Patent Grant
12029630
The present invention relates to an apparatus and method for manufacturing absorbent articles, and particularly to conveying workpieces.
With conventional methods, when conveying a workpiece of an absorbent article, the holding pad picks up the workpiece at the pick-up position, thereafter accelerates or decelerates, and then hands over the workpiece onto the sheet at the hand-over position. With the apparatus disclosed in the first patent document identified below, a plurality of hand-over positions are provided, and the velocity of the holding pad is varied depending on the size of the article to be manufactured.
[FIRST PATENT DOCUMENT] JP2010-142414 A (FIG. 5)
Typically, a velocity-changing cam mechanism is employed to accelerate/decelerate the velocity of the holding pad. However, with the invention of the first patent document, the holding pad is at a constant velocity at the two hand-over positions. Thus, there are a plurality of constant-velocity regions, which is a factor for imposing a large load on the cam mechanism.
Such an issue will be described in detail with reference to
Where workpieces are handed over onto the sheet at a plurality of positions, i.e., the upstream position and the downstream position, there are two constant-velocity periods T10 and T30 where the velocity of the holding pad is constant, as shown in
When such constant velocity and acceleration/deceleration are repeated, the cam mechanism is subjected to a load every cycle at points in time T, at which acceleration changes. This load lowers the durability of the cam mechanism, necessitating early maintenance.
While the velocity of the holding pad may be accelerated/decelerated by controlling the rotation speed of the servomotor, the load on the servomotor increase also in this case due to the plurality of constant-velocity regions.
Thus, it is an object of the present invention to provide an apparatus and method for manufacturing an absorbent article that can accommodate changes in the size of the article to be manufactured without imposing a large load on the equipment.
An apparatus of the present invention includes:
a holding pad that rotates along a circling path while velocity thereof is changed to pick up a workpiece at a pick-up position and hand over the workpiece onto a continuous sheet at a hand-over position;
a conveying device that conveys the continuous sheet at conveying velocity that depends on a size of a product to receive and convey the workpiece on the continuous sheet at the hand-over position; and
a velocity-changing device that changes velocity so that circumferential velocity V of the holding pad is continuously decelerated or continuously accelerated during a period from a first start time S1, at which hand-over of the workpiece for a first-size product at an upstream position as the hand-over position on the circling path is started, to a second start time S2, at which hand-over of the workpiece for a second-size product at the downstream position as the hand-over position downstream of the upstream position on the circling path is started.
A method of the present invention includes:
a first conveying step of using a holding pad that rotates along a circling path while velocity thereof is changed to pick up a workpiece at a pick-up position and hand over the workpiece onto a continuous sheet at a hand-over position;
a second conveying step of using a conveying device to convey the continuous sheet at conveying velocity VN that depends on a size of a product to receive and convey the workpiece on the continuous sheet at the hand-over position;
a step of setting in advance the hand-over position to be one position selected between an upstream position and a downstream position on the circling path, the downstream position being downstream of the upstream position, depending on the size; and
a velocity-changing step in which a velocity-changing device changes velocity so that circumferential velocity V of the holding pad is continuously decelerated or continuously accelerated during a period from a first start time S1, at which hand-over of the workpiece for a first-size product at the upstream position is started, to a second start time S2, at which hand-over of the workpiece for a second-size product at the downstream position is started.
According to the present invention, it is possible to select the upstream position and the downstream position so as to hand over the workpiece of the first or second size onto the conveying device at the respective positions. Therefore, it is possible to manufacture, with a single apparatus, articles of different sizes.
Particularly, during a period from the first start time S1 to the second start time S2, the velocity does not become a constant velocity but is continuously decelerated or accelerated. Therefore, it is possible to reduce the load on parts such as the cams and the servomotor.
Note that when manufacturing three or more sizes with a single apparatus, a position may be set for handing over a workpiece of the third size.
Preferably, the velocity-changing device 2 changes velocity so that the circumferential velocity V is continuously decelerated during a period from the first start time S1 to the second start time S2.
According to the present invention, the continuous sheet is conveyed at a generally constant velocity that depends on the size, whereas the pad circles at a non-constant velocity when handing over the workpiece. Therefore, when the workpiece is placed on the sheet while the pad is accelerating, the workpiece may likely be creased.
In contrast, when the workpiece is placed on the sheet while the pad is decelerating, the workpiece is likely to be stretched in the conveying direction and unlikely to be creased. Therefore, by handing over the workpiece while decelerating, the workpiece is likely to be neatly placed on the sheet, thereby facilitating bonding between the sheet and the workpiece.
Preferably, for the first size, the conveying velocity is set to the circumferential velocity V of the holding pad at the first start time S1; and
for the second size, the conveying velocity is set to the circumferential velocity V of the holding pad at the second start time S2.
In this case, when handing over the workpiece W onto the continuous sheet N, the workpiece W is unlikely to be creased.
Preferably, the velocity-changing device changes the velocity of the holding pad so that the circumferential velocity V is continuously decelerated or continuously accelerated over a first period T1 from the first start time S1 to a first completion time C1, at which hand-over of the workpiece of the first size is completed, a second period T2 from the first completion time C1 to the second start time S2, and a third period T3 from the second start time S2 to a second completion time C2, at which hand-over of the workpiece of the second size at the downstream position is completed.
In this case, the velocity is continuously decelerated or accelerated not only in the first and second periods T1 and T2 but also in the third period T3. Therefore, it is possible to further reduce the load on the parts.
Preferably, the apparatus further includes a setting device for setting the upstream position P1 or the downstream position P2 as the hand-over position.
More preferably, the conveying device includes a transfer roll that contacts the holding pad with the continuous sheet and the workpiece therebetween; and the setting device positions the transfer roll at one of the upstream position and the downstream position.
While the transfer roll may be provided at each of the upstream position and the downstream position, the transfer roll at the upstream position and the transfer roll at the downstream position are then arranged spaced apart from each other so as to avoid interference between the transfer rolls, and the degree of freedom in selecting the position is likely to be low.
In contrast, allowing the transfer roll to be moved between the upstream position and the downstream position and selectively fixed to the frame increases the degree of freedom in selecting the position. This increases the degree of freedom in selecting the circumferential velocity V at the time of hand-over at each position.
When the deceleration ratio is too large, the stretch of the workpiece will be excessive, whereas when the deceleration ratio is 1.0, i.e., constant velocity, the advantageous effects of the present invention will not be realized.
From such a viewpoint, when decelerating, preferably, a deceleration ratio of the circumferential velocity V at the second start time S2 relative to the circumferential velocity V at the first start time S1 is set to be greater than 1.0 and 1.2 or less, preferably 1.07 or less, and more preferably 1.01 or less.
When the acceleration ratio is too large, the workpiece will be creased, whereas when the acceleration ratio is 1.0, i.e., constant velocity, the advantageous effects of the present invention will not be realized.
From such a viewpoint, when accelerating, preferably, an acceleration ratio of the circumferential velocity V at the second start time S2 relative to the circumferential velocity V at the first start time S1 is greater than 1.0 and 1.2 or less, preferably 1.07 or less, and more preferably 1.01 or less.
Any feature illustrated and/or depicted in conjunction with one of the aforementioned aspects or the following embodiments may be used in the same or similar form in one or more of the other aspects or other embodiments, and/or may be used in combination with, or in place of, any feature of the other aspects or embodiments.
The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention shall be defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures.
Embodiments of the present invention will now be described with reference to the drawings.
First, prior to describing the present embodiment, an example of a worn article (absorbent article), which is an application thereof, will be described.
In this figure, worn articles are produced from a continuous sheet N and workpieces (absorbent bodies) W. The continuous sheet N is a nonwoven fabric with elastic members arranged along its longitudinal direction, for example, and there may be a pair of continuous sheets N.
Workpieces W are cut into units of articles from the continuous laminate W1, and then separated from the continuous laminate W1, after which they are turned 90° to be provided so as to bridge between a pair of continuous sheets N and N. The workpieces W provided so as to bridge between the continuous sheets are folded in two and then cut into units of worn articles N1.
Next, the outline of a present manufacturing apparatus will be described.
In
The holding pad 20 circles, while changing its velocity, along the circling path of the velocity-changing device 2, picks up the workpiece W from the hand-over roll 1 at the pick-up position P, and hands over the workpiece W onto the continuous sheet N at the hand-over position P1, P2. The hand-over positions include the upstream position P1 and the downstream position P2. The upstream position P1 or the downstream position P2 is the hand-over position for when the size of the worn article is the first size or the second size, respectively.
The conveying device 5 conveys the continuous sheet N at conveying velocity VN that depends on the size of the product to receive and convey the workpiece W on the continuous sheet N at the hand-over position P1 or P2. For example, the conveying velocity VN may be a high velocity V1S for the first size (size L), and may be a lower velocity V2S for the second size (size M). The conveying device 5 in this embodiment includes a transfer roll 50 and guide rolls 51 and 52 arranged upstream and downstream of the transfer roll 50, and conveys the continuous sheet N continuously from the upstream side to the downstream side.
The conveying device 5 includes a setting device 3 as shown in
Next, an example of the structure of the setting device 3 will be described using
In
On the other hand, the second movable frame 32 is attached to the first movable frame 31 so as to be movable, relative to the first movable frame 31, in the normal direction D2 of the circling direction R of the holding pad 20. The second movable frame 32 axially supports the transfer roll 50, and the transfer roll 50 can therefore be freely fixed at the upstream position P1 or the downstream position P2 or any other position.
Next, the velocity-changing device 2 of this embodiment will be described in detail.
As shown in
A velocity-changing cam roller 29 is provided at a position spaced apart from the arm center 28 of each crank arm 22. The cam rollers 29 move along a velocity-changing cam groove 44. The velocity-changing cam groove 44 is invariable and eccentric with a center of drive 210, which is the center of rotation of the driven wheel 21. Therefore, the distance from the center of drive 210 to the cam roller 29 periodically expands and contracts depending on the position of the cam roller 29 and the cam groove 44.
Therefore, the crank arm 22 swings periodically within a certain angular range, and the tip of the crank arm 22 swings periodically. That is, the tip of the crank arms 22 is displaced in the conveying direction along the circling direction R relative to the arm center 28 of the crank arm 22 on the left side shown in
A link lever 23 that is pin-linked to the tip of the crank arm 22 and a link block 24 that is pin-linked to the link lever 23 are displaced in conjunction with the swing of the tip of the crank arm 22. As the crank arm 22 swings, the distance between the arm center 28 of the crank arm 22 and the link block 24 changes, thereby also changing the interval between adjacent link blocks 24. As a result, this changes the angular velocity of the holding pad 20 linked to the link block 24 and the interval between the holding pads 20 and 20 in the circling direction R.
As shown in
After the hand-over action, the holding pad 20 turns while changing the velocity while the holding pad 20 circles in the circling direction R from the hand-over position P1 (P2), and the holding pad 20 circles to the pick-up position P, and picks up the workpiece W at the pick-up position P. Each holding pad 20 continuously performs these actions, thereby successively placing workpieces W of
Note that the mechanism by which the holding pad 20 of
The holding pad 20 sucks the workpiece W by negative pressure at the pick-up position P and then holds the workpiece W, and the holding pad 20 circles along the circling direction R and releases the negative pressure upstream of the hand-over position P1 (P2). On the other hand, the conveying device 5 activates negative pressure at the hand-over position P1, P2 to receive the workpiece W on the continuous sheet N.
When the upstream position P1 and the downstream position P2 are close to each other as in this embodiment, the area over which negative pressure is applied to the holding pad 20 may be constant. However, when the upstream position P1 and the downstream position P2 are distant from each other (JP2010-142414 A), the area may need to be varied.
Next, the velocity-changing device 2 and the velocity-changing step of
The hand-over position is set in advance to be one position selected between the upstream position P1 and the downstream position P2 on the circling path, the downstream position P2 being downstream of the upstream position P1, depending on the size. That is, for the first size (size L), the transfer roll 50 is fixed at the upstream position P1. On the other hand, for the second size (size M), the transfer roll 50 is fixed at the downstream position P2.
In
First start time S1: a point in time when the hand-over of the workpiece W for the first size at the upstream position P1 of
First completion time C1: a point in time when the hand-over of the workpiece W for the first size at the upstream position P1 of
First middle time M1: a point in time that is in the middle between the first start time S1 and the first completion time C1 (see
Second start time S2: a point in time when the hand-over of the workpiece W for the second size at the downstream position P2 of
Second completion time C2: a point in time when the hand-over of the workpiece W for the second size at the downstream position P2 of
Second middle time M2: a point in time that is in the middle between the second start time S2 and the second completion time C2 (see
In this embodiment, different periods T0 to T3 of FIG. 2(g) are defined as follows.
T0: a pre-start period before the first start time S1 of
T1: a first period from the first start time S1 to the first completion time C1.
T2: a second period from the first completion time C1 to the second start time S2.
T3: a third period from the second start time S2 to the second completion time C2.
In this embodiment, the velocity-changing device 2 changes the velocity of the holding pad 20 so that the circumferential velocity V of the holding pad 20 is continuously decelerated over the pre-start period T0, the first period T1, the second period T2 and the third period T3.
This deceleration (velocity changing) step will be described in detail.
For the first size, the transfer roll 50 of
For the first size, the holding pad 20 is similarly continuously decelerated also in the pre-start period T0, which is prior to the first period T1, the second period T2 and the third period T3.
For the second size, the transfer roll 50 of
For the second size, the holding pad 20 is similarly continuously decelerated also in the pre-start period T0, which is prior to the third period T3, the first period T1 and the second period T2.
Therefore, the holding pad 20 of
On the other hand, for the first size and the second size, the conveying velocity VN of the continuous sheet N by the conveying device 5 may be set to respective constant velocities of V1S and V2S.
That is, for the first size, the conveying velocity VN may be set to the circumferential velocity V of the holding pad 20 at the first start time S1, at which the hand-over of the workpiece W of the first size is started, i.e., V1S. In this case, during the hand-over step of
Similarly, for the second size, the conveying velocity VN may be set to the circumferential velocity V of the holding pad 20 at the second start time S2, at which the hand-over of the workpiece W of the second size is started, i.e., V2S. In this case, during the hand-over step of
While the circumferential velocity V is continuously decelerated over the periods T0 to T3 as shown in
As shown in
While this embodiment is directed to a case where worn articles of two sizes are manufactured, there may be three or more sizes.
When manufacturing worn articles of the first to third sizes, the transfer roll 50 may receive the workpiece W at the upstream position P1, the downstream position P2 and the most downstream position P3 as indicated by solid and two-dot-chain lines of
When the hand-over is done at the positions P1 to P3 for the first to third sizes, the velocity of the circumferential velocity V of the holding pad 20 may be decelerated as shown in
As described above, the holding pad 20 of
For example, as shown in the velocity diagram of
Now, the point in time when the negative pressure acts on the holding pad 20 may be changed in response to the change of the size. Note that when the positions P1 to P3 are as close to each other as shown in
Transfer rolls may be individually provided at the respective hand-over positions P1 and P2.
When two transfer rolls 50 of
Note that the transfer roll 50 of
While preferred embodiments have been described above with reference to the drawings, obvious variations and modifications will readily occur to those skilled in the art upon reading the present specification.
For example, the workpiece does not need to be rotated 90 degrees about the normal direction while the workpiece moves from the pick-up position to the hand-over position. The length in the circumferential direction of the holding pad at the hand-over position may be shorter than that at the pick-up position, or they may be equal to each other.
The velocity of the holding pad at the pick-up position may be a constant velocity from the start of the pick-up until the completion of the pick-up.
Thus, such variations and modifications shall fall within the scope of the present invention as defined by the appended claims.
The present invention is applicable to conveying during the manufacture of various absorbent articles such as disposable pants and diapers.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-247299 | Dec 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/044318 | 11/12/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/137206 | 7/2/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 7347914 | Umebayashi | Mar 2008 | B2 |
| 7438779 | Nakakado | Oct 2008 | B2 |
| 20050241751 | Nakakado | Nov 2005 | A1 |
| 20150223992 | Maehara | Apr 2015 | A1 |
| 20150272786 | Piantoni | Oct 2015 | A1 |
| 20160250080 | Wada | Sep 2016 | A1 |
| Number | Date | Country |
|---|---|---|
| 2612632 | Jul 2013 | EP |
| 3 395 309 | Oct 2018 | EP |
| 2002253606 | Sep 2002 | JP |
| 2010-142414 | Jul 2010 | JP |
| 2013255624 | Dec 2013 | JP |
| WO-2005085108 | Sep 2005 | WO |
| WO-2014060923 | Apr 2014 | WO |
| WO-2016170947 | Oct 2016 | WO |
| Entry |
|---|
| International Search Report for corresponding Application No. PCT/JP2019/044318, mailed Feb. 4, 2020. |
| Number | Date | Country | |
|---|---|---|---|
| 20220008256 A1 | Jan 2022 | US |
