Patent Description:
In daily life, cords, such as a lace or a thread, are usually used to tighten articles. The most common tightening method is to use the cord to reciprocately pass through holes on the article, e.g., eyelets of a shoe, and then tie a knot to secure the article. But in this kind of tightening method, the knot is loosened easily owing to an external force. Not only does the knot need to be tied again, but also lots of inconveniences come owing to the insecurity of the articles.

In order to solve such problems, some practitioners developed a simple fastening mechanism including a case, an engaging unit and a spring. The case includes holes configured for the lace to pass therethrough. Through the reaction force between the spring and the engaging unit, the lace can be clamped between the engaging unit and the case so as to be fastened. The length of the lace can be changed by pressing the spring to change the position of the engaging unit. However, in such fastening mechanism, the restoring force of the spring is served as the securing force; thus, the lace is easily to be released owing to vibrations or an external force. In addition, the fastening mechanism has no space for receiving the lace, and the exposure of the lace may bring danger.

Therefore, some practitioners developed another kind of buckle which can be rotated to tighten the lace, and the lace can be received inside the buckle. Through the interference between components inside the buckle, the length of the lace as well as the tightness can be adjusted. However, the structure of the buckle is complex; as a result, the manufacturing cost is increased, and the buckle has assembly and repair difficulty. A prior technique can be seen in <CIT>, the title thereof being "Fastening device and installation method for thread thereof", and the prior technique discloses a fastening device including a housing, a bobbin, a knob and a detent unit.

Hence, the inner structure of the buckle is continuously improved by the practitioners, with a hope that the structure can be simplified while the securing capability thereof is remained, and the structure reliability thereof is increased to prevent shortness of the lifetime.

Based on the above-mentioned problems, how to simplify the structure of the fastening device, reduce the manufacturing cost and maintain the securing capability becomes a pursuit target for practitioners.

The present disclosure provides a fastening device having the features of claim <NUM>. Preferred embodiments are subject matter of the dependent claims.

Accordingly, a fastening device is provided, which includes a case unit, a knob, an engaging unit and a spool. The case unit has an axial direction. The knob covers on the case unit along the axial direction. The engaging unit is coupled to the knob and includes an annular body and a pawl arm, the pawl arm has a proximal end and a distal end, and the proximal end is connected to the annular body. The spool is configured for a lace to wind therearound. The engaging unit further includes an engaging portion, and the engaging portion is located on the pawl arm and protrudes outward along a radial direction of the case unit. A first distance D<NUM> is contained between the proximal end and the distal end, a second distance D<NUM> is contained between the engaging portion and the proximal end, and a relationship of D<NUM> ≤ (2D<NUM> / <NUM>) is satisfied. One of the knob and the case unit includes a plurality of mounting teeth, and the pawl arm is selectively engaged with at least one of the mounting teeth. The engaging unit is driven by the knob to switch between a first position and a second position along the axial direction. When the engaging unit is in the first position, the engaging unit prohibits the spool from releasing the lace. When the engaging unit is in the second position, the engaging portion is engaged with at least one of the mounting teeth, and the engaging unit does not prohibit the spool from releasing the lace.

According to one embodiment of the aforementioned fastening device, the pawl arm can have a first height H<NUM>, the engaging portion can have a second height H<NUM>, and the relationship of H<NUM> ≤ (H<NUM> / <NUM>) is satisfied. The pawl arm can include a height central line, and the engaging portion is lower than or flush with the height central line.

According to one embodiment of the aforementioned fastening device, the first distance D<NUM> and the second distance D<NUM> can satisfy the relationship of D<NUM> = (D<NUM> / <NUM>).

The embodiment will be described with the drawings. For clarity, some practical details will be described below. However, it should be noted that the present disclosure should not be limited by the practical details. That is, in some embodiment, the practical details are unnecessary. In addition, for simplifying the drawings, some conventional structures and elements will be simply illustrated, and repeated elements may be represented by the same labels.

In addition, it will be understood that when an element (or mechanism or module) is referred to as being "disposed on", "connected to" or "coupled to" another element, it can be directly disposed on, connected or coupled to the other one element, or it can be indirectly disposed on, connected or coupled to the other one element, that is, intervening elements may be present. In contrast, when an element is referred to as being "directly disposed on," "directly connected to" or "directly coupled to" another element, there are no intervening elements present. The terms first, second, third, etc. are used herein to describe various elements or components, these elements or components should not be limited by these terms. Consequently, a first element or component discussed below could be termed a second element or component.

Please refer to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. <FIG> shows a three dimensional schematic view of a fastening device <NUM> according to one embodiment of the present disclosure. <FIG> shows one exploded view of the fastening device <NUM> of <FIG>. <FIG> shows another exploded view of the fastening device <NUM> of <FIG>. <FIG> shows one cross-sectional view of the fastening device <NUM> of <FIG>. <FIG> shows another cross-sectional view of the fastening device <NUM> of <FIG>. <FIG> shows one cross-sectional view of the fastening device <NUM> of <FIG> taken along line <NUM>-<NUM>. <FIG> shows one cross-sectional view of the fastening device <NUM> of <FIG> taken along line <NUM>-<NUM>. <FIG> shows one cross-sectional view of the fastening device <NUM> of <FIG> taken along line <NUM>-<NUM>. The fastening device <NUM> includes a case unit <NUM>, a knob <NUM>, an engaging unit <NUM> and a spool <NUM>.

The case unit <NUM> has an axial direction I1 and includes a plurality of mounting teeth <NUM>. The knob <NUM> covers on the case unit <NUM> along the axial direction <NUM>. The engaging unit <NUM> is coupled to the knob <NUM> and includes an engaging portion <NUM>. The spool <NUM> is configured for a lace (not shown) to wind therearound. The engaging unit <NUM> is driven by the knob <NUM> to switch between a first position and a second position along the axial direction I1. When the engaging unit <NUM> is in the first position, the engaging unit <NUM> prohibits the spool <NUM> from releasing the lace, that is, prohibiting the spool <NUM> from rotating to a first direction A1. When the engaging unit <NUM> is in the second position, the engaging portion <NUM> is engaged with at least one of the mounting teeth <NUM>, and the engaging unit <NUM> does not prohibit the spool <NUM> from releasing the lace, that is, not prohibiting the spool <NUM> from rotating to the first direction A1.

Hence, when the engaging unit <NUM> is in the second position, the engaging portion <NUM> is engaged with at least one of the mounting teeth <NUM>, and the structure relationship thereof is favorable for the engaging unit <NUM> to switch from the second position to the first position successfully, thereby increasing the structural reliability. The detailed structure of the fastening device <NUM> will be described hereafter.

The case unit <NUM> has a radial direction, and the case unit <NUM> can further include an annular wall <NUM> and a base <NUM>. The annular wall <NUM> surrounds an inner space <NUM>. The base <NUM> is configured for the annular wall <NUM> to be disposed thereon, and the annular wall <NUM> can be disposed on the base <NUM> via means of engagement. The mounting teeth <NUM> are located on the annular wall <NUM> and face toward the inner space <NUM>, and the mounting teeth <NUM> are located at an upper end of the annular wall <NUM>.

The spool <NUM> is hollow ring-shaped. The spool <NUM> is located in the inner space <NUM> and includes an annular track <NUM> and a plurality of engaging teeth <NUM>. The annular track <NUM> is configured for a lace to wind therearound, and the engaging teeth <NUM> are selectively coupled to the engaging unit <NUM>. When the spool <NUM> is driven to rotate, the lace can be retracted or released as the spool <NUM> rotates in different directions.

The knob <NUM> includes a guiding track <NUM>, a post <NUM>, and two positioning blocks <NUM>. The guiding track <NUM> is disposed on an inner wall of the knob <NUM>. The post <NUM> protrudes toward the inner space <NUM> along the axial direction I1, and the two positioning blocks <NUM> are symmetrically disposed on an outside of the post <NUM> along the radial direction.

The engaging unit <NUM> includes an annular body <NUM>, two retaining portions <NUM>, <NUM>, three guiding portions <NUM>, three pawl arms <NUM>, three engaging portions <NUM>, a plurality of driving teeth <NUM>, a central hole (not labeled) and two protrusions <NUM>, <NUM>. The central hole is located at a center of the annular body <NUM>, and the guiding portions <NUM> have bevel gear structures protruding outward from the annular body <NUM> and are used for coupling to the knob <NUM>. The two retaining portions <NUM>, <NUM> protrude inwardly from the annular body <NUM> and are disposed symmetrically to each other. Each of the retaining portions <NUM>, <NUM> includes a free end <NUM>, <NUM>. The free ends <NUM>, <NUM> can move in the radial direction after being forced by an external force, and can be restored after the external force is removed. The two protrusions <NUM>, <NUM> protrude inwardly from the annular body <NUM>, and an interval is contained between each of the two protrusions <NUM>, <NUM> and each of the two free ends <NUM>, <NUM>. The driving teeth <NUM> are located at a bottom side of the annular body <NUM> and can be selectively engaged with the engaging teeth <NUM> of the spool <NUM>.

Each of the pawl arms <NUM> is selectively engaged with at least one of the mounting teeth <NUM>, and each of the pawl arms <NUM> includes a distal end <NUM> and a proximal end <NUM>. The proximal end <NUM> is connected to an outside of the annular body <NUM>, and the distal end <NUM> is configured to detachably engage with the mounting teeth <NUM>. Each of the three engaging portions <NUM> is located on each of the pawl arms <NUM> and protrudes radially outward, and the engaging portions <NUM> are configured as single-tooth structures. Moreover, the pawl arm <NUM> has a first height H<NUM>, the engaging portion <NUM> has a second height H<NUM>, and a relationship of H<NUM> ≤ (H<NUM> / <NUM>) is satisfied. Furthermore, the pawl arm <NUM> has a height central line L1, and the engaging portion <NUM> is lower than or flush with the height central line L1. In the embodiment of <FIG>, the engaging portion <NUM> is lower than the height central line L1. It should be noted that the above-mentioned first height H<NUM> represents the maximum height of the pawl arm <NUM> along the axial direction I1. Therefore, if the height of each portion of the pawl arm <NUM> is different, the maximum height is taken as the first height H<NUM>.

As shown in <FIG> and <FIG>, the engaging unit <NUM> is in the first position, the driving teeth <NUM> of the engaging unit <NUM> are engaged with the engaging teeth <NUM> of the spool <NUM>, when the above-mentioned condition is satisfied, the distal end <NUM> of the pawl arm <NUM> (shown in <FIG>) is engaged with the mounting teeth <NUM> in the first direction A1 (shown in <FIG>), the distal end <NUM> of the pawl arm <NUM> is continuously disengaged with the mounting teeth <NUM> in a second direction A2 (shown in <FIG>), and the engaging portion <NUM> are not engaged with the mounting teeth <NUM> owing to that its position is relatively lower than the mounting teeth <NUM>. Therefore, rotating the knob <NUM> in the second direction A2 can drive the engaging unit <NUM> to actuate the spool <NUM> to retract the lace, and when the knob <NUM> is immobile, the distal end <NUM> of the pawl arm <NUM> abuts against the mounting teeth <NUM> to prevent the spool <NUM> from rotating toward the first direction A1, thereby preventing the lace from being released.

Furthermore, rotating the knob <NUM> in the first direction A1 allows the engaging unit <NUM> to be raised along the axial direction I1, such that the engaging unit <NUM> is disengaged from the spool <NUM>. Precisely, when the engaging unit <NUM> is in the first position, the guiding portion <NUM> is engaged with the guiding track <NUM> of the knob <NUM>, as shown in <FIG>, one of the positioning blocks <NUM> is located between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>, and the other one of the positioning blocks <NUM> is located between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>. When the knob <NUM> is rotated in a first direction A1, the engaging unit <NUM> is unable to be rotated simultaneously owing to the engaging relationship between the pawl arm <NUM> and the mounting teeth <NUM>. Therefore, the two positioning blocks <NUM> respectively press against the two free ends <NUM>, <NUM>, and the two free ends <NUM>, <NUM> are deformed in the radial direction so that the knob <NUM> is able to be rotated relative to the engaging unit <NUM>. The guiding portion <NUM> is guided by the guiding track <NUM> to be raised in the axial direction I1 relative to the guiding track <NUM>, and the engaging unit <NUM> is switched to the second position. Meanwhile, one of the aforementioned positioning blocks <NUM> is changed to be located between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>, and the aforementioned other one of the positioning blocks <NUM> is changed to be located between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>.

As shown in <FIG>, since the engaging unit <NUM> is located in the second position, the driving teeth <NUM> of the engaging unit <NUM> are disengaged with the engaging teeth <NUM> of the spool <NUM>. Meanwhile, the spool <NUM> is not affected by the engaging unit <NUM>, and can be rotated in the first direction A1 (shown in <FIG>), such that the lace can be released by pulling the lace itself.

As shown in <FIG>, after the engaging unit <NUM> is raised along the axial direction I1, the relative position between the engaging portion <NUM> and the mounting teeth <NUM> is changed, and the engaging portion <NUM> is engaged with the mounting teeth <NUM>. If a user would like to secure or retract the lace again, the knob <NUM> can be rotated in the second direction A2, the two positioning blocks <NUM> press against the two free ends <NUM>, <NUM>, respectively, and the two free ends <NUM>, <NUM> are deformed in the radial direction such that the knob <NUM> can be rotated relative to the engaging unit <NUM>, thereby allowing the aforementioned one of the positioning blocks <NUM> to return to the place between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>, and allowing the aforementioned other one of the positioning blocks <NUM> to return to the place between the free end <NUM> of the retaining portion <NUM> and the protrusion <NUM>.

Generally, when the same force is applied, the ability of the pawl arm <NUM> to deform in the radial direction after being stressed is less than the ability of the retaining portions <NUM>, <NUM> to deform in the radial direction after being stressed. Therefore, when the knob <NUM> is rotated in the second direction A2, the pawl arm <NUM> is not easily deformed and the friction force between the pawl arm <NUM> and the mounting teeth <NUM> will be greater than the pressure that the retaining portions <NUM>, <NUM> can withstand, thereby preventing the engaging unit <NUM> from rotating with the knob <NUM>. Therefore, the two free ends <NUM>, <NUM> of the two retaining portions <NUM>, <NUM> can be pressed and deformed in the radial direction, thereby achieving the purpose of switching positions of the engaging unit <NUM>.

However, since the pawl arm <NUM> of the engaging unit <NUM> has been bent for a long time, the shaped thereof is easy to be fixed. Therefore, when the engaging unit <NUM> is in the second position, and the user would like to rotate the knob <NUM> in the second direction A2 to switch the engaging unit <NUM> to return to the first position, without the assistance from the engaging portion <NUM>, the friction force between the pawl arm <NUM> and the mounting teeth <NUM> will be insufficient owing to the fixed shape. When the knob <NUM> is rotated in the second direction A2 and the pawl arm <NUM> is continuously disengaged from the mounting teeth <NUM>, the two free ends <NUM>, <NUM> cannot be deformed by pressing of the two positioning blocks <NUM>, which leads to a situation that the engaging unit <NUM> cannot be switched.

According to the invention, the engaging portion <NUM> is provided, because the engaging portion <NUM> will engage with the mounting teeth <NUM>, rotating the knob <NUM> in the second direction A2 cannot make the pawl arm <NUM> be disengaged from the mounting teeth <NUM>, and the two positioning blocks <NUM> are able to force on the two free ends <NUM>, <NUM> to cause deformation, thereby achieving the purpose of switching positions.

Moreover, a first distance D<NUM> is contained between the proximal end <NUM> and the distal end <NUM>, a second distance D<NUM> is contained between the engaging portion <NUM> and the proximal end <NUM>, and the relationship of D<NUM> ≤ (2D<NUM> / <NUM>) is satisfied. Furthermore, the first distance D<NUM> and the second distance D<NUM> satisfy the relationship of D<NUM> = (D<NUM> / <NUM>). When the pawl arm <NUM> is engaged with the mounting teeth <NUM>, the deformation of the proximal end <NUM> is less than the deformation of the distal end <NUM>. Therefore, under long-term operation, the influence caused by the fixed shape is also smaller. When the configuration of the engaging portions <NUM> conforms to the above-mentioned relationship, the stability of the structure will be increased. In other embodiments, the engaging portions can also be disposed on the annular body and located below the guiding portions, and the present disclosure is not limited thereto.

It should be particularly noted that, in the embodiment shown in <FIG>, although the distal end <NUM> of the pawl arm <NUM> is still engaged with the mounting teeth <NUM> when the engaging unit <NUM> is in the second position. In other embodiments, when the engaging unit is in the second position, the distal end of the pawl arm can be completely disengaged from the mounting teeth and only the engaging portion is engaged with the mounting teeth, and it is not limited to the above disclosure.

In other embodiments, the mounting teeth can also be located on the knob. In other words, one of the knob and the case unit can include a plurality of mounting teeth, and it is not limited to the disclosure of the drawings.

Please refer to <FIG>, <FIG>, <FIG>, <FIG> and <FIG>. <FIG> shows a three dimensional schematic view of a fastening device 100a according to another embodiment of the present disclosure. <FIG> shows one exploded view of the fastening device 100a of <FIG>. <FIG> shows another exploded view of the fastening device 100a of <FIG>. <FIG> shows one cross-sectional view of the fastening device 100a of <FIG>. <FIG> shows another cross-sectional view of the fastening device 100a of <FIG>. The fastening device 100a includes a case unit 200a, a knob 500a, an engaging unit 400a, and a spool 300a. The operation of the fastening device 100a is similar to that of the fastening device <NUM> in <FIG>, and will be described as follows.

The case unit 200a includes an annular wall 220a, a case 270a, a base 210a, a spool space 250a, an inner space 240a, a communicating space 260a and a plurality of mounting teeth 230a. The spool space 250a is located on the base 210a, the case 270a covers on the base 210a to close the spool space 250a, the inner space 240a is located in the case 270a, and the communicating space 260a is also located in the case 270a, located at a lower side of the inner space 240a, and communicates with the inner space 240a. The annular wall 220a is located in the inner space 240a, and the mounting teeth 230a are disposed on the annular wall 220a and face toward the inner space 240a.

The engaging unit 400a includes an annular body (not labeled), two driving blocks 490a, three guiding portions 430a, three retaining portions 410a, three pawl arms 450a, three engaging portions 460a and a plurality of driving teeth 470a. The three guiding portions 430a, the three retaining portions 410a and the three pawl arms 450a are protrudingly disposed on an outside of the annular body, the two driving blocks 490a are protrudingly disposed on an inside of the annular body, the three engaging portions 460a are respectively located on the three pawl arms 450a, and the engaging portions 460a include double-teeth structures, which facilitates increasing the stability of the structure.

The knob 500a includes a post (not shown), a guiding track 510a, two positioning blocks 540a and three pushing blocks 530a. The guiding track 510a and the three pushing blocks 530a are disposed on an inner wall of the knob 500a. The relationship between the post and the two positioning blocks 540a is similar to the structural relationship of the post <NUM> and the two positioning blocks <NUM> in <FIG>.

When the knob 500a is rotated toward the first direction A1, each of the pushing blocks 530a presses and deforms each of the retaining portions 410a, thereby allowing the knob 500a to rotate relative to the engaging unit 400a, the guiding portion 430a is guided by the guiding track 510a and raised relative to the guiding track 510a along the axial direction, and the engaging unit 400a is switched to the second position. On the contrary, when the knob 500a is rotated toward the second direction A2, each of the pushing blocks 530a presses and deforms each of the retaining portions 410a, thereby allowing the knob 500a to rotate relative to the engaging unit 400a, the guiding portion 430a is guided by the guiding track 510a and descended relative to the guiding track 510a along the axial direction, and the engaging unit 400a is switched to the first position.

The fastening device 100a further includes a first transmission gear 610a and a second transmission gear 620a. The first transmission gear 610a includes upper teeth 611a and lower teeth 612a, and the second transmission gear 620a includes external teeth 622a and internal teeth 621a.

The spool 300a is accommodated in the spool space 250a and includes engaging teeth 320a, the second transmission gear 620a is disposed above the spool 300a, and the internal teeth 621a are engaged with the engaging teeth 320a. The first transmission gear 610a is disposed in the communicating space 260a, the engaging unit 400a is disposed in the inner space 240a, the upper teeth 611a of the first transmission gear 610a are engaged with the driving teeth 470a of the engaging unit 400a, and the lower teeth 612a of the first transmission gear 610a are detachably engaged with the external teeth 622a of the second transmission gear 620a.

As shown in <FIG>, the engaging unit 400a is in the first position, the lower teeth 612a of the first transmission gear 610a are engaged with the second transmission gear 620a, and as the condition of the above-mentioned situations are satisfied, the distal end (not labeled) of the pawl arm 450a is engaged with the mounting teeth 230a in the first direction A1 while the distal end of the pawl arm 450a is continuously disengaged from the mounting teeth 230a in the second direction A2, and the engaging portion 460a is not engaged with the mounting teeth 230a owing to its position being relative lower than the mounting teeth 230a. Therefore, rotating the knob 500a in the second direction A2 can drive the engaging unit 400a to rotate the spool 300a in the first direction A1 to retract the lace, and when the knob 500a is immobile, the distal end of the pawl arm 450a abuts against the mounting teeth 230a, thereby preventing the spool 300a from rotating and preventing the lace from being released.

Claim 1:
A fastening device (<NUM>, 100a), comprising:
a case unit (<NUM>, 200a), having an axial direction (I1);
a knob (<NUM>, 500a), covered on the case unit (<NUM>, 200a) along the axial direction (I1);
an engaging unit (<NUM>, 400a), coupled to the knob (<NUM>, 500a) and comprising an annular body (<NUM>) and a pawl arm (<NUM>, 450a), wherein the pawl arm (<NUM>, 450a) has a proximal end (<NUM>) and a distal end (<NUM>), and the proximal end (<NUM>) is connected to the annular body (<NUM>); and
a spool (<NUM>, 300a), configured for a lace to wind therearound;
wherein:
the engaging unit (<NUM>, 400a) further comprising an engaging portion (<NUM>, 460a), the engaging portion (<NUM>, 460a) being located on the pawl arm (<NUM>, 450a) and protruding outward along a radial direction of the case unit (<NUM>, 200a), wherein a first distance D<NUM> is contained between the proximal end (<NUM>) and the distal end (<NUM>), a second distance D<NUM> is contained between the engaging portion (<NUM>, 460a) and the proximal end (<NUM>), and a relationship of D<NUM> ≤ (2D<NUM> / <NUM>) is satisfied;
wherein one of the knob (<NUM>, 500a) and the case unit (<NUM>, 200a) comprising a plurality of mounting teeth (<NUM>, 230a), the pawl arm (<NUM>, 450a) is selectively engaged with at least one of the mounting teeth (<NUM>, 230a), the engaging unit (<NUM>, 400a) is driven by the knob (<NUM>, 500a) to switch between a first position and a second position along the axial direction (<NUM>), when the engaging unit (<NUM>, 400a) is in the first position, the engaging unit (<NUM>, 400a) prohibits the spool (<NUM>, 300a) from releasing the lace, and when the engaging unit (<NUM>, 400a) is in the second position, the engaging portion (<NUM>, 460a) is engaged with at least one of the mounting teeth (<NUM>, 230a), and the engaging unit (<NUM>, 400a) does not prohibit the spool (<NUM>, 300a) from releasing the lace.