JPS6232382Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic sheet for magnetically recording information signals such as still image information as a plurality of annular tracks.

Conventionally, a magnetic sheet on which information signals such as still images are magnetically recorded for convenience in handling and storage is housed in a jacket, and the sheet is attached to a recording and/or reproducing device while being housed in the jacket. . When the magnetic sheet jacket containing this magnetic sheet is attached to the mounting section of a recording device such as an electronic still camera, the magnetic sheet inside the jacket perfectly aligns the center of rotation with the axis of the rotation drive shaft of the rotation drive device. It is necessary that the Therefore, in the conventional magnetic sheet housed in this type of magnetic head jacket, there is a means to maintain the dimensional accuracy of centering by machining the center hole for engaging the drive shaft provided at the rotation center of the magnetic sheet. Alternatively, methods have been proposed in which the rotational load of the magnetic sheet is used to move the magnetic sheet toward the rotation center of the rotational drive shaft. However, with these devices, a gap is created between the rotational center hole of the magnetic sheet and the rotational drive shaft, which causes rocking during rotation, causing rattling, etc., which prevents good magnetic recording. It was difficult to do.

Thereafter, in view of the above-mentioned circumstances, the present applicant developed the first method to prevent the shaking of the magnetic sheet during rotation, thereby preventing the occurrence of wobbling, and realizing stable magnetic recording.
We proposed a magnetic sheet as shown in the figure. This magnetic sheet is rotatably housed in a jacket 1 shown in FIG. 1 for use. In the magnetic sheet body 2 constituting the magnetic sheet, for example, one or more magnetic heads provided in a magnetic recording section in an electronic still camera as a recording device are opened in a part of the jacket 1 and have a window section. This magnetic head magnetically records information signals such as still image information in concentric circles. A center core 5 for receiving and holding a rotational drive shaft 4 of a rotational drive device is attached to the rotational center of the magnetic sheet body 2. The core 5 is formed by molding synthetic resin into a disc shape, a thin cylindrical shape, or the like. A drive shaft insertion insertion hole 6 into which the rotary drive shaft 4 is inserted is formed through the core 5 at approximately the center thereof. A pair of positioning surfaces 7, 7 are formed in a substantially planar V-shape for contacting with the magnetic sheet 2 and aligning the rotation center of the magnetic sheet 2 with the axis of the drive shaft 4, and these positioning surfaces 7, 7 serve as a reference. Thus, the center of rotation of the magnetic sheet with respect to the rotation drive shaft 4 is determined. A pressing portion 8 for elastically pressing the rotary drive shaft 4 against the positioning surfaces 7, 7 is integrally formed in the insertion hole 6 at a position opposite to each of the positioning surfaces 7, 7. has been done. Note that this pressing part 8 is connected to the drive shaft 4
A long hole 9 is provided on the side opposite to the pressing surface 8a with respect to the outer circumferential surface 4a.

By the way, in the above configuration, the elastic portion 8
Since it is integrally molded as a part of the center core 5 made of synthetic resin, the permeability deteriorates due to changes in temperature and over time due to long-term use, and it becomes impossible to support the rotary drive shaft by pressure. There were flaws.

Therefore, the present invention aims to solve the above-mentioned drawbacks and provide a magnetic sheet that always maintains a stable elastic force and can be supported in pressure contact with the drive shaft to stably maintain a centered state during rotation. The purpose is to

That is, in the present invention, a center core for receiving and holding the drive shaft of the magnetic recording device is attached to the rotational center of the magnetic sheet body, and the drive shaft is inserted into the insertion hole of the drive shaft formed in the center core. A positioning surface that aligns the center of rotation of the magnetic sheet body and an elastic tongue that elastically presses the drive shaft against the positioning surface are provided, and the elastic tongue is a metal disposed on one end surface of the center core. The ring is characterized in that a part of the ring is bent to protrude.

Hereinafter, an embodiment of the present invention shown in FIGS. 2 to 4 will be described. In these drawings, the same reference numbers are given to the same members as those in FIG. 1, and detailed description thereof will be omitted.

That is, in the present invention, the center hole 2A of the magnetic sheet body 2 constituting the magnetic sheet according to the present invention
The center core 5 attached to the rotary drive device (not shown) comes into contact with the circumferential surface of the drive shaft 4, which is formed in an eight-shape shape on the inner circumferential wall of the drive shaft insertion insertion hole 6 into which the drive shaft 4 of a rotary drive device (not shown) is inserted. Positioning surface 7, 7
The inner circumferential wall portion of the insertion hole 6 facing the positioning surfaces 7, 7 is formed to have a longer diameter than the shaft diameter of the drive shaft 4.

The outer circumferential shape of the center core 5 is formed into a cylindrical shape with a slightly smaller diameter than the inner diameter of the center hole 2A of the magnetic sheet body 2, and the upper surface 51A is mounted on the outer circumference near the lower end in FIG. 2B. A flange portion 51 that serves as a mounting surface is provided in a protruding manner. Furthermore, an annular recess 52 for attaching a metal ring, which will be described later, is formed on the lower end surface in the axial direction of the core 5, and this concave outer peripheral portion 53 serves as a reference surface for attaching the magnetic recording device to the magnetic recording device. Note that a metal ring 54 made of a magnetically absorbing metal plate is mounted inside the annular recess 52 . This metal ring 54 is attracted by a chucking magnet provided on the side of the magnetic recording device so that the core 5 is firmly connected and held to the magnetic recording device. In the present invention, a tongue piece 55 integrally protruded from, for example, the inner circumferential edge 54A side of the metal ring 54 is bent into an L-shape and stands up, and is inserted into the insertion hole 6 of the center core 5 into each of the positioning surfaces 7. , 7.
That is, the tongue piece 55 comes into pressure contact with the drive shaft 4 and acts to press the positioning surfaces 7, 7 against the drive shaft 4. Therefore, this tongue piece 55 is located on the back of the insertion hole inner wall 6A.
A gap is maintained between the drive shaft 4 and the drive shaft 4, and the drive shaft 4 is arranged and formed so as to be able to come into contact with the drive shaft 4 in a sufficiently resilient manner. As shown in FIG. 2B, this tongue piece 55 is not only formed in an upright shape parallel to the axis of the insertion hole 6, but also has its tip 55A side aligned with the insertion hole 6 as shown in FIG.
If the tongue piece 55 is arranged so as to protrude obliquely toward the center of the insertion hole 6, the pressing force against the drive shaft 4 can be sufficiently increased. Similarly, as shown in FIG. A curved bulge toward the center is effective in improving the pressure contact force and also in smoothly removing and removing the drive shaft 4.

Furthermore, the metal ring 54 is provided with protruding and bent tongue pieces 55 for pressure contact and tongue pieces 56 for engagement, as shown in FIGS. 5 has a protrusion 61 protruding near the upper end of the inner circumference of the insertion hole 6 for inserting the drive shaft to engage the engagement protrusion 55D protruding from the base 55C of the tongue piece 55. If an engagement step 62 is formed on the other end edge and the engagement part 57 formed by bending the tip of the engagement tongue 56 in an L-shape in the outer circumferential direction is engaged, the metal ring 54 is engaged with and attached to the center core 5 without the need for adhesive or the like, and in this case, the above-mentioned engagement tongue piece 56
The tip engaging portion 57 can also serve as a rotation detection portion on the axial end surface of the center core 5 opposite to the side on which the metal ring 54 is disposed. There is an advantage that there is no need to attach it to the core 5.

As mentioned above, in the present invention, a part of the metal ring disposed on one end surface of the center core is bent protrudingly to form an elastic tongue piece that presses against the drive shaft inserted into the drive shaft insertion hole. Because of this, a stable pressure contact force can always be maintained against the drive shaft. Moreover, when the pressure contact force weakens, it is possible to easily adjust the pressure contact force by simply bending the tongue toward the center of the insertion hole.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing a conventional example, FIGS. 2 to 4 are views showing an embodiment of the present invention, and FIG. 2A is an overall view of the magnetic sheet according to the present invention housed in a jacket. FIGS. 2B to 2D are longitudinal cross-sectional views of main parts showing different examples, respectively corresponding to the cross section taken along the line A-A in FIG. 2A, and FIG. 3 is a perspective view of main parts of another embodiment. , FIG. 4 is a longitudinal sectional view taken along line BB in FIG. 3. DESCRIPTION OF SYMBOLS 1... Magnetic sheet jacket, 2... Magnetic sheet, 2A... Center hole, 3... Window, 4... Rotation drive shaft, 4a... Outer peripheral surface of drive shaft, 5... Center core, 6... ...Insertion hole, 7...Positioning surface, 54...
...metal ring, 54A...inner periphery, 55...tongue piece.

Claims (1)

[Scope of utility model registration request] A center core that receives and holds the drive shaft of the magnetic recording device is attached to the rotation center of the magnetic sheet body, and the rotation center of the magnetic sheet body relative to the drive shaft is inserted into the insertion hole for the drive shaft formed in this center core. a positioning surface that aligns the drive shaft with the positioning surface, and an elastic tongue that elastically presses the drive shaft against the positioning surface, and the elastic tongue protrudes a part of a metal ring disposed on one end surface of the center core. A magnetic sheet characterized by being formed by bending.