JP2969083B2 - Nozzle tip mounting mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle tip mounting mechanism, and more particularly to a nozzle tip mounting mechanism for sequentially and automatically mounting a plurality of arranged nozzle tips.

[0002]

2. Description of the Related Art A dispensing apparatus for dispensing a sample is conventionally known. For example, a plurality of specimens such as blood or serum collected from the human body and reagents for performing predetermined processing by mixing with the specimens are stored in a storage container. It is used as a device for dispensing into small containers. That is, a predetermined amount of the sample or the reagent is aspirated from the storage container by the vacuum suction device or the like, and is discharged to the predetermined small container. In such a dispensing apparatus, usually, various kinds of specimens and reagents are continuously processed, so that a suction nozzle (hereinafter, referred to as a nozzle base) of the vacuum suction apparatus is a suction target in order to prevent mixing and contamination. Each time it changes or each time it is aspirated, it must be replaced with a new one. Therefore, conventionally, a disposable (disposable) nozzle tip mainly composed of an inexpensive resin such as a hard plastic has been used. Many mechanisms have been proposed for automatically mounting the nozzle tip to the nozzle base of a vacuum suction device of a dispensing device.

For example, FIG. 6 shows a schematic configuration diagram of a conventional nozzle tip mounting mechanism 100. Nozzle head 108 including nozzle base 106 on which a plurality of nozzle tips 104 held upright on tip rack 102 are mounted
Is supported by an XY arm (not shown) and is movable in a horizontal plane in any direction, and is also movable in a vertical direction along a guide rail 110 arranged vertically on the XY arm. It has become. Accordingly, the nozzle base 106 moves right above the nozzle tip 104 prepared at an arbitrary position on the tip rack 102, and at the same time, moves down and presses toward the nozzle tip 104, thereby mounting the nozzle tip 104. it can.

When the nozzle base 106 is mounted on the nozzle tip 104, the nozzle base 106 is attached to the nozzle tip 104 with a sufficient force in order to prevent the nozzle base 104 from dropping off after mounting, breakage of the nozzle tip 104, and excessive addition to the mounting mechanism. Must be inserted. Therefore, the nozzle head 10
A spring 112 capable of urging the nozzle base 106 with a predetermined urging force is disposed inside the nozzle 8. Nozzle base 10
6 is a predetermined amount after contacting the nozzle tip 104, for example, 5 mm
When descending, the spring 112 is compressed to a predetermined urging force,
For example, at 3 kgf, the nozzle base 106 is
4 and is mounted.

On the other hand, when mounting the nozzle tip automatically, it is necessary to consider a movement error of the nozzle base. For example, if the lowered position of the nozzle base shifts and the nozzle base comes into contact with a chip rack or the like, damage to the nozzle base or the driving source is caused. As a countermeasure, a spring having a small spring constant and a spring having a large spring constant are arranged in series. First, a spring having a small spring constant is compressed, and after a predetermined amount of compression, a spring having a large spring constant is compressed to a predetermined urging force (for example, 3 kg).
f). At this time, it is detected whether the compression start position of the spring having a small spring constant is different from the position at the time of normal mounting, and if it is different, the lowering of the nozzle base is stopped. As a result, the urging force acting on the nozzle base and the driving source can be only the urging force of a spring having a small spring constant, and the impact given to the mechanism can be reduced.

That is, the lowest point of the lowering of the mounting operation with respect to an arbitrary nozzle tip serving as a reference is registered in advance, and based on the lowest point, the control of the mounting of the nozzle tip, the detection of the quality of the mounting, and the compression amount of the spring are determined. Continuous automatic mounting of nozzle tip.

[0007]

However, the shape and dimensions of the nozzle tip, which is a resin molded product, vary greatly. When the nozzle tip is set up and stored in the storage hole of the chip rack, the height of the nozzle tip is reduced. Variations occur.
As described above, the registration of the lowermost point of the descent is performed using an arbitrary nozzle tip as a representative. The amount of compression of the spring changes. As a result, the mounting force of the nozzle tip varies. For example, if the outer diameter of the nozzle tip at the time of registration of the lowest point of descent is smaller than a predetermined value, the nozzle tip is held at a position lower than the predetermined position, and registration is performed at that position. Therefore, the nozzle base is excessively lowered with respect to another predetermined size of the nozzle tip, and the nozzle base is pressed against the nozzle tip by an excessive urging force, which may cause damage to the nozzle tip or damage to the mounting mechanism due to excessive addition. Invite. Conversely, when the outer diameter of the nozzle tip is larger than the predetermined value, the nozzle tip is held at a position higher than the predetermined position, and when registration is performed at that position, the nozzle base of the nozzle base of another predetermined size is Insufficient descent results in lack of bias. As a result, there is a problem that the nozzle tip falls off from the nozzle base during the dispensing or the like.

Furthermore, it is desirable to shorten the machine cycle (spring compression stroke) of the mounting mechanism.
Therefore, as described above, when one of the springs has a small spring constant, the compression stroke becomes long, so that the other spring needs to generate a large urging force with a shorter stroke. In other words, it is necessary to use a spring with a large spring constant, but if there is variation in registration of the lowest point of descent, a spring with a large spring constant will cause a large change in the biasing force for a subtle change in the compression stroke. . As a result, there is a problem that the influence on the damage of the nozzle tip, the addition of the mounting mechanism, or the drop off of the nozzle tip increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and even if an error occurs in registration of the lowermost descent point for mounting the nozzle tip, the nozzle base with respect to the nozzle tip can be removed. It is an object of the present invention to provide a nozzle tip mounting mechanism having a simple configuration capable of minimizing the fluctuation of the urging force.

[0010]

In order to achieve the above-mentioned object, the present invention provides a nozzle tip mounting mechanism for urging a nozzle base and press-fitting the nozzle tip into a nozzle tip. A first nozzle bracket for urging the nozzle bracket according to an elastic deformation amount;
A spring and a spring which is elastically deformed in advance by a predetermined amount and generates a primary urging force. The spring is further elastically deformed from the predetermined amount and generates a secondary urging force in accordance with the deformation amount to urge the nozzle bracket. Transmission control for stepwise urging the nozzle base via the nozzle bracket based on the urging force of the first spring and the second spring in accordance with the press-fit state of the second spring and the nozzle base to the nozzle tip. Means.

According to this configuration, since the second spring generates a primary urging force in advance, the urging force for urging the nozzle base is the urging force of the first spring, the primary urging force of the second spring, and the second urging force. Next will be the energizing force. By appropriately selecting the amount of the primary biasing force, the biasing force generated by the elastic deformation of the first spring and the elastic deformation of the second spring can be reduced. Therefore, it is possible to use a spring having a small spring constant as the first spring and the second spring, and even if an error occurs in registration of the lowermost point of the descent, the urging force of the nozzle base via the nozzle bracket against the nozzle tip is reduced. Fluctuations can be minimized.

[0012] In order to achieve the above object, in another configuration of the present invention, the transmission control means controls only the urging force of the first spring during the first press-fitting of the nozzle base into the nozzle tip. Transmitting the primary biasing force of the second spring in a second press-fitting stage, and further transmitting the secondary biasing force of the second spring in a subsequent third press-fitting stage. It is characterized by.

[0013] According to this configuration, following the urging force of the first spring in the first press-in stage, the primary urging force of the second spring added in the second press-in stage is set to be sufficiently large, so that the first spring is set. The urging force generated by the elastic deformation of the second spring and the elastic deformation of the second spring can be reduced. Therefore, it is possible to use a small spring constant spring for the first spring and the second spring,
Even when an error occurs in registration of the lowest point of descent, it is possible to minimize the fluctuation of the urging force of the nozzle base with respect to the nozzle tip via the nozzle bracket.

In order to achieve the above object, another configuration of the present invention is a nozzle tip mounting mechanism for urging a nozzle base and press-fitting the nozzle tip into a nozzle tip. A head holder movable in the press-fitting direction, a nozzle bracket movable along the guide and holding a nozzle base, and movably disposed between the head holder and the nozzle bracket, capable of abutting on the nozzle bracket An intermediate base having a convex portion, a regulating member provided on the head holder, for regulating movement of the intermediate base with respect to the nozzle bracket, and a regulating member disposed between the intermediate base and the nozzle bracket in accordance with an elastic deformation amount. A first spring for urging the nozzle bracket, and is disposed between the head holder and the intermediate base, and is elasticized in advance by a predetermined amount. A second spring that is shaped and generates a primary urging force, further elastically deforms from the predetermined amount, generates a secondary urging force according to the deformation amount, and urges the intermediate base. Receiving the primary urging force of the second spring by a regulating member in the first press-fitting step of the nozzle base with respect to the nozzle tip until the head holder moves in the press-fitting direction and the convex portion of the intermediate base comes into contact with the nozzle bracket; Only the urging force of the first spring is transmitted to the nozzle bracket, and the primary urging force of the second spring is additionally transmitted to the nozzle bracket in a second press-fitting step in which the projection comes into contact with the nozzle bracket. The secondary biasing force of the second spring may be additionally transmitted to the nozzle bracket at the third press-fitting stage moving in the press-fitting direction.

According to this configuration, when the convex portion of the intermediate base is not in contact with the nozzle bracket, the primary urging force generated by the second spring is applied to the regulating member in which the intermediate base is provided on the head holder. The intermediate base deforms only the first spring elastically by the movement of the head holder, and transmits only the urging force generated by the first spring to the nozzle bracket. Further, when the head holder moves and the convex portion comes in contact with the nozzle bracket, the regulating action of the regulating member disappears,
The primary biasing force of the second spring is additionally transmitted to the nozzle bracket via the convex portion of the intermediate base. Further, as the movement of the head holder progresses, elastic deformation of the second spring starts, and the secondary biasing force of the second spring is additionally transmitted to the nozzle bracket via the convex portion of the intermediate base. Therefore, by setting the primary biasing force of the second spring to be sufficiently large, the biasing force generated by the elastic deformation of the first spring and the elastic deformation of the second spring can be reduced, and the first spring and the second spring can be reduced. It is possible to use a spring with a small spring constant, and to minimize the fluctuation of the urging force of the nozzle base to the nozzle tip via the nozzle bracket even when an error occurs in registration of the lowest point of descent. .

According to another aspect of the present invention, there is provided a nozzle tip mounting mechanism for press-fitting a nozzle base by pressurizing a nozzle base to extend the nozzle tip in a press-fit direction of the nozzle tip. A guide member, a head holder having a stepped shaft that is movable along the guide member and has a large-diameter portion and a small-diameter portion, and is capable of moving along the guide member so that the shaft is inserted and holds the nozzle base. A nozzle bracket, a first sleeve movably disposed on a large diameter portion of the shaft and abuttable on the nozzle bracket, and a first sleeve movably disposed on a small diameter portion of the shaft and abutting on a step portion of the shaft. A second sleeve that is in contact with the first sleeve and a first spring that is disposed between the first sleeve and the nozzle bracket and that urges the nozzle bracket according to an amount of elastic deformation; A spring disposed between the second sleeve and the head holder and elastically deformed in advance by a predetermined amount to generate a primary urging force; A second spring that generates an urging force and urges the nozzle bracket via the first sleeve and the second sleeve, wherein the head holder moves in the press-fit direction and the first sleeve comes into contact with the nozzle bracket. In the first press-fitting step, the second press-fitting is such that the primary urging force of the second spring is received by the step portion of the shaft, and only the urging force of the first spring is transmitted to the nozzle bracket, and the first sleeve contacts the nozzle bracket. In the step, the primary urging force of the second spring is additionally transmitted to the nozzle bracket, and further, the head holder moves in the press-fitting direction, and The relative distance of second sleeve, characterized in that additional transmitting secondary bias force of the second spring to the nozzle bracket the third press-fit step of reduction.

According to this configuration, the second spring contacts the step portion of the shaft until the head holder moves together with the shaft in the nozzle tip press-fit direction and the first sleeve contacts the nozzle bracket. Suppress the primary biasing force. As a result, the first sleeve that moves together with the shaft elastically deforms only the first spring and transmits the biasing force to the nozzle bracket. Further, when the shaft moves and the first sleeve comes into contact with the nozzle bracket, and the regulating action of the step portion of the shaft disappears, the primary biasing force of the second spring is additionally transmitted to the nozzle bracket via the first and second sleeves. You. further,
When the shaft moves, the second spring starts elastically deforming, and the secondary biasing force of the second spring is additionally transmitted to the nozzle bracket. Therefore, by setting the primary biasing force of the second spring to be sufficiently large, the biasing force generated by the elastic deformation of the first spring and the elastic deformation of the second spring can be reduced, and the first spring and the second spring can be reduced. It is possible to use a spring with a small spring constant, and to minimize the fluctuation of the biasing force on the nozzle tip of the nozzle base via the nozzle bracket even if there is an error in registration of the lowest point of descent. it can.

According to another aspect of the present invention, the first spring and the second spring are compressed and deformed to generate an urging force.

According to this configuration, since the urging force generated by the elastic deformation of the spring can be directly used as the urging force for urging the nozzle bracket, the structure of the mechanism can be simplified.

According to another aspect of the present invention, a spring constant of the first spring and the second spring is smaller than a combined urging force generated by the first spring and the second spring. It is characterized in that the same urging force is smaller than the spring constant of a spring that generates the same amount of deformation.

According to this configuration, even if an error occurs in the registration of the lowermost point of descent, the spring force is small, so that the bias force generated by the error of the registered lowermost point of the descent is small, and the force applied through the nozzle bracket is small. Variations in the urging force of the nozzle base against the nozzle tip can be minimized.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are conceptual diagrams of the nozzle tip mounting mechanism according to the present embodiment, and show changes in the biasing state of each spring.

As shown in FIG. 1, the nozzle tip mounting mechanism 10 is supported by an XY arm (not shown) above a tip rack 14 for holding a plurality of nozzle tips 12 formed in a conical shape by resin or the like. , XY in a horizontal plane. The X-
It is also movable in the vertical direction (Z direction) along the guide rail 16 arranged on the Y arm in the vertical direction. The guide rail 16 has two sliding bodies 18a and 18b which slide independently, and a plate-shaped head holder 20 is fixed to the sliding body 18a located on the upper side. A cylindrical stepped shaft 22 having a small-diameter portion 22a at an upper portion and a large-diameter portion 22b at a lower portion is fixed to the head holder 20. A drive source such as a pulse motor (not shown) is connected to the slide body 18a via a drive belt or the like, and the head holder 20 and the shaft 22 can be moved in the Z direction by a predetermined amount under the control of a control unit (not shown). .

On the other hand, a plate-shaped nozzle bracket 24 is fixed to the slide body 18b, and a nozzle base 28 connected to a vacuum suction device (not shown) via a suction hose 26 is fixed to one end. The nozzle base 28 is formed of a metal such as stainless steel, for example, and has a tapered portion 28a that becomes thinner toward the lower end. A substantially central portion of the nozzle bracket 24 has a through hole 24a.
Is formed, and the large-diameter portion 22b of the shaft 22 is inserted therethrough. Then, from the lower end of the large diameter portion 22b, the stopper 3
0 is fixed so that the shaft 22 does not come out upward.

A cylindrical first sleeve 32 having a flange 32a projecting downward is loosely fitted to the large diameter portion 22b of the large diameter portion 22b of the shaft 22. A first spring 34 is inserted and arranged on the inner surface of the first sleeve 32. As the first spring 34, for example, a compression spring having a relatively small spring constant capable of generating a biasing force of about 300 gf (spring constant about 0.2 kgf / mm) by 1.5 mm compression is used.

On the other hand, a ring-shaped second sleeve 36 is also loosely disposed on the small diameter portion 22a of the shaft 22. The second spring 38 is inserted and arranged between the second sleeve 36 and the head holder 20 in a state where the second spring 38 is compressed by a predetermined amount. The second spring 38 has a compression of 3.5 mm, for example, about 1 kgf (spring constant about 0.3 mm).
Kgf / mm), which is a compression spring capable of generating a biasing force of 2 Kgf / mm). As shown in FIG. 1, the second sleeve 36 is a stepped portion 2 at the boundary between the small diameter portion 22 a and the large diameter portion 22 b of the shaft 22.
In a state in which it is in contact with 2c, it is inserted in a state in which an urging force of, for example, 2 kgf is generated as a primary urging force.

In the nozzle tip mounting mechanism 10 thus configured, in the initial state, the second sleeve 36 is urged toward the step 22c by the primary urging force of the second spring 38, and is pushed upward by the first spring 34. The first sleeve 32 is in contact with the first sleeve 32. Further, the nozzle bracket 24 is moved by the first spring 34 into the stopper 3.
0, and maintains a constant distance between the head holder 20 and the nozzle bracket 24.

When the nozzle tip mounting mechanism 10 moves over a predetermined nozzle tip 12 under the control of a control unit (not shown), it is driven by a pulse motor or the like.
The head holder 20 is lowered via the slide 18a.
Until the nozzle base 28 contacts the nozzle tip 12, the head holder 20 and the nozzle bracket 24 move in conjunction with each other, and the interval is maintained in the initial state.

Next, the procedure for registering the lowest descent point will be described. First, the nozzle tip 12 is moved directly above the nozzle tip 12 with reference to the nozzle tip mounting mechanism 10 by manual operation or step feed. Further, the head holder 20 and the nozzle bracket 24 are lowered by manual operation or step feed, and the tapered portion 28a of the nozzle base 28 is
Insert into After the tapered portion 28a comes into contact with the inner wall of the nozzle tip 12, the head holder 20
The position lowered by mm is registered as the mounting completion position, that is, the lowest point of descent. Therefore, the position in the Z direction at this time is registered in the control unit of the drive source such as the pulse motor for driving the sliding body 18a.

Next, in addition to FIGS. 1 to 3, while referring to a graph showing the relationship between the relative distance between the head holder and the nozzle bracket shown in FIG. 4 and the urging force for urging the nozzle head generated at that time. Next, the nozzle tip mounting operation of the nozzle tip mounting mechanism 10 will be described.

When a nozzle tip mounting instruction is issued from the dispensing apparatus main body (not shown), the XY arm is driven, and the nozzle tip mounting mechanism 1 is placed immediately above a predetermined nozzle tip 12.
Move 0. At this time, the predetermined nozzle tip 12 may be moved to a position directly below the nozzle base 28 by moving the tip rack 14 side. Subsequently, the sliding portion 18a is lowered by driving a pulse motor (not shown) to a lowermost lowering point registered in advance. At this time, if necessary, the sliding portion 18 until the nozzle base 28 comes into contact with the nozzle tip
The chip mounting time can be shortened by making the moving speed in the Z direction a faster than the moving speed after the contact.

When the tapered portion 28a of the nozzle base 28 comes into contact with the inner wall of the nozzle tip 12 and a predetermined contact friction occurs between the tapered portion 28a and the inner wall of the nozzle tip 12,
The lowering of the nozzle bracket 24 substantially stops, and the actual insertion operation starts. At this time, since the descent of the head holder 20 is continued, the shaft 22 and the first sleeve 32,
The second sleeve 36 is lowered, and the first spring 34 is
Are compressed as shown in FIG. A sensor for detecting the start of a change in the relative distance between the head holder 20 and the nozzle bracket 24 is provided on the sliding portions 18a, 18b and the like. (For example, when the tapered portion 28a contacts the upper end edge of the nozzle tip 12 or the tip rack 14). The change in the relative distance starts earlier than a predetermined position. In this case, it is determined that the mounting of the nozzle tip 12 has failed, and error processing, for example, the subsequent insertion operation is stopped and the operation is moved to the next nozzle tip position to perform the operation again, or an alarm is output.

When the compression of the first spring 34 is started at a predetermined position, as shown by a solid line in FIG. 4, a relative distance change of 1.5 mm (spring compression of 1.5 mm) causes about 300 g.
The urging force f is generated, and the nozzle base 28 is urged and pressed into the nozzle tip 12 via the nozzle bracket 24 (first press-fitting stage).

When the sliding portion 18a continues to descend, the flange 32a of the first sleeve 32 contacts the nozzle bracket 24. Until immediately before the contact between the flange 32a and the nozzle bracket 24, the primary biasing force of the second spring 38 is applied to the stepped portion 2 of the shaft 22 via the second sleeve 36.
2c, the primary urging force is not transmitted to the first sleeve or the like. However, the flange 32a
And at the same time the nozzle bracket 24 abuts, the contact between the step 22c and the second sleeve 36 is substantially released,
The primary biasing force of the second spring 38 is transmitted to the first sleeve 32 via the second sleeve 36. As a result, FIG.
As shown in the figure, the head holder 20 and the nozzle bracket 2
The urging force on the nozzle bracket 24 increases while the relative distance of No. 4 does not change. In the case of the present embodiment, at this time, the urging force is increased to about 2 kgf (second press-in stage).

When the sliding portion 18a continues to descend, the compression of the second spring 38 starts, and the second spring 3
8 generates a secondary biasing force. At this time, since the step 22c of the shaft 22 is completely separated from the second sleeve 36, the secondary biasing force of the second spring 38 is additionally transmitted to the nozzle bracket 24 via the second sleeve 36 and the first sleeve 32. Is done. Then, the secondary biasing force increases until the sliding portion 18a reaches the lowermost point of descent, and as shown in FIG. 4, a predetermined biasing force (about 3 kgf in the present embodiment).
Urges the nozzle bracket 24 (third press-fitting stage).
Note that, in the case of FIG.
When a primary biasing force is added during the press-fitting stage, the tapered portion 28
Although it has been described that the nozzle tip 12a and the nozzle tip 12 do not slip, actually, the slip slightly occurs, and the relative distance between the head holder 20 and the nozzle bracket 24 slightly changes.

As shown in FIG. 3, when the sliding portion 18a has descended to the registered lowermost point, the nozzle base 28 press-fits the nozzle tip 12 with a predetermined urging force. At this time, as described above, an error occurred in the registered lowermost point due to the standing state of the nozzle tip 12, the amount of descending of the sliding portion 18a was small, and the relative distance between the head holder and the nozzle bracket did not become smaller than a predetermined amount. In the case, for example, the relative distance is 4 mm
When only the first spring 38 contracts, the error of the biasing force generated by the second spring 38, which has been compressed in advance and generates the primary biasing force, having a small spring constant is about 300 gf. At this time, if a single spring generates a biasing force of 3 kgf with a compression of 5 mm as shown in the prior art (shown by a two-dot chain line in FIG. 4).
Is used, the error of the biasing force is about 650 gf, and when a spring having a weak spring constant and a spring having a strong spring constant are connected in series and used (indicated by a dashed line in FIG. 4), an error of the biasing force occurs about 800 gf. . Conversely, if the relative distance is 5
Even when the second spring is used, the error in the biasing force when the second spring is used is small. Therefore, in the configuration of the present embodiment, the error of the generated urging force with respect to the error of the lowest point of descent is much smaller than that of the conventional one.

As described above, by using a spring having a relatively small spring constant that generates a predetermined primary biasing force in advance, the influence of the error of the set lowermost point is minimized, and the extremely weak bias is applied. The nozzle tip can be stably mounted without urging the nozzle tip with an urging force or a strong urging force. That is, by appropriately selecting the urging force of the primary urging force of the second spring, the urging force generated by the elastic deformation of the first spring and the elastic deformation of the second spring can be reduced. Therefore, it is possible to use a spring having a small spring constant for the first spring and the second spring, and even when an error occurs in registration of the lowermost point of the descent, the urging force of the nozzle base via the nozzle bracket against the nozzle tip. Can be minimized.

After the nozzle tip is mounted, the sliding portion 18
a rises, the stopper 30 at the lower part of the shaft 22 contacts the nozzle bracket 24, the nozzle bracket 24 is pulled up, and the nozzle tip 12 is extracted from the tip rack 14. After that, under a predetermined control, it moves to aspirate a predetermined sample or reagent and performs a predetermined process. Also,
When removing the nozzle tip from the nozzle base, the nozzle tip mounting mechanism is moved to a predetermined chip disposal section, the upper end of the nozzle tip is hooked on a projection or the like, and the nozzle base is pulled up. At this time, as described above, since the nozzle tip is not mounted with an extremely strong urging force, an unnecessary load is not applied to the mechanism for pulling up the nozzle base even when the tip is removed.

In this embodiment, an example is described in which a compression spring having a relatively simple structure is used. However, a primary biasing force may be generated using a tension spring and a link mechanism. In addition, although the present embodiment has been described by taking as an example the mounting of a nozzle tip of a dispensing device, the present invention can be applied to other devices as long as the nozzle tip needs to be mounted with a constant urging force.

In this embodiment, the first sleeve and the second sleeve
Although the sleeve and the sleeve are arranged independently, a similar mechanism can be configured even if the first sleeve and the second sleeve are integrated. Furthermore, although an example in which a sleeve or a stepped shaft is used as means for suppressing the primary urging force has been described, a similar effect can be obtained as long as the mechanism can transmit the urging force in a stepwise manner.

Further, in this embodiment, an example is described in which the first sleeve, the second sleeve, the shaft, and the like are used as the urging force transmission control means, and the step portion of the shaft is used as the regulating member. As shown, instead of the first sleeve, the second sleeve, and the shaft, an intermediate base 44 movable between the head holder 40 and the nozzle bracket 42 having the nozzle base 42a is arranged.
And a first spring 46 between the nozzle bracket 42 and
May be arranged, and the second spring 48 may be arranged between the intermediate base 44 and the head holder 40. In this case, the transmission of the primary urging force of the second spring 48 is selectively restricted by the regulating member 50 provided on the head holder 40, and the primary spring 48 of the second spring 48 is regulated by the projection 52 provided on the intermediate base 44. Even when the urging force and the secondary urging force are transmitted to the nozzle bracket 42, the same effect as the configuration of FIG. 1 can be obtained.

[0042]

According to the present invention, since the second spring generates a primary urging force in advance, the urging force for urging the nozzle base is the urging force of the first spring and the primary urging force of the second spring. And the secondary bias. By appropriately selecting the amount of the primary biasing force, the biasing force generated by the elastic deformation of the first spring and the elastic deformation of the second spring can be reduced. Therefore, it is possible to use a spring having a small spring constant for the first spring and the second spring, and even if an error occurs in registration of the lowermost point of the descent, the urging force of the nozzle base at the nozzle tip with respect to the nozzle tip via the nozzle bracket. Fluctuations can be minimized.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of a nozzle tip mounting mechanism according to an embodiment of the present invention, which is a conceptual configuration diagram illustrating a state before a head holder descends.

FIG. 2 is a conceptual configuration diagram of a nozzle tip mounting mechanism according to an embodiment of the present invention, and is an explanatory diagram illustrating a state where a first spring is compressed.

FIG. 3 is a conceptual configuration diagram of a nozzle tip mounting mechanism according to an embodiment of the present invention, and is an explanatory diagram illustrating a state where a second spring is compressed.

FIG. 4 is an explanatory diagram illustrating a relationship between a relative distance between a head holder and a nozzle bracket and an urging force generated at that time to urge the nozzle bracket.

FIG. 5 is an explanatory diagram illustrating another configuration example of the nozzle tip mounting mechanism according to the embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional nozzle tip mounting mechanism.

[Explanation of symbols]

10 nozzle tip mounting mechanism, 12 nozzle tips, 1
4 chip racks, 16 guide rails, 18a, 18
b sliding body, 20 head holder, 22 shaft, 2
2a small diameter portion, 22b large diameter portion, 22c stepped portion, 24
Nozzle bracket, 28 nozzle base, 28a taper, 30 stopper, 32 first sleeve, 34 first
Spring, 36 second sleeve, 38 second spring.

Claims (6)

(57) [Claims] 1. A nozzle tip mounting mechanism for urging a nozzle base and press-fitting the nozzle tip into a nozzle tip, wherein: a nozzle bracket for holding the nozzle base; and a first spring for urging the nozzle bracket in accordance with an elastic deformation amount. A spring that is elastically deformed in advance by a predetermined amount and generates a primary urging force, and is further elastically deformed from the predetermined amount and generates a secondary urging force in accordance with the deformation amount to urge the nozzle bracket. Transmission control means for stepwise urging the nozzle base via the nozzle bracket based on the urging force of the first spring and the second spring in accordance with the state of press-fitting the nozzle base into the nozzle tip. And a nozzle tip mounting mechanism, comprising: 2. The mounting mechanism according to claim 1, wherein the transmission control means transmits only the urging force of the first spring to the nozzle bracket in a first press-fitting step of the nozzle base into the nozzle tip, and thereafter, The nozzle tip mounting mechanism further transmits a primary biasing force of the second spring in a second press-fitting step, and further transmits a secondary biasing force of the second spring in a subsequent third press-fitting step. . 3. A nozzle tip mounting mechanism for urging a nozzle base to press-fit into a nozzle tip, wherein the head holder is connected to a driving source and is movable in a press-fit direction along a guide, and is movable along the guide. A nozzle bracket that holds the nozzle base at, an intermediate base that is movably disposed between the head holder and the nozzle bracket, and that has a convex portion that can abut the nozzle bracket; A regulating member that regulates movement of the intermediate base with respect to the nozzle bracket; a first spring that is disposed between the intermediate base and the nozzle bracket and biases the nozzle bracket according to an amount of elastic deformation; A spring which is disposed between the springs and is elastically deformed in advance by a predetermined amount to generate a primary urging force; A second spring that is further elastically deformed from the predetermined amount and generates a secondary urging force in accordance with the amount of the deformation to urge the intermediate base, wherein the head holder moves in a press-fitting direction, and the intermediate base The first urging force of the second spring is received by the regulating member in the first press-fitting step of the nozzle base to the nozzle tip until the projection of the nozzle abuts on the nozzle bracket, and only the urging force of the first spring is transmitted to the nozzle bracket. Then, in the second press-fitting step in which the protrusion contacts the nozzle bracket,
A primary urging force of the spring is additionally transmitted to the nozzle bracket, and a secondary urging force of the second spring is additionally transmitted to the nozzle bracket in a third press-fitting step in which the head holder moves in the press-fitting direction. Nozzle tip mounting mechanism. 4. A nozzle tip mounting mechanism for urging a nozzle base to press-fit a nozzle tip into a nozzle tip, comprising: a guide member extending in the direction of press-fitting the nozzle tip; and a large-diameter portion movable along the guide member. A head holder having a stepped shaft composed of a small diameter portion and a stepped shaft, a nozzle bracket movable along the guide member, through which the shaft is inserted and holding a nozzle base, and movably disposed on a large diameter portion of the shaft. A first sleeve that can be brought into contact with the nozzle bracket, a second sleeve that is movably disposed on a small diameter portion of the shaft, and that comes into contact with a step portion of the shaft, between the first sleeve and the nozzle bracket. A first spring disposed to bias the nozzle bracket in accordance with the amount of elastic deformation; and a first spring disposed between the second sleeve and the head holder. A spring which is elastically deformed in advance by a predetermined amount and generates a primary urging force, and which is further elastically deformed from the predetermined amount and generates a secondary urging force in accordance with the amount of the deformation, via the first sleeve and the second sleeve. And a second spring for biasing the nozzle bracket. The primary biasing force of the second spring in a first press-fitting stage until the head holder moves in the press-fitting direction and the first sleeve contacts the nozzle bracket. At the step of the shaft, transmitting only the urging force of the first spring to the nozzle bracket, and applying the primary urging force of the second spring to the nozzle bracket at the second press-fitting stage where the first sleeve comes into contact with the nozzle bracket. In the third press-fitting step in which the head holder is moved in the press-fitting direction and the relative distance between the head holder and the second sleeve is reduced, additional transmission is performed. Nozzle tip attachment mechanism, characterized in that to add transmitting secondary bias force of the second spring to the nozzle bracket. 5. The mounting mechanism according to claim 1, wherein the first spring and the second spring compressively deform to generate an urging force. . 6. The mounting mechanism according to claim 1, wherein the spring constants of the first spring and the second spring are combined generated by the first spring and the second spring. A nozzle tip mounting mechanism characterized in that the biasing force equal to the biasing force is smaller than the spring constant of a spring that generates the same amount of deformation.