US3438559A - Web tension means - Google Patents

Description

April 15, 1969 A. F. SHIELDS 3,438,559

WEB TENSION MEANS Sheet l of 2- Filed Jan. 11, 1967 INVENTOR. A! 55/?7 5 671051.06

April 15, 1969 A. F. SHIELDS 3,438,559

WEBTENSION MEANS Filed Jan. 11, 19s? Sheet 2 of z I NVENTOR. ALBERT f fry/105 United States Patent 3,438,559 WEB TENSION MEANS Albert F. Shields, 43 Exeter St., Forest Hills, N.Y. 11375 Filed Jan. 11, 1967, Ser. No. 608,656 Int. Cl. B65h 23/10 U.S. Cl. 226-195 3 Claims ABSTRACT OF THE DISCLOSURE Constant tension is applied to a web moving across a porous portion of a suction chamber support surface. Adjustable slideable cover-guide devices are mounted at opposite ends of the suction chamber to guide the web and cover those sections of the support surface porous portions outboard of the side edges of the web.

This invention relates to suction type tensioning means for moving web material and more particularly relates to suction means of this type having novel adjustable cover-guide devices which prevent unwanted loss of suction and reduce noise.

For many industrial processes, such as the production of corrugated board, it is necessary to move elongated web material at high speed from a supply means usually in the form of a large roll of the material in question mounted on a mill roll stand. In order to provide elfective control of the web entering the processing apparatus, it is necessary to provide a tensioning force.

The prior art has utilized magnetic brakes for obtaining such a tensioning force but this has proven to be unsatisfactory in many respects. In particular, the magnetic braking force is applied to the rotational sup port for the mill roll rather than directly to the web so that the braking force must be varied in accordance with roll diameter. When the mill roll is not perfectly round, the diameter sensing means is unable to transmit a signal with suificient rapidity to vary the magnetic braking force in a manner which will maintain constant web tension.

The prior art has attempted to overcome the difliculties noted above by utilizing a suction device for application of a tensioning force. However, prior art constructions of so-called suction brakes have been such that when narrow webs are handled, a good deal of the porous suction support surface is exposed causing a large loss of suction coupled with an increase in audible noise to an objectionable level.

The device of the instant invention overcomes the disadvantages of prior art suction web tensioning apparatus by including adjustable devices at each edge of the web. Each of these devices includes a guide portion and a flexible non-porous covering portion. In operation, the device is moved to a position wherein the guide portion lies adjacent to an edge of the Web to guide the latter over the tensioning apparatus while the flexible cover is positioned over the porous portion of the suction chamber lying outboard of the web edge. Thus, the porous portions of the support surface that are not covered by the web are covered by the flexible cover portions of the adjustable devices so that there is no unwanted loss of suction and operating noise is materially reduced.

Accordingly, a primary object of the instant invention is to provide a novel construction for a so-called suction brake which provides tension acting on a moving web.

Another object is to provide a suction brake of this type which will provide constant tension of the web regardless of the shape of the roll from which the web ice is being supplied. That is, whether the roll may be eggshaped, loosely wound, or be a butt, web tension will remain substantially constant thereby preventing fracturing of the web by eliminating inertial shock.

Still another object is to provide a tensioning means of this type which maintains relatively constant tension without the necessity of sensing supply roll diameter.

A further object is to provide a suction tensioning means which is adjustable to accommodate diflFerent web widths.

A still further object is to provide a web tensioning means of this type which reduces shock loads and fluttering of the Web.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE 1 is a perspective of a suction tensioning means constructed in accordance with the teachings of the instant invention.

FIGURE 2 is a plan view of one of the cover-guide devices of FIGURE 1.

FIGURE 3 is a side elevation of the cover-guide device of FIGURE. 2 looking in the direction of arrows 3-3.

FIGURE 4 is a cross section taken through line 44 of FIGURE 3 looking in the direction of arrows 44.

FIGURE 5 is an end view of the cover-guide device of FIGURE 2.

FIGURE 6 is a schematic showing two tensioning means units of the type shown in FIGURE 1 supporting webs of paper feeding into a single facet.

Now referring to the figures. Suction web tensioning unit 10 of FIGURE 1 appears twice in the schematic of FIGURE 6 which shows apparatus for producing single face corrugated board from webs of kraft paper 11, 12.

More particularly, web 11 is stored in roll 13 mounted to mill roll stand 14 and is drawn from roll 13 in the direction indicated by arrow A passing through tensioning means 10 at the left of FIGURE 6, through preconditioner 15 where moisture and heat are added thereto, and then passing into the corrugating rolls (not shown) of single facer 16. Web 11, after being corru gated by single facer 16, is combined with the liner provided by web 12. Web 12 is drawn in the direction indicated by arrow B from roll 17 mounted to mill roll stand 18. Web 12 after leaving roll L7, passes through suction tensioning means 10 at the right of FIGURE 6 and then through preheater 19 where web 12 is heated. From preheater 19 web 12 passes into single facer 16 where, in a manner well known to the art, web 12 is bonded to the tips of the corrugation-s formed in web 11 to produce single face board 99.

In order to achieve high quality production at fast speeds, it is necessary to apply a substantially constant force tensioning webs 11 and 12 prior to their entry into single facer 16. As will hereinafter be seen, the required constant tensioning forces are supplied by suction tensioning devices 10, 10 both depending from bridge structure 21 extending over single facer 16.

As best seen in FIGURE 1, suction tensioning device 10 includes elongated suction chamber 22 extending at right angles to the direction of paper travel and having a porous arcuate upper support surface 23 with nonporous sections 24 at each end thereof extending outboard of horizontally spaced vertical frame members 25, 26. Chamber 22 extends through apertures 25a, 26a, in members 25, 26, respectively, at the lower ends thereof and is fixedly secured to members 25, 26 by welds (not shown). Transverse frame member 27 has its opposite ends fixedly secured to members 25, 26, at the upper ends thereof, Centrifugal air pump 31 is driven by motor 32 mounted to stand 33 secured to one leg of channel 34 mounted above member 26 with the other leg of channel 34 fixedly secured to member 26. Flexible conduit 35 is connected at one end thereof to the intake of pump 31 while the other end is connected to the left end of chamber 22.

Damper assembly 36, mounted to the right end of chamber 22, is provided with handle 37 for manually adjusting the flow controlling vane (not shown) of damper 36. Screen 38 at the end of damper 36 prevents relatively large objects from being drawn through chamber 22 by pump 31. Meter 39 is connected to one end of tube 81 having its other end connected to chamber 27 at the lower center portion thereof. Meter 39 is mounted to the outboard surface of member 25 and provides an easily readable indication of the suction pressure within chamber 22 while damper 36 is being adjusted.

Identical cover-guide devices 40 are mounted at opposite ends of support surface 23, and are slidable along surface 23. Now referring more particularly to FIGURES 2 through for detailed illustrations of the construction of one of the cover-guide devices 40 consisting of longitudinally extending angles 41, 42, C- shaped handles 43, 44, clamps 45, 46 and flexible cover 47 constructed of a rubber-like plastic which may be fabric reinforced. The free ends of handle 43 are welded to one end of each of the brackets 41, 42, While the free ends of handle 44 are Welded to the other ends of brackets 41, 42. One of the long edges of cover 47 is interposed between clamp 45 and bracket 41, being held in place by a plurality of screws 45a passing through clearance apertures in clamp 45 and cover 47 into threaded apertures of bracket 41. In a similar manner, the other long edge of cover 47 is interposed between clamp 46 and bracket 42 being secured by a plurality of screws 46a passing through clearance apertures in clamp 46 and cover 47 being received by threaded apertures in bracket 42.

As best seen in FIGURE 5, brackets 41, 42 are so positioned that they cooperate with the protruding longitudinal edges 23a, 23b of support surface 23 to prevent cover-guide device 40 from being lifted off of chamber 22 or being dragged in the direction of sheet travel. Instead, movement of device 40 is confined along the axis of chamber 22 with cover 47 resting on surface 23.

In operation, it is intended that devices 40, 40 be moved to positions along surface 23 wherein handles 43, 43 lie adjacent to opposite edges of the moving web supported by surface 23. There is generally a small clearance gap 4 in. to /2 in.) set between each edge of the moving web and the guide portion of the adjacent handle 43 to permit limited weave of the web.

Adjustment of devices 40, 40 so that their covers 47, 47 close the porous portion of surface 23 outboard of the web edges reduces noise and maintain the suction force drawing the web against surface 23 with this force acting to tension the web as it is being drawn into the processing apparatus consisting of single facer 16.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Apparatus for tensioning web material moving parallel to its longitudinal axis along a predetermined path; said apparatus including a support surface extending across said path and having a porous section, a suction chamber partially defined by said support surface, suction pump means connected to said chamber, first and second devices disposed outside of said chamber at opposite sides of said path; means adjustably mounting said devices to said chamber for movement to positions Wherein each of said devices has a relatively non-porous flexible portion covering that portion of the porous section outboard of an edge of web material supported by said surface, each of said devices also including a guide portion positioned adjacent" to an edge of web material supported by said surface, means for guiding movement of said devices generally horizontally and at right angles to direction of movement of web material supported by said surface, an adjustable damper means, said chamber being elongated with said damper means connected to said chamber at one end thereof and said pump means connected to said chamber at the other end thereof.

2. Apparatus as set forth in claim 1 in which the support surface includes non-porous sections outboard of said porous section.

3. Apparatus as set forth in claim 1 in which each of said flexible portions is constructed of synthetic sheet material.

References Cited UNITED STATES PATENTS 1,949,237 2/1934 Bradner 226 X 3,259,288 7/1966 Wasserman 226-195 X 3,281,957 11/1966 Ranney 226l99 X M. HENSON WOOD, JR,, Primary Examiner. R. A. SCHACHER, Assistant Examiner.

' U.S. Cl. X.R. 226-499

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