Patent Description:
For example, to a vehicle A using hydrogen as fuel, as show in <FIG>, at a hydrogen filling station is filled hydrogen gas after a filling nozzle <NUM> mounted on an end of a filling hose <NUM> and a vehicle side filling port <NUM> are connected with each other. The filling is controlled depending on the maximum using pressure of a hydrogen tank <NUM> mounted in the vehicle A. Here, when the vehicle A runs to pull the filling hose <NUM> while hydrogen gas is filled, a hydrogen filling apparatus is broken to inject a hydrogen gas, so that it becomes a dangerous condition. Then, a safety joint <NUM> for emergency releasing is mounted between a hydrogen filling apparatus <NUM> and the filling hose <NUM>, and when to the filling hose <NUM> is applied a tensile force more or equal to a predetermined value, the safety joint <NUM> separates to prevent the hydrogen filling apparatus <NUM> from being broken.

However, in case that the tensile force more or equal to the predetermined value is not applied to the filling hose <NUM>, when the filling hose <NUM> swings, there is a possibility that moment generated by the swinging of the filling hose <NUM> acts on a filling hose attached portion of a vehicle side member (plug) of the safety joint <NUM>, and the attached portion is broken to leak a hydrogen gas through the broken portion. Conventionally, any measures are not taken to prevent that the moment generated by the swinging of the filling hose <NUM> breaks a plug of the safety joint <NUM>.

As other conventional techniques are proposed safety joints for emergency releasing whose passages of the plug and the socket are orthogonal with each other (refer to <CIT> gazette for example), but a safety joint capable of preventing the safety joint from being broken due to the moment generated by the swinging of the filling hose <NUM> has not been proposed yet. Reference is made to <CIT> and <CIT>. <CIT> discloses a cable that limits the movement of the coupling between the plug and the socket by flexibly tying the socket to the hydrogen filling apparatus. Swinging of the hose in the proximity of the coupling is, however, not prevented.

The present invention has been made in consideration of the above problems in the prior art, and the object thereof is to provide a safety joint capable of preventing the safety joint from being broken due to the moment generated by the swinging of the filling hose and surely separating a hydrogen filling apparatus side member from the vehicle side member when the tensile force more or equal to the predetermined value is applied to the filling hose to prevent the hydrogen filling apparatus from being broken.

A safety joint <NUM> according to the present invention is characterized by including a plug (<NUM>: vehicle side member) with a cylindrical shape in which a passage (1A: in-plug passage) is formed, a socket (<NUM>) in which a passage (21A: in-socket passage) continuing to the passage (1A) in the plug (<NUM>) is formed, and a shut off valve mounted on the passage (21A: in-socket passage) in the socket (<NUM>), the shut off valve opening when the plug (<NUM>) being inserted into the socket (<NUM>) and closing when the plug (<NUM>) being disconnected therefrom, wherein central axes of the passages of the plug (<NUM>) and the socket (<NUM>) do not form a straight line (but those are orthogonal with each other for instance), a filling hose (<NUM>) is connected to the plug (<NUM>), and hose guides (<NUM>, 70A) for limiting movement of the filling hose (<NUM>) at a position separated from the plug (<NUM>). It is preferable that the safety joint (<NUM>) according to the present invention is arranged near a base portion of the filling hose (<NUM>) communicating with a filling nozzle and near a weighing machine (hydrogen filling apparatus).

The hose guides (<NUM>, 70A) include outer cylinders (<NUM>, 71A), elastic members (<NUM>, 72A) for surrounding the filling hose (<NUM>), elastic member accommodating portions (<NUM>, 73A) accommodating the elastic members (<NUM>, 72A) in a hollow portion, and lid portions (<NUM>, 74A) engaging with the elastic member accommodating portions (<NUM>, 73A) to close the hollow portion, and inner diameter sizes (ϕ1, ϕ1A) of the outer cylinders (<NUM>, 71A) are larger than the maximum diameter (D2) of the plug (<NUM>). It is preferable that the outer cylinder (70A) is fixed by an outer cylinder fixing portion (<NUM>), a projection (73AT) projecting outward in a radial direction of the hose guide (70A) is formed on an end portion (a lower end portion in <FIG>) of the elastic member accommodating portion (73A) of the hose guide (70A), and a channel (75B) capable of accommodating the projection (73AT) is formed on an inner peripheral surface of the outer cylinder fixing portion (<NUM>).

In the present invention, it is preferable that the safety joint further includes a cover (<NUM>) for protecting a valve rod mounted on one of the plug (<NUM>) and the socket (<NUM>). Then, it is preferable that a longitudinal size of the cover (<NUM>) is longer than that of the valve rod (plug side rod <NUM>, for example) and the cover (<NUM>) completely covers the valve rod. In this case, it is preferable that inner diameter sizes (ϕ1, ϕ1A) of the outer cylinders (<NUM>, 71A) of the hose guides (<NUM>, 70A) are larger than the maximum diameter (D1) of the cover (<NUM>).

In the present invention, it is preferable that the cover (<NUM>) is configured to surround one portion of a member on a side that the valve rod (<NUM>) is not mounted and capable of being attached to the plug (<NUM>) and the socket (<NUM>). Here, "capable of being attached" defines that, in an emergency such that a vehicle suddenly moves when hydrogen is filled, the cover (<NUM>) does not prevent the separation between the plug (<NUM>) and the socket (<NUM>) but the cover (<NUM>) is not separated from the member on which the valve rod (<NUM>) is mounted (plug <NUM>, for example) even when the plug (<NUM>) and the socket (<NUM>) are separated from each other.

In addition, in the present invention, it is preferable that the plug (<NUM>) includes a depressurizer (<NUM>) including a main body portion (<NUM>) made of metal, a depressurizing communication hole (31B) communicating with a hydrogen gas passage (31A) in the main body portion(<NUM>), a depressurizing plug (<NUM>) made of metal, the depressurizing plug (<NUM>) capable of being inserted into the depressurizing communication hole (31B), and tapered portions (a pin tapered portion 32B of the depressurizing plug <NUM> and a tapered portion 31BB of the depressurizing communication hole 31B) formed on the depressurizing communication hole (31B) and the depressurizing plug (<NUM>) respectively, the tapered portions having complemental shapes with each other. In this case, it is preferable that a relief circuit (31C) for discharging filled fluid (hydrogen gas, for example) is formed, the relief circuit (31C) communicates with the depressurizing communication hole (31B), and an outlet of the relief circuit (31C) is formed at a position separated from an upper region of the depressurizing plug (<NUM>).

In the depressurizer (<NUM>), it is preferable that length (L) of a hydrogen passage side end portion (32A: pin end portion) of the depressurizing plug (<NUM>) and a length (HL) of a hydrogen passage side end portion (31BA: small diameter portion) of the depressurizing communication hole (31B) are long.

With the present invention with the above construction, the filling hose (<NUM>) is held by the small diameter portions (portions with inner diameter ϕ) of the hose guides (<NUM>, 70A) and the plug (<NUM>) side end portion of the safety joint (<NUM>). A swinging of the hose (<NUM>) is perfectly shut at a portion held by the small diameter portions (portions with inner diameter ϕ) of the hose guides (<NUM>, 70A) and is not transmitted to the plug (<NUM>) side of the safety joint (<NUM>). Therefore, moment generated by the swinging of the hose (<NUM>) do not act on the plug (<NUM>) of the safety joint (<NUM>), and it is prevented that the plug (<NUM>) is broken.

In addition, in the safety joint (<NUM>) according to the present invention, when the inner diameters (ϕ1, ϕ1A) of the outer cylinders (<NUM>, 71A) of the hose guides (<NUM>, 70A) are larger than an outer diameter (D2: maximum diameter) of the plug (<NUM>) of the safety joint (<NUM>), even if a tensile force more or equal to a predetermined value is applied to the filling hose (<NUM>) due to a sudden movement of the vehicle during hydrogen filling for instance to separate the socket (<NUM>) and the plug (<NUM>) from each other, the separated plug (<NUM>) passes through the insides of the outer cylinders (<NUM>, 71A) of the hose guides (<NUM>, 70A). Therefore, a tensile force applied to the filling hose (<NUM>) does not act on the hydrogen filling apparatus, it is prevented that the hydrogen filling apparatus is fallen and breakage thereof due to the fall.

In the present invention, with the hose guides (<NUM>, 70A) including the outer cylinders (<NUM>, 71A) whose inner diameter sizes (ϕ1, ϕ1A) are larger than the maximum diameter (D2) of the plug (<NUM>), the elastic members (<NUM>, 72A) for surrounding the filling hose (<NUM>), the elastic member accommodating portions (<NUM>,73A) for accommodating the elastic members (<NUM>, 72A) in the hollow portion, and the lid portions (<NUM>, 74A) engaging with the elastic member accommodating portions (<NUM>, 73A) to close the hollow portion, when a tensile force more or equal to the predetermined value is applied to the filling hose (<NUM>) to separate the socket (<NUM>) and the plug (<NUM>) from each other, not only the filling hose (<NUM>) and the plug (<NUM>) but also the elastic member accommodating portions (<NUM>, 73A), the lid portions (<NUM>, 74A), the elastic members (<NUM>, 72A) of the hose guides (<NUM>, 70A) can pass through areas inside the outer cylinders (<NUM>,71A) in a radial direction of the hose guides (<NUM>, 70A). Then, the plug (<NUM>) surely moves on the vehicle side from the hose guides (<NUM>, 70A), the tensile force toward the vehicle is not applied to the socket (<NUM>) and the hydrogen filling apparatus, and it is surely prevented that the hydrogen filling apparatus is fallen or broken.

Here, when the outer cylinder (71A) is fixed by the outer cylinder fixing portion (<NUM>), on the end portion (lower end portion in <FIG>) of the elastic member accommodating portion (73A) of the hose guide (70A) is formed the projection (73AT) projecting outward in a radial direction of the hose guide (70A), and on the inner peripheral surface of the outer cylinder fixing portion (<NUM>) is formed the channel (75B) capable of accommodating the projection (73AT), the projection (73AT) fits into the channel (75B), which prevents the outer cylinder fixing portion (<NUM>) and the elastic member accommodating portion (73A) from rotating relative to each other. Then, even if a twist occurs on the filling hose (<NUM>), at the portion where the filling hose (<NUM>) is held by the elastic member (72A) is suppressed rotation of the filling hose (<NUM>), so that it is prevented that the rotating force due to the twist acts on the plug (<NUM>) to break it.

In the present invention, with the cover (<NUM>) for surrounding the valve rod (plug side rod <NUM>, for example), even if the plug (<NUM>) and the socket (<NUM>) of the safety joint (<NUM>) are separated from each other in an emergency, and the member (plug <NUM>, for example) on the valve rod (<NUM>) side falls or collides with the hydrogen filling apparatus, vehicle and the like, the valve rod (<NUM>) is protected by the cover (<NUM>), so that any impact due to the falling and the collision of the valve rod (<NUM>) side member are not added to the valve rod (<NUM>), which prevents the valve rod (<NUM>) from being broken.

In addition, in the present invention, with the depressurizer (<NUM>) mounted on the plug (<NUM>), when the plug (<NUM>) and the socket (<NUM>) are separated from each other, high pressure hydrogen gas in the filling hose (<NUM>) can be discharged at small flow rate outside the filling hose (<NUM>) (outside the depressurizer <NUM>). Therefore, it is prevented that the high pressure hydrogen gas rapidly injects, and the filling hose (<NUM>) unexpectedly moves around due to the rapid injection of the hydrogen gas.

Hereinafter, embodiments of the present invention will be explained with reference to the attached drawings. In <FIG> and <FIG>, a whole safety joint (pipe joint for emergency releasing) according to the embodiment is shown as the numeral <NUM>. The safety joint <NUM> includes a plug <NUM> with a cylindrical shape and a socket <NUM>. When the plug <NUM> and the socket <NUM> are connected with each other, shutoff valves in the plug <NUM> and the socket <NUM> open to communicate an in-plug passage 1A (<FIG>) with an in-socket passage 21A (<FIG>). In <FIG> and <FIG>, the plug <NUM> and the socket <NUM> are connected with each other, but when the plug <NUM> is separated from the socket <NUM>, the shutoff valves therein close. The plug <NUM> is basically connected to a vehicle side (lower side in <FIG> and <FIG>), the socket <NUM> is basically communicated with a hydrogen filling apparatus (or a dispenser, a weighing machine) side, and the socket <NUM> extends from the front of the paper surface to the back thereof in <FIG> and <FIG>. However, it is possible to arrange the plug <NUM> to the hydrogen filling apparatus side and arrange the socket <NUM> to the vehicle side. In <FIG> and <FIG>, the socket <NUM> is mounted through an attachment member <NUM> and a base member <NUM> to the hydrogen filling apparatus not shown.

For example, as shown in <FIG>, central axes of the passage in the plug <NUM> (in-plug passage 1A) and the passage in the socket <NUM> (in-socket passage 21A) are orthogonal with each other. Constructions and action effects of the plug <NUM> and the socket <NUM> will be explained in detail with reference to <FIG>. In addition, in <FIG>, to the central axes of the in-plug passage and the in-socket passage are attached C1 and C2 respectively.

In <FIG> and <FIG>, a cover <NUM> is mounted to protect a plug side rod <NUM> (valve rod: refer to <FIG>) mounted on the plug <NUM>. The longitudinal size of the cover <NUM> is longer than that of the plug side rod <NUM>, and the cover <NUM> extends along the central axis C1 of the in-plug passage and thoroughly surrounds the plug side rod <NUM> in the plug <NUM>. In addition, the cover <NUM> surrounds a connected portion of the plug <NUM> and the socket <NUM>. The cover <NUM> is mounted to protect the plug side rod <NUM> when the plug <NUM> and the socket <NUM> are separated from each other, so that the cover <NUM> is attached to the plug <NUM> side. However, the cover cannot prevent the separation between the plug <NUM> and the socket <NUM>. In addition, the cover <NUM> can be omitted.

In <FIG> and <FIG>, on a vehicle side end portion (lower end portion in <FIG> and <FIG>) of the plug <NUM> surrounded by the cover <NUM> is mounted a depressurizer <NUM>. The depressurizer <NUM> is not surrounded by the cover <NUM>, and is connected to the plug <NUM> side. As shown in <FIG>, to the depressurizer <NUM> is connected a vehicle side filling hose <NUM> thorough a concaved portion 31F. In addition, in <FIG> and <FIG>, the filling hose <NUM> is expressed with a virtual line. Construction and function of the depressurizer <NUM> will be explained in detail with reference to <FIG>. However, the depressurizer <NUM> can be omitted, in such a case, the vehicle side filling hose <NUM> is directly connect to the plug <NUM>.

On the vehicle side of the plug <NUM> is connected the filling hose <NUM> through the depressurizer <NUM>, and on an end portion of the filling hose <NUM> opposite to the plug <NUM> side is arranged a filling nozzle not shown. As described above, the socket <NUM> is connected to the hydrogen filling apparatus side, and the safety joint <NUM> is arranged near the hydrogen filling apparatus and a base portion of the filling hose <NUM>.

In a direction that the filling hose <NUM> extends (lower side in <FIG> and <FIG>), at a position separated from the plug <NUM> is arranged a hose guide <NUM> for limiting movement (swinging) of the filling hose <NUM>. In <FIG>, the hose guide <NUM> is provided with an outer cylinder <NUM>, an elastic member <NUM> for surrounding the filling hose <NUM>, an elastic member accommodating portion <NUM> for accommodating the elastic member <NUM> in a hollow portion, and a lid portion <NUM> for closing the hollow portion of the elastic member accommodating portion <NUM>. The outer cylinder <NUM> with a cylindrical shape accommodates the elastic member <NUM>, the elastic member accommodating portion <NUM>, and the lid portion <NUM> (members constructing the hose guide <NUM>), and the outer cylinder <NUM> is attached through an attachment member <NUM> to the base member <NUM>. Here, the inner diameter size ϕ1 of the outer cylinder <NUM> is slightly larger than the maximum diameter D1 of the cover <NUM> for surrounding the plug <NUM>. In addition, when the cover <NUM> is omitted, it is sufficient to set the inner diameter size ϕ1 slightly larger than the maximum diameter D2 (D2<D1) of the plug <NUM>.

In <FIG>, the elastic member <NUM> with a columnar shape has a hole (small diameter portion) whose inner diameter is ϕ on a central portion in a radial direction, into the hole is inserted the filling hose <NUM>, and as a material of the elastic member <NUM> is selected an elastic member such as rubber. The inner diameter ϕ of the small diameter portion (when the elastic member <NUM> is accommodated in the accommodating portion <NUM>) is set slightly larger than the outer diameter of the filling hose <NUM>, so that the elastic member <NUM> surrounds the filling hose <NUM> while tightening it to support it. Although not clearly shown in figures, in a radial direction of the elastic member <NUM> is formed a cut surface (corresponding to numeral 72AB in <FIG>), and opening the elastic member <NUM> through the cut surface allows the elastic member <NUM> to be arranged to surround (wind around) the filling hose <NUM>.

In <FIG>, the elastic member accommodating portion <NUM> with a cylindrical shape is provided with a hollow portion for accommodating the elastic member <NUM>, and a supporting portion <NUM> for supporting the elastic member <NUM> in a vertically direction in <FIG>. A safety joint side (upper side in <FIG>) end portion of the inner peripheral surface of the elastic member accommodating portion <NUM> projects radially inward, on an inner periphery in a radial direction of the projecting portion is formed a female screw 73F, and the female screw 73F engages with a male screw <NUM> of an outer peripheral surface of the lid portion <NUM>. Then, the maximum outer diameter of the elastic member accommodating portion <NUM> is set smaller than the inner diameter size ϕ1 of the outer cylinder <NUM>. The lid portion <NUM> is formed in a hollow cylindrical shape (section of the lid portion is annular) including a hollow portion <NUM>, and on an outer peripheral surface is formed the male screw <NUM>. In <FIG>, numerals <NUM> and <NUM> express thrust washers.

When the filling hose <NUM> is mounted to the safety joint <NUM>, the outer cylinder <NUM> of the hose guide <NUM> has been attached through the base member <NUM> to the hydrogen filling apparatus, so that the filling hose <NUM> pass through the outer cylinder <NUM>, the elastic member accommodating portion <NUM>, the thrust washers <NUM>, <NUM>, the hollow portion of the lid portion <NUM> of the hose guide <NUM>, and the safety joint <NUM> side end portion of the filling hose <NUM> is connected to the depressurizer <NUM>. When the depressurizer <NUM> is omitted, the end portion of the filling hose <NUM> is directly connected to the plug <NUM>. Next, the elastic member <NUM> is arranged between the thrust washers <NUM>, <NUM>, the elastic member <NUM> is opened from the cut surface, and the elastic member <NUM> is arranged to surround the filling hose <NUM>.

Next, the male screw <NUM> of the lid portion <NUM> is screwed to the female screw 73F of the elastic member accommodating portion <NUM>, and the lid portion <NUM> is rotated in a direction compressing the elastic member <NUM>. By the compression of the lid portion <NUM>, elastically repulsive force of the elastic member <NUM> tightens the filling hose <NUM>. And, the elastic member <NUM> is accommodated and fixed in the elastic member accommodating portion <NUM>. In addition, after the elastic member <NUM> is accommodated in the elastic member accommodating portion <NUM>, and the elastic member accommodating portion <NUM>, the thrust washers <NUM>, <NUM> and the lid portion <NUM> are accommodated in the outer cylinder <NUM>, and the filling hose <NUM> can be connected to the safety joint <NUM> side end portion.

In <FIG> and <FIG> showing a condition that the plug <NUM> and the socket <NUM> are connected with each other, the filling hose <NUM> is connected to the plug <NUM> side, and extends through the hose guide <NUM> on the vehicle side. At that time, as described above, the filling hose <NUM> is held or fixed by the elastic member <NUM> while being tightened thereby. When the filling hose <NUM> swings, the swings thereof are perfectly shut at a portion supported by the elastic member <NUM> of the hose guide <NUM>, and do not transmit on the side of the plug <NUM> of the safety joint <NUM>. Therefore, swings of the filling hose <NUM> do not act on the plug <NUM> of the safety joint <NUM>, and it is prevented that the plug <NUM> or the depressurizer <NUM> is broken.

As described above, the inner diameter ϕ1 of the outer cylinder <NUM> of the hose guide <NUM> is set larger than the maximum outer diameter D1 of the cover <NUM> of the plug <NUM> of the safety joint <NUM> (<FIG>). In addition, the maximum outer diameter of the elastic member accommodating portion <NUM> of the hose guide <NUM> is set smaller than the inner diameter size ϕ1 of the outer cylinder <NUM>. For example, when the vehicle rapidly moves while hydrogen is filled thereto and a tensile force (arrow F) more or equal to a predetermined value is applied to the filling hose <NUM>, as shown in <FIG>, the socket <NUM> and the plug <NUM> of the safety joint <NUM> are separated from each other.

When the plug <NUM> is separated from the socket <NUM>, as shown in <FIG>, the filling hose <NUM> enters into an area inside the outer cylinder <NUM> of the hose guide <NUM> in a radial direction thereof, passes through the outer cylinder <NUM>, and moves toward the vehicle side (lower side in <FIG>). At that time, members accommodated in the outer cylinder <NUM> of the hose guide <NUM> (the elastic member <NUM>, the elastic member accommodating portion <NUM>, the lid portion <NUM>, and the thrust washers <NUM>, <NUM>) do not stay at a position inside the outer cylinder <NUM> of the hose guide <NUM>, and move toward the vehicle side from the outer cylinder <NUM> together with the plug <NUM> and the filling hose <NUM>. The cover <NUM> surrounding the plug <NUM> passes through the area radially inside the outer cylinder <NUM> of the hose guide <NUM> together with the plug <NUM>.

Therefore, when a tensile force more or equal to a predetermined value acts on the filling hose <NUM> to separate the plug <NUM> and the socket <NUM> from each other, the plug <NUM> will not be caught in the hose guide <NUM>, and the hydrogen filling apparatus will not be pulled on the vehicle side, which prevents the hydrogen filling apparatus from being fallen or broken. In other words, the hose guide <NUM> has a function of shutting the swinging of the filling hose <NUM> and not transmitting a moment generated by the swinging to the plug <NUM>, and a function of allowing the plug <NUM> (including the cover <NUM>) to pass through an area inside the outer cylinder <NUM> in a radial direction thereof, and preventing a tensile force from acting on the hydrogen filling apparatus when the socket <NUM> and the plug <NUM> are separated from each other.

In the embodiment shown in the figures, the depressurizer <NUM> can be configured to be accommodated in the hollow portion <NUM> inside the lid portion <NUM> of the hose guide <NUM> in a radial direction thereof. With this construction, when the plug <NUM> is separated from the socket <NUM>, even if the depressurizer <NUM> collides to the hollow portion <NUM> of the lid portion <NUM>, an impact generated by the collision is absorbed by the elastic member <NUM>. When the depressurizer <NUM> is omitted, it is possible that the lid portion <NUM> accommodates the plug <NUM> in the hollow portion <NUM>. Further, it is possible that the lid portion <NUM> does not accommodate the depressurizer <NUM> and the plug <NUM> in the hollow portion <NUM>.

Next, the plug <NUM> and the socket <NUM> of the safety joint <NUM> will be explained with reference to <FIG>. The cover <NUM> explained with reference to <FIG> is shown by doted lines in <FIG> and <FIG>, but is deleted in <FIG> and <FIG> to avoid complexities in illustrations. In <FIG>, the plug <NUM> shaped like a cylinder as a whole body includes a plug main body <NUM> and a plug side rod case <NUM>. To a central portion (a vertically central portion at a right end of the plug main body <NUM> in <FIG>) on the vehicle side (right side in <FIG>, a side apart from the socket <NUM> side) end portion of the plug main body <NUM> is mounted a hydrogen gas supply port 1B. At a vertically central portion of the plug main body <NUM> is formed an in-plug passage 1A, and on the in-plug passage 1A is formed a plug side valve element accommodating portion 1C. In the in-plug passage 1A, a passage in the plug side rod case <NUM> communicates through a passage in the plug side valve element accommodating portion 1C with the hydrogen gas supply port 1B.

In the in-plug passage 1A is accommodated a plug side rod <NUM>, and on an end portion on the side separated from the socket <NUM> of the plug side rod <NUM> (right side in <FIG>) is mounted a plug side valve element <NUM>. On a vehicle side (right side in <FIG>) of the plug side valve element <NUM> is arranged a plug side spring <NUM>, which energizes the plug side valve element <NUM> toward the socket <NUM> side (left side in <FIG>). The plug side valve element <NUM> and a valve seat 1F configure a plug side shutoff valve <NUM>, and the plug side shutoff valve <NUM> has a function of shutting/opening the plug side passage 1A. An end portion on the opposite side (left side in <FIG>) of the valve element <NUM> configures a locking portion 2A.

In <FIG>, on the outside in a radial direction of the hydrogen gas supply port 1B of the plug main body <NUM> is formed a flange portion 1D. The flange portion 1D connects the depressurizer <NUM> (refer to <FIG> and <FIG>) by a conventional technique. On the other hand, when the plug <NUM> and the socket <NUM> are connected with each other, the surface of the flange portion 1D on the side opposite to the surface connected to the depressurizer <NUM> abuts on a plug accommodating housing <NUM> of the socket <NUM>. On an outer peripheral surface of the plug main body <NUM> is formed a connecting channel 1E, and to the connecting channel 1E is fitted a connecting ball <NUM> for connecting the plug <NUM> and the socket <NUM> with each other.

The plug side rod case <NUM> projects from the plug main body <NUM> toward the socket <NUM> side (left side in <FIG>), and is shaped in a form of a hollow cylinder whose socket <NUM> side end portion is closed, and in an inner space of the plug side rod case <NUM> is accommodated the plug side rod <NUM>. In the outer periphery of the plug side rod case <NUM>, at a position corresponding to a lower portion of a socket side rod <NUM> is formed an opening 3A for passage connection. When the plug <NUM> and the socket <NUM> are connected with each other, the plug side rod case <NUM> is inserted into of an opening portion 21C of the socket <NUM> (the socket main body <NUM>), and the in-plug passage 1A and an in-socket passage 21A are communicated with each other through the opening 3A.

In <FIG>, near the socket <NUM> side end portion of the plug side rod case <NUM> is formed a locking ball channel 3B, and in the locking ball channel 3B are held locking balls <NUM>. As shown in <FIG>, by the tapered portion of the locking portion 2A are pressed the locking balls <NUM> radially outward. But, under the condition shown in <FIG>, by an inner wall surface of the opening portion 21C of the socket <NUM>, the locking balls <NUM> do not move radially outward the plug side rod case <NUM>. On the other hand, as shown in <FIG>, under a condition that the plug <NUM> and the socket <NUM> are separated from each other, there is no member that prevents the locking balls <NUM>, which are pressed radially outward the plug side rod case <NUM>, from moving, and the locking balls <NUM> position radially outward the plug side rod case <NUM> from the condition shown in <FIG>.

In <FIG>, the socket <NUM> shaped like a cylinder as a whole body has the socket main body <NUM> and the plug accommodating housing <NUM>. On a horizontally central portion of a hydrogen filling apparatus side (upper side in <FIG>) end portion of the socket main body <NUM> is formed a hydrogen gas introducing port 21B. On a horizontally central portion of the socket main body <NUM> shown in <FIG> is formed the in-socket passage 21A extending in the vertical direction, and in a socket side valve element accommodating portion 21D (enlarged portion) formed on the in-socket passage 21A is accommodated a socket side valve element <NUM>. The in-socket passage 21A communicates from the hydrogen gas introducing port 21B through the socket side valve element accommodating portion 21D and a hollow portion of the socket side rod <NUM>, with the opening portion 21C of the socket main body <NUM>. In the opening portion 21C of the socket <NUM>, an end portion apart from the plug <NUM> of the opening portion 21C (left side in <FIG>) is opened. Then, on the inner periphery of the opening portion 21C are mounted O-rings SS1, SS2.

To the socket side valve element <NUM> is connected the socket side rod <NUM>. On the side of the hydrogen gas introducing port 21B (upper side in <FIG>) of the socket side valve element <NUM> is arranged a socket side spring <NUM>, and the socket side spring <NUM> energizes the socket side valve element <NUM> toward a valve seat 21E (lower side in <FIG>). The valve element <NUM> and the valve seat 21E configure a socket side shutoff valve <NUM>, which has a function of shutting/opening the socket side passage 21A. A hydrogen gas fed to the valve element accommodating portion 21D inflows through the openings 22A formed on the socket side rod <NUM> to the hollow portion of the socket side rod <NUM>. Then, the hollow portion of the socket side rod <NUM> configures a portion of the in-socket passage 21A.

The plug accommodating housing <NUM> whose end portions are opened projects from the socket main body <NUM> toward the plug <NUM> (right side in <FIG>). On the inner peripheral surface of the plug accommodating housing <NUM> are formed at-connection arrangement portions 26A and an at-disconnection accommodating channel 26B. On the at-connection arrangement portions 26A are arranged the connecting balls <NUM> when the plug <NUM> and the socket <NUM> are connected with each other, and in the at-disconnection accommodating channel 26B are accommodated the connecting balls <NUM> moved from the at-connection arrangement portions 26A when from the socket <NUM> is disconnected the plug <NUM>. The horizontal (lateral in <FIG>) position of the at-connection arrangement portions 26A corresponds to that of the plug side connecting channel 1E of the plug main body <NUM>. In addition, on the side of the socket <NUM> (left side in <FIG>) of the at-connection arrangement portions 26A is formed a projection α projecting from the at-connection arrangement portions 26A inwardly in a radial direction of the plug <NUM>.

When hydrogen gas is filled, the plug <NUM> is inserted into the plug accommodating housing <NUM>, and by the connecting balls <NUM> and the connecting spring <NUM> are integrally connected the plug <NUM> and the socket <NUM> with each other. As shown in <FIG>, when the plug <NUM> and the socket <NUM> are connected with each other, the spring holder <NUM> to which the connecting spring <NUM> is attached positions in a gap between the inner peripheral surface of the plug accommodating housing <NUM> and the outer peripheral surface of the plug main body <NUM>. The connecting balls <NUM> are fitted into connecting ball holes 42A formed on the spring holder <NUM>, and engage with the plug side connecting channel 1E of the plug main body <NUM>. At this time, on the socket <NUM> side of the connecting balls <NUM> (left side in <FIG>) positions the projection α, and in the radially outward direction of the connecting balls <NUM> position the at-connection arrangement portions 26A. The spring holder <NUM> engages with the plug <NUM> through the connecting balls <NUM> and the plug side connecting channel 1E. Then, when the plug <NUM> and the socket <NUM> are connected with each other, the plug <NUM> and the socket <NUM> are integrated with each other so as to hold the spring holder <NUM> and the connecting balls <NUM> in between.

In <FIG>, when a force pulling out the plug <NUM> (a tensile force acting on the filling hose <NUM>: a force moving the plug <NUM> rightward in <FIG>) is applied, through the connecting balls <NUM>, the spring holder <NUM> and the connecting spring <NUM> try to move in a direction apart from the socket <NUM> (right side in <FIG>). Unless more or equal to predetermined magnitude of force for pulling out the plug <NUM> is applied thereto, even if to the connecting balls <NUM> are applied the forces shown as the allows M in <FIG>, the forces are weakened by the elastically repulsive force by the connecting spring <NUM>, and a condition that connecting balls <NUM> are fitted into the plug side connecting channel 1E is maintained, which does not release the connection between the plug <NUM> and the socket <NUM>. On the other hand, when more or equal to predetermined magnitude of force for pulling out the plug <NUM> is applied thereto, the connecting balls <NUM> disengaged from the plug side connecting channel 1E and move in the arrow M directions, and as show in <FIG>, the connecting balls <NUM> are fitted into the at-disconnection accommodating channel 26B (<FIG>) of the plug accommodating housing <NUM>. Then, the plug <NUM> is disconnected from the socket <NUM>, resulting in a disjoint condition shown in <FIG> and <FIG>. Here, the predetermined value (boundary value that the joint between the plug <NUM> and the socket <NUM> is released) is determined based on specifications of the hydrogen filling apparatus, the filling hose and the like, and based on the predetermined value are designed the plug <NUM>, the socket <NUM> and the like.

As shown in <FIG>, under a condition the plug <NUM> and the socket <NUM> are connected with each other, the lower end portion of the hollow socket side rod <NUM> abuts on the plug side rod case <NUM>, so that the socket side rod <NUM> positions, against the elastically repulsive force of the socket side spring <NUM>, on an upper portion in <FIG>, and the socket side shutoff valve <NUM> opens. In addition, as shown in <FIG>, the plug side rod <NUM> that cannot move leftward from the locking balls <NUM> separates, against the elastically repulsive force of the plug side spring <NUM>, the plug side valve element <NUM> from the plug side valve seat 1F. As a result, the plug side shutoff valve <NUM> opens. When both of the socket side shutoff valve <NUM> in the socket <NUM> and the plug side shutoff valve <NUM> in the plug <NUM> become open, the in-socket passage 21A (the hydrogen gas introducing port 21B, the socket side valve element accommodating portion 21D, the hollow portion of the socket side rod <NUM> and the opening portion 21C of the socket <NUM>) and the in-plug passage 1A (the hollow portion of the plug side rod case <NUM>, the plug side valve element accommodating portion 1C) are communicated with each other, and from the side of the hydrogen filling apparatus (weighing machine) to the side of the vehicle flows hydrogen gas.

When a tensile force more or equal to a predetermined magnitude is applied to the filling hose so as to detach the connecting balls <NUM> (connecting members) from the plug side connecting channel 1E, the plug <NUM> and the socket <NUM> are disconnected from each other. When the plug <NUM> and the socket <NUM> are disconnected from each other, as shown in <FIG>, the plug side rod case <NUM> of the plug <NUM> is detached from the opening portion 21C of the socket <NUM> (socket main body <NUM>), and the socket side valve element <NUM> moves downward in <FIG> by an elastically repulsive force of the socket side spring <NUM>. As a result, the socket side valve element <NUM> seats on the socket side valve seat 21E, and the socket side shutoff valve <NUM> shuts the in-socket passage 21A. In addition, as shown in <FIG>, when the locking balls <NUM> moves outwardly radially from the plug side rod case <NUM> in the locking ball channel 3B, the plug side rod <NUM> moves leftward from the locking balls <NUM> by the elastically repulsive force of the plug side spring <NUM>. As a result, the plug side valve element <NUM> seats on the plug side valve seat 1F, and the plug side shutoff valve <NUM> shuts the in-plug passage 1A. Since the socket side shutoff valve <NUM> and the plug side shutoff valve <NUM> close the in-socket passage 21A and the in-plug passage 1A respectively, hydrogen gas does not leak from vehicle side and weighing machine side.

As explained with reference to <FIG> and <FIG>, the cover <NUM> (expressed with dashed lines in <FIG> and <FIG>) is mounted to protect the plug side rod <NUM>. As shown in <FIG>, when the plug <NUM> and the socket <NUM> are connected with each other, the cover <NUM> surrounds the plug <NUM> and the plug side rod <NUM>. On the other hand, as shown in <FIG>, when the plug <NUM> and the socket <NUM> are disconnected from each other, the cover <NUM> attached to the plug <NUM> side separates from the socket <NUM> also. The cover <NUM> has a size capable of perfectly covering the plug side rod <NUM> in an axial direction thereof. Therefore, even if the plug <NUM> and the socket <NUM> are separated from each other, and the plug <NUM> falls and collides with the hydrogen filling apparatus or the vehicle, to the plug side rod <NUM> protected by the cover <NUM> is not directly added an impact, and breakage of the plug side rod <NUM> is prevented.

In the socket main body <NUM> of the safety joint <NUM> shown in <FIG>, the end portion opposite to the plug <NUM> side (left side in <FIG>) of the opening portion 21C in which the plug side rod case <NUM> is inserted opens. But, in the opening portion 21C, the end portion opposite to the plug <NUM> side (left side in <FIG>) can be closed to be a blind hole. In this case, the O-ring SS2 (<FIG>) is not required.

Next, with reference to <FIG> will be explained a hose guide in a mode different from the hose guide shown in <FIG>. A hose guide <NUM> shown in <FIG> shuts swinging of the filling hose <NUM> to prevent moment by the swinging from acting on the plug <NUM> of the safety joint <NUM>. And, even if the socket <NUM> and the plug <NUM> are disconnected from each other, the plug <NUM> can pass through inside of the outer cylinder <NUM> of the hose guide <NUM>, so that it is prevented that the hydrogen filling apparatus falls. A hose guide indicated by the numeral 70A in <FIG> also has a function of preventing that a portion of the hose on the safety joint <NUM> side from the hose guide 70A rotates when a twist occurs in the filling hose <NUM> (<FIG>).

The hose guide 70A has, as same as the hose guide <NUM> shown in <FIG>, an outer cylinder 71A, an elastic member 72A surrounding the filling hose <NUM>, an elastic member accommodating portion 73A accommodating the elastic member 72A in a hollow portion, and a lid portion 74A for closing the hollow portion of the elastic member accommodating portion 73A, and further includes an outer cylinder fixing portion <NUM> and a nut <NUM> for tightening the outer cylinder fixing portion <NUM> downward (<FIG>). In <FIG>, the outer cylinder 71A with a hollow cylindrical shape accommodates the elastic member 72A, the elastic member accommodating portion 73A, and the lid portion 74A. On a lower end of the outer cylinder 71A is mounted a flange 71AA projecting radially outward over an entire circumference. In addition, in the outer peripheral surface of the outer cylinder 71A, from an upper end portion to near of a lower end portion is formed a male screw 71AF screwed to a female screw of the nut <NUM>. Here, the inner diameter size ϕ1A of the outer cylinder 71A is set lager than the maximum diameter D1 (<FIG>) of the cover <NUM> for covering the plug <NUM>.

As same as the explanation with reference to <FIG>, the elastic member accommodating portion 73A has a hollow portion for accommodating the elastic member 72A, a supporting portion 73AH for supporting the elastic member 72A in a vertical direction (<FIG>), and a female screw 73AF on an inner peripheral surface. However, on the lower end portion (<FIG>) of the elastic member accommodating portion 73A is formed a projection 73AT projecting radially outward. The projection 73AT can be formed at one spot in a radial direction, but plurality of projections 73AT can be formed at plural spots.

The outer cylinder fixing portion <NUM> is arranged on an outer periphery of the lower end portion of the outer cylinder 71A, on an inner peripheral surface of the outer cylinder fixing portion <NUM> is formed a channel 75A, and into the channel 75A can be accommodated the flange 71AA of the outer cylinder 71A. In order to insert the flange 71AA into the channel 75A and facilitate the attachment, although not clearly shown in figures, it is preferable that the outer cylinder fixing portion <NUM> is divided into two parts in a radial direction, or configured like a nest. On the inner peripheral surface of the outer cylinder fixing portion <NUM> is formed a channel 75B capable of accommodating the projection 73AT of the elastic member accommodating portion 73A, and the channel 75B extends in a longitudinal direction of a filling hose not shown, that is, in a vertical direction in <FIG> and opens at an end portion of the outer cylinder fixing portion <NUM>. Although not clearly shown in figures, the outer cylinder fixing portion <NUM> is fixed to the hydrogen filling apparatus side by a known method, and the outer cylinder fixing portion <NUM> is attached to the base member <NUM> shown in <FIG> and <FIG>, for example.

The elastic member 72A and the lid portion 74A are the same as the elastic member <NUM> and the lid portion <NUM> shown in <FIG> respectively. The numeral 72AB shown in <FIG> indicates a cut surface formed in a radial direction of the elastic member 72A, opening from the cut surface 72AB causes the elastic member 72A to be arranged to surround the filling hose <NUM> or to wind around the filling hose <NUM>. Although not clearly shown in <FIG>, on the elastic member <NUM> shown in <FIG> is mounted the same cut surface as the cut surface 72AB. In <FIG>, the numerals <NUM> and <NUM> indicate thrust washers.

When the filling hose <NUM> is mounted on the safety joint <NUM>, the flange 71AA of the outer cylinder 71A is inserted into the channel 75A of the outer cylinder fixing portion <NUM>; the nut <NUM> is screwed to the male screw 71AF of the outer peripheral surface of the outer cylinder 71A; the outer cylinder fixing portion <NUM> is sandwiched between the nut <NUM> and the flange 71AA of the outer cylinder 71A; and the outer cylinder 71A is fixed to the outer cylinder fixing portion <NUM>. The outer cylinder fixing portion <NUM> to which the outer cylinder 71A is fixed is fixed through the base member <NUM> (<FIG> and <FIG>) to the hydrogen filling apparatus (not shown) side for example. Next, the filling hose <NUM> is passed through the elastic member accommodating portion 73A, the thrust washers <NUM>, <NUM>, the lid portion 74A, the outer cylinder 71A, the outer cylinder fixing portion <NUM>, the hollow portion of the nut <NUM>, and the safety joint <NUM> side end portion of the filling hose <NUM> is connected to the depressurizer <NUM>. However, when the depressurizer <NUM> is omitted, the safety joint <NUM> side end portion of the filling hose <NUM> is connected to the plug <NUM>.

Then, the elastic member 72A is opened from the cut surface 72AB to surround the filling hose <NUM>. And, the lid portion 74A, the thrust washer <NUM>, the elastic member 72A, the thrust washer <NUM>, the elastic member accommodating portion 73A are accommodated in the hollow portion of the outer cylinder 71A. When the elastic member accommodating portion 73A is accommodated, a position of the projection 73AT in a radial direction is matched with a position of the channel 75B of the outer cylinder fixing portion <NUM> in a radial direction, and the elastic member accommodating portion 73A is inserted from an opened portion on a lower portion in <FIG> into the channel 75B. Then, the male screw 74AM of the lid portion 74A is screwed to the female screw 73AF of the elastic member accommodating portion 73A, the lid portion 74A rotates to compress the elastic member 72A in a vertical direction of <FIG>, and the elastic member 72A is fixed in the elastic member accommodating portion 73A.

In the hose guide 70A configured as shown in <FIG>, the projection 73AT of the elastic member accommodating portion 73A and the channel 75B of the outer cylinder fixing portion <NUM> action as a key and a key groove respectively, so that the elastic member accommodating portion 73A can move in a vertical direction of <FIG> but cannot rotate relative to the outer cylinder fixing portion <NUM>. Here, in the same manner as explained with reference to <FIG>, to the filling hose <NUM> is added tightening force from the elastic member 72A. Therefore, even if a twist occurs in the filling hose <NUM>, rotation of the filling hose <NUM> is suppressed by a portion where the filling hose <NUM> held by the elastic member 72A. Then, the twist of the filling hose <NUM> is shut at the portion held by the elastic member 72A, and is not transmitted to the plug <NUM> side of the safety joint <NUM>, so that it is prevented that the rotation of the filling hose <NUM> breaks the depressurizer <NUM> or the plug <NUM>. Other construction and action effect of the hose guide 70A shown in <FIG> are the same as those of the hose guide <NUM> shown in <FIG>.

Next, the depressurizer <NUM> will be explained with reference to <FIG>. The depressurizer <NUM> is attached to the plug <NUM> of the safety joint <NUM>, and has a function of depressurizing high pressure hydrogen gas in an area on the vehicle side from the plug <NUM> of the filling hose <NUM> when the plug <NUM> and the socket <NUM> are separated from each other. In addition, hydrogen gas in an area on the hydrogen filling apparatus side from the socket <NUM> is depressurized by a depressurizing mechanism not shown on the hydrogen filling apparatus side.

In <FIG>, the depressurizer <NUM> has a metal depressurizer main body portion <NUM> with a nearly rectangular parallelepiped shape and a metal depressurizing plug <NUM>, and the depressurizing plug <NUM> is configured to engage with (be screwed to) a depressurizing communication hole 31B of the main body portion <NUM>. On a right side of the main body portion <NUM> is formed a concaved portion 31F, and to the concaved portion 31F is connected the vehicle side filling hose <NUM>. Although not clearly shown, an end portion 31E on a left side of the main body portion <NUM> is connected to the plug <NUM> of the safety joint <NUM>. On a central portion in a vertical direction of the main body portion <NUM> is formed a hydrogen gas passage 31A, and the hydrogen gas passage 31A communicates through the end portion 31E with the in-plug passage 1A on the plug <NUM> side and communicates through the concaved portion 31F with the filling hose <NUM>.

In <FIG>, the depressurizing communication hole 31B communicating from an upper surface <NUM> with the hydrogen gas passage 31A extends in a vertical direction, and with the depressurizing communication hole 31B communicates a relief circuit 31C (<FIG>). A cross sectional area of the relief circuit 31C is set small to be enough to add a sufficient pressure loss to a flowing hydrogen gas. Into the depressurizing communication hole 31B is fitted the depressurizing plug <NUM>, and as shown in <FIG>, engagement of the depressurizing plug <NUM> and the depressurizing communication hole 31B shuts the relief circuit 31C from the hydrogen gas passage 31A.

The depressurizing communication hole 31B has a small diameter portion 31BA communicating with the hydrogen gas passage 31A, a tapered portion 31BB, the first middle diameter portion 31BC, the second middle diameter portion 31BD, and a female screw portion 31BE communicating with the upper surface <NUM>. On the other hand, the depressurizing plug <NUM> has a pin end portion 32A with a minimum diameter in a lower end portion, a pin tapered portion 32B, a pin middle diameter portion 32C, a male screw portion 32D forming a male screw on an outer periphery. When the depressurizing plug <NUM> is fitted into the depressurizing communication hole 31B, the pin end portion 32A of the depressurizing plug <NUM> is inserted into the small diameter portion 31BA of the depressurizing communication hole 31B.

As shown in <FIG>, the pin tapered portion 32B of the depressurizing plug <NUM> and the tapered portion 31BB of the depressurizing communication hole 31B are complementary shapes with each other, and the pin tapered portion 32B contacts the tapered portion 31BB. Here, the depressurizing plug <NUM> and the main body portion <NUM> are made of metal, so that a portion where the pin tapered portion 32B and the tapered portion 31BB contact with each other configures a so-called "metal seal". Between the pin middle diameter portion 32C of the depressurizing plug <NUM> and the second middle diameter portion 31BD of the pressurizing communication hole 31B is arranged an O-ring <NUM>, and the O-ring <NUM> prevents high pressure hydrogen gas from injecting upward in <FIG> and <FIG> from a gap between the depressurizing plug <NUM> and the depressurizing communication hole 31B when the depressurizing plug <NUM> sufficiently rises against the depressurizing communication hole 31B (in a condition that engagement between the depressurizing plug <NUM> and the main body portion <NUM> is released: refer to <FIG>). On the depressurizing communication hole 31B is formed the female screw portion 31BE, and to the female screw portion 31BE is screwed a male screw formed on the outer periphery of the male screw portion 32D. In addition, on an upper surface of the depressurizing plug <NUM> is formed a hexagon socket 32E (plug hexagon socket), and a hexagonal rod spanner not shown is inserted into the plug hexagon socket 32E to be rotated when the depressurizing plug <NUM> is attached to/detached from the depressurizing communication hole 31B.

As shown in <FIG>, in an area near a boundary between the tapered portion 31BB and the first middle diameter portion 31BC, the depressurizing communication hole 31B communicates with the relief circuit 31C. As shown in <FIG> and <FIG>, in a condition that the depressurizing plug <NUM> is tightened to the depressurizing communication hole 31B, the pin tapered portion 32B and the tapered portion 31BB of the depressurizing communication hole 31B contact with each other to configure the metal seal, so that high pressure hydrogen gas flowing in the hydrogen gas passage 31A is completely shut by the metal seal and does not flow into the relief circuit 31C. On the other hand, when the plug <NUM> and the socket <NUM> are separated from each other, the depressurizing plug <NUM> is rotated in a depressurizing direction by the hexagonal rod spanner for example, the engagement between the female screw portion 31BE of the depressurizing communication hole 31B and the male screw portion 32D of the depressurizing plug <NUM> is released, the pin tapered portion 32B and the tapered portion 31BB of the depressurizing communication hole 31B are separated from each other, and the metal seal is released.

A condition that the metal seal is released is shown in <FIG>. A diameter size d1 of the pin end portion 32A is set smaller than the inner diameter d2 of the small diameter portion 31BA of the depressurizing communication hole 31B (d1<d2), between an outer periphery of the pin end portion 32A and an inner periphery of the small diameter portion 31BA of the depressurizing communication hole 31B is formed an annular gap whose cross sectional area is (π/<NUM>)(d2<NUM>-d1<NUM>). When the depressurization shown in <FIG> is performed, high pressure hydrogen gas filled in the hydrogen gas passage 31A inflows through the annular gap (working as an orifice) into the relief circuit 31C and passes through the relief circuit 31C to outflow from the depressurizer <NUM> as shown by the arrow O. At that time, the pressure of the hydrogen gas decreases when the hydrogen gas passes through the annular gap and the relief circuit 31C, so that it is prevented that the hydrogen gas suddenly injects from the relief circuit 31C. Then, it is prevented the filling hose <NUM> moves around. Here, a hydrogen gas outlet of the relief circuit 31C is mounted at a position apart from the plug hexagon socket 32E (above the depressurizing plug <NUM>). Then, even if sparks generate by contacts between the hexagonal rod spanner and the plug hexagon socket 32E when the hexagonal rod spanner is inserted into the plug hexagon socket 32E to be rotated, a possibility that the hydrogen gas catches fire due to the sparks becomes extremely low, and safety thereof improves.

In <FIG>, as shown in <FIG> for example, in a condition the depressurizing plug <NUM> is tightened to the depressurizing communication hole 31B, a length L of the pin end portion 32A (vertical length in <FIG>) and a length HL of the small diameter portion 31BA of the depressurizing communication hole 31B are relatively long, and a length LW of the pin end portion 32A inserted into the small diameter portion 31BA of the depressurizing communication hole 31B is relatively long also. Therefore, even if the hexagonal rod spanner is excessively rotated in the plug hexagon socket 32E, the pin end portion 32A will not be completely separated from the small diameter portion 31BA of the depressurizing communication hole 31B, a condition that the hydrogen gas passes through the annular gap between the small diameter portion 31BA and the pin end portion 32A (cross sectional area is (π/<NUM>)(d2<NUM>-d1<NUM>)) is maintained, and pressure of the hydrogen gas can be decreased due to the pressure loss.

Although not shown in figures, in the depressurizer <NUM>, the length L of a hydrogen passage side end portion (pin end portion 32A) of the depressurizing plug <NUM> can be set shorter, on the upper surface <NUM> of the main body portion <NUM> can be mounted a lock pin inserted hole, into the lock pin inserted hole can be inserted the a lock pin for suppressing the rotation of the hexagonal rod spanner.

Claim 1:
A safety joint (<NUM>) comprising a plug (<NUM>) with a cylindrical shape in which a passage is formed, a socket (<NUM>) in which a passage continuing to the passage in the plug (<NUM>) is formed, and a shut off valve mounted on the passage in the socket (<NUM>), the shut off valve opening when the plug (<NUM>) being inserted into the socket (<NUM>) and closing when the plug (<NUM>) being disconnected therefrom,
wherein central axes of the passages of the plug (<NUM>) and the socket (<NUM>) do not form a straight line,
the safety joint (<NUM>) further comprising:
a filling hose (<NUM>) connected to the plug (<NUM>), and
a hose guide (<NUM>, 70A) for limiting movement of the filling hose (<NUM>) at a position separated from the plug (<NUM>), wherein the socket (<NUM>) is rigidly mounted to a common base member (<NUM>), wherein the safety joint (<NUM>) comprises the base member (<NUM>),
wherein the hose guide (<NUM>) is provided with an outer cylinder (<NUM>) and wherein the outer cylinder (<NUM>) is attached through an attachment member (<NUM>) to the base member (<NUM>), wherein the hose guide (<NUM>, 70A) further includes an elastic member (<NUM>, 72A) for surrounding the filling hose (<NUM>), an elastic member accommodating portion (<NUM>, 73A) accommodating the elastic member (<NUM>, 72A) in a hollow portion, and a lid portion (<NUM>) engaging with the elastic member accommodating portion (<NUM>, 73A) to close the hollow portion, and an inner diameter size of the outer cylinder (<NUM>, 71A) is larger than a maximum diameter of the plug (<NUM>).