US2315459A - Textile printing apparatus - Google Patents

Description

March 30, 1943.

s. a. STAFFORD 2 9 TEXTILE PRINTING APPARATUS Filed Odt. 24, 1,940

In In Zhwentor 515 62672 B. S/dfford 1739 Q a ttorneg Patented Mar. 30, 1943 TEXTILE PRINTING APPARATUS Stephen B. Stafford, Oxford, Mass, assignor to Rice Barton Corporation, a corporation of I Massachusetts Application October 24, 1940, Serial No. 362,502

4 Claims.

This invention relates to textile printing apparatus and particularly to apparatus which is arranged for feeding fabric to the printing machine continuously and under proper tension for the printing operation.

Fabric to be printed for use as dress goods and the like may vary somewhat in ts composition, texture and width. Hence, as the fabric travels to the printing roll it may wander laterally and not maintain an alignment with the edges of the engraved surface of the roll. It has, therefore, been customary for the engraved portion of the printing roll to be made somewhat narrower than thewidth of the fabric to be printed and thereby leave an unprinted selvedge on the fabric; whereas in some cases it is desirable to print to the edge of the fabric. To this end, the apparatus should be so constructed that the fabric tracks or stays fed continuously under'a uniform tension and at a controlled width. In the preferred construction, fabric is fed from a succession of supply rolls through a scray or other suitable accumu lator and then through a tentering device arranged to stretch the fabric to a uniform width and finally through a tensioning device to the printing machine. The tensioning device may comprise an electrical brake or other suitable in alignment with the engraved portion of the printing roll. This involves bringing the fabric to a uniform width just prior to its entry to the printing zone. It, moreover, is desirable that the fabric be fed to the printing zone under a uniform tension, but owing to the variations in the texture of the cloth special provisions must be made to provide this uniform tension. It has been proposed to pass the cloth over a dancer roller mounted near the printing roll and to provide tension in the cloth by means of springs which support the dancer roll. These springs tend-to vibrate under the impulses imparted by the rapidly moving fabric and so cause the roll to dance and thus vary the tension on the fabric and defeat the purpose of the device. It is therefore desirable to employ a construction which positively holds the fabric under a uniform tension and prevents any material variation in that tension as the fabric enters the printing zone.

The primary object of this invention is to overcome these various problems and to provide a textile printing apparatus which will cause the fabric to be fed properly to the printing zone.

A further object is to provide an apparatus which insures that the fabric to be printed is held at a uniform width under a uniform tension as it enters the printing zone.

Another object is to provide an apparatus whereby fabric may be fed continuously to the printing zone from a succession of supply rolls and the printing conditions properly maintained withoutstopping the machine for removal of a supply roll. Further objects will be apparent in the following disclosure.

In accordance with this invention, I have provided a printing machine to which the fabric is mechanism which is so constructed and arranged that the fabric is held between it and the printing roll under a substantially uniform tension, both laterally and longitudinally thereof.

Referring to the drawings which show a preferred embodiment of this invention:

Fig. 1 is a somewhat diagrammatic elevational view of an apparatus embodying this invention;

Fig. 2 is a vertical elevation of the tentering frame;

Fig. 3 is an end elevation of the same and shows a simplified wiring for its control; and

Fig. 4 is a wiring diagram showing the speed synchronization of the printing roll and the tensioning device.

The printing machine is here illustrated, for the sake of simplicity of illustration, as comprising a single printing roll Ill, but this type of machine may be provided with a plurality of rolls for the purpose of printing difierent colors or portions of a design pattern on the fabric. Each printing roll is suitably mounted in accordance with the standard practice on a mandrel I l supported in half bearings 12 carried on slide blocks l3 adjusted by means of the screw and handwheel l4 toward and from the backing cylinder l5, so that the fabric l6 may be held under proper pressure as it passes through the printing zone between the backing cylinder and the printing roll. The backing cylinder is customarily mounted for free rotation under the frictional drive of the printing roll. Each printing roll is in turn driven by means of a gear i8 connected to'the printing roll mandrel which meshes with the large gear wheel I9 axially aligned with the cylinder IS. The large gear is driven by a gear 20 which in turn is driven through a chain 2| and sprocket 22. The latter is mounted on the axle of and driven by a suitable electric motor 24, which is designated as P. M. on the wiring diagram. A roll 30 of the fabric to be printed may be removably mounted on a portion of the framework of the machine.

In order that the fabric may be fed continuously to the printing zone, provision is made which permits the rear end of the fabric on that roll to be sewed to the leading end of another roll without stopping the printer. A suitable apparatus as shown comprises a scray arranged to accumulate a supply of fabric or cloth as received from the roll and to feed the same forward to the printer as needed. This scray comprises an endless belt .32 of suitable construction and which may be, for example, made of a rubber strip reinforced by cross strips of wood. This scray belt is arranged as illustrated to support a considerable amount of the fabric as it is being accumulated and fed forward. Various constructional features may be employed for the purpose. As illustrated, the endless scray belt 32 passes over two upper rollers 34 and 35 and around two lower rollers 36 and 31 which are suitably mounted on the machine framework. The roller 35 is driven by means of a sprocket 3i fixed thereto and connected by a chain to a small sprocket 35, and the latter is in turn driven by another sprocket 44 secured thereto and connected by a chain 41 to a-sprocket 3.8 keyed on the shaft of the motor 40. A chain 42 passes from the sprocket 43, which isconnected to rotate with the roller 35, and it drives another sprocket 45 affixed to rotate the roller 34. These parts are so arranged as to drive the endless scray belt at a very slow speed relative to the speed of the fabric passing therethrough. The

cloth is drawn from the supply roll into the scray belt by means of a pair of power driven rollers 48 and 49, the upper roller being adjustable toward and from the lower one to permit stopping the end feed of the fabric when desired. These two rolls are positively rotated by means of a further chain 50 driven by a sprocket 5| affixed to rotate with the sprocket 39 and be driven by the motor 40. The sprocket 5| is slightly larger than the gear 4| on the shaft of the roll 49 so that the rollers 48 and 49, which feed the fabric to the scray, travel faster than the rollers 54 and 55 which remove the fabric from the scray. Hence the fabric will accumulate on the traveling scray belt as it passes forward to the printing zone. A suitable folding apparatus (not shown) may be employed to fold the fabric into loops on the scray belt as it is drawn from the supply roll.

The fabric that is positively withdrawn from the scray by the rollers 54 and 55 is led to a tentering frame which is arranged to stretch the fabric and to guide the same into the printing zone. The tentering apparatus may be of any suitable standard construction and need not be described in detail. It is simply illustrated in Figs. 2 and 3 as comprising two endless chains and BI which are arranged to grip the entering fabric and stretch the same as the fabric and chains travel together toward the printing zone. These endless chains are arranged to travel at an angle so as to provide a gradually widening throat, and this angle may be adiustedif desired. Each of the two chains is arranged to pass around a pair of wheels or pulleys G2 and 63. The wheels 52 are mounted on short vertical shafts 64 suitably supported on the framework, and the other wheels 63 are mounted on longer shafts 65, each of which carries at its lower end the worm gear 66. Suitable bearings are provided for mounting and supporting the various parts. These two worm gears (Fig. 3) are in turn driven by the left and right hand worms G8 which are carried on a drive shaft 59, and this drive shaft is driven by a suitable electric motor 10.

The endless chains BI and 62 comprise a series of clamps arranged to grip the fabric as it enters the tentering frame. These clamps may be sultably constructed and, as illustrated somewhat diagrammatically, may comprise U-shaped clips 12 on which are pivotally mounted the fingers 13, the lower ends of which are weighted and arranged to lie normally in contact with the lower supporting portion of the clip or the fabric lying thereon. A circular cam 15 is arranged in axial alignment with each of the shafts 54 and 65 and is of such size that as the upwardly projecting finger 13 of the locking clips approach the fabric receiving end of the frame, they are tipped by the cam so that the oncoming fabric may enter into position beneath the locking fingers 13 and then be held thereby when the fingers fall into position after they have passed beyond the cam. Similarly, at the exit end of the frame, the fingers are pushed outwardly to release the fabric and permit it to travel to the printing zone. These constructional features may be suitably constructed in accordance with standard apparatus on the market. The two endless fabric stretching belts are fixed at or adjusted to such an angle that the fabricis automatically stretched as it passes through this tentering frame to a width which is determined by the distance between the opposed clamping fingers of the two belts.

The tentering frame may also m moved laterally in order to track or align the fabric with the engraved surface of the printing roll. This is accomplished by any suitable construction, such as that illustrated in Figs. 2 and 3. This comprises two screws threaded into two blocks 8| which are mounted to move laterally the table 82 supporting the endless tenter frame belts and their driving mechanism. The ends of the screw 80 are suitably mounted in hearings on the framework 84, and one end of each screw is connected to a worm gear 85 which is driven by a worm 86. These two worms 85 are rotated in the same direction by an electric motor 88 having its shaft suitably connected thereto. The motor 88 is of the reversible type so that the tenter frame may be moved to either side depending upon the direction of rotation of the motor.

A suitable mechanical feeler or an optical control mechanism may be employed to control the operation of the motor 85 and cause the fabric to be adjusted automatically into a desired track. This control mechanism may comprise a pair of pivoted feelers engaging the opposite edges of the traveling cloth and connected to electrical switches which control the motor so that if the cloth moves toward the left, the tenter frame will be moved toward the right and vice versa, and thereby insure a proper tracking of the cloth. This control mechanism may be made of any suitable construction as is understood by one skilled in the art. A simplified wiring diagram is shown in Fig. 3 of the drawings. The apparatus comprises photoelectric tubes A located at the point where the fabric passes into the printing zone. Beams of light are passed vertically to these tubes and serve to activate them and lower their resistance to an electric current. This occurs when the moving fabric does not out off the beam. The current passes through one of two relay coils B in a suitable electric circuit which are connected to actuate the two way reversing switch C. The latter is held in a central inoperative position by springs D when the light beam strikes both of the tubes A and the pull of their relay cores B on the switch is equal in the opposite directions. If the fabric edge cuts off the light to one tube A, then the associated relay core is not activated and the other core pulls the switch over into one of its contact positions, where the current rotates the motor 88 in such a direction as to move the fabric far enough laterally to permit the beam of light to strike the tube again and cause the fabric to travel in the new path. The parts are so located that a slight deviation of the fabric from proper registration or alignment with the printing roll will cause one or the other relay to operate and move the fabric laterally as required. The tentering frame may, if desired, be arranged in a fixed position without provision for lateral movement of the fabric. It

' is preferably located close to the printer so that the fabric will not wander materially as it travels between the two parts.

The positively driven printing roll and the associated backing cylinder draw the cloth into the printing zone, and the cloth is preferably smoothed out by a pair of spreaders 90 and Si having opposed helical threads and made. of standard construction which aresuitablyarranged and monuted on the printing machine framework. The oppositely directed helical threads are so arranged that as the fabric passes thereover, it is smoothed out and spread toward its outer edges. The fabric has been stretched laterally by the tenter frame and the spreaders are merely supplementary to insure that no change occurs in the lateral stretch of the cloth.

A primary feature of this invention involves coordinating the mechanisms which move the fabric and providing the proper tension on the cloth as it enters the printing zone. This tension may be applied to the fabric by means of a tensioning device which, in the embodiment illustrated, comprises an electrical brake; but various types of mechanical or hydraulic devices may be employed for the purpose. The device illustrated comprises a pair of rolls 92 and 93 which grip the fabric therebetween. These rollers are mounted on parallel axes and are geared together and arranged to rotate at the same speed. They are connected by a chain and sprocket with a direct current motor 96 suitably mounted or. the framework for driving them. The motor 96, designated T. M. on the wiring diagram of Fig. 4, is a constant speed electric motor which is overdriven by the fabric at a higher rate than its normal speed so that it is forced to act as an electric generator and thus resist the forward movement of the cloth. Various types of electric motor-and wiring arrangements may be employed as will be readily understood by one skilled in the electrical art. This electric motor is preferably adapted to run at a constant speed with a constant load and to vary in torque directly with variations in the current input. The motor may be constructed and connected so that it tends to drive the fabric at a rate of, say, 75% of that at which the printing machine draws the fabric forward. The motor initially aids in moving the fabric while the machine is being started up; but when the fabric is moving at full speed, the motor is overdriven and becomes a generator of electricity and so applies a counter force which resists the forward movement of the cloth. The faster the cloth moves, the greater is this counter torque applied by the motor generator to increase the tension on the cloth.

The tension motor has the same general characteristics as another motor with which it is connected in parallel in a constant voltage D. C.

circuit, and this other motor is preferably the printing machine driving motor. -A suitable wiring diagram for these two motors is shown in Fig. 4, and the arrangement of the apparatus will be apparent by reference to the legend on the diagram. The direct current generator G. D. C. in the variable voltage armature circuit is driven by a suitable constant speed motor. -This serves to drive the direct current printer motor P. M. and the direct current tension motor T. M. at constant speeds when the current is held constant. An exciter EX develops a direct current of constant amperage for the shunt fields which control the speeds of the two motors and the direct current generator. A constant current regulator of standard construction which mechanically interconnects the armature circuit and the shunt field circuit serves to maintain a constant current in theshunt field circuit, and this may be further regulated as desired by the variable rheostat R. Suitable mechanism may be employed to start and stop the motors as illustrated in the diagram, and this may be of any standard construction and need not be here described. By adjusting the rheostat R, the shunt field of the tension motor may be varied to change the speed of that motor and thereby vary the back pressure or the longitudinal tension on the fabric. After this adjustment has been made, then that tension will remain uniform because of the constant current developed in the circuit. That is, if the speed of the printer motor remains uniform, then the'current in the shunt field remains uniform and the tension on the fabric does not change. This construction may be as shown in my prior application Serial No. 300,433 filed October 20, 1939, and various detailsof the mechanisms and constructional features there illustrated may be also incorporated in this machine, if desired.

It is also desirable to hold the cloth under longitudinal tension as it enters the tentering frame, and to this end I employ mechanism which will insure that the motor which drives the feed rollers for removing the fabric from the scray will have its speed controlled to maintain tension on the fabric. The preferred construction comprises a dancer roll 98 (Fig. 1) which is mounted on the end of a swinging arm 99 which is one arm of a bell crank lever. The otherarm I00 is the control lever of a rheostat, illustrated diagrammatically at ml. The fabric it in passing from the rolls Stand 55 goes around an idler roll I02 and then around the dancer roll 98 and over an idler roll I03 and a further roll I04 which is located to align the cloth with the tentering frame. The rheostat |0I and associated electrical mechanisms are so arranged that when the dancer roll 98 moves down under its own weight, as permitted by a too rapid feed of the fabric by the rolls 54 and '55, it will move the rheostat control arm in such a direction as to increase the current to the shunt field of the motor 40 and thereby cause the motor to slow down slightly. Likewise, when the fabric is fed too slowly by rolls 54 and 55, the rheostat arm will move'up and speed up the motor 40 and cause it to feed the fabric forward at a slightly greater rate. It will, therefore, be seen that the printer motor 24 or P. M. gives a reference speed for the other motors. The electrical brake resists the forward movement of the fabric to the printer just enough to maintain it under a suitable tension, and the tension between the electrical brake and the scray is maintained by the dancer roll 88 which controls the speed of the motor 40.

The construction as above described may be employed without the use of a back gray cloth, which is customarily employed to receive the ink from the printing roll where it overlaps the fabric. Since the alignment or tracking of the fabric with the printing roll may be carefully regulated in accordance with the above description,

then that back gray cloth need not be employed.

the fabric may be continued without interrup tion as a succession of fabric rolls 3!! is supplied to the machine. The fabric is fed forward at a continuous and substantially uniform rate by the feed rolls 54 and 55, which withdraw the fabric from the scray at a rate determined by the requirements of the tentering frame. This rate is governed by the dancer roll 98 and the rheostat control NH. The fabric travels through the tentering apparatus and is there stretched to a predetermined width, and this stretching serves to vary the tension on the cloth. The rate of feed of the fabric through the tentering zone is synchronized with the fabric movement into the printer by suitable mechanism. If desired, the printer motor may be employed to pull the fabric through the tentering zone. After the fabric leaves the tentering frame, it is passed directly to the printer under a controlled tension, as provided by the electrical brake rolls 82-93 which is operated automatically in accordance with the speed of the printer rolls ID. This tension is invariable, once it has been adjusted by means of the rheostat R f Fig. 4). There are no resilient parts to vibrate .and the tension is not affected by changing conditions in the texture of the fabric. The driving motors supply the fabric as needed and the tension motor holds back on the moving cloth with a uniform resistance. Hence, the tension is uniform. If a given printer roll I0 is removed from the machine and replaced by another roll of a greater or lesser.

diameter, the electrical brake may be regulated to function in accordance with the speed requirements of the printing press and cause the cloth to be delivered thereto under a substantially uniform and desired regulatable tension. If the printing press is speeded up and calls for more fabric, this demand is communicated through the dancer r011 98 to the electric motor Mi which supplies the fabric at that require rate.

It will also be noted that the tentering frame or cloth stretching and guiding apparatus is lo-- printing zone so that it takes the fabric in its 76 shortened and laterally stretched condition and governs the tension of that fabric at the point of delivery to the printing roll. Hence, the width of the fabric is controlled so that it may be brought into substantial alignment with the printing roll, and at the same time the fabric is held under a required longitudinal tension. This insures that the fabric will be smooth both laterally and longitudinally and thus be in a proper condition for the printing step. This construction also insures that the edge of the fabric will be in alignment with a certain portion'of the printing roll, 50 that for some types of fabric it is possible to print to the extreme edge thereof; or if desired, a selvedge may be left unprinted but with the line of printing substantially straight and uniform. Various other advantages will be apparent in the above disclosure.

It will now be appreciated that numerous modificatiohs may be made in this construction and other apparatus employed therewith as desired by one skilled in the'art; hence the above disclosure is to be interpreted as illustrating the principles of this invention and a preferred embodiment thereof and not as limitations on the claims appended hereto.

I claim:

1. A textile printing apparatus comprising a printing machine having a power driven printing roll and a backing cylinder which draw the fabric forward at a given rate for the printing op eration, means providing a supply of fabric of non-controlled tension, a device for stretching the fabric to a uniform width, mechanism located between said device'and the printing zone for holding the fabric under a substantially uniform tension as it enters the printing zone, driving mechanism for feeding the fabric to the stretching device and means governed by movement of .the fabric which controls said driving mechanism and causes the fabric to be held under tension and to move at a controlled rate as it enters the stretching device.

2. A textile printing apparatus comprising a printing machine having a printing roll and driving means associated therewith for moving a strip of fabric into the printing zone, means providing a supply of fabric,'a device for stretching the fabric to a predetermined width and delivering it at a point close to the printing machine, driving mechanism for supplying the fabric to said stretching device at a controlled rate and under a given tension, mechanism controlled by the lateral wandering of the fabric while being stretched which guides it into substantially a predetermined path as it enters the printing machine, and means associated therewith which opposes the forward movement of the fabric caused by said driving means and holds it under a substantially uniform tension as it enters the printing zone.

3. A textile printing apparatus comprising a printing roll and driving means associated therewith for moving a strip of fabric into the printing zone, means for supplying fabric continuously for the printing operation, a tentering frame for stretching the fabric to a predetermined width and delivering it at a position close to the printing zone, means for moving the frame laterally and causing the fabric to travel substantially in a predetermined path, and means opposing the forward movement of the fabric caused bysaid driving means for holding the fabric delivered by the tentering frame under a substantially uniform but variable tension as it enters-the printing zone. I

4. A textile printing apparatus comprising a printing machine having driving means associated therewith for moving a strip of fabric into the printing zone, means providing a supply of fabric in a condition of uncontrolled tension, at tentering frame for stretching the fabric to a predetermined width and delivering it at a position close to the printing'zone, means controlled by the position of the traveling fabric for moving the frame laterally and causing the fabric to travel in substantially a predetermined path as it enters the printing zone, driving mechanism for feeding the fabric to the tcntering frame, mechanism controlled by the movement of the fabric which controls said driving mechanism and causes the fabric to be held under tension as it enters the tentering frame and automatically controlled mechanism which opposes the forward movemcnt of the fabric caused by said driving means and maintains the stretched and guided fabric under a predetermined and substantially uniform but variable longitudinal tension as it enters the printing zone. Y.

STEPHEN'B. STAFFORD.

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