Abstract:
The present disclosure relates to an epoxy applicator including an epoxy dispenser and a thermal pump. The epoxy dispenser includes an epoxy holding cavity that is cooled by the thermal pump via a thermal conduction member. A control system can regulate a temperature of the epoxy applicator and thereby regulate a temperature of uncured epoxy in the epoxy holding cavity. The present disclosure also relates to a syringe chiller for chilling a syringe. The syringe chiller includes a thermal conduction block adapted to thermally couple to and hold an exterior of the syringe. The syringe chiller also includes a Peltier effect device with a hot side and a cold side. The cold side of the Peltier effect device is thermally coupled to the thermal conduction block. The syringe chiller can include a control system to regulate a temperature of the syringe.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/226,454, filed Jul. 17, 2009, which application is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to epoxy applicators and, more particularly, to epoxy applicators suitable for use in preparing fiber optic connectors. 
       BACKGROUND 
       [0003]    Epoxy adhesives have been used in bonding and securing electrical and optic components. Epoxies are typically a thermosetting polymer that cures when mixed with a catalyzing agent or hardener. Epoxies typically have a consistency ranging from liquid to putty prior to being cured. After curing, epoxies typically set up as a solid resistant to deformation. Cured epoxy properties such as heat and chemical resistance are suitable for many applications including consumer, marine, tooling, dentistry, aerospace, optic, and fiber optic applications. 
       SUMMARY 
       [0004]    Features of the present disclosure relate to an epoxy applicator. The epoxy applicator includes an epoxy dispenser (e.g., a syringe), a thermal conduction member (e.g., an aluminum block), and a thermal pump. The epoxy dispenser includes an epoxy holding cavity and an epoxy nozzle. The epoxy nozzle includes an epoxy flow passage that connects the epoxy holding cavity to an outlet of the epoxy nozzle. The thermal conduction member is thermally coupled to a wall of the epoxy holding cavity. The thermal pump includes a thermal energy source surface (i.e., a cold side) and a thermal energy sink surface (i.e., a hot side). The thermal energy source surface is thermally coupled to the thermal conduction member. The thermal energy sink surface is adapted to dissipate thermal energy into a surrounding environment. The thermal pump has an active state and an inactive state. When the thermal pump is in the active state, the thermal pump transfers the thermal energy from the thermal energy source surface to the thermal energy sink surface and thereby lowers a temperature of the thermal energy source surface. The lowered temperature of the thermal energy source surface of the thermal pump, in turn, lowers a temperature of the thermal conduction member, and the lowered temperature of the thermal conduction member, in turn, lowers a temperature of the wall of the epoxy holding cavity of the epoxy dispenser. 
         [0005]    The epoxy applicator can also include one or more temperature sensors adapted for measuring the temperatures of the thermal energy source surface, the thermal conduction member, and/or the wall of the epoxy holding cavity. The epoxy applicator can also include a control unit that drives one or more of the temperatures or an average of the temperatures measured by the temperature sensors toward a temperature set point. 
         [0006]    The thermal pump of the epoxy applicator can be or include a Peltier effect device, a vapor-compression refrigeration device, or other device capable of transferring the thermal energy (i.e., heat) away from the epoxy holding cavity. 
         [0007]    The epoxy applicator can be adapted for injecting uncured epoxy, loaded in the epoxy holding cavity, into a hub and/or a ferrule of a fiber optic connector. For example, the epoxy nozzle of the epoxy applicator can be a hollow needle and the outlet can be positioned at a tip of the hollow needle. The hollow needle can include a tapered seat positioned around the outlet at the tip of the hollow needle. The tapered seat of the hollow needle can be adapted to seat against a chamfer of a ferrule of a fiber optic connector. 
         [0008]    The epoxy applicator can include a fan, adapted to move air across the thermal energy sink surface of the thermal pump, and insulation around at least a portion of an exterior of the thermal conduction member. Insulation can also be applied on and around at least portions of the epoxy dispenser. 
         [0009]    The epoxy dispenser can be removably mounted to other members of the epoxy applicator. For example, the thermal conduction member can include a through-hole adapted to hold and thermally couple with the epoxy dispenser. The epoxy dispenser can be inserted and removed from the through-hole. 
         [0010]    Features of the present disclosure also relate to a syringe chiller for chilling a syringe. The syringe chiller includes a thermal conduction block and a Peltier effect device. The thermal conduction block includes an exterior surface and a through-hole adapted to thermally couple to and hold an exterior of the syringe. The Peltier effect device includes a hot side and a cold side. The cold side is thermally coupled to the exterior surface of the thermal conduction block, and the hot side is adapted to dissipate thermal energy into a surrounding environment. The Peltier effect device includes electrical power leads. A temperature of the hot side increases and a temperature of the cold side decreases when a voltage is applied across the electrical power leads. Applying the voltage thereby transfers the thermal energy from the cold side to the hot side of the Peltier effect device. The cold side of the Peltier effect device cools the exterior surface of the thermal conduction block and thereby cools the through-hole of the thermal conduction block when the voltage is applied across the electrical power leads of the Peltier effect device. 
         [0011]    The syringe chiller can include a control system and one or more temperature sensors. The temperature sensors can measure either or both the temperature of the cold side of the Peltier effect device and/or a temperature of the thermal conduction block. The control system can drive the temperatures measured by the temperature sensors or their average toward a desired temperature by regulating the voltage applied across the electrical power leads of the Peltier effect device. 
         [0012]    The syringe chiller can include a fan adapted to move air across the hot side of the Peltier effect device. The syringe chiller can include insulation around at least a portion of an exterior of the thermal conduction block. 
         [0013]    These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the forgoing general description and the following detailed description are explanatory only and are not restrictive of the broad aspects of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view showing an epoxy applicator in accordance with the principles of the present disclosure; 
           [0015]      FIG. 2  is another perspective view showing the epoxy applicator of  FIG. 1 ; 
           [0016]      FIG. 3  is still another perspective view showing the epoxy applicator of  FIG. 1  with a tip of the epoxy applicator near a ferrule assembly of a fiber optic connector; 
           [0017]      FIG. 4  is an enlarged partial view of  FIG. 3  showing the tip of  FIG. 3  in greater detail; 
           [0018]      FIG. 5  is the perspective view of  FIG. 3  but with the tip and the ferrule assembly of  FIG. 3  engaged with each other; 
           [0019]      FIG. 6  is the perspective view of  FIG. 5  but with a cross-sectional cut through the epoxy applicator and the ferrule assembly revealing their inner details; 
           [0020]      FIG. 7  is an enlarged partial view of  FIG. 6  showing the cross-sectioned tip and the cross-sectioned ferrule assembly of  FIG. 3  in greater detail; 
           [0021]      FIG. 8  is an exploded perspective view of the epoxy applicator of  FIG. 1 ; 
           [0022]      FIG. 9  is another exploded perspective view of the epoxy applicator of  FIG. 1 ; 
           [0023]      FIG. 10  is a schematic illustration of the epoxy applicator of  FIG. 1  connected to a control system; 
           [0024]      FIG. 11  is a perspective view showing a fiber optic cable terminated by a fiber optic connector; and 
           [0025]      FIG. 12  is the perspective view of  FIG. 11  but with a cross-sectional cut through the fiber optic cable and the fiber optic connector revealing their inner details and with a cap and a cap strap removed. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The present disclosure describes example methods of chilling epoxy adhesive in an epoxy applicator. In addition, the present disclosure describes regulating a temperature of the epoxy applicator and a temperature of the epoxy adhesive within the epoxy applicator. 
         [0027]    Epoxies are typically stored as two components for an extended period of time in a liquid, a gel, or a putty form. Before use, the two components of a typical epoxy are mixed together starting a curing process. A limited amount of time is available to apply the mixed epoxy before it cures to a solid form. The limited amount of time before curing depends, in part, on a temperature of the mixed epoxy. A cooler temperature of the mixed epoxy typically extends the curing time while a warmer temperature typically shortens the curing time. 
         [0028]    The mixed epoxy can be loaded into an epoxy applicator to aid in the application of the mixed epoxy (e.g., in placing the mixed epoxy between two or more components to be bonded together). The two components of the epoxy can also be mixed by an epoxy applicator while the epoxy is being applied. By cooling the temperature of either the mixed epoxy or the two components of the epoxy before mixing, the curing time of the epoxy can be extended. By controlling the temperature of either the mixed epoxy or the two components of the epoxy before mixing, consistency of the curing time and consistency of the cured epoxy can be increased. 
         [0029]    In applications, such as an assembly line, where doses of the mixed epoxy are applied to multiple units, extending the curing time of the mixed epoxy, loaded into the epoxy applicator, can increase the number of units that are processed before the mixed epoxy cures inside the epoxy applicator and becomes unusable. Therefore, extending the curing time of the mixed epoxy inside the epoxy applicator can spread the cost of the mixed epoxy over a greater number of units and reduce waste. 
         [0030]      FIGS. 1 and 2  show an example epoxy applicator  20  in accordance with the principles of the present disclosure. The epoxy applicator  20  includes a thermal unit  22  and an epoxy dispenser  24 . 
         [0031]    The epoxy dispenser  24  can include a syringe  49  including a syringe body  50  and a plunger  52 , as illustrated, or can be other means for storing and dispensing epoxy  10  (see  FIG. 6 ). The syringe  49  can be disposable after use or reusable. The syringe  49  can include a single chamber in the syringe body  50  and a single piston on the plunger  52 , as illustrated, or can include double chambers or multiple chambers in a syringe body and double pistons or multiple pistons on a plunger. 
         [0032]    The syringe  49  is illustrated in cross-section at  FIG. 6  and exploded at  FIGS. 8 and 9 . The syringe  49  includes a thermal contact surface  51  (shown on an exterior of the syringe body  50  at  FIG. 9 ). The syringe body  50  extends from a first end  60  to a second end  62  and includes a bore  58  open to the first end  60 . The first end  60  of the syringe body  50  can include a flange  61 , and the second end  62  of the syringe body  50  can include a necked down region, open to the bore  58 , surrounding an outlet of the syringe body  50 . The plunger  52  of the syringe  49  extends from a first end  66  to a second end  68  and includes a sealing piston  64  at the second end  68 . The first end  66  of the plunger  52  can include an actuation surface  53 . A hollow needle  54  can be mounted in the outlet of the syringe body  50 . The hollow needle  54  extends from a first end  70  to a second end  72  (i.e., a tip) and includes a passage  74  extending from the first end  70  to the second end  72 . The first end  70  of the hollow needle  54  can be held within the second end  62  of the syringe body  50 . The passage  74  of the hollow needle  54  is open to the bore  58  of the syringe body  50 . The second end  72  (i.e., the tip) of the hollow needle  54  can include a tapered seat  76  surrounding the passage  74  at the second end  72 . 
         [0033]    When the second end  68  of the plunger  52  is inserted into the bore  58  of the syringe body  50  through the first end  60  (see  FIG. 9 ), a cavity  56  is formed within the syringe  49  between the sealing piston  64  and an end wall at the second end  62  of the syringe body  50 . The cavity  56  is further bounded by the bore  58  surrounded by a circumferential wall of the syringe body  50 . The epoxy  10  can be loaded into the bore  58  through the first end  60  prior to inserting the plunger  52  into the bore  58 , or the epoxy  10  can be drawn into the cavity  56 . To draw the epoxy  10  into the cavity  56 , the second end  68  of the plunger  52  can be fully inserted into the bore  58 . The epoxy  10  can then be drawn into the cavity  56  by pulling the plunger  52  away from the second end  62  of the syringe body  50 . To expel the epoxy  10  from the cavity  56 , an operator&#39;s first and second fingers can be hooked under the flange  61  of the syringe body  50  while the operator&#39;s thumb presses against the actuation surface  53  of the plunger  52 . This action creates pressure within the cavity  56  and urges the epoxy  10  out through the outlet of the syringe body  50 . If the hollow needle  54  is attached to the syringe body  50 , as described above and illustrated at  FIG. 6 , the epoxy  10  will be urged through the passage  74  of the hollow needle  54  and out of the second end  72  of the hollow needle  54 . 
         [0034]    The thermal unit  22  of the epoxy applicator  20  can include a Peltier device  40  as illustrated at  FIGS. 2 ,  8 , and  9 . The thermal unit  22  can include a vapor-compression refrigeration device or other device capable of transferring thermal energy (i.e., a thermal pump). The Peltier device  40  creates a temperature gradient from an applied electrical voltage by employing the thermoelectric effect (i.e., the Seebeck effect, the Thomson effect, the Peltier-Seebeck effect, etc.). When the electrical voltage is applied across a first lead  46  and a second lead  48  of the Peltier device  40 , a thermal energy source surface  42  (i.e., a cold side) and a thermal energy sink surface  44  (i.e., a hot side) is formed on the Peltier device  40 . Thermal energy (i.e. heat) is drawn from the cold side  42  and transferred to the hot side  44  thereby cooling the cold side  42  and heating the hot side  44 . In the figures, the cold side  42  and the hot side  44  of the Peltier device  40  are shown as planar and on opposing sides. Alternatively, the cold side  42  and the hot side  44  could be cylindrical. For example, the Peltier device  40  can take a form of a tube, and the cold side  42  can be a portion or all of an inside surface of the tube, and the hot side  44  can be a portion or all of an outside surface of the tube. 
         [0035]    To cool the syringe  49 , the cold side  42  of the Peltier device  40  is thermally connected to the thermal contact surface  51  of the syringe  49 . As illustrated at  FIGS. 2 ,  6 ,  8 , and  9 , a thermal conduction member  30  includes a syringe contacting surface  32  and a Peltier contacting surface  34 . The thermal conduction member  30  is preferably made from a material with good thermal conduction properties (e.g., aluminum, copper, or silver). The syringe contacting surface  32  of the thermal conduction member  30  is brought into thermal contact with the thermal contact surface  51  of the syringe, and the Peltier contacting surface  34  of the thermal conduction member  30  is brought into thermal contact with the cold side  42  of the Peltier device  40 . The syringe  49  is thereby thermally connected with the cold side  42  of the Peltier device  40 . In the illustrated embodiment, the thermal conduction member  30  is a separate piece from the Peltier device  40 . In other embodiments, the thermal conduction member  30  can be integrated with the Peltier device  40 . 
         [0036]    The thermal conduction member  30  can further include a temperature sensor mount  38  and a temperature sensor lead channel  39 . 
         [0037]    The syringe contacting surface  32  of the thermal conduction member  30  can take the form of a through-hole. The syringe  49  can be easily installed and removed from the through-hole. Having the syringe  49  easily removable from the thermal conduction member  30  also allows the syringe  49  to be easily removable from the other components of the epoxy applicator  20  (e.g., the thermal unit  22 ). Having the syringe  49  be easily removable provides the benefit of conveniently filling the syringe  49  with the epoxy  10  in the absence of the rest of the epoxy applicator  20 . Having the syringe  49  be easily removable also provides the benefit of being able to quickly and conveniently switch the syringes  49  (e.g., when using multiple syringes  49  and/or when using disposable syringes  49 ). 
         [0038]    Insulation  80  can be applied to other surfaces  36  of the thermal conduction member  30  that do not have a primary function as a thermal contact. The insulation  80  improves the efficiency of the thermal unit  22  by limiting unwanted environmental thermal transfer. The insulation  80  includes an insulated side  86  and an environment side  88 . The insulated side  86  is primarily in contact with the other surfaces  36  of the thermal conduction member  30 , and the environment side  88  is primarily exposed to a surrounding environment (e.g., ambient air). The insulation  80  can include a first hole  82  and a second hole  84  that generally align with the through-hole of the syringe contacting surface  32  of the thermal conduction member  30 . The insulation  80  can include a lead access  89 . Insulation can also be applied to other components of the epoxy applicator  20 . For example, all or a portion of the hollow needle  54 , the syringe body  50 , and/or the plunger  52  can be thermally insulated. 
         [0039]    As illustrated at  FIGS. 2 ,  8 , and  9 , the epoxy applicator  20  can include a fan  90 . The fan  90  moves air across the hot side  44  of the Peltier device  40 . By moving the air across the hot side  44 , thermal energy (i.e., heat) can be removed from the hot side  44 . As illustrated at  FIG. 10 , the fan  90  includes a first electrical power connection  91  and a second electrical power connection  93  to supply electrical power to an electric motor. When electrical power is supplied to the electric motor of the fan  90 , the electric motor turns a fan blade of the fan  90 , thereby moving the air into a first opening  92  and out of a second opening  94  of the fan  90 . The rotational direction of the electric motor can be reversed thereby moving the air into the second opening  94  and out of the first opening  92  of the fan  90 . The fan  90  can include a first set of mounts  96  and a second set of mounts  97 . As illustrated at  FIG. 2 , the first set of mounts  96  can attach to the Peltier device  40 . A gap  98  can be formed between the fan  90  and the hot side  44  of the Peltier device  40  by the first set of mounts  96 . The gap  98  can allow air to pass through. 
         [0040]    As illustrated at  FIG. 10 , the epoxy applicator  20  can include a controller  100  (i.e., a control system). The controller  100  can measure and regulate the temperature of the epoxy applicator  20  and therefore regulate the temperature of the epoxy  10  within the cavity  56 . The controller  100  can further regulate a speed of the fan  90  and a rate of cooling. A temperature set point (i.e., a desired temperature) can be set on the controller  100  by an operator. The controller  100  can include a temperature indicator display, an on/off switch, fault indicators, etc. The controller  100  can include a power supply for the fan  90  and a power supply for the Peltier device  40 . The controller can read a signal from a temperature sensor  110 . 
         [0041]    In the example illustrated at  FIG. 10 , a first Peltier power lead  102  of the controller  100  is connected to the second lead  48  of the Peltier  40 , a second Peltier power lead  103  of the controller  100  is connected to the first lead  46  of the Peltier  40 , a first fan power lead  105  of the controller  100  is connected to the first power connection  91  of the fan  90 , a second fan power lead  106  of the controller  100  is connected to the second power connection  93  of the fan  90 , a first temperature sensor signal lead  108  of the controller  100  is connected to a first lead  112  of the temperature sensor  110 , and a second temperature sensor signal lead  109  of the controller  100  is connected to a second lead  114  of the temperature sensor  110 . 
         [0042]    The temperature sensor  110  can be mounted on or in the temperature sensor mount  38 , as illustrated at  FIGS. 8 and 9 . The first and the second temperature sensor leads  112 ,  114  can be routed along the temperature sensor lead channel  39  and through the lead access  89  of the insulation  80 . 
         [0043]    The above components of the epoxy applicator  20  can be used to apply the epoxy  10  in various applications. A particular example application of applying the epoxy  10  to a fiber optic connector  201  and to a connector terminated fiber optic cable assembly  200  will be briefly described below. For further details on the fiber optic connector  201  and the connector terminated fiber optic cable assembly  200 , see U.S. Provisional Patent Application Ser. No. 61/007,222, filed Dec. 11, 2007; U.S. Provisional Patent Application Ser. No. 61/029,524, filed Feb. 18, 2008; and the following U.S. Patent Applications, all filed on Sep. 3, 2008: U.S. patent application Ser. No. 12/203,508, entitled “Hardened Fiber Optic Connector Compatible with Hardened and Non-Hardened Fiber Optic Adapters”; U.S. patent application Ser. No. 12/203,522, entitled “Hardened Fiber Optic Connection System”; U.S. patent application Ser. No. 12/203,530, entitled “Hardened Fiber Optic Connection System with Multiple Configurations”; and U.S. patent application Ser. No. 12/203,535, entitled “Hardened Fiber Optic Connector and Cable Assembly with Multiple Configurations”; which applications are hereby incorporated by reference in their entirety. 
         [0044]    The above components of the epoxy applicator  20  can also serve purposes other than applying epoxy. For example, the above components can serve as a syringe chiller. The syringe chiller can be used for a variety of purposes that syringes are used for. 
         [0045]      FIGS. 11 and 12  illustrated the fiber optic connector  201  and the connector terminated fiber optic cable assembly  200 . The fiber optic connector  201  extends from a first end  202  to a second end  204 . The first end  202  attaches to an end of a fiber optic cable  218  including an optical fiber  220 . The second end  204  includes a ferrule assembly  210 . The ferrule assembly  210  includes a ferrule  212  and a hub  214 . A fiber bore  230  runs through the ferrule  212  and mounts (i.e., terminates) an end of the optical fiber  220 . The hub  214  includes a fiber clearance bore  216  and a ferrule bore  215  (see  FIG. 7 ). A first end  232  of the ferrule  212  is coincident with the end of the optical fiber  220 . A second end  234  of the ferrule  212  is inserted into the ferrule bore  215  of the hub  214 , and an outer surface  238  of the ferrule  212  is held in the ferrule bore  215 . The ferrule  212  and the hub  214  can be pre-assembled. 
         [0046]      FIGS. 3-7  illustrate injecting the epoxy  10  into the fiber bore  230  of the ferrule  212 . As illustrated, the ferrule assembly  210  is separated from the rest of the fiber optic connector  201 . In other embodiments, the epoxy  10  can be injected into the fiber bore  230  while the ferrule assembly  210  is installed in the fiber optic connector  201  (a longer version of the hollow needle  54  can be used in this embodiment). The ferrule assembly  210  is positioned near the second end  72  of the hollow needle  54  as illustrated at  FIG. 3 . The ferrule assembly  210  is then moved in an insertion direction  250  causing the hollow needle  54  to pass through the fiber clearance bore  216  of the hub  214 . The ferrule  212  is brought to rest against the second end  72  of the hollow needle  54  as shown at  FIGS. 5-7 . A taper seat  236  at the second end  235  of the ferrule  212  can be brought into contact with the tapered seat  76  of the hollow needle. A dose of the epoxy  10  is then injected into the fiber bore  230  of the ferrule  212 . The ferrule assembly  210  can then be removed and installed in the fiber optic connector  201 . The optical fiber  220  is inserted into the fiber bore  230  of the ferrule  212 . 
         [0047]    The epoxy adhesive  10  can be applied by the epoxy applicator  20  to other components of the fiber optic connector  201  and the fiber optic cable  218 . 
         [0048]    When the voltage polarity to the Peltier device  40  is reversed, the cold and the hot sides  42 ,  44  are switched. This effect can be used to warm the epoxy applicator  20  and warm the epoxy applicator  20  to a specified temperature. This effect can also be used to control the temperature of the epoxy applicator  20  by alternately adding and removing thermal energy as needed regardless if the ambient temperature is warmer or colder than the desired temperature. 
         [0049]    Reversing the voltage polarity to the Peltier device  40 , as described in the preceding paragraph, can also be applied to the syringe cooler, thereby transforming it into a syringe warmer. Likewise, the syringe cooler can be transformed into a syringe temperature maintaining device. 
         [0050]    From the forgoing detailed description, it will be evident that modifications and variations can be made without departing from the spirit and scope of the disclosure.