JPS6348676A - Bearing member, guide post and manufacture thereof - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a bearing member and a guide post for a tape cassette and a method for manufacturing the same, and more particularly to a guide post for a tape cassette that provides an improved tape contact surface. The present invention relates to posts and related manufacturing methods.

[Prior Art] As illustrated in FIG. 1 attached herein, in a conventional videotape cassette 10, a cylindrical tape guide known as a guide post 12 or guide bin 13 is mounted on a cassette base 11. is formed. The guide posts 12 and guide bins 13 serve as tape contact surfaces as the tape (not shown) moves through the tape cassette 10. The quality of the guide post 12 and guide bin 13 greatly influences the quality of tape recording/playback.

For the purpose of describing the present invention, the term "guide post" will be used to refer to both a "guide post" and a "guide bin." This is because the present invention is equally applicable to both.

In some conventional tape cassettes, metal, such as stone-grained stainless steel, is used to make the guide posts. C1] For example, as described in the Umehara patent (U.S. Pat. No. 4,313,551) and illustrated in FIG.
4 is formed by rolling a thin stainless steel plate plated with hard chrome. The surface layer of the chrome is burnished and its ultra-fine tips are rounded off. The guide post 14 includes a V-shaped cutout 16 at its upper and lower ends. During the assembly process, the guide post 14 is fixed at one of its V-shaped cutouts to a triangular projection 18 formed on a projection 20 formed on the base 2' of the tape cassette.

Unfortunately, the metal guide post 14 described in the '551 patent is susceptible to scratching during handling. Therefore, a scratched guide post can damage the tape. To prevent such scratches, complex assembly methods are required, such as using special tools to carefully orient the guide post over the protrusion 20. Also, since stainless steel is rather difficult and expensive to work with, manufacturing guides of such metal is time consuming and expensive. Finally, guide posts that are plated with metal, such as chrome, do not have very good torque values, and this is true of any highly finished guide post surface. As a result, the use of metal guides has not gained full industrial acceptance.

Plastics have also been used to make guide posts. For example, U.S. Pat. No. 4,486°320 (
Sakurai et al.) have announced the following method. It is made by mixing small spheres of engineering plastic containing carbon fibers with esters of higher fatty acids and polyhydric alcohols, and then kneading and molding the mixture using conventional injection molding machines. The overall method is to make a guide post made of plastic.

But plastic guide posts also have their own flaws. In other words, the plastic guide post is
Although known for its excellent smoothness and relative slipperiness, debris tends to bleed into the surface, especially at elevated temperatures, and embedded debris can then slough off its oxide and tape properties. Make a scratch on the back. In addition, plastic guide posts can also result in e+= between the tape and the guide post, which are also inseparable. Such friction can cause the tape to move poorly or can cause dust to collect on the tape. And these things further reduce the recording/playback capability of the tape.

Finally, many efforts have been made to combine the favorable features of plastic and metal guide posts. For example, U.S. Patent No. 4,486,582
No. 3 (published in Shiva) and attached hereto.
As illustrated in the figure, the guide post 24 is provided with a main body 26 made of synthetic resin raw material. A plurality of lowered portions 28 and raised portions 30 are formed on the surface of the main body 25, and a metal layer 32 of, for example, nickel or chromium is formed thereon.

The first step in the method of manufacturing guide post 24 described in the '582 patent is to form a body 26 of synthetic resin such as polyacetal, polyethylene, polyamide, or other crystalline resin. It is to be. Lowered portion 28 and raised portion 30 can be made simultaneously with body 26 or during a second process. A layer of metal can then be formed on the surface of body 26 using a chemical plating process or vacuum deposition.

Although the guide post described in the '582 patent exhibits sufficient lubricity, the method used to make the guide post is complex and relatively expensive.

[Problem 1 to be Solved by the Invention] As can be seen above, conventional guide posts still have certain drawbacks from the point of view of manufacturing and function. That is, as described above, guide posts made only of metal usually require a complicated assembly method, have low manufacturing efficiency, and are high in cost.

On the other hand, even if guide posts made entirely of plastic exhibit good smoothness, sufficient hardness, and adequate lubrication, debris tends to seep into the guide post surface, which can damage the tape. do. As mentioned above, plastic guide posts are also disadvantageously prone to friction. This friction, in turn, causes the tape to become sticky. Finally, attempts to combine the advantageous properties of both plastic and metal in a single guidepost also proved too expensive and complex for efficient mass production and automation.

Therefore, one object of the present invention is to provide excellent surface smoothness,
The objective is to provide a bearing member with characteristics such as lubricity and hardness.

Another object of the invention is to provide a guide post for a tape cassette that has better properties than metal guide posts in terms of lubricity and hardness.

Another object of the present invention is to provide a tape cassette guide post with a low friction and very smooth surface that prevents tape damage and sticking.

A further object of the present invention is to provide a tape cassette guide post that does not require any special installation tools or precise orientation during assembly.

Another object of the present invention is to provide a tape cassette guide post and associated manufacturing method that effectively combines the processing ease of plastic with the perfection of metal.

Finally, one object of the present invention is to
It is an object of the present invention to provide several methods for manufacturing guide posts of tape cassettes, which have the characteristics of increasing manufacturing speed, reducing manufacturing costs, and facilitating automation.

[Means for Solving the Problems] In order to achieve the above-mentioned objects of the present invention and other objects, the present invention provides a bearing member and a guide post for a tape cassette that are improved according to the objects of the present invention, and related thereto. A manufacturing method is provided.

The improved bearing member and guide post are
It includes a filler made of a plurality of individual, highly spherical, rigid members embedded in a plastic substrate. The spherical, rigid member is exposed at its surface to create a hard, low-friction tape contact surface.

The related manufacturing method consists of the following steps. namely, mixing the plastic base material and the filler as described above; forming the mixture into a cylindrical guide post; eroding the surface of the guide post to remove the plastic base material therefrom; This is the process of exposing the filling to the surface. In this way, a contact surface of the bearing member or a tape contact surface of the guide post is formed.

[Embodiments] Preferred embodiments of the present invention will now be described with reference to FIGS. 4 to 7.

Although the preferred embodiment is directed to a guide post for a tape cassette, the invention is also directed not only to the field of tape cassettes, but also to bearing members providing low friction contact surfaces as an application. .

As illustrated in FIGS. 4 and 7, a preferred embodiment of the present invention comprises a generally cylindrical guide post 40 embedded in a plastic substrate 44. , highly spherical, very hard filling 42
Made with. The guide post 40 passes through a cylindrical opening 56 formed along its longitudinal axis to a plastic protrusion 4 formed in the base 48 of the chive cassette 500.
Received by 6.

As shown in FIG. 7, the filler 42 consists of a plurality of individually hard, moldable, preferably spherical members 60 that do not damage the tape. Microscopic spheres of metal such as nickel, glass, ceramic, or other non-magnetic and non-corrosive materials are preferred. Using a metal such as nickel for each member 60 or adding metal fibers to each member 60 makes the guide post 40 conductive and effectively reduces the electrostatic force between the tape and the guide post 40. It is possible to remove such properties.

The plastic base material 44 is preferably made of synthetic resin. This substrate 44 is mixed with filler 42, as explained below. Therefore, the plastic selected for the substrate must have properties that allow the substrate to mix well with the filler 42. Polyacetal, polyethylene and polyamide are good examples.

The guide post according to the present invention has a multi-bedded surface 52 that provides a low friction surface against the tape (not shown) moving through the tape cassette 50. It creates.

An air bearing effect is created on the spherical surface 52,
Its air bearing effect solves the tape adhesion problem that is common with traditional guide posts. On top of that,
The hard surface 52 of the iIiJ prevents debris from becoming embedded therein, thus maintaining the tape's recording/playback performance.

One manufacturing method according to the present invention consists of the following steps.

First, as shown in FIG. 5, a plurality of members 60 are placed in a suitable cylindrical container 62 so as to substantially abut each other. The container 62 includes a rod-shaped insert around which the spherical member 60 is placed. Rod-shaped insert 58
is formed with a cylindrical opening 56 which cooperates with the guide pin 46 during the assembly process, as described above. The plastic substrate 44 is then injected through the injection lower 0 into the container 62 around the plurality of members 60 to form a wet mixture 64 .

As illustrated in FIG.
is forced out of the container 62, for example by a plunger mechanism 66, or by some other known method, to form a continuous, unbroken cylindrical member 57.

Also shown in FIG. 6, a solid cylindrical member 67 is inserted into the cutter 67 at the point indicated by dashed line 72.
8 into individual guide posts 40.

The surface 52 of the guide post 40 is then eroded to remove the plastic substrate 44 therefrom, exposing the spherical member 50, as illustrated in FIG. This eroding process is known to the surface 52 of the guide post 40.
The outer plastic base material 44 is removed by burnishing, tumbling, polishing, framing, etc., or by using a chemical solvent. Burnishing using an abrasive material 74 is illustrated in FIG. 7 and is most effective in terms of manufacturing costs. after that,
If necessary, the guide post 40 can be gardened to remove debris and the guide post 40 is automatically positioned over the protrusion 46, as illustrated in FIG.

Other methods of forming guide post 40 in accordance with the present invention are also clearly easy to implement and are preferred. By way of example, the filler 42 and the plastic substrate 44 can be mixed and pelletized, ie, formed into a rigid cylinder or pellet. The pellets can be placed in conventional injection molding equipment, heated to a liquid form, and injected into a mold to form the cylindrical guide post 40.

As is clear from the above description, the guide post 40 of this embodiment is characterized by a highly spherical and very hard filling in the plastic resin whose surface is eroded, and has excellent smoothness. Demonstrates smoothness and hardness. Similarly, the methods described herein contribute to lowering manufacturing costs and increasing manufacturing speed of improved guide posts, and facilitate automation of tape cassettes.

What has been described above is believed to be the best illustration of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desirable to limit the invention to the precise construction and implementation that have been illustrated and described. For example, the foregoing discussion suggests that the invention is applicable to videotape cassettes. However, the invention can also be used in double reel audio tapes, continuous loop tape cassettes, or in more general bearing applications. It is therefore intended that all suitable modifications and equivalents of this invention be included within the scope of this invention and the appended claims.

[Effects of the Invention] As explained above, according to the bearing member and the manufacturing method thereof of the present invention, the contact surface is made up of a plurality of spherical hard members, so that smoothness, lubricity, and hardness are improved. A bearing member having these characteristics can be provided.

Further, according to the guide post of the present invention, since the contact surface is corroded by a plurality of spherical hard members, the tape cassette has better properties than metal guide posts in terms of lubricity and hardness. We can supply guide posts.

Furthermore, according to the guide post of the present invention, since a plurality of spherical hard members are exposed on the tape contact surface, damage and stickiness of the tape can be prevented, and the tape has a very smooth surface with low friction. Cassette guide posts can be supplied.

According to the guide post of the present invention, since a plurality of spherical nickel members are exposed at each point of tape contact, it is possible to provide a guide post for a tape cassette that effectively combines the ease of processing of plastic with the perfection of metal. .

Still further, the method of manufacturing guide posts of the present invention makes it possible to provide guide posts for tape cassettes that do not require any special fitting tools or precise orientation during assembly.

Furthermore, according to the method for manufacturing a guide post of the present invention,
By injecting and cutting a mixture of a plastic substrate and a plurality of spherical rigid parts into the shape of a cylindrical part and burnishing the surface, the manufacturing speed is increased and the manufacturing cost is reduced over prior art methods. This feature makes automation easy.

[Brief explanation of the drawing]

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to provide a detailed explanation of the invention. . Figure 1 is an exploded perspective view of a conventional tape cassette base, particularly showing the orientation of the guide post and guide pin therein; Figure 2 is a conventional metal guide post engaged with a protrusion formed on the tape cassette base; 3 is an enlarged partial sectional view of a conventional guide post made of plastic and metal, and FIG. 4 is a perspective view of a guide post according to the present invention engaged with a protrusion formed on a tape cassette base. Figure 5 illustrates certain steps according to one embodiment of the method according to the invention, in particular showing the injection of plastic material into the filling to form a mixture; FIG. 6 is a schematic diagram illustrating several other steps according to one method of the invention, in which the mixture of filler and plastic material is ejected while the 11 guide posts FIG. 7 is a schematic diagram of yet another step according to one embodiment of the method of the invention, in particular the erosion of the surface of the cylindrical guide post, for example by polishing. FIG. In the figure, 40... Guide post, 42... Filler, 44...
・Plastic base material, 46...Guide bin, 48...
- Base, 50... Tape cassette, 52... Guide post surface, 56... Opening, 58... Rod-shaped member, 60... Spherical member, 62... Cylindrical container, 64
...Mixture, 66... Plunger, 67... Cylindrical member, 7o... Inlet, 72... Cutting line, 74...
...It is an abrasive material.

Claims (22)

[Claims] (1), (a): A bearing member consisting of a plastic base material; and (b): a filler containing a plurality of spherical hard members in the plastic base material, the filler comprising: A bearing member characterized by being a contact surface of the bearing member. (2) The bearing member according to claim 1, wherein each of the plurality of spherical hard members is non-magnetic and non-corrosive. (3) The bearing member according to claim 2, wherein each of the plurality of spherical hard members is made of nickel. (4) The bearing member according to claim 2, wherein each of the plurality of spherical hard members is made of glass. (5) The bearing member according to claim 1, wherein each of the plurality of spherical hard members is made of ceramic. (6), (a): a step of mixing a plastic base material and a filler; (b): a step of forming the mixture into a cylindrical member; (c): a surface of the cylindrical member A method for manufacturing a bearing member, comprising the steps of: removing the plastic base material therefrom to expose the filling to the surface to form a contact surface of the bearing member. (7) The method for manufacturing a bearing member according to claim 6, wherein the step (c) is performed by burnishing. (8) The method for manufacturing a bearing member according to claim 6, wherein the step (c) is performed by tumbling. (9) The method for manufacturing a bearing member according to claim 6, wherein the step (c) is performed by polishing. (10) The method for manufacturing a bearing member according to claim 6, wherein step (c) is performed by a framing process. (11) A guide post for facilitating the movement of a tape through a tape cassette, the guide post comprising: (a): a plastic base material; (b): a plastic base material; A guide post comprising: a filling made of a plurality of spherical hard members, the filling forming a contact surface with a tape moving through the tape cassette. (12), each of the plurality of spherical hard members is
12. The guide post according to claim 11, which is non-magnetic and non-corrosive. (13) The guide post according to claim 12, wherein each of the plurality of spherical hard members is made of nickel. (14) The guide post according to claim 12, wherein each of the plurality of spherical hard members is made of glass. (15) Claim 1, wherein each of the plurality of spherical hard members is made of ceramic.
Guide post described in Section 1. (16) A guide post for facilitating the movement of the tape through the tape cassette, the guide post having a plastic base material and an exposed surface for movement of the tape through the tape cassette. A guide post comprising a cylindrical member including a plurality of spherical nickel members forming a contact surface with the tape. (17) A method for manufacturing a guide post that facilitates movement of a tape through a tape cassette, the method comprising: (a) mixing a plastic base material and a filler; (b) : forming the mixture into a cylindrical guide post; (c): eroding the surface of the cylindrical guide post to remove the plastic substrate therefrom and expose the filling material; How to make a post. (18) The method for manufacturing a guide post according to claim 17, wherein the step (c) is performed by burnishing. (19) The method for manufacturing a guide post according to claim 17, wherein the step (c) is performed by tumbling. (20) The method for manufacturing a guide post according to claim 17, wherein the step (c) is performed by polishing. (21) The method for manufacturing a guide post according to claim 17, wherein the step (c) is performed by a framing process. (22) A method for manufacturing a guide post that facilitates the movement of a tape through a tape cassette, the method comprising: (a): Injecting a plastic base material into a plurality of spherical rigid members. (b) extruding the wet mixture to form a continuous, unbroken cylindrical member; (c): extruding the wet mixture to form a continuous, unbroken cylindrical member; (d): Burnishing the surface of the cylindrical guide post and removing the plastic base material therefrom;
A method for manufacturing a guide post, comprising the step of exposing the plurality of spherical hard members to the surface.