JP2002145008A - Cam buckle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cam buckle capable of preventing a webbing from being subjected to excessive clamping force and of retaining stable clamping force for a long time. SOLUTION: Projecting strip shaped tooth parts 12A1-12A8, 12B are formed on one cam surface 11 of a cam member 10. The apex angle of the rearmost projecting strip shaped tooth part in a designated fastening rotation direction P is smaller than those of forward projecting strip shaped tooth parts 12A1-12A8. The projecting strip shaped tooth parts 12A1-12A8 deform to eliminate the clamping force when the webbing is subjected to excessive tensile force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam buckle used for fixing an object such as a child seat to a fixed object.

[0002]

2. Description of the Related Art Conventionally, as this kind of cam buckle, one applied to a child seed is disclosed in Japanese Patent Application Laid-Open No. Hei 8-268222.

In this type of cam buckle, a cam having a wave portion on one side is rotatably mounted between a pair of side walls formed on both sides of a bottom cover having a predetermined holding member. The webbing is sandwiched between the member and the wave portion. The wavy portion is constituted by a plurality of wavy portions extending along the cam axis direction, and the distance between the apex of each wavy portion and the cam shaft is in a direction opposite to a predetermined tightening rotation direction of the cam. It is set so that it gradually increases toward it.

When the webbing is pulled in a predetermined direction with the webbing lightly inserted between the corrugated portion of the cam and a predetermined holding member on the bottom cover side of the case, the cam is driven in the tightening rotation direction. By rotating, the separation distance between the wave portion and the holding member on the case side gradually decreases, and the webbing holding force between the wave portion and the holding member increases.

[0005]

However, in the above-mentioned cam buckle, the greater the force for pulling the webbing in a predetermined direction, the smaller the separation distance between the wave portion and the holding member on the case side. In this case, since the pinching force of the webbing between the corrugated portion and the pinching member is almost endlessly increased, the webbing may be broken.

In order to prevent this, a cam stopper is provided on the case side so that the cam does not rotate more than a certain amount, so that even if the webbing is pulled by an excessive force, the separation distance between the wave portion and the holding member is predetermined. It is also possible to limit the upper limit of the holding force acting on the webbing between the wave portion and the holding member so as not to become smaller as described above. In this case, when the webbing is pulled by a certain force or more, the webbing slides out from between the corrugated portion and the predetermined holding member on the bottom cover side of the case.

However, in this case, if the thickness of the webbing is reduced due to, for example, long-term use of the webbing or repeated load, the pinching force of the webbing becomes significantly smaller than an initial value assumed in advance. is there.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cam buckle which can prevent the webbing from being broken by applying an excessive clamping force to the webbing and can maintain a stable clamping force for a long period of time.

[0009]

Means for Solving the Problems In order to solve the above problems,
A cam buckle according to claim 1, wherein a pair of cam support portions are erected on both sides of the substrate portion so as to face each other, and supported rotatably around a predetermined cam axis between the cam support portions, An outer peripheral portion facing the substrate portion has a cam surface capable of holding a webbing inserted between the substrate portion and the substrate portion,
A cam member which is biased to rotate in a predetermined rotation direction for holding the webbing, and a lever member for rotating the cam member in a direction opposite to the rotation direction, comprising: Protrusions parallel to the camshaft are formed in parallel around the camshaft, and the distance between the protuberances and the camshaft is such that the camshaft and the camshaft extend from the front to the rear in the rotational direction. It is set so as to gradually increase until the distance between the substrate portions is exceeded, and among the respective protruding tooth portions, the protruding tooth portion in the last row in the rotation direction is each protruding tooth portion on the front row side. The deformation strength is set higher than that.

According to a second aspect of the present invention, the deformation strength of the front row of ridge teeth is set so that the webbing is deformed when a predetermined high load larger than a normal load is applied to the webbing. It is preferable that the deformation strength of the last row of ridges is set so as not to deform even when the predetermined high load is applied to the webbing.

More specifically, each of the protruding ridges is formed in a substantially triangular cross section, and among the protruding ridges, the last row of the protruding ridges in the rotation direction. The configuration in which the apex angle of the tooth portion is larger than the apex angle of each protruding ridge portion on the front row side can be adopted.

According to a fourth aspect of the present invention, the projecting dimension of the last row of the protruding teeth of the respective protruding teeth is greater than the projecting dimension of each of the protruding teeth on the front row side. Greater is better.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cam buckle according to an embodiment of the present invention will be described below.

The cam buckle 1 includes a frame member 2 and a cam member 10 rotatably supported by the frame member 2, as shown in FIGS.

The frame member 2 is formed as a substantially U-shaped member as viewed from the front, in which a pair of cam supporting portions 5 are erected on both sides of the substrate portion 4 so as to face each other. The frame member 2 is formed, for example, by punching and bending a thick metal member into a predetermined shape.

The substrate portion 4 is formed in a plate-like member having a rectangular shape in a plan view, and is formed so that the webbing W can be sandwiched between the upper surface thereof and the cam member 10.

In the present embodiment, the mounting is performed from the rear edge of the substrate section 4 (for convenience, the left side of the cam buckle shown in FIG. The attachment piece 3 having the hole 3h is formed, and the attachment piece 3 can be attached to a predetermined member (for example, a portion to be attached to the infant child seed 51 as described later) via the attachment piece 3.

Each cam supporting portion 5 is a member for rotatably supporting the cam member 10 around a predetermined cam axis C.
In the present embodiment, a cam support hole 5h through which a cam shaft 9 described later can be inserted is formed substantially at the center of the plate-shaped member.

In the present embodiment, each cam support 5
The rear upper corner portion 5a is formed in an arc shape having a predetermined radius of curvature so that a lever member 25 described later rotates smoothly without interfering with the cam support portion 5. A notch 5b is formed in the front upper corner of each cam support 5, and each of the engagement ends 2 of the coil spring member 20 described later.
1a are respectively formed so as to be engageable.

The cam member 10 has a cam surface 11 which can be arranged on the outer peripheral portion of the columnar block so as to face the upper surface of the substrate portion 4.
Is formed. In the present embodiment, as an example, a configuration is adopted in which a part of the outer peripheral portion of the substantially cylindrical block body is extended outward and the cam surface 11 is formed on the extended outer peripheral portion.

The cam member 10 is formed with a cam shaft insertion hole 10h through which the cam shaft portion 9 can be inserted at a substantially central portion of the side view shape along the width direction.

Here, the camshaft portion 9 has an elongated rod-like portion 9a.
Has a disk-shaped head 9b formed at one end.
Then, with the cam member 10 disposed between the cam support portions 5 such that the cam shaft insertion holes 10h are aligned with the positions of the cam support holes 5h, the cam shaft portion 9 is moved from the distal end to the one side cam. The cam member 10 is rotatably supported around the predetermined cam axis C between the cam support portions 5 by being inserted into the support hole 5h, the cam shaft insertion hole 10h, and the other cam support hole 5h.

The cam member 10 is urged by a predetermined cam urging means in a predetermined tightening rotation direction P around the cam shaft C (see FIG. 2).

In this embodiment, the coil spring member 20 is used as the cam urging means (see FIGS. 2 and 3).
The coil spring member 20 is formed by bending a wire having elasticity such as a steel wire into a substantially U-shape, and allowing substantially central portions in the longitudinal direction of both side portions 21 to pass through the rod portions 9a of the cam shaft portion 9 respectively. In addition to being bent into the shape portion 20a, the end portions of both side portions 21 are bent in a substantially U-shape so as to be folded, and formed at the engagement end portion 21a. Then, the coil spring member 20 is attached to the cam member 10 in a holding manner, and the rod-shaped portion 9a of the cam shaft portion 9 is fixed to each ring-shaped portion between each outer surface of the cam member 10 and the inner surface of each cam support portion 5. 20a
Further, each engaging end 21a is engaged with the notch 5b of the cam support portion 5, and the horizontal punch 22 of the coil spring member 20 is pressed against the outer peripheral surface of the cam member 10 from behind. It is arranged to be accessible. This coil spring member 2
The cam member 10 is configured to be urged in the tightening rotation direction P by the elastic force of zero.

As shown in FIGS. 2 to 4, the cam surface 11 has ridges 12A1 to 12A parallel to the cam shaft C.
8 and 12B are formed in parallel around the camshaft C, and the camshaft C and each of the ridges 12A1 to 12A8, 1
2B (more precisely, each protruding tooth portion 12A1 to 12A8, 1
2B from the front in the tightening rotation direction P to the rear until the distance exceeds the distance D between the camshaft C and the substrate portion 5 (see FIG. 2). It is set to be large. In the present embodiment,
The camshaft C and the protruding ridge 12B in the last row in the tightening rotation direction P
Only the interval between them is set so as to exceed the interval D. In FIG. 4, circles C1 passing through the protruding vertices of the ridge 12A1 in the front row in the tightening rotation direction P around the cam shaft C are indicated by two-dot chain lines, and the ridges 12A1 to 12A1
An arc-shaped curve C2 at a predetermined cross section of the imaginary curved surface on which 2A8 and 12B are formed is indicated by a broken line, and an arc-shaped curve C3 concentric with the arc-shaped curve C2 and passing through the protruding vertex of the ridge 12B is indicated by a broken line.

When the cam surface 11 is located at a position behind the substrate portion 4 in the tightening rotation direction P,
And the camshaft C on the straight line connecting the shortest distance,
When one of the 2A1 to 12A8 and 12B is located forward of the tightening rotation direction P, a relatively large distance such that the webbing W can be inserted between the cam surface 11 of the cam member 10 and the substrate portion 4 is set. It will be in a state where it has been broken. Further, from this state, when the cam member 10 is rotated in the tightening rotation direction P by the urging force of the coil spring member 20 or the like, the rotation of the cam member 10 on the straight line connecting the substrate portion 4 and the camshaft C at the shortest distance with the rotation is performed. Of the protruding tooth portions 12A1 to 12A8, 12B, the one located from the rear in the tightening rotation direction P is located, and the cam member 1
The distance between the 0 cam surface 11 and the substrate portion 4 gradually decreases, and the webbing W can be sandwiched therebetween.

When the webbing W is pulled in the tightening direction Q (see FIG. 2) while the webbing W is sandwiched in this manner, the friction between the webbing W and the cam surface 11 causes the cam member 10 to be tightened. Following the rotation in the rotation direction P, the distance between the cam surface 11 of the cam member 10 and the substrate portion 4 is further reduced, and the clamping force of the webbing W is increased.

Further, each protruding ridge portion 12A1 to 12A8,1
2B, the ridged tooth portion 12 in the last row in the tightening rotation direction P.
B has a deformation strength of each ridge 12A on the front row side.
It is set higher than the deformation strength of 1 to 12A8. Specifically, when using this cam buckle, the webbing W
When a normal range of tensile force (depending on the intended use) is applied to each of the ridges 12A1 to 12A8, 1
2B is not deformed, and when a tensile force exceeding the normal range acts on the webbing W, the protruding ridge portion 12B is not deformed,
Each protruding ridge portion 12A1 to 12A8 is formed to such an extent that it is deformed (the effect of this will be described later).

In the present embodiment, in order to realize such a configuration, each of the protruding tooth portions 12A1 to 12A8, 12B is formed such that the front side in the tightening rotation direction P has a long side and the tightening rotation direction P
Is formed in a substantially triangular cross section in which the rear side is a short side, and the apex angle α of the ridge 12B is set to
(Only the vertex angle β of the protruding ridge 12A8 is shown in FIG. 4)
It is set to be a value larger than. Note that the apex angle β of each protruding ridge portion 12A1 to 12A8 may be the same. In this case, the thickness near the tip of the protruding tooth portion 12B is larger than the thickness near the tip of each protruding tooth portion 12A1 to 12A8. When pressed with strong force to the
Are the protruding ridges 12A1 to 12A8 on the front row side.
More difficult to deform. In the present embodiment, the center angle θ between the vertices of the ridges 12A1 to 12A8, 12B with respect to the camshaft C is set to be the same, and each vertex is slightly chamfered.

The entire cam member 10 or the portion of the cam surface 11 is made of aluminum or aluminum so that each of the ridges 12A1 to 12A8 can be easily deformed when strongly pressed against the webbing W. It is preferable to use a relatively soft material such as an alloy.

The configuration in which the deformation strength of the protruding tooth portion 12B is set higher than that of each of the protruding tooth portions 12A1 to 12A8 on the front row side is not limited to the above-described configuration.
It is possible to adopt a configuration in which 2B is formed of a material having a higher deformation strength than the material forming the protruding ridge portions 12A1 to 12A8.

The cam buckle is provided with a lever member 25 for rotating the cam member 10 in a direction opposite to the tightening rotation direction P as shown in FIGS.

The lever member 25 is made of resin or the like, and includes a cover 26 covering the cam member 10 supported by the pair of cam supports 5 of the frame member 2 together with the cam support 5, and a cover And an operation unit 29 connected to the rear of the control unit 26.

On both side walls 27 of the cover 26, insertion holes 27h through which the rods 9a of the cam shaft 9 can be inserted are formed. The rod-shaped portion 9a of the cam shaft portion 9 is set in a state where the insertion hole portion 27h is disposed at a position corresponding to the cam support hole 5h, and the respective side wall portions 27 are disposed outside the cam support portion 5. The cam member 10 is inserted through the cam shaft insertion hole 10h of the cam member 10 from the insertion hole portion 27h and the cam support hole 5h on one side to the cam support hole 5h and the insertion hole portion 27h on the other side. It is rotatably mounted around the cam shaft C. At this time, the locking piece 13 protruding outward from a part of the cam member 10 in the circumferential direction is engaged with the engaging concave portion 28 formed on the inner peripheral portion of the cover portion 26, 10
And the lever member 25 is configured to rotate together. Thus, when the operating portion 29 is rotated upward while the cam member 10 is rotated in the tightening rotation direction P, the cam member 10 moves in the opposite direction to the tightening rotation direction P. The webbing W is rotated so as to open the webbing W held between the cam surface 11 of the cam member 10 and the substrate portion 4.

The operation of the cam buckle configured as described above will be described.

First, in the normal use state, the lever member 2
The cam member 10 is rotated in the direction opposite to the tightening rotation direction P against the urging force of the coil spring member 20 by lifting the operation unit 29 of No. 5 upward. Then, the spacing between the substrate portion 4 and the cam member 10 becomes large, and the webbing W can be inserted between them, so that a desired amount of the webbing W is inserted between them. Next, when the operation unit 29 is released, the cam member 1 is biased by the coil spring member 20.
0 rotates in the tightening rotation direction P. This allows
The distance between the cam surface 11 of the cam member 10 and the substrate portion 4 is reduced, and the protrusions 12A1 to 12A8 and 12B are relatively close to the front row in the tightening rotation direction P and the substrate portion 4.
The webbing W is lightly sandwiched between them. From this state,
When the webbing W is pulled in the tightening direction Q with a force within a predetermined allowable range, as shown in FIG.
Is driven to rotate, and the cam surface 11 of the cam member 10 and the substrate portion 4 are rotated.
The dimension of the space between them becomes smaller, and the pinching force of the webbing W becomes larger. Normally, the webbing W is opened in this state. When the cam member 10 is rotated in the opposite direction of the tightening rotation direction P by lifting the operation unit 29 upward from this usage state, the webbing W can be opened. Becomes In this normal state, the protruding ridges 12A1 to 12A8 and 12B are not deformed, and the cam member 10 rotates accordingly even when the webbing W becomes thin due to a repeated load or the like. W can be pinched with a predetermined pinching force.

On the other hand, if the webbing W is pulled with a large force exceeding the normal range in the above-described use condition, the cam member 10
Is further driven to rotate, and as shown in FIG.
The rotation of the cam member 10 is stopped in a state where the cam member 10 is pressed against the cam member 10. When the webbing W is pulled with an excessive force from this state, as shown in FIG.
The distal ends of the 2A1 to 12A8 are deformed so as to be pressed against the webbing W by an excessive force and collapsed, so that the webbing W is sandwiched mainly by the sandwiching force between the protruding ridge 12B and the substrate 4, and the webbing W The gripping force of
The webbing W gradually starts to slide. In other words, the state where the webbing W is sandwiched by the plurality of ridges 12A1 to 12A8 and 12B due to the deformation of the distal end of each ridge 12A1 to 12A8 is changed to the single ridge 12B.
As a result, the state shifts to a state in which the webbing W is held, and the holding force of the webbing W is reduced, so that an excessive holding force is not applied to the webbing W. At this time,
The webbing W slides out without being pulled out of the cam buckle 1 at a stretch, while being held by the single ridged tooth portion 12B with a predetermined force.

When an excessive tensile force is applied to the webbing W in this manner, the protruding ridges 1 other than the protruding ridges 12B are formed.
In order to eliminate the pinching force of the webbing W by the 2A1 to 12A8 as much as possible, each of the ridges 12A1 to 12A8, 12
B, the protruding dimension of the last row of protruding ridges 12B in the tightening rotation direction P (the protruding dimension with respect to the virtual curved surface on which the protruding ridges 12A1 to 12A8, 12B are formed) is set to the value of It is preferable to make the protrusions 12A1 to 12A8 larger than the protrusion dimension (same as above) (in FIG. 4, the apex of the protrusion 12B is on the arc-shaped curve C3,
The vertices of the ridges 12A1 to 12A8 are slightly inside the arc-shaped curve C3). In this case, the cam shaft portion 9 and the cam shaft insertion hole 1
0h and a slight deformation of the cam peripheral portion between the cam support hole 5h and the cam support hole 5h, and the entire cam member 10 can be lifted slightly upward.
The webbing W is moved upward in the direction away from A8, and the pinching force of the webbing W by the protruding ridges 12A1 to 12A8 can be eliminated as much as possible.

FIGS. 7 to 9 show examples of the use of the cam buckle configured as described above.

FIG. 7 is a perspective view of an infant child seat 51 omitting cushions and the like. One end of a crotch webbing 53 is fixed to the front center of a seat 52 of the child seat 51. A buckle body 54 is attached to the end. Further, tongue members 57 and 58 are attached to the ends of shoulder webbings 55 and 56 which are respectively attached to the left and right shoulders of the child sitting on the seat 52 of the child seat 51. By inserting the tongue members 57 and 58 into the buckle main body 54, the tongue members 57 and 58 are configured to be detachably engaged with each other.

The shoulder webbings 55 and 56 are pulled out to the back side at the backrest 59 of the child seat 51 and are connected to each other. Then, one end of the length adjusting webbing 50 is connected to the connected portion, and the other end of the length adjusting webbing 50 passes from the drawer 51 a at the front of the child seat 51 through the lower side of the seat 52. Be withdrawn.

The cam buckle 1 is fixed to the drawer 51a, and the length adjusting webbing 50 is pulled out via the cam buckle 1. Then, after adjusting the withdrawal amount of the length adjusting webbing 50, the cam buckle 1 is adjusted.
By releasably holding and fixing the length adjusting webbing 50 at a predetermined position, the length of the two shoulder webbings 55 and 56 drawn out to the front side of the backrest 59 can be adjusted as desired.

The cam buckle 1 is not limited to the above-described child seeds 51. For example, when the luggage is fastened and fixed on a truck bed, the web buckle 1 is a belt-like member.
It can be used for various purposes of releasably holding and fixing.

According to the cam buckle 1 configured as described above, the deformation strength of the last row of the protruding teeth 12B in the tightening rotation direction P of the protruding teeth 12A1 to 12A8 and 12B is higher than that of the front row. Is set to be higher than the deformation strength of each of the ridged teeth portions 12A1 to 12A8.
When an excessive tensile force is applied to the ridges 12A1
To 12A8 to deform the protruding ridges 1
The pinching force of the webbing W by 2A1 to 12A8 is reduced, so that an excessive pinching force is applied to the webbing W and the webbing W can be prevented from breaking.

At the same time, the cam shaft C and each of the ridges 12A1
The distance between the protrusions 12A8 and 12B is set to gradually increase from the front to the rear in the tightening rotation direction P until the distance exceeds the distance between the camshaft C and the base plate 4. Since the strength is set to be higher than the deformation strength of each of the ridges 12A1 to 12A8 on the front row side, even the webbing W thinned by long-term use can be pinched with a predetermined pinching force, and the webbing W Breakage can be prevented.

Further, the cam member 10 is tightened in the tightening rotation direction P.
Since the lever member 25 is provided for pivoting the webbing W in the opposite direction, the webbing W can be easily released from being pinched.

Further, the cam member 10 is tightened in the tightening rotation direction P.
Since the cam urging member such as the coil spring member 20 urging the webbing W is provided, the webbing W can be more reliably held.

In particular, as a configuration for setting the deformation strength of the protruding tooth portions 12B higher than the deformation strength of the protruding tooth portions 12A1 to 12A8 on the front row side, each protruding tooth portion 12B is provided.
A1 to 12A8, 12B are each formed in a substantially triangular cross section, and the apex angle α of the last row of ridges 12B in the tightening rotation direction P is set to each ridge 12A1 to 1 on the front row side.
In the case of finishing larger than the vertex angle β of 2A8, for example, the entire cam member 10 or the cam surface 11 of the cam member 10
Can be easily and rapidly mass-formed by extrusion of aluminum or aluminum alloy.

Further, each protruding ridge portion 12A1 to 12A8,1
2B, the last row of ridges 12B in the tightening rotation direction P
The protrusion dimension of each protruding ridge 12A1
When the webbing W is pulled by an excessive force, the protrusions 12A1 to 12A8 are larger than the protrusion dimensions of the protrusions 12A1 to 12A8.
Since the pinching force of the webbing W by 12A8 can be eliminated as much as possible, the webbing W can easily slide out.

In this embodiment, the last row of ridges 12B is composed of a single sheet. However, it may be composed of a plurality of ridges 12B. In this case, the load is dispersed and the deformation strength is set higher. In addition, the same effect can be maintained in the following protruding tooth portion even if the first protruding tooth portion of the plurality is deformed.

[0051]

As described above, according to the cam buckle according to the first to fourth aspects of the present invention, the last row of teeth in the rotational direction of each of the teeth is the front row side. Since the deformation strength is set higher than each of the ridges, even if an excessive tensile force is applied to the webbing, the ridges on the front row can be deformed to deform the webbing. Of the webbing can be prevented from being applied to the webbing, and the webbing can be prevented from breaking.

Further, the distance between the protruding teeth and the camshaft is set so as to gradually increase from the front to the rear in the rotation direction until the distance exceeds the distance between the camshaft and the substrate. And the deformation strength of the protruding tooth portion of the last row in the rotational direction of the protruding tooth portions is set higher than that of each protruding tooth portion on the front row side, so that the protruding tooth portion is stable for a long period of time. Can maintain the clamping force.

Further, since the cam member is provided with a lever member for rotating the cam member in a direction opposite to the predetermined rotation direction, the webbing can be easily released from being pinched.

According to a third aspect of the present invention, each protruding tooth portion is formed in a substantially triangular cross section, and the top of the last protruding tooth portion in a predetermined rotation direction among the front protruding tooth portions. In the case where the corner is formed to be larger than the apex angle of each protruding ridge portion on the front row side, the entire cam member or the entire cam surface portion of the cam member is formed by extrusion molding of a predetermined material. This has the advantage that molding can be performed easily and quickly in large quantities.

Further, the projecting dimension of the last row of teeth in the predetermined rotation direction among the projecting teeth is the same as the projecting dimension of each projecting tooth on the front row side. When the webbing is pulled with an excessive force, the pinching force of the webbing W by each of the ridges other than the ridges in the last row may be eliminated as much as possible. Yes, the webbing slips out more easily.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cam buckle according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a cam buckle according to the first embodiment.

FIG. 3 is an exploded perspective view of the above cam buckle.

FIG. 4 is an enlarged side view of a main part showing a cam member.

FIG. 5 is an enlarged sectional view of a main part showing a state in which the webbing is sandwiched.

FIG. 6 is an enlarged sectional view of a main part showing another state in which the webbing is sandwiched.

FIG. 7 is a perspective view showing an infant child seat which is an example of one use object of the cam buckle.

FIG. 8 is a rear view showing the infant child seat of the above.

FIG. 9 is a sectional view showing the infant child seat of the above.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 cam buckle 2 frame member 4 substrate portion 5 cam support portion 9 cam shaft portion 10 cam member 11 cam surface 12A1 to 12A8 ridge tooth portion 12B ridge tooth portion 20 coil spring member 25 lever member C camshaft W webbing α apex angle β Apex angle

Claims (4)

[Claims] A frame member having a pair of cam supporting portions provided on both sides of a substrate portion opposed to each other; a frame member rotatably supported around a predetermined cam axis between the cam supporting portions; The outer peripheral portion opposing has a cam surface that can pinch the webbing inserted between the substrate portion and the cam member that is biased to rotate in a predetermined rotation direction to pinch the webbing, A lever member for performing a rotation operation in a direction opposite to the rotation direction, and a ridge tooth portion parallel to the cam shaft is formed on the cam surface in parallel around the cam shaft, and The spacing between the toothed portion and the camshaft is set so as to gradually increase from the front to the rear in the rotation direction until the spacing exceeds the spacing between the camshaft and the substrate, and Of the teeth, the last row of ridges in the rotation direction However, the cam buckle has a higher deformation strength than each of the ridges on the front row. 2. The cam buckle according to claim 1, wherein a deformation strength of the ridge portion on the front row side is deformed when a predetermined high load larger than a normal load is applied to the webbing. A cam buckle that is set so that the deformation strength of the ridge tooth portion in the last row is not deformed even when the predetermined high load is applied to the webbing. 3. The cam buckle according to claim 1, wherein each of the ridges is formed in a substantially triangular cross section, and the ridge in the rotation direction is the last of the ridges. A cam buckle in which the apex angle of each row of protruding teeth is greater than the apex angle of each protruding tooth on the front row side. 4. The cam buckle according to claim 1, wherein a protrusion dimension of the last row of the protruding ridges among the respective protruding ridges is larger than that. A cam buckle that is larger than the projected dimension of each ridge on the front row.