US3425685A - Paper feed mechanism - Google Patents

Description

Feb. 4, 1969 I R. H. LIVA I 3,425,535

PAPER FEED MECHANISM 1 Filed Dec. 27. 1966 MOTOR r CONTROL Q E Q /4 m /4 FIG. 2 FIG. 3

Q 2o V T9 \v' 3 x f CONTROL 29 r v 1 4 INVENTOR. 25 ROBERT H. LIVA MOTOR A TTORNEYS United States Patent 1 Claim ABSTRACT OF THE DISCLOSURE A paper feeding apparatus adapted for top or bottom feeding of sheets from a stack. A restraining roller is applied to the stack and resists movement of each top sheet in one direction, rearwardly. A feed roller rotatable in a direction to move each sheet rearwardly is periodically placed in engagement with the forward edge of each sheet, transverse thereto to produce a bend in the sheet by pulling the forward end thereof rearwardly against the holding force effective on the sheet. The forward edge is pulled around the feed roller and moved upwardly thereby to the nip between the feed roller and a second one associated therewith. Both feed rollers are moved reciprocally in union relative to the stack to accomplish periodic engagement of the first feed roller and the stack.

This invention relates to paper handling devices and, in particular, to a sheet paper feeding mechanism that is adapted to feed sheets seriatirn either from the top of a stack of paper or from the [bottom of the stack.

Generally, sheet separating and feeding apparatus which are capable of high speed are relatively complicated, requiring a complexity of moving linkages or suction cups that limit the orientation of a paper stack in a using machine to which the separating and feeding apparatus is applied. The operation of these apparatus usually are restricted to the top plane of a paper stack and, therefore, are limited to top loading use. In any event, the complexity and intricate design specification of these apparatus limits the adaptability or flexibility of these apparatus as bottom or side feeders as well as a top feeder apparatus.

Therefore, it is an object of the invention to improve separating and feeding apparatus whereby these functions can be accomplished either in relation to the top of a paper stack or from the bottom of the stack in order to permit the adding of sheet material to the stack While the paper feeding apparatus remains in operation.

It is another object of the invention to separate and feed sheet material from a stack utilizing operating mechanisms which do not extend or have any portions thereof extend beyond the leading edge of the stack there-by permitting the close, unobstructed application of the mechanisms to the next working stage.

Another object of the invention is to improve paper feeding operation by arranging feed means which are capable of variable control from Zero output to operations up to the speed of 200 sheets per minute or more.

The separating and feeding apparatus according to one embodiment of the present invention comprises a sheet engaging roller disposed above a stack of sheet material and being arranged to hold or restrain movement of the topmost sheet to the rear as its forward edge is moved rearwardly from the front edge of the stack or that edge which is immediately adjacent the next sheet handling device such as a paper conveyor or directly into a duplicator or reproduction apparatus to which the sheet feeding mechanism of the present invention is adapated to be combined. The sheet engaging or restraining roller is adapted to cooperate with one feed roller of a pair of 3,425,685 Patented Feb. 4, 1969 feed rollers for producing a bend in the top sheet in order to carry the leading edge of the top sheet along with the periphery of the feed roller of the pair, which action carries the leading edge of the sheet into the nip of the two feed rollers.

When the leading edge of the top sheet reaches the nip, the two feed rollers will then drive the sheet off the top of the stack. The pair of feed rollers are arranged to move in unison in a reciprocatory motion toward and away from the top plane of the stack and normal thereto. The feed rollers are adapted to rotate in opposite directions and preferably one is made to drive the other. As the lower roller of the pair contacts the top sheet, it drives the leading edge thereof toward the rear of the stack and with the top sheet being restrained against movement to the rear by the restraining roller, a fold or bend in the top sheet is formed between the restraining roller and the lower feed roller. This action will cause the leading edge of the top sheet to be grasped by the high frictional material of the bottom feed roller and to be carried to the nip between the feed rollers as aforesaid.

Another embodiment of the invention results in the separation and feeding of the bottommost sheets of a stack of sheet material. In this arrangement the stack is supported by a forwardmost support roller and half-tray bottom plate or a plurality of rollers. The restraining roller and the feed rollers perform the same action as the previously described embodiment for producing a bend in the lowermost sheet and to carry the forward edge thereof to the nip of the two feed rollers whereupon the sheet is pulled in a positive manner by the two feed rollers.

Further objects of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, wherein:

FIGURE 1 is a schematic view of a sheet separating and feeding mechanism in accordance with the present invention;

FIGURE 2 is a schematic illustration showing a feed separating roller and the feed rollers in one stage of operation;

FIGURE 3 is a schematic illustration similar to FIG- URE 2 showing the feed mechanism is still another stage of operation; and

FIGURE 4 is a schematic illustration of another embodiment of paper separating and feed mechanism in accordance with the present invention arranged to feed the Ibottommost of a stack of sheet material.

Referring now to FIGURES l, 2, and 3 for one embodiment of the invention, there is shown a stack 10 of sheet material arranged for a paper handling function in a paper tray indicated by reference 11. The paper tray 11 may be combined with a suitable paper level control in order to maintain the top of stack 10 at a predetermined height or, at least to within the thicknesses of a few sheets of paper.

Placed in contact with the topmost sheet of the stack is a restraining roller 12 supported on a shaft by any suitable means for maintaining the roller at the predetermined height such that the periphery of the roller remains continuously in contact with the topmost sheet. The roller is mounted freely for rotation in one direction and may be rotated when the topmost sheet is pulled out in a forward direction and, is held against rotation in the opposite direction or that direction which a force may tend to drive the top sheet toward the rear of the stack. In order to accomplish this, the shaft supporting the roller 12 may be provided with a one Way clutch to permit uni-directional rotation of the roller.

At the forward end of the stack or that end from which the sheets are to be fed, there is positioned above the stack a pair of feed rollers 14 and 15 journaled for rotation in a frame 16 which is mounted for reciprocable movement in a vertical plane or in directions normal to the plane of the topmost sheet of the stack. This movement of the rollers 14 and 15 is accomplished by a solenoid 17 mechanically coupled to the frame 16. The vertical reciprocable movement of the frame 16 and, consequently, the rollers 14 and 15 is very slight, a matter of a few thicknesses of paper and may be produced by the solenoid 17 in one direction and a suitable spring or by gravity in the other direction. A control device 18 is connected to the solenoid 17 for controlling periodic energization thereof and therefore the vertical movements of the frame 16. It is to be realized also that other modifications such as the use of rotary cams instead of a solenoid for effecting periodic movement of the feed roller frames will readily occur to those skilled in the art and such modifications are intended to be included herewith.

The peripheries of the lower feed roller 14 and the upper roller 15 are made of relatively high-friction material, such as soft rubber composition and are held in driving cooperation by the frame 16. A motor is mechanically coupled to the feed rollers in order to produce rotation thereof thereby producing clockwise rotation of the lower feed roller 14, which serves as a separating roller for the first stage of its operation and, counterclockwise rotation of the upper feed roller 16. In operation, the motor 19 remains continuously energized in order to produce continuous rotation of the feed rollers 14 and 15. The control device 18 may be a timing circuit for producing periodic energization of the solenoid 17 in order to produce corresponding reciprocal movement of the feed rollers in a vertical direction whereby at its lower point of movement the lower roller 14 is in light pressure contact with the topmost sheet of the stack and at its uppermost point of travel the lower feed roller 14 rises a few paper thicknesses above the topmost sheet in order to be out of contact with the next top sheet when the one being acted upon has been pulled from below the roller.

In a feeding operation, with the lower and upper feed rollers 14 and 15 in continuous motion and the frame 16 has been lowered, when the lower roller engages the topmost sheet S, the combined action of the roller 12 and the feed roller 14 produces a fold or bend in the topmost sheet since the rotation of the roller tends to drive the sheet rearwardly and this movement is resisted by the restraining action of the roller 12. The bending then is caused in part by the forward edge of the sheet S being slid back or to the rear upon the second sheet of the stack. The bend or fold produced in the topmost sheet has the effect of producing a slight spring force upon the leading edge thereof and with the leading edge pulled back from the point where the sheet was tangent to the lower roller results in the leading edge adhering to the high frictional material comprising the periphery of the roller 14.

Simultaneously with this action the frame 16 is moved upwardly by the solenoid 17 to raise the lower roller 14 away from the stack in order to prevent this roller from coming in contact with the next sheet of the stack prematurely before the sheet S 'is able to be separated from the stack. As shown in FIGURE 2, the forward edge E of the sheet S is carried upwardly by the continual rotation of the roller 14 toward the nip of the two rollers 14 and 15. When the leading edge is in the nip, it is diven positively by the two feed rollers with a relatively great force, more or less, a snap-action movement, in order to accomplish relatively fast movement of the sheet at this point. In FIGURE 3, the sheet S is shown being fed by the rollers 14 and 15 in order to present the sheet to the next stage of paper handling which, for example, may be a paper transport mechanism or the rotary drum of a duplicating or reproduction machine. As

previously stated, the shaft carrying the roller 12 includes a one-way clutch so that the pull upon the sheet S by the rollers 14 and 15 will produce rotation of the roller 12 and thereby eliminate the possibility of a retarding force being effective upon a sheet being fed.

In the second embodiment of the invention, as shown in FIGURE 4, the paper stack 10 is shown in a paper tray 20 comprising a bottom half shelf 21 adapted to support, more or less, the rear half of the stack area and a forward wall 22 to prevent inadvertent slippage of the papers in the stack in a forward direction. Any other suitable paper tray arrangement may be utilized, such as a plurality of rollers instead of the shelf 21, which will permit an open exposure of the lower portions of the paper stack. At the forward end of the stack 10 and holding this end of the stack upwardly is a support roller 23 suitably journaled in the machine frame that utilizes the paper feeding mechanism.

Separation and feeding of the lowermost sheet S is effected by a restraining roller 24 mounted for rotation below the stack 10 and an upper feed roller 26 engageable with the forward end of the stack of sheets. The roller 24 cooperates with the upper feed roller 26 in the same way that the feed roller 14 cooperates with the roller 12 and, is mounted for rotation in a frame 27 which also carries a lower feeding roller 28 journaled therein.

As shown in FIGURE 4, the top feeder roller 26 is driven in a counterclockwise direction by a motor 25 and cooperates with the roller 24 to form a fold or bend in the sheet S. As in the previously described embodiment, the forward edge of the sheet S is gripped by the highly frictional composition of the roller 26 in order to carry the forward edge of the sheet into the nip between the rollers 26 and 28. Upon this occurrence, the sheet S is pulled at a fast rate across the bottom of the plate 21 and feeds the sheet from the bottom of the stack. As was the case with the roller 12, the restraining roller 24 is provided with a slip clutch in order to permit overriding thereof when the sheet S is pulled by the rollers 26 and 28.

As in the embodiment disclosed in FIGURES 1, 2, and 3, the frame 27 and consequentially the feeder rollers 26 and 28 are actuated generally in a direction normal to the plane of the sheets in the stack 10 by a solenoid 29 which is connected to a control device 30 for imparting timed, periodic reciprocatory motion to the frame 27.

The operation of the embodiment of FIGURE 4 is exactly the same as the embodiment of FIGURES 1, 2 and 3 in that the adjacent feed roller 26 and the restraining roller 24, when the former is actuated by the solenoid 29 into engagement with the lowermost sheet of the stack, cooperates with the roller 24 to produce a fold or bend in the sheet S.

The speed of paper feeding for either embodiment of the invention may be varied by controlling the frequency of the periodic motion of the frames 16 or 27, in fact, the rate of reciprocatory motion imparted to the frames 16 and 27 is a direct function of the rate of paper feed. Each time that the adjacent feed roller, which in the embodiment of FIGURES l-3 is the roller 14, and in the embodiment of FIGURE 4, the roller 26, a sheet will be fed from the stack to which the feed roller is applied. Suitable control means may be utilized to control, say by manually actuating a knob, for conditioning the apparatus for paper feed operation at the rate of anywhere from 0 feed rate to 200 sheets per minute, or more.

It will be appreciated that the possibility of double feed or multiple feed during one actuation of the feed roller frames is eliminated since the adjacent feed roller is adapted to have one leading edge of one sheet gripped thereby at any one time. The movement of the adjacent feed roller away from the next sheet in the stack will be simultaneous with the gripping of the leading edge of the 3,425,685 6 sheet then in process of being fed. In fact the movement of the sheet during engagement therewith, said one roller the adjacent feed roller away from the stack actually helps being adapted to move the sheet until the leading edge to produce the movement of the leading edge therewith thereof moves past the point of tangency therebethus ensuring that a second sheet will not be able to be fed. tween whereupon the flexing force produced by said What is claimed is:

bend will force the leading edge against said'one 1. Sheet handling apparatus comprising: 5 roller and cause the edge to be carried to said nip a sheet handling device adapted to support a stack of to be advanced by said feed rollers out of the stack of sheets to be fed therefrom in a fixed plane, h ts,

a sheet restraining mechanism having an element ena frame t t bl Supporting id f d toners,

gageahle with the Stach intermediate the Sheet h said control means having an actuator device responsive and arranged restram each of the sheets agaulst to discrete electrical signals operatively connected to movement in said plane parallel to the other sheets in the frame to impart reciprocatory movement 0f the the stack and in a direction toward the rearward end frame relative to Said plane, of.the Stack said sheet restraining element comprises a roller rotataa pair of feed rollers arranged transversely of the stack bl 1 h t f f d with their axes parallel and being driven for advance on y m a Opp 081 e t a o Sal ee ing a sheet when in the nip therebetween, one of said roller rollers being rotatalble in a direction to produce rear- References Cited Ward movement of a sheet in said plane, when in engagement therewith UNITED STATES control means operatively connected with said pair of 734 172 7 1903 Hamilton 271 23 nollers for periodically moving the same toward said 3 325 1 4 19 7 Kedzierski 271 21 plane to place said one roller into engagement with a sheet thereat, thereby causing a bend in the sheet EDWARD A. SROKA, Primary Examiner.

between said element and said one roller, said bend being produced by the restraining effect of said element and the force produced by said one roller upon US. 01. X.R.

Images