JPH0645090B2 - Supply status detector for small parts - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a supply state of small parts such as a welding nut supplied to a predetermined portion of a work.

2. Description of the Related Art When a nut is welded and fixed to a sheet metal work to form a threaded portion, a small part generally called a weld nut is used.

The welding nut is, as shown in FIG. 10 and FIG. 11,
A female screw portion (2) is formed in the center of a substantially rectangular plate-shaped main body (1), and small projections (3) (3) ... Are formed at the four corners of the main body (1) toward the lower outside. It is a thing.

The welding nut (N) is positioned and supplied so as to be concentric with the bolt hole (4) formed in the flat plate-shaped work as shown in FIG. (N) is pressed by a pair of upper and lower electrodes and is energized to generate an electric current that concentrates on the small protrusions (3) (3) ... And the small protrusions (3) (3). It is welded by melting the contact portion with the small protrusions (3).

As described above, the welding device for the welding nut (N) has been
The one shown in FIG. 13 is generally used and will be described below with reference to the drawings.

In the drawings, (11) is a lower electrode erected on a table (not shown), (12) is a welding gun arranged on the same axis above the lower electrode (11), and (13) is welding. The supply device of a nut (N) is shown.

The lower electrode (11) is provided at its center with a guide pin (14) made of an insulating material such as ceramic.

As shown in FIG. 14, the guide pin (14) is formed with a small diameter so that the tip can be fitted into the female screw part (2) of the welding nut (N), and the intermediate part of the work (W) is formed. It has a shape fitted into the bolt hole (4) and set to a diameter capable of supporting the main body (1) of the welding nut (N),
The lower electrode (11) is arranged on the same axis as the lower electrode (11) so as to project and retract, and is always urged upward by a spring (15) incorporated in the lower electrode (11).

The welding gun (12) has an electrode tip, that is, an upper electrode (17) disposed at the tip of a piston rod (16a) of a gun cylinder (16). The upper electrode (17) is the lower electrode. The piston rod (16a) projects and retracts with respect to the gun cylinder (16) so as to be linearly reciprocated toward the lower electrode (11).

The nut supply device (13) is configured to supply the work (W),
The welding nut (N) is directed in a predetermined direction toward the guide pin (14) protruding from the work (W), that is, the small protrusion (3).
(3) is cut out and supplied one by one with the ... facing downward.

A procedure for fixing the welding nut (N) to the work (W) by the welding device (A) will be described.

First, as shown in FIG. 14, the work (W) is positioned and supplied on the lower electrode (11) with the bolt holes (4) fitted in the guide pins (14).

Next, as shown in FIG. 15, a welding nut (N) is supplied to the tip of the guide pin (14) protruding from the work (W) by the nut supply device (13). In this state, the bolt hole (4) of the work (W) and the female screw portion (2) of the welding nut (N) are coaxially positioned by the guide pin (14), and The small projections (3) (3) on the lower surface of the welding nut (N) are in contact with the surface of the work (W).

Next, as shown in FIG. 16, the piston rod (16a) is extended from the gun cylinder (16), and the upper electrode (1
While the welding nut (N) is being pressed toward the work (W) on the lower electrode (11) by 7), electricity is passed between the electrodes (11) and (17) in this state to apply the welding nut (N). )
Of the small protrusions (3), (3), and the contact portion of the small protrusions (3), (3) on the work (W) are melted, and the welding nut (N) is fixed to the work (W) by welding.

Finally, the above energization is interrupted, and the piston rod (16a) of the gun cylinder (16) is moved in and out to move the upper electrode (17).
Is returned to the original position, and the work (W) to which the welding nut (N) is fixed is carried out.

After that, a new work (W) is positioned on the lower electrode (11) in a state of being positioned by the guide pin (14), and the welding nut (N) may be sequentially fixed as described above.

Problems to be Solved by the Invention The above conventional device has the following problems.

The small parts supplied from the nut supply device (13) toward the work (W), that is, the welding nut (N) are not always supplied to the guide pin (14) in a surely fitted state. , It may be supplied to the guide pin (14) in a tilted state or may come off the guide pin (14).

As described above, when the welding nut (N) is supplied in an inclined state with respect to the guide pin (14), the welding nut (N) and the work (W) are pressed by the upper electrode (17) in the next step. Then, a force in a twisting direction is applied to the guide pin (14), and the guide pin (14) may be broken.

Even if the guide pin (14) is not broken, the welding nut (N) may be welded in a state where it is out of a predetermined position.

Then, the positional deviation is hard to detect by visual observation, and therefore, the positional deviation is fixed, and when the welding nut (N) is fixed in such a positional deviation, the positional deviation can be found only in the subsequent process. The defective product thus obtained had to be discarded because the welding nut (N) could not be fixed again.

Further, when the welding nut (N) is supplied upside down, that is, when the small protrusions (3) (3) ... Are supplied upward, the workpiece (W) cannot be welded, It is necessary to remove the welding nut (N) and supply a new welding nut (N) again, which is troublesome.

Means for Solving Problems The present invention has been made in view of the above problems, and supplies small parts to a predetermined position on a work in a predetermined direction, and fixes the small parts to the work in a post process. In things,
A detection mechanism that detects the supply state of the small parts to the work, and a moving mechanism that moves the detection mechanism at least in the vertical direction with respect to the small parts on the work, and the detection mechanism is at least the upper part of the small parts. A main body having a recessed portion that can be externally fitted in the recessed portion, a push-out member disposed in the recessed portion so as to project and retract, and a non-contact sensor that detects the presence or absence of small parts disposed in the recessed portion. The moving mechanism includes an arm pivotally attached to a slide block at a base end thereof and swingable in association with vertical movement of the slide block, and an arm provided at a lower end of the arm, and a detection mechanism is provided by lowering the slide block. The non-contact type that operates by reacting to the small parts that come into contact with the lower surface of the pressing member by swinging the main body concave part of the body to a position that coincides with the axis of the predetermined position of the small parts And a sensor for detecting a position and a state in which a small component supplied onto a work is inserted, and a supply state detecting device for a small component.

Effect The small component supply state detection device according to the present invention moves the detection mechanism toward the work by the moving mechanism, and the small component supplied on the work is fitted into the recess formed in the main body of the detection mechanism. By detecting this by the sensor, it is possible to determine that the small parts are supplied to the proper position and in the normal state prior to the fixing of the small parts to the work in the subsequent process.

Embodiment FIG. 1 to FIG. 9 show an embodiment of a supply state detecting device for small parts according to the present invention. In this embodiment, the small parts are the above-mentioned welding nuts, and It is provided as a device to be attached and used.

In the drawings, (20) is a base block disposed in the welding device (A) for mounting the device (B) of the present invention, and (30) is disposed with respect to the base block (20). A moving mechanism (50) indicates a detection mechanism arranged on the moving mechanism (30).

In this embodiment, the base block (20) is fixed to the gun cylinder (16).
A moving mechanism (30) described below is provided by using the 0).

A linear drive mechanism, for example, an air cylinder (32) is provided at the base end of the front surface of the base block (20), and guide bars (33 extending vertically are provided on both sides thereof.
a) and (33b) are slidably arranged. The upper ends and lower ends of the guide bars (33a) and (33b) are integrally connected by connecting rods (34a) and (34b) having a rectangular column shape.

An upper part of the base block (20) passes through a substantially central portion of the upper connecting bar (34a), and the connecting bar (34a)
A shaft member (35) protruding upward from the shaft member is erected. A portion of the shaft member (35) protruding from the connecting bar (34a) and the connecting bar (34a).
A stopper block (36a) is provided at each of the lower portions.
(36b) is provided, and the stopper block (36b
The vertical movement range of the guide bars (33a) and (33b) is set by adjusting the distance between a) and (36b) and the vertical position.

Further, guide bars (33a) (33) for the base block (20) are provided on the upper left side of the base block (20).
The sensor (61) for detecting the lowermost position of b) is
It is arranged via a bracket (60). The sensor (61) is, for example, a proximity switch, and in the proximity switch (61), the connecting bar (34a) abuts on the lower stopper block (36b), so that the guide bar (33a).
When the (33b) is at the lowest position, it reacts with the operating piece (62) fixed to the left end of the connecting bar (34a).

Further, the upper end of the base block (20) and the connecting bar (34
A spring (37) is interposed between the shaft member (a) and the shaft member (35) coaxially with the shaft member (35) so that the guide bars (33a) (33b) are always directed upward by the spring (37). Repressed.

A slide block (38) is disposed between the lower connecting bar (34b) of the guide bar (33a) (33b) and the base block (20). The slide block (38) is slidable in the axial direction with respect to the guide bars (33a) (33b) in a state where both sides thereof are penetrated by the guide bars (33a) (33b). The tip of the piston rod (32a) of the air cylinder (32) is fixed to the slide block (38) via the bracket (39). The lowermost position of the slide block (38) on the guide bars (33a) (33b) is set by the adjusting bolt (40) arranged on the connecting bar (34b).

A base end portion of a first arm (41) for arranging the detection mechanism (50) is pivotally attached by a pin (42) to the right of the central portion of the lower connecting bar (34b). (Four
1) is swingable around the pin (42).

On the lower left side of the lower end of the slide block (38), a base end portion of a substantially U-shaped second arm (43) is swingable around a pin (44).

A connecting arm (45) having a substantially V shape is further integrally fixed to the tip of the second arm (43) at the base end thereof, and the tip of the connecting arm (45) is a pin. (46)
Is connected to a substantially middle portion of the first arm (41).

The detection mechanism (50) is housed in a main body (51) fixed to the lower end of the first arm (41) and a recess (52) formed in the main body (51) as shown in FIG. The main components are a pressing member (53) and a non-contact sensor housed in the recess, such as a proximity switch (54).

The main body (51) is made of a non-magnetic material such as aluminum so as to correspond to the proximity switch (54), and is fixed to the rear surface side of the tip of the first arm (41) by a base portion.
First arm (41) in the state of FIG. 5 or FIG.
Extends toward the rear left side of.

The lower surface of the tip of the main body (51) projects downward as shown in FIG. 4, and a through hole (55) is formed coaxially with the projecting portion (51a). A lid (56) is screwed onto the upper part of the through hole (55), and the lid (56) forms a recess (52) by closing the upper end opening of the through hole (55).

The inner peripheral surface on the lower end side of the through hole (55) is set in such a size that the main body portion of the welding nut (N) can be fitted with a predetermined tolerance, and the lower end side opening of the through hole (55). A predetermined taper surface (55a) is formed on the peripheral edge of the part.

The pressing member (53) is made of a non-magnetic material such as aluminum so as to correspond to the proximity switch (54), and the flange portion (53a) formed on the upper portion is provided in the through hole (55). It is loosely fitted in the large diameter portion (55b) of the central portion and is slidably accommodated along the axial direction of the through hole (55). The pressing member (53) has a circular hole (53
b) is bored, and the spring (57) housed in the round hole (53b) is compressed between the spring (57) and the lid body (56) so that the pressing member (53) is always directed downward. Are urging.

A guide protruding from the welding nut (N) at the center of the lower end surface of the pressing member (53) when the lower end surface abuts the upper surface of the welding nut (N) supplied to the work (W). Round hole (53c) to avoid interference with the tip of pin (14)
Is formed, and a notch (53d) for avoiding interference with the proximity switch (54) is formed on one side of the lower end surface.

A housing hole (58) is formed through the upper surface of the main body (51) from the side toward the lower end of the through hole (55), and the proximity switch (54) is located in the housing hole (58). Has been inserted. The proximity switch (54) has the through hole (55).
With the welding nut (N) fitted therein, the welding nut (N) is attached at a position where the upper end surface of the welding nut (N) does not abut.

The procedure for detecting the supply state of the welding nut (N) by the detection device (B) will be described below. The above detection device (B)
In the initial state, as shown in FIG. 1, the piston rod (32a) of the air cylinder (32) is in the retracted position, and the first arm (41) is in a state of swinging sideways. In addition, the work (W) is positioned and mounted on the lower electrode (11) with the bolt holes (4) fitted in the guide pins (14) as described above, and is placed on the work (W). It is assumed that the welding nut (N) has already been supplied by the nut supply device (13).

First, the piston rod (32a) of the air cylinder (32) is extended from the first state. In this state, the guide bars (33a) (33b) are connected to the connecting bar (34a) and the stopper block (36) by the urging force of the spring (37).
Therefore, the slide block (38) descends along the guide bars (33a) and (33b) by the extension operation of the piston rod (32a).

The lowering of the slide block (38), that is, the movement of the slide block (38) toward the connecting bar (34b) on the lower side swings to the first arm (41) via the second arm (43). This is transmitted as a motion, and the first arm (41) swings vertically below the pin (42).

Then, the swinging motion of the first arm (41) is continued until the lower end of the slide block (38) comes into contact with the tip of the adjusting bolt (40) arranged in the connecting bar (34b), and the slide block is moved. When the (38) comes into contact with the adjusting bolt (40), the first arm (41) is positioned in the vertical direction, and the recess (52) of the detection mechanism (50) is
It is located above the guide pins (14) with their axes aligned.

Then, the piston rod (32
When a) is further extended, the slide block (38) presses the connecting bar (34b) via the adjusting bolt (40), and the guide bar (33) with respect to the base block (20).
The first arm (41) and the detection mechanism (5) while compressing the spring (37) between the a) (33b) and the connecting bar (34a) above the base block (20).
0) is lowered.

If the supply state of the welding nut (N) onto the work (W) is in the normal state or slightly deviates from the normal state, the welding nut (N) is turned upside down. In the case where the welding nut (N) is completely deviated from the normal position, it will be described separately in four cases.

First of all, the welding nut (N) is in a proper state, that is, the guide pin (14) causes the bolt hole (4) of the workpiece (W)
When the small protrusions (3), (3), ... Are in contact with the work (W) in a coaxial state with the work (W), the detection mechanism (50) is lowered to first move the main body (51) from the main body (51). The lower surface of the projecting pressing member (53) abuts on the upper surface of the main body (1) of the welding nut (N) supplied in the above-described normal state, and thereafter, due to the different lowering of the detection mechanism (50), The pressing member (53) is pushed into the recess (52) against the urging force of the spring (57), and the main body (1) of the welding nut (N).
Fits into the recess (52). The lowering operation of the detection mechanism (50) is continued until the connecting bar (34a) contacts the stopper block (36b), and when the connecting bar (34a) contacts the stopper block (36b), the base is removed. The proximity switch (61) arranged in the block (31) detects that the detection mechanism (50) has reached the lowest position. At the lowermost position of the detection mechanism (50), as shown in FIG. 7, the notch (53) is formed due to the retraction of the pressing member (53).
The proximity switch (54) is exposed from d), and the proximity switch (54) operates by reacting with the upper surface of the welding nut (N) that abuts the lower surface of the pressing member (53) to operate the welding nut (N). ) Is supplied to the normal state.

As described above, when it is detected that the welding nut (N) is being supplied in the proper state, the piston rod (32a) of the air cylinder (32) is retracted. Then, the detection mechanism (50) ascends while pressing the welding nut (N) toward the work (W) from the inside of the recess (52) by the pressing member (53) while keeping the supply state as described above. Through the reverse operation, the state of FIG. 1 is restored. In this state, the upper electrode (17) is located vertically above the guide pin (14), and the upper electrode (17) extends the piston rod (16a) of the gun cylinder (16) as described above. The welding nut (N) is pressed down toward the work (W) on the lower electrode (11) of the welding nut (N), and both electrodes (11) and (17) are pressed.
The welding nut (N) can be securely fixed to a predetermined position of the workpiece (W) by energizing the workpiece (W).

Secondly, when the welding nut (N) is slightly displaced or tilted from its normal position, the welding nut (N) is
After the contact between the pressing member (53) and the pressing member (53), the main body (1) of the welding nut (N) contacts the tapered surface (52a) of the recess (52),
Since the main body (1) is guided to the recess (52) by the tapered surface (52a), the welding nut (N) is corrected to the normal position. Therefore, in this case, the main body (1) of the welding nut (N) is fitted in the recess (52) and the proximity switch (5
4) Detected as having been supplied to the normal state.

Thirdly, when the welding nut (N) is supplied upside down, that is, when the small protrusions (3) (3) ... Are supplied upward, as shown in FIG. Since the small protrusions (3) (3) of (N) come into contact with the protruding portion (51a) of the lower surface of the main body (51) of the detection mechanism (50), the welding nut (N) is naturally provided in the recess (52). Does not fit in. Therefore, since the detection mechanism (50) does not move to the lowermost position, the proximity switch (61) on the base block (31) side and the proximity switch (5) on the detection mechanism (50) side.
4) does not operate, and it is detected that the welding nuts (N) are being supplied upside down because the proximity switches (61) (54) are not operated. In this case, the detection mechanism (50)
1 is returned to the state shown in FIG. 1, the welding nut (N) supplied in the upside-down direction is removed by an appropriate means, and then the welding nut (N) is newly supplied from the nut supply device (13).
Is supplied and the detection mechanism (50) is operated as described above.

Fourth, when the welding nut (N) is completely out of the normal state, for example, when the welding nut (N) supplied toward the guide pin (14) comes out of the guide pin (14). Or, when the welding nut (N) is not supplied at all due to a failure of the nut supply device (13),
As shown in FIG. 9, of course, there is nothing that fits into the recess (52) of the detection mechanism (50), and therefore the detection mechanism (50) descends to the lowest position. In this state, the proximity switch (61) on the side of the base block (20)
Although it is detected by the detection mechanism (50) that it has moved to the lowest position, the welding nut (N) is fitted into the recess (52) by the proximity switch (54) of the detection mechanism (50). Is detected. That is, the welding nut (N) is supplied to the guide pin (14) by the operation of the proximity switch (61) on the base block (20) side and the non-operation of the proximity switch (54) on the detection mechanism (50) side. Not detected. In this case, after the welding nut (N) is supplied again in the same manner as described above, the detection mechanism (5
0) and the moving mechanism (30) may be operated.

As described above, the device (B) of the present invention is the welding nut (N).
Since the supply state of the welding nut (N) to the workpiece (W) can be detected prior to the fixation of the welding nut (N), the welding nut (N) can be securely fixed to a predetermined position of the workpiece (W).

In the above description, the small parts are described as the welding nuts, but the present invention is not limited to the welding nuts, and can be easily applied to small parts having different shapes in the axial direction, such as welding bolts.

Effects of the Invention As described above, the supply state detection device for small parts according to the present invention moves the detection mechanism toward the work by the movement mechanism, and in the recess formed in the main body of the detection mechanism,
By detecting that the small parts supplied on the work have been fitted by the sensor, the fact that the small parts have been supplied to the regular position, and in a normal state, is added to the work of the small parts in the subsequent process. Since it is possible to make a distinction prior to the fixing, the small parts can be accurately fixed to the work at the proper positions, and the generation of defective products can be completely prevented.

[Brief description of drawings]

1 to 8 show an embodiment of a supply state detecting apparatus for small parts according to the present invention. FIG. 1 is a front view of the detecting apparatus in an initial state, and FIG. 2 is FIG. I-I
FIG. 3 is a cross-sectional view taken along line II-II in FIG. 1, FIG. 4 is a cross-sectional view taken along line III-III in FIG. 3, and FIGS. FIGS. 7 to 9 are front views in respective operating states for explaining the operation of the moving mechanism in the detection device, and FIGS. 7 to 9 are sectional views for explaining the operation of the detection mechanism in the detection device. 10 and 11 are a plan view and a vertical side view showing an example of a welding nut, FIG. 12 is a vertical side view showing a state in which the welding nut is fixed to a flat plate-like work, and FIG. 13 is a conventional welding. FIG. 14 is a front view showing an example of the apparatus, and FIG. 14 to FIG. 16 are longitudinal side views of essential parts for explaining the procedure of fixing the welding nut by the welding apparatus. (W) …… Workpiece, (N) …… Welding nut [small parts], (13) …… Supplier, (30) …… Movement mechanism, (50) …… Detection mechanism, (51) …… Detection mechanism Main body of (52) …… recess, (53) …… pressing member, (54) …… proximity switch [sensor].

Claims (1)

[Claims] 1. A detection mechanism for supplying a small component to a predetermined position on a work in a predetermined direction and fixing the small component to the work in a later step, the detection mechanism detecting a supply state of the small component to the work. The detection mechanism includes a moving mechanism that moves the small component on the workpiece in at least the vertical direction, and the detection mechanism includes a main body having a concave portion that can be externally fitted to the upper portion of the small component, and the concave portion. A pressing member arranged so as to project and retreat inside, and a non-contact type sensor arranged to detect the presence or absence of small parts arranged in the recess. An arm that is pivotally attached and can swing in relation to the vertical movement of the slide block, and an arm provided at the lower end of the arm. It is equipped with a non-contact sensor that swings to a position that coincides with the axis and further descends vertically, and that operates in response to small parts that come into contact with the lower surface of the pressing member. An apparatus for detecting a supply state of small parts, which detects a position and a state.