US2356160A

US2356160A - Printing machine drive

Info

Publication number: US2356160A
Application number: US369793A
Authority: US
Inventors: Albert J Horton
Original assignee: R Hoe and Co Inc
Current assignee: R Hoe and Co Inc
Priority date: 1940-12-12
Filing date: 1940-12-12
Publication date: 1944-08-22
Anticipated expiration: 1961-08-22

Description

Aug. 22, 1944. A. J. HORTON PRINTING MACHINE DRIVE Filed Dec. 12, 1940 5 Sheets-Sheet 1 NC m u Ev m; NJ n GT1 \w A 2 9 m -5 a 2 NT \mw RN am vm m mm ww NR R mu 6, v .m hm um 3 mm Nm 6 3 mm 2w N? mm mm 5 wm ma 2 9w Q mm 3 mm mm Nb m Nb mm v w mm @m mm INVENTOR Aug. 22, 1944.

A. J. HORTON PRINTING MACHINE DRIVE Filed Dec. 12, 1940 5 Sheets-Sheet 2 INVENTOR Aug. 22, 1944. A. J. HORTON PRINTING MACHINEDRIVE 3 Sheets- Sheet 3 Filed Dec. 12, 1940 INVENTOR Patented Aug. 22, 1944 PRINTING MACHINE DRIVE Albert J. Horton, White Plains, N. Y., assignor to R. Hoe & 00., Inc., New York, N. Y-., a corporation of NewYork Application December 12, 1940, Serial No. 369,793

21 Claims.

This invention relates to, printing machines and more particularly to an improved means for driving such machines that have a plurality of printing units.

In order to obtain maximum flexibility in the use of the large multiple unit printing machines at present used by publishers of newspapers and similar printed matter, it is considered advantageous to provide an individual motor drive for each printing unit.

This invention contemplates, as one of its objects, the provision for a multiple unit printing machine, of a, simplified and improved motor drive, whereby all'possible advantages of individual unit drive will be obtained.

Another object is to provide in an improved motor drive for a multiple unit printing machine wherein printing unitsand folders are geared to run in synchronism, electric motors equal in number to the printing units, and a gear reducer for driving the machine at slow speed by a, selected one or more of these motors.

It is also an object of this invention to provide a printing machine drive of improved construction and arrangement, that will be simple in construction, as well as convenient, practical, serviceable, and efficient in use.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts, and in the details of construction hereinafter described and claimed.

A practical embodiment of the invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a diagrammatic view showing a side elevation of a multiple unit printing machine embodying the features and principles of this invention;

Figure 2 is a plan view of the machine shown in Figure 1;

Figure 3 is a broken enlarged sectional view taken. on the line 3',3 of Figure 2 to show one of the unit driving motors;

Figure 4 is a sectional view taken on the line 4-4 of Figure 3;

Figure 5 is a schematic electrical diagram for two of the unit driving motors shown in Figures 1 and 2;

Figure 5A is a schematic electrical diagram similar to Figure 5, but showing connections for all of the driving motors shown in Figures 1 and Figure 6 illustrates a modified arrangement of gearing for a unit driving motor; and

Figure 7 is a schematic electrical diagram for the arrangement shown in Figure 6.

Referring now to the drawings wherein like reference numerals designate like parts throughout the several views, the numeral H (Figures 1 and 2) denotes generally, a printing machine frame upon Which has been assembled a plurality of printing units I2, l3, l4, l5, l6 and I1, each of which may include two plate cylinders l8 and [9 that cooperate with impression cylinders 2i and 22 respectively. As shown herein, a folder 23 is disposed between the units l3 and i4 and another folder 24 is disposed between the units [6 and I1. Thoseversed in the art will recognize this as a, quite usual arrangement Where printing units and folders are positioned in alignment, with provision for grouping any number of units and a folder to form a printing press of the capacity required to print a desired product.

Webs 25 are led upwardly from a suitable source of supply (not shown) to each of the units and after being printed thereby, are slit,associated, and fed toward'and into the folders 23 and. 24 by rollers 26, turner bars 21, and rollers 28 in the usual manner.

Each of the printing units and the folders are connected to a main line shaft 29 through vertical shafts 3| and 32 respectively, which are geared to the main line shaft 29 by means of

bevel gears

33, 34 and 35, 36 respectively. The shafts 3| may be connected to the cylinders of each unit through

bevel gears

31 and 38. In order to select the particular combination of printing units and folders desired for the product to be printed, the main line shaft 29 is adapted to be divided atintervals along its length by clutches 42, one between each of the adjacent printing units and one at each side of each folder. It is to be understood that, although not shown, the printing machines illustrated are provided with the usual inking devices for the plate cylinders, and the usual electrical control system including relays, magnetic switches arranged for push button operation, safety interlocking circuits and electrically operated brakes.

Electric motors

43, 44, 45, 46, 41 and 48 are provided, preferably equal in number to the printing units, and although more or fewer of these motors may be so connected, if conditions require it, two of them, 44 and 41 (Figures 1 and 2) are herein shown connected to the main line shaft 29 through speed reduction gearing and

bevel gears

64 and 65. The

other motors

43, 45, 46 and 48 are connected to the main line shaft 29 directly through bevel gears 49 and 5|.

The speed reduction gearing by which each of the

motors

44 and 4! may be connected to the line shaft 29 includes a gear pinion 52 secured on the motor shaft 53 and in mesh with a gear 54, secured on a jack shaft 55. A gear pinion 58 secured on the shaft 55 meshes with a cup-shaped gear 51 freely rotatable on a shaft 58, which is in alignment with the motor shaft 53, The gear has an overrunning clutch device operably associated therewith, which, in this instance, comprises a ratchet wheel 59 formed integral with and on the inner face of the cup-shaped gear 51. A disc 68 keyed to the shaft 58 carries a plurality of pawls 6| each of which is urged by a spring 82 into cooperating engagement with ratchet teeth 63 provided on the periphery of the wheel 59, to drive the shaft 58 in the same direction of rotation as that of the motor shaft 53. The shaft 58 is connected to the main line shaft 29 through

bevel gears

64 and 65.

In Figure 1, an arrangement of web leads is shown which provides for the grouping of printing units I2, I3 and I4 with folder 23, and units I5, I6 and II with folder 24, in which case the clutch in the line shaft 29 between units I4 and I5 would be disconnected. This arrangement provides two complete printing machines, each having three printing units. Obviously, a grouping including a greater or a lesser number of printing units with a folder may be arranged as desired.

Referring to the diagrams, Figures 5 and 5A it will be understood that these show a control arrangement in elementary form. It will be understood that a suitable control equipment for one of these printing machines includes many magnetic switches, pilot motors, resistances, relays, and electrical and mechanical interlocks which form no part of the present invention. A complete diagram of them would be very complicated and as it is not necessary to an understanding of the invention, it is omitted. The diagrams shown in Figures 5 and 5A however, show the general operation and sequence performed by a controller that would include the various elements hereinbefore mentioned and are a more convenient means of explaining the invention in a manner understandable to those versed in the art.

For the sake of clearness, electrical connections (in schematic form) are shown in Figure 5, for a group including printing units I6 and I! with folder 24. When it is desired to run this group at slow speed, as for instance, for threading a web 25 through the machine, the motor 4! which has a speed reduction gearing associated therewith, is started. This is accomplished by moving a contact shoe support, 56 from left to right causing a contact shoe 6! to engage the first of a plurality of contacts 68 connected to sections 69 of a rheostat in series with the armature of the motor. As the contact shoe 51 is advanced along the contacts 68, the motor is gradually brought up to speed, the printing machine meanwhile being operated through gears 52-54, shaft 55, gears 565I, ratchet wheel 59, pawls BI, and the shaft 58 which carries the bevel gear 64 in mesh with the gear 65 on the line shaft 29. When so driven, the press will operate at a relatively slow speed.

When it is desired to accelerate the machine to a speed suitable for printing, the contact shoe support 86 is moved further to the right, so that the contact shoe 61 passes beyond the contacts 68, onto the contact bar II which is connected to one terminal of one part I2 of a magnetic clutch secured on the shaft 53. The other terminal of the clutch part is connected to line wire 62 and it is thus energized and clutched to its cooperating clutch part I3, secured on the shaft 58. The circuit of the motor 4! has meanwhile been broken by the contact shoe 61 leaving the last contact 68, but it is re-established by a contact shoe I4 (also carried by the contact shoe support 65), when the shoe I4 engages the first of the contacts 68. The motor is thus again energized, but with all of the rheostat sections 69 in circuit. The effect of this is to again connect the motor for its operation at slow speed when the magnetic clutch is energized. By continued movement of the support 66, the motor 41 may again be brought up to speed by cutting out the resistance sections 69, and as hereinafter explained the press can be accelerated to full speed.

As shown, the contact shoes 61 and I4 are connected to a line wire LI through a contact bar 15, on which the support 66 slides, and the motor field i6 and armature 1! are connected-to the line wire L2 through switches I8. Means are provided whereby as soon as the magnetic clutch parts l2 and I3 are engaged, the motor 48 which is geared directly to the main line shaft 29 is also started to assist the motor 4! in carrying the load when the printing machine is operating at full speed. When the shoe I4 engages the first one of the contacts 68, another shoe I8, is ar ranged to contact the first one of a plurality of contacts 79 connected to rheostat sections 80 in circuit with the armature BI of the motor 48, which is connected to the line wire L2 by switches similarly to motor 41. When operating at the higher machine speeds, the motor 41 is directly geared to the main line shaft 29 and the speed reducing gearing is ineffective, due to the action of the overrunning clutch mechanism 59, 68, 6|.

From the foregoing, it will be seen, that with driving equipment made in accordance with the invention as herein disclosed, a group of two printing units and a folder are provided with connecting shafts and gears whereby they are operated in synchronism. Two motors (first and second) are provided. The first motor has a speed reducing gear mechanism with an overrunning clutch device, and a magnetic clutch with suitable control means. The first motor with its speed reducing gear is employed to start and operate the machine at slow speed and when it is desired to operate at printing speed, the first motor is disconnected from its source of current, and the magnetic clutch associated with it, is energized. Simultaneously, with the energization of the clutch, the speed reducing gear becomes ineffective, and the first and second motors are both energized, and act inparallel to accelerate the machine to, and operate it at, printing speed.

It will be seen that the first motor is first started and is accelerated to full speed while driving the machine through th reducing gear. At this point, the first motor is deenergized for a short interval and the magnetic clutch is engaged and simultaneously the motor is again energized, but connected in series with resistance for slow speed operation. While this changeover is being made, the pawls 6| start to run ahead of the ratchet wheel 59 and the teeth 63 push the pawls outwardly. The pawls ISI are then held out of engagement with the teeth 63 by centrifugal force. On the engagement of the magnetic clutch, the clutch part I2 connected to the motor, is rotating at relatively high speed, while the 1 part 13, which is running in synchroni-sm. with the line shaft of the press, is rotating at relatively slow speed. .As the two clutch members are engaged, themotor 41 is deceleratedtothe same can be operated by both motorsin parallel, the springs 62 overcome the centrifugal force acting on'the pawls BI, .and force them into engagement with the teeth 63 of the ratchet wheel'59. Be-' cause the magnetic clutch is released, the motor;

41 is accelerated and rotates the gear 51 at a speed equal to that of the ratchet wheel, the pawls 6| take the load and furtherdeceleration' of the machine is controlled by the motor 41 acting through the speed reducing gearing.

The control equipment for motors 4'5 and 46 may be arranged similarly to that shown for motor 48. Such an arrangement is shown in Figure 5A, at the right hand portion of which, the

mo tors

41, 48, 46 and 45 are shown grouped together and controlled by the contact shoes 61 and 14 for motor 41, and 18, 18a and 182) respectively formotors 48, 46 and 45. The contact shoe support 66a which corresponds with contact shoesupport 66 of Figure 5, carries

shoes

61, 14 and 18, and in addition, shoes 18a and 18b. These additional contact shoes engage rheostat contacts 19a and 19b respectively at the same time the contact 18 engages the rheostat contacts 19. A grouping of the motors for four printing units and a folder may thus be arranged, and obviously if only three units are required, the switch a that controls the circuit to the motor 45 may be opened and that motor and its printing unit will then be silenced.

As a further extension of the grouping arrangement, a combination of six printing units and a folder may be controlled by connecting

motors

43 and 44 in parallel with

motors

45, 46, 41 and 48. The connections for such operation of

motors

43 and 44 being shown at the left in Figure 5A. In this arrangement, two motors having reducing gears, i. e., motors 44 and 41, are used for starting and running the machine at slow speeds. These motors are controlled by control mechanism corresponding to that previously described, which includes a contact shoe support 66b, connected to the support 66a by means of a removable connecting link 660, that is shown in dotted lines. The support 66b carries contact shoes 61a, 14a and 180, which correspend with the contact shoes 61, 14 and 18 car ried by the support 66a. The supports 66a and 66b being linked together, are moved simultaneously, and when moved toward the right, they will start and accelerate the motors 44 and 41 when the contact shoes 61 and 61a engage and move along the contacts 68 and 68a respectively. Further movement of the shoes 61 and 61a beyond these contacts and onto the contact bars 1 I, decelerates the motors 44 and 41 by establishing simultaneously, slow speed connections through the shoes 14 and 14a, and energizes the magnetic clutches 12. At this time the

motors

43, 45, 46 and 48 also are energized by the contact shoes 18, 18a, 18b and 180 engaging con-v Thereafter, all six,

tacts 19, 19a, 19b and 190. motors shown on Figure 5A will operate inparis reallel to: drive the machine. Obviously by removing'the connecting link 660 the

motors

43 and 44 may be operated as onegroup, and

motors

45, 46, 41 and '48 operated independently as another *lnthearrangement disclosed in Figures 6 and 7,"the motor 82, corresponding to the motor 41 9Z,which, in turn, is in mesh with a gear 93 se-- cured-tothe main line shaft 29., Through this speed reduction gearing the machine is operated at slow, or web threading speed. When it is desired to run the machine at higher speed, the shoe 94 connecting the magnetic clutch 83 with the line -wire- LI breaks its engagement with a bar- 95 connected to one termina1 of the clutch 83, the other terminal of which is connected to L2, and a shoe 96 engages a bar 91 connected to one terminal 'ofth clutch 84 to energize it through a connection extending from its other terminal to L2. When the clutch 84 is energized, the motor shaft 9| is connected to a pinion 98 through ashaft 99 to which it is secured, and as the pinion 98 is in mesh with a gear I00 secured on the main line shaft 29, the motor- 32 is thus geared directly to the shaft. As

" in the previously described form, the other driving motors are connected to the main line shaft 29 and are energized in parallel relation, when the clutch 84 is energized by the engagement of the shoe 96, this being accomplished by contacts I0! that areengaged by the shoe 94 after it leaves the bar 95. a

In other respects, the motor 82 is controlled as hereinbefore described in respect to the motor 41.- The contact 96-is carried on a support I05 andis adapted to engage contacts I06 to gradually accelerate the motor 82 for the slower machine speed range by cutting out rheostat sections I01 connected to the armature I03. After the shoe 96 engages the bar 91 another shoe I08 carried by the support I05, engages the contacts I06 to-again accelerate the motor 82 while any additional motors then connected are being accelerated as above. described. The shoes 94, 96 and I08 are connected to the support I05 and slide on a bar I09 which is connected to the line wireLI. v

Infapplicants preferred constructions, as hereinshown and described, magnetically operated clutches are employed, but it will be understood thatother types may be substituted if preferred. Suitable mechanical clutches are available that may be operated electrically, or manually oper the firstone (or ones), for operating the machine at high speed.

It will be ,understood that the inventionmay be embodied in other specific forms without departing from the spirit or essential attributes thereof. and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, and it will be further understood that each and every novel feature and combination present in or possessed by, the mechanism herein disclosed forms a part of the invention included in this application.

What I claim is:

1. In a printing machine including a plurality of printing units and a folder geared to run in synchronism, motors equal in number to the printing units, connections between the motors and the machine for operating all of the motors together to drive the machine at printing speed, a speed reducing gear associated with one of the motors for driving the machine at slow speed, and control means operable to cause the machine to be driven through the speed reducer by the said one motor, and alternatively, through the said connections by all of the motors.

2. In a printing machine having a plurality of printing units and a folder connected by shafting to run in synchronism, the shafting being divided into first and second sections connected by clutches, a first section drivingly connected to the folder only, a second section drivingly connected to each printing unit, a motor connected to each second shaft section, a speed reducing gearing between one of the second sections and one of the motors, and means to selectively con meet the said one second section to the said one motor directly, and alternatively through the speed reducing gearing, and to control the said one motorto operate the machine at slow speed, then to decelerate the said one motor, and then to control all of the motors to operate the machine at high speed.

3. In a printing machine having a plurality of printing units and a folder connected to a common shaft to run in synchronism, the common shaft being divided into sections connected by clutches, the folder drivingly connected to one of the shaft sections, each printing unit being connected to a shaft section, a motor connected to each of the shaft sections connected to a printing unit, a speed reducing gearing between one of the motors and a shaft section connected to one of the printing units, and means to drive the last mentioned shaft section by the said one mot-or directly, and alternatively through the speed reducing gearing, including a controller arranged to start and accelerate the said one motor through a range of speed while said shaft section is being driven through the said speed reducing gearing, and then to again accelerate the said one motor through the said range of speed while the said shaft section is being driven directly.

4. In a printing machine having printing units and a folder connected to a common drive shaft to run in synchronism, motors for driving the common shaft, a speed reduction gearing between one of the motors and the common shaft, a first clutch associated with the gearing whereby the shaft may be driven at slow speed, a second clutch to connect the said one motor directly to drive the shaft whereby it may be driven at high speed. control means for the said one motor to first accelerate the speed of the said one motor while the first clutch is operative, to then decelerate the said one motor, and to actuate the second clutch todirectly connect the said one motor to the common shaft and to again accelerate the said one motor to drive the shaft at high speed.

5. In a printing machine, a plurality of printing units and a folder, a common shaft to which the units and the folder are drivingly connected, speed reducing gearing, an overrunning clutch, motors equal in number to the printing units and adapted to operate in parallel to drive the common shaft .at printing speed, a magnetic clutch to directly connect one of the motors to the common shaft when it is to be driven at printing speed, the said one motor being drivingly connected to the common shaft through the speed reducing gearing by the overrunning clutch to drive it at slow speed when the magnetic clutch is released, and control means for the said one motor to accelerate its speed and including means to energize the magnetic clutch to directly connect the said one motor to the common shaft and to again accelerate its speed and also start and accelerate the other motors.

6. In a printing machine, a plurality of printing units and a folder, a common shaft to which the units and the folder are drivingly connected, speed reducing gears, motors equal in number to the printing units, a magnetic clutch adapted to directly connect one of the motors to the common shaft, the said one motor being drivingly connected to the common shaft through the speed reducing gears by an overrunning clutch, control means to start and accelerate the last mentioned motor, and then to energize the magnetic clutch to directly connect the motor to the common shaft and to again accelerate the motor, and means to operate the other motors in synchronism with the said one motor after it is connected to the common shaft by the magnetic clutch.

7 In a printing machine having printing units and a folder connected to a common drive shaft, first and second motors for driving the common shaft, speed reduction gearing between the first motor and the common shaft whereby the shaft may be driven at slow speed, a first electrically operated clutch for connecting the first motor to the common shaft through the speed reduction gearing, a second electrically operated clutch for connecting the first motor to the common shaft without driving it through the speed reduction gearing, and control means to energize and accelerate the first motor, and then deenergize the first clutch, decelerate the first motor, energize the second clutch, and energize and then accelerate the first and second motors.

8. In a printing machine having printing units and a folder connected to a common drive shaft, motors equal in number to the number of printing units for driving the common shaft, a speed reduction gearing between one of the motors and the common shaft whereby the shaft may be driven at slow speed, an electrically operated clutch for connecting the said one motor to the common shaft through the speed reduction gearing, an electrically operated clutch for connecting the said one motor to the common shaft without driving it through the speed reduction gearing, and electrical control means to energize the said clutches in sequence, and to accelerate the said one motor after each clutch has been energized.

9. In a printing machine having printing units and a folder connected to a common drive shaft to run in synchronism, a motor for each printing unit, each motor having a driving connection with the shaft, speed reduction gearing between one of the motors and its driving connection, a.

-- a secondclutch means to connect the-said one motor directly to its driving connection, and control means for the motors and the clutch means,

whereby the shaft may bedriven at slow speed byth'esaid. one motor and. at highspeedby all of the motors.

.10. In. a printing machine having rintin units and a folder connected to a common drive shaft to run in synchronism, a motor for each printing unit, each motor having a driving con-z,

nection'with the shaft for .driving the machine troller operable to energize the said one motor to operate the machine at slow speed, to accelerate the said one motor and thereby. accelerate the machine, to then decelerate the said one motor.

and-start the other. motors, to actuate the clutch means, and to again energize the said one motor, and further accelerateiand drive the machine at high speed by all of the motors.

11. In a printing machine having printing units and a folder connected to a common drive shaft to run in synchronism, a motor for each printing unit, each motor having a driving connection with the shaft for driving the machine at high speed, speed reduction gearing between one of the motors and its driving connection, whereby the shaft may be driven at a slow speed, clutch means effective to connect the said one motor and its driving connection, and a controller including a rheostat for controlling the said one motor to drive the press at slow speed, the said rheostat being removed from circuit to accelerate the said one motor, then reinserted in circuit, and then again out out of circuit to again accelerate the said one motor to assist in drivin the machine through a direct connection.

12. In a printing machine having a plurality of machine units connected to a common drive shaft to be driven in synchronism, a motor for each unit, a first one of the motors having a high speed driving connection with the shaft, speed reduction gearing between a second one of the motors and the shaft, clutch means to disconnect the second motor from the gearing and establish a high speed driving connection with the shaft, and control means for the motors and the clutch means, whereby the shaft may be driven at slow speed by the said second one of the motors through the speed reduction gearing and at high speed by both motors operating together.

13. In a printing machine having a plurality of machine units connected to a common drive shaft to be driven in synchronism, a motor for each unit, a first one of the motors having a high speed driving connection with the shaft, speed reduction gearing between a second one of the motors and the shaft, clutch means to disconnect the second motor from the gearing and establish a high speed driving connection with the shaft, and a controller operable to energize the said second motor to drive the machine at slow speed, to accelerate the said second motor and thereby accelerate the machine, to then decelerate the said second motor and start the said first motor, to actuate the clutch means, and to again energize the said second motor, and further accelerate and drive the machine at high speed by both motors.

14. In a printing machine having printing .motors, and control meansto start and accelunits and a folder connected toa-commondrive shaft to run in synchronism, motors for-driving the common shaft at a high speed, speed reduction gearing connecting one of the motors and the common shaft whereby the shaft. may be driven at a slow speed by the said one motor alone, an overrunning clutch associatedwiththe gearing, other means tocchnect thesaid one motor to the common shaft, whereby the shaft may be driven at a high speed by all of the crate the-saidone motor to normal speed, and

' then to energize the saidother means to directly connect the motor tothe common drive shaft and to again accelerate the said one motor with the other motors connected in parallel.

15. In a printing machine, a plurality'of printing units, a folder disposed between adjacent printing units, common driven means connecting the said units and folders'to drive them in synchronism, motors equal in. number to the number of printing units, control means, ar-

ranged to operate all of the motors together to drive the common driven means at printing speed, speed reducing gearing associated with one of the motors, and means included in the control means to selectively connect the common driven means directly to the said one motor and alternatively through the speed reducing gearing.

16. In a printing machine having printing units and a folder connected to a common drive shaft to run in synchronism, motors for driving the common shaft at printing speed, speed reduction gearing between one of the motors and the common shaft whereby the shaft may be driven at slow speed by the said one motor alone, an overrunning clutch between the gearing and the shaft, a magnetic clutch to connect the said one motor directly to the common shaft, and control means to start and accelerate the said one motor through a range of speed, and then to energize the said magnetic clutch to directly connect the said one motor to the common drive shaft and to again accelerate the said one motor through the said range of speed in synchronism with the other motors.

17. In a printing machine, a plurality of printing units and a folder, a common shaft to which the units and the folder are drivingly connected, motors equal in number to the printing units and adapted to operate in parallel to drive the common shaft at printing speed, an electrically actuated clutch to directly connect a first one of the motors to the common shaft when it is to be driven at printing speed, speed reducing gearing and an overrunning clutch associated therewith and connected between the first motor and the common shaft to drive it when the machine is to be driven at slow speed, and a controller to control the first motor and the electrically actuated clutch, to operate the first motor and drive the shaft at slow speed through the speed reducing earing, to decelerate the first motor, to actuate the clutch, and to control all of the motors to drive the shaft at printing speed.

18. In a printing machine having printing units and a folder connected to a common drive shaft, first and second motors for driving the common shaft at printing speed, speed reduction gears between the first motor and the common shaft, whereby the shaft may be driven at slow speed by the motor alone, a clutch for connecting the first motor to the common shaft through the speed reduction gears, a clutch for connecting the first motor to the common shaft without driving it through the speed reduction gears, and control means to first energize and accelerate the first motor, then reduce its torque, and then accelerate the first and second motors in synchronism.

19. In a printing machine including a plurality of printing units and a folder geared to run in synchronism, motors equal in number to the printing units, connections between the motors and the machine for operating all of the motors together to drive the machine at printing speed, a speed reducing gear associated with one of the motors for driving the machine at slow speed, and control means operable to cause the machine to be driven through the speed reducer by the said one motor while running at any speed within its range, and alternatively, to be driven through the said connections by all of the motors.

20. In a printing machine including a plurality of printing units and a folder geared to run in synchronism, a plurality of motors, connections between the motors and the machine for operating all of the motors together to drive the machine, a speed reducer gear associated with one of the motors for driving the machine at slow speed, and a control means arranged to energize the said one motor to drive the machine at slow speed, then to accelerate the said one motor, then to reduce the power of the said one motor, and then to energize and accelerate the other motors and again accelerate the said one motor.

21. In a printing machine including a plurality of printing units and a folder geared to run in synchronism, a plurality of motors, connections between the motors and the machine for operating all of the motors together to drive the machine, a speed reducer gear associated with one of the said motors for driving the machine at slow speed, and a control means arranged to cause the said one motor to drive the machine at slow speed, then to reduce the power of the said one motor and energize the other motors and accelerate the said plurality of motors in synchronism.

ALBERT J. HORTON.