GB1602532A - Drag-reducer for land vehicles - Google Patents

Description

(54) DRAG REDUCER FOR LAND VEHICLES (71) We, THE RUDKIN-WILEY CORPORATION, a corporation organised and existing under the laws of the State of Connecticut, United States of America, of 760 Honeyspot Road. Stratford, Connecticut, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be perforrzed. to be particularly described in and by the following statement: The present application is an application for a Patent of Addition to U.K. Specification No. 1544478 (App. No. 51996/76).

This invention relates to practical means for substantially closing off the entire gap area between the tractor and trailer of a semi-trailer or full trailer rig. Similar means may also be utilized in car-trailer combinations and railroad box cars.

The basic concepts and reasons for sealing this gap are taught in U.S. Patent No.

3,697,120. This patent points out that when a tandem type vehicle of conventional design encounters wind forces at yaw angles.

the flow of air can pass laterally through the gap region. resulting in increased aerodynamic drag. This is caused by a flow separation and increa turbulence along the lee side of the following body. The effect is increased when the corners of the trailing body are sharp, chamfered or moderately radiused as in the case of present-day vehicles.

The concept of stabilizing the normal rotating vortex system in the gap region is well documented in the above referenced U.S. patent and, as the patent teaches, the ideal situation would be to completely close the gap by a stabilizer plate. However, the patent points out that due to the practicalities of maneuvering a tractor-trailer combination, it is only feasible to partially close the gap. For this reason, the full gap-sealer is illustrated only on non-articulated, or rigid chassis trucks. A substantially complete gap sealer is illustrated for two trailing vehicles such as railroad box cars. This approach can also be utilized in the case of trucks rigged to haul one semi-trailer plus one or more full trailers, however the geometry and pivot points in these types of trailers are such that an interference can come about unless the gap size is increased.

Previous means for substantially sealing the gap in semi-trailer trucks have consisted of rigid fins attached to the front face of the trailer. These fins have been dimensioned so as to fill as much of the gap as possible, consistent with the turning and pitching attitudes of tractor-trailer rigs in normal operation.

If one assumes an ideal condition consisting of a matched tractor and trailer which always run together as a set, and further assumes an almost n,erfectly flat roadbed, then the trailer mounted fin could, in fact, extend almost the entire distance from the front of the trailer to the back of the tractor, without encountering an interference. This is true because the pivot point of a typical tractor and semi-trailer rig is located under the trailer and therefore in any turning maneuver on level ground, the tractor falls away from the leading vertical edge of the trailer-mounted fin. Further, there would be no pitching effect such as the tractor climbing a curb or inclined ramp while the trailer is still on level ground. This condition causes the gap to close at the top and could cause an interference at the top of the cab.

In actual trucking conditions, however, a rigid full gap vortex stabilizer is not practical because of the occasional pitching between tractor and trailer. Also the distance between the rear of the tractor and the front of the trailer is occasionally altered by the trucker, utilizing a sliding fifth-wheel.

Therefore a rigid, trailer mounted vortex stabilizer might work properly when sized for a 60 inch gap, but would constitute an interference if the gap were closed by sliding the fifth-wheel assembly forward by, say, 12 inches.

This invention, then, relates to practical means for closing the gap between tractor units and trailer or trailing units and is a modification in the gap sealing means.

Accordingly the present invention consists of a modification of a drag reducer as claimed in claim 1 of British Patent Specification No. 1,544,478 wherein said gap sealing means are adapted to be mounted such that the forward edge is, in use, in juxtaposed spaced relationship to said rear panel of the leading element.

In order that the present invention may be more readily understood, various embodiments thereof will now be described by way of example and with reference to the accompanying drawings, in which: Figure I is a top plan view of a tractor and semi-trailer with an alternative embodiment of the drag reducing apparatus of the present invention shown mounted to the tractor, with its deflecting capabilities shown in phantom; Figure 2 is a perspective view, partially broken away, of a tractor with the drag reducing apparatus Figure 1 mounted thereto; Figure 3 is a cross-sectional top plan view of the drag reducing apparatus of Figure taken along line 13-13 of Figure 2; Figures 4-8 are cross-sectional top plan views of various alternative embodiments of the drag reducing apparatus of the present invention; Figure 9 is a perspective view, partially broken away, of a tractor with an alternative, foldable embodiment of the drag reducing apparatus of the present invention mounted therewith; Figure 10 is a top plan view of the drag reducer of Figure 9 mounted in its extended position with a conventional trailer; Figure 11 is a top plan view of the drag reducer of Figure 9 mounted in its folded position with a refrigerated trailer; Figure 12 is a perspective view, partially broken away, of a tractor with an alternative embodiment of the drag reducer of the present invention mounted therewith; Figure 13 is a top plan view of the drag reducer of Figure 12 mounted in a gap of about 48 inches; Figure 14 is a top plan view of an alternative embodiment of the drag reducer of Figure 12 mounted in a gap of about 60 inches; and Figure 15 is a top plan view of an alternative embodiment of the drag reducer of Figure 12 mounted with a refrigerated trailer.

Specific Description Referring to the drawings, Figure 1, 2 and 3 illustrates a typical tractor-trailer rig in which a gap exists between tractor 2 and semi-trailer 1. In practice this gap may range anywhere from approximately twenty to one hundred inches depending upon various fleet and motor vehicle regulation requirements.

The tractor 2 and semi-trailer 1 are provided with a gap-sealing drag reducer 31 which incorporates a rigid portion 33 and a separate flexible portion.

Flexible portion 32 comprises a substantially uniform cross-sectional area and is constructed from material which resists bending when exposed to moderate loads while also flexibly bending under high pressure loads. This construction assures that gap sealing drag reducer 31 remains substantially stiff during normal driving when exposed to moderate to heavy crosswinds, while also being flexibly moveable when exposed to the high load pressure encountered when in contact with the tractor surfaces. Presently, high density semi-rigid polyethylene is preferred for flexible portion 32, but other similar materials such as rubber, polyviny bichloride, acetates, and polycarbonates, have been found to perform equally well.

The desired flexibility which flexible portion 32 must be capable of achieving can best be understood by referring to Figure 1.

As shown in phantom therein, tractor 2 incorporates a fifth wheel or pivot point 35 about which tractor 2 will arcuately turn.

As previously discussed, prior art vortex stabilizers are not capable of achieving complete gap closure due to the necessity for complete maneuverability of the tractor with respect to the trailer. This maneuverability has now been achieved by the present invention. In this particular embodiment of the present invention, the prior art problems are overcome by having a flexible portion 32 formed in gap sealer 31 which is capable of being laterally moveable in response to the forces generated during contact with the trailer surfaces. Furthermore, the lateral moveability and deflection of flexible member 32 is achieved without injury to either the trailer wall or flexible member 32.

In order to add further stiffening to flexible member 32 for bending resistance during heavy crosswinds, optional leaf springs 39 can be employed. As shown in Figures 2 and 3, leaf springs 39 are secured to rigid portion 33, by mounting means 37, extending therefrom partially along flexible member 32. It is important to note, however, that leaf springs 39, only extend a short distance along flexible member 32, in order to assure that leaf springs 39 will not contact the tractor surface.

In Figure 2, optional support legs are shown. Support legs 36 incorporate base members 40, which are secured directly to chassis frame rails 41 of tractor 2, and upstanding leg portion 42, which are mounted directly to rigid member 33 of gap sealer 31. In certain situations, it may be more advantageous and convenient to mount gap sealing drag reducer 31 directly to chassis frame rails 41 instead of to the rear wall of tractor 2. If this is desired, support system 36 is easily employable to achieve this mounting situation. Although mounting system 36 has been shown and described in combination with gap sealing drag reducer 31, any of the other gap sealing drag reducing embodiments shown and disclosed in this present application can be similarly mounted.

In Figures 2 and 3, optional protective contact discs 38 are shown mounted to the exposed edge of flexible member 32 of gap sealing drag reducer 31. In the preferred embodiment, a plurality of protective contact discs 38 are mounted along the exposed edge of flexible member 32 in order to assist in the smooth, flexible deflected movement of gap sealing drag reducer 31 over any external trailer ribs and other trailer protuberances. Also, the use of discs 38 assures the existence of sufficient clearance between the edge of flexible portion 32 of gap sealer 31 and the trailer surface itself, thereby eliminating any possible chafing of electrical or pneumatic cables and hoses interconnected between the tractor and the trailer.

In Figures 4-7, alternative embodiments of the gap sealing drag reducer 31 are shown. In each of these embodiments, gap sealing drag reducer 31 comprises a rigid portion 33 and a flexible portion having a variety of dimensional and structural configurations. Each of these flexible members is secured to rigid member 33 by mounting means 37.

In Figure 4, flexible member 50 comprises an overall elongated oval shape with rounded corners being incorporated therein. In Figure 5, elongated tapered flexible member 51 is shown with a rounded terminating end. Similarly, in Figure 6, elongated flexible member 52 is shown with a slightly tapered construction up to its terminating end which it is enlarged to form a substantially circular cross-sectional area. Although each of these flexible members differ in their physical appearance, they all provide bending resistance when exposed to heavy crosswinds, and supple damage-free flexibility when exposed to heavy pressures encountered when the trailer surfaces are physically contacted.

By employing flexible members 50, 51 or 52, the clearance provided by protective discs 38 for cable connections can be eliminated, since no chafing occurs with these configurations. It has been found that the chafing is eliminated due to the waxy, slippery nature of the polyethylene employed in the construction of flexible members. Furthermore, a spring support member interconnecting the flexible member with rigid member 33 is also unnecessary, since the elongated enlarged cross-sectional areas of the flexible members provide the stability required under the medium to heavy wind loads.

In Figure 7, a substantially solid flexible member 53 is shown with a tapered crosssectional area. By providing a root section 54 of flexible member 53 which is secured to rigid member 33 by fastening 37, the necessity for any leaf-spring device is eliminated.

The root section 54 of flexible member 53 provides a desired stiffening effect in order to assure that flexible member 53 resists high wind forces which attempt to deflect it, while still being capable of damage-free deflection when the surface of flexible member 53 comes in contact with a surface of the trailer. Flexible member 53 may be tapered on both of its surfaces or may be a constant wall thickness, with a transversely corrugated or fluted construction.

In Figure 8, flexible member 32 of Figure 2 is shown with an elongated, substantially circular cross-sectional, tubular member 38A mounted along the rear edge of flexible member 32. Tubular member 38A is also shown in Figure 2 in dotted lines. In most applications, tubular member 38A is preferred for ease of installation and assurance of protection along the entire side edge of flexible member 32. Furthermore, tubular member 38A can be bolted or otherwise fastened directly to flexible member 32, thereby assuring its secure position retention.

It has been found that the actual location of the gap sealing drag reducer of this invention in the gap between tractor 2 and trailer 1 is not a critical factor. Consequently, although the various embodiments of gap sealing drag reducer of this invention have been shown in the drawings of this disclosure in a position which is substantially along the center line of the side-to-side dimension of the gap. However, as shown in Figures 9, 10 and 11, the gap sealing drag reducer of the present invention can be also mounted along the chassis frame rail of tractor 2. In many situations, this position is extremely desirable since supporting hardware can be eliminated and the gap sealing drag reducer can be directly supportingly mounted to the chassis frame rail. Consequently, it should be clear that any of the embodiments of the gap sealing drag reducer of the present invention which are detailed in the other drawings are also capable of mounting along the chassis frame rail and, similarly, the embodiment of Figure 9 can certainly be mounted in any alternative, desired position in the gap.

As discussed above, it has been found to be more economically feasible to mount the gap sealing drag reducer to the tractor as opposed to the trailer. This has been found to be more desirable since most fleets have more tractors than trailers. Consequently, the tractors in any particular fleet are in comparative constant use, while many trailers may be unused.

Furthermore, it has been found that most fleets which carry general unrefrigerated cargo also have some refrigerated trailers.

Consequently, although the various embodiments of the gap sealing drag reducer described in detail hereinbefore could be employed with refrigerated trailers, a hinged, pivotable embodiment of the gap sealing drag reducer is preferred.

In Figures 9, 10 and 11, gap sealing drag reducer 60 is shown, incorporating a rigid portion 65 and a flexible portion 66 which is hingedly secured to rigid portion 65. In this way, drag reducer 60 is easily pivoted from a fully extended gap filling position to a folded, partial gap filling position. When drag reducer 60 is in the folded position, a conventional refrigerated trailer can be easily attached to the tractor.

As best seen in Figure 9, the preferred embodiment for hingedly connecting flexible portion 66 with rigid portion 65 is achieved by sandwiching the hingedly connected end of flexible portion 66 between two support plates 62 and 63. Plates 62 and 63 are interconnected in order to assure secure and complete supportive maintenance of flexible portion 66 therebetween.

The assembly is then completed by mounting hinge means 67 along one edge of rigid member 65 and support plate 62.

Although numerous hinge systems can be employed, Figure 19 shows for simplicity, a plurality of typical hinges 67 mounted to rigid member 65 and support plate 62 along their substantially vertically disposed abutting edges.

In the preferred embodiment, the hinged gap sealing drag reducer 60 also incorporates locking means 68 for securely maintaining drag reducer 60 in its extended, gap-filling position. Although a plurality of locking apparatus can be employed, Figure 19 depicts an arcuately pivotable bar and latch assembly 68 in which the bar is pivotally secured to rigid member 65 and the latch mechanism is mounted to support plate 63. In this way, pivotable gap sealing drag reducer 60 can be locked in its fully extended position using locking apparatus 68, and then when desired disengaging locking apparatus 68 and quickly and easily pivoting flexible member 66 about the vertical axis established by pivot means 67.

If desired, quick disconnect means 73 can be mounted to latch means 68 in order to allow simultaneous disconnection of both locking means in a single operation. Furthermore, foldback latching means 70 and 71 can also be incorporated in order to assure that flexible member 66 is securely maintained in the folded, pivoted, partial gapfilling position. Although a plurality of various securing means could be employed, a handle 70 and cooperating eyebolt 71 are shown as an example of the securement apparatus that can be used.

In Figures 9 and 10, hinged gap sealing drag reducer 60 is shown in its fully extended, gap-filling position, substantially closing the gap between tractor 2 and trailer 1. In Figure 11, foldable, pivotable gap sealing drag reducer 60 is shown in its folded and latched configuration with refrigerator unit 76 mounted to trailer 1 and occupying a substantial portion of the gap area. With folded, pivotable gap sealing drag reducer 60 in its folded position, rigid member 65 and flexible member 66 substantially fill the exposed gap area and provide the gapsealing effect for the reduction of drag as the refrigerated tractor and trailer combination moves through a fluid.

As shown in Figures 9, 10 and 11, the hinged, foldable gap sealing drag reducer 60 is mounted in the gap between tractor 2 and trailer 1 directly to one of the rearwardly extending chassis frame rails 75 of tractor 2.

As shown in Figure 19, gap sealing drag reducer 60 can be securely mounted to chassis frame rail 65 using support members 69 which are securely mounted to rigid member 65 as well as securely mounted to one of the chassis frame rails 75. However, as discussed above, although the mounting of drag reducer 60 to chassis frame rail 75 is preferred, drag reducer 60 can be mounted in the gap between tractor 2 and trailer 1 in any alternate location.

It has also been found that the leading edge of the gap sealing drag reducer of this invention can be spaced away from the rear wall of the tractor a distance of up to about 18 inches without substantially affecting the efficiency of the drag-reducer. Consequently, in many applications, the substantially solid plate, shown and thoroughly disclosed in the embodiments enumerated above, can be eliminated leaving only the flexible member substantially by itself serving as the gap sealing drag reducer.

In Figure 12, a gap sealing drag reducer 80 of this embodiment is shown. Gap sealing drag reducer 80 incorporates a flexible, bendable portion 81 which is securely mounted to a rigid supporting strut 82.

Rigid supporting strut 82 is securely mounted to chassis frame rail 75, thereby providing a rigid, secure support system to which flexible portion 81 is securely held and about which flexible portion 81 is capable of freely arcuately bending.

As described above, in detailing the construction of gap sealing drag reducer 31 of Figure 2 and 60 of Figure 9, gap sealing drag reducer 80 comprises flexible portion 81 which is constructed from material which resists bending when exposed to moderate loads while also flexibly bending under higher pressure loads. As a result of this construction, flexible portion 81 remains substantially stiff and maintains the gap substantially closed during normal driving when flexible portion 81 is exposed to moderate to heavy crosswinds.

However, when higher pressure loads are encountered, generally experienced when contact is made with the tractor surface during parking maneuvers, flexible portion 81 flexibly moves out of position in order to prevent injury to the tractor surface. Gener ally, high density semi-rigid polyethylene is preferred for flexible portion 81, but other similar material such as rubber, polyviny Ichloride, acetates, and polycarbonates have been found to perform equally well.

In the preferred embodiments, both gap sealing drag reducers 60 and 80 incorporate elongated protective end caps mounted to the rearwardly facing edges of flexible por tions 66 and 81. As discussed above. end cap 38A preferably comprises a substantially circular cross-section and extends from the top to the bottom of flexible member 81 along the rear edge thereof. In this way, two-fold protection is provided, since both the trailer surface and the associated hard ware are protected, as well as the edge of flexible portions 66 and 81. Furthermore, the bending movement of flexible portions 66 and 81 are assisted, and a smooth, flexible deflection of gap sealing drag reduc ers 60 and 80 are attained with protective cap 38A providing smooth continuous slid ing movement over any external trailer ribs and all other trailer protuberances. as well as eliminating any possible chafing of elec trical or pneumatic hoses interconnected between the tractor and the trailer. As thoroughly discussed above, in reference to Figures 3-7, any alternative construction for protective cap 38A can be employed as well as any alternative construction of flexible portions 66 and 81.

As shown in Figure 2 and discussed above in reference thereto, gap sealing drag reduc er described overcomes prior art drawbacks by providing a gap sealing structure which is capable of flexible maneuverability and lateral deflection in order to provide for the complete maneuverability of the tractor with respect to the trailer. As tractor 2 pivots with respect to trailer 1 about the fifth wheel or pivot point 35. Generally, it has been found that in order to provide a sufficient turning radius for tractor 2, the gap sealing drag reducers must incorporate a flexible portion having at least a 30 inch width. Although wider flexible members can be employed, it has been found that a 30 inch wide flexible member will be sufficient for use in any tractor-trailer combination regardless of the size of the gap between the tractor and the trailer.

By referring to Figures 13 and 14, the variations in construction and the general positioning of gap sealing drag reducer 80 can best be understood. In Figure 13, a gap of substantially 48 inches is shown with gap sealing drag reducer 80 mounted therein.

With any gap size up to about 48 inches, gap sealing drag reducer 80 need only comprise the substantially vertical support member 82 and the 30 inch wide flexible member 81.

As mentioned above, an 18 inch open area extending from the rear of the tractor to the leading edge of the gap sealing drag reducer has been found to only slightly affect the efficiency of the gap sealing drag reducer. Consequently, as shown in Figure 13, gap sealing drag reducer 80 is mounted with an 18 inch open area extending from the rear surface of trailer 2 to the forward edge of support member 82. Clearly, in any gap size smaller than 48 inches, the same construction would be employed with vertical support member 82 being mounted to chassis frame rail 75 at a position closer to the rear surface of tractor 2. In this way, the 30 inch turning radius required for the free pivoting movement of tractor 2 with respect to trailer 1 would be consistently achieved with the same drag reducer construction.

In Figure 14, gap sealing drag reducer 80 is shown mounted in a gap of about 60 inches. As shown therein, this embodiment of gap sealing drag reducer 80 comprises the 30 inch wide flexible portion 81 securely mounted to vertical upstanding support member 82. However, since this construction alone would leave an open distance of about 30 inches between tractor 2 and support strut 82, this embodiment also incorporates an additional forwardly extending gap sealing member 83, which is also securely mounted to vertical support member 82. In this way, an effective gap sealing drag reducer of 42 inches is achieved, leaving only about 18 inches of the gap which is not closed.

Of course, any desired dimension can be employed for extension portion 83, as well as any type of material. Since forwardly extending portion 83 does not flexibly move as the tractor-trailer is arcuately pivoted, extension portion 83 can comprise a solid member. However, it has been found that employing the same material as employed for flexible member 81 provides ease of assembly, as well as reduces the expense inherent in carrying additional stock items.

Furthermore, as would be clear to one skilled in the art, any width can be used for extension portion 83 in order to assure maximum open gap of about 18 inches.

However, it has been found that in order to reduce unnecessary stock and maintain a simple catalogue of sizes, specifically sized extension portions 83 are employed for groups of gap widths. Furthermore, flexible member 81 can incorporate a width of about 36 or 40 inches. In this way, gap sealing drag reducers of this invention can be used in gaps ranging up to 100 inches.

As would be clear to one skilled in the art, flexible member 81 and extension portion 83 can comprise a single sheet of flexible material secured to support member 82 at the desired position. Alternatively, flexible member 81 and extension portions 83 can comprise separate, independent units of similar or completely different materials, with both members independently mounted to vertical support member 82. Any variety of these constructions can be used without, in any way, departing from the scope of this invention and without, in any way, affecting the performance characteristics of gap sealing drag reducer 80.

In Figure 15, an alternative construction of gap sealing drag reducer 80 of this invention is shown. In this construction, flexible portion 81 is mounted to vertical support member 82 with pivot means and discussed in detail in reference to Figure 19.

As shown in Figure 15, flexible member 81 would preferably be supportingly held by mounting plates 62 and 63 with the pivot means mounted between the cooperating edges of support member 82 and mounting plate 62.

With this construction, gap sealing drag reducer 80 could be employed for both conventional trailers, with flexible member 81 being pivoted and held in its elongated, gap sealing position, and then quickly folded into the position shown in Figure 15 for connection of the tractor 2 with a trailer 1 having a refrigeration unit 76 extending therefrom. In this folded position, flexible member 81 would substantially seal the remaining gap, thereby assuring complete effective operation of the gap sealing drag reducer 80 as the tractor and refrigerated trailer combination move through a fluid.

Although various alternative embodiments for the gap sealing drag reducer of the present invention have been thoroughly discussed and described in this specification, it should be clear that a gap sealing drag reducer may incorporate any one of a number of the features disclosed and described in this specification without departing from the scope of this invention.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above product without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

WHAT WE CLAIM IS: 1. A modification of a drag reducer as claimed in claim 1 of British Patent Specification No. 1,544,478 wherein said gap sealing means are adapted to be mounted such that the forward edge is, in use, in juxtaposed spaced relationship to said rear panel of the leading element.

2. A drag reducer as claimed in claim 1, wherein said gap sealing means further comprises stiffening ribs for assuring a proper mix of rigidity and flexibility.

3. A drag reducer as claimed in claim 1 or claim 2, wherein the gap sealing means is adapted to be mounted substantially along the central rearwardly extending vertical plane of the gawp.

4. A drag reducer as claimed in any one of the preceding claims, wherein said gap sealing means comprises a flexible portion and a rigid portion.

5. A drag reducer as claimed in claim 4, wherein said flexible portion has a first edge in engagement with a first edge of the rigid member, and a second edge of the flexible member is adapted to be mounted in spaced juxtaposed relationship with the leading panel of the trailing element.

6. A drag reducer a claimed in claim 5, wherein said flexible portion is hingedly engaged with the rigid member.

7. A drag reducer as claimed in any one of claims 4, 5, or 6, wherein t

Claims (27)

**WARNING** start of CLMS field may overlap end of DESC **. employing the same material as employed for flexible member 81 provides ease of assembly, as well as reduces the expense inherent in carrying additional stock items. Furthermore, as would be clear to one skilled in the art, any width can be used for extension portion 83 in order to assure maximum open gap of about 18 inches. However, it has been found that in order to reduce unnecessary stock and maintain a simple catalogue of sizes, specifically sized extension portions 83 are employed for groups of gap widths. Furthermore, flexible member 81 can incorporate a width of about 36 or 40 inches. In this way, gap sealing drag reducers of this invention can be used in gaps ranging up to 100 inches. As would be clear to one skilled in the art, flexible member 81 and extension portion 83 can comprise a single sheet of flexible material secured to support member 82 at the desired position. Alternatively, flexible member 81 and extension portions 83 can comprise separate, independent units of similar or completely different materials, with both members independently mounted to vertical support member 82. Any variety of these constructions can be used without, in any way, departing from the scope of this invention and without, in any way, affecting the performance characteristics of gap sealing drag reducer 80. In Figure 15, an alternative construction of gap sealing drag reducer 80 of this invention is shown. In this construction, flexible portion 81 is mounted to vertical support member 82 with pivot means and discussed in detail in reference to Figure 19. As shown in Figure 15, flexible member 81 would preferably be supportingly held by mounting plates 62 and 63 with the pivot means mounted between the cooperating edges of support member 82 and mounting plate 62. With this construction, gap sealing drag reducer 80 could be employed for both conventional trailers, with flexible member 81 being pivoted and held in its elongated, gap sealing position, and then quickly folded into the position shown in Figure 15 for connection of the tractor 2 with a trailer 1 having a refrigeration unit 76 extending therefrom. In this folded position, flexible member 81 would substantially seal the remaining gap, thereby assuring complete effective operation of the gap sealing drag reducer 80 as the tractor and refrigerated trailer combination move through a fluid. Although various alternative embodiments for the gap sealing drag reducer of the present invention have been thoroughly discussed and described in this specification, it should be clear that a gap sealing drag reducer may incorporate any one of a number of the features disclosed and described in this specification without departing from the scope of this invention. It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above product without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. WHAT WE CLAIM IS:

1. A modification of a drag reducer as claimed in claim 1 of British Patent Specification No. 1,544,478 wherein said gap sealing means are adapted to be mounted such that the forward edge is, in use, in juxtaposed spaced relationship to said rear panel of the leading element.

2. A drag reducer as claimed in claim 1, wherein said gap sealing means further comprises stiffening ribs for assuring a proper mix of rigidity and flexibility.

3. A drag reducer as claimed in claim 1 or claim 2, wherein the gap sealing means is adapted to be mounted substantially along the central rearwardly extending vertical plane of the gawp.

4. A drag reducer as claimed in any one of the preceding claims, wherein said gap sealing means comprises a flexible portion and a rigid portion.

5. A drag reducer as claimed in claim 4, wherein said flexible portion has a first edge in engagement with a first edge of the rigid member, and a second edge of the flexible member is adapted to be mounted in spaced juxtaposed relationship with the leading panel of the trailing element.

6. A drag reducer a claimed in claim 5, wherein said flexible portion is hingedly engaged with the rigid member.

7. A drag reducer as claimed in any one of claims 4, 5, or 6, wherein the rigid member comprises a flat plate which in use is substantially vertically disposed.

8. A drag reducer as claimed in any one of claims 4, 5, or 6, wherein the rigid member comprises a support strut which in use is vertically mounted.

9. A drag reducer as claimed in claim 1, wherein said gap sealing means comprise a rigid portion adapted to be mounted in spaced relationship with the rear panel of the leading element; and a flexible portion coupled with the rigid portion, and extending therefrom in use substantially to the leading panel of the trailing element with the rear edge of the flexible portion in juxtaposed spaced relationship with the leading panel so as to be laterally movable with respect to said leading panel.

10. A drag reducer as claimed in claim 9, wherein at least a portion of said gap

sealing means is capable of pivotal movement about a vertical axis.

11. A drag reducer as claimed in claim 9 or claim 10, wherein said gap sealing member further comprises spring means mounted to said rigid portion and extending along a portion of said flexible portion, thereby imparting greater rigidity and stability to said flexible portion.

12. A drag reducer as claimed in any one of claims 9 to 11, wherein the flexible portion is hingedly mounted to the rigid portion, thereby providing a first extended position for cooperative drag reducing association with a conventional trailer, and a second, folded position for cooperative drag reducing association with a refrigerated trailer.

13. A drag reducer as claimed in claim 12, wherein said gap sealing means includes locking means mounted between the rigid portion and the flexible portion to maintain the hingedly mounted flexible portion securely locked in at least one of its two positions.

14. A drag reducer as claimed in claim 13, wherein said locking means also incorporates quick disconnect means for rapidly engaging and disengaging the locking means.

15. A drag reducer as claimed in any one of claims 12 to 14, wherein the gap sealing means further comprises securement apparatus having a first member mounted to the flexible portion and a second member cooperatively connectable with the first member and mountable on said rear panel of the leading element, thereby assuring secure maintenance of the flexible portion in the second, folded position.

16. A drag reducer as claimed in any one of the preceding claims wherein in use the forward edge of the gap sealing means is spaced away in use from the rear panel of the leading element by a distance no greater than 18 inches.

17. A drag reducer as claimed in claim 16, wherein said flexible portion is mounted on a supporting strut at a position between the two vertical edges thereof, thereby providing a forward leading edge of the flexible member spaced forward of the supporting strut with the rear edge of the flexible member spaced rearwardly of the supporting strut so as to be, in use, in juxtaposed spaced relationship to the leading panel of the trailing element.

18. A drag reducer as claimed in claim 9, wherein said flexible portion has a width of at least 30 inches.

19. A drag reducer as claimed in any one of claims 9 to 18, wherein said gap sealing means includes protection discs mounted along the exposed edge of the flexible portion and positioned for noninjurious sliding engagement with the leading panel of the trailing element during deflective movement of said flexible portion when the gap sealing means is mounted.

20. A drag reducer as claimed in claim 9, wherein said flexible portion has an enlarged cross-sectional area adjacent the interconnection zone between the flexible portion and the rigid portion, thereby assuring greater rigidity and stability of the flexible member when exposed to wind forces during use, while still providing lateral movability and pivotal articulation when directly contacted with the leading panel of the trailing element.

21. A drag reducer as claimed in claim 20, wherein said flexible portion has a substantially solid cross-sectional area.

22. A drag reducer as claimed in claim 21, wherein said flexible portion has a tapered configuration with the distance between the sides of the flexible portion decreasing towards the second edge of the flexible portion.

23. A drag reducer as claimed in claim 9, wherein the terminating end of the flexible portion adjacent the second edge has an enlarged, rounded cross-sectional area.

24. A drag reducer substantially as hereinbefore described with reference to Figures 1 or 2.

25. A drag reducer substantially as hereinbefore described with reference to any one of Figures 3 to 8.

26. A drag reducer substantially as hereinbefore described with reference to Figures 9 to 11.

27. A drag reducer substantially as hereinbefore described with reference to Figures 12 to 15.