JPH03126936A - Reciprocating driving device - Google Patents

Abstract

PURPOSE:To perform reciprocatingly drive without employing a spring clutch and a solenoid by disposing pinion gears that can rotate and revolve and two racks engaging with the pinion gears. CONSTITUTION:The pinion gears 3 and 4 which are supported so as to revolve while rotating and two racks 1 and 2 are disposed. First the pinion gear 3 engages with the advancing rack 1, which is fed in one direction, separates from the end of the advancing rack 1, revolves and butts against the retreating rack 2 on the opposite side. After that, the pinion gear 4 engages with the retreating rack 2, which is fed in the opposite direction, separates from the end of the retreating rack 2, revolves, butts against the advancing rack 1, and reiterates a similar action. Consequently, a spring clutch, a solenoid, etc., are not needed any more, and the device can be reduced in size and weight. Moreover, its manufacturing costs are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reciprocating drive device used, for example, in a movable document table of a copying machine.

(Prior Art) Conventionally, as an example of using a reciprocating drive device, a copying device with a moving document table is known. The document table reciprocating drive of this type of copying device uses a unidirectional rotating motor that also serves as the drive for the copying device main body as the drive source, and a spring clutch that transmits and cuts off the drive forward and backward, and a spring clutch that switches between the two. This was done by a combination of solenoid and gear train.

(Problems to be Solved by the Invention) However, such conventional technology has the following problems.

(1) If the spring clutch itself has a large number of parts and there are variations in precision among the parts, phenomena such as strange noises, slippage, spring breakage, and spinning may occur. Therefore.

Managing the precision of individual parts was difficult.

(2) Spring clutch, solenoid closing volume, and
Due to the large weight, especially in small-sized copying machines, the overall space of the drive device becomes large, which is contrary to the demand for miniaturization of the device.

Furthermore, due to the heavy use of high-precision parts, the device has become expensive.

(3) Also, the solenoid generates a pre-shock when activated. Particularly in copying machines, which are often used in quiet offices, the noise can be audible, and a countermeasure has been desired.

The present invention has been made in order to solve the problems of the prior art described above, and its purpose is to provide a pinion gear that can rotate and revolve around its axis, and two racks that mesh with the pinion gear. It is an object of the present invention to provide a reciprocating drive device that performs reciprocating drive without using a spring clutch or solenoid.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a reciprocating drive device which is provided with a drive means and moves a movable table back and forth repeatedly. a pinion gear that engages with a gear that rotates and is supported so as to be able to revolve while rotating, and the pinion gear and its center of revolution,
Two racks, one for forward movement and one for backward movement, are installed parallel to the moving direction of the moving platform and in the range that the pinion gear collides with when it revolves, and the two racks are arranged behind the respective rear ends. It is characterized in that the pinion gear is fixed to the movable base, leaving a space for at least the pinion gear to revolve and hit the rack on the opposite side.

When the pinion gear and the rack are in mesh, the angle between the rack and a straight line connecting the center of revolution and the center of the pinion gear is defined as A, and the angle between the rack and the pinion gear is on a straight line indicating the meshing pressure angle direction. When the center of revolution is placed at , and the angle between the rack and the straight line connecting the center of revolution and the center of the pinion gear is B, then B<A<
90', the pinion gear reliably hits the rack, enabling stable drive transmission.

Furthermore, if the pinion gear is constructed by fixing two gears with different circumferential speeds in parallel, and one gear meshes with the outward rack and the other gear meshes with the return rack, then This enables reciprocating M movement and shortens the movement time.6 (Function) First, the pinion gear meshes with the forward rack,
The forward roller 7 is sent out in one direction. Then, at tm after the forward rack, the pinion gear separates, revolves, and hits the reverse rack on the opposite side. After that, the pinion gear and the reverse rack engage, sending the reverse rack in the opposite direction. Furthermore, the pinion gear separates from the rear end of the reverse rack, revolves, and hits the forward rack on the opposite side, repeating the same action.

(Example) An example in which a reciprocating drive device according to the present invention is applied to a movable document table of a copying machine will be described below with reference to the drawings.

Here, FIG. 1 shows a state in which 23 racks fixed to a document table serving as a moving table are moving linearly in the forward direction, and FIG. 2 shows a cross section of the racks in an engaged state along line CC. ing. FIG. 3 shows a state in which 23 racks are moving linearly in the backward direction, and a cross section of the engaged state along EEji is shown in FIG. 4.

First, referring to FIGS. 1 and 2, the components of the document table of the copying machine consist of the document table glass 27, the document pressure plates 24 and 29 for pressing the document, and the rack stand 23 that fixes the rack. It is positioned on the side plate of the main body via a rail 32 so as to be capable of reciprocating linear movement.

Two racks, a forward rack 1 and a backward rack 2, are fixed to the rack stand 23 in parallel to the direction of movement of the original table and at least within a range where a pinion gear, which will be described later, abuts against them. A pinion gear that rotates in one direction and is rotatably supported around the shaft 12 is disposed between the two wooden racks. In this embodiment, in order to change the forward and reverse speeds of the document table, the pinion gear is constructed by arranging a forward gear 3 and a reverse gear 4 with different numbers of teeth in parallel. It is rotatably supported.

The pinion gear 3 meshes with the forward rack l, and the pinion gear 4 meshes with the reverse rack 2.

Next, as the pinion gears 3 and 4 rotate.

The configuration for also performing revolution will be explained in detail. The shaft 12, which is the center of revolution of the pinion gears 3 and 4, has a bearing 18
, 20, and is rotatably supported by a side plate 25 and a support plate 22 of the apparatus main body.

This shaft 12 is provided with a rotating metal plate 21 rotatably supported via bearings 17, 19, and the rotating shaft 16 of the pinion gear 3.4 is fixed to this rotating metal plate 21.

By arranging the rotating sheet metal 21 in this manner, the pinion gears 3 and 4 can revolve around the shaft 12. and,
At the rear of the rear end of the forward rack 1, pinion gears 3 and 4 are provided.
A space is provided in which the objects can revolve. For this purpose, the forward rack 1 is made shorter in length than the reverse rack 2 at the rear end. The same applies to the reverse rack 2. (See Figure 3).

Next, a configuration for driving pinion gears 3 and 4 will be described. A gear 5 is rotatably supported on the shaft 12, and a gear 6.7 is fixed thereto. The pinion gear 3 meshes with the gear 5, and the pinion gear 4 meshes with the gear 6. The driving force of the motor 11 as a driving means is transmitted to the gear 5 via the gears 9b and 10, and is transmitted to the gear 6 via the gears 9a and 8.7.
It is now possible to convey the information to Therefore, as the gear 5.6 rotates, the pinion gear 3.4 receives a driving force for rotation. (See Figure 4 f@).

In this embodiment, as is clear from the figure, the gears 5 and 6 are set to receive rotational force in the clockwise direction, and the pinion gears 3 and 4 are set to receive the driving force for rotation in the counterclockwise direction. , receives a moment force in the clockwise direction due to the pressure applied to the meshing tooth surfaces. This moment force becomes a driving force for causing the pinion gears 3 and 4 to revolve. In order to obtain reliable moment force, a friction resistance member 31 is sandwiched between the forward pinion gear 3 and the rotating metal plate 21.

The forward movement of the reciprocating drive device having the above structure will be described with reference to FIGS. 1, 2, and 5. Motor 1
1 is transmitted to the forward pinion gear 3 via the forward gear 9b, gear 10, and gear 5 fixed to the output shaft. The rotation direction at this time is as shown in the figure. The forward pinion gear 3 hits the forward rack 1 due to the moment force of the aforementioned revolution. At this time, the forward rack 1 is in a position where it does not mesh with the reverse pinion gear 4. In this state, the pinion gear 3 meshes with the forward gear 1, and the rack base 23 starts forward linear movement (see Fig. 5(a)).The rack base 23 continues to move forward, and the pinion gear 3 moves forward. When the pinion gear 3.4 reaches the rear end of the forward rack 1 (see FIG. 5(b)), it leaves the forward rack 1 and the pinion gear 3.4 begins to revolve as described above. Then, the revolution continues until the reverse pinion gear 4 abuts against the reverse rack 2 whose tooth surfaces face each other with the center of revolution in between (see FIG. 5(C)), and then enters the later-described backward movement.

Next, the operation when moving backward will be explained with reference to FIGS. 3, 4, and 5. The driving force of the motor 11 is transmitted from the reverse gear 9a fixed to the output shaft via the gear 8 to the gear 7 fixed to the shaft 12, and then via the gear 6 fixed to the shaft 12. The driving force is transmitted to pinion gear 4 for reverse movement. The rotation direction at this time is as shown in the figure.

The subsequent backward movement of the rack stand 23 is the same as the forward movement described above (see FIG. 5(C)). Note that when traveling backward, the forward pinion gear 3 is in a position where it does not mesh with the reverse rack. Then, when the rack base 23 continues to move backward and the pinion gear 4 reaches the rear end of the backward rack 2,
The pinion gear 4 separates from the reverse rack 2 and revolves (see FIG. 5(d)), and the forward pinion gear 3 hits the forward rack and the rear. Thereafter, the rack base repeats forward and backward movements in the same manner.

Here, a preferred relationship between the pinion gears 3, 4 and the rack will be explained. When the pinion gear meshes with the rack, the meshing tooth surface receives the load from the rack. This load acts in the direction of the gear pressure angle α. Therefore, if the angle formed by the rack and the straight line connecting the pinion gear's rotation center and the revolution center is A, then the revolution center is placed on the straight line showing the meshing pressure angle direction of the rack and pinion as shown in Fig. 6. By setting the pinion gear between the angle B when it is placed and 90' as shown in Figure 7, a moment force will be applied to the pinion gear when it bites in the direction of engagement with the rack, so it will not escape when it is engaged with the rack more easily. This means that the driving force can be transmitted reliably without any problems.

Further, gear specifications used in the apparatus of this example are summarized in Table 1 below.

Note that if the rotation speed of the motor 11 is 3 Orpm, the forward rack speed is 20.1 mm/see, and the reverse rack speed is 70.4 mm#ec.

Finally, FIG. 8 will be explained. FIG. 8 shows a state in which the pinion gear 3 is stopped while being engaged with the forward rack 1. If it is necessary to move the document table after it has stopped in this engaged state, simply move the document table manually in the forward direction (in the direction of the arrow), and the pinion gear 3 will move counterclockwise around the shaft 12. In this state, the document table can be freely manually moved in either the forward or backward direction.

Although the embodiment device shown in the figures has been described above, the present invention is not limited to the embodiment. In particular, although the forward and reverse speeds were changed in the above embodiment, the forward and backward speeds were made the same. 0 If forward and backward movement is to be made at a constant speed, it is not necessary to divide it into two stages of pinion gears as described above.
The configuration becomes even simpler because the gear 8 and the gear 7.6 are no longer necessary and the reverse rack 2 only needs to be moved to a position where it meshes with the forward pinion gear 3. Further, by configuring the drive gear 9 of the main motor 11 to also serve as a drive source for paper conveyance on the main body side, an image carrier, etc., it becomes easy to synchronize the moving speed of the document table during forward movement.

In particular, although the reciprocating motion of a document in a copying machine and the like is given as an example, it can also be applied to other reciprocating drive devices such as a scanner in a printer.

(Effects of the Invention) The present invention has the configuration and effects described above, and by disposing a pinion gear that is supported so as to be able to revolve while rotating on its own axis and two racks, it is possible to reciprocate the movable platform. Therefore, unlike conventional devices, spring clutches, solenoids, etc. are not required, and the device can be made smaller and lighter, and the cost can be reduced. Furthermore, since the number of parts is reduced, the effort of managing parts is saved, and since no solenoids are used, it is possible to provide a quiet device.

By installing pinion gears with different circumferential speeds in parallel,
It is possible to change the speed of forward and backward movement, and it is possible to shorten the reciprocating movement time.

In addition, even when stopped, simply by manually moving the moving table in the direction of movement when stopped, the pinion gear separates from the rack, making it possible to move the moving table back and forth, which is especially useful for jam removal when used in copying machines, etc. It's convenient.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of the reciprocating drive device according to the embodiment of the present invention when the rack base is moving forward, and FIG. 2 is a diagram showing the engaged state along the line C-C in FIG. FIG. 3 is a cross-sectional view showing the state when the rack base is moving backward, and FIG. 4 is a cross-sectional view showing the engaged state along line E-E in FIG. 3. Figures 5(a), (b), (c), and (d) are diagrams showing the reciprocating linear movement of the rack base as a series of operations, and Figures 6 to 8 show the positional relationship between the rack and pinion gear. It is a figure for explaining. Explanation of symbols 1... Forward rack 2... Reverse rack 3.4
... Pinion gear (3... Forward pinion gear, 4
... Reverse pinion gear) 5.6 ... Gear that has a drive means and rotates in one direction, 11 ... Drive means (motor) 12 ... Center of revolution 21 ... Rotating sheet metal, 23・
・・Rack stand (moveable stand) Fig.-E

Claims (3)

[Claims] (1) A reciprocating drive device that repeatedly moves a movable table back and forth by disposing a drive means, comprising: a pinion gear that has a drive means and is supported so as to be able to revolve while rotating while meshing with a gear that rotates in one direction; Two racks, one for forward movement and one for backward movement, are provided between the pinion gear and its center of revolution, parallel to the moving direction of the moving platform, and in the range that the pinion gear collides with when it revolves; The reciprocating drive device is characterized in that the racks are fixed to the movable base, leaving at least a space behind each rear end for the pinion gear to revolve and hit the rack on the opposite side. (2) When the pinion gear and the rack are in mesh, the angle between the rack and the straight line connecting the center of revolution and the center of the pinion gear is A, and the straight line indicates the direction of the meshing pressure angle of the rack and pinion gear. When the center of revolution is placed above, and the angle between the rack and the straight line connecting the center of revolution and the center of the pinion gear is B, then B<A<9.
The reciprocating drive device according to claim 1, wherein the angle is 0°. (3) The pinion gear is configured by fixing two gears having different circumferential speeds in parallel, and one gear meshes with the outward rack and the other gear meshes with the return rack. The reciprocating drive device according to (1).