KR830001572B1 - Automatic stop mechnism - Google Patents

Abstract

An automatic stop or change-over mechanism for tape recorder or other article moving apparatus. After the article has stopped at the sensing location the drive means can be switched off or changed over automatically by movement of a zero member which is part of a differential machanism haveing a unidirectional slip coupling only transmits a force to the zero member after the article has stopped.

Description

Automatic Stopper for Magnetic Tape Recording and Playback Equipment

1 is a perspective view of a stopper according to the present invention.

FIG. 2 is a side view of the main parts for explaining the stopper operation of FIG.

3 is a plan view showing the relative positions of several components of FIG. 2 during operation.

4 is a plan view showing the relative positions of the components of FIG. 3 when the current supplied to the motor is cut off.

5 is a schematic diagram showing the interaction of the catch and cam of the battery during operation.

FIG. 6 is a schematic diagram showing the interaction of the catch and cam of FIG. 5 when the magnetic tape feed is stopped; FIG.

The present invention provides an automatic stopper suitable for a device for starting a control function in response to a local stop of movement of a part along a passage, that is, a magnetic tape device for recording and reproducing signals on a moving magnetic tape. Stopper), in particular, the magnetic tape can be transferred at a precise speed and rotated around the first rotational axis, and the second rotational axis parallel to the first rotational axis in cooperation with the capstan and capstan driving the magnetic tape A press recorder which can rotate about its center, a device for driving a capstan, and a tape recorder having a stopper that automatically stops the operation of the magnetic tape when the tape is at least locally stopped after being operated.

The stopper of the present invention includes the following. In other words,

(a) A first rotating part that rotates during operation of the device and continues to rotate for the time necessary to operate the controller after at least a part such as a tape is stopped or locally stopped.

(b) a second rotating part which makes a rotational motion only during the normal transfer of a part such as a tape during operation of the device and the stop constitutes a signal for a control function that causes the part to stop locally.

(c) slip coupling, first and second coupling parts capable of rotating relative to one another and rotating at a feed rate given by the first and second rotating elements, and operating in the first and second movement directions Including zero elements which can be biased in only one direction, these directions of movement depend on the difference in the rotational speeds of the rotational movements (sliding) between the first and second coupling portions, and the respective coupling portions are accordingly A differential in which the zero element is continuously driven in the first direction while the zero element is loaded to transport the part and the zero element is driven in the second direction while the part is locally stopped.

(d) a stopping device for limiting the operation of the zero element in the first direction of movement, and

(e) a control device such as a switching device coupled by the zero element to stop the device from driving after the zero element operates in the second direction of motion. Particularly in the case of magnetic tape cassette devices, when the magnetic tape reached the end, a machine that automatically stopped or turned off the device appeared to interest consumers. In a cassette device suitable for reproducing a cassette in both directions, the drive device is automatically converted after stopping, so that the program in the cassette can be automatically reproduced continuously. Devices that are not suitable for automatically changing the direction of operation require automatic stops to prevent unnecessary wear and tear on the magnetic tape and to prevent battery depletion in the case of battery power supplies.

In the known automatic stopper of the type described above, the first rotating element which rotates during operation and which continues to rotate even after the tape feed is stopped locally is generally composed of a spindle such as a capstan driven directly by a drive motor. It is. The second rotating element, which only rotates during tape transfer and which does not rotate constitutes a signal that the tape has been locally stopped, is generally composed of a rail disc or a pressing roller.

When the switching device responds to the stop of rotation of the real disk, this does not mean that the magnetic tape is stopped at the same time in different parts of the device. For example, the stoppage of the turntable may be the result of jumping of the winding day. In such a case, when the magnetic tape is continuously conveyed at the position of the capstan, a loop may be formed in the magnetic tape in the cassette, which may damage the magnetic tape and the cassette.

When the roller speed is sensed and the switching device responds to the stop of the magnetic tape at the position of the capstan, the pressure roller must have a width no greater than or less than the width of the magnetic tape. Otherwise, the pressing roller is driven by the capstan even after the magnetic tape is stopped.

A stopper of the first type is known from German Patent No. 1,286,773. In this known stopper, two central gear wheels of the spur gear device are journaled on the spindle. The zero element consists of a lever pivotally pivoted to one end of the same spindle, the free end of which carries two flat blades which engage the respective center gears. One of the two center gear wheels is driven by a capstan through the middle gear wheel, the other center gear is driven by a rail disc and the rail disco is in turn driven by a drive motor through frictional coupling. The center gear spindle is mounted on a pivotable lever. The feed ratio of the deflection days is selected such that the center gear wheel is driven so that the zero member pushes the stop in the first moving direction even at the minimum speed of the reel disk, which is achieved by sliding of the frictional engagement. When the magnetic tape is completely released and the speed of the reel disk is zero, the zero element is moved in the second operation direction and the contact is opened, so that the current supplied to the drive motor is cut off.

A stopper of the second type is known from German Publication No. 2,332,475. In such a stopper, the first engagement portion consists of a spindle parallel to the capstan and the spindle is elastically depressed by a pressure roller. At this time, the press roller acts as the second engaging portion, and the sliding between the engaging portions occurs around the first engaging portion and around the pressing roller. The first engagement portion is a journaled zero member which is a U-shaped bracket pivoted near the end of the limbs about an axis in line with the rotational axis of the pressing roller.

Above the capstan is a gear pinion which drives the gear wheel mounted on the first engagement portion with a 1: 1 transmission ratio through an idler wheel. The diameter of the first engagement portion is selected such that the first engagement portion has a peripheral speed slightly slower than the peripheral speed of the pressing roller during the conveyance of the tape. The sliding between these two elements generates a frictional force to press the L-shaped bracket or zero element toward the stop.

As soon as the magnetic tape stops, the pressure roller stops. However, since the capstan continues to rotate, the first coupling portion also rotates. As a result, the spindle makes a rolling motion around the pressing roller, so that the zero element moves in the second direction and moves the catch so that it is within the range of the cam mounted on the flywheel coupled to the capstan. Since the cam exerts a crash force on the catch, the latching slip in the tape recorder controller is not latched and the drive motor is shut off.

In this stopper, the zero element presses on the first stop during the conveyance of the tape by the frictional force of the sliding engagement. In practice, the frictional force between two parts that can move relative to each other is not constant and changes. Due to the mutual coupling of the elements of the differential and drive motors, the frictional change causes a speed change, which is eventually transmitted to the magnetic tape. This increases the undesirable change in the frequency of the reproduced or recorded signal. The force that causes the zero element to move in the second direction at the end of the transfer of the magnetic tape is determined by the friction in the friction bond. This force is always small because small frictional forces are desirable while the magnetic tape is being transported to prevent unnecessary changes in frictional forces of unacceptable magnitude and to prevent unnecessary loss of energy. The force useful for turning off or stopping the device is eventually small.

It is an object of the present invention to create a non-distributing frictional force, such as a force that affects the uniform drive of a magnetic tape during normal transfer, and a relatively large force to act as a blocking or other control function after the tape or other part is stopped. It is to provide automatic stop.

According to the invention, the sliding engagement is a unidirectional engagement in which the slip between the first and second engagement portions is in only one direction. The zero element is moved in the second direction of operation when the unidirectional coupling prevents the slip between the first and second coupling portions from going in the opposite direction to the one direction described above. The unidirectional coupling can be easily designed so that the frictional force is not generated when the relative movement of the coupling part is in only one direction (separated from the necessary parasitic friction force), and is completely blocked when it is in the other direction of motion.

For tape recorders, it is important not to use unidirectional coupling, which creates undesirable rattling and squeaking noises. In this respect a very preferred embodiment of the invention the unidirectional coupling has a blocking element comprising a catch movably journaled with respect to one of the couplings, the other coupling having at least one cam which interacts with the catch. Equipped with. Since the speed of the cam associated with the moveable journaled catch is very slow while the magnetic tape is being transferred, these two elements move very slowly in relation to each other, resulting in very low noise. In another preferred embodiment, the first and second engagement portions are coaxial and the cam is generally disposed along the axis, and the catch mounted above the second engagement portion has a concave side formed as part of the cylinder surface. That is, the catch is eccentrically journaled to the first engagement portion so that it can pivot about a bearing axis parallel to the axis of the virtual cylinder passing through the center of mass of the catch. The eccentric journal is positioned so that the catch rotates around the cam, but is freely pivoted in response to the engagement between the cam and the catch.

In order to slide in one direction of relative movement between the engaging portions, the cam has a helical cam side that blocks the oscillating motion about the eccentric journal axis while contacting the concave side of the catch while the magnetic tape is being transferred. The outer end of the helical cam surface prevents slipping between the two engaging portions since the stop surface extending inwardly of the cam cooperates with the stop of the catch while the magnetic tape is stopped. By journaling the catch at the center of mass, the catch is always balanced, not pivoted around the journal, and does not collide with other elements under the influence of weight. Therefore, undesirable noise is minimized. As a result, this embodiment is well suited for use in portable magnetic tape devices such as, for example, portable cassette recorders.

In a second form of the above-mentioned stopper known from German Laid-open Publication No. 2,332,475, the first engagement portion is pressed against the pressing roller by a spring. As a result, the pressure roller bearing and the bearing of the first coupling portion are subjected to a load, which may cause an undesirable loss of friction as well as fluctuation of the friction force. In another preferred embodiment of the present invention, the pressure roller is coupled to the differential via gear transmission. By using gear transfer instead of friction transfer, the pressure acting on the bearing arrangement of the first engagement portion and the pressing roller can be significantly reduced.

According to another embodiment of the present invention, the second coupling portion of the unidirectional coupling is capable of rotating around a third rotational axis parallel to the rotational axis of the pressing roller and coupled to the second gear wheel connected to the roller tightly. Contains gear wheels. The first coupling portion of the unidirectional coupling includes a fourth gear wheel journaled to the second coupling portion to rotate about the third rotational axis. The zero element is a lever that can be pivoted around a fourth rotational axis which is kept at a constant distance in parallel from the third rotational axis of the second coupling portion. The fifth and sixth gear wheels on the lever may be coaxially connected to each other and rotate about a fifth rotational axis parallel to the fourth rotational axis.

At least during operation, the fifth gear is still associated with the fourth gear and the sixth gear is combined with the first.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The stopper shown in the figure is such that the movement relative to the capstan 1 and the pressing roller 2 changes after the transfer of the magnetic tape 3 is stopped. The capstan 1 is connected to the flywheel 5 which can rotate about the rotation axis 4 and is driven through the belt 6 by a drive motor (not shown). The capstan rotates in the direction of arrow 7 during operation and continues to rotate for the time necessary for the stopper to operate even after the magnetic tape has stopped at the capstan's position. The pressing roller 2 may rotate about the second rotation shaft 8 parallel to the first rotation shaft 4 of the capstan and rotate in the 9 direction. The pressing roller 2 presses the magnetic tape 3 by the pressing spring 11 which presses the lever 12 in the 13 direction. The pressing roller lever 12 can pivot about pivot axis 14 parallel to the axis 4 of rotation of the capstan. The height of the pressing roller 2 is equal to the width of the magnetic tape 3. At this time, according to the conventional practice, the pressing roller is not driven by the motor but is rotated by the tape movement. When the magnetic tape 3 stops, the pressure roller 2 also stops.

After all, the press roller is a part of the stop roller which constitutes a signal for a stopper in which the transfer of the magnetic tape is locally stopped.

Capstan 1 and press roller 2 are connected to each other via a differential indicated by reference numeral 15. The differential 15 includes a sliding coupling 16, a zero element 17 and first and second coupling portions 18 and 19 which rotate about each other about a common axis. The first engaging portion 18 is driven to the capstan 1 through gear transmission at the traveling speed selected in the direction of arrow 20. The second engaging portion 19 is driven by the pressing roller through the gear transmission at a normal speed which is faster than the traveling speed in the direction of arrow 21.

As described below, the zero element 17 can be moved by a limited distance in one of two directions, but the driving force in the direction I is received by pressing the stator 23 by the tension spring 22 during the transfer of the magnetic tape 3. When the tape stops, the zero element is moved in the moving direction II such that the switching device 24 is driven. The device incorporates a switching spring 26 and a metal switching plate 25 which contact each other and close the electrical circuit during operation. If the switch between the two elements is interrupted by pivoting the switching lever 27 around pin 28 on the switching plate 25, the capstan 1 motor will not be driven.

The sliding coupling 16 is a unidirectional coupling that slides in only one direction between the first and second coupling portions 18 and 19. The engagement 16 comprises a blocking element 29 formed as a catch eccentrically journaled with respect to the first engagement portion 18 because the catch is formed on the second engagement portion 19 and rotates about the cam 30 which will be described in detail below.

The first gear wheel 31 is secured on capstan 4 and the second gear wheel 32 is similarly secured on pressure roller 2 to drive the differential 15. The second coupling part 19 can rotate about a third rotational shaft 34 which is maintained at a constant distance in parallel from the rotational shaft 8 of the pressing roller 2, and has a third gear wheel 33 which is continuously engaged with the second gear wheel 32. . The fourth gear wheel 35 is journaled on the second coupling part 19 and can rotate about the third rotational axis 34 and serves as the first coupling part.

The zero element 17 is formed as a lever pivoted to limit the angular motion about the fourth rotational axis 36 which is kept constant in parallel from the third rotational axis 34 of the second coupling portion 19. Fifth and sixth gear wheels 37 and 38 above lever 17 are journaled on pin 44, respectively, which gears are coaxially tight to each other about a fifth axis of rotation 39 which is held at a constant distance in parallel from fourth axis of rotation 36. Connected. At least during operation, the fifth gear word 37 continuously engages with the fourth gear word 35 and the sixth gear word 38 continuously engages with the first gear word 31.

In fact, all the elements of the stopper are preferably made of plastic. The gear wheel 32 is molded integrally with a plastic hub and a plastic bearing pin (not shown), and forms a roller 2 by fitting a rubber ring to the hub. The second engagement portion 19 is integrally molded and includes a gearwheel 33, a spindle 40, a flange 41 and a cam 30.

The gearwheel 35 with hub 43 is also made of plastic and journaled on spindle 40. Plastic catch 29 is molded with bearing pin 42 and journaled in hub 43. The upper end of spindle 40 is journaled in lever 12. Its lower end may be journaled within a portion of the head slide (not shown) in which the magnetic head of the magnetic tape device is mounted and lever 12 is journaled. Since the pressure roller lever 12 must be able to perform a small pivot movement of about 1 mm in relation to the headslide, the lower end of spindle 40 should be journaled to be slightly pivoted. In practice this is not a problem.

The zero member is pivotably mounted on pin 52 which is firmly connected to the stop of the tape recorder.

The zero member is preferably formed of another plastic mold and interoperates with the protruding pin 44, in which the plastic gear wheels 37 and 38 are integrated into one another, the pin 45 acting on the tension spring 22, and the cam follower 47 on the switching lever 27. It is formed by a lever having a protruding cam 46.

As shown in FIGS. 5 and 6, the catch 29 has a concave cylindrical side 48 in the form of a portion of the virtual cylinder surface. The catch is eccentrically journaled in hub 35 of the first coupling portion 18 so as to be able to rotate about the pin 42 on the axis parallel to the axis of the cylindrical surface and passing through the center of mass Z of the catch. The cam 30 is directed outwardly in contact with the concave side 48 of the catch 29 during the normal transfer of the magnetic tape 3 because the catch rotates about the cam at a traveling speed slower than the normal speed of the cam, as described in detail below. It has a spiral blocked camshaft 49. This interaction transfers the oscillation movement around the journal on catch 29.

The cam 30 has an annular stop face 50 facing the back when the cam rotates. This stop surface extends inward from the outermost part of the helical surface, engaging the pointed stop 51 at the outer end of the crescent catch 29 when the magnetic tape stops. As a result, when the tape is stopped, slippage between the two engagement portions 18 and 19 is prevented.

The operation of the stop is as follows.

[A. Transfer of magnetic tape]

Capstan 1 is driven by a motor through belt 6. The magnetic tape 3 is normally conveyed by pressing the capstan by the pressing roller 2 which is affected by the pressing spring 11. The differential gear transmission is selected so that the steady speed of rotation 21 of cam 30 is slightly faster than the speed of rotation 22 of catch 29 about the cam. As is clearly shown in FIG. 5, it appears that the outer curved cam side 49 of the cam 30 does not touch the catch 29 completely for some time but slides slowly for another time to interact with the concave side 48 of the catch 29.

As a result, catch 29 performs a slow oscillating pivot, for example, oscillates every 30 seconds. Since the frictional force appearing between the first and second engaging portions 18 and 19 is very small, no force is hardly applied around the gear wheel 37. Tension spring 22 can press lever 17 against stator 23. There is a slight gap between the cams 46 and 47 and the switching spring 26 comes into contact with the switching plate 26. The switching spring 26 is magnetically elastic and is mounted in the opening 54 around the pin 53 above the fixing part of the frame of the magnetic tape device in such a way that the spring is always loaded in the direction of the switching plate 25.

[B. Magnetic tape stops]

When the magnetic tape stops, the pressure roller stops 2 degrees. This seems to be that after the second engagement 19 is no longer driven, the cam 30 is also stopped. However, rotation 22 of catch 29 around cam 30 continues. After a while the catch 29 is in a position relative to the cam 30 as shown in FIG. 6 and the stop 51 of the catch engages the fixing surface 50 of the cam. This prevents the gearwheel 35 from rotating any further. Since the gear wheel 37 is continuously driven and engaged with the gear wheel 35, the gear wheel 37 makes a rolling motion around the gear wheel 35. Although this rolling movement is taken around the axis of rotation 36 of the zero member 17, the teeth of the gear wheels 35 and 37 are kept in engagement with each other due to the limited movement of the zero member 17. Because of the force exerted around the gearwheel 37, the lever 17 is pivoted in the II direction. As a result, the cam 46 comes into contact with the cam 47 of the switching lever 27, so that the switching lever 27 is pivoted in the direction 55 as shown in FIG. The switching spring 26 is depressed from the switching plate 25 so that the current supplied to the drive motor is interrupted. As a result, the capstan is also stopped.

In the preferred embodiment shown, the force generated by the gearwheel 37 above the wheel 35, as can be seen in FIG. 1, generates a torque on the lever roller 12 which is against, and against, the force generated by the spring 11. The roller pressure exerted on the tape is reduced. Local wear due to friction of the capstan at one point of the tape can be eliminated because the torque between the roller and the capstan is reduced as long as sufficient torque is delivered to the second engagement portion by the zero member and the press roller lever is pivoted. .

It is also possible to operate the stop catches in order to strip the latching slides with the cam 46 or other parts which are properly connected to the lever 17 in the same manner as described in German Publication No. 2,332,475. Therefore, the magnetic tape device can be switched off and the headslide can be recovered at the same time. In this case, the pressing operation button is reset. Instead of switching off the drive motor, since the converter can be selectively operated, the rotation direction of the capstan 1 is changed and the transfer of the magnetic tape 3 becomes opposite to the transfer direction 10 shown in FIG. Of course, other switching or control actions can also be started.

Claims (1)

A stopper for a device having a device for driving a part along a passage, the stopper comprising: a differential comprising a sliding coupling, a first coupling portion, a second coupling portion, and a zero member; and an apparatus for driving the component. A device for rotating the first coupling, irrespective of whether the part stops locally while the device having the device is in operation, a device for rotating the second coupling in response to the local movement of the component, the first and the second coupling An apparatus for connecting the zero member to pivot the zero member in the first and second directions in response to a relative difference in the negative rotational speed, and an apparatus for performing a control function in response to the zero member moving in the second direction It includes, and the interconnection between the first and second coupling parts such that the sliding coupling proceeds only one way of sliding between the first and second coupling parts and moving parts Block charm when the first and the second engagement portion to prevent the relative speed to zero while the member continues to rotate a first bond orders the automatic stopper for a magnetic tape recording and reproducing apparatus, comprising a step of moving in two directions.

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