Abstract:
A display unit ( 12 ) is provided, the display unit including a housing ( 20 ) configured for mounting in an interior region of a vehicle, and a screen ( 30 ) mounted on the housing for movement between a stowed position wherein the screen is at least partially contained within the housing and a deployed position wherein the screen projects from the housing to reveal a viewing surface ( 32 ) of the screen. When the screen is deployed, the viewing surface typically is at an angle of between 45-degrees and 90-degrees from the stowed position.

Description:
This application is a 371 of PCT/US/99/30993, filed on Dec. 28, 1999, which claims benefit of 60/113,876, filed on Dec. 28, 1998. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to a video display system, and, more particularly, to a video display system which is mountable in a vehicle and also removable for use outside the vehicle. 
   2. Discussion of the Related Art 
   Televisions and video cassette players have recently become quite popular in motor vehicles as a means of providing entertainment for both children and adults. Such devices, for the most part, however, have been limited to use in larger vehicles such as sport utility vehicles, mini-vans, and full size vans due to the space requirements for conventional televisions and video cassette players. Such systems have often been mounted in a console on the floor of a vehicle, as well as to the headliner of a vehicle. In either mounting, such systems require a significant amount of space. Also, such systems have typically not been removable easily from the vehicle for use outside the vehicle with an AC power source. 
   More recently advances in Liquid Crystal Display (LCD) panels have significantly improved the picture and contrast afforded by these types of displays, making them suitable for use in a wide variety of applications. LCDs are much thinner than conventional cathode ray tubes (CRTs) and therefore require significantly less space than a conventional television employing a CRT as a picture tube. LCDs are also much lighter in weight than CRTs, therefore making them readily portable, as evidence by the popularity of laptop computers. The lightweight and compact configuration of an LCD panel would therefore enable it to easily be mounted in various interior areas of a motor vehicle such as a sport utility vehicle, truck, van, or car, where the mounting of a video screen having a CRT would not be possible because of space constraints. 
   Even more recently, Digital Video Disc (DVD) players have become increasingly popular. DVD players are significantly more compact than video cassette players, lighter in weight, generate less heat and offer significantly enhanced picture and sound quality over a VHS format videocassette. The extremely compact dimension of a DVD, which is essentially the same as a compact disc, further enables the dimensions of the DVD player to be kept very compact. DVD players are not limited to playing video discs, but can also play compact discs as well. 
   In view of the foregoing performance and compact size advantages offered by LCD panels and DVD players, it would be highly desirable to incorporate both such devices into an integrated LCD/DVD unit which could be easily mounted within a motor vehicle such as a car, sport utility vehicle, van, mini-van, or truck. More preferably, it would be highly desirable to incorporate an integrated LCD/DVD unit into a console in such a manner that the LCD/DVD unit can be quickly and easily moved into a viewable position, such as flipped down from a headliner mounted console, and also easily moved into a stowed position so that it is out of the way when not in use. 
   It would further be highly desirable to provide an LCD/DVD player which can be quickly and easily removed from its associated console so that the entire unit can be used outside of the vehicle with an alternate AC or DC power source. 
   SUMMARY OF THE INVENTION 
   The present invention relates to an integrated visual display/digital media player in the form of an integrated LCD/DVD unit or video display system and a docking member which is movably mounted within a console. The video display system can be used to watch material contained on digital video discs or to play compact discs, provided speakers are coupled to the video display system. 
   In one preferred embodiment, the video includes a housing and a screen console having a screen. The screen console is moveable between a first position and a second position. A digital video disc player is simultaneously integrally positioned within one of the housing and the screen console and operably connected to the screen. 
   In another preferred embodiment the video display system is releasably coupled to the docking member. The docking member is in turn movably coupled to the console. The console may be mounted at many places within the vehicle, but in the preferred embodiment is mounted to the headliner of the vehicle. A latch on the back of the docking member automatically holds it in a retracted or “stowed” position when the unit is inserted into the docking member and then folded up into the console. Latch assemblies on the video display system releasably secure it to the docking member yet permit the unit to be easily uncoupled from the docking member and removed for use outside of the vehicle. 
   The present invention requires only a small portion of the space required by a television having a cathode ray tube and a video cassette player. When in the stowed position, the video display system is held within its associated console and forms an unobtrusive system which does not interfere appreciably with the driver&#39;s vision out of the rear of the vehicle, when mounted in the headliner. The system, however, is compact enough to readily permit mounting in outer areas, such as the rear of the two front seats or on a floor mounted console. 
   In addition, the smaller packaging and footprint of the present invention make the video display system easier to incorporate into various styles and types of vehicles. 
   In addition, the video display system of the present invention can be removed from the docking station which is located in the headliner and placed in another docking station which is located remote from the vehicle. This enables the video display system to be used for entertainment when at a location outside the vehicle. Further, the video display system may also incorporate a television tuner and/or cable adapter so as to allow the video display system to display television programs. 
   Other objects and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description and upon reference to the following drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various advantages of the present invention will become apparent to one skilled in the art upon reading the following specification and by reference to the drawings in which: 
       FIG. 1  is a front perspective view of a preferred embodiment made in accordance with the teaching of the present invention; 
       FIG. 2  is a rear perspective view of the embodiment shown in  FIG. 1  made in accordance with the present invention; 
       FIG. 3  is an exploded view of the preferred embodiment shown in  FIG. 1  made in accordance with the present invention; 
       FIG. 4  is a front perspective view of an alternative preferred embodiment made in accordance with the present invention; 
       FIG. 5  is an exploded view of the embodiment shown in  FIG. 4  made in accordance with the present invention; 
       FIGS. 6   a  and  6   b  are alternative embodiments of the housing of the embodiment shown in  FIG. 4  made in accordance with the present invention; 
       FIGS. 7   a – 7   c  are side views of the latch mechanism of the embodiment shown in  FIG. 4  made in accordance with the present invention; 
       FIG. 8   a  is a front view of a stand operable with the embodiment shown in  FIG. 4  made in accordance with the present invention; 
       FIG. 8   b  is a side view of the stand shown in  FIG. 8   a  made in accordance with the present invention; 
       FIG. 9  is a front perspective view of a tuner stand operable with the embodiment shown in  FIG. 4  made in accordance with the present invention; 
       FIG. 10  is a perspective view of an alternative embodiment of the present invention shown in  FIG. 4  made in accordance with the present invention; 
       FIG. 11  is an exploded view of the embodiment shown in  FIG. 10  made in accordance with the present invention; 
       FIG. 12  is a front perspective view of the housing of the embodiment shown in  FIG. 10  made in accordance with the present invention; 
       FIG. 13  is a perspective view of the embodiment shown in  FIG. 10  made in accordance with the present invention; 
       FIG. 14  is a perspective view of the embodiment shown in  FIG. 10  made in accordance with the present invention; 
       FIG. 15  is a perspective view of the embodiment shown in  FIG. 10 ; 
       FIG. 16  is a front perspective view of an alternative preferred embodiment made in accordance with the present invention; and 
       FIG. 17  is an exploded view of the embodiment shown in  FIG. 4  made in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following description of the preferred embodiments is merely exemplary in nature, and are in no way intended to limit the invention or its application or uses. Moreover, while the detailed description discloses a specific vehicle interior trim component embodiment, one skilled in the art will recognize that any vehicle interior trim component could incorporate the present invention. 
   Referring to  FIGS. 1 and 2 , a video display system  30  is shown. The video display system  30  includes a digital video disc (DVD) player  32  that is integrated in a housing  34 . The housing  34  also includes a plurality of controls  36  that allow a user to operate the DVD player  32 . A screen console  38  having a screen portion  40  is rotatably mounted to the housing  34 . Releasing a latch mechanism  42  allows the screen console  38  to rotate from a first or closed position  44  to a second or open position  46 . The latch mechanism  42  is positioned substantially on the screen console  38  engageable with a portion of the housing  34 . Alternatively, the latch mechanism  42  can be positioned substantially on the housing  34  engageable with a portion of the screen console  38 . A plurality of audio connectors  48  is also integrated with the housing extending from the housing such that a user could connect speakers, headphones, or other conventionally known listening devices to the video display system  30 . 
   Although the video display system  30  is depicted in  FIGS. 1 and 2  as being mounted to a headliner of a motor vehicle interior, it will be appreciated by one of ordinary skill in the art that the video display system  30  could be mounted in several areas of a vehicle, including, but not limited to, a seat back, a floor console, a center armrest console, etc. Additionally, the video display system  30  is not limited to automotive applications. The video display system could easily be incorporated into similar components within the cabin of a boat, aircraft, etc. 
   Referring to  FIG. 3 , the components of the video display system  30  are shown. The housing  34  includes a retainer portion  52  and a bezel portion  54 , with a vehicle interface wiring harness  56  extending through the retainer portion  52  and the bezel portion  54  including a plurality of apertures  55 . The plurality of apertures  55  are positioned accordingly on the bezel portion  54  in order to accommodate digital video discs and the plurality of controls  36 . Several components are integrated in the bezel portion  54  and the retainer portion  52  of the housing  34 . These components include the DVD player  32 , a disk wiper assembly  58 , and a power supply  60 . Additionally, printed circuit boards  62  are integrated into the housing  34  providing, among other things, a user input and output interface with the audio connectors  48  and the plurality of controls  36 . Each of the components are fixedly secured within the housing. In a preferred embodiment, threaded fasteners  64  are used for this purpose. However, one of ordinary skill in the art will appreciate that other types of fasteners could be used with equal results and, therefore, are within the scope of this disclosure. Additionally, each component is operatively associated with the other components in any known conventional manner such that the DVD player functions as it is intended and, therefore, is also within the scope of one of ordinary skill in the art. 
   In  FIG. 3 , the first latch mechanism  42  includes a latch portion  66  and a latch spring  68  operatively associated with the bezel portion  54  of the housing  34  in order to retain the screen console  38  in a first or closed position  44 . Alternatively, the first latch mechanism  42  could be positioned within the screen console  38  and operatively associated with the housing  34  in order to releasably retain the screen console  38  within the housing  34 . 
   The screen console  38  includes a screen  40 , preferably a liquid crystal display, positioned within a rear cover  70  of the screen console and a front cover  72  of the screen console  38 . The screen console  38  is moveably associated with the housing  34 . In a preferred embodiment, the screen console  38  is rotatably or pivotally associated with the housing  34  through the use of a torque hinge  74 . The torque hinge  74  provides a smooth, constant, and controlled rotation of the screen console  38  from the first or closed position  44  to the second or open position  46  after the latch mechanism  42  is actuated by a user. One of ordinary skill in the art will appreciate that various types of hinge mechanisms can be used with equal results. Additionally, one of ordinary skill in the art will appreciate that the screen console  38  and screen  40  could be movably associated with the housing  34  such that the screen console moved from the first or closed position  44  to the second or open position  46  along an axial path after the latch mechanism  42  had been actuated. This type of movement would include, but is not limited to sliding in an upwardly or downwardly facing direction. 
   The screen  40  is also operatively associated with the components integrated in the housing  34  such that the DVD player  32  functions as intended in any conventionally known manner. Connecting the screen  40  in this manner is also within the skill of one of ordinary skill in the art. Additionally, conventionally known fasteners  64  are used to attach the torque hinge  74  to the housing  34  and the screen console  38 . Conventionally known fasteners  64  are also used to attach the front cover  72  to the rear cover  70  thereby retaining the screen  40  within the screen console  38 . 
   Also positioned on the screen console  38  is an infrared transmitter/receiver  76 . Alternatively, the infrared transmitter/receiver  76  could be positioned on the housing  34  with equal results. The infrared transmitter/receiver  76  is operable to receive control signals from a remote control device  78  actuated by the user and operable to send audio signals to remote locations including, but not limited to, infrared headphones and speakers. 
   In an alternative preferred embodiment, the video display system  30  components can be operably arranged and integrated into the screen console  38  forming a self contained video player unit  79  that is detachable from the housing  34 . This alternative preferred embodiment will now be described in greater detail with features corresponding to the features of the above-described embodiment being referenced using the same reference numbers and reference signs. 
   Referring to  FIG. 4 , the video display system  30  of an alternative preferred embodiment is shown. The video display system  30  includes a DVD player  32  and a screen  40  integrated in a screen console  38  forming a video player unit  79  releasably attached to a housing panel  80 . The housing panel  80  is moveably attached to the housing  34  and is operable to move between a first or closed position  44  and a second or open position  46 , as previously described with reference to  FIGS. 1–3 . The housing panel  80  also incorporates a first latch mechanism  42  that releasably retains the screen console  38  and the housing panel  80  in the first or closed position  44  and, when actuated by a user, allows the screen console  38  and the housing panel  80  to be released and moved to the second or open position  46 . In this embodiment, the screen  40  is a liquid crystal display. 
   Referring to  FIG. 5 , the screen console  38  is shown detached from the housing panel  80 . The screen console  38  includes a second latch mechanism  82  operatively associated with the panel housing  80  to releasably connect the screen console  38  to the housing panel  80 . In this embodiment, the screen console  38  also includes an infrared transmitter/receiver  76  operable to receive control signals from a remote control device  78  and operable to send audio signals to remote locations including, but not limited to, infrared headphones and speakers. Additionally, the screen console includes a plurality of controls  36  that allow the user to operate the DVD player and a slot  81  allowing insertion and removal of the digital video disc. The screen console  38  also incorporates an audio connector  86  and a corresponding audio control switch  88 . One of ordinary skill in the art will appreciate that the audio connector  86  is operable to receive a connector from headphones or speakers. 
   The screen console  38  in this embodiment also includes an auxiliary power connector  90 . Again, one of ordinary skill in the art will appreciate that this connector is operable to receive power from various types of remote sources including, but not limited to an alternating current power source (e.g. a conventionally known power outlet in a home), and a direct current power source (e.g. a automobile battery, a conventionally known battery, etc.). Additionally, a rechargeable battery can be integrated in the screen console  38  providing power to the video player unit  79  when the video player unit  79  is detached from the housing panel  80  and being used in a portable capacity. The rechargeable battery recharges using the vehicle&#39;s electric power supply when the video display unit  79  is attached to the housing panel  80 . As can be seen in  FIG. 5 , the housing panel  80  also includes a wiring harness connector  92  operable to engage a corresponding wire harness connector  93 , as shown in  FIGS. 7   a – 7   c , positioned on a rear side of the screen console  38 . 
   Although this embodiment is shown mounted to a headliner  50  of an automobile, it is within the scope of this disclosure that this video display system  30  could also be mounted to other interior components located within the automobile, including, but not limited to, seat backs, center consoles, etc. 
   Referring to  FIG. 17 , the components of the video display system  30  of the alternative preferred embodiment shown in  FIGS. 4 and 5  are shown. The housing  34  includes a retainer portion  52  attached to a bezel portion  54  using threaded fasteners  64 . The housing  34  is attached to an interior trim component of a vehicle using at least one attachment clip  180 . Although threaded fasteners  64  are used in this embodiment, it is specifically contemplated and, therefore, within the scope of this disclosure, that the retainer portion  52  and the bezel portion  54  can be attached together through any conventionally known means including, but not limited to, other types of fasteners and attachment brackets molded into the retainer portion and/or the bezel portion  54 . 
   The housing panel  80  includes a display carrier portion  182  and a display carrier trim portion  184  fastened to each other using the means previously described. The housing panel  80  is moveably associated with the housing  34 . In this preferred embodiment, the housing panel  80  is rotatably or pivotally attached to the housing  34  through the use of a torque hinge  74 . The torque hinge  74  provides a smooth, constant, and controlled rotation of the housing panel  80  from the first or closed position  44  to the second or open position  46  after the latch mechanism  42  is actuated by a user. One of ordinary skill in the art will appreciate that various types of hinge mechanisms can be used with equal results. In this embodiment, the first latch mechanism  42  including a latch portion  66  and a spring latch  68  is positioned substantially on the housing panel  80  and operatively associated with the bezel portion  54  of the housing  34  in order to retain the screen console  38  in a first or closed position  34 . 
   The screen console  38  includes a screen  40  and a DVD player  32  positioned substantially within a front cover  72  and a rear cover  70 . The DVD player  32  and the screen  40  are positioned parallel to one another, and as both are integrated into the single unit screen console  38 , pivot or rotate through the same arc or motion as the housing panel  80  moves from the first or closed position  44  to the second or open position  46 . 
   Additional components are also positioned substantially within the rear cover  70  and the front cover  72  of the screen console  38 . All of the components in this embodiment are operatively associated with each other in order to allow the DVD player to function as intended. These components include a plurality of printed circuit boards  62  providing input and output interfaces with a plurality of controls  36 , audio connectors  86 , power connectors  82 , etc. A disc wiper assembly  58  and a screen inverter  186  are also provided within the screen console  38 . In this embodiment, the infrared transmitter/receiver  76  and the infrared lens  192  are positioned on the front cover  72  while the second latch mechanism  82  and the wiring harness connector  93  are positioned on the rear cover  70 . The latch mechanism includes a latch portion  188  and a spring portion  190 . The wiring harness connector  93  corresponds to a wiring harness connector  92  positioned substantially within the housing panel  80 . 
   The alternative embodiment described in  FIGS. 4 ,  5 , and  17  may also be provided in a manner such that the screen console  38  is not removable from the housing panel  80 , as shown in  FIG. 16 . In this embodiment, the positioning of the components of the video display system  30  is substantially similar to the positioning of the components shown in  FIG. 17 , the only difference being that the housing panel  80  and the screen console  38  are provided as a single unit without the screen console release feature described above. 
   Referring to  FIGS. 6   a  and  6   b , a front portion  94  of the bezel portion  54  of the housing  34  may incorporate additional comfort features, including, but not limited to at least one interior lighting system  96  and at least one interior climate control system  98 . Additionally, the front portion  94  of the bezel portion  54  may include the integration of a rear seat entertainment module  99  and/or other types of radio station selection control and volume control. 
   Referring to  FIGS. 7   a – 7   c , the second latch mechanism  82  will now be described in further detail. In  FIG. 7   a , the latch mechanism  82  includes a latch arm  100  rotatably mounted to the screen console  38  and integrally formed with a button portion  102  and an engagement portion  104 . The engagement portion  104  is operably associated with a detent  106  positioned in the housing panel  80 . When pressure is applied to the button portion  102 , the latch arm rotates removing the engagement portion  104  from the detent  106  releasing the second latch mechanism  82  from the panel housing  80 . The latch mechanism  82  also includes a retaining slot  108  integrally formed in the screen console  38 . The retaining slot  108  is engageable with a corresponding retaining finger  110  integrally formed in the panel housing  80 . When the engagement portion  104  of the latch arm  100  has been removed from the detent  106 , the retaining slot  108  of the screen console  38  can be disengaged from the retaining finger  110 , as shown in  FIG. 7   b . This facilitates removal of the screen console  38  as shown in  FIG. 7   c.    
   One of ordinary skill in the art will appreciate that several variations of this latch mechanism  82  can be used with equal success and, therefore, are within the scope of this disclosure. These include, but are not limited to, positioning the latch arm  100  horizontally with the engagement portion  104  engaging a detent  106  correspondingly positioned in the housing panel  80 , and forming the latch mechanism  82  with the latch arm  100 , the button portion  102 , and engagement portion  104  such that an angle is formed with respect to the positioning of the rotatably mounted latch arm  100  and the engagement portion  104 . 
   Referring to  FIGS. 8   a  and  8   b , a stand  112  is shown. The video display system  30  of the present invention can be removed from the housing  34  and operably positioned within the stand  112 . The stand  112  may include at least one speaker  114  and a power switch  116 . The video display system  30  is releasably retained using the second latch mechanism  82  in the same manner as described above. The stand  112  includes a rear leg  118  rotatably attached to the stand  112 , thereby providing support so that the video display system can be substantially vertically positioned for viewing. The stand  112  has a wiring harness connector  92  engageable with a wiring harness connector  93  positioned in the screen console  38  as described above providing the required power, audio, etc., connections necessary for operation. 
   Referring to  FIG. 9 , the screen console  38  can also be positioned on a tuner  120  and operated either as a DVD player or as a screen for conventionally known TV and cable TV. The tuner also includes connectors for cable, audio, video, and power hookups, shown generally at  122 . Additionally, the tuner includes speakers and audio and channel controls shown at  124  and  126 . 
   Referring to  FIG. 10 , there is shown a video display system  130  in accordance with an alternative embodiment of the present invention. The video display system  130  comprises a liquid crystal display (LCD) screen  132  and a digital video disc (DVD) player  134  integrated in a single housing, referred to hereinafter as the LCD/DVD unit  136 . The LCD/DVD unit  136  is removably coupled to a docking member  140 , which is in turn pivotably connected to a console  142 . The console  142  may be mounted in a number of different areas but in this example is mounted to a headliner  144  of a motor vehicle interior  146 . It will be appreciated immediately, however, that the apparatus  130  could just as easily be mounted to a floor console of the vehicle or even on the back of one of the front seats of the vehicle. The apparatus  130  is not limited to automotive applications, and could easily be used within the cabin of a boat or aircraft if desired. 
   The LCD/DVD unit  136  includes a plurality of controls including a play switch  148 , a rewind or search backward switch  150 , a fast forward or search forward switch  152  and a pause or still switch  154 , A menu control switch assembly  156  enables menu functions to be selected on the display  132 . 
   The compactness of the LCD/DVD unit  136  allows the unit to be readily mounted in a wide variety of areas of a vehicle where a television incorporating a conventional cathode ray tube (CRT) and associated video cassette player would be much to bulky to mount. The entire apparatus  130  is also much lighter in weight, making to easier to secure in overhead areas of a vehicle interior, where a CRT might require significant modifications to the vehicle interior to support the greater weight of a CRT and video cassette player combination. 
   With further reference to  FIGS. 10 and 11 , the LCD/DVD unit  136  includes a molded plastic housing  158 . An upper portion  160  of the housing  158  includes an electrical connector (not shown) for coupling with a mating connector  162 , shown in  FIG. 12 , disposed within the docking member  140 . The connectors enable power to be provided to the LCD/DVD unit  136 . Connectors suitable for this purpose are of the “drawer” type and are commercially available from a wide variety of manufacturers, such as the AMP Corporation. 
   With further reference to  FIG. 10 , the console  142  includes a cavity or recess  164  sufficiently deep to hold the LCD/DVD unit  136  therein. A scalloped portion  166  provides an access point where an individual can insert one or more fingers and pull the LCD/DVD unit  136  down into the position shown in  FIG. 10 . 
   Referring to  FIGS. 10 and 14 , the docking member  140  is pivotably mounted to the console  142  at point  168  ( FIG. 15 ) on opposite sides of the console  142 . The LCD/DVD unit  136  can be held in the closed position by any form of spring biased latch which engages within a recess or notch on the docking member  140  to hold the unit  136  up in the recess  164  once the docking member is urged into the closed position.  FIG. 5  also illustrates a power supply  170  for providing power to the LCD/DVD unit  136 . The power supply  170  is shown attached to a rear surface  172  of the console  142 , although it will be appreciated that this could just as easily be enclosed within a portion of the console  142 .  FIG. 6  illustrates a slot  174  of the DVD player  176  which receives digital video discs for playback in the LCD/DVD unit  136 . 
   With further reference to  FIG. 10 , a spring loaded latch  178  is positioned on opposite sides of the housing  158  near the upper end  160  thereof. The latches permit the LCD/DVD unit  136  to be quickly detached from the docking member  140  when it is desired to remove the unit  136  from the vehicle. In this manner, the LCD/DVD unit  136  can be used outside the vehicle provided a suitable AC or DC power source is available. 
   The apparatus  130  of the present invention thus provides a compact means for playing back and viewing digital video discs. The light weight and compact configuration of the apparatus  130  enables it to be mounted at a variety of areas within a vehicle where it would be impossible or impractical to mount a television having a CRT and an associated videocassette player. The apparatus  130  is quickly and easily removable and light enough to be easily carried about and used outside of the vehicle within which its console is mounted. For example, the apparatus  130  may be removed from the vehicle and placed in another docking station which is located externally of the vehicle. In addition, the apparatus  10  may include other features such as a television tuner and/or a cable adapter to enable television programs to be used. 
   While the above-described embodiments disclose using a liquid crystal display for the screen  40 , it is specifically contemplated and, therefore, within the scope of this disclosure that other types of screens could be used with equal results, including, but not limited to, filled emission displays, organic light emitting diode displays, poly light emitting diode displays, etc. 
   The foregoing discussion discloses and describes a preferred embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications, and variations can be made therein without departure from the true spirit and fair scope of the invention as defined in the following claims.