JPH0457458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for positioning a workpiece in an automatic assembly line, such as a chassis for equipment.

In the past, it was common for equipment chassis to be assembled manually, but this resulted in uneven quality and was difficult to mass produce efficiently, so in recent years automatic assembly using machines has become more popular. It is being said.

However, when automatically assembling equipment chassis, etc., the machine usually only performs predetermined operations based on a predetermined sequence, so when high-level alignment is required, such as in mating work, components such as equipment chassis etc. It is necessary to place a workpiece in a predetermined position.

The following is an example of how to assemble a copying machine chassis.
The necessity of positioning the above-mentioned workpiece will be mentioned below.

As shown in FIG. 1, from among the front side plate 3 and rear side plate 3' (a, b in the first figure), which are a type of workpieces stacked with the cushioning material 5 in between, the front side plate 3 or the rear side plate is alternately stacked. 3' has been removed and placed in position, the pins 6 to 9 are installed (FIG. 1 c and d). After this, the front side plate 3 and the rear side plate 3' are separately subjected to a process similar to the above process,
The handle rubber 10, the base rubber 11, and the adjustment bolt 12 are attached (e, f, g in the first figure), and the chassis 1 is screwed to the substrate 2, which is a kind of workpiece (h in the first figure), and after being inverted. The assembly is completed (i, j shown in the first diagram).

FIG. 2 shows an example of an automatic assembly line that assembles the chassis 1 of a copying machine through the above steps.
The front side plates 3 and rear side plates 3', which are placed alternately on pallets attached to the conveyor 13, are transferred to the reversing machine 17 after the pins 6 and 7 are attached by the first parts attaching machine 15 (step c in the first figure). , the pins 8 and 9 are attached by the second component attaching machine 16 (step d in the first diagram), and then conveyed to a predetermined position, and then conveyed by the third work loader 62 . On the other hand, the board 2 placed on the pallet provided on the second conveyor 14 is attached with the handle rubber 10, the base rubber 11, and the adjustment bolt 12 by the third component attaching machine 18 (steps f and g shown in the first figure). )
It is transported to a predetermined position and transferred to the third work loader 6.
The chassis 1 is completed by being transported to the assembly device 19 at step 2 and combined with the front side plate 3 and rear side plate 3' conveyed by the third work loader 62.

However, the first to third component mounting machines 15, 1
6 and 18 perform predetermined operations, so in order to automatically assemble the chassis without any inconvenience, the front plate side 3, the rear side plate 3', and the base plate 2 should be
Accurately position the pieces in the predetermined positions and place them one by one.
It is necessary to place it on the second conveyor 13 or the second conveyor 14.

However, the front plate 3, which is an example of the work,
The rear plate 3' and the base plate 2 are placed in exactly the predetermined position (second position).
For workpieces that are not loaded in the directions of arrows p, q, and r in the figure, and that have an asymmetrical shape in the horizontal or vertical directions (hereinafter referred to as asymmetrical workpieces), for example, 180 degrees when viewed in plan from a predetermined position. Some workpieces are placed in a rotating state.

In such a case, it is necessary to rotate the workpiece 180 degrees, position it at a predetermined position, and then place it on the first or second conveyor 13 or 14.

Conventionally, the positioning of the asymmetrically shaped workpiece has been inefficient because the shape of the workpiece has been determined by visual measurement and the workpiece has been manually positioned at a predetermined position.

When an asymmetrical workpiece is placed on a positioning table, the present invention determines whether or not it has rotated by a certain angle from a predetermined position when viewed on a plane, and automatically determines whether or not it has rotated by a certain angle from a predetermined position. The device rotates a workpiece by a certain angle and positions it at a regular position, and its gist is that the device is for positioning an asymmetrical workpiece at a predetermined position, and includes: a turntable on which the workpiece is placed; A positioning member that is individually driven to move from the X and Y directions to a predetermined reference position set in advance with respect to the workpiece on the turntable in a plan view; A presser member is moved and driven individually with an urging force smaller than the positioning member and clamps the workpiece with each positioning member, and the positioning member and the presser clamp the workpiece from the X and Y directions, thereby positioning the workpiece. a sensor for detecting an asymmetrical part of the workpiece in a state where the workpiece is rotated; a driving means for rotating the turntable by a predetermined angle in response to a signal from the sensor; The present invention provides a workpiece positioning device comprising positioning means for moving the positioning member and the holding member relative to the workpiece and repositioning the workpiece.

Next, a workpiece positioning device according to an embodiment of the present invention will be explained with reference to the drawings from FIG. 3 onwards to provide an understanding of the present invention.

Here, FIG. 3 is a plan view of a workpiece positioning device according to an embodiment of the present invention, FIG. 4 is a side view of the same, FIG. 5 is an enlarged view of the part viewed from arrow A in FIG. 4, and FIG. FIG. 7 is a partially enlarged view of the portion viewed from arrow B shown in FIG. 3 in a pinched state, and FIG. 7 is a sectional view taken along line CC in FIG. 3.

As shown in FIG. 3, a turntable 25, which is a type of positioning table for the workpiece 4, is surrounded by a pedestal 27 fixed on the table 20 (as shown in the fourth figure).
The turntable 25 is disposed on the upper part of the table 20, which is a stand for the turntable 25, and is supported by a freebear 26 that has an attached ball that rolls in a free direction. The turntable 25 is driven by a vertical shaft _25a fixed to the lower surface of the center thereof.
It is connected to a rotor cylinder 28 that rotates 180 degrees (see Figure 7).

Further, on the surface of the table 20, there are guides 22 and 23 on which positioning members 30 and 47 for positioning the workpiece 4 slide, respectively, and guides 22 and 23 on which positioning members 30 and 47 for positioning the workpiece 4 slide, respectively.
Guides 21 and 24, on which holding portions 29 and 48 that face each other with the workpiece 4 in between, slide are disposed on the guides 21 and 47. The guides 21, 22, 23
and 24 are support members 63 placed on the table 20 so that the guides 21 and 22 and the guides 23 and 24 facing each other are at right angles with the turntable 25 at the center.
(Fig. 4, Fig. 5).

The positioning member 30 has a backing plate 55 which is a cushioning material on the surface that comes into contact with the workpiece 4, and the table 2
The connecting arm 37 is rotatably supported by a bearing 38 on the positioning member 30, and is connected to the connecting arm 37 via a long hole _37a by a connecting pin 39 provided on the positioning member 30.
An air cylinder 40, which is a first driving means for the positioning member 30, is connected to the connecting arm 37. Further, the holding member 29 has a backing plate 56 which is a cushioning material on the surface that comes into contact with the workpiece 4, and a connecting arm 43 which is swingably supported on the table 20 by a bearing 42 is attached to the holding member 29. connected via the provided connecting pin 41 and elongated hole 43 _a ,
An air cylinder 40 _b (shown in the fourth figure), which is a second driving means for the pressing member 29, is connected to the connecting arm 43.

As shown in FIG. 5, for example, the presser member 29 includes rollers 31, 32, which are driven along a guide 21 attached to the table 20 via a support member 63.
It slides while being guided by the guide 21 by 33, 34 and 36. That is, the rollers 32 and 33 are attached to the left and right mounting plates 29 _b provided on the lower surface of the presser member 29, and the guide 21 is vertically sandwiched between the rollers 34 and 31 provided at the lower part of the mounting plates 29 b, respectively. Roller 3 provided on mounting plates 29 _b and 29 _b
6 and 36 sandwich the guide 21 in the left-right direction, thereby guiding the presser portion member 29 along the guide 21 in the left-right and up-down directions. Another pressing member 48,
The same applies to the positioning members 47 and 30.

In order to make the device compact, the air cylinder _40b (the same applies to other air cylinders) is disposed below the table 20, as shown in FIG. The upper arm _43b and the lower arm _43c are integrally connected, and the presser member 29 is connected to the upper arm _43b as described above, and the lower arm _43c is connected to an air cylinder. 40 _b are connected. Further, the connecting arm 45 for driving the positioning member 30 along the guide 22 has a similar structure to that described above.

However, since the positioning member 30 needs to stop accurately at a predetermined reference position, the positioning member 3
When the positioning member 30 moves a certain distance along the guide 22, a stopper 46 whose position can be adjusted stops the positioning member 30 at a predetermined position.
0.

Further, since the positioning member 30 and the holding member 29 are configured to slide facing each other with the workpiece 4 in between, even if the positioning member 30 is pushed by the holding member 29 through the workpiece 4, the positioning member 3
0 must be configured to ensure a predetermined position. Therefore, the positioning member 30 is biased by the air cylinder 40, which is the first driving means.
The connecting arms 37, 43 are arranged so that the urging force on the workpiece 4 is greater than the urging force on the workpiece 4 of the pressing member 29, which is urged by the air cylinder 40b (shown in the fourth figure), which is the second driving means. Adjust the length of the air cylinders 40, 40b and the force of the air cylinders 40, 40b. The positioning member 30, the holding member 29, the air cylinders 40, 40b, etc. as described above are included in the third
A mechanism for positioning the workpiece 4 in the X-axis direction in the embodiment shown in the figure is configured.

Also, a positioning member 47 that is slidably attached to the guide 23, an air cylinder _40a (shown in the fourth figure) that drives the positioning member 47, and an arm 49 that connects the air cylinder _40a and the positioning member 47. and a holding member 48 that is slidably attached to the guide 24, an air cylinder (not shown) that drives the holding member 48, and a connecting arm 50 that connects the air cylinder and the positioning member 48. Then, arrow Y (X
A mechanism for positioning the workpiece 4 in the (perpendicular to) direction is constructed, and its structure is the same as the mechanism for positioning the workpiece in the X-axis direction.

By the way, it is necessary to detect whether or not the workpiece 4 is positioned in a normal state, so in the workpiece positioning device according to the above embodiment, the hole H (this hole The hole detection sensors 57 and 58, which are composed of magnetic sensors, etc., that detect the position of
and the positioning member 47, and when the positioning operation is completed, that is, the positioning member 30 (or 4
7) and the holding member 29 (or 48), the directionality of the workpiece can be confirmed by detecting the presence or absence of the hole H at a predetermined position using the hole detection sensors 57 and 58. It has a structure.

The positioning member 47 is used for accurate positioning, especially in order to prevent positioning in a twisted state _4a of the workpiece 4, the positioning block 47a of the positioning member ₄₇ , which serves as a reference for positioning the workpiece, is connected to the other three positioning blocks. 30 _a , 48 _a , and 29 _a (length sufficient for accurate positioning).

Note that the holding member 4 facing the positioning member 47
8 is also provided with a stopper 59 in order to prevent the holding member 48 from overrunning when the workpiece 4 is not placed on the turntable 25.

The operation of the workpiece positioning device according to the above embodiment will be explained below.
0, the holding member 29 and the opposing positioning member 4
7 and the pressing member 48 are respectively driven by the driving means 4.
Release the air cylinders 40, _40a , _40b , etc. at the locations shown in FIG.
(shown in the second figure) places the workpiece 4 transported from a predetermined position on the turntable 25. In this case, the turntable 25 has a table surface that protrudes beyond the table 20, and the turntable 25
Since the mounting surface of No. 5 is parallel to the table 20, even if the side surface of the work has an edge bent at the bottom, as shown in a, b, and e in FIG. is placed parallel to the

After that, after confirming that the workpiece 4 is placed on the turntable 25, the positioning member 47 and the holding member 48, which are part of the positioning mechanism in the Y-axis direction shown in FIG. By operating an air cylinder _40a or the like (see FIG. 4) serving as a driving means, the workpiece 4 is driven in a direction to sandwich the workpiece 4 via the connecting arms 49 and 50. In this case, since the biasing force of the positioning member 47 to the workpiece 4 is greater than the biasing force of the holding member 48 to the workpiece 4, the positioning member 47 is always stopped in contact with the stopper 51 (47'), and the holding member 48 stops (48') at a position sandwiching the work 4 with reference to the stopped positioning member 47'. This state is shown in the positioning member 47' and the holding member 48' shown by two-dot chain lines in FIG.

When the positioning of the workpiece 4 in the Y-axis direction is completed as described above, positioning in the X-axis direction is not possible as it is, so the positioning member 47'
and the holding member 48' are respectively attached to the air cylinder 4.
_0a , etc., through the connecting arms 49 and 50, and moves in the direction of the original position, thereby releasing the pressing force by the air cylinder in the Y-axis direction. However, the pressing force exerted by the air cylinder _40a may be released by temporarily lowering the air pressure within the air cylinder _40a , which is the driving source.
Thereafter, the positioning member 30 and the holding member 29, which are part of the positioning mechanism in the X-axis direction, are driven by the air cylinders 40 and _40b via the connecting arms 37 and 43 in a direction to sandwich the workpiece 4. Note that when releasing the positioning of the workpiece 4 in the Y-axis direction, if the positioning member 47' retreats first,
Since the workpiece 4 may be pushed in the direction of the positioning member 47' by the holding member 48', the holding member 4 prevents the positioning member 47' from returning to its original position.
It is desirable that the retraction of 8' to its original position be delayed somewhat.

As mentioned above, the positioning mechanism in the X-axis direction is configured similarly to the positioning mechanism in the Y-axis direction, so the positioning member 30 moves to a predetermined position and comes into contact with the stopper 46 and stops (30 ')death,
The holding member 29 stops with the workpiece 4 sandwiched therebetween with reference to the positioning member 30'(29').
This positions the workpiece 4 in the X-axis direction. When performing this positioning in the X-axis direction,
Since the Y-axis direction is not positioned, there is a risk of some deviation. Therefore, after positioning in the X-axis direction, positioning in the Y-axis direction is performed again using the positioning member 47 and the holding member 48.

Even if the loaded state of the workpieces 4 shown in FIG. 2 is slightly shifted in the X and Y directions through the above process, the workpieces 4 placed on the surface of the turntable 25 by the work loader 60 will be accurate in the X and Y directions. It is positioned at

However, since the workpiece 4 according to the above embodiment has a rectangular plane, it may be incorrectly positioned at a position rotated 180 degrees from the predetermined position, and if it is transported to the next process as it is, This causes the inconvenience that the pins 6, 7, 8, or 9 (shown in the first figure) may not be attached. Therefore, while positioning both the X-axis direction and the Y-axis direction, the hole detection sensors 57' and 58' (indicated by two-dot chain lines in FIG. 3) detect holes H that are asymmetrically provided in the workpiece 4.
(see Figure 6), and workpiece 4 is detected in the normal state.
is positioned, the hole detection sensor 5
In response to the signals 7' and 58', both the positioning mechanisms in the X-axis direction and the Y-axis direction are released, and the workpiece 4 is taken out by the second work loader 61 and transported to the next process. However, as a result of detecting holes in the workpiece 4 by the hole detection sensors 57' and 58', if the state is not normal, the signals from the hole detection sensors 57' and 58' are received, and the The direction positioning mechanism is released, and the rotary cylinder 28 provided at the bottom of the table 20 is driven to rotate the turntable 25 and the workpiece 4 placed thereon by 180 degrees, thereby aligning it with the X-axis direction described above. After positioning in the Y-axis direction again, the second work loader 61
It is transported to the next process. As a result, the work 4 is accurately positioned and placed on the pallet on the first conveyor 13.

In the workpiece positioning device according to the above embodiment, after once accurately positioning the workpiece 4, the holes H provided asymmetrically in the workpiece 4 are detected.

Therefore, even if the hole H detected by the hole detection sensor 57' or 58' is small, it is possible to accurately detect the presence or absence of the hole H.

In the above embodiment, whether or not the workpiece 4 is in a predetermined position is detected by detecting the hole H provided asymmetrically in the workpiece 4. Alternatively, it is also possible to detect whether the work 4 is placed at a predetermined position by using a sensor to detect a unique shape provided on the work 4, such as a notch.

Furthermore, in the above embodiment, two sensors 5
7 and 58 are used to detect the asymmetric hole H in the workpiece 4. This is to increase the accuracy of the hole detection, and in some cases it may be sufficient to use only one of the sensors 57 or 58.

As described above, the gist of the present invention is to provide an apparatus for positioning an asymmetrical workpiece at a predetermined position, including a turntable on which the workpiece is placed, and a planar view of the workpiece on the turntable. positioning members that are individually driven to move from the X and Y directions to predetermined reference positions set in advance; and positioned opposite to each of the positioning members,
A holding member is moved and driven separately with a biasing force smaller than that of each positioning member and holds the workpiece between the positioning members, and the workpiece is held between the positioning member and the holding member from the X and Y directions. a sensor for detecting an asymmetrical portion of the workpiece in a positioned state; a driving means for rotating the turntable by a predetermined angle in response to a signal from the sensor; and a drive means for rotating the turntable by a predetermined angle together with the turntable. Since the workpiece positioning device is characterized by having positioning means for moving and driving the positioning member and the holding member with respect to the workpiece on the table and repositioning the workpiece, the asymmetrical shape workpiece can be Even if it is mounted on a positioning turntable in a 180-degree rotated state, the detection accuracy is extremely high because the state is detected once it has been accurately positioned. Furthermore, since the position is automatically corrected to the normal state and the positioning is performed accurately again, the efficiency of the entire work flow can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is an assembly process diagram of a copying machine chassis including a workpiece used in an embodiment of the present invention, and FIG. 2 is a plan view of an automatic assembly line for the chassis including a workpiece positioning device according to an embodiment of the present invention. 3 is a plan view of a workpiece positioning device according to an embodiment of the present invention, FIG. 4 is a side view of the same, FIG. 5 is an enlarged side view of a portion viewed from arrow A in FIG. 4, and FIG. Sectional view of arrow B in FIG. 3 in a clamped state, No. 7
The figure is a sectional view taken along the line CC in FIG. 3. (Explanation of symbols), 4... Work, 25... Turntable, 26... Free bear, 28... Rotary cylinder (driving means), 29, 48... Holding member, 30, 47... Positioning member, 57, 58
...Hole detection sensor (sensor), H...Hole (asymmetrical part of workpiece).

Claims (1)

[Claims] 1. A device for positioning an asymmetrical workpiece at a predetermined position, comprising: a turntable on which the workpiece is placed; a positioning member that is individually driven to move to a predetermined reference position that has been set; a holding member that clamps a workpiece; a sensor that detects an asymmetrical portion of the workpiece in a state where the workpiece is positioned by being held between the positioning member and the holding member from the X and Y directions; a driving means for rotating the turntable by a predetermined angle in response to a signal; and a driving means for moving and driving the positioning member and the holding member with respect to the work on the turntable which has been rotated by the predetermined angle together with the turntable to rotate the work again. A workpiece positioning device comprising: positioning means for positioning a workpiece.