US20100162539A1

US20100162539A1 - Assembly including a ratchet device and a tightening strap

Info

Publication number: US20100162539A1
Application number: US12/644,897
Authority: US
Inventors: Henri Rancon
Original assignee: Salomon SAS
Current assignee: Salomon SAS
Priority date: 2008-12-23
Filing date: 2009-12-22
Publication date: 2010-07-01
Also published as: JP2010148881A; FR2940133A1; FR2940133B1; ATE514350T1; EP2201856A1; EP2201856B1

Abstract

An assembly including a ratchet tightening device and a band. The device includes a base, a driving lever, and a pawl. For at least one tooth of a series of serrations of the band, at least one straight line tangent to the meshing surface of the tooth and parallel to the band, forms, together with the longitudinal direction of the band, an angle that is less than 90 degrees. A driving end of the lever is configured to cooperate with the serrations of the band. A retaining zone of the pawl is configured to cooperate with the serrations of the band.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. §119 of French Patent Application No. 08 07414, filed on Dec. 23, 2008, the disclosure of which is hereby incorporated by reference thereto in its entirety.

BACKGROUND

1. Field of the Invention
The invention relates to an assembly including a ratchet tightening device and a strap, as used on clothing or sports articles.
Assemblies of this type are used to reversibly tension elements such as flaps of a shoe or boot, pieces of fabric, or the like.
2. Description of Background and Other Information
An example of an application of the aforementioned field of the invention is that relating to snowboarding. Certain snowboard bindings include one or more straps for removably retaining a boot on a base of the binding.
A strap generally includes a band, a cap, and a ratchet tightening device affixed to the cap. The length of the strap is adjusted by moving the band with respect to the cap using the device. To this end, a lever of the device makes it possible to shorten the strap, the ratchet preventing lengthening when the lever is not actuated. If necessary, the lengthening of the strap, or its opening by separation of the band from the cap, is obtained by actuating the ratchet using a release button. This operation is called for by a user of the device, i.e., a snowboarder who wants either to reduce the tension of the strap, or to release a boot from a binding.
On most straps, the band is provided with serrations, i.e., a successive series of teeth along its length. For this reason, a driving end of the lever has one or more teeth provided to cooperate with the serrations on the band, in order to apply a force on the band in a direction of tightening or shortening the strap. The pawl of the ratchet tightening device also cooperates with the serrations in order to oppose the lengthening or the opening of the strap.
A strap of this type is overall satisfactory during use, in particular for its ease of implementation. However, some disadvantages can be noted.
For example, the serrations wear out over time, in particular in the zone in which tightening of the strap is the strongest. Consequently, the driving end of the lever sometimes does not mesh completely with the serrations of the band, in the sense that a tooth can disengage in the case of the application of a strong tightening force.
A lack of progressiveness in strap tightening can also be noted, such lack of progressiveness increasing as the serrations tend to wear out.
Furthermore, over time, i.e., as wear increases, the amount of energy necessary to cause the tightening also increases. In other words, the tightening of the strap causes more fatigue as it wears out.

SUMMARY

In view of the foregoing, the invention reduces, or even eliminate, wear on the serrations. The invention also optimizes the meshing of the driving end of the lever with the teeth of the band of the strap. The invention also improves upon the progressiveness of tightening of the strap. Finally, the invention improves tightening efficiency.
To this end, the invention provides an assembly including a ratchet tightening device and a band of a strap, the band extending along its length, from a fastening end to a free end, the band comprising a series of teeth, or serrations, the ratchet device including a base, a driving lever, and a pawl, the lever being articulated on the base and including an end for driving the band along a first direction, on the one hand, and a handling end, on the other hand; the pawl being articulated on the base and having a retaining zone provided to oppose the displacement of the band along a second direction opposite the first direction, an elastic mechanism constantly biasing the retaining zone of the pawl towards the base.
At least one tooth of the teeth, or serrations, of the band, in the assembly according to the invention, at least one straight line, tangential to the meshing surface of the tooth and parallel to the band, forms, together with the longitudinal direction of the band, an angle that is less than 90 degrees. In addition, the driving end of the lever is configured to cooperate with the serrations of the band. Further, the retaining zone of the pawl is configured to cooperate with the serrations of the band.
The teeth, or serrations, of the band according to the invention have a longer active portion, for a band having a width equal to a band of the prior art. This means that the active length of a tooth is greater than the width of the band. Consequently, the active surface of the tooth, which is that in contact with the driving end of the lever, is larger than for a tooth of a band of the prior art.
As a result, the contact pressure exerted on a tooth, in particular during tightening of the assembly, is reduced. The reduction is to be considered relative to an assembly provided with a prior art device.
One of the resulting advantages in particular is a substantial reduction of the wear on the teeth, i.e., on the serrations. In the same context, the wear on the driving end of the lever is also reduced. Consequently, the meshing of the driving end of the lever with the teeth of the band is optimized, in the sense that the reduced contact pressure prevents the teeth from disengaging.
Another advantage is related to the shape of the teeth, i.e., the serrations, of the band. Indeed, with reference to a longitudinal extent of the band, at least a portion of a given tooth is transversely level with a portion of a subsequent tooth. This provides a progressive transition of the tightening force exerted by the lever on the band, from one tooth to the next. In other words, tightening is more progressive and requires less effort on the part of the user.
Also, an improvement to tightening efficiency is realized, because the reduced pressures decrease friction of the lever on the band.
As explained below, in certain cases, the ratchet tightening device includes a release button, the base has a first flange and a second flange connected by a bridge, the lever is articulated on the base between the flanges, the first driving direction is substantially parallel to the flanges and to the bridge, the pawl is articulated on the base between the flanges, the elastic mechanism biases the retaining zone of the pawl towards the bridge, and the release button is provided to move the pawl retaining zone away from the bridge, against the action of the elastic mechanism. In a broader manner, the release button is provided to bias the pawl retaining zone against the action of the elastic mechanism.
This arrangement corresponds to a very widespread handling standard, the arrangement having wide-ranging application.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will be better understood from the description that follows, with reference to the annexed drawings illustrating, by way of non limiting embodiments, how the invention can be implemented, and in which:

FIG. 1 is a perspective view of a snowboard binding provided with straps, according to a first embodiment of the invention;

FIG. 2 is a partial side view of a first strap of the binding of FIG. 1;

FIG. 3 is a cross section of the first strap along the line III-III of FIG. 1;

FIG. 4 is a cross section, similar to FIG. 3, in a case in which a tightening device drives a band of the strap;

FIG. 5 is a cross section, similar to FIG. 3, in a case in which the device releases the tension on the band;

FIG. 6 is a partial enlargement of FIG. 1, showing the tightening device in greater particularity, in the figuration by which the device retains the band of the strap;

FIG. 7 is a schematic top view of the band of the first strap, in a configuration in which it is biased by two teeth of a driving lever of the device, and in which a pawl allows the band to move forward;

FIG. 8 is similar to FIG. 7, in a configuration in which the band is biased by a single tooth of the driving lever, and in which the pawl of the device opposes the backward movement of the band;

FIG. 9 is similar to FIG. 3, according to a second embodiment of the invention;

FIG. 10 is a schematic top view of a band of a strap, according to a third embodiment of the invention; and

FIG. 11 is a schematic top view of the band of a strap, according to a fourth embodiment of the invention.

DETAILED DESCRIPTION

Although the description that follows relates to assemblies used in the field of snowboarding, it is to be understood that the invention applies to other fields as mentioned above.
For example, the assembly of the invention, comprising a tightening device, can be used as part of an article of footwear, such as a shoe or boot, for tightening flaps in a manner disclosed in commonly owned U.S. Pat. No. 6,536,138 and U.S. Patent Application Publication No. 2008/0189922, the disclosures of which are hereby incorporated by reference thereto in their entireties. The invention can also be used as part of an article of footwear for tightening the upper on a wearer's foot in a manner disclosed, for example, in commonly owned U.S. Patent Application Publication No. 2009/0119952, the disclosure of which is hereby incorporated by reference thereto in its entirety.
A first embodiment of the invention is described herein with reference to FIGS. 1 to 8.
As shown in FIG. 1, an assembly includes a snowboard binding 1, in the form of a “strap-in” binding, provided to retain a boot on a snowboard 3. Additional examples of such bindings are disclosed in commonly owned U.S. Pat. No. 6,405,457 and U.S. Pat. No. 7,036,830, and U.S. Patent Application Publication No. 2005/0046150, the disclosures of which are hereby incorporated by reference thereto in their entireties.
In a known manner, the binding 1 has a baseplate 4, as well as a lateral edge 5 and a medial edge 6, the lateral and medial edges extending upwardly from the baseplate, the edges being connected to one another by an arch 7, or heel loop.
The baseplate 4 extends along a longitudinal direction L₁of the binding, between a front end 8 and a rear end 9.
A first linkage 11, or strap, and a second linkage 12, or strap, are provided to removably retain the boot on the binding 1. Strap 11 can be regarded as a toe strap and strap 12 can be regarded as an ankle strap. For reasons of convenience, only the first strap 11 is described hereinafter.
In a non-limiting manner, the first strap 11 includes, for example, a cap 13 and a band 14, the assembly of the invention also including a ratchet device 15 for tightening the strap.
The cap 13, which includes one or more layers of flexible material, for example, extends from a fastening end 20 to a free end 21. The fastening end 20 is affixed to the medial edge 6, for example by an articulation that allows the fastening end 20 to rotate. The cap 13 can include a plurality of sections structured and arranged so as to adjust the length of the cap.
The band 14 extends in a longitudinal direction L₁₄, from a fastening end 25 to a free end 26. In this case, the fastening end 25 is affixed to the lateral edge 5, for example by an articulation that allows the fastening end 25 to rotate.
The band 14 here includes serrations 27 arranged on a core 28. The serrations 27 and the core 28 form a unitary element, made of a plastic, for example. The serrations 27 includes a lengthwise succession of teeth 29 arranged in a uniform pattern. Each tooth 29 has a meshing surface 30 and an engagement surface 31 that are provided to cooperate with the tightening device 15, as is explained below. The junction of the surfaces 30, 31 forms an upper edge of the tooth 29. The meshing surface 30 is oriented perpendicular to the band 14 in order to obtain a stable meshing with other components of the tightening device 15.
The structure and functioning of the ratchet tightening device 15 are explained hereinafter with reference to FIGS. 2 to 8.
FIG. 2 shows a side view of the tightening device 15. It includes a U-shaped base 33 provided to guide the band 14. The base 33 includes a first flange 34 and a second flange 35 connected by a bridge 36.
The base 33 is affixed to the cap 13, for example by means of a rivet having an axis 37, so that the device 15 is located in the area of the free end 21 of the cap.
As shown in FIG. 3, the tightening device 15 includes a pawl 40 articulated about an axis 41, manifested by a pin, e.g., extending along such axis, between the flanges 31, 32. An elastic mechanism, such as a spring, such as a torsion spring mounted about the pin or other such mechanism well-known to those skilled in the art, constantly biases the pawl 40, so that a retaining zone 42 of the pawl is pushed towards the bridge 36. The retaining zone 42 is shown in the form of a tooth.
A driving lever 43 includes a handling end 44, on the one hand, and a driving end 45 provided with at least one tooth 46, on the other hand. The driving lever 43 is articulated about an axis 47, manifested by a pin, e.g., extending along such axis, between the flanges 34, 35. An elastic mechanism, not shown, such as a spring, constantly biases the lever 43, so that the handling end 44 is pushed towards the bridge 36.
A release button 50 has a cam surface 51 provided to press on a cam surface 52 of the pawl 40, and an engageable end 53 provided to be actuated by one's hand or thumb, for example. The release button 50 is articulated about an axis 54, manifested by a pin, e.g., extending along such axis, between the flanges 34, 35. The driving lever 43 and the release button 50 are articulated along different respective axes 47, 54.
According to the first embodiment of the invention, the axes 41, 47, and 54 of the pawl 40, the lever 43, and the button 50, respectively, are parallel to one another. These axes 41, 47, 54 are oriented along a transverse direction W₁₅of the tightening device 15. See FIG. 6. This direction W₁₅is parallel to the bridge 36, and merges with the transverse direction W₁₄of the band 14, when the band is inserted in the tightening device 15. The transverse direction W₁₄of the band 14 is parallel to a surface of the strap, and perpendicular to the longitudinal direction L₁₄.
In the absence of any external bias, the constituent parts of the tightening device 15 each occupy the position shown in FIG. 3.
Because the band 14 is present along the bridge 36 between the flanges 34, 35, i.e., in the base 33, the pawl 40 opposes a lengthening of the strap 11. This means that the free end 26 of the band 14 cannot move in a direction that extends from an inner edge 56 towards an outer edge 57 of the base 33.
A displacement in the opposite direction, however, is possible. This displacement can be caused by the user, as shown in the case of FIG. 4.
The driving lever 43 is actuated using the end 44, so that the teeth 46 drive the band 14. In this case, the free end 26 of the band 14 moves in a direction that extends from the outer edge 57 towards the inner edge 56. This means that the strap 11 becomes shorter, and the boot tightening becomes stronger.
Conversely, to loosen the strap, or even to release the boot by opening the strap, the user only needs to proceed as shown in FIG. 5.
In this case, the driving lever 43 is not biased because its handling end 44 occupies the position nearest to the bridge 36. Using a finger, for example, the user actuates the handling end 53 of the release button 50.
The cam surface 51 of the button 50 presses on the cam surface 52 of the pawl 40, so that the retaining zone 42 of the pawl 40 moves away from the bridge 36 and from the band 14. The strap 11 can lengthen, because the pawl 40 no longer retains the band 14.
As soon as the action of the button 50 ceases, the pawl 40 reassumes a retaining position.
An advantage, brought about by the structure of the tightening device 15, is that the manual actuation of the release button 50 allows the strap 11 to lengthen and to open.
According to the invention, as can be understood in particular from FIGS. 1 and 6 to 8, for at least one tooth 29 of the serrations 27 of the band 14, at least one straight line d1, d2, tangent to the meshing surface 30 of the tooth 29 and parallel to a surface of the band 14, forms, together with the longitudinal direction L₁₄of the strap, an angle α1, α2 that is less than 90 degrees; the driving end 45 of the lever 43 is configured to cooperate with the serrations 27 of the band 14; and the retaining zone 42 of the pawl 40 is configured to cooperate with the serrations 27 of the band 14.
For at least one tooth 29, at least a portion of the meshing surface 30 is not perpendicular to the longitudinal direction L₁₄.
Compared to a prior art strap, the tightening device 15 and the band 14 of the invention provide an increased meshing surface between the driving lever 43 and the band, or between the pawl 40 and the band. The comparison is based on a similar space requirement, i.e., for tightening devices and bands of similar sizes. Consequently, the contact pressure exerted on each tooth is reduced, whether on the band, the driving lever, or the pawl.
One of the resulting advantages is the reduced or even insignificant wear on the teeth. Consequently, tooth disengagement, in particular during tightening of the strap, is rare or even non-existent. Moreover, the arrangement according to the invention increases the progressiveness of the tightening. Furthermore, as will be become better understood for the description that follows, friction between the band and the tightening device is reduced. This improves tightening efficiency.
According to the first embodiment of the invention, for a tooth 46 of the lever 43 in contact with the serrations 27 of the band 14, at least one straight line d3, d4, tangent to the meshing surface 60 of the tooth 46 of the lever and parallel to a surface of the band 14, forms, together with the longitudinal direction L₁₄of the band, an angle α3, α4 that is less than 90 degrees.
In the same context, for a tooth 42 of the pawl 40 in contact with the serrations 27 of the band 14, at least one straight line d5, d6, tangent to the meshing surface 70 of the tooth 42 of the pawl and parallel to a surface of the band 14, forms, together with the longitudinal direction L₁₄of the band, an angle α5, α6 that is less than 90 degrees.
The diagrams according to FIGS. 7 and 8 include references relating to the band 14, the pawl 40, and the lever 43. The teeth 29, 42, 46, of the band 14, the pawl 40, and the lever 43, respectively, are identical or similar in their shapes. In particular, the teeth 42, 46 of the pawl 40 and the lever 43 each have a shape that is similar to that of a tooth 29 of the band. This enables a reliable meshing of the pawl and/or the lever with the band.
According to the first embodiment of the invention, in a non-limiting manner, each tooth 29, 42, 46 of the band 14, the pawl 40, and the lever 43, is generally V-shaped. In other words, the general shape of a tooth is that of a herringbone. Because of this shape, the band 14 rubs slightly, or does not rub at all, on the flanges 34, 35 of the ratchet device 15 during tightening of the strap 11. In other words, the V-shape makes it possible to center the band 14 between the flanges 34, 35. As a result, tightening efficiency is advantageously better.
For reasons of convenience, it is a tooth 29 of the band 14 that is described more in detail hereinafter. However, it is to be understood that what is explained for the tooth 29 of the band 14 applies to a tooth 42 of the pawl 40 and a tooth 46 of the lever 43.
As it appears in particular in FIGS. 7 and 8, the meshing surface 30 of the tooth 29 includes a first facet 81 and a second facet 82. Each facet 81, 82 is a straight portion of the meshing surface 30. The junction of the facets 81, 82 forms the tip of the V. Given that the meshing surface 30 is perpendicular to the band 14, the facets 81, 82 are perpendicular to the band. This improves the transmission of the tightening forces coming from the lever 43, as well as the retention of the band 14 by the pawl 40. Consequently, the engagement surface 31 is inclined, in the sense that, along the longitudinal direction L₁₄, the engagement surface 31 forms, together with the core 28, an angle whose value ranges between 10 and 70 degrees. It is the engagement surface of each tooth 29 that moves the pawl 40 apart during tightening of the strap 11.
In a non-limiting manner, the serrations 27 are provided to be transversely symmetrical. For this reason, each tooth 29 is transversely symmetrical relative to a central longitudinal axis, designated by the reference numeral L₁₄, of the band 14. Consequently, the junction of the facets 81, 82 is halfway between a first transverse edge 83 and a second transverse edge 84 of the band 14. This improves tightening efficiency, as explained above, but also provides greater tightening uniformity. In fact, the band 14 travels in a more uniform manner in the tightening device 15 during the action of the driving lever 43.
Indeed, during an intermediate phase of the band 14 being driven by the lever 43, as seen in FIG. 7, lateral portions 91, 92 of a reference tooth 46 of the lever 43 are in mesh with a reference tooth 29 of the band 14, while a central portion 93 of an adjacent tooth 46 of the lever 43 is in mesh with an adjacent tooth 29 of the band 14. It is always the entire usable surface of a meshing surface 30, 60 that is used, this usable surface being distributed on two adjacent teeth 29, 46.
During another intermediate phase of the band 14 being driven, as seen in FIG. 8, a tooth 46 of the lever 43 in its entirety is in mesh with a tooth 29 of the band 14. Here again, it is the entire usable surface of a meshing surface 30, 60 that is used.
Therefore, in short, the tightening of strap 11 is carried out by the uniform, successive meshing of teeth of the band and of the lever.
Each tooth 29 of the band 14 extends over the entire width thereof, i.e., from the first transverse edge 83 to the second 84.
The angle of the V of the tooth 29 of the band 14 ranges between 60° and 170°. For example, angle values in a range from 120° to 140° are suitable. Consequently, the angles α1, α2 are comprised between 30° and 85°. Because the serrations 27 are transversely symmetrical, the angles α1, α2 have the same value.
As a consequence of the foregoing, the angle of the V of a tooth 42, 46 of the pawl 40 or of the lever 43 ranges between 60° and 170°. Therefore, each tooth 42, 46 of the pawl or of the lever extends over the entire width of the pawl or of the lever, respectively. Furthermore, each tooth 42, 46 of the pawl or of the lever is transversely symmetrical, i.e., relative to a central axis that is perpendicular to its articulation axis 41, 47, respectively.
The other embodiments of the invention are described hereinafter with reference to FIGS. 9 to 11. For reasons of convenience, the common elements shared with the first embodiment are designated by the same reference numerals.
Thus, the second embodiment, according to FIG. 9, features a strap 11 having a cap 13, a band 14 and a tightening device 15. The latter also includes a pawl 40, a lever 43, and a release button 50.
What is specific to the second embodiment is that the driving lever 43 and the release button 50 are articulated about a common axis 47, i.e., about the same axis. This arrangement simplifies the structure of the tightening device 15.
The third embodiment, according to FIG. 10, distinguishes over the other embodiments by the shape of the teeth 29 of the band 14. The shape of the teeth of the pawl and of the lever is similar to that of the band. In fact, each tooth 29, 42, 46 of the band 14, the pawl 40, and the lever 43 has the general shape of a curve, in particular in the area of the meshing surface 30. For example, the curve can be a circular arc, a parabolic arc, or the like. A curved shape provides continuity to each tooth, in particular at the meshing surface 30. Here again, each tooth is transversely symmetrical.
The fourth embodiment, according to FIG. 11, distinguishes over the other embodiments by the shape of the teeth 29 of the band 14. Again, the shape of the teeth of the pawl and the shape of the lever are similar to that of the band. Each tooth 29, 42, 46 of the band 14, the pawl 40, and the lever 43 has an alternation of facets 101, 102, 103, 104, particularly in the area of the meshing surface 30. In a non-limiting manner, these facets are arranged uniformly, in the transverse direction, so as to form two successive herringbones. This embodiment provides the same advantages as those of the first embodiment.
Generally, the constituent elements of the invention are manufactured with materials and according to techniques known to those of ordinary skill in the art.
The invention is not limited to the particular embodiments described and illustrated herein, and includes all of the technical equivalents that fall within the scope of the claims that follow.
For example, other shapes can be provided for the teeth, provided that, in most cases, the length of the meshing surface is greater than the width of the band, the pawl, or the driving lever.
A tooth can include a plurality of juxtaposed distinct sections.
A tooth can extend transversely over a range that is less than the width of the band, the pawl, or the driving lever.
A tooth can be transversely non-symmetrical.
Also, the ratchet tightening device can include a plurality of pawls.
As described and illustrated, the driving lever 43 drives the band 14 directly. Alternatively, however, the driving lever can drive the band 14 indirectly. For example, in this regard, the tightening device can include a toothed wheel arranged between the driving lever and the band. In this case, the pawl can be arranged to cooperate with the toothed wheel.
Furthermore, the use of a release button can be omitted. In such a case, the driving lever and the pawl are linked to the base by connecting rods. A forced rotation of such connecting rods moves the pawl apart from the band, which releases the band.
In general, an assembly according to the invention can include a binding, for example a strap-in snowboard binding. In such a case, at least one strap includes a ratchet tightening device and a band. An assembly can include any boot that includes a sole and an upper, the tightening device and the band being provided to tighten the upper. For example, the assembly can include a ski boot, a motorbike boot, a fireman's boot, a safety boot, a military boot, or the like.
The assembly can also include a bag.
Further, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.

Claims

1. An assembly comprising:

a band extending lengthwise in a longitudinal direction, from a fastening end to a free end;

the band comprising serrations, said serrations including a succession of teeth extending in said longitudinal direction;

a ratchet tightening device comprising:

a base;

a driving lever articulated to the base and including a driving end for driving the band along a first direction and a handling end;

a pawl articulated on the base and having a retaining zone provided to oppose displacement of the band along a second direction opposite the first direction; and

an elastic mechanism constantly biasing the retaining zone of the pawl towards the base;

for at least one tooth of said succession of teeth of the band, at least one straight line tangent to a meshing surface of the one tooth and parallel to a surface of the band forms, together with the longitudinal direction of the band, an angle less than 90 degrees;

the driving end of the lever being structured and arranged to cooperate with the succession of teeth of the band;

the retaining zone of the pawl being structured and arranged to cooperate with the succession of teeth of the band.

2. An assembly according to claim 1, wherein:

the lever includes a tooth;

for the tooth of the lever in contact with the one tooth of the succession of teeth of the band, at least one straight line, tangent to a meshing surface of the tooth of the lever and parallel to a surface of the band forms, with the longitudinal direction of the band, an angle less than 90 degrees.

3. An assembly according to claim 1, wherein:

the pawl includes a tooth;

for the tooth of the pawl in contact with the one tooth of the succession of teeth of the band, at least one straight line, tangent to a meshing surface of the tooth of the pawl and parallel to a surface of the band forms, with the longitudinal direction of the band, an angle less than 90 degrees.

4. An assembly according to claim 3, wherein:

each tooth of the band, the pawl, and the is generally V-shaped.

5. An assembly according to claim 4, wherein:

the angle of the V of each tooth of the band, the pawl, and the lever is between 60 and 170 degrees.

6. An assembly according to claim 3, wherein:

each tooth of the band, the pawl, and the lever, has a generally curved shape.

7. An assembly according to claim 3, wherein:

each tooth of the band, the pawl, and the lever, has an alternation of facets.

8. An assembly according to claim 3, wherein:

each tooth of the band, the pawl, and the lever, is transversely symmetrical.

9. An assembly according to claim 1, wherein:

the tightening device comprises a release button structured and arranged for applying a release force to the pawl;

the driving lever and the release button are articulated about respectively different axes.

10. An assembly according to claim 1, wherein:

the driving lever and the release button are articulated about a common axis.

11. An assembly according to claim 1, wherein:

the base has a first flange and a second flange connected by a bridge;

the lever is articulated on the base between the flanges;

the first driving direction is substantially parallel to the flanges and to the bridge;

the pawl is articulated on the base between the flanges;

the elastic mechanism biases the retaining zone of the pawl towards the bridge.

12. An assembly according to claim 1, wherein:

the tightening device includes a release button;

the release button is structured and arranged to bias the retaining zone of the pawl against a force exerted by the elastic mechanism.

13. An assembly according to claim 1, further comprising:

a boot, the boot including a sole and an upper, the tightening device and the strap being affixed to the boot and structured and arranged to tighten the upper against a foot or lower leg of a wearer.

14. An assembly according to claim 13, wherein:

the boot is a ski boot, constructed and arranged to be secured to a ski by means of a binding engaging the ski boot.

15. A snowboard binding assembly for binding a snowboard boot to a snowboard, said assembly comprising:

at least two straps, at least one of said straps including a ratchet tightening device and a band;

the band extending lengthwise in a longitudinal direction, from a fastening end to a free end;

the ratchet tightening device comprising:

a base;

16. An assembly according to claim 15, further comprising:

a baseplate;

a lateral edge extending upwardly from the baseplate;

a medial edge extending upwardly from the baseplate;

a heel loop extending between the lateral and medial edges;

the fastening end of the band being fastened to one of the lateral and medial edges.