recovery system and controls N 2  return from the source  78  into the chamber  61  via the tubes  72  until the THF concentration is reduced to or maintained at the the desired level. The gasses expelled from the chamber  61  via a tube  76  are transported to a means  78  for recovering the THF, which may be a BRAYCYCE® solvent recovery system, for example. The THF recovered is delivered to the tank  46  of FIG.  1 B. The heat generated by the process in the recovery system is made available for heating fluid flowing in the heat exchangers, not shown, of the evaporation oven chambers  20  and  22 , and drying oven  100 , chamber  114 , wash tank  94 , and rinse tank  96 . Note that solvent laden N 2  from the process is transferred from chamber  61  to THF recovery source  78 . The solvent is condensed out, and the process N 2  is transported back to chamber  61  via tubes  72 . 
     If it is desired to gain access to the film forming Section 4, the controller  66  operates pump  44  (see FIG. 1B) to pump dipping solution from reservoir  36  into evacuation tank  45 . The atmosphere of Section 4 is then recirculated through the solvent recovery system  78  until solvent or THF levels are reduced to acceptable levels. Next, filtered atmospheric air is introduced via air supply fan  71  (see FIG. 3) into Section 4 to bring oxygen levels to a safe level for human entry. This is done for all chambers of Section 4. 
     The temperature of a chamber generally designated as  61  is controlled by sensing the temperature of the chamber  61  with a means in a temperature control  80  that sends a signal to the controller  66 . As the temperature varies about a desired value, the controller  66  causes the temperature control  80  to vary the amount of cooling/heating fluid flowing through heat exchangers  84  that are in the air recirculation stream of chamber  61 , that is in each chamber of Section 4, respectively. 
     Section 2 
     When a pallet  176  of mandrels  178  has been fully processed in the film forming Section 4, it is transferred from the elevator station  8  to the air lock  6  and is then transferred directly to the lower level  83  (see FIG. 1A) of a robotic transport unit  85 . The transport unit  85  is successively positioned over stations  86 ,  88 ,  90 ,  94  and  96 . At each station the transport unit lower level  83  is lowered so that the function of the station can be carried out. 
     In FIG. 1A, the transport unit  85  is shown as being in registration with the station  86  wherein the open ends of the condoms on the mandrels are rolled down a short distance to form rings. The rings are permanent, and can be made so in different ways known in the art other than by rolling. For example, by gluing, bonding, sewing, or extruding a ring on the condom. However, in this example, as indicated, the ring is formed by partially rolling the open end of the unpowdered condom to form the ring, which becomes permanent because the material bonds to itself at this time. The condoms are powdered in the station  88  and removed from the mandrels  178  in the station  90 , and via the X-Y snapper station  92  the condoms are removed from the takeoff station  90 . The condoms are collected and placed into a tumbler apparatus at station  93  to permit the condom material the additional time necessary to obtain sufficient crystallization for obtaining winkle free condoms. The tumbler apparatus (not shown) can be clothes dryer or washer modified for tumbling the condoms at ambient temperature. The mandrels  178  are washed in the station  94  by soaking them in an ultrasonically activated cleaning solution or R.O (reverse osmosis) water, and rinsed in the station  96  with hot R.O water. R.O water is used to avoid environmentally sensitive discharges as would be experienced with deionized water systems and regeneration of the same. Although R.O water is preferred for use in the cleaning process, tap and/or deionized water can also be used. 
     The pallet  176  of rinsed mandrels  178  is moved onto a staging conveyor  97  which conveys the pallet  176  to an inspection and redress station  99 . The mandrels  178  that may be defective are replaced, and condoms or condom fragments if any are removed from the mandrels  178 . The redressed pallet  176  is then conveyed from the redress station  99  to the drying oven  100 , and then to level  87  of the transport unit  85 . Note that the inspection and redress station  99  can also be used to change a pallet  176  of mandrels  178  to make a different style of condom or product, or remove a defective pallet  176  on the fly. 
     The temperature in the oven  100  is regulated by a temperature controller section  104  included in controller, in this example, preferably between 160° and 180° F. Dry make-up air is drawn from a source  106  and through a filter  108  by fans  110  and with recirculated air directed upwardly through a honeycomb structure  112  just below the bottom  98  of the oven  100 . In order to obtain consistent drying, the relative humidity in the oven  100  is controlled by automatic modulation of the exhaust air flow, by measuring the humidity and opening an exhaust damper to expel moisture laden air. The space over the stations  86 ,  88 ,  90 ,  92 ,  94  and  96  is enclosed as indicated at  114 , and the temperature therein is removed by forced ventilation with a fan  116  that draws air through a filter  118 , and through heat exchanger  117 , and expelled by two exhaust fans (not shown) on each end of the chamber  114 . 
     The transport unit  85  removes pallet  176  of the dried mandrels  178  from oven  100  on its upper level  87 , and transports pallet  176  to air lock  6 , for reintroduction into Section 4, after removing a pallet  176  from air lock  6  to level  83  of the transport unit  85 . The pallet  176  and associated mandrels  178  are then moved through the various stations of Section 4 to form condoms on the mandrels  178 , as previously described. 
     When the system of FIGS. 1A and 1B is in normal operation, twelve pallets  176  are being processed at various stations and chambers. In other embodiments, more or less pallets  176  may be provided. A pallet  176  that is in the drying oven  100  can be replaced or accessed if necessary by opening a door  120  without interrupting the operation of the system. This is a less preferred access than that provided by the inspection and redress station  99 . 
     The sequence of operation of the system of FIG. 1A as set forth in FIG.  2  and in the Table 2 below, is controlled by the controller  66 . Table 2 shows a time sequence of events occurring in FIG. 1B, and is a practical example, not meant to be limiting. Because this system is programmable, and fully multitasking, flexibility is provided to adapt to other processes and/or cycle times with minimum physical modifications. 
     
       
         
               
               
               
               
             
               
               
               
               
             
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Preferred 
                 Range 
               
               
                   
                 Event 
                 (In Seconds) 
                 (In Seconds) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 (1) 
                 Transfer from drying oven 100 to air 
                 40 
                 30- 50  
               
               
                   
                 lock 6 
               
               
                 (2) 
                 Air lock 6 cycle to purge air and 
                 80 
                 60- 120 
               
               
                   
                 introduce nitrogen 
               
               
                 (3) 
                 Transfer from air lock to cooling 
                 10 
                 7- 20 
               
               
                   
                 chamber 10 
               
               
                 (4) 
                 To cooling chamber 10 
                 90 
                 80-120 
               
               
                 (5) 
                 To cooling chamber 12 
                 90 
                 80- 120 
               
               
                 (6) 
                 To cooling chamber 14 
                 90 
                 80-120 
               
               
                 (7) 
                 First dip in dipping unit chamber 16 
                 85 
                 70-120 
               
               
                 (8) 
                 Rotate and distribute film in rotation 
                 70 
                 60- 120 
               
               
                   
                 chamber 18 
               
               
                 (9) 
                 Dry film in oven chamber 20 
                 90 
                 80-120 
               
               
                 (10) 
                 Dry film in oven chamber 22 
                 90 
                 80-120 
               
               
                 (11) 
                 Transfer in elevator chamber 8 to air 
                 20 
                 15- 25  
               
               
                   
                 cooling chamber 10 
               
               
                 (12) 
                 To cooling chamber 10 
                 90 
                 80- 120 
               
               
                 (13) 
                 To cooling chamber 12 
                 90 
                 80-120 
               
               
                 (14) 
                 To cooling chamber 14 
                 90 
                 80-120 
               
               
                 (15) 
                 Second dip in dipping chamber 16 
                 85 
                 70-120 
               
               
                 (16) 
                 Rotate and distribute film in 
                 70 
                 60- 120 
               
               
                   
                 chambers 16 and 18 
               
               
                 (17) 
                 Dry film in oven chamber 20 
                 90 
                 80-120 
               
               
                 (18) 
                 Dry film in oven chamber 22 
                 90 
                 80-120 
               
               
                 (19) 
                 Transfer to air lock chamber 6 
                 20 
                 15-25  
               
               
                 (20) 
                 Air lock 6 opened to air 
                 80 
                 60-120 
               
               
                 (21) 
                 Discharge from air lock 6 onto 
                 10 
                 7- 20 
               
               
                   
                 transport unit 95 
               
               
                 (22) 
                 Form ring roll, station 86, and 
                 30 
                 20- 80  
               
               
                   
                 transfer to powder station 88 
               
               
                 (23) 
                 Powder application and transfer to 
                 20 
                 10- 80  
               
               
                   
                 takeoff station 90 
               
               
                 (24) 
                 X-Y snapper 92 removal of finished 
                 30 
                 20- 120 
               
               
                   
                 product from takeoff station 90, and 
               
               
                   
                 transfer of mandrels 178 to wash 
               
               
                   
                 station 94 
               
               
                 (25) 
                 Wash mandrels 178 in station 94 and 
                 25 
                 15- 45  
               
               
                   
                 transfer to rinse station 96 
               
               
                 (26) 
                 Rinse in station 96 
                 25 
                 15-45  
               
               
                 (27) 
                 Transfer to staging conveyor 97 for 
                 10 
                 7- 15 
               
               
                   
                 conveyance to inspection and 
               
               
                   
                 redress station 99 
               
               
                 (28) 
                 Redress 
                 180  
                 120-240  
               
               
                 (29) 
                 Transfer to drying oven 100 and 
                 10 
                 7- 15 
               
               
                   
                 transport unit 95 
               
               
                 (30) 
                 Air dry mandrels 178 in drying oven 
                 180  
                 160- 240  
               
               
                   
                 100 
               
             
          
           
               
                 PREFERRED GRAND TOTAL . . . 1,980 SEC. 
               
               
                 (33 min or 11 pallets × min./cycle) 
               
               
                   
               
             
          
         
       
     
     Operation of Air Lock 
     The air lock  6 , FIG. 1B, is provided with what is called an air side door  121  opening into Section 2, which, it will be recalled has normal air atmosphere. Air lock  6  also includes a nitrogen side door  122  opening into the elevator chamber  8  of Section 4, which, as previously mentioned can have a nitrogen or other inert atmosphere with a slight concentration of THF. 
     A pallet  176  of clean mandrels  178  from the Section 2 is passed into the film forming Section 4 by opening the air side door  121 , moving the pallet  176  into the air lock  6  and closing the air side door  121 , the nitrogen side door  122  being closed. A vacuum pump  123  pumps the air lock  6  down to a deep vacuum that is preferably less than 12 torr, which is less than 1% of the average atmospheric pressure, in order to minimize air (oxygen) infiltration into the Section 4. Air from the pump  123  exits at  127 . The vacuum is then broken by permitting nitrogen to flow into the air lock  6  from a receiver tank  126  or any suitable source, thereby equalizing its pressure with that in Section 4. The nitrogen side door  122  is then opened and the pallet  176  is passed into an elevator mechanism (not shown) in the elevator chamber  8 . 
     A pallet  176  can be passed from the film forming Section 4 to the Section 2 by passing it from the elevator section  8  into the air lock  6 . The nitrogen side door  122  is then closed, and vacuum pump  124  pumps the air lock  6  to less than  12  torr vacuum, but preferably sends its exhaust into a receiver tank  126  rather than existing into the atmosphere via outlet  125 . The vacuum is broken by connecting the air lock  6  to a source  128  of dry filtered air, the air side door  121  is opened and the pallet  176  is passed onto the lower level  83  of the transfer or transport unit  85 . The purpose of the receiver tank  126  is to conserve nitrogen because it can be the source of nitrogen when vacuum in the air lock  6  is to be broken by admitting nitrogen into it. 
     Elevator 
     The elevator in the elevator chamber  8 , not shown in detail in FIG. 1B, has two shelves  130  and  132  that are spaced by half the equal heights of the air lock  6 , the evacuation oven chamber  22  and the cooling chamber  10 . When the shelves  130  and  132  are in the positions shown in FIG. 1B, a finished pallet  176  can be moved from the oven chamber  22  onto the elevator shelf  130 , and a new clean pallet  176  can be moved from the air lock  6  onto the shelf  132 . In FIG. 1C, the finished pallet  176  can be moved from the shelf  130  to the air lock  6 . In FIG. 1D, the new pallet  176  can be moved from the shelf  132  to the cooling chamber  10 . If a pallet  176  is to be recycled so as to form a second polyurethane film on the mandrels  178 , the shelf  130  is placed even with the bottom of the oven chamber  22  (see FIG.  1 E), and the pallet  176  in the oven chamber  22  is moved onto it. Then the elevator lowers the shelf  130  to the bottom of the cooling chamber  10  (see FIG. 1F) so that the pallet  176  can be placed in that chamber a second time. Note that FIGS. 1B through 1F are not drawn to scale or in perspective, and are meant for purposes of illustration only. 
     Rotation 
     In each of the dipping unit chambers  16  and rotation chamber  18 , the dipping solution reservoir  36 , and evaporation oven  20 , the mandrels  178  are rotated about their axes. In chambers  16  and  18  the mandrels  178 , as well as the pallets  176  in which they are mounted are rotated about an axis in their planes. One way of achieving these rotations in the dipping chamber  16  as well as performing the dipping function is illustrated in FIG.  4 A. These rotations produce walls of desired thickness profiles in the prophylactic devices formed on the mandrels  178 . 
     In FIG. 4A, a chain  134  is mounted about upper and lower sets of sprockets  136  and  138 , and a chain  140  is mounted about upper and lower sets of sprockets  142  and  144 . The sprockets  136 ,  138 ,  142  and  144  are mounted on the walls of the chamber  16  for moving a robot  141  in a vertical plane, and the shafts plans  146 , driven by an electric motor  148  that is also mounted on a wall of chamber  16  is connected between the centers of the sprocket sets  136  and  142  so as to be able to rotate them. 
     Gear  150  is secured to the elevator platform  154  in such manner that it does not rotate. The elevator platform  154  is mounted for rotation about the center of gear  150  by a chain about gear  150  driven by a motor  156  and a gear set (not shown). In this example, the motor  162  is affixed to the platform  154 . The motor  162  has a vertical shaft  166 . Motor  164  is also affixed to the platform  154  and turns roller sets  172  and  174 . Projections  168  and  170  extend downwardly from the platform  154  and have powered roller sets  172  and  174 , respectively, driven by motor  164 , mounted on them. A pallet  176  that is shown as being mounted on the rollers  172  and  174  has mandrels  178  extending downwardly from it as shown in the bottom view of FIG.  4 B. As will be described in connection with FIG. 4C, gears  208  are coaxially mounted on the upper ends of the mandrels  178  that are intermeshed in such manner that rotation of one gear  208  rotates all the others. One gear  208  is rotated by engagement with the shaft  166  of the motor  162 . In order to permit the pallet  176  to be moved in and out of the chamber  16 , it is necessary that provision be made for vertical movement of the shaft  166 . Rotation of the gear sets  136 ,  138 ,  142  and  144  by operation of the motor  148  raises or lowers the entire assembly  141  between chains  134  and  140 . The assembly  141  is lowered when the mandrels  178  are to be dipped into the dipping solution reservoir  36 , and is raised when the pallet  176  and mandrels  178  are to be rotated. It is also raised when a pallet  176  and its attached mandrels  178  are to be transferred to the rotation chamber  18 . 
     When the pallet  176  is in position, it can be raised or lowered by raising and lowering the platform  154  by operation of the motor  148 . Rotation of the pallet  176  about an horizontal axis is effected by turning motor  156  and its gear set in a chain about gear  150 , and also concurrently or independently rotation of the mandrels  178  about their respective axes is achieved by operation of the motor  162 . 
     The structure for rotating the pallet  176  and the mandrels  178  when the pallet  176  is in the rotation chamber  18  is the same as in FIG. 4A, but no vertical movement is required so that the motor  148 , the sprockets  136 ,  138 ,  142  and  144  and the chains  134  and  140  are not required. 
     In FIG. 4C, a mandrel holder  200 , all in one piece, that is made of material that does not react with the solvent, has a groove  202  molded and/or machined into it in which an O-ring  204  is seated. In this example, a gear section  208  is coupled via a step-down hub  206  to the groove section  202 . A central shaft  201  is positioned between groove section  202  and a similar groove section  210  on which an X-ring  212  is retained. A hollow glass mandrel  178  fits over and is held by the O-rings  204  and  212 . One end of the mandrel  178  is preferably shaped like a nipple  216 . After the films are formed on the glass mandrel  178  in the processing Section 4 of FIG. 1B, they are coated with silica powder in the powder station  88  of FIG.  1 A. Typically the powder size is about 25 to 40 microns, and is charged at 20,000 to 30,000 volts. The glass mandrel  178  is provided with a conductive coating  218  that is connected via an electrical conductive O-ring  204  to a source of reference potential, such as ground so as to create an electrostatic field that attracts the powder and increases its adherence to the film, in this example. This electrical connection is provided by an electrically conductive brush (not shown) connected between O-ring  204  and shaft  220 . 
     Each mandrel  178  assembly just described is attached to the pallet  176  by a shaft  220  that projects from the center of the gear  208  and through a cylindrical bearing  226 . A washer  224  is mounted on the shaft  220  at the side of the pallet  176  that is opposite to the gear  208  and engages a bearing  226 . A retention nut  228  on the shaft  220  abuts against washer  224 . 
     Rotation of the mandrel  178  assemblies about the axis  220  is achieved by engaging their gears  208  as illustrated in FIG.  4 D and connecting the shaft  166  of the motor  162  to a central one of gears  208  to act as a drive gear. When shaft  166  is engaged in a socket (not shown) of the central gear  208 , and with shaft  166  rotating, each adjacent pair of the gears  208  rotate in opposite directions. 
     The details of the apparatus associated with the takeoff station  90 , and with the X-Y snapper station  92 , will now be described with reference to FIGS. 5 through 27B. In general terms, the takeoff station  90  includes three main subassemblies. With reference to FIG. 5, in a simplified view of the subassemblies located below a plurality of mandrels  178  projecting from a pallet  176  retained by transport unit  85 , the first subassembly includes a top shoe shifting plate  300  positioned over a bottom shoe shifting plate  302 . The top shoe shifting plate  300  includes a plurality of top plate shoes or right-hand shoes  310 , and the bottom shoe shifting plate includes a plurality of bottom plate shoes or left-hand shoes  308  mounted to it, as will be described in greater detail below. Each right-hand shoe  310  is paired with an individual left-hand shoe  308 . Located immediately below the bottom shoe shifting plate  302  is a second subassembly that includes an insert table  304  upon which are mounted a plurality of takeoff inserts  312 . The third subassembly is located below the insert table  304 , and includes an air nipple table  306  upon which are mounted a plurality of air nipple assemblies  314 . Each air nipple assembly  314  includes an air connector assembly  320  secured to the air nipple table  306 , and vertically oriented tubing  318  projecting upward from the air connector assembly  320 . An air nipple  316  is mounted at the top of each of the tubes  318 , as shown. Each of the air nipples  316  are associated with an individual one of the takeoff inserts  312  and individual one of a pair of shoes  308  and  310 . 
     In FIG. 6, a top view looking downward upon the top shoe shifting plate  300 , shows that in this example there are fifteen columns by twenty-seven rows of pairs of top plate or right-hand shoes  310  and bottom plate or left-hand shoes  308 , the pairs totaling  405 . Note that with respect to the right- and left-hand orientation, FIG. 6 is being viewed from the right side of the drawing looking in toward the right side of the top shoe shifting plate  300 . The bottom plate shoes or left-hand shoes  308  of the bottom shoe shifting plate are shown in FIG. 7 looking down upon the top of the bottom shoe shifting plate  302 . The bottom plate shoes  308  project through holes (not shown) in the top shoe shifting plate  300  to be positioned in opposing relationship with their respective top plate shoes  310 , as shown in FIG.  6 . In this regard, as shown in FIG. 8, the top plate or right-hand shoes  310  are positioned as shown on the top shoe shifting plate  300  prior to moving the bottom plate shoes  308  through holes in the top shoe shifting plate  300  (the holes are not shown in this example) for positioning in opposing relationship with respective ones of the top plate or right-hand shoes  310 . 
     A top view of the insert table  304  is shown in FIG.  9 . The takeoff inserts  312  are in this example positioned adjacent to one another and in juxtaposition, in a configuration of fifteen columns by twenty- seven rows, as shown. Each insert  312  includes a hole  313  that is circular in this example, and is concentric with and smaller in diameter than the diameters of both an underlying hole (not shown) through insert table  304 , and a rolled up condom. 
     FIG. 10 shows a top view of the air nipple assembly  314  looking down upon the air nipple table  306 . As shown, the air nipple assembly  314  includes fifteen columns by twenty-seven rows of air nipples  316 , which are juxtaposed to one another. 
     Note that in an engineering prototype machine, the right-hand and left-hand shoes  310 ,  308  were made from Amodel®, the takeoff inserts  312  from Delrin®, and the air nipples  316  from Teflon®. However, any other suitable materials can be used. 
     In FIG. 11 a simplified view is shown of a portion of the mechanism for providing reciprocal motion between the top and bottom shoe shifting plates  300  and  302 , respectively, whereby if one plate is moving in one direction, the other is moving in the opposite direction. In this manner, each of the pairs of shoes  308 ,  310  are selectively moved toward one another, or away from one another, as will be explained in greater detail below. A support post  309  has a gear box assembly  301  bolted to it via a bolts  311 , as shown. Another gear assembly  303  is mounted upon the bottom shoe shifting plate  302  via the button head screws  314 . The gear box  301  is driven by a stepper motor (not shown) for causing a screw  304  to rotate in a clockwise or counterclockwise direction for causing the gear assembly  303  to move back-and-forth on the screw  304 , for in turn causing the bottom shoe shifting plate  302  to move in the direction of the gear assembly  303 . A rack and pinion gearing located between the shifting plates  300  and  302 , causes the top shoe shifting plate  300  to move in a direction opposite to that of the bottom shoe shifting plate  302 . Note that the bottom plate shoes  308  are secured to bottom shoe brackets  327 , which in turn are secured to the bottom shoe shifting plate  302 . Similarly, the top plate shoes  310  are secured via shoe brackets  325  to the top shoe shifting plate  300 . 
     In FIG. 12A, a partial pictorial view looking in at an angle is shown of the top shoe shifting plate  300 , a number of bottom plate and top plate shoes  308 ,  310 , and the gear box  301 , and gear assembly  303 . A portion of the rack and pinion gearing can be seen through an oval hole  309 , in this example, in the top shoe shifting plate  300 . Details of the rack and pinion gear mechanism between the top shoe shifting plate  300  and bottom shoe shifting plate  302  are shown as a side view in FIG. 12B, and as a top view in FIG.  12 C. As shown, the rack and pinion gearing includes a rack gear  333  mounted on the bottom shoe shifting plate  302 , and a pinion gear  337  connected between rack gear  333  and a rack gear  335  mounted on the bottom of the top shoe shifting plate  300 . 
     In FIG. 13, a pictorial view is shown of a corner portion of the mechanism used for raising and lowing the insert table  304  remains level during lifting and lowering. A pinion gear  337  contacts with a rack gear  339  for providing a means to insure the insert table  304  remains level during lifting and lowering. Lifting and lowering power is provided by a pneumatic cylinder  333   a  for providing power to lift and lower the insert table  304 . Note that four air cylinders areh used, with one being located in each corner of the insert table  304  (e.g. see cylinder  333   b  in FIG.  21 ). A plurality of position detecting transducers are used in the system, two of which ( 341  and  343 ) are shown in FIG.  13 . Such detectors may act as a means for limiting the upward or downward movement particular ones of the mechanical assemblies of the takeoff station  90  mechanism, and as housing means. 
     In FIG. 14, an enlarged view of a number of air nipples  316  located beneath a plurality of takeoff inserts  312  is shown. Each of the takeoff inserts  312  includes a circular hole  313  that has a chamfer about the circumference of the underlying holes of insert table  304 . As will be explained below, a condom  307  removed from a mandrel  176 , will during one phase of the takeoff operation be held on top of its associated takeoff insert  312 , as shown on one of the inserts  312  in FIG. 14 in the upper left-hand portion. Note that the overall takeoff geometry described herein can be changed to accommodate different products. 
     FIG. 15 is a pictorial view of a portion of the takeoff apparatus including a gear box  345  that is driven by a servo motor assembly  346  for moving the air nipple table  306  (see FIG.  5 ). Also shown in FIG. 15 are vertical frame members  349 , lateral frame members  351 , an air regulator  354  supplying an air manifold  356  for connection to the air nipple table  306 , and electrical box  347 . Note the relative locations of the insert table  304 , and air nipples  316 , as partially shown in FIG.  15 . 
     As shown in FIG. 16, looking down at a mandrel  178  located between a bottom plate shoe  308  and a top plate shoe  310 , the shoes are resiliently mounted to their respective shoe brackets  327 ,  325 . More specifically, a bottom plate shoe  308  is mounted via two mounting posts  321  to a bottom plate shoe bracket  327 . A helical spring  317  is mounted on a post  321  of shoe  308  between shoe  308  and the inside face of the shoe bracket  327 . The mounting post  321  is secured to the outside face of the shoe bracket  327  via a retainer clip  323 , as shown. Similarly, the opposing top plate shoe  310  is resiliently mounted to its associated top shoe bracket  325 . Note that the bottom shoe brackets  327  are secured to the bottom shoe shifting plate  302  via mounting feet  331  located at the bottom of the brackets  327 , and similarly the top shoe brackets  325  are mounted on the top shoe shifting plate  300  via mounting feet  329  located at the bottom of the shoe brackets  325 . The spring biasing provided by the helical springs  317  is used to substantially reduce the chance of damaging a condom  307  on a glass mandrel  178  due to excess force being applied by the pairs of shoes  308  and  310  when they move toward one another and close upon their associated mandrels  178 , as will be explained in greater detail below. 
     With reference to both FIGS. 16 and 17, note that each one of the shoes  308  and  310  include a projecting flange  308   a , and  310   a , respectively. Also, the cross-sectional view of FIG. 17 shows the shoes  308  and  310  in a closed position upon a mandrel  178  just after partially rolling up the condom  307  to remove it from the mandrel  178 . Note that the closed pair of shoes  308  and  310  provide for engaging a respective condom  307 , whereby as will be explained in greater detail below, when mandrel  178  is moved upward to a position shown in FIG. 17, this movement causes the condom  307  to be rolled downward toward the end of the mandrel  178 . In FIG. 18, a more complete pictorial view is provided for showing substantially the entire mandrel  178  carrying a condom  307  formed thereon, along with two mounting brackets  325  and  327 , and the associated other mechanical features described for FIG. 16 above. In FIG. 19, the pair of shoes  308  and  310  are shown in an open position before being moved into engagement with the condom  307  after mandrel  178  is raised a predetermined amount, as previously described. 
     After the condoms  307  have been removed from their respective mandrels  178 , and powdered at the interior of their closed ends, the condoms  307  are resting on top of the takeoff inserts  312 , respectively, awaiting removal from the takeoff station  90 , as will be explained in greater detail below. The condoms  307  are removed from the takeoff insert  312  via the X-Y snapper station  92  (see FIG.  1 A), a portion of which is shown in FIG.  20 . As shown, a plurality of snapper tubes  356 , three in this example, each have a snapper suction nozzle  358  attached to their open end proximate takeoff station  90  (see FIG.  1 A). A portion of the snapper tubes  356  are mounted upon a trolley  362  for moving the nozzles  358  transverse to the insert table  304 , that is in the X-direction, in this example. A track  364  is provided for the trolley  362 . The nozzles  358  each have a condom entry  360 , as shown, and as further shown in FIG. 21, the X-Y snapper station  92  also includes suction tube CAT racks  366  including links  370  for carrying flexible suction tubes  368 , as shown. The flexible suction tubes  368  are connected to the ends of the suction tubes  356  opposite the suction nozzles  358 , as shown. A motor  372  is located for driving a trolley  374  for moving the suction tubes  356  and associated nozzles  358  into position under the insert table  304  for sucking up condoms  307  from the takeoff inserts  312 . In this regard, note that trolley  374  is driven for moving the suction nozzles  358  in a Y-direction under the insert table  304 , whereas trolley  362  is motor driven (motor not shown) for moving the nozzles  358  in an X-direction, as previously mentioned. Note also a track  364 ′ is located for permitting another X-movement trolley (not shown) to move transversely in the same manner as trolley  362 . 
     An enlarged and detailed view of the assembly of the nozzle  358  is shown in FIG. 22A, and in FIG.  22 B. With reference first to FIG. 22A, the snapper tubes  356  are secured into position at the nozzle end between a top plate  378  and bottom plate  382 , between which spacers  384  are located as shown. The plates  378 ,  382  are secured to the spacers  384  through use of screws  379 , as shown. Bushings  380  are located as shown on the projecting fingers  381  of the top plate  378 . The hard bushings  380  are made higher than the top of the nozzles  358  to adjust the spacing of the nozzles  358  from the bottom surface of the insert table  304 . The bushings  380  are typically made of Nylatron®, or UHMW®, or other suitable plastic material. The bottom front portion  390  of each of the nozzles  358 , include an opening  392  (see FIG.  22 B), in which is mounted a butterfly valve  388  that is rotatable about an axle  387  secured at each end of the collar like member  390  via a retainer cap  386 . The butterfly valve  388  is rotated to close off the opening  392  of its associated nozzle  358  when the nozzle  358  is positioned for sucking a condom from a takeoff insert  312 . At other times, the butterfly valve  388  is positioned to open the port hole  392 . The port  392  is kept open at all times other than when a condom  307  is to be removed from a takeoff insert  312 , to avoid excess vacuum pressure that may pull condoms off of the takeoff inserts  312  at an undesirable angle, causing damage to the condoms  307 . 
     In FIG. 24 a top view is shown of an air nipple  316 , and in FIG. 23 a partial cross-sectional and pictorial view is shown of the air nipple  316  as installed in a air nipple assembly  314 . As shown, an air connector assembly  320  is secured to the top of the air nipple table  306  (see FIG.  5 ). The bottom of the associated tubing  318  is secured to the air connector assembly  320  by air seal collar  404 . Air nipple  316  is held captive on the other end of the tubing  318  via a roll pin  394 , as shown. The air nipple  316  includes a slot way  396  to permit the air nipple  316  to move vertically in a range by sliding on the tube  318 , with the roll pin  394  also providing a stop for limiting downward movement. A spring  398  is positioned as shown between the top of tubing  318  and the top of a hole  399  extending through the air nipple  316  from the bottom to a point just below the nipple-like top portion or tip  397 . A recess  400  is provided in the top of the air nipple  316  for receiving a Gore-tex® insert, in this example, to cushion any contact between the tops of the air nipples  316  and the bottoms of the condoms  307  on glass mandrels  178  during manufacture of the condoms  307 . As further shown in the top view of the air nipple  316  in FIG. 24, four orifices  406  are included about the circumference of the top portion  397 . In this manner, air driven through air inlet  402  and exiting from the orifices holes  406 , causes a condom  307  resting upon the nipple portion  397  to remain inflated during the application of powder to the exposed areas of the condom  307 , and also causes the condom&#39;s tip to be inverted. 
     Greater details of the configuration of the shoes  308  and  310  are provided in FIG. 25A showing a back view of the shoes  308 ,  310 , and a top view thereof as shown in FIG.  25 B. Note that a plurality of mounting posts  321  are vertically orientated, spaced apart, and located in the center in the back of each of the shoes  308 ,  310 , as shown. Note that the mounting posts  321  each include a reduced diameter tip  321   a  for receiving a retainer clip  323 , as previously explained. Greater details of a top shoe mounting bracket  325  are shown in FIG.  26 A. Note that a plurality of holes  325   a  are provided for receiving the tips  321   a  of the mounting post  321 . The mounting flanges  329  are used to secure the shoe bracket  325  to the top of the top shoe shifting plate  300 . As shown in FIG. 26B, the shoe bracket  325  includes a lower extended portion  325   b  from opposing side flanges  325   c . Similarly, as shown in FIG. 27A, and FIG. 27B, the bottom shoe mounting brackets  327  includes a plurality of holes  327   a  for receiving the reduced diameter tips  321   a  of a shoe  308 , and mounting feet or flanges  331 . Also, opposing side flanges  327   c  are provided as shown in FIG.  27 B. Note that the bottom extended portion  327   b  of the bottom shoe bracket  327  is longer than the extended portion  325   b  of the top shoe bracket  325 , for permitting the bottom plate shoes  308  to be properly positioned relatively to the top plate shoes  310 , in this example. Note also that many other configurations can be used for providing the mounting of the shoes  308  and  310 , and the present configuration as shown is not meant to be limiting. Nor are any other features as described above meant to be limiting. 
     With reference particularly to FIGS. 1A,  5 ,  6 ,  9 ,  10 ,  12 A-C,  13 ,  14 ,  17 , and  19  through  24 , the operation for the take off mechanism begins with the dipping transport unit  85  which includes the carrier or pallet  176  for the mandrels  178  positioned with the polyurethane condoms  307  formed on mandrels  178  ready for takeoff over the takeoff station  90 . Note that each of the pairs of shoes  308 ,  310 , are opened by moving the top and bottom shoe plates  300 ,  302 , respectively, in opposite directions to move the individual shoes  308  away from their associated shoes  310 , respectively. To close each pair of shoes  308 ,  310 , the movement of the shoe plates  300 ,  302 , is reversed. The take off operation is initiated by opening the pairs of shoes  308 ,  310  on the take off mechanism, followed by lowering the pallet  176  to lower the mandrels  178 . Once the respective pairs of shoes are opened, the mandrels  178  are lowered for the first stroke and the ring  319  of each condom is positioned near the bottom of the associated shoes  308 ,  310 . The respective shoes  308 ,  310  are then closed to a predetermined position, and then the pallet  176  is moved upward rolling the condoms  307  approximately one-third down their associated glass mandrels  178  (see FIGS. 17 and 18) via the frictional contact between shoes  308  and  310  and the rings  319  of the condoms  307  (see FIG.  19 ). The shoes  308 ,  310  are opened again, and the condoms  307  and associated mandrels  178  are repositioned with the rings  319  at the bottom of their associated shoes  308 ,  310 . The individual pairs of shoes  308 ,  310  are then closed to a predetermined position against the ring  319  of their associated condom  307 , and again the associated mandrels  178  are withdrawn or moved upward for rolling the associated condoms  307  approximately three-quarters or more down their respective mandrel  178 . In the final and third stroke, the pairs of shoes  308 ,  310  are opened again, the associated mandrels  178  are reinserted their required depth into their associated pairs of shoes  308 ,  310 , respectively, and the shoes  308 ,  310  are closed. At this time, the air nipple table  306  holding the four-hundred-and-five air nipples  316 , in this example, is raised with air blowing out of orifices  406  of nipples  316 , respectively, and then transfers upward at the same rate of upward movement of the glass associated mandrels  178 , respectively, maintaining about a sixteenth to a thirty-second inch space between the tip  397  of each air nipple  316 , and the tip of the associated glass mandrel  178 , while the associated condom  307  is being rolled up by its shoes  308 ,  310 . At the final withdrawal, the tips  397  of each air nipple  316  are at a position above the shoes  308 ,  310  with the associated condoms  307  deposited on them in an inside out or upside down orientation mode, respectively. Next, the pairs of shoes  308  and  310  are opened. The air nipple table  306  is then lowered, causing the rolled up condoms  307  on respective air nipples  316  to move down through associated shoes,  308 ,  310 . The condoms  307  are deposited on respective takeoff inserts  312  since the diameter of the condoms  307  is larger than the diameter of holes in the inserts  312 . The associated air nipples  316  continue to move downward to a position below the insert table  304 . Next, a set of tubes (not shown) underneath the bottom shoe shifting plate  302  sprays powder on the tips or nipples of the condoms  307 , because at that time the tip is the only portion of each condom  307  that is unrolled and unpowdered. The powdering prevents condoms  307  from sticking together, and occurs just before the insert table  307  is raised up. After powdering, the insert table  304  is raised to an uppermost position, the X-Y snapper nozzles  358  are then swept underneath the insert table  304 , for withdrawing or sucking the condoms  307  through the takeoff inserts  312  down through the snapper tubes  356 , which at least partially unrolls the condoms  307 . Note that both the chamfer and diameter of the hole through each of the takeoff inserts  312  are configured to maximize the extent of partially unrolling condoms  307  passing through, while preventing damage thereto. The takeoff inserts  312  can consist of any suitable material, such as a plastic material (Teflon®, nylon, and so forth). 
     The air nipple table  306  carrying the air nipple assemblies  314  (see FIG.  5 ), is raised and lowered by a servo motor (not shown) located to the side of the table  306  that is driving chain driven gears (not shown), along with an air assist lift mechanism (not shown) in order to take the load off the servo motor. The table  306  carrying the takeoff inserts  312  is driven upward and downward through use of a rack pinion mechanism  337 ,  339  connected to an air assist cylinder  333   a  (four cylinders are used, via at each corner, such as cylinder  333   b  in FIG. 21, but the two other air cylinders are not shown). The pairs of takeoff shoes  308 ,  310  are in opposing relationship, and are alternately connected to upper and lower or top and bottom shoe shifting plates  300 ,  302 , respectively, as previously mentioned. The plates  300 ,  302  are driven in reciprocal motion through use of a rack pinion drive mechanism  333 ,  335 ,  337  that is driven by a single stepper motor (not shown). The stepper motor drives two- Gear Boxes (not shown) to drive rack pinion mechanisms (not shown) at either side of the plates  300 ,  302  upon which the shoes  308 ,  310  are mounted. Rotating rods (not shown) drive gears (not shown) that in turn drive a pinion gear  337  either clockwise or counterclockwise for causing the lower shoe plate  302  to move horizontally in one direction and the upper shoe plate  300  to move horizontally in the opposite direction, for simultaneously opening and closing all of the pairs of shoes  308 ,  310  of the takeoff station  90 , in order to roll-up a condom  307  on each of the respective mandrels  178 . The number of times that the shoes  308 ,  310  are so closed and opened, along with upward and lower movement of each one of the mandrels  178  is in this example as previously described in the above paragraphs. However, in other embodiments, the number of times of opening and closing shoes  308  and  310  can be more or less than three. The opposing shoes  308 ,  310  are retained on lower and upper plates  300 ,  302 , respectively, via spring biasing attachment means, for permitting the shoes to resiliently contact the condoms during a takeoff cycle, as described in detail above. 
     A redress and inspection station  99  is located at the end of the drying section after the staging conveyor station  97 , and permits the pallets  176  to be selectively brought out after washing and rinsing for access by the operators in order to either replace or tighten mandrels  178 , strip-off any condom  307  that may have not been removed during prior processing, or otherwise make whatever repairs or adjustments that are necessary as previously mentioned. The nipple support Teflon® air nipples  316  each have a Gore-tex® tip in order to prevent cutting of a condom  307  if the tip of an associated condom  307  happens to come in contact with the bottom of one of the mandrel tubes  178 . Also, the air nipple table  306  retains the air nipple assemblies  314 . The air nipples  316  each have nipple holders formed at their tips  397  (see FIG.  23 ), and each have a manifold built into their bottom portions for permitting air to flow up through the center of the main support tubes  318 , through the associated air nipples or tip  316 , and out of small holes or orifices  406  in the center portion of the tip  397  of the air nipples  316 , respectively, in order to expand the nipple portions of the condoms  307  for proper powdering. On the third stroke or step of the condom removal operation, the air nipples  316  move upward to lift up the condoms  307 , then the shoes  308 ,  310  opened, and the air nipples  316  drop backdown, whereby the condoms  307  are deposited on the takeoff inserts  312  of the insert table  304 , the insert table  304  moves down, followed by spray bars (not shown) being operated for spraying powder onto the nipple ends of the condoms  307 , as previously described. Then the insert table  304  is raised, whereafter the X-Y snapper system  92  is operated in order to sweep the snapper suction heads  358  under the insert table  304  for sucking the condoms into the takeoff tubes  356 , and then into a central tube (not shown) for deposit into a receptacle on the outside of the machine, as described in detail above. 
     Note that the datums or home positions are all established relative to a stepper motor (not shown) associated with the X-Y snapper system  92 , and the stepper motor (not shown) associated with the shoe shifting plates  300 ,  302 . A proximity detector or transducer is used in order to provide a datum signal for signaling the system that the shoe plates  308 ,  310  are at a home position. Note also that proximity sensors (not shown) are used for detecting whether the insert table  304 , and the air nipple table  306  are in upper or lower positions, respectively. Note further that the air nipple table  304  uses a servomotor (not shown), whereas the X-Y snapper system  92  and the shoe plates  300 ,  302  use stepper motors, in this example. The stepper motors and servo motors can all be programmed very precisely to 0.002 inch for positioning the glass mandrels  178  relative to the shoes  308 ,  310 , relative to the insert table  312 , and relative to the air nipple table  306 . 
     The present invention has been used in experimental or test runs to produce polyurethane condoms  307  having thicknesses ranging from 0.035 mm to 0.060 mm, and lengths from 175 mm to 190 mm. The condoms  307  had a tapered configuration. 
     In another embodiment of the invention, as shown in FIG. 28A, the previously mentioned reservoir dipping tank  36  of polyurethane material dissolved in THF (see FIG. 1B) includes a sliding top cover plate  402  that includes holes  406 , as shown. The top  400  of tank  36  includes holes  404 . A drive arm  408  of an air cylinder  410  is attached to one end of the sliding plate  402  for selectively moving the sliding plate  402  between a first or open position (see FIG. 28A) for exposing holes  404  through associated holes  406 , and a closed position (see FIG. 28B) for substantially closing off the holes  404  in the top  400  of the tank  36 . In the open or dipping position of the sliding plate  402 , the holes  406  are in a position where they are concentric with associated underlying holes  404  through the otherwise closed off top  400  of the dipping tank  36 . In this open position, the holes  406  of the sliding plate  402 , and the underlying associated holes  404  in the top  400  of the tank  36  are respectively each configured to have the minimum diameter required for permitting an associated mandrel  178  to be passed through the holes into the dipping solution in the tank  36 . By maintaining the minimum diameter necessary for the plurality of overlying holes  406  and  404 , respectively, the THP concentration about the associated mandrels  178  is kept substantially rich or high as the mandrels  178  are withdrawn from the tank  36  to prevent premature rapid evaporation of the THF solvent, for in turn permitting control of the withdrawal rate. Also, by maintaining a high concentration of THF vapors about the mandrels  178  as they are dipped into the dipping solution contained in tank  36 , the entry rate of dipping can be more finely controlled to minimize film defects. 
     Although various embodiments of the invention are shown and described herein, they are not meant to be limiting. Various modifications may occur to those of skill in the art, which modifications are meant to be covered by the spirit and scope of the appended claims. For example, with certain modification, the present system of the invention can be used to produce other than condom products, such as catheters and other medical devices, finger cots, gloves, coating processors, and so forth. Also, in an alternative embodiment, the takeoff inserts  312  can be eliminated by making the underlying holes in insert table  304  (see FIG. 9) to each have a chamfer and a diameter less than that of a rolled up condom  307 . However, the preferred embodiment of the invention includes the takeoff inserts  312 .

Technology Classification (CPC): 1