Methods for transferring discrete articles

1. A method of transferring discrete articles from a pick-up location to a drop-off location, the method comprising:

providing a transfer device having a frame defining a rotation axis, wherein the transfer device comprises a plurality of transfer heads;

circumnavigating the plurality of transfer heads about the rotation axis in an orbit, wherein the orbit passes through the pick-up location and the drop-off location;

providing a web accumulation device proximate to the drop-off location, wherein the web accumulation device is configured to convey a web;

moving the web through the web accumulation device at a variable speed;

using one of the plurality of transfer heads to pick up a discrete article at the pick-up location;

carrying the discrete article on the one of the plurality of transfer heads between the pick-up location and the drop-off location; and

placing the discrete article onto a portion of the web in the drop-off location at a first discrete article pitch and when the portion of the web is moving at a first speed.

2. The method of claim 1 , comprising:

using a second one of the plurality of transfer heads to pick up a second discrete article at the pick-up location;

carrying the second discrete article on the second one of the plurality of transfer heads between the pick-up location and the drop-off location; and

placing the second discrete article onto a second portion of the web in the drop-off location at the first discrete article pitch, wherein the two placing steps occur substantially simultaneously.

3. The method of claim 1 , comprising:

using a second one of the plurality of transfer heads to pick up a second discrete article at the pick-up location;

carrying the second discrete article on the second one of the plurality of transfer heads between the pick-up location and the drop-off location; and

placing the second discrete article onto a second portion of the web in the drop-off location at the first discrete article pitch, wherein the two placing steps occur sequentially.

4. The method of claim 1 , comprising:

using a second one of the plurality of transfer heads to pick up a second discrete article at the pick-up location;

carrying the second discrete article on the second one of the plurality of transfer heads between the pick-up location and the drop-off location; and

placing the second discrete article onto a second portion of the web in the drop-off location at a second discrete article pitch and when the second portion of the web is moving at a second speed, wherein the second discrete article's dimensions are different than the first discrete article's dimensions.

5. The method of claim 4 , wherein the second speed is different than the first speed.

6. The method of claim 4 , comprising:

maintaining a first length of the web in the web accumulation device for the first discrete article pitch; and

maintaining a second length of the web in the web accumulation device for the second discrete article pitch;

wherein the first length is different than the second length.

7. The method of claim 1 , comprising substantially matching the speed of the web with the speed of the transfer head during the placing step.

8. The method of claim 1 , comprising rotating the plurality of transfer heads between a first position and a second position intermediate the pick-up location and the drop-off location.

9. The method of claim 8 , wherein the rotating comprises rotating the head about 90 degrees about an axis perpendicular to the rotation axis.

10. The method of claim 1 , comprising repitching the discrete articles intermediate the pick-up location and the drop-off location.

11. The method of claim 1 , comprising applying a fluid pressure to the plurality of transfer heads.

12. The method of claim 1 , comprising conveying the web into and out of the web accumulation device at a constant velocity.

13. A method of transferring discrete articles from a pick-up location to a drop-off location, the method comprising:

providing a transfer device having a frame defining a rotation axis, wherein the transfer device comprises a plurality of transfer heads;

circumnavigating the plurality of transfer heads about the rotation axis in an orbit, wherein the orbit passes through the pick-up location and the drop-off location;

providing a web accumulation device at least partially in the drop-off location, wherein the web accumulation device is configured to convey a web;

moving the web through the web accumulation device at a variable speed;

using a first transfer head to pick up a first discrete article at the pick-up location;

carrying the first discrete article on the first transfer head between the pick-up location and the drop-off location;

using a second transfer head to pick up a second discrete article at the pick-up location;

carrying the second discrete article on the second transfer head between the pick-up location and the drop-off location;

first placing the first discrete article onto a first portion of the web in the drop-off location at a first discrete article pitch and when the first portion of the web is moving at a first speed; and

substantially simultaneously with the first placing step, second placing the second discrete article onto a second portion of the web in the drop-off location at the first discrete article pitch and when the second portion of the web is moving at the first speed.

14. The method of claim 13 , comprising:

substantially matching the speed of the first portion of the web with the first transfer head during the first placing step; and

substantially matching the speed of the second portion of the web with the second transfer head during the second placing step.

15. The method of claim 13 , comprising rotating the first transfer head between a first position and a second position intermediate the pick-up location and the drop-off location, wherein the rotating comprises rotating the transfer head about 90 degrees about an axis perpendicular to the rotation axis.

16. The method of claim 13 , comprising:

conveying the web into and out of the web accumulation device at a constant velocity; and

applying a fluid pressure to the first and second transfer heads.

17. The method of claim 13 , comprising repitching the first and second discrete articles intermediate the pick-up location and the drop-off location.

18. A method of transferring discrete articles from a pick-up location to a drop-off location, the method comprising:

providing a transfer device having a frame defining a rotation axis, wherein the transfer device comprises a plurality of transfer heads;

circumnavigating the plurality of transfer heads about the rotation axis in an orbit, wherein the orbit passes through the pick-up location and the drop-off location;

providing a web accumulation device at least partially in the drop-off location, wherein the web accumulation device is configured to convey a web;

moving the web through the web accumulation device at a variable speed;

using the plurality of transfer heads to pick up first discrete articles at the pick-up location, wherein the first discrete articles have a first discrete article size;

carrying the first discrete articles on the plurality of transfer heads between the pick-up location and the drop-off location;

placing the first discrete articles onto a portion of the web in the drop-off location at a first discrete article pitch and when the portion of the web is moving at a first speed;

subsequently, the method comprises:

using the plurality of transfer heads to pick up second discrete articles at the pick-up location, wherein the second discrete articles have a second discrete article size, and wherein the first discrete article size is different than the second discrete article size;

carrying the second discrete articles on the plurality of transfer heads between the pick-up location and the drop-off location; and

placing the second discrete articles onto a portion of the web in the drop-off location at a second discrete article pitch and when the portion of the web is moving at a second speed, wherein the second discreet article pitch is different than the first discrete article pitch.

19. The method of claim 18 , comprising rotating the transfer heads between a first position and a second position intermediate the pick-up location and the drop-off location, wherein the rotating comprises rotating the transfer heads about 90 degrees about an axis perpendicular to the rotation axis.

20. The method of claim 18 , comprising:

applying a fluid pressure to the transfer heads; and

repitching the first and second discrete articles intermediate the pick-up location and the drop-off location.