US2076773A - Machine for working printing machine cylinders, particularly copper cylinders in copperplate printing machines - Google Patents

Description

Apnl 13, 1937. o-r 2,076,773

MACHINE FOR WORKING PRINTING MACHINE CYLINDERS, PARTICULARLY COPPER CYLINDERS IN COPPERPLATE PRINTING MACHINES Filed April 22', 1956 2 Sheets-Sheet l Affarney Apni 13, 1937. GOYOT 2,076,773

MACHINE FOR WORKING PRINTING MACHINE CYLINDERS, PARTICULARLY COPPER CYLINDERS IN COPPERPLATE PRINTING MACHINES Filed April 22, 1936 2 Shets-Sheet 2 fig. 2

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5172;0[0 Andre GIG/02L Patented Apr. 13, 1937 UNITED STATES MACHINE FOR WORKING PRINTING M'A- CHINE CYLINDERS,

PARTICULARLY COP- PER CYLINDERS IN COPPERPLATE PRINT- ING MACHINES Francois Andr Goyot, Bellegarcle, France Application April 22, 1936, Serial No. 75,878 In France April 23, 1935 8 Claims.

This invention relates to a machine for working cylinders of printing machines, and particularly copper cylinders in copperplate printing ma- F chines.

Copper cylinders are usually ground on machines fitted with a natural or artificial grindstone which is rotated flatly on the cylinder and reciprocates along a line of contact, and polishing is effected on the same machines by employing stones of increasing fineness of grain, the final touches being applied by an emery paper pad which replaces the grindstone.

The employment of grindstones is open to numerous objections-such as high price, imperfect calibration, production of scratches due to the hard grain embedded in the stones, long duration of the process, and the necessity of constant attendance to regulate pressure.

It has been attempted to use machines equipped with a carriage carrying a steel or diamond tool for preparatory treatment, but as they are not accurately adapted to this kind of work, the resulting calibration is quite imperfect and, on the whole, inadequate. The defects of this method become particularly apparent, as very broad cylinders are used at present and some printing machines are fitted with cylinders the circumference of which must be exactly alike down to one-hundredth part of a centimeter.

' To eliminate these drawbacks the invention provides a machine capable of turning off the cylinders by means of a diamond to such a degree that the subsequent polishing is an operation of inferior importance and can be economically carried out on the same machine without interfering with the perfect accuracy previously attained.

The invention further provides improvements which permit the easy insertion and removal of even the heaviest cylinders without the use of block and tackle.

By way of example, the invention is illustrated in the accompanying drawing, in which Figure 1 is a general view of the machine; Fig. 2, a side view thereof; and Fig. 3 a diagram showing the manner of inserting the cylinders to be Worked.

According to the invention, and apart from details of construction of its various parts, the machine comprises on the left-hand side a fixed headstock a and on the right-hand side a movable tailstock b. To prevent vibration due to the frequently very long pivots of the cylinders to be ground the members a and b are fitted with the bushes c and d having a bore of sufficient Width to accommodate the pivots, so that the cylinder is held very near its center of gravity.

The machine is further provided with two vertical guides e and h one of which is arranged on either side thereof. The guide e carries the carriage f for the diamond tool g for finest grinding and the guide h supports the slide 2' which carries the polishing tools described below.

Owing to the vertical arrangement of the guides e and h, the intermediate portion 7 of the frame can be equipped for receiving and discharging the Water used in working.

The carriage f of the tool g is not in contact with the leading spindle k which effects its motion, but is driven by means of a second slide 11!. provided with a nut of known type which can engage the spindle k.

Feeding is efiected by means of a steel ball 11. disposed between two vertical plane abutments, so that vertically directed vibrations due to inaccuracies in motion, which are unavoidable even in the best made leading spindles, cannot be transmitted to the carriage f.

This special arrangement prevents the well known production of helical unevennesses of greater or lesser depth during the operation of the leading spindle.

Instead of a diamond tool a tool of suitable hard metal may be used.

Polishing of the cylinder for removing the very fine grooves due to the working of the tool is efiected by treating the copper surface with blocks of charcoal or other suitable material.

This polishing operation does not afiect the al- I The crank discs 10, p are carried by the-brackets q which are connected with the slide 2' and slide on the guide h, and by means of a suitable driving means a reciprocating rectilinear motion multaneously, a longitudinal motion which permits the polishing of the cylinder over its entire length, so that each point of the polishing memher is moved at the same speed, whereby the consumption of charcoal is considerably reduced.

The plurality of polishing tool carriers arranged with their arms on the member 0 permits simultaneous working of the cylinder at a corresponding number of points to shorten the time required for this operation.

While it is being polished the cylinder is rotated brackets a: each of which carriesan elevating screw as indicated in Fig. 3. By providing rails 2 on the elevating screws y at suitable height and rolling thereon the cylinder 2: with its pivots 2 the cylinder will i be automatically conveyed without effort to'the proper point in the axis of the members 0 and d of the headand tailstocks a and b. The provision of a support or projection 3 makes it possible to temporarily keep the cylinder in this position.

The rear slide 2' carrying the elevatingscrews y is then displaced to the left to cause the lefthand pivot 2 of the cylinder to enter the bush 0 of the fixed headstock a. The movable tailstook b provisionally connected with; the slide m by means of the tooth 4 is then displaced by thelatter to the right and receives the right-hand pivot .2. For this purpose, the tailstook b has a forked depression 4 therein into which the tooth 4' enters to connect the tailstook b with the slide m.

The removal of the cylinder is effected in re versed order. 7

Furthermore, to prevent dangerous vibrations the stationary headstock a is driven by a belt and a single pulley, and change of speeds is attained by means of a gear that is continuously variable independently of the machine.

To prevent absolutely deviations of the guide e from the perpendicular even if the foundation should yield a set screw 5 is provided under the center of the bed and is supported by a plate 6 disposed on the foundation.

A hand wheel I with centigrade graduation insures exact adjustment of the tool, so that a single adjustment provides exactly the same circumference for all cylinders.

Although the feed ofthe tool at each rotation of a cylinder amounts to only a few millimeters, the devices described permit'nevertheless high rotary-speeds to insure a short andeconomical working time. 7

As will be apparent from the preceding descrip- 'tion, the invention is not limited to the particular construction shown and described, but covers all possible embodiments and any combination of the elements.

I claim:

1. A machine for working the cylinders of printing machines, particularly copper cylinders for copperplate printing, comprising a frame, a fixed headstock disposed on one side thereof, a movable tailstook on the opposite side thereof, a bush on said headstock and said tailstock' for receiving the pivots of cylinders near the center of gravity thereof to prevent vibration, a vertical guide on each side of the machine, a carriage carried by one of said guides for receiving the diamond tools, a graduated hand wheel for ad- Justin-g the diamond tools relative to the circumference of the cylinders, a second apertured carriage carried by said other guide for supporting polishing means, a bed member formed intermediate between said guide members in the frame for receiving and discharging water used in polishing, a leading spindle, a driving slide on said spindle for said tool carriage, a nut for coupling said leading spindle with said slide, and a steel ball disposed between two vertical parallel abutments between said slide and tool carriage for transmitting motion thereto from said slide without vibration.

2. A machine according to claim 1, wherein a pawl connects the movable tailstook with the slide for receiving in its bush one pivot of a cylinder.

3. A machine according to claim 1, wherein the polishing means comprise twoapertured bearin-g brackets connected with the second carriage and sliding on the second guide, a crank disc on each bracket, means for rectilinearly and variably reciprocating said brackets, a connecting rod driven by said crank discs, a plurality of ad'- justable connecting members arranged on said rod, an arm on each of said connecting members, a carrier disposed at the end of each arm, and

charcoal blocks held by said carriers onto the circumference of a cylinder for polishing it, said blocks carrying outa circular and longitudinal motion for polishingthe rearwardly rotating cylinder over its entire length, said cylinder, at the beginning of the polishing operation,. being sprinkled with water introduced below the charcoal and collected and discharged by the intermediate bed member.

4. A machine according to claim 1, wherein in the center of the bed member a set screw is sup.- ported by a plate of the foundation for compensating deflections of the bed member.

5. In a machine according to claim, 1 means for facilitating the insertion and removal-of cylinders, said means comprising brackets detachably arranged in the apertures of the secand carriage, an elevating screw carried by each bracket, rails disposed on said elevating screws for moving thereonwith its pivots a cylinder introduced into the machine and thus automatically inserting the pivots in the bushes, and means for holding the cylinder in this position.

6. A machine for working the cylinders of printing machines particularly copper cylinders for copperplate printing, comprising a frame, a head stock and a tail stock both mounted on the frame, a carriage movable on the frame for holding a tool for making fine cuts on the cylinder, said carriage being provided on one side of the frame, and'a carriage .movable on the frame for polishing the cylinder to remove the. fine cut marks, said last-mentioned carriage being on the other side of the frame, and one of said carriages being capable of being moved so far parallel to the frame that the cylinder may be removed from the machine at right angles relative to the length of the machine.

7. A machine according to claim 6, in which the last-mentioned carriage is the carriage which

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