US1640532A - Web-feeding mechanism - Google Patents

Description

. 1,640,532 30, 1927- .1. s. COLDWELL WEB FEEDING MECHANISM Filed Nov. 2 1924 A TTORNE V Patented Aug. 30, 1927.

UNITED STATES 1,640,532 PATENT OFFICE.

1 JOHN S. COLDWELL, F MILWAUKEE, WISCONSIN, ASSIGNOR TO CUTLER-HAM- MER MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN. T

WEB-FEEDING MECHANISM.

Application filed November 26, 1924. Serial No. 752,318.

This invention relates to web feeding mechanism for printing presses and the like.

My copending application, Serial No. 683,306, filed December 29, 1923, discloses a web feeding mechanism wherein-the weight of the web roll and the supporting mechanism therefor serves to control braking means for regulating the tension on the proceeding web. While the braking means disclosed in this 1 application functions v'ery satisfactorily in so far as the same automatically maintains the tension on the proceeding web between predetermined limits without sudden variations therein the same does not. prevent over-running of the Web roll upon quick stopping of the press.

The present invention has among its objects to provide a web feeding mechanism of the character disclosed in the aforementioned application having emergency braking means associated therewith for preventing over-runing of the web roll upon quick stopping of the press.

Another object is to provide a web feeding mechanism of the aforesaid character wherein the emergency braking means is adapted to impose a predetermined dragging effect on the roll which is proportional to the weight thereof.

Another object is to magnetic operation of ing means.

Various other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates an embodiment ofthe invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the spirit and scope of the appended claims.

In the drawing, 4 Figure 1 is a simplified end view of. a web feeding mechanism embodying the invention Fig. 2 is a simplified side elevational view of the web feeding mechanism shown in igs. 3 and 4 are detail views partly in section of certain of the parks shown in Fig. 1, and,

provide for electrothe emergency brakmethod of controlling the emergencybraking means.

Referring to Figs. 1 and 2, the web feeding mechanism shown therein includes a pair Fig. 5 is a schematic view illustrating one of spindles 6 and 7 for supporting a web roll 8. Web roll 8 is provided with a .hollow core member, (not shown in the drawing),

and spindles 6 and 7 are adapted to be inserted into opposite ends of said core member tosupport the Web roll and to rotate therewith. Spindles 6 and 7 are rotatably mounted within suitable bearings carried by arms 9 and 10, respectively, and said arms are fixed to each other through the medium of, an intermediate connecting member 11,

and are rotatably mounted upon a support- 1 mg shaft 12. Each -of the spindles 6 and 7 has a brake drum 13 fixed thereto, and each of said brake drums is provided with a copending application.

For a purpose hereinafter set forth, the brake shoes 14 have electromagnetic means associated therewith for rocking the same on pivot pins 16, such means including electro-. magnetic windings 21 carried by the arms 15, and armature members 22 rotatably mounted on said pins. VVindings 21 are of annular form and, as shown in Fig. 3, each of the same is mounted within a recess 23 in its respective supporting arm 15, and is provided with a center core member 24. Each of the armature members 22 is provided with a pair of stops 27 arranged on opposite sides of its associated pivot pin 16, and said stops are adjustable to vary the angular position of each of said members relative to its associ ated brake shoe 14, for variation of the air gaps between said armature members and the pole faces of their. operating windings 21.

The function and operation of the aforedescribed web feeding mechanism will now be more fully described. Upon rotation of shaft 12, arms 15 act through the medium of brake shoes 14 and drums 13 to vary the angular position of the web roll with respect to the axis of said shaft, and when the web roll is held' in a given angular position the weight thereof is resolved into component forces, one of which tends to hold the drums 13 in engagement with their respective shoes 14. Assuming that the web roll is held in the angular position shown in Fig. 3; and that windings 21 are deenergized; the surface of the brake shoes 14 are concentric to the friction surfaces of the brake drums 13 and a component force then acts in the direction of line AB to hold said brake drums in engagement with their respective shoes. As set forth in my afore mentioned copending application, the component force acting in the direction of line A-B serves to maintain a substantially uniform' tension on the proceeding web, the value of such tension corresponding to the angular position of the web roll with respect to the axis of shaft 12.

To prevent over-running of the web roll upon quick stopping of the press windings 21 are energized to attract armature members 22. Upon attraction of armature members 22, the brake shoes are moved from the position shown in Fig. 3 to the position shown in Fig. 4, wherein only the lower end portions thereof are in engagement with the brakedrums. With brake shoes 14 in this position, the weight of the web roll is resolved into component forces, one of which acts substantially along the line CD to hold the brake drums 13 in engagement with said shoes. It is apparent that the force acting 'along the line C-D in Fig. 4 is considerably greater than the force I acting along the line AB in Fig. 3 whereby an augumented braking effect on the web roll is obtained. Furthermore, it is apparent that this augmented braking effect will vary in accordance with the weight of the web roll. Thus, for a given press speed the web roll will always be brought to rest in a given period of time regardless of the size thereof. The ratio of the augmented braking effectmelative to the normal braking effect can be varied by varying the position of the lower edge of the brake shoes with respect to a vertical plane passing through the axis ofthe web roll.

The above described web feeding mechanism is particularly adapted for use in connection with high speed printing presses. High speed printing presses are commonly stopped in emergencies by establishing a dynamic braking circuit for the driving motor and by utilizing the dynamic braking current of the motor to operate a plurality of electro-mechanical brakes adapted to act on certain of the press rolls. Such braking'means acts with a varying efi'ect approximately proportional to the kinetic energy of the press and serves to always bring the press to rest in a given period for a given press speed. The emergency braking means associated with the above described web feeding mechanism is thus particularly adapted for use in connection with such presses since the same can be readily designed to stop the web roll in a period corresponding to any given emergency stop speed of the press upon initiation of the braking action varies considerablv.

Referring to Fig. 5, the same diagrammatically illustrates a press of the character above described, one of the electro-mechanical brakes of the emergency stopping means being shown at 28 and the dynamicbraking circuit of the driving motor being indicated by lines L and L The windings 21 of the emergency stopping means associated with the web feeding mechanism are also shown in this figure, the same being connected in parallel across the dynamic braking circuit L L It is thus apparent that upon emergency stopping of the press, the emergency braking means associated with the web feeding mechanism is energized to provide for simultaneous stopping of the web roll. Also, it will be apparent that by so energizing the emergency brake magnets they will be deenergized automatically when the press comes to rest, thus restorin normal braking for tensioning of the we 7.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with a press supplied from a web roll, said press having means associated therewith for effecting emergencystopping thereof in a. given period for a given press speed, of means for stopping said web roll in a corresponding period, said means including a brake drum fixed to said roll and a cooperating brake shoe, said drum being held in engagement with said shoe under the action of substantially the entire weight of said web roll.

2. The combination with a motor driven presssupplied with material from a web roll, said press having emergency braking means rendered effective by current generated by its driving motor, of means for stopping said web roll upon emergency stopping of said press, said means including a drum fixed to said web roll and an associated brake shoe normally in a given position to effect a given braking effect on said web roll and movable to another position to effect an augmented dragging effect on said web roll and electro-magnetic means included in the dynamic braking circuit of the driving motor of said press for moving said shoe to its last mentioned position.

3. The combination with a press supplied with material froma web roll, said press having electro-mechanical braking means associated therewith for effecting emergency stopping thereof, of braking means associated with said web roll, said means being normally in a position to impose a given dragging efiect on said web roll and being movable to another position to impose a predetermined augmented dragging eifect on said roll for quick stopping thereof upon quick stopping of said press, and electroresponsive means to be energized simultaneously with the electro-mechanical braking means of said press, for moving the braking means associated with said web roll to its last mentioned position.

4. In a web feeding, mechanism for material drawn from a roll into a receiving machine, in combination, a brake drum fixed to said roll to rotate therewith, a brake shoe for engaging said drum, said drum being held in engagement with said shoe under the action of the weight of said web roll and said shoe being adapted in a position normal to said drum to impose a given braking effect on said web roll to tension the material drawn therefrom, and being movable to a position wherein the friction surface thereof is eccentric to the friction surface of said drum to provide an augmented fibraking effect on said web roll to prevent over-running thereof upon quick stopping of said receiving machine. k

5. In a web feeding mechanism for material drawn from a roll into a receiving machine, in combination, a brake drum fixed to said roll to rotate therewith, a cooperating brake shoe, said drum being held in engagement with said shoe under the action of the weight of said roll, and means for varying the angle of contact with respect to the aiiis of said web roll to provide braking effects of different values, one for tensioning the material drawn from-said web roll and the other for effecting quick stopping of said web roll upon quick stopping of said receiving machine.-

.6. In a web feeding mechanism for mate rial drawn from a web roll into a receiving machine, in combination, a brake drum fixed to said roll, a. brake-shoe for engaging said drum, said drum being held in engagement with said shoe under the action of the weight of said web roll and said shoe being adapted in a position normal to said drum to impose a given dragging effect on said web roll for tensioning of the material drawn therefrom, and being movable to a position wherein the friction surface thereof is eccentric to the friction surface of said drum to provide an augmented dragging effect on said web roll for quick stopping thereof upon quick stopping of said receiving machine, and electromagnetic means associated with said brake shoe for moving the same from its normal position to its last mentioned position.

In witness whereof, I have hereunto subscribed my name,

JOHN S. COLDWELL.

Images