Advancing material of indeterminate length – Threading device – With means to pull lead-end
Reexamination Certificate
2000-01-11
2001-12-04
Mansen, Michael R. (Department: 3653)
Advancing material of indeterminate length
Threading device
With means to pull lead-end
C242S615210, C101S223000
Reexamination Certificate
active
06325266
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper-threading device for threading paper web along a paper-threading path, along which paper web travels during operation of a rotary press. More particularly, the invention relates to a paper-threading device for threading paper web along an angle-bar paper-threading path by means of moving a paper leader to which paper web is affixed, along a paper-leader guide provided along the angle-bar paper-threading path, which extends around angle bars while changing direction at each angle bar.
2. Description of the Related Art
A conventional automatic paper-threading device for use in an angle bar section of a rotary press is disclosed in, for example, Japanese Utility Model Publication (kokoku) No. 7-39646.
This automatic paper-threading device includes a guide pipe having a cross section shaped like the letter C and a paper-threading rope movably accommodated in the guide pipe. The guide pipe is provided along an angle-bar paper-threading path, which extends around angle bars while changing direction at each angle bar. A joint is attached to the paper-threading rope in such a manner as to be projected through a slit formed in the guide pipe. A paper web leader made from a film material is attached to the joint. A leading end portion of paper web is affixed to the paper web leader. The paper-threading rope is caused to travel through the guide pipe by means of a driving roller and an auxiliary roller, between which the paper-threading rope is held, thereby threading paper web along the angle-bar paper-threading path.
The paper-threading rope stands by at a position which is located upstream of the angle-bar paper-threading path and downstream of a slitter with respect to a traveling direction of paper web. The slitter slits paper web into two paper web strips. One paper web strip is transported by the paper-threading rope. When a sensor detects a leading end portion of the paper web strip, an affixing device is operated so as to affix the leading end portion of the paper web strip to the paper web leader. Thus, the paper web strip is threaded along the angle-bar paper-threading path.
As shown in
FIG. 18
, which shows the above-described conventional automatic paper-threading device, a gap must be provided between a guide pipe
9
b
and angle bars (first bar
23
and second bar
24
). Thus, the guide pipe
9
b
extends along a route which is more distant from the angle bars than is the actual paper-threading path for a paper web strip
1
c
. As a result, as the paper web strip
1
c
passes the first bar
23
and then the second bar
24
, its slack increases. Also, the paper web strip
1
c
tends to be drawn toward a paper-threading rope
10
b
. Specifically, when the leading end portion of the paper web strip
1
c
passes the first bar
23
, a force acts on the paper web strip
1
c
in the direction of arrow m, since a force of pulling the paper-threading rope
10
b
, or a force directed in the direction of arrow k, is produced at the center of the guide pipe
9
b.
A component force directed in the direction of arrow n of the above-mentioned force directed in the direction of arrow m causes the paper web strip
1
c
to move in the direction of arrow n while traveling in the moving direction of the paper-threading rope
10
b
(in the direction of arrow k). In an initial stage of a paper-threading process, an obliquely cut end portion of the paper web strip
1
c
is in contact with the first bar
23
; in other words, the paper web strip
1
c
is not in contact with the first bar
23
across the entire width thereof. Accordingly, the contact area between the paper web strip
1
c
and the first bar
23
is small, and the paper web strip
1
c
is slack. Thus, a frictional resistance generated between the paper web strip
1
c
and the first bar
23
is low, so that the paper web strip
1
c
easily shifts on the first bar
23
in the direction of arrow q.
Because of the above-described two reasons, when the paper web strip
1
c
is threaded along the angle-bar paper-threading path while being looped around the first bar
23
and the second bar
24
, the paper web strip
1
c
is drawn toward the paper-threading rope
10
b
. In some cases, the thus-drawn side edge of the paper web strip
1
c
may be caught between the paper-threading rope
10
b
and a driving roller
18
a
of a drive unit
18
.
As a result of the obliquely cut leading end portion of the paper web strip
1
c
being drawn toward the paper-threading rope
10
b
, the above-mentioned slack of the end portion emerges in the form of waves in the longitudinal or lateral direction of the paper web strip
1
c
. Upon contact with the first bar
23
and the second bar
24
, these waves become wrinkles, causing a nonuniform tension to act on the end portion, which is narrower than the regular width of the paper web strip
1
c
. As a result, the end portion may be torn.
Since the paper web strip
1
c
must be affixed to the paper web leader of the paper-threading rope
10
b
by means of an affixing device
43
(see
FIG. 17
) at a position located upstream of the first bar
23
, the distance between a side edge of the paper-threading path and the guide pipe
9
b
, through which the paper-threading rope
10
b
travels, is narrower than that at a position located downstream of the second bar
24
. Accordingly, as the paper web strip
1
c
is looped around the first bar
23
and then the second bar
24
, the paper web strip
1
c
deviates increasingly farther from the paper-threading path.
Specifically, as shown in
FIG. 18
, the letter “H” represents the distance between the center of the paper-threading rope
10
b
and a side edge of the paper-threading path for the paper web strip
1
c
as measured in the vicinity of the affixing device
43
; the letter “I” represents that as measured at a position located between the first bar
23
and the second bar
24
; and the letter “J” represents that as measured at a position located downstream of the second bar
24
. The distances H, I, and J exhibit the relationship “H<I<J,” indicating that the distance increases as the paper web strip
1
c
travels forward. The letter “r” denotes the locus of an end portion p of the paper web strip
1
c
along the angle-bar paper-threading path.
The paper web strip
1
c
gradually deviates from the paper-threading path as it is threaded forward while being guided by the paper-threading rope
10
b
. However, the conventional automatic paper-threading device provides no particular measure against this.
SUMMARY OF THE INVENTION
The present invention has been achieved to solve the above problems involved in the conventional automatic paper-threading device, and an object of the invention is to provide an automatic paper-threading device capable of preventing, through employment of a simple mechanism, the occurrence of slack in a paper web strip threaded through an angle bar section to thereby prevent a considerable deviation of the paper web strip from a paper-threading path which would otherwise result from such slack, and thus avoid various problems which would otherwise result from such deviation.
Another object of the present invention is to provide an automatic paper-threading device capable of preventing the occurrence of slack-derived waves on a wave paper strip, to thereby prevent the imposition of a nonuniform tension on the paper web strip and thus prevent tearing of the wave paper strip which would otherwise result from the imposition of a nonuniform tension.
To achieve the above objects, the present invention provides an automatic paper-threading device for use in an angle bar section of a rotary press which includes a paper web supply unit, a press unit, an angle bar section, and a folding unit and which has a paper-threading path for paper web formed between the paper web supply unit and the folding unit. The angle bar section is disposed in the paper-threading path and includes a first bar and a second bar disposed in parallel and separated by an appro
Armstrong Westerman Hattori McLeland & Naughton LLP
Mansen Michael R.
Tokyo Kikai Seisakusho Ltd.
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