Rackets for tennis and other games

A racket for tennis and other similar games, comprising a sensibly oval or pear-shaped stringing surface and an auxiliary element for maintaining the strings in a median plane at determined places, in which at least some strings are wound simultaneously around the frame and around the said auxiliary element.

BACKGROUND OF THE INVENTION 
The present invention concerns a racket for tennis and similar games as 
badminton, squash, etc. . . . 
In classical rackets, the "main" and "cross" strings making the stringing 
pass through holes pierced in the frame which bears directly the tension 
of the strings. 
The use of stringing by holes has noticeable drawbacks, the foremost being 
a reduction of the strength of the frame, specially in the region 
generally called "heart", joining the handle to the strung part of the 
frame. When this heart includes a brace, it is the holes pierced near the 
ends of this brace which are generally the cause of breaks. Besides, the 
strings bear on the edges of the holes and they are cut and broken easily, 
specially when the frame is made of metal tubing. 
These drawbacks have been lessened by placing in the holes of the frame of 
the racket small plastic tubes protecting the strings from the contact 
with the edges of the holes. Unfortunately this solution leads to enlarge 
the holes which increases the possibility of frame breakage, specially, as 
it has been said above, in the "heart". 
PRIOR ART 
A solution, entirely different of the problem of attaching strings, has 
been proposed in U.S. Pat. No. 3,086,777. According to this patent, the 
strings are attached to the crenellations or teeth of an auxiliary 
element, itself attached to the frame. This auxiliary element achieves two 
functions: maintaining of the strings in the median plane of the frame and 
bearing the tension of the strings. 
However, in this patent, this element or "crown" bears all the tension of 
the strings and it must then be strong and be made with steel wire of 
great resistance. It weighs about 20 g. This crown must itself be attached 
to the frame with a steel wire strong enough to resist the tension of the 
strings. Practically, the weight of the string wire used to attach the 
said crown on to the frame is more than 25 g. 
OBJECTS OF THE INVENTION 
The present invention has for object a racket, also including one or 
several auxiliary elements for the stringing, in which are eliminated or 
reduced the holes, a source of weakness in the frame, and the weight of 
the auxiliary elements and of the means used to tie them to the frame. 
Another object of the present invention is to increase the resiliency of 
the stringing, particularly near the frame, specially in the region of the 
heart, and to obtain an excellent response of the stringing at impact of 
the ball on a surface noticeably more extended than with a frame of the 
same size by the means previously used. 
According to the present invention, the tennis racket is characterised in 
the fact that certain at least of the strings surround at the same time 
the frame and the said auxiliary element which they retain against the 
inner periphery of the frame. 
Thus, the steel wire which was used to tie the auxiliary element to the 
frame is eliminated at least in part thus reducing noticeably the total 
weight of the racket.

DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 shows a racket of a known type and now available on the market. 
Within the oval of frame C comprising a main brace E and a secondary brace 
E1 welded or brazed to the frame is placed a crenellated crown Cr, the 
"main" M and the "cross" T strings being attached on the crown, itself 
strongly fastened on the frame C by a steel wire F. In FIG. 1, one sees 
that because of the small distance separating the braces which prevents 
the passing of the tool usually employed for placing the wire attaching 
the crown to the frame, the manufacturer has been led to attach the part 
of the crown Cr in contact with the brace E by a steel wire F1 which is 
independent of the steel wire F used to fasten the crown on the frame 
itself, thus complicating the construction of the racket. 
Thanks to the invention, wire F1 may be eliminted as shown on the FIG. 2 by 
attaching directly the "main" M in the center of the racket to the brace 
E. In FIG. 2 the auxiliary element may be either a complete crown bearing 
the reference Cr or a part of the crown limited to the region of the heart 
bearing the reference 1. 
FIG. 3 represents the passing of mains M42 and M51 of FIG. 2 through the 
spaces comprised between the crown Cr and the frame. According to the 
invention, the turn TO is made around both the brace E and the crown Cr. 
This crown is, under these conditions, sufficiently maintained against the 
brace because it does not have to resist the full pull of the main in this 
region of the "heart", but only to maintain the strings in the plane of 
the stringing at determined positions. 
FIG. 6 represents another solution differing from the preceding one only by 
passing "main" M42 and M51 strings spirally around the sides of the teeth 
of the crown, but without changing the conditions by which the crown Cr is 
maintained against the brace still by winding the strings around both the 
brace and said crown. 
It is thus possible to achieve one of the objects of the invention locally 
with a saving of weight corresponding to the difference between the weight 
of the length of steel wire F1 which is eliminated, and the very small 
weight of the length of the strings passing around the brace E and the 
auxiliary element 1. The additional length of the strings advantageously 
increases the resiliency of the stringing in the region close to the frame 
near the brace, which is very useful and very clearly felt in play tests, 
when the ball is struck far from the center, near the brace. 
The racket which is represented in FIG. 4 is entirely strung accordingly to 
the present invention, thanks to an auxiliary element 1 forming an annular 
crown represented in FIG. 5. This crown is simple and easier to make than 
crowns such as the one which is indicated by the reference Cr in FIG. 1. 
In FIG. 5, crown 1 comprises U-shaped teeth D similar to each other, 
opening towards the frame and interconnected by substantially straight 
lengths of wire which abut the inside of the oval part of the frame of a 
racket in which the crown is installed. In the FIG. 4, the steel wire 
corresponding to F in FIG. 1 used to attach the crenellated crown to the 
frame has been entirely eliminated which results in a reduction in weight. 
Since the crown is not required to bear the full tension of the strings, 
which are fastened to the frame, an additional saving in weight can be 
made by forming the crown of a lightweight alloy of titanium or aluminium, 
while the increased lengths of the strings necessary for passing around 
the frame and the crown only represent a minimum weight. 
Thus the saving of weight becomes very noticeable and exceeds half of the 
45 g. necessary for the crown and the attaching wire of a racket such as 
the one which is represented in FIG. 1. 
It then becomes possible to make frames stronger and stiffer, for example 
by increasing slightly the thickness of the wall of the tube of which they 
are made or to make more easily lighter frames or frames with larger 
stringing surfaces. In play, the racket of the invention achieves results 
which would only be possible with a larger stringing surface, thanks to 
the increased resiliency produced by the passing of all the strings around 
the frame which increases their useful length. 
Another important advantage of the invention is that the angles of the 
curves of the strings around the frame and at the contact points with the 
annular element are greater than in the case of previously known rackets. 
It then becomes possible to increase the tension of the strings and/or to 
use very thin natural gut with very reduced risks of breaks at attaching 
points. 
The FIGS. 7, 8 and 9 represent at enlarged scale several methods of 
wrapping the strings around the crown and the frame in the region of 
points 7, 8 and 9 of the FIG. 4. In FIG. 9, one sees for example that the 
main M81 passes on one side of the crown 1 and through the space defined 
by the crown 1 and the brace E before passing behind the brace and around 
it and the crown 1 as TO, on the left of the teeth, then returns in front 
of the brace before returning through the teeth in passing on the other 
side of the crown 1 to constitute the second string of the double main 82. 
Details at enlarged scale of another type of crown or auxiliary element 
are represented in FIGS. 10, 11 and 12, this crown differing from the one 
shown in the FIG. 5 in the fact that the U-shaped teeth are replaced by 
loops or small circles 1a, the strings passing through holes created by 
these loops and, according to the invention, around the crown 1b and the 
frame C or its brace E to maintain the said crown against the said frame 
or the said brace. 
The racket shown in FIG. 13 is partly strung through holes. However in all 
the region of the heart, including the brace, there are no holes in the 
frame for the stringing and the stringing is achieved by means of an 
auxiliary element 1 comprising teeth of the type previously described and 
shown in FIG. 5. 
In the embodiment of FIG. 13, some of the advantages supplied by the 
invention are even more important than those mentioned about the 
embodiment shown in the FIG. 4; the saving of weight is greater and the 
opportunity to increase the durability or stiffness of the frame or to 
make easily lighter rackets or rackets with large stringing surfaces is 
increased. 
FIG. 14 shows, without its "cross" strings, which are identical to those of 
FIG. 13, a racket mostly strung through holes pierced in the frame, but 
also with the help of two small auxiliary elements 1b in the regions close 
to the ends of the brace E. 
These auxiliary elements 1b comprise holes created in the center of loops 
such as those shown in FIGS. 11 and 12 which require a length of metal 
wire slightly greater than the teeth of element 1 of FIG. 13 but because 
of their small length these elements have however a reduced total weight 
(for example less than 6 g. in steel and less than 4 g. in titanium 
alloy). 
As seen in FIGS. 15 and 16, representing at enlarged scale the circled 
regions of the FIG. 14, these loops offer several advantages. The loops 
are not exactly formed in the median plane of the stringing, but are 
characterised by a small inclination in relation to this median plane, 
tending to place the strings going through the loops slightly better in 
the said plane and also increasing advantageously the length of their 
contact with the loops. 
In other variations of the invention, it is possible to attach all the 
"main" strings, including those attached by holes in FIG. 14, with the 
help on a single auxiliary element replacing the one represented in FIG. 
14, but comprising only loops as those of the element 1b of the FIG. 14, 
or even with the help of an element comprising teeth as those of FIG. 13 
in the middle and loops as those of the FIG. 14 at its ends. 
With these embodiments, one obtains an important saving in weight in 
comparison with a racket of the type represented in FIG. 1 and there is 
not any hole liable to weaken the frame "under" the brace, i.e., between 
this brace and the handle, not just "above" the brace, i.e. in the regions 
where breaks by strain most often occur. 
Besides, these embodiments increase noticeably the resiliency in the region 
of the stringing near the heart where this increase is precisely the most 
advantageous. 
The increase in resiliency occurs in all cases, as indicated above, because 
of the increase of the length of the strings passing around the frame or 
the brace, but also, in the case of loops like those of the FIGS. 14, 15 
and 16, made of resilient metal wire, because of the torsion effect 
exerted upon the loops following the arrows F1 and F2 of the FIG. 16 and 
of the resilient resistance of the loops to this torsion effect. 
The embodiments of the invention which have just been described or 
represented are only given as examples. With crowns analogous to the one 
shown in FIG. 5, it is possible to attach "cross" strings in the manner of 
the "main" strings of FIG. 4 with a passing around the crown and the frame 
as indicated on FIG. 9, or to attach the central main strings according to 
the method represented for the "cross" strings of the FIG. 4. 
However the mode of attaching used for instance for the "main" strings of 
the FIG. 4 is specially interesting as it permits counterbalancing 
immediately, during the stringing, the pressures exerted perpendicularly 
to the stringing upon the auxiliary elements and adapts itself very well 
to a possible protection of these "main" at the end of the frame opposed 
to the handle, for instance by a spiral winding around the frame of a 
light but abrasion resistant strip, covering the parts of the strings 
passing on the outside of the end of the frame. 
The stringing modes described can be easily achieved after some training 
with the help of most of the existing stringing machines, the easy gliding 
of the strings around the different types of auxiliary elements and around 
the frame or the brace permitting the creation of specially high tensions 
without risk of breakages. 
It is interesting to note on all of FIGS. 3, 6, 7, 8, 9, 10, 11, 12 that 
two strings passing around the sides of the same teeth or through the 
space formed between a tooth and the frame or by a loop or through two 
adjacent teeth or loops, bear on opposite sides of the auxiliary element 
in order to balance the pressures exerted by the said strings upon the 
said auxiliary element, which permits limiting the weight and the 
stiffness of the said element. 
In the embodiments represented by the FIGS. 2, 13 and 14, each tooth or 
loop is crossed by two strings passing respectively through the said tooth 
or loop, in opposite directions with two pressures exerted upon the 
opposite sides of the auxiliary element which balance themselves. 
Concerning the FIG. 4, some teeth are crossed only by a single string, but 
in this case the two nearest teeth are each crossed by strings, one at 
least for each one of these adjacent teeth, passing upon the side of the 
auxiliary element opposite to the side upon which passes the single 
string, which compensates, at least partly, the pressure exerted upon only 
a side of the crown by the single string. 
The auxiliary elements described and represented in the previous 
embodiments of the invention are made of metal wire with a diameter for 
instance less than 2 mm. 
But it is possible to use elements made of plastic material, for instance 
ABS or high resistance polyamides. 
The FIG. 17 represents, from the same angle as the FIG. 15, part of an 
element 1c which may replace the elements 1b. The holes of this molded 
element replace those created in the center of the loops of the element 
1b. Practically, the element 1c is made of a group of rings A with a 
section slightly above 2 mm and of a thin strip applying to the inside of 
the oval of the frame replacing the straight parts of the elements 1b and 
tying these rings together. 
As the loops of the elements 1b, these rings are advantageously inclined in 
relation to the median plane of the stringing. 
A non negligible result may be obtained according to the invention with 
elements made only with a simple ring, as shown on FIG. 15 preferably in 
plastic material, permitting for instance the attachment without holes in 
the frame of the "main" M41 and M42 and M91 and M92 for which the position 
of these holes presents the most drawbacks with a racket comprising a 
brace. 
It is evident that changes may be brought to the modes of embodiments which 
have been described, notably by substitution of equivalent technical means 
limiting the scope of the present invention for this reason.