Information
-
Patent Grant
-
6189883
-
Patent Number
6,189,883
-
Date Filed
Wednesday, December 16, 199825 years ago
-
Date Issued
Tuesday, February 20, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Capelli; Christopher J.
- Melton; Michael E.
-
CPC
-
US Classifications
Field of Search
US
- 271 94
- 271 96
- 271 98
- 271 97
- 271 99
- 271 108
-
International Classifications
-
Abstract
A sheet feeder for feeding sheets from a sheet stack, having a feed deck for supporting the sheet stack and a pair of spaced apart parallel guide rails on the feed deck for receiving the sheet stack between the guide rails. A sheet feeding assembly is mounted in proximity to a sheet feeding end of the feed deck and is operative to feed individual lowermost sheets from the sheet stack, the sheet feeding assembly including a continuously rotating feed drum having an inner and outer circumference and a plurality of suction openings and a vacuum assembly received in the inner circumference of the feed drum and having at least one rotating cylinder coupled to a vacuum source and movable between an actuated position for drawing air downward through the portion of the feed drum extending above the planar surface of the feed deck and a default position preventing the drawing of air through the feed drum when a vacuum is applied to the at least one rotating cylinder.
Description
FIELD OF THE INVENTION
The present invention relates generally to devices for feeding individual sheets from the bottom of a sheet stack, and more particularly, to a sheet feeder having a pneumatic vacuum assembly for feeding individual sheets from the bottom of a sheet stack.
BACKGROUND OF THE INVENTION
Multi-station document inserting systems generally include a plurality of various stations that are configured for specific applications. Typically, such inserting systems, also known as console inserting machines, are manufactured to perform operations customized for a particular customer. Such machines are known in the art and are generally used by organizations, which produce a large volume of mailings where the content of each mail piece may vary.
For instance, inserter systems are used by organizations such as banks, insurance companies and utility companies for producing a large volume of specific mailings where the contents of each mail item are directed to a particular addressee. Additionally, other organizations, such as direct mailers, use inserts for producing a large volume of generic mailings where the contents of each mail item are substantially identical for each addressee. Examples of such inserter systems are the 8 series and 9 series inserter systems available from Pitney Bowes, Inc. of Stamford, Conn.
In many respects the typical inserter system resembles a manufacturing assembly line. Sheets and other raw materials (other sheets, enclosures, and envelopes) enter the inserter system as inputs. Then, a plurality of different modules or workstations in the inserter system work cooperatively to process the sheets until a finished mailpiece is produced. The exact configuration of each inserter system depends upon the needs of each particular customer or installation.
For example, a typical inserter system includes a plurality of serially arranged stations including a sheet feeding station, a folding station, a plurality of insert feeder stations, an envelope feeder and insertion station and an output station for collecting the assembled mailpieces. As is conventional, the sheet feeder feeds one or a plurality of sheets to an accumulating station, which collects the fed sheets into a predefined collation packet. This collation is then preferably advanced to a folding station for folding the collation. Thereafter, the serially arranged insert feeder stations sequentially feed the necessary documents onto a transport deck at each insert station as the folded collation arrives at the respective station to form a precisely collated stack of documents which is transported to the envelope feeder-insert station where the stack is inserted into the envelope. The finished envelope is then conveyed to an output station for distribution into the mail stream. A typical modem inserter system also includes a control system to synchronize the operation of the overall inserter system to ensure that the mailpieces are properly assembled.
Aside from reliability, one of the most important features of a modem inserter system is speed. Speed is defined as how many mailpieces can be assembled in a given time period. For instance it is known to process up to twelve thousand (12,000) mailpieces each hour, where each mailpiece consists of a three (3) page folded collation and at least one insert. However, speeds much higher than his rate are extremely difficult because current sheet feeders are unable to reliably feed sheets at such high speeds.
Such a known sheet feeder can be found in U.S. Pat. No. 4,579,330 and 4,787,619, both of which are assigned to Mathias Bauerle GmbH of the Federal Republic of Germany. In brief, this is a pneumatic sheet feeder that removes individual sheets from a stack. The sheet feeder includes a table having a surface for supporting a stack of sheets. A pair of parallel guide rails are provided on the table and with facing surfaces so that the stack is confined between the guide rails for movement in a feed direction across the table. Blast nozzles are provided in the guide rails for blowing air against the stack to form an air cushion between lower sheets of the stack. A suction cylinder is rotatably mounted to the table and includes a suction chamber therein for receiving a vacuum. Radial openings in the suction chamber cause a suction induced adhesion of a leading edge of a lowermost feed in the stack so that with rotation of the cylinder, the lowermost sheet is fed in the feed direction away from the rest of the stack.
In use, this sheet feeder has proven reliably when operating at speeds up to approximately 35,000 sheets per hour. The aforementioned sheet feeder is unable to operate at speeds greater than this rate because of its limited speed in the vacuum valve system and in the velocity of its outer feed drum.
Thus, it is an object of the present invention to provide an improved sheet feeder that operates to reliably feed sheets at speeds in excess of that which is capable by the above described prior art sheet feeder.
SUMMARY OF THE INVENTION
Accordingly, the present invention relates to a sheet feeding device having a pneumatic sheet feeding assembly operative to feeds sheets at high speeds and thus overcome the shortcomings of the aforesaid prior art.
Briefly, the present invention relates to a sheet feeder for feeding individual sheets from a sheet stack having a feed deck for supporting the sheet stack and a pair of spaced apart parallel guide rails on the feed deck for receiving the sheet stack between the guide rails. A pneumatic assembly mounted in proximity to a sheet feeding end of the feed deck and is operative to feed individual sheets from the sheet stack.
The pneumatic assembly includes an outer rotatably mounted feed drum having an outer and inner circumference and a plurality of suction openings extending between the inner and outer circumferences wherein at least a portion of the outer circumference extends above a planar surface of the feed deck. An inner vane cylinder having an outer and inner circumference with a vane cutout portion extending between its outer and inner circumference is received within the inner circumference of the feed drum such that the vane cutout portion is in communication with the suction openings of the feed drum extending above the planar surface of the feed deck.
A rotating inner valve cylinder having an outer and inner circumference with a valve cutout portion extending between its outer and inner circumference is rotatably received within the inner vane drum. When the valve cylinder is rotated such that its valve cutout portion is in communication with the vane cutout portion, and a vacuum is applied to the inner circumference of the valve cylinder, air is caused to be suctioned downward through the suction openings of the feed drum so as to cause a sheet on the bottom of the sheet stack to adhere against the rotating feed drum and convey away from the sheet stack.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and advantages of the present invention will become more readily apparent upon consideration of the following detailed description, taken in conjunction with accompanying drawings, in which like reference characters refer to like parts throughout the drawings and in which:
FIG. 1
is a block diagram of a document inserting system in which the present invention is incorporated;
FIG. 2
is a perspective view of the upper portion of the present invention pneumatic sheet feeder;
FIGS. 3
is a perspective exploded view of the pneumatic cylinder assembly of the sheet feeder of
FIG. 2
;
FIG. 4
is a cross-sectional view taken along line
4
—
4
of
FIG. 2
;
FIG. 5
is a cross-sectional view taken along line
5
—
5
of
FIG. 4
;
FIGS. 6 and 6
a
are partial side views of the sheet feeder of
FIG. 2
depicting the mounting block in closed and open positions;
FIGS. 7
is a partial side planar view, in partial cross-section, of the sheet feeder of
FIG. 2
depicting the valve drum in its non-sheet feeding default position;
FIG. 8
is a partial enlarged view of
FIG. 7
;
FIGS. 9-10
are partial enlarged views of
FIG. 7
depicting a sheet feeding through the sheet feeder assembly of
FIG. 2
;
FIGS. 11 and 11
a
are partial enlarged sectional side views of the sheet feeder of
FIG. 2
depicting the vane adjusting feature of the sheet feeder assembly;
FIG. 12
is a sheet flow diagram illustrating the collation spacing provided by the sheet feeder of FIG.
1
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In describing the preferred embodiment of the present invention, reference is made to the drawings, wherein there is seen in
FIG. 1
a schematic of a typical document inserting system, generally designated
10
. A brief description of this typical inserting system
10
is given to set forth the operating environment for the present invention pneumatic sheet feeder, generally designated
100
in
FIGS. 1 and 2
.
In the following description, numerous paper handling stations implemented in a typically prior art inserter system
10
are set forth to provide a brief understanding of a typical inserter system. It is of course apparent to one skilled in the art that the present invention may be practiced without the specific details in regards to each of these paper-handling stations of inserter system
10
.
As will be described in greater detail below, document inserter system
10
preferably includes an input station
100
that feeds paper sheets from a paper web to an accumulating station
11
that accumulates the sheets of paper in collation packets. Preferably, only a single sheet of a collation is coded (the control document), which coded information enables the control system
14
of inserter system
10
to control the processing of documents in the various stations of the mass mailing inserter system. The code can comprise a bar code, UPC code or the like.
Essentially, input station
100
feeds sheets in a paper path, as indicated by arrow “a,” along what is commonly termed the “deck” of inserter system
10
. After sheets are accumulated into collations by an accumulating station
11
, the collations are folded in folding station
16
and the folded collations are then conveyed to a insert feeder station
18
. An example of such an accumulating station
11
can be found in U.S. Pat. No. 5,083,769, which is hereby incorporated by reference. It is to be appreciated that a typical inserter system
10
includes a plurality of insert feeder stations, but for clarity of illustration only a single insert feeder
18
is shown.
Insert feeder station
18
is operational to convey an insert (e.g., an advertisement) from a supply tray to the main deck of inserter system
10
so as to be nested with the aforesaid sheet collation conveying along the main deck. The sheet collation, along with the nested insert(s), are next conveyed to an envelope insertion station
20
that is operative to insert the collation into an open envelope. Afterwards, the stuffed envelope is then preferably conveyed to a transfer module station
22
.
The transfer module
22
changes the direction of motion of flat articles (e.g., envelopes) from a first path (as indicated by arrow “a”) to a second path (as indicated by arrow “b”). In other words, transfer module
22
takes a stuffed envelope from the envelope insertion station
20
and changes its direction of travel by ninety degrees (90°). Hence, transfer module
10
is commonly referred to in the art as a “right-angle transfer module”.
After the envelope changes its travel direction, via transfer module
22
, it is then preferably conveyed to an envelope sealer station
24
for sealing. After the envelope is sealed, it is then preferably conveyed to a postage station
26
having at least one postage meter for affixing appropriate postage to the envelope. Finally, the envelope is preferably conveyed to an output station
28
that collects the envelopes for postal distribution.
As previously mentioned, inserter system
10
also includes a control system
14
preferably coupled to each modular station of inserter system
10
, which control system
14
controls and harmonizes operation of the various modular stations implemented in inserter system
10
. As an example of such a control system can be found in commonly assigned U.S. Pat. Nos. 3,935,429; 4,527,791; 4,568,072; 5,345,547; 5,448,490 and 5,027,279, which are all hereby incorporated by reference in their entirety. Preferably, control system
14
uses an Optical Marking Reader (OMR) for reading the code from each coded document.
It is to be appreciated that the depicted embodiment of a typically prior art inserter system
10
is only to be understood as an exemplary configuration of such an inserter system. It is of course to be understood that such an inserter system may have many other configurations in accordance with a user's specific requirements.
Referring now specifically to the sheet feeder
100
of the present invention, as best shown in
FIG. 2
, sheet feeder
100
includes a base frame having opposing side portions
102
and
104
. A planar deck surface
106
is positioned and supported intermediate the base side portions
102
and
104
. On the deck surface
106
are positioned two sheet guide rails
108
,
110
that extend parallel to each other and are preferably displaceable transversely relative to each other by known means. An open slot
112
is formed on the deck
106
in which a pneumatic cylinder assembly
114
is mounted for rotation within and below a stripper plate
116
extending generally parallel with the cylinder assembly
114
. The pneumatic cylinder assembly
114
includes an outer feed drum
202
that is mounted so that its top outer surface portion is substantially tangential to the top surface of the feed deck
106
and takeaway deck
107
, which takeaway deck
107
is located downstream of the feed drum
202
(as best shown in FIG.
5
). A more detailed description of the pneumatic cylinder assembly
114
and its operation will be provided further below.
With reference to
FIG. 5
, it can be seen that the outer circumference of the feed drum
202
extends between the open slot
112
formed between the angled ends of the two decks
106
and
107
. The respective facing ends of the feed deck
106
and takeaway deck
107
are dimensioned (e.g., angled) so as to accommodate the outer circumference of the feed drum
202
. The top portion of the outer circumference of the feed drum
202
extends above the top surfaces of both decks
106
and
107
, wherein the top surface of the takeaway deck
107
resides in a plane slightly below the plane of the top surface of the feed deck
106
. Preferably the takeaway deck
107
resides in a plane approximately one tenth of an inch (0.100″) below the top planar surface of the feed deck
106
. This difference in deck heights is chosen so as to minimize the angular distance the sheets have to travel around the feed drum
202
when feeding from the feed deck
106
. By reducing this angular distance, the amount of “tail kick” associated with sheets being fed by the feed drum
202
is reduced. “Tail kick” can best be defined as the amount the trail edge of a sheet raises off the feed deck
106
as it leaves the feed drum
202
. It is to be understood that “tail kick” is a function of sheet stiffness and the angle of takeaway as determined by the respective heights of the feed drum
202
and takeaway deck
107
.
The stripper plate
116
is adjustably fixed between two mounting extensions
118
,
120
extending from a mounting block
122
. A first set screw
115
a
is received in a threaded opening in the top of the mounting block
122
for providing vertical adjustment of the stripper blade
116
relative to the deck
106
of the sheet feeder
100
. A second set screw
115
b
is received in a threaded opening in the back of the mounting block
122
for providing lateral adjustment of the stripper blade
116
relative to the feed deck
106
of the sheet feeder
100
.
As will be appreciated further below, the stripper blade
116
allows only one sheet to be fed at a time by creating a feed gap relative to the outer circumference of the feed drum
202
, which feed gap is approximately equal to the thickness of a sheet to be fed from a sheet stack. In particular, the lower geometry of the stripper blade
116
is triangular wherein the lower triangular vertex
117
of the stripper blade
116
is approximately located at the center portion of the sheets disposed on the deck
106
as well as the center of the rotating feed drum
202
. An advantage of the triangular configuration of the lower vertex
117
of the stripper blade
116
is that the linear decrease in the surface area of stripper blade
116
at its lower vertex
117
provides for reduced friction which in turn facilitates the feeding of sheets beneath the lower vertex
117
of the stripper blade
116
. Preferably, it is at this region just beneath the lower vertex
117
of the stripper blade
116
in which resides a metal band
210
positioned around the outer circumference of the feed drum
202
, (and preferably in the center portion of the feed drum
202
) which metal band
210
acts as a reference surface for the position of the lower vertex of the stripper blade
116
to be set in regards to the feed drum
202
. This is particularly advantageous because with the hard surface of the metal band
210
acts as a reference, a constant feed gap between the lower vertex
117
of the stripper blade
116
and the feed drum
202
is maintained.
With continuing reference to
FIG. 3
the center portion of the feed drum
202
is provided with a recessed portion
271
preferably in a triangular configuration dimensioned to accommodate the lower triangular vertex
117
of the stripper blade
116
. Thus, the stripper blade
116
is positioned such that its lower triangular vertex
117
resides slightly above the recessed portion
271
of the feed drum
202
and is preferably separated therefrom at a distance substantially equal to the thickness of a sheet to be fed from a sheet stack residing on the feed deck
106
of the sheet feeder
100
. As can also be seen in
FIG. 2
, the metal band
210
is preferably located in the lower vertex of the of the recessed portion
271
formed in the outer circumference of the feed drum
202
. It is to be appreciated that an advantage of this formation of the recessed portion
271
in the feed drum
202
is advantageous because it facilitates the separation of the lower most sheets (by causing deformation in the center portion of that sheet) from the sheet stack residing on the deck
106
of the sheet feeder
100
.
Also extending from the mounting block
122
are two drive nip arms
134
,
136
each having one end affixed to the mounting block
122
while the other end of each opposing arm
134
,
136
is rotatably connected to a respective “takeaway” nip
138
. Each takeaway nip
138
is preferably biased against the other circumference of the vacuum drum
118
at a position that is preferably downstream of the stripper blade
116
relative to the sheet flow direction as indicted by arrow “a” on the feed deck
106
of FIG.
1
. It is to be appreciated that when sheets are being fed from the feed deck
106
, each individual sheet is firmly held against the rotating feed drum
202
(as will be further discussed below). And when the sheets are removed from the feed drum
106
, as best seen in
FIGS. 8 and 9
, the end portion of the takeaway deck
107
is provided with a plurality of projections or “stripper fingers”
133
that fit closely within corresponding radial grooves
135
formed around the outer circumference of the feed drum
202
so as to remove individual sheets from the vacuum of the feed drum
202
as the sheets are conveyed onto the takeaway deck
107
. That is, when the leading edge of a sheet is caused to adhere downward onto the feed drum
202
(due do an applied vacuum, as discussed further below), the sheet is advanced by the rotation of the feed drum
202
from the feed deck
106
until the leading edge of the sheet rides over the stripper fingers
133
. The stripper fingers
133
then remove (e.g., “peel”) the sheet from the outer vacuum surface of the feed drum
202
. Thereafter, immediately after each sheet passes over the stripper fingers
133
so as to cause that portion of the sheet conveying over the stripper fingers
133
to be removed from the vacuum force effected by outer surface of the feed drum
202
, that portion of the sheet then next enters into the drive nip formed between the takeaway nips
138
and the outer surface of the feed drum
202
, which nip provides drive to the sheet so as to ensure no loss of drive upon the sheets after its vacuum connection to the feed drum is terminated.
Regarding the takeaway nips
138
, and as just stated, they collectively provide positive drive to each sheet that has advanced beyond the stripper fingers
133
. It is noted that when sheets are advanced beyond the stripper fingers
133
, the vacuum of the feed drum
202
is no longer effective for providing drive to those sheets. As such, the takeaway nips
138
are positioned slightly beyond the feed drum
202
and in close proximity to the downstream portion of the stripper fingers
133
as possible. It is noted that due the limited space in the region near the stripper fingers
133
and the takeaway deck
107
, it is thus advantageous for the takeaway nips
138
to have a small profile. Preferably, the takeaway nips
138
are radial bearings having a ⅜″ diameter.
With reference to
FIGS. 1
,
4
and
5
, the mounting block
122
extends from upper and lower mounting shafts
124
and
126
, wherein the lower shaft
126
extends through the mounting block
122
and has it opposing ends affixed respectively in pivoting arm members
128
and
130
. Each pivoting arm member
128
and
130
has a respective end mounted to each side portion
102
and
104
of feeder
100
about a pivoting shaft
142
. The other end of each pivoting arm member
128
and
130
has a respective swing arm
144
,
146
pivotally connected thereto, wherein the pivot point of each swing arm
144
,
146
is about the respective ends of upper shaft
124
, which shaft
124
also extends through the mounting bock
122
. A handle shaft
148
extends between the upper ends of the swing arms
144
and
146
, wherein a handle member
150
is mounted on an intermediate portion of the handle shaft
148
.
In order to facilitate the pivoting movement of the mounting block
122
, and as is best shown if
FIGS. 6 and 6
a
, the lower end portion of each swing arm
144
,
146
is provided with a locking shaft
145
,
147
that slideably extends through a grooved cutout portion (not shown) formed in the lower end portion of each pivoting arm member
128
and
130
, wherein each locking shaft
145
,
146
slideably receives in a grooved latch
151
,
153
provided on each side
102
,
104
of the sheet feeder
100
adjacent each pivoting arm member
128
,
130
. When each locking shaft
145
,
147
is received in each respective grooved latch
151
,
153
, the mounting block
122
is positioned in a closed or locked positioned as shown in
FIGS. 2 and 6
.
Conversely, when the locking shafts
145
,
147
are caused to be pivoted out of their respective grooved latch
151
,
153
(via pivoting movement of the two swing arms
144
,
146
), the mounting block
122
is caused to pivot upward and away from the deck
106
as is shown in
FIG. 6
a
. As also shown in
FIG. 6
a
, when the mounting block
122
is caused to be pivoted to its open position (
FIG. 6
a
), the stripper blade
116
moves along a radial path (as indicated by arrow “z”) so as not to intersect with the sheet stack
400
disposed on the deck
106
of the sheet feeder
100
. This is particularly advantageous because when the mounting block
122
is caused to be moved to its open position (
FIG. 6
a
), the sheet stack disposed on the feed deck need not be interrupted.
Providing an upward biasing force upon preferably one of the pivoting arm members
128
,
130
(and in turn the mounting block
122
) is an elongated spring bar
159
mounted on the outside surface of one of the side portions
104
of the sheet feeder
100
. In particular, one of the ends of the spring bar
159
is affixed to a mounting projection
155
extending from the side
104
of the sheet feeder
100
wherein the other end of the spring bar
159
is caused to upwardly bias against an end portion of a spring shaft
157
extending from one of the swing arms
128
when the mounting block
122
is positioned in its closed position (
FIG. 2
) as mentioned above. The spring shaft
157
extends through a grooved cutout
161
formed in a side portion
104
of the sheet feeder
100
wherein the other end of the spring shaft
157
extends from one of the pivoting arm members
128
. Thus, when the locking shafts
145
,
147
are caused to be pivoted out of their respective grooved latch
151
,
153
(via pivoting movement of the two swing arms
144
,
146
), the upwardly biasing force of the spring bar
159
causes the swing arms
128
to move upward, which in turn causes the mounting block
122
to pivot upward and away from the deck
106
as is shown in
FIG. 6
a
due to the biasing force of the spring bar
159
.
It is to be appreciated that the mounting block
122
pivots upward and away from the deck
106
, and in particular the vacuum drum assembly
114
so as to provide access to the outer surface portion of the outer drum
138
for maintenance and jam access clearance purposes. With continuing reference to FIG.
1
and with reference to
FIGS. 6 and 6
a
, this is effected by having the operator pivot the handle portion
150
, about shaft
124
, towards to deck
106
(in the direction of arrow “b” in
FIG. 6
a
), which in turn causes the pivoting arm members
128
and
130
to pivot upward about respective shafts
142
, which in turn causes corresponding upward pivoting movement of the mounting block
122
away from the deck
106
of the sheet feeder
106
. Corresponding upward pivoting movement is effected on the mounting block
122
by pivoting arm members
128
and
130
due to that shafts
124
and
126
extend through the mounting block
122
, wherein the ends are affixed in respective swing arms
144
and
146
, which are respectively connected to pivoting arm members
128
and
130
.
As shown in
FIG. 5
, downstream of the drive nips
138
is provided an electronic sensor switch
160
in the form of a light barrier having a light source
162
and a photoelectric
164
. The electronic sensor switch
160
is coupled to the inserter control system
14
(
FIG. 1
) and as will be discussed further below detects the presence of sheets being fed from the sheet feeder
100
so as to control its operation thereof in accordance with a “mail runjob” as prescribed in the inserter control system
14
. Also provided downstream of the dive nips
138
is preferably a double detect sensor (not shown) coupled to the control system
14
and being operative to detect for the presence of fed overlapped sheets for indicating an improper feed by the sheet feeder
100
.
With reference to
FIG. 5
, sheet feeder
100
is provided with a positive drive nip assembly
251
located downstream of the takeaway nips
138
and preferably inline with the center axis of the takeaway deck
107
(which corresponds to the center of the feed drum
202
). The drive nip assembly
251
includes an idler roller
253
extending from the bottom portion of the mounting block
122
which provides a normal force against a continuously running drive belt
255
extending from a cutout provided in the takeaway deck
107
. The drive belt
255
wraps around a first pulley
257
rotatably mounted below the takeaway deck
207
and a second pulley
259
mounted within the sheet feeder
100
. The second pulley
259
is provided with a gear that intermeshes with a gear provided on motor
213
for providing drive to the drive belt
255
. Preferably, and as will be further discussed below, motor
213
provides constant drive to the drive belt
213
wherein the drive nip
251
formed between the idler roller
253
and drive belt
255
on the surface of takeaway deck
207
rotates at a speed substantially equal to the rotational speed of the feed drum
202
(due to the feed drums
202
connection to motor
213
). Thus, the drive nip assembly
251
is operational to provide positive drive to a sheet when it is downstream of the takeaway nips
138
at a speed equal, or preferably slightly greater (due to gearing), than the rotational speed of the feed drum
202
.
With returning reference to
FIG. 2
, the side guide rails
108
and
110
are preferably spaced apart from one another at a distance approximately equal to the width of sheets to be fed from the deck
106
of the sheet feeder
100
. Each side guide rail
108
,
110
is provided with a plurality spaced apart air nozzles
166
, each nozzle
166
preferably having their orifice positioned slightly above thin strips
168
extending along rails
108
and
110
on the top surface of the feed deck
106
. The air nozzles
166
are arranged on the inside surfaces of the guide rails
108
and
110
facing each other of rails
108
and
110
, which are provided with valves (not shown) that can be closed completely or partly through manually actuated knobs
37
. It is to be understood that each rail
108
and
110
is connected to an air source (not shown), via hose
101
, is configured to provide blown air to each air nozzle
166
.
Referring now to the pneumatic cylinder assembly
114
, and with reference to
FIGS. 2-5
, the pneumatic cylinder assembly
214
includes the feed drum
202
having opposing end caps
204
,
206
. Each end cap
204
,
206
is preferably threadingly engaged to the end portions of the feed drum
202
wherein the end of one of the end caps
204
is provided with a gear arrangement
208
for providing drive to the feed drum
202
. Preferably the gear
208
of the end cap
204
inter-meshes with a gear
211
associated with an electric motor
213
mounted on the side
104
of the sheet feeder
100
for providing drive to the feed drum
202
. Positioned between the end caps
204
,
206
and the outer surface of the feed drum
202
are metal bands
210
wherein the outer surface of the metal bands
210
are substantially planar with the outer surface, preferably in the recessed portion, of the feed drum
202
, the functionality of which was described above in reference to the setting of the stripper plate
116
relative to the feed drum
202
.
Regarding the feed drum
202
, it is preferably provided with a plurality of radial aligned suction openings
216
arranged in rows. The outer surface of the feed drum
202
is preferably coated with a material suitable for gripping sheets of paper such as mearthane. The outer surface of the feed drum
202
is mounted in manner so as to be spaced from the lower vertex
117
of the stripper plate
116
by a thickness corresponding to the individual thickness of the sheets. Additionally it is to be appreciated, as will be further discussed below, when feeder
100
is in use, the feed drum
202
is continuously rotating in a clockwise direction relative to the stripper blade
116
. Preferably, the feed drum
202
rotates at a speed sufficient to feed at least twenty (20) sheets a second from a sheet stack disposed on the deck
106
of feeder
100
.
Slideably received within the feed drum
202
is a hollowed cylindrical vacuum drum vane
218
. The vacuum drum vane
218
is fixedly mounted relative to the feed drum
202
and is provided with a elongate cutout
220
formed along its longitudinal axis. The drum vane
218
is fixedly mounted such that its elongate cutout
220
faces the suction openings
116
provided on the feed drum
202
preferably at a region below the lower vertex
117
of the stripper blade
116
(
FIG. 5
) so as to draw air downward (as indicated by arrow “c” in
FIGS. 9 and 10
) through the suction openings
216
when a vacuum is applied to the elongate cutout
220
as discussed further below. The vacuum drum vane
218
is adjustably (e.g., rotatable) relative to the outer drum
220
whereby the elongate cutout
220
is positionable relative to the suction openings
216
of the feed drum
202
. To facilitate the aforesaid adjustablity of the drum vane
218
, and with reference also to
FIGS. 11 and 11
a
, an elongate vane adjuster
222
having a circular opening
226
at one of its ends is received about the circular end
224
of the drum vane
218
. A key
228
is formed within the circular end
226
of the elongate vane adjuster, which receives within a corresponding key slot
230
formed in the end
224
of the drum vane
218
so as to prevent movement of the drum vane
218
when the vane adjuster
222
is held stationary. The vane adjuster
222
also is provided with a protrusion
223
extending from its side portion, which protrusion
223
is received within a guide slot
225
formed in a side portion
102
of the sheet feeder
100
for facilitating controlled movement of the vane adjuster
222
so as to adjust the drum vane
218
.
As best shown in
FIGS. 11 and 11
a
, movement of the vane adjuster
222
affects corresponding rotational movement of the drum vane
218
so as to adjust the position of the elongate opening
220
relative to the suction openings
216
of the feed drum
202
. Thus, when the vane adjuster
222
is caused to be moved along the direction of arrow “e” in
FIG. 1
la, the elongate opening
220
of the drum vane
218
rotates a corresponding distance. It is noted that when adjustment of the elongate cutout
220
of the drum vane
218
is not required, the vane adjuster
222
is held stationary in the sheet feeder
100
by any known locking means.
Slideably received within the fixed drum vane
218
is a hollowed valve drum
230
, which is provided with an elongate cutout portion
232
along its outer surface. Valve drum
230
also has an open end
234
. The valve drum
230
is mounted for rotation within the fixed drum vane
218
, which controlled rotation is caused by its connection to an electric motor
214
mounted on a side portion
104
of the sheet feeder
100
. Electric motor
214
is connected to the control system
14
of the inserter system
10
, which control system
14
controls activation of the electric motor
214
in accordance with a “mail run job” as programmed in the control system
14
as will be further discussed below.
The open end
234
of the valve drum
230
is connected to an outside vacuum source (not shown), via vacuum hose
236
, so as to draw air downward through the elongate opening
232
of the valve drum
230
. It is to be appreciated that preferably a constant vacuum is being applied to the valve drum
230
, via vacuum hose
236
, such that when the valve drum
230
is rotated to have its elongate opening
232
in communication with the elongate opening
220
of the fixed drum vane
218
air is caused to be drawn downward through the suction openings
216
of the feed drum
202
and through the elongate openings
220
,
232
of the fixed vane
218
and valve drum
230
(as indicated by arrows “c” in
FIG. 4
) and through the elongate opening
234
of the valve drum
230
(as indicated by arrows “d” in FIG.
4
). As will be explained further below, this downward motion of air through the suction openings
216
facilitates the feeding of a sheet by the rotating feed drum
202
from the bottom of a stack of sheets disposed on the deck
106
of the feeder
100
, which stack of sheets is disposed intermediate the two guide rails
108
,
110
. Of course when the valve drum
230
is caused to rotate such that its elongate cutout portion
232
breaks its communication with the elongate cutout
220
of the fixed vane
218
, no air is caused to move downward through the suction openings
216
eventhough a constant vacuum is being applied to the valve drum
230
.
With the structure of the sheet feeder
100
being discussed above, its method of operation will now be discussed. First, a stack of paper sheets is disposed on the feed deck
106
intermediate the two guide rails
108
,
110
such that the leading edges of the sheets forming the stack apply against the stopping surface of the stripper plate
116
and that the spacing of the two guide rails
108
,
110
from each other is adjusted to a distance corresponding, with a slight tolerance, to the width of the sheets. With compressed air being supplied to the spaced apart air nozzles
166
provided on each guide rail
108
,
110
, thin air cushions are formed between the lowermost sheets of the stack, through which the separation of the sheets from one another is facilitated and ensured.
It is to be assumed that compressed air is constantly being supplied to the air nozzles
166
of the two guide rails
108
,
110
and that the feed drum
202
and drive nip assembly
251
are constantly rotating, via motor
213
, while a constant vacuum force is being applied to the valve drum
230
, via vacuum hose
236
. When in its default position, the valve drum
230
is maintained at a position such that its elongate cutout
232
is not in communication with the elongate cutout
220
of the drum vane
218
which is fixed relative to the constant rotating feed drum
202
. Thus, as shown in
FIGS. 7 and 8
, no air is caused to flow downward through the cutout
220
of the drum vane
218
, and in turn the suction openings
216
of the feed drum
202
eventhough a constant vacuum is applied within the valve drum
230
. Therefore, eventhough the feed drum
202
is constantly rotating and the leading edges of the lowermost sheet of the stack
400
is biased against the feed drum
202
, the feed drum
202
is unable to overcome the frictional forces placed upon the lowermost sheet by the stack
400
so as to advance this lowermost sheet from the stack
400
. Therefore, when the valve drum
230
is positioned in its default position, no sheets are fed from the stack of sheets
400
disposed on the feed deck
106
of the sheet feeder
100
.
With reference to
FIG. 9
, when it is desired to feed individual sheets from the feed deck
106
, the valve drum
230
is rotated, via motor
213
, such that the elongate cutout
232
of the valve drum
230
is in communication with the elongate cutout
220
of the drum vane
218
such that air is instantly caused to be drawn downward through the suction openings
216
on the rotating feed drum
202
and through the respective elongate cutouts
220
,
232
provided on the fixed drum vane
218
and the valve drum
230
. This downward motion of air on the surface of the rotating feed drum
202
, beneath the lower vertex
117
of the stripper plate
116
, creates a suction force which draws downward the leading edge of the lowermost sheet onto the feed drum
202
. This leading edge adheres against the rotating feed drum
202
and is caused to separate and advance from the sheet stack
400
, which leading edge is then caused to enter into the takeaway nips
138
(
FIG. 10
) and then into the positive drive nip assembly
251
such that the individual sheet is conveyed downstream from the sheet feeder
100
. Thus, when the valve drum
230
is rotated to its actuated position (
FIGS. 9 and 10
) the lowermost sheet of the stack
400
is caused to adhere onto the rotating feed drum
202
, convey underneath the lower vertex
117
of the stripper plate
116
, into the takeaway nips
238
and then positive drive nip assembly
251
, and past the sensor
160
, so as to be individual feed from the sheet feeder
100
and preferably into a coupled downstream device, such as an accumulator
11
and/or folder
16
. And as soon as the valve drum
230
is caused to be rotated to its default position (FIGS.
5
and
7
), the feeding of sheets from the stack
400
is immediately ceased until once again the valve drum
230
is caused to be rotated to its actuated position (FIGS.
4
and
9
).
It is to be appreciated that it is preferably the interaction between the sensor switch
160
with the control system
14
the enables the control of the sheet feeder
100
. That is, when motor
214
is caused to be energized so as to rotate the valve drum
230
to its actuated position to facilitate the feeding of sheets, as mentioned above. Since the “mail run job” of the control system
14
knows the sheet collation number of every mailpiece to be processed by the inserter system
10
, it is thus enabled to control the sheet feeder
100
to feed precisely the number of individual sheets for each collation corresponding to each mailpiece to be processed. For example, if each mailpiece is to consist of a two page collation count, the motor
214
is then caused to be energized, via control system
14
, so as to rotate the valve drum to its actuated position (
FIG. 9
) for an amount of time to cause the feeding of two sheets from the sheet feeder
100
, afterwhich the motor
214
is actuated again, via control system
14
, so as to rotate the valve drum
230
to its default position (
FIGS. 7 and 8
) preventing the feeding of sheets. As stated above, the sensor switch
160
detects when sheets are fed from the sheet feeder
100
, which detection is transmitted to the control system
14
to facilitate its control of the sheet feeder
100
.
Of course the sheet collation number for each mailpiece can vary whereby a first mailpiece may consist of a two page collation while a succeeding mailpiece may consist of a four page collation. In such an instance, the control system
14
causes the valve drum
230
to be maintained in its actuated position (
FIG. 9
) for an amount of time to enable the feeding of two sheets immediately afterwards the control system
14
then causes the valve drum
230
to be maintained in its default position (
FIGS. 7 and 8
) for a predefined amount of time. After expiration of this predefined amount, the control system
14
causes to valve drum
230
to be again maintained in its actuated position for an amount of time to enable the feeding of four sheets, afterwhich the above process is repeated with respect to each succeeding sheet collation number for each succeeding mailpiece to be processed in the inserter system
10
.
With reference to
FIG. 12
, it is noted that when the valve drum
230
is caused to be rotated and maintained in its default position (FIGS.
7
and
8
), a predefined space (as indicated by arrow “x”) is caused to be present between the trailing edge
500
of the last sheet
502
of a proceeding collation
504
and the lead edge
506
of the first sheet
508
of a succeeding collation
510
. It is also noted that there is a predefined space (as indicated by arrow “y”) between the trailing and leading edges of the sheets comprising each collation. It is to be appreciated that after the sheets are fed from the sheet feeder
100
, they are then preferably conveyed to a downstream module for processing. An example of which is an accumulating station for accumulating the sheets collation so as to register their edges to enable further processing thereof, such as folding in a folding module
16
. Therefore, the spacing between the trailing edge
500
of the last sheet
502
of a proceeding collation
504
and the lead edge
506
of the first sheet
508
of a succeeding collation
510
(as indicated by arrow “x”) facilitates the operation of downstream module, such as an accumulating module
11
, by providing it with sufficient time to enable the collection and processing of each collation of sheets fed from the sheet feeder
100
in seriatim.
In accordance with the above described preferred embodiment, and in order to preferably feed twenty sheets per second (20 sheets/second) from the sheet feeder
100
, the valve drum
230
operates at a speed approximately equal to 23.26 revolutions/second, whereby a vacuum is then applied to the outside surface of the feed drum
202
, via suction openings
216
, and remains present for a predetermined amount of time sufficient to cause a predetermined amount of sheets to be fed. It is to be appreciated that the control system
14
of inserter system
10
preferably determines the period of time the valve drum
230
is to remain in its actuated position for the feeding of the predetermined number of sheets. For sheets fed in a common collation from the sheet feeder
100
, the valve drum
230
is maintained in its actuated position until the last sheet of a collation is detected, via sensor switch
160
. When this last sheet is detected, the valve drum
230
, as controlled by the motor
214
, will rotate to its default position. As mentioned above, this inter-collation motion profile exists to preferably provide the predefined spaces (e.g., gaps) between the trailing edge of a last sheet of a proceeding collation and the lead edge of a first sheet of a succeeding collation to provide the segregated processing of each respective collation in modules downstream of the sheet feeder
100
(e.g., an accumulator
11
). In particular, the available time between collations (which of course is a function of the aforesaid predefined spaces between collations) is achieved by feeding each sheet of the collation at a period slightly faster than 0.050 second/sheet.
In summary, a sheet feeder having a high-speed pneumatic vacuum assembly for feeding sheets from a stack disposed on a feed deck has been described. Although the present invention has been described with emphasis on particular embodiments, it should be understood that the figures are for illustration of the exemplary embodiment of the invention and should not be taken as limitations or thought to be the only means of carrying out the invention. Further, it is contemplated that many changes and modifications may be made to the invention without departing from the scope and spirit of the invention as disclosed.
Claims
- 1. A pneumatic sheet feeder for feeding individual sheets from a sheet stack, comprising:a feed deck for supporting the sheet stack; a pair of spaced apart parallel guide rails on the feed deck for receiving the sheet stack between the guide rails; and a pneumatic assembly mounted in proximity to a sheet feeding end of the feed deck operative to feed individual sheets from the sheet stack, the pneumatic assembly including: an outer rotatably mounted feed drum having an outer and inner circumference and a plurality of suction openings extending between the inner and outer circumferences wherein at least a portion of the outer circumference extends above a planar surface of the feed deck; an inner vane cylinder having an outer and inner circumference with a vane cutout portion extending between its outer and inner circumference wherein the inner vane cylinder is received within the inner circumference of the feed drum such that the vane cutout portion is in communication with the suction openings extending above the planar surface of the feed deck; and a rotating inner valve cylinder having an outer and inner circumference with a valve cutout portion extending between its outer and inner circumference rotatably received within the inner vane drum, whereby when the valve cylinder is rotated such that its valve cutout portion is in communication with the vane cutout portion, and a vacuum is applied to the inner circumference of the valve cylinder, air is caused to be suctioned downward through the suction openings of the feed drum so as to cause a sheet on the bottom of the paper stack to adhere against the rotating feed drum and convey away from the sheet stack.
- 2. A sheet feeder as recited in claim 1, wherein at least one of the guide rails includes at least one air nozzle for discharging air toward the sheet stack so as to facilitate separation of a lowermost sheet in the sheet stack.
- 3. A sheet feeder as recited in claim 1 further including a sensor located intermediate the feed drum and the sheet feeding end of the sheet feeder for detecting passage of fed sheets from the sheet stack.
- 4. A sheet feeder as recited in claim 1, wherein at least a portion of the outer circumference of the feed drum is coated with Mearthane.
- 5. A sheet feeder as recited in claim 1, wherein the outer feed drum is operatively connected to a first motor operative to provide continuos rotation of the outer feed drum.
- 6. A sheet feeder as recited in claim 5, wherein the inner vane cylinder is rotatably adjustable relative to the outer drum such that the position of the vane cutout portion is adjustably, through rotation of the inner valve cylinder, relative to the suction openings of the feed drum.
- 7. A sheet feeder as recited in claim 6, wherein the inner valve cylinder is operatively connected to a second motor operative to provide rotation of the outer feed drum between a default position wherein the valve cutout portion is not in communication with the vane cutout portion and an actuated position wherein the valve cutout portion is in communication with the vane cutout portion.
- 8. A sheet feeder as recited in claim 7, wherein the inner valve cylinder is coupled to a vacuum source drawing a constant vacuum in the inner circumference of the inner valve cylinder such that when the inner valve cylinder is positioned in the actuated position air is caused to be drawn downward through the suction openings in the rotating outer feed drum.
- 9. A sheet feeder for feeding sheets from a sheet stack having a feed deck for supporting the sheet stack with a pair of spaced apart parallel guide rails on the feed deck for receiving the sheet stack between the guide rails and a sheet feeding assembly mounted in proximity to a sheet feeding end of the feed deck operative to feed lowermost individual sheets from the sheet stack, the sheet feeding assembly including a rotatable feed drum having an inner and outer circumference and a plurality of suction openings extending between the inner and outer circumferences wherein at least a portion of the of the outer circumference extends above a planar surface of the feed deck; the improvement comprising, a vacuum assembly received within the inner circumference of the feed drum and having at least one rotating cylinder coupled to a vacuum source and movable between an actuated position for drawing air downward through the portion of the feed drum extending above the planar surface of the feed deck and a default position preventing the drawing of air through the feed drum when a vacuum is applied to the at least one rotating cylinder.
- 10. A sheet feeder as recited in claim 9, wherein the vacuum assembly includes:an inner vane cylinder having an outer and inner circumference with a vane cutout portion extending between its outer and inner circumference, wherein the inner vane cylinder is received within the inner circumference of the feed drum such that the vane cutout portion is in communication with the suction openings extending above the planar surface of the feed deck; and a rotating inner valve cylinder having an outer and inner circumference with a valve cutout portion extending between its outer and inner circumference rotatably received within the inner circumference of the inner vane cylinder whereby when the valve cylinder is rotated such that its valve cutout portion is in communication with the vane cutout portion, and a vacuum is applied to the inner circumference of the valve cylinder, air is caused to be suctioned downward through the suction openings of the feed drum so as to cause a sheet on the bottom of the paper stack to adhere against the rotating feed drum and convey away from the sheet stack.
- 11. A sheet feeder as recited in claim 9, wherein at least one of the guide rails includes at least one air nozzle for discharging air toward the sheet stack so as to facilitate separation of the lowermost sheet in the sheet stack.
- 12. A sheet feeder as recited in claim 9 further including a sensor located intermediate the feed drum and the sheet feeding end of the sheet feeder for detecting passage of a fed sheet from the sheet stack.
- 13. A sheet feeder as recited in claim 10, wherein the outer feed drum is operatively connected to a first motor operative to provide continuos rotation of the outer feed drum.
- 14. A sheet feeder as recited in claim 13, wherein the inner vane cylinder is rotatably adjustable relative to the feed drum such that the position of the vane cutout portion is adjustably, through rotation of the inner valve cylinder, relative to the suction openings of the feed drum.
- 15. A sheet feeder as recited in claim 14, wherein the inner valve cylinder is operatively connected to a second motor operative to provide rotation of the outer feed drum between a default position wherein the valve cutout portion is not in communication with the vane cutout portion and an actuated position wherein the valve cutout portion is in communication with the vane cutout portion.
- 16. A sheet feeder as recited in claim 15, wherein the inner valve cylinder is coupled to a vacuum source drawing a constant vacuum in the inner circumference of the inner valve cylinder such that when the inner valve cylinder is positioned in the actuated position air is caused to be drawn downward through the suction openings in communication with the vane cutout portion.
US Referenced Citations (8)