US3464612A

US3464612A - Strip feeding device

Info

Publication number: US3464612A
Application number: US666767A
Authority: US
Inventors: John F Dalton; Philip P Sharples
Original assignee: Mohawk Data Sciences Corp
Current assignee: Momentum Systems Corp; Mohawk Systems Corp
Priority date: 1967-09-11
Filing date: 1967-09-11
Publication date: 1969-09-02
Anticipated expiration: 1986-09-02

Description

Sept. 2, 1969 J. F. DALTON ET AL 3,464,612

STRIP FEEDING DEVICE Filed Sept. 11, 1967 3 Sheets-Sheet l INVENTOR. JOHN E DALTON Y PHILIP P. SHARPLES A TTORNE Y Sept. 2, 196% DALTON ET AL 3,464,612

STRIP FEEDING DEVICE Filed Sept. 11, 1967 5 Sheets-Sheet 2 Sept. 2, 1969 DALTON ET AL STRIP FEEDING DEVICE 3 Sheets-Sheet 5 Filed Sept. 11, 1967 United States Patent York Filed Sept. 11, 1967, Ser. No. 666,767 Int. Cl. B65h 17/22 US. Cl. 226-155 Claims ABSTRACT OF THE DISCLOSURE A continuously rotating drive capstan is mounted on the end of a pivotable bellcrank and is positioned be neath a strip to be fed along the surface of a bedplate. Upon energization of a solenoid actuator the bellcrank is pivoted to move the capstan through an opening in the bedplate to engage and feed the strip. A leaf spring positioned above the strip and spanning the opening in the bedplate biases the strip against the capstan for feeding and, when the capstan is lowered, biases the strip against the bedplate for braking. A friction material on the bedplate immediately beneath the leaf spring enhances the braking operation.

BACKGROUND OF THE INVENTION This invention relates to strip feeding and, more particularly, to apparatus for feeding a strip in incremental steps such as may be done in the process of printing on the strip.

It is common practice to feed a strip or other type of continuous web by pressing the strip between a pair of rollers, one a powered drive roller and the other an idling backup roller. One roller, usually the idler, is mounted for selective movement toward and away from the strip so that feeding can be selectively interrupted. In this type of feed mechanism additional means are required to positively brake the strip against the effects of the drive roller during periods of non-feeding. Besides the obvious disadvantage of mutliplicity of elements, i.e., the brake and idler are separate mechanisms often requiring some kind of synchronized control, the use of an idler roller increases the dynamic mass of the system and thus increases the time required to accelerate the strip to the desired velocity. This is a decided drawback in systems calling for high speed incremental feeding.

OBJ'ECTS AND SUMMARY OF THE INVENTION It is therefore an important object of the invention to provide an improved high speed incremental strip feedin device having reduced dynamic mass.

Another object is to provide an improved strip feeding device which reduces the amount of hardware required by combining the functions of both the idler roller and the brake into a single non-rotating member.

In accordance with the principles of the invention, braking of the strip is performed by a brake spring which presses the strip against a bedplate. To effect feeding, a drive member engages the strip and lifts it and the brake spring away from the bedplate whereby the braking action is interrupted and the brake spring serves as a pressure member to hold the strip against the drive member during feeding. As an additional feature to enhance braking efliciency, a friction material, such as rubber, may be secured to the bedplate at the point against which the brake spring presses the strip. This enables the use of a low-friction surface on the brake whereby less friction drag is applied to the strip during feeding.

These and other objects, features and advantages will Patented Sept. 2, 1969 be made apparent by the following detailed description of -a preferred embodiment of the invention, the description being accompanied by drawings as follows:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation view, partially cut away, showing a preferred embodiment of the strip feeding device of the invention.

FIG. 2 is a left side elevation view of the device of FIG. 1.

FIG. 3 is a top plan view of the device of FIG. 1, the brake spring being omitted for clarity.

DETAILED DESCRIPTION Referring to FIGS. 1, 2 and 3, a strip 10 is fed to the left (as viewed in FIG. 1) along the surface of bedplate 12 by a drive capstan comprising a pair of rotating

drive rollers

46 and 47.

Rollers

46 and 47 engage the underside of strip 10 through a pair of

openings

14 and 15 in the bedplate. A leaf spring 16 having a widthsubstantially equal to that of strip 10 is suspended form a crossbrace 18 and forces the strip against the

rollers

46 and 47 for feeding and in the non-feeding state of the device forces the strip against the surface of bedplate 12 to accomplish braking.

The

rollers

46 and 47 are mounted on a common shaft 44 which is journalled for counterclockwise rotation (as viewed in FIG. 1) in the upper end of a bellcrank 20*. A pulley 42 is connected to shaft 44 and is driven in continuous rotation by a motor 36 (FIG. 3). The motor turns a shaft 22 which is journalled in a bearing 24 supported in a frame member 26. A pulley 34 is connected to shaft 22 and transmits the rotation thereof to pulley 42 by means of a belt 38.

Bellcrank 20 is mounted to pivot about the axis of shaft 22 by means of a tubular support member 28 (FIG. 3) fixed to frame 26 concentric with and surrounding, but not touching, shaft 22. The bellcrank is restrained against lateral movement by an end flange 32 on tube 28 and a shim 30.

As shown in FIG. 1, an electromagnet including a core 60 and coil 62 is positioned to attract a ferromagnetic insert 66 fixed to the lower end of the bellcrank 20. When coil 62 is energized, the crank 20' is pivoted clockwise against the bias of tension spring 68, which is fixed to frame member 69, and is drawn away from stop 70. To maximize the speed of this transition the crank 20 may be constructed of a lightweight material such as aluminum or magnesium and is provided with lightening holes such as 21 to further decrease the weight of the system. A pulse generator 64 is employed to supply a train of current pulses to effect high speed incrementing of the strip in the manner described below.

In operation, an elbow 17 in brake spring 16 forces strip 10 against the portion of the surface of bedplate 12 which lies between the openings .14 and 15. This maintains the strip in a stationary position. The rotating

drive rollers

46 and 47 do not engage the strip since the coil 62 is unenergized and spring 68 'biases bellcrank 20 against stop 70 whereby the rollers are held away from the strip.

When coil 62 is energized, the bellcrank pivots clockwise (as viewed in FIG. 1) until the insert 66 is arrested by the pole faces of core 60.

Rollers

46 and 47 are thus moved upwardly into contact with the underside of strip 10 and force it up and away from the surface of the bedplate. The brake spring 16 of course also rises and its biasing force acts to keep the strip engaged With the rollers. This causes the strip to be fed to the left along the path defined by guide pins 13.

Removal of the current from coil 62 causes spring 68 to pivot the bellcrank 20 counterclockwise back to its home position established by stop 70. This lowers

rollers

46 and 47 below the surface of bedplate 12 whereby the brake 16 forces the strip against the surface of the bedplate to instantly arrest its movement and hold it in the stopped position.

To enhance this braking and holding action, a layer of friction material 50 (FIG. 3), such as rubber, may be applied to the surface of the bedplate in the area between

openings

14 and 15. During feeding,

rollers

46 and 47 lift the strip enough to cause it to pass over this area. This then enables the use of a low-friction coating such as Teflon to be employed on the underside of elbow 17 of spring 16 to reduce the drag of friction to a minimum during feeding.

To assist strip loading and manual control of the feeding operation an arm 41 is provided on crank 26 and protrudes beyond the side cover of the device. This facilitates manual raising and lowering of the

rollers

46 and 47. An extension 19 is provided on spring 16 for the same purpose.

The pulse generator 64, in supplying a train of current pulses to coil 62, effects incremental feeding of the strip 10. This mode of operation can be very rapid due to the low dynamic mass and friction of the system. Also, the positive and rapid braking action achieved by spring 16 enables highly accurate and reliable control of the strip. Additionally, it is apparent that the whole device is very inexpensive and, having few operating parts, allows for extended maintenance-free operation.

It will be apparent that various changes and modifications may be made in the above-described embodiment without departing from the true spirit and scope of the invention.

We claim:

1. A web feeding device comprising, in combination:

a bedplate adapted to support a web for feeding, said plate having an opening beneath the feed path of said web;

a resilient braking member spanning said opening for pressing said web against said plate in an area adjacent said opening; and

drive means positioned beneath said plate and constructed and arranged to be selectively movable through said opening to frictionally engage said web at a point directly opposite said braking member, said drive means lifting said web and said braking member away from said plate to effect feeding of said web.

2. The device set forth in claim 1, wherein said drive means comprises:

a capstan rotatable in a plane perpendicular to said feed path; and

control means for rotating said capstan and for selectively moving said capstan through said opening to engage said web for feeding.

3. The device set forth in claim 1, wherein said braking member comprises:

a leaf spring substantially as wide as said web and being mounted so as to engage said web across its full width.

4. The device set forth in claim 1, further comprising:

a coating of friction material fixed to said bedplate in an area directly beneath the area of said web which is engaged by said braking member.

5. The device set forth in claim 2 wherein said control means comprises:

a rotating drive shaft;

a bellcrank pivotable about said shaft;

means for journalling said capstan at one end of said bellcrank;

means transmitting the rotation of said shaft to said capstan; and

magnetic means acting on the other end of said bellcrank to pivot said bellcrank in a first direction, moving said capstan through said opening.

6. The device set forth in claim 5, further comprising: a spring acting on said other end of said bellcrank to bias it in a direction opposite said first direction.

7. The device set forth in claim 5 wherein said capstan comprises:

a pair of friction rollers mounted in spaced-apart relation on the same shaft, said bedplate having a separate opening beneath said web path for each roller.

8. The device set forth in claim 7, further comprising:

a coating of friction material fixed to said bedplate in an area between said two openings directly beneath the area of said web which is engaged by said braking member.

9. A web feeding device, comprising, in combination:

a stop surface;

a movable braking member for pressing said web against said stop surface, said member engaging said web along a line at least partially included in a plane which is substantially perpendicular to the direction of travel of said web;

drive means selectively operable to engage said web along a line also at least partially included in said plane and to move said web and said braking member away from said stop surface; and

means for imparting driving motion to said drive means to feed said web.

10. The device set forth in claim 9 wherein said drive means comprises:

a capstan selectively movable toward and away from said web to effect said engaging operation and rotatable to effect said feeding operation.

References Cited UNITED STATES PATENTS 9/1958 Woodcock 226l X 8/1959 Funnell 226- X