AU651008B2 - A power lift arrangement for elevating a vehicle roof - Google Patents

Description

-1~ Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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Name of Applicant: THE AIRTIGHT GARAGE PTY LTD Actual Inventor: DAVID GEORGE BEADLE Address for Service: R K MADDERN ASSOCIATES, 345 King William Street, Adelaide, South Australia, Australia Invention title: "A POWER LIFT ARRANGEMENT FOR ELEVATING A VEHICLE ROOF" Details of Associated Provisional Application No: PK 8979 filed 18th October 1991 The following statement is a full description of this invention, including the best method of performing it known to us.

1 This invention relates to a power lift arrangement for elevating a roof section of a vehicle, and in particular to a lift arrangement for raising and lowering the "pop top" of a caravan.

"Pop top" caravans and campervans are well known in the industry and generally refer to a vehicle which has a portion of its roof which can be moved between raised and lowered positions, the roof portion when raised, providing additional accommodation space within the interior of the vehicle and assisting in the ventilation of the vehicle interior.

Existing "pop top" lifting mechanisms make use of two or more scissor mechanisms, at opposite sides of the "pop top" roof, the links of each scissor mechanism having ends guided for horizontal movement along upper and lower horizontal guide channels. This arrangement is generally not satisfactory in that the manual force which is required in order to initiate the lifting movement of the "pop top" roof is quite significant. Consequently, the raising and lowering of the "pop top" roof can be quite difficult especially for elderly people. This also applies to the lowering of the "pop top" roof from its raised position.

It is also known to use direct lift vertical air rams in order to raise and lower a "pop top" roof; however, the installation of the rams is rendered difficult due to the space limitations existing within a caravan interior and as well there is the problem of concealing the rams from view.

It is the main object of the present invention to provide an improved power lift mechanism suitable for lifting a "pop top" roof of a caravan or campervan, which is simple, relatively inexpensive and which can be operated without manual exertion.

It is a further object of the present invention to provide an improved power lift arrangement for "pop top" roofs which is 2 designed so that it can be readily and conveniently installed in existing caravans and hence need not necessarily be fitted as original equipment.

Broadly according to this invention therefore, an improved power lift mechanism for raising and lowering an extendible roof section of a roof of a caravan or campervan (hereinafter "the vehicle") comprises a scissor mechanism movably supporting said extendible roof section between raised and lowered positions, said scissor mechanism comprising a pair of opposed scissor linkages which include elongated links extending between and in movable engagement with a pair of upper channel tracks carried by the roof section adjacent opposite sides thereof and a pair of lower channel tracks located adjacent opposite sides of an opening in which the I extendible roof section is mounted, characterised by: a pair of power rams, one at each side of the extendible S roof section, each ram being approximately horizontal when the roof section is in its fully lowered position and having its piston rod end guided for movement along a respective said upper channel track and its cylinder end pivotally attached to a mount on the roof of the vehicle near to or adjacent an end thereof, and a connecting linkage between the piston rod end of each said ram and the upper end of a respective said link of a said scissor linkage, arranged so that during the initial extension of the rams the connecting linkages co-operate with respective engagement surfaces on the roof of the vehicle and by virtue of a cam action exert an upward lifting force sufficient to effect initial lift of the movable roof section away from its fully lowered position, whereafter it continues to be raised by the resultant upward lifting forces provided by the rams.

Preferably, the connecting linkage comprises first and second depending links, the upper end of said first link being pivotally connected to a respective said piston rod end, its lower end being pivotally connected at a point intermediate 3 i, the ends of said second link, said second link having its upper end pivotally connected to the end of a said scissor link in moveable engagement with a said upper channel track, its lower end carrying a ramp engaging member which is arranged to move upwardly along a ramp surface fixedly located adjacent a respective said lower channel track, when the ram is initially extended.

Preferably the ramp engaging member comprises a roller which is arranged to travel upwardly along a ramp which is fixed adjacent the side of the vehicle roof, approximately centrally thereof.

Preferably the first link of the connecting linkage is provided with an abutment member for limiting the extent of S relative pivotal movement between the first and second links.

S1$ Preferably the piston rod end of each ram and also the movable ends of the links of the scissor linkages comprise o 0 rollers which rollingly engage along corresponding channel tracks.

S, i The lift arrangement of this invention lends itself for 1ae installation in a confined space and, despite the small angle of inclination of the lifting rams when the movable roof section is in its lowered or retracted position, the lift mechanism is able to effect the initial lift of the movable roof section from its lowered position, whereafter the rams are inclined sufficiently to continue the lifting movement of the roof section, assisted by the scissor mechanism.

In order to more fully explain the present invention, an embodiment is described hereunder in some further detail with reference to and is illustrated in the accompanying drawings wherein: Fig. 1 is a side elevational view of the lift arrangement of this invention fitted to a "pop top" caravan, showing the "pop top" in its raised position; 4 Lm r -i Fig. 2 is a view similar to Fig. 1, showing the "pop top" in its lowered position; Fig. 3 is a fragmentary elevational view of the connecting linkage shown when the "pop top" is in its elevated position; Fig. 4 is a view similar to Fig. 3, showing the connecting linkage when the "pop top" is in its lowered position, whilst Fig. 5 is a fragmentary sectional view taken through the connecting linkage.

In this embodiment, the lift arrangement is described with reference to a "pop top" caravan of known type wiich comprises a "pop top" roof 11 movable between a collapsed transport position where it is contiguous with the roof 10 of the caravan and a raised or extended position where it is S I' vertically spaced above the caravan roof 10 so as to increase oeelJ the amount of interior space within the caravan.

ooretl o The "pop top" 11 has an upper horizontal wall 12 and a depending peripheral flange 13, and is movably supported at each of its opposite sides by means of a scissor linkage mechanism 14 between collapsed and elevated positions, each 'scissor mechanism 14 being operatively coupled via connecting linkages 15 to a pair of transversely aligned pneumatic rams 16 located at. opposite sides of the "pop top" 11. The cylinder end of each of the rams 16 is pivotally secured to a respective pivot mounting (not shown) fixed on top of the roof 10 near the forward end thereof.

Each scissor linkage mechanism 14 comprises a pair of pivotally interconnected links 14', 14", which have one of their ends fixed in horizontally extending channel tracks 18, 19 respectively, their other ends being provided with rollers 21 which rollingly engage along the tracks 18, 19 respectively. The tracks 18 are fitted to and extend along opposite sides of the "pop top" 11 interiorly thereof, whilst the tracks 19 are fixed to the roof 10 and extend along opposite sides of the opening formed in the roof 10 of the

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caravan and which is closed off by the "pop top" 11 when in its lowered position. The tracks 18 are fixed to the wall 12 of the "pop top" 11 on the underside thereof and are spaced a short distance inwardly of the flange 13.

Each connecting linkage 15 comprises first and second links 22, 23 respectively, interconnected by a pivot 24 which pivotally connects the lower end of link 22 to the link 23 intermediate its ends thereof. The upper end of link 23 is pivotally connected to a transverse pin 25 which rotationally supports roller 20, whilst the upper end of link 22 is pivotally connected to transverse pin 26 which rotationally supports a roller 27 carried at the end of piston rod 28 of pneumatic ram 16.

The lower end of link 23 extends beyond pivot 24 and is provided with a freely rotating roller 30 which is arranged to travel up a ramp surface 31 of a fixed wedge-shaped block ei I 32 which is secured to the roof 10, e.g. by means of screws, adjacent the outer side of track 19 intermediate its ends Sthereof. In this embodiment, the link arm 23 has a forked portion which forms a slotted opening 29 in which is snugly received the lower end of the link 22 (refer Fig. 46 In operation, when the rams 16 are initially extended, the Iti links 22 of the linkages 15 rotate in a clockwise direction rrt, about their pivots 24, and the "pop top" 11 is lifted up by a 2 5 small vertical distance. The roller 30 travels upwardly along ramp surface 31, which causes the link 23 to rotate in an It; anti-clockwise direction until it abuts against stop 34 on link 22, this in turn causing the "pop top" 11 to be lifted slightly higher whereupon the upward force of the rams 16 is sufficient to continue the lift of the 'pop top" 11 to its erected position, with the links 22, 23 remaining in a fixed angular relationship.

Due to the confined space within the caravan, the rams 16, with the "pop top" 11 in its collapsed or lowered position, are only very slightly upwardly inclined and hence, are not 6I.

able to exert a resultant upward lifting force sufficient to IIl effect the initial lift of the "pop top" 11 from its collapsed condition. The connecting linkage 15, in combination with the ramp surface 31, remedies this problem by providing a cam-type mechanism to produce a resultant upward lifting force sufficient to effect an initial lift of the "pop top" 11 to a stage whereat the rams 16 can continue the lifting movement of the "pop top" to its erected position.

As shown in Figs. 1 and 2, link 22 of the connecting linkage is provided with a stop member 34 which limits the extent of relative angular movement between the links 22, 23, the stop 34 having two abutment surfaces at right angles to one another, respectively against which an edge of the link 23 abuts when the "pop top" 11 is in its collapsed and erected positions.

0. As shown in Fig. 2, it will of course be appreciated that pivot point 24 must always remain below the over centre position.

I ~p In this embodiment, each of the scissor mechanisms 14 is spring loaded by means of springs 35 extending between the lower ends of links 14', 14" and which assist the opening movement of the "pop top" 11.

The rams 16 are connected to a pressure air supply source (not shown) which can be mounted externally of the caravan 4 and conveniently actuated by a readily accessible manually operable valve. Preferably, the pressurised air supply is a compressor.

It should be appreciated that it may be possible to utilise only one pneumatic ram and for the links 22 of the pair of connecting linkages 15 to be mechanically coupled by means of a rigid connector rod extending between the tracks 18.

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%J A 1 1 1 A brief consideration of the above described embodiment will indicate that the invention provides an extremely simple and effective lifting arrangement for a "pop top" roof type vehicle, and one which can raise and lower the "pop top" without any physical exertion on the part of the operator.

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Claims (9)

1. An improved power lift mechanism for raising and lowering an extendible roof section of a caravan, campervan or similar vehicle (hereinafter "the vehicle") comprising scissor means movably supporting said extendible roof section between raised and lowered positions, said scissor means comprising a pair of opposed scissor linkages each of which comprises elongated links extending between and in movable engagement with a respective upper channel track of a pair of upper channel tracks carried by the extendible roof section adjacent opposite sides thereof and a respective lower channel track of a pair of lower channel tracks located adjacent opposite sides of an opening in which the extendible roof section is mounted, characterised by: a pair of power rams, one at each side of the extendible a &t5 'I roof section, each ram, when said extendible roof section is r~c in its fully lowered position, being approximately horizontal and having its piston rod end guided for movement along a Sa. respective said upper channel track and its cylinder end pivotally attached to a mounting on the roof of the vehicle near to or adjacent an end thereof, and a connecting linkage between the piston rod end of each aaa said ram and the upper end of a respective said link of a ia. S said scissor linkage, constructed and arranged so that during the initial extension of the rams the connecting linkages co- S2. operate with respective engagement surfaces on the roof of the vehicle and by virtue of a cam action exert an upward lifting force sufficient to effect an initial lift of the extendible roof section away from its fully lowered position, whereafter the extendible roof section can be lifted to a fully raised position by virtue of the resultant upward lifting forces provided by the rams.

2. An improved power lift mechanism according to claim 1 wherein each said connecting linkage comprises first and second depending links, the upper end of said first link i 1 being pivotally connected to a respective said piston rod end, its lower end being pivotally connected to an associated said second link intermediate the ends thereof, said second link having its upper end pivotally connected to the end of a said sci~sor link in movable engagement with a said upper channel track, its lower end carrying a ramp engaging member which, during the initial extension of its associated ram, moves upwardly along a fixed ramp surface on the vehicle roof.

3. An improved power lift mechanism according to claim 2 wherein said ramp engaging member comprises a roller which is arranged to rollingly engage said ramp surface.

4. An improved power lift mechanism according to any one of I the preceding claims further comprising limit means for limiting the extent of relative pivotal movement between said first and second links in both clockwise and anti-clockwise 5 directions. I

5. An improved power lift mechanism according to claim 4 wherein said limit means comprises an abutment member fixedly carried by said first link of each said connecting linkage •Iand prejeeting tC ene side r.

6. An improved power lift mechanism according to any one of the preceding claims wherein the connection between each said piston rod end and its associated said first link comprises a S, roller which rollingiy engages along a respective said upper channel track.

7. An improved power lift mechanism according to any one of the preceding claims wherein said power rams are double- acting pneumatically operated rams.

8. An improved power lift mechanism according to any one of the preceding claims when fitted to a vehicle. ii0

9. An improved power lift mechanism according to claim 8 further comprising a compressor mounted on said vehicle, fluid lines interconnecting said compressor and said rams, and a manually operable control valve, remote from said rams, for actuating said rams. An improved power lift mechanism for raising and lowering an extendible roof section of a roof of a caravan or campervan, substantially as hereinbefore described and with reference to and as illustrated in the accompanying drawings. Dated this 16th day of October 1992. THE AIRTIGHT GARAGE PTY LTD By its Patent Attorneys R K MADDERN/& ~ASOCIATES St 11 s i 11 -i~ I I ar C C'S'i ABSTRACT A power lift mechanism for raising and lowering a "pop top" roof (11) of a caravan, utilising a pair of pneumatic rams one at each side of the "pop top" roof each ram (16) being approximately horizontal when the "pop top" roof is in its fully lowered position, and having its piston rod end guided for movement along a respective upper channel track (18) carried by the "pop top" roof with its cylinder end pivotally attached to a mount on the roof (10) of the vehicle, there being a connecting linkage (15) between the piston rod end of each ram (16) and the upper end of a link of a scissor linkage (14) which movably supports the "pop top" roof (11) between its raised and lowered positions, the connecting linkages (15) co-operating with engagement surfaces (31) on the roof of the vehicle during the initial extension of the rams (16) to exert an upward lifting force sufficient to effect initial lift of the "pop top" roof (11) away from its fully lowered position.