GB2113395A

GB2113395A - Speed monitor for tape recorders

Info

Publication number: GB2113395A
Application number: GB08300452A
Authority: GB
Inventors: Yew Fei Lai
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-01-08
Filing date: 1983-01-07
Publication date: 1983-08-03
Also published as: GB8300452D0

Abstract

A speed monitoring device for a cassette-type tape recorder or player has a casing 1 having the shape and dimensions of a tape cassette. An endless loop of tape 20 (Figure 2, not shown) passes round a rubber sleeve on the hub 16 of a gear wheel and a pair of idler rollers 18 to form a run 20' capable of being engaged by the tape- driving means of the recorder or player. The gear wheel meshes with a smaller gear integral with a disc 8 carrying stroboscopic markings 9, 10 which can be viewed by artificial light through a transparent portion 3 of the casing. <IMAGE>

Description

SPECIFICATION Speed monitoring device for tape recorders and players The present invention relates to devices for monitoring the recording and playback speeds of the tape drive in a cassette-type recorder or player.

Hitherto, tape speed indicating or monitoring devices have employed frequency counters and are therefore relatively bulky, costly and cumbersome to operate and are therefore not suitable in general for home use.

According to the present invention there is provided a speed monitoring device for a cassette-type tape recorder or player comprising a casing shaped to be received in the cassette-receiving space of a tape recorder, a continuous band of tape within the casing guided for movement around a path including a run adjacent openings in the casing to enable the tape to be driven by tape drive means of the recorder or player, a roller arranged to be driven by the band of tape and a rotary element connected to be driven by the roller, the rotary element carrying stroboscopic markings visible from outside the casing.

Simply by viewing the rotary element in artificial light powered by alternating current, the speed of the rotary element and thus of the tape driving mechanism of the recorder or player can be checked.

The frequency of electric lamp powered by standard commercial electrical mains may have a flutuation of about 0.2%. The stroboscopic markings of the rotary element will correspondingly appear to fluctuate in position to some extent but will not seriousiy affect use of the device.

Preferably the device includes speed-increasing means between the roller and the rotary element such that the rotary element is driven in rotation at a higher rotary speed than that of the roller.

Such an arrangement enables the stroboscopic markings to be more widely spaced and therefore more easily visible.

An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, in which Figure 1 is a view from above of a speedmonitoring device for a cassette-type tape recorder or player with a portion of the top wall of the casing broken away, Figure 2 is a view of the device from below with part of the bottom wall broken away, and Figure 3 is a cross section on the line Ill-Ill of Figure 2, on an enlarged scale.

The speed monitoring device shown in the drawings comprises a casing 1, the external dimensions of which are identical to those of the standard form of cassette used with the recorder or player whose tape speed is to be monitored. The top wall 2 of the casing may have the conventional transparent window 3 or, preferably, the entire casing 1 and particulary the top wall 2 may be transparent.

Conveniently, as in the case of normal tape cassettes, the casing 1 is formed of upper and lower haives 2 and 4 which, after assembly, are either welded together or fixed together by screws 5.

Both the top wall 2 and the bottom wall 4 are formed as a pair of openings 6 which are bounded by inturned flanges 7 and openings 25 receive the driving capstan shaft. The holes 6 receive the normal splined driving shafts for the reels of conventional cassettes.

In accordance with the invention, the monitoring cassette shown in the drawings includes a disc 8 carrying two sets of stroboscopic markings 9 and 10 which are appropriately spaced so as to appear stationary when illuminated by a light source powered by frequencies of 60 and 50 Hertz, respectively.

The disc 8 has a hub portion 11 by means of which it is rotatably mounted on the flanges 7 around one of the holes 6. The outer surface of the hub 11 is formed with gear teeth 12 which mesh with teeth 13 on a driving wheel 14 which is rotatably mounted on a pin 15 carried by or integral with the bottom wall 4.

The driving wheel 14 has a hub 16 covered with a rubber sleeve 17.

An endless of tape 20 passes around the hub 16 of the drive wheel 14, in contact with part of the periphery of the sleeve 17, and a pair of idler rollers 18 adjacent the front wall 19 of the casing 1. The run 20 of tape between the two idler rollers 18 passes between openings in the front wall 19 (not shown) and tape supports 21. When the device is inserted into the well of a tape recorder or player and the record or play-back button of the latter is pressed, the tape-driving capstan shaft of the recorder or player enters the opening 25 and the pressure roller of the recorder presses the front run of tape against the capstan shaft thereby achieving a good driving frictional engagement with the tape.In order to ensure that this does not result in breakage of the tape loop, the length of tape forming the loop is chosen to be slightly greater than that required merely to pass around the rollers 16 and 18 and the loop is yieldingly tensioned by elements 22 (which is carried by or integral with bottom wall 4) and 23 which is carried by a springy arm 24.

In a modified embodiment (not shown) which is more suitable for higher tape speeds, the loop or band of tape 18 passes around the hub 11 of the disc 8, the teeth 12 of the hub being replaced by a rubber sleeve similar to the sleeve 17.

1. Aspeed monitoring devicefora cassette-type tape recorder or player, comprising a casing shaped to be received in the cassette-receiving space of a tape recorder, a continuous band of tape within the casing guided for movement around a path including a run adjacent openings in the casing to enable the tape to be driven by tape drive means of the recorder or player, a roller arranged to be driven by the band of tape and a rotary element connected to be driven by the roller, the rotary element carrying stroboscopic markings visible from outside the casing.

2. A device according to claim 1, including speed-increasing means between the roller and the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Speed monitoring device for tape recorders and players The present invention relates to devices for monitoring the recording and playback speeds of the tape drive in a cassette-type recorder or player. Hitherto, tape speed indicating or monitoring devices have employed frequency counters and are therefore relatively bulky, costly and cumbersome to operate and are therefore not suitable in general for home use. According to the present invention there is provided a speed monitoring device for a cassette-type tape recorder or player comprising a casing shaped to be received in the cassette-receiving space of a tape recorder, a continuous band of tape within the casing guided for movement around a path including a run adjacent openings in the casing to enable the tape to be driven by tape drive means of the recorder or player, a roller arranged to be driven by the band of tape and a rotary element connected to be driven by the roller, the rotary element carrying stroboscopic markings visible from outside the casing. Simply by viewing the rotary element in artificial light powered by alternating current, the speed of the rotary element and thus of the tape driving mechanism of the recorder or player can be checked. The frequency of electric lamp powered by standard commercial electrical mains may have a flutuation of about 0.2%. The stroboscopic markings of the rotary element will correspondingly appear to fluctuate in position to some extent but will not seriousiy affect use of the device. Preferably the device includes speed-increasing means between the roller and the rotary element such that the rotary element is driven in rotation at a higher rotary speed than that of the roller. Such an arrangement enables the stroboscopic markings to be more widely spaced and therefore more easily visible. An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, in which Figure 1 is a view from above of a speedmonitoring device for a cassette-type tape recorder or player with a portion of the top wall of the casing broken away, Figure 2 is a view of the device from below with part of the bottom wall broken away, and Figure 3 is a cross section on the line Ill-Ill of Figure 2, on an enlarged scale. The speed monitoring device shown in the drawings comprises a casing 1, the external dimensions of which are identical to those of the standard form of cassette used with the recorder or player whose tape speed is to be monitored. The top wall 2 of the casing may have the conventional transparent window 3 or, preferably, the entire casing 1 and particulary the top wall 2 may be transparent. Conveniently, as in the case of normal tape cassettes, the casing 1 is formed of upper and lower haives 2 and 4 which, after assembly, are either welded together or fixed together by screws 5. Both the top wall 2 and the bottom wall 4 are formed as a pair of openings 6 which are bounded by inturned flanges 7 and openings 25 receive the driving capstan shaft. The holes 6 receive the normal splined driving shafts for the reels of conventional cassettes. In accordance with the invention, the monitoring cassette shown in the drawings includes a disc 8 carrying two sets of stroboscopic markings 9 and 10 which are appropriately spaced so as to appear stationary when illuminated by a light source powered by frequencies of 60 and 50 Hertz, respectively. The disc 8 has a hub portion 11 by means of which it is rotatably mounted on the flanges 7 around one of the holes 6. The outer surface of the hub 11 is formed with gear teeth 12 which mesh with teeth 13 on a driving wheel 14 which is rotatably mounted on a pin 15 carried by or integral with the bottom wall 4. The driving wheel 14 has a hub 16 covered with a rubber sleeve 17. An endless of tape 20 passes around the hub 16 of the drive wheel 14, in contact with part of the periphery of the sleeve 17, and a pair of idler rollers 18 adjacent the front wall 19 of the casing 1. The run 20 of tape between the two idler rollers 18 passes between openings in the front wall 19 (not shown) and tape supports 21. When the device is inserted into the well of a tape recorder or player and the record or play-back button of the latter is pressed, the tape-driving capstan shaft of the recorder or player enters the opening 25 and the pressure roller of the recorder presses the front run of tape against the capstan shaft thereby achieving a good driving frictional engagement with the tape.In order to ensure that this does not result in breakage of the tape loop, the length of tape forming the loop is chosen to be slightly greater than that required merely to pass around the rollers 16 and 18 and the loop is yieldingly tensioned by elements 22 (which is carried by or integral with bottom wall 4) and 23 which is carried by a springy arm 24. In a modified embodiment (not shown) which is more suitable for higher tape speeds, the loop or band of tape 18 passes around the hub 11 of the disc 8, the teeth 12 of the hub being replaced by a rubber sleeve similar to the sleeve 17. CLAIMS

2. A device according to claim 1, including speed-increasing means between the roller and the rotary element such that the rotary element is driven in rotation at a higher rotary speed than that of the roller.

3. A device according to claim 2, wherein the speed increasing means comprises gearing.

4. A device according to any of claims 1 to 3 and including a yieldable tensioning member pressing against a run of the tape.

5. A device according to any of the preceding claims, wherein the rotary element is coaxial with an opening in the casing for receiving a reel drive or tensioning shaft of a recorder or player.

6. A device according to any of the preceding claims wherein the rotary element is a disc.

7. A speed monitoring cassette substantially as described with reference to the drawings.