US2950674A - Trip mechanism for printing machines - Google Patents

Description

Aug. 30, 1960 H. M. TAYLOR EITAL TRIP MECHANISM FOR PRINTING MACHINES 6 Sheets-Sheet 1 Filed Sept. 6, 1955 Aug. 30, 1960 H. M. TAYLOR EIAL TRIP MECHANISM FOR PRINTING MACHINES 6 Sheets-Sheet 2 Filed Sept. 26, 1955 Aug. 30, 1960 H. M. TAYLOR ETAL TRIP MECHANISM FOR PRINTING wxcnmas 6 Sheets-Sheet 3 Filed Sept. 26, 1955 F/g. a.

Aug. 30, 1960 H M. TAYLOR ETAL TRIP MECI-{ANISM FOR PRINTING MACHINES 6 Sheets-Sheet 4 Filed Sept. 26, 1955 Aug. 30, 1960 H. M. TAYLOR ETAL TRIP MECHANISM FOR PRINTING MACHINES 6 Sheets-Sheet 5 Filed Sept. 26, 1955 Aug. 30, 1960 H. M. TAYLOR ETAL TRIP MECHANISM FOR PRINTING mcnmzs 6 Sheets-Sheet 6 Filed Sept. 26, 1955 llnited States Patent @hice 2,956,674 Patented Aug. 30, 1960 'I'Rl? MECHANISM ron rnmrmo MACHINES Harold M. Taylor, Thorner, near Leeds, and Derek Stevenson, Leeds, England, assignors to R. W. Crantree Sons Limited, Leeds, England Filed Sept. 26, 1955, Ser. No. 536,642

Claims priority, application Great Britain Oct. 1, 1954 8 Claims. (Cl. 101-185) This invention relates to printing machines and par- I ticularly sheet-fed machines: such machines operate in constantly recurring cycles in each of which a sheet is individually presented, registered, printed and passed on as a printed product, it may be to delivery or to further printing operation.

The machines incorporate mechanisms to trip certain parts of the machine such as the printing and impression components, the inking mechanism, the moistening motion in the case of a lithographic machine and the sheettaking mechanism which takes a sheet in registered position: these mechanisms must be actuated at a certa n point in the printing cycle when required to do so by a check action which checks whether a sheet is properly presented and registered.

Such trip mechanisms are normally actuated by some moving part of the machine so as to be properly timed in the printing cycle and the check mechanism efiects its control by establishing connection between them and the parts to be tripped.

As such machines have so far developed, the trip mechanisms have generally been mechanically operated and the check mechanism has similarly been operated and has efiected its control on the trip mechanisms by some form or other of mechanical transmission: this all involves mechanical parts such as links, levers, shafts and so on and in the result sheet printing machines are somewhat complex, consisting as they do of a large number of parts which are not always easy to accommodate, are sometimes awkward and difiicult of access or render access to other parts of the machine diflicult, and add to the cost both of the machine and of its maintenance.

The main object of this invention is to provide an improved arrangement of trip mechanisms and check control for them.

Broadly stated, the present invention consists in providing an improved hydraulic transmission arranged to transmit in timed relation to the operation cycles of the machine hydraulic impulses for actuating the trip mechanisms.

The invention thus enables a considerable simplification to be made in such machines and the system according to this invention is flexible and so avoids positional difiiculties and enables easy access to the parts of the machine to be readily provided.

The check mechanism itself preferably also is arranged to effect its control by hydraulic transmission.

Thus in putting the invention into practical effect, there could be employed a single central control apparatus driven by some part of the machine for the purpose of controlling the hydraulic transmission to the various trip mechanisms, the control apparatus being connected to the mechanisms by hydraulic transmission lines which can be arranged as most convenient. This control unit can comprise a control box having a cam shaft geared to some part of the machine and having cams one for each trip mechanism involved, the cams operating, at

the correct time in the cycle of the machine, hydraulic valves or transmitters regulating the application of hydraulic pressure to hydraulic receivers to effect the actuation of the trip mechanisms.

The check mechanism would also exercise its control on the trip mechanisms by an hydraulic transmission but a mechanical transmission may be used.

it is to be observed that with this invention the tripping of the parts of a printing machine and the return of the parts to normal position is easily arranged to produce tripping and return in any required sequence: the normal mechanical tripping systems impose limitations of machine layouts by reason of complication and cost but this limitation is avoided by this invention which can readily be adapted to produce any desired sequence to suit any particular layout.

A further advantage of this invention consists in that a smaller motor would be required to operate the normal printing parts of the machine: the power required to operate the trip mechanisms need no longer be drawn from a moving part of the machine, but could be supplied by a separately driven hydraulic pump, the pump charging an hydraulic condenser from which the hydraulic system would draw its supply of power.

Gbviously the present invention is applicable to sheet fed printing machines, regardless of their manner of effecting the printing operation, i.e. whether by relief, lithographic or intaglio printing and in the case of lithographic printing by direct or off-set printing.

Reference will now be made to the accompanying drawings. in these drawings, Figure 1 is a side elevation of a printing machine showing the invention applied to it, Figure 2 is a diagram showing the installation of the parts provided in accordance with the invention and Figures 3 and 4 are respectively a sectional side elevation and a transverse section of the control box shown in Figures 1 and 2. Figure 5 is an elevation showing one of the trip mechanisms, Figure 6 is a diagram of a modified installation and Figures 7 and 8 are respectively a part-plan and an end elevation of a modified form of control box provided for the modified installation.

Reference will first be made to Figure l which shows one kind of machine to which the invention can be ap plied: this machine is what is known as a two-colour lithographic offset machine: it comprises an impression cylinder 1 having grouped about its periphery two blanket cylinders 2, 3, which receive impressions respectively from printing plate cylinders 4, 5, the impression applied to the blankets being transferred in succession to sheets S which are fed by a feed cylinder F to the impression cylinder 1. The sheets, after receiving the impressions, are taken from the impression cylinder 1 by grippers on a chain conveyor C which conveys the sheets to a delivery (not shown) or to a further printing unit for further treatment.

The plates on the printing cylinders 4, 5 are moistened and are inked in the respective colours, respectively by moistening mechanisms 6, 7 and inking mechanisms 8, 9.

Such a machine is in itself well known and further description is therefore believed to be unnecessary. It is however pointed out that provision is made in such machines to separate or trip the plate, blanket and impression cylinders i5 from one another and at least the inking mechanisms 8, 9, and it may be also the moistening mechanisms from 'the plate cylinders. This provision is necessary as is well known to enable the printing operat on to be discontinued under the automatic control of checks which are made on the sheets as to their presence at a given point at a given time,- their position when at that point, or as to the feed of two or more sheets when only one should be present.v

e 3 Such checks are made mostly at the feed to the machine. In addition, it is desirable that the machine attendant whether at the feed or at the delivery end of V the machine 'shall be. able 'to discontinue the printing operation, and for convenience this will also be regarded 'as a further check.

However, as is wellknown, .it is essential that the tripping of the printing and inking parts (and it may be the moistening'parts) shall be effected only at given times in the printing cycle and ina predetermined sequence and similarly that the parts shall be re-appliei only at given times and sequence. For this reason, in the normal machine, trip operating mechanism associated in timed relationship with the parts involved is provided but this mechanism is normally inefiective until rendered active by one of the checks. 7 Now the present invention is primarily concerned with improving the operation and the control of the trip mechanism and reference will now be made to Figure' 2. As indicated in that figure, use is made of 'a primary hydraulic transmission or circuit to eifect the tripping action under the control of the checks and under the control of means including a central timing box which determines the timing of the trip. The hydraulic transmission comprises primary hydraulic motors in the form of double-acting ram and cylinder devices: the tripping of the plate, blanket and impression cylinders is effected in the arrangement selected by tripping the blanket cylinders 2 and 3 in two senses one from the impression cylinder and the other from the related plate cylinder. For simplicity, the hydraulic motor for only one of these motions and for only one of the blanket cylinders is shown in Figure 2, this motor comprising a. pair of double-acting ram and cylinder devices 10, 11 one for each end of the cylinders: similarly a pair of double-acting ram and cylinder devices 12, 13 is provided to trip the inking rollers of each of the inking mechanisms 8, 9. Again a double-acting ram and cylinder device 14 is provided for controlling the operation of grippers to feed the sheets to the machine It will be understood that ram and cylinder devices would be provided and located as desired at the various I points in a machine, those shown in Figure 2 being only by way of example.

To effect the hydraulic operation of the primary ram and cylinder devices, the two sides of each are connected in hydraulic transmission lines 15, 16 each line having in it a reversing valve 17: each valve in one position connects the lines 15, 16 to the lines 18, 19 of an hydraulicpressure source or supply comprising for example a pump 20 which draws its supply from a sump 21 and a pressure accumulator 22, the lines 18, 19 thus being maintained under pressure and so holding the various ram and cylinder devices in a position (i.e. corresponding to on or o trip) as governed by the setting of the various valves 17.

As has been stated, the tripping ofli and on must be effected only at certain times and in a predetermined sequence: this is efiected by a timing control device 23 which is continuously operated, as by a gear 24, driven from some part of the machine. In the arrangement shown in Figure 2, each of the valves 17 is operated by a secondary hydraulic motor, e.g., a doubleacting ram and cylinder device the opposite sides of which are arranged to be connected to the pressure and return lines 25, 26 of a pilot or secondary hydraulic circuit including a pump 27 drawing its supply from the sump 21. Across the lines 25, 26 is a change-over valve 28 arranged to be actuated by a mechanical link 29 from the check points. The line 25 serves as the positive pressure or delivery line for the pump 27, and the line 26 serves as the low pressure or return line opening into the sump 21. In the normal position, the valve 28 connects the positive line 25 to a line or conduit 30 which is connected to those sides of the various ram and cylinder operating the valves 17 which will hold the valves in the trip on position, i.e. with the cylinders and other parts in their operative position. When however the valve 28 is operated the pressure line 25 is transferred from the line 30 to a line or conduit 31 extending to the timing valve 23: v at a time governed by the valve 23 the line 31 is connected to lines 32 extending to the other sides of the various ram and cylinder devices for operating the various valves 17 by the resulting hydraulic impulse transmitted to it. The valves 17 are thus thrown over at the required times and sequence to move the cylinders to the trip off position when the tripping operation is initiated by setting of the change-over valve 28 by the check responsive device 29..

Reference will now be made to Figures 4 and 5 which show the timing valve assembly 23. The assembly comprises a shaft 32 to which the gear 24 is secured and on the shaft is a number of cams 33 one for each changeover valve 17. Each cam is arranged to operate a pilot valve 35 which controls the communication between a pressure duct 36 connected to the line 31 and passages having connectors 37 one for each of the lines 32 leading to the ram and cylinders to operate the reversing valves 17. The cams 33 are arranged for adjustment on the shaft 32 so that the timing of the operation of the corresponding valve 17 by the hydraulic impulse can be set to suit requirements. The control valve assembly can obviously be adapted to suit the requirements of different machines by the selectionof the number of cams 33 provided.

It is convenient here timing control valve assembly which is contained -in a casing 38, the various lines can be taken to the points of supply and control as found most convenient: these lines are constituted by flexible pipes as is indicated most clearly in Figure 1 from which will be apparent the clean appearance of a machine according to this invention. I

The flexibility of the transmission obviously avoids the difliculties of accommodation and location which the usual mechanical transmission presents and the pants required can readily be arranged and adapted to the various kinds and arrangements of sheet printing machines.

In Figure 1 is shown in a practical disposition the various ram and cylinder arrangements foractually moving the parts concerned and in Figure 5 the construction is shown in greater detail as applied to one ,of the blanket cylinders i.e. to the cylinder 2. Thus as shown in Figures 1 and 5 each of the blanket cylinders 2, 3 has its shaft ends mounted in two eccentric bearings 39, 40: movement of one bearing trips the blanket cylinder 2 (or 3) to and from the cooperating plate cylinder 4 (or 5): the other bearing trips the blanket cylinder to or from the impression cylinder 1.

Each of the eccentrics is arranged to be operated by a primary hydraulic motor or double acting cylinder device equivalent to those'shown at 10, 11 in Figure 2. As is shown more particularly in Figure 5, the ram rods 42 of the devices are connected to extensions 41 on the eccentrics: in the case of the connection 'for the ram and cylinder which trips the blanket cylinder from the impression cylinder 1, the stroke of the ram (indicated at 43 in Figure 5) is arranged to be adjustable to fine limits for which purpose the cylinder 44' for the ram receives a. screwed plug 45 which is adjustable through a worm and wheel gear 46 having an indicating scale 46. p

In the case for moving the inking mechanisms 8, 9, the double acting ram and cylinders 12, 13 can operate through a link 47 on a shifting cam 48 which lifts and lowers the rollers of the inking mechanism; as to the moistening mechanisms 6, 7 these can if required to be operated be controlled as shown by an extension ofthe ram and cylinder operating the inking mechanisms, the extension operating through the levers 49 and links 50.

to observe that by the use of the 4 iii.

It is desirable that the controlled mechanism shall be capable of being tripped at the will of the operator but still at the proper time: this can be very simply effected by providing hand-operated change-over valves indicated at 51 as shunting the change-over valve 28, these valves 51 however still being under control of the timing valve 23.

Reference will now be made to Figures 6, 7 and 8 in which the timing assembly relies on a mechanical control instead of the hydraulic control described, the function being the same as that of the hydraulic control. In this construction the reversing valves 17 are operated by push-pull rods 52. The rods are prepared for operation under the control of a check trip rod 54 which, like the rod 29 shown in Figure l, is operated from the check points. The actual operation of the rods 52 is eifected at the proper time and in proper sequence by cams 55 on a shaft 56.

The trip rod 54 is coupled to an arm 57 on a rock shaft 58 having a series of arms 59 one for each arm 57 and hence one for each valve 17: each arm 59 is connected via a rod 63 and springs 61 with a T-shaped rock lever having one of its arms 63 connected to one of the push-pull rods 52: each of the other arms of the rock lever is provided with two pins 64 to be engaged by abutments 65' on a forked component 65 which is caused to rise and fall by one of the cams 55 which operates through a bell-crank lever 66 biased by a spring 67 against the cam.

In the normal condition the various components 65 rise and fall idly: when however the trip rod 54 is operated from the check point, the shaft 58 is rocked so as to change-over the positions of the T-levers to prepare them respectively for operation by the associated forked component 65 when the associated cam 55 next lowers it.

Thus, in the mechanical arrangement also, the check prepares the various reversing valves for operation but the actual time of operation is governed by the timing cams 55.

We claim:

1. A rotary offset sheet printing machine comprising a printing cylinder; a blanket cylinder; an impression cylinder and an inking mechanism to ink the printing cylinder; means for feeding sheets to the machine for travel along a path through the machine determined by the machine cylinders; a number of double-acting hydraulic units each including ram means selectively subjectable to hydraulic pressure in opposite directions respectively to move the cylinders and the inking mechanism positively into and out of cooperation; a source of supply of pressure liquid to operate the said hydraulic units positively in opposite directions; reversing valves to control the application of pressure liquid to the ram means of the various hydraulic units selectively in opposite directions for operating said ram means positively both to establish and to relieve cooperation between the cylinders and the inking mechanism; a normally inactive valve-actuating means operated in synchronism with the machine for actuating the valves in a predetermined sequence to eifect relative movement between the cylinders and the inking mechanism; and sheet check means functioning in said path for controlling operation of said valve-actuating means.

2. A rotary sheet fed offset printing machine as claimed in claim 1 and wherein the normally inactive 'valve operating means includes a cam unit gear driven by the machine, the unit comprising a number of valveoperating cams set in the relationship for effecting operation of the valves in the predetermined sequence.

3. A printing machine as claimed in claim 1 and wherein separate hydraulic units are provided for establishing and relieving cooperation between the blanket cylinder on the one hand and the printing and impression cylinders on the other hand, the said units being controlled by separate reversing valves so that the times of relieving and establishing cooperation can be separately set.

4. A printing machine as claimed in claim 1 and including two hydraulic units for moving said blanket cylinder, one of said two hydraulic units for moving said blanket cylinder into and out of cooperation with said printing cylinder, and the other of said two hydraulic units for moving said blanket cylinder into and out of cooperation with said impression cylinder.

5. A printing machine as claimed in claim 1, and in which said hydraulic units respectively comprise means for adjusting the ram means stroke thereby to vary the limiting position of the units in applying the associated cylinder into cooperation.

6. A rotary sheet-fed olfset printing machine comprising a printing cylinder; a blanket cylinder; an impression cylinder and an inking mechanism to ink the printing cylinder; means for feeding sheets to the machine for travel along a path through the machine determined by the machine cylinders; a number of double-acting hydraulic units each including ram means selectively subjectable to hydraulic pressure in opposite directions respectively to move the cylinders and the inking mechanism positively into and out of cooperation; a source of supply of pressure liquid to operate the said hydraulic units positively in opposite directions; reversing valves to control the application of pressure liquid to the ram means of the various hydraulic units selectively in opposite directions for operating said ram means positively both to establish and to relieve cooperation between the cylinders and the inking mechanism; hydraulically operable means to actuate said valves; pilot valves to control the supply of pressure liquid to said hydraulically operable means; means operable in synchronism with the machine for operating said pilot valves in a predetermined sequence; and sheet check means for controlling conjointly with said pilot valves, the supply of pressure liquid to said hydraulically operated means thereby to elfect relative movement between said cylinders and said inking mechanism.

7. A rotary sheet-fed offset printing machine comprising a printing cylinder; a blanket cylinder; an impression cylinder and an inking mechanism to ink the printing cylinder; means for feeding sheets to the machine for travel along a path through the machine determined by the machine cylinders; a number of double-acting hydraulic units each including ram means selectively subjectable to hydraulic pressure in opposite directions respectively to move the cylinders and the inking mechanism positively into and out of cooperation; a source of supply of pressure liquid to operate the said hydraulic units positively in opposite directions; reversing valves to control the application of pressure liquid to the ram means of the various hydraulic units selectively in opposite directions for operating said ram means positively both to establish and to relieve cooperation between the cylinders and the inking mechanism; a normally inactive valve-actuating means adapted to be rendered active to be operated in synchronism with the machine and comprising a mechanical transmission to actuate the said valves in a predetermined sequence to efiect relative movement between the cylinders and the inking mechanism; and sheet check means functioning in said path for controlling operation of said valve-actuating means.

8. A rotary sheet-fed offset printing machine comprising a printing cylinder; a blanket cylinder; an impression cylinder and an inking mechanism to ink the printing cylinder; means for feeding sheets to the machine for travel along a path through the machine determined by the machine cylinders; a number of double-acting hydraulic units each including ram means selectively subjectable to hydraulic pressure in opposite directions respectively to move the cylinders and the inking mechanisni positively into and out of cooperation; a source of supply of pressure liquid to operate the said hydraulic units positively in opposite directions; reversing valves to' control the application of pressure liquid to the ram means of the various hydraulic units selectively inopposite directions for operating said ram means positively both to establish and ,to relieve cooperation between the cylinders and the inking'mechanism; a rotatable cam unit comprising a plurality of cams; means for driving said carn unit continuously during and in synchronisrn with said cylinders; 'normally'inefiective drive transmitting connections respectively between said cams and said reversing valves; and sheet check means functioningtin said path for rendering said drive transmitting connections effective for transmitting drive from said cams to 2,157,240 2,205,720 Goebel et al. June 25, 1940 2,216,565 Eckhard Oct; 1, 1940 32,267,380 Tyler -1. Dec. 23, 1941 2,419,403 Horton et al Apr. 22, 1947 2,539,361 Cannon Jan. 23, 1951 2,689,524 Wood Q Sept. 21, 1954 2,773,445 Wood Dec. 11,1956

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