AIR DEFLECTOR FOR MOTOR VEHICLES

Abstract: An air speed sensitive variable pitch air deflector comprises an airfoil (14) pivotally mounted on a vehicle roof (11) adjacent the upper edge of a rear or tailgage window (13). At low vehicle speeds, the deflector occupies a normal position in which it deflects air downwardly over the window to assist in cleaning the window. Above a predetermined vehicle speed, the flow of air over the airfoil changes the pitch of the airfoil so that the airfoil offers less drag and the fuel economy degradation produced by the braking effect of the air deflector can be reduced.

Description: SPECIFICATION TITLE AIR DEFLECTOR FOR MOTOR VEHICLES SCRi This invention relates tD air deflectors. In U.S. Patent No. 3,56,044 the statement is made "it is common in connection with autozobiles of the station wagon type to utilise wind deflectors adjacent the rear window in an effort to prevent the accunulation Or dirt and other foreign matter On the rear wiow. his accumulation results form the partial vacuum formed immedisialy behind the vehicle as the latter is driven forwardly tsee U.. Patent No. 3,097,882). the solution to the partial vacuum proble@ as disclosed in ooth the above cited patents (which are representative of the prior artj comprities the placement of a tixed deflector element adjacent the vehicle rear window. The fixed deflector is mounted so that it projects into the airatream flowing across the top of the moving vehicle and turns the airstream downwardly across the roar window. The downward flow of air breaks the partial vacuum and prevents the adhesion of dirt and other particulate luiittor to the widnow surface. The rixeci deflector has a disadvantage in that, as the vehicle speed increases, the fixed deflector acts as @ air brake. This results in a uegradation in fuel economy. i'he present invention proviues an air defl@ctor assembly for a motor vehicle comprising an airfoil, support means adapted to be Secured to the vehicle adjacent the upper dege of the rear window of the vehicle, and pivot means coupling tfle airfoil to the support zeans for swinging movement about a pivot axis between a first position in which the airfoil deflects air flowing thereover downwardly, and a second pasition in which the drag exerted by the airfoil on the air flowing thereover is reuucea, the airfoil being movable from the first position into the second position by the pressure exerted thereon by the air flowing over the airfbil. In use, the air deflector assembly is mounted on suitable support means on a vehicle roof adjacent the upper edge of a rear or tailgate window. rreferably, the airfoil is coupled to the support means by suitable pivot means that per mit frco swinging movement about a pivot axis defined by the pivot means. The airfoil is swingably om a maxi@um pitch position relative to the vehicle roof in which it creates an air brake effect on ine vehicle to a minimum pitch position at which it lits substantially parallel to tht: of, thereby nullifying tht air but effect. The airfoil, of its own weight. maintains the maximum pitch; position in which it acts as an air ezefle ctor directing the airstream comnwardly over the rear window of the vchicle until the vehicle apeed attains a velocity at which the pressure of the ai ratream causes sufficient lift on the airfoil to swing the latter upwardly toward pitch position relative to the vehicle roof. A preferred emboaiment of the invention will now be described, by way of example only, with reference to the accompanylng drawings, in which : Fig. l is a porspective view of the upper rear end of a station waeon with mii aLr ueflector shown in its maximum pitch position relative to une vehicle roof; in accordanc with the invention lig. 2 is a view in part similar to Fig. 1, with the air speed sensitive variable pitch air defctor shown in its minimum pitch position relative to the vehicle roof; Fig. 3 is an enlarged fragintary elevational view looking in the direction of the arrow 3 in Pig. 1; Fig. 4 is a view in part sectional taken substantially on the line 44 of sig. 3, showing Oft embodiment of a detent mtans for maintainine the air deflector at its maximum pitch position relative to the vehiche roof; ; Fig. 5 is a view in part similar to rig. 4, illus tracing a second embodiment of a detent means for maintaining the air deflector in maximum pitch position; big. 6 is a view in part similar to Fig, 4, illustrating a third embodiment or a detent @@ans for maintaining the air deflector either in maximum pitch position or in minimum pitch position relative to the roof; and tig. 7 is a section view on the line 7-7 of Fig. 6. Referring now to the drawings, an air speed sensitive variable pitch air deflector, generally designated 10, is shown mounted on ale roof 11 of a station wagon type vehicle baving a rear boor or tailgate 12 provied @lth a window 13. The air deflector 10 is shown mounted substantially in the sa.e manner as the air deflector disclosed in U.S. reissue Patent No. Rk.26,538. The latter patunt discloses an air deflector comprising an airfoil fixedly secured at eadh end to a mounting bracktt that has an upper end portion telescopically connected to the rear cnd of a side rail of a roof mounted luggage rack, the airfoil being positioned directly abuse and slightly rearwardly of the rear window of the vehicle. t e air dtflector 10 comprises an airfoil 14 that also is adapted to be mounted on tht; rear ands 15 of side rails 16 of a roof mounted luggage rack 11, tile airfoil 1, being positioned uirectly above and sliltly rearwardly of the rear wintlow 13 of the vehicle. shU airfoil 14 is supported on brackets 18 that have upp r end portions knot visible) telescopically engaged with the ends 15 of the sine rails 16. As best seen in Fig. 3. the airfoil 14 is reinforcen on its underside at each end with a right angle reinforcing mamber 19 to which is anchored a laterally pro acting pivot pin 21. rhe pivot pin 2i extends into the support bracket 18 anci couples the airfoil 14 to the brackets 18 for free swinging movement of the airfoil about a pivot axis extending longitudinall of the airfoil, the pivot axis being defined by the pivot pins 21. The pivot pins 21 are located adjacent the top of the airfoil 14 so that the latter, under its own weight, maintains a substantially vertical or maximum pitch relationship to the plane of the vehicle roof. The brackets 18 and the airfoil 14 are contoured to provide a substantially flush appearance from the rear ksee Fig. 1). Suitable stops (not shown) may be provided to limit the Yig. 1 or the at rest position of the airfoil 14. Ihe airfoil 14 is capable of swinging from a first or maximum pitch position of Fig. 1 to a second substantially norizontal or zero angle of attack position, which mey also be defined as the minim pitch position, as shown in Fig. 2. This is for the purpose of overcoming on diaadvantage of an air deflector tnat is fixed reiative to the vehicle roof. A fixed deflector, maintainco at a maximum pitch position in which it is most effective to deflect an airstream domnwardly over the rear window, also becomes an effective air brace resisting forward icire- ment of the vehicle as the vehicle speed is increased. The air- foil 14, for example, may be designed and weighted so that it maintains its Fig. 1 or maximum pitch position at vehicle speeds from zero to 30 milcs per hour so that it is effective to perform the airstream defl@cting-window cleaning function. At speeds below 30 miles per hour, the aerodynamic urag or air brake effect is not grent enougt to affect the miles-per-gallon efficiency of the vehicle to any great degree. As the vehicle speed approaches 30 milts per hour, the airstream flowing over the vehicle roof begins to exert a lift force on the airfoil sufficient to cause the latter to swing upwardly in a clockwise direction, as @ewed in rigs. 1 anti 2 of the drawings. nt 50 miles par flour, the airfoil achieves a substantially horizontal or minimum pitch attitude. Although the effectiveness Cf the airfoil as an airstream deflector for deflecting the airstream in winiow cleaning dir ctian is nullified, the aerodynamic drag or air brake effect is also oub- stantially nullilied. @very ounce of fuel that is of extreme importance, since, in the United States of Am@rica, vehicle manufacturers are required to be increasingly stricter regarding corporate average fuel economy standards with each passing year. With neference to Yig. 2, a centrally positioned stanchion 22 appears visible beneath the uplifted airfoil 14. This stanchion 22 y be provided to prevent deflection of the airfoil in a dir ction transversely of the airfoil pivot axis. Under ertreme conditions, such deflection could result in permanent warping or bending of the airfoil. This typically occurs by someone leaning against the airdeflector while placing articl@s in the luggage rack or while removing artiches from the luggage rack. The stanchion 22 carries a pivot pin 23 axially aligned with tne pivot pins 21 and journal@@o in a rib 24 extending trarsversely of the pivot axis of the airfoil integral with the other sioe of tit: latter. lt will be apparent that similar stanchiona stay be us@@ to support the encia of the airfoil on the vehicle roof in the absence of a luggage rack 17 on which the air deflector assembly way be mounted. Inasmach as sr me vehicle ovzrs may prefer that the air @eflector assembly embodying the present ilvention be pro viaea rith a manual ovtrriile capability, this may be provided as shorn in l'igs. 4, 5 and 6i. In Fig. 4, the manual overriue comprises a detent in the lorm of a ba 1 25 mounted in an aperture 26 in the stanchion 22. The aperture 26 is radially aligned with the pivot axis of the pivot pin 23. The ball 25 is spring-loaded by a compre ion spring 27 beld in the aperture 26 by a set screw 28. The ball 25 is adapted to bear against the circular end surface 2',1 of an annular extension 31 of thg rib 24. In maximum pitch position of the airfoil 14, the ball 25 is seated in a locking recess 32 i'.' the circular end surface 29 where it is held aeainst displacement by the force exerted on the airfoil by an airstream. @orceable rotation in counter-clockwise direction, as viewed in Fig. 4, of the airfoil 14, results in dislodgement of toe detent ball 25 from the recess 3?. he ball 25 is then free to roll against the slightly depressed circular surface 33 of the circular end surface 29 as the airfoil moves between the tig. 1 and rig. 2 positions. Should the vehicle operator decide again to lock the airfoil in its maximum pitch position, manual pressure exerted on the airfoil in a clockwise direction will be required to seat the ball 25 in the locking recess 32. Pig. 5, illustrates an alturnative construction for a manual override which comprises a detent in the form of a pin 34 extending through the stanchion 22', the axis of the pin 34 paralleling the axis of the pivot 23. In this embodiment, the rib 24' of Qk airfoil L4 is lbrmed Of a plastic material. The rib 24' has an annular ertension 31' which has a resilient arcuate appendage 35 that terminates in a flat end 36. In the at r@st or maximum pitch position of Uke airfoil 1', the flat ena 36 rests against the surface of ' the pin 34. Upon sufficient manual force being exerted in a counter-clockwies direction on the airfoil, tile resilient appendage 35 will yield toward the pivot pin 23 axis whereby the pin 34 will ride over the arcunte surface 37 of the appendage ptrmitting the airfoil to function as a variable pitch air uflctor as the vehicle speed is increasea to the critical ve)ocity. A further alternative construction for a manual override is illus fated in Figs. 6-7. In this embodiment, the manual override not only pe rmits tile airfoil 14 to be locked in a zaxi- mum pitch position as seen in iig. 1, but also permits the airfoil 14 to be locked in the minimum pitch position of rig. 2. The annular extension 31" of the lib 24 is provided in its circular periphery with two spaced locking notchen 38 and 3@, Eitner notch 38-3 is adapted to reoeive a detent in tne form ot a baii 41. ine bail 41 15 positioned to re cammed tnrough an aperture 42 un the wali 43 of a cylindrical bore 44 in the stanchion J. Slicable in the bore .,4 is a push-button 1+6 having a conical cem surface 47. As shown in Figs. 6 and 7, the push-button 46 is positioned so that the ball 41 is not in engagement with either notch 38 or 39. If tie vehicle operator decides that he would prefer to have the airfoil 41 locked in its maximum pitch position1 a s Shown in J"ig. 6, it is only necessary for him to push the push-button 46 in a direction to cause the cam surface 47 to drive the ball 41 though the aperture 42 into engagement with the notch 38. The airfoil 14 then would be held against free swinging movement in a counter-clockwise direction, as viewed in Fig. 6. Similarly, if the vehicle operator decides he would like to have the airfoil 14 maintained in its minimum attitude position, he would first be required to align the notch 38 with the ball 41 by raisin; the airfoil 14 to a zero angle of attack or a minimum pitch position and then, by manipulation of the puchbutton 46, drive the ball 41 through the aperture 42 into engagement with the notch 39. Thus, with the manual overnriae of this embociment. the airfoil 14 may be left in a freely swingable condition, or it Jy be; locked in eit@er its raised or down pos ition. it will be understood that the invention is not to be limitwd to the exact construction shown in the drawings, but that various changas and modifications may be may be made thereto.

Claims: 1. an air deflector assembly for a rotor vehicle cos prising an airfoil, support means adapted to be secured to the vehicle aajacent the upptr edge of the rear window of the vehicle and pivot means coupling U airfoil to the support m@ans for swinging ov'nt about a pivot axis between a first poaition in which the airfoil deflects air flowing thereover domnwardly, and a s cond position in which the drag exerted by the airfoil on the air f lovin thereover is reduced, the airfoil being movable from the first position into the second position by the pressare exerted tri-reon by the air flowing over the airfoil. 2. an air defh@ctor according to Claim 1, in which the support means and the airfoil have releaseble @etent moans for locking the airfoil in at least in tb first position. 3. an air defector assembly according to Claim 1 or Claim 2, where in the support m@ans incl@ues a support member supporting tile airfoil at tao: end thereof ano at least one stanchion positioned intermeoiate the end support members to resist defloction of the airfoil in a dirsction transversely of tne pivot axis. 4. An air defl@ctor assembly accordng to Cla. 3, in which a detent means is mounted at least on the one stanchion, the uetent means being manually selectively engageable with a detent means engageable portion of the airfoil to lode the seme in its first position. 5. A motor vehicle having an air deflector assembly according to any one of claims 1 to 4 mounted on is roof adjacent the upper ede of its rear window.

Inventors: CHABOT, JAMES VINCENT, HOLKA, THOMAS C, MCNALLY, THOMAS E
Applicants: FORD FRANCE SOCIETE ANONYME, FORD MOTOR COMPANY, FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1979
Main classification: B60J1
IPC codes: B62D35, B60J1, B60S1