GB1593591A – Film cassettes
– Google Patents
GB1593591A – Film cassettes
– Google Patents
Film cassettes
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Publication number
GB1593591A
GB1593591A
GB3032877A
GB3032877A
GB1593591A
GB 1593591 A
GB1593591 A
GB 1593591A
GB 3032877 A
GB3032877 A
GB 3032877A
GB 3032877 A
GB3032877 A
GB 3032877A
GB 1593591 A
GB1593591 A
GB 1593591A
Authority
GB
United Kingdom
Prior art keywords
film
cassette
film strip
viewing window
strip
Prior art date
1978-01-19
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3032877A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Qualidux Industrial Co Ltd
Original Assignee
Qualidux Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1978-01-19
Filing date
1978-01-19
Publication date
1981-07-22
1978-01-19
Application filed by Qualidux Industrial Co Ltd
filed
Critical
Qualidux Industrial Co Ltd
1978-01-19
Priority to GB3032877A
priority
Critical
patent/GB1593591A/en
1981-07-22
Publication of GB1593591A
publication
Critical
patent/GB1593591A/en
Status
Expired
legal-status
Critical
Current
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Classifications
G—PHYSICS
G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
G03B21/00—Projectors or projection-type viewers; Accessories therefor
Description
(74) IMPROVEMENTS IN AND RELATING TO
FILM CASSETTES
(71) We, QUALIDUX INDUSTRIAL
COMPANY LIMITED, a Hong Kong Company, of Tin Fung Industrial Mansion, 63
Wong Chuk Hang Road, 13th Floor, Aberdeen, Hong Kong, and ERNST KONRAD
ELSNER, a citizen of the Federal Republic of
Germany, of Royal Hotel, Bangkok, Thailand, do hereby declare the invention, for which we pray that a patent may be granted to use, and the method by which it is to be performed to be particularly described in and by the following statement:
This invention relates to film cassettes which contain an endless length of film strip.
In such cassettes, the endless length of film strip can carry «motion» pictures and the film strip is in the form of a coil. This coil is mounted in the cassette at an angle to the end walls of the cassette. One loop of the coil is fed from one side of the coil, for example the inside, spirally up over the top of the film coil, past a viewing or projection window through which light is passed to illuminate the film and is then wound on the other side, for example the outside, of the film coil.
Such cassettes may be used in a hand-held projector or viewer in which the film is fed forward frame by frame by a pin or needle which is inserted through a drive slot in the cassette to engage the perforations in the film strip, the pin or needle being moved transversely to move the film past the projection window.
According to the present invention there is provided a film cassette comprising a housing containing an endless length of film strip arranged in a coil with one loop of the coil extending within the housing past a viewing window through the housing and a driving station where, in use, a pin of the drive of a viewer or projector can extend through an opening in the housing into engagement with perforations in the film strip to advance the film strip one frame at a time past the viewing window, the said one loop extending from the outside of the coil to the inside of the coil in a curved path, the curvature of which, other than at the viewing window, is nowhere along it substantially different from the curvature of the other loops in the coil except that in the path of the said one loop of film strip upstream of the viewing window, there may be one or more members around or between which the film strip passes with a curvature opposite to that of its normal curvature to provide a braking effect to movement of the said one loop of the film strip, and the viewing window being positioned on a portion of a side wall of the housing which has a substantially flat inwardly-directed surface and stationary holding members being positioned one on either side of the viewing window so that, as the film strip is advanced past the viewing window, those holding members hold a portion of the said one loop of the film strip flattened against the flat surface.
According to one embodiment of the invention, the film cassette comprises end walls joined by a substantially cylindrical side wall, the side wall having through it a drive slot through which, in use, the said pin can project into engagement with perforations in the said one loop of the film strip to advance the strip frame by frame past the viewing window.
One problem which arises when moving the film strip in film cassettes is that of properly and accurately aligning each frame opposite the viewing window. The film should be held taut so as not accidentally to move out from alignment with the window and hitherto tension has been applied to the film through a pressure plate having a window which is aligned with the projection window. The film strip is then fed between the pressure plate and the housing and the pressure plate is urged frictionally into contact with the film by a spring. Also, a friction brake is often employed which bears on the film. These previous proposals have been effective but are comparatively expensive to manufacture and assemble.
In a cassette according to the invention, stationary holding members are positioned one on either side of the viewing window so that, as the film strip is advanced past the viewing window, those holding members hold a portion of the said one loop of the film
strip flattened against the flat surface.
As the film strip has a normal set radius of curvature due to its being wound into a coil and due to the material from which it is made, the film strip resists being straightened and when straightened has a tendency to return into its longitudinally curved state.
This tendency causes the film frictionally to bear against the holding members, e.g. pins, thus causing the necessary resistance to free movement of the portion of the film opposite the projection window. Hence, the necessary tautness if achieved without the necessity of having to provide resilient brake members or a pressure plate. The use of these holding members also enables the cassette to be kept compact in size.
If desired, an additional brake effect may be provided in the cassette upstream of the window by providing pins or curved surfaces around or between which the film is caused to pass with a curvature opposite to that of its normal set curvature, thus again creating a friction resistance between the film and the pins.
Another problem in the accurate alignment of the film strip with the projection or viewing window arises when the needle or pin of a viewer or projector which is used to advance the film strip, is inserted into a new perforation in the edge of the strip. Unless the pin or needle is very accurately aligned with the centre of the perforation in the strip, it may move the strip across its width so that the film strip is no longer accurately positioned opposite the projection window.
This problem can be solved by making the movement of the pin or needle very accurate but this puts up the cos of the projector or viewer.
A cassette in accordance with one preferred embodiment of this invention, therefore, has a side wall in which is formed a drive slot adjacent the path of the said one loop of the coil, the slot being designed to receive a pin of the drive of a viewer or projector so that the pin can engage in the pertorations in the edge of the film strip, the pin being movable along the length of the slot to advance the film along its path within the cassette over the length of a frame of the film strip, the said slot tapering in a direction transverse to the movement of the film strip from a relatively wider opening at the outside of the cassette to a relatively smaller opening at the inside of the cassette, the smaller opening being substantially of the same width as that of the perforations in the film strip.
In this way, if the pin or needle is slightly out of alignment as it approaches the cassette, it strikes either side of the tapering slot and is guided by the taper to a position in which it is accurately aligned with the centre of the perforation in the film strip.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a plan view of one embodiment of film cassette in accordance with the invention with the lid removed;
Figure 2 is a side elevation of the cassette shown in Figure 1;
Figure 3 is a scrap elevation on the line
III-III of Figure 1;
Figure 4 is a scrap section on the line IV-IV of Figure 1;
Figure 5 is an enlarged view of the portion of the cassette surrounding the viewing window; and
Figure 6 is an exploded view of a cassette as shown in Figure 1 and a viewer therefor.
The film cassette generally shown in Figures 1 and 2 has a circular body 2 and contains an endless length of film strip 4. The film strip is stored as a coil 6 resting on an inclined support surface 8 extending up from the base at an angle to the horizontal.
One loop of the film extends parallel to circular end walls of the cassette and out of line with the other loops of the coil in a path indicated by arrows A from the outer periphery of the coil against the side wall of the cassette within suitable guide surfaces forming part of the cassette body, and past a drive slot 1û through which a drive needle or pin 12 of the viewer shown in Figure 6, reciprocates to move to advance the film strip one frame at a time. The film then moves in the direction indicated by arrows A past a projection or viewing window 26 aligned with a cut-away angled channel 16 in one end wall of the cassette body (see Figure 6). Light can pass through this channel to enable a viewer to see the image contained on one frame of the film strip, through an eye-piece 18 having a suitable lens, the eye-piece forming part of the viewer shown in Figure 6 in which the cassette may be inserted when the film is to be viewed.
The film, after passing the window 26, is fed smoothly, i.e. without any substantial changes in its curvature over that of the film strip in the coil 6, over the top of the coil 6 between curved guides 20 (see Figure 1) so that it has a radius of curvature substantially equal to that of the interior loop of the coil 6 and is then fed back to the inside of the coil.
It will thus be seen that the film is maintained with a smooth curvature and in a circular and/or arcuate path throughout its movement from one side of the coil past the viewing window to the other side of the coil.
A portion 24 of the cassette side wall on each side of the projection or viewing window 26 is flattened and two pins 28 project downwardly one on each side of the window opposite to but slightly spaced from, the flattened portion 24 so that the film strip 4 is flattened as it passes the window and is held in the flattened condition by the pins 28 against the natural set curvature of the film strip. As the strip tends to resume its natural curvature friction is created between the film and the pins 28 which friction acts to stop any free movement of the film and to hold it taut opposite to the projection window.
Two further pins 30 are provided upstream of the projection window in the path of the film strip and a smaller pin or rounded projection 32 extends outwardly from the sidewall of the cassette so that film 4 is fed in a tortuous path between the pins 30 and 32 as can be seen clearly in Figures 1 and 5. The curvature which the film has to adopt when it passes between the pins is opposite to that of the film’s natural curvature so that friction is created between the pins and the film, causing a brake on free movement of the film and assisting in holding the film with one frame aligned with the window 26.
It will be appreciated that the pins 28, 30 and 32 provide an effective brake and tensioning device for the film strip merely by using the natural tendency of the film to resume a set curvature without the necessity of having any moving parts or springs.
As best seen in Figure 4, the drive slot 10 through which the needle or pin 12 is caused to reciprocate during advance of the film strip is provided with upper and lower tapering surfaces 34 and 35. This has the effect of ensuring that the needle or pin 12 is always accurately aligned with the perforations 38 in the edge of the film strip, these perforations being of substantially identical width to that of the slot 10 at the inside of the wall of the cassette. In this way the film strip is prevented from being moved up or down relative to the body of the cassette which could occur if the needle was not aligned with the opening but rather tended to press up or down on the upper or lower surfaces of the perforations in the film.
Once the needle has been engaged in a perforation in the film strip, it is moved by the viewer along the length of the slot 10 so as to feed the film strip forward so causing the next frame to be positioned opposite to the viewing window of the cassette. The pin is then moved outwardly again and back to a position opposite a further perforation in the tllm strip and then again reciprocated through the slot 10 for a further forward movement of the strip.
The film strip is held in position opposite the slot 10 by means of pins 40 and 42 seen in
Figure 4.
When the cassette is to be used with the viewer shown in Figure 6, it is snapped into the opening 44 in a position with the viewing window 26 aligned with the eye-piece 18 of the viewer. The lens in the eye-piece may be adjusted for focussing by rotation of a knurled wheel 46.
The pin or needle 12 engages in the slot 10 of the cassette and is driven by a conventional battery powered motor 48 on manual operation of a switch 50. The batteries for the motor 48 are housed in a compartment in the handle of the viewer having a removable cover 52.
Light passes through the channel 16 and through the frame of the film strip aligned with the window 26 to be seen by a user through the lens 18.
Our copending Patent Application No.
8030103 (Serial No. 1593592) describes and claims a film cassette comprising a housing having opposed side walls and a peripheral wall joining the edges of the side walls, the housing containing an endless length of film strip arranged in a coil with one loop of the coil extending within the housing past a viewing window through the peripheral wall and a driving station which is spaced along the said wall and is separate from the viewing window, the driving station comprising a slot through the peripheral wall through which, in use, a drive pin of a viewer or projector can extend into engagement with perforations in the film strip to advance the film strip one frame at a time past the viewing window, the said one loop extending from the outside of the coil to the inside of the coil in a smoothly curved path and without substantial twisting about the longitudinal axis of the film so that the orientation of the face of the film about its longitudinal axis is substantially the same in the said one loop as in the remainder of the coil, and a cut-away portion in one side wall of the housing to allow the passage of light through the frame of the film aligned with the viewing window and through the viewing window.
WHAT WE CLAIM IS:
1. A film cassette comprising a housing containing an endless length of film strip arranged in a coil with one loop of the coil extending within the housing past a viewing window through the housing and a driving station where, in use, a pin of the drive of a viewer or projector can extend through an opening in the housing into engagement with perforations in the film strip to advance the film strip one frame at a time past the viewing window, the said one loop extending from the outside of the coil to the inside of the coil in a curved path, the curvature of which, other than at the viewing window, is nowhere along it substantially different from the curvature of the other loops in the coil except that in the path of the said one loop of film strip upstream of the viewing window, there may be one or more members around or between which the film strip passes with a curvature opposite to that of its normal curvature to provide a braking effect to movement of the said one loop of the film strip, and the viewing window being positioned on a portion of a side wall of the housing which has a substantially flat inwardly-directed sur
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (8)
**WARNING** start of CLMS field may overlap end of DESC **.
strip. As the strip tends to resume its natural curvature friction is created between the film and the pins 28 which friction acts to stop any free movement of the film and to hold it taut opposite to the projection window.
Two further pins 30 are provided upstream of the projection window in the path of the film strip and a smaller pin or rounded projection 32 extends outwardly from the sidewall of the cassette so that film 4 is fed in a tortuous path between the pins 30 and 32 as can be seen clearly in Figures 1 and 5. The curvature which the film has to adopt when it passes between the pins is opposite to that of the film’s natural curvature so that friction is created between the pins and the film, causing a brake on free movement of the film and assisting in holding the film with one frame aligned with the window 26.
It will be appreciated that the pins 28, 30 and 32 provide an effective brake and tensioning device for the film strip merely by using the natural tendency of the film to resume a set curvature without the necessity of having any moving parts or springs.
As best seen in Figure 4, the drive slot 10 through which the needle or pin 12 is caused to reciprocate during advance of the film strip is provided with upper and lower tapering surfaces 34 and 35. This has the effect of ensuring that the needle or pin 12 is always accurately aligned with the perforations 38 in the edge of the film strip, these perforations being of substantially identical width to that of the slot 10 at the inside of the wall of the cassette. In this way the film strip is prevented from being moved up or down relative to the body of the cassette which could occur if the needle was not aligned with the opening but rather tended to press up or down on the upper or lower surfaces of the perforations in the film.
Once the needle has been engaged in a perforation in the film strip, it is moved by the viewer along the length of the slot 10 so as to feed the film strip forward so causing the next frame to be positioned opposite to the viewing window of the cassette. The pin is then moved outwardly again and back to a position opposite a further perforation in the tllm strip and then again reciprocated through the slot 10 for a further forward movement of the strip.
The film strip is held in position opposite the slot 10 by means of pins 40 and 42 seen in
Figure 4.
When the cassette is to be used with the viewer shown in Figure 6, it is snapped into the opening 44 in a position with the viewing window 26 aligned with the eye-piece 18 of the viewer. The lens in the eye-piece may be adjusted for focussing by rotation of a knurled wheel 46.
The pin or needle 12 engages in the slot 10 of the cassette and is driven by a conventional battery powered motor 48 on manual operation of a switch 50. The batteries for the motor 48 are housed in a compartment in the handle of the viewer having a removable cover 52.
Light passes through the channel 16 and through the frame of the film strip aligned with the window 26 to be seen by a user through the lens 18.
Our copending Patent Application No.
8030103 (Serial No. 1593592) describes and claims a film cassette comprising a housing having opposed side walls and a peripheral wall joining the edges of the side walls, the housing containing an endless length of film strip arranged in a coil with one loop of the coil extending within the housing past a viewing window through the peripheral wall and a driving station which is spaced along the said wall and is separate from the viewing window, the driving station comprising a slot through the peripheral wall through which, in use, a drive pin of a viewer or projector can extend into engagement with perforations in the film strip to advance the film strip one frame at a time past the viewing window, the said one loop extending from the outside of the coil to the inside of the coil in a smoothly curved path and without substantial twisting about the longitudinal axis of the film so that the orientation of the face of the film about its longitudinal axis is substantially the same in the said one loop as in the remainder of the coil, and a cut-away portion in one side wall of the housing to allow the passage of light through the frame of the film aligned with the viewing window and through the viewing window.
WHAT WE CLAIM IS:
1. A film cassette comprising a housing containing an endless length of film strip arranged in a coil with one loop of the coil extending within the housing past a viewing window through the housing and a driving station where, in use, a pin of the drive of a viewer or projector can extend through an opening in the housing into engagement with perforations in the film strip to advance the film strip one frame at a time past the viewing window, the said one loop extending from the outside of the coil to the inside of the coil in a curved path, the curvature of which, other than at the viewing window, is nowhere along it substantially different from the curvature of the other loops in the coil except that in the path of the said one loop of film strip upstream of the viewing window, there may be one or more members around or between which the film strip passes with a curvature opposite to that of its normal curvature to provide a braking effect to movement of the said one loop of the film strip, and the viewing window being positioned on a portion of a side wall of the housing which has a substantially flat inwardly-directed sur
face and stationary holding members being positioned one on either side of the viewing window, so that, as the film strip is advanced past the viewing window, those holding members hold a portion of the said one loop of the film strip flattened against the flat surface.
2. A film cassette as claimed in Claim 1 in which the housing comprises end walls joined by a substantially cylindrical side wall, the side wall having through it a drive slot through which, in use, the said pin can project into engagement with perforations in the said one loop of the film strip to advance the strip frame by frame past the viewing window.
3. A film cassette as claimed in Claim 2 comprising mounting means to mount the loops of the coil other than the said one loop inclined at an angle to the end walls, and guide means for the said one loop guiding that loop past the viewing window and drive slot in a path substantially parallel to the end walls.
4. A film cassette as claimed in Claim 3 in which the mounting means includes a wedge-shaped recess extending across one of the end walls, the high end of the recess terminating substantially flush with that end wall and the low end being aligned with the viewing window in the side wall.
5. A cassette as claimed in any preceding claim in which the holding members are each in the form of pins.
6. A film cassette as claimed in any preceding claim which has a side wall in which is formed a drive slot adjacent the path of the said one loop of the coil, the slot being designed to receive a pin of the drive of a viewer or projector so that the pin can engage in the perforations in the edge of the film strip, the pin being movable along the length of the slot to advance the film along its path within the cassette over the length of a trame of the film strip, the said slot tapering in a direction transverse to the movement of the film strip from a relatively wider opening at the outside of the cassette to a relatively smaller opening at the inside of the cassette, the smaller opening being substantially of the same width as that of the perforations in the film strip.
7. A film cassette according to Claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.
8. The combination of a film cassette and a viewer therefor substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.
GB3032877A
1978-01-19
1978-01-19
Film cassettes
Expired
GB1593591A
(en)
Priority Applications (1)
Application Number
Priority Date
Filing Date
Title
GB3032877A
GB1593591A
(en)
1978-01-19
1978-01-19
Film cassettes
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
GB3032877A
GB1593591A
(en)
1978-01-19
1978-01-19
Film cassettes
Publications (1)
Publication Number
Publication Date
GB1593591A
true
GB1593591A
(en)
1981-07-22
Family
ID=10305902
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB3032877A
Expired
GB1593591A
(en)
1978-01-19
1978-01-19
Film cassettes
Country Status (1)
Country
Link
GB
(1)
GB1593591A
(en)
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US5691801A
(en)
*
1996-04-26
1997-11-25
Morton; Jay
Hand-held viewer for motion picture cassettes
1978
1978-01-19
GB
GB3032877A
patent/GB1593591A/en
not_active
Expired
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US5691801A
(en)
*
1996-04-26
1997-11-25
Morton; Jay
Hand-held viewer for motion picture cassettes
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Legal Events
Date
Code
Title
Description
1981-10-07
PS
Patent sealed
1986-08-28
PCNP
Patent ceased through non-payment of renewal fee
