US2847208A - Inertia compensating device for printing press with reciprocating type bed - Google Patents

Description

Aug. 12, 1958 A. BUTTNER 2,347,208

INERTIA COMPENSATING DEVICE FOR PRINTING PRESS WITH RECIPROCATING TYPE BED 2 Sheets-Sheet 1 Filed NOV. 21. 1955 Z @7 [Li 2/ 6 2,847,208 PRINTING PRESS E BED 1958 A. BUTTNER INERTIA CQMPENSATING DEVICE FOR WITH RECIPROCATING TYP Filed Nov. 2-1, 1955 2 Sheets-Sheet 2 FIG. 6.

United States Patent INERTIA "COWENSATING DEVICE FOR PRINT- 'ING PRESS WITH RECIPR-O'CATING BED.

Artur Biittner, Heidelberg, Germany, assignor to Schnellpressenfahrik Aktiengesellschaft. Heidelberg, Heidelberg, Germany, a corporation of Germany Application November 21, 1955, Serial. No. 548,208,

Claims priority, application Germany-December 4, 1-954 5 Claims. (Cl..267-.,75)

This invention relates to apparatus for compensating the force of inertia of the reciprocating: type bed of a cylinder press.

During the reciprocating movement of the type bed of a cylinder printing press, there arise considerable forces of inertia which increase with increase of the operating speed. In order to compensate these forces of inertia, there have hitherto preferably been used air buffers by means of which the forces generated by the movements ofthe type bed were .absorbed at the reversing points of the movement thereof, and the energy thus stored used for assisting the reverse movement. In these prior arrangements of such air buffers, the buffer pistons and connectingrods-one of two at each end of the type bedare connected directly or by means of'pedestal bearings with the type bed itself, while the buffer cylinders associated therewith are anchored firmly to the machine frame. Thus the buffer pistons andconnecing rods participate in the type bed movement and hence increase the moving mass. Moreover, as the buffer pistons continuously. slide in and out of the cylinders, the flexible cup sleeves, which are used in most cases, are not troublefree in operation without constant attention.

Due to these faults in air buffer arrangements, attempts have been made to dimension the type bed gearings so that the forces of inertia may be absorbed without the use of air buffers. Such steps, however, are contrary to the aim of further increasing the output; of a cylinder press.

The length of the buffer cylinders, incidentally, has allowed them to be used only with those types of mechanical press in which the type bed, after covering a certain distance at a uniform speed, is slowed down to a standstill and is subsequently accelerated again. Withnonuniform type bed movements, i. e. sinusoidal or approximately sinusoidal movements, for example in stop-cylinder presses, it was not possible to use air buffers, although considerable forces of inertia arise with these kinds ofmovements.

The compensation of energy previously proposed for stop-cylinder presses by means of a tension spring, allows only an insufficient compensationofthe force of inertia owing to the impossibility of dimensioning the springs.

to do the job adequately.

In order to rem-ovethese disadvantages in compensating the forces of inertia of the reciprocatedtype bedbymeans of air compression, it is proposed in the presentinvention, to couple an air cushion herein termed an, air compressor,

preferably a rotary compressor, with the drive of the type bed, whereby the oscillating piston or vane: of, the compressor is driven by a shaft rotating, in, alternate directions.

The oscillating piston or vane of the compressor; .01

2,847,268 Patented Aug. 12, 1958 sections wherein no compression takes place. The oscillating vane may for this purpose, swing in aclosed housing, in which there, is disposed an intermediate distance piece or cross piece comprising a partition wall, so that theoscillating vane may swingto and fro from one side of the partition wall to the other, whereby the air enclosed between the vane and the partition wall is alternately compressed and expanded. Thus there results a simple and uninterrupted compensation of the inertia forces .occurring during the slowing down and acceleration of the type bed. The type bed is free of additional weight, by which there is attained a reduction of the forces of inertia to be compensated. Depending upon the position of the slots for the air intake into the housing,

. it is possible to select the compression pressures to conform approximately to the force curves of the type bed movement.

The apparatus proposed by the invention is suitable for stop and swinging cylinder machines, and also for single and two revolution machines. By suitably arranging the ports inthe casing of the enclosed compressor, it is possible to adapt the compression curve to allthe types of movements which are employed. The compensation of the inertiaforces not only causes a reduction of wear of the driving members, but it is also possible consequently to attain increased printing outputs with machines of given dimensions.

Ayfurther advantage over the know buffer arrangements consists in that theback pressure occurring during the compression strokes is transmitted to'the machine frame in :an opposite direction to the force of inertia of the type bed. The stability of the machine is thusconsiderably improved without fastening it to the floor.-

The invention will be described'further, by way of example, with reference .to the accompanying drawings, in which:

Fig. l isa sectional side elevation of a part of mechanical press having an inertia compensating apparatus constructed in accordance with the invention,

Fig. 2 is a cross-section of the press taken on the line Fig. 1,

Fig. 3 is a section taken on the line BB of Fig. 2, for a cylinder press-having a uniformly moved type bed andashort reversing movement, i. e. for single and two revolution machines,

Fig. 4 is an operating diagram showing the variations of the force of inertia occurring during one cycle of 360 and the compression curve with the, cylinder housing constructed according to Fig. 3,

Fig. 5 is a view similar to that of Fig. 3, but for a cylinder press having a non-uniform, i. e. sinusoidal or approximately sinusoidically moved type bed motion, as with stop and swinging cylinder mechanical presses.

Fig. 6 is an operating diagram for a stop or swinging cylinder mechanical press with the cylinder housing constructedaccording to Fig. 5.

Referring first-1y to Fig. l and 2', on the underside of a type bed 1, which carries a form 2, there-is fixed a rack bar 3 which engages with a gear wheel 4. During alternating rotation of the gear wheel4, for example, through angular displacement X, the type bed 1 is reciprocated in known manner alonga straight line, running on several rollers 6 which are guided in corresponding tracks of the machine frame 5. The flat form 2 moves underneath inking rollers '7 of the inking mechanism, whereby the fiat form 2 is inked, and subsequently the printing of the sheet'by means of the printing cylinder 3 is effected when the type bed passes underneath it. The known arrangements of mechanical presses such as the type bed drive, printing cylinder, inking mechanism and so forth are not particularly illustrated in the drawings, since they are .well known and do not form a part of the invention. The gear wheel 4, which effects the reciprocation of the type bed, is mounted on a shaft 9 which in turn is rotatably supported in known manner in the frame 5. The gearing for the alternating rotation of the shaft 9 is not shown and may likewise be of known construction.

For purposes of the present invention, the end of the shaft 9 supports a vane 11 which is additionally supported by a ring 10, the latter also being rigidly connected with the shaft 9. The van 11 thus also rotates through the angle X in a cylindrical housing or casing 12 which is screwed to the machine frame 5. Screwed firmly in the housing 12 there is a distance piece 13, which may also be termed a cross piece. The ring 10, on rotation of the shaft 9, rotates in a curved recess of the distance piece 13. Mounted on the housing 12 are poppet valves 14, which are guided in an insertable bearing member 15 anchored to the housing. Counteracting the weight of the poppet valve 14 is a compression spring 16, which is supported against an abutment 17 fixed on the bearing member 15. An adjustable compression spring 16 tends to maintain the valve plate in an upward position until an adjustable stop ring 18 bears on the abutment 17. Fig. 1 shows the left-hand valve in section, while the right-hand valve is shown in elevation.

Depending on the kind of movement, which the type bed undergoes, there are provided in the housing 12, ports 19 and 20 (Fig. 3) or 21 (Fig. The housing 12 is closed by means of an end cover 22 (Fig. 2).

The method of operation of the apparatus for compensating the force of inertia is as follows:

On alternating rotation of the shaft 9 for producing the reciprocating movement of the type bed, the vane 11, which is connected with the shaft 9, is moved in the housing 12 in a circular path. Thus, each time the vane passes the air slots 19, 20 (Fig. 3) or 21 (Fig. 5), the enclosed air is compressed to several atmospheres. Due to this compression of the enclosed air, the type bed movement is additionally delayed, while after passing the dead center position, the air expanding again with the rotary movement in the opposite direction, assists the acceleration of the type bed by means of the release of the stored energy during the expansion stroke.

The compensation of the force of inertia is effected,

depending upon the kind of type bed movement in such a manner that according to Figs. 4 and 6 the acceleration and delaying pressures which arise are completely or approximately balanced by the compression pressure.

When the cylinder housing is constructed according to Fig. 3 with ports 19 and 21), there are created three chambers in the casing, namely a neutral chamber a, and two compression chambers b and c.

With the construction according to Fig. 5 having only port 21 in the housing 12, the neutral chamber is omitted and there are only the two compression chambers e and 7.

Depending on the construction of the housing 12, as shown by the operating diagrams according to Figs. 4 and 6, it is possible to compensate extensively the force of inertia of any kind of type bed movement.

In the operating diagrams of Figs. 4 and 6, the forces of inertia occurring in one cycle, through 360, are denoted by P and P, While the area of the diagram bounded by the compression curve is shaded and denoted by J.

The force generated by the pressure rise while compressing the enclosed air are transmitted by the distance piece or cross piece 13 to the housing and thus on on to the machine frame. This back pressure acting on the vane 11 acts in an opposite direction to the movement of the type bed, which considerably improves the stability of the machine on the floor, and renders unnecessary floor fastenings otherwise required with high operational speeds.

With drives in which the shaft for transmitting the reciprocating type bed movement executes nearly a complete revolution or more, a reduction gear is incorporated,

so that the rotary piston or vane executes no more that about three quarters of a revolution.

In order to adapt the compression pressures to thz various operational speeds or the resultant forces of inertia respectively, known arrangements may be used tc cause a variation of the compression chamber or of the air supply to be compressed.

Adjusting the compression pressures to the diversifiec operating speeds and the corresponding forces of inertia is also possible by the disk valves 14-, the function 01 which can be affected by their construction and adjustment: The compression spring 16 is constructed in such a way that its spring tension is somewhat greater than the weight of the disk valve 14 so that the latter is lifted in the state of rest up to the stop 17. When the rotary piston 11 is moved, the air can enter without difficulty on the suction side through the lifted valve into the suction chamber of the pump. On the compression side of the piston, i. e. in the compression chamber of the pump, the increasing air pressure effects the closing of the other valve 14 to be found on this side, providing the piston speed and with that, the surge of air pressure is sufiiciently strong enough. The closing of this valve depends upon several factors, namely upon the dimension of the valve disk, the height of the valve upstroke and includes the cross section of passage, which can be regulated by means of the adjustable stop ring 18, and also depends upon the pressure spring 16 which can also be adjusted. The interaction of these three factors result that the closing of the valve during compression stroke is only effected as of a corresponding printing speed. As a rule, the valves are constructed and adjusted in such a way that the compression effect and with that the compensation of the inertia forces of the type bed of cylinder machines having approximately 5000 I. P. H. (impressions per hour) performance arises only at an impressional speed of approximately 2500 I. P. H. The valves 14 remain open at speeds lower than approximately 2500 I. P. H. so that there is no compression effect. The forces of inertia which change according to the square of speed are relatively weak in small-sized cylinder machines at speeds lower than 2500 I. P. H. so that within this lower range of speed the compensation of inertia forces by the nearly unchanging compression forces would not provide any advantage.

What I claim and desire to secure by Letters Patent is:

1. In a printing press having a frame of the reciprocating type bed, a rotary air cushion for compensating the forces of inertia of said type bed during its reciprocation comprising a cylindrical casing anchored on said frame, a vane coupled with said type bed and movable arcuately in said casing throughout the movement of said type bed, and a radial vane fixed in said casing, cooperating with said movable vane, said casing being provided with at least one port opening to the atmosphere and spaced circumferentially from said fixed vane to locate said selected portions of said casing, each portion alternately comprising compression and expansion portions in said casing.

2. Compensating device according to claim 1, in which there are at least two such ports spaced circumferentially from one another.

3. Compensating device according to claim 1, in which valves adjacent said fixed vane connect the interior of said casing with the atmosphere, said valves being biased to close when a predetermined pressure is attained in said casing, and means normally biasing said valves in open position.

4. In a printing press having a frame and a reciprocating type bed, drive means including a rotary shaft for reciprocating said bed and a device for compensating the forces of inertia of said type bed during its reciprocation comprising an enclosed rotary air cushion, said air cushion comprising a casing mounted on said frame with said shaft extending axially into said casing, a vane fixed on said shaft and movable arcuately in said casing and a radial vane fixed in said casing and cooperating with said movable vane to alternately define compression and expansion portions in said casing, the angular position of said movable vane on said shaft being such that said movable vane approaches said fixed vane as said bed approaches the ends of its stroke, the forces arising from the compression of air between said fixed and movable vanes being transmitted through said drive means to the bed to counteract the inertia of said bed.

5. In a printing press having a frame and a reciprocating type bed, a device for compensating the forces of inertia of said type bed during its reciprocation, comprising an air cushion mounted on said frame and having a relatively oscillatable casing and vane, said casing having a radial partition anchored to said casing, said casing being provided with ports radially disposed, said ports communicating with the atmosphere, said vane cooperat- References Cited in the file of this patent UNITED STATES PATENTS 404,394 Feister June 4, 1889 420,012 Huber Ian. 21, 1890 2,621,036 Rother Dec. 9, 1952

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