US2880670A

US2880670A - Master clip arrangements for hectographic duplicating machines

Info

Publication number: US2880670A
Application number: US535436A
Authority: US
Inventors: Brougham Leslie Ernest; Brown Roland
Original assignee: Block and Anderson Ltd
Current assignee: Block and Anderson Ltd
Priority date: 1954-09-22
Filing date: 1955-09-20
Publication date: 1959-04-07
Anticipated expiration: 1976-04-07

Description

Apnl 7, 1959 E. BROUGHAM ETAL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES Filed Sept. 20. 1955 5 Sheets-Sheet 1 8 m a m Alum rats .Filed Sept. 20; 1955 April 1959 L. E. BROUGHAM ET AL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC 1 DUPLICATING MACHINES 5 Sheets-Sheet 2 F'LGb-Q FIG].

yM,A rig??? 5 Sheets-Sheet 5 p 1959 L. E. .BROUGHAM ET AL MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES Filed Sept. 20, 1955 n? W J l...i lL+l||||1i|| ulillilrl f -lwl ilfi 551% -Lm -i M I r c m M s m \EQWQ 3m 9 &

mw R M a Q wQ mdE Nil-kw a amw Nm v m 9.

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| 'E. BROUGHAM ET AL A ril 7,1959 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES 5 Sheets-Sheet 4 Filed Sept.. 20, 1955 m M m a we @QE 5% 8 mo\ mmw P 3 m9 k mm 5 mm a a Pa... 3 3 u M g inwl much N FFEHPILL F nn!- Lvj..- NW

April 7,- 1959 L. E. BROUGHAM ET'AL 2,880,670

MASTER CLIP ARRANGEMENTS FOR HECTOGRAPHIC DUPLICATING MACHINES 5 Sheets-Sheet 5 Filed Sept. 20, 1955 Z; M? w 2% 59A/ /W/ MASTER CLII." ARRANGEMENTS FOR HECTO GRAPHIC DUPLICATING MACHINES Leslie Ernest Brougham, and Roland Brown, London, England, assiguors to Block & Anderson Limited, London, England, a British company Application September 20,1955, SerialNo. 535,436,

Claims priority, application Great Britain September22, 1954 13. Claims. (Cl. 101-4325.)

The present invention relates to. master clip arrangements in hectographic duplicatingv machines and more particularly to adjusting mechanisms. for the master clips of such machines.

' In machines of the to whichthe invention re: lates, one or more hectographic master sheets carrying typewritten or other matter in mirror scripare, each secured, by means of a. device known as a clip, to a rotatable printing drum. co-operating with a counter pres-. sure roller to. form a printing, couple, to which are: fed copy sheets. whose upper surface is moistened with a solvent for the hectographic ink.

In one of such arrangements especially adapted for the printing of data for production control systems, the rotatable drum carries two master clips, one of which is a fixed clip extending substantially the full, length of the drum, whilst the second clip is a movable clip ex:- tending approximately half the length of the drum' and positioned behind the fixed clip with respect to drum rotation, mechanism being provided for traversing the movable clip to thefull extent. along the drum. Such a machine is adapted to produce in one operation a copy of a fixed heading master and of one or more selected lines of an item master sheet. For this purpose the heading master sheet is. placed in the fixed cli'p with the heading portion towards the. centre of the drum, and the item master sheet is placed in the, movable clip and underneath the heading master. A masking; sheet is also, placed in the fixed clip in such a position as to expose the one or more items of the movable master sheet between the mask and the heading master. Copies are then taken of the heading together with the selected single item or items from the movable master sheet. Other items are selected by shifting the movable master clip along the drum. The normal spacing between the heading master and the mask is of one line of" the item master, and when it is desired to print items of two-line width or more, it is necessary for the operator to open. the fixed clip and to adjustthe position of the masking sheet to give the required spacing, In doing so care must be taken to avoid shifting the heading master, which, since it is carried in the fixed clip, is also freed by opening the clip. Alternatively, a supplementary narrow mask must be used in conjunction with the existing. masking sheet, and for this purpose also operating skill is required to obtain correct adjustment. Whether or not an auxiliary mask is used, such operations of inserting and adjusting the additional mask or of adjusting the mask in the fixed clip, add tothe number of manual operations therefore increase the time printed copies. It is accordingly one object of the present. invention to provide a clip arrangement; in amachine of the kind above referred to wherein rapid and accurate adjustment of the spacing or interval between the heading master and the mask may'be effected. This object is achieved broadly by' providing, instead of a fixed clip taking up the full length of the drum, twousually fixed: at the width" to be performed and and expense of producing the the direction IV-IV' of Fig. 1.

2. clips, preferably alignedin the drum surface, one of wh ch s fix c p e tend n e a ni nt p tion of the drum length, for example onev half, whilst he e he is n. dli t b e nl wh h. ayh d. 5 le th is o he um un t y s eps c r e p nding. to the; minimumwidth of; any item which is to be printed. fmm the ovab mas e According to the. present invention therefore, in a romy hecmg ap i dupl atin ma hi w l ps. a e p vid d i l m n par lel o he r m ax s 16. i; aid l psi s ed, and. he h r; o d, l ps bein ash in ah e g h is o h r m in un a y st ps- Ac or i o neth r' spe t of he i ti i. a m s er: l p-- ar a gemen i a ta y hec a r i d is t ns machine, comprises a fixed master clip extending for a par o he en th o m ium movable m st r ip traversable lengthwise of the drum and lying; behind the fixed master clip. in the direction. of the rQla-tion of the drum. during printing, I aligned. with respect. to. the length of the drum with the said fixed master clip, the said adjustable master clip being. adjustable in theforward and. reverse directions n u i a y s ps- Further features. ofv the invention. relate. to a preferred form; of space shift mechanism. for an adjustable. clip whereby. the said. clip may be shifted both in the forar and r v rse d re i y m n of a Pu h m4 a ra k. an pawl. ech n m- S h p e r d orm of. hi mecha sm amp s a.

to, the. adjustable clip and. coeoperating v/ithv two pawl s.

one of which (the forward feed pawl) arrangedin. a the length of the push. rod.

fixed position with respect to, andco-operates with. one rack, whilst the. second pawl (herein referred to as the check pawl), is. secured to. a at n a e pe i o ith re p ct drum a coopera alternately w hhh e s Cl p 7 opening means are also provided whereby the adjustable l p and. h fixe l p ay e open d by a. c mmo ro e be i espec v e he a ju p s t on f e adjusta l cl p An x mple, of the mast l a ran emen a cord ng to the. inventio w l .now he e c b d in m e d t l with efe ence toh pan in d g E gure I s a s t on. taken thr gh t P ntin dru how-i a arra g men o clip p c ng me ha ism scc d ng. t0 t i vent en.

Figure 2 is. atten vie a a a ge calefi t 4mm from the direction of 11-11 in Fig. 1 but omitting the rum n plat and h at n Figure 3 is an elevation of the drum and clips from the direction II I-III of Fig. 1'.

Figure 4 is a view' of the clip spacing mechanism from Figure 5 is another view on a larger scale of part of the same clip spacing mechanism when the drum is rotated' 180 from the position in- Fig. 1

s Figure 5a is a detail of part of Figure 5.

Figures 6" and 7 are cross-sections taken as indicated through the clip spacing mechanism of Fig. 5.

Figure 8 is an end elevation of the right hand drum end plate with the drum in adifferent position from Fig-- ure-l and showing further details of the clip spacing: mechanism and details of the clip opening mechanism..

Figure 9 is an elevation of a clip opening mechanism for one oi the clips shownv in Fig. 2.

Figure 10 is a detailed view of part of a latch mechanism shown in Fig. 9.

carrying' a bearing boss 4 whereby the. drum may be and an. adjustable master clip.

u le. q hed a k fix to the length vef the.

journalled for rotation in the side frames of the machine (not shown). It will be understood that the drum cooperates with a counter-pressure roller which may be of known construction and that the details of the counterpressure roller and the drum mounting form no part of this invention and will not therefore be described.

According to the invention which are indicated by the general references 5 and 6 and which are aligned in a common radial plane (XX, Fig. 2), of the drum, the drum being shown with this plane vertical purely for a showing of the parts in Fig. 1. Clip 5 is a fixed clip of about half the drum length which remains at the right-hand side of the drum and is intended to carry a heading master which is not moved along the drum, and such clip will be referred to hereinafter as heading clip. Clip 6 is arranged at the lefthand end of the drum as viewed from the front of the machine and occupies rather less than half of the drum length to allow for the required axial movement of the the drum carries two clips 19 of the ratchet plate as seen in Fig. 5, which rack clip by the clip spacing mechanism to be later described.

This clip, which will be referred to herein as the movable mask clip, is intended to carry a movable mask when the machine is operated for the selective printing of items from a movable master sheet.

The drum also carries a third clip, general reference indicated by the 7, which is adapted to be moved the full length axially of the drum by a further clip spacing mechanism to be referred to below. This clip, which usually occupies about half the length of the drum, and is placed behind clips 5 and 6 in the direction of drum rotation, is intended to carry a master sheet from which a selected item or items may be printed in conjunction with the heading when the respective clips are brought into their appropriate position, and may therefore be referred to as the movable item clip.

The drum is slotted along its length as shown in Figure 2 to provide a gap of sufiicient dimensions to receive the clip assemblies each comprising the clips above referred to with the accessory parts for mounting the clips in the drum.

The blade of the movable mask clip 6 is supported as shown in Figs. 2, 6 and 7 between parallel back and front

clip guide plates

8 and 8a, which are secured together in any suitable manner. The front guide plate 8 which is shaped to form a clip seat is rebated to receive the rectangular lip 12 of the clip 6. The back is supported against a backing plate 9 which is rigidly fixed in the drum. The clip is held in the closed position by retaining springs 13 anchored to plate 8a and is slidable radially between the

plates

8 and 8a for opening by a mechanism to be described below. The clip 6 is also provided with an operating mechanism now to be described for obtaining stepwise adjustment of the clip assembly, including the clip 6 and the

guide plates

8 and 8a, away from or towards the fixed master clip 5, these directions of adjustment being referred to as forward and reverse. Forward feed motion is positive but reverse motion is obtained by the tension of a spring 11.

A bracket 15 secured to the adjustable clip assembly by screws 16, carries a ratchet plate 17 provided on the opposite inside edges with two series of ratchet teeth 18 and 19, each having a pitch equal to the width of one .line of the printed matter from which copies are to betaken, for example equal to /3 inch, and each of which series is staggered with respect to the other by half the length of one tooth. The attacking (straight) edges of all the teeth are directed to the same side, in the present arrangement the right-hand side, whilst the sloping edges are on the left-hand side.

Two operating

pawls

20 and 21, herein referred to as the forward feed and check pawls, are arranged to co-operate-with the said rack teeth. The forward feed pawl 20 is rotatably carried between two

collars

22, 32

guide plate will be referred to as the feed rack. The spacing rod is urged into its right-hand (reverse) position by means of a compression spring 28 mounted between a fixed collar 29 on the rod and one of the bearing brackets 26 above referred to. The motion of the rod in the right-hand (reverse) direction is limited by a collar 30 secured to the rod at a suitable point. The forward motion of the rod is suitably limited to a distance sulficient to advance the feed rack one tooth as will be described below. The check pawl 21 is freely mounted on the spacing rod in a fixed position with respect to the drum and, for this purpose, is held between two bushes .33 and 33a on the fixed bracket 24. The said check pawl 21 is likewise spring urged into contact with the above mentioned feed rack of the ratchet plate. The

push rod is also provided with pawl releasing means, which may consist as shown in Figs. 6 and 7 of a plate 34 of a length suflicient to cover the maximum spacing between the pawls. The plate 34 is suitably keyed to the rod by means of lugs 37, and upon turning the rod clockwise through a small angle the plate 34 comes into contact with

tail portions

35, 36 of each pawl and so lifts the pawls clear of the rack for the purpose later referred to. A spring 38, which may serve for biassing the pawl 21 on to the rack and partly for returning plate 34 and rod 23 counter-clockwise, is anchored between the tail 35 of the check pawl and the back plate 9.

v The above described arrangement allows the adjustable clip 6 to be racked forward one space at a time. Upon operating the spacing rod to the left the forward feed pawl 20 engages one of the teeth of the feed rack 19 and moves the rack plate, and with it the clip, to the left one tooth space whilst the check pawl 21 is lifted by the motion of the rack and falls into the notch of the next adjacent tooth. The feed stroke of the rod is limited to one tooth by the distance between lug 37 and the fixed bush 33. By allowing the rod to return and repeating the stroke, the rack, and with it the adjustable clip, may be shifted in the forward direction by the required number of spaces according to the width of any.

item required to be printed from the movable master sheet. Fig. 5 shows the clip and rack fully spaced to the left. Fig. 1 shows the opposite position. It will be understood that the total spacing is limited only by relative lengths of the clips 5 and 6 and that the rack length could be chosen to suit this relation. However, it has been found that in the example described a total spacing of two inches is sufiicient. During this forward motion the check pawl locks the ratchet plate in each new position and the opposite rack takes no part in the motion.

When it is desired to return the adjustable clip from the position shown in Fig. 5 to the position of Fig. 1, the spacing rod is rotated by a small clockwise angle sulficient to lift both the feed pawl and the check pawl from their respective notches. Since the racks are staggered by one half the length of each tooth, the check pawl, upon leaving a notch in the forward feed rack, enters an adjacent notch on the opposite rack, as shown in Fig. 5a, thus preventing the full return of the adjusta, small angle, the ratchet plate and withit the adjustable clip 6 is moved under spring tension in the reverse direction by the length of one tooth, i.e., the width of one line of the movable master and by repeating this operat-ion the clip can be fully returned.

Mechanism will now be described whereby the clip spacing rod may be manually operated from the operators position at the front of the machine.

Referring now more particularly to Figs. 1, 2 and 8, the latter of which shows a view of the right-hand drum end plate from the direction II-II of Fig. 1 after the drum has been rotated inthe anticlockwise direction through somewhat more than 90 from the position of Fig. 1 into the rest position in which the clips may be opened for inserting the master sheets.

The right-hand end of the clip spacing rod, When in the normal position, rests against one arm 41 of a bell crank pivoted at 42 at the back of the drum end plate 3, and the lower arm 43 of the bell crank projects through a hole 44 in the drum end plate and makes contact with the: nose of a lever 45 pivoted at 46 on the outside of the drum end plate.

The right-hand end of the clip spacing rod also carries a crank 48 keyed thereto which has a crank shaft 49 projecting through a hole 50 in the drum end plate and engaging a slotted arm 51 of a bell crank pivoted at 52 on the outside of the drum end plate.

A rock lever 53 is provided at 54 and the equal arms thereof each carry a roller 55. The above-mentioned bell crank arm 51 is biased by a spring 56 to bring the second arm 57 of the bell crank against one of the rollers 55 whilst the lever 45 is biased by a spring 58 to seat the heel of lever 45 against the second roller 55 of the rock lever 53, and stops 59 and 60 are provided to stabilise the levers in the position shown corresponding to the normal rest position of the clip spacing rod retracted fully to the right of the drum.

A further lever 61 is pivoted at 62 in the right-hand side frame of the machine (not shown) and in such a position that when the drum is in the master changing position shown in Fig. 3, a concentric operating surface 63 of the lever 61 is symmetrically placed with respect to each of the rollers 55 of the rock shaft 53. A manual operating lever 65 is pivoted in a convenient position at 66 in the right hand side frame (not shown) and is connected to the lever 61 by a linkage comprising the arm 67, link 68 and lever 69 which is slotted at 70 to receive the pin 64 of lever 61. The lever 65 is normally centred in the neutral position in Fig. 8, by means of a centering device comprising arms 71 frictionally connected to lever 65 and embracing a fixed screw 74 secured in the side frame and carrying operating pins 72 which are connected and drawn together into contact with arm 67 by spring 73. Upon moving the operators lever'65 from neutral in the feed direction the lever and linkage operate to rotate lever 61 anti-clockwise and thereby to push the clip spacing rod forward through lever 45 and bell crank 41-.43. Upon moving the operators lever 65 in the reverse direction the lever and linkage operate to rotate lever 61 in the clockwise direction and thereby to oscillate the clip spacing rod through bell crank 515,7.

The fixed heading clip 5 is of similar construction to the movable mask clip 6 insofar as concerns the mounting of the clip between the clip guide plate 78 and the clip seat 79, and the details of this fixed clip may follow known practice and will therefore not be further described.

It will be understood that a clip opening mechanism is provided for opening both the fixed clip 5 and the movable mask clip 6 when the drum is in the master changing position shown in Fig. 8. The main elements of a clip opening mechanism for opening both clips 5 and 6 from one control member are shown in Figs. 1,. 2 and 8 of the drawing and comprise a clip lifting shaft whose axis is shown at 0 comprising a square rod 80 extending through the length of the drum and journalled in bearings (not shown) in the end Plates 2 a d 3 l and pawl arrangement 6 thereof. The clip lifting shaft carries two pairs of clip lifting arms indicated by 81 and 82 respectively for open? ing the fixed clip 5 and the adjustable clip 6. For this purpose the clip guide plates 78 and 9 of the two clips have pairs of slots at 83 and 84 respectively to receive the

clip arms

81 and 82 upon which are carried rollers 85 engaging upon the inner edge of the clip blade. The clip lifting shaft carries at its right-hand end a clip lifting lever 86 which is operated through a rock shaft 87 pivoted at 88 on the drum end plate. The rock shaft is adapted to be operated by a lever mechanism (not shown) arranged in the side frame of the machine, when the drum is in the master changing position. Details of such a mechanism are not shown here but an example thereof is described in our British patent application No. 4,240/54. Rotation of the rock shaft turns the lever 86 in the anti-clockwise direction and thereby causes the lifting arms to open both of the clips simultaneously. Since the clip guide plate 9 remains stationary whilst the clip 6 is adjusted along the drum, the arms and rollers 82 and are effective to open the clip in any of its adjusted positions provided that the inner edge 89 of the clip blade is parallel to the drum axis for the required distance as shown in Fig. 5'. T It will be understood also that the movable item clip 7, which is carried within a guide plate 91 and clip seat 92 in a similar manner to clips 5 and 6, must be provided with clip opening means in order that the master sheet may be inserted therein when the drum is in the position shown in Fig. 8. The clip opening mechanism provided for that purpose may be of any convenient type and oneexample of the kind in which the clip may" only be opened in its end position corresponding to that shown in Fig. 3 is shown in Fig. 9 of the drawings, wherein the clip blade is provided with a pair of inwardly projecting pins 93 which have their inner ends close to a pair of sector-shaped operating levers 94 forming the side limbs of a parallel linkage whose lower limb is a connecting link 95. The connecting link 95 lies opposite a nose 96 carried at the end of a shaft 97 which is journalled and axially displaceable in the bearing boss 4 of the end plate. The shaft carries at its outer end a face cam (not shown) which is adapted to be operated by a lever in known manner to displace the shaft axially to bring the nose 96 into contact with the link and thereby to operate the parallel linkage and to lift the clip by means of the pins.

To prevent axial movement of the clip during opening a latching device is provided as shown in Figs. 9 and 10 comprising a bell crank pivoted at 99 to the back plate 91 and having a long arm 102 adapted to hook over a pin 103 fixed to a bracket 104 on the drum end plate, and a short arm 105 connected by a spring 106 to the link 95. The latch is normally held open by a stop 107' on link 95 and is closed during the initial idle movement of the link 95 before the levers 94 contact the lifting pins 93.

Mechanism is also provided for traversing the clip 7 along the drum. Such mechanism is preferably of the kind in which a clip operating rod passes co-axially through one end of the drum end plate 3 and bearings 4, and makes connection inside the drum to a lug 101 secured to the clip guide plate 91 and forming a sleeve bearing for the rod, whereby the drum and clip may rotate round the rod whilst the rod is moving the clip axially along the drum, during which movement the clip assembly is guided on a rod 98. The rod is connected outside the drum to a clip traversing carriage (not shown) which is preferably of the kind described in our British patent application No. 1 6,486/55 and comprises a rack extending parallel to the .drum and externally thereof either outside or between the side frames of the machine, control means being provided for obtaining step-by-step or full travel of h clip under the operators control. The movable master is placed in the said movable item clip 7, and the heading master is placed in the fixed heading clip 5. A masking plate 90 (Figs. 2 and 3) is fitted to cover the drum gap to ensure correct entry of the heading master in clip 5. A masking sheet is placed in the movable mask clip 6, which, as described above, is axially aligned with the fixed clip. The clip 6 is normally spaced from the fixed clip by the width of one item of the movable master, this Width being shown at d in Fig. 1, so that in the normal operating position the whole of the fixed master and one item of the movable master are exposed for printing. By operating the clip spacing rod as above described the width of the movable master exposed for printing can be adjusted to 2, 3, 4 or any convenient number of spaces up to the maximum provided by the rack and pawl. Hence the printing of items of variable width from the fixed master and of a heading from the heading master may be effected without carrying out manual masking adjustment or mask changing operations which have formerly been necessary in machines of this type.

. We claim:

1. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip for securing an item master sheet to said drum, said clip being located in a drum slot extending axially of said drum and being adjustable over substantially the full axial length of said drum, first step-by-step shift means for moving said master clip within said drum slot in unit steps of predetermined length, a fixed position master clip disposed axially of said drum at a position angularly spaced forwardly from said first axial movable clip in the direction of drum rotation, said fixed position clip being located at one end of said drum and being of lesser axial length than said drum, a second axially movable clip for securing a masking sheet, said second axially movable clip being located in a drum slot extending axially of the drum at a position just angularly spaced forwardly from said first axially movable clip in the direction of drum rotation, said second axially movable clip being adjustable over a range of movement embracing that part of the drum length which is not embraced by said fixed position clip and second step-bystep shift means for shifting said second axially movable clip lengthwise of the drum in unit steps of predetermined length in either axial direction.

2. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip for securing an item master sheet on said drum, said clip being movable in a drum slot extending axially of the drum for substantially the full axial length of said drum, first step-by-step shift means for shifting said master clip within said drum slot in unit steps of predetermined length, a fixed position master clip extending axially of the drum and substantially parallel to said first axially movable clip but spaced angularly from said first movable clip in the direction of drum rotation, said fixed position clip being of restricted length less than the length of said drum and being positioned at one end of said drum, a second axially movable clip for securing a masking sheet on said drum, means defining a second axial drum slot in said drum in continuation of said fixed clip over that part of the drum length not occupied by said fixed clip, said second axially movable clip being located in said second drum slot and second step-by-step shift means for moving said second axially movable clip in either direction in said second drum slot in unit steps of predetermined length.

3. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip for securing an item master sheet to said drum said'clip being located in a drum slot extending substantially the full axial length of said drum, first step-by-step shift means for shifting said first movable clip lengthwise of said drum, a fixed position master clip parallel with and angularly spaced forwardly from said first movable clip in the direction of drum rotation, a second axially movable clip for securing a masking sheet, said second movable clip being located in a drumslot parallel with and angularly spaced forwardly from said first movable clip in the direction of drum rotation, and second step-by-step shift means for adjusting said second movable clip in either axial direction in unit steps of predetermined length, said second shift means including a ratchet toothed plate secured to said second movable clip, a manually operable reciprocable and rotatable spacing rod extending parallel to the drum axis for moving said second movable clip axially in a first direction, a check pawl whose position is fixed relative to said drum, said pawl co-operating with said ratchet plate teeth and means operatively connected to said spacing rod for lifting said check pawl from said ratchet teeth by rotation of the rod about its axis for moving said second movable clip in a second direction opposite to said first direction.

4. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip for securing an item master sheet to said drum, said first movable clip being located in a drum slot extending substantially the full axial length of said drum, first stepby-step shift means for shifting said first movable clip lengthwise of said drum in unit steps of predetermined length, a fixed position master clip parallel with and angularly spaced forwardly from said first movable clip in the direction of drum rotation, a second axially movable clip for securing a masking sheet, said second movable clip being located in said drum slot parallel with and angularly spaced forwardly from said first movable clip in the direction of drum rotation, and second stepby-step shift means for adjusting said second movable clip in either axial direction in unit steps of predetermined length, said second step-by-step shift means comprising a toothed ratchet plate secured to said second movable clip, a manually reciprocable and rotatable spacing rod extending parallel to the drum axis within said drum and a pair of pawls operable respectively by reciprocation and rotary movement of said spacing rod, said pawls each being mounted for movement in planes transverse to the spacing rod axis for engagement with and disengagement from the teeth of said ratchet plate.

5. A rotary hectographic copying machine according to claim 4, wherein said ratchet plate has two opposed series of rack teeth of equal pitch, one series being staggered with respect to the other, said two series of teeth being arranged respectively on opposite edges of an aperture in said ratchet plate, wherein a first one of said pair of pawls is constituted by a feed pawl carried by said spacing rod and wherein the second one of said pair of pawls is constituted by a check pawl mounted in a fixed position with respect to the drum, said two pawls each engaging with only a first one of said series of rack teeth during forward feed of said second movable clip by reciprocatory movement of said spacing rod and said check pawl being engaged alternately with a tooth on said first series of rack teeth and with the next adjacent tooth on the other of said series of rack teeth by oscillatory rotary movement of said spacing rod during the reverse feed of said second movable clip.

6. A rotary hectographic copying machine according to claim 5, which includes spring means for normally spring biasing each of said pawls into engagement withsaid first series of ratchet teeth and which includes lifting means for simultaneously lifting each of said pawls from said first series of ratchet teeth by rotation of said spacing rod.

7. A rotary hectographic copying machine according to claim 4 including clip opening means for said fixed position clip and said second movable clip, said opening means having a common manual control member whereby the two clips may be opened simultaneously irrespective of the axially adjusted position of second movable clip.

8. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip on said drum for securing an item master sheet therein, first shift means for shifting said first axially movable clip lengthwise of the drum, a fixed position clip on said drum for securing a heading master therein, said fixed position clip being parallel with but angularly spaced forwardly from said first movable clip in the direction of drum rotation and extending from one end of said drum for not more than half the axial length of the drum, a second axially movable clip on said drum for securing a masking sheet therein, said second movable clip being disposed in axial alignment with said fixed position clip, and second shift means for adjusting the axial position of said second movable clip, said second shift means comprising a clip spacing rod mounted within said drum and a ratchet and pawl coupling between said spacing rod and said second movable clip.

9. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotary printing drum, a first axially movable clip for securing an item master sheet on said drum, first shift means for shifting said first movable clip lengthwise of said drum, a fixed position clip on said drum for securing a heading master therein, said fixed position clip being parallel with but angularly spaced forwardly from said first movable clip in the direction of drum rotation and extending from one end of said drum for not more than half the axial length of said drum, a second axially movable clip on said drum for securing a masking sheet therein, said second movable clip being disposed in axial alignment with said fixed position clip, and common clip opening means for said fixed position clip and said second movable clip operable by a common manual control member.

10. In a rotary hectographic copying machine of the kind employing master sheets removably secured to a rotatable printing drum, a first axially movable clip for securing an item master sheet to said drum, said clip having a length substantially equal to half the length of the drum and being movable in a drum slot extending substantially the full axial length of said drum, first shift means for shifting said master clip lengthwise of the drum, a fixed position clip on said drum for securing a heading master therein, said fixed clip being parallel with but angnlarly spaced forwardly from said first movable clip in the direction of drum rotation and extending from one end of the drum for substantially half the length of the drum, a second axially movable clip axially aligned with said fixed position clip and of shorter length and step-by-step shift for moving said second movable clip axially in either direction with respect to said fixed position clip in unit steps of predetermined length.

11. A rotary hectographic copying machine as claimed in claim 10 in which said step-by-step shift means comprises a manually reciprocable and rotatable spacing rod extending parallel to the drum axis within said drum, and a ratchet and pawl coupling between said spacing rod and said second movable clip, said coupling including a feed pawl movable longitudinally of the drum by said spacing rod and mounted for movement in a plane at right-angles to said rod axis by rotary motion of said rod.

12. A rotary hectographic copying machine as claimed in claim 11 which includes spring means for urging said second movable clip in the direction opposite to that by which it is movable by said feed pawl and in which said step-by-step shift means includes an escapement mechanism operable by oscillatory rotary motion of said spacing rod for controlling movement of said second movable clip by said spring means.

13. A rotary hectographic copying machine as claimed in claim 12 which includes a first lever mechanism mounted on said drum for imparting reciprocatory motion to said spacing rod, a second lever mechanism mounted on said drum for imparting rotary motion to said spacing rod, each of said lever mechanisms including operating elements projecting at one end of said drum, a stationary framework for the machine, a manual control member mounted on said framework and movable in either of two different directions from an intermediate rest position and a rocking member mounted on said framework at a position adjacent said operating elements when said drum is in a predetermined rest position, said rocking member being arranged to engage and operate said first lever mechanism when said manual control member is moved in one direction and to engage and operate said second lever mechanism when said manual control member is moved in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,237,363 Ritzerfeld Apr. 8, 1941 2,440,635 Little et al. Apr. 27, 1948 2,604,847 Kvarnegard July 29, 1952 2,707,433 Roberts May 3, 1955 FOREIGN PATENTS 562,502 Great Britain July 5, 1944 113,374 Sweden Mar. 6, 1945