Patent Description:
The present invention relates to a member coupling mechanism used for coupling two members in an airtight manner. Such a member coupling mechanism is used, for example, when a sealing cap is mounted on an opening of a sample vaporization unit of a gas chromatograph to seal the opening in a state in which an O-ring is sandwiched between the sealing cap and the opening.

The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.

Generally, the gas chromatograph is provided with a sample vaporization unit for vaporizing the sample and feeding the vaporized sample into an analysis column. The sample vaporization unit is provided with a housing, and the housing has a space serving as a sample vaporization chamber therein. A sample inlet for injecting the sample into the sample vaporization chamber is provided at an upper portion of the housing. The lower portion of the sample vaporization chamber is connected to an analysis column to introduce a carrier gas from the upper portion of the sample vaporization chamber. The sample vaporization chamber is heated to a high temperature, and the liquid sample injected into the sample vaporization chamber is vaporized by the heat and fed to the analysis column by the carrier gas.

A cylindrical insert made of quartz-glass or the like is accommodated in the sample vaporization chamber in the housing. The sample injected through the sample inlet is vaporized inside the insert. Since the sample is vaporized inside the insert, the sample gas can be introduced into the analytical column without contacting the metallic inner wall of the sample vaporization chamber.

Since the insert comes into direct contact with the sample, the insert is a part that easily becomes dirty due to the adhesion of residues or the like after the sample vaporization. For this reason, the insert is detachably accommodated in the sample vaporization chamber so that the insert can be periodically replaced or cleaned. The upper surface of the housing is provided with an opening leading to the sample vaporization chamber, so that the insert can be inserted and removed through the opening. The opening of the housing is sealed by mounting a sealing cap.

A mechanism has been proposed to facilitate the attachment and detachment of a sealing cap to and from a housing (see Patent Document <NUM>). The proposed mechanism uses a coupling member to secure a sealing cap to a housing in a pressed state. The coupling member is provided with a main body for holding a sealing cap and an elastic deformation portion coupled to the main body, and a protrusion for engaging a step provided on the outer surface of the housing is provided at a tip end of the elastic deformation portion.

The step provided on the outer surface of the housing has a slope, and the coupling member is rotated so that the protrusion slides along the step with the protrusion of the coupling member engaged with the step to elastically deform the elastic deformation portion and generate an elastic force on the elastic deformation portion. The sealing cap held by the main body of the coupling member is pressed against the housing by the elastic force of the elastic deformation portion. With this, an O-ring sandwiched between the insert and the sealing cap is pressed to secure the air-tightness of the housing.

Patent Document <NUM>: International Publication No. <CIT>.

The protrusion of the coupling member is formed by press-fitting a pin made of a resin, such as, e.g., PBI (polybenzimidazole), into a hole of the elastic deformation portion in view of the slidability and the like. However, when the pin is press-fitted into the hole of the elastic deformation portion, the pin deforms and locally generates a portion with low intensity, which may reduce the durability of the coupling member. Therefore, it is also conceivable that the material of the pin is made of stainless steel or the like. However, metallic material, such as, e.g., stainless steel, has such a problem that the sliding property of the protrusion reduces due to wear with an increase in the number of times of use of the coupling member, and the force required for rotating the coupling member increases.

The preferred embodiments of the present invention have been developed in view of the above-mentioned and/or other problems in the related art. The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses.

The present invention has been made in view of the above-described problems, and an object of the present invention is to achieve both durability and slidability of a protrusion provided to a coupling member.

A member coupling mechanism according to the present invention, includes:.

In the member coupling mechanism according to the present invention, the protrusion provided to the coupling member is rotatable, and the protrusion is configured to move along the stepped portion while rotating when the coupling member is rotated in the circumferential direction of the member coupling portion. Therefore, the friction between the protrusion and the stepped portion is reduced, which ensures the slidability between the protrusion and the stepped portion when the coupling member is rotated. Since the slidability between the protrusion and the stepped portion is secured by the rotation of the protrusion, it is not necessary to form the protrusion by press-fitting the pin made of resin, and the durability of the protrusion can also be secured.

The preferred embodiments of the present invention are shown by way of example, and not limitation, in the accompanying figures.

In the following paragraphs, some preferred embodiments of the present invention will be described by way of example and not limitation. It should be understood based on this disclosure that various other modifications can be made by those skilled in the art based on these illustrated embodiments.

One example of a sample vaporization unit in a gas chromatograph to which a member coupling mechanism according to the present invention is applied will be described with reference to the attached drawings.

As shown in <FIG>, a housing <NUM> (first member) of a sample vaporization unit <NUM> has a prismatic shape in this example. Note that the shape of the housing <NUM> is not limited to a prismatic shape and may be a cylindrical shape or another shape.

The housing <NUM> is provided with a space 14a (see <FIG>, hereinafter referred to as "internal space 14a") for accommodating an insert <NUM> therein. The internal space 14a is a cylindrical hole leading from the upper surface of the housing <NUM> to the lower bottom outlet 2a. The housing <NUM> is made of a metallic material having good thermal conductivity.

In the housing <NUM>, a heater (not shown) is embedded to surround the internal space 14a. The insert <NUM> accommodated in the internal space 14a is heated by the heater. The insert <NUM> is a cylindrical member made of quartz-glass or the like.

The opening <NUM> of the housing <NUM> is sealed by the sealing cap <NUM> (second member). The sealing cap <NUM> is composed of a cylindrical sealing cap main body <NUM> and a disc-shape septum cover <NUM> attached to the top of the sealing cap main body <NUM>. A needle insertion portion <NUM> is provided to the septum cover <NUM>.

As shown in <FIG>, a septum <NUM> is arranged at the top of the sealing cap main body <NUM>. A septum cover <NUM> is mounted on the top of the sealing cap main body <NUM> so that the needle insertion portion <NUM> is located above the septum <NUM>.

The septum <NUM> is penetrable by a sample injecting needle inserted from the needle insertion portion <NUM> and closes the through-hole by the needle by its elasticity after the needle is pulled out. The septum <NUM> is made of an elastic material, such as, e.g., natural rubber and silicone rubber. The sample is discharged from the tip end of the needle penetrating the septum <NUM> to the side of the insert <NUM> via the through-hole <NUM> formed in the center of the sealing cap main body <NUM>.

The edge of the opening <NUM> on the upper surface of the housing <NUM> projects upward in an annular shape to form a cap mounting portion <NUM> (member coupling portion). The sealing cap <NUM> is secured to the cap mounting portion <NUM> by the coupling member <NUM>. A stepped portion <NUM> is provided at two symmetrical locations on the outer peripheral surface of the cap mounting portion <NUM>. The stepped portion <NUM> is inclined along the circumferential direction of the cap mounting portion <NUM> from the tip end side to the base end side of the cap mounting portion <NUM>. This stepped portion <NUM> has a side facing the base end side of the cap mounting portion <NUM>.

When attaching the sealing cap <NUM> to the housing <NUM>, the pin <NUM> of the coupling member <NUM> attached to the sealing cap <NUM> is engaged with the side of the stepped portion <NUM>. When the coupling member <NUM> is rotated in a plane (rotational plane) perpendicular to the axial direction of the cap mounting portion <NUM>, the pin <NUM> moves along the side of the stepped portion <NUM> and is displaced in the axial direction of the cap mounting portion <NUM>.

As shown in <FIG>, the coupling member <NUM> is provided with a ring-shaped coupling member main body 34a with a central hole and two elastic deformation portions 34b on one side of the coupling member main body 34a. When the side of the coupling member <NUM> on which the elastic deformation portion 34b is not provided is defined as a front side, and the side of the coupling member <NUM> on which the elastic deformation portion 34b is provided is defined as a rear side, the coupling member <NUM> is attached to the housing <NUM> so that the rear side faces the side of the housing <NUM>.

The elastic deformation portion 34b of the coupling member <NUM> is spaced apart from the coupling member main body 34a so as to be arcuate along the peripheral edge of the coupling member main body 34a. The base end of the elastic deformation portion 34b is integral with the coupling member main body 34a, but the tip end is free. That is, the elastic deformation portion 34b is a cantilever spring. The two elastic deformation portions 34b have the same shape. The coupling member main body 34a is provided with a lever <NUM> for holding and rotating the coupling member <NUM>.

A pin <NUM> is rotatably attached to the tip end of each elastic deformation portion 34b. The pin <NUM> has a first cylindrical portion 36a and a second cylindrical portion 36b, as shown in <FIG>. The first cylindrical portion 36a has an outer diameter d1 greater than the inner diameter of the hole formed at the tip end of the elastic deformation portion 34b. The second cylindrical portion 36b is connected to the first cylindrical portion 36a and has an outer diameter d2 smaller than the inner diameter of the hole formed at the tip end of the elastic deformation portion 34b. A groove 36c is provided at the end portion of the second cylindrical portion 36b opposite to the first cylindrical portion 36a. The pin <NUM> is fixed by a fastener <NUM> in a state of being fitted into the hole formed at the tip end of the elastic deformation portion 34b.

As shown in <FIG>, in the pin <NUM>, the second cylindrical portion 36b is inserted into the hole of the elastic deformation portion 34b from the inner side to penetrate the elastic deformation portion 34b so that the first cylindrical portion 36a protrudes to the inner side of the elastic deformation portion 34b to form a protrusion. An end of the second cylindrical portion 36b opposite to the first cylindrical portion 36a protrudes outside the elastic deformation portion 34b to expose the groove 36c, and a fastener <NUM> is attached to the groove 36c, so that the pin <NUM> does not come off from the hole of the elastic deformation portion 34b. The first cylindrical portion 36a of the side pin <NUM> forms a protrusion that protrudes inward from the elastic deformation portion 34b.

The material of the pin <NUM> is not particularly limited, but a high-hardness metallic material, such as, e.g., stainless steel, can be used. When such a high-hardness metallic material is used, the pin <NUM> is prevented from being broken when a high load is applied to the pin <NUM>, and the high durability of the coupling member <NUM> is obtained.

In a further preferred embodiment, at least the first cylindrical portion 36a of the pin <NUM> made of a high-hardness metallic material is subjected to a surface treatment, such as, e.g., a molybdenum disulfide coating, to reduce the frictional coefficient. This makes it possible to achieve both the durability of the coupling member <NUM> and the slidability of the pin <NUM> (protrusion).

As the fastener <NUM>, an E-ring as shown in <FIG> can be used.

In this example, the coupling member main body 34a and the elastic deformation portion 34b of the coupling member <NUM> are integrally formed by a production method, such as, e.g., a method of cutting from a metal block and an MIM (metal powder injection molding) method. Note that the coupling member main body 34a and the elastic deformation portion 34b may be formed as separate components and then connected to each other. In such a case, the materials of the coupling member main body 34a and the elastic deformation portion 34b need not be the same.

The coupling member main body 34a is movably engaged with the sealing cap main body <NUM> in the circumferential direction of the outer peripheral surface. That is, the coupling member main body 34a constitutes a second engaging portion that engages with the end portion of the sealing cap main body <NUM> that is a second member on the side of the housing <NUM>.

Specifically, as shown in <FIG>, the outer peripheral surface of the sealing cap main body <NUM> is provided with a horizontal groove 32a which is an annular recess provided in the circumferential direction. A C-type retaining ring <NUM> is fitted in the horizontal groove 32a. The C-type retaining ring <NUM> is a C-shaped metallic member having a notch in a portion thereof. The C-type retaining ring <NUM> has an inner diameter of the same size as that of the outer diameter of the portion of the sealing cap main body <NUM> where the horizontal groove 32a is provided and an outer diameter larger than that of the outer diameter of the portion of the sealing cap main body <NUM> where the horizontal groove 32a is not provided.

The inner diameter of the central hole of the coupling member main body 34a of the coupling member <NUM> is larger than the outer diameter of the sealing cap main body <NUM> with no horizontal groove 32a and smaller than the outer diameter of the C-type retaining ring <NUM>. The sealing cap main body <NUM> is fitted into the central hole of the coupling member main body 34a so that the C-type retaining ring <NUM> is located below the coupling member main body 34a.

Instead of the horizontal groove 32a and the C-type retaining ring <NUM> fitted in the groove 32a, a flange portion protruding from the outer peripheral surface in the circumferential direction of the sealing cap main body <NUM> may be integrally provided with the sealing cap main body <NUM>.

As shown in <FIG>, the stepped portion <NUM> includes a fitting recess 30a for fitting the pin <NUM>, the fitting recess 30a being provided on the upper end outer side of the cap mounting portion <NUM>, and the continuous sides 30b and 30c facing the base end of the cap mounting portion <NUM>. The sealing cap <NUM> is fixed to the cap mounting portion <NUM> as follows. That is, the sealing cap <NUM> is placed over the cap mounting portion <NUM> so that the pin <NUM> at the tip end of the elastic deformation portion 34b of the coupling member <NUM> fits in the recess 30a (the state shown in <FIG>). Then, the coupling member <NUM> is rotated in one direction (clockwise direction in <FIG>) so that the pin <NUM> moves along the sides 30b and 30c of the stepped portion <NUM> while rotating (the state of <FIG>).

Since the pin <NUM> is rotatable, the frictional force between the pin <NUM> and the sides 30b and 30c of the stepped portion <NUM> is reduced, and therefore, good slidability of the pin <NUM> relative to the stepped portion <NUM> is obtained. In a case where the pin <NUM> is press-fitted into the hole of the elastic deformation portion 34b and is not rotatable, the pin <NUM> slides on the sides 30b and 30c of the stepped portion <NUM> as the coupling member <NUM> rotates, and the pin <NUM> wears and the slidability and durability deteriorate.

The sides 30b and 30c of the stepped portion <NUM> are inclined with respect to the rotational plane of the coupling member <NUM> such that the pin <NUM> fitted in the recess 30a is displaced toward the base end of the cap mounting portion <NUM> as it moves clockwise along the outer peripheral surface of the cap mounting portion <NUM>. The inclination angles of the sides 30b and 30c are different, and the inclination angle of the side 30c is gentler than the inclination angle of the side 30b.

As shown in <FIG>, at the opening side of the internal space 14a of the housing <NUM>, an O-ring <NUM> (elastic sealing member) for sealing the clearance between the outer peripheral surface of the insert <NUM> and the inner wall surface of the internal space 14a is arranged. The O-ring <NUM> is made of, for example, fluororubber. In the vicinity of the opening <NUM> of the inner sidewall of the housing <NUM>, an annular base 28a inclined so that the inner diameter becomes smaller as it goes downward is provided, and the O-ring <NUM> is supported by the base 28a.

The sealing cap main body <NUM> has a recess for accommodating the upper end of the insert <NUM> on the lower surface thereof, and a lower end portion thereof is accommodated in the opening <NUM> so as to sandwich O-ring <NUM> with the base 28a. The annular lower end face of the sealing cap main body <NUM> is inclined such that the inner diameter increases toward the lower side, which is opposite to the base 28a.

When the sealing cap <NUM> is placed over the cap mounting portion <NUM> with the pin <NUM> of the coupling member <NUM> aligned with the recess 30a of the stepped portion <NUM>, the lower end of the sealing cap main body <NUM> comes into contact with the O-ring <NUM>. In this state, when the coupling member <NUM> is rotated so that the pin <NUM> moves along the side 30b and the side 30c of the stepped portion <NUM>, as shown in <FIG>, the side pin <NUM> is displaced toward the base end side of the cap mounting portion <NUM>, and the coupling member main body 34a presses the C-type retaining ring <NUM> downward.

As a result, the sealing cap main body <NUM> is pressed downward. The coupling member <NUM> presses the sealing cap main body <NUM> downward while rotating independently of the sealing cap main body <NUM> as the coupling member main body 34a engages with the C-type retaining ring <NUM>. Therefore, only the coupling member <NUM> can be rotated without rotating the sealing cap <NUM>.

The elastic deformation portion 34b of the coupling member <NUM> is elastically deformed to displace the position of the pin <NUM> in the axial direction of the cap mounting portion <NUM> relative to the coupling member main body 34a, and has a spring property that generates a restoring force corresponding to the displacement amount. When the coupling member <NUM> is rotated, and the pin <NUM> is moved to the end position of the side 30c of the stepped portion <NUM>, the elastic force of the elastic deformation portion 34b presses the sealing cap main body <NUM> toward the opening <NUM>. This deforms the O-ring <NUM> to such an extent that the ingress of gases into the gap between the inner wall of the internal space 14a and the outer peripheral surface of the insert <NUM> can be completely prevented.

The elastic deformation portion 34b of the coupling member <NUM> is designed to generate the elastic force required to deform the O-ring <NUM> by the required amount when the pin <NUM> reaches the end point position of the side 30c set as a position at a predetermined distance from the base end of the cap mounting portion <NUM>.

The example described above is merely one example of an embodiment of the member coupling mechanism according to the present invention. Embodiments of the member coupling mechanism according to the present invention are s follows.

The member coupling mechanism according to one aspect of the present invention includes:.

It may be configured such that the coupling member <NUM> is provided with a rotatable cylindrical protrusion 36a protruding toward an outer peripheral surface or an inner peripheral surface of the member coupling portion <NUM>, the protrusion 36a being configured to be engaged with the stepped portion <NUM> of the member coupling portion <NUM>. When the coupling member <NUM> is rotated in a circumferential direction of the member coupling portion <NUM>, the protrusion 36a moves along the stepped portion <NUM> while rotating to press the first member <NUM> and the second member <NUM> in an approaching direction to couple them.

In the first aspect of the embodiment according to the present invention, it may be configured such that the protrusion 36a is a part of a pin <NUM> inserted into a hole formed in the coupling member <NUM>.

In the first aspect of the present invention, it may be configured such that the pin <NUM> is made of stainless steel. This makes the protrusion more durable and improves the durability of the coupling member.

In the above-described case, it may be configured such that an outer peripheral surface of at least a part of the pin <NUM> forming the protrusion may be subjected to a surface treatment for reducing a frictional coefficient. This further improves the slidability of the protrusion.

Further, in the above-described first aspect of the present invention, it may be configured such that the pin <NUM> includes a first cylindrical portion 36a having an outer diameter larger than an inner diameter of the hole of the coupling member <NUM> and a second cylindrical portion 36b connected to the first cylindrical portion 36a, the second cylindrical portion 36b having an outer diameter smaller than the inner diameter of the hole of the coupling member <NUM>. In such a case, the first cylindrical portion 36a is inserted into the hole of the coupling member <NUM> so that the first cylindrical portion 36a forms a protrusion.

In the above-described case, it may be configured such that the second cylindrical portion 36b of the pin <NUM> penetrates through the hole of the coupling member <NUM>, and an end portion of the second cylindrical portion 36b opposite to the first cylindrical portion 36a protrudes from the hole, wherein a groove 36c is formed on an outer peripheral surface of the end portion protruding form the hole, and wherein a fastener <NUM> for preventing the second cylindrical portion 36b from coming off from the hole is attached to the pin <NUM> by being engaged with the groove 36c.

In a second aspect of the above-described embodiment, it may be configured such that the coupling member <NUM> includes.

Claim 1:
A member coupling mechanism comprising:
a first member including a cylindrical member coupling portion having an opening at a tip end face thereof, the member coupling portion including a stepped portion inclined along a circumferential direction from a tip end side of the member coupling portion toward a base end side thereof;
a second member configured to be coupled to the member coupling portion; and
a coupling member configured to be engaged with the stepped portion of the member coupling portion while holding an end portion of the second member on a side of the first member,
wherein the coupling member is provided with a rotatable cylindrical protrusion protruding toward an outer peripheral surface or an inner peripheral surface of the member coupling portion, the protrusion being configured to be engaged with the stepped portion of the member coupling portion, and
wherein when the connecting member is rotated in a circumferential direction of the member coupling portion, the protrusion moves along the stepped portion while rotating to press the first member and the second member in an approaching direction to couple them.