US3507489A - Sheet feeding apparatus - Google Patents

Description

April 21, 1970 Filed Sept. 5, 1967 F. W. WILSHIN ET AL SHEET FEEDING APPARATUS 4 Sheets-Sheet 1 @wiiW Jud: will); add;

W441 ta,- 4 4441 April 21, 1970 F. w. WILSHIN ETAL 3,507,489

SHEET FEEDING APPARATUS Filed Sept. 5. 1967 4 Sheets-Sheet 2 MM 5% wag Lu m MpL-GJU A o-1.0mm,

April 21, 1970 Filed Sept. 5, 1967 FIG-13.

F. w. WILSHIN ET AL SHEET FEEDING APPARATUS 4 Sheets-Sheet 5 April 21, 1970 F. w. WILSHIN ETAL 3,50

SHEET FEEDING APPARATUS Filed Sept. 5, 1967 4 Sheets-Sheet 4.

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mAMw M 9,4 film M United States Patent U.S. Cl. 271-46 8 Claims ABSTRACT OF THE DISCLOSURE In a sheet-feeding apparatus wherein sheets pass from a high-speed conveyor to a low-speed conveyor, a roller is intermittently operated to press a passing sheet against the low-speed conveyor to ensure its deceleration; means are also disclosed for holding the roller against the sheet and stopping the low-speed conveyor so that gaps between successive sheets can be closed.

This invention relates to sheet feeding apparatus e.g. for use in paper cutters and like machines.

In apparatus for feeding sheets, e.g. of paper, high feed speeds are liable to be employed, but at the delivery end of a machine, where sheets are required to be stacked, it is necessary to decelerate the sheets before they reach the layboy or other stacker if damage is to be avoided and a neat stack formed. It has become a common practice to accomplish desired deceleration by transferring the sheets from a high-speed conveyor to a low-speed conveyor, making provision for overlapping of the successive sheets as necessary.

The low-speed conveyor need only be short, provided it can be ensured that each sheet arriving on the lowspeed conveyor is compelled to adopt the low speed of said conveyor before leaving it. Most economically and conveniently, the low-speed conveyor is a simple conveyor belt, and an obvious expedient for compelling sheets to conform to its speed is to provide a roller or belt above and in contact with the low-speed conveyor so that each sheet is held against the belt. Such a simple arrangement is not however satisfactory when sheets arrive on the lowspeed conveyor at high speed as the leading edge portion is suddenly slowed while the following parts of the sheet are free, hence the sheets tend to buckle undesirably.

According to the invention, we provide sheet feeding apparatus comprising a high-speed conveyor arranged to deliver sheets in succession to a low speed conveyor, and a roller for pressing said sheets against said low-speed conveyor so as to compel the sheets to decelerate to the speed of said low-speed conveyor, in which said roller is carried on a mounting permitting movement of the roller towards and away from said low-speed conveyor and said mounting is associated with drive means arranged to urge said roller towards said low-speed conveyor during a part of the time required for each sheet to pass said roller and to hold said roller away from said conveyor at other times.

Conveniently the roller is carried on one or more pivoted members, e.g. bell-cranks, each such member having a bearing for the roller at one of its ends, the other end of at least one of said members carrying a cam follower riding on a cam profiled to cause desired movement of the roller. The cam or each cam may be a face cam giving a positive drive to the roller in each direction, but preferably the cam is an edge cam and the pivoted members are provided with one or more springs arranged to urge each of the followers against the cam or cams. The cam or cams are preferably so driven that the roller is ice urged towards the conveyor as the trailing portion of each sheet is passing the roller.

Alternatively, the roller may be carried upon a slidable member mounted for rectilinear movement towards and away from the low-speed conveyor; the cam may then operate directly upon the slidable member carrying the roller, or may act upon a pivoted cam follower engageable with said rectilinearly slidable member.

Further means may also be provided for urging the roller towards the conveyor, independently of operation of the drive means and simultaneously stopping the conveyor. This enables a sheet to be additionally delayed, as is required when overlapping of sheets is desired and an unusually large gap is detected between successive sheets (e.g. where a sheet has been removed for inspection or because it is faulty). Such further means preferably includes a pneumatic actuator which may be linked to the mounting for the roller or may operate a separate roller.

It will be appreciated that apparatus embodying the invention can be operated satisfactorily when sheets are fed two or more at a time in superposed relation, as each group of superposed sheets is nipped between the lowspeed conveyor and the roller while the roller is urged towards the conveyor. The low-speed conveyor preferably comprises a conveyor belt but may alternatively comprise driven rollers protruding through a polished plate.

In order that the invention may be well understood, we will now describe preferred embodiments thereof, illustrated in the accompanying diagrammatic drawings in which:

FIGURE 1 is a diagrammatic side elevation of a sheetfeeding apparatus in association with a layboy;

FIGURES 2A, 2B and 2C show three alternative arrangements of part of the apparatus of FIGURE 1;

FIGURE 3 is an end view of a fourth alternative arrangement; and

FIGURE 4 shows yet another alternative arrangement, and includes a sectional view of a pneumatic actuator.

FIGURE 1 shows apparatus for feeding paper sheets from a cutter 1 to a layboy 2 in which the sheets are to be stacked. 'Said apparatus comprises an upper belt 3 and lower belt 4 arranged to receive sheets from the cutter 1 and carry such sheets at high speed to the vicinity of the layboy 2. The belts 3, 4 may be of substantial length and in association with such belts we may provide ancillary equipment, such as inspection devices and means for deflecting faulty sheets, so that the belts 3, 4 may in practice be discontinuous but this is irrelevant to the present invention.

The high speed belts 3, 4 terminate at rollers 5, 6 (their delivery end) respectively situated a short distance from the layboy 2 and as sheets 7 emerge from between the belts 3, 4 they pass over a fixed bridge member 8 onto a slower-moving belt 9 extending to the entrance to the layboy 2, whereafter the sheet enters the layboy and joins a stack forming therein in conventional manner.

To ensure that each sheet 7 is compelled to decelerate to the speed of belt 9 as it passes thereover, a pair of rollers 10, 11 are provided in association with said belt 9. Roller 10 is an idler roller lying under the upper run of belt 9 and roller 11 is also an idler roller and is journalled in one end of a bell-crank lever 12. The lever 12 is carried on a pivot shaft 13 and provided with a spring 14 arranged to urge said lever 12 clockwise (as seen in the drawing) so that a cam follower 15 at its other end is maintained in contact with a cam 16 carried on a shaft 17. The shaft 17 is connected by any suitable transmission T to the cutter 1 so that cam 16 revolves in synchronism with the operation of the cutter 1, the relative timing and the form of cam 16 being such that as soon as the trailing edge of each sheet 7 leaves belts 3, 4 but While the trailing part of the sheet is still passing below roller 11, the cam 16 moves bell-crank lever 12 anti-clockwise and thus causes roller 11 to press the sheet 7 against belt 9; the sheet 7 and belt 9 are thus nipped between rollers 11, 10 and the sheet 7 is forced to conform to the speed of the belt 9 by virtue of the enhanced frictional contact between said sheet and said belt. Transmission T preferably includes an adjustable coupling DC to serve as a phasing control, allowing adjusement of the timing of cam 16 relative to the cutter 1.

The cam 16 is so formed as to maintain the nip between rollers 11, 10 for only a short time but once decelerated the sheet 7 naturally continues at the speed of be t 9. Bell crank level 12 is not a rigid lever, but its two parts are connected by a spring 18 so as to allow a certain resilience in roller 11 when the latter is engaged with sheets 7. The spring-biased lost-motion connection thus provided by lever 12 allows for variation in the total thickness of sheets 7.

It will be appreciated that the appearance described, while simple, is yet effective to provide a positive deceleration of the sheets and thus secure their entry into the layboy 2 at the proper speed without any necessity for stopping the movement of each sheet at any stage before it is actually stacked.

It is a particular advantage of apparatus embodying the invention that it cannot only deal with single sheets, but functions equally well when the cutter 1 (or other apparatus providing the sheets to be fed) produces two or more sheets simultaneously so that when the rollers 11, 10 nip, two or more superposed sheets are gripped between the roller 11 and belt 9. In the drawing, it will be seen that the sheets 7 are in fact shown in superposed pairs. The nip of rollers 11, 10 gives rise to increased friction between adjacent sheets as well as between the lowermost sheet and the belt 9, so that all the superposed sheets are simultaneously decelerated to the speed of the belt 9 without change of their relative positions. The sheets (or groups of superposed sheets) may be overlapped each with the next, in which case the apparatus may be provided with devices for maintaining such overlap.

Where overlap is required to be maintained, it is usua ly desirable to provide means for detection of any gap between successive sheets which will prevent proper over lapping, and for this purpose a detector 19 such as a photoelectric scanner may be provided near the delivery end of the high-speed belts 3, 4. (It will be appreciated that said belts 3, 4 may each, as is customary in the art, comprise a number of relatively narrow belts at spaced positions across the width of the apparatus i.e. normal to the plane of the drawing, and the detetor 19 may be mounted between an adjoining pair of said narrow belts).

The detector 19 may be connected to a solenoid 20 (FIGURES 2A, 2B) controlling a compressed air source 21 supplying a pneumatic actuator 22 (comprising a cylinder in which a ram is operable) via pipes 23. In the arrangement of FIGURE 2A, there is a bell-crank lever 12a generally similar to bell-crank lever 12 (FIGURE 1) but having an extension 12!) beyond the cam follower 15, said extension carrying a block 120 engageable by (but not connected to) the ram of pneumatic actuator 22. Thus either the actuator 22 may operate the lever 12a, lifting follower 15 away from cam 16, or cam 16 may operate lever 12a, lifting block 12c away from said ram.

In the arrangement of FIGURE 2B, instead of the bellcrank lever there is a rectilinearly slidable member 24 carrying roller 11, the member 24 being provided with a return spring 25. A centrally-pivoted cam follower 26 has one end engageable with cam 16 and the other end resting between the member 24 and the ram of pneumatic actuator 22.

In both the arrangement of FIGURE 2A and that of FIGURE 2B, whenever the detector 19 detects a gap between successive sheets such as to require operation of roller 11 independently of cam 16, the solenoid 20 causes source 21 to supply compressed air to the pneumatic actuator 22 so that the ram of the latter extends; this causes bell-crank lever 12a to turn (FIGURE 2A) or member 24 to be depressed (FIGURE 2B), the cam follower 15 or 26 respectively moving away from cam 16, so that in either case the roller 11 is lowered regardless of the position of cam 16 and is held in the lowered position until the air supply from source 21 is reversed under control of detector 19 and solenoid 20 so that the ram of actuator 22 retracts; whenever said ram is retacted as shown, however, it will be apparent that roller 11 will be operated regularly by cam 16 as in the arrangement of FIGURE 1.

FIGURE 2C illustrates an arrangement in which provision is made for regular operation only, but the cam 16 is not used. In place of said earn, i.e. secured to the shaft 17 is a pair of cross-members 27 carrying between them a pair of rollers 11a, 11b. It will be seen that as the shaft 17 is rotated clockwise as indicated by the arrow, the rollers 11a, 11b will alternately come into a position corresponding to the lowered position of roller 11 '(FIG- URES 1, 2A, 2B), and thus produce the same effect as roller 11 operated by cam 16. Naturally, with this arrangement, the transmission T (FIGURE 1) will need to have a different ratio as the rollers 11a, 11b are effective twice per revolution of the shaft 17, whereas cam 16 as shown is only a single-lobe cam giving one operation of roller 11 per revolution.

All three of FIGURES 2A, 2B, 2C also show a further modification, as compared with FIGURE 1, in that the belt 9 is omitted. In its place is a polished stationary plate 9a through which a roller 10a protrudes, the roller 10a taking the place of roller 10 but being a driven roller, rather than an idler roller; the roller 10a and plate 9a together serve as the low-speed conveyor.

In the arrangement of FIGURE 3, there is again shown a low-speed conveyor of the form just described; as FIG- URE 3 is an end view, it shows three rollers 10a, each protruding through the plate 9a, as representative of a larger number of such rollers located at spaced positions across the width of the apparatus. However, the arrangement of FIGURE 3 differs from those already described in that separate means are provided for retarding sheets regularly and for retarding sheets under control of the detector 19 (FIGURE 1).

Above the first and third of the rollers 10a shown are rollers 11c operated by cams 16 on shaft 17 through rectilinearly slidable members 24a tfitted with return springs 25a, i.e. as in FIGURE 2B except that cam followers 26 and pneumatic actuators 22 are not provided. The central roller 11d, in contrast, has no associated cam 16 or related parts, but is carried directly by the cam of a pneumatic actuator 22a; no air connections to said actuator are shown in FIGURE 3 but it will be understood that it is connected to a source 21, controlled by detector 19 through solenoid 20, exactly as are the actuators 22 of FIGURES 2A and 2B.

The rollers 10a of FIGURE 3 are carried by a shaft 28 which is driven via a clutch 29, said clutch being controlled by detector 19 (FIGURE 1) via a control connection indicated diagrammatically at 30. Also, said shaft 28 has a brake 31, controlled by detector 19 via a control connection 32. Such an arrangement is also provided for rollers 10a of FIGURES 2A and 2B, and the control connections 30, 32 are such that whenever the actuators 22 or 22a are supplied with air, the clutch 29 disengages and the brake 31 stops shaft 28, these operations being reversed whenever the rams of the actuators are caused to retract. This secures that anysheet passing under rollers 11c and 11d (or rollers 11) when a gap causes the actuators 22 or 22a to operate is actually stopped, rather than merely retarded to the speed of the low-speed conveyor. A similar arrangement may be used for stopping the sheet when a belt 9 is used as in FIGURE 1, the clutch and brake then being associated with the belt drive.

Lastly, FIGURE 4 shows an alternative arrangement in which cam 16 operates a centrally-pivoted cam follower 26a which influences a roller 11:: through a pneumatic actuator 22b.

The actuator 22b comprises a fixedly-mounted cylinder 33 in which a sleeve 34 is slidable; upper and lower end caps 35, 36 are secured to the sleeve 34. An inner sleeve 37 is slidable within sleeve 34, and a ram 38 is in its turn slidable within the inner sleeve 37. The cylinder 33 has three air inlets, a first inlet 39 through which air may be supplied between the outer sleeve and the upper end of the inner sleeve; a second inlet 40 for air supply between the inner sleeve and the ram; and a third inlet 41 for air supply between the outer sleeve and the bottom end of the inner sleeve. A lower closure ring 42 is secured to the cylinder 33.

Constant air pressures are applied at the inlets 40, 41, respectively causing the ram 38 to be urged towards its lowermost position relative to the inner sleeve 37 and the latter to be held in its uppermost position relative to the outer sleeve. When the actuator 22b is required to lower the roller 11e (i.e. when a gap is detected by the detector 19 as before) the inlet 39 is supplied with air at sufficiently high pressure to drive down the inner sleeve 37 taking the ram 38 with it against the constant pressure applied through inlet 41; when the roller He is required to return, the air supply to inlet 39 is discontinued and the constant pressure applied through inlet 41 causes the inner sleeve 37 (with ram 38) to return to its uppermost position.

The ram 38 is normally maintained in its lowermost position, relative to the inner sleeve, by the constant air pressure applied above it via inlet 40 but it will be apparent that if anything opposes the descent of roller 11e (e.g. a number of superposed sheets or, even, an operators finger) then the roller He is not forced down, with possibly damaging results, with all the power available in the apparatus but will cease descending .(i.e. will rise relative to the inner sleeve 37) as soon as the reaction from whatever opposes the descent of said roller equals the force exerted on the top of ram 38 by the air pressure applied via inlet 40. It will be appreciated that this is a valuable safety feature and provides automatic adjustment of the apparatus for variations in the number and/or thickness of sheets being fed. The arrangement of ram 38 to be slidable within sleeve 37, with a constant air pressure therebetween, provides a pneumatically-biased lost-motion connection to the roller 112, with a constant limiting thrust as the roller He cannot apply a greater force to the paper (or anything else) under it than the thrust generated by the air pressure acting on the top of the ram 38.

Whenever air pressure is applied via inlet 39, it will naturally tend to lift the outer sleeve 34 as well as causing the inner sleeve 37 to descend. The upper cap 35 of the outer sleeve is therefore maintained in contact with the cam follower 26a. It will be noted that the latter is provided with an adjustable abutment screw 43 so that the range of movement of the outer sleeve 34 may be set as desired.

It will be appreciated that where, as is common, two or more streams of sheets are being fed along parallel paths into a single layboy, at least one roller 11 will be provided for each stream of sheets; moreover, in such a case it is desirable to provide a separate detector 19 and associated parts for each stream, together with separate control of the drive to the belt 9 or rollers 10a for each stream, as gaps between successive sheets are likely to occur at different times in the different streams.

What we claim as our invention and desire to secure by Letters Patent is:

1. Sheet feeding apparatus comprising a high-speed conveyor, a low-speed conveyor arranged to receive sheets delivered in succession by the high-speed conveyor, a roller for pressing said sheets against the low-speed conveyor so as to compel the sheets to decelerate to the speed of said low-speed conveyor, a slide mounting for the roller permitting rectlinear movement of said roller towards and away from the low-speed conveyor, and drive means associated with said mounting, said drive means being arranged to urge said roller towards said low-speed conveyor during part of the time required for each sheet to pass said roller and to hold said roller away from said low-speed conveyor at other times.

2. Apparatus as claimed in claim 1 in which the mounting comprises a rectilinearly slidable member carrying the roller, and the drive means includes a cam operating directly upon said member.

3. Apparatus as claimed in claim 1, in which said drive means includes a pivoted cam follower engageable with the rectilinearly slidable member and a cam engageable with said cam follower.

4. Apparatus as claimed in claim 1, including further means for pressing the sheets against the low-speed conveyor independently of operation of the drive means and for simultaneously stopping said low-speed conveyor.

5. Apparatus as claimed in claim 4, including a gap detector associated with the high-speed conveyor and arranged to control operation of said further means.

6. Apparatus as claimed in claim 5, in which said further means includes a pneumatic actuator linked to the mounting for the roller.

7. Apparatus as claimed in claim 5, in which said further means includes a pneumatic actuator, and a separate roller operated by said pneumatic actuator.

8. Apparatus as claimed in claim 5, in which said further means includes a pneumatic actuator and said drive means includes a cam and a cam follower associated with said cam, said actuator being arranged to function as a pneumatically-biased lost-motion connection between said cam follower and the roller.

References Cited UNITED STATES PATENTS 567,264 9/ 1896 Child 27l46 985,014 2/1911 Dexter 27l46 1,142,786 6/1915 Kneppler 27l46 3,034,780 5/1962 Stelling 27 l-46 X 3,315,956 4/1967 Lyman 27 I46 FOREIGN PATENTS 1,243,966 6/1967 Germany.

EDWARD A. SROKA, Primary Examiner U.S. Cl. X.R. 27l-76

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