GB1576811A

GB1576811A - Air deflector device for vehicles

Info

Publication number: GB1576811A
Application number: GB3226276A
Authority: GB
Original assignee: Warners R A
Current assignee: Warners R A
Priority date: 1977-08-03
Filing date: 1977-08-03
Publication date: 1980-10-15

Description

(54) AIR DEFLECTOR DEVICE FOR VEHICLES (71) I, RoY ALLEN WARNES, a British subject of Hilldene, Hillside, South Brent, Devon, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to air deflector devices for use on vehicles.

When a vehicle is used to tow a large load such as a caravan or covered trailer the air turbulence resulting from the vortex air flow between the towing vehicle and the caravan causes considerable drag, with an adverse effect on the fuel consumption of the towing vehicle. Such drag can also lead to swinging oscillations of the caravan or other trailer, which in some circumstances, particularly when driving in a cross-wind, can prove dangerous.

It has been found possible by means of an air deflector device to reduce considerably the air turbulence between a caravan or trailer and its towing vehicle, and thereby reduce both the overall drag and the tendency of the caravan or trailer to swing.

The present invention accordingly provides an air deflector device comprising a supporting frame having at least one cross member and two legs, each leg being secured directly to a rear face of a baffle plate, the two legs projecting beyond a lower edge of the baffle plate and terminating in screw clamp fittings which are adapted to be secured to opposite sides of a vehicle or vehicle roofrack to support the frame and the baffle plate in an upwardly inclined position, the angle of upward inclination of the baffle plate being adjustable relative to the vehicle roof.

The feet of the frame are preferably adapted to be clamped to the water channels or gutters at opposite sides of the roof of a vehicle.

The baffle plate may be fabricated in wood (for example plywood), sheet metal or sheet plastics material, for example glass reinforced plastics sheet of any suitable thickness, the supporting frame being preferably of tubular metal construction. The cross member of the supporting frame attached to the rear face of the baffle plate preferably extends lengthwise of the latter, so that in use of the device on a vehicle the frame spans the roof of the vehicle.

To enable the device to be adapted to fit vehicles of different widths the baffle plate may be adjustable in length by fabricating it in two or more relatively slidable parts, the cross member of the supporting frame being similarly adjustable in length for example by means of a screw or telescopic section incorporated in the cross member.

The baffle plate may in practice be substantially flat, having lateral edge portions adjacent the legs which are curved rearwardly.

The rearwardly curved lateral edges of the baffle plate reduce turbulence at the sides of the baffle plate when air flows over the latter in use of the device, contributing further to a reduction in the overall drag on the vehicle.

Each of the legs of the supporting frame is preferably adjustable in length and includes means for clamping the leg at its selected length. This enables the baffle plate to be positioned for optimum effect, with its lower edge spaced by a small gap, preferably of the order of a few centimeters, from the roof of the vehicle. The baffle plate may have a recessed or concavely curved lower edge which in the installed position of the baffle plate is spaced from the roof of the vehicle, leaving a gap through which air can flow between the baffle and the roof. A resilient bearing and spacer pad may be provided in the centre of this lower edge, the pad resting upon the roof of the vehicle in the installed position of the device.

In addition to its usefulness in reducing drag on a vehicle towing a trailer or caravan, the device according to the invention is also of use in reducing drag on vehicles having roofmounted loads or on commerical vehicles having high bodies behind their cabs. For example, when a motor car has a roof rack upon which a load is carried, the turbulence resulting from the air flow over the roofmounted load causes considerable drag, which can be reduced by the mounting of an air deflector device according to the invention ahead of the roof rack. For this purpose the legs of the device may be carried upon two support members which are adapted to be attached to or form part of the front of a roof rack, with the baffle plate extending upwardly and rearwardly at the front of the roof rack.

The support members are preferably adapted to be clamped to transverse members at the front of the roof rack. Quick release nuts such as butterfly nuts may be used for this purpose. In a preferred embodiment of the invention the legs of the supporting frame have articulated connections to respective support members which may be clamped to the front of the roof rack and which in use of the device project forwards from the front of the roof rack. The legs can be clamped relative to the support members at any desired angle.

The invention also comprehends a vehicle roof rack fitted with an air deflector device according to the invention at one end. The baffle may be permanently attached to the roof rack, and may be collapsed flat onto the roof rack when the latter is not in use.

The invention will now be described, by way of example, with reference to the accompanying purely diagrammatic drawings, in which: Figure 1 is a side elevation illustrating a vehicle fitted with an air deflector device according to the invention; Figure 2 is a front perspective view of an air deflector device according to one embodiment of the invention; Figure 3 is a rear elevational view of an air deflector device according to another embodiment of the invention; Figure 4 is a side elevation on an enlarged scale of one of the screw clamp fittings for the device of Figure 3; Figure 5 is an end elevation of the screw clamp fitting in the direction of arrow V in Figure 4, and Figure 6 is a purely diagrammatic side elevation illustrating part of a vehicle having a roof rack fitted with an air deflector device according to another embodiment of the invention.

Figure 1 illustrates a motor car 1 towing a caravan 2. Normally the vortices rising from air flow over the roof of the vehicle would result in a region of turbulent air between the vehicle and the caravan, which in turn would result in considerable drag, and would also cause the caravan to tend to yaw or swing while being towed.

The present invention provides an air deflector and stabiliser device incorporating a baffle plate 3 which is fitted at the rear end of the roof of the vehicle, the baffle plate 3 extending upwardly and rearwardly, as shown in Figure 1, so as to deflect the air flow passing over the roof of the vehicle upwardly to pass over the roof of the caravan 2, with substantially less turbulence than would occur in the absence of the baffle plate.

The air deflector device including the baffle plate 3 is fitted removably to the vehicle by means of a supporting tubular frame 4, shown in broken outline in Figure 2, having a straight cross member 5 which is attached to the rear face of the baffle 3 and extends along the length thereof and two substantially parallel legs 6 integral with and perpendicular to the cross member 5, the legs also being attached to the baffle plate 3 to support the latter. The legs 6 extend downwardly, projecting beyond the lower edge of the baffle plate 3 and terminating in respective screw clamp fittings 7 by means of which the legs 6 are anchored to the rain channels or gutters at the sides of the roof of the car 1, at the rear of the car, as illustrated in Figure 1.

The baffle plate 3 which may be of plywood, sheet metal or glass fibre reinforced plastics sheet, has a centrally recessed or cut away lower edge 8 which in the installed position of the stabiliser device follows to a close approximation the transverse curved profile of the roof of the car 1 and is spaced from the roof by a narrow gap. The size of this gap is critical, and should be of the order of two centimeteres to permit a limited flow of air between the baffle plate 3 and the vehicle roof, avoiding the creation of severe vortex flow behind the baffle plate as the car moves forwardly. A rubber bearing and spacer pad 9 is located in the centre of the recessed lower edge 8 and rests upon the roof of the car.

The air deflector device illustrated in Figures 1 and 2 is designed for use on motor cars towing trailers or caravans. A heavy duty version of the air deflector device for use on commerical vehicles is illustrated in rear elevation in Figure 3, the same reference numerals being used to designate components corresponding to those of Figure 2.

The frame 4 of the device of Figure 3 is made up of tubular steel sections, preferably of square cross section but alternatively of circular cross section. The support frame 4 in this heavy duty version has two parallel cross members 5 interconnecting the two legs 6, both the cross members 5 and the legs 6 incorporating telscopic sections, illustrated diagrammatically in Figure 3, to enable the cross members 5 and the legs 6 to be adjusted in length to fit vehicle cabs or roofs of different width.

The supporting frame 4 may include a central reinforcing member (not shown) extending between and interconnecting the two cross members 5 and terminating at its lower end in a bearing member which rests upon the roof of the vehicle and which performs the function of the spacer pad 9. This central reinforcing member may be adjustable in length to press the bearing member onto the roof of the vehicle.

The telescopic legs 6 may have extension portions of circular cross section capable of rotation about their axes within tubular housings to adjust the screw clamp fittings 7 angularly for engagement in rain channels or gutters which are not necessarily parallel to each other.

In both the embodiments of Figures 2 and 3 the baffle plate 3 is adjustable in overall width along with its supporting frame 4 so as to enable the device to be fitted to vehicles of different width. In the two illustrated embodiments the baffle plate 3 has three relatively slidable sections of sheet metal (for example of 8-inch aluminium sheet) which are secured together by bolts 10 attached to and projecting rearwardly from a central flat baffle section 3a and passing through slots 11 in two lateral baffle sections 3b, 3c located behind the central section 3a, the baffle sections being clamped by wing nuts 12 (Figure 3) threaded onto the bolts 10 at a desired overall width.

Alternatively the lateral baffle sections 3b, 3c may be provided with channels at their top and bottom edges, the central baffle section 3a sliding in these channels to enable the width of the baffle to be adjusted.

In the embodiments illustrated in Figures 2 and 3, adjustment of the angular setting of the baffle plate 3 is afforded by providing each clamp fitting 7 with a gutter location plate 13 provided with an arcuate slot 14 in which a bolt 15 projecting outwardly from the adjacent leg 6 of the support frame 4 is located, the bolt 15 having a socket head and being clamped at any desired position along the slot 14 by a nut 16 which is threaded onto the bolt 15. The location plate 13 has a flat lower edge which is adapted to seat in a rain channel or gutter 17, shown in broken outline in Figure 5, at one side of a vehicle roof, the plate 13 being clamped to the gutter 17 by a clamp plate 18 which is bolted to the location plate 13 by two bolts 19. The clamp plate 18 has a lower lip 20 adapted to hook beneath the gutter 17. The location plate 13 has a bearing hole 21 which is concentric with the arcuate slot 14. A bolt 22 acting as a pivot pin for the respective leg 6 of the baffle support frame 4 and having a countersunk head passes through the hole 21 and is engaged in a threaded hole or captive nut on the leg 6.

By slackening the bolts 15 it is possible to adjust the legs 6 and therefore the baffle plate 3 angularly about the pivot axis constituted by the bolts 22 to any desired angular position. The extent of the arcuate slots 14 is such that the legs 6 and therefore the baffle plate 3 can be swung downwardly about the pivot bolts 22 into a horizontal position when the air deflector device is not in use.

It will be seen that in the illustrated embodiments the baffle plate 3 has rounded corners. In addition, the opposite lateral edges of the baffle plate 3 are curved rearwardly, that is, towards the rear of the vehicle in the installed position of the device, as shown in Figure 3, to assist in establishing smooth relatively vortex-free air flow over the baffle plate.

Typical dimensions for the motor car and commerical vehicle version of the device illustrated in Figures 2 and 3 respectively are given below.

Figure 2 version: length of baffle support frame 4 variable between substantially IlOcm and 150cm.

baffle plate 3 variable in length between substantially 120cm minimum and 160 cm.

width of baffle plate 3 at centre, 15 5cm; width of baffle plate at each end, 18cm.

-Ideal clearance between bottom edge of baffle plate and vehicle roof, 2cm.

Figure 3 version: length of frame variable between 168 cm and 244 cm.

baffle plate 3 variable in length between substantially 188 cm and 264 cm.

width of baffle plate at centre 37 cm; width of baffle plate at each end 42 cm; -Ideal clearance between bottom edge of baffle plate and vehicle roof, 6 cm.

The "heavy duty" air deflector device according to Figure 3, suitably dimensioned, can be fitted to the cab of a commercial goods vehicle to smooth the air flow over the cab and the body of the vehicle and thereby reduce the overall air resistance offered by the vehicle.

In practice it will usually be found ideal to set the baffle plate 3 so that it lies in a plane which lies approximately 2cm. above the leading upper edge of the vehicle body as "seen" from the pivot axis of the baffle plate.

The heavy duty commerical vehicle version of the device would normally be fitted at the front end of the cab roof of a vehicle to deflect air upwards over the vehicle body.

Figure 6 illustrates part of the roof of a motor car 1 fitted with a removable roof rack 23. Normally the vortices arising from air flow over a load L on the roof rack would result in a region of turbulent air behind the vehicle, which in turn would result in a considerably increased air resistance.

The present invention reduces this air resistance by providing an air deflector device according to the invention including a baffle plate 3 which is fitted at the front end of the roof rack 23. The baffle plate 3 extends upwardly and rearwardly, as shown, so as to deflect the air flow passing over the roof of the vehicle upwardly over a roof-mounted load L (shown in broken outline) with considerably less turbulence than that which results in the absence of the air deflector device.

The air deflector device is fitted removably to the vehicle roof rack 23 by means of two support members 24 which are clamped to the front end of the roof rack 23 and which extend horizontally forwards from the front edge of the roof rack. The front ends of the support members 24 are provided with upturned lips 26 at their lower edges forming respective channels to which the respective screw clamp fittings 7 of the air deflector device are fitted analogously to the fittings of the deflector device to the roof gutters as described earlier with reference to Figures 4 and 5. The legs 6 of the baffle support frame can therefore be supported at the desired angle by the support members 24, can be pivoted rearwardly to lie flat upon the roof rack 22 when the baffle plate 3 is not in use.

The rearwardly inclined baffle 3 may alternatively be supported by a load carried on the roof rack.

Each support member 24 comprises two plates or blocks clamped together by bolts and wing nuts with at least two of the transverse members of the roof rack 23 clamped therebetween, to provide a firm anchorage for the members 24, the bolts extending vertically between the two plates or blocks, shown diagrammatically in Figure 6. Alternatively, the two plates or blocks of the support members 24 may be arranged on opposite sides of respective vertical side rails of the roof rack, the bolts extending horizontally between the plates or blocks to clamp the support members 24 to the sides of the roof rack.

An arrangement such as that described with reference to Figure 6 may be used to support a baffle at the rear end of a roof rack to deflect air upwardly at the rear of a vehicle towing a caravan or trailer, similarly to the device shown in Figure 1, without clamping the device directly to the roof of the vehicle.

WHAT I CLAIM IS: 1. An air deflector device comprising a supporting frame having at least one cross member and two legs, each leg being secured directly to a rear face of a baffle plate, the two legs projecting beyond a lower edge of the baffle plate and terminating in screw clamp fittings which are adapted to be secured to opposite sides of a vehicle or vehicle roofrack to support the frame and the baffle plate in an upwardly inclined position, the angle of upward inclination of the baffle plate being adjustable relative to the vehicle roof.

2. A device as claimed in Claim 1, in which the screw clamp fittings of the supporting frame are adapted to be clamped to the water channels or gutters at opposite sides of the roof of a vehicle.

3. A device as claimed in Claim 1 or Claim 2, in which the baffle plate is adjustable in length, comprising two or more relatively slidable parts, the cross member of the supporting frame being similarly of adjustable length to enable adaptation of the device to fit vehicles of different widths.

4. A device as claimed in any one of the preceding claims, in which the baffle plate is substantially flat, having lateral edge portions adjacent the legs which are curved rearwardly.

5. A device as claimed in any one of the preceding claims, in which each of the legs of the supporting frame is telescopically adjustable in length and includes means for clamping the leg at its selected length.

6. A device as claimed in Claim 5, in which each telescopic leg has an extension portion of circular cross section capable of rotation about its axis to adjust the respective screw clamp fitting angularly.

7. A device as claimed in any one of the preceding claims, in which the baffle plate has a centrally recessed, cut away or concavely curved lower edge which in the installed position of the baffle plate is spaced from the roof of the vehicle.

8. A device as claimed in Claim 7, in which the lower edge of the baffle plate is spaced in use of the device about 2 centimetres from the roof of the vehicle.

9. A device as claimed in Claim 7 or Claim 8, in which a resilient bearing and spacer pad is provided at a central part of the lower edge of the baffle plate to span the gap between the said lower edge and the vehicle roof.

10. A device according to any one of the preceding claims, in which the legs are carried upon two support members which are adapted to be attached to or form part of the front of a roof rack.

11. A device as claimed in Claim 10, in which the legs of the supporting frame have articulated connections to the respective support members.

12. A vehicle roof rack fitted at one end with an air deflector device according to Claim 10 or Claim 11, the baffle plate of the device having a position of use in which it is inclined upwardly and rearwardly at the front end of the roof rack.

13. A vehicle roof rack as claimed in Claim 12, in which the baffle plate has a collapsed position in which it lies flat upon the roof rack when not in use.

14. An air deflector device for vehicles substantially as herein described with reference to and as shown in Figures 1 to 5 or Figure 6 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. front end of the roof rack 23 and which extend horizontally forwards from the front edge of the roof rack. The front ends of the support members 24 are provided with upturned lips 26 at their lower edges forming respective channels to which the respective screw clamp fittings 7 of the air deflector device are fitted analogously to the fittings of the deflector device to the roof gutters as described earlier with reference to Figures 4 and 5. The legs 6 of the baffle support frame can therefore be supported at the desired angle by the support members 24, can be pivoted rearwardly to lie flat upon the roof rack 22 when the baffle plate 3 is not in use. The rearwardly inclined baffle 3 may alternatively be supported by a load carried on the roof rack. Each support member 24 comprises two plates or blocks clamped together by bolts and wing nuts with at least two of the transverse members of the roof rack 23 clamped therebetween, to provide a firm anchorage for the members 24, the bolts extending vertically between the two plates or blocks, shown diagrammatically in Figure 6. Alternatively, the two plates or blocks of the support members 24 may be arranged on opposite sides of respective vertical side rails of the roof rack, the bolts extending horizontally between the plates or blocks to clamp the support members 24 to the sides of the roof rack. An arrangement such as that described with reference to Figure 6 may be used to support a baffle at the rear end of a roof rack to deflect air upwardly at the rear of a vehicle towing a caravan or trailer, similarly to the device shown in Figure 1, without clamping the device directly to the roof of the vehicle. WHAT I CLAIM IS:

1. An air deflector device comprising a supporting frame having at least one cross member and two legs, each leg being secured directly to a rear face of a baffle plate, the two legs projecting beyond a lower edge of the baffle plate and terminating in screw clamp fittings which are adapted to be secured to opposite sides of a vehicle or vehicle roofrack to support the frame and the baffle plate in an upwardly inclined position, the angle of upward inclination of the baffle plate being adjustable relative to the vehicle roof.