CHART HOLDER
United States Patent 3659368
An index charge holder in which a plurality of indexed cards are clamped to a supporting base and a cover is provided pivotally connected to the clamping means. The cards have keyed cutaway edges and a slider is disposed on the cover having an inwardly extending portion beneath the cover adapted for selective coaction with the cutaway card edges, so that when the cover is raised, a selected quantity of the cards are lifted therewith. The upper portions of the cards are secured to the base independent of the clamping means and a plurality of sheets are disposed between the indexed cards secured by the clamping means, but otherwise unsecured so that they may be removed upon opening of the clamping means. The cover is formed to pivotally swing onto the clamping means for levered opening thereof.
US Patent References:
Loose-leaf binder
Conrad - November 1929 - 1734898
Index device
Faas - February 1944 - 2341983
Loose-leaf binder
Hazel - June 1949 - 2472898
List finder
Lang - September 1955 - 2717605
ELECTROMOTOR CONSTRUCTION
Bolzoni - March 1957 - 3786290
Loose-leaf binder
Conrad - November 1929 - 1734898
Index device
Faas - February 1944 - 2341983
Loose-leaf binder
Hazel - June 1949 - 2472898
List finder
Lang - September 1955 - 2717605
ELECTROMOTOR CONSTRUCTION
Bolzoni - March 1957 - 3786290
Application Number:
04/854211
Publication Date:
05/02/1972
Filing Date:
08/29/1969
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
462/78, 402/69, 281/45
International Classes:
B42F17/34; B42F17/00; G09F11/06
Field of Search:
40/104.01 402/69 24/67.5,67.7 281/45 282/29B
US Patent References:
Primary Examiner:
Michell, Robert W.
Assistant Examiner:
Oremland L. R.
Claims:
I claim
1. An index, comprising:
2. The invention according to claim 1 in which said clamping means comprises a member formed rearwardly with a spring loaded pivot and pivotally connected forwardly to said cover whereby said cover can pivotally swing onto said clamp member for levered opening of said clamping means.
3. The invention according to claim 1 in which said cards have keyed cutaway edges and said lifting means comprises a slider on said cover having an inwardly extending portion beneath said cover adapted for selective coaction with said cutaway card edges.
4. The invention according to claim 1 including means for latching said cover in a closed position.
5. The invention according to claim 1 including a resiliently deformable member between said cover and base and formed to deform upon closure of said cover to urge said cover to an open position.
6. The invention according to claim 1, including a transparent member supported by and spaced from the top of said clamp means and formed for insertion therein of identifying material.
1. An index, comprising:
2. The invention according to claim 1 in which said clamping means comprises a member formed rearwardly with a spring loaded pivot and pivotally connected forwardly to said cover whereby said cover can pivotally swing onto said clamp member for levered opening of said clamping means.
3. The invention according to claim 1 in which said cards have keyed cutaway edges and said lifting means comprises a slider on said cover having an inwardly extending portion beneath said cover adapted for selective coaction with said cutaway card edges.
4. The invention according to claim 1 including means for latching said cover in a closed position.
5. The invention according to claim 1 including a resiliently deformable member between said cover and base and formed to deform upon closure of said cover to urge said cover to an open position.
6. The invention according to claim 1, including a transparent member supported by and spaced from the top of said clamp means and formed for insertion therein of identifying material.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of art to which the invention pertains includes the field of hinged leaf indices.
2. Description of the Prior Art
Chart holders of the general type herein are used to secure together a plurality of sheets of paper for ready reference and for ready removal of one or more sheets. Such chart holders have a clamping member on the top thereof and a cover pivotally connected to the clamping member overlying the sheets for protection. In a variety of situations, it is desirable to separate sheets so secured by means of indexed cards whereupon one can select a particular group of sheets upon which some item of information if to be recorded, without disturbing other groupings of sheets. With prior chart holders, where such an arrangement is attempted, it is generally found that replacement of individual sheets or small groups of sheets is awkward. It is also desirable to enable ready reference to a particular group of sheets without thumbing through all preceding sheets and to obtain ready access to a selected grouping of sheets with a minimum of manipulation.
SUMMARY OF THE INVENTION
The present invention provides a chart holder in which a plurality of cards are clamped to a base and a cover is provided pivotally connected to the clamping means. In one embodiment, means are provided in addition to the clamping means for securing the upper portions of the cards to the base and a plurality of sheets are disposed between the cards in a desired organization and secured thereat by the clamping means, but unsecured by the additional securing means. By such an arrangement, upon opening the clamping means, selected sheets may be removed without removing the cards which are secured independent of the clamping means.
In other embodiments, means are provided for lifting a selected quantity of the cards in company with the cover when the cover is raised. This is accomplished by providing the cards with keyed cutaway edges and by providing a slider on the cover having an inwardly extending portion beneath the cover adapted to selectively coact with the cutaway card edges.
Levered opening of the clamping means is effected by backward movement of the cover. Means are provided for latching the cover into a closed position over a resiliently deformable member whereby upon release of the latch, the deformable member urges the cover to an open position. In still further embodiments, a transparent member is supported by and spaced from the top of the clamp for insertion therein of identifying material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a chart holder incorporating the improvements herein, and shown in a closed position;
FIG. 2 is a perspective view of a number of indexed cards utilized in the chart holder of FIG. 1 along with a securing member shown in exploded relation to the cards;
FIG. 3 is a sectional view taken on the line 3--3 of FIG. 1, in the direction of the arrows;
FIG. 4 is a cross sectional view similar to that of FIG. 3, except that the cover is shown in an open position;
FIG. 5 is a cross sectional view similar to that of FIGS. 3 and 4 except that the cover is shown moved backwardly and downwardly to open the clamp by lever action;
FIG. 6 is an enlarged fragmentary sectional view taken on the line 6--6 of FIG. 3; and
FIG. 7 is a fragmentary perspective and partially exploded view of the slider and rail utilized herein, along with a portion of the chart holder base.
DETAILED DESCRIPTION
Referring to FIGS. 1-3, the chart holder 10 comprises a rectangularly shaped flat base 12 formed at its uppermost end 14 with a clamp member 16. The base 12 and clamp member 16 can be formed integrally of the same material as shown, e.g., of sheet metal, plastic, or other suitable material, or the clamp member 16 can constitute a separate member fixedly secured to the base by some means. To provide additional clamping action, the clamp member 16 can be provided with a plurality of spring-loaded fingers 18. A steel rod 20 can be disposed through the curved fingers 18 and rigidly secured to the base at 22 (FIG. 3) by welding or by other means, and a number of helical springs 24 secured on the rod with spacers 21. Each spring 24 has an arm 26 overlying the top surface of the clamp 16 and bearing downwardly thereon.
A cover member 28 is hingedly connected at 30 to the lower edge of the clamp member 18, and the cover 28 may also be formed of metal, plastic or other suitable material. The pivoted or hinged cover member 28 includes a flat, relatively narrow upper portion 32 and a rectangular box-shaped lower portion 34 defined by sidewalls 36 and 38, a front wall 40, a rear wall 42, and a top wall 44. The cover 28 is formed with this configuration so as to house an indexing mechanism as hereinafter described.
Referring particularly to FIGS. 2 and 3, and additionally to FIG. 6, a plurality of index cards 46a, 46b, 46c, etc., are disposed between the base 12 and the clamp 18 and cover 28. Any reasonable number of cards can be utilized and the particular numbers depicted in the drawings are for illustrative purposes only. Generally, about 10 such index cards 46 are conveniently utilized, but for clarity, only three cards have been shown in FIG. 2 and six cards in FIG. 6. Between adjacent index cards 46 there are disposed a varying number of generally thinner sheets 48 (shown mostly in shadow in FIG. 2). Referring specifically to FIG. 6, the number of such sheets can vary from zero between any two particular cards 46 and 10 or more between other cards 46, or whatever reasonable number is desired and can be accommodated by the geometry of the chart holder. The sheets 48 are generally quite a bit more flexible than the relatively thicker card members 46 and are narrower in width and shorter in length so as to fit therebetween. It is contemplated that the cards 46 will serve as index cards to enable rapid location of the sheets 48 which sheets will serve for recording data or for presenting information which is not required to be permanently bound.
Referring specifically to FIG. 2 in conjunction with FIG. 3, the base 12 defines a pair of apertures 50 therethrough for receiving the prongs 52 and 54 of a U-shaped fastening member 56. The index cards 46 are formed along their top edge with a pair of apertures 58 and 60 through which the prongs 52 and 54 pass prior to engagement within the base apertures 50. By such means, the index cards 46 are fixedly secured to the base 12 along their top edge. Importantly, the chart sheets 48 are disposed between the index cards 46 so that their top edges 62 fall short of extending beneath the index card apertures 58 and 60 so that they are not fixed in position by the pronged member 56. However, they are clamped in position by action of the clamping member 16, reinforced by the spring arms 26, along a line spaced downwardly from the top edge of the index cards 46 (shown in shadow at 64), and it is along this line that the cover 28 is hingedly secured, at 30, to the clamp member 16.
Accordingly, both the sheets 48 and index cards 46 are tightly clamped to the board 12 and remain clamped when the cover 28 is raised. This is illustrated with reference to FIG. 4 where it is seen that simple raising of the cover member 28 does not result in an unclamping of the clamp member 16. However, and with reference to FIG. 5, if one continues to move the cover 28 rearwardly, the edge 66 between the rear and top walls 42 and 44 contact the top of the clamp member 16. Further rearward and downward movement, as indicated by the arrow 68, effects a lever action to open the clamp 16. With the clamp 16 thus open, one can readily remove any desired sheet 48, as indicated by the arrow 70, without disturbing the card members 46 since they remain secured by the pronged fastener 56.
As will hereinafter be described in more detail, a selected number of the card members 46 and interspersed sheet member 48 are lifted with the cover 28 by means of an index selector mechanism. The particular member 48 shown as being withdrawn is a remaining top member following such index selection; however, any subsequent sheet member 48, located between subsequent card members 46, may be withdrawn by simply manually lifting both card members 46 to the desired sheet member 48 and removing the sheet member 48, the card members being retained by the pronged fastener 56, as described. In other words, while the present embodiment incorporates an index selector, the double grip action obtained by the use of both a yielding clamp 16 and unyielding fastener 56 operates advantageously independently of the index selector. On the other hand, by providing an index selector, clear advantages accure in the utilization of the chart holder in that it is much easier to manipulate and to add and remove sheets, as will now be described in more detail.
Referring now to the index selector mechanism, and specifically to FIG. 7 in conjunction with FIGS. 3-5, the mechanism comprises a guide rail 72 which is provided with threaded apertures 74, one on each end, and which is secured along the inside of a sidewall 36 of the cover 28 by means of machine screws 76 and inside washers 78 to space the guide rail 72 from the sidewall 36. Referring additionally to FIGS. 1 and 2, the plurality of index cards 46 are provided with keyed cutaway edges 80 which are indexed to correspond with a tabulation 82 (FIG. 1) printed on the top of the cover.
A slider 84 is provided with means for slidably securing it to the guide rail 72 in the form of slotted side flanges 86. The slider 84 is provided with a thin neck portion 88 extending upwardly through an elongate slot 90 defined through the top cover wall 44 along the sidewall 36 edge, and the neck portion 88 is provided with an inwardly extending pointer or indicator 92. The slider 84 also has a lower inwardly extending portion or selector 94 which is adapted to slide within an elongate recessed track 96 formed along that edge of the base 12 and is adapted for selective coaction with the cutaway edges of the index cards 46. When the cover 28 is closed, the selector 94 lies at a level slightly below the bottom index card 46, in the track 96 so that the selector 94 may slide freely underneath the edges of the cards without interference. An additional, inwardly extending portion 98 may be provided so as to sandwich selected cards 46 between the members 94 and 98 for smoother retention thereof.
The pointer 92 is adapted to cooperate with the index 82 printed on the top of the cover 28 which may be any appropriate designation such as the letters of the alphabet, or, as illustrated, particular heading designations. The cards 46 may also bear the index characters, as illustrated at 100 (FIG. 2), which from the top to the bottom of the stack of cards corresponds to the designations of the index 82. The slider 84 is yieldingly and releasably held in adjusted position by means of an indentation thereon (not shown) in detent relationship with an appropriate aperture 102 drilled through the guide rail 72.
Referring now to FIGS. 1, 3 and 4, the lowermost portion 104 of the base 12 can extend somewhat beyond the cover 28 and can be provided centrally thereof, or in other appropriate place with a latching member 106. The latching member is secured by a flat spring 108 to the underside of the base 12 within a cavity 110 therefor, and is provided with a notch 112 along its top edge to mate with and secure a lip 114 formed along the forward bottom end of the front cover wall 40. When in a closed position, as shown in FIG. 3, the cover 28 is latched by the latching member 106, which when moved downwardly against the force of the flat spring 108 releases the cover 28 whereupon the cover 28 may be raised, manually or by a spring mechanism, as desired. One such spring mechanism is indicated in shadow in FIG. 4 wherein a flat spring 116 is secured along the top edge of the cover wall 38 and is formed so as to normally extend upwardly. Upon release of the latch 106, the spring 116 forces the cover member 28 upwardly away from the base 12 whereupon it may then be opened to the position shown in FIG. 4 by further manual movement. Alternatively, a spring mechanism may be adapted to completely open the cover 28. For example, a rod can be journaled across the top of the base 12 spaced from the sheets 48 and cards 46 as indicated in shadow at 118 in FIG. 4, and a helical spring 120 on each side thereof with arms 122 therefrom biasing the cover 28 upwardly along opposite sides of the cover. Clearance for the rod would be cut through the cover side walls 36 and 38.
Referring to both FIGS. 4 and 5, in operation, after a packet 124 of cards and sheets have been selected by the indexing member 84, that packet 124 remains lifted with the cover 28 even during removal of other sheets from the chart holder as illustrated in FIG. 5.
Referring now to a further feature of this invention, and with reference to FIGS. 1 and 3, an elongate transparent member 126 of U-shaped cross-section is disposed along the top of the clamp member 16 with its flat portion spaced slightly from the surface of the clamp member 16. By such means, one can insert identifying material, in the form of an elongate card in the slot 128 defined between the transparent member 126 and top surface of the clamp member 16.
1. Field of the Invention
The field of art to which the invention pertains includes the field of hinged leaf indices.
2. Description of the Prior Art
Chart holders of the general type herein are used to secure together a plurality of sheets of paper for ready reference and for ready removal of one or more sheets. Such chart holders have a clamping member on the top thereof and a cover pivotally connected to the clamping member overlying the sheets for protection. In a variety of situations, it is desirable to separate sheets so secured by means of indexed cards whereupon one can select a particular group of sheets upon which some item of information if to be recorded, without disturbing other groupings of sheets. With prior chart holders, where such an arrangement is attempted, it is generally found that replacement of individual sheets or small groups of sheets is awkward. It is also desirable to enable ready reference to a particular group of sheets without thumbing through all preceding sheets and to obtain ready access to a selected grouping of sheets with a minimum of manipulation.
SUMMARY OF THE INVENTION
The present invention provides a chart holder in which a plurality of cards are clamped to a base and a cover is provided pivotally connected to the clamping means. In one embodiment, means are provided in addition to the clamping means for securing the upper portions of the cards to the base and a plurality of sheets are disposed between the cards in a desired organization and secured thereat by the clamping means, but unsecured by the additional securing means. By such an arrangement, upon opening the clamping means, selected sheets may be removed without removing the cards which are secured independent of the clamping means.
In other embodiments, means are provided for lifting a selected quantity of the cards in company with the cover when the cover is raised. This is accomplished by providing the cards with keyed cutaway edges and by providing a slider on the cover having an inwardly extending portion beneath the cover adapted to selectively coact with the cutaway card edges.
Levered opening of the clamping means is effected by backward movement of the cover. Means are provided for latching the cover into a closed position over a resiliently deformable member whereby upon release of the latch, the deformable member urges the cover to an open position. In still further embodiments, a transparent member is supported by and spaced from the top of the clamp for insertion therein of identifying material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a chart holder incorporating the improvements herein, and shown in a closed position;
FIG. 2 is a perspective view of a number of indexed cards utilized in the chart holder of FIG. 1 along with a securing member shown in exploded relation to the cards;
FIG. 3 is a sectional view taken on the line 3--3 of FIG. 1, in the direction of the arrows;
FIG. 4 is a cross sectional view similar to that of FIG. 3, except that the cover is shown in an open position;
FIG. 5 is a cross sectional view similar to that of FIGS. 3 and 4 except that the cover is shown moved backwardly and downwardly to open the clamp by lever action;
FIG. 6 is an enlarged fragmentary sectional view taken on the line 6--6 of FIG. 3; and
FIG. 7 is a fragmentary perspective and partially exploded view of the slider and rail utilized herein, along with a portion of the chart holder base.
DETAILED DESCRIPTION
Referring to FIGS. 1-3, the chart holder 10 comprises a rectangularly shaped flat base 12 formed at its uppermost end 14 with a clamp member 16. The base 12 and clamp member 16 can be formed integrally of the same material as shown, e.g., of sheet metal, plastic, or other suitable material, or the clamp member 16 can constitute a separate member fixedly secured to the base by some means. To provide additional clamping action, the clamp member 16 can be provided with a plurality of spring-loaded fingers 18. A steel rod 20 can be disposed through the curved fingers 18 and rigidly secured to the base at 22 (FIG. 3) by welding or by other means, and a number of helical springs 24 secured on the rod with spacers 21. Each spring 24 has an arm 26 overlying the top surface of the clamp 16 and bearing downwardly thereon.
A cover member 28 is hingedly connected at 30 to the lower edge of the clamp member 18, and the cover 28 may also be formed of metal, plastic or other suitable material. The pivoted or hinged cover member 28 includes a flat, relatively narrow upper portion 32 and a rectangular box-shaped lower portion 34 defined by sidewalls 36 and 38, a front wall 40, a rear wall 42, and a top wall 44. The cover 28 is formed with this configuration so as to house an indexing mechanism as hereinafter described.
Referring particularly to FIGS. 2 and 3, and additionally to FIG. 6, a plurality of index cards 46a, 46b, 46c, etc., are disposed between the base 12 and the clamp 18 and cover 28. Any reasonable number of cards can be utilized and the particular numbers depicted in the drawings are for illustrative purposes only. Generally, about 10 such index cards 46 are conveniently utilized, but for clarity, only three cards have been shown in FIG. 2 and six cards in FIG. 6. Between adjacent index cards 46 there are disposed a varying number of generally thinner sheets 48 (shown mostly in shadow in FIG. 2). Referring specifically to FIG. 6, the number of such sheets can vary from zero between any two particular cards 46 and 10 or more between other cards 46, or whatever reasonable number is desired and can be accommodated by the geometry of the chart holder. The sheets 48 are generally quite a bit more flexible than the relatively thicker card members 46 and are narrower in width and shorter in length so as to fit therebetween. It is contemplated that the cards 46 will serve as index cards to enable rapid location of the sheets 48 which sheets will serve for recording data or for presenting information which is not required to be permanently bound.
Referring specifically to FIG. 2 in conjunction with FIG. 3, the base 12 defines a pair of apertures 50 therethrough for receiving the prongs 52 and 54 of a U-shaped fastening member 56. The index cards 46 are formed along their top edge with a pair of apertures 58 and 60 through which the prongs 52 and 54 pass prior to engagement within the base apertures 50. By such means, the index cards 46 are fixedly secured to the base 12 along their top edge. Importantly, the chart sheets 48 are disposed between the index cards 46 so that their top edges 62 fall short of extending beneath the index card apertures 58 and 60 so that they are not fixed in position by the pronged member 56. However, they are clamped in position by action of the clamping member 16, reinforced by the spring arms 26, along a line spaced downwardly from the top edge of the index cards 46 (shown in shadow at 64), and it is along this line that the cover 28 is hingedly secured, at 30, to the clamp member 16.
Accordingly, both the sheets 48 and index cards 46 are tightly clamped to the board 12 and remain clamped when the cover 28 is raised. This is illustrated with reference to FIG. 4 where it is seen that simple raising of the cover member 28 does not result in an unclamping of the clamp member 16. However, and with reference to FIG. 5, if one continues to move the cover 28 rearwardly, the edge 66 between the rear and top walls 42 and 44 contact the top of the clamp member 16. Further rearward and downward movement, as indicated by the arrow 68, effects a lever action to open the clamp 16. With the clamp 16 thus open, one can readily remove any desired sheet 48, as indicated by the arrow 70, without disturbing the card members 46 since they remain secured by the pronged fastener 56.
As will hereinafter be described in more detail, a selected number of the card members 46 and interspersed sheet member 48 are lifted with the cover 28 by means of an index selector mechanism. The particular member 48 shown as being withdrawn is a remaining top member following such index selection; however, any subsequent sheet member 48, located between subsequent card members 46, may be withdrawn by simply manually lifting both card members 46 to the desired sheet member 48 and removing the sheet member 48, the card members being retained by the pronged fastener 56, as described. In other words, while the present embodiment incorporates an index selector, the double grip action obtained by the use of both a yielding clamp 16 and unyielding fastener 56 operates advantageously independently of the index selector. On the other hand, by providing an index selector, clear advantages accure in the utilization of the chart holder in that it is much easier to manipulate and to add and remove sheets, as will now be described in more detail.
Referring now to the index selector mechanism, and specifically to FIG. 7 in conjunction with FIGS. 3-5, the mechanism comprises a guide rail 72 which is provided with threaded apertures 74, one on each end, and which is secured along the inside of a sidewall 36 of the cover 28 by means of machine screws 76 and inside washers 78 to space the guide rail 72 from the sidewall 36. Referring additionally to FIGS. 1 and 2, the plurality of index cards 46 are provided with keyed cutaway edges 80 which are indexed to correspond with a tabulation 82 (FIG. 1) printed on the top of the cover.
A slider 84 is provided with means for slidably securing it to the guide rail 72 in the form of slotted side flanges 86. The slider 84 is provided with a thin neck portion 88 extending upwardly through an elongate slot 90 defined through the top cover wall 44 along the sidewall 36 edge, and the neck portion 88 is provided with an inwardly extending pointer or indicator 92. The slider 84 also has a lower inwardly extending portion or selector 94 which is adapted to slide within an elongate recessed track 96 formed along that edge of the base 12 and is adapted for selective coaction with the cutaway edges of the index cards 46. When the cover 28 is closed, the selector 94 lies at a level slightly below the bottom index card 46, in the track 96 so that the selector 94 may slide freely underneath the edges of the cards without interference. An additional, inwardly extending portion 98 may be provided so as to sandwich selected cards 46 between the members 94 and 98 for smoother retention thereof.
The pointer 92 is adapted to cooperate with the index 82 printed on the top of the cover 28 which may be any appropriate designation such as the letters of the alphabet, or, as illustrated, particular heading designations. The cards 46 may also bear the index characters, as illustrated at 100 (FIG. 2), which from the top to the bottom of the stack of cards corresponds to the designations of the index 82. The slider 84 is yieldingly and releasably held in adjusted position by means of an indentation thereon (not shown) in detent relationship with an appropriate aperture 102 drilled through the guide rail 72.
Referring now to FIGS. 1, 3 and 4, the lowermost portion 104 of the base 12 can extend somewhat beyond the cover 28 and can be provided centrally thereof, or in other appropriate place with a latching member 106. The latching member is secured by a flat spring 108 to the underside of the base 12 within a cavity 110 therefor, and is provided with a notch 112 along its top edge to mate with and secure a lip 114 formed along the forward bottom end of the front cover wall 40. When in a closed position, as shown in FIG. 3, the cover 28 is latched by the latching member 106, which when moved downwardly against the force of the flat spring 108 releases the cover 28 whereupon the cover 28 may be raised, manually or by a spring mechanism, as desired. One such spring mechanism is indicated in shadow in FIG. 4 wherein a flat spring 116 is secured along the top edge of the cover wall 38 and is formed so as to normally extend upwardly. Upon release of the latch 106, the spring 116 forces the cover member 28 upwardly away from the base 12 whereupon it may then be opened to the position shown in FIG. 4 by further manual movement. Alternatively, a spring mechanism may be adapted to completely open the cover 28. For example, a rod can be journaled across the top of the base 12 spaced from the sheets 48 and cards 46 as indicated in shadow at 118 in FIG. 4, and a helical spring 120 on each side thereof with arms 122 therefrom biasing the cover 28 upwardly along opposite sides of the cover. Clearance for the rod would be cut through the cover side walls 36 and 38.
Referring to both FIGS. 4 and 5, in operation, after a packet 124 of cards and sheets have been selected by the indexing member 84, that packet 124 remains lifted with the cover 28 even during removal of other sheets from the chart holder as illustrated in FIG. 5.
Referring now to a further feature of this invention, and with reference to FIGS. 1 and 3, an elongate transparent member 126 of U-shaped cross-section is disposed along the top of the clamp member 16 with its flat portion spaced slightly from the surface of the clamp member 16. By such means, one can insert identifying material, in the form of an elongate card in the slot 128 defined between the transparent member 126 and top surface of the clamp member 16.