JPS61132371A - Lock mechanism - Google Patents

Abstract

PURPOSE:To enable a movable body to be constantly locked at a predetermined position, by providing an unlocking member for pressing an engaging part and moving a lock arm in an unlocking direction. CONSTITUTION:With an arm 7 depressed downward, a pin 11 is separated from a fastening surface 18 of a lock pawl 10, a projected part 21 at the back of the lock arm 19 is depressed downward by a pin 20 until a helical tension spring 22 is moved to the lower side of the center of a support shaft 13, thereby energizing the arm 19 in the unlocking direction, so that the arm 19 is pulled by the spring 22, and is stabilized on making contact with a stopper 26. When the depressing force on the arm 7 is released, the arm 7 is moved upward, the pin 20 pushes a back part 27 to move the arm 19 in a returning direction, and the pin 11 is passed over the pawl 10. After the pin 11 is retracted from the pawl 10, the arm 19 is pressed in the returning direction by the pin 20, and the spring 22 returns the arm 19 into a lockable condition. Accordingly, the movable body can be accurately locked at a fixed position, without any fluctuation of the lock position.

Description

[Detailed Description of the Invention] [Industrial Application Field] For example, thermal printers, discharge breakdown printers, etc., which make hard copies of images from televisions, video tape recorders, etc., output images from personal computers, etc. In a printer suitable for use with printers, it is extremely convenient to have a structure in which the print medium is loaded by opening the arm while the print medium loading section is pulled out from the blink housing. In this case it is necessary to lock the arm in the closed position. The present invention relates to a locking mechanism suitable for locking a reciprocating part such as the opening/closing operation of an arm at the end of its stroke.

[Conventional technology]

Conventionally, in thermal printers and the like, the top cover of the housing can be opened in order to install, inspect, and maintain thermal paper as a printing medium.

When the thermal paper runs out, open the top cover, remove the remaining thermal paper, and set a new roll of thermal paper. In addition, inspection and maintenance of the printing section, etc., is performed by opening the top cover.

However, with this configuration in which the top cover is opened and closed, it is not possible to place anything on top of the printer, and the top of the printer must be left open at all times.

Therefore, this is not preferable from the point of view of effective use of space.

It also cannot be inserted horizontally into a narrow space such as a rack. Furthermore, if the structure is such that the printing of thermal paper is performed from the top of the printer, an operation panel or the like must also be placed on the top of the casing. Then, the printer must be installed at a low location, such as on a desk, so that the operation panel can be easily seen, which limits the installation location.

Therefore, the inventors of the present invention housed a printing section, a printing medium mounting section, a control circuit section for controlling the printing section, etc., and a power supply section in a housing, as shown in FIGS. 5 and 6. In this printer, the printing part and the printing medium mounting part are built into the housing and supported through a pull-out mechanism so that the printing part and the printing medium mounting part can be pulled forward together with respect to the housing. With this proposal, the upper side of the printer can be completely opened, allowing recording media such as thermal paper to be inserted and removed from the front of the printer, and an operation panel can be installed on the front.

FIG. 5 shows a state in which the printing section is drawn into the casing, and FIG. 6 shows a state in which the printing section is pulled out from the casing. Reference numeral 1 denotes a casing of the printer, in which a control circuit section for controlling a printing section, a paper feeding mechanism, etc., and a power supply section are housed. An operation panel 2 is disposed on the front of the housing, and the operation panel 2
, each substitute switch and display means are arranged.

The housing 1 also houses a printing section and a printing medium mounting section. The printing section and the printing medium mounting section are energized at the fifth
As shown in the figure, when the operation panel 2 is laid down horizontally, it is housed in the housing I, but when a print medium is to be attached or removed, it is pulled out forward from the housing I as shown in FIG.

In FIG. 6, reference numeral 3 denotes a drawer frame having a shape almost similar to a drawer of a desk or the like, and is mounted on a guide rail provided in the housing 1 so as to be movable back and forth.

A roll paper 4 of thermal paper serving as a print medium is housed in a print medium mounting portion in the drawer frame 3. Between this roll paper 4 and the front plate 3a of the drawer frame 3,
A platen 5 is provided.

Further, a cover-like arm 7 is attached to the inner part of the drawer frame 3 via a support shaft 6 so as to be openable and closable, and is biased in the opening direction by a torsion coil spring 9. On the lower side of this arm 7, at a position facing the platen 5,
A thermal head 8 is provided. In FIG. 6, this arm 7 is open, but when this arm 7 is pushed down and closed, the heating element portion of the thermal head 8 is pressed against the platen 4 by a pressure means (not shown). However, the thermal paper 4a unwound from the thermal paper roll 4 is led out from between the platen 5 and the thermal head 8 to the front of the casing. Therefore, the heating element of the thermal head 8 comes into pressure contact with the thermal paper 4a on the platen 5. When the drawer frame 3 is pushed into the housing 1 with the arm 7 closed from above the thermal paper 4a, the state shown in FIG. Ru.

Then, the heating element is energized based on the print information and selectively generates heat to heat the thermal paper 4a, thereby performing printing. Note that the heating element of the thermal head 8 and the heat sensitive 'r
It goes without saying that the feeding mechanisms i and 4a, etc., and the control circuit and power supply section in the housing 1 are electrically connected by cables.

By the way, if the arm 7 to which the print head 8 is attached is configured to move relative to the platen 5 in this way, the pressing force of the print head 8 against the platen 5 can be maintained constant at all times and without variation in any printer. It is necessary. To achieve this, it is effective to have a structure in which the arm 7 can be locked in a fixed position with a lock claw 10 as shown in FIG. In this figure, arm 7
A pin 11 is attached to the free end side, and a claw 1 is attached below the core pin 11 to the drawer frame 3 side.
A locking arm 12 having a diameter of 0 is mounted on an axle 13. In this lock arm 12, the claw 10 is connected to the pin 11.
A tension coil spring I4 is attached to the lower end so as to be biased toward the side. The lock arm 12 is normally biased by the coil spring 14 until the lower end of the lock arm 12 abuts against the stopper 15. In this state, arm 7
When it is pushed down and closed, the slope 16 above the pawl 10 at the tip of the lock arm 12 is moved by one pin, and the lock arm 12 rotates to the position shown by the broken line. And pin 11 is claw 1
0, the lock arm 12 is pulled by the coil spring 14 to the position shown by the solid line, and the claw 10 touches the pin 11.
is caught and locked. Since the arm 7 is urged upward by the torsion coil spring 9, the pin 11 is always locked to the locking surface 18 at the lower end of the mold 10, and its position remains constant. As a result, the print head 8 is pressed against the platen 5 with constant pressure by the leaf spring F attached to the arm 7, and the print quality is stabilized.

[Problem that the invention seeks to solve]

However, with this configuration, when the arm 7 is opened and the printing medium is attached or detached, it is necessary to first operate the lock arm 12 and release the lock, and thus an improvement is required in terms of operability. Moreover, he forcibly pushed the claw 10 of the lock arm 12 into the pin 1.
1, the locking surface 18 of the claw 10 and the pin 11 will wear out due to sliding, and during long-term use, the arm 7 will be displaced in the opening direction, causing the print head 8 to press against the platen 5. The pressure also becomes weaker.

The technical problem of the present invention is to solve such problems with conventional locking mechanisms, to make the opening operation of the lock arm simple, and to be able to always lock a movable body such as a cover-shaped arm in a fixed position. be.

[Means for solving problems]

The technical means of the present invention taken to solve this problem is to
In a mechanism that locks with a lock claw at the tip of a lock arm that is pivotally supported on the fixed side, the spring that biases the lock arm in the direction of engaging and locking the lock arm with the object to be engaged is applied in the direction in which the lock arm moves away from the object to be engaged. When the point of action of the spring on the lock arm passes through the dead point connecting the spring and the lock arm support shaft, the force of the spring acts on the lock arm in a direction away from the engaged body. The lock arm should be provided with an engaging part near the spindle on the opposite side of the lock pawl, and the engaging part should be provided on the movable body side at a position where the engaged body has moved slightly from the locked position towards the spindle. and an unlocking member is provided that presses the engagement portion to move the lock arm in the unlocking direction, and is located at a position near the long claw on the opposite side of the locking claw of the lock arm in the unlocked state. the back of the lock arm,
The lock arm is configured to have a return slope on which the lock arm is pressed in the locking direction by the unlocking member when the unlocking member passes and moves in the opening direction of the movable body.

[Effect]

According to this technical means, the lock arm is biased by a spring such as a tension coil spring so that the movable body can be moved to the lock arm side, and the movable body is moved to the lock arm side. When the engaging body passes through the tip of the lock claw of the lock arm, the engaged body is locked by the claw. To release the lock, push the movable body a little further.

Then, the engaged object separates from the locking surface of the lock pawl, and the unlocking member such as the pin on the back side of the lock arm presses the engaging part such as the protrusion on the back side of the lock arm, moving the lock arm in the unlocking direction. Let's move to J. In the process, the point of action of the spring on the lock arm passes through the support shaft of the lock arm, urging the lock arm in the unlocking direction. Next, when the movable body returns, the unlocking member presses the return slope on the back of the lock arm to move the lock arm to the lockable position. In this process, the point of action of the spring on the lock arm passes through the support shaft of the lock arm,
To stabilize a lock arm by biasing it to a lockable state.

〔Example〕

Next, examples will be used to explain how the locking mechanism according to the present invention is actually implemented. FIG. 1 is a side view showing an embodiment of the locking mechanism according to the present invention, and is an example implemented in the printer shown in FIGS. 5 to 7. An arm 7 having a printing head 8 is a movable body, and a drawer frame 3III holding the arm 7 by a support shaft 6 is a fixed part to the movable body. A bottle 11 which is an engaged body is fixed on the arm 7 side which is a movable body, and a lock arm 1
A bottle 20 serving as an unlocking member is fixedly provided at a position near the support shaft 13 on the back of the pin 9 (a position opposite to the claw 10).

On the drawer frame 3 side, the lock arm 19 is attached to the support shaft 1.
3, it is rotatably supported. This lock arm 19
Like the lock arm 12 shown in FIG. 7, it has a claw 10 at its tip for locking the bottle 11.

In addition, in the present invention, a protrusion 21 that is pressed when the bin 20 is lowered is provided at a position on the back of the lock arm 19 near the support shaft 13, and constitutes an engaging portion.

On the other hand, a tension coil spring 22 is used as a spring for biasing the lock arm 19. This tension coil spring 22 has one end attached to the hook 23 of the drawer frame 3, and the other end attached to the protrusion 21 of the lock arm 19.
It is attached to the bin 24 near the. lock arm 1
9 rotates between the position shown by the solid line and the position shown by the chain line. In the intermediate position shown by the broken line, the tension coil spring 22 is exactly at the center position of the support shaft 13, and the lock arm 19 is rotated in either direction. The bin 24 is arranged so as to be at a dead point where it cannot be biased in any direction. Therefore, when the tension coil spring 22 is located closer to the pin 11 than the center of the support shaft 13 as shown by the solid line, the lock arm 19
is biased towards the pin 11 side and can lock the bottle 11.

Conversely, as shown by the chain line, when the opening/link arm 19 is located below the center of the support shaft 13, it is urged in the unlocking direction away from the bottle 11.

The claw of the lock arm 19 ■The back of the lock arm 19 has an inclined part 25
is formed. This inclined portion is for returning the lock arm 19 from the chain line position to the solid line position, and when the bin 20 rises, it is pushed toward the slope gB25t-hin 11 side of the chain line position to return the lock arm 19 to the solid line position. let

Next, the operation of this locking mechanism will be explained. Usually, the tension coil spring 22 is located above the center of the support shaft 13, and the tension coil spring 22 is located above the center of the spindle 13.
It is located in a direction that allows it to be locked. Therefore, by pushing down the arm 7 and causing the bottle 11 to pass through the claw 10, the lock arm 19 is temporarily retreated to the broken line position, and the bottle 11 is moved back to the position shown by the broken line.
1 passes the tip of the claw 10, the locking arm 19 returns to the solid line position, locking the bottle 11 and holding the arm 7 closed. This locking action and effect is
This is no different from the conventional mechanism shown in FIG.

To unlock the arm 7 to release it, it is only necessary to push the arm 7 down somewhat. Then, as shown by the solid line in FIG.
The protrusion 21 on the back of 9 is pushed down. Furthermore, the tension coil spring 22 is pushed down until it passes through the support shaft 13 and moves below the center of the support shaft 13. When the tension coil spring 22 moves below the center of the support shaft 13, the tension coil spring 22 biases the lock arm 19 in the unlocking direction, so the lock arm 19 is moved by the tension coil spring 22 to the position shown by the solid line in FIG. pulled,
He hit the par 26 and stabilized. In this state, the claw 10 is retracted from the bottle 11, so when the downward force on the arm 7 is released, the torsion coil spring 9 allows the arm 7 to rise. When it starts to rise, the bottle 20 on the back
Push the back part 27 of the lock arm 19 to move the four-arm arm 19 little by little in the return direction, and in the meantime, the pin 11 moves upwardly past the pawl 10. After passing, the bottle 20 on the back hits the slope 25 as shown in FIG.
When the lock arm 19 is moved to the position shown by the solid line and further pressed so that the tension coil spring 22 passes through the center of the support shaft 13 and moves above the center of the support shaft 13, the bottle 20 is moved to the upper plate part 28 of the inclined portion 25. pass through the rise.

After the pin 11 of the arm 7 is retracted from the claw 10 in this manner, the lock arm 19 is pressed in the return direction by the pin 20, and the tension coil spring 22 returns the lock arm 19 to a lockable state. As shown in FIG. 2, when the locked arm 7 is pushed down further, the print head 8 is further pressed against the platen 5, but the print head 8 is attached to the arm 7 by a leaf spring 17, and the spring There is no particular problem as it can be evacuated against the pressure.

Although only one set of lock arm 19 and bin 11.20 is shown, if they are arranged on both the left and right sides of arm 7, the lock will be more stable. At this time, each of the bins 11 and 20 can be configured with a rond that spans both left and right ends of the arm 7. Further, the support shaft 13 of the lock arm 19 can also be constructed of a long iron.

〔Effect of the invention〕

As described above, according to the present invention, the lock is released by simply pushing the movable body such as the arm 7 a little further in the same direction as when locking, and moreover, when the movable body returns to its original position, the lock arm The locking arm 19 can also be returned to the lockable position by pressing the inclined portion with the bottle 20, so that the unlocking operation is easier than with conventional locking mechanisms. When the lock arm 19 retracts to the unlocked state, the bin 1
1. In other words, since the engaged object moves away from the locking surface 18 of the lock claw 10 in the vertical direction, the lock position does not fluctuate due to sliding wear between the bottle 11 and the lock claw 10, and the locked position is accurately locked at a constant position. can.

[Brief explanation of drawings]

Fig. 1 is an internal side view showing an embodiment of the locking mechanism according to the present invention, Figs. 2 to 4 are diagrams explaining the operation of the locking mechanism, and Figs. 5 and 6 show a printer that requires the locking mechanism. FIG. 7 is an internal side view showing a locking mechanism in a conventional printer. In the figure, 3 is a drawer frame, 6.13 is a support shaft,
7 is the arm, 9 is the torsion coil spring, IO is the lock claw, 1
1 is a bottle (engaged body), 12.19 is a lock arm, 1
8 is a locking surface, 20 is a bottle (unlock member), 21 is a protrusion (engaging portion), 22 is a tension coil spring, and 25 is a return inclined portion. Patent applicant Fujitsu Ltd. agent Patent attorney Minoru Aoyagi

Claims (1)

[Claims] In a mechanism in which an engaged body provided on a movable body such as an arm is locked by a lock claw at the tip of a lock arm pivotally supported on a fixed side, the lock arm is engaged with the engaged body. When the lock arm moves away from the engaged object, and the point of action of the spring on the lock arm passes through the dead center connecting the spring and the lock arm support shaft, the spring is biased in the locking direction. Arrange the lock arm so that the force of the spring acts on the lock arm in the direction away from the engaged object, and the lock arm should have an engaging part near the spindle on the opposite side of the lock claw, and the lock arm should be movable. An unlocking member is provided on the body side for pressing the engaging portion to move the lock arm in the unlocking direction at a position where the engaged body is slightly moved from the locking position toward the support shaft; Place the back of the lock arm in the unlocked state at a position near the lock claw on the opposite side of the lock claw.
A locking mechanism characterized by having a return slope through which a lock arm is pressed in a locking direction by the unlocking member when the unlocking member passes and moves in the opening direction of the movable body.