SANDING OF ROLLERS

Abstract

A sand paper holder can be used to control sand paper that is being used to sand machinery at a distance from the equipment. The sand paper holder has a shield plate mounting a handle on one side and a clamping mechanism on the other side. The clamping mechanism securing holds ends of the sand paper. The shield plate provides a barrier between the hand of a technician holding the sand paper holder and the machinery. A method of sending using the sand paper holder is also described.

Description

FIELD

The present disclosure generally relates to devices uses to sand rollers of the type used in a manufacturing process.

BACKGROUND

The production of polymeric films, as well as the use of such films to produce articles of manufacture requires substantial automated handling. Much of the handling is accomplished by having the polymeric film pass over rollers. The rollers handle the film for proper positioning in manufacture. However, in addition to that the rollers can be used for affecting the material properties of the film, such as by stretching the film in a controlled manner. However, in the course of handling and acting upon the polymeric film the rollers themselves become fouled with material from the polymeric film. In the course of time, this fouling makes the roller inoperable for the purpose of handling and stretching the film or modifying its material properties. In practice, the rollers are restored by sanding to rollers to remove the material deposited on the rollers from the polymeric film.

Referring now to FIG. 1 of the drawings, a typical system of rollers used for handling or processing polymeric film is schematically illustrated. The roller system includes a support rack 20 (only partially illustrated). A surface roller 22 is mounted by other support structure adjacent to the support rack 20. A nip roller 24 is mounted adjacent to the support rack 20 in closely spaced position with the surface roller 22. An idler roller 26 is mounted forward (as oriented in FIG. 1) and slightly above the surface roller 22. First through fourth stretch rollers 28, 30, 32, 34 are mounted on the support rack 20 at generally vertically spaced positions from each other. The stretch rollers 28, 30, 32, 34 are progressively horizontally offset from each other from top to bottom toward the interior of the roller system. A pinch roller 36 is mounted forward of and close to the first stretch roller 28. The pinch roller 36 can be biased to yieldably press against the first stretch roller 28. A brake roller 38 is mounted forward of and slightly below the fourth stretch roller 34. The configuration illustrated in FIG. 1 is one of many possible combinations of rollers and roller positions that may be used.

In the configuration shown in FIG. 1, it is necessary to sand the surface roller 22, the stretch rollers 28-34 and the brake roller 38. The rollers requiring sanding will vary based on the material handled and the setup of the rollers. Conventionally, the way this is done is to provide an elongate piece of sand paper 42 that has a smooth side and a course (sanding) side. The smooth side has no grit and the sanding side has grit. In order to sand, for example, the third stretch roller 32, the piece of sand paper 42 is threaded lengthwise between the second stretch roller 30 and the third stretch roller, and then between the third stretch roller and the fourth stretch roller 32. This threading operation is done so that the smooth side of the sand paper 42 faces toward and engages the second stretch roller 30 and also the fourth stretch roller 34. The course side of the sand paper 42 engages only the third stretch roller 32. As a result of this threading operation, the two free longitudinal ends of the piece of sand paper 42 are located on the same side of the roller system.

The longitudinal ends of the sand paper 42 are held by one maintenance technician and another technician or machine operator causes the roller system to jog. Jogging the roller system causes all of the rollers to turn at a rate much slower than operating speed of the roller system, while the piece of sand paper 42 remains stationary. Engagement of the smooth surfaces of the sand paper 42 with the second stretch roller 30 and the fourth stretch roller 34 allows the second and fourth stretch rollers to slide without any significant abrasion of the surfaces of the second and fourth stretch rollers. However, the surface of the third stretch roller 32 is beneficially abraded as a result of the relative movement of the third stretch roller 32 with respect to the course side of the sand paper 42. The friction force between the sand paper 42 and the third stretch roller 32 tends to cause one of the longitudinal ends of the sand paper to be forcefully pulled toward the third stretch roller. The maintenance technician must take care to brace against this force in the sanding operation.

SUMMARY

In one aspect, a sand paper holder for holding ends of an elongate piece of sand paper generally comprises a shield plate having a first face and a second face on opposite sides of the shield plate. A clamping mechanism mounted on the first face of the shield plate is configured to receive opposite end margins of the elongate piece of sand paper and to clamp the end margins so as to secure the end margins in the clamping mechanism. A handle is mounted on the second face of the shield plate. The shield plate includes a transparent portion positioned so that when the sand paper holder is held by the handle on the second face of the shield plate a user may view the clamp mechanism and piece of sand paper held by the claim through the shield plate.

In another aspect of the present invention, a method of sanding rollers of a plastic film handing apparatus is disclosed. The film handling apparatus includes a surface roller, first and second stretch rollers and a brake roller, mounted for rotation about parallel axes. The method generally comprises passing a smooth surface of an elongate piece of sand paper around a segment of the surface roller, and passing a course, sanding surface of the piece of sand paper around a segment of the first stretch roller for use in sanding the first stretch roller. The smooth surface of the piece of sand paper is passed around a segment of the second stretch roller. Free end edge margins of the piece of sand paper are secured in a sand paper holder. The surface roller, first and second stretch roller and brake roller are caused to turn thereby sanding a surface of the first stretch roller.

Other objects and features of the present disclosure will be in part apparent and in part pointed out herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, perspective of a roller system illustrating a prior art sanding operation for one of the rollers;

FIG. 2 is a perspective of a sand paper holder from a bottom vantage;

FIG. 3 is a perspective of the sand paper holder from a top vantage;

FIG. 4 is a section taken in the plane including line 4-4 of FIG. 2;

FIG. 5 is a perspective of a first clamp jaw of the sand paper holder;

FIG. 6 is a perspective of a second clamp jaw of the sand paper holder;

FIG. 7 is a schematic, perspective of another roller system illustrating sanding a stretch roller using the sand paper holder;

FIG. 8 is a schematic, perspective similar to FIG. 7, but illustrating sanding a different stretch roller; and

FIG. 9 is a schematic, perspective similar to FIG. 7, but illustrating sanding a surface roller and nip roller using the paper holder.

Corresponding reference numbers indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION

Referring now to FIGS. 2-4 of the drawings a sand paper holder 50 for holding ends of an elongate piece of sand paper is shown to include a shield plate 52. The shield plate includes a first face 52A and a second face 52B on the opposite side of the shield plate from the first face. A clamping mechanism 54 is mounted on the first face 52A of the shield plate 52 by bolts 56 that extend through the shield plate and are threadably received in openings 58 of flanges 60 of a housing 61 of the clamping mechanism. The flanges 60 lie against the first face of the shield plate. The clamping mechanism 54 is configured to receive opposite longitudinal end margins of an elongate piece of sand paper, and clamp the end margins so as to secure the end margins in the clamping mechanism. A handle 62 is mounted on the second face 52B of the shield plate 52. Bolts 64 extend from the first face 52A of the shield plate 52, through the shield plate and into threaded openings of the handle 62 to securely fix the handle to the shield plate. The shield plate 52 is transparent in its entirety, although it is to be understood that only a portion of the shield plate need be transparent within the scope of the present invention. In still other embodiments within the scope of the present invention, the shield plate 52 can be opaque. The sand paper holder 50 can be held by the handle 62 at the same time that longitudinal end margins of the sand paper are held in the clamping mechanism 54 and received around rollers (e.g., one or more of the rollers 22-38 described in the Background). As will be described more fully hereinafter, the transparency of the shield plate 52 allows a maintenance technician (a “user”) to view the clamping mechanism, sand paper and roller(s) during a sanding operation.

The shield plate 52 has a perimeter 68 defined by the narrow minor surface of the shield plate that extend between and connect the first face 52A to the second face 52B. The perimeter 68 extends in a rectangle in the illustrated embodiment, although other shapes could be employed. The handle 62 is located entirely within the perimeter 68 of the shield plate 52. Stated another way, a projection of the minor surfaces forming the perimeter 68 in the direction of the second face encloses all of the handle 62. Thus, no portion of the hand of the maintenance technician holding the sand paper holder 50 by gripping the handle 62 is exposed. In some embodiments, the handle 62 is formed by grip enhancing material and/or grip enhancing features to permit the maintenance technician to maintain a tight grip on the handle.

The handle 62 has a width and a length that is greater than the width. Similarly, the housing 61 has a width and a length that is greater than the width. As mounted on the shield plate 52, the length of the handle 62 is transverse to the length of the clamping mechanism 54. As explained more fully below, the clamping mechanism 54 holds the sand paper so that the major surfaces of the sand paper lie in planes which are parallel to the length of the housing 61. Other arrangements of the handle 62 and clamping mechanism 54 are possible. The illustrated disposition of the handle 62 and clamping mechanism housing 61 are believed to provide good stability during sanding and also facilitate moving the sand paper laterally to progress sanding of an entire roller.

The housing 61 of the clamping mechanism 54 has an internal cavity that has an opening 72 that opens the cavity at an end of the housing remote from the first face of the shield plate 52. The opening 72 can receive the longitudinal end margins of the sand paper into the housing 61. The clamping mechanism 54 further includes a first clamp jaw 76 received in the cavity of the housing 61. The first clamp jaw 76 is movable with respect to the housing 61. A second clamp jaw 78 is also received in the cavity of the housing 61, but is fixed in position with respect to the housing 61, by bolts 79 connecting the second clamp jaw to the housing. The first clamp jaw 76 has a clamping face including a pair of narrow ribs 80 in the middle, and wider ribs 82 on its longitudinal edges (see, FIG. 5). The second clamp jaw 78 has a clamping face including central channels 84 and outer channels 86 (FIG. 6). The narrow ribs 80 of the first clamp jaw 76 are arranged with respect to the central channels 84 of the second clamp jaw 78 so that the narrow ribs are received in the central channels as the clamping faces of the first and second clamp jaws move together. Likewise, the wider ribs 82 of the first clamp jaw 76 are received in the outer channels 86 of the second clamp jaw 78 as the clamping faces of the first and second clamp jaws move together. When the longitudinal end margins of the sand paper are received between the first and second clamp jaws 76, 78, the narrow ribs 80, wider ribs 82, and central channels 84 and outer channels 86 deform the end margins back and forth between the clamping faces of the first and second clamp jaws to tightly grip the end margins and prevent them from being pulled out of the clamping mechanism 54.

The clamping mechanism 54 also has first and second guides or rods 90 received through opening in a side of the housing 61. The first and second guide rods 90 each include a smaller diameter, threaded end portion 90A that threads into the first clamp jaw 76. Each of the guide rods 90 has a larger diameter, smooth portion 90B that is in close, sliding engagement with the housing 61 (FIG. 4). The first clamp jaw 76 and first and second guide rods 90 move conjointly with each other in the housing. The engagement of the larger diameter portions 90B of the guide rods 90 with the housing 61 guides movement of the first clamp jaw 76. The number of guide rods may be fewer or more than two within the scope of the present invention. Springs 92 on each rod 90 are compressed between a head 90C of the rod and an annular surface of the housing 61. A clamp tightening bolt 94 is located generally between the guide rods 90 on the housing 61. The clamp tightening bolt 94 is threadably engaged with the side of the housing 61 and abuts the first clamp jaw 76. Rotating the clamp tightening bolt 94 in one direction moves the bolt into the housing 61, pressing against the first clamp jaw 76 and forcing the first clamp jaw to move toward the second clamp jaw 78 to clamp the longitudinal end margins of the sand paper in the clamping mechanism 54. This movement also results in greater compression of the springs 92. Rotation of the clamp tightening bolt 94 in an opposite direction removes the force of the bolt acting on the first clamp jaw 76. The springs 92 cause the first clamp jaw 76 to move away from the second clamp jaw 78 when the clamp tightening bolt 94 is backed off.

Having described the construction of the sand paper holder 50, some embodiments of its use will be described. To begin a sanding operation, doors which are part of a structure (not shown) separating the roller system are opened. Magnets or other suitable devices (not shown) are put in place at sensors (not shown) in order to permit the rollers to be operated with the doors open are installed. The stretch rollers 28-34 are moved to their opened positions. This is a conventional preparatory technique. Referring now to FIG. 7, a roller system similar, but not identical to the roller system shown in FIG. 1, is shown. Corresponding rollers are given the same reference numerals as in the FIG. 1 embodiment. The primary differences are that the pinch roller 36 is divided into three rollers that are independently mounted. It will be understood that the number of pinch rollers can be other than shown. Moreover, the pinch rollers 36 are located slightly above the first stretch roller 28. This roller system also has four stretch idle steel rollers 15 mounted for rotation on the support rack 20.

The nip roller 24 is moved into engagement with the surface roller. Placement of the sand paper 42 into the roller system for sanding the third stretch roller 32 occurs next. The elongate sand paper 42 is fed endwise over the top of the nip roller. The sand paper 42 is oriented so that the smooth surface of the sand paper engages the nip roller 24. The sand paper 42 is then fed around the third stretch roller 32 so that the sanding surface of the sand paper engages the surface of the third stretch roller. Next, the sand paper 42 is fed around the fourth stretch roller 34 so that the smooth surface of the sand paper engages the fourth stretch roller. The length of the sand paper 42 is selected to that the free longitudinal ends of the sand paper are located outside of the doors of the structure enclosing the roller system.

The free end margins of the sand paper are fed into the opening 72 of the housing 61 of the clamping mechanism 54 of the sand paper holder 50. The free end margins are placed between the first clamp jaw 76 and the second clamp jaw 78. While holding the sand paper holder 50 so that the longitudinal end margins of the sand paper 42 are positioned between the first and second clamp jaws 76, 78, the clamp tightening bolt 94 is turned clockwise. The clamp tightening bolt 94 moves further into the cavity of the housing 61, pressing against the first clamp jaw 76. In response, the first clamp jaw 76 moves toward the fixed second clamp jaw 78, guided in its movement by the guide rods 90. The first clamp jaw 76 engages the sand paper 42, and deforms it between the narrow and wider ribs 80, 82 of the first clamp jaw and the central and outer channels 84, 86 of the second clamp jaw 78. In this way, the end margins of the sand paper 42 are tightly and securely held by the clamping mechanism 54.

An operator then presses and holds a jog button or the roller system, causing the rollers of the roller system to rotate at a rate below normal operating speeds (e.g., about 200 ft/min, as compared with 1,000-3,000 ft/min in normal operation). The maintenance technician holds the sand paper holder 50 outside the doors of the structure enclosing the roller system. The surface roller 22 and nip roller 24 slide easily past the stationary sand paper 42 because of their engagement with the smooth surface of the sand paper. The same may be said for the fourth stretch roller 34. However, the sanding surface of the sand paper engages the third stretch roller 32, sanding that roller as it turns about its axis. The maintenance technician's hand is separated from the rollers by the shield plate 52. The transparency of the shield plate 52 allows the maintenance technician to see the rollers and sand paper 42 through the sand paper holder 50 for effectively controlling movement and positioning of the sand paper. Using the sand paper holder 50, the maintenance technician advances the sand paper 42 along the length of the third stretch roller 34 (to the left as shown in FIG. 7). To complete the sanding process, the maintenance technician then causes the sand paper 42 to move back to the right using the sand paper holder 50.

Sanding of the first stretch roller 28 and the second stretch roller 30 can be accomplished in similar manner. However, the threading of the sand paper 42 through the roller system is carried out so that the course surface of the sand paper engages the first stretch roller 28 or second stretch roller 30. Sanding of the fourth stretch roller 34 can be carried out in a simpler manner. As shown in FIG. 8, a shorter piece of sand paper 42 can be looped around the fourth stretch roller 34 and its ends clamped into the sand paper holder 50. It is not necessary to have a more complex threading of the sand paper 42 because the location of the fourth stretch roller 34 allows the sand paper to be looped directly around the fourth stretch roller without contacting any of the other rollers. The sanding operation is carried out in the same way as described above for the third stretch roller 32.

The surface roller 22 and nip roller 24 can be sanded together. As shown in FIG. 9, the sand paper 42 can be looped directly around the surface roller 22 and nip roller 24 so that the sanding surface of the sand paper engages both the surface roller and the nip roller. The longitudinal end margins of the sand paper 42 are secured in the sand paper holder 50, as described. The sanding operation can be carried out in the same way as described previously for the third stretch roller 32. The maintenance technician uses the sand paper holder 50 to guide the sand paper 42 so that it passes the pinch rollers 36 so that only the smooth surface of the sand paper can engage the pinch rollers.

When introducing elements of aspects of the invention or the embodiments thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

Not all of the depicted components illustrated or described may be required. In addition, some implementations and embodiments may include additional components. Variations in the arrangement and type of the components may be made without departing from the spirit or scope of the claims as set forth herein. Additional, different or fewer components may be provided and components may be combined. Alternatively, or in addition, a component may be implemented by several components.

The above description illustrates the aspects of the invention by way of example and not by way of limitation. This description enables one skilled in the art to make and use the aspects of the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the aspects of the invention, including what is presently believed to be the best mode of carrying out the aspects of the invention. Additionally, it is to be understood that the aspects of the invention are not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The aspects of the invention are capable of other embodiments and of being practiced or carried out in various ways. Also, it will be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

It will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

The Abstract and Summary are provided to help the reader quickly ascertain the nature of the technical disclosure. They are submitted with the understanding that they will not be used to interpret or limit the scope or meaning of the claims. The Summary is provided to introduce a selection of concepts in simplified form that are further described in the Detailed Description. The Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the claimed subject matter.

Claims

1. A sand paper holder for holding ends of an elongate piece of sand paper, the sand paper holder comprising: a shield plate having a first face and a second face on opposite sides of the shield plate;a clamping mechanism mounted on the first face of the shield plate and configured to receive opposite end margins of the elongate piece of sand paper and to clamp the end margins so as to secure the end margins in the clamping mechanism;a handle mounted on the second face of the shield plate;wherein the shield plate includes a transparent portion positioned so that when the sand paper holder is held by the handle on the second face of the shield plate a user may view the clamp mechanism and piece of sand paper held by the claim through the shield plate.

2. The sand paper holder as set forth in claim 1 wherein the shield plate is transparent in its entirety.

3. The sand paper holder as set forth in claim 1 wherein the shield plate has a perimeter and the handle is located entirely within the perimeter of the shield plate.

4. The sand paper holder as set forth in claim 1 wherein the handle has a width and a length that is greater than the width, and the clamping mechanism has a width and a length that is greater than the width, the handle and clamping mechanism being mounted on the shield plate so that the length of the handle is transverse to the length of the clamping mechanism.

5. The sand paper holder as set forth in claim 1 wherein the clamping mechanism comprises a housing having an opening and a clamp jaw received in the housing and movable with respect to the housing.

6. The sand paper holder as set forth in claim 5 wherein the clamp jaw constitutes a first clamp jaw, the clamping mechanism further comprising a second clamp jaw received in the housing.

7. The sand paper holder as set forth in claim 6 wherein the second clamp jaw is fixed with respect to the housing.

8. The sand paper holder as set forth in claim 6 wherein the clamping mechanism comprises a guide attached to the housing and operatively engaging the first clamp jaw to guide movement of the first clamp jaw.

9. The sand paper holder as set forth in claim 8 wherein the guide constitutes a first guide, the sand paper holder further comprising a second guide attached to the housing and operatively engaging the first clamp jaw to guide movement of the first clamp jaw.

10. The sand paper holder as set forth in claim 8 further comprising a spring having a first end engaging the guide and a second end engaging the first clamp jaw and biasing the first clamp jaw to an open position.

11. A method of sanding rollers of a plastic film handing apparatus including a surface roller, first and second stretch rollers and a brake roller, mounted for rotation about parallel axes, the method comprising the steps of: passing a smooth surface of an elongate piece of sand paper around a segment of the surface roller;passing a course, sanding surface of the piece of sand paper around a segment of the first stretch roller for use in sanding the first stretch roller;passing the smooth surface of the piece of sand paper around a segment of the second stretch roller;securing free end edge margins of the piece of sand paper in a sand paper holder;causing the surface roller, first and second stretch roller and brake roller to turn thereby sanding a surface of the first stretch roller.

12. The method of sanding rollers as set forth in claim 11 further comprising moving the piece of sand paper lengthwise of the surface roller, first and second stretch rollers and brake roller and then causing the surface roller, first and second stretch rollers and brake roller to turn thereby to sand a different longitudinal circumference area of the first stretch roller.