Construction of Cylinder Machines

A tech­nic­al account from 1897 of the con­struc­tion of cyl­in­der presses

Historical Article

From the 1897 Brit­ish Print­er by Mr James Trotter

B.P. read­ers are well aware, there is quite a vari­ety of cyl­in­der machines upon the mar­ket, and to describe the con­struc­tion of all the dif­fer­ent makes would occupy more space than would be allowed. At the same time, although there are so many dif­fer­ent makes of machines, the real dif­fer­ence is very small, and as a rule it is merely in such details as a swinging cyl­in­der, geared rollers, auto­mat­ic feed-board, etc., and with a day or two’s exper­i­ence any machine­man used to one make is able to handle anoth­er. The mech­an­ic­al motions, as applied to all machinery, are of two kinds: the motions which change the char­ac­ter of the action, and those which increase or dimin­ish its force. Print­ers have most to do with the first, for from front to back the print­ing machine is one con­tinu­al change of motion, and all who wish to be suc­cess­ful print­ers must not only know how to put a forme upon the machine, make it ready, and work off, but must obtain a prac­tic­al acquaint­ance with the work­ing of the dif­fer­ent parts of the machine they may be in charge of. This is gen­er­ally admit­ted, and yet how many mem­bers of the fra­tern­ity trouble about it? they drop the forme upon the bed, get the right pitch — and some­times the wrong one — lock up, make ready, start the machine, and for the next hour or two are con­tent with watch­ing the colour—or the fore­man, but nev­er fora moment try to ascer­tain the mech­an­ic­al move­ments of the dif­fer­ent parts which con­sti­tute the machine under their care.

The first piece of mech­an­ic­al power to be dealt with is the lever used for start­ing the machine. This is one of the simplest levers upon the machine, its work being to shift by means of a fork the belt from the loose to the fast pul­ley, and vice versa. In this con­nec­tion it is well to remem­ber that the strain upon a belt dimin­ishes accord­ing to the speed it runs at, and the fre­quent break­ing of belts is very often caused by run­ning the machine at too low a speed. Anoth­er cause of break­age is the sud­den strik­ing on of the belt to the fast pul­ley, and this may occur should the belt be some­what slack, the down­ward por­tion grip­ping the pul­ley while the loose sec­tion goes up with a jerk, thus — as might be expec­ted — caus­ing it to snap at its weak­est part.

Next may be noticed the gear­ing neces­sary upon all machinery where the mech­an­ic­al power of one part has to be trans­mit­ted to anoth­er. In this case we have the spur-wheels, which trans­mit their cir­cu­lar motion to the driv­ing-wheels, and turn shafts upon which are the vari­ous cams and eccent­rics. The eccent­ric is an appli­ance for obtain­ing the back­ward and for­ward motion of a crank, and is simply a circle revolving about a point away from its centre; as a rule it is sur­roun­ded by a ring or hoop, to which is attached the lever in a line with the centre of the circle, and as the shaft revolves it is thrown back­ward and for­ward. The cam — the action of which is to con­vert the cir­cu­lar motion of the shaft into a recip­roc­at­ing motion — is a curved plate, which, by the action of its curved edge, com­mu­nic­ates inter­mit­tent motion to anoth­er part of the machinery, its great advant­age being the extreme accur­acy with which it works.

Hav­ing viewed the mech­an­ic­al power, let us for a moment view the con­struc­tion. Take as a mod­el a quad-crown built by Messrs. John Elli­ott, Son & Co. Upon look­ing beneath, this machine gives some the impres­sion that vari­ous parts are miss­ing, but such is not the case; the machine is built strongly without any elab­or­ate detail, and is so arranged that should any­thing go wrong beneath it can be eas­ily got at. This machine has two side frames and four cross frames; the cross frames are bolted and pinned to the side frames, so that if a bolt works loose the pin will pre­vent the stay from shift­ing when the frames are in position.

Next come the lon­git­ud­in­al stays, which are bolted to the cross stays. Attached to these stays are the racks in which run the rack-wheels. Then the shaft on the left side is placed through the bear­ings in the lon­git­ud­in­al stays, and car­ries the left-side driv­ing-wheel, cam for double ink­ing, duct­or cam, and cam for auto­mat­ic feed board. Upon the right-side shaft are the right-side driv­ing-wheel, cams from which work the levers for open­ing grip­pers, lift­ing feed board, push­ing back cyl­in­der against the short stop, and upright lever for brak­ing the cyl­in­der. Fol­low­ing the pro­cess of con­struc­tion, next are put in the rack-wheels, the crank, and the driv­ing-wheels attached to them. Hav­ing got the neces­sary gear­ing in below, we come high­er up and fasten on the bowl rails to the cross stays, put on the bowls or run­ners, and attach them to the levers work­ing from the shaft of the rack-wheels. The main shaft­ing is next put through its bear­ings, of which there are five; two are cast with the side frames, two with the end stay, and one is bolted to the end stay between the pin­ions. Besides the pin­ions, the main shaft car­ries the fly-wheel and fast and loose pul­leys, with the driv­ing-wheels full in. Then the bed of the machine is put upon the run­ners, the ink­ing slab attached, and impres­sion bear­ers and side racks screwed on. The heav­iest part of the work — that of put­ting on the cyl­in­der — fol­lows. The cyl­in­der is put on with the bed full in, the loose cog-wheel put in pos­i­tion upon the end of the cyl­in­der shaft; the cyl­in­der brack­ets and brasses are then put on and bolted to the side frames; these brack­ets also sup­port the fly­ing drum. Next are fastened on the roller brack­ets; and mak­ing a move to the back, put on ink brack­ets, ink cyl­in­der and knife; upon the end of ink cyl­in­der the catch and con­nect­ing rod are fastened to the cam already men­tioned; an appli­ance for actu­at­ing the ink feed­er is worked from the same cam. Turn­ing to the oth­er side of the machine, fix on the brake-wheel to the shaft end of the cyl­in­der, put on the brake lever, and attach the brake and lever for push­ing the cyl­in­der against the short stop. All that now remains to be done is to put on the feed board brack­ets, attach the appli­ance for work­ing the points, and place the feed board in pos­i­tion. This done, the machine is now ready for the put­ting on of the belt, which will con­vey to the machine the cir­cu­lar motion of the revolving shaft.

To com­plete the work, the print­er then puts upon the cyl­in­der the neces­sary sheets and calico cor­res­pond­ing with the depth of beard upon the cyl­in­der, the lar­ger the bet­ter, secur­ing a forme of type. Then it is neces­sary to set the bear­ers and adjust the cyl­in­der, which, after being prop­erly set, should not again be altered only under very spe­cial cir­cum­stances. Mak­ing-ready may after­wards be undertaken.