US3392973A

US3392973A - Warped sheet feeding mechanism

Info

Publication number: US3392973A
Application number: US520219A
Authority: US
Inventors: William F Ward; William F Thoms; William C Staley
Original assignee: WARD DIE VISE CO
Current assignee: WARD DIE VISE CO
Priority date: 1966-01-12
Filing date: 1966-01-12
Publication date: 1968-07-16
Anticipated expiration: 1985-07-16
Also published as: GB1094289A

Description

July 16, 1968 w. F. WARD ETAL WARPED SHEET FEEDING MECHANISM 4 Sheets-Shem 1 Filed Jan. 12, 1966 A M A m m",

INVENTORS WILL MM F THOMS W/LL/AM 6'. .STALEY ATTORNEY BY Mam July 16, 1968 w. F. WARD ETAL 3,392,973

WARPED SHEET FEEDING MECHANISM Filed Jan. 12, 1966 4 Sheets-Sheet 2 INVENTORS W/LL/AM E WARD WILL/14M THOMS W/LL/AM C. 57211.5)

ATTORNEY W. F. WARD ETAL WARPED SHEET FEEDING MECHANISM July 16,1968

F iled Jan. 12, 1966 4 Sheets-Sheet 5 INVENTORS F WARD WILL IA F. 77%? ATTORNEY July 16, 1968 w. F. WARD ET AL 3,392,973

WARPED SHEET FEEDING MECHANISM Filed Jan. 12, 1966 4 Sheets-Sheet 4 INVENTORS W/LL/AM 5 1464190 WILLIAM F THO/W5 WILL/AM C STALL Y ATTORNEY United States Patent 3,392,973 WARPED SHEET FEEDING MECHANISM William F. Ward, Hampstead, William F. Thoms, Baltimore, and William C. Staley, Towsou, Md., assignors to The Ward Die-Vise Company, Baltimore, Md., a corporation of Maryland Filed Jan. 12, 1966, Ser. No. 520,219 8 Claims. (Cl. 271-44) ABSTRACT OF THE DISCLOSURE A mechanism for bottom feeding stiff sheets from a pile is provided wherein pressure on the top of the pile for straightening the sheets is not required, whereby more sheets can be added to the pile, the mechanism comprising structure including a threshold defining a feed opening along the bottom sheet of one side of the pile, shoes for positioning the bottom sheet along the opposite side of the pile, fingers entering the named sides of the pile and urging the bottom sheet against the threshold and the shoes, and a reciprocating bar for pushing the bottom sheet through the opening.

This invention relates generally to sheet feeding apparatus, and more particularly it pertains to a mechanism for forming a pack of sheets for bottom delivery.

Old machines which feed stiff corrugated board, cardboard, or fibreb-oard encountered trouble with warped sheets. A constant hold-down was required on top of the pack to flatten it so only the bottom sheet would be engaged and pass under a feed gate. One approach to the problem utilized a spring pusher pawl and buckling of the pack. The replenishment of the pack required the removal of the pack hold-down each time and unless the machine was stopped a jam often resulted. The spring pusher pawl, too, was troublesome because its height prevented a straight-in feed from the bed of the machine.

It is an object of this invention to overcome the stated problems by providing a novel hold-down mechanism which operates by fingers entering the edge of the pack, and utilizing a pneumatic cylinder which re-cocks when the finger approaches the bottom.

Another object of this invention is to provide means synchronous with the pusher pawl so the pneumatic cylinder pressure is never released while a sheet is in a pushing cycle.

Yet another object of this invention is to provide near pressure mechanism for the pack utilizing edge entering fingers which renew their grip after each stroke of the pusher.

Still another object is to provide a marked sheet feeder mechanism having unobstructed pack loading and a low silhouette straight-in pusher pawl requiring no spring for bottom sheet engagement.

Other objects and attendant advantages of this invention will become more readily apparent and understood from the following detailed specification and accompanying drawings in which:

FIG. 1 is a side elevation, somewhat diagrammatic, of a rotary die cutting and creasing machine using the improved warped sheet feeder apparatus;

FIG. 2 is an enlarged top plan view of the feed area of the machine of FIG. 1 with the pack removed and feed bar 16 displaced from beneath the feeder assembly for clarity;

FIG. 3 is an enlarged top view of a shaft actuator assembly;

FIG. 4 is the side elevation of a shaft actuator assembly shown with the cam of the feed bar thereunder;

FIG. 5 is a side elevation of the rear pawl assembly;

3,392,973 Patented July 16, 1968 FIG. 6 is a plan sectional view of the rear pawl assembly taken on the line 66 of FIG. 5;

FIG. 7 is a side elevation of the front hold down and gate assembly; and

FIG. 8 is a front elevation of the front hold down and gate assembly.

Referring now to the details of the drawings as shown in FIGS. 1 and 2, reference numeral 10 indicates generaly a rotary cutting and creasing machine. This machine 10 may also be of any other type such as a printing machine, folder, stuffer or the like requiring the feeding of sheets. A rear table or table arms 12 extends from the machine 10 at the input end and supports a fixed feeder assembly 14 in an adjustable position, and a reciprocating feed bar 16 which sweeps under the latter and to the rear.

A sweep arm 18 on the machine 10 and linkage 20 stroke the feed bar 16 back and forth on the table arms 12. A pair of right angled pack alignment cheeks 22 are secured forward above the table arms 16 to a cross member 24 of the machine 10.

This cross member 24 also carries a pair of front hold down and gate assemblies 26. Between the pair of cheeks 22 at the sides and between the front hold down and gate assembly 26 and fixed feeder assembly 14 at the rear there is a pack area 28 in which a pack P of sheets S may be loaded.

The reciprocating feed bar 16 carries a ramp-like cam 30 near one end and also, intermediate the ends, a plurality of thin pusher pawls 32 each less than the thickness of a sheet S in height.

The fixed feeder assembly 14 has a plurality of rear pawl assemblies 34 each having a pecking finger 36 and strung on a pair of

shafts

38 and 40. One shaft 38 is merely a support rod, while the other shaft 40 supports as well as actuates the rear pawl assemblies 34 through oscillation. The oscillation is imparted to shaft 40 by means of a shaft actuator assembly 42 mounted at either end of the fixed feeder assembly 14. This motion occurs each time the cam 30 is stroked under the shaft actuator 42. Also shown in FIGS. 1 and 2 are pack alignment springs 44 which serve to urge the pack P forwardly as it is stacked in front of the feeder assembly 14.

The shaft actuator assembly 42 is shown in detail in FIGS. 3 and 4 and consists of a cam follower 46 mounted on the end of a bar 48 which is attached to the shaft 40 through a pair of overtravel absorbing springs 50. Each pass of the cam 30 causes the bar 48 to tilt and the shaft 40 to oscillate.

As shown in FIGS. 5 and -6, the shaft 40 moves other bars 52, and isolating or bias springs 54, in turn, tend to move a pecking arm 56 pivoted on shaft 40 in each pawl assembly 34 from the dotted position to a downward position shown in solid lines. Actually, a sharpened point 58 on the end of the pecking finger 36 enters the edge of the pack P at some intermediate point and moves down as far as the bias springs 54 allow. The pecking finger 36 is biased by a compression coiled spring 60 so as normally to extend radially outward somewhat with relation to arm 56. A shoe 62 secured to each pawl assembly 34 positions the lowermost sheet S of the pack P in proper relation to the in-moving pusher panel 32 of the feed bar 16 previously described.

The front hold down and gate assembly 26 consists of a pair of vertical slide members 64 which are provided with gear racks 66 and geared together with a pair of intermediate gears 68 for simultaneous upward or downward movement. A sharp pawl finger 70 is mounted on the lower end of each slide member 64. In the same vertical plane with the slide members 64, a gate member 72 is provided which extends downwardly nearly to a thin threshold plate 74 leaving a gap for a single sheet S from the pack P to pass.

The pawl fingers 70 are urged from the elevated position shown to a lower position (in phantom lines, FIG. 7) by a pneumatic cylinder 76 which connects with one of the slide members 64. An upper limit switch 78 and a lower limit switch 80 are also actuated by the pneumatic cylinder 76.

An electrically operated valve 82 as shown in FIG. 1 controls the introduction of air pressure to pneumatic cylinder 76 and, in turn, the

limit switches

78 and 80 control the valve 82. A synchronizing switch 84 is positioned adjacent to the sweep arm 18 of the machine 10, and it opens the electric circuit between the lower limit switch 80 and the valve 82 whenever a stroke cycle is occurring. In this manner, a low limit command for the pneumatic cylinder 76 to recock or go to the top is never allowed to occur and release pressure on the pack P at such time.

It will be noted that the pawl fingers 70 enters the edge of pack P near the top thereof each time the pneumatic cylinder 76 restrokes upward. In their downward movement under urging by the cylinder 76, pressure is exerted by the fingers on the pack P in a constant bias.

The rear pawl assemblies 34 however peck or renew the engagement of their pecking fingers 36 with the pack P with each feed stroke of the feed bar 16.

At all times, the pack area 28 is open and accessible for replenishment of the pack P. Any warped sheets S are pressed down and flattened both against threshold plate 74 and shoe '62 permitting perfect feeding of the sheets S one at a time without a miss-stroke.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Mechanism for feeding stiff sheets from the bottom of a pack thereof, comprising, structure including a threshold member and gate means spaced therefrom to form an opening along one side of said pack for the passage of the bottom sheet of said pack, reciprocating means positioned along the opposite side of said pack for pushing said bottom sheet through said opening, shoe means for positioning said bottom sheet for said pushing by said reciprocating means, and finger means for entering said one side and said opposite side of said pack and urging said bottom sheet against said threshold member and said shoe means, whereby said bottom sheet is flattened to facilitate pushing by said reciprocating means and yet the top of said pack remains open for the addition of more of said stiff sheets to said pack.

2. The mechanism of claim 1, and fluid pressure cylinder means having a piston operatively connected to said finger means along said one side of said pack, with said piston maintaining the entrance engagement of said last-mentioned finger means with said pack during the successive feeding of a plurality of said stiff sheets from the bottom thereof.

3. The mechanism of claim 2 and control means for shifting said piston and thereby said engagement of said finger with said one side of said pack to a higher portion thereof.

4. The mechanism of claim 3 and additional control means for preventing said shifting during the pushing of said bottom sheet by said reciprocating means.

#5. The mechanism of claim 4 and means for oscillating the finger means along said opposite side of said pack into and out of engagement therewith in response to said pushing by said reciprocating means.

6. The mechanism of claim 1 and means for oscillating the finger means along said opposite side of said pack into and out of entrance engagement therewith in response to said pushing by said reciprocating means.

7. The mechanism of claim 1 wherein said spring means biases said finger means along said opposite side of said pack into entering said pack.

8. The mechanism of claim 1 wherein said finger means along said opposite side of said pack are pivotally mounted and cam means are mounted on said reciprocating means for pivoting said finger means out of entrance engagement with said pack during said pushing by said reciprocating means.

References Cited UNITED STATES PATENTS 1,490,773 4/1924 Gunn 271-44 EDWARD A. SROKA, Primary Examiner.