GB2060193A

GB2060193A - Extension platform for holding transparencies on an overhead projector

Info

Publication number: GB2060193A
Application number: GB8026841A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-09-11
Filing date: 1980-08-18
Publication date: 1981-04-29
Also published as: DK379080A; CA1125066A; CH647340A5; GB2060193B; NL8005104A; FR2465247A1; SE8005825L; DE3025927A1; SE445394B; FR2465247B1

Abstract

An extension platform (13) for holding a book (11) of transparencies in an operative position on an overhead projector (10) includes a body member (19) adapted to receive and hold a book of transparencies, at least two suction cups (22) positioned on the underside of the body member for attaching and securing the body member to the stage area of an overhead projector, and fulcrum means (26) located under the body member which translates the downward gravitational force of the weight of the book of transparencies into an upward pull on the suction cups. In one embodiment, the extension platform is an integral part of a book of transparencies. <IMAGE>

Description

SPECIFICATION Extension platform for holding transparencies on an overhead projector The present invention generally relates to an extension platform. More particularly, it relates to an extension platform for supporting a pack of transparencies in an operative position on an overhead projector.

The novel extension platform of the present invention is particularly useful for supporting a pack of transparencies in an operative position on an overhead projector. The extension platform includes a body member adapted to receive and hold a pack of transparencies, at least two suction cups positioned on the underside of the body member for attaching and securing the body member to the stage area of an overhead projector and fulcrum means located beneath the body member to translate the downward gravitational force of the weight of the pack of transparencies into an upward pull on the suction cups.

There are two embodiments of the invention disclosed. In one embodiment there is a separate extension platform which is designed to be used to support any one of a number of packs of transparencies individually in an operative position on an overhead projector. In the other embodiment the extension platform is integrally attached to the cover of a book containing a pack of transparencies; thus, making the use of a separate extension platform unnecessary.

It is the primary object of the present invention to disclose a simple and convenient extension platform which is particularly useful for supporting a pack of transparencies in operative position on a projector.

Other objects and advantages will be apparent from the description and the drawings which follow: Figure 1 is a perspective view of an overhead projector with a book containing a pack of transparencies supported thereon in operative position by an extension platform of the present invention, Figure 2 is an enlarged perspective view of an embodiment of the invention which is a separate extension platform which can be used to support a pack of transparencies in the manner shown in Figure 1, Figure 3 is a side view, in section, showing the extension platform of Figure 2 on an overhead projector with a book containing a pack of transparencies in place and a transparency in position for projection, Figure 4 is a side view, in section, of the apparatus shown in Figure 3 with the main portion of the pack of transparencies raised and a transparency moved into storage position, Figure 5 is a side view similar to Figure 4 showing the extension platform and a pack of transparencies that is not in a book with protective covers, Figure 6 is a side view, in section, of an embodiment of the invention in which the extension platform is an integral part of the lower cover of a book containing a pack of transparencies, Figure 7 is a view of the apparatus of Figure 6 with the pack raised and a transparency moved into a storage position, Figure 8 is a perspective view of the embodiment of Figures 6 and 7 showing the lower cover of the book with the fulcrum assembled, Figure 9 is a perspective view like Figure 8 showing the fulcrum unassembled, Figure 10 is a perspective view of the book of transparencies shown in Figures 6 to 9 with the covers in position to protect the pack of transparencies.

Referring to Figure 1, an overhead projector 10 can be seen with a pack 11 of transparencies 12 positioned in operative position. The pack 11 of transparencies 1 2 is supported by an extension platform which cannot be seen in Figure 1. The extension platform which is identified by the numerals 13 and 13' in the other figures of the drawings may be a separate unit such as that seen in Figures 2 to 5 or an integral part of a book of transparencies such as seen in Figures 6 to 10.

Returning to Figure 1, it can be seen that the pack 11 of transparencies 12 has a coiled wire or ring binding 14. Such a binding is preferred because it permits an individual transparency 12 to be moved to a full lay-flat position on the stage 1 0a of the projector thus avoiding any distortion in the projected image. As seen in Figure 1, the pack 11 is contained in a book 1 5 having a pair of protective covers 1 6 and 1 7 joined by a hinge 1 8.

The preferrred embodiment of the separate extension platform 1 3 is shown in Figures 2 to 5.

As seen therein, the platform 1 3 comprises a body member 1 9 having a relatively small base 20 at one end and a relatively large upwardly inclined section 21 at the other end. Depending from the base 20 are three suction cups 22 which are used to secure the extension platform 1 3 to the stage 1 Oa of the overhead projector 10. The suction cups 22 are preferably of vinyl or silicone elastomer, and they have necks 22a which extend through openings 23 in the base 20. The suction cups 22 are retained in the openings 23 by a relatively rigid bar 24 which extends through aligned openings 25 in the necks 22a of the suction cups 22.

The top surface of the inclined section 21 is adapted to receive and hold a pack of 11 transparencies 12. Located on the underside of inclined section 21 of the body member 19 adjacent the point at which the inclined section 21 meets the base 20 is a generally wedge-shaped fulcrum 26.

The fulcrum 26, which may be molded of the same material as the main body member 19, supports the inclined section 21 at an angle of approximately 200 above the horizontai plane of the stage 1 Oa of the projector 10. The fulcrum 26 serves to translate the downward force exerted by the weight of the pack 11 on the inclined section 21 into a substantially upward pull on the suction cups 22. It has been discovered that the suction cups 22 hold most securely when the force which is exerted on them is a substantially vertical upward pull. Therefore, the preferred shape and position of the fulcrum 26 and the preferred angle at which the inclined section 21 is maintained by the fulcrum 26 should be selected so that the pull on the suction cups 22 is as vertically directed as possible.

Referring now to Figures 2, 3 and 4, it can be seen that the upper surface or top of the inclined section 21 of the extension platform 1 3 is provided with fingers 27 which rise above and extend substantially parallel to the top of the inclined section 21. The space 28 formed between the underside of the fingers 27 and the top of the inclined section 21 are adapted to receive and retain the outer edge of bottom cover 1 7 of the book of transparencies. The fingers 27 are preferably molded integrally with the body member 1 9 of the extension platform 13 and are of the same material.The fingers 27 prevent the lower or bottom cover 17 of the book 14 from being raised as might occur in the process of moving transparencies from the book 1 4 TO the stage 1 Oa and from the stage 1 Oa into the book 14.

In figures 2, 3 and 4, there also can be seen a pair of spaced apart upward projections 29 and 30 at the other end of the inclined section 21. As seen in Figures 3 and 4 the projections 29 and 30 cooperate with a projection receiving slot 31 in the hinge 18 of the book 14 to prevent the book 14 from sliding down the inclined surface and onto the stage 1 Oa. The upward projections 29 and 30 have openings 29a and 30a which are aligned with an opening 1 8a in the hinge 18. As seen best in Figure 2, a plug 32 is connected to the body member 19 by a strand of plastic material 33. The strand 33 prevents the plug 32 from becoming lost or misplaced.

When the book 14 is in place on the extension platform 13 with the outer edge of the lower cover 17 in the spaces 28 and the plug 32 in place in the aligned openings 29a, 30a and 1 8a of the projections 29 and 30 and the hinge 18, the book 14 cannot be accidentally dislodged from the extension platform 1 3 as could happen when the pack 11 is being raised and lowered in the process of moving the transparencies 1 2 onto the stage 1 Oa of the projector 10 and back into the pack 11 for storage.

In Figure 5, a pack 11 of transparencies 12 is shown which is not in a book having protective covers. The pack 11 of transparencies 12 shown therein has a single stiffening page 34 which is attached at one end to the pack 11 of transparencies 12 by a binding 1 4. The other end of the page 34 has a downwardly folded portion 35 with an opening 35a extending therethrough which can be aligned with the openings 29a and 30a in the projections 29 and 30. When the plug 32 is inserted therethrough the pack 11 of transparencies 12 is retained on the inclined section 20 of extension platform 13.

A second embodiment of the invention is shown in Figures 6 to 10; as seen therein the extension platform 13' is an integral part of a book 15' containing a pack 11' of transparencies 12'.

The book 15' has a top cover 16' and a bottom cover 17' connected by a hinge 18'. The pack 11' of transparencies 12' is connected to the free end of the bottom cover 17' by a ring binding 14' in the manner previously described.

In the second embodiment, the top cover 1 6' functions as in the first embodiment to support and protect the transparencies 12' during handling or storage, but the bottom cover 17', in addition, also serves as the body member 19' of the extension platform 13'. The bottom cover 17' as seen in Figures 6 and 7 flexes to form a generally horizontal base 20' and an inclined section 21'.

Referring now to Figures 8 and 9, it can be seen that depending from the base 20' of the free end of the cover 1 7' are a pair of suction cups 22' for securing the book 14' and the pack 11' of transparencies 12' to the stage 1 Oa' of the overhead projector 10'. The suction cups 22' can be affixed to the cover 17' in a manner similar to that previously described in connection with the first embodiment.

Turning now to Figures 6 and 7, it can be seen that the book 1 5' is supported in the preferred inclined position by a fulcrum 26t. The fulcrum 26' translates the gravitational force exerted by the weight of the book 15' into an upward pull on the suction cups 22'.

Returning to Figure 8, it is seen that the fulcrum 26' is formed of interlocked flaps 36 and 37. The flaps 36 and 37 when not interlocked lay flat as seen in Figure 9 so that the covers 1 6' and 17' can be moved into position as seen in Figure 10 to protect the pack 11' of transparencies for storage.

For purposes of aligning the book 1 5' properly on the stage 1 Oa' as shown in Figures 6 and 7 so that the transparency 12' to be projected will be properly aligned on stage 1 0a', the cover 17' may be provided with alignment markings (not shown).

In the second embodiment described, the extension platform 13' is an integral part of the book 15'; therefore, there is no need for means to prevent the book from sliding onto the stage 1 Oa' of the overhead projector or to retain the lower cover 17'.

As can be seen in Figures 3,4, 5, 6 and 7, when either embodiment of the extension platform of the present invention is properly oriented on the projector and a pack of transparencies is in place, the continuous binding which is attached to the upper cover 1 6, 16' or the page 34 will extend past the edge of the extension platform. This permits the transparencies to be moved into a projecting position in which they lay flat upon the stage of the projector. Thus, any possibility of distortion which might occur due to the failure of the transparency to lay flat upon the stage is avoided.

Both of the embodiments of the invention are preferably used in substantially the same manner.

Therefore, the use of the extension platform will be described in detail only in connection with the embodiment of Figures 2 to 4.

The extension platform 1 3 is first secured to the stage 1 Oa of the overhead projector 10 by pressing the suction cups 22 securely in place on a flat uninterrupted surface of the stage 1 Oa. The position of the suction cups 22 on the stage 1 Oa are selected, preferably with the help of alignment markings, so that when a transparency 12 is moved onto the stage it will be properly aligned for projection and the fulcrum 26 will also rest upon the stage 1 Oa. To improve the stability of the extension platform 1 3 on the overhead projector 10, the bottom of the fulcrum 26 may be provided with a pad 38 of a suitable slip resistant material as seen in Figures 3, 4 and 5.

When the extension platform 1 3 is secured as described to the stage 1 Oa of the projector 10 and a pack 11 of transparencies 12 is in place, a transparency 12 may be moved into a projecting position upon the stage 1 0a as seen in Figure 1.

When it is desired to replace that transparency 12 with another, the pack 11 of the transparencies 12 is raised as shown in Figures 4 or 5 and the transparency 1 2 which was projected is rotated into storage. When the pack 11 is lowered, a new transparency 12 can be rotated into a projecting position on the stage 1 Oa. The described acts can be performed quickly without removing the pack 11 from the extension platform 1 3 or the extension platform 1 3 from the overhead projector 10 by even an operator with only limited experience. In addition, all of these acts can be accomplished without using the auxiliary stages that were previously considered necessary.

It will be readily apparent to those skilled in the art that the extension platform of the present invention provides significant advantages over those which are previously available. It also will be apparent that a number of modifications and changes can be made without departing from the spirit and scope of the present invention.

Therefore, it is to be understood that the invention is not to be limited except by the ciaims which follow.

Claims

1. An extension platform for holding a pack of transparencies in an operative position on an overhead projector comprises: a. a body member for supporting a pack of transparencies, b. at least two suction cups on the underside of the body member at one end thereof for attaching it to the stage area of an overhead projector, and c. fulcrum means located beneath the body member intermediate the ends thereof, said fulcrum being positioned to translate the downward gravitational force of the weight of the pack of transparencies into a substantially vertical upward pull on the suction cups.

2. An extension platform of claim 1 which includes means for securing the pack of transparencies to the body member.

3. An extension platform of claim 2 in which the means for securing the pack of transparencies to the body member is an upward projection at the other end of the body member which projection cooperates with the pack to prevent it from being separated from the extension platform.

4. An extension platform of claim 3 in which the pack is in a book and the upward projection and the hinge of the book have aligned openings into which a plug can be inserted to lock the book to the body member.

5. The extension platform of claim 4 which includes fingers located on the topside of the body adjacent the one end thereof which prevent the lower cover of the book from being raised off the body member.

6. An extension platform of claim 1 in which the fulcrum means is a generally wedge-shaped member attached to the underside of the body member.

7. An extension platform of claim 1 in which the fulcrum means is comprised of normally layflat members that are interlocked to form a generally wedge-shaped fulcrum.

8. An extension platform of claim 7 in which the fulcrum means is attached to the cover of a book of transparencies.

9. An extension platform of claim 8 in which the book of transparencies has a pair of covers which can be closed when the fulcrum is unassembled to protect the fulcrum means and the transparencies.

10. An extension platform for holding a pack of transparencies in an operative position on an overhead projector comprises: a. a body member having a base and an inclined section for supporting the pack of transparencies, b. at least two suction cups on the underside of the base for attaching the body member to the stage area of an overhead projector, and c. fulcrum means located beneath the body member intermediate the ends thereof, said fulcrum being positioned to translate the downward gravitational force of the weight of the pack of transparencies into a substantially vertical upward pull on the suction cups.

11. An extension platform for holding a pack of transparencies on an overhead projector substantially as described with reference to Figures 2 to 5 or Figures 6 to 10 of the accompanying drawings.