Method for fixing a mud flap to a motor vehicle, a mud flap and a device for performing the method

A mud flap member with a main flap body and an adapter protrusion extending from the upper end of the main flap body is fixed to a motor vehicle body by a portion of its adapter protrusion in such a way that between the motor vehicle body and the adapter protrusion gaps are formed which are too large to substantially retain water therein by capillary action. These gaps are created by providing projections on the surface of that portion of the adapter protrusion in contact with the motor vehicle body or interposing a spacer having such projections between the mud flap and the motor vehicle body.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a method for fixing a mud flap to a motor 
vehicle. More particularly, this invention relates to a method for fixing 
a mud flap, comprising a main flap body and an adapter protrusion 
extending from the upper end of the main flap body, to a motor vehicle 
wherein the mud flap is screwed or clamped to the vehicle body so that at 
least part of the adapter protrusion and, optionally, part of the main 
flap part engages the motor vehicle body. 
2. Description of the Prior Art 
Such mud flaps are known (British Pat. No. 2,037,679 corresponding to U.S. 
Pat. No. 4,315,634) and are widely used both as front wheel and rear wheel 
mud flaps. Generally, such mud flaps are fixed in such a way that the 
inner marginal area of the adapter protrusion, i.e. the area which is 
adjacent to the adapter protrusion edge and located opposite the common 
outer edge of the main flap body and the adapter protrusion, is engaged 
with the fender fold of a motor vehicle. The fender fold, as is 
well-known, being the in-turned edge of a motor vehicle at the mudguard or 
fender. The mud flap is oriented in this position and is then fixed to the 
vehicle, for example, with clamps engaging around the fender fold and the 
marginal area of the adapter protrusion or with screws penetrate the 
marginal area and screwed into the fender fold. This marginal area of the 
adapter protrusion can be bent somewhat out of the plane of the main flap 
body and the remainder of the adapter protrusion, in order to bring about 
a compensation to the fold slope, and/or the inner marginal area of the 
adapter protrusion can be provided with a bendable reinforcing plate 
extending up to the main flap body (as known from British Pat. No. 
1,442,226 corresponding U.S. Pat. No. 3,953,053), in order to permit a 
subsequent orientation of the fitted mud flap. 
When fitting such mud flaps to motor vehicles, a surface of the mud flap, 
conventionally a surface formed by the inner marginal area of the adapter 
protrusion, engages with the vehicle body at the fender fold and is 
pressed by clamps or screws against the vehicle body. Due to this flat 
engagement, which is obviously not ideally flat, between the adapter 
protrusion surface and the adjacent vehicle body, small gaps exist in 
which water can collect. Due to the dimensions of these gaps and the 
resulting capillary forces, the water can be kept in said gaps and can be 
sucked into adjacent, even smaller gaps. These moisture deposits are not 
removed by the slipstream in dry weather and instead only gradually 
disappear due to evaporation. Thus, such moisture deposits lead to 
corrosion of the vehicle body. 
Due to the engagement of part of the mud flap member on the vehicle body, 
discolorations to adjacent body areas can occur, because plasticizer 
migrates out of the mud flap material, which generally is rubber or a 
plastic. When choosing the mud flap material, it is necessary to take 
account of the fact that such plasticizer migrations must be prevented to 
the greatest possible extent, i.e. a relatively high-quality material must 
be used for the manufacture of the mud flaps. 
In another known mud flap with a main flap body and an adapter protrusion 
(British published application No. 2,042,619 corresponding to U.S. Pat. 
No. 4,323,262), roughened portions are provided on the inner marginal area 
of the adapter protrusion engaged with the fender fold to give the mud 
flap a better hold on the latter. These roughened portions are naturally 
relatively flat, so that on engaging the fender fold gaps form between the 
surface of the adapter protrusion and the fender fold, which have such a 
limited height that considerable capillary forces act on the entering 
water, so that the water is generally held even more "firmly" between the 
adapter protrusion and the vehicle body and, consequently, more "firmly" 
in contact with the latter than in the case of the previously described 
mud flaps with a smooth surface. In the case of such mud flaps there is 
still a risk of plasticizer migration onto the vehicle body. 
SUMMARY OF THE INVENTION 
The object of the present invention is to avoid water deposits between mud 
flaps and the vehicle body, whilst reducing the risk of plasticizer 
migration onto the latter. 
To solve the problem of water deposition, a method has been developed 
wherein projections are provided between the actual engagement area of the 
adapter protrusion and, optionally, the main flap body and the vehicle 
body. These projections cause the formation of gaps between the vehicle 
body and the mud flap, when assembled. The projections are of such a 
height and so spaced apart that the gaps so-formed are too large to 
substantially retain water therein by capillary action. 
A mud flap, with such projections provided thereon; and a device, with such 
projections provided thereon, for adapting a conventional mud flap to such 
use have also been developed to effectuate the method.

DETAILED DESCRIPTION OF THE INVENTION 
The fitting of a mud flap to a vehicle body, e.g., the engagement of the 
inner marginal area on the fender fold whilst interposing such projections 
results in that only the latter are in contact with the vehicle body, 
whilst the adjacent surface area of the mud flap is, due to the height of 
the projections, at such a distance from the body, that water entering the 
space between the latter and the mud flap immediately, flows away, i.e. is 
not held by capillary action. In addition, due to the dimensioning of this 
spacing, dirt deposits in this area are removed by the outflowing water. 
When traveling, air flows through the gaps formed by the spacing and 
brings about a rapid drying. 
It should be noted that the maximum height of the projections used is 
substantially determined by the strength of the mud flap material and by 
the desired optical impression, because on the one hand a deformation of 
the mud flap in the area between the projections is to be avoided and 
because on the other hand the distance between the vehicle body and the 
mud flap must not be sufficiently large that the observer will look upon 
it as unattractive. Preferably, the projections are of a height of at 
least 0.5 mm and, most preferably, of a height of 1 to 3 mm. Obviously, 
the distance between adjacent projections must be large enough to ensure 
that no capillary spaces are formed, i.e. the distance is at least as 
large as the height of the projections, but is preferably between 5 and 15 
mm. 
Due to the fact that contact with the vehicle body only takes place via the 
projections, the plasticizer migration is also reduced, whereas in the 
case of known mud flap attachments this can take place over a large 
engagement surface area. 
For performing the method according to the invention, a mud flap can be 
used which, on the inner marginal area of the adapter protrusion, in the 
fitted state, has spaced projections, whose height is preferably 0.5 mm 
and most preferably 1 to 3 mm. The projections can be constructed in one 
piece with the mud flap. 
Preferably, the projections are in the form of ribs, so that said ribs form 
guidance surfaces for the downward draining away of the entering water in 
the direction of the main flap body. For this purpose, therefore, one end 
of each rib can be nearer to the main flap body than the other end of the 
rib, i.e. with the mud flap fitted the rib passes upwards or slopes 
upwards from one end. 
In order to obtain a minimum contact surface between the ribs and the 
vehicle body, the width of the ribs can decrease on increasing height from 
the adapter protrusion surface, so that there are only very small contact 
surfaces and consequently moisture is only held to a very limited extent 
between the ribs and the vehicle body. 
Mud flaps are also known, in which an elongated engagement or contact lip 
is fitted at a distance from the inner edge of the adapter protrusion in 
the assembled state, said lip inclined towards the surface of the adapter 
protrusion and in the direction of the inner edge. With the mud flap 
fitted, this engagement lip engages on the outer surface of the vehicle 
body and consequently forms an optical transition from the mud flap to the 
vehicle body. 
In the case of such a mud flap, there is a particularly high risk of water 
depositing between the engagement lip and the vehicle body and in order to 
prevent such water deposits, the engagement lip face facing the adapter 
protrusion surface can be provided with projections having a height of at 
least 0.5 mm and preferably 1 to 3 mm. The engagement lip preferably has 
apertures therethrough adjacent to the adapter protrusion surface. 
As a result of the projections, the same advantages are obtained for the 
area between the engagement lip and the vehicle body as through the 
projections positioned between the inner marginal area of the adapter 
protrusion and the vehicle body, particularly the fender fold. The water 
entering the area between the engagement lip and the vehicle body which is 
no longer retained by capillary forces, can either flow out at the bottom 
of the engagement lip or through the apertures provided in the latter. 
The projections provided between the engagement lip and the vehicle body 
preferably comprise ribs extending between the adapter protrusion surface 
and the free edge of the engagement lip. At least one aperture is provided 
between adjacent ribs. The use of ribs ensures a favorable guidance of the 
water to the openings. The projections and/or ribs are preferably 
constructed in one piece with the engagement lip. 
If a conventional mud flap is to be fitted according to the method 
according to the invention, without making changes to the mud flap, it is 
also possible to use an elongated spacer or connecting piece having 
projections substantially extending from the face of the spacer which will 
contact the vehicle body and which preferably have a height of at least 
0.5 mm and most preferably 1 to 3 mm, said projections preferably being 
formed by first ribs. 
During assembly, such a spacer can be arranged between the area of the mud 
flap, e.g., the inner marginal area of the adapter protrusion, which 
engages on the vehicle body, e.g., the fender fold and the actual vehicle 
body, so that it is firmly held in the assembled state between the mud 
flap member and the vehicle body. The spacer then leads to the same 
advantages as a correspondingly constructed, aforementioned mud flap. 
In the case of such a spacer, it is also appropriate if the width of the 
first ribs is greater at the base thereof than at the tip, because as a 
result, the contact surface with the vehicle body is reduced. 
For positioning the spacer and for producing an optical transition between 
the mud flap and the vehicle body, an engagement lip can be provided on 
one longitudinal side of the spacer which rises from the face of the 
spacer which will contact the vehicle body, whereby second ribs are 
provided on the surface facing the first ribs and the height thereof is 
preferably at least 0.5 mm and most preferably 1 to 3 mm and between which 
there is at least one aperture extending into the plane of the bases of 
the first ribs. 
The construction and function of such a spacer in the assembled state 
together with the mud flap corresponds to that of a mud flap with an 
engagement lip, as explained hereinbefore. 
The invention is described hereinafter relative to non-limitative 
embodiments and the attached drawings. 
In the represented embodiments, corresponding parts and areas are given the 
same reference numerals. 
The mud flap shown in FIG. 1 has a substantially rectangular main flap body 
1, which is defined by a lower edge 3, an inner lateral edge 5 and an 
outer lateral edge 4. The upper lateral edge 6 and its imaginary extension 
in the direction towards the outer lateral edge 4 forms an upward 
limitation to the main flap body. In the plane of the main flap body 1, 
there is upwardly connected thereto an adapter protrusion 2, whose outer 
edge is formed by the upwards extension of edge 4, whilst its inner edge 7 
slopes upwards and outwards from the upper edge 6 of the main flap body 1. 
The represented side of the mud flap is that which points rearwards in the 
fitted state, i.e. is remote from the wheel. A mud flap in this form is, 
for example, shown in British Pat. No. 2,037,679. In accordance with this 
known mud flap, the mud flap of FIG. 1 also has a bending line 8, i.e. the 
area between line 8 and edge 7 and optionally also part or all the upper 
marginal area of the main flap body are bent somewhat out of the plane of 
the latter and the remainder of the adapter protrusion 2, in order to 
bring about the normal slope of the fender fold and as is also described 
in British Pat. No. 2,037,679. 
In the inner marginal area of the adapter protrusion between bending line 8 
and edge 7 are provided circular projections, whose height is at least 0.5 
mm and is preferably 1 to 3 mm. The distance between the projections is 
approximately 5 to 15 mm. The projections are constructed in one piece 
with the mud flap, which is conventionally made from rubber. 
When assembling the represented mud flap, projections 9 are engaged on the 
fender fold of the motor vehicle, followed by fixing, usually by means of 
clamps, which engage both round the fender fold and the adjacent inner 
marginal area of the adapter protrusion 2 of the mud flap member. Such a 
fixture is shown in British published application No. 2,042,619. 
In the assembled state, the upper surfaces of projections 9 engage with the 
fender fold, whilst the adjacent surface of adapter protrusion 2 is at a 
distance from the fender fold, which is determined by the height of the 
projections 9 and the elasticity thereof, i.e. the distance corresponds to 
the height of the projections in the state pressed against the fender 
fold. However, as the mud flap material is relatively resistant to 
compression, the height of the projections 9 is not significantly reduced 
by the contact pressure, so that there is preferably a spacing of 1 to 3 
mm and the resulting free space between the surface of adapter protrusion 
2 and the fender fold makes it possible for entering water to flow away, 
as well as for air to flow through, which removes existing moisture. 
The mud flap shown in FIG. 2 essentially corresponds to that of FIG. 1, but 
the projections have a differing form, namely that of straight ribs 19, 
whose ends closer to the edge 7 of adapter protrusion 2 are higher than 
the end thereof remote from edge 7. Ribs 19 run parallel to one another 
and are spaced apart by a distance of preferably 5 to 15 mm. Their height 
corresponds to the height of projections 9 in FIG. 1, but their width 
decreases with increasing height, so that the rib surface engaging on the 
fender fold is very narrow. 
In the assembled state, ribs 19 have the same action and function as 
projections 9 in FIG. 1, the represented slope of ribs 19 aiding the 
downward outflow of penetrated water. 
The mud flap according to FIG. 3 corresponds to those of FIGS. 1 and 2. The 
projections are formed by bent ribs 29, so that they have two legs 29' and 
29". The corresponding legs of all the ribs run parallel to one another 
and with a spacing corresponding to that of ribs 19 in FIG. 2. Legs 29" of 
ribs 29 slope in substantially corresponding manner to ribs 19, whilst 
legs 29' are at right angles thereto. 
FIGS. 4 and 5 show a modified mud flap, which has a main flap body defined 
by the inner edge 15 and outer rib 11, as well as the lower edge 13, 
whilst said flap body is bounded at the top by edge 16 and its imaginary 
extension in the direction of rib 11. An adapter protrusion 12 is 
connected at the top to the main flap body 10 in the plane thereof, the 
outer edge of protrusion 12 being formed by rib 11. Ribs 14 slope 
downwards from rib 11. The construction of the mud flap to this extent 
corresponds to the construction of the mud flap of British Pat. No. 
2,037,679 and the represented mud flap surface is that which faces the 
wheel in the assembled state. 
The marginal area of the adapter protrusion 12 opposite to rib 11 is formed 
by a lip 17 bent about line 18 in the direction of the rear face of 
adapter protrusion 12 (FIG. 5), said lip extends into the area of the main 
flap body 10. This lip carries sloping ribs 39, whose height, spacings and 
slope substantially correspond to those of ribs 19 of FIG. 2. The ribs can 
be constructed in one piece with lip 17 and consequently in one piece with 
the mud flap. 
For assembly purposes, the mud flap is positioned in such a way with 
respect to the wheel opening, that ribs 39 engage on the outer face of the 
vehicle body adjacent to the wheel opening and fixing can then take place 
either by screws screwed through the lip and the vehicle body, or by 
struts. Thus, for this purpose, the struts can be fitted on the one hand 
to points in the wheel case and on the other to the mud flap, which for 
this purpose has the openings or penetratable regions indicated in FIG. 4 
through which can be placed attachment screws. In this embodiment, ribs 39 
once again have the same function as described in conjunction with the 
projections of FIG. 1 and the ribs according to FIGS. 2 and 3. 
The mud flap of FIG. 6 is similar to that of FIG. 2, the ribs 49 
corresponding to ribs 19 in FIG. 2. In addition, the mud flap has an 
engagement lip 41 spaced from edge 7 and substantially parallel to the 
latter, said lip being provided on the side of the adapter protrusion 2 
carrying ribs 49 and is constructed in one piece with the mud flap member. 
The distance between engagement lip 41 and edge 7 is greater in the 
connecting area of lip 41 and protrusion 2 than in the area of the free 
edge of lip 41, i.e. the latter slopes in the direction of edge 7. On the 
side of engagement lip 41 facing ribs 49 are formed ribs 44, which extend 
over the entire height of lip 41 and pass at their lower end into a rib 49 
in each case. 
Between two ribs 44, there is an aperture 43 in the engagement lip and this 
extends to the surface of adapter protrusion 2, or in the lower area of 
engagement lip 41, to the surface of the main flap body 1. The boundary 
surface of openings 43 closer to the lower edge 3 of the main flap body 
and emanating from the surface of adapter protrusion 2 or the main flap 
body 1 is aligned with the side walls of ribs 44, 49 at the top in FIG. 6, 
so that water guided by a rib 44 and/or a rib 49 flows directly into and 
through opening 43, i.e. is not held back at a wall portion of engagement 
lip 41 between ribs 44, 49 and the adjacent opening 43. 
It should be noted that ribs 44 and 49 need not be interconnected, and can 
instead end shortly before the transition from engagement lip 41 to 
adapter protrusion 2. In this case, water can also flow away along 
engagement lip 41. 
For the assembly of the mud flap according to FIG. 6, the ribs 49 are 
engaged on the fender fold, engagement lip 41 engaging on the outside of 
the vehicle body. The fixing can then take place in the same way as 
explained in connection with FIG. 1. 
FIG. 7 shows a mud flap corresponding to that of FIG. 1, but without the 
projections in the vicinity of the adapter protrusion. The mud flap is in 
this case shown by dot-dash lines. 
On the mud flap according to FIG. 7 is provided a spacer, which has a 
planar base plate 51, which can be fixed to the mud flap by means (not 
shown) of screws or rivets passed through the bores 52 and 53. In this 
position, base plate 51 passes through the entire inner marginal area of 
adapter protrusion 2, as well as part of the upper marginal area of the 
main flap body 1. 
On the edge of base plate 51 remote from edge 7 of adapter protrusion 2 is 
formed an engagement lip 54, which has openings 55 and which carries ribs 
56 on its side facing edge 7 and said ribs pass into ribs 59 on base plate 
51. Engagement lip 54 corresponds to engagement lip 41 of FIG. 6, ribs 56, 
59 to ribs 44, 49 of FIG. 6. Openings 55 and ribs 56, 59 are associated 
with one another in the same way as in the embodiment according to FIG. 6, 
i.e. the spacer of FIG. 7 after fitting to a mud flap lead to a 
construction, whose function is the same as that of the mud flap of FIG. 
6. 
The spacer shown in FIG. 8 on a mud flap represented in dot-dash form 
corresponding to the mud flap of FIG. 7, corresponds in its basic 
construction to the spacer of FIG. 7, because it has a base plate 61 
corresponding to base plate 51 with ribs 69 corresponding to ribs 59 and 
an engagement lip 64 with opening 65 and rib 66 corresponding to 
engagement lip 54 with openings 55 and ribs 56 of FIG. 7. Ribs 69 taper in 
the same way as ribs 19 in FIG. 2. 
Differing from the spacer according to FIG. 7, the spacer of FIG. 8 is only 
fixed to the mud flap by means of a bore (63) provided in the upper end 
area, so that the position of the fixed spacer can be modified with 
respect to edge 7 of adapter protrusion 2 of the mud flap for adapting to 
different fender fold configurations.