Disc cartridge of reduced size

A disc cartridge reduced in size and thickness and yet exhibiting sufficient strength. The disc cartridge includes a main body unit of the cartridge including upper and lower halves in which is housed an optical disc. A tubular section is formed in one of two areas delimited by an upstanding peripheral wall section and a housing forming wall section formed on a lateral side of the lower half with the tubular section being in continuation to the upstanding peripheral wall section and the housing forming wall section. The upper half includes a tubular abutment support abutted against the tubular section with the tubular abutment support connecting to the upstanding peripheral wall section and the housing forming wall section of the upper half. The upper and lower halves are unified together to form the main body unit of the cartridge.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a disc cartridge having housed therein a disc-shaped recording medium, such as an optical disc.

This application claims priority of Japanese Patent Application No. 2004-013603, filed on Jan. 21, 2004, the entirety of which is incorporated by reference herein.

2. Description of Related Art

Up to now, a disc cartridge, housing a disc-shaped recording medium, such as an optical disc, and loaded on a recording and/or reproducing apparatus with the disc-shaped recording medium rotatably housed therein, is in widespread use. With such disc cartridge, the disc-shaped recording medium is housed in a main body unit of the cartridge to protect the disc-shaped recording medium to assure facilitated lading/unloading of the disc for the recording and/or reproducing apparatus.

With this disc cartridge, in which the disc-shaped recording medium, housed in the main body unit of the cartridge, needs to be loadable on the recording and/or reproducing apparatus, the main body unit of the cartridge is provided with a driving opening for facing a turntable of a disc rotating driving mechanism for rotationally driving the disc-shaped recording medium, and with a recording and/or reproducing aperture for exposing a portion of the signal recording area of the disc-shaped recording medium to outside across the inner and outer rims thereof.

The disc cartridge is provided with a shutter member for opening/closing at least the recording and/or reproducing aperture for protecting the disc-shaped recording medium housed in the main body unit of the cartridge.

With this disc cartridge, the main body unit of the cartridge, housing the disc-shaped recording medium therein, is made up by upper and lower halves, molded from synthetic resin, and unified together by abutting and connecting the upper and lower halves together.

The disc cartridge, used as a recording medium for the recording and/or reproducing apparatus, is loaded on the recording and/or reproducing apparatus, with the lower surface of the main body unit of the cartridge as the loading reference surface. Thus, the lower half, defining the lower surface of the main body unit of the cartridge, is provided with a driving opening, a recording and/or reproducing aperture and a positioning hole engaged by a positioning pin provided to the recording and/or reproducing apparatus for setting the loading position. The outer rims of the upper and lower halves3,4are provided with upstanding peripheral wall sections abutted to each other to form an outer peripheral wall section of the main body unit of the cartridge, and housing forming wall sections on the radially inner parts of the upstanding peripheral wall sections which, when abutted together, delimit a disc housing. These housing forming wall sections are formed in continuation or in non-continuation to the inner rim of the upstanding peripheral wall sections.

Meanwhile, with the disc-shaped recording medium, such as an optical disc, the tendency is to increase the recording density and to reduce the disc diameter in keeping up with the increased recording density. As the disc-shaped recording medium is reduced in size, the disc cartridge, housing the disc-shaped recording medium, also is to be reduced in size.

As the size of the disc cartridge is reduced, the disc cartridge is also reduced in thickness. Since the disc cartridge has to be reduced in size as the inner space for housing the disc-shaped recording medium is increased, attempts are being made to reduce the thickness of the upper and lower halves making up the main body unit of the cartridge.

The positioning holes, formed in the lower half, are formed in left-hand and right-hand areas, delimited between the housing forming wall sections and the upstanding peripheral wall sections, forming the outer peripheral wall. These areas are also reduced in thickness as is the planar surface of the lower half forming the bottom surface of the disc housing.

With the disc cartridge, reduced in size, the area delimited by the housing forming wall sections and the upstanding peripheral wall sections, is also small, such that the positioning holes are formed in proximity to the housing forming wall sections and the upstanding peripheral wall sections.

These positioning holes are engaged by positioning pins provided to the cartridge loading section of the disc recording and/or reproducing apparatus. The positioning holes are engaged by positioning pins by the disc cartridge being lowered from an elevated position onto the cartridge loading section. The disc cartridge is not lowered at this time in a horizontal position with respect to the cartridge loading section but is mostly lowered towards the cartridge loading section as the disc cartridge is inclined relative to the positioning pins. If the disc cartridge is lowered as it is inclined relative to the positioning pins, the risk is high that, as the positioning pins are engaged in the positioning holes, the distal ends of the positioning pins compress against and damage the housing forming wall sections or the upstanding peripheral wall sections. In particular, the distal ends of the positioning pins are tapered to provide for facilitated engagement thereof in the positioning holes. The housing forming wall sections or the upstanding peripheral wall sections may readily be damaged by contact with such positioning pins. With the disc cartridge, reduced in size, in which the housing forming wall sections or the upstanding peripheral wall sections are reduced in thickness as are other portions, these wall sections may readily be damaged by abutment against the positioning pins. In case the housing forming wall sections are damaged, the disc-shaped recording medium, housed in the disc housing, may not be protected properly.

In addition, as the distal ends of the positioning pins are engaged in the positioning holes, the risk is high that the thin-walled portions, carrying the positioning holes, tend to be deformed, with the result that the loading position cannot be set accurately.

The risk is also high that, in the course of the engagement of the positioning pins in the positioning holes, the positioning pins act strongly on the rim of the positioning holes, with the result that the main body unit of the cartridge may be subjected to damages, such as cracks.

With this in mind, the Patent Publication 1 discloses a solution in which a thick-walled portion is provided on the rim of the positioning holes. In the solution of the Patent Publication 1, only the rim of the positioning holes is provided with the thick-walled portion, so that it is not possible to assure sufficient strength of the vicinity of the positioning holes. In particular, it is difficult with this solution to assure sufficient strength of the main body unit of the cartridge, reduced in size and thickness, and to enable the disc cartridge to be loaded in position on the carridge loading section.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a disc cartridge by which the aforementioned problems of the conventional disc cartridge may be resolved.

It is another object of the present invention to provide a disc cartridge in which sufficient strength may be assured as the disc cartridge is reduced in size and in thickness.

It is another object of the present invention to provide a disc cartridge in which the positioning holes may be correctly engaged by the positioning pins of the Recording and/or reproducing apparatus.

For accomplishing the above object, the present invention provides a disc cartridge comprising an upper half and a lower half abutted and connected to each other to form a main body unit of the cartridge for rotationally housing a disc therein, wherein there are formed an upstanding peripheral wall section on the outer periphery of the upper half, and an upstanding peripheral wall section on the outer periphery and the lower half, with the two upstanding peripheral wall sections being abutted to each other to form a peripheral wall section of the main body unit of the cartridge, there being formed a housing forming wall section on each of the inner surfaces of the upper and lower halves, the housing forming wall sections being abutted to each other to form a disc housing adapted to hold the disc therein. The lower half includes a first tubular section in one of areas delimited by the upstanding peripheral wall section and the housing forming wall section thereof, the first tubular section including a circular first positioning hole, the lower half also including a second tubular section in the other area, the second tubular section having an oblong second positioning hole, at least the second tubular section being formed in continuation to the upstanding peripheral wall section and/or the housing forming wall section of the lower half. The upper half includes tubular first and second abutment supports, abutted against the first and second tubular sections. At least the second abutment support is formed in continuation to the upstanding peripheral wall section and/or the housing forming wall section of the upper half. The upper and lower halves are unified together to form a main body unit of the cartridge by the upstanding peripheral wall sections and the housing forming wall sections thereof abutting against each other and by the first and second tubular sections compressing and abutting against the first and second abutment supports.

Preferably, the lower half includes a driving opening faced by rotation driving means adapted for rotationally driving the disc held in the disc housing, and a recording and/or reproducing aperture faced by recording and/or reproducing means for recording and/or reproducing the information for the disc.

Preferably, the first tubular section provided to the lower half is engaged with the tubular first abutment support provided to the upper half to prescribe an abutment reference position for the upper and lower halves.

Preferably, an abutment step abutting against the distal end of the first tubular section provided to the lower half is formed in the tubular second abutment support provided to the upper half.

Preferably, the upper and lower halves are formed of synthetic resin and the distal ends of the upstanding peripheral wall sections, abutted against each other, are welded together.

Preferably, the main body unit of the cartridge has a side opposite to a side provided with the first and second positioning holes, with the center of the disc in-between, as an inserting side into the disc recording and/or reproducing apparatus, and the lateral side corresponding to the inserting side is a substantially semicircular arcuate section with the center of the disc held in the main body unit of the cartridge as the center of the arc.

Preferably, the portions of the upstanding peripheral wall sections lying on the sides of the upper and lower halves form the outer peripheral wall section of the main body unit of the cartridge and a portion of the disc housing.

Preferably, the main body unit of the cartridge provided with the first and second positioning holes is a back side and the lateral surface of the back surface is a curved section having a curvature smoother than that of the arcuate section on the inserting side.

The present invention also provides a disc cartridge including a disc, an upper half and a lower half abutted and connected to each other to form a main body unit of the cartridge adapted for rotatably housing the disc therein, with the upper and lower halves each having an inserting end in the form of a substantially semi-circular arc, having the center of the disc as the center of the arc, and a back side opposite to the inserting end being curved with a curvature smoother than the curvature of the arc of the inserting end. There are formed an upstanding peripheral wall section on the outer periphery of the upper half, and an upstanding peripheral wall section on the outer periphery and the lower half, with the two upstanding peripheral wall sections being abutted to each other to form a peripheral wall section of the main body unit of the cartridge. There is formed a housing forming wall section on each of the inner surfaces of the upper and lower halves, with the housing forming wall sections being abutted to each other to form a disc housing adapted to hold the disc therein. The lower half includes a driving opening faced by rotation driving means adapted for rotationally driving the disc held in the disc housing, and a recording and/or reproducing aperture faced by recording and/or reproducing means for recording and/or reproducing the information for the disc. The lower half includes a first tubular section in one of areas delimited by the upstanding peripheral wall section and the housing forming wall section thereof. The first tubular section includes a circular first positioning hole. The lower half also includes a second tubular section in the other area, the second tubular section having an oblong second positioning hole, at least the second tubular section being formed in continuation to the upstanding peripheral wall section and/or the housing forming wall section of the lower half. The upper half includes tubular first and second abutment supports, abutted against the first and second tubular sections, at least the second abutment support being formed in continuation to the upstanding peripheral wall section and/or the housing forming wall section of the upper half. The upper and lower halves are unified together to form a main body unit of the cartridge by the upstanding peripheral wall sections and the housing forming peripheral wall section and/or the housing forming wall sections of the lower wall sections thereof abutting against each other and by the first and second tubular sections compressing and abutting against the first and second abutment supports.

With the disc cartridge according to the present invention, in which at least one of the first and second tubular sections, provided to the lower half, and carrying first and second positioning holes, is connected to the upstanding peripheral wall section and/or the housing forming wall sections, the tubular sections and the near-by portions thereof are increased in strength. Moreover, since the first and second tubular sections are abutted against the first and second abutment supports of the upper half, the positioning holes are deeper in depth. In addition, the first and second tubular sections may be maintained in the vertical positions relative to the plane of the main body unit of the cartridge to assure correct engagement in the positioning holes of the positioning pins provided to the disc recording and/or reproducing apparatus. The result is that loading with correct positioning on the disc recording and/or reproducing apparatus may be made with safe loading operation with the minimum risk of damages during loading.

According to the present invention, the strength of the positioning holes and the near-by portions may be assured, thus achieving strength and improved reliability of the disc cartridge.

Since the first tubular section, provided to the lower half, serves as a reference in prescribing the abutment reference position in abutting and connecting the upper and lower halves, the upper and lower halves may be connected to each other correctly without position deviations.

Moreover, according to the present invention, there is provided reference in prescribing the abutment reference position, while the upper and lower halves are formed of synthetic resin and the upstanding peripheral wall sections are welded and connected to each other, the disc cartridge, reduced in size, may be manufactured accurately and reliably.

Since the surface of the disc cartridge, inserted into the recording and/or reproducing apparatus, is a substantially semi-circular arcuate section, having the center of the disc-shaped recording medium, housed in the main body unit of the cartridge, as the center of the arc, the disc cartridge may further be reduced in size in keeping with the disc-shaped recording medium housed therein.

Other objects and specified advantages of the present invention will become more apparent from the following description especially when read in conjunction with the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A disc cartridge according to the present invention is now specifically explained with reference to the drawings.

The disc cartridge1according to the present invention includes a disc-shaped recording medium, such as an optical disc2, rotatably housed therein. Referring toFIGS. 1 and 2, the disc cartridge1includes a main body unit of the cartridge5, made up by an upper half3and a lower half4, abutted together as a pair, and has the optical disc2rotatably housed in the main body unit of the cartridge5.

The disc cartridge1according to the present invention has housed therein the optical disc2, having recorded thereon program data or video data for executing e.g. a TV game, and is formed to an extremely small size. The disc cartridge1has housed therein a small-sized disc, that is the optical disc2, that can be held in the palm of a user's hand.

Referring toFIGS. 1 to 3, the main body unit of the cartridge5, forming the disc cartridge1, has its front side, as one of its lateral sides, operating as an inserting end into a disc recording and/or reproducing apparatus, formed as an arcuate section7. The disc cartridge1is adapted for being introduced into and detached from the disc recording and/or reproducing apparatus. This arcuate section7is substantially of a semicircular profile, with a constant radius R1about the center of the optical disc2, housed in a disc housing section6of the main body unit of the cartridge5, as a center P0, as shown inFIG. 2. That is, the arcuate section7is formed as a semicircle substantially in register with a semicircular portion of the optical disc2housed in the main body unit of the cartridge5.

The opposing lateral sides of the main body unit of the cartridge5, contiguous to the arcuate section7, are formed as lateral sides8,9, while the back sides thereof, opposing to the arcuate section7, are formed as a smoothly uniformly curved section10.

With the disc cartridge1according to the present invention, the front side thereof, operating as an inserting side end, is formed as a substantially semi-circular arcuate section7, curved more acutely than other sides, so that insertion thereof into a disc recording and/or reproducing apparatus via a cartridge inserting/ejecting opening in accordance with the slot-in system may be discerned extremely readily. In particular, in the case of the disc cartridge1, reduced in size such that it can be held within the palm of the user's hand, the inserting direction thereof can be sensed by the hand feel when the disc cartridge is held with hand, such that the disc cartridge can be loaded correctly in the disc recording and/or reproducing apparatus as mistaken insertion is prevented from occurrence. In addition, the disc cartridge1can be inserted readily and reliably into the disc recording and/or reproducing apparatus of the slot-in system.

Moreover, the disc cartridge1according to the present invention has its inserting end side formed substantially as the semi-circular arcuate section7, while having the back side opposing to the arcuate section7as the curved section10, and hence the optical disc2housed therein may further be reduced in size.

The upper and lower halves3,4, making up the main body unit of the cartridge5by being abutted and connected together, are hereinafter explained in more detail.

The upper and lower halves3,4used are prepared by molding a synthetic resin material, such as polycarbonate resin or ABS resin.

Referring toFIGS. 4 and 5, there is formed, in the center part of the lower half4, forming the lower surface side of the main body unit of the cartridge5, a circular center opening12for exposing a center opening11formed in the optical disc2housed in the main body unit of the cartridge5and a rim part of the center opening to outside. Into this center opening12is intruded e.g. a turntable forming a part of a disc rotating driving mechanism provided to the disc recording and/or reproducing apparatus on which to load the disc cartridge1. That is, the center opening12operates as a driving opening into which is intruded a part of the mechanism for rotationally driving the optical disc2.

Referring toFIGS. 2 to 5, an aperture for the head part13, operating as a recording and/or reproducing aperture, is formed in the lower half4. The aperture for the head part13is formed towards the lateral side8of the main body unit of the cartridge5, and is extended from a site close to the center opening12up to the lateral side8as a rectangular aperture. That is, the aperture for the head part13is formed as a rectangle of a size sufficient to expose the portion of the signal recording area of the optical disc2to outside across the inner and outer rims of the disc. The aperture for the head part13is formed by opening the side thereof on the lateral side8, as shown inFIG. 4. By opening the lateral side8of the aperture for the head part13in this manner, the scanning area of the head part may be extended up to the outermost rim of the optical disc2, and hence the signal recording area of the optical disc2may be increased to increase the recording capacity thereof. Since the aperture for the head part13is not contiguous to the center opening12and is separated therefrom by a bridge-like connecting portion, thus assuring mechanical strength of the lower half4.

The surface of the upper half3facing the optical disc2is a planar surface, not having e.g. an opening, as shown inFIG. 1. The upper half3is abutted and connected to the lower half4to form an upper surface of the main body unit of the cartridge5.

The abutting surface sides of the upper and lower halves3,4are abutted and connected to each other to form upstanding peripheral wall sections16,17which are abutted and connected to each other to form an outer peripheral wall section15of the main body unit of the cartridge5. The upstanding peripheral wall sections16,17are formed for extending along the outer rim parts of the upper and lower halves3,4, as shown inFIGS. 5 and 6. On the abutting surface sides of the semi-circular arcuate section7of the upper and lower halves3,4of the peripheral wall sections16,17, there are formed plural engaging recesses18and plural mating engaging lugs19. A set of the engaging recess18and the mating engaging lug19is formed at a most protuberant center position in the transverse direction of the arcuate section7, and two sets of the engaging recesses18and the mating engaging lugs19are formed symmetrically in the left-and-right direction about the center set as center.

The engaging recesses18are formed in the upper half3, while the mating engaging lugs19are formed on the lower half4. The engaging recesses18are formed by cutting off the inner rim side of the upstanding peripheral wall section16of the upper half3. The mating engaging lugs19are formed on the distal end of the upstanding peripheral wall section17of the lower half4. On the distal ends of the mating engaging lugs19are protuberantly formed welding ribs20, as shown inFIG. 7.

On the distal ends of the portions of the upstanding peripheral wall sections16,17lying in the areas of the upper and lower halves3,4forming the curved section10are formed engaging steps16aand mating engaging lugs17a, as shown inFIG. 8. The engaging steps16aare provided on the upper half3, while the engaging steps16aare formed on the lower half4. The engaging steps16aare formed by cutting off the inner peripheral side of the upstanding peripheral wall section16of the upper half3, while the mating engaging lugs17aare formed on the distal end of the upstanding peripheral wall section17of the lower half4. A welding web20ais protuberantly formed on the distal end of the upstanding peripheral wall section17, as shown inFIG. 8. A plural number of the welding ribs20aare formed at a suitable spacing on the distal ends of the mating engaging lugs17a, as shown inFIG. 5.

The upstanding peripheral wall sections16,17are fused together to form outer peripheral wall section15by engaging the engaging recesses18with the mating engaging lugs19, engaging and abutting the engaging steps16amating engaging lugs17awith each other and by fusing the welding ribs20,20atogether, as shown inFIGS. 9 and 10. The upstanding peripheral wall sections16,17are fused together by applying ultrasonic waves to and thereby fusing the welding ribs20,20a.

On the inner surface sides of the upper and lower halves3,4, there are formed arcuate-shaped housing forming wall sections21,22, which are abutted against each other to delimit a disc housing section6, as shown inFIGS. 5 and 6. These housing forming wall sections21,22are formed on the back surface side forming the curved section10of the main body unit of the cartridge5and are formed to an arcuate profile in continuation to the upstanding peripheral wall sections16,17forming the arcuate section7on the front side of the main body unit of the cartridge5. The housing forming wall sections21,22and the upstanding peripheral wall sections16,17are abutted against one another to delimit the circular disc housing section6. The housing forming wall sections21,22and the upstanding peripheral wall sections16,17, formed for encircling the outer rim of the optical disc2housed within the disc housing section6, regulate the housing section of the optical disc2housed in the housing section6, while prohibiting the foreign matter from intruding into the disc housing section6to operate as a wall for protecting the optical disc2.

On the inner surface of the lower half4, facing the upper half3, there is formed a ring-shaped disc supporting protrusion23for encircling the center opening12, as shown inFIG. 5. On the inner surface of the upper surface3, facing the lower half4, there is similarly formed a ring-shaped disc supporting protrusion24, as shown inFIG. 6. This disc supporting protrusion24is protruded at a position on the lower half4facing the disc supporting protrusion23. These disc supporting protrusions23,24carry a signal mo-recording area on the inner rim side of the optical disc2housed in the disc housing section6to prevent the signal recording area from directly contacting with the inner surfaces of the upper and lower halves3,4to protect the optical disc2.

Meanwhile, the ring-shaped disc supporting protrusion24, formed on the upper half3, is of a diameter slightly smaller than the disc supporting protrusion23formed on the lower half4.

The lower half4is provided with first and second tubular sections27,28, in which there are formed first and second positioning holes25,26, respectively. These positioning holes are adapted for being engaged by positioning pins provided to the disc recording and/or reproducing apparatus when the disc cartridge1is loaded on the disc recording and/or reproducing apparatus, as shown inFIGS. 5 and 11. These first and second tubular sections27,28are formed provided on both back surface sides of the curved section10, as shown inFIGS. 3 and 4. That is, the first and second tubular sections27,28are formed in lest-hand and right-hand side areas encircled by back side upstanding peripheral wall section17forming the curved section10of the main body unit of the cartridge5and the housing forming wall section22, as shown inFIG. 5.

The first and second positioning hole25, provided to the first tubular section27is formed as an opening of a circular cross-section, in order that a mounting reference of the disc cartridge1to the cartridge mounting section maybe prescribed by the opening engaging with the positioning pin of the circular cross-section provided to the disc recording and/or reproducing apparatus. The first tubular section27is formed to a tubular form with a circular cross-section to the shape of the first positioning hole25formed therein. The second positioning hole26is formed as an oblong hole having a long diameter along the transverse direction across the lateral sides8,9of the main body unit of the cartridge5, in order that, when a positioning pin provided to the recording and/or reproducing apparatus is engaged in the second positioning hole26, with the first positioning hole25as a reference, the engagement position of the positioning pin may be adjusted in its engagement position in the positioning hole26, as shown inFIGS. 3 and 4. The second tubular section28is formed as a tube of an elliptical cross-section to the shape of the second positioning hole26formed therein.

An engagement lug29is provided in an area encircled by the housing forming wall section22and by the upstanding peripheral wall section17and including the second tubular section28. The engagement lug29is provided closer to the upstanding peripheral wall section17, forming the opposite side lateral surface9of the main body unit of the cartridge5, than to the second tubular section28, as shown inFIG. 5. That is, the engagement lug29is provided at a position remoter from the first tubular section27than the second tubular section28, as shown inFIG. 5.

The first tubular section27and the second tubular section28form a first positioning part and a second positioning part for setting the abutting position for the upper and lower halves3,4, respectively.

The inner surface of the upper half3is provided with a first abutment support30for engaging with the first tubular section27provided to the lower half4, and with a second abutment support31for abutment against the second tubular section28. The first and second abutment supports30,31are tubular in shape.

The upper half3is provided with an engagement support32engaged with the engagement lug29.

It is noted that the first tubular section27and the engagement lug29are formed to a height of protruding from the distal end of the upstanding peripheral wall section17, as shown inFIG. 11, so that, when the upstanding peripheral wall sections16,17are abutted together to connect the upper and lower halves3,4to each other, the first tubular section27and the engagement lug29are engaged in the first abutment support30and in the engagement support32which are formed to the same height as that of the upstanding peripheral wall section16.

The second tubular section28is formed to the same height as that of the upstanding peripheral wall section17, so that, when the upstanding peripheral wall sections16,17are abutted together to connect the upper and lower halves3,4to each other, the second tubular section28is engaged with second abutment support31, the distal end of the which is formed to the same height as that of the upstanding peripheral wall section16.

Meanwhile, the first abutment support30and the second abutment support31, provided to the upper half3, are provided in left-hand and right-hand side areas encircled by back side upstanding peripheral wall section16forming the curved section10of the main body unit of the cartridge5and the housing forming wall section21, as shown inFIG. 6. The engagement support32is provided closer to the upstanding peripheral wall section16, forming the opposite side lateral surface9of the main body unit of the cartridge5, than to the second abutment support31, as shown inFIG. 6.

When engaged with each other, the first tubular section27and the first abutment support30constitute a reference abutment position for the upper and lower halves3,4. That is, the upper half3is connected to the lower half4with the first tubular section27, provided to the lower half4, as a reference engagement position. Thus, the first tubular section27and the first abutment support30are formed to a diameter such that the two components have a tight fit with each other, as shown inFIG. 11. That is, the outer diameter of the first tubular section27is approximately equal to the inner diameter of the first abutment support30engaged by the distal end of the first tubular section27.

In the inside of the first abutment support30is formed an abutment step33, compressing against the distal end of the first tubular section27, as shown inFIG. 11. The first tubular section27has its distal end abutted against the abutment step33for engagement with the first abutment support30. Since the first abutment support30is formed in its inside with the abutment step33, the base part side towards the planar side of the upper half3may be increased in thickness to improve mechanical strength.

The first abutment support30may be formed to tubular form a, with a uniform inner diameter, without providing an inner abutment step. In this case, the first tubular section27is carried by being abutted against the planar surface of the upper half3.

The engagement support32is formed to an elliptical shape having the width-wise direction corresponding to the direction of an arrow X1inFIG. 6across the lateral sides8,9of the main body unit of the cartridge5, such that the engagement position of the engagement lug29along the transverse direction may be adjusted when the upper and lower halves3,4are abutted against each other with the first tubular section27and the first abutment support30as reference.

In abutting and connecting the upper and lower halves3,4, constructed as described above, the lower half4is carried in position by a positioning jig and, as shown inFIG. 12, the first abutment support30of the upper half3is engaged with the first tubular section27of the first tubular section27of the lower half4, while the engagement lug29of the lower half4is engaged with the engagement support32of the upper half3, and the plural engaging recesses18of the upper half3are engaged with the plural mating engaging lugs19of the lower half4to abut the upstanding peripheral wall sections16,17to each other.

The mating engaging lug19, provided to a mid position at the most protuberant position of the arcuate section7, out of the engaging lugs19of the lower half4, engaged with the engaging recesses18of the upper half3, is designed to act as a third positioning means for positioning along the direction of the arrow X2along the arc of the arcuate section7when the upper and lower halves3,4are abutted and connected to each other. The mating engaging lug19, forming a third positioning means, is designed to leave a small gap when engaged in the engaging recesses18of the upper half3. That is, the mating engaging lug19, forming the third positioning means, and the engagement recess18, engaged by this engaging lug19, are formed to high precision as shown to give a small gap D1to an enlarged scale inFIG. 13. That is, the mating engaging lug19and the engagement recess18, engaged by this engaging lug19, are formed to substantially the same widths W1, W2to permit tight engagement therebetween. Since the engagement recess18is tightly engaged with the engaging lug19, forming the third positioning means, the upper and lower halves3,4are coupled to each other in position along the arc of the arcuate section7.

The mating engaging lugs19and the engaging recesses18, other than the engaging lug19, forming the third positioning means, and the engaging recesses18, engaged by this engaging lug19, are sized to take up position deviation on engagement with each other. That is, the engaging lug19is smaller in size than the width of the engaging recesses18, or the engaging recesses18is larger in size than the engaging lug19.

The mating engaging lugs19and the engaging recesses18may be reversed in mounting positions thereof from each other. That is, the engaging lugs and the engaging recesses may be provided on the upper half3and on the lower half4, respectively. In such case, the engaging recesses18provided to the lower half4operates as the thir positioning means.

The upper and lower halves3,4are abutted against each other with the first tubular section27as an abutment reference position. The upper and lower halves3,4are positioned in the fore-and-aft direction of the main body unit of the cartridge5, in a direction of an arrow Y1perpendicular to the width-wise direction indicated by arrow X1inFIG. 12, by the engagement lug29engaging with the engagement support32, whilst the abutment position against the arcuate section7as an inserting end to the disc recording and/or reproducing apparatus may be set by the engaging recesses18and the mating engaging lugs19, operating as the third positioning means, engaging with each other.

The upper and lower halves3,4, thus abutted against each other in position, are unified together by fusing the welding ribs20provided to the distal end of the upstanding peripheral wall section17, using an ultrasonic welding unit, to form the main body unit of the cartridge5.

According to the present invention, the upper and lower halves3,4are abutted and connected to each other, as the upper and lower halves3,4are positioned at three points, that is, at the first and second positioning parts provided on both back surface sides of the curved section10of the main body unit of the cartridge5, and at a third positioning part at the center of the front side arcuate section7, so that the upper and lower halves3,4may be mounted to high accuracy with the minimum phase deviation. In particular, since the first and second positioning parts are located on the outer rim of the main body unit of the cartridge5, and are spaced apart at a larger distance from each other, the position deviation of the main body unit of the cartridge5may be reduced further to improve mounting precision further. The result is that the disc cartridge1employing this main body unit of the cartridge5is improved in mounting precision, so that the disc cartridge may be smoothly mounted to or dismounted from the recording and/or reproducing apparatus. In addition, the disc cartridge1employing this main body unit of the cartridge may be improved in appearance.

Moreover, with the disc cartridge1, since the engagement lug29, forming the second positioning unit on the lower half4, is provided at a significant distance from the first tubular section27, the position deviation in the abutment position of the upper and lower halves3,4may be reduced further. In particular, deviation in the abutment position between the tubular second abutment support31and the second tubular section28, formed around the second positioning hole26, located between the first tubular section27and the engagement lug29, may be reduced to achieve more reliable abutment.

Moreover, with the disc cartridge1according to the present invention, in which the upper and lower halves3,4may be coupled to each other, as position deviation is suppressed from occurring, the housing forming wall sections21,22, provided to the upper and lower halves3,4, may also be abutted against each other as position deviation is suppressed from occurring, so that the disc housing section6may be formed to high accuracy. The result is that protrusions that may injure the optical disc2within the disc housing section6may be suppressed from being produced to enable reliable protection of the optical disc2.

Additionally, with the disc cartridge1according to the present invention, in which the upstanding peripheral wall sections16,17forming the outer peripheral wall section15of the main body unit of the cartridge5delimits the disc housing section6, the disc cartridge1may further be reduced in size.

Meanwhile, with the disc cartridge1according to the present invention, the outer peripheral surface of the second tubular section28, delimiting the second positioning hole26formed in the lower half4, is connected via connecting portions28a,28bto the upstanding peripheral wall section17and to the housing forming wall sections22of the lower half4, as shown inFIG. 5. By connecting the second tubular section28to the upstanding peripheral wall section17and to the housing forming wall section22in this manner, the second tubular section28and the near-by portion may be improved in strength. Since the second tubular section28is formed to the same height as that of and connected to the upstanding peripheral wall section17and the housing forming wall sections22, it is possible to maintain verticality of the second tubular section28and to improve the strength of the portion of the lower half4carrying the second tubular section28.

The outer peripheral surface of the first tubular section27, provided to the lower half4, carrying the first positioning hole25, is connected to the housing forming wall sections22of the lower half4through a connection part27a, as shown inFIG. 5. That is, even in case the first tubular section27is connected on only one side to the housing forming wall sections22the first tubular section27and its near-by portion may be improved in strength. It is noted that, since the first tubular section27is formed to a larger height than the housing forming wall sections22, and is connected to this housing forming wall sections22, as shown inFIG. 11, it is possible to maintain verticality of the first tubular section27to improve the strength of the first tubular section27.

The outer peripheral surfaces of the first and second abutment supports30,31, on which are abutted the first and second tubular sections27,28, formed on the upper half3, are connected, via connecting parts30a,30b,31aand31bto the upstanding peripheral wall section16and to the housing forming wall section21of the upper half3, as shown inFIG. 6. By connecting the first and second abutment supports30,31to the upstanding peripheral wall section16and to the housing forming wall section21in this manner, the first and second abutment supports30,31and the near-by portion may be improved in strength. Since the first and second abutment supports30,31are formed to the same height as that of and connected to the upstanding peripheral wall section16and the housing forming wall sections21, it is possible to maintain verticality of the first and second abutment supports30,31and to improve the strength of the portion of the upper half3carrying the first and second abutment supports30,31.

With the disc cartridge1according to the present invention, in which, when the upper and lower halves3,4are abutted and connected to each other, the first and second tubular sections27,28and the first and second abutment supports30,31on the upper half side are abutted against one another to form continuous tubular sections, the depths D1and D2of the first and second positioning holes25,26, formed in the first and second tubular sections27,28, may be of a depth approximately equivalent to the thickness of the main body unit of the cartridge5, as shown inFIG. 11. Moreover, since the first and second tubular sections27,28and the first and second abutment supports30,31on the upper half side are abutted against one another to form continuous tubular sections, the verticality with respect to the plane of the main body unit of the cartridge5may be maintained to realize correct engagement between the positioning pins on the side of the disc recording and/or reproducing apparatus and the first and second positioning holes25,26. The result is that the disc cartridge1may be loaded in position on the disc recording and/or reproducing apparatus, whilst safe loading may be achieved with minimum risk of occurrence of damages during loading.

In addition, since the portions of the disc cartridge1carrying the first and second positioning holes25,26engaged by the positioning pins of the disc recording and/or reproducing apparatus are improved in strength, there is only little risk of injury to rim portions of the first and second positioning holes25,26due to abutment of the positioning pins against such rim portions.

A shutter member35for opening/closing the aperture for the head part13is mounted to the main body unit of the cartridge5, as shown inFIGS. 1 to 3. This shutter member35is formed by punching and bending a thin metal sheet or by forming a synthetic resin material. The shutter member35is made up by a rectangular flat-plate shutter part36sized large enough to cover up the aperture13and a cartridge support part37formed on the distal end of the shutter part36, as shown inFIGS. 2 and 3. The distal end of the shutter part36is provided with a guide support part39carried by a shutter guide part39carried by the main body unit of the cartridge5. The shutter guide part39is formed by bending the distal end of the shutter part36towards the main body unit of the cartridge5, as shown inFIGS. 14 and 15.

Meanwhile, the shutter member35is carried for movement in the directions indicated by arrow A or B inFIGS. 1 and 2, for opening/closing the aperture13, by having a slide guide part41carried by the cartridge support part37. The slide guide part41is formed on the upper half3over a gamut of movement of the shutter member35adapted for opening/closing the aperture13. This slide guide part41is formed in a portion of the upstanding peripheral wall section16, provided to the upper half3, and is designed for carrying the shutter member35within a range of the lateral side8of the main body unit of the cartridge5.

The cartridge support part37, provided to the shutter member35, includes a connecting piece42, formed upright from the proximal end of the shutter part36, and a first support piece43is formed by bending the distal end of the connecting piece42towards the shutter part36, as shown inFIGS. 14 and 15. On one side of the connecting piece42, there is provided a second support piece44by bending the connecting piece in an L-shape at a location lower in height than the first support piece43. The distal end of the second support piece44is bent to form an engagement piece45protruded towards the first support piece43. On the opposite side of the connecting piece42, there is formed a spring retention piece46for protruding towards the shutter part36. The spring retention piece46is provided at the same height level as that of the second support piece44.

This spring retention piece46is engaged by a portion of the torsion coil spring48forming a bi-directional biasing mechanism designed for selectively biasing the shutter member35mounted to the main body unit of the cartridge5in a direction of closing or opening the aperture13.

On the proximal side of the spring retention piece46, there is formed an engagement piece49projected towards the first support piece43.

A slide guide unit41for movably carrying the shutter member35is formed as a part of the upstanding peripheral wall section16, provided to the upper half3, as shown inFIGS. 14 and 16. This slide guide unit41is made up by a guide groove51, formed in the outer lateral side of the upstanding peripheral wall section16, parallel to the movement direction of the shutter member35, as shown inFIG. 14, and by a guide rail52, carried by and between first and second support pieces43,44, as shown inFIG. 16.

The surface of the guide rail52, facing outwards, is a surface perpendicular to the plane of the upper half3, as shown inFIGS. 14 and 16. This surface faces the inner lateral surface of the connecting piece42, forming the slide guide unit41, and forms a first guide wall section53, adapted for guiding the direction of movement of the shutter member35. The inwardly facing surface of the guide rail52is a surface extending parallel to the first guide wall section53. This surface faces the second support piece44and the spring retention piece46to form a second guide wall section54adapted for guiding the direction of movement of the shutter member35. The distal end face of the guide rail52extends at right angles to the first and second guide wall sections53,54. This end face, facing the second support piece44and the spring retention piece46, forms a third guide wall section55for guiding the direction of movement of the shutter member35. The distal end side corner extending from the first guide wall section54to the second guide wall section55is formed as an inclined surface section56. This inclined surface section56operates as a clearance area for such a case where the engagement pieces45,49provided to the shutter member35are engaged with the second guide wall section54of the guide rail52.

For having the shutter member35carried by the above-described slide guide unit41, the shutter part36is arranged for extending on the aperture13formed in the lower half4, and the cartridge support part37is engaged by the slide guide unit41. For having the cartridge support part37carried by the slide guide unit41, the first support piece43is engaged with the guide groove51, and the engagement pieces45,49are caused to face the second guide wall section54. In this manner, the shutter member35is movably carried by the upper half3, with the guide rail52being sandwiched between the first support piece43, second support piece44and a portion of the spring retention piece46, as shown inFIGS. 13 and 14.

With the slide guide unit41, the connecting piece42faces the first guide wall section53, and the engagement pieces45,49face the second guide wall section54, while the second support piece44and the spring retention piece46face the third guide wall section55, so that movement of the shutter member35in its movement direction and in a direction perpendicular to the movement direction, that is, in a direction along the thickness of the main body unit of the cartridge5is prohibited. The result is that the shutter member35may be moved as it is guided by the slide guide unit41, without experiencing any severe wobbling.

Additionally, since the shutter member35is carried by the slide guide unit41, formed on the distal end of the upstanding peripheral wall section16, provided to the upper half3, as shown inFIGS. 16 and 17, the planar surface side of the upper half3, forming the upper surface side of the main body unit of the cartridge5, may be opened wide apart, as shown inFIG. 1. That is, the shutter member35may be mounted to the main body unit of the cartridge5, without having to expose the slide guide unit41partially on the planar surface side of the upper half3.

Meanwhile, in the disc cartridge1according to the present invention, the shutter member35is mounted for not being protruded at least from the outer peripheral surface of the main body unit of the cartridge5. Specifically, the shutter member35is mounted so as to be flush with the outer peripheral surface of the main body unit of the cartridge5. To this end, a recessed shutter slide unit58is mounted so as to be flush with the outer peripheral surface of the main body unit of the cartridge5. Thus, the recessed shutter slide unit58is formed in an area of the lower half4where the shutter member35is moved, as shown inFIGS. 2 and 3. The shutter slide unit58is of such a depth that the shutter part36is not protruded from the surface of the main body unit of the cartridge5. On the lateral surface8of the main body unit of the cartridge5, on which is moved the connecting piece42of the slide guide unit41, there is formed a recess59for the slide unit continuing to the shutter slide unit58. This recess59for the slide unit also is of such a depth that the connecting piece42is not protruded from the surface of the main body unit of the cartridge5.

In the disc cartridge1of the present embodiment, a recess for the head part61is formed on the opposite side of the shutter slide unit58, with the aperture13in-between, in continuation to the aperture13, as shown inFIGS. 2 and 3. The recess for the head part61is used for allowing the head part of the disc recording and/or reproducing apparatus, loaded with the disc cartridge1according to the present invention, to approach further to the optical disc2, and is formed to a depth deeper than the shutter slide part59.

The disc cartridge1according to the present invention is provided with a shutter guide member38for supporting the shutter guide part39, provided to the distal end of the shutter part36, preventing the shutter part36from floating from the main body unit of the cartridge5and for assuring stable movement of the shutter member35. The shutter guide member38is formed by punching a thin sheet member, and is formed of synthetic resin of the same type as the material of the upper and lower halves3,4, such as polycarbonate resin.

The shutter guide member38is used for carrying the slide guide unit39on the distal end side of the shutter part36, adapted for opening/closing the aperture13. Thus, the shutter guide member38is positioned on a plane outside of the lower half4forming the surface of the main body unit of the cartridge5, between the circular center opening12and the aperture for the had part13, and is formed to a length sufficient to carry the slide guide part39at least across the range of movement of the shutter member35.

The shutter guide member38is mounted to the main body unit of the cartridge5, as the guide support part39, formed at the distal end of the shutter part36, is intruded into a slide recess63for the slide part and as the guide support part39is carried by the shutter guide member38provided within a shutter guide member mounting recess62.

With the disc cartridge1according to the present invention, in which the main body unit of the cartridge5may be formed to high accuracy, the shutter member35, mounted to the main body unit of the cartridge5, may be moved in stability relative to the main body unit of the cartridge5, thereby reliably opening/closing the aperture for the head part13.

In the above-described disc cartridge1, the shutter member35is carried by the upper half3for opening/closing the aperture for the head part13of the lower half4. Since the upper and lower halves3,4are coupled together in a manner free from position deviation, the aperture13in the lower half4may be reliably opened/closed by the shutter member35carried by the upper half3.

The disc cartridge1according to the present invention is provided with a bi-directional biasing mechanism68for causing reliable movement of the shutter member35opening/closing the aperture13and for reliably holding the shutter member35in the position closing the aperture13or in the position opening the aperture13. This bi-directional biasing mechanism68has the function of biasing the shutter member35into movement for opening the aperture13or that for closing the aperture13, and constitutes a shutter opening/closing mechanism.

This bi-directional biasing mechanism68is formed by employing a bi-directional biasing member for selectively biasing the shutter member35in two directions, that is, in a direction of opening the aperture and in a direction of closing the aperture. Specifically, the bi-directional biasing member is a torsion coil spring48, as shown inFIGS. 14,15and18. The torsion coil spring48is mounted between the shutter member35and the main body unit of the cartridge5. This torsion coil spring48is mounted at such a position that the shutter member35is thereby moved in the direction of opening the aperture for the head part13, as shown inFIG. 18. That is, the torsion coil spring48is mounted on an upstream side such that the shutter member35is thereby moved in the direction of opening the aperture13, from the position closing the aperture.

The torsion coil spring48, forming the bi-directional biasing mechanism68, is mounted by having the distal end of one arm48aretained by an engaging part70formed on the distal end of the spring retention piece46and by having a ring part71engaged by a support pin72protuberantly formed on the inner surface of the lower half4. the ring part71is provided to the distal end of the other arm48b.

The upper half3is provided with a tubular engaging part78, in register with a support pin72of the lower half4, so as to be engaged by the distal end of the support pin72. This engaging part78is engaged by the support pin72to prevent detachment of the ring part71of the torsion coil spring48engaged with the support pin72.

When the shutter member35is in the position of closing the aperture for the head part13, the torsion coil spring48biases the shutter member in the direction indicated by arrow B inFIG. 18, in order to maintain the closed state of the aperture for the head part13. When the disc cartridge1is loaded on the disc recording and/or reproducing apparatus, and the shutter member35is moved in the direction indicated by arrow A inFIG. 18for opening the aperture for the head part13relative to the main body unit of the cartridge5, the position of a coil part, formed at a non-fixed mid position, is moved in the direction indicated by arrow A corresponding to the direction of movement of the shutter member35when the coil part48cis moved further in the direction indicated by arrow A inFIG. 18, such that the coil part surpasses the position of the support pin72lying along the direction of movement of the shutter member35, the biasing direction of the torsion coil spring48is reversed. When reversed in its biasing direction, the torsion coil spring48biases the shutter member35into movement in a direction indicate by arrow A inFIG. 17. That is, the torsion coil spring48biases the shutter member35into movement in the direction of arrow A inFIG. 17and is moved in the direction of arrow A of opening the aperture for the head part13, as shown inFIG. 19, in order to maintain the aperture for the head part13in an opened position.

When the operation of taking out, that is ejecting, the disc cartridge1, in which the shutter member35has held the aperture for the head part13in the opened position, is performed, the shutter member35is moved relative to the main body unit of the cartridge5, in the direction of arrow B inFIG. 19. The mid coil part48calso is moved in the same direction indicated by arrow B. When the shutter member35is moved further in the direction indicated by arrow B, and the coil part48chas surpassed the position of the support pin72, located in the movement direction of the shutter member35, the biasing direction of the spring is reversed. When the biasing direction is reversed, the torsion coil spring48biases the shutter member35into movement in the direction indicated by arrow B inFIG. 18. Thus, the shutter member is moved in the direction of closing the aperture for the head part13to maintain the aperture for the head part13in the closed state.

The shutter member35, biased in this manner by the torsion coil spring48forming the bi-directional biasing mechanism68is supported in the position of closing the aperture for the head part13or in the position of opening the aperture for the head part13, under the bias force of the torsion coil spring48, so that the aperture for the head part13may be reliably maintained in the closed position or in the open position.

With the above-described disc cartridge1, the shutter member35is maintained in the position of closing the aperture for the head part13by the torsion coil spring48forming the bi-directional biasing mechanism68. A shutter member lock mechanism may be provided in which a lock lever rotationally biased by a spring is provided to the spring retention piece46of the shutter member35. This lever may be turned in association operatively with the loading/unloading of the disc cartridge1to or from the disc recording and/or reproducing apparatus to lock or unlock the shutter member35.

In the lateral surface of the main body unit of the cartridge5of the disc cartridge1according to the present invention, carrying the shutter member35, there is formed a guide groove73, into which is intruded a shutter member releasing piece, provided to the disc recording and/or reproducing apparatus, as shown inFIGS. 1 and 14.

In the opposing lateral surfaces8and9of the arcuate section7of the main body unit of the cartridge5, there are formed engaging recesses75,76for loading, engaged by portions of a cartridge loading mechanism of the disc recording and/or reproducing apparatus, on which is loaded the disc cartridge1, as shown inFIGS. 1 and 2.

The lateral surface9of the main body unit of the cartridge5, there is formed an engagement recess77for ejection, engaged by a portion of the ejection mechanism provided to the disc recording and/or reproducing apparatus, as shown inFIG. 2.

In the lateral surfaces8,9or in the bottom surface of the main body unit of the cartridge5, there is formed a discrimination opening or recess for discriminating the sort of the optical disc2housed therein.

In the foregoing explanation, the present invention is applied to a disc cartridge having a semicircular inserting end to reduce the size. The present invention is, however, not limited to the above-described disc cartridge and may, for example, be applied to a disc cartridge having a rectangular-shaped main body unit of the cartridge or to a disc cartridge having a recording and/or reproducing aperture in each of the upper and lower surfaces of the main body unit of the cartridge with similar merits to those obtained with the above-described embodiments.

The disc-shaped recording medium is not limited to the optical disc. The present invention may be applied to a disc cartridge having housed therein any other suitable disc-shaped recording mediums, including magnetic discs, with merits comparable to those described above.