WO1995022784A1

WO1995022784A1 - Overhead projector presentation system

Info

Publication number: WO1995022784A1
Application number: PCT/CA1995/000095
Authority: WO
Inventors: George B. Blake
Original assignee: Blake George B
Priority date: 1994-02-22
Filing date: 1995-02-22
Publication date: 1995-08-24
Also published as: CA2116191A1

Abstract

A module for an overhead projector comprising a housing having one or more movable masks controlled by a manual or automatic control and having a highlight bar and a pointer.

Description

Title Of The Invention

OVERHEAD PROJECTOR PRESENTATION SYSTEM Technical Field

This invention relates to an improvement in an apparatus for visual display of text or graphics by projection of an image of same to a remote wall or screen. Background Art

Overhead projectors are a well known and commonly used device that permit a person to display text and graphics while making a presentation to a group. In general terms, such a projector may comprise a transparent plate adapted to support a transparent sheet substrate containing opaque text and graphics, a light source under the plate to direct light through the plate and such sheet to cast a shadow image of the text or graphics and a lens or prism to capture the image and to project it on a wall or screen for display. The simplicity of construction, the quality of image and ease of use make this kind of projector a very popular tool for presentations. Consequently overhead projectors are often found in businesses, schools, hotels, convention centres and the like.

While the simplicity of such apparatus makes it a popular presentation tool, the same simplicity also limits the ability of the user to control the presentation of material. For example, a sheet to be projected may contain material that a speaker would like to display in sections rather than all at once in order to focus the audience on each point being discussed. Conventional overhead projectors do not provide means to cover up part of a transparency so that often a speaker will improvise with a piece of paper or the like. Other problems include the blinding effect of the projection light when a speaker looks down at a transparency and the lack of suitable storage for transparencies before use.

It is an object of this invention to provide an apparatus to be fitted to an overhead projector to permit concealment of a portion or the whole of a transparency while the projection light is on, scrolling of a transparency, previewing of material without projecting it to the audience, and highlighting of specific points. Disclosure of Invention

The present invention is a apparatus to improve a standard overhead projector and includes an adjustable light mask to limit an image projected from a transparency, a highlight bar to emphasize a specific area of the image. The improvement may be made during manufacture of new projectors or by adapting an existing projector housing with additional elements, however, in embodiments discussed hereafter the invention is described in context of a module to be added to a projector. Construction of original equipment projectors or adaptation of existing projectors will be obvious to one skilled in the art having disclosure of the module. The module may be sized to fit directly on a conventional overhead projector to lie over its glass surface on which transparencies would normally be supported for projection. The usual size would be about 12" wide, 15" long and 1-7/8" high although it will be appreciated that the module may be built to accommodate other sizes. The module may be secured in place with brackets or other suitable fastening means, e.g., double sided adhesive strips or interconnecting hook strips (VELCRO™). The module has a perimeter frame supporting a transparent module plate over the glass plate of the projector thereby allowing projector light to pass through the frame to illuminate a transparency placed on the module plate. The frame also supports a film of light impeding material to shield all or part of a transparency from exposure under control of a user, The film is mounted within the frame to slide or roll forward or backward by operation of suitable manual or automatic control means.

In a preferred embodiment the film is mounted on a roller and attached to one or two continuous loop chains or belts supported on either side of the frame to move longitudinally on sprockets or pulleys (hereafter the invention is described in terms of chains and sprockets). The loop or the roller may be advanced or rotated under the influence of knobs, thumb wheels or the like. A quick action slide handle is also provided. (Hereafter handle is used as a general word to describe this element which may take many forms including a button, lug, grip, arm or lever). The chain loop rotates or advances loopwise (i.e., around the loop) on an idle sprocket located at one longitudinal end of the frame and a drive sprocket fixed to a trunnion of the film roller. The film roller trunnion is mounted in a bushing or bearing fixed to the opposing sides of the frame in bearing brackets.

User control of the film may be obtained by handles connected directly to the drive chains at a point near the connection of the film to the chain. The handles are mounted to slide in channels located on the sides of the frame over of the drive chains. A user may make large movements of the film by sliding the handles forward or backward. The handles are intended to be used primarily to return the film to the closed position at the end of each transparency. Fine control of the film movement may be obtained with a knob fixed to engage the shaft of the film roller. In a preferred embodiment a thumb wheel is mounted on the film roller shaft to extend through the module plate through apertures or slots therein. A user may direct movement of the film by rolling the thumb wheels forward or backward.

One or more highlight bars may be provided each comprising a tinted transparent strip (or even opaque strip for underlining) suspended transversely over the module plate and connected to a highlight handle positioned in a channel in the frame sides. In a preferred embodiment, a highlight handle may be located in the same channel as a the film handle. A highlight bar can be advanced when the film has been opened to expose a transparency to highlight a specific area of the transparency image being projected. Brief Description of Drawings In the Figures that illustrate a preferred embodiment of this invention:

FIGURE 1 is a plan view of a top cover, a handle, thumb wheel and highlight bar with pointer.

FIGURE 2 is an exploded perspective view of the preferred embodiment on a convention overhead projector, , FIGURE 3 is a front cross-sectional view showing a film, a film drive and film roller,

FIGURE 4 is a cross-sectional view of a right side, and

FIGURE 5 is a front cross-sectional view of the highlight bar device and pointer. Best Mode (or Modes) for Carrying Out the Invention

In the drawings that illustrate a preferred embodiment of this invention like numerals indicate like elements.

As shown in Figures 1 and 2 the module (1) of this invention fits over a glass plate

(10) of a conventional overhead projector (11) to provide a new transparent plate (25) to support a transparency (12). The module (1) is secured in place by a self-adhesive 1"

VELCRO™ strip (13) adhered to the top of the overhead projector structure (11) to correspond to a similar strip (14) adhered to the perimeter of the underside of the module (1).

The module has a rectangular supporting frame (20) with an "L" shaped cross section preferably constructed of thin sheet metal or plastic. The interior edge (21) of the base (22) of the frame (20) encircles the glass plate (10) of the projector (11). A cover plate (23) is hinged over the frame (20) by hinge (24) at the back of the module (1). The cover (23) may be similarly constructed of thin sheet metal or plastic corresponding to the module frame (20). The cover (23) supports a transparent plate (25), preferably glass or plastic, directly over the glass plate (10) of the overhead projector (11). A transparency (12) placed on plate (25) receives light from the overhead projector (11) which passes through the frame (20) and plate (25) to project an image onto a screen.

Control of the projected image is obtained with a film (26) beneath the plate (25). Film (26) is thin, flexible, opaque or semi-opaque material. As shown in Figures 2, 3 and 4, a leading film edge (27) is attached to continuous loop drive chains or belts (28) and (29) which run lengthwise along each lateral side of the module (1) in a plane approximately parallel to the plate (25). Bolts (30) and (31) fasten a bar (32) to the chains (28) and (29). The leading film edge (27) is fastened about the bar (32). Bar (32) is preferably made from thin sheet metal or transparent plastic. The other end of the film (26) is attached to a film roller (33) located at the front of the module (1) between the two drive chains (28) and (29). Each of chains (28) and (29) ride on sprockets (34) and (35) respectively, mounted on trunnions (36) and (37) of the film roller (33). The diameter of the drive sprockets (34) and (36) is sized to the diameter of the film roller (33) so that the film roller (33) will collect and release the same amount of film 26) as is being delivered to and requested from it by the drive sprockets (34) and (35) to avoid sagging or binding of the film (26). Film roller bearings (38) and (39) on trunnions (36) and (37) are fixed to the sides of the frame (20) by means of bearing support brackets (60) and 61) to permit film roller (33) to rotate on trunnions (36) and (37) within the hubs of the film roller bearings (38) and (39). Chains (28) and (29) also ride on idle sprockets (40) and (41), respectively, mounted on the back wail of the frame (20) with brackets (42) and (43). In one preferred embodiment, sprocket (43) is made active by connection to a motor (44) by shaft (45). Motor (44) is connected by cable (47) to a remote hand held switch (46) to drive sprocket (43) in a forward, fast forward, reverse or fast reverse. It will be appreciated that the motor (44) might be positioned elsewhere within the module and use another sprocket connected to either drive chain (28) or (29).

In another embodiment shown in Figure 4, the rear sprockets (40) and (41) have a second film roller mounted in a mirror arrangement to film roller (32) described above. Similarly, a second set of chains is added parallel to the first having sprockets and controls similarly constructed but slightly offset to permit independent movement without interference. This second film roller and associated drive mechanism would operate to bring film from an opposite direction to the first film roller to sandwich an image to focus attention to a specific area within the body of the transparency. The manual controls for film movement include thumb wheels (48) and (49) which (in the one film embodiment) are mounted on film roller trunnions (36) and (37). Although these elements are shown in the sequence of roller, sprocket then thumb wheel , it will be appreciated that the sequence could be roller, thumbwheel then sprocket. As shown in Figures 1 and 2, thumb wheels (48) and (49) extend above the cover (23) through slots (50) and (51). The thumb wheels permit the film roller (33) to be turned which will drive chains (28) and (29) to advance or retract the film (26). Other manual controls include handles (52) and (53) mounted on bolts (30) and (31) which extend through guide slots (54) and (55) in the cover (23) directly overhead of the chains (28) and (29). Sliding either handle (52) or (53) moves the chains and film roller (33) accordingly. The duality of the handles (52 and (53) and the thumb wheels (48) and (49) is to provide for left-handed or right-handed operators who are also then, free to operate from either side of the module. It will be appreciated that a complimentary construction will be provided in the two film embodiment.

Presenters experienced in the use of an overhead projector often work beside the overhead to preview a transparency prior to being placed on the overhead projector and will often glance at the overhead being projected to preview material, focus in on specific material or adjust the transparency and will therefore prefer the manual use of the handles (52) and (53) as well as the thumb wheels (48) and (49) over the automation of the hand control unit (46). Further, novice users of overhead projectors may feel more comfortable with the direct control offered by manually moving the film provided by the handles (52) and (53) and thumb wheels (48) and (49) over the automation offered by the hand control unit (46).

Both the two film manual and electric motor controls are capable of both displaying or concealing line by line and returning the film to a home or closed position in preparation for the next transparency. The hand control unit (46) will allow the operator to manipulate the module remotely as may be desired when numerous points are contained on one transparency without being tied to the display mechanism.

The highlight bar (56) is constructed of opaque or semi-opaque rigid plastic material. The highlight bar (56) is manually moveabie over the transparency (12) being guided in the guide slots channels (54) and (55) and always remains ahead of the film (26) because it is located in the same guide slots as the handles (52) and (53) but in advance thereof. In the two film embodiment it lies between the respective handles of the two films. A pointer (57) travels within the a guide (58) which traverses the highlight bar (56). It is slidable across and overhead of the transparency (12). A centre pin (59) mounting of the pointer (57) onto the highlight bar (56) permits 360 degrees of rotation.

Figure 5 is a front cross-sectional view of the highlight bar (56) positioned above a transparency (12) while riding in the guide slots (54) and (55) of the cover (23). Pointer (57) is shown on top of the highlight bar (56), however, it will be appreciated that the pointer (57) may be positioned below the highlight bar (56).

It is to be noted that the invention preferably utilizes an existing or conventional overhead projector to which parts are added without the necessity of otherwise modifying the projector. While the invention has been described in this manner it will be appreciated that the improvements described herein could be built integrally into an overhead projector without departing form the scope of the invention.

Claims

1. An overhead projector in which an image on a transparency is projected by a beam of light passing through the transparency directed by optical elements onto a viewing surface, having the improvement of: a masking apparatus comprising a transparent plate to support a transparency in a position for projection, at least one masking first film fastened to and wound on a roller axially supported for rotation under and near one longitudinal end of said transparent plate, a distal end of said first film being fastened to a fixed position on at least one continuous loop extending longitudinally under and positioned laterally of said transparent plate, said continuous loop engaging said roller in relational movement so that said first film may be drawn, or retracted from, under the transparent plate in response to movement of the continuous loop, control means to control the position of said continuous loop.

2. The overhead projector of claim 1 in which the masking device is a module comprising: a frame to provide a housing on said projector about said beam of light; a cover on said frame and having transparent plate to support a transparency in a position for projection by said light beam passing through said frame and said transparent plate.

3. The overhead projector of claim 2 in which the cover is hinged to the frame.

4. The overhead projector of claims 1 or 2 in which the control means comprises: at least one knob connected to said roller to rotate the roller.

5. The overhead projector of claims 1 or 2 in which the control means comprises: at least one handle connected to said continuous loop to control the position of the loop.

6. The overhead projector of claims 1 or 2 in which the control means comprises: at least one knob connected to said roller to rotate the roller and at least one handle connected to said continuous loop to control the position of the loop.

7. A module for an overhead projector in which an image on a transparency is projected by a beam of light passing through the transparency directed by optical elements onto a viewing surface, said module fitting on said projector and comprising: a housing having a transparent plate to support a transparency in a position that an image therein may be projected by said light beam passing through said housing, said transparent plate and said transparency; at least one masking first film fastened to and wound on a roller axially mounted for rotation within said housing near one end of said transparent plate, a distal end of said first film being fixed in relation to a point on at least one continuous loop mounted to rotate loopwise within said housing beside said transparent plate, said continuous loop engaging said roller to rotate axially in response to movement of the continuous loop to draw or withdraw first film from the roller to mask portions of the transparent plate from the beam of light; control means to engage and to control the position of said continuous loop.

8. The module of claim 7 in which the roller is mounted on trunnions and a sprocket is fixed to at least one trunnion and said continuous loop is a chain which engages said sprocket.

9. The module of claim 7 in which the roller is mounted on trunnions and a pulley is fixed to at least one trunnion and said continuous loop is a belt which engages said pulley.

10. The module of claims 7 and 9 in which the continuous loop is also mounted for loopwise rotation within said housing at an end of said transparent plate opposite said roller.

11. A module for an overhead projector in which an image on a transparency is projected by a beam of light passing through said transparency directed by optical elements onto a viewing surface, said module fitting on said projector and comprising: a housing having a transparent plate to support a transparency in a position that an image therein may be projected by said light beam passing through said housing, transparent plate and transparency; at least one masking first film fastened to and wound on a roller axially mounted on trunnions for rotation within said housing near one end of said transparent plate; a first sprocket fixed to a trunnion of said roller; a second sprocket mounted for rotation within said housing at an end of said transparent plate opposite said roller. a continuous chain loop mounted for loopwise rotation on and engaging said first and second sprockets and having a distal end of said first film from said roller attached in a fixed position on said loop, to draw or withdraw first film from the roller to mask portions of the transparent plate from the beam of light; control means to engage and to control the position of said continuous loop.

12. A module for an overhead projector in which an image on a transparency is projected by a beam of light passing through the transparency directed by optical elements onto a viewing surface, said module fitting on said projector and comprising: a housing having a transparent plate to support a transparency in a position that an image therein may be projected by said light beam passing through said housing, transparent plate and transparency; at least one masking first film fastened to and wound on a roller axially mounted on trunnions for rotation within said housing near one end of said transparent plate; a first pulley fixed to a trunnion of said roller; a second pulley mounted for rotation within said housing at an end of said transparent plate opposite said roller. a continuous belt loop mounted for loopwise rotation on and engaging said first and second pulleys and having a distal end of said first film from said roller attached in a fixed position on said loop, to draw or withdraw first film from the roller to mask portions of the transparent plate from the beam of light; control means to engage and to control the position of said continuous loop.

13. The module of claims 11 or 12 in which the control means comprises: at least one knob connected to said roller to rotate the roller.

14. The module of claims 11 or 12 in which the control means comprises: a thumb wheel attached to a trunnion of said roller and having a portion of said thumb wheel extending out of said housing through a slot for manual rotation.

15. The module of claims 11 or 12 in which the control means comprises: a pair of thumb wheels each attached to a trunnion on opposite sides of said roller and each having a portion extending out of said housing through a slot for manual rotation to control said roller.

16. The module of claims 11 or 12 in which the control means comprises: at least one handle connected to said continuous loop to control the position of the loop.

17. The module of claims 11 or 12 in which the control means comprises: two handles each being connected to a continuous loop and located in respective guide slots extending longitudinally on opposite sides of said transparent plate, said handles each having a portion extending outside said housing through a slot for manual control of the position of the loop.

18. The module of claims 11 or 12 in which the control means comprises: at least one knob connected to said roller to rotate the roller and at least one handle connected to said continuous loop to control the position of the loop.

19. The module of claims 11 or 12 in which the control means comprises one or more of: a pair of thumb wheels each attached to a trunnion on opposite sides of said roller and each having a portion extending out of said housing through a slot for manual rotation of said roller; and two handles each being connected to a continuous loop and located in respective guide slots extending longitudinally on opposite sides of said transparent plate, said handles each having a portion extending outside said housing through a slot for manual control of the position of the loop.

20. The module of claims 11 or 12 in which the control means comprises: a sprocket engaging said continuous loop; a shaft axially connected to sad sprocket; a variable speed and reversible drive motor engaging said shaft; and a remote switch to control the speed and direction of said motor.

21. The module of claims 11 or 12 in which the control means comprises one or more of: a pair of thumb wheels each attached to a trunnion on opposite sides of said roller and each having a portion extending out of said housing through a slot for manual rotation of said roller; two handles each being connected to a continuous loop and located in respective guide slots extending longitudinally on opposite sides of said transparent plate, said handles each having a portion extending outside said housing through a slot for manual control of the position of the loop; and a remote control system including a sprocket engaging said continuous loop, a shaft axially connected to said sprocket, a variable speed and reversible drive motor engaging said shaft; and a remote switch to control the speed and direction of said motor.

22. The module of claims 7, 11 or 12 having at least one highlight bar comprising a tinted transparent strip suspended transversely over said transparent plate and connected to a highlight handle positioned in a guide slot located to a side of and extending longitudinally of said transparent plate.

23. The module of claims 7, 11 or 12 having at least one highlight bar comprising a tinted transparent strip suspended transversely over said transparent plate and connected to a highlight handle positioned in a guide slot located to a side of and extending longitudinally of said transparent plate and having a pointer mounted to pivot and slide in a slot extending along the highlight bar.

24. The module of claims 7, 11 or 12 in which a duplicate apparatus is arranged in said housing to control a second film advancing and retracting from a second roller by means of at least one other continuous loop in an opposite direction to said first film to mask an opposing section of a transparency and said duplicate apparatus having an independent second control system.

25. A module for an overhead projector in which an image on a transparency is projected by a beam of light passing through the transparency directed by optical elements onto a viewing surface, said module fitting on said projector and comprising: a housing having a transparent plate to support a transparency in a position that an image therein may be projected by said light beam passing through said housing, said transparent plate and said transparency; at least one masking first film fastened to and wound on a roller axially mounted for rotation within said housing near one end of said transparent plate, a distal end of said first film being fixed in relation to a point on at least one continuous loop mounted to rotate loopwise within said housing beside said transparent plate, said continuous loop engaging said roller to rotate axially in response to movement of the continuous loop to draw or withdraw first film from the roller to mask portions of the transparent plate from the beam of light; control means to engage and to control the position of said continuous loop comprising one or more of: a pair of thumb wheels each attached to a trunnion on opposite sides of said roller and each having a portion extending out of said housing through a slot for manual rotation of said roller; two handles each being connected to a continuous loop and located in respective guide slots extending longitudinally on opposite sides of said transparent plate, said handles each having a portion extending outside said housing through a slot for manual control of the position of the loop; and a remote control system including a sprocket engaging said continuous loop, a shaft axially connected to sad sprocket, a variable speed and reversible drive motor engaging said shaft; and a remote switch to control the speed and direction of said motor; at least one highlight bar comprising a tinted transparent strip suspended transversely over said transparent plate and connected to a highlight handle positioned in a guide slot located to a side of and extending longitudinally of said transparent plate and having a pointer mounted to pivot and slide in a slot extending along the highlight bar.