Magnetic recording/reproducing apparatus having a plastic chassis in which a bottom plate and side walls are integrally formed

There is provided a magnetic recording/reproducing apparatus using a plastic chassis having side walls integrally formed with a bottom plate. A cassette holder holding the cassette case moves between a loaded position and an ejected position. A pair of pins are protrudingly provided on side surfaces of the cassette holder. One pin of the pair of pins is provided on a left side surface, and the other pin is provided on a right side surface. The plastic chassis has a bottom plate and left and right side walls formed perpendicularly on the left side and the right side of the bottom plate. The bottom plate and the left and right side walls are integrally formed with each other. A pair of slots are formed on the left and right side walls, one slot of the pair of slots being formed on the left side wall, the other slot being formed on the right side wall. The cassette holder is movably supported by the pins being inserted into the respective slots between the left side wall and the right side wall. A movement of the cassette holder is guided by the slots in extending directions of the slots.

BACKGROUND OF THE INVENTION 
The present invention generally relates to a chassis made of plastics used 
for magnetic recording/reproducing apparatus, and more particularly to a 
plastic chassis of which bottom plate and side walls are integrally 
formed, a cassette holder being movably supported between the side walls. 
In conventional magnetic recording/reproducing apparatus such as video 
cassette tape recorders and digital audio cassette tape recorders, it is 
well known to mount mechanical parts, such as a cassette loading 
mechanism, a cassette tape loading/unloading mechanism and a tape driving 
mechanism, on a chassis. 
A conventional chassis is formed by aluminum die casting because of 
aluminum's rigidity and light weight. In order to mount the 
above-mentioned mechanical parts on the chassis, a pin is press fitted to 
the chassis, and a metal plate having a shaft thereon is mounted on the 
chassis. 
In the cassette tape loading/unloading mechanism, a cassette holder is 
incorporated so as to accommodate the cassette tape and move it to a tape 
loading position. The cassette holder moves in a horizontal direction and 
a vertical direction. That is, when the cassette tape is inserted into the 
cassette holder, the cassette holder moves first in the horizontal 
direction to move the cassette tape inside the apparatus, and the cassette 
holder then moves downward to move the cassette tape to the tape loading 
position. 
In order to guide a series of movements of the cassette holder, guiding 
slots are formed on left and right walls of the chassis. Pins are 
protrudingly provided on left and right surfaces of the cassette holder, 
the pins being inserted into the corresponding slots formed on the side 
walls of the chassis. Accordingly the cassette holder is supported between 
the side walls via the pins, and thus the cassette holder is movable in a 
direction along which the slots are extended. In other words, the movement 
of the cassette holder is guided in predetermined directions by a 
mechanism in which the pins are provided on the cassette holder and the 
slots are provided in the side walls of the chassis. 
In the conventional cassette tape loading/unloading mechanism, in order to 
insert the left and right pins into the corresponding slots formed on the 
side walls, an assembly method is used in which one of the left and right 
walls is fixed to a bottom plate of the chassis, and then the pins 
corresponding to the fixed side wall are inserted into the slots formed on 
the fixed side wall, and then the other side wall is fixed on the bottom 
plate while the pins corresponding to the other side wall are inserted 
into the slots formed on the other side wall. That is, if both of the side 
walls were initially formed on the bottom plate of the chassis, the 
cassette holder could not be positioned between the side walls because the 
pins would interfere with the side walls, and therefore the side walls are 
provided as a separate part from the bottom plate of the chassis. 
The side walls of the chassis may be integrally formed with the bottom 
plate of the chassis by using aluminum die casting. However, there is a 
problem in that the above-mentioned slots cannot be formed on the side 
walls with a desired accuracy by an aluminum die casting process, and thus 
even if the side walls were integrally formed with the bottom plate, 
additional parts would be required to provide the slots, or an additional 
machining of the slots on the side walls would be required. 
As mentioned above, because the bottom plate and the side walls in the 
prior art are separate parts, the number of parts of the conventional 
chassis is increased, and thus the number of assembly processes are also 
increased. Accordingly, there is a problem that a manufacturing cost of 
the chassis is high. 
SUMMARY OF THE INVENTION 
It is a general object of the present invention to provide an improved and 
useful magnetic recording/reproducing apparatus in which the 
above-mentioned problems are eliminated. 
A more specific object of the present invention is to provide a magnetic 
recording/reproducing apparatus using a plastic chassis having side walls 
integrally formed with a bottom plate. 
In order to achieve the above-mentioned objects, there is provided 
according to the present invention, a magnetic recording/reproducing 
apparatus in which a recording medium accommodated in a cassette case is 
moved between a loaded position and an ejected position, the magnetic 
recording/reproducing apparatus comprising: 
a cassette holder holding the cassette case and moving between the loaded 
position and the ejected position; 
at least one pair of pins protrudingly provided on side surfaces of the 
cassette holder, one pin of the pair of pins being provided on a left side 
surface, the other pin of the pair of pins being provided on a right side 
surface; 
a chassis, made of a plastic, having a bottom plate and left and right side 
walls being formed perpendicularly on the left side and the right side of 
the bottom plate, the bottom plate and the left and right side walls being 
integrally formed with each other; and 
at least one pair of slots formed on the left and right side walls, one 
slot of the pair of slots being formed on the left side wall, the other 
slot of the pair of slots being formed on the right side wall, 
the cassette holder being movably supported by the pins being inserted into 
the respective slots between the left side wall and the right side wall, 
the movement of the cassette holder being guided by the slots in extending 
directions of the slots. 
According to the present invention, since the chassis is formed by the 
bottom plate and the left and right side walls integrally formed with the 
bottom plate, the chassis is formed as a single part. Additionally, the 
slots are formed on the left and right side walls at the same time when 
the chassis is formed by plastic molding. Therefore, the number of parts 
need for forming the chassis is reduced, and parts needed for providing 
the slots guiding the cassette holder are eliminated. 
Other objects, features and advantages of the present invention will become 
more apparent from the following detailed description when read in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A description will now be given of an embodiment according to the present 
invention. FIGS. 1A, 1B and 1C are views of a plastic chassis which is an 
essential part of an embodiment of a magnetic tape apparatus according to 
the present invention; FIG. 1A is a left side view; FIG. 1B is a plan 
view; FIG. 1C is a front view. 
In FIGS. 1A, 1B and 1C, a chassis 1 is used for a cassette tape apparatus, 
the chassis 1 being formed of a plastic, preferably polycarbonate or ABS 
resin, as a single part. Slots 4 and 5 used for guiding a cassette holder 
6 (indicated by chain lines) are formed on a side wall 2 of the plastic 
chassis 1. Each of the slots 4 and 5 is formed, as shown in FIG. 1A, in an 
L-shape having a portion extending in a horizontal direction and a portion 
extending in a vertical direction. Similarly to the side wall 2, slots 4' 
and 5' (not shown in the figures) are formed in corresponding positions on 
a side wall 3. The slots 4 and 4' comprise a pair, and the slots 5 and 5' 
comprise another pair. It should be noted that only a left side wall 2 is 
shown in the drawings, for the sake of convenience, since the right side 
wall 3 has the same construction as the left side wall 2. 
The pins 7 and 8, protrudingly provided on the side surface of the cassette 
holder 6, engage with the corresponding slots 5 and 4, and the pins 7' and 
8' engage with the corresponding slots 5' and 4'. The pins 7 and 7' 
comprise a pair, and the pins 8 and 8' comprise another pair. A threaded 
hole is formed on an end of each of the pins 8 and 8'. The pins 7 and 7' 
are slightly longer than the pins 8 and 8'. 
When a cassette tape (not shown in the figures) is inserted into the 
cassette holder 6, a cassette moving mechanism (not shown in the figures) 
is operated so as to move the cassette holder 6 far inside of the 
apparatus. In this operation, the cassette holder 6 is moved in a 
horizontal direction by being guided by the slots 4 and 5 formed on the 
side wall 2 and the slots 4' and 5' formed on the side wall 3, and 
thereafter moved downward so as to move the cassette tape to a loaded 
position. 
In the present embodiment, a bottom plate 9 and the side walls 2 and 3 are 
integrally formed with each other to form the plastic chassis 1. The pair 
of slots 4 and 4' and the pair of slots 5 and 5' are formed at the same 
time that the chassis 1 is molded. Accordingly, the bottom plate 9 and the 
side walls 2 and 3 are formed into a single part, and no separate part to 
be mounted to the chassis 1 is needed to provide the slots 4, 4', 5 and 
5'. Accordingly, a number of parts and a number of assembling processes of 
the cassette tape apparatus can be reduced, and thus a manufacturing cost 
of the cassette tape apparatus can be reduced. 
A description will now be given of an assembling method of the cassette 
holder with the plastic chassis 1. FIG. 2 is a view showing a process for 
positioning the cassette holder 6 between the side walls 2 and 3 of the 
chassis 1. FIGS. 3 and 4 show plan views of a part of the chassis 1 for 
explaining an assembly process of the cassette holder 6 with the chassis 
1. 
As shown in FIGS. 2 and 3, the pins 7 and 8 provided on the left side 
surface of the cassette holder 6 are inserted into the corresponding slots 
5 and 4. At this time, the pins 7 and 8 are inserted into the slots 5 and 
4 while the cassette holder 6 is inclined as shown in FIG. 2. An end of 
the pin 8 is provided with the threaded hole. After the pins 7 and 8 are 
sufficiently inserted, the cassette holder 6 is positioned horizontally, 
and, as shown in FIG. 4, a bushing 11 is fitted on the pin 8 so as to be 
fixed on the end of the pin 8 by means of a screw screwed into the 
threaded hole formed on the pin 8. Thereafter, a bushing 11' is inserted 
into the slot 4' from outside the side wall 3 so as to be fitted on the 
pin 8', and the bushing 11' is fixed on the end of the pin 8' in the same 
manner as for the pin 8 and the bushing 11. Each of the bushings 11 and 
11' has a collar having a diameter greater than a width of the slots 4 and 
4', and, thus, a movement of the cassette holder 6 between the side walls 
2 and 3 in directions along the axis of the pins 11 and 11' is restricted. 
As mentioned above, the cassette holder 6 is movably supported in the 
extending directions of the slots 4, 4', 5 and 5' between the side walls 2 
and 3 by fixing the bushings 11 and 11' on the pins 8 and 8' from outside 
the side walls 2 and 3, respectively. 
Thereafter, a cam slider 12 shown in FIGS. 5 and 6 is assembled from above 
the chassis 1. The cam slider 12 has, as shown in FIG. 5, slots 12a and 
12b, an end of each of the slots 12a and 12b being open. The pins 7 and 8 
are fitted on the corresponding open end of the slots 12a and 12b, and 
then the cam slider 12 is moved in a direction indicated by an arrow A in 
FIG. 5. In this state, bushings 13 are fixed to the cam slider 12 by means 
of screws screwed into threaded holes 12c from directions indicated by 
arrows in FIG. 6. The bushings 13 are fixed by passing through slots 14 
and 15 formed on the side wall 2 shown in FIG. 1 and through slots 14' and 
15' formed on the side wall 3 (not shown). Accordingly, the cam slider 12 
is movable in a horizontal direction within the chassis 1. 
The present invention is not limited to the specifically disclosed 
embodiment, and variations and modifications may be made without departing 
from the scope of the present invention.