Abstract:
An APS single use camera has a cover with an aperture that provides access to the film sensor and the light lock door driver via a tool adapted to be received into the aperture. The tool is used to open the light lock door and push the film sensor out of the film path so as to enable film from the APS film cassette to be scrolled into the film path. The structure permits pre-loading of film outside of a darkroom, and such a method is disclosed. The camera also employs a brake that prevents the film sensor from sensing for the presence or absence of film except during a brief sensing interval that occurs during a film advance operation.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is related to and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/126,880, filed Mar. 30, 1999, entitled “APS Camera and Method.” 
    
    
     BACKGROUND OF THE INVENTION 
     Conventional film cartridges, such as 35 mm film cartridges, have a film leader extending therefrom at the time of purchase, and a brush or similar mechanism at the cartridge&#39;s film slot to prevent light from entering the cartridge and exposing film contained therein. Another type of film cassette is variously referred to as an “APS film cassette” (wherein APS means Advanced Photo System), a “film safe cassette”, or a “SSU film strip loaded cartridge.” One example of such a film cassette is KODAK® brand ADVANTIX® film. The cameras with which these film cassettes are used are known as APS cameras. APS film cassettes do not, at the time of purchase, or at the time the film is first inserted into the camera, have a film leader extending from the cassette to facilitate film loading. Instead, APS film cassettes have a light lock door that must be opened in order to advance or scroll the film from the cassette. Once the light lock door of the film cassette has been opened, ambient light is free to enter the cassette and expose the film within the cassette. Therefore, the light lock door of an APS film cassette must be opened either inside of a light sealed camera or in darkroom conditions to prevent the film therein from being inadvertently exposed. 
     In conventional cameras, such as conventional 35 mm cameras, film is usually loaded from the back of the camera by opening a back door thereof, placing the cartridge into the camera, pulling the film leader across the camera, engaging the leader on a take-up spool and then closing the back door. Since opening the light lock door of an APS film cassette in the presence of light can expose the film within the cassette, conventional methods of loading film are not suited to APS cameras. 
     A typical APS film loading sequence involves loading film into the camera through a film cassette door disposed on the bottom of the camera and then closing the film cassette door to light-tightedly seal the camera. Following this, the light lock door of the film cassette is opened. The film is then driven out of the cassette, across a film path, and into a film spooling area on the opposite side of the camera from the cassette. Before the cassette can be removed from the camera, the film must be rewound back into the cassette, and the light lock door must be closed. Thus, APS cameras are designed to prevent opening of the film cassette door when the light lock door is open. 
     So called single use cameras are known in the art. A single use camera is one that has been preloaded with film at the factory and sold to the consumer with the intent of being used only a single time (i.e., with only the roll of preloaded film) by the end user. (Preloading generally connotes the process of loading the camera with a spool of unexposed film in a film spool compartment that is opposite the film cartridge/cassette compartment such that, as exposures are taken, the exposed film is wound back into the film cartridge or cassette. Prewinding connotes the process of winding or spooling the unexposed film into the film spool compartment.) For 35 mm single use cameras, this is usually done by loading the film into the back camera in much the same way that a conventional 35 mm camera is loaded, then securely assembling a back cover to the camera by a locking mechanism, screws, adhesives, thermal bonding, etc. The film can be prewound into the film spool compartment of the camera either before the back cover is affixed to the camera (by spooling the film externally of the camera then placing the spool film in the film spool compartment) or after the back cover has been affixed to the camera (by applying a winding tool to the film spool). Typically, a package (such as paper, cardboard, plastic and/or adhesive labels) is placed on or around the camera body. (Hereinafter, the term “package” as used in connection with this application is intended to refer to both cardboard, paper, plastic and other types of packaging that may at least partly surround the camera body, and adhesive labels that may be affixed to at least front and/or back covers of the camera.) Depending upon the nature of the package, the film may not be removed without destroying at least part of the package. Usually, the film cannot be removed without destroying or disassembling part of the camera body. Additionally, film cannot easily be reloaded into the camera by the end user, at least not without partial destruction or disassembly of the camera body and/or its packaging. As described in commonly assigned U.S. Pat. Nos. 5,689,733 and 5,832,311 (hereinafter “the 733 and 311 patents”), the entirety of each of which is incorporated herein by reference, single use 35 mm cameras are usually loaded with the back cover removed so that the film leader can be attached to a film spool and/or so that the film can be wound into the film spool compartment. 
     Single use APS cameras are also known in the art. It will be appreciated that loading an APS film cassette into a single use APS camera presents special problems. The light lock door cannot be opened in non-darkroom conditions without exposing the film in the cassette, and thus conventional techniques used to preload 35 mm single use cameras cannot be employed unless film loading and final camera assembly take place in darkroom conditions. Prior art methods of loading film into single use APS cameras include performing the following steps in darkroom conditions, with the back cover of the camera removed: opening the light lock door of the cassette by inserting a tool or fixture into the light lock door spindle of the film cassette to rotate the light lock door to the open position before the cassette is placed in the camera; inserting a tool or fixture into the film spool spindle of the film cassette to drive a leader portion of the film from the cassette by rotating the spool inside the cassette with the tool or fixture; placing the cassette in a film cassette compartment of the camera; winding unexposed film from the cassette into a spool in a film spool compartment of the camera; then, assembling the back cover to the camera. If the camera requires a battery, then depending on the construction of the camera, the battery may have to be loaded in darkroom conditions as well. Thus, loading film into a single use camera may be cumbersome, time consuming and labor intensive. An improved method of loading film and a battery into an APS single use camera in non-darkroom conditions is described in the 733 and 311 patents. 
     Single use APS cameras usually automatically close the light lock door on the film cassette after all of the film has been rewound back into the cassette. This is usually done by means of a film sensor or other mechanism. Therefore, one issue that must be addressed in designing an APS camera is that of closing the light lock door of the film cassette after all of the film has been rewound into the film cassette. (In reusable APS cameras, this issue also entails preventing opening of the film cassette door until the light lock door has been closed.) In order to determine when to close the light lock door, there must be provided some indication that the film has been rewound into the film cassette. Typically, an APS camera employs a film sensor for this purpose. The function of the film sensor is to sense the presence or absence of film in the film path disposed between the film cassette compartment and the film spool compartment. The film sensor typically extends into the film path and rests against the film when film is present in the film path, thus detecting the presence of film outside of the film cassette. When film is no longer present at the film path location where the sensor is disposed, the absence of film is detected and it is assumed that all film has been wound into the film cassette. This causes the light lock door to close either automatically or upon further rotation of the film advance wheel. See, for example, U.S. Pat. No. 5,600,395 and the 733 and 311 patents. Generally, the film sensor presses against the film when film is present in the film path and thus exerts a force on the film in a direction transverse to the direction of travel of the film. Moreover, this force exists at all times that the film is present, including when the film is in motion, and may cause the film to deflect transverse to its direction of travel. Observation has shown that the action of the film sensor pressing against the film while the film is wound into the film cassette (i.e., after an exposure has been taken) may cause damage to or deterioration of the film because the film might rub against an internal surface of the camera or because the action of the film sensor rubbing against the film may cause damage to or deterioration of the film. 
     It is therefore desirable to provide a single use APS camera that is simple to preload with film and which can be easily preloaded in non-darkroom conditions. It is also desirable to provide an APS camera wherein the film sensor is prevented from applying potentially damaging forces to the film. The present invention addresses these goals. 
     SUMMARY OF THE INVENTION 
     An APS camera has an aperture in its body that opens to the exterior of the camera and light tightedly provides access to a light lock door driver and a film sensor mounted within the camera. A preloading tool is used to manipulate, via the aperture, the light lock door driver so as to open the light lock door and to move the film sensor out of the film path. The preloading tool includes, at one end, a movable member for operating the light lock door driver and a fixed member for operating the film sensor. The other end is for manipulation by a user. The camera&#39;s film advance mechanism is used to thrust film from the film cassette, into the film path, and into a film spool compartment after the light lock door has been opened and while the film sensor is held out of the film path. A winding tool is used to spool the film in the film spool compartment so as to pre-wind the film therein. 
     The light lock door driver is spring biased to urge the light lock door to a closed position, but is prevented from doing so due to interference from the film sensor when the film sensor is in a first position indicating that film is present in the film path. In addition, a brake is normally applied to the film sensor to prevent it from pressing against the film (and thus preventing it from sensing the presence or absence of film in the film path), except during a brief sensing interval that occurs during a short period of rotation of the film advance wheel. During the sensing interval, the brake is released and the film sensor is permitted to momentarily sense the presence or absence of film in the film path. If film is sensed, the brake is reapplied at the end of the sensing interval. If the absence of film is sensed, the film sensor moves to a second position (into the film path) wherein it no longer interferes with the light lock door driver, whereupon, due to the spring biasing, the light lock door driver rotates the light lock door to the closed position. 
     Other features of the invention are described below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of one preferred embodiment of a single use APS camera according to the invention, showing one form of packaging that may be applied thereto in dotted lines. 
     FIG. 2 is a rear perspective view of the camera of FIG.  2 . 
     FIG. 3 is a diagrammatical view of an interior portion of one embodiment of the camera of FIG.  1  and illustrates, in part, a light lock door driver and film sensor, and a preloading tool cooperating with the light lock door driver and film sensor to urge the same to a film preloading position. 
     FIG. 4 is a perspective view of the distal end of the preloading tool, showing one portion therof extended relative to another portion. 
     FIG. 4A is a side elevation of the preloading tool of FIG. 4, showing the distal end thereof in cross section. 
     FIG. 5 is a plan view of the distal end of the preloading tool of FIG. 4 
     FIG. 6 is a rear plan view of the camera of FIG. 1, with a portion of that side of the camera containing the film cassette being shown in a partial cut-away view. 
     FIG. 7 is a rear plan view of the camera of FIG. 1 with the back cover thereof removed, and illustrates a stage of camera preloading wherein film extends from the film cassette part way into the film path. 
     FIG. 8 is a rear plan view of the camera of FIG. 1 with the back cover removed, and illustrates the film extending from the film cassette, fully across the film path and into the film spool compartment, and further illustrates a winding tool inserted into the film spool compartment to wind film therein. 
     FIG. 9 is a cross section taken through line  9 — 9  of FIG.  7  and illustrates an initial stage of a film preloading procedure wherein the preloading tool is first inserted into the aperture of the camera but has not yet manipulated the light lock door driver to the light lock door open position. 
     FIG. 10 is a cross section taken through line  9 — 9  of FIG.  7  and illustrates a further stage of a film preloading procedure wherein the preloading tool has manipulated the light lock door driver to the light lock door open position; in FIG. 10, the film from the film cassette is shown as partially extending into the film path, but not yet reaching the film spool compartment. 
     FIG. 11 is a cross section taken through line  9 — 9  of FIG.  7  and illustrates yet a further stage of a film preloading procedure wherein the light lock door is held in the light lock door open position with the preloading tool, and the tool has also been manipulated to move the film sensor out of the film path and so as to interfere with the light lock door driver; in FIG. 11, the film from the film cassette is shown wound in a spool in the film spool compartment. 
     FIGS. 12,  13 ,  14  and  15  illustrate use of the preloading tool to manipulate the light lock door driver and film sensor, and particularly how the preloading tool is used to rotate the light lock door driver from a light lock door closed position (FIG. 12) to a light lock door open position (FIG. 14) and to move the film sensor from a first position (FIG. 12) to a second position that is out of the film path (FIG.  15 ). 
     FIG. 16 illustrates the cooperation between the film advancing mechanism and the film cassette. 
     FIG. 17 is a side plan view of those details of the camera illustrated in FIG. 3, and further illustrates movement of the film sensor between the first (dotted line) and second (solid line) positions. 
     FIGS. 18,  19 ,  20 , and  21  are a partial cross section, i.e., of the right hand side (film cassette compartment side), taken through line  9 — 9  of FIG. 7, with a portion of the advance wheel cut away to reveal additional details, and to show a sequence of events during a film rewinding procedure. 
     FIG. 22 is a cross section taken through line  22 — 22  of FIG.  18  and illustrates coupling of the light lock door driver and film advancing mechanism to the film cassette. 
     FIG. 23 illustrates the camera of FIG. 1 with its back cover removed and illustrates interior details of the back cover and main body of the camera. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, wherein like numerals represent like elements, there is illustrated in FIGS. 1 and 2, one embodiment of a camera  10  that may incorporate the present invention. Preferably, camera  10  is a single use APS camera having a main body  26  (e.g., FIG. 7) sandwiched between a front cover  12  and a back cover  14  light tightedly sealed together. Camera  10  may have packaging (as herein defined)  102  , as is common. Camera  10  may be provided with a first port  16  on the underside thereof for receiving an APS film cassette  18  therethrough for loading into a film cassette compartment, and a tab  20  for light tightedly sealing the film cassette compartment  28  after the cassette  18  has been received therein. Alternatively, cassette  18  may be loaded into camera  10  before the back cover  14  has been applied thereto, with the back cover  14  being applied so as to light tightedly seal the camera  10  after cassette  18  has been inserted into the camera. Either way, the method of the present invention involves preloading camera  10  with film from cassette  18  with the back cover  14  affixed to the camera  10  and such that camera  10  is substantially light tight. Camera  10  may also be provided with a second port  88  for receiving a winding tool  100  (FIG. 8) inside a film spool compartment  30  to facilitate prewinding. A second tab  92  may be provided for light tightedly sealing the film spool compartment after prewinding has been completed. Tabs  20  and  92  may be applied by mechanical means such as tongue and groove fastening, snap fit, etc., or may be adhesively bonded, thermally bonded, etc. 
     Camera  10  has a film path  36  disposed between the film cassette compartment  28  and the film spool compartment  30 . See FIGS. 7 and 10. Film path  36  includes a pair of opposed, spaced apart rails  38  (FIGS. 7,  8 ), and thus film path  36  is defined longitudinally by the distance between the film cassette compartment  28  and the film spool compartment  30  and laterally by the distance between spaced apart rails  38 . A tubular spool  34  having a film slot  72  for receiving a leading edge  80  of film  32  may be provided in film spool compartment  30 . As more fully described in the 733 and 311 patents, slot  72  and film path  36  are designed such that no meaningful amount of light can enter the film path  36  to expose film  32  via slot  72 . As also explained therein, once the leading edge  80  has been inserted into the slot  72  and the spool  34  has been rotated slightly, no light is permitted to enter the film path  36  or to expose any film wound on the film spool  34 . Prior to application of tab  92 , a winding tool  100  may be inserted into spool  34  to prewind film from the cassette  18 . Additional details of the camera thus far described are available in the 733 and 311 patents, and reference is made thereto for such details. Thus, once cassette  18  has been sealed within the camera  10 , the light lock door thereof may be opened without fear of exposing film in the cassette  18  or in any substantial portion of the film path  36 , even though the second port  88  remains open, thus permitting use of a preloading and prewinding method that can be performed in non-darkroom conditions. The 733 and 311 patents teach one such method. According to the present invention, another such method is enabled. 
     Disposed in the back cover  14  is an aperture  22  in substantial alignment with a portion  64  of a light lock door driver  40  disposed in the camera and also in substantial alignment with a portion  68  of a film sensor  46  disposed on the main body  26  of camera  10 . See FIGS. 2 and 23 for the aperture  22 ; see FIGS.  6  and  9 - 11  for the alignment of elements  64  and  68  with aperture  22 . Aperture  22  is adapted to receive a pair of members  94 ,  96  disposed at a distal end of a preloading tool  90  as shown in FIGS.  3  and  9 - 11 . Ambient light is prevented from entering the film cassette compartment  28  or film path  36  via aperture  22  by means of rails  38  and additional mating surfaces disposed on the main body  26  and inside of the back cover  14  so as to create a light tight seal and light tightedly envelop the film path  36 . See, e.g., FIGS. 6,  7  and  23 . 
     A manually rotatable advance wheel  24  has a shaft  82  adapted to cooperate with film spool spindle  44  of film cassette  18 . Similarly, light lock door driver  40  has a shaft  84  adapted to cooperate with the light lock door spindle  42  of film cassette  18 . See, e.g., FIGS. 2,  16  and  22 . Thus, when the light lock door of cassette  18  is open, rotation of wheel  24  in a clockwise direction (as seen in FIG. 3) will scroll film  32  out of the cassette, while rotation thereof in a counterclockwise direction will rewind film  32  back into the cassette. Light lock door driver is rotatably mounted to main body  26  by means of a pin  66  such that rotation of the light lock door driver  40  in a clockwise direction (as seen in FIG. 3) will open the light lock door, and rotation thereof in a counterclockwise direction (as seen in FIG. 3) will close the light lock door. (Note that pin  66  is located on the underside of driver  40 , and cannot be seen from the top of driver  40 . Element  66  shown in FIG. 3 is intended to show the placement of the pin beneath the driver  40 .) A spring  54  coupled to a post  52  disposed on the light lock door driver  40  and to a post  86  on the main body  26  biases the light lock door driver in a direction (counterclockwise in FIG. 3) that tends to close the light lock door. 
     As best shown in FIGS. 3,  16  and  17 , the lower end  62  of a film sensor  46  is mounted for partial rotation about a pin  48  coupled to the main body  26 . The film sensor  46  includes an integral molded plastic spring section  56  compressed against the main body  26  so as to bias the upper portion  60  of the film sensor  46  in a clockwise direction as seen in FIG.  17 . The film sensor  46  includes an integral film sensing finger  50  adapted to contact film  32  when present in the film path  36 , and adapted to be received into a recess  70  (FIG. 6) when no film is present in the film path  36 . Thus, when film  32  is present in the film path  36 , the film sensor  36  is in the position indicated in dotted lines in FIG. 17, and when no film is present in the film path  36 , the film sensor is in the position indicated by solid lines in FIG.  17 . In FIG. 17, reference numerals  50 ′,  56 ′ and  60 ′ indicate the position of those elements when film is present in the film path  36 . 
     Light lock door driver  40  has a portion  64  that includes a flat surface  65 . As best illustrated in FIGS. 3 and 18, when the light lock door driver has been rotated to a position corresponding to the light lock door open position (the position shown in FIGS. 3,  16  and  18 ), surface  65  is urged against a side of the upper portion  60  of film sensor  46  by action of the spring  54 . Since the spring constant of spring  54  is greater than that of spring  56 , the pressing of surface  65  against portion  60  of film sensor  46  prevents rotational movement of the film sensor. Thus, the force that would otherwise be applied by finger  50  to film  32  by action of spring  56  is overcome by the action of spring  54  causing surface  65  to press against upper portion  60 . Finger  50  is therefore prevented from applying the force that would normally be exerted by spring  56  against film  32 . Thus, surface  65  acts as a brake that prevents finger  50  from applying any meaningful pressure or force to film  32 . As will be appreciated, the brake also prohibits finger  50  from sensing the absence of film, since rotation of film sensor  46  is inhibited during the time that the brake is applied. 
     Integrally formed on the underside of wheel  24  is a cam  76 , as shown in FIGS.  16  and  18 - 21 . The cam is adapted to cooperate with a post  58  disposed on light lock door driver  40 . FIG. 18 represents the position of the cam  76  relative to the post  58  before an exposure has been taken. It will be seen that the surface  65  of portion  64  is urged against the portion  60  of the film sensor  46  by action of spring  54 , and hence the brake is applied. In FIG. 19, the film advance wheel has been slightly rotated in a counterclockwise direction so as to begin rewinding of the film into the cassette one frame after the taking of an exposure. It will be seen that the cam  76  has also rotated a slight amount so as to contact the post  58 . This causes a slight rotation of light lock door driver  40  in a clockwise direction, such that surface  65  is removed from contact with portion  60 . At this juncture, the brake has been removed, and finger  50  is free to sense the presence or absence of film  32  in the film path  36 . This initiates a film sensing interval. In FIG. 20, the wheel  24  has been further rotated in a counterclockwise direction to continue the rewinding of one frame of film into the cassette. Cam  76  continues to advance relative to post  58  such that spring  54  returns light lock door driver  40  to a position where surface  65  again contacts upper portion  60  of the film sensor and again applies the brake. Thus, re-application of the brake has ended the sensing interval. Camera  10  may be designed so that only one 360° rotation of the manual advance  24  is required to wind one frame of film  32  into cassette  18 , thus preventing multiple sensing intervals during the rewinding of a single frame. However, this is not necessary, and several sensing intervals may occur during the rewinding of a single frame. Importantly, however, finger  50  is prevented from applying the force that would normally be applied by reason of spring  56  during the entire time that film is being rewound into the cassette. It will thus be appreciated that, as long as film  32  is present in the film path, the film sensor  46  will remain in the position illustrated in dotted lines in FIG. 17, and the upper portion  60  will interfere with the rotation of the light lock door driver  40  in the counterclockwise direction, so as to prevent closing of the light lock door. However, if during the sensing interval illustrated in FIG. 19, no film were detected in film path  36 , spring  56  would urge film sensor  46  to the position illustrated in solid lines in FIG. 17 such that the upper portion  60  would no longer interfere with the counterclockwise rotation of light lock door driver  40 . Hence, light lock door driver  40  will be free to rotate counterclockwise by action of spring  54 , until the light lock door has been fully closed, as shown in FIG.  21 . 
     There has been described so far a structure for camera  10 , including a brake, that prevents the film sensor from applying potentially damaging forces to film  32  during the entire time that film is being rewound into the cassette during a film rewind procedure. There has also been described a method of operation of such a brake sensing structure after film has been preloaded into the camera  10 . There will now be described a tool for manipulating the light lock door driver  40  and film sensor  46  so as to permit film preloading in non-darkroom conditions, and a method for loading film into the camera using the tool in non-darkroom conditions. 
     Preloading tool  90  has a handle portion  74  at a proximal end thereof and a pair of members  94 ,  96  at a distal end thereof. Member  94  is fixed relative to the handle  74 . Member  96  is slideable between first and second positions by means of knob  98 . As shown in FIG. 4, the end of slidable member  96  has a beveled edge  96 ′, whereas fixed member  94  has a portion  94 ′ that is stepped down at a distal end so as to create a shoulder  94 ″. Member  94  is adapted to cooperate with portion  64  and a projecting member of  78  of light lock door driver  40 , and member  96  is adapted to cooperate with surface  68  of portion  60  of film sensor  46 . Particularly, as best illustrated in FIGS.  3  and  9 - 15 , to preload camera  10  according to the method of the present invention, member  94  is inserted into aperture  22  so that the distal end  94 ′ thereof contacts projecting member  78  disposed on the underside of light lock door driver  40 . The tool  90  is then pushed toward the back cover  14  of the camera (into the camera) so as to rotate the light lock door driver  40  in a clockwise direction as seen in FIGS. 9-11, until the light lock door driver  40  has been rotated to the position indicated in FIG.  10 . An internal stop may be provided to prevent further rotation of light lock driver  40  beyond the position shown in FIG.  10 . It will be appreciated that the shoulder  94 ″ will contact the portion  64  of light lock door driver  40  so as to allow continued rotation of the light lock door driver  40  after projecting member  78  has been rotated out of contact with the distal end  94 ′ of member  94 . In the position shown in FIG. 10, the light lock door of film cassette  18  has been opened. Next, the slidable member  96  is extended by means of knob  98  so that the distal end of member  96  contacts surface  68  of the upper portion  60  of film sensor  46 . Continuing to extend the member  96  urges the finger  50  out of the film path  36  (e.g., to the position shown in dotted lines in FIG.  22 ). With the light lock door open and the finger  50  out of the film path  36 , the manual advance wheel  24  is rotated in a clockwise direction (as seen in FIG. 10) to thrust film out of the cassette and into the film path  36 . The film advance wheel is continued to be rotated until the film  32  is received into slot  72  (which has been previously oriented so as to receive the leading edge  80  of film  32 ). Thereafter, film winding tool  100  is inserted into the spool  34  and film is prewound into the film spool compartment to complete the preloading process. It will be appreciated that the preloading tool may be removed from aperture  22  after the film  32  has been received into the slot  72 , since the brake will be applied to the film sensor as described above once the tool has been removed and the prewinding process may occur without fear of the finger  50  damaging the film. 
     There has been described a camera having a brake that prevents the application of potentially damaging forces to the film by the film sensor during both a preloading process (i.e., during prewinding) as well as during rewinding of the film into the cassette after each exposure has been taken. There has also been described a structure for implementing a sensing interval, occurring briefly during a film rewind procedure, during which time the film sensor is permitted to momentarily sense the presence or absence of film in the film path  36 . There has been further been described a novel preloading procedure wherein camera  10  may be preloaded in non-darkroom conditions, including a tool for enabling such method. It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of the parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.