GB2110458A

GB2110458A - Tape guide

Info

Publication number: GB2110458A
Application number: GB08228880A
Authority: GB
Inventors: Haruki Ogata
Original assignee: Victor Company of Japan Ltd; Nippon Victor KK
Current assignee: Victor Company of Japan Ltd; Nippon Victor KK
Priority date: 1981-10-03
Filing date: 1982-10-01
Publication date: 1983-06-15
Also published as: KR840001757U; KR880003725Y1; DE3236691A1; FR2514186A1; DE3236691C2; FR2514186B1; JPS5852662U; JPH026557Y2

Abstract

A tape guide comprises a guide roller rotatably fitted over a flanged cylindrical shaft and having a pair of end flanges 40, 41 with conical taper surfaces 44, 45. The guide roller also has a pair of tapered surfaces 42, 43 adjacent to the end flanges, respectively. The conical taper surfaces and the tapered surfaces jointly define a pair of annular grooves of substantially V-shaped cross section. When a tape such as a video magnetic tape is skewed with respect to the longitudinal axis of the tape guide while the tape is travelling around the latter, an edge of the tape is snugly received in one of the annular grooves without the danger of getting wavy or elongated under undue tension. Dimensions, including tape angles are exemplified irregular tensioning due to backlash etc is considered in relation to the tape cassette adapter described w.r.t. Fig. 1 (not shown). <IMAGE>

Description

SPECIFICATION Tape guide The present invention relates to a tape guide for guiding therearound a magnetic tape such as a video magnetic tape.

One known type of tape guide is used as a guide pole or guide roller for guiding a magnetic tape while it is being fed along a tape path. Such a tape guide normally comprises a flanged cylindrical body around which the tape travels in contact therewith. Especially where the tape guide is mounted on a movable lever or otherwise not fixed in position, the tape guide undergoes more or less backlashes or unwanted movements relative to the tape. The tape as guided by the tape guide thus tends to be skewed with respect to the axis of the tape guide, to contact the tape guide unequally, and to be tensioned unevenly at its edge which then becomes wavy or elongated.

When the edge of the tape engages the flange of the tape guide, the tape edge is liable to get folded on itself or otherwise damaged. Such a wavy or damaged tape edge is quite disadvantageous for video magnetic tapes as audio and control signals are recorded on edges thereof The edge of the magnetic tape is more susceptible to damage where the tape is thinner.

It is an object of the present invention to provide a tape guide for guiding a magnetic tape smoothly therearound while the magnetic tape is being fed along without the danger of causing the tape to get wavy, elongated, or otherwise damaged at its edge under undue tension.

Another object of the present invention is to provide a tape guide which is simple in construction and inexpensive to manufacture.

According to the present invention, a tape guide for guiding a tape to travel therearound comprises a flange cylindrical shaft, and a guide roller rotatably fitted over the flanged cylindrical shaft and having a pair of end flanges for guiding the tape to travel around the guide roller transversely between the end flanges. The guide roller has at least one annular groove adjacent to one of the end flanges, whereby an edge of the tape can be received in the annular groove when the tape is skewed with respect an axis of the guide roller.

The present invention will be described in detail by way of illustrative example with reference to the accompanying drawings, in which; Fig. 1 is a plan view of a tape cassette adapter for allowing a small-size tape cassette to be installed in a standard recorder-reproducer; and Fig. 2 is an enlarged longitudinal crosssectional view of a tape guide according to the present invention.

Fig. 1 illustrates a tape cassette adapter 10 in which a small-size tape cassette 11 is placed so as to be usable in a standard recorder-reproducer (not shown). In use, the tape cassette adapter 10 with the tape cassette 11 installed is loaded into the recorder-reproducer for recording information in or reproducing information from the tape cassette 11 which could not otherwise be mounted per se in the standard recorder reproducer.

The tape cassette adapter 10 has a pair of angularly movable levers 12, 1 3 mounted respectively on a pair of shafts 14, 1 5 and supporting on their distal ends a pair of tape guides 1 6, 1 7 constructed in accordance with the present invention. A driver 18 having a driver lever 18a is rotatably mounted on a shaft 9, and a pair of links 20, 21 are pivotably coupled by a pin 22 to the driver 18. The link 20 is pivotably connected to an L-shaped lever 23 mounted on a shaft 24 and coupled pivotably to a link 25, which is pivotably joined to an arm 26 mounted on a roller 27 which is drivingly coupled to the shaft 14 by an endless belt 28. The link 21 is pivotably connected to a lever 29 mounted centrally on a pin 30 for pivotable movement thereabout and pivotably joined to the lever 13.When the driver 18 is angularly moved about the shaft 19 in the direction of the arrow A from the imaginary-line position to the solid-line position, the levers 12, 1 3 are angularly moved in the directions of the arrows B, C, respectively, from the imaginary-like positions to the solid-line positions for thereby pulling out a magnetic tape 33 from the tape cassette so that the magnetic tape 33 can be guided along a predtermined path in the recorder- reproducer for recording and reproducing operation.

Since the tape guides 16, 1 7 are mounted on the movable levers 12, 13, the tape guides 16, 17 are more or less subjected to backlashes or undesirable movements with respect to the tape 33, with the resulting risk of tensioning the tape 33 irregularly in the transverse direction thereof.

To provide against such a difficulty, each of the tape guides 1 6, 1 7 is constructed as shown in Fig.

2 for allowing the tape 33 to contact the tape guide uniformly to thereby avoid damage to the edges of the tape 33.

More specifically, the tape guide 1 6, 1 7 comprises a central cylindrical shaft 36 having an integral end flange 37 and a separate end flange 38 screwed axially into an end of the shaft 36 remote from the integral end flange 37. The tape guide also includes a hollow guide roller 39 rotatably fitted over the central cylindrical shaft 36 between the end flanges 37, 38. The guide roller 39 has a pair of end flanges 40, 41 spaced axially from each other for guiding the tape 33 therebetween while the latter travels around the guide roller 39.The guide roller 39 has a pair of tapered surfaces 42, 43 adjacent to the flanges 40, 41, respectively, the tapered surfaces 42, 43 being inclined progressively toward the central cylindrical shaft 36 and the flanges 40, 41. The flanges 40, 41 have respective opposite conical taper surfaces 44, 45 joined to the tapered surfaces 42, 43, respectively. The tapered surfaces 42, 43 and 44, 45 jointly define a pair of substantially V-shaped annular grooves 46, 47 adjacent to the flanges 40, 41, respectively.

In operation, the magnetic tape 33 travels around the guide roller 39 as it rotates while being guided between the flanges 40, 41 against transverse positional displacement. When the tape guide 16, 1 are inclined with respect to the tape 33 due to a backlash of the movable lever 12, 13, that is, when the tape 33 is skewed relatively to the axis of the guide roller 39 as shown by the dot-and-dash line in Figure 2, one of the edges of the tape 33, namely the upper edge as shown, undergoes an increased tension.

However, the tensioned tape edge is brought snugly into the groove 46 and hence is prevented from being excessively tensioned. As a consequence, the tape edge does not suffer from undue elongation. The tapered surfaces 44, 45 of the flanges 40, 41 are free from sharp edges or interfering surfaces which would otherwise frictionally engage the tape edges and fold or damage them when the tape 33 gets skewed with respect to the guide roller 39.

The tapered surfaces 42, 43 blend smoothly into the remaining circumferential surface of the guide roller 39 to keep the tape 33 in intimate contact with the guide roller 39 at all times against damage.

The angles of inclination of the tapered surfaces 44, 45 may differ from each other to meet a particular tendency for the magnetic tape 33 to incline with respect to the guide roller 39. For example, the-tapered surface 44 may extend at an angle of about 5 degrees with respect to a plane normal to the axis of the guide roller 39, and the tapered surface 45 may extend at an angle of about 30 degrees with respect to the same plane. The circumferential surface of the guide roller 39 except the tapered surfaces 42,43 should have an axial length in the range of from about 50 to 90%, preferably from about 70 to 80%, of the width of the tape 33 to prevent the tape 33 from being subjected to a localized excessive tension.

Although a certain preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.

Claims

1. A tape guide for guiding a tape to travel therearound, comprising: (a) a flanged cylindrical shaft; (b) a guide roller rotatably fitted over said flanged cylindrical shaft and having a pair of end flanges for guiding the tape to travel around said guide roller transversely between said end flanges; and (c) said guide roller having at least one annular groove adjacent to one of said end flanges, whereby an edge of the tape can be received in said annular groove when the tape is skewed with respect to an axis of said guide roller.

2. A tape guide according to Claim 1, wherein said guide roller has an outer circumferential surface and at least one annular tapered surface blended smoothly into said outer circumferential surface and defining said annular groove.

3. A tape guide according to Claim 2, wherein said one of flanges has a conical taper surface, said annular tapered surface and said conical taper surface jointly defining said annular groove.

4. A tape guide according to Claim 3, wherein said annular groove has a substantially V-shaped cross section.

5. A tape guide for guiding a tape to travel therearound, comprising: (a) a flanged cylindrical shaft; (b) a guide roller rotatably fitted over said flanged cylindrical shaft and having an outer circumferential surface, a pair of end flanges for guiding the tape to travel around said outer circumferential surface transversely between said end flanges, and a pair of tapered surfaces adjacent respectively to said end flanges and blending into said outer circumferential surface; and (c) said end flanges and said tapered surfaces jointly defining a pair of substantially V-shaped annular grooves adjacent respectively to said flanges, whereby edges of the tape can be received respectively in said annular grooves when the tape is skewed with respect to an axis of said guide roller.

6. A tape guide according to Claim 5, wherein said end flanges have a pair of conical taper surfaces, said annular grooves being jointly defined by said conical taper surfaces and said annular tapered surfaces.

7. A tape guide according to Claim 6, wherein said conical taper surfaces are inclined at different angles with respect to a plane normal to said axis of said guide roller.

8. A tape guide constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.