FAULTY INSERTION PREVENTIVE DEVICE FOR CARTRIDGES
United States Patent 3650378
A faulty insertion preventive device for a cartridge insertable into a chamber having an opening of the same size as the cartridge. A key projects into the opening and a slot is formed on the top of the cartridge by spaced rows. For proper positioning the cartridge must be inserted so that the key fits within the slot for abutment against transverse stop adjacent the end of the rows.
US Patent References:
Sound projector provided with vision screen and working by means of interchangeable loading apparatus
Bavaro - January 1966 - 3227508
Film cassette
Nerwin - March 1965 - 3175222
Clutch apparatus
Brewster et al. - October 1966 - 3280947
Sound projector provided with vision screen and working by means of interchangeable loading apparatus
Bavaro - January 1966 - 3227508
Film cassette
Nerwin - March 1965 - 3175222
Clutch apparatus
Brewster et al. - October 1966 - 3280947
Inventors:
Kakiuchi, Tokusaburo (Tokyo, JA)
Akiyama, Hideaki (Tokyo, JA)
Akiyama, Hideaki (Tokyo, JA)
Application Number:
04/839873
Publication Date:
03/21/1972
Filing Date:
07/08/1969
View Patent Images:
Export Citation:
Assignee:
Kabushiki Kaisha Ricoh (Tokyo, JA)
Primary Class:
Other Classes:
360/132, 360/60, 360/137, 353/18, 33/563
International Classes:
G03B21/32; B65D85/00; G11B23/12; G11B1/00
Field of Search:
206/52,1 312/330 220/41 287/58CT 179/1.2Z 242/71.2,195 353/18
Primary Examiner:
Dixson Jr., William T.
Claims:
What is claimed is
1. In combination with a receiving chamber having a rectangularly shaped opening with the longer sides extending vertically and the shorter sides extending horizontally, and a cartridge having outer enclosing surfaces providing substantially the same rectangular cross-sectional shape as said opening and adapted to be inserted therein to operative position, a faulty insertion preventive device comprising
2. The combination according to claim 1 in which said transverse protrusion extends to said remote end of said cartridge.
3. The combination according to claim 1 in which each row comprises a series of separate spaced protrusions.
4. The combination according to claim 3 in which each spaced protrusion of one row is located opposite a spacing between protrusions in said other row.
5. The combination according to claim 3 in which each row protrusion has an outer longitudinal surface, and said longitudinal surface is located to be out of coplanar alignment with the adjacent longitudinal surface of said cartridge.
1. In combination with a receiving chamber having a rectangularly shaped opening with the longer sides extending vertically and the shorter sides extending horizontally, and a cartridge having outer enclosing surfaces providing substantially the same rectangular cross-sectional shape as said opening and adapted to be inserted therein to operative position, a faulty insertion preventive device comprising
2. The combination according to claim 1 in which said transverse protrusion extends to said remote end of said cartridge.
3. The combination according to claim 1 in which each row comprises a series of separate spaced protrusions.
4. The combination according to claim 3 in which each spaced protrusion of one row is located opposite a spacing between protrusions in said other row.
5. The combination according to claim 3 in which each row protrusion has an outer longitudinal surface, and said longitudinal surface is located to be out of coplanar alignment with the adjacent longitudinal surface of said cartridge.
Description:
BACKGROUND OF THE INVENTION
The present invention relates to a faulty insertion preventive device for cartridges and more particularly for cartridges containing therein film or the like.
In a machine such as a cartridge type cineprojector utilizing a cartridge the cartridge must be inserted into the machine in a predetermined direction. Therefore, when the cartridge is inserted in the erroneous or wrong direction, the machine will be damaged or become out of order. Thus, there have been proposed various faulty insertion preventive method and means. But the conventional methods and means are such that an operator must judge the direction of insertion by checking the configurations of the cartridge or he may try to start the insertion of the cartridge into a chamber and then see whether the cartridge has been correctly inserted or not.
SUMMARY OF THE INVENTION
In brief, the present invention provides a faulty insertion preventive device for cartridges characterized in that a projection is formed adjacent to the opening of a cartridge insertion chamber of a machine so as to extend beyond an imaginary opening defined by the upper, lower and side surfaces of said chamber; a longitudinal recess is formed in a cartridge for engagement with said projection when inserted; and stop means is disposed at the trailing or rear end of said recess in abutment or substantially abutment relation with said projection when inserted.
According to one embodiment of the present invention, the projection within the chamber consists of one protrusion; the recess of the cartridge consists of slots formed in the upper surface and/or one side surface of the cartridge; and said stop means is a projection extending across said slots at the trailing ends thereof. When the cartridge is inserted its full extent, the stop projections abut or substantially abut against the projection of the cartridge chamber. If the cartridge is to be inserted into the chamber in the reverse or wrong direction, the projection of the chamber abuts against the stop projection of the cartridge or the surface of the cartridge so that the cartridge is not permitted to be inserted. Thus, a faulty insertion may be securely prevented.
According to another embodiment of the present invention, said slot is defined by a plurality of spaced apart projections arranged in two rows. This arrangement will facilitate the fabrication of the cartridges.
According to a further embodiment of the present invention, said recess of the cartridge is a bevel formed along one longitudinal side of the cartridge while said projection in said cartridge chamber is also a bevel corresponding to the first mentioned bevel of the cartridge and extending from the opening or a portion adjacent thereto of the cartridge chamber. This arrangement is most advantageous in simplifying the fabrication steps as the configurations are very simple.
One of the objects of the present invention is to prevent completely the faulty insertion of the cartridge.
Another object of the present invention is to provide a faulty insertion preventive device for cartridges which gives a warning of a faulty insertion or mis-insertion to an operator at the instant when he tries to insert the cartridge.
A further object of the present invention is to provide a faulty insertion preventive device for cartridges in which the cartridge and its insertion chamber have simple configurations and constructions.
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the illustrative embodiments thereof with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first embodiment of the present invention;
FIGS. 2A, 2B and 2C are perspective views illustrating various modifications of the end or stop face of a slot formed in one surface of the cartridge;
FIG. 3 is a perspective view of another embodiment of the present invention;
FIG. 4 is a perspective view illustrating a modified construction of the end or stop of the slot of the cartridge;
FIG. 5 is a perspective view illustrating a modification of the projections of FIG. 4; and
FIG. 6 is a perspective view of a third embodiment of the present invention .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a cartridge generally indicated by 1 is inserted into an insertion chamber or recess 2 of a cartridge type cineprojector, and has a front end surface 1a, a rear end surface 1b, an upper surface 1c, a bottom surface 1d, and side surfaces 1e. The cartridge 1 is generally a box rectangular in both of the longitudinal and transverse cross sections. The cross-sectional area and configuration of at least the opening or the portion adjacent thereto of the chamber correspond to those of the cartridge so as to securely hold it in position when inserted. A key 2a is disposed at the inner upper surface adjacent to the opening of the insertion chamber 2 while a key slot 1f is formed in the upper surface 1c of the cartridge 1 and the key 2a is fitted in this slot 1f for guiding the cartridge when inserted. The length of the slot 1f is such that when the cartridge 1 is inserted into the insertion chamber 2 so as to be set to an operative position, the key 2a abuts against the end wall 1ga of the slot 1f or is located at a position adjacent thereto. In the embodiment shown in FIG. 1, the end surface 1ga is formed by a transverse wall 1g and a short slot 1h having the same width and depth as that of the slot 1f is formed from the transverse wall 1g to the rear end face 1b.
When the cartridge 1 with the construction described above is attempted to be inserted into the insertion chamber 2 with the bottom surface 1d facing upwardly, the cartridge 1 insertion into the chamber 2 is not possible because the bottom surface 1d has no slot into which is fitted the key 2a. When the cartridge 1 is inserted from its rear end surface 1b into the chamber 2 with the bottom surface 1d directed upwardly, the cartridge is not permited to be inserted for the previously presented reason. When the cartridge 1 is inserted from its rear end surface 1b with the upper surface 1c directed upwardly, the key 2a fits into the short slot 1h formed in the upper surface 1c but it will soon abut against the transverse wall 1g so that the cartridge will not be permitted to advance further. Therefore, it will be seen that the cartridge 1 may be only inserted into the insertion chamber 2 correctly when the cartridge 1 is inserted from the front end surface 1a with the upper surface 1c facing upwardly and consequently the slot 1f directed upwardly so that an operator may correctly insert the cartridge 1 without any particular precaution.
It will be understood that the slot 1f may be formed in the bottom surface 1d, or side surfaces 1e instead of the upper surface 1c while the key 2a of the insertion chamber 2 may be disposed so as to accordingly oppose the slot 1f. Furthermore, the slot 1f may be formed in the upper surface 1c and one of the side surfaces 1e or in the bottom surface 1d and one of the side surfaces 1e while two keys 2a may be provided for engagement with these slots. In FIG. 1, the key 2a is shown as a screw having a head, but any other suitable key means may be formed integrally or independently of the insertion chamber 2. As shown in FIG. 2A, the end face 1ga of the slot 1f serving as a stop for the key 2a may be replaced with a wall 1i spaced apart from the inner surfaces of the slot 1f so as to provide an end face lia. Alternately, the end face 1ga may be replaced with an end face 1ja of a wall 1j extending from the end of the slot 1f to the rear end surface 1b. As shown in FIG. 2C, a circular projection 1k may be formed in the slot 1f for providing the end face 1ka as a stop. Thus, it will be seen that any suitable means may be provided as stop for the key 2a.
Referring to FIG. 3, a cartridge 31 of the present invention has a front end surface 31a, a rear end surface 31b, an upper surface 31c, a bottom surface 31d and side surfaces 31e and is of a box type rectangular in the longitudinal and transverse sections. Upon the upper surface 31c of the cartridge 31 are formed projections 33, 34, 35, 36, and 37 in two rows extending longitudinally of the cartridge and a transverse projection 38 thereby forming a slot 31f into which is loosely fitted a projection 32a of a cartridge insertion chamber 32 when the cartridge 31 is inserted therein. One end of the projection 35 is coplanar with the front end surface 31a while one end of the projection 37 is coplanar with the rear end surface 31b. The projections 35 and 37 are spaced apart from each other and the projection 36 is interposed therebetween in spaced apart relation with both of the projections 35 and 37. The projection 33 in the other row has a length equal to the spacing between the projections 35 and 36 while the projection 34 has a length equal to the spacing between the projections 36 and 37. The projection 38 provides a stop or end surface 38a of the slot 31f and is connected with the projection 37 in the form of T. The distance from the end surface 38a and the rear end surface 31b is substantially equal to the spacing between the transverse projection 38 and the projection 34. The projection or key 32a is disposed at the opening of the insertion chamber 32 or at a position adjacent thereto in such a manner that when the cartridge 31 is inserted and set to its operative position, the projection or key 32a abuts against the end surface 38a of the slot 31f or located adjacent thereto. The insertion chamber 32 may be formed by continuous or spaced apart four side walls so as to have a predetermined insertion depth and a cross section corresponding to that of the cartridge. The height of the insertion chamber 32 is the height of the cartridge 31 plus that of the projection. That is, the insertion chamber 32 is so formed as to hold securely in position the inserted cartridge 31. As in the case of the first embodiment, the cartridge 31 may be inserted into the chamber 32 only in case of the relative position as shown in FIG. 3. For example, the inverted or upside-down cartridge will not be inserted since the projection or key 32a abuts against the front end surface 31a while the cartridge 31 inserted from the rear end surface 31b will be soon stopped since the projection or key 32a abuts against the transverse projection 38.
As described hereinabove, the projections 33, 34, 35, 36 and 37 are arranged in two rows and in zigzag form and the spacings between the two adjacent projections in one row are substantially equal to the lengths of the projections in the other row and in opposed relation with said spacings respectively. The reason is for facilitating the fabrication of dies for molding the cartridges and the molding operation so as to reduce the cost and giving them the better exterior appearance since by facilitating the removal of the mold in the transverse direction, that is from one side surface to the other, the number of dies required to the minimum.
In the second embodiment described above, the slot 31f is formed upon the upper surface 31c, but the slot may be formed upon the bottom surface while the projection or key 32a may be extended from the inner surface of the chamber 32 opposing to the bottom surface 31e. The end surface 38a may be provided by one wall 49a of a large projection 49 which terminates at the rear end surface 41b as shown in FIG. 4. Furthermore, the outer surfaces of the projections 33, 34, 35, 36 and 37 are not required to be disposed in coplanar relation with the side surface 31e. This arrangement is shown in FIG. 5 in which the outer surfaces of projections 53, 54, 55 and 56 are formed inwardly of the side surfaces 51e.
Referring to FIG. 6, a cartridge 61 is generally box-shaped having the rectangular longitudinal and transverse cross-sectional views and a front end surface 61a, a rear end surface 61 b, an upper surface 61c, a bottom surface 61d and side surfaces 61e. The side 61f formed by the intersection of the upper surface 61c and one side surface 61e has a bevel 61g extending from the front end surface 61a to a position adjacent to the rear end surface 61b. The length of the bevel 61g is equal to the insertion length of the cartridge 61, and an insertion chamber 62 is provided with a bevel 62a corresponding to the bevel 61g of the cartridge 61. The cartridge 61 must be inserted in the cartridge chamber 62 from the front end surface 61 a so as to engage the bevel 61g with the bevel 62a of the chamber 62. When the cartridge 61 is inverted or is inserted from the rear end surface 61b, the cartridge insertion is prevented because the cartridge 61 abuts against the bevel 62a. Therefore, the correct insertion of the cartridge is ensured without any particular precaution, thus preventing the mis-insertion of the cartridge. In addition to the bevel 61g, the side 61h may be provided with a bevel (not shown) having the same length with that of the bevel 61g. The angles of the bevels may be equal to or different from each other. In this case, the cartridge chamber must be provided with two corresponding bevels. In the third embodiment described above, the bevel 62a of the chamber 62 has been shown as extending from the opening of the chamber, but the bevel 62a may be started from a position adjacent to the opening and within the chamber and the bevel 61g of the cartridge 61 may be shortened accordingly.
In the above embodiments, the cartridge has been described as having generally the female engaging portion such as slots or bevels while the cartridge chamber, as having generally the male engaging portion such as projections or keys or bevels, but it will be understood that the above arrangements may be reversed, that is the cartridge may have the male engaging portion while the cartridge chamber, the female engaging portion.
The present invention relates to a faulty insertion preventive device for cartridges and more particularly for cartridges containing therein film or the like.
In a machine such as a cartridge type cineprojector utilizing a cartridge the cartridge must be inserted into the machine in a predetermined direction. Therefore, when the cartridge is inserted in the erroneous or wrong direction, the machine will be damaged or become out of order. Thus, there have been proposed various faulty insertion preventive method and means. But the conventional methods and means are such that an operator must judge the direction of insertion by checking the configurations of the cartridge or he may try to start the insertion of the cartridge into a chamber and then see whether the cartridge has been correctly inserted or not.
SUMMARY OF THE INVENTION
In brief, the present invention provides a faulty insertion preventive device for cartridges characterized in that a projection is formed adjacent to the opening of a cartridge insertion chamber of a machine so as to extend beyond an imaginary opening defined by the upper, lower and side surfaces of said chamber; a longitudinal recess is formed in a cartridge for engagement with said projection when inserted; and stop means is disposed at the trailing or rear end of said recess in abutment or substantially abutment relation with said projection when inserted.
According to one embodiment of the present invention, the projection within the chamber consists of one protrusion; the recess of the cartridge consists of slots formed in the upper surface and/or one side surface of the cartridge; and said stop means is a projection extending across said slots at the trailing ends thereof. When the cartridge is inserted its full extent, the stop projections abut or substantially abut against the projection of the cartridge chamber. If the cartridge is to be inserted into the chamber in the reverse or wrong direction, the projection of the chamber abuts against the stop projection of the cartridge or the surface of the cartridge so that the cartridge is not permitted to be inserted. Thus, a faulty insertion may be securely prevented.
According to another embodiment of the present invention, said slot is defined by a plurality of spaced apart projections arranged in two rows. This arrangement will facilitate the fabrication of the cartridges.
According to a further embodiment of the present invention, said recess of the cartridge is a bevel formed along one longitudinal side of the cartridge while said projection in said cartridge chamber is also a bevel corresponding to the first mentioned bevel of the cartridge and extending from the opening or a portion adjacent thereto of the cartridge chamber. This arrangement is most advantageous in simplifying the fabrication steps as the configurations are very simple.
One of the objects of the present invention is to prevent completely the faulty insertion of the cartridge.
Another object of the present invention is to provide a faulty insertion preventive device for cartridges which gives a warning of a faulty insertion or mis-insertion to an operator at the instant when he tries to insert the cartridge.
A further object of the present invention is to provide a faulty insertion preventive device for cartridges in which the cartridge and its insertion chamber have simple configurations and constructions.
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the illustrative embodiments thereof with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first embodiment of the present invention;
FIGS. 2A, 2B and 2C are perspective views illustrating various modifications of the end or stop face of a slot formed in one surface of the cartridge;
FIG. 3 is a perspective view of another embodiment of the present invention;
FIG. 4 is a perspective view illustrating a modified construction of the end or stop of the slot of the cartridge;
FIG. 5 is a perspective view illustrating a modification of the projections of FIG. 4; and
FIG. 6 is a perspective view of a third embodiment of the present invention .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a cartridge generally indicated by 1 is inserted into an insertion chamber or recess 2 of a cartridge type cineprojector, and has a front end surface 1a, a rear end surface 1b, an upper surface 1c, a bottom surface 1d, and side surfaces 1e. The cartridge 1 is generally a box rectangular in both of the longitudinal and transverse cross sections. The cross-sectional area and configuration of at least the opening or the portion adjacent thereto of the chamber correspond to those of the cartridge so as to securely hold it in position when inserted. A key 2a is disposed at the inner upper surface adjacent to the opening of the insertion chamber 2 while a key slot 1f is formed in the upper surface 1c of the cartridge 1 and the key 2a is fitted in this slot 1f for guiding the cartridge when inserted. The length of the slot 1f is such that when the cartridge 1 is inserted into the insertion chamber 2 so as to be set to an operative position, the key 2a abuts against the end wall 1ga of the slot 1f or is located at a position adjacent thereto. In the embodiment shown in FIG. 1, the end surface 1ga is formed by a transverse wall 1g and a short slot 1h having the same width and depth as that of the slot 1f is formed from the transverse wall 1g to the rear end face 1b.
When the cartridge 1 with the construction described above is attempted to be inserted into the insertion chamber 2 with the bottom surface 1d facing upwardly, the cartridge 1 insertion into the chamber 2 is not possible because the bottom surface 1d has no slot into which is fitted the key 2a. When the cartridge 1 is inserted from its rear end surface 1b into the chamber 2 with the bottom surface 1d directed upwardly, the cartridge is not permited to be inserted for the previously presented reason. When the cartridge 1 is inserted from its rear end surface 1b with the upper surface 1c directed upwardly, the key 2a fits into the short slot 1h formed in the upper surface 1c but it will soon abut against the transverse wall 1g so that the cartridge will not be permitted to advance further. Therefore, it will be seen that the cartridge 1 may be only inserted into the insertion chamber 2 correctly when the cartridge 1 is inserted from the front end surface 1a with the upper surface 1c facing upwardly and consequently the slot 1f directed upwardly so that an operator may correctly insert the cartridge 1 without any particular precaution.
It will be understood that the slot 1f may be formed in the bottom surface 1d, or side surfaces 1e instead of the upper surface 1c while the key 2a of the insertion chamber 2 may be disposed so as to accordingly oppose the slot 1f. Furthermore, the slot 1f may be formed in the upper surface 1c and one of the side surfaces 1e or in the bottom surface 1d and one of the side surfaces 1e while two keys 2a may be provided for engagement with these slots. In FIG. 1, the key 2a is shown as a screw having a head, but any other suitable key means may be formed integrally or independently of the insertion chamber 2. As shown in FIG. 2A, the end face 1ga of the slot 1f serving as a stop for the key 2a may be replaced with a wall 1i spaced apart from the inner surfaces of the slot 1f so as to provide an end face lia. Alternately, the end face 1ga may be replaced with an end face 1ja of a wall 1j extending from the end of the slot 1f to the rear end surface 1b. As shown in FIG. 2C, a circular projection 1k may be formed in the slot 1f for providing the end face 1ka as a stop. Thus, it will be seen that any suitable means may be provided as stop for the key 2a.
Referring to FIG. 3, a cartridge 31 of the present invention has a front end surface 31a, a rear end surface 31b, an upper surface 31c, a bottom surface 31d and side surfaces 31e and is of a box type rectangular in the longitudinal and transverse sections. Upon the upper surface 31c of the cartridge 31 are formed projections 33, 34, 35, 36, and 37 in two rows extending longitudinally of the cartridge and a transverse projection 38 thereby forming a slot 31f into which is loosely fitted a projection 32a of a cartridge insertion chamber 32 when the cartridge 31 is inserted therein. One end of the projection 35 is coplanar with the front end surface 31a while one end of the projection 37 is coplanar with the rear end surface 31b. The projections 35 and 37 are spaced apart from each other and the projection 36 is interposed therebetween in spaced apart relation with both of the projections 35 and 37. The projection 33 in the other row has a length equal to the spacing between the projections 35 and 36 while the projection 34 has a length equal to the spacing between the projections 36 and 37. The projection 38 provides a stop or end surface 38a of the slot 31f and is connected with the projection 37 in the form of T. The distance from the end surface 38a and the rear end surface 31b is substantially equal to the spacing between the transverse projection 38 and the projection 34. The projection or key 32a is disposed at the opening of the insertion chamber 32 or at a position adjacent thereto in such a manner that when the cartridge 31 is inserted and set to its operative position, the projection or key 32a abuts against the end surface 38a of the slot 31f or located adjacent thereto. The insertion chamber 32 may be formed by continuous or spaced apart four side walls so as to have a predetermined insertion depth and a cross section corresponding to that of the cartridge. The height of the insertion chamber 32 is the height of the cartridge 31 plus that of the projection. That is, the insertion chamber 32 is so formed as to hold securely in position the inserted cartridge 31. As in the case of the first embodiment, the cartridge 31 may be inserted into the chamber 32 only in case of the relative position as shown in FIG. 3. For example, the inverted or upside-down cartridge will not be inserted since the projection or key 32a abuts against the front end surface 31a while the cartridge 31 inserted from the rear end surface 31b will be soon stopped since the projection or key 32a abuts against the transverse projection 38.
As described hereinabove, the projections 33, 34, 35, 36 and 37 are arranged in two rows and in zigzag form and the spacings between the two adjacent projections in one row are substantially equal to the lengths of the projections in the other row and in opposed relation with said spacings respectively. The reason is for facilitating the fabrication of dies for molding the cartridges and the molding operation so as to reduce the cost and giving them the better exterior appearance since by facilitating the removal of the mold in the transverse direction, that is from one side surface to the other, the number of dies required to the minimum.
In the second embodiment described above, the slot 31f is formed upon the upper surface 31c, but the slot may be formed upon the bottom surface while the projection or key 32a may be extended from the inner surface of the chamber 32 opposing to the bottom surface 31e. The end surface 38a may be provided by one wall 49a of a large projection 49 which terminates at the rear end surface 41b as shown in FIG. 4. Furthermore, the outer surfaces of the projections 33, 34, 35, 36 and 37 are not required to be disposed in coplanar relation with the side surface 31e. This arrangement is shown in FIG. 5 in which the outer surfaces of projections 53, 54, 55 and 56 are formed inwardly of the side surfaces 51e.
Referring to FIG. 6, a cartridge 61 is generally box-shaped having the rectangular longitudinal and transverse cross-sectional views and a front end surface 61a, a rear end surface 61 b, an upper surface 61c, a bottom surface 61d and side surfaces 61e. The side 61f formed by the intersection of the upper surface 61c and one side surface 61e has a bevel 61g extending from the front end surface 61a to a position adjacent to the rear end surface 61b. The length of the bevel 61g is equal to the insertion length of the cartridge 61, and an insertion chamber 62 is provided with a bevel 62a corresponding to the bevel 61g of the cartridge 61. The cartridge 61 must be inserted in the cartridge chamber 62 from the front end surface 61 a so as to engage the bevel 61g with the bevel 62a of the chamber 62. When the cartridge 61 is inverted or is inserted from the rear end surface 61b, the cartridge insertion is prevented because the cartridge 61 abuts against the bevel 62a. Therefore, the correct insertion of the cartridge is ensured without any particular precaution, thus preventing the mis-insertion of the cartridge. In addition to the bevel 61g, the side 61h may be provided with a bevel (not shown) having the same length with that of the bevel 61g. The angles of the bevels may be equal to or different from each other. In this case, the cartridge chamber must be provided with two corresponding bevels. In the third embodiment described above, the bevel 62a of the chamber 62 has been shown as extending from the opening of the chamber, but the bevel 62a may be started from a position adjacent to the opening and within the chamber and the bevel 61g of the cartridge 61 may be shortened accordingly.
In the above embodiments, the cartridge has been described as having generally the female engaging portion such as slots or bevels while the cartridge chamber, as having generally the male engaging portion such as projections or keys or bevels, but it will be understood that the above arrangements may be reversed, that is the cartridge may have the male engaging portion while the cartridge chamber, the female engaging portion.