[0001] The invention relates to a device for aligning strings in a racquet, especially in
a tennis or badminton racquet.
[0002] Shot precision in tennis or badminton depends not only on the string tension but
also on the string alignment in a racquet. After every time a ball or a shuttlecock
has been hit with a racquet, the strings move. Eventually the shift is substantial
and hitting a ball or a shuttlecock is no longer precise. A solution that eliminates
this kind of movement of the strings is known from the application description no.
P- 287768 called "Strings, especially for tennis racquets", in which crossing horizontal
and vertical strings are connected at points of junction. In the mentioned solution
there is a problem with adjusting tension in individual strings.
[0003] There is a device known from the French application description no.
FR 90 04878 A1 called "Dispositif pour rétablir l'équidistance entre les cordes du tamis d'une raquette"
that creates equal distances in between racquet strings. This device consists of a
plate with a handle, and attached convex elements, which align racquet strings in
equal distances after they are placed in between the strings.
[0004] There is a string aligning device known from the German description no.
DE 295 05 075 U1 pertaining to the utility model called "Vorrichtung für einem Schläger zum Ausrichten
von verrutschten Saiten" that has a plate with spikes on the top of the plate. The
distances in between the spikes are selected in such a way that the device can bring
the shifted strings back to the original position after the spikes are inserted in
between the strings.
[0005] There is a string aligning device known from the European application description
no.
EP 0 598 482 A2 pertaining to the solution called "Racquet string aligner" that consists of a plate
with protruding elements. The plate is in a ball can cap shape and may be used as
a cover for a typical can for tennis balls.
[0006] In the last three devices described above, regulating the distances between strings
is very time consuming.
[0007] There is also a device known from the American patent description no.
US 5,823,900 A called "Process and device for bringing into alignment the strings of an interlaced
network" that is used to align tennis racquet string along a straight line. In order
to set the strings easily, the device has half-elliptical, half-round or oval plates
attached to a base plate, which impact the strings during their alignment. This device
does not guarantee precise alignment of all strings. In addition, the forces that
cause the strings to align are directed mainly at the points of junction. Because
the strings are deteriorated mostly at these points of junction, the forces created
by this device may cause the strings to break.
[0008] According to the invention, in the device for aligning strings in a racquet comprising
a plate with protrusions narrowing at the end, coming out of a flat top surface of
the plate, the protrusions have such dimensions and shape that they fit spaces in
between the strings of the racquet. Each protrusion has a cuboidal part with a base
sitting on the flat top surface of the plate, whereby the cuboidal part turns upwards
into a truncated pyramidal part with convex walls. It is advantageous that dimensions
of the cuboidal part, which guarantees stable alignment, correspond to the dimensions
of a net window, in which the appropriate protrusion is inserted. According to the
invention the pyramidal part of every protrusion plays only a role of a guide during
the process of inserting the device into net windows or string windows.
[0009] Advantageously, the protrusions are aligned in main rows along lengthwise lines situated
parallel to main strings and in cross rows along crosswise lines situated parallel
to cross strings, while the distance between side surfaces of the cuboidal parts of
the protrusions of two neighboring main and cross rows are not smaller than thickness
of strings. Especially, the distances at protrusion corners between facing side surfaces
of protrusion of two neighboring main rows or cross rows, can be not smaller than
the thickness of strings that means that the distances between facing side surfaces
of protrusion should be from 1.5 mm to 2 mm.
[0010] Height of protrusions can be the same or the protrusions in the middle may be the
tallest, and the rest of the protrusions may be shorter progressively towards edge
of the device.
[0011] Advantageously, edges of protrusions are rounded.
[0012] Advantageously, protrusions are capped by top surfaces with rounded edges.
[0013] Advantageously, the plate has side handles, which are created by grooves with rectangular
rounded through-hole.
[0014] The invention will now be described by way of example and with reference to the accompanying
drawings in which:
Fig. 1 shows perspective view of a device for aligning strings, especially in tennis
and badminton racquets;
Fig. 2 shows the device for aligning strings in a racquet before the protrusions are
placed in between the racquet strings; and
Fig. 3 shows the device for aligning strings in the racquet after placing protrusions
in between the racquet strings.
[0015] A device for aligning strings in a racquet shown in Fig. 1 comprises a plate 10 with
a flat surface 11, from which protrusions 20, 30, 40 and outermost protrusions 50
stick out. The protrusions 20, 30, 40 are positioned on the plate 10 in a way that,
after putting the device together with a racquet 60 shown in Fig. 2 and Fig. 3, in
an ideal situation, the symmetry axis of each and every protrusion aligns with the
middle of a corresponding window 64 of an interlaced net of strings 61 created from
main strings 62 and intersecting with them cross strings 63. In reality, the position
of the protrusions deviates from the ideal situation mentioned above because racquets
differ. In the device shown in Fig. 2, the protrusions are positioned in main rows
18 aligned parallel with main strings, and simultaneously positioned in cross rows
17 aligned parallel with cross strings, and curved diagonal lines. The interlaced
net windows 64 with inserted protrusions meet each other's corners, meaning that after
inserting the protrusions into racquet net windows 64 the protrusions are placed in
every second net window 64 in both: the main rows 18 and the cross rows 17. In the
device shown in Fig. 1, 2 and Fig. 3, the distances at protrusion corners between
facing side surfaces of protrusion of two neighboring main rows or cross rows, are
not smaller than the thickness of strings. Currently, racquet strings are 1.15 mm
to 1.4 mm thick. Therefore, the distances between facing side surfaces of protrusion
should be from 1.5 mm to 2 mm. In case of universal devices, the distances between
facing side surfaces of protrusion of two neighboring columns or rows may be from
1.6 mm to 1.8 mm. Generally, the distances between facing side surfaces of protrusion
of two neighboring columns or rows should be greater than thickness of the strings
by 0.05 mm to 1.0 mm. After the process of aligning strings is complete, the strings
may touch the device top surface 10 or they may be very close to the top surface 10,
from 0.1 to 0.5 mm away.
[0016] Because the greatest density of windows 64 is in the middle of the racquet, the greatest
density of protrusions is also in the middle of the string aligning device. The protrusions
20 with the smallest base are in the middle of the device, and the protrusions 30,
40 with the biggest bases are placed on the outskirts of the device, excluding outermost
protrusions 50, which are in proximity to side handles 12, which are formed by grooves
13 with rectangular rounded through-hole 14. Above mentioned grooves 13 facilitate
separation of the device from a racquet after the process of string alignment is complete.
[0017] The shape of the plate 10 of the device that aligns strings in a racquet corresponds
to a reduced interior hitting surface of a racquet head, inside which there is a net,
called strings. Therefore, the shape of the plate 10 resembles an oval that is cut
creating a straight line edge with a recess 15, which points in the direction of the
racquet handle after the device is placed in the net windows. In Fig. 1, the straight
line edge is parallel to the rows of protrusions. This kind of shape of the device
allows to mount a vibration dampener, which is placed in the center below the last
string, during the string aligning process.
[0018] Since the plate 10 is smaller in size than the interior hitting surface of a racquet
head, it is possible to place the device that aligns strings in a racquet, with tapering
protrusions placed in racquet net windows, even when the strings are shifted and net
windows are distorted. Since the plate 10 is smaller in size than the interior hitting
surface of a racquet head, the device can be moved around enough so after preliminarily
inserting the device into the net windows, there is a possibility of repositioning
the device so all strings get aligned as per racquet manufacturer's recommendation.
The plate 10 has rounded edges 16 to prevent strings from breaking.
[0019] Each and every protrusion 20, 30, 40 and outermost protrusion 50 has a bottom part,
called afterward a cuboidal part, correspondingly 22, 32, 42, 52, which is cuboidal
shape with a rectangular base with rounded corners, and a top or upper part, called
afterward a pyramidal part, correspondingly 21, 31, 41, 51, which is pyramid shape
with rectangular base with rounded corners and convex walls capped by a top surface,
correspondingly 23, 33, 43, 53, that may be flat, convex or concave with dull edges,
for example rounded edges, or a combination of these surfaces. In other words, the
cuboidal part 22, 32, 42, 52 has the base sitting on the flat top surface of the plate
10 and turns upwards into a truncated pyramidal part 21, 31, 41, 51 with convex walls.
The top surface of the pyramid part is designed in a way so the device does not damage
a racquet cover when a tennis racquet is placed in that cover. In one of embodiments,
the protrusions 20, 30, 40, 50 are capped by top surfaces with rounded edges.
[0020] During the string aligning process, forces are equally distributed along the edges
of the protrusion, because every protrusion has a cuboidal part and a pyramidal part
with rounded edges, rectangular base and truncated top. Therefore, this invention
is harmless to strings and guarantees stable alignment because of the cuboid part
of the protrusions.
[0021] Top surfaces of the protrusions are basically at the same level, meaning that in
one of the options the height of all protrusions 20, 30, 40, 50 is the same. The dimensions
of the cuboidal part, which guarantees stable alignment, correspond to the dimensions
of the net window, in which the appropriate protrusion is inserted. The cuboidal part
of every protrusion turns into the truncated pyramidal part with a top surface, correspondingly
23, 33, 43, 53. The pyramidal part of every protrusion plays a role of a guide during
the process of inserting the device into net windows or string windows.
[0022] In another option, the protrusions located in the middle of the device are taller
in order to facilitate the process of inserting the protrusions into string windows
of the racquet. Moving gradually toward the edges of the device, the protrusions get
shorter; therefore the protrusions located on the outskirts of the device are the
shortest.
[0023] Although only the protrusion 40 shows rounded edge 44, the edges of both the bottom
part 22, 32, 42, 52 and the top part 21, 31, 41, 51 of every protrusion correspondingly
20, 30, 40, 50 are rounded, what prevents strings from breaking.
[0024] The device that aligns strings in a racquet may have a handle, which was not shown
on any drawing, that is attached permanently to the plate 10 or a removable handle
with Velcro that may be placed in openings or rectangular rounded through-holes 14
of side handles 12.
[0025] While the present invention has been depicted, described, and is defined by reference
to particular preferred embodiments of the invention, such references in the foregoing
specification do not imply a limitation on the invention. It will, however, be evident
that various modifications and changes may be made thereto without departing from
the broader scope of the invention. The presented preferred embodiments of the invention
are exemplary only, and are not exhaustive of the scope of the invention.
1. A device for aligning strings in a racquet comprising a plate (10) with protrusions
(20, 30, 40, 50) narrowing at the end, coming out of a flat top surface of the plate
(10), whereby the protrusions (20, 30, 40, 50) have such dimensions and shape that
they fit spaces in between the strings of the racquet characterized in that each protrusion (20, 30, 40, 50) has a cuboidal part (22, 32, 42, 52) with a base
sitting on the flat top surface of the plate (10), whereby the cuboidal part (22,
32, 42, 52) turns upwards into a truncated pyramidal part (21, 31, 41, 51) with convex
walls.
2. The device for aligning strings in a racquet according to claim 1, characterised in that the protrusions (20, 30, 40, 50) are aligned in main rows along lengthwise lines
situating parallel to main strings and in cross rows along crosswise lines situating
parallel to cross strings, while the distance between side surfaces of the cuboidal
parts (22, 32, 42, 52) of the protrusions (20, 30, 40, 50) of two neighboring main
and cross rows are not smaller than thickness of strings.
3. The device for aligning strings in a racquet according to claim 1, characterised in that height of protrusions (20, 30, 40, 50) is the same.
4. The device for aligning strings in a racquet according to claim 1, characterised in that the protrusions (20) located in middle of the device are the tallest whereas remaining
protrusions (30, 40, 50) get shorter moving towards edges of the device.
5. The device for aligning strings in a racquet according to claim 1 or 2 or 3 or 4,
characterised in that edges of protrusions (20, 30, 40, 50) are rounded.
6. The device for aligning strings in a racquet according to claim 1 or 2 or 3 or 4 or
5, characterised in that protrusions (20, 30, 40, 50) are capped by top surfaces (23, 33, 43, 53) with rounded
edges.
7. The device for aligning strings in a racquet according to claim 1, characterised in that the plate (10) has side handles (12), which are created by grooves (13) with rectangular
rounded through-hole (14).