Adjustable gripping device for adjustable sheet-receiving pockets and method for adjusting sheet-receiving pockets

Information

  • Patent Grant
  • 6764073
  • Patent Number
    6,764,073
  • Date Filed
    Monday, June 24, 2002
    22 years ago
  • Date Issued
    Tuesday, July 20, 2004
    19 years ago
Abstract
An adjustable gripper system for releasably holding at least one sheet against a surface includes an adjustment body, a gripper connected thereto for holding the sheet against the surface, and a cam follower to be actuated by a cam. The cam follower is connected to the adjustment body and displaces the adjustment body dependent upon a cam position, which correspondingly displaces the gripper along the surface. The system can be part of a sheet-collating pocket having a top portion, forward and rearward walls pivotally connected to one another and defining a sheet-receiving opening, which pocket can be part of a sheet-collating machine having the cam, a conveyor, a sheet feeding device, and other pockets. A method for adjusting the grippers positions the cam in the pocket path to contact each and selectively displace the gripper holding portion with dependent upon the cam position while the cam and pocket contact.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The invention lies in the field of printing presses. The present invention relates generally to a sheet-conveying apparatus, for example, for conveying newspapers, and, more particularly, to a sheet conveying apparatus having collating pockets moving on a track. In particular, the invention relates to an adjustable gripping device for holding folded sheet material sections in such a collating pocket and for separating folded ends of the sections from one another to allow nesting of inserted other sections.




2. Background Information




Sheet-conveying devices, in particular, devices for conveying newspapers, are required to be able to insert or nest or collate various sets of sheets inside one another. Specifically, to create a finished newspaper, a first folded section of the paper, taking the form of a folded sheet section, is opened and at least one second section of the newspaper is inserted between the two sides of the folded sheet section. It is possible that the second section is, itself, a section having third, fourth, or more other sections nested therein in the same manner as the first section. To process such sheets, in particular, newspapers, prior art conveying devices have an angle-shaped pocket that first picks up a first section, opens the first section, and then conveys the opened first section to a delivery station. Prior art systems including pockets include, for example, U.S. Pat. No. 4,133,521 to Müller and U.S. Pat. No. 5,213,318 to Newhall. A delivery unit drops the second section into the opened first section to create a nested paper with two sections. This process can be repeated for many different sections to create an entire newspaper.




There is a difficulty associated with the pocket properly opening the first section to the appropriate opening position. To facilitate proper opening, each section is formed with a lap. In other words, the two ends of the folded sheet section are not even. Typically, in a sheet-processing direction, the forward-most end of the folded sheet section is longer than the rear-most end of the folded sheet section. Thus, if the fold of the sheet section is at the bottom of the pocket, when viewing the ends of the folded sheet section in the pocket from above, the forward lap is higher than the rear lap.




In such a position, the folded sheet section can be opened if the forward, higher lap is secured by a device (applying a physical contact and/or air suction) and the pocket or folded sheet section is moved or tilted to allow gravity (possibly assisted with suction) to let the rear lap fall away from the forward lap. After the rear lap has fallen or is moved away from the forward lap, there exists an opening into which a second section can be inserted. Accordingly, a second section can be inserted into or nested within the first section. This combined section can then be inserted into a further section, and so on, to create a multiply nested set of sheets, typically, forming a common newspaper.




The securing device typically takes the form of a finger-shaped gripper. In the opening process, such a gripper is rotated or lowered onto the forward lap to secure the forward lap, and the forward sheet section, to a front wall of the pocket. Some examples of prior art gripper systems in such pockets include U.S. Pat. No. 4,723,770 to Seidel et al., U.S. Pat. No. 4,988,086 to Schlough, and U.S. Pat. No. 5,024,432 to Thünker et al. However, lap sizes are neither consistent nor equal. Therefore, there is a need to adjust such grippers in a vertical direction with respect to a pocket so that the forward lap is gripped in the most efficient place. Prior art pocket systems solve this positioning problem by vertically adjusting the lowermost surface of the pocket holding the folded sheet section. If such a surface is lowered, the folded section resting thereon is also lowered. Similarly, if the lowermost surface is raised, the folded section resting thereon is also raised. What is needed is more precise lap-gripping adjustment system that is independent of the lowermost surface of the pocket.




U.S. Pat. No. 5,911,416 to Klopfenstein describes a sheet material conveying apparatus with a plurality of pockets moveable around a track to accept sheet material from sheet material feeders. These pockets permit, for example, a first outer section of a newspaper to first be fed into the pockets by a first sheet material feeder, and then an inner newspaper section to be inserted between the folds of the first outer newspaper section. The Klopfenstein apparatus uses a lift cam


20


to move a semicircular actuator gear


150


to rotate a drive shaft


110


so as to set a height for pocket feet


90


disposed on racks


80


. A pawl and ratchet mechanism prevents the pocket from opening. The sheet material can then be accepted and inserted into the pockets. To deliver the sheet material, a trip cam


22


can release the pawl and ratchet mechanism. Tracks


80


move to a lower position through a biasing spring, so that feet


90


release through operation of a driver cam


130


. The sheet material in the pocket can, thus, move out of the pocket from the bottom to be further conveyed or to be stacked. The entirety of Klopfenstein is hereby incorporated by reference.




U.S. Pat. No. 5,251,888 to Eugster purports to describe pockets moveable along an endless path. Each pocket is provided with two vertically adjustable stops


14


mounted displaceably in a pocket carrier


8


. A guide member


28


purportedly can be set to vertically adjust the stops


14


as the pockets are moved along the endless path.




Other examples of adjustment devices for the bottom of a pocket can be found in U.S. Pat. No. 3,891,202 to Kircher, U.S. Pat. No. 4,373,710 to Hansen et al., and U.S. Pat. No. 6,311,968 to Linder et al.




These prior art pocket systems do not provide an adjustment device for setting placement of grippers at the top of the pocket or at the gripper location itself.




SUMMARY OF THE INVENTION




It is accordingly an object of the invention to provide an adjustable gripping device for adjustable sheet-receiving pockets and method for adjusting sheet-receiving pockets that overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that better separates the forward lap from the rearward lap by adjusting grippers in a vertical direction with respect to a pocket so that the forward lap is gripped in the most efficient place.




Commonly assigned U.S. patent application Ser. No. 09/662,277, entitled “SHEET MATERIAL CONVEYING APPARATUS WITH INDIVIDUALLY-ADJUSTABLE POCKETS” filed on Sep. 14, 2000, describes a plurality of manually-adjustable pockets, each having a setting device for adjusting a height of the pocket.




Commonly assigned U.S. patent application Ser. No. 09/702,012, entitled “SHEET MATERIAL CONVEYING APPARATUS WITH HEIGHT-ADJUSTABLE POCKETS” filed on Oct. 30, 2000, describes a plurality of manually adjustable pockets, each having a setting device for adjusting a height of the pocket so as to define a set height.




Commonly assigned U.S. patent application Ser. No. 10/178,651, entitled “ADJUSTABLE GRIPPING DEVICE FOR ADJUSTABLE SHEET RECEIVING POCKETS AND METHOD FOR ADJUSTING SHEET RECEIVING POCKETS” and filed concurrently herewith, describes a different gripper adjusting system


70


having an adjustable gripper


71


with two main parts, a gripper body


72


and an adjustment device


73


including a pivot


75


, a cam follower


77


, and an adjustment body


79


in the form of a two-arm rocker. Depending on a placement setting of a vertically adjustable cam


26


, the adjustment body


79


pivots and moves a nose


74


of gripper body


72


along the surface of upper front wall


52


away from or towards the uppermost edge of the rearward lap


63


.




Commonly assigned U.S. patent application Ser. No. 10/178,642, entitled “LAP SEPARATOR FOR SHEET-RECEIVING POCKETS AND METHOD FOR SEPARATING LAPS IN SHEET-RECEIVING POCKETS” and filed concurrently herewith, describes a lap separator system


70


for extending a window of time for allowing grippers


53


,


55


to engage a forward lap


61


. The lap separating system


70


includes at least one lap separator


72


moveably disposed on a lap separator carrier system


74


, preferably in the form of an endless belt that follows pockets


10


, but moves at a different speed. Lap separator


72


contacts a rearward side of upper rear wall


54


and forces it against upper front wall


52


, thereby clamping a folded section


6


therebetween. As lap separator


72


is traveling with but faster than pocket


10


, it first lets go of upper rear wall


54


, then of rearward lap


63


, and, finally, of upper front wall


52


by dragging over the uppermost edge of each, similar to a fanning of a deck of cards.




A setting device of some of the commonly assigned applications is manually operated by an operator, who turns a knob gear and sets a lock ring for a desired pocket height. It may be desirable to provide a less time consuming, one-step setting device for each pocket.




Each of these commonly assigned applications is hereby incorporated by reference herein.




With the foregoing and other objects in view, there is provided, in accordance with the invention, an adjustable gripper system for releasably holding at least one sheet against a surface, including a rotatable gripper shaft having a shaft axis, at least one gripper connected to the gripper shaft and rotating with the gripper shaft about the shaft axis to selectively hold the sheet against the surface, a pivot shaft having a pivot axis, an adjustment body connected to the pivot shaft for pivoting the adjustment body about the pivot axis, the gripper shaft rotatably connected within the adjustment body, a cam follower to be actuated by a cam, the cam follower connected to the adjustment body for pivoting the adjustment body about the pivot axis, and the adjustment body displacing the gripper shaft about the pivot axis dependent upon a position of the cam to correspondingly displace the gripper along the surface.




In accordance with another feature of the invention, gripper is a plurality of grippers spaced apart from one another on the gripper shaft.




In accordance with a further feature of the invention, the gripper is releasably connected to the gripper shaft. Preferably, the gripper shaft is journaled in the adjustment body.




In accordance with an added feature of the invention, the adjustment body is a lever. Preferably, the lever is a rocker having two ends, a first of the ends is connected to the cam follower, and the gripper shaft is rotatably connected within a second of the ends.




In accordance with an additional feature of the invention, the cam follower is a wheel and an axle rotatably connecting the wheel to the second end.




In accordance with yet another feature of the invention, the gripper shaft is to be connected to a second cam for rotating the gripper shaft about the shaft axis.




With the objects of the invention in view, there is also provided an adjustable gripper system for releasably holding at least one sheet against a surface, including an adjustment body, at least one rotatable gripper rotatably connected to the adjustment body for selectively holding the sheet against the surface, and a cam follower to be actuated by a cam, the cam follower connected to the adjustment body and displacing the adjustment body dependent upon a position of the cam and correspondingly displacing the gripper along the surface.




With the objects of the invention in view, there is also provided a sheet-collating pocket, including a forward wall having an upper end portion, a rearward wall pivotably connected to the forward wall for moving towards and away from the forward wall, the rearward wall and the forward wall together defining an opening for receiving at least one sheet, and an adjustable gripper system for releasably holding the sheet against the forward wall, the gripper system disposed at the upper end portion and having an adjustment body, at least one rotatable gripper rotatably connected to the adjustment body for selectively holding the sheet against the forward wall, and a cam follower to be actuated by a cam, the cam follower connected to the adjustment body and displacing the adjustment body dependent upon a position of the cam and correspondingly displacing the gripper along the forward wall.




In accordance with yet a further feature of the invention, the pocket travels in a given direction, and the forward wall is disposed downstream of the rearward wall with respect to the given direction.




In accordance with yet an added feature of the invention, the upper end portion is an upper third, fourth, or fifth of the forward wall. Preferably, the forward wall has a top and the gripper system is disposed substantially at the top.




With the objects of the invention in view, there is also provided a sheet-collating pocket, including a forward wall having an upper end portion, a rearward wall pivotably connected to the forward wall for moving towards and away from the forward wall, the rearward wall and the forward wall together defining an opening for receiving at least one sheet, and an adjustable gripper system for releasably holding the sheet against the forward wall, the gripper system disposed at the upper end portion and having a rotatable gripper shaft with a shaft axis, at least one gripper connected to the gripper shaft and rotating with the gripper shaft about the shaft axis to selectively hold the sheet against the forward wall, a pivot shaft having a pivot axis, an adjustment body connected to the pivot shaft for pivoting the adjustment body about the pivot axis, the gripper shaft rotatably connected within the adjustment body, a cam follower to be actuated by a cam, the cam follower connected to the adjustment body for pivoting the adjustment body about the pivot axis, and the adjustment body displacing the gripper shaft about the pivot axis dependent upon a position of the cam to correspondingly displace the gripper along the forward wall.




With the objects of the invention in view, in a sheet-collating pocket having a top, a forward wall, and a rearward wall pivotably connected to the forward wall, the rearward and forward walls together defining an opening for receiving at least one sheet from the top, there is also provided an adjustable gripping system for setting placement of grippers at the top of the pocket, the gripping system including an adjustment body, at least one rotatable gripper rotatably connected to the adjustment body for selectively holding the sheet against the forward wall, and a cam follower to be actuated by a cam, the cam follower connected to the adjustment body and displacing the adjustment body dependent upon a position of the cam and correspondingly displacing the gripper along the forward wall.




With the objects of the invention in view, in a sheet-collating pocket having a top, a forward wall, and a rearward wall pivotably connected to the forward wall, the rearward and forward walls together defining an opening for receiving at least one sheet from the top, there is also provided an adjustable gripping system for setting placement of grippers at the top of the pocket, the gripping system including a rotatable gripper shaft having a shaft axis, at least one gripper connected to the gripper shaft and rotating with the gripper shaft about the shaft axis to selectively hold the sheet against the forward wall, a pivot shaft having a pivot axis, an adjustment body connected to the pivot shaft for pivoting the adjustment body about the pivot axis, the gripper shaft rotatably connected within the adjustment body, a cam follower to be actuated by a cam, the cam follower connected to the adjustment body for pivoting the adjustment body about the pivot axis, and the adjustment body displacing the gripper shaft about the pivot axis dependent upon a position of the cam to correspondingly displace the gripper along the forward wall.




With the objects of the invention in view, there is also provided a sheet-collating machine, including a conveyor traveling along a transport direction, at least one sheet feeding device disposed at the conveyor for feeding at least one sheet towards the conveyor, a plurality of sheet-collating pockets, each of the pockets connected to the conveyor, receiving the sheet from the sheet feeding device, and transporting the sheet along at least a portion of the conveyor in the transport direction, an adjustable cam having an adjustment device displacing the cam in different positions with respect to the pockets, the cam disposed at the conveyor and selectively contacting each of the pockets as each pocket respectively passes thereby, and each of the pockets having a forward wall with an upper end portion, a rearward wall pivotably connected to the forward wall, the rearward wall and the forward wall together defining an opening for receiving at least one sheet, and an adjustable gripper system for releasably holding the sheet against the forward wall, the gripper system disposed at the upper end portion and having an adjustment body, at least one rotatable gripper rotatably connected to the adjustment body for selectively holding the sheet against the forward wall, and a cam follower actuated by the cam, the cam follower connected to the adjustment body and displacing the adjustment body dependent upon a position of the cam and correspondingly displacing the gripper along the forward wall.




With the objects of the invention in view, there is also provided a sheet-collating machine, including a conveyor traveling along a transport direction, at least one sheet feeding device disposed at the conveyor for feeding at least one sheet towards the conveyor, a plurality of sheet-collating pockets, each of the pockets connected to the conveyor, receiving the sheet from the sheet feeding device, and transporting the sheet along at least a portion of the conveyor in the transport direction, an adjustable cam having an adjustment device displacing the cam in different positions with respect to the pockets, the cam disposed at the conveyor and selectively contacting each of the pockets as each pocket respectively passes thereby, and each of the pockets having a forward wall with an upper end portion, a rearward wall pivotably connected to the forward wall, the rearward wall and the forward wall together defining an opening for receiving at least one sheet, and an adjustable gripper system for releasably holding the sheet against the forward wall, the gripper system disposed at the upper end portion and having a rotatable gripper shaft having a shaft axis, at least one gripper connected to the gripper shaft and rotating with the gripper shaft about the shaft axis to selectively hold the sheet against the forward wall, a pivot shaft having a pivot axis, an adjustment body connected to the pivot shaft for pivoting the adjustment body about the pivot axis, the gripper shaft rotatably connected within the adjustment body, a cam follower actuated by the cam, the cam follower connected to the adjustment body for pivoting the adjustment body about the pivot axis, and the adjustment body displacing the gripper shaft about the pivot axis dependent upon a position of the cam to correspondingly displace the gripper along the forward wall.




With the objects of the invention in view, there is also provided a method for adjustably gripping at least one sheet within a sheet-receiving pocket of a sheet-collating device, including the steps of conveying sheet-receiving pockets along a transport path, each of the pockets having forward and rearward walls pivotably connected to one another, the forward wall having a top portion, and at least one adjustable gripper having a holding portion for holding at least a portion of a sheet deposited in a respective one of the pockets, the gripper disposed at the top portion, selectively placing a cam into a position in the transport path of the pockets, contacting each of the pockets with the cam to selectively move the holding portion of the gripper dependent upon the selected position of the cam, and while retaining contact between the cam and the pocket opening the forward and rearward walls of each of the pockets to create a sheet-receiving opening, conveying the pockets past a sheet-feeding device, and feeding the sheet into the sheet-receiving opening from the sheet feeding device to place the portion of the sheet against the forward wall, and securely gripping at least the portion of the sheet against the forward wall with the holding portion of the gripper.




With the objects of the invention in view, there is also provided a method for adjusting grippers of sheet-receiving pockets, including the steps of providing sheet-receiving pockets to be conveyed in a transport path, each pocket having a top portion and at least one adjustable gripper having a holding portion for holding at least a portion of a sheet deposited in the pocket, the gripper disposed at the top portion, and positioning an adjustable cam in the transport path of the pockets to contact each of the pockets and selectively displace the holding portion of the gripper dependent upon a set position of the cam such that the portion of the sheet is securely gripped within the pocket with the holding portion of the gripper while contact exists between the cam and the pocket.




In accordance with a concomitant mode of the invention, the gripped sheet is transported in the pocket along at least a portion of the conveyor.




The present invention permits the grippers to be set to a set height while moving and to operate for a relevant distance at the set height. To change a gripper height, a movable setting cam is set for a new height and may also include a lock engagement device. The present invention provides a simple method and device for resetting gripper height and allows for manual re-setting of the gripper height.




“Rod” as defined herein can be any elongated structure. “Slide gear” as defined herein specifically includes any type of slidable interlocking structure, and may include a gear with an exterior star gearing, a single key or tooth exterior structure, or any other structure with which a ring gear may be fixed rotationally and with which a lock ring may be selectively fixed or free to rotate, include one having a ball-detent mechanism.




Other features that are considered as characteristic for the invention are set forth in the appended claims.




Although the invention is illustrated and described herein as embodied in an adjustable gripping device for adjustable sheet-receiving pockets and method for adjusting sheet-receiving pockets, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.




The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a diagrammatic perspective view of a sheet material conveying apparatus according to the invention;





FIG. 2A

is a side view of a pocket according to the invention with certain elements omitted for clarity;





FIG. 2B

is a side view of an enlarged detail of a gripper of the pocket of

FIG. 2A

;





FIG. 3

is a fragmentary perspective view of the pocket of

FIG. 2A

with certain elements omitted for clarity;





FIG. 4

is a different, fragmentary perspective view of the pocket of

FIGS. 3

;





FIG. 5

is a fragmentary, partially exploded, cross-sectional view of a setting device for setting a finger height according to the invention;





FIG. 6

is a fragmentary, exploded, perspective view of the setting device of

FIG. 5

;





FIG. 7

is an enlarged side view of a detail of the setting device of

FIG. 5

;





FIG. 8

is a diagrammatic, fragmentary, cross-sectional view of a gripper system according to the invention;





FIG. 9

is a diagrammatic, fragmentary, cross-sectional view of another position of the gripper system of

FIG. 8

; and





FIG. 10

is a diagrammatic, fragmentary, cross-sectional view of another position of the gripper system of FIG.


8


.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




Referring now to the figures of the drawings in detail and first, particularly to

FIG. 1

thereof, there is shown a diagrammatic representation of a sheet material conveying apparatus


100


having an endless track


101


for transporting a plurality of pockets


10


in transport direction


17


. Each pocket


10


includes moveable fingers


90


for defining a pocket height, an individual height setting mechanism


8


, and a releasable lock mechanism


9


for height setting mechanism


8


.




At a setting area


1


, each pocket


10


can be set manually by setting mechanism


8


to move fingers


90


to at least one of two desired heights, for example, a setting for receiving 10½-inch folded products. Pockets


10


are stationary during setting, and the setting can occur outside setting area


1


as well, for example, by an operator moving about track


101


.




Alternatively, pockets


10


can be moved to setting area


1


, the apparatus can be stopped, and each pocket can be set. An automated robot for interacting with setting mechanism


8


also could be located at setting area


1


to move each pocket


10


to the proper height, as a pocket


10


is moved to and stopped at setting area


1


.




After a pocket is set to a desired height, setting mechanism


8


is then locked in place by lock mechanism


9


so that the pocket height is set. After all pockets


10


are set, they are moved to pass beneath a first sheet material feed station


2


where, for example, a folded cover section


6


of a newspaper or other printed product, also referred to as a jacket, is delivered into pocket


10


. At a second and optional sheet material feed station


3


, a second section


7


may be inserted between forward and rear portions of cover section


6


to form a final printed product


12


. This process can be repeated for any number of feed stations


2


,


3


to create a final product


12


having many nested sections


6


,


7


.




After receiving sections


6


,


7


, pockets


10


can then pass a release station


4


, which releases lock mechanism


9


. Setting mechanism


8


, which is, preferably, spring-loaded, then releases fingers


90


so that the bottom of pocket


10


opens, and finished products


12


are delivered, for example, to a conveyor belt


11


.




As pockets


10


continue past release station


4


, pockets


10


pass through a reset station


5


, which can include a movable incline reset ramp


25


for interacting with a reset cam follower


156


(see

FIG. 3

) of setting mechanism


8


and a lock engagement device


35


for locking lock mechanism


9


. Pockets


10


, which are preferably all set to a common height, are then reset to the common height by reset ramp


25


, and locked into place by lock engagement device


35


engaging lock mechanism


9


.





FIGS. 2A

,


3


, and


4


show more details of pocket


10


.




Pocket


10


has an upper rear wall


54


and an upper front wall


52


, in between which is an opening


56


for accepting sheet material, for example, cover section


6


. Pocket


10


also has a side wall


44


. Pocket


10


also may have a lower rear wall


64


and a lower front wall


62


.





FIG. 2B

is an enlarged view of the upper portion of pocket


10


illustrated in FIG.


2


A.

FIG. 2B

shows the area where a forward lap


61


of a cover section


6


is held. To hold cover section


6


in place, a set of grippers


53


,


55


are located at the top of upper front wall


52


. Grippers


53


,


55


are shown coaxially disposed on a single shaft


57


, albeit in different rotational positions. However, alternatively, different sets of grippers can be disposed on different shafts, each being independently controlled. For example, grippers of one set can be longer than grippers of another set. Also, grippers


53


,


55


are shown at the top of upper front wall


52


. However, grippers


53


,


55


can be located at the upper third, fourth, or fifth of upper front wall


52


, depending upon the distance between the top of section


6


and a top of upper front wall


52


.




A non-illustrated control device pivots shaft


57


holding grippers


53


,


55


between an engaged position and a disengaged position. In

FIG. 2B

, one gripper


53


is shown in the disengaged position and the other gripper


55


is shown in the engaged position. In the engaged position, gripper


55


holds forward lap


61


of cover section


6


so that it is fixed with respect to upper front wall


52


. A cover section


6


being so held is shown diagrammatically in

FIG. 2B

with a dashed line.




When cover section


6


is first deposited in opening


56


, the bottom (lowermost) edge of cover section


6


rests at the junction between fingers


90


and upper rear wall


54


. In the open position of pocket


10


shown in

FIG. 2A

, gravity causes cover section


6


to rest entirely against upper rear wall


54


. To grip cover section


6


with grippers


53


,


55


, upper rear wall


54


is pivoted about axis


51


to contact upper front wall


52


. Alternatively and/or additionally, the entire rear wall


54


,


64


can be displaced towards front wall


52


,


62


. When cover section


6


rests against upper front wall


52


, grippers


53


,


55


can be rotated into the engaged position and hold cover section


6


in place against upper front wall


52


. If grippers


53


,


55


are adjusted so that they extend no further than the top edge of rearward lap


63


of cover section


6


, then grippers


53


,


55


only grip forward lap


61


of cover section


6


. After engaging forward lap


61


, when upper rear wall


54


is moved back to the position shown in

FIG. 2A

, forward lap


61


is held against upper front wall


52


and gravity carries rearward lap


63


of cover section


6


along with upper rear wall


54


, thus creating an opening between forward lap


61


and rearward lap


63


for receiving another section


7


therein, for example, from second sheet material feed station


3


.




Slidable with respect to upper front wall


52


is a rack


80


, on which fingers


90


are supported. Fingers


90


are supported on rack


80


by a pivot


96


attached to a first section


92


of finger


90


. A second section


94


of finger


90


can define a pocket bottom when fingers


90


are in a closed position (as illustrated in FIG.


2


A). As most clearly shown in

FIG. 4

, rack


80


includes teeth


82


that interact with a gear


122


of a pinion


120


(FIGS.


3


and


4


), which also includes a release cam


130


. Pinions


120


are located on a shaft


110


rotatably supported in wall


44


and wall


46


(only partially shown in FIG.


4


).




At wall


46


, an end


111


of shaft


110


passes through a setting ring gear


140


, of which only a first part is shown in FIG.


3


. Ring gear


140


has an interior surface that ensures rotation of ring gear


140


in a fixed relationship with a slide gear


180


(

FIG. 5

) that is in a fixed rotational relationship with shaft


110


. Slide gear


180


, however, can slide axially with respect to shaft


110


for selective interlocking with lock ring


160


(interior to gear


140


and visible in

FIG. 6

) that forms part of lock mechanism


9


. Lock mechanism


9


also includes a pawl


209


for interacting with a single ratchet


164


on the exterior of ring


160


. Ring gear


140


is shown in

FIGS. 2A

,


3


, and


4


only in part, with a second outer gear section


182


(

FIGS. 5 and 6

) for interacting with a non-illustrated setting rod. The details of slide gear


180


and its interaction with ring gear


140


and lock ring


160


will be described in more detail with respect to

FIGS. 5 and 6

.





FIG. 3

shows how fingers


90


extend through the front wall. Release cam


130


can interact with a release surface


100


(

FIG. 4

) of finger


90


located in an opening


86


between teeth


82


when fingers


90


are fully lowered, so that fingers


90


rotate away from rear wall


54


,


64


and release any products in pocket


10


. Release of fingers


90


is similar to the release of the feet in U.S. Pat. No. 5,911,416 to Klopfenstein, which has been incorporated herein by reference.





FIG. 2A

shows ring gear


140


interacting with a semicircular setting gear


150


. On one side of semicircular gear


150


is a reset cam follower


156


held rotationally at an axis


154


. Setting gear


150


pivots about an axis


152


.




As shown in

FIG. 4

, semicircular gear


150


is attached to a spring


158


to spring-load gear


150


in a direction


151


, as also shown in FIG.


2


A.





FIG. 5

shows an exploded view of certain details of the setting mechanism. End


111


of shaft


110


fits, passing through interior holes in ring gear


140


and lock ring


160


, into an interiorly toothed hole


147


of slide gear


180


. End


111


is fixed to a screw


145


that abuts slide gear


180


through a spring


146


. Thus, slide gear


180


can be moved against the force of spring


146


in the direction of arrow


240


so as to slide axially with respect to shaft


110


, however always remaining rotationally fixed with shaft


110


.




Slide gear


180


has exterior star gearing


141


that matches interior star gearing


183


of ring gear


140


. Slide gear


180


and ring gear


140


thus rotate together at all times. Interior to slide gear


180


and ring gear


140


is lock ring


160


, which selectively engages, through an interior star gear


163


, exterior star gearing


141


of slide gear


180


when slide gear


180


is not moved axially against the spring force of spring


146


.




When moved axially against the spring force in direction


240


(see FIG.


5


), slide gear


180


releases from lock ring


160


, which then is held only by pawl


209


but is freely rotatable with respect to shaft


110


due to a smooth inner surface section


162


that rests on shaft


110


.




Slide gear


180


has a raised portion


142


for interacting with a disengaging device of a non-illustrated setting rod to permit slide gear


180


to be moved against the spring force of spring


146


.




Ring gear


140


has external gear teeth


181


for interacting with semicircular gear


150


(FIG.


2


A), as well as external gear teeth of second outer gear section


182


for interacting with the setting rod.




Lock ring


160


has a single ratchet


164


on an external surface, which interacts with pawl


209


, as shown in FIG.


7


. An extension


210


extends outwardly from pawl


209


, for permitting pawl


209


to move between an upward and a downward position. Pawl


209


may be spring-loaded to favor one position, or to click into both positions.




As stated above, after a pocket


10


is set to a desired height, setting mechanism


8


is then locked in place by lock mechanism


9


so that the pocket height is set. After all pockets


10


are set, they are moved to pass beneath at least one sheet material feed station


2


,


3


where, for example, sections


6


,


7


of a newspaper or other printed product are delivered into pocket


10


.




Once pocket


10


is set to a desired height, it typically cannot be adjusted to account for variations in the size of sections


6


,


7


being placed therein. Prior art devices have been created to adjust for such variations by only adjusting the level or location of the bottom of the pocket. Thereby, raising or lowering section


6


,


7


placed therein from below. However, no prior art device has used an adjustment of grippers


53


,


55


to compensate for section


6


,


7


size variation.




As set forth above, up until the invention, there was a difficulty associated with separating forward lap


61


of a first section


6


from rearward lap


63


to create a pocket therebetween into which second section


7


can be inserted or nested.




The invention adds a new adjustment mechanism to grippers


53


,


55


.





FIGS. 8

,


9


, and


10


diagrammatically illustrate a gripper adjusting system


70


. A single adjustable gripper


71


of system


70


is depicted in

FIGS. 8

to


10


for the sake of clarity. Nonetheless, system


70


can be expanded to many or all of the grippers used to grip forward lap


61


in pocket


10


. Single grippers


71


can be independently adjustable. Alternatively, or additionally, one gripper


71


can be adjustable but fixedly connected to one or more other grippers so that the other grippers follow any adjusting movement of the one adjustable gripper


71


. Other equivalent embodiments of grippers are also possible.




Adjustable gripper


71


has two main parts, a gripper body


72


and an adjustment device


73


.




Gripper body


72


has a nose


74


and a fastening portion


76


. Nose


74


directly contacts and holds forward lap


61


of a section


6


, or, if desired, holds the entire section


6


,


61


,


63


. Gripper body


72


is, preferably fixedly but adjustably, attached to gripper shaft


57


(diagrammatically illustrated in

FIGS. 2A and 2B

) through fastening portion


76


. Thus, when shaft


57


rotates about its axis


58


in either rotation direction


59


, gripper body


72


is rotated as well, and nose


74


either lifts away from upper front wall


52


to let go of or make room to grasp forward lap


61


or moves towards upper front wall


52


to grasp forward lap


61


of section


6


. Fastening portion


76


can take any form that connects gripper body


72


to gripper shaft


57


. Preferably, fastening portion


76


releasably clamps to shaft


57


such that, when released, at least to a small extent, fastening portion


76


can rotate around shaft


57


for manual alignment and adjustment.




A preferred embodiment of adjustment device


73


includes a pivot


75


, a cam follower


77


, and an adjustment body


79


in the form of a two-arm rocker, a first rocker arm connecting gripper shaft


57


to pivot


75


, and a second rocker arm connecting pivot


75


to cam follower


77


. Preferably, cam follower


77


is disposed at a distal end of the second rocker arm.





FIGS. 8 and 9

illustrate how adjustment device


73


works.




A vertically adjustable adjustment cam


26


is placed in the path of pockets


10


as they travel in transport direction


17


. Adjustment cam


26


is placed in a position similar to incline reset ramp


25


, in that, a portion of pocket


10


must contact adjustment cam


26


as the portion passes thereby. Adjustment cam


26


can be set to any vertical distance with respect to adjustment device


73


. As a pocket


10


, including gripper adjusting system


70


, approaches and passes adjustment cam


26


, cam follower


77


first contacts ramp


29


and then rolls up and off ramp


29


onto an upper surface


27


of adjustment cam


26


. The movement of cam follower


77


with respect to pivot


75


has a specific affect upon gripper body


72


—the second rocker arm of adjustment body


79


moves up or down dependent upon the position of adjustment cam


26


, thus moving gripper shaft


57


as well. Because shaft


57


is fixedly connected to gripper body


72


, gripper body


72


is likewise moved, causing nose


74


to move along the surface of upper front wall


52


away from or towards the uppermost edge of rearward lap


63


. This movement is dependent upon the placement of adjustment cam


26


.





FIG. 8

illustrates adjustment cam


26


in a raised position with respect to pivot


75


. Accordingly, gripper shaft


57


is in a lowered position with respect to pivot


75


. A lower position of shaft


57


with respect to adjustment cam


26


means that gripper body


72


, and, thus, nose


74


, is relatively close to the uppermost edge of rearward lap


63


at a distance


65


. It is possible, due to a variation in size of rearward lap


63


, that nose


74


actually contacts rearward lap


63


(a condition not illustrated) and prevents rearward lap


63


from falling away from forward lap


61


to create the pocket for receiving an inserted section


7


. Typically, a printing press operator needs to prevent this undesired condition. However, if desired, the invention permits lowering of gripper shaft


57


sufficient to intentionally place nose


74


over rearward lap


63


.




An operator can use the invention and prevent this undesired condition by lowering adjustment cam


26


such that nose


74


no longer contacts rearward lap


63


.

FIG. 9

illustrates adjustment cam


26


in a lowered position with respect to pivot


75


. A higher position of shaft


57


with respect to adjustment cam


26


means that gripper body


72


, and, thus, nose


74


, is relatively far away from the uppermost edge of rearward lap


63


at a distance


67


. In such a position, even if there is a variation in size of rearward lap


63


, nose


74


is sufficiently far away from the uppermost edge of rearward lap


63


to prevent rearward lap


63


from being held by nose


74


.




Therefore, the invention allows an operator to raise a gripper system


70


of each of pocket


10


without having to manually adjust each gripper


71


of each pocket


10


.




Adjustment device


73


need not be a two-arm rocker lever with a pivot


75


. Instead, it can take any form that moves gripper shaft


57


dependent upon an operator-adjustable shaft-setting device


26


such that gripper nose


74


is moved along upper front wall


52


and, therefore, along section


6


to place the end of gripper nose


74


at any position on either or both forward lap


61


and rearward lap


63


.




Similarly, the combination and connection of adjustment body


79


and cam follower


77


can take any form. For example, body


79


can have an axle hole (extending into the plane of the views of

FIGS. 8 and 9

) for receiving an axle or shaft that is then attached to a wheel-shaped cam follower


77


. Other equivalent attachment embodiments can be used as well.




Gripper system


70


shown is a linear raising system. In other words, if adjustment cam


26


is raised by Δh, then gripper body


75


will be pulled into cavity


78


along a distance equal to Δh. Thus, the difference between


65


and


67


is Δh. Gripper system


70


does not have to be a linear raising system, however. It is envisioned to have, if desired, a more complex lever system such that a small raising of adjustment cam


26


results in a correspondingly larger or smaller raising of gripper body


75


.




Ramp


29


of adjustment cam


26


is depicted as being relatively small and shallow. Of course, ramp


29


can have any length or be at any angle greater than 0 degrees and less than 90 degrees. However, preferably, the length of ramp


29


is at least equal to a radius of cam follower


77


. Also preferable is for the ramp angle to be between 30 and 60 degrees, in particular, to be between 30 and 45 degrees. Adjustment cam


26


is shown without a lower surface. Nonetheless, in a preferred embodiment, the forward-most end of ramp


29


is approximately level with such a lower surface and, where cam follower


77


is wheel-shaped, the forward-most portion of adjustment cam is rounded to permit smooth contact between ramp


29


and cam follower


77


.




In the embodiment shown, the bottom of cam follower


77


contacts upper surface


27


of adjustment cam


26


. Alternatively, the top of cam follower


77


can contact a non-illustrated lower surface of adjustment cam


26


. The above-noted example including an axle hole and wheel-shaped cam follower


77


can be used both for contacting upper surface


27


and the lower surface of adjustment cam


27


. But, an embodiment can be made so that cam follower


77


only contacts the lower surface. For example, the second rocker arm can have a non-illustrated groove with a width and cam follower


77


can be a wheel rotatably disposed in such a groove, wheel


77


having a width less than the groove width. Wheel


77


can be attached to the second rocker arm with an axle and cotter pin assembly, for example.




In either embodiment, adjustment body can be attached to a non-illustrated bias device, such as a spring, that biases cam follower


77


in a given rotation direction around pivot


75


.





FIG. 10

illustrates one embodiment for controlling opening and closing of adjustable gripper


71


. Gripper shaft


57


can be connected to a gripper control lever


81


. Preferably, gripper control lever


81


is fixedly, but adjustably, connected to gripper shaft


57


. For example, gripper control lever


81


releasably clamps to shaft


57


such that, when released, at least to a small extent, gripper control lever


81


can rotate around shaft


57


for manual alignment and adjustment. The distal end of gripper control lever


81


includes a second cam follower


83


. Second cam follower


83


can be connected to gripper control lever


81


in any way similar to the connection of cam follower


77


. Further, second cam follower


83


can take any form, including the same form as cam follower


77


. In a preferred embodiment, second cam follower


83


is a roller that is controlled by a second adjustable cam


85


having a cam surface


87


. Second adjustable cam


85


can take any form, including the same form as adjustable cam


26


. In an alternative preferred embodiment, adjustable cam


26


and second adjustable cam


85


are linked to one another in some way so that one is dependent upon another, but with each remaining independently adjustable by an operator.




In operation, when second adjustable cam


85


is at a raised position with respect to gripper shaft


57


, as illustrated in

FIG. 10

, gripper shaft


57


is rotated counter-clockwise to place nose


74


against section


6


, forward lap


61


, and/or rearward lap


63


. Alternatively, when second adjustable cam


85


is at a lowered position with respect to gripper shaft


57


(a condition that is not illustrated), gripper shaft


57


is rotated clockwise to move nose


74


away from section


6


, forward lap


61


, and/or rearward lap


63


.




The invention better separates the forward lap from the rearward lap by adjusting grippers in a vertical direction with respect to a pocket so that the forward lap is gripped in the most efficient place.



Claims
  • 1. An adjustable gripper system for releasably holding at least one sheet against a surface, comprising:a rotatable gripper shaft having a shaft axis; at least one gripper connected to said gripper shaft and rotating with said gripper shaft about said shaft axis to selectively hold the at least one sheet against the surface; a pivot shaft having a pivot axis; an adjustment body connected to said pivot shaft for pivoting said adjustment body about said pivot axis, said gripper shaft rotatably connected within said adjustment body; a cam follower to be actuated by a cam, said cam follower connected to said adjustment body for pivoting said adjustment body about said pivot axis; and said adjustment body adapted to displace said gripper shaft about said pivot axis dependent upon a position of the cam to correspondingly displace said gripper along the surface.
  • 2. The gripper system according to claim 1, wherein said at least one gripper is a plurality of grippers spaced apart from one another on said gripper shaft.
  • 3. The gripper system according to claim 1, wherein said at least one gripper is releasably connected to said gripper shaft.
  • 4. The gripper system according to claim 1, wherein said adjustment body is a lever.
  • 5. The gripper system according to claim 1, wherein:said lever is a rocker having two ends; a first of said ends is connected to said cam follower; and said gripper shaft is rotatably connected within a second of said ends.
  • 6. The gripper system according to claim 1, wherein said gripper shaft is journaled in said adjustment body.
  • 7. The gripper system according to claim 5, wherein said cam follower is a wheel and an axle rotatably connecting said wheel to said second end.
  • 8. The gripper system according to claim 1, wherein said gripper shaft is to be connected to a second cam for rotating said gripper shaft about said shaft axis.
  • 9. A method for adjustably gripping at least one sheet within a sheet-receiving pocket of a sheet-collating device, which comprises:conveying sheet-receiving pockets along a transport path, each of the pockets having: forward and rearward walls pivotally connected to one another, the forward wall having a top portion; and at least one adjustable gripper system according to claim 1, the gripper of the gripper system having a holding portion for holding at least a portion of a sheet deposited in a respective one of the pockets, the gripper disposed at the top portion; selectively placing a cam into a position in the transport path of the pockets; contacting each of the pockets with the cam to selectively move the holding portion of the gripper dependent upon the selected position of the cam; and while retaining contact between the cam and the pocket: opening the forward and rearward walls of each of the pockets to create a sheet-receiving opening; conveying the pockets past a sheet-feeding device; and feeding the sheet into the sheet-receiving opening from the sheet feeding device to place the portion of the sheet against the forward wall; and securely gripping at least the portion of the sheet against the forward wall with the holding portion of the gripper.
  • 10. The method according to claim 9, which further comprises transporting the gripped sheet in the pocket along at least a portion of the conveyor.
  • 11. A method for adjusting grippers of sheet-receiving pockets, which comprises:providing sheet-receiving pockets to be conveyed in a transport path, each pocket having: a top portion; and at least one adjustable gripper system according to claim 1, the gripper of the gripper system having a holding portion for holding at least a portion of a sheet deposited in the pocket, the gripper disposed at the top portion; and positioning an adjustable cam in the transport path of the pockets to contact each of the pockets and selectively displace the holding portion of the gripper dependent upon a set position of the cam such that the portion of the sheet is securely gripped within the pocket with the holding portion of the gripper while contact exists between the cam and the pocket.
  • 12. An adjustable gripper system for releasably holding at least one sheet against a surface, comprising:a rotatable gripper shaft having a shaft axis; an adjustment body adapted to displace said gripper shaft; at least one rotatable gripper for selectively holding the at least one sheet against the surface, said gripper being rotatably connected to said gripper shaft and connected to said adjustment body; and a cam follower to be actuated by a cam, said cam follower connected to said adjustment body and adapted to displace said adjustment body to correspondingly displace said gripper shaft dependent upon a position of the cam and correspondingly displace said gripper along the surface.
  • 13. A sheet-collating pocket, comprising:a forward wall having an upper end portion; a rearward wall pivotally connected to said forward wall for moving towards and away from said forward wall, said rearward wall and said forward wall together defining an opening for receiving at least one sheet; and an adjustable gripper system for releasably holding the at least one sheet against said forward wall, said gripper system disposed at said upper end portion and having: a rotatable gripper shaft having a shaft axis; an adjustment body adapted to displace said gripper shaft; at least one rotatable gripper for selectively holding the at least one sheet against said forward wall, said gripper being rotatably connected to said gripper shaft and connected to said adjustment body; and a cam follower to be actuated by a cam, said cam follower connected to said adjustment body and adapted to displace said adjustment body to correspondingly displace said gripper shaft dependent upon a position of the cam and correspondingly displace said gripper said forward wall.
  • 14. The pocket according to claim 13, wherein:the pocket travels in a given direction; and said forward wall is disposed downstream of said rearward wall with respect to said given direction.
  • 15. The pocket according to claim 13, wherein said upper end portion is an upper third of said forward wall.
  • 16. The pocket according to claim 13, wherein said upper end portion is an upper fourth of said forward wall.
  • 17. The pocket according to claim 13, wherein said upper end portion is an upper fifth of said forward wall.
  • 18. The pocket according to claim 13, wherein said forward wall has a top and said gripper system is disposed substantially at said top.
  • 19. A sheet-collating pocket, comprising:a forward wall having an upper end portion; a rearward wall pivotally connected to said forward wall for moving towards and away from said forward wall, said rearward wall and said forward wall together defining an opening for receiving at least one sheet; and an adjustable gripper system for releasably holding the at least one sheet against said forward wall, said gripper system disposed at said upper end portion and having: a rotatable gripper shaft with a shaft axis; at least one gripper connected to said gripper shaft and rotating with said gripper shaft about said shaft axis to selectively hold the at least one sheet against said forward wall; a pivot shaft having a pivot axis; an adjustment body connected to said pivot shaft for pivoting said adjustment body about said pivot axis, said gripper shaft rotatably connected within said adjustment body; a cam follower to be actuated by a cam, said cam follower connected to said adjustment body for pivoting said adjustment body about said pivot axis; and said adjustment body adapted to displace said gripper shaft about said pivot axis dependent upon a position of the cam to correspondingly displace said gripper along said forward wall.
  • 20. In a sheet-collating pocket having a top, a forward wall, and a rearward wall pivotally connected to said forward wall, the rearward and forward walls together defining an opening for receiving at least one sheet from the top, an adjustable gripping system for setting placement of grippers at the top of the pocket, the gripping system comprising:a rotatable gripper shaft having a shaft axis; an adjustment body adapted to displace said gripper shaft; at least one rotatable gripper for selectively holding the at least one sheet against the forward wall, said gripper being rotatably connected to said gripper shaft and connected to said adjustment body; and a cam follower to be actuated by a cam, said cam follower connected to said adjustment body and adapted to displace said adjustment body to correspondingly displace said gripper shaft dependent upon a position of the cam and correspondingly displace said gripper along the forward wall.
  • 21. In a sheet-collating pocket having a top, a forward wall, and a rearward wall pivotally connected to said, forward wall, the rearward and forward walls together defining an opening for receiving at least one sheet from the top, an adjustable gripping system for setting placement of grippers at the top of the pocket, the gripping system comprising:a rotatable gripper shaft having a shaft axis; at least one gripper connected to said gripper shaft and rotating with said gripper shaft about said shaft axis to selectively hold the at least one sheet against the forward wall; a pivot shaft having a pivot axis; an adjustment body connected to said pivot shaft for pivoting said adjustment body about said pivot axis, said gripper shaft rotatably connected within said adjustment body; a cam follower to be actuated by a cam, said cam follower connected to said adjustment body for pivoting said adjustment body about said, pivot axis; and said adjustment body adapted to displace said gripper shaft about said pivot axis dependent upon a position of the cam to correspondingly displace said gripper along the forward wall.
  • 22. A sheet-collating machine, comprising:a conveyor adapted to travel along a transport direction; at least one sheet feeding device disposed at said conveyor for feeding at least one sheet towards said conveyor; a plurality of sheet-collating pockets, each of said pockets: connected to said conveyor; adapted to receive the at least one sheet from said at least one sheet feeding device; and adapted to transport the at least one sheet along at least a portion of said conveyor in said transport direction; an adjustable cam having an adjustment device adapted to displace said cam in different positions with respect to said pockets, said cam disposed at said conveyor and adapted to selectively contact each of said pockets as each pocket respectively passes thereby; and each of said pockets having: a forward wall with an upper end portion; a rearward wall pivotally connected to said forward wall, said rearward wall and said forward wall together defining an opening for receiving at least one sheet; and an adjustable gripper system for releasably holding the at least one sheet against said forward wall, said gripper system disposed at said upper end portion and having: a rotatable gripper shaft having a shaft axis; an adjustment body adapted to displace said gripper shaft; at least one rotatable gripper for selectively holding the at least one sheet against said forward wall, said gripper being rotatably connected to said gripper shaft and connected to said adjustment body; and a cam follower actuated by said cam, said cam follower connected to said adjustment body and adapted to displace said adjustment body to correspondingly displace said gripper shaft dependent upon a position of said cam and correspondingly displace said gripper along said forward wall.
  • 23. A sheet-collating machine, comprising:a conveyor adapted to travel along a transport direction; at least one sheet feeding device disposed at said conveyor for feeding at least one sheet towards said conveyor; a plurality of sheet-collating pockets, each of said pockets: connected to said conveyor; adapted to receive the at least one sheet from said at least one sheet feeding device; and adapted to transport the at least one sheet along at least a portion of said conveyor in said transport direction; an adjustable cam having an adjustment device adapted to displace said cam in different positions with respect to said pockets, said cam disposed at said conveyor and adapted to selectively contact each of said pockets as each pocket respectively passes thereby; and each of said pockets having: a forward wall with an upper end portion; a rearward wall pivotally connected to said forward wall, said rearward wall and said forward wall together defining an opening for receiving at least one sheet; and an adjustable gripper system for releasably holding the at least one sheet against said forward wall, said gripper system disposed at said upper end portion and having: a rotatable gripper shaft having a shaft axis; at least one gripper connected to said gripper shaft and rotating with said gripper shaft about said shaft axis to selectively hold the at least one sheet against said forward wall; a pivot shaft having a pivot axis; an adjustment body connected to said pivot shaft for pivoting said adjustment body about said pivot axis, said gripper shaft rotatably connected within said adjustment body; a cam follower actuated by said cam, said cam follower connected to said adjustment body for pivoting said adjustment body about said pivot axis; and said adjustment body adapted to displace said gripper shaft about said pivot axis dependent upon a position of said cam to correspondingly displace said gripper along said forward wall.
US Referenced Citations (7)
Number Name Date Kind
4046367 Merker et al. Sep 1977 A
4723770 Seidel et al. Feb 1988 A
4988086 Schlough Jan 1991 A
5024432 Thünker et al. Jun 1991 A
5112036 Hatt May 1992 A
5911416 Klopfenstein Jun 1999 A
6311968 Linder et al. Nov 2001 B1