US 3850470 A
An expandable housing unit which has an upper housing section mounted for telescopic extension and retraction over a lower housing section, and drawers which are mounted in each side of the lower housing section for lateral movement between the extended and retracted positions when the upper housing member is raised. The drawers are fitted with vertically moveable roof sections which are normally in a retracted position when the upper housing member is in the lowered position and which are spring-urged upwardly so as to follow the upper housing member as the latter is raised.
Claims available in
Description (OCR text may contain errors)
United States Patent [1 1 Trelle Nov. 26, 1974 EXPANDABLE HOUSING UNIT Primary Examiner-Robert B. Reeves r. 0 a Trelle, 8175-19 Ave.,  Invemo fi i g British Columbia, Canada Asszstant Exammer-l-l. Grant Skaggs, Jr.
Attorney, Agent, or Fzrm-Carver and Company  Filed: Aug. 13, 1973 [21 App]. No.2 387,917
57 ABSTRACT Cl 296/23 96/23 MC, 296/27. An expandable housing unit which has an upper hous- /6 ing section mounted for telescopic extension and re-  [Ill- CI. A47f13/06 traction over a lower hgusing section, and drawers Field f 296/26, 23 R, 23 C, 23 MC, which are mounted in each side of the lower housing 67 section for lateral movement between the extended and retracted positions when the upper housing mem- References Cited ber is raised. The drawers are fitted with vertically UNITED STATES PATENTS moveab le roof sections which are normally in a rel,972,4l5 9/1934 Anderson 296/26 acted Position when the PPer housing mmber is in 2.756.094 7/1956 Marple 296/23 c the lowered Position and which are Spring-urged P- 3,208,111 9/]965 Grossman 49/425 Wardly 50 as to follow the upper housing member as 3.304.670 2/l967 Logan 296/23 R the latter is raised.
FOREIGN PATENTS OR APPLICATIONS 7 Claims, 12 Drawlng Figures 835.844 4/l952 Germany 296/23 C SHEET 1 BF 9 IIIII U I w l T I IHH I I PATENTL; x312 61974 saw 2 OF 9 Qm $3 NS WEEK 7 W 9 FOR WARD PATENT}; KEV 2 6 I974 SHEU 8 BF 9 Ill-"Illll'l'l l lllllllllllllll 3.850.470- SHEU 8 [IF PATENTEmvzsmm EXPANDABLE HOUSING UNIT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to expandable housing units and in particular, but not limited, to housing units which are carried in the box of a truck the combined unit being normallly termed a camper.
2. Prior Art In transportable housing units of the house trailer and camper types, particularly the latter type, provision of adequate fioor space and head room is a major concern. The shift of the effective center of gravity due to wind resistance, side and front, dictates to a large measure, the overall dimensions of the housing unit.
In order to minimize wind resistance when the unit is being operated on the road and yet to provide adequate habitable space when the unit is used for accommodation, a number of configurations have been devised whereby the housing unit can be contracted for travel and expanded when used for accommodation.
In one type of configuration, the housing unit has an upper roof section which fits over a lower section for telescopic movement between raised and lowered positions so as to provide adequate head room when the unit is used for accommodation and also provides a minimal frontal and side area to minimize wind resis tance when travelling. This type of unit also includes drawers in which beds and like pieces are built, which can be moved outwards from a contracted position within the body of the unit to an extended position so that substantially the entire floor of the unit is clear when the unit is set up for accommodation.
In previous drawer type units, drawers are provided with roofs which may be canvas or wood and which usually have a connection, hinged or otherwise to the upper edge of the drawer. The roof elevation is therefore limited by the height of the drawer which is normally below eye level when the camper is expanded. Consequently head room within the drawers is insufficient and can engender a claustrophobic effect.
Drawer type units of prior art often prove difficult to arrange in the expanded and contracted conditions, particularly in respect of moving the drawers between the extended and retracted positions. Also considerable time is required to erect and fasten drawer roofs and effect proper seals between relatively secureable parts to ensure that the unit is sustantially proof against the elements.
SUMMARY OF THE INVENTION The present invention provides a portable housing unit particularly adapted to, but not restricted to, use as a camper which is of the expanding andcontracting drawer type, which can be disposed easily in the expanded condition, and is substantially weatherproof when expanded. The unit is constructed to provide sufficient head room within the unit, and drawers themselves, so necessary for comfortable living.
The portable housing unit of the present invention has a lower housing section, an upper housing section mounted over the lower section for telescopic movement between the raised and lowered positions, confronting openings in adjacent side walls, a drawer mounted for movement between a retracted position within the lower section and an expanded condition extending laterally therefrom, and a roof on the drawer normally disposed beneath the upper section when the latter is in its lower position and clear of the side wall edges of the upper section when the latter is in the raised position.
In one embodiment of the invention the drawer roof is mounted for vertical movement on the drawer so that the roof can be raised and lowered when the upper housing section of the unit is raised and lowered.
In another embodiment of the invention the roof of the drawer is fixed relative to the drawer.
In the description following, the drawings merely show and the detailed description merely describes preferred embodiments of the invention which, however, is capable of expression in structure other than that particularly described and illustrated.
DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a camper unit including a truck, and one embodiment of a housing unit of the invention in a contracted condition,
FIG. 2 is a perspective view of the housing unit in an expanded condition,
FIG. 3 illustrates, diagrammatically, mechanism for raising and lowering the upper housing section of the unit,
FIG. 4 is a transverse sectional view of the housing unit in a contracted condition,
FIG. 5 is a view similar to FIG. 4 of the housing unit in an expanded condition,
FIG. 6 is a longitudinal sectional view of support mechanism for enabling movement of a drawer,
FIG. 7 is a section taken on line 77 of FIG. 6,
FIGS. 8, 9, and 10 are sections taken on lines 8-8,
99 and l0-10, respectively, of FIG. 2 illustrating sealing arrangements,
FIGS. 11 and I2 are views similar to FIGS. 4 and 5 of another embodiment of the invention.
DETAILED DESCRIPTION Referring to the drawings, and in particular to FIG.
- 1, one embodiment 10 of a transportable expandable housing unit of the invention is shown mounted on a pickup truck 11 which can, obviously, be any type of truck or conveying vehicle. The truck, conventionally, has a substantially rectangular box 12 having side panels I3l3 and a hinged tailgate 14. v
The housing unit 10, refer to FIGS. I and 2, has a roofless lower housing section 15 having a lower portion 16 which fits the truck box space being provided for fender clearance, see FIGS. 4 and 5, and a rectangular upper portion 17 which is the same length as the lower portion but is wider than the latter so as to extend over the side panels of the truck box. Left and right side walls 21 and 22, of the housing section 15 terminate at the juncture of the portion 16 and 17. Front and rear end walls 23 and 24 ofthe lower housing section 15 are of equal height and thus bound left and right openings 25 and 26, see FIG. 3, into the upper portion 17.
A roofed upper housing section 27 is mounted over the lower housing section for telescopic movement between a lowered position, as seen in FIG. 1, and a raised position, as seen in FIG. 2. Left and right side walls 31 and 32 and front and rear end walls 33 and 34 are of the same depth.
Movement of the upper housing section between its raised and lowered positions is effected by operation of the worm type winch 36, see FIG. 3, which is located in the right hand space between the right side of the lower portion of the lower housing section and the right side panel of the box and it is operated by a crank, not shown, which fits into a socketed end 37 of the worm which projects through a rear false wall of the lower portion of the lower housing section. The winch has a drum 38 on which a pair of cables 41 and 42 are wound. The cable 41 is connected to a pair of cables 43 and 44 which extend over pullies. severally 46, secured to the rear end wall upper portion of the lower housing section and are secured to the lower edges of the upper housing section side walls. The cable 42 passes over a pulley 46.1 mounted on the front wall of the lower portion of the lower housing section and is connected to a pair of cables 47 and 48 which pass over pulleys, severally 49, mounted on the upper portion of the front end wall of the lower housing section adjacent the upper edge thereof and are secured to the side walls near the lower edges thereof. The arrangement so illustrated and described results in centering of the upper housing section on the lower housing section during movement so that special guides are not required and. further, as the drive is through the worm type winch, the upper housing section is automatically locked in its raised position but can be lowered by reverse operation of the winch.
The left and right side walls 31 and 32 of the upper housing section are provided with openings 53 and 54, respectively, which are substantially the same length as the openings and 26 and which open out of the lower edge of said upper housing section side walls but terminate short of the roof of the upper section so as to provide upper side wall portions 55 and 56, respectively and, lower side wall portions, severally 57.
Left and right drawers 61 and 62, respectively, are mounted in the openings of the lower housing section for movement through the openings in the lower and upper housing sections between retracted positions, as shown in FIGS. 1 and 4, and expanded positions, as shown in FIGS. 2 and 5. The drawers are disproportionate in width. The right hand drawer 62 is designed to carry a bunk or bed and the left hand drawer 61 is designed to carry kitchen equipment and the like which, in total, are heavier than a bed and the like so that the combined center of gravity of the drawers and equipment they carry when the drawers are placed in the extended or retracted conditions. is substantially centerecl over the center line of the unit.
The left drawer 61 has a body portion, generally 63, which has front and rear end walls 65-65, a bottom wall 66, a lower side wall portion 67, and an upper side wall portion 68 which is inset relative to the lower side wall portion 67. A roof section generally 69 has a roof 7], end walls 7272, and an outer side wall 73, and telescopically fits over the upper portion of the drawer 61 against the upper side wall portion 68 thereof for movement between an elevated position, as shown in FIGS. 2 and 5, and a lowered position, as shown in FIGS. 1 and 4. Dimensions of the housing unit thus far described are so related that in the contracted condition the roof section 69 of the drawer fits beneath the upper housing section, inside the upper side wall portion 55 thereof, with said upper side wall portion and the lower side wall portion 67 of the drawer flush with each other. In the expanded condition, as shown in FIGS. 2 and 5, the upper housing section of the unit is raised sufficiently to enable the raised roof section of the drawer to clear the lower edge of the side wall at the opening 53 to permit the drawer and roof section to be disposed in the extended position.
The drawer 61 is supported at each end by support assemblies, generally 75, which can be disposed, selectively, to provide rolling support for the drawer so the latter can be moved easily between its retracted and extended positions or to provide frictional resistance to movement of the drawer so that the latter is frictionally restrained from movement from either of said positions.
A support assembly, shown partially in FIG. 2, outlined in FIGS. 4 and 5 and in detail in FIGS. 6 and 7, includes a U-section rail which has an inboard portion 77, see FIG. 6, secured inside the upper portion of the lower housing section, not shown in FIG. 6, against an adjacent end wall, the outer end 78 of the said inboard portion terminating short of the adjacent lower side wall portion 57 of the upper housing section when the latter is fully lowered. An outboard rail portion 79 is hingeably connected at the outer end of the inboard portion on a hinge bolt 81 for movement between a stowed vertically upstanding position FIG. 4 and an extended position, FIG. 2 and 5, in which it swings outwardly to a position co-extensive with the inboard portion. As shown in FIGS. 6 and 7 an elongated U-shaped brace piece 82 is mounted on the bolt 81 inside the outboard rail portion and is welded thereto as at 83 for swinging movement therewith. The brace piece it is seen provides additional support for fore and aft alignment of the inboard and outboard portions of the rail and prevents the outboard portion from swinging downwards past the co-extensive position. In the coextensive position the inboard and outboard portions of the rail present upper bearing surfaces which lie in a common plane. A cable 85, see FIG. 2, connected between the lower housing unit and other end of the outboard portion of the rail provides additional support for said portion.
The drawer is supported on the rail by an elongated box-sectioned support member 91, FIG. 6, which is bolted to an outer surface of an end wall ofthe drawer,
immediately above the rail and has a flat under wall 92 which rests on and frictionally engages the upper surface of the rail.
An extendable and retractable roller assembly, generally 95, is mounted in the support member operable, selectively, to provide either frictional or rolling support of the drawer on the rail. The roller assembly includes rollers, severally 96, which are mounted on axles 97 carried on lower end of yokes severally 98. The yokes are mounted for a pivotal movement, near their midlength, on pins 101 which extend transversely through the support member. The upper ends of the yokes have pivotal connections severally 102 with a push/pull rod 103 which extends longitudinally through the support member. A lever 105 is mounted for pivotal movement on a pin 106 at an outer end of the support member and also has a pivotal connection at, 108, with the push/pull rod so that movement of the lever effects longitudinal movement of the push/pull rod and swings the roller yokes about the pins 101. The parts are so arranged that with the lever in an upright position, as shown in solid outline, the rollers take a retracted position as shown in solid outline. When the lever is swung downwards to a position as shown in broken outline the movement of the push/pull rod swings the rollers through an over-center position in which they project through openings severally 110, in the under wall 92 of the support member so as to engage the rail and lift the support member off the latter. Engagement of the lever with a stop 110.1 which can be a pin extending through the support member limits rotation of the yokes about their pivot pins 101 to the over center position so that the rollers are effectively releaseably locked in extended positions and can only be returned to retracted positions by reverse operation of the lever. A coil spring 111 mounted on the pivotal connection 108 bears against the push rod and lever and normally urges the lever to an upward extending position so as to maintain the rollers in the retracted positions.
lnner and outer spaced stops 112 and 112.1 are secured to the support member for engaging a bracket 113 mounted on the adjacent end wall, not shown in FIG. 6, of the lower housing section to limit movement of the drawer between its extended and retracted positions and to limit vertical movement of the drawer. A spring connecting bracket 114 is also mounted on the inner end of the support member. A similarrail, support member and roller assembly provides support for the opposite end of the drawer.
Referring to FIGS. 4 and 5, the roof section 69 ofthe drawer 61 is automatically raised to its extended position, when the upper housing section is raised to its extended position, by a spring operated hoist assembly, generally 115 located at each end of the drawer. Each hoist assembly has a normally tensioned coil spring 115.1 which is connected at one end to the bracket 114 1 ofthe adjacent support member 91 and is connected at its other end, substantially at the midpoint of a lever 116 which is pivotally mounted at one end 116.1 on a pivot pin 118 projecting from the adjacent end wall 65 ofthe drawer 61. A pair of cables 119 and 121 are connected to the other end of the lever 116 and pass upwards over pulleys, severally 121.1, mounted adjacent the upper edge of the end wall of the drawer 61 and are connected to the drawer roof section adjacent the lower edge of end wall 72 thereofan opposite sides of the center of gravity of the roof section 69. It is seen that when the roof section is lowered the cables are drawn over their respective pulleys thus rotating the lever 116 upwards around its pivot pin 118 thus extending the spring and increasing its tension. When the upper housing section 27 is raised the lever swings downwards under the action of the spring thus lifting the roof section of the drawer so that it follows the upper housing section as the latter is raised.
In order to maintain a near even tension on the cables 119 and 121 as the roof section moves between its raised and lowered positions the lever 116 is disposed so that as it rotates upwards the roof section of the drawer descends under the weight ofthe lowered upper housing section 27, the angle between the lever axis and the cables 119 and 121 increases from an acute angle to substantially a right angle. Thus, as tension of the spring increases, lever advantage of the spring on the cables decreases. Relationship of spring extension and angular change is so determined that tension on the cables throughout full movement of the roof section of the drawer between its raised and lowered positions remains substantially constant.
The roof section 69 is guided for vertical movement by a vertical guide piece 122, FIGS. 2 and 5, secured to the front and rear walls, 65 of the drawer and fits in a way, not shown, in the drawer roof section. Upward movement of the drawer roof section is limited by engagement of stops, severally 123, secured to lower edges near the corners of the drawer roof section and upper edges near the corners of the drawer body portion.
To effect sealing of the housing unit in either its expanded or contracted condition, against wind and weather, novel sealing arrangements are employed. FIG. 8 shows a typical sealing arrangement for sealing an end wall 65 of a drawer and the forward wall 23 of the lower housing section. The end wall of the drawer has vertically disposesd laterally extending flange 125 positioned near the inner edge of the drawer end wall which engages, when the drawer is moved to its fully extended position, bristles of a brush 126 which extends vertically along the inside face of the wall 23 adjacent. A flexible flap 127 is secured to the end wall 23 outboard of the brush 126 against which the flange 125 bears when the drawer is moved to the extended position. This combination results in a virtually weatherproof seal.
As shown in FIG. 9 the brush 126 and flap 127 serve to provide a seal between the end wall 23 and the outboard hinged portion 79 of the rail 77 when the latter is swung to the stowed position.
As shown in FIG. 10 a brush seal arrangement is, effectively, employed for effecting sealing engagement between the upper and lower housing sections when the upper section is in its raised position. As shown a brush 130 is secured inside the forward end wall 33 of the upper housing section along and adjacent the lower edge thereof and a brush 131 is secured to the adjacent end wall of the lower housing section on the outer surface thereof extending along the upper edge. The brushes 130 and 131 move into engagement with each other when the upper housing section is fully raised. A similar sealing arrangement, provides sealing engagement between the adjacent rear walls of the upper and lower housing section and between three sides of the drawer roof section 69 and the drawer body portion 65.
Referring to FIGS. 4 and 5, sealing between the roof section 69 of the drawer and the upper housing section 27 is provided by means of an external flange 134 which extends outwards of the inner edges of the drawer roof and end walls and which carries a resilient non-wicking sealing element 135 which engages the inside surface of the upper housing section adjacent the opening therein. Brush seals, severally 136, are used to provide sealing engagement between the drawer bottom and the side wall of the lower housing section.
The right hand drawer 62 has a roof section 137 similar to the roof section of the drawer 61 which is operated by a spring urged hoist 138 which operates in a manner as described with reference to the spring urged hoist associated with the left hand drawer 61. Furthermore sealing arrangements of the drawer 62 is similar to that described with reference to the drawer 61.
The drawer 61 and likewise the drawer 62, see F IG. 2, are provided with inspection and service panels severally 139 and the side walls of the roof sections on section when the unit is contracted and the worm socket 37 of the winch is covered by the tailgate of the truck so that with the tailgate locked unauthorized entrance into the housing unit is effectively prohibited.
OPERATION The housing unit, mentioned is disposed in a contracted position for travelling so as to minimize wind resistance. To set up the unit for habitation the end gate of the truck is lowered and the upper section of the unit is raised by operation of the winch the roof sec tions of both drawers automatically move to the fully extended position as the upper housing section is raised. The hinged outboard portion of the rails at each end of the drawers are then swung outward to their horizontal positions and the operating levers of the roller assemblies are then operated to extend the rollers. The drawers are then pulled out to their extended position and the rollers then returned to their retracted position to lower the supporting members of the drawers onto their respective rails. The housing unit is thus ready for occupancy.
To return the unit to its contracted position the drawer rollers are moved to their extended positions and the drawers moved inwards to their retracted position and the rollers then returned to their retracted positions so that the drawer is frictionally secured against movement. The hinged outboard portions of the rails are then swung upwards to their stowed positions against the outer end of each of the drawer supporting members and the upper housing section is lowered. The lower side portions of the side walls of the upper housing section extend over the outboard hinged portions of the rails so that said portions cannot again swing outwardly. The drawers are, therefore, held captive in their retracted positions.
ALTERNATE EMBODIMENT FIGS. 11 and 12 show another embodiment 150 ofa housing unit in accordance with the invention which is shown in an expanded condition in FIG. 12 and in a contracted position in FIG. 11.
The housing unit 150 has an upper housing section 151 and a lower housing section 152 which are substantially similar to the upper and lower sections of housing unit 10, the upper housing section 151 being raised and lowered by a cable and winch arrangement, not shown, which is the same as that described with reference to the unit 10.
Left and right drawers I53 and 154, are mounted in the lower housing section 152 in the same manner as are the left and right drawers of unit for movement between retracted positions shown in FIG. 11 and extended positions as shown in FIG. 12. Support assemblies, generally 156, which are the same as the support assemblies 75 of unit 10 are employed to facilitate movement of the drawers 153 and 154 between extended and retracted positions.
Left and right side walls 157 and 158, of the upper housing section 151 do not have openings in the same manner as the left and right side walls as described with reference to the upper housing section of unit 10 but extend unbroken from top to bottom.
The drawers 153 and 154 have fixed roofs 161 and 162, respectively, which, when the upper housing section 151 is fully raised, the roof just clears the lower edges of the side walls so that the drawers can be moved between extended and retracted positions. Inner edges of the roof sections 161 and 162 are provided with upstanding flanges 163 and 164 which make sealing engagement with the side walls when the drawers are fully extended. Sealing arrangements as described with reference to the unit 10 are employed in the unit where required.
The unit 150, it is seen, when contracted provides minimal frontal and side area yet when expanded provides head room beneath the upper housing section which is substantially the same as that provided by the unit 10. Head room beneath the roofs of the drawers is however somewhat reduced substantially by the extent of vertical movement of the roof sections of the drawers of unit 10.
Manufacturing costs, however, of the unit 150 are correspondingly less than the costs of the unit 10 as the fixed roof section obviates the necessity of providing a hoist assembly and consequently eliminate much of the sealing arrangements found in the unit 10. The weight of the unit 150 is correspondingly less than the weight of unit 10 and is more adaptable to smaller conveying units.
1. An expandable housing unit including:
a. a roofless lower housing section having four walls and a floor,
b. a roofed upper housing section having four walls mounted over the lower housing section for telescopic movement a raised position and a lowered position,
c. means for moving the upper housing section between said positions,
d. an opening in at least one wall ofthe lower housing section extending substantially from end to end thereof,
e. a drawer having end walls mounted in the opening,
f. a roof section over the drawer lying below and clear of the lower edge of an adjacent wall of the upper housing section when the latter is fully raised,
g. means for mounting the drawer for movement between a retracted position within the lower housing section and an extended position projecting outward therefrom with said means including:
i. a rail having an inboard portion secured to an end wall of the lower housing section,
ii. and having an outboard portion hingedly connected to the inboard portion for swinging movement between a substantially vertically upstanding position co-extensive with the inboard portion,
iii. an elongated support member secured to an adjacent end wall of the drawer for engaging the rail and supporting the drawer thereon.
iv. a plurality of rollers mounted on the support member for movement between the retracted positions above the support member and extended positions extending below the support member for engagement with the rail so as to provide rolling support for the drawer on the rail and,
v. manually operative means for moving the rollers between said positions.
2. An expandable housing unit as claimed in claim 1 in which the means for moving the rollers between extended and retracted positions include:
a. a yoke for each roller pivotally mounted substantially intermediately between its ends having an axle at a lower end on which each roller is mounted,
b. an operating rod having a pivotal connection at the upper end of each of the yokes,
c. a lever hingeably mounted at outer end of the support member and having a pivotal connection with the operating rod for pivoting the yokes so as to move the rollers between the extended and retracted positions.
3. An expandable housing unit as claimed in claim 2 in which the yokes move through an over center position when the rollers are moved between their extended and retracted positions and including stop means for limiting the movement of the yokes when the rollers reach the extended positions so as to releaseably lock the rollers in said extended positions.
4. An expandable housing unit including:
a. a roofless lower housing section having four walls and a floor,
b. a roofed upper housing section having four walls mounted over the lower housing section for telescopic movement between a raised position and a lowered position,
c. means for moving the upper housing section between said positions,
d. an opening in at least one wall of the lower housing section extending substantially from end to end thereof,
e. a drawer having end walls mounted in the opening,
f. a roof section over the drawer mounted for telescopic movement between raised and lower positions and.
g. resilient means operable independently of position of the drawer relative to the upper housing section for yieldably urging the roof section of the drawer 0 upwards against the upper housing section so that said roof section automatically follows said upper housing section as the latter is moved between its raised and lowered positions,
h. means for mounting the drawer for movement between a retracted position within the lower housing section and an extended position projecting outward therefrom.
5. An expandable housing unit as claimed in claim 4 in which means for raising and lowering the roof section of the drawer include:
a. pulley means mounted adjacent the upper edge of an end wall of the drawer,
b. a cable means passing over the pulley means and connected to the lower edge of an end wall of the roof section,
c. a preloaded spring urged mechanism connected to the cable means for moving the roof section of the drawer to its raised position when the upper housing section is raised and yieldably permitting return of the roof section to its lowered position under the weight of the upper housing section when the latter descends to its lowered position.
6. An expandable housing unit as claimed in claim 5 in which the preloaded spring urged mechanism includes:
a. a lever mounted adjacent one end on an end wall of the drawer for swinging movement and connected at an opposite end to the cable means,
b. a preloaded spring connected at one end to the lever at substantially the midlength thereof for urging the lever to rotate in a direction to apply tension on the cable means.
7. An expandable housing unit as claimed in claim 6 in which the cables and lever are disposed so that the internal angle between the cables and lever increases from an acute angle to substantially a right angle as the drawer roof is moved from its raised position to its lowcred position so to reduce effective lever advantage on the spring so that the tension on the cables remains substantially the same throughout movement of the drawer roof between its raised and lowered positions.