US3294396A

US3294396A - Sheet feeding mechanism having a single control member for actuating a suction, air pressure, and pump means

Info

Publication number: US3294396A
Application number: US413100A
Authority: US
Inventors: Alfred J Staines
Original assignee: Harris Intertype Corp
Current assignee: Harris Graphics Corp
Priority date: 1964-11-23
Filing date: 1964-11-23
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27
Also published as: GB1065136A

Description

Dec. 27, 1966 A. J. STAINES 3,294,396

SHEET FEEDING MECHANISM HAVING A SINGLE CONTROL MEMBER FOR ACTUATING A SUCTION, AIR PRESSURE, AND PUMP MEANS Filed Nov. 23, 1964 2 Sheets-Sheet 1 INVENTOR. v AL RED J. STA/N55 ATTORNEYS Dec. 27, 1966 A. J. STAINES 3,294,396

SHEET FEEDING MECHANISM HAVING A SINGLE CONTROL MEMBER FOR ACTUATING A SUCTION. AIR PRESSURE, AND PUMP MEANS Filed Nov. 23, 1964 2 Sheets-Sheet 2 INVENTOR. ALFRED J. STA/N55 BY JL'ZZP'MlWZ QM WWW W ATTORNEYS United States Patent M SHEET FEEDING MECIIAI QISM HAVING A SINGLE CONTROL MEMBER FUR ACTUATING A SUC- TIGN, AIR PRESSURE, AND PUMP MEANS Alfred J. Staines, Shaker Heights, Ohio, assignor to Harris- Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed Nov. 23, 1364, Ser. No. 413,100 11 Claims. (Cl. 271-46) The present invention relates primarily to a sheet handling apparatus and, particularly, to a sheet feeding apparatus having suction separator means for feeding individual sheets from a pile and an air nozzle means for directing a stream of air under the sheet being handled to assist in the separation and feeding thereof.

In the operation of a sheet feeder having suction sheet separator means and an air nozzle means, it is important to be able to control the pressure of the air flowing through the air nozzle means. Of course, the air pressure should not be on until the suction in the separator means is on. Moreover, the air pressure is generally controlled or varied depending upon the stock being fed and the speed of feeding thereof. Without such a control, the sheets in the pile may be disarranged or the sheet being fed may be improperly fed. In particular, it has been found that as the speed of the feeding of sheets increases, the air pressure should increase. Therefore, when the feeder is being jogged or is operating at low speeds, such as when starting, the air pressure should be low or zero. As the speed of feeding increases, the air pressure likewise should be increased.

Prior art sheet feeding mechanisms utilize valves in the suction and air pressure lines which are adjustable to vary the suction and air pressure directed to the separator means and air nozzles. These valves are separately ad justed and are located at a position remote from the operators platform at which controls are located for controlling the speed of operation of the feeding mechanism. Thus, to make the valve adjustments, the operator must leave the operators platform, make the separate adjustments to the valves in the air and suction lines, and then return to the operators platform.

Accordingly, a principal object of the present invention is the provision of a new and an improved sheet feeding mechanism having suction separator means and air nozzle means and wherein valves for controlling the magnitude of the suction and the air pressure are adjustable by movement of a single control member.

Another principal object of the present invention is the provision of a new and an improved sheet feeding mechanism having suction separator means and air nozzle means and wherein valves for controlling the magnitude of the suction and the air pressure are adjustable by movement of a single control member accessible to an operator at the operators platform.

Another important object of the present invention is the provision of a new and an improved sheet feeding mechanism having suction separator means and air nozzle means and wherein valves for controlling the magnitude of the suction and the air pressure, as well as the pump means for creating the suction and air pressure, are controlled and actuated by a single movable control member located at the operators platform.

A further object of the present invention is the provision of a new and an improved sheet feeding mechanism having suction separator means and air nozzle means and valves for controlling the magnitude of the suction and the air pressure and means for adjusting the valves including separate cam members for actuating each of the valves and which are mounted for rotation with a shaft member which is rotatable by an operator on the operators platform.

3,294,396- Patented Dec. 27, 1966 A still further object of the present invention is the provision of a new and an improved sheet feeding mechanism having suction separator means and air nozzle means and individual valves which are cam actuated for con trolling the magnitude of the suction and the air pressure and wherein each of the valves has ports therein which are in communication with the atmosphere and with the suction or air pressure line, as the case may be, and wherein these ports provide for breaking the suction in the suction line and for the release of air pressure, respectively, and each valve includes a member movable to block communication between the ports and the suction or pressure line, respectively.

Further objects and advantages of the present invention will be apparent to those skilled in the art to which it relates from the following detailed description of the preferred embodiment thereof made with reference to the accompanying drawings forming a part of this specification and in which:

FIG. 1 is a schematic side elevational view of a mechanism embodying the persent invention;

FIG. 2 is a schematic view of an enlarged scale of a portion of the mechanism shown in FIG. 1;

FIG. 3 is a fragmentary cross-sectional view of the mechanism of FIG. 1, taken approximately on the section line 3-3 of FIG. 1;

FIG. 4 is a cross-sectional view of the mechanism shown in FIG. 2, taken approximately 0n the section line 44 of FIG. 2;

FIG. 5 is a cross-sectional view of the mechanism shown in FIG. 4, taken approximately along the section line 55 of FIG. 4;

FIG. 6 is a cross-sectional view of the mechanism shown in FIG. 4, taken approximately along the section line 66 of FIG. 4;

FIG. 7 is an elevational view of a portion of the mechanism shown in FIG. 3, looking at the mechanism of FIG. 3 as indicated by the line 7-7 thereof; and

FIG. 8 is a sectional viewof the mechanism shown in FIG. 3, taken approximately along the section line 8-3 of FIG. 3.

The present invention provides an improved sheet feeding mechanism for feeding sheets to a work station and is shown in the drawings as preferably embodied in a sheet feeding mechanism 10 for feeding sheets to a printing press 11. The sheet feeding mechanism 10 is of the type wherein the topmost sheet of a pile P is fed into the nip of a pair of advancing rolls 13 located forwardly of the pile and which feed the sheet down a feedboard 14 into the printing press 11. The pile is generally supported on a suitable hoist which raises the pile as sheets are fed therefrom, so that the top of the pile is always at substantially the same level.

The sheets are fed from the pile P by suitable suction sheet-separating and feeding means. The suction sheet separating and feeding means includes sheet-raising suckers 16 and sheet-forwarding suckers 17. The sheet-raising suckers 16 engage and grip the rear portion of the topmost sheet in the pile and move vertically to raise it from the next sheet on the pile and to the forwarding suckers 17. The forwarding suckers 17 grip the sheet raised by the suckers 1 6 and move the sheet forwardly toward the forwarding rolls 13 and move the forward or leading edge thereof into the nip of the rolls 13. The operating mechanism for the

suckers

16 and 17 will not be described in detail since any well-known operating mechanism may be utilized, and reference may be made to applicants copend application, Serial No. 332,596 for a specific showing of a particular type of mechanism for raising and lower-ing the suckers 16 and moving the forwarding suckers 17.

The sheet feeding mechanism 10 includes a means for directing a stream of separating air to the edges of the uppermost sheets in the pile to, as is well known, ruflle the edges of the sheets and assist in separating the topmost sheet from the stack. The means for directing the stream of separating air includes air nozzles 18 located adjacent opposite sides of the pile and positioned to direct the air against the rear edges of the uppermost sheets in the pile. The sheet feeding mechanism also includes means for directing a stream of floating or forwarding air between the topmost sheet of the pile and the next adjacent sheet in the pile toward the forward end thereof to assist in the separating of the topmost sheet from the pile and to facilitate moving the sheet forwardly. The floating air functions to provide a film of air between the topmost sheet and the pile to thereby separate or break the forward end of the topmost sheet from the next adjacent sheet so as to facilitate movement of the sheet forward by the forwarding suckers. The means for directing the floating air toward the forward end of the sheet comprises floating air nozzles 19 located to direct air under the topmost sheet in the pile and toward the forward end thereof.

The sheet floating air stream, the separating air stream, and the suction for

sucker members

16 and 17 are all controlled by a single rotary valve 20 which connects the floating air nozzles 19 and separating air nozzles 18 to an air supply line 21 and which connects the

sucker members

16 and 17 to a suction supply line 22 in timed relation with the operation of the sheet feeding mechanism. The particular construction of the rotary valve 20 forms no part of the present invention and will not be described in detail. It should suflice to say that the valve does include a valve member which is rotated in timed relation to the movement of the

sucker members

16 and 17 and upon rotation, controls the suction in the sucker members and the air flowing through the various nozzles describes hereinabove. A particular type of valve which might be utilized for this purpose is shown in copending application, Serial No. 290,841, filed June 26, 1963, now Patent No. 3,226,107.

The control of the magnitude of the suction and air pressure is quite important in the sheet feeding mechanism. The air pressure should not be applied to the

nozzles

18, 19 until suction of a degree suflicient to handle the sheets has been applied to the

sucker members

16 and 17. Moreover, the air pressure in the nozzles should be such as not to disarrange the sheets in the pile and to provide for effective feeding of the sheets. Generally, the air pressure should be adjusted depending upon the type of sheet stock being handled and the speed at which the sheets are being fed. The greater the speed of operation, the greater the air pressure should be.

Accordingly, the sheet feeding mechanism 10 includes a valve means 24 located in the air pressure line 21 and a valve means 26 located in the suction line 22. The

valves

24 and 26 have a common valve body 27 and are operable to control the magnitude of pressure and suction, respectively, in the lines in which they are located. The common valve body is secured in the frame of the mechanism by suitable screws 28. The valve 24 is adjustable in order to vary the air pressure in the line 21. Moreover, in accordance with the present invention, the valves are operated by an actuating means so as to effect full suction pressure at the

suckers

16 and 17 prior to any pressure being directed through the

nozzles

18 and 19, and then increase of the air pressure in the

nozzles

18, 19 without any increase in the suction applied to the

sucker members

16 and 17.

The valve 24 for controlling the air pressure in the air supply line 21 includes a valve body portion 30 forming a part of the common valve body 27. The body portion 30 has an inlet opening 31 and an outlet opening 32 which are connected by a bore 33 and through which air pressure in the supply line 21 is directed. The body portion 30 may have an outlet opening 34 communicating with the bore 33 and leading to other mechanism in order to provide air pressure thereto, if desired. Moreover, a suitable air pressure gauge 34a is located adjacent the valve 24 in the air pressure supply line 21.

The body portion 30 of the valve 24 also includes a plurality of ports 35 communicating with the atmosphere. The ports 35 also communicate with the bore 33 by a passageway 36 extending therebetween. As viewed in the drawings, the passageway 36 is blocked by a movable member 37 comprising a spherical ball member. The ball member 37 is movable from the position shown in FIG. 6 wherein it engages a seat 38 and blocks any flow of fluid through the passageway 36 to the ports 35 to a position out of engagement with the seat 38 at which air may flow through the passageway 36 through the vent ports 35.

The ball member 37 is biased by a spring 40 downwardly, as viewed in FIG. 6, into engagement with the valve seat 38 and, thus, is biased to a position wherein the ports 35 are blocked from communication with the bore 33. It can be seen, of course, that when the ball 37 is in position blocking communication between the ports 35 and the bore 33, air pressure flows through the valve inlet and outlet ports to the valve 20 which controls the flow of air to the

air nozzles

18, 19. Air pressure in the bore 33 acts on one side of the ball 37 and if sufficient to overcome the force of the spring 40, will move the ball 37 away from the seat 38 and, thereby, provide a leak of air pressure to the atmosphere through ports 35. Thus, the air pressure in the line 21 is reduced. Of course, if the bias of the spring 40 is greater than the air pressure, the ball 37 remains in engagement with the seat 38 and prevents leakage of air to the atmosphere and, therefore, provides maximum air pressure in the valve.

The air pressure in the air line 21 and

nozzles

18, 19, as should be apparent from the above, is a function of the bias on the spring 40 and as the bias on the spring 40 increases, the air pressure in the air line likewise increases. The bias on the spring 40 may be increased by movement of a plunger member 41 vertically in a bore 42 in the valve body portion 30. The plunger member 41 has a passageway or opening 43 therein in which one end portion of the spring 40 is positioned. The other end of the spring 40, of course, engages the surface of the ball member 37. The plunger member 41 is movable in a vertical direction in the bore 42 by means of a cam member 45 which engages the upper surface 41a of the plunger member 41 and the plunger member 41 is held in engagement with the surface of the cam 45 by the spring 40.

In the position shown in FIG. 6, the plunger 41 is in its uppermost position and the bias on the spring 40 is at its lowest. In this position, air pressure directed into the bore 33 causes the ball 37 to move away from the seat 38 and causes leakage of the air pressure to the atmosphere and provides zero air pressure in the valve 20. Upon movement of the cam 45 in a clockwise direction from the position shown in FIG. 6 for approximately degrees, no increase in the compression of the spring 40 is effected because the cam surface portion 46 which will have engaged the upper surface 41a of the plunger member 41 is a dwell surface. Further movement, however, of the cam member 45 will effect a lowering of the plunger member 41 causing compression of spring 40 and an increase in the biasing force of the spring 40 tending to hold the ball 37 in engagement with the seat 38. This causes a reduction in the leakage of air past the ball 37 and an increase in the air pressure in the bore 33 and valve 20. As the came member 45 is rotated, the amount of biasing force on the spring 40 is increased progressively so as to decrease the air leaking past the ball member 37 to the ports 35 leading to the atmosphere, thus progressively increasing the pressure in the bore 33 and, in turn, increasing the pressure in the valve 20 and

nozzles

18, 19.

The valve member 26 which is located in the suction line 22 is operable to control the amount of suction in the

suckers

16 and 17. The valve member 26 includes a valve body portion 50 forming a part of the common valve body 27 and having a suction inlet port 51 and a suction outlet port 52 which are in communication with each other through a chamber 53. A suitable passageway 54 also communicates with the chamber 53 and into which a relief valve member 55 may be positioned. The relief valve 55 is adjustable to determine the maximum suction pressure in the suction line. The valve 55 functions as a safeguard to prevent too great a suction build-up in the suction line. This valve is adjusted depending upon the pump and particular structure of the feeding mechanism 18. The valve body portion 50 also has an opening 54a in communication with the chamber 53 and which leads to a gauge 54b. The body portion 50 of the valve 26 also includes a plurality of ports 56 in communication with the atmosphere. The ports 56 also communicate with the chamber 53 and provide a release for the suction in the chamber 53 when in communication therewith.

The valve 26 further includes a means for blocking off the ports 56 from the chamber 53. This means comprises a plunger member 58 which is movable vertically, as viewed in FIG. 5, in a bore 59 in the valve body portion 50. The plunger 58 has a suitable opening 60 in the bottom portion thereof, as viewed in FIG. 5, into which one end of a coil spring 61 is positioned, the other end of the coil spring bears against a spring seat 62 formed on the valve body portion 58. The plunger member 58 is moved in the bore 59 by means of a cam member 61. The cam 61 upon movement in a clockwise direction causes vertical lowering movement of the plunger 58 from the position in which it is shown in FIG. 5. Upon initial movement of the cam 61 in a clockwise direction, as viewed in FIG. 5, the surface portion 62 thereof engages the upper surface portion 58a of the plunger 58 and causes the plunger 58 to be moved vertically downwardly. As the plunger 58 moves downwardly, a portion 58b thereof moves to block ports 56 from chamber 53 and the amount of communication between the chamber 53 and the vent ports 56 is reduced. After the cam 61 is moved through approximately 90 degrees of rotation, the ports 56 are completely blocked from chamber 53 thereby providing maximum suction in the chamber 53 which, in turn, provides maximum suction in the

sucker members

16 and 17. Further rotational movement of the cam 61 does not change the suction pressure in the chamber 53 for a dwell portion 62a of the cam engages the plunger 58. The dwell portion of the cam member 61 is provided with a plurality of indentations 64 which cooperate with surface 58a of the plunger 58 and tend to hold the cam 61 in the position to which it is rotated. The rotation of the cam 61 in the clockwise direction is limited by a stop means. The stop means comprises a pin 65 which projects outwardly of the cam 61 and engages a portion 66 of the body portion 50 when rotated to its limit in the clockwise direction.

The

cam members

45, 61 for actuating the

valves

24, 26

are part of a manually actuated operating means for operating these valves. The

cams

45 and 61 are mounted on a common control shaft 70. The control shaft 70 is rotatably supported by the common valve body at one end thereof and in the frame of the feeding mechanism. The

cams

45 and 61 are fixedly secured to shaft 70 and positioned on the shaft 70 so that when the cam 45 is in the position shown in FIG. 6, the cam 61 is in the position shown in FIG. 5. Thus, in this position of the earns, the air and suction pressures are at a minimum and preferably zero.

The shaft 70 extends transverse to the direction of movement of the sheets and to a position adjacent an operator's platform 75 which is positioned between the printing press 11 and the pile of sheets P. The shaft 70 has a control knob 76 fixedly secured on the end thereof adjacent to the platform 75 and which is readily accessible to an operator standing on the platform 75. An operator standing on the platform 75 therefore may rotate the knob 76 and, in turn, rotate the shaft 70 to control the air pressure and suction pressure. The controls for operating the printing press 11 and the feeder mechanism and to-control the speed thereof are also located so as to be accessible to the operator standing on the platform 75. Thus, an operator standing on the operators platform need not move from the platform 75 in order to adjust the air pressure in the

nozzles

18, 19 when the speed of the press is varied.

The air pressure and the suction applied to the

valves

24, 26 is created by a suitable pump means shown schematically in FIG. 1 and designated 80. The pump means 80 may comprise any suitable single type of pump mechanism for providing air and suction in the air and

suction lines

21 and 22, respectively, or may comprise separate pumps. The pump means 80 is shown as a single pump mechanism actuated to provide the suction and air pressure upon initial rotation of the shaft 70 from the position shown in the drawings. To this end, the shaft 70 carries a trip member 81. The trip member 81 comprises a cam or collar member rigidly secured to the shaft 70 for rotation therewith and has

flats

82 and 83 spaced therealong. The trip member 81 cooperates with a pair of switch members 84, mounted in the frame of the machine adjacent thereto to effect actuation of the 'pump means 80.

The switch means 84 is a normally open switch having a control member 86 which engages the periphery of the cam or trip member 81 and is actuated thereby. The switch 85 is a normally closed switch having a control member 87 which engages the periphery of the trip member 81 and is controlled thereby. The trip member 81 and the switches 84, 85 are shown in FIG. 8 in the position in which they occupy when the shaft 70 and the

cams

61 and 45 are in the position wherein minimum air and suction pressures are in the air and suction lines, respectively. In this position, the control member 86 of the normally open switch 84 is in engagement with the flat 82 on the periphery of the trip member 81. In this position, the switch 84 is in its normal position with its switch contacts open. The switch 85, however, is held out of its normal position by engagement of its control member 87 with the circular periphery of the trip member 81 and, thus, is open also.

When it is desired to apply suction and air pressure in the supply lines, the shaft 70 is rotated in a clockwise direction. Initial rotation of the trip member 81 clockwise, from the position shown in FIG. 8, causes the control member 86 for the switch 84 to ride off the fiat 82 and into engagement with the periphery of the cam member 81. This moves the control member 86 thereof to the right, as shown in FIG. 8, causing the contacts of the switch 84 to be closed. At substantially the same time, the control member 87 for the switch 85 moves into engagement with the flat 83 causing its switch contacts to take their normal position, namely, closed. In this position, with both switches closed, a circuit is completed through the contacts of the switches which are in series to a relay which establishes a holding circuit around the contacts of the switch 85 and, at the same time, energizes contacts in the circuit for the motor controlling the pump means 80. Further movement of the trip means in the clockwise direction causes the control member 87 for the switch 85 to ride off flat 83 and onto the periphery of the trip member. This causes the control member 87 to move to the right and opens contacts of the switch 85. The above-noted relay, however, remains energized, even though the switch 85 is returned to its open position, due to the holding circuit around the contacts of the switch 85.

When it is desired to decrease the air pressure in the

nozzles

18, 19, the shaft 78 is turned in a counterclockwise direction. Upon rotation of the shaft 70 in a counterclockwise direction, toward the position shown in FIG. 8, initially the circuit remains in a condition wherein the contacts of the switch 84 are closed, while the contacts of the switch 85 are open. However, the flat 83 permits the control member 87 of the switch 85 to move outwardly causing closing of the contacts thereof. This performs no function at this time since a circuit is still maintained through switch 84 and the holding contacts around the contacts for the switch 85. The flat 82 then comes into engagement with the control member 86 of the switch 84 causing the control member 86 to move to the left, as viewed in FIG. 8, causing the contacts of the switch 84 to open. This breaks the circuit to the relay which opens the contacts connected with the pump motor and the contacts of the holding circuit, thereby deenergizing the pump motor. The control circuit including the switches 84, 85 thus functions to prevent operation of the pump after a power cutoff, without returning the trip member 81 and switches to the condition that they have when in the position shown in FIG. 7.

As best seen in FIG. 7, the sheet feeding mechanism includes an indicator 90 secured to the shaft 70 for movement therewith and an indicator plate 91 secured to the frame of the machine. The indicator plate has a zero or off position in which it is located in FIG. 8. As the shaft 70 is rotated to turn on the pump means 80 and increase the suction, the indicator 90 moves to indicate suction increase on the plate 91. The plate 91 includes a plurality of numbers indicating different air pressures in the

nozzles

18, 19 and when the indicator points to a particular number, a corresponding pressureis applied to the

nozzles

18, 19.

From the above description, the operation of the preferred embodiment of the present invention should be apparent. With the structure in the position wherein the

cams

45 and 61 are in the position shown in FIGS. and 6, and the switches 84 and 85 are in the position shown in FIG. 8, the indicator 90 is in a position, shown in FIG. 7, wherein it indicates that the vacuum pressure is zero and the air pressure is zero. Rotation of the shaft 70 in a clockwise direction, as viewed in FIGS. 7 and 8, does not affect the air pressure due to the fact that the cam dwell surface portion 46 of the cam 45 will be running in engagement with plunger surface 41a of the valve 24. However, the suction is increased due to the fact that the portion 62 of increasing radius of the cam 61 forces the plunger 58 downwardly in the bore 59 of the valve 26. Once the vacuum is fully on, the air pressure is then progressively increased upon further rotation of the shaft 70 and may be incrementally increased nine steps, as indicated on the indicator plate 91, which cooperates with the indicator arrow 90. The pressure is increased due to the fact that the portion of increasing radius of the cam 45 now runs in engagement with the plunger 41 of the valve 24 and forces the plunger 41 of the valve 24 downwardly to increase the bias of the spring 40. Upon reverse rotation of the shaft 70 initially, of course, the pressure in the air line 21 is decreased to a point where it is reduced to a minimum, and then the pressure in the suction nozzles is decreased to the point where it is entirely off, and the cam members have been returned to the position shown in FIGS. 5 and 6, at which time the switches 84 and 85 are operated to de-energize the pump means 80.

From the above description, it should be apparent that applicant has provided a new and improved mechanism and that certain modifications, changes, and adaptations may be made therein by those skilled in the art to which it relates, and it is intended hereby to cover all such modifications, changes, and adaptations which fall within the scope of the appended claims.

What I claim is:

1. A sheet feeding mechanism for feeding sheet material from a pile comprising suction feed means for engaging the top sheet of the pile and feeding it forwardly thereof, nozzle means for directing a stream of air toward said sheet to assist in the feeding thereof, suction and air pressure supply lines leading from a source of suction and air pressure respectively to said suction feed means and said nozzle means respectively, first valve means in said suction supply line operable to control the pressure in said suction supply line, second valve means in said air supply line operable to vary the pressure in said air supply line, and actuating means for said first and second valve means effective to operate said first valve means to provide a predetermined suction pressure in said suction supply line and then subsequently operate said second valve means to apply air pressure to said air supply line of a progressively increasing magnitude including a single control member for operating said actuating means.

2. A sheet feeding mechanism for feeding sheet material from a pile to a sheet handling machine comprising suction sheet separating means for energizing the top sheet of the pile and feeding said sheet forwardly thereof, nozzle means for directing a stream of air toward said sheet to assist in the feeding thereof, suction and pressure supply lines leading from a source of suction and air pressure respectively to said suction feed means and said nozzle means respectively, an operators plat form adjacent said sheet handling machine and remote from said sheet separating means and on which the operator may stand and control the speed of operation of said separating means, first valve means in said suction supply line operable to control the pressure in the suction supply line, second valve means in the air supply line operable to vary the pressure in said air supply line, and actuating means for said first and second valve means effective to operate said first valve means to provide a predetermined suction in said supply line and then subsequently operate said second valve means to apply air pressure to said air supply line of a progressively increasing magnitude and including a single control member for operating said actuating means and accessible to an operator standing on said operators platform.

3. A sheet feeding mechanism for feeding sheet material from a pile to a sheet handling machine comprising suction sheet separating means for engaging the topmost sheet of the pile and feeding it forwardly thereof, nozzle means for directing a stream of air toward the sheet being fed to assist in the feeding thereof, pump means for creating a suction pressure and an air pressure, suction and pressure supply lines connected with said pump means for delivering suction and air pressure respectively to said suction sheet separating means and said nozzle means, an operators platform adjacent to said sheet handling machine and remote from said sheet separating means and from which an operator may control operation of said separating means, first valve means in the suction supply line operable to control the pressure in the suction supply line, second valve means in the air supply line operable to control the pressure in said air supply line, and actuating means for said first and second valve means elfective to operate said first valve means to provide a predetermined suction in said suction supply line and then operate said second valve means to apply air pressure to said air supply line of a progressively increasing magnitude and including a single control member movable to operate said actuating means and accessible to an operator on said platform, and means for energizing said pump means in response to initial movement of said control member.

4. A sheet feeding mechanism for feeding sheet material from a pile comprising suction feed means for engaging the topmost sheet of the pile and feeding it forwardly thereof, nozzle means for directing the stream of air toward the sheet being fed to assist in the feeding thereof, pump means forcreating a suction pressure and an air pressure, suction and pressure supply lines connected with said pump means for delivering suction and air pressure respectively to said suction feed means and said nozzle means, first valve means in the suction supply line operable to control the pressure in the suction supply line, second valve means in the air supply line operable to control the pressure in said air supply line, and actuating means for said first and second valve means effective to operate said first valve means to provide substantial suction in said suction supply line and then operate said second valve means to apply air pressure to said air supply line of a progressively increasing magnitude and including a single control member movable to operate said actuating means, and means for energizing said pump means in response to initial movement of said control member.

5. A sheet feeding mechanism for feeding sheet material from a pile comprisinr suction feed means for engaging the top sheet of the pile and feeding it forwardly thereof, nozzle means for directing a stream of air toward said sheet to assist in the feeding thereof, suction and air pressure supply lines leading from a source of suction and air pressure, respectively, to said suction feed means and said nozzle means respectively, first valve means in said suction supply line operable to vary the pressure therein, second valve means in said air supply line operable to vary the air pressure therein, said first and second valve means each including a control member movable to control the pressure in their respective lines, first and second cam members associated with each of said first and second valve means and-operatively connected with said control members respectively and operable upon movement to effect movement of said control members, and a shaft member carrying said first and second cam members and rotatable to effect rotation of said first and second cam members to move said control members of said first and second valve means, said first cam member having a cam surface operable to move said control member of said first valve to establish a suction of a predetermined degree in said suction feed means, and said second cam member having a cam surface operable to move said control member for said second valve to establish an air pressure in said nozzle means after suction is established in said suction feed means and with the air pressure progressively increasing upon continued movement of said control member.

6 A sheet feeding mechanism as defined in claim wherein said first cam member has an actuating surface portion for effecting movement of the control member for said first valve means to increase suction in said suction line and a dwell surface portion, and said second cam member has a dwell portion for engaging the control member for said second valve means while said actuating sur-. face portion of said first cam member engages the control member for said first valve means and an actuating portion for engaging the control member for said second valve means while said dwell portion of said first cam member engages the control member of said first valve means. I

7. A sheet feeding mechanism as defined in claim 5 wherein said first valve means comprises a valve body having suction inlet and suction outlet ports and at least one vent opening to the atmosphere and communicating with said suction inlet and outlet ports, said control member for said first valve means comprising a plunger means movable by said first cam member to block communication of said inlet and outlet ports with said vent port, and spring means applying a biasing force against said plunger means to hold said plunger means in engagement with said first cam member.

8. A sheet feeding mechanism as defined in claim 5 wherein said second valve means comprises a valve body having inlet and outlet ports and at least one vent port communicating With the atmosphere and with said inlet and outlet ports, said control member for said second valve means comprising a plunger member, a movable member for at least partially blocking communication between said inlet and outlet ports and said vent port, spring means acting between said plunger member and said movable member and biasing said plunger member into en- 10 gagement with said second cam member and said movable member into a position blocking communication between said inlet and outlet ports and said one vent port.

9. A sheet feeding mechanism for feeding sheet material from a pile comprising suction feed means for engaging the top sheet of the pile and feeding it forwardly thereof, nozzle means for directing a stream of air toward said sheet to assist in the feeding thereof, suction and air pressure supply lines leading from a source of suction and 'air pressure, respectively to said suction feed means and said nozzle means respectively, first valve means in said suction supply line operable to vary the pressure therein, second valve means in said air supply line operable to vary the air pressure therein, said first and second valve means each including a control member movable to control the pressure in said respective lines, first and second cam members associated with each of said first and second valve means and operatively connected with said control members respectively and operable upon movement to effect movement of said control members, a shaft member carrying said first and second cam members and rotatable to effect rotation of said first and second cam members to move the control members of said first and second valve means, pump means for creating said suction and air pressure, and means for energizing said pump means in response to rotation of said shaft member.

in). A sheet feeding mechanism as defined in claim 9 further including switch means actuatable to energize operation of said pump means and trip means carried by said shaft member and operable to energize said switch means to effect operation of said pump means upon initial rotation of said shaft member.

11. A sheet feeding mechanism for feeding sheet material from a pile comprising suction feed means for engaging the top sheet of the pile and feeding it forwardly thereof, nozzle means for directing a stream of air toward said sheet to assist in the feeding thereof, suction and air pressure supply lines leading from a source of suction and air pressure, respectively, to said suction feed means and said nozzle means, respectively, first valve means in said suction supply line operable to vary the air pressure therein, second valve means in said air supply line operable to vary the air pressure therein, said first and second valve means each including a control member movable to control the pressure in said respective lines, first and second actuating members associated with each of said first and second valve means and operatively connected with said control members respectively and operable upon movement to effect movement of said control members, said first actuating member being operable to move said control member of said first valve to establish a suction of a predetermined degree in said suction feed means, said second actuating member being operable to move said control member of said second valve to establish an air pressure in said nozzle means after suction is established in said suction feed means and with the air pressure progressively increasing upon continued movement of said control member by said actuating member, and a movable member carrying said first and second actuating members and movable to effect movement of said first and second actuating members to effect movement of said control members of said first and second valve means.

References Cited by the Examiner UNITED STATES PATENTS 1,587,816 6/1926 Broadmeyer 27127 1,716,948 6/ 1929 Broadmeyer 27127 2,046,728 7/ 1936 Dawson 27127 X 2,764,407 9/ 1956 Alix 271-26 2,874,962 2/1959 Layden 27127 2,973,610 3/1961 Randall 271-27 X M. HENSON WOOD, JR., Primary Examiner.

V. C. WILKS, Assistant Examiner.

Claims

1. A SHEET FEEDING MECHANISM FOR FEEDING SHEET MATERAIL FROM A PILE COMPRISING SUCTION FEED MEANS FOR ENGAGING THE TOP SHEET OF THE PILE AND FEEDING IT FORWARDLY THEREOF, NOZZLE MEANS FOR DIRECTING A STREAM OF AIR TOWARD SAID SHEET TO ASSIST IN THE FEEDING THEREOF, SUCTION AND AIR PRESSURE SUPPLY LINES LEADING FROM A SOURCE OF SUCTION AND AIR PRESSURE RESPECTIVELY TO SAID SUCTION FEED MEANS AND SAID NOZZLE MEANS RESPECTIVELY, FIRST VALVE MEANS IN SAID SUCTION SUPPLY LINE OPERABLE TO CONTROL THE PRESSURE IN SAID SUCTION SUPPLY LINE, SECOND VALVE MEANS IN SAID AIR SUPPLY LINE OPERABLE TO VARY THE PRESSURE IN SAID AIR SUPPLY LINE, AND ACTUATING MEANS FOR SAID FIRST SAID SECOND VALVE MEANS EFFECTIVE TO OPERABLE SAID FIRST VALVE MEANS TO PROVIDE A PREDETERMINED SUCTION PRESSURE IN