GB2145038A - Document display apparatus - Google Patents

Abstract

A copyholder has a cursor for assisting document transcription. The cursor is driven by a drive belt 14, via a drive peg and thence a mounting block 22 to which the cursor is fixed. The block 22 is slidable on a guide rod 24 secured on the copyholder by leaf springs 26. To change a document the cursor is swung from the display face, as shown. An abutment on the block 22 engages the rear face of the copyholder, moving the rod 24 rearwardly against an increasing spring force, and disengaging the peg from the belt 14. The cursor is stable in the position shown but the return movement is assisted by the springs and as they relax the peg re-engages the belt 14. Cursor control means controlling the stepwise movement of the cursor may comprise a light sensitive sensor moving with the cursor, and reading a program bar 42 which has light and dark markings representing the required line spacing. The user operates a switch to drive the cursor, and a signal from the sensor interrupts the drive when the cursor has been driven through one line spacing. <IMAGE>

Description

SPECIFICATION Document display apparatus This invention relates to display apparatus of the type commonly known as a copyholder, used to facilitate the accurate reading of documents to be transcribed.

According to a first aspect of the invention there is provided a copyholder comprising: a copyholder body having a display face; a transverse cursor; a guide rod extending along the length of the copyholder body to guide the cursor, the guide rod being fixed to the copyholder body by resilient means for urging the guide rod generally perpendicularly to its axis; a drive belt extending along the length of the copyholder body; and peg means connected to the cursor and engaged with the drive belt, in the reading position of the cursor;; wherein the cursor may be swung about the guide rod from its reading position to a paperchanging position in which it does not lie across the display face, the movement being accompanied by the disengagement of the peg means from the drive belt and the movement of the guide rod perpendicular to its axis, whereby the bias of the resilient means on the guide rod is altered.

Preferably the cursor is pivotable about the peg means, the movement of the cursor about the guide rod not being accompanied by the peg means, and the movement of the guide rod lifting the peg means out of engagement with the drive belt.

In a preferred embodiment the resilient means is relaxed in the reading position.

Preferably, when the cursor is swung from its reading position towards its paper-changing position an abutment face engages the copyholder body, causing the guide rod to move away from the copyholder body, agains the bias developed by the resilient means, the reaction at the abutment face balancing the resilient bias in the paper-changing position of the cursor. The resilient means may conveniently comprise a leaf spring at each end of the guide rod. The guide rod is preferably disposed on the rear side of the copyholder body, adjacent the edge thereof.

The peg means may have an aperture through which the guide rod passes. The peg means preferably comprises an L-shaped portion, one arm of said portion being engagable with the drive belt and the other arm being disposed alongside an edge face of the copyholder body.

In one embodiment of the copyholder the cursor is fixed at one end to a mounting member through which the guide rod passes, the movement of the peg means being transmitted to the cursor through the mounting member.

According to a second aspect of the invention there is provided a copyholder comprising: a display face against which a document to be read can be held; a transverse cursor; drive means to drive the cursor over the display face; a program bar disposed parallel to the direction in which the cursor is driven by the drive belt, the program bar carrying information representing the line spacing of the document to be read; and a sensor mechanically connected to the cursor and movable therewith, the sensor being arranged to detect the information carried by the program bar; whereby the drive means can drive the cursor in steps determined by the program bar.

Preferably the program bar is interchangable with other program bars carrying information of the line spacing of different documents to be read.

The copyholder according to the second aspect of the invention may further comprise a mechanically operable switch to actuate the drive means to drive the cursor, the cursor being driven until the drive means is arrested in response to a signal from the sensor.

The copyholder advantageously incorporates a DC motor, connected to the mains supply through an external transformer. Thus the apparatus is easily usable with different mains supplies. The DC motor can be used to drive the cursor up and down the display face, as required.

The invention will now be further described, by way of example, with reference to Figs. 1 to 4 of the accompanying drawings, in which: Figure 1 is a perspective front view of a copyholder embodying features of the invention; Figure 2 is a perspective rear view of the copyholder of Fig. 1; Figure 3 is a detailed perspective view in partial cutaway of cursor control and drive apparatus, the cursor being in its reading position against the display face of the copyholder; and Figure 4 is a view of Fig. 3 but with the cursor in its paper-changing position.

As is shown in Fig. 1, the copyholder has a display face 2 across which a cursor 4 extends. The cursor 4 may be driven up and down the display face and facilitates the accurate reading of a document on the face 2.

Such a document on the display face and is held by a retaining bar 8 at the top end of the face.

The copyholder rests, in use, on a retractable stand bar 10, which may be locked in place by means of a clamping arm 1 2 projecting from the rear of the copyholder.

The drive mechanism for the cursor 4 will now be described with reference to Figs. 2 and 3. The cursor 4 is driven up and down the copyholder through the movement of a toothed, endless drive belt 14, disposed on the rear side of the copyholder, adjacent the copyholder edge face 16, and extending between pulleys 1 8 at the top and bottom of the copyholder. The belt 14 is driven through one of the pulleys 18, by a DC motor, the copyholder being connectable to the mains supply through an external transformer via an input socket 20 on the rear side of the copyholder.

The cursor 4 is fixed to a mounting member 22 by means of a clamping knob 23. The mounting member 22 is disposed, when the cursor 4 is in its reading position across the display face, adjacent the edge face 1 6. The mounting member 22 is formed with a bore, through which passes a guide rod 24. The mounting member 22 is slidable on and pivotable about the guide rod 24. The guide rod 24 is disposed between the edge face 16 and the drive belt 14, and extends along the length of the copyholder to positively guide the mounting member and cursor. The guide rod 24 is mounted at each end by a leaf spring 26, the leaf springs being relaxed in the reading position shown in Fig. 3.

The movement of the drive belt 14 is transmitted to the mounting member 22 and cursor 4 through a peg 27. The peg 27 is generally L-shaped (see Fig. 4), one arm 28 of the peg engaging, in the reading position of the apparatus, the drive belt 14 and the other arm 30 being disposed adjacent edge face 1 6. The corner of the L is formed with an aperture through which the guide rod 24 passes, the peg being freely mounted on the rod. The peg passes through a recess 31 formed in the wall of the mounting member, and the mounting member and peg 27 are free to pivot about each other.

It will be apparent that when the belt 14 is driven, the peg 27 moves with it, drawing the mounting member 22 and hence the cursor 4. The cursor 4 may be driven in either direction, as the user requires.

When the document on the display face is to be changed the cursor is swung to the paper-changing position shown in Figs. 2 and 4, in which it does not lie across the display face. When the cursor is so swung the mounting member 22 pivots about the guide rod 24 and moves away from the edge face 1 6. The peg 27 does not so pivot, being a loose fit in the recess 31 in the wall of the mounting member.

As will be noted from a comparison of Figs.

3 and 4, when the cursor is swung to the paper-changing position the guide rod 24, and hence the attached peg 27, mounting member 22 and cursor 4, move rearwards from their reading to their paper-changing position, by a sufficient distance to disengage the peg 27 from the drive belt 14. As the cursor is swung away from the display face an angled extension or abutment portion 32 on the mounting member 22 adjacent the guide rod 24 engages the rear face 34 of the copyholder. As the swinging movement is continued the guide rod is pushed away from the rear face and the springs 26 are stressed.

In the fully swung open position of Fig. 4 the forward force on the guide rod 24 provided by the springs 26 is balanced by the rearwards force acting on it through the mounting member, arising as a result of the engagement of the extension 32 with the rear face 34.

When the document has been changed the cursor 4 may be swung back into its reading position. The leaf springs 26 relax, and the guide rod 24, peg 27 and their connected parts move forwards. The peg 27 engages the drive belt and the cursor may be driven as before.

The return movement outlined above is easily accomplished. When the movement begins the abutment face 32 slips from its metastable position on the copyholder rear face 34.

The springs 26 urge the guide rod 24 forwards and as the rod moves under the bias the continuing but sliding contact between the abutment face 32 and the rear face 34 causes the mounting member 22, and hence the cursor 4, to be pivoted towards their reading positions.

Cursor position control apparatus will now be described with reference to Figs. 3 and 4.

As is shown in these figures, the copyholder further comprises a program bar or strip 36 and a photosensitive sensor 38. The bar 36 is parallel to the guide rod 24 and extends along the length of the copyholder. It is securely retained in a C-section longitudinal housing 40 and has a tab 42 which projects from the top of the copyholder to enable the bar to be withdrawn from the carrier. The bar is marked with alternate light and dark markings, successive identical markings being separated by the line spacing of the document to be read.

The sensor 38 faces the opening 44 in the Csection bar housing 40 and hence the program bar 36.

The photosensitive sensor 38 is rigidly mounted on a sensor carrier 46 which is itself slidably mounted on a carrier plate 48. The carrier 46 is rigidly fixed in transverse alignment with the mounting member 22 and cursor 4 by means of two spaced transverse guide rails 50 each fixed at one end to the sensor carrier 46 and being looped around the guide rod 24 at their other end, one contacting the upper face 52, and the other contacting the lower face 54, of the mounting member 22. Thus, when the cursor 4 is driven up and down the display face the movement is transmitted to the sensor carrier 46 through the upper and lower guide rails 50.

The apparatus controls the sensor position as follows. A program bar 36 carrying information representing the line spacing of the document to be read is inserted in the bar housing 40. The user can raise or lower the cursor by operating the appropriate control of a simple switch, for example, a footswitch, or a handswitch attached to a typewriter keyboard, connected to the copyholder through an input 56 on the rear side 34 thereof. The movement of the cursor is terminated when a signal from the sensor 38 switches off the motor, in accordance with the information on the program bar 36, i.e. after the cursor has moved one line spacing.

When the document has been transcribed the cursor is again swung off the display face and a new document can be positioned on it.

The cursor is returned to the reading position and can then be returned to the top of the copyholder by running the DC motor in the appropriate direction. A switch 58 may be provided on the copyholder to assist the return movement. When the switch 58 is in one position the operation of the foot or handswitch causes the cursor to move line by line as described above. When the switch 58 is in its second position the program bar is overridden and use of the foot or handswitch causes the cursor to be driven continuously. Thus the cursor can be readily returned to the top of the display face.

If a program bar cannot conveniently be made for a particular document to be read the switch 58 may be kept in its second position and the foot or handswitch depressed a sufficient time for the cursor to be moved to the next line to be read. Thus the hand or footswitch can be used to control the stepping of the cursor, instead of the program bar.

When the line spacing of a new document to be read differs from that of the old one the old program bar 36 is removed and new one, with markings corresponding to the line spacing of the new document, inserted with the bar housing 40. The bar could readily be made up by the user if the line spacing of the document were not standard.

By using a DC motor with an external transformer the copyholder can be readily used with different mains supplies. Naturally in alternative embodiments a DC motor could be used downstream of an internal transformer, or an AC motor could be used, although a DC motor has the advantage of being able to drive the belt in both directions. Thus. a DC motor can return the cursor to the top of the display face when the bottom of a page has been reached.

Claims (9)

1. A copyholder comprising: a copyholder body having a display face; a cursor having a reading position in which it extends across the display face; a guide rod extending along the length of the copyholder body and mounted thereon by a resilient mounting for urging the guide rod transversely to its axis, the cursor being mounted on the guide rod for movement along it; a drive belt extending along the length of the copyholder body; and a drive peg connected to the cursor, the drive peg being engaged with the drive belt- in the reading position of the cursor;; wherein the cursor may be swung about the guide rod from the reading position to a paper-changing position in which it does not lie across the display face, the movement of the cursor above the guide rod resulting in the movement of the guide rod transverse to its axis and in the disengagement of the drive peg from the drive belt.

2. A copyholder according to claim 1 wherein when the cursor is swung from its reading position to its paper-changing position an abutment face defined on the cursor or on a part secured thereto engages the copyholder body, causing the guide rode to move away from the copyholder body, against an increasing bias being developed by the resilient means, the reaction at the abutment face balancing the resilient bias in the paperchanging position of the cursor to retain the cursor in that position.

3. A copyholder according to claim 1 or 2 wherein the drive peg is mounted on the guide rod and is so connected to the cursor that it does not swing about the guide rod when the cursor swings from its reading to its paper-changing position, and wherein the movement of the guide rod lifts the drive peg out of engagement with the drive belt.

4. A copyholder according to any preceding claim wherein the resilient mounting comprises a leaf spring at each end of the guide rod.

5. A copyholder according to any preceding claim wherein the cursor is carried by a mounting member which is slidable on the guide rod, the mounting member being coupled to the drive peg such that movement of the drive belt causes the mounting member to move along the guide rod, and the mounting member being able to swing about the guide rod and with respect to the drive peg.

6. A copyholder according to any preceding claim, further provided with cursor control means which comprises a program bar disposed parallel to the direction in which the cursor is driven by the drive belt, the program bar carrying information representing the line spacing of the document to be read, and a sensor connected to the cursor for movement therewith, the sensor being arranged to detect the information carried by the program bar and to relay an interrupting signal to a motor driving the drive belt when the motor has driven the cursor through one line spacing.

7. A copyholder according to claim 6 wherein the program bar is removably retained in the copyholder body, whereby it may be removed and replaced by another program bar representing a different line spacing.

8. A copyholder according to claim 7, further comprising override means to override the cursor control means, whereby the cursor may be driven continuously over the display face.

9. A copyholder substantially as hereinbefore described with reference to the accompanying drawings.