JPH0720197B2 - Extension device for wire loop of wire loop drive - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rope elongation absorber for a wire rope driving device.

2. Description of the Related Art As an image reading device, a drive device for a mirror traveling body of an electrophotographic copying machine, or a drive device for a carriage of a print head such as a printer, a place where the moving mass can be reduced and the arrangement becomes relatively free. From above, the traveling body is supported so as to be capable of reciprocating along the guide member, and the traveling body is hung over a pulley provided on one or both of the machine frame and the traveling body and a drive pulley rotated by a drive source. A wire drive device is widely used which is reciprocally moved by the drive source via a wire rope (hereinafter, simply referred to as a wire) locked to a machine frame or a traveling body, respectively.

However, in the wire drive device, the wire elongates with time, and if the wire is not absorbed, the tension is reduced and slack is generated, so that the traveling body cannot travel accurately.
In order to absorb the above-mentioned elongation, one end of a single wire under tension or one end of each of a plurality of wire ropes connected in series through the traveling body and under the same tension is locked via a tension spring. , It suffices that the force of the spring urges the loop formed by the wire outward, but by simply applying tension to the wire with the spring, the wire, the spring and the traveling body are formed. The system becomes an oscillating system, and when the traveling body starts up, the tension increases and the spring expands, so that the traveling body cannot be fed in synchronization with the drive pulley, but it also frequently stops suddenly at the desired position like a printer carriage. In such a case, even if the drive source is stopped, the vibration is not attenuated for a certain period of time and the print quality is impaired. Therefore, it is necessary to provide a means for absorbing the time-dependent extension of the wire by a spring and for preventing the wire pulled toward the locking point by the spring or outside the loop from returning.

As a conventionally known wire extension absorbing device, for example, as shown in FIG. 6 of Japanese Patent Publication No. 56-230, a loop of a wire driving device for driving a carriage 102 of a printer which reciprocates along a guide rod 101. A pulley 1 for driving one corner of the wire 103 by driving the wire 103 forming a part of the wire 103 by a drive pulley 105 rotated by a drive motor 104.
06 is pivotally supported on one end of a lever 108 that swings around a fulcrum 107 in the middle portion, and a tension spring 109 is stretched between the other end of the lever 108 and the machine frame so that the pulley 106 is always connected to a wire loop. As shown in FIG. 7, the one-way clutch 110 that urges the lever 108 toward the outside and allows the lever 108 to rotate only in the direction in which the spring 109 contracts as shown by the arrow in the figure, as shown in FIG. The configuration is shown in which is provided between the shaft and the lever.

Further, in Japanese Patent Application Laid-Open No. 56-76753, as shown in FIG. 8, pulleys 114 and 1 around which both ends of a traveling body 111 are attached and loop-shaped wires 113 driven by a drive pulley 112 are wound.
A configuration is shown in which the middle of 15 is hooked on a pulley 116, the pulley 116 is urged to the outside of the loop by a spring 117, and the attachment member 118 of the pulley 116 is supported by a detent member 119 so as not to return. .

In these two examples, inconvenience may occur because the position of the pulley that tensions the wire changes over time. In the example shown in FIG. 6, when the position of the pulley 106 moves, the angle of the wire direction from the drive pulley 105 to the pulley 106 with respect to the axis of the drive pulley 105 is an ideal angle 90.
It deviates from °. If this deviation becomes significant, the rotation of the drive motor 104 cannot be reliably transmitted to the carriage 102. To prevent this, it is necessary to increase the radius of the lever 108, and as shown in FIG. 8, there is a constraint that a pulley for applying a tension must be provided between the two alidler pulleys 114 and 115. .

Also, in the wire extension absorbing device previously filed by the present applicant, the drive pulley or the end pulley having the wire end locked is supported on the shaft fixed to the locking member via the rotary type one-way clutch. At the same time, the pulley is urged via a spring to rotate in the direction in which the wire is pulled. According to this configuration, the position of the pulley that applies tension does not move, but the diameter of the pulley that locks the wire increases, and it is desirable to use a small diameter especially when a drive pulley is used. However, you will be restricted.

SUMMARY OF THE INVENTION In view of the above-described problems of the wire extension absorber of the conventional wire drive device, the present invention makes it possible to reduce the pulley diameter without changing the position of the pulley that applies tension to the wire over time. It is an object of the present invention to provide a wire stretch absorbing device that can be manufactured and is not restricted by a mounting position and a space.

In order to achieve the above object, the present invention provides one end of a single wire under tension for driving a traveling body or one end of each of a plurality of wires connected in series via the traveling body and under the same tension. One or more times in a direction in which rotation is allowed only in the direction in which the pulling force of the wire is increased in the outer ring of the rotary type one-way clutch fitted to the cylindrical shaft fixed to the member to be locked. After winding, lock the above-mentioned locking member via a tension spring, or conversely fix the outer ring of the one-way clutch to the locking member and attach the wire to the shaft fitted inside it with the pulling force. 1 in the direction in which rotation is allowed only in the increasing direction
After being wound more than once, it is engaged with the above-mentioned engaging member via a tension spring.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an example of an image reading apparatus which is one of the devices to which the present invention is applied. In the figure,
The original 2 placed on the original glass 1 is illuminated by a lamp 3, and its reflected light is reflected by the first mirror 4, the second mirror 5, and the third mirror 5.
The light is reflected by the mirror 6 and is projected and imaged on the image sensor 8 by the lens 7. The lamp 3 and the first mirror 4 are integrally carried by a first traveling body (not shown in FIG. 1), move in the direction of arrow A, and the second and third mirrors 5 and 6 are secondly integrated. The carriage is carried by a traveling body (not shown in FIG. 1), synchronously moves in the same direction at half the speed of the first traveling body, and sub-scanning is performed. The main scanning is performed by the self-scanning of the sensor 8, and the original 2 is two-dimensionally scanned by these and converted into an electric signal and output. 3 ', 4', indicated by chain lines in the figure
5'and 6'indicate the positions of the lamp and the mirror when the sub-scan is completed.

As a drive device for moving the first traveling body and the second traveling body in synchronization with each other at a speed of 2: 1, a wire driven by a drive source is fixed to the second traveling body and the second traveling body is used. Widely used are wire drive devices that are wound around a moving pulley that is pivotally supported by and are moved at a speed of 2: 1 in synchronization with the principle of a moving pulley.

FIG. 2 shows an example thereof. The first traveling body 11 is
Guide shaft 9 fixed to the machine frame with brackets 10 at both ends
Is slidably supported by two bearings 12, 13 on the second traveling body 1
The bearing 5 is slidably supported by bearings 16 and 17 fitted to the guide shaft 9 outside the two bearings 12 and 13. The mirrors and lamps carried by these are omitted in FIG. The drive wire 29, which is rotatably driven by a drive motor 26 fixed to the apparatus, has one end of a drive wire 29 wound several times around the pulley 28.
It is fixed to the point 31 on the 15 and the other is also fixed to the point 35 on the second traveling body 15. A movable pulley 1 is provided at both ends of the second traveling body 15.
Wires 20, 8 and 19 of which are pivotally supported and whose both ends are fixed to points 21 and 25 on the machine frame are wound around these movable pulleys, and the wire 20 is the first between the movable pulleys 18 and 19. It is fixed to a point 14 on the carriage 11. When the drive motor 26 rotates the drive pulley 27 in the direction of arrow C with the above configuration, the first traveling body 12 and the second traveling body 15 synchronize in the A direction at a speed of 2: 1 by the principle of the moving pulley. Moving is conventional.

Now, the wire 20 connected in series via the second traveling body 15
According to the present invention, one end of each of the shafts 29 and 29 is provided with a shaft 22, 32 fixed to the machine frame and the second traveling body 15, respectively, as shown in FIG.
After being wound around the rotary type one-way clutches 23 and 33 fitted in the direction 1 or more times in the direction in which rotation is permitted only in the direction in which the pulling force of the wire increases, the machine frame is inserted via the tension springs 24 and 34. And, it is locked at the locking points 25 and 35 on the second traveling body. A rotary type one-way clutch is constructed by providing a plurality of balls held by a cage between a shaft and an outer ring like a ball bearing, but a cam is formed on the inner surface of the outer ring for each ball. In addition, the cage is provided with a spring that acts in the direction of causing a wedge action by pressing the ball between the cam and the outer peripheral surface of the shaft, and when the shaft and the outer ring rotate in a certain direction, the wedge action of the ball occurs. The shaft and outer ring rotate integrally with each other, and when the relative speed of the shaft and outer ring exceeds a certain value in the opposite direction, they are free to rotate and the clutch breaks.This is a compact and reliable one-way clutch. It is capable of acting.

The operation of the above wire extension absorber will be described below.

When the wire is long, the tensile force that acts on the wire is large, or the wire diameter is small, it tends to expand, and the wire expands relatively large at the beginning of use (initial elongation), then stabilizes and takes a long time. , Grows only slightly. As described above, in this device, the wire is wound around the outer surface of the outer ring of the rotary type one-way clutch at least once and then locked at the locking point via the spring. The appropriate diameter is about 10 to 40 times the diameter of the wire.If the outer diameter is large, the wire and the outer circumference of the clutch will slip unless the winding frequency is increased.
It becomes impossible to stretch and absorb. For example, the diameter of the wire is 0.6m
When the shaft diameter is 6 mm and the inner diameter is 6 mm, the outer diameter of the rotary type unidirectional clutch is about 10 to 12 mm, so the diameter ratio is 17
It is convenient because the wire can be wound around the outer circumference of the outer ring. Of course, a grooved pulley may be fitted over this.

The direction of winding the wire around the outer circumference of the rotary type one-way clutches 23 and 33 is set so that the outer ring of the one-way clutch is allowed to rotate only in the direction in which the tensile force of the wire increases. When the wire is extended, the wire is pulled by the tension springs 24 and 34 and moves in the direction indicated by arrow B in the figure together with the outer ring of the one-way clutch. However, even if the wire is pulled in the opposite direction due to the inertia of the running body when the running body is started, or the running body vibrates when stopped, the wire does not return due to the action of the one-way clutches 23, 33. Moves at the same amount in synchronization with the drive pulley at the time of starting, and is prevented from vibrating at the time of stopping.

The method of applying the wire for moving the first traveling body 11 and the second traveling body 15 at the speed ratio of 2: 1 is not limited to the example of FIG. Another example is shown in FIG. The same members as those in FIG. 2 will be described with the same reference numerals. There is only one drive wire 40, one end of which is locked to a point 41 fixed to the machine frame,
After half-circulating the dynamic pulley 42 pivotally supported by the traveling body 15, the driving pulley 46 rotationally driven by the drive motor 45 after engaging with the clamp portion 43 of the first traveling body 11 and further semi-circulating the left turn pulley 44. After a few turns, the right turn pulley 47 is half-turned, the moving pulley 42 is half-turned from the opposite side, and the wire is attached to the rotary one-way clutch 49 fitted to the shaft 48 fixed to the machine frame. Is wound one or more times in a direction in which the rotation is permitted only in the direction in which the pulling force of the machine increases, and is locked to the locking point 51 on the machine frame via the tension spring 50.

Even when the wire 40 is divided into two parts by the first traveling body 11, the one-way clutch and the spring may be provided only at one end as a whole.

Since the driving operation itself of the first and second traveling bodies 11 and 15 of the wire driving device is conventionally known, the description thereof will be omitted. Even in this device, one end of one wire 40 to which tension is applied is wound around the one-way clutch 49 at least once in a direction in which the wire is allowed to rotate only in the direction in which the pulling force of the wire is increased, and then the one-way clutch 49 is attached via a spring. Since it is locked to the frame, it is possible to prevent the spring from extending and delaying the movement of the traveling body at the time of start-up, and the vibration of the traveling body at the time of stopping, as in the above-described embodiment.

In each of the above-mentioned embodiments, as shown in FIG. 4, the wire is wound around the outer ring of the rotary type one-way clutch fitted on the fixed shaft, but the outer diameter of the wire winding portion is set in one direction. If it is necessary to make it smaller than the outer diameter of the clutch,
As shown in the figure, the outer ring of the rotary type one-way clutch 54 is attached to the machine frame 52.
The sleeve 53 fixed to the
55 is fitted, and retainer ring 56 is used to prevent
The wire 57 may be wound around the shaft 55.

The embodiment in which the present invention is applied to the image reading apparatus has been described above. However, the present invention can be applied to a wire extension absorbing device of a device for driving a traveling body by a wire such as an electrophotographic copying machine or a printer. it can.

Effects As described above, according to the present invention, the position of the pulley for imparting tension does not change, and the outer diameter of the member around which the wire is wound can be reduced, so that the arrangement is facilitated and the design is improved. The degree of freedom of is increased.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a schematic configuration of an image reading apparatus to which the present invention is applied, and FIG. 2 is a side view showing an embodiment to which the present invention is applied to an example of a wire driving device for driving a scanning traveling body. FIG. 3 is a side view showing an example of another wire drive device to which the present invention is applied, FIG. 4 is a cross-sectional view showing a main part of the present invention, and FIG. 5 shows a modification thereof. Sectional views and FIGS. 6 to 8 are perspective views or plan views showing a wire driving device provided with a conventional wire extension absorbing device. 9 ... Guide member, 11,15 ... Running body, 18,19,28,42,44,
47 …… Pulley, 20,29,40,57 …… Wire, 22,32,48,55…
… Axis, 23,33,49,54 …… Rotary one-way clutch, 24,34,5
0 …… tension spring, 26,45 …… drive source, 27,46 ……
Drive pulley

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04N 1/107

Claims (2)

[Claims] 1. A traveling body capable of reciprocating along a guide member is spanned between a pulley provided on one or both of a machine frame and the traveling body and a drive pulley rotated by a drive source, and both ends thereof. In the wire rope extension / absorption device of the wire rope drive device that reciprocates by the above-mentioned drive source via the wire ropes locked to the machine frame or the traveling body, respectively, in series through one end of the single wire rope under tension or the traveling body. Connect one end of each of the plurality of connected wire ropes to which the same tension is applied to the outer ring of the rotary type one-way clutch in which the inner ring is fixedly fitted to the cylindrical shaft fixed to the member that locks it. The wire rope is characterized in that the wire rope is wound once or more in a direction in which rotation is allowed only in a direction in which the pulling force increases, and then locked to the above-mentioned locking member via a tension spring. Stretch absorber. 2. A traveling body capable of reciprocating along a guide member is spanned between a pulley provided on one or both of the machine frame and the traveling body and a drive pulley rotated by a drive source, and both ends are extended. In the wire rope extension / absorption device of the wire rope drive device that reciprocates by the above-mentioned drive source via the wire ropes locked to the machine frame or the traveling body, respectively, in series through one end of the single wire rope under tension or the traveling body. A direction in which the pulling force of the wire rope increases on the shaft that is fixedly fitted to the inner ring of the rotary one-way clutch in which the outer ring is fixed to the locking member at one end of each of the plurality of connected wire ropes to which the same tension is applied. An extension absorbing device for a wire rope, characterized in that it is wound on the above-mentioned locking member via a tension spring after being wound one or more times in a direction in which rotation is allowed only in the direction.