The present invention relates generally to printing devices and more particularly to a web infeed device for rotary printing devices.
U.S. Pat. No. 5,967,036 describes a web infeed device for rotary printing presses, which permits a web to be fed through the printing press. A flexible, finite infeed element for holding a lead edge of a web runs in a guide or track. Balls are inserted in openings of the infeed element at spaced-intervals, and travel within a cross-cut in the guide. Drive elements can drive the balls and thus move the infeed element through the printing press to feed the web. U.S. Pat. No. 5,967,036 is hereby incorporated by reference herein. It has been known for the tip of the infeed element described therein to jam in the guide, for example in curves or gaps.
U.S. Pat. No. 5,320,039 discloses a web engagement system for an off-reel printing press in which a guide piece is accommodated in a guide channel. The guide piece preferably is a flexible plastic section with a square cross-section. The front part is tapered and a rear part is split.
U.S. Pat. No. 4,987,830 discloses a paper feed device for rotary presses having a spindle shaped linear member. The linear member is made of synthetic resin or leather, with caps being made of a rather hard material.
The devices of the '039 and '830 are long flexible members that ran in guides and contact the guides over a large length. The friction generated by flexible members passing over a curved section is subject to what is known as the capstan effect, which causes frictional forces to increase exponentially as the flexible member wraps around the surface.
An object of the present invention is to provide a web infeed device with reduced friction and improved feeding properties.
The present invention provides a web infeed device for rotary printing presses comprising an infeed element having a flexible section and a pointed nose piece having concave side portions; a guide, the flexible infeed element being received in the guide; and driving elements for driving the infeed element along the guide.
The nose piece of the present invention with the concave side portions provides for excellent feeding while reducing friction with the guide.
The flexible section preferably includes a flat band-shaped metal piece. The band-shaped piece may include holes, and balls located in the holes.
The pointed nose piece preferably is made of rigid material, and preferably has a cut out at a rear end for receiving the band-shaped metal piece.
A rear section of the nose piece preferably is curved, to aid in rearward movement of the infeed element.
Preferably, the nose piece is symmetrical about a longitudinal plane, preferably a plane defined by the flexible section. Most preferably, the nose piece is fully symmetrical about a longitudinal axis.
The present invention also provides a web infeed device for rotary printing presses comprising an infeed element having a flexible band-shaped section and a rigid pointed nose piece connected to the flexible band section; a guide, the flexible infeed element being received in the guide; and driving elements for driving the infeed element along the guide.
By using a rigid pointed nose piece in conjunction with the flexible band section, excellent feeding with reduced friction can be provided.
The present invention also provides a web infeed device for rotary printing presses comprising an infeed element having a first flexible section, a second flexible section and a connecting piece having concave side portions connecting the first flexible section to the second flexible section; a guide, the flexible infeed element being received in the guide; and driving elements for driving the infeed element along the guide.
Preferred embodiments of the present invention are described below by reference to the following drawings, in which:
As shown in
“Pointed” as defined herein means any tapered section, and can include a spherical or bulbous section.
The concave side portions of the present permit the nose piece to negotiate curves without creating excess friction, and also reduce friction during normal travel of the nose piece.
Number | Name | Date | Kind |
---|---|---|---|
4987830 | Fukuda et al. | Jan 1991 | A |
5320039 | Reponty et al. | Jun 1994 | A |
5809892 | Kruger et al. | Sep 1998 | A |
5947361 | Berger et al. | Sep 1999 | A |
5967036 | Marmin et al. | Oct 1999 | A |
6398094 | Alexander | Jun 2002 | B1 |
Number | Date | Country | |
---|---|---|---|
20040003731 A1 | Jan 2004 | US |