US2960334A - Sheet feeding mechanism for duplicating machines - Google Patents

Description

Nov. 15, 1960 c. TROMBETTA SHEET FEEDING MECHANISM FOR DUPLICATING MACHINES Filed Jan. 6. 1959 INVENTOR.

CARLO TPOMBETTA ATTORNEYS nited States SHEET FEEDING MECHANISM FOR DUPLI- CATING MACHINES Carlo Trombetta, Caluso, Italy, assignor to lug. C. ()livetti 8: C., S.p.A., Ivrea, Italy, a corporation of Italy Filed Jan. 6, 1959, Ser. No. 785,249

Claims priority, application Italy Jan. 8, 1958 7 Claims. (Cl. 271-62) This invention relates to the automatic sheet feeding mechanisms for cyclically operable duplicating machines. More specifically, the object of the invention relates to an improved device for so raising the paper tray as to bring the top sheet of the sheet pile to a predetermined, constant level before being fed during a machine cycle.

In the known devices the tray is usually moved upwards by an intermittently operated mechanism, such as a pawl and a ratchet wheel mechanism, whereby the sheet level will oscillate between two consecutive steps of said upward movement, each step being effected a predetermined number of machine cycles after the next preceding step.

An object of the invention is to provide a paper tray raising device for cyclically conditioning the sheet pile to bring the top sheet to .a rigorously constant level before being fed.

Another object of the invention is to provide in such a device a bail for positively setting during a portion of each machine the level of said top sheet.

According to the invention in an automatic sheet feeding mechanism for cyclically operable duplicating machines, I now provide a device for conditioning the sheet pile to bring the top sheet to a constant level before being fed, said device comprising a substantially vertically movable tray for said pile, a spring urging said tray upwards, a bail cyclically operable for being set to a position arresting said pile at said level, and a locking member for said tray, said locking member being operable concurrently with said bail to unlock said tray to enable same to be moved by said spring until said pile is arrested by said bail.

Further objects, features and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, wherein:

Fig. l is a partial right-hand sectional view of a duplicating machine having an automatic sheet feeding device embodying the improvements according to the invention;

Fig. 2 is a perspective view of a detail of Fig. 1.

With reference to Fig. 1, the numeral 3 indicates the conventional master sheet supporting drum of the machine. The drum 3 is rotated by a cyclically operable main shaft 4 which is also adapted to control by known means the conventional sheet feeding rollers 6 and the conventional impression roller 5. During each machine cycle the feeding rollers 6 will feed the top sheet of the sheet pile 7 towards the drum 3, whereas the impression roller will force the so-fed sheet against the master sheet supported by the drum 3.

The sheet pile 7 is supported by a tray 8 which will be progressively raised to bring the top sheet to an operating position with respect to the rollers 6.

According to a feature of the invention the tray 8 is carried by a linkage comprising an arm 10 pivoted on a stationary pin 50 of the machine frame 14 and provided with a pin 51 slidably mounted in a horizontal slot 2,969,334 Patented Nov. 15, 1960 53 of the tray 8. Pivoted on the middle point of the arm 10 is a lever 11 having a pair of arms each half as long as the pivoted arm 19. The free end of one arm of the lever 11 is provided with a pin 52 engaging a vertical slot of the tray 8; the free end of the other arm of said lever is provided with an element or pin 12 slidably mounted in a slot 13 of the machine frame 14. The slot 13 is arranged according to a direction intersecting the pivot 50 and inclined with respect to the straight line intersecting the pivot 50 and the pin 52 an angle half as wide as the angle formed by the two arms of the lever 11. In the drawings, said straight line is arranged vertically, the angle formed by the two arms amounts to degrees, and the angle between the direction of the slot 13 and the vertical direction amounts to 45 degrees. The arm 10 is normally urged counterclockwise by a spring 9, whereby the tray 8 is urged upwards.

By inspecting the geometrical features and sizes of the arm 10 and lever 11 it will be understood that a rotation of the lever 16 causes a parallel and rectilinear movement of the tray 8. More particularly, when the arm 16 is rotated counterclockwise the pin 51 will slide in the horizontal slot 53 and the pin 12 of the lever 11 will be forced to obliquely move upwards along the inclined slot 13, while the pin 52 will move vertically maintaining the tray 8 horizontal.

Secured to the main shaft 4 is a cam 15 co-operating with a cam follower 17 of a lever 13 pivoted at 19. The lever 18 is urged clockwise by a spring 16 and carries a transverse bail 20 as long as the transverse size of the tray 8. During each cycle of the shaft 4, prior to the sheet feeding action of the rollers 6, the portion 21 of the cam 15 rocks the lever 18 counterclockwise to positively set the bail 20 in the position shown with broken lines in Fig. 1. This position of the bail 20 determines a constant level wherefrom the top sheet of paper should be fed to the drum 3 and at which the bail 20 is adapted to arrest the sheet pile 7 when the tray 8 is moved upwards, as will be hereinafter described.

According to another feature of the invention, normally the pin 12 of the lever 11 contacts the edge of a locking member such as a spirally shaped cam member 22 which thus normally locks the tray 7 against the urge of the spring 9. The cam member 22 is rockably mounted on a shaft 23 secured to the machine frame 14. The axis of the shaft 23 is intersected by the aforesaid inclined direction of the slot 13. The pin 12 results thus movable radially with respect to the shaft 23 and the cam member 22.

Integral with the cam member 22 is a hub 24 (Fig. 2) having connected thereto an end of a flexible band 25. A spring 26 normally urges the band 25 upwards whereby the cam member 22 is urged to rock counterclockwise to contact the pin 12. The spring 26 is so strong as to enable the cam member 22 to balance the upward thrust of the tray 8 caused by the spring 9.

Furthermore, pivoted on the shaft 23 is a lever 27 having integral therewith a hub 28. A helicoidal spring 29 is normally wound around the hub 28 and a portion of the hub 24. One end 31 of the spring 29 engages a hole formed in a bent lug 32 of the lever 27, the other spring end 33 contacts a projection 34 of a plate 35 secured to the shaft 23. Normally the projection 34 anguare . larly forces the end 33 upwards to slightly unwind the spring 29, whereby the cam member 22 is disconnected from the lever 27.

Integral with the lever 27 is a projection 36 (Fig. 1) adapted to cooperate with a pin 37 of a lever 38 pivoted on a stationary shaft 39. The lever 38 is provided with a cam follower 40 urged by a spring 41 to contact the edge of a cam 42 secured to the main shaft 4. By the urge of a spring 43 the lever 27 normally contacts a pin 44 of a crank-lever 45 secured to a manipulative knob 46 shown with broken lines in Fig. 1.

The device operates as follows:

During each cycle of the main shaft 4, prior to the rightward feeding of the top sheet by the rollers 6 and concurrently with the operation of the bail 20 when being set in the constant level position shown 'by broken lines in Fig. l, the cam 42 will rotate the lever 18 counterclockwise. The pin 37 will thus engage the projection 36 and rock the lever 27 clock-wise. The lug 32 of the lever 27 first winds up the spring 29 to rigidly connect the hub 24 with the hub 28 and then rocks through a certain angle the cam member 22 together with the lever 27, against the urge of the spring 26. The spiral edge of the cam member 22 retracts from the pin 12 of the lever 11, thus unlocking the tray 8 which is now raised by the spring until the sheet pile 7 is arrested by the bail 20. Since the bail 20 is maintained in the set position by the portion 21 of the cam 15, in the corresponding portion of the machine cycle the level of the paper is positively set and the top sheet reaches a rigorously constant level before being fed by the feed rollers 6.

Thereupon the cam 42 enables the lever 38 to be returned to rest before the portion 21 of the cam 15 has left the lever 18. The lever 38 thus releases the lever 27 which is restored by the spring 43, whereby the spring 29 is unwound and the hub 24 is disconnected from the hub 28. The spring 26 may now rock the cam member 22 counterclockwise until its edge will contact the pin 12. Concurrently the cam 15 enables the bail 20 to be raised by the urge of the spring 16, the tray 8 being now locked by the cam member 22 with the top sheet of the pile 7 occupying the constant level position. Finally, the rollers 6 will be operated to feed the top sheet rightwards, the pile 7 being now free from the bail 20.

When a new sheet pile is to be put on the tray 8, the latter may be manually depressed against the urge of the spring 9. The pin 12 sliding in the inclined slot 13 moves away from the cam member 22. This latter is promptly rocked counterclockwise by the spring 26 until it contacts the pin 12 once more to lock the tray 8 in its new position.

If it is now desired to manually raise the tray, the knob 46 may be manually turned counterclockwise through a little angle. The pin 44 of the crank-lever 45 then rocks the lever 27 in a similar manner as does the pin 37, whereby the cam 22 will be rocked clockwise. By the urge of the spring 9 the tray 8 is now raised through an extent corresponding to said angle, irrespective of the cyclical operation of the machine, including the bail 20. If the knob 46 is turned repeatedly, the tray 8 may be stepwise raised to any desired position, even higher than the constant level position of the bail 20 shown by broken lines. However, in this case during the first ensuing cycle of the main shaft 4 the bail 20 will positively push the tray 8 downwards against the urge of the spring 9, whereby the sheet pile 7 will bring the top sheet to the constant level position.

From the above description it will be understood that if the cam member 22 is rocked clockwise against the urge of the spring 26 either by operation of the cam 42 or by hand, the pin 12 will follow the edge of the cam member 22 and the tray will be raised. On the contrary, if the tray 8 is manually moved downwards against the urge of the spring 9, the spring 26 will rock the cam member 22 counterclockwise until being arrested by the pin 12. Therefore, the cam member 22 forms an adjustable locking member for the tray 8.

It will be apparent that the frictional force generated by the movement of the pin 12 relatively to the edge of the cam member 22 enables the two springs 9' and 26 to remain mutually balanced irrespective of the variable weight of the sheet pile 7.

The cam member '22 is provided with a projection 48 adapted to operate a stop means, not shown in the draw ings, upon a full clockwise revolution of the cam member 22, in order to automatically stop the duplicating machine when the sheet pile 7 is going to be exhausted.

It will be understood that many changes may be made in the above construction, and different embodiments of the invention could be made Without departing from the scope thereof. For example, to prevent the spring 29 from being excessively tensioned by the lug 32 when transmitting rotation to the cam member 22, the lever 27 may be provided with a projection, not shown in the drawings, which, after a few degrees of rotation winding up the spring 29 to rigidly connect the cam member 22 with the lever 27, is adapted to push the spring end 33 upwards whereby the further rotation of the lever 27 will merely bodily rotate the spring 29 and the cam member 22.

What I claim is:

1. In an automatic sheet feeding mechanism for cyclically operable duplicating machines having a feeding member operable for engaging the top sheet of the sheet pile to feed said top sheet, a device for conditioning the sheet pile to bring the top sheet to a constant level before being fed, said device comprising a substantially vertically movable tray for said pile, a spring urging said tray upwards, said spring being sufiiciently strong to overcome the weight of the tray and the sheet pile, a bail cyclically operable in timed relation with said feeding member for being positively set toa position arresting said pile at said level against the urge of said spring, and an undiscontinued locking member for locking said tray against the urge of said spring irrespective of said sheet pile, said locking member being cyclically operable concurrently with said bail to unlock said tray to enable same to be moved by said spring until said pile is arrested by said bail.

2. In an automatic sheet feeding mechanism for cyclically operable duplicating machines having a feeding member operable for engaging the top sheet of the sheet pile to feed said top sheet, a device for conditioning the sheet pile to bring the top sheet to a constant level before being fed, said device comprising a substantially vertically movable tray for said pile, a first spring urging said tray upwards said first spring being sufiiciently strong to overcome the weight of the tray and the sheet pile, a bail cyclically operable in timed relation with said feeding member for being positively set to a position arresting said pile at said level against the urge of said first spring, an element connected with said tray, an undiscontinued cam shaped locking member adapted to contact said element for locking said tray in any vertical position against the urge of said first spring irrespective of said sheet pile, a second spring normally urging said locking member to contact said element, said second spring being so strong as to enable said locking member to balance the upward thrust of said tray, and means cyclically operable concurrently with said bail to disable said second spring, whereby said tray may be moved by said first spring until said pile is arrested by said bail.

3. In an automatic sheet feeding mechanism for cyclically operable duplicating machines having a feeding member operable for engaging the top sheet of the sheet pile to feed said top sheet, a device for conditioning the sheet pile to bring the top sheet to a constant level before being fed, said device comprising a substantially vertically movable tray for said pile, a first spring adapted to urge said tray upwards said first spring being sufficiently strong to overcome the weight. of the tray and the sheet pile, a bail cyclically operable in timed relation with said feeding member for being positively set to a position arresting said pile at said level against the urge of said first spring, an element connected with said tray, a spirally shaped rockable cam member adapted to contact said element for locking said tray in any vertical position against the urge of said first spring irrespective of said sheet pile, said element being radially movable with respect to said locking member, a second spring normally urging said locking member to so rock as to contact said element said second spring being so strong as to enable said locking member to balance the upward thrust of said first spring, and means cyclically operable concurrently with said bail for rocking said member against the urge of said second spring to unlock said tray, whereby said tray may be moved by said first spring until said pile is arrested by said bail.

4. A device as defined in claim 3, characterized by manual means for rocking said locking member against the urge of said second spring to enable the tray to be moved upwards by said first spring irrespective of the cyclical operation of the machine.

5. In an automatic sheet feeding mechanism for cyclically operable duplicating machines, a device for conditioning the sheet pile to bring the top sheet to a constant level before being fed, said device comprising a tray for said pile, a linkage for substantially vertically moving said tray, said linkage being formed of a pivoted arm slidably connected with said tray and a lever pivoted on the middle point of said pivoted arm and having a pair of arms each half as long as said pivoted arm, the free end of one arm of said lever being pivotally connected to said tray, the free end of the other arm of said lever being movable in a direction intersecting the pivot of said pivoted arm, a spring urging said linkage upwards, and cyclically operable means in said device for arresting said pile at said level.

6. A device as defined in claim 5, wherein said means are formed of a bail settable to a position arresting said pile at said level, an element secured to the free end of said other arm, a spirally shaped rockable cam member adapted to contact said element for locking said tray in any vertical position, said element being radially movable with respect to said locking member, a second spring normally urging said locking member to so rock as to contact said element, said second spring being so strong as to enable said locking member to balance said first spring, and means operable concurrently with said bail for rocking said member against the urge of said second spring as to unlock said tray, whereby said tray may be moved by said first spring until said pile is arrested by said bail.

7. A device as defined in claim 5, characterized in that said direction is inclined with respect to the vertical direction an angle half as wide as the angle formed by the two arms of said pair.

Brasseur Feb. 5, 1935 Carroll Feb. 22, 1944

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