US3831828A

US3831828A - Arrangement for aligning fabric material during rolling-up and unrolling operations

Info

Publication number: US3831828A
Application number: US00332303A
Authority: US
Inventors: R Royon; G Thillardon
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-02-22
Filing date: 1973-02-14
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: BE795702A; FR2173492A5; DE2300727A1; JPS48103890A; DE2300727B2; DE2300727C3; GB1424476A; IT977844B

Abstract

An arrangement for aligning sheet fabric material while being rolled up or unrolled for processing, in which the fabric is passed over an aligning roll member. One end of this roll member is pivoted, whereas the other end is displaced by a screw mechanism. The angular disposition of the roll member orients the material in predetermined direction. In conjunction with the angular variation of the roll member, the peripheral diameter of the roll member may be varied by rotating a shaft passing through the center of the roll member. A pair of oppositely-threaded portions on this shaft, mesh with female-threaded members carrying elongated elements which vary the peripheral diameter of the roll member as a function of the displacement of the femalethreaded members along the axis of the shaft.

Description

United States Patent [191 Royon et a1.

[ 11 Aug. 27, 1974 ARRANGEMENT FOR ALIGNING FABRIC MATERIAL DURING ROLLING-UP AND UNROLLING OPERATIONS [76] Inventors: Rene Royon, 15 rue de la Charriere,

4227 Saint Priest en Jarez; Georges Thillardon, 29 rue des Villas,

Residence Les Edelweiss 42100 Saint Etiene, both of Loire, France [22] Filed: Feb. 14, 1973 [21] Appl. No.: 332,303

[30] Foreign Application Priority Data Frisbie et a1. 226/21 2,782,030 2/1957 Webster et al 226/21 3,107,036 10/1963 Richards et 81]. 226/16 UX 3,108,727 10/1963 Farber 226/21 X Primary ExaminerM. Henson Wood, Jr. Assistant ExaminerGene A. Church Attorney, Agent, or FirmEric H. Waters ABSTRACT An arrangement for aligning sheet fabric material while being rolled up or unrolle-d for processing, in which the fabric is passed over an aligning roll member. One end of this roll member is pivoted, whereas the other end is displaced by a screw mechanism. The angular disposition of the roll member orients the material in predetermined direction. In conjunction with the angular variation of the roll member, the peripheral diameter of the roll member may be varied by rotating a shaft passing through the center of the roll 11"1P9E- .nairs Q212 xrthisas sqssr on this shaft, mesh with female-threaded members carryi ng elongated elements which vary the peripheral diameter of the roll member as a function of the displacement of the female-threaded members along the axis of the shaft.

20 Claims, 14 Drawing Figures 23 t t t t/ L PATENIED mczmu snmun PAIENIED mszmn SHEEI 2 0F 4 ll Ill] ll ll I I I I I I ARRANGEMENT FOR ALIGNING FABRIC MATERIAL DURING ROLLING-UP AND UNROLLING OPERATIONS BACKGROUND OF THE INVENTION Sheet material, particularly fabric material, is rolled up by machines in the art, for various purposes such as reconditioning, inspection, lapping, for example. The rolling up process for such operations is generally accomplished by mechanisms involving auxiliary feed rolls, motors and transmission, as well as tension arrangements.

In the processing of textiles, fabric is also unrolled, particularly when it is desired to unroll a bolt of cloth for the purpose of cutting strips of fabrics and stacking the cut strips onto a cutting table. In such arrangements, a stacking or padding carrier is used to travel along the length of the table while the cloth is unrolled.

The preceding conventional arrangements used in the art are adequate when detailing with substantially plain cloths or fabric material. However, when checkpatterns are used, problems arise involving cutting of the material so that the cut edges are parallel to the check-pattern lines. This precaution in cutting the fabric is essential in fabrics having check-patterns, so that the check-patterns are continuous on fabricated pieces sewn together, for example.

Aside from the pattern considerations, it is essential to provide for aligned travel of the cloth in a straightline manner when either rolling up the cloth or unrolling it. The conventional arrangements known in the art do not provide for such constantly aligned results, in view of the wrinkling of the cloth while being processed for further fabrication. For stacking cut sheets of fabric, the conventional arrangements provide substantially inadequate means in the form of two operators who locate the sections of the cloth on spike elements projecting through the cutting table. The operators stack these out sheets in accordance with a predetermined line on the fabric. Such stacking procedures as used in the prior art, heretofore, are laborious, and result in no more than substantially 60 to 80 pads or stacks per day. At the same time, such stacking procedures in the conventional art do not allow for proper matching of the lines of the cloth, and they often produce tears in the fabric.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an arrangement for aligning sheet material, particularly fabrics, while being rolled up or while being unrolled for cutting into predetermined lengths.

Another object of the present invention is to provide an arrangement for handling strip material in an aligned manner in textile processing operations.

A further object of the present invention is to provide a fabric aligning arrangement through which predetermined lengths of the fabric may be stacked at the rate of substantially 350 pads per day.

A still further object of the present invention is to provide an arrangement for rolling up sheet material and unrolling it in an aligned manner so that checkpatterns on the material may be precisely aligned when sewing or fitting together cut lengths of the material.

The objects of the present invention are achieved by providing a roll member over which the sheet material or fabric passes while being rolled up or unrolled. The roll member may be angularly oriented for aligning the sheet material in predetermined manner. Such angular orientation of the roll member serves to take up undesired slack in the sheet material which may result in wrinkling of the material. An optical arrangement may be used for the purpose of obtaining precise angular displacement of the roll member.

The arrangement, in accordance with the present invention, provides for means which executes forward and return strokes along an inspection or cutting table on which predetermined lengths cut from the rolled cloth, are stacked on the table. The stacked lengths of cloth may have patterns which are precisely aligned in the stacks. The stack lengths, may be used for further processing or cutting into articles of clothing. To achieve precise matching of lines or patterns on cut lengths of the fabric material when sewn or fitted together, starting or reference lines are marked on the sheet material for guidance purposes.

The novel features which are considered characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a functional diagram showing the unrolling of cloth to form stacks of cut lengths of check-patterns, using an optical arrangement for controlling the aligning of the check-patterns in accordance with the present invention;

FIG. 2 is a side view of the stacking carrier and cutting table, shown in FIG. 1, together with the driving and adjustment elements for accomplishing the alignment function;

FIG. 3 is a functional diagram of another embodiment of FIG. 1;

FIG. 4 is a partial functional diagram showing wrinkling of the cloth while being rolled up;

FIG. 5 is a partial sectional view of a stop mechanism for cuting predetermined lengths of the cloth in the arrangement of FIG. 1;

FIG. 6 is a side view in diagrammatic form, and shows the optical arrangement used for alignment purposes;

FIG. 7 is a sectional end view and shows the mounting of one end of a roll member used to align the cloth during processing;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 7;

FIG. 9 is a perspective view and shows the screw mechanism used to obtain a predetermined angular disposition of the roll member for obtaining alignment of the sheet material during processing;

FIG. 10 is a sectional diagrammatic view and shows the arrangement for varying the peripheral diameter of the roll member used for aligning; the sheet material during processing;

FIG. 11 is a sectional diagrammatic view of another embodiment of the arrangement of FIG. 10; and

FIGS. 12, 13 and 14 are side views of various possible embodiments of the roll feed member used to align the sheet material while being processed, in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing and in particular to FIGS. 1 and 2, an inspection or cutting table 1 is supported on a suitable stand and is provided with a padding or cushioning carrier 2. This carrier runs on the top of the table 1 by means of rollers or wheels 3. The carrier is steered or guided in its base 2a, by further or auxiliary wheels or rollers 4 and 5. These rollers 4 and 5 contact portions of the stand which supports a table.

The base member 2a holds in place an operators platform 6 which guides the motion of the carrier only when the latter is present on top.

Transfer elements or members 2b 20 support cradles 7 taking into account the center R1 of the bolt of cloth having a radius R. A roller 8 is mounted at the end of one of the cradle arms. In a similar manner, a further intermediate roller 9 is mounted on the transfers or cross member 20. The intermediate rollers 8 and 9 cause the cloth to follow a path in which the cloth is under tension and a steady regular supply of the cloth is obtained.

After passing over the intermediate roller 9, the cloth winds onto an auxiliary cross or transfer member 10 having a coating which prevents slippage of the cloth. The member 10 forms one of the components of the arrangement, in accordance with the present invention, from the viewpoint that this member is adjustable either angularly or diametrically, in a manner to be described. This member 10 can be also composed of several portions each equipped with a differential or other mechanism which permits variable speeds and strains for each of them, whereby the motion of a given portion may be modified for winding the cloth thereon.

The cloth next drops vertically between a transverse support bar 2d on the carrier and a cutting blade 11 mounted within an adjustable housing 12 and driven by a motor 13 or other suitable driving means.

After the cloth has been cut by the blade 11, the cut cloth is laid on the inspection table in proportion to the travel or stroke of the carrier. In this manner, several lengths of cloth are laid along the length of the table on the forward pass or motion. After return of the carrier in an idling manner, a new set of lengths is laid on top of the first ones, and this procedure is repeated until pads or stacks of lengths are built up preparatory to being cut into pieces of clothing.

The controls for controlling the motion of the carrier, for adjusting and driving the member 10, and for actuating the cutting blade, are all grouped together on a console 14, so that they are readily accessible to an operator standing on the platform 6.

A switch or push button 15 is, for example, provided to transmit the orders of the attendant or operator for tilting the auxiliary member 10 or feed roll so that the latter may tilt angularly during rotation or when stopping for the purpose of correcting any wrinkling of the cloth while being fed. FIG. 6 illustrates, for example, the member 10 tilting in the downward direction so that the fed or supplied cloth may have its wrinkles straightened in this manner. FIG. 4 illustrates another example related to take-up of the cloth, in which case the member 10 tilts upward.

The tilting adjustments for removing wrinkles in the cloth are performed as a result of the operators visual observation of the cloth being fed. In view of the exercise of such visual control, substantial accuracy cannot be obtained even when the operator has an experienced eye. An accurate and fast inspection device is also provided in the arrangement of a light 16 or a fluorescent tube which is held horizontally and is adjustable by a sloping or inclined arm 17. The fluorescent is preferably iodine. The sloping or inclined arm 17 is, for example, made integral with the support rail 2d, and is mounted within a casing 18 which allows a ray of light to pass through a fixed or rotatable aperture which may be adjusted. The light passing through the aperture is projected onto a rod, wire or tube 19 carried by the arm 17 or rail 2d. The element 19 is located in close proximity to the vertically descending cloth. The shadow of the element 19 appears on the cloth, and thereby an extremely well defined visible stripe or straight line is obtained which is perpendicular to the direction of motion of the cloth.

The lamp or light 16 can be mounted either in front of the cloth (FIG. 3) or behind the cloth (FIG. 1). From the viewpoint of the viewer, it is preferably that the light shine through, corresponding to a rear mounted lamp.

For the purpose of checking the squareness and straightness of the cloth in the form of the cut-out pieces of cloth laid on the table, a similar projectedshadow system is provided. For this purpose, several arrangements can be used in the form of gantry mounting, tunnel, etc. The embodiments of FIGS. 1 and 6 show a sectional framework 20 corresponding to the size of the table, and having iodine lamps 21 hanging on adjustable supports 22 within casings 23, at various points along the length of the table. The lamps and casings allow the emission of concentrated light toward the tubes or rails 24 carried by the framework 20, so that a straight shadow is projected squarely to the travel or motion of the carrier over the table, and onto the lengths of cloth.

It is to be noted that a shadow is essential for every starting line of the cloth (a distinctive line superimposed on the starting line of the master stencil). For this purpose, a rotatable and adjustable casing 23 may be provided as shown in FIG. 1, so that the light transmitted obliquely across other tubes 24 may cast a shadow accurately in accordance with the position of the second, third, etc., starting line of the master pattern, when required.

As already mentioned, the auxiliary feed roll can be designed or fabricated in several different ways and in one or more parts, by the use of differential or other mechanisms, and may be made angularly adjustable and diametrically adjustable, for example. FIGS. 7 to 10 show particular embodiments of the feed roll 10 when in the form of a single part and rotatably adjustable.

The feed roll 10 may be driven by any suitable means, and is connected through its central member 10a, to a block 25 which is integral with an upright member 2e of the carrier. The joint or connection consists of a sleeve 26 having an aperture 26a through which the central shaft portion or member 10a passes freely. A pivot stud or member 27 held within the block 25 (FIGS. 7 and 8) passes, furthermore, through the central shaft portion 10a. The other end of the central portion 10a is slidably mounted within a bearing 28 which is attached to a nut 30 by means of the horizontal fastening element 29. The nut 30 operates in conjunction with a threaded member or worm 31. The threaded rod is driven either manually or by a motor 32 (FIGS. 2 and 9) which is attached to a bearing block 33 integral with a column member 2f of the carrier. The bearing block 33 has arms between which the threaded rod is mounted.

When arranged in accordance with the design described above, the roll 10 can be moved or tilted angularly as illustrated in FIGS. 2 and 4, for the purpose of removing wrinkles from the cloth.

The bearing block 33 may also be supported in an adjustable arrangement of other design which will allow for adjustments of the roll 10 for vertical settings, particularly for alignment in the vertial direction of the warp lines, for example, in the fabric. Furthermore, markers or other similar indicating means may be arranged on the bearing 28 or nut 30, as well as on the bearing block 33 for the purpose of orienting the roll 10 readily into the horizontal position (FIG. 2). At the same time, switching contacts 40 located at the extreme ends of travel of the bearing 28, may be used as limit switches for the purpose of limiting the travel of the bearing 28. Thus, these switches become actuated by the bearing 28 when the latter reaches its extreme ends of travel. The switches then deenergize the driving means for the threaded rod 31, so that the latter is stopped in place and the nut 30 is no longer urged along the threaded rod.

In conjunction with the angular adjustment of the roll 10, it is also possible to combine other adjustments with this angular orientation arrangement, shown in FIGS. 10 and 11. In FIG. 10, the central shaft 10a of the roll 10 has two portions 10b and 10c which include opposite threads. Thus, one portion on the shaft 10a has a left-handed thread, whereas the other portion has a right-handed thread. Threaded nuts 34 engage these threaded portions and carry a plurality of spindles or rods 35 which slide under the soft coating of the roll 10 at its central portion. The ends of the coating are integral with ball bearings 10d. One of these ball bearings is powered or driven. The drive for this adjustment ar rangement to be operative in conjunction with the angular adjustment for the roll 10, is designed to be independent of the rotation of the roll 10.

When the central shaft 10a is rotated, the nuts34 travel towards or away from the center of this shaft 10a, and the rods 35 push or pull, thereby, the coating or covering for the roll 10. As a result, this coating or covering undergoes an expansion or contraction in the transverse direction, and this varies the speed of the cloth over the roll. With such control variation in the speed of the cloth over the roll, it is possible to correct defects or deformations resulting from misalignment existing between the ends. Thus, the cloth can be correctly located at both ends, with this adjustment.

FIG. 11 illustrates an arrangement with an auxiliary feed roll in which the control over the retraction or expansion function is accomplished by nuts or rods in a non-symmetrical manner. In this arrangement, a female threaded nut 44 is arranged on one end of the shaft 10a on a threaded portion Me of this shaft. The threaded nut 44 is held fixed in the longitudinal or lateral direction and when this nut 44 is turned, the central shaft 10a is moved in the lateral direction, and this allows biasing of the feed roll at any point along its length.

Other mechanical systems may also be used for accomplishing the contraction or expansion functions, and a pneumatic arrangement may also be used in which suitable air control produces biasing of the entire or a portion of the length of the feed roll.

As illustrated in FIG. 12, 13 and 14, in accordance with the present invention, various designs are possible for achieving removal of deformations or wrinkling in the fabric or product being processed.

In FIG. 12, several rollers 41 are linked together so as to produce a biasing arrangement when functioning collectively or individually for the purpose of achieving the biasing object described above.

In FIG. 13 the driving device has essentially a series of rolls or rollers 42 lying substantially always on the general axis of rotation. These rollers 42, however, are deflectable by suitable means, not shown, and they are subject to driving at uniform speed or at varying speeds by, for example, a differential gear mechanism. With the formation of two facing split cones, as shown in the illustrated example of FIG. 13, defects in the fabric or material being processed may be corrected at the central part thereof.

FIG. 14 shows an assembly of rollers 43 which are joined together but are individually deflectable in the transverse direction. In the two rollers shown in the drawing of FIG. 14, one has the shape or outline of a barrel-shaped element, whereas the other roller exhibits a concave profile in which the central portion is narrowed down, so that the diameters increase from the central part of this roller towards the ends of this roller. This arrangement of the design of rollers 43 allows for adjustment of straightness or alignment of the fabric or material being processed, while being either wound or unwound or moving in either direction.

FIGS. 1, 2 and 5 show embodiments which include arrangements for stopping the carrier 2 at the instant of cutting for the purpose of forming substantially perfectly superimposed stacks or pads of sheets of cloth or fabric on the operative run of the carrier. A system of adjustable stops has been provided for this purpose in such arrangements for stopping the carrier in place. Thus, an adjustable stop 37 may be set in place by means of a threaded arrangement. 36 attached to the table 1. The stop 37 has a cylindrical outer surface which is in contact with a follower stem or element 38a of a switching contact 38. This switching contact 38 is, in turn, attached to the carrier 2.

It is essential to note that during the return or inoperative motion or stroke of the carrier, the switching contact must not contact the stop 37. To remove the switching contact from the path of the stop, a geared handle 39 is provided, for example, which may be either manually or automatically actuated for this purpose.

The arrangement, in accordance with the present invention, may be adapted to every kind of strip-goods handling machines. When processing check-patterns which have been substantially perfectly wound up, these materials can then be used directly upon unwinding, without resorting to adjustments for straightness or other line orientations.

Without further analysis, the foregoing will solefully reveal the gist of the present invention that others can,

by applying current knowledge, readily adapted for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. An arrangement for predetermined aligning of sheet material while being processed comprising, in combination, a roll member over which said sheet material passes while being rolled up and unrolled; an adjustment means connected to said roll member for adjusting the disposition of said roll member to align said sheet material in predetermined direction for processing said sheet material substantially free of wrinkles, said roll member comprises a plurality of parts operable at variable speeds for varying the speed of motion of said sheet material at predetermined locations on said sheet material while being rolled and unrolled.

2. An arrangement for predetermined aligning of sheet material while being processed comprising, in combination, a roll member over which said sheet material passes while being rolled up and unrolled; an adjustment means connected to said roll member for adjusting the disposition of said roll member to align said sheet material in predetermined direction for processing said sheet material substantially free of wrinkles; means for expanding and contracting said roll member diametrically for varying the speed of motion of said sheet material at predetermined locations on said sheet material.

3. The arrangement as defined in claim 2 wherein said means for expanding and contracting said roll member diametrically comprising a shaft member through the central portion of said roll member and having two oppositely threaded portions; femalethreaded members engaging said threaded portions of said shaft member and moving in opposite directions upon rotation of said shaft member; and a plurality of rod members carried by said female-threaded members for contacting the periphery of said roll member and thereby varying the effective diameter of said roll member at predetermined locations along the longitudinal axis of said roll member, said contraction and expansion of said roll member being symmetrical along the length of said roll member.

4. The arrangement as defined in claim 3 including a threaded portion at one end of said shaft member; a female-threaded positioning member in contact with said threaded portion at said one end of said shaft member, the rotation of said positioning femalethreaded member displacing said shaft member along the longitudinal axis of said shaft member for expanding and contracting said roll member asymmetrically.

5. The arrangement as defined in claim 2 wherein said means for expanding and contracting said roll member comprises Archimedean screws and rod-frame rings.

6. The arrangement as defined in claim 2 wherein said means for expanding and contracting said roll member comprises pneumatic control means.

7. An arrangement for predetermined aligning of sheet material while being processed comprising, in combination, a roll member over which said sheet material passes while being rolled up and unrolled; an adjustment means connected to said roll member for adjusting the disposition of said roll member to align said sheet material in predetermined direction for processing said sheet material substantially free of wrinkles, said adjustment means comprises a source of light; a casing surrounding said source of light and having an adjustable aperture through which light from said source is emitted; and an elongated member in the path of said light transmitted through said aperture for projecting onto said sheet material a line image in predetermined direction to the motion of said sheet material.

8. The arrangement as defined in claim 7 wherein said source of light is mounted on a predetermined side of said sheet material.

9. The arrangement as defined in claim 8 wherein said sheet material has starting lines along predetermined lengths of said sheet material, said light images being shadows cast onto each starting line of said sheet material.

it). The arrangement as defined in claim 9 including means for adjusting said aperture and casting line shadows on a plurality of predetermined locations on said sheet material.

11. An arrangement for predetermined aligning of sheet material while being processed comprising, in combination, a roll member over which said sheet material passes while being rolled up and unrolled; and adjustment means connected to said roll member for adjusting the disposition of said roll member to align said sheet material in predetermined direction for processing said sheet material substantially free of wrinkles; cutting carrier means supporting said adjustment means; inspection table means along which said cutting carrier means is slidable, said inspection table having stacked thereon predetermined cut lengths of said sheet material after cutting by said cutting carrier means.

12. The arrangement as defined in claim 11 including stop means along one side of said table for stopping said carrier for cutting said sheet material; switch means attached to said carrier means and contacting said stop means for applying an electrical signal to stop said carrier means in predetermined position.

13. The arrangement as defined in claim 12 including means for moving said switch means out of the path of said stop means when said carrier means moves in the return inoperative direction.

14. An arrangement for predetermined aligning of sheet material while being processed comprising, in combination, a feed roll member over which said sheet material passes while being rolled up and unrolled; an adjustment means connected to said roll member for adjusting the disposition of said roll member to align said sheet material in predetermined direction for processing said sheet material substantially free of wrinkles; and cutting means for cutting said sheet material into predetermined cut lengths of material for stacking, said sheet material having at least one transverse reference line for aligning said cut lengths in predetermined relationship when stacked.

15. The arrangement as defined in claim 14 including means at one end of said roll member for displacing said one end to orient said roll member in predetermined angular position; driving means linked to the other end of said roll member for driving said roll memher while in said predetermined angular position, said roll member being a one-piece integral member.

16. The arrangement as defined in claim 15 including.

joint means linking said drive means to said roll member, said joint means comprising a sleeve member on said roll member and a pivot stud element passing through said sleeve member and said roll member.

17. The arrangement as defined in claim 15 wherein said means for orienting said roll member in predetermined angular position comprises a threaded rod; a female-threaded member engaging said threaded rod and having a horizontally connected bearing in which said roll member is slidable.

Claims

3. The arrangement as defined in claim 2 wherein said means for expanding and contracting said roll member diametrically comprising a shaft member through the central portion of said roll member and having two oppositely threaded portions; female-threaded members engaging said threaded portions of said shaft member and moving in opposite directions upon rotation of said shaft member; and a plurality of rod members carried by said female-threaded members for contacting the periphery of said roll member and thereby varying the effectiVe diameter of said roll member at predetermined locations along the longitudinal axis of said roll member, said contraction and expansion of said roll member being symmetrical along the length of said roll member.

4. The arrangement as defined in claim 3 including a threaded portion at one end of said shaft member; a female-threaded positioning member in contact with said threaded portion at said one end of said shaft member, the rotation of said positioning female-threaded member displacing said shaft member along the longitudinal axis of said shaft member for expanding and contracting said roll member asymmetrically.

10. The arrangement as defined in claim 9 including means for adjusting said aperture and casting line shadows on a plurality of predetermined locations on said sheet material.

15. The arrangement as defined in claim 14 including means at one end of said roll member for displacing said one end to orient said roll member in predetermined angular position; driving means linked to the other end of said roll member for driving said roll member while in said predetermined angular position, said roll member being a one-piece integral member.

16. The arrangement as defined in claim 15 including joint means linking said drive means to said roll member, said joint means comprising a sleeve member on said roll member and a pivot stud element passing through said sleeve member and said roll member.

18. The arrangement as defined in claim 17 including bearing block means supporting said threaded rod and horizontally movable for imparting said predetermined angular position to said roll member.

19. The arrangement as defined in claim 15 including means for limiting the angular orientation of said roll member.

20. The arrangement has defined in claim 11 including an adjustable source of light carried on a frame integral with said table; an elongated member in the path of said light for casting an intense shadow onto said table.