US2335078A - Sheet feeding apparatus - Google Patents

Description

NOV. 23, 1943. H QSBORN 2,335,078

SHEET FEEDING APPARATUS Filed Nov. 26, 1941 3 Sheets-Sheet 2 Nov. 23, 1943. H. osBoRN SHEET FEEDING APPARATUS s sheets-sheet s Filed Nov. 26, 1941 [wz/faim* I M x m,

Patented Nov. 23, 1943 y 2,335,071; Q snaar rnnnmc APPARATUS Howard Osborn, Stapleton, Bristol, England, as-

signor to The Thrissell Engineering Company Limited, Bristol, England, a British company Application Noveieber ze, 1941, serial No. 420,579 In Great Britain December 18, 1940 (Cl. 2MP-8.5)`

` 11 Claims.

This invention concerns improvements in 'or relating to sheet-feeding apparatus of the kind in which sheet removal means is adaptedv to remove sheets from the` top of a pile carried by a support which is moved upwardly by an elevator to raise the pile towards a sheet feeding posi-f sheets or whe'n the individual sheets are of such a size as to make the pile, from which the sheets are to be fed, a relatively heavy pile to support. The present invention is particularly applicable to an apparatus for feeding sheets of solid fibre board or mill board to container-making'or other machinery. boards may be 24" high and the size of the boards such that the pile weighs approximately 11/2 tons. The weight of a grid to support such a pile would be in the region of 11,/2 hundredweights,

Whereas in apparatus of the kind described it has heretofore been customary manually to remove the support when the pile thereon has been exhausted, it will be appreciated that when dealing with a support the weight of which isA of the nature of 1% hundredweights, this is not va practical proposition. Consequently, in container making or other machines which operate upon such boards, the boards have been fed individually and manually to the machine. Manual feeding of the sheets naturally reduces the rate of o'utput of the machine and it is an object of the present invention to provide a sheet feeding apparatus capable of automatically feeding sheets of solid fibre board, mill board or other similar material from a pile.

It is, moreover, not practicable to employ'a sheet-feeding apparatus of the kind in which a following loaded support to the sheet feeding position.

Further according to the invention there is provided apparatus of the kind described wherein mechanism is provided for moving a support from a loading position to a position at which the support is engaged by an elevator arranged to move the support upwardly towards the posi p tion at which the sheet removal means is op- In some cases the pile of such sheets are fed from the bottom of a pile conf tained in a magazine hopper because the weight of the pile is such as to render likely the scarring of the liners of the boards during the pulling out of a board from the bottom of the Dile.

-For this reason, therefore, it is necessary to feed erative and past said latter position to a further position at which the support is engaged by delivery mechanism arranged to guide the support away from the elevator in a direction transverse to that in which the support is Imoved by the elevator. The elevator may be driven at different speeds whereby, when the last sheet of a pile has been removed from a support, the latter may be quickly moved past the position at which the sheet removaLmeans is operative while simultaneously a further support is raised to a position such that the sheet removal means may become operative on the pile on said further support. Wheels may be providedon the supports for moving the latter from the loading position to the elevating position.

The mechanism for moving the loaded support intolposition to ybe engaged by the elevator may include a conveyor-chain, said chain being caused to move when a support being raised by the elevator reaches a predetermined position whereby the newly loaded support is permitted to move into position to be engaged by the elevator.

Further according to the invention there is Vprovided apparatus of the kind described wherein a detector device is operatively connected with the driving means to stop the upward movement of the support when the top ofthe pile on said support reaches a given level and wherein means 'isloperative when the pile is exhausted to move the support upwardly out of range of the sheet Vremoval means and simultaneously to raise a further support having a pile of sheets to a position at which the sheet removal means can remove sheets from the said further support.

`Further according to the invention there is f provided apparatus of the kind described wherein a detector device is operatively connected with the driving means to stop the upward movement of the support when the top of the pile on saidv support reaches a given level and wherein means is operative when the pile is exhausted, to increase the rate of upward movement of the support so as to move the support upwardly out of range of the sheetI removal means and simulther support having a pile of sheets to a position at which the -sheet removal means can remove the sheets from said further support.

Further according to the invention there is provided apparatus of the kind described wherein the driving means includes both a .striking mechanism to stop and to start the driving means and a change-speed mechanism, `each of which mechanisms is independently operable by a detector device, the latter being arranged to operate the striking mechanism to stop the upward movement -of the support when the top of the pile on said support reaches a given level and to operate the change-speed l mechanism when the pile is exhausted to increase the speed of the elevator which thus carries the empty sup.- port above a sheet feeding position and. simultaneously raises a following loaded support having a pile of sheets to a sheet feeding position.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which- Figure 1 is a side elevation of an apparatus constructed according to the invention, the front fr'ame being omitted.

Figure 2 is an end elevation of Figure 1 partly in section.v

Figure 3 is a fragmentary view of a support.

Figure 4 is a plan of part of Figure 1 showing the driving arrangements.

Figure 5 is a fragmentary view of Figure 1 in the direction of the arrow A.

Figure 6 is a circuit diagram.

Referring to the drawings, a pile of sheets B (i. e. solid fibre boards) is placed upon a support which consists of a wheeled trolley I. The trolley comprises plate 39 carried on spaced channel irons 40 in which are mounted two axles 4I which are spaced apart and arranged to support flanged wheels 42. v l

The trolley I while in the loading position rests on rails 2 which engage the flanged wheels and by means to be described later is at the required instant moved or projected to a position to be engaged by an elevator. Its motion is retarded by a spring buffer 3 and recoil is prevented by a spring catch 4. 'I'he elevator comprises four rotatable vertical columns 5 on which are machined spiral endless cams or screws which engage rollers 8 on the trolley. thus causing the latter to ascend as the columns rotate. The spirals of the rear columns are of opposite hand to those in front in order that the horizontal forces or thrusts shall be equalised and other rollers 1 ride in vertical tracks 8 to further ensure stability. At the base of each column is xed a wormwheel 9 driven by a wormshaft I0 which is driven by chains Il and I2 (or I8) from an electrical motor 24 in the manner hereinafter described.

As the columns are rotated. the trolley is lifted oi! the rails 2 and is raised to a sheet feeding position as shown in Figure 1 at which sheet removal means is adapted to remove the top sheet of the pile and deliver it between -a pair of draw rollers I4 which feed the sheet to the container maker or other machine, for example along a conveyor belt 43. 'I'he sheet removal means may comprise a plurality of suckers I5 mounted on a sucker bar I6 which is slidably -mounted on arms I1 on which it is urged 'downwards by springs I8 but held upwards by rocking arms I9. The arms I1 swing about a pivot shaft 2II. the motion being effected by levers 44 and 45 and link 43 from a cam 41 on a camshaft 2|. The lever 44 is loosely mounted on a shaft 15. 'Ihe arms I9 are keyed to the shaft 'I5 and there is also fixed to this shaft a cam lever 16 having a roller at its end which engages a cam 11 ilxed on the camshaft 2l, see Figure 5. The resultant motion due to the action of the rocking arms I9, the arms I1 and the springs I8, is such that the suckers are first lifted to raise the top sheet from the pileand thereafter moved substantially horizontally to convey the leading edge of the sheet into the grip of the draw rollers I 4. These rollers consist of a rotatable lower roller which co-operates'with an oscillating upper roller in the customary. manner, the latter being operated by the lever 44. The roller I4 is driven from thecontainer maker or other machine by a chain or the like indicated at A18, Figure 1 and the camshaft 2I is driven from the spindle of the roller I4 by gear wheels 19 and 80, see Figure 5.

'I'he elevator is moved intermittently as described below and between each movement of the support (i. e., the trolley I) when the elevator is stationary, the suckers operate to remove several sheets in succession from the top of the pile. The rate at which the elevator, when moving, raises the trolley during the period in which the sheets are all removed therefrom by the suckers (i. e., the time taken to empty a trolley) is slightly greater than the rate at which the pile of sheets diminishes when the thickest sheets for which the machine is adapted are being fed at the greatest rate. To control the intermittent movement of the elevator, predetermined upper and lower levels of the top of the pile are chosen between which it is desired that the suckers shall be operative to remove sheets from the pile. These levels may for example be decided by a limit of plus or minus la. A detector-comprising a pivoted arm 22 carrying a roller 48 is arranged to determine when the pile is within the predetermined limits. Should the pile rise above the upper linut the outer free end of the detector arm is engaged by a swinging switch 23 which is moved towards the detector arm at every downward stroke of the suckers I5, thus closing an electrical circuit and causing the driving motor 24 to be stopped. The switch 23 is fixed to a shaft 8I journalled in the frame of the machine and a cam lever 82 is fixed at one end of the shaft. A roller on the end of this lever engages a crown cam 83 mounted on the camshaft 2I and shown in section in Figure 5. As the suckers remove sheets from the top of the pile, the roller 48 of the detector moves downwardly under the action of spring 49 until the top of the pile falls below the predetermined lower limit, at which time the detector arm engages an electrical contact 25 and makes'a circuit which restarts the motor.

When the pile of sheets on a support is exhausted, the detector roller 48 drops through a slot 26 (Figure 3) in the plate 39 thus causing the end of the detector arm to engage the aforesaid contact 25 and alsol a further contact 21 which makes a further electrical circuit in which is included a solenoid or electro-hydraulic device 28, Figure 4. The plunger of the solenoid is arranged, when the circuit is made, to actuate the ends of levers 29 which are pivoted at 50 between their ends and to rotate the levers about the said pivots. The other ends of the levers engage in collars 30 and 3| which are axially slidable on an lar comprises onepart oi a toothed clutch, the other part of which is iixed toa sprocket 32 or 53 connected by the chains I2 and I3' respectively to further sprockets 54 and 55 on the driving motor. When the solenoid plunger operates the levers 23 the two parts of the toothed clutch com prising the collar 3| are engaged while simulta-f neously the other clutch comprising the 'collar 30 is disengaged. A spring 58 moves the' parts in the reverse direction when the pull of the solenoid ceased/The sprocket 55 is directly mounted on the armature shaft of the motor while the sprocket 54 is xed to a shaft driven from the armature through reduction gearing contained in the casing 32 Figure 4. VDuring the period when the sheets are all being removed from a support, the intermittent movements of the elevator are at the lower speed because the driving of the elevators takes place through the reduction gearing but when the solenoid operates, the drive is direct from the armature shaft and thus the driving mechanism of the elevator is speeded up so that the elevator moves temporarily at an increased speed so as quickly to raise the trolley to a position above that at which the suckers are operative.

Slots 33 are provided inthe plate 39 of the trolley to permit the latter, when empty; to pass above the suckers.`

At some suitable predetermined position before the pile is exhausted, one of the rollers 6 on the trolley is arranged to engage a contact 34 Figure 2 and so complete an electrical circuit which causes a conveyor chain 35 to move one cycle and another conveyor chain 36 half of a cycle. motion can be obtained by driving the chains from the motor through an automatically disengaging clutch or other means known to the art. An arrangement of this kind is illustrated in Figures 2 and 4 where a further sprocket 51 is fixed on to the same shaft as the sprocket 54. A chain 58 on the sprocket 51 passes around further sprockets 59 and 60 mounted on counter-shafts 6| and 62 respectively. These counter-shafts are mounted in bearings in the machine frame and also have small gear wheels 63 and 64 respectively xed to them. These gear wheels drive larger gear wheels 65 and 66 respectively (the latter being driven through an idler 600) which are mounted on the shafts 61 and 68 of the chain conveyors 35 and 36. Each of these large gear wheels forms part of an automatically disengaging clutch which may be clutched to the shaft, bearing the large gear Wheel, by a key which is operatively connected to a lever 69. A bell crank lever 10 is pivoted at 1| and a solenoid 12 operates the bell crank lever to pull it out of the way of the lever 69 at the necessary times to permit the key to engage both gear wheel and shaft. A spring 13 returns the lever 69 to the position shown in Figure 4 when the contact 34 breaks, that is when the gear has been driven a suiiicient number of revolutions to impart the necessary movement to the corresponding chain conveyor.

When the iirst trolley is moved upwardly at an increased rate, after the pile carried thereby has been exhausted, the elevator simultaneously moves upwardly the next trolley which has previously been moved into position on the spiral columns. The increased rate of upward movement is maintained until the rst trolley has been moved out of range of the suckers and until the top of the pile on the succeeding trolley has been moved to a position to be operated by the suckers. A valve is provided in the air line so This that should the top sheet of the pile on the iurther trolley be curly" there will be no tendency for any one sucker to operate prematurely. This valve is shown diagrammatically at 14 Figure 4 and may be operated from one of the levera-aa indicated in the gure.

The trolley which has been raised above the suckers isfed (simultaneously with the moving in o( the next loaded trolley to the base of the elevator) away from the elevator along a track 31 by the chain conveyor 35 and then descends back again to the loading position being held and controlled by the chain conveyor 36 and the rear roller 6 of the trolley which rests upon the downwardly directed portion of the track 31.

In some cases the trolley may not be propelled by conveyor chains since it may be desired manually to wheel the loaded trolleys into position to be engaged by the elevator. In such a case the 420 electrical contact34 would operate an audible or visual signal which warns the operator that a loaded trolley should be pushed into the requisite position.

Figure 6 is a diagram showing the essentials of the circuit and the parts previously described with reference to the other iigures bear the same reference numerals. As drawn, the motor 24 is running and driving the machine through the reduction gear.

3o When the arm I22 engages the swinging switch 23, a solenoid 84 pulls up the arm of the switch 85 and stops the motor. But as soon as enough sheets have been fed so that the arm 22 comes into contact with the contact 25, the other solenoid 86 pulls down the arm of the switch 85 and the motor restarts. The switch is kept in the on and oli positions after the current in a solenoid ceases by a spring barrel 81 which holds the arm in either position over the dead centre.

When a pile of sheets is exhausted and the arm 22 engages both contacts 25 and 21 the motor restarts and at the same time the drive is altered to the direct or higher speed as the solenoid 28 becomes energised. l

The switch 34 is shown diagrammatically and consists of two halves sprung apart. As a trolley roller passes, it closes the switch and the automatic clutches are caused to operate.

What I claim as my invention and desire to claim by Letters Patent is:

1. Anarticle handling device of the class described comprising, in combination, a plurality of supports for piled articles adapted to pass successively through the device, means for successively raising said supports to a predetermined feeding level, means for successively feeding the articles from the top of the pile carried by the support currently at said level, means for raising said support when empty above said feeding position at an increased speed to permit said raising means to lift a subsequent support to said feeding position and driving means for said raising and feeding means synchronized for operation of said means at proper sequences and speeds.

2. In a feeding device of the class described, means for successively raising a plurality of supports upon which articles are piled to a predetermined level at which said articles are successively removed from the pile, and past said level at an increased speed to a further position, delivery mechanism for successively engaging said supports at said further position and moving them away in a direction transverse to that in which they are moved by said raising means, means for moving said supports from a loading position wherein the `articles are placed thereon to a position at which the supports are engaged and lifted by said raising means and driving means for said raising and feeding means synchronized for operation of said means at proper sequences and speeds.

3. A device as claimed in claim 1 in which means are provided for actuating saidraislng means slowly while adjacent said feeding level forV presenting the top sheets of the pile to the feeding means, and means for actuating said raising means more rapidly to deliver an empty.

l supports for piled articles, means for successively raising said supports to a predetermined feeding level, means for successively feeding the articles from the top of the pile carried by the support currently at said level, means for raising that support when -empty at an increased speed above said feeding position to permit said raising means to lift the next successive loaded support 'to said feeding position, driving means for said raising means, and detector mechanism operatively connected with said driving means to stop the raising means when the top of the pile on the support reaches a given level and when said pile is exhausted to raise the support upwardly out of the range of the feeding means and simultaneously raise the subsequent loaded support to article feeding position.

6. An article handling device of the class described comprising, in combination, a plurality of supports for piled articles, means for successively raising said supports to a predetermined feeding level, means for successively' feeding the :articles from the top of the pile carried by the support currently at said level, means for raising said support when empty above said feeding position to permit said raising means to lift a subsequent support to said feeding position, driving means for said raising-means, means for starting and stopping said driving means and means for increasing the speed of said raising means, and detector mechanism operatively connected with said driving means to start and stop the raising means 5 for maintaining the top of the pile at feeding level as the pile is depleted and when said pile is exhausted to raise the support upwardly at an increased speed out of the range of the feeding means and simultaneously to' rapidly raise a subsequent loaded support to article feeding position.

7. A device as claimed in claim 6 in which the detector mechanism includes a single detector element which is disposed in the path of the article in the pile and actuates both the starting and stopping means and the speed change means.

8. A device as claimed in claim 2 in which there are provided buffer means for cushioning the delivery of the loaded support to raising position, and latch means for retaining the support against rebound from said raising position.

9. A device as claimed in claim 1 in which the raising means comprises a rotatable screw threaded pillar, a projection on each of said supports, for engagement with the threads of the pillar, and means to prevent displacement of the support transversely while being raised.

10. An article handling device of the class described comprising in combination, a plurality of supports for piled articles, means for successively raising said supports to a predetermined feeding level, means for successively feeding the articles from the top of the pile carried by the supports currently at said level, means for raising said supports when empty above said feeding position to permit said raising means to lift a subsequent support to said feeding position, driving means for said raising means, means for increasing the speed of said raising means, and means for start ing and stopping said driving means to start and stop the raising means for maintaining the top of the pile at feeding level as the pile is depleted and when said pile is exhausted to raise the support upwardly at an increased speed out of the range of the feeding means and simultaneously to rapidly raise a subsequent loaded support to article feeding position.

l1. A device as claimed in claim 10 in which a single detector element is disposed in the path of the article in the pile and actuates both the starting' and stopping means and the speed change means.

HOWARD OSBORN.

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