Chain tensioner, machine for processing elements in the form of sheets and method for tensioning the chain sets

Patent metadata

Field	Value
Publication number	US-10753434-B2
Application number	US-201716080695-A
Country	US
Kind code	B2
Filing date	Mar 9, 2017
Priority date	Mar 9, 2016
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

A chain tensioner ( 50; 500 ) for a conveying device ( 70 ) of a machine ( 1; 1 ′) for processing elements in the form of sheets ( 10 ), the conveying device ( 70 ) includes two lateral chain sets connected to the ends of transverse gripper bars ( 75 ) able to grasp the elements ( 10 ) and at least one chain-guiding device ( 90 ) configured to guide a respective chain set ( 80 ); the chain tensioner ( 50; 500 ) includes: an actuator ( 9 ) controlled by a control unit ( 8 ), a movable support ( 11 ), a transmission element ( 12 ) borne by the movable support ( 11 ), a rotary element ( 13 ) rotated by the actuator ( 9 ) and cooperating with the transmission element ( 12 ) in order to exert a thrust force on the movable support ( 11 ), the rotary element ( 13 ) being rotatable, to adjust the tension of the chain set ( 80 ). The actuator ( 9 ) is controlled in synchronism with the machine angle (MA). A machine ( 1; 1 ′) for processing elements and a method for tensioning the chain sets ( 80 ) of the conveying device ( 70 ) are disclosed.

First claim

The invention claimed is:

1. A chain tensioner for a conveying device of a processing machine for processing elements in the form of sheets, the conveying device comprising:
a plurality of transversely extending gripper bars;
two lateral chain sets connected to respective ends of the plurality of transverse gripper bars;
grippers on the gripper bars, the grippers being configured to grasp the elements in the form of sheets;
at least one chain-guiding device configured to guide a respective chain set;
the chain tensioner comprising:
an actuator configured to be controlled by a control unit of the processing machine;
a movable support, a transmission element borne by the movable support; and
a rotary element configured to be rotated by the actuator and to cooperate with the transmission element in order to exert a thrust force on the movable support, the rotary element being rotatable over an angular range (α) of less than 360° between a first extreme angular position and a second extreme angular position,
wherein a tension of the chain set is minimum for the first extreme angular position and maximum for the second extreme angular position, the actuator being controlled in synchronism with a machine angle.

2. A chain tensioner according to claim 1 , wherein the transmission element comprises a cam roller mounted rotatably on the movable support,
the rotary element comprises a cam, the cam having a cam surface configured to cooperate with a surface of the cam roller, the cam surface having a volute shape including a radius that increases between the first extreme angular position and the second extreme angular position.

3. A chain tensioner according to claim 1 , wherein the transmission element borne by the movable support includes a link, the link having one end mounted pivotably on the movable support and another end mounted pivotably on the rotary element.

4. A chain tensioner according to claim 1 , further comprising the angular position of the rotary element is also controlled as a function of a machine production rate.

5. A chain tensioner according to claim 1 , further comprising the control unit is configured to define the position of an operating angle (β) within the angular range (α) in order to take account of environmental parameters of the chain sets.

6. A chain tensioner according to claim 1 , further comprising:
the actuator comprises a drive shaft; and
the rotary element is in direct engagement with the drive shaft of the actuator.

7. A chain tensioner according to claim 1 , wherein an operating angle (β) of the rotary element over which the rotary element cooperates with the transmission element over a machine cycle is greater than 0° and less than 100°.

8. A chain tensioner according to claim 1 , wherein the movable support comprises a pivotable rocker configured to be articulated with the chain-guiding device.

9. A chain tensioner according to claim 8 , wherein the pivotable rocker comprises:
a bar;
a pivot configured to be fixed to a frame of the processing machine and on which a first end of the bar is mounted,
a ball joint configured to cooperate with the chain-guiding device and with a second end of the bar; and
a head fixed to the bar, the transmission element being mounted movably in one end of the head.

10. A chain tensioner according to claim 1 , wherein the movable support comprises a translationally movable carriage.

11. A chain tensioner according to claim 1 , further comprising at least one return device configured to apply a substantially constant thrust force to the chain-guiding device.

12. A machine for processing elements in the form of sheets, comprising:
a plurality of machine workstations;
a conveying device for conveying each sheet successively through various workstations, the conveying device comprising:
a plurality of transverse gripper bars extending transversely to a path of the conveying device;
at least one gripper on each of the gripper bars, the grippers being configured to grasp the sheets by their front edges;
first and second lateral chain sets connected to respective ends of the gripper bars;
at least one chain-guiding device configured to guide a respective chain set; and
the processing machine comprising at least one chain tensioner according to claim 1 configured to tension at least one of the chain sets.

13. A processing machine according to claim 12 , further comprising two of the chain tensioners configured to tension a respective chain set.

14. A method for tensioning chain sets of a conveying device of a machine for processing elements in the form of sheets by action of at least one chain tensioner according to claim 1 , in which an angular position of the rotary element between the first extreme angular position and the second extreme angular position is controlled in synchronism with the machine angle (MA);
the method comprising:
rotating the rotary element in one direction selected for increasing the tension of the chain set, and rotating the rotary element in an opposite direction of rotation selected for decreasing the tension of the chain set.

15. A method according to claim 14 , further comprising:
controlling a motor of the actuator in terms of current position.

16. A method according to claim 14 , further comprising controlling the actuator as a function of the machine production rate.

17. A method according to claim 14 , further comprising defining a position of an operating angle (α) within the angular range (β) in order to take account of environmental parameters of the chain sets.

18. A method according to claim 14 , further comprising starting control of the angular position of the rotary element in synchronism with the machine angle (MA) only when the machine production rate is above a machine production rate threshold.

19. A method according to claim 14 , further comprising controlling the angular position of the rotary element in a disengaged position of the transmission element in order to apply a substantially constant thrust force of a return device only to the chain-guiding device.

Assignees

• Bobst Mex Sa

Inventors

• Ruchet Christophe

Classifications

• B65H29/04 Primary

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• B65H2701/1764

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