JP2000296823A - Label expansion mechanism and label application device having label expansion mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a label expansion mechanism and a label application device having the label expansion mechanism capable of being adapted for a plurality of different sized stretch labels (of different diameters). SOLUTION: There are provided an annular disc 26 formed with can grooves 27 extending from on a concentric circle C1 of small diameter corresponding to a closing position with its center of rotation being applied as a center onto a concentric circle C2 of large diameter corresponding to an opening position while being extended in a rotating direction; a sliding member 28 sliding in a direction of diameter of the annular disc 26; and cam followers 30 having opening or closing claws 29 for expanding the labels attached to each of the sliding members 28 and fitted to the can grooves 27. The annular disc 26 is rotated in a reverse direction to cause the cam followers 30 to be moved along the cam grooves 27, resulting in that the opening or closing claws 29 are opened or closed between the opened position and the closed position. At an intermediate position of the cam grooves 27 is set in advance a stopping region 27a for each of the opening or closing claws 29 extending along a concentric circle C3 with the rotary center of the annular disc 26 being applied as a center.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label expanding mechanism for expanding a stretch label larger than the outer diameter of the object when the stretch label is mounted on the object to be mounted such as a bottle or a bottle. The present invention relates to a label mounting device provided with a label expanding mechanism.

[0002]

2. Description of the Related Art A label mounting apparatus for mounting a tubular stretch label on an outer peripheral surface of an object to be mounted such as a bottle or a bottle is usually provided with a label expanding mechanism having an opening / closing claw.
After inserting the tubular stretch label into the closed opening / closing claw and opening the opening / closing claw, the stretch label is expanded larger than the outer diameter of the object to be mounted, and the expanded stretch label is The stretch label is attached to the object by inserting the object.

[0003] As a label expanding mechanism, for example, FIG.
There is something like that shown in This label expanding mechanism 50
An annular disk 51 having a cam groove 52;
Sliding member 53 that slides in the radial direction of the annular disk 51 above
And two pairs of opening / closing pawls 54 of the same shape fixed to the sliding member 53 for expanding the stretch label L. The sliding member 53 is formed on the annular disk 51. A cam follower 55 that fits into the cam groove 52 is attached.

[0004] As shown in the figure, the cam groove 52 extends in the rotational direction from a small diameter concentric circle D1 corresponding to the closing position and centered on the rotation center of the annular disk 51, and corresponds to the opening position. It has a shape extending up to a large diameter concentric circle D2, and is driven by a driving mechanism (not shown) to form an annular disk 51.
Is rotated in the direction indicated by the arrow in the same figure, as shown in FIG. 14, the sliding member 53 is moved radially inward of the annular disk 51 by the cam mechanism including the cam groove 52 and the cam follower 55. Thus, the two pairs of opening / closing claws 54 are respectively closed.

As shown in FIG. 14, when a tubular stretch label L is inserted into the open / close claw 54 and the annular disk 51 is rotated in the opposite direction, the two pairs of open / close claw 54 are opened. Then, the stretch label L inserted into the opening / closing claw 54 is expanded.

[0006]

By the way, the label expanding mechanism 50 as described above can only support a stretch label L of a specific size (diameter).
If the stretch label to be expanded is changed to a stretch label with a different size (diameter), it must be replaced with another circular disk with a cam groove corresponding to the changed stretch label. There is a problem that it takes time and effort to change the setup, and it is necessary to prepare an annular disk for each stretch label having a different size (diameter).

In particular, in a rotary label mounting apparatus having a large number of label mounting heads having the above-described label expanding mechanism, all the circular disks must be replaced for each label mounting head. However, it takes a considerable amount of time to change the setup. In addition, since the number of annular disks to be prepared is considerably increased, there is a problem that the cost of parts is increased and a place for storing the parts must be secured.

Accordingly, an object of the present invention is to provide a size (diameter).
It is an object of the present invention to provide a label expanding mechanism capable of accommodating a plurality of different stretch labels and a label mounting device provided with the label expanding mechanism.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an opening / closing claw for expanding a stretch label inserted in a closed state by opening the same, and the opening / closing claw. A drive means for opening and closing the drive means, wherein the drive means extends from a small diameter concentric circle corresponding to the closed position to a large diameter concentric circle corresponding to the open position while extending in the rotational direction. A rotating body having a cam groove formed therein, and a cam follower attached to the opening and closing claw, the cam follower fitted into the cam groove, and rotating the rotating body in the forward and reverse directions to reduce the diameter of the cam follower. By moving between the concentric circle and the large diameter concentric circle, the label expanding mechanism that opens and closes the open / close claw between an open position and a closed position,
A stop area of the opening / closing claw, which extends along a concentric circle having a medium diameter around the rotation center of the rotating body, is set at an intermediate position of the cam groove. When a plurality of pairs of open / close claws having different opening / closing directions are provided, a “small-diameter concentric circle” corresponding to the closing position and a “large-diameter concentric circle” corresponding to the opening position are defined for all the opening / closing claws. It does not mean a common concentric circle, but if the closing position and the opening position are different for each pair of opening and closing claws, there are multiple concentric circles with different diameters for each pair of opening and closing claws. Become. In other words, the term "small diameter concentric circle" or "large diameter concentric circle" is present for each opening / closing claw, and includes those having different opening / closing strokes for each opening / closing claw.

In the label expanding mechanism configured as described above, the opening / closing claw can be opened and closed between one end and the other end of the cam groove, or the one end of the cam groove can be connected to the middle by simply changing the rotation angle of the rotating body. The open / close claw can be opened and closed between the stop area set at the position and the open / close claw can be opened and closed between the stop area set at the middle position of the cam groove and the other end. It is possible to accommodate at least three types of stretch labels (two types of diameters at the opening position) having different sizes (diameters) and elasticity without exchanging the labels themselves.

Since the stop area set at the intermediate position of the cam groove necessarily has a certain distance (length), it is not necessary to set the rotation angle of the rotating body with higher accuracy than necessary. In most cases, the cam follower stops within the stop area, and the stop position of the open / close claw does not slightly shift every time the open / close operation is performed.

Particularly, in the case where the plurality of stop regions are set at intermediate positions of the cam grooves as in the label expanding mechanism according to the second aspect, three or more types of stretches having different sizes (diameters) are provided. Since it is possible to respond to labels,
Further, there is an effect that versatility is enhanced.

Therefore, by installing the above-described label expanding mechanism on the label mounting device, the setup change when the stretch label is changed can be easily performed in a short time, and the replacement part can be replaced. There is an effect that it can be minimized.

[0014]

Embodiments will be described below with reference to the drawings. FIG. 1 shows a label mounting system 1 for mounting a tubular stretch label (hereinafter, referred to as a label) L formed of an elastic stretch film made of a polyethylene resin on a PET bottle (hereinafter, referred to as a bottle) B. This label mounting system 1 is
The label is supplied while sequentially cutting the long label forming base material M fed from the base roll by the base feeding unit 3a and the bottle feeding device 2 including the belt conveyor 7, the star wheel 2a, the screw conveyor 2b, and the star wheel 2c. L, and a label supply device 3 for sequentially supplying the label L to the first label delivery position α, and a second label supply device 3 for receiving the label L supplied to the first label delivery position α by the label supply device 3 and receiving the second label L. And the label delivery device 4 that conveys the bottle B supplied from the bottle supply device 2 at the bottle supply position γ, conveys the bottle B to the bottle delivery position δ, and is conveyed by the label delivery device 4. The received label L is received at the second label delivery position β, and the bottle B is moved from the bottle supply position γ to the bottle delivery position δ. A rotary type label mounting device 5 for mounting the label L on the bottle B while transporting the label L to the bottle B;
The label loading device 5 is configured to carry out the bottle B on which the label L is loaded, and comprises a bottle transport device 6 including a star wheel 6a, a screw conveyor 6b, and a belt conveyor 7.

The label-forming base material M is a bottle B
Are continuously connected to each other, and are wound around a drum in a state of being folded into a sheet shape in the base material feeding portion 3a. Also, the base material feeding section 3
The sheet-like label-forming base material M fed out from the a is folded back in the middle of the supply so that the folding position can be changed so that the label L can be easily opened again when the label L is attached to the bottle B. (See FIG. 1).

As shown in FIGS. 1 and 2, the label mounting device 5 is provided with a plurality of support arms 11 and 12 projecting radially from a rotating shaft (not shown) to form a concentric circle about the rotating shaft. A plurality of label mounting heads 10 are provided at regular intervals on the top, and each label mounting head 1
0, the tubular label L folded into a sheet and received at the second label transfer position β is expanded larger than the outer diameter of the bottle B, and the expanded label L is
The bottle B received at the bottle supply position γ is mounted on the body of the bottle B while being conveyed to the bottle delivery position δ.

The label mounting head 10 expands the cylindrical label L received in the second label transfer position β and folded into a sheet shape at a label mounting level to be larger than the outer diameter of the bottle B. Means 20, and the bottle B placed on the elevator 43 at a position below the label mounting level at the bottle supply position γ, by raising the elevator 43 to the label L expanded at the label mounting level. And a bottle elevating means 40 to be inserted.

As shown in FIG. 2, the label opening means 20 holds the label L folded into a sheet delivered and received by the label delivery device 4 at a position immediately above the bottle B placed on the elevator 43. It comprises a label opening mechanism 21 that receives and opens in a cylindrical shape, and a label expanding mechanism 25 that expands the label L opened by the label opening mechanism 21 to be larger than the outer diameter of the bottle B by an opening / closing claw. The label expanding mechanism 25 is fixedly installed at the label mounting level by the support arm 11, and the label opening mechanism 21 is disposed at a position directly above the label expanding mechanism 25 so as to be able to move up and down.

As shown in FIGS. 2 to 5, the label opening mechanism 21 includes a pair of clamp members 22 which can be opened and closed.
A suction unit (not shown) that causes the clamp member 22 to suction-hold both sides of the label L held by the clamp member 22 by sucking from a suction port formed in the holding unit 22a of the clamp member 22; Opening / closing drive means 23 for opening / closing and a lifting / lowering means 24 for raising / lowering the clamp member 22. The label opening mechanism 21 is capable of holding the label L folded into a sheet shape conveyed by the label delivery device 4. In the second label transfer position β, the label L is received by being clamped by the clamp member 22 and the label L is moved by the operation of the suction means.
The label L is opened in a cylindrical shape by opening the clamp member 22 and separating both sides of the label L from each other while the both sides of the label L are sucked and held by the holding portion 22a.

It should be noted that the label delivery device 4 is similar to that shown in FIGS.
As shown in the figure, a "U" -shaped label suction unit that suctions one side of the sheet-shaped label L to the tip of an arm that rotates so as to pass through the first label transfer position α and the second label transfer position β. The label L is delivered when the holding portion 22a of the clamp member 22 holds the label L sucked by the label suction portion 4a and separates the label L from the label suction portion 4a.

The opening / closing drive means 23 is shown in FIGS.
As shown in FIG. 5, a spring 23a that constantly biases the clamp member 22 in the closing direction, a pair of rollers 23b attached to the base end side of the clamp member 22, and a lower end portion,
An operating rod 23c to which a cam member 23d having a cam surface that comes into contact with both rollers 23b by being inserted between the rollers 23b is attached.
As shown in FIG. 2, a cam follower 23e fitted into a cam groove (not shown) is attached to the upper end of the arm through an attachment arm 23f.

The opening / closing drive means 23 constructed as described above
Then, as shown in FIG. 5B, when the cam follower 23e is lowered by the cam groove, the operating rod 23
When c is lowered and the cam member 23d attached to the lower end of the operating rod 23c pushes and spreads the roller 23b, the clamp member 22 is opened. Therefore, the clamp member 22 is opened and closed by moving the operation rod 23c up and down by a cam mechanism including the cam groove and the cam follower 23e.

The elevating means 24 is, as shown in FIG.
An operating rod 24a movably supported by the support arm 12 and a clamp member 2 provided at a lower end of the operating rod 24a.
2 and a cam follower 24c fitted into a cam groove (not shown) attached to the upper part of the operating rod 24a via a mounting arm 24d. The cam mechanism includes a cam groove and a cam follower 24c. The clamp member 22 is moved up and down by moving the operating rod 24a up and down.

The label expanding mechanism 25 is shown in FIGS.
As shown in FIG. 3, an annular disk 26 having a cam groove 27 rotatably supported by the support arm 11, and the annular disk 26
A sliding member 28 slidably supported in the radial direction of
An opening / closing claw 29 for expanding the label L fixed to the sliding member 28 is provided. The lower end of the inserted label L abuts on the opening / closing claw 29 to position the label L. Steps 29a are formed respectively.

A cam follower 30 which fits into a cam groove 27 formed in an annular disk 26 is attached to the sliding member 28, and the cam groove 27 has an annular shape as shown in FIGS. A large-diameter concentric circle C2 corresponding to the open position while extending in the rotational direction from a small-diameter concentric circle C1 corresponding to the closed position centered on the rotation center of the disk 26.
Up to an intermediate position, extending along a concentric circle C3 of a medium diameter centered on the rotation center of the annular disk 26.
A stop area 27a for the opening / closing claw 29 is formed.

Therefore, as shown by an arrow in FIG. 7, when the circular disk 26 rotates, the cam groove 27 formed in the circular disk 26 moves, so that the cam follower 30 moves between the concentric circles C1 and C2. Accordingly, the opening / closing claw 29 moves between the open position (see FIG. 7) and the closed position (see FIG. 8).

In this embodiment, the cam follower 3
Although the annular disk 26 is rotated by about 90 degrees so as to move 0 over the entire length of the cam groove 27, depending on the size (diameter) of the label L to be expanded, the concentric circle C1 and the concentric circle C3 may be displaced. By rotating the annular disk 26 so that the cam follower 30 moves between them, the state shown in FIG. 8 can be used as a closed state, the state shown in FIG. 9 can be used as an open state, and the concentric circle C3 can be used. By rotating the annular disk 26 so that the cam follower 30 moves between the concentric circles C2, the state shown in FIG. 9 can be used as a closed state, and the state shown in FIG. 7 can be used as an opened state.

Also, on the outside of the annular disk 26, FIG.
As shown in FIG.
A shaft 32 is rotatably supported through the shaft 3.
2, a gear 33 meshing with teeth formed on the outer peripheral surface of the annular disk 26 and an arm 34 having a cam follower 35 attached to the tip are fixed. The cam follower 35
It fits into a cam groove 36 formed in an annular plate material arranged along the rotation trajectory of the mounting head 10.

Therefore, the cam groove 36 and the cam follower 35
When the arm 34 swings by the cam mechanism, the gear 33 fixed to the shaft 32 rotates, and accordingly, the annular disk 26 meshed with the gear 33 rotates. The two pairs of opening / closing pawls 29 are opened and closed in the radial direction of the annular disk 26 by a cam mechanism including a cam groove 27 and a cam follower 30.

As shown in FIG. 2, the bottle elevating means 40 is mounted on an operating rod 41 supported by the support arm 12 so as to be vertically movable, and is attached to a lower end of the operating rod 41 via a mounting arm 42. , A lift 43 for mounting the bottle B, and a cam follower 45 fitted in a cam groove (not shown) mounted on the operating rod 41 via a mounting arm 44.
By moving the operating rod 41 up and down by a cam mechanism including a cam groove and a cam follower 45, the lift 43 is moved up and down.

The bottle elevating means 40 lowers the bottle B on the elevating platform 43 while lowering the elevating platform 43 while the bottle B is placed, in conjunction with the lowering operation of the elevating platform 43. The operating means 46 is supported by the support arm 12 so as to be vertically movable, and is attached to a lower end of the operating rod 46.
A head holder 47 fitted into the head of the bottle B;
6, which was attached to the center of attachment 6 via an attachment arm 48.
A cam follower 49 fits into a cam groove (not shown), and the head holder 47 is moved up and down by moving the operating rod 46 up and down by a cam mechanism including the cam groove and the cam follower 49.

The label mounting apparatus 5 configured as described above
First, as shown in FIG. 1, the clamp member 22 receives the cylindrical label L folded into a sheet and conveyed to the label transfer position β by the label transfer device 4. However, at the position immediately before the second label transfer position β, as shown in FIGS. 10A and 10B, the mounting head 10 is positioned above the opening / closing claw 29 fixedly installed at the label mounting level. The holder 47 and the clamp member 22 are located respectively, as shown in FIG.
As shown in (b), while the mounting head 10 approaches the label delivery position β, the clamp member 22 is gradually closed and the opening / closing claw 29 is also closed, as shown in FIG.
At the label transfer position β, the clamp member 22
, The label L is received from the label delivery device 4, and the label L is transported to the position just before the bottle sending position δ in that state (see FIG. 4D). At this time, as shown in FIGS. 9A to 9D, the bottle B on which the label L has been attached in the previous process is placed on the elevating table 43, as shown in FIG. Thus, at the bottle sending position δ, the bottle B on which the label L is attached is delivered to the bottle transport device 6.

When the clamp member 22 holding the label L is opened, as shown in FIG.
After the label L is opened in a cylindrical shape, the clamp member 22 and the head holder 47 are gradually lowered, and as shown in FIG.
1 (f)), at the bottle supply position γ,
The label L opened in a cylindrical shape (elliptical shape) is fitted into the open / close claw 29 in the closed state, and a new bottle B delivered from the bottle supply device 2 is placed on the elevating platform 43.

Next, as shown in FIG. 11 (g), the head holder 47 descends, and the head holder 47 pushes down the label L inserted into the opening / closing claw 29, thereby opening and closing the lower end of the label L. The label L abuts on the step 29a of the claw 29, and the label L is reliably positioned at the label mounting level, and the lift 43 on which the bottle B is placed starts to rise. When the label L is positioned by the head holder 47, the suction of the clamp member 22 is released, and at the same time, the clamp member 22 is slightly opened to release the suction of the label L by the clamp member 22. It is in a state of being left.

When the label L is positioned at the label mounting level in this way, as shown in FIG. 3H, the opening and closing claw 29 is opened, and the label L is expanded at the label mounting level. At the same time, the head holder 47 slightly rises and waits. When the label L is expanded at the label mounting level, the clamp member 22 is slightly closed to press and hold the label L against the opening / closing claw 29, and as shown in FIG. The bottle B rising by the table 43 is inserted into the expanded label L, and the head of the bottle B fits into the head holder 47.

In this state, since the upper end of the label L above the opening / closing claw 29 is in close contact with the outer peripheral surface of the body of the bottle B, it is shown in FIG. 12 (j) (FIG. 12 (j)). As described above, once the grip of the label L by the clamp member 22 is released, the clamp member 22 rises, and the upper end of the label L in close contact with the bottle B is gripped again together with the bottle B, so that the label L is B.

Then, as shown in FIG. 12 (k), the lifting table 43, the head holder 47 and the clamp member 22 are raised together, so that the clamp member 22 transfers the label L to the bottle B.
The label L is completely attached to the bottle B when the bottle B is once lifted in the state where the label L is held, and the opening and closing claws 29 are removed from the label L to release the spread of the label L.

Here, when the clamp member 22 is opened, the holding of the label L with respect to the bottle B is released, and as shown in FIG.
Drop together, the bottle B with the label L attached
After being retracted from the label mounting level,
Rises and returns to the original position shown in FIG. 10A, and the bottle B with the label L attached thereto is delivered to the bottle conveying device 6 at the bottle sending position δ as described above.

As described above, the label expanding mechanism 25 employed in the label mounting apparatus 5 has the stop area of the opening / closing claw 29 in advance at the intermediate position of the cam groove 27 constituting the cam mechanism for driving the opening / closing claw 29. 27a, the cam follower 30 extends over the entire length of the cam groove 27 as described above.
, The opening / closing claw 29 can be opened / closed with a large stroke, and the cam follower 30 is provided at one end or the other end of the cam groove 27 starting from the stop area 27a.
By moving the opening / closing claw 29, the opening / closing claw 29 can be opened / closed with a small stroke on the closing side or the opening side when the opening / closing claw 29 is largely opened / closed. Thus, it is possible to expand at least three types of labels L having different sizes (diameters) and elasticity only by changing the rotation angle of the annular disk 26.

In the label expanding mechanism 25, the stop area 27a set at an intermediate position of the cam groove 27 has a certain length (about 1.5 to 2 times the diameter of the cam follower 30). Therefore, when the cam follower 30 is moved with the stop area 27a as a starting point, usually, even if the rotation angle of the annular disk 26 is not set more accurately than necessary,
The cam follower 30 does not come off the stop area 27a, and the opening / closing claw 29 can be reliably stopped at a predetermined position corresponding to the stop area 27a.

Accordingly, in the label mounting apparatus 5 having such a label expanding mechanism 25, the three types of opening / closing patterns as described above can be obtained only by changing the rotation angle of the annular disk 26 by changing the cam groove 36. Can open and close the opening / closing claw 29, and if it conforms to the opening / closing pattern, a plurality of kinds of labels L can be opened without replacing the annular disk 26 having the cam groove 27, so that And the setup can be easily and simply changed in a short time when the label L is changed.
Replacement parts can also be kept to a minimum.

In this embodiment, only one stop area 27a is set at an intermediate position of the cam groove 27.
It is also possible to set a plurality of stop areas at an intermediate position of the cam groove 27. By doing so, it is possible to cope with three or more types of labels having different sizes (diameters), so that versatility is further improved. It has the effect of increasing.

Further, in this embodiment, as shown in FIG. 8, both ends of each cam groove 27 are all closed so that the two pairs of opening / closing claws 29 are all located on the same concentric circle in the closed state or the opened state. Although they are located on the same concentric circles C1 and C2,
The present invention is not limited to these.For example, one end of a cam groove that opens and closes the other pair of opening and closing claws so that another pair of opening and closing claws enter the inside of the pair of opening and closing claws in the closed state. By extending the cam groove for opening and closing the pair of opening / closing claws further inward than one end thereof, the opening / closing stroke of each pair of opening / closing claws is changed to reduce the area of the area surrounded by the closed opening / closing claws. It is also possible.

In this embodiment, the case where the stretch label is attached to the PET bottle has been described.
The object to be mounted is not limited to the PET bottle as described above, and the label opening mechanism and the label mounting device of the present invention are used when mounting a stretch label on various containers or cylindrical bodies such as bottles, cans, and the like. Can be applied to

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a label mounting system including one embodiment of a label mounting apparatus according to the present invention.

FIG. 2 is a schematic view showing a label mounting head of the label mounting apparatus according to the first embodiment.

FIG. 3 is a sectional view showing a label opening mechanism in the label mounting head according to the first embodiment.

FIG. 4 is a plan view showing a clamp member in the label opening mechanism of the above.

FIG. 5 is a side view showing opening and closing driving means for the clamp member.

FIG. 6 is a cross-sectional view showing a label expanding mechanism in the label mounting head of the above.

FIG. 7 is a plan view showing the internal structure of the above label expanding mechanism.

FIG. 8 is a schematic diagram showing a state in which the opening and closing claw is closed in the label opening mechanism of the above.

FIG. 9 is a schematic diagram showing a state in which the opening / closing claw is at an intermediate position between the open position and the closed position in the label expanding mechanism of the above.

FIG. 10 is an operation explanatory view showing a label mounting operation of the label mounting apparatus.

FIG. 11 is an operation explanatory view showing a label mounting operation of the above label mounting apparatus.

FIG. 12 is an operation explanatory view showing a label mounting operation of the above label mounting apparatus.

FIG. 13 is a schematic configuration diagram showing a conventional label expanding mechanism.

FIG. 14 is a schematic configuration diagram showing a state in which the opening and closing claw is closed in the label opening mechanism of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Label mounting system 5 Label mounting device 10 Label mounting head 20 Label expanding means 25 Label expanding mechanism 26 Annular disk 27 Cam groove 27a Stop area 29 Opening / closing claw 30 Cam follower B Bottle L Stretch label

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Kondo 1-5 Ishiharacho, Sakai-shi, Osaka F-Asterec Co., Ltd. F-term (reference) 3E095 AA07 BA01 DA01 DA31 DA41

Claims (3)

[Claims] An opening / closing claw that expands by opening a stretch label fitted and inserted in a closed state, and driving means for opening and closing the opening / closing claw, wherein the driving means has a rotation center as a center. And a rotating body formed with a cam groove extending from a small diameter concentric circle corresponding to the closing position to a large diameter concentric circle corresponding to the opening position while extending in the rotational direction, and attached to the opening / closing claw, respectively. A cam follower fitted into the cam groove, by rotating the rotating body in the forward and reverse directions to move the cam follower between the small diameter concentric circle and the large diameter concentric circle, In the label expanding mechanism configured to open and close the opening / closing claw between an opening position and a closing position, the cam groove has a middle diameter concentric circle centered on a rotation center of the rotating body at an intermediate position thereof. Along A label expansion mechanism, wherein a stop area of the opening / closing claw is set to extend. 2. The label expanding mechanism according to claim 1, wherein a plurality of the stop areas are set at an intermediate position of the cam groove. 3. A label mounting device provided with the label expanding mechanism according to claim 1.