US3017796A - Intermittent web feed mechanism - Google Patents

Description

Jan. 23, 1962 F. G. AUER ETAL 3,017,796

INTERMITTENT WEB FED MECHANISM Filed June 26, 1957 4 Sheets-Sheet 1 Jan. 23, 1962 F. G. AUER ETAL 3,017,796

INTERMITTENT wEE FEED MECHANISM Filed June 26, 1957 4 Sheets-Sheet 2 Ekr Y .50

A men/frs.

Jan. 23, 1962 F. G. AUER ETAL 3,017,796

INTERMITTENT WEB FEED MECHANISM Filed June 26, 1957 4 Sheets-Sheet 3 Jan. 23, 1962 F. G. AUER ETAL 3,017,796

INTERMITTENT WEB FEED MECHANISM Filed June 26, 1957 4 Sheets-Sheet 4 //V VE /V 7" 0,95 FPEDF/Q/CK AUI@ MOP@ /5 .SOPA/// fr d ate

3,017,796 INTERMITTENT WEB FEED MECHANISM Frederick G. Auer, Teaneck, and Morris Sorkin, Bergeneld, NJ., assignors to Champlain Company, Inc., Bloomfield, Nal., a corporation of New York Filed lune 26, 1957, Ser. No. 668,224 8 Claims. (Cl. 825-263) This invention relates to intermittent web feed mechanism, and more particularly to what may be termed a hydraulic negative flywheel for use with such mechanism.

There are many processes in which it is necessary to feed a web continuously at one point, and intermittently at another point. A common example is the combination of a rotary printing press with a reciprocating press which scores, punches or cuts the printed web. For brevity the term punch is used hereinafter. The punch press works on an intermittently stationary web, which forms part of a uniformly moving web in the printing press. The problem is to secure accurate registration of the print and the cut, combined with high speed opera-tion.

Mechanism for such intermittent feed through a punch press is disclosed in U.S. Patent No. 2,658,406 entitled Variable Speed Feed Mechanism, granted November 10, 1953, to John Gibson Mcllvain, Ir. A different mechanism for the same purpose is disclosed in U.S. Patent No. 2,548,136, entitled Register Control Means for Continuous and Intermittent Web Feed Mechanism, granted April 10, 1951, to Frederick Auer.

It has proved difficult to obtain perfect cut-to-print register. It has been found that backlash is a major factor in causing cuttoprint variations, because of the intermittent drive, which repeatedly accelerates and decelerates. The error caused by this factor tends to grow worse as the parts of the mechanism become worn. lt has already been suggested to load the intermittent feed roller by means of a brake, thus keeping the backlash in one direction at all times. This is helpful, but is inefficient because of the substantial waste of power and excessive wear of the mechanism caused by the continuous application of braking force.

The primary object of the present invention is to generally improve intermittent feed mechanism of the specified character. A more particular object is to obtain the benefit of braking action, and to keep the backlash biased one way, but without waste of power. This is done by storing the braking energy lduring deceleration of the web, and reusing it during acceleration of the web. Differently expressed, the braking energy which helps slow the web to a stop is restored and used to help drive the web at a speed above normal speed to make up for the stop. Thus, the operation is opposite to that of a common flywheel, and the present mechanism may be thought of as a negative flywheel.

Accordingly, one object of the invention is to provide mechanism operating in proper phase with the intermittent feed of a web, to improve the accuracy of the feed, and the efficiency of the mechanism in its utilization of the power of the main driving motor.

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, our invention resides in the intermittent web feed mechanism, and the elements thereof, and their relation one to another, as are hereinafter more particularly described in the following specification. The specification is accompanied by drawings in which:

FIG. 1 is an elevation of part of our intermittent feed mechanism, to be used with a reciprocating press;

FiG. 2 is a partially sectioned elevation looking in the direction of the arrows 2 2 of FIG. 1;

FIG. 3 is a schematic flow diagram, showing the operation during acceleration of the web;

FIG. 3a is a graph explanatory of FIG. 3;

FIG. 4 is a diagram showing the pressure relations dur-rl ing movement of the web at constant velocity;

FIG. 4a is a graph explanatory of FIG. 4;

FIG. 5 is a flow diagram showing the operation just prior to deceleration;

FIG. 5a is a graph explanatory of FIG. 5;

FIG. 6 is a flow diagram showing the operation during deceleration;

FIG. 6a is a graph explanatory of FIG. 6;

FIG. '7 is a diagram explanatory of a typical installation of printing and punch press machinery, to which the invention is applicable; and

FIG. 7a is a graph explanatory of FIG. 7.

Referring to the drawing, and more particularly to FIG. 7, the entire line of machinery may be driven by a main drive shaft l2, which extends lengthwise of the moving web. Shaft l2 may be driven in any desired fashion, as by means of a main driving motor 14, operating through appropriate belts, chains or gearing indicated at 16.

The web 20 may be acted on by a series of multicolor printing units, which may be of the gravure type. The 4last two of a series of such units are here shown, there being a gravure cylinder 22 driven by main shaft 12 through gearing indicated at 24, and another gravure cylinder 26 driven by main shaft 12 through gearing indicated at 28. The printing units may be conventional, and may include the usual driers at 23 and 27 to dry the web between successive printing operations. Elaborato mechanism, including electric eye scanners 30, may be provided between successive printing units to maintain the different colors in registration, and for this purpose, the gearing symbolized at 24 and 28 may include appropriate running registers, preferably of the planatory or differential gear type, which permit the automatic feed of a slight positive or negative motion from correction motors to maintain registration. Scanning mechanism for this purpose may be of the type shown in U.S. Patent 2,348,862, entitled Register Control Apparatu issued to Morris Sorkin on May 16, 1944. Running register mechanism is shown in U.S. Patent 2,163,035, entitled Apparatus for Eifecting Register of Multiple Operations, issued .lune 20, 1939, to William F. Grupe.

The printed web is fed to a punch press 32 by means of an intermittent feed roller 34, cooperating as usual with an idler 36. The press 32 is driven by main shaft 12 through appropriate gearing at 38 and 40, connected at 42, and serving to reciprocate the punch, as by means of connecting rods 44 leading to eccentrics on punch press shaft 46. The intermittent feed roller 34 is also driven from main shaft 12, as by means of gearing in box 48 and box 50, the latter including appropriate cam or like mechanism to convert the continuous uniform speed rotation of shaft 12 to an intermittent rotation of roller 34. This mechanism may be of any suitable type, including either the Mcllvain drive shown in Patent 2,658,406, or the Auer drive shown in Patent 2,548,136, previously mentioned.

The intermittent drive preferably produces a web movement of the character shown graphically in FIG. 7a of the drawing. This shows web velocity as a function of angular rotation for one cycle. The average web speed at the printing cylinders 22 and 26 is indicated by the broken line 52. The web speed produced by the feed roller varies between a high velocity shown at S4, and a dwell or Zero velocity shown at 56. The reciprocating punch engages the web during the dwell period at 56.

The deceleration of the web from maximum to zero velocity is shown at 58. The acceleration of the web from zero to maximum velocity is shown at 60. Of course, the cycle used in any particular intermittent feed mechanism may vary, but in all cases, it is essential to have a dwell or zero velocity period during which a reciprocating press may operate on the web, and it is necessary to accelerate to a high velocity to make up for the dwell period. It is necessary to decelerate in order to provide the dwell period. The symmetrical curve shown in FIG. 7a is a simple and desirable way to achieve the intended purpose, but it is not essential that the deceleration and acceleration be linear, as shown, nor that they be at the same rate, nor is it essential to have a period of uniform high velocity, as shown at 54. That is desired in order to lessen the needed maximum velocity to obtain the required average velocity 52.

Regardless of the particular nature of the intermittent feed mechanism, it is evident that because of the alternating acceleration and deceleration, any backlash or play in all of the parts of the mechanism will introduce some uncertainty or inaccuracy in the feed. Many things have been done in an effort to improve the cut-to-print registration. For example, reverting to FIG. 7, the app 1- ratus includes a web pull unit using a pull roller 62 which is driven from the main drive shaft 12 through a gear box 64. Pull roller 62 cooperates with an idler 66. A slack loop of web is provided at 68 between the uniform velocity pull roller 62 and the intermittent feed roller 34. During each cycle this loop grows, say to the dotted line position 68', during dwell at roller 34, and then the loop is taken up and reduced to minimum dimension, as shown in broken lines at 68. This position of the loop may be determined by a xed cylinder '70. The gear ratio in the drive 4S leading to intermittent feed roller 34 is preferably so selected that the web is momentarily pulled tight once during each cycle. At that time, tension builds up between the intermittent feed roller 34 and the pull cylinder 62, as determined by the position of the stop cylinder 70, and the web then slips at the intermittent feed roller 34. As the intermittent feed roller 34 decelerates, and its peripheral speed approaches the speed of the web feeding out of the pull roller 62, the slipping stops and the web coming out of the feed roller 34 is controlled by that roller.

To correct or maintain the register, a compensator roller 72 may be interposed between the last printing unit 26 and the pull roller 62. The vertical position of compensator 72 may be controlled by a correction motor 74, driving vertical screws 76 which raise or lower the compensator 72. This may be under control of a web scanner 78 located near the pull roller 62, and cooperating with a suitable phase detector mounted on or geared to the main drive shaft 12. The phase detector may be of the type described in said Sorkin Patent 2,348,862.

The pull roller 62 is normally so selected that its peripheral speed very slightly exceeds that of the printing cylinder 26, and therefore the web is under tension therebetween. For perfect cut-to-print register, the position of a target printed on the web should remain in a fixed phase relationship with the printing cylinders as the web passes the pull roller 62. lf a slack loop is brought to a stop, as shown at 70, the print should be in fixed phase relationship to the printing press cylinder 26 at the instant that the web stops slipping at the intermmittent feed roller 34.

For perfect cut-to-print register, it would also be necessary for the web to travel precisely the same distance during each cycle from that instant until it is stopped under the die. The various gear boxes, such as 48 and 64 usually include change gears to accommodate changes in the length of the sheet or print, so that it will not be necessary to change the rollers 34 and 62 for each different print length. There is lost motion in all such gearing. The backlash in the intermittent drive mechanism also contributes to cut-to-print variation. Loading the intermittent feed roller 34 by means of a brake is helpful, but

obviously is ineicient and wasteful of power, and hastens wear of the mechanism.

In the present improvement, the backlash is removed during that portion of the cycle when it would be irnportant, without, however, imposing any additional load on the intermittent drive during the rest of the cycle, and indeed, energy is stored and then fed back to the intermittent roller, thereby greatly reducing the required power.

Referring now to FIGS. l and 2 of the drawing, the intermittent feed roller is shown at 34. The web moves from right to left, and the punch (not shown) follows roller 34. The .apparatus also includes the roller 80, which is merely a guide roller (as in FiG. 7), and the invention is applied to the intermittent feed roller 34. The web 2G is squeezed thereagainst by the usual idle roller 36. The main drive shaft, or another shaft which turns with uniform velocity in synchronism with the main drive shaft, is shown at 12, but the intermittent drive gearing which actually drives the roller 34 has been omitted in the drawing, as though on the opposite side of the apparatus.

The negative iiywheel action is obtained hydraulically, and for this purpose a fluid motor or hydraulic unit 82 (FIG. 2) is used. This acts as a motor when supplied with pressure fluid, and it acts as a pump when it is mechanically driven. It is geared to the feed roller 34 (FIG. l), as by means of a gear 84 meshing with idler 86, which in turn meshes with a pinion 8S on the fluid motor shaft. There is an accumulator (FIG. 2), and this preferably takes the form of a cylinder in which a piston is moved by a piston rod 92 under pressure of a powerful compression spring 94. The apparatus further includes valve mechanism, generally designated 96, which so connects the hydraulic unit 82 to the accumulator 9i) as to act either as a pump or as a motor. The Valve 96 is operated at appropriate times by means driven by the drive shaft 12. In the present case, shaft 12 (FIG. 2) drives a cam 100 through gears 102 and 104, and a cam roller 106 controls the valve 96. The timing of the parts is so set that the hydraulic unit 32 acts as a brake during deceleration, and acts as a motor during acceleration. The said motor then utiizes energy which was earlier stored up in the accumulator 90 when the parts were acting as a brake.

The complete apparatus includes some additional parts not shown in FIGS. l and 2, but which may be described with reference to the ow diagram shown in FIG. 3. In that figure, the intermittent feed roller is shown at 34, and it is geared to hydraulic unit 82 by gearing 84, 8S. The cam operated valve mechanism is shown at 96, 166, 100. The accumulator is shown at 90, and includes a piston under pressure of compression spring 94. The main drive shaft is indicated at 12, and drives the cam 100 through gearing 102, 104. The change gear box and the intermittent drive gear box for the feed roller 34 are shown schematically at 48 and 50. These parts all correspond to those already described.

However, in FIG. 3, attention may be called to a fluid reservoir 110, air breather 111, a relief valve 112, manually adjustable at 114, and two check valves 116 and 118, which open in the direction indicated by the arrows thereon. The reservoir supplies liquid to unit 82 when it acts as a pump to force liquid into accumulator 90, and the reservoir receives liquid from unit 82 when the latter acts as a motor driven by liquid expelled from the accumulator 90. The pressure relief valve 112 controls the maximum pressure that can be applied to the accumulator, and conversely, the maximum torque developed by the unit 32 when it acts as a motor. The check valve 116 permits free circulation or idling, as for example, if the liquid (usually oil) from accumulator 90 is exhausted before deceleration begins. Check valve 113 prevents the building up of excessively high pressure during a transition period when the valve 96 is changing, when all of the valve ports are closed.

A graph showing web velocity as a function of angular rotation for a cycle, is indicated in FIG. 3a, and the heavy portion marked 120 corresponds to the flow conditions illustrated in FIG. 3. This is the acceleration period during which hydraulic unit 82 acts as a motor to help accelerate the feed roller 34. Oil under high pressure is indicated in FIG. 3 by a heavy black line. Oil under low pressure is indicated by a heavy broken (dash-dash) line. The pipes shown by the double lines are idle. It will be evident that the valve 96, which may be a conventional four-way valve, has connected the accumulator 90 through pipes 122, 124, valve passage 126, and pipes 128, 130, to inlet port 132 of unit 82, and has connected the outlet port 134 through pipe 136, relief valve 112, pipe 138, valve passage 1411, and pipes 142 and 144, to the reservoir 110. Thus, the energy stored in the accumulator is now returned to the feed roller 34, minus only losses due to friction, which are readily kept below ten percent.

FIG. 4 shows the ow relationships during that part of the cycle indicated by the heavy line 146 in FIG. 4a, that is, during the uniform maximum velocity travel of the web. The stored oil is finally exhausted from the accumulator 90, and the hydraulic unit S2 simply circulates oil idly. The heavy broken line indicates low pressure, while the dotted line indicates that there is no pressure at all. More specifically, oil is discharged at outlet 134, and flows through pipe 136, relief valve 112, pipe 13S, valve passage 140, pipes 142, 143, check valve 116, and pipe 130, back to inlet 132. The unit S2 acts as a pump, but is working against no back pressure beyond pipe friction and the check valve 116, and thus the amount of energy absorbed by the pump is minor.

Referring now to FIG. 5, this shows the oW relationships at the part of the cycle indicated at 150 in FIG. 5a, that is, just ahead of deceleration of the web. This is a changeover point in valve 96, at which time the ports are ail momentarily blocked. In the present case this is 22 ahead of deceleration. At this time, pressure immediately starts to build up in accumulator 90. More specifically, oil owing from outlet 134 of hydraulic unit 82 ows through pipe 136, relief valve 112, pipe 152, check valve 118, pipes 154 and 122, into accumulator 91). In effect, the pipes 152 and 154 with the check valve 118, constitute a bypass around the four-way valve 96 when the ports are blocked. In similar fashion, oil is supplied to the pump from the reservoir 110 through pipes 144, 148, check valve 116 and pipe 130. Here again, the dotted line represents absence of pressure, and the heavy broken line represents low pressure, which of course soon (as in FIG. 6) becomes high pressure. It is indicated as low pressure because FIG. applies to only a brief instant of changeover when pressure first begins to build up.

FIG. 6 shows the relationship of pressures in the piping during the deceleration part of the cycle indicated at 156 in FIG. 6a. At this time, the four-way valve 96 has been changed to connect the inlet 132 of hydraulic unit 82 to the reservoir 110, and to connect the outlet 134 to the accumulator 90. Specifically, oil flows from reservoir 110 through pipes 144, 142 through valve 96 to pipes 128 and 131), and thence to pump inlet 132. Oil is discharged under pressure from outlet 134 through pipe 136, relief valve 112, pipe 138, through the four-Way valve 96, and thence through pipes 124 and 122 to accumulator 91B, where it compresses the spring 94, and so stores the braking energy, for utilization later, as described in connection with FIGS. 3 and 3a, during acceleration of the web after the reciprocating press (32 in FIG. 7) has operated on the web. Because of the Operation of the spring in accumulator 90, the braking unit 82 exerts an increasing torque against the feed roller and its drive, and thisitorque reaches its maximum value at the end of the deceleration portion of the cycle, and is maintained while the feed roller is at rest, and until the valve shifts, as shown in FIG. 3, whereupon the entire cycle repeats. The force exerted by spring 94 varies inversely as its length, and thus the braking and accelerating forces are variable, and are a maximum as the web cornes to dwell, and as acceleration begins, which is desirable.

The pressure relief valve 112 may be adjusted to limit the maximum pressure which can be built up. This is desirable because with fixed gearing between the intermittent feed roller and the hydraulic unit 82, the total rotation of the hydraulic unit depends on the diameter of the printing cylinders 22 and 26 in FIG. 7. In the present case, there is a step up gear ratio of four-to-one between the feed roller 34 and the hydraulic unit 82. When the print size is changed, the gravure cylinders are changed at 26 and 22 (FIG. 7), but the intermittent feed roller 34 is not changed, and instead, the gearing leading from the main drive shaft is changed to obtain the desired linear distance or feed of the web. This change in rotation of the feed roller is accompanied by a change in rotation of the hydraulic unit 82, which in turn may change the pressure build up, but the pressure may be readjusted to any desired limit bythe pressure relief valve 112.

It will be evident that change gears may be introduced between the feed roller and the hydraulic unit to accom- Dlish the same thing. Referring to FIG. l, the idler gear 86 is mounted on an arm 160 adjustable at 162, thus making it possible to change the diameter of gear 88, and the parts could be dimensioned for a much wider change in ratio than is here shown.

It is believed that the construction and operation, as well as the advantages of our improved intermittent feed mechanism, will be `apparent from the foregoing detailed description. The basic principle of the lapparatus is to eliminate the effect of backlash in the mechanism driving the intermittent feed rolle-r. A hydraulic unit driven by the feed roller develops back pressure, and puts a braking load on the feed roller du-ring the deceleration cycle, thus lstressing the driving mechanism. The high pressure in the spring loaded accumulator holds the feed roller in a stressed condition, even during the dwell period in the cycle of the punch. At the beginning of the acceleration cycle, the driving mechanism of the intermittent feed roller is inherently in a stressed condition, and this is true even though its load may be partly lessened by the energy stored in the accumulator. The four-way valve is controlled by a cam having a one-to-one turns ratio with the reciprocating press, and the valve reverses the fluid tiow and makes the hydraulic unit act as a motor, thus assisting the feed roller to accelerate from zero velocity to maximum velocity. This returns the energy stored up during deceleration.

One may say that the hydraulic mechanism provides a negative flywheel which helps produce a desired nonuniform velocity.

In FIG. 7 of fthe drawing, the parts are shown only schematically, and not at all to scale. In actual apparatus the intermittent feed roller 34 is located as closely as possible to the press 32, and the guide roller is close to roller 34, as is shown in FIG. 1. The parts associated with the electric eye 78 are kept close to rollers 80 and 34, and the web portions leading to and from compensator roller 72 are preferably parallel. These elements have all been spread apart for greater clarity of the drawing.

It will be understood that while we have shown and described our invention in a preferred form, changes may be made in the structure shown without departing from the scope of the invention as sought to be found in the following claims.

We claim:

1. Variable braking mechanism for use with intermittent Web feed apparatus operating in rapidly repeated feed cycles and comprising a uniform velocity drive shaft, an intermittent feed roller, and intermittent feed mechanism between said shaft and said roller, said variable braking mechanism comprising means driven by said feed roller to store up energy during deceleration of said feed roller in each cycle, and means to utilize the stored-up energy to help rotate said feed roller during acceleration of said feed roller in each cycle.

2. Apparatus for use with an intermittent web feed mechanism operating in rapidly lrepeated feed cycles, said web feed mechanism including a feed roller, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roller to rotate the latter intermittently in a cycle which includes acceleration, deceleration and dwell, said apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said unit to said feed roller, an accumulator, valve mechanism for so connecting said hydraulic unit to said accumulator as to act either as a pump or as a motor, and means driven by said drive shaft to shift said valve mechanism at appropriate times to cause said hydraulic unit to act as a brake during deceleration, and to act as a motor during acceleration, said motor utilizing energy which was earlier stored in said accumulator when said unit was acting as a brake. 3. Apparatus for use with an intermittent web feed mechanism operating in rapidly repeated feed cycles, said web feed mechanism including a feed roll, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roll to rotate the latter intermittently in a cycle which includes acceleration, uniform velocity, deceleration and dwell, said apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said uni-t to said feed roll, an accumulator, valve mechanism for so connecting said hydraulic unit to said accumulator as to act either as a pump or as a motor or for idle circulation, and means driven by said drive shaft to shift said valve mechanism at appropriate times to cause said hydraulic unit to act as a brake during deceleration, to act as a motor during acceleration, and to idly circulate liquid during uniform velocity drive of said feed roll, said motor utilizing energy which was earlier stored in said accumulator when said unit was acting as a brake.

4. Apparatus for use with a reciprocating press having an intermittent web feed mechanism operating in rapidly repeated feed cycles, said web feed mechanism including a feed roll, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roll to rotate the latter intermittently in a cycle which includes acceleration, deceleration and dwell, said apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said unit to said feed roll, an accumulator having a spring pressed piston and a cylinder, a reservoir, a four-way valve, a earn driven by said drive shaft in synchronism with the press to operate said valve to connect said hydraulic unit to pump liquid from said reservoir to said accumulator during deceleration, and to connect said hydraulic unit to act as a motor driven by liquid flowing from said accumulator to said reservoir during acceleration.

5. Apparatus for use with a reciprocating press having an intermittent web feed mechanism operating in rapidly repeated feed cycles, said web feed mechanism including a feed roll, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roll to rotate the latter intermittently in a cycle which includes acceleration, uniform velocity, deceleration and dwell, said `apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said unit to said feed roll, an accumulator having a spring pressed piston and a cylinder, -a reservoir, a fourway valve including ports, a cam driven by said drive shaft in synchronism with the press to operate said valve to connect said hydraulic unit to pump liquid from said reservoir to said accumulator during deceleration, and to connect said hydraulic unit to act as a motor driven by liquid flowing from said accumulator to said reservoir during acceleration, a check valve bypassing said fourway valve for ow from the pump outlet to said accumulator when the valve por-ts are blocked against such ilow, and another check valve bypassing said four-way valve for ow from said reservoir to the pump inlet when the valve ports are blocked against such flow.

6. Apparatus for use with a reciprocating press having an intermittent web feed mechanism operating in rapidly repeated feed cycles, said web feed mechanism including .a feed roll, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roll to rotate the latter intermittently in a cycle which includes acceleration, uniform velocity, deceleration and dwell, said `apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said unit to said feed roll, an accumulator having a spring pressed piston and a cylinder, a reservoir, a four-way valve, a cam driven by said drive shaft in synchronism with the press to operate said valve to connect said hydraulic unit to pump liquid from said reservoir to said accumulator during deceleration, and to connect said hydraulic unit to act as a motor driven by liquid owing from said accumulator to said reservoir during acceleration, and an adjustable pressure relief valve between the pump outlet and said accumulator.

7. Apparatus for use with a reciprocating press having an intermittent web feed mechanism operating in rapidly repeated feed cycles, said web feed mechanism including a feed roll, a drive shaft which rotates at uniform velocity, and mechanism between said drive shaft and said feed roll to rotate the latter intermittently in -a cycle which includes acceleration, uniform velocity, deceleration and dwell, said apparatus comprising a hydraulic unit adapted to act as a driving motor or as a driven pump, means gearing said unit to said feed roll, an accumulator having a spring pressed piston and a cylinder, a reservoir, `a four-way valve including ports, a cam driven by said drive shaft in synchronism with the press to operate said valve to connect said hydraulic unit to pump liquid from said reservoir to said accumulator during deceleration, and to connect said hydraulic unit to act as a motor driven by liquid owing from said accumulator to said reservoir during acceleration, a check valve by passing said four-way valve for ow from the pump outV let to said accumulator when the valve ports are blocked against such ilow, and another check valve by-passing said four-way valve for flow from said reservoir to the pump inlet when said Valve ports are blocked against such ow, and an adjustable pressure relief valve between said pump outlet and said accumulator.

8. In the operation of intermittent web feed mechanism driven in rapidly repeated feed cycles by a uniform velocity drive shaft, the method which includes driving the intermittent web feed mechanism by means of the uniform velocity drive shaft with periods of deceleration and acceleration in each feed cycle, and thereby feeding the web intermittently, storing energy and thereby braking the output of said intermittent feed mechanism during deceleration in each feed cycle, and supplying the said stored up energy to said intermittent feed mechanism in order to help drive said feed mechanism during acceleration of the web in each feed cycle.

References Cited in the le of this patent UNITED STATES PATENTS 2,489,411 Harrington Nov. 29, 1949 2,667,924 Dutro Feb. 2, 1954 2,693,235 Kenworthy et al. Nov. 2, 1954 2,758,837 Littell et al. Aug. 14, 1956 2,819,072 Wittek Jan. 7, 1958 2,839,138 Wilhelm June 17, 1958

Images