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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   An awning cover for a slide out unit found on recreational vehicles, mobile homes and the like includes a canopy and scissors-type support arms which extend as the slide out unit is extended from the main body of the vehicle. The scissors arms are mounted at a bias so that a support bar across the underside of the canopy is raised as the awning cover is extended and lowered as the awning cover is retracted with the slide out unit. 
   2. Description of the Relevant Art 
   Mobile homes have been a mainstay for housing for many years, and in more recent years, motor home type structures have been used and are referred to as recreational vehicles. Similarly, trailers incorporating features of a recreational vehicle are becoming more popular and in each instance, it has become desirable to have the main body of the mobile home, recreational vehicle, trailer or the like expandable to selectively enlarge the living space within the vehicle. In order to accommodate such enlargement, mobile homes, recreational vehicles, trailers and the like are now sometimes provided with slide a out unit, which is a box-like structure having top and bottom walls as well as side walls and an outer wall with the box-like enclosure being motor driven between a retracted position within the interior of the vehicle and an extended position away from one side of the vehicle. 
   A common problem encountered with slide out units resides in the fact that debris, such as leaves, dust, dirt or the like will accumulate on the top wall of the slide out unit when the unit is extended. And when the unit is subsequently retracted, the debris is brought into the interior of the vehicle. To avoid debris being brought into the vehicle during a retraction of a slide out unit, covers have been provided over the top of the unit which extend along with the slide out unit and also retract with the unit. Any debris accumulating on the cover is therefore discarded as the unit retracts and the cover is rolled into a housing mounted on the side of the vehicle. 
   An example of an extendable cover for slide-out units is found in U.S. Pat. No. RE 37,567, which is of common ownership with the present application, and while overcoming some problems that were previously prevalent with the use of slide out units, have not been entirely satisfactory as the cover is flat when extended and generally coextensive with the top of the slide out unit so that debris, rain and the like will accumulate on the cover. 
   It is to provide improvements in awning covers for slide out units that the present invention has been developed. 
   SUMMARY OF THE INVENTION 
   An awning cover for a slide out unit on a mobile home, recreational vehicle, travel trailer or the like includes a canopy having one edge secured to the side of the vehicle and the other edge to an outer wall of the slide out unit. Either the inner or outer edge of the canopy is mounted on a retractable roll bar so that the cover can be extended with the slide out unit into an extended position covering the top of the slide out unit or retracted and wrapped around the roll bar when the slide out unit is retracted into the vehicle. 
   The canopy is supported between the inner and outer edges by scissors-type support arms which in turn support a support bar or rail extending longitudinally of the vehicle and intermediate the inner and outer edges of the canopy. The scissors arms are mounted on a bias so that as the slide out unit is extended from the vehicle and the awning canopy is unrolled from the roll bar, the scissors arms are extended while elevating the support bar whereby the canopy assumes a gabled roof-like configuration over the slide out unit. When the slide out unit is retracted, the support bar is lowered and folded into adjacent relationship with the scissors arms and adjacent to the side of the vehicle. 
   Other aspects, features and details of the present invention can be more completely understood by reference to the following detailed description of a preferred embodiment, taken in conjunction with the drawings and from the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric of a recreational vehicle having a slide out unit with the awning cover of the present invention mounted thereon and with the slide out unit in a retracted position. 
       FIG. 2  is an isometric similar to  FIG. 1  with the slide out unit in an extended position. 
       FIG. 3  is a rear elevation of the vehicle of  FIG. 1 . 
       FIG. 4  is a rear elevation of the vehicle as shown in  FIG. 2 . 
       FIG. 5  is a fragmentary isometric looking downwardly on the awning cover of the present invention in an extended position. 
       FIG. 6  is a fragmentary isometric similar to  FIG. 5  with the canopy being shown in dashed lines. 
       FIG. 7  is a fragmentary side elevation of the awning cover of the present invention mounted on the slide out unit as seen in  FIG. 5 . 
       FIG. 8  is a fragmentary side elevation of the awning cover in a retracted position adjacent to the side of the vehicle. 
       FIG. 9  is a fragmentary isometric with parts removed looking at the juncture of scissors arms with the support bar in the awning cover of the present invention with the scissors arms in an extended position. 
       FIG. 10  is a fragmentary isometric similar to  FIG. 9  with the scissors arms in a retracted position. 
       FIG. 11  is a top plan view of the awning cover of the present invention mounted on the slide out unit with portions of the canopy removed for clarity and with the awning cover in a fully-extended position. 
       FIG. 12  is a top plan view similar to  FIG. 11  with the awning cover partially retracted. 
       FIG. 13  is a top plan view similar to  FIGS. 11 and 12  with the awning cover fully retracted. 
       FIG. 14  is a fragmentary front elevation with parts removed of the support bar and its connection to the scissors arms with the awning cover in an extended position. 
       FIG. 15  is an enlarged fragmentary section taken along line  15 — 15  of  FIG. 14 . 
       FIG. 16  is an enlarged fragmentary section taken along line  16 — 16  of  FIG. 14 . 
       FIG. 17  is an enlarged fragmentary section taken along line  17 — 17  of  FIG. 11 . 
       FIG. 18  is a side elevation of a bracket used to connect the scissors arms to the center support rail. 
       FIG. 19  is an isometric of the bracket of  FIG. 18 . 
       FIG. 20  is a side elevation of a bracket used to connect a scissors arm to either the anchor rail or the roll bar. 
       FIG. 21  is an isometric of the bracket of  FIG. 20 . 
       FIG. 22  is an isometric of a scissors arm. 
       FIG. 23A  is an isometric of a connector used at the left end of the scissors arm as seen in  FIG. 22 . 
       FIG. 23B  is a side elevation of the connector shown in  FIG. 23A . 
       FIG. 24A  is an isometric of a connector used at the right end of a scissors arm as shown in  FIG. 22 . 
       FIG. 24B  is a side elevation of the connector of  FIG. 24A . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A recreational vehicle  30  is illustrated in  FIGS. 1 and 2  having a slide out unit  32  incorporated therein with the slide out unit being retracted into the unit in  FIG. 1  and extended away from the side of the unit in  FIG. 2 . It is to be understood that slide out units are found in other environments such as mobile homes, travel trailers and the like, and accordingly the teachings of the present invention are applicable to those environments as well. 
   The awning cover  34  of the present invention can be generally seen in  FIGS. 1 through 4  to comprise a gabled cover for the slide out unit  32  with the awning cover being correspondingly extendable with the slide out unit to assume the position of  FIGS. 2 and 4  and correspondingly retracted with the slide out unit to assume the position of  FIGS. 1 and 3 . Before describing the awning cover in detail, it should be appreciated that the slide out unit has an outer wall  36 , a pair of side walls  38 , a bottom wall (not seen) and a top wall  40 . The slide out unit may have windows  42  or the like in the outer wall as an optional feature of the slide out unit. The slide out unit is motorized in a conventional manner to move between the retracted position of  FIGS. 1 and 3  and the extended position of  FIGS. 2 and 4 . 
   The awning cover  34  of is probably best seen in  FIGS. 5 and 6  to include an anchor rail  44  mounted horizontally on the side wall  46  of the recreational vehicle, mobile home, travel trailer or the like adjacent the top of the side wall, a roll bar  48  extending parallel to the anchor rail and a flexible canopy  50  of generally rectangular configuration having an inner edge secured to the anchor rail  44  and an outer edge to the roll bar  48 . The roll bar is rotatably mounted on brackets  52  adjacent to the top edge of the outer wall  36  of the slide out unit with the roll bar being of conventional construction and spring biased so as to encourage the canopy to wrap therearound as the slide out unit is moved from the extended position of  FIG. 2  to the retracted position of  FIG. 1 . Of course, when the slide out unit  32  is extended along with the awning cover  34 , the canopy  50  unrolls from the roll bar against the spring bias of the roll bar. It should also be appreciated that the roll bar could be mounted on the side of the vehicle as opposed to the outer wall of the slide out unit with the anchor rail being on the outer wall of the slide out unit. It is only important that one edge of the canopy be anchored and the other edge be secured to a roll bar so that the canopy can be wrapped around the roll bar during retraction of the slide out unit. 
   The canopy  50  is supported from underneath by a scissors-type support system incorporating two identical pairs of scissor arms  54 . Each pair of scissor arms has a shorter inner support arm  56  and a longer outer support arm  58  even though the length of the support arms is not critical to the invention. The inner end  60  of each outer support arm  58  and the outer end  62  of each inner support arm  56  is connected to a roller bracket  64  that is supported and rollably mounted on an elongated support bar  66  having tracts  68  on opposite sides thereof. Movement of the awning cover  34  from a retracted position of  FIG. 13 , for example, to an extended position of  FIG. 11  causes the roller brackets to roll along the length of the support bar toward opposite longitudinal ends thereof. Obviously a retraction of the awning cover from the position of  FIG. 11  to the fully-retracted position of  FIG. 13  causes the roller brackets to roll toward a midpoint of the support bar and toward each other as the scissors arms  54  are folding inwardly toward a parallel and adjacent relationship with the support bar  66 . The inner ends  70  of the inner support arms  56  and the outer ends  72  of the outer support arms  58  are pivotably connected to mounting brackets  74  with the mounting brackets for the inner support arms being mounted on the side wall  46  of the recreational vehicle immediately beneath the anchor rail  44  and the mounting brackets for the outer support arms being mounted on an inner face of the roll bar  48 . The pivotal mounting of each end of a support arm  56  or  58  to either the roller bracket  64  or a mounting bracket  74  permits folding and unfolding movement of the scissors arms as the slide out unit and awning cover move simultaneously between the extended and retracted positions. 
   With reference to  FIGS. 14 through 16 , it will be appreciated that the support bar  66  is of generally I-beam construction having a gabled top surface  76  and as mentioned previously tracts  68  defined in each longitudinal side. The tracts confine roller wheels  78  mounted on the roller brackets  64  seen best in  FIGS. 18 and 19  to allow the roller brackets to move longitudinally along the length of the support bar. 
   Each roller bracket  64  is of generally channel-shaped configuration, having a bottom wall  80  and a pair of upstanding side walls  82  with the side walls having aligned passages  84  therethrough which serve as bearings for the axles  86  of the roller wheels  78  positioned in the channel of the roller bracket. In a preferred embodiment, there are two roller wheels associated with each side wall of each roller bracket with a pair of roller wheels being disposed for engagement with the track on one side of the support bar and a pair of roller wheels with the track on the opposite side of the support bar. The wheels on opposite sides are longitudinally offset from each other. At one end of the roller bracket  64 , bifurcated supports  88  having fingers  89  are established for receiving pivot pins  90  ( FIG. 11 ) associated with the ends of the inner and outer support arms  56  and  58  associated with that roller bracket. It will be appreciated that while the bifurcated supports  88  are of course separated from each other to each receive one end of a support arm  56  or  58  as will be described later, each finger has an opening  91  therein which will be described later to pivotally receive a pivot pin  90  so that the pivot pin lies in a vertical plane but at an acute angle to vertical, such as approximately 30°. 
   The mounting or anchor brackets  74  for pivotally mounting the opposite ends of each of the support arms  56  and  58  are identical and shown in FIGS.  20  and  21 . It will there be seen that each anchor bracket has a box-like main body  92  with bifurcated spaced fingers  94  protruding from one end of the main body. Passages  96  are provided through the main body so that the anchor brackets can be secured to either the side wall  46  of the vehicle or the outer wall  36  of the slide out unit. The bifurcated fingers  94  are again spaced from each other to pivotally receive an end of a support arm  56  or  58  with each arm having opposed openings  98  to receive a pivot pin  90  for the end of the associated support arm. The pivot pins while lying in a vertical plane are inclined relative to vertical at an acute angle of approximately 30°. As will be appreciated, the angle of inclination of the pivot pins on the roller brackets  64  and those on the anchor or mounting brackets  74  are in opposite directions relative to vertical. The angled orientation of the pivot pins perform a function to be made more clear later in lifting the support bar  66  as the awning cover is extended and lowering the support bar when the awning cover is retracted. 
   With particular reference to  FIGS. 14 through 16 , and particularly  FIGS. 14 and 15 , the roller brackets  64  can be seen supporting a pair of roller wheels  78  from each of its upstanding side walls  82 . The roller wheels on the opposite sides of the roller bracket as mentioned previously are offset longitudinally from each other but in combination allow the roller bracket to roll easily along the length of the support bar  66  within the tracks  68 . Three clips  100  as seen in  FIGS. 14 and 16  are positioned along the length of the support bar with one clip being at the approximate longitudinal midpoint of the support bar and the other two clips being equally spaced therefrom in opposite directions. Each clip is positively positioned in the tracks along opposite sides of the support bar by a rivet  102  with each clip having a component disposed in each track of the support bar. The clips are present in each track to engage the roller wheels in a roller bracket and thereby limit the movement of the roller brackets along the length of the support arm. 
   As will be appreciated by the above, the support bar  66  is supported only by the roller brackets  64  and the associated scissors support arms  56  and  58 , and of course the roller brackets move along the length of the support bar. The clips  100  are provided to make sure that the support bar is centered when the awning cover is fully retracted or fully extended. Accordingly, the clips are positioned as mentioned previously with one clip at the longitudinal midpoint of the support bar so as to be engaged on opposite sides by the roller brackets when the awning cover is fully retracted. When the awning is fully extended, the roller brackets are adapted to engage the remaining two clips which as mentioned previously are spaced equidistantly from the centered clip. The clips are positioned so that the roller brackets engage the clips at either the fully extended or fully retracted position of the awning cover. 
   With reference to  FIG. 22 , a scissors support arm  56  is illustrated as comprising a hollow body  104  of rectangular transverse cross section having connectors  106  positively connected in the opposite ends thereof. The connectors are of identical construction but mounted in the ends of the scissors arm in opposite orientations. The connector can be seen in any one of  FIG. 23A ,  23 B,  24 A or  24 B as including an insert  108  adapted to be received and anchored in the associated open end of the support arm and a protruding body  110  with the protruding body having a rounded, partially cylindrical extension  112 , with a passage  114  therethrough for receipt of a pivot pin  90 . The passage  114  through the extension is adapted to remain in a vertical plane during operation of the awning cover  34  but is inclined relative to vertical at an acute angle of for example 30°. The extension  112  at the left end of the scissors arm is shown inclined downwardly and to the left so that the passage  114  therethrough is inclined upwardly and to the left while the connector  106  at the opposite or right end of the scissors arm has its extension  112  sloped upwardly to the right so that the passage  114  therethrough is sloped upwardly and to the left parallel with that of the passage in the connector at the left end of the support arm. Each support arm  56  or  58  is identical except in its length with the two outer support arms  58  being of the same length and the two inner support arms  56  being of the same length even though all four support arms could be of the same length if desired. The left end of the support arm illustrated in  FIG. 22  is mountable to the roller bracket  64  while the right end is mountable to an anchor bracket  74 . The connectors  106  are mounted to the roller bracket or the anchor bracket with pivot pins  90  as mentioned previously in a conventional manner so that each end of a support arm is adapted to pivot relative to its associated roller bracket or anchor bracket. 
   As is probably best appreciated by reference to  FIGS. 9 ,  10  and  17 , due to the angulated mounting of the pivot pins  90  connecting the support arms  56  and  58  to the roller brackets  64  and the anchor brackets  74 , the support arms are alignable with the roller brackets and anchor brackets as well as the anchor rail  44  or roll bar  48  when the awning cover is fully retracted as best seen in  FIG. 10 . This of course is the position of one pair of support arms and the associated roller bracket when the awning cover is fully retracted. When the awning is extended, however, as shown in  FIGS. 9 and 17 , due to the angle of the pivot pins  90  at each end of a support arm, the end of the support arm connected to the roller bracket is elevated relative to its opposite end, thereby positioning the support bar  66  and of course the flexible canopy  50  overlying the support bar at an elevated position. As the awning cover is extended and the support bar is lifted, as mentioned previously, the roller brackets roll along the support bar from the substantially centered position of  FIG. 13  through an intermediate position of  FIG. 12  to an outermost position of  FIG. 11  where they engage the outer two clips. 
   Raising the support bar  66  as the awning cover  34  is extended creates a gabled configuration for the awning canopy  50  in the fully extended position, so that rain, debris and the like are encouraged to run off the canopy rather than accumulate on the canopy as in prior art arrangements. A gutter (not shown) may be provided along the side wall of the vehicle to transfer any water that runs off toward the side wall  46  of the vehicle to be directed to one side or the other of the slide out unit  32 . 
   Although the present invention has been described with a certain degree of particularity, it is understood the disclosure has been made by way of example, and changes in detail or structure may be made without departing from the spirit of the invention, as defined in the appended claims.

Summary:
A retractable awning cover for a slide out unit on a recreational vehicle, mobile home, travel trailer or the like includes a scissors arm support system that elevates a support bar running longitudinally of the vehicle to establish a gable shape for the awning cover when extended. The support bar is automatically lowered during retraction so as to be alignable with the scissors arms that support the support bar.