Spear tube for beer keg

Abstract: A spear tube (1) comprises a body connected with a keg neck interface (3) of the beer keg (2). A gas valve (13), a down tube (5) and a beer valve (4) installed in the down tube are fittingly connected to the body. A stopper (20) prevents the spear tube (1) from popping out from the beer keg during detaching operation. A stopper portion (23) of the stopper (20) is formed protruding in the obliquely upward direction to penetrate a side hole (4c) of the body and has a cross-section of a predetermined curvature shape. Therefore, the stopper functions to prevent the popping-out of the spear tube and provides improved durability.

Description: BACKGROUND OF THE INVENTION The present invention relates to improvements in a spear tube for a beer keg, and more particularly to a spear tube which is arranged to avoid popping-out thereof when detached from the beer keg. In order to pour beer from a beer keg into a mug or jug through a dispenser having a dispense head attached to a keg neck interface of the beer keg, the internal pressure in the beer keg is increased by supplying carbon dioxide gas into the beer keg so as to push out the beer. A dispense head of the dispenser is connected to a spear tube screwed to the keg neck interface of the beer keg, so as to communicate the dispenser with the inside of the beer keg. In order to exchange a seal ring and/or a gas valve of recycled beer keg for maintenance in a factory, it is necessary to detach the spear tube from the keg neck interface of the beer keg. When the spear.tube is detached, the spear tube pops out of the beer keg by the residual gas pressure in the beer keg and it is dangerous for an operator. It is necessary to sufficiently open the gas valve of a spear tube and to release the residual gas from the beer keg so as to avoid the popping out the spear tube. In this practical maintenance in a factory, it is not easy to check as to whether the gas in the beer keg is sufficient released. Therefore, it is necessary that the spear tube is provided with any safety device for preventing the popping out during the detaching thereof. Japanese Patent Provisional Publication No. 7-232799 discloses a spear tube having a stopper for preventing the popping out thereof. This stopper of the disclosed spear tube is arranged to have a stopper portion extending in the obliquely upward direction so as to penetrate a hole formed at a side wall of the body. The Japanese publication discloses a spear tube according to the pre-characterising part of claim 1. However, since the stopper portion is made of flat and straight plate and has not enough bending strength, it is not sufficient to restrain popping out of a spear tube in view of function and durability. Secondly, the stopper portion is V-shaped and beer remains in the upward part of the stopper portion. The remaining beer is difficult to clean up and causes decay of beer and growth of fungus. EP-A-0 761 555, which forms part of the state of the art only by virtue of Article (54)3 EPC, discloses a stopper portion with a cross-section having a predetermined curvature to enhance rigidity. It is an object of the present invention to provide an improved spear tube which performs the function of a stopper while ensuring sufficient durability. The present invention provides a spear tube as set forth in claim 1. In the accompanying drawings: Fig. 1 is a cross sectional view of an essential part of a spear tube of an embodiment according to the present invention; Fig. 2A is a side view, partially in cross section, of a body of the spear tube of Fig. 1; Fig. 2B is a bottom view of the body; Fig. 3A is a plane view of a retaining disc of the spear tube of Fig. 1; Fig. 3B is a cross sectional view taken on line X-X of Fig. 3A; Figs. 4A, 4B, 4C and 4D are a cross-sectional side view, a plan view, an expanded plan view and a partially enlarged view of a stopper of the spear tube of Fig. 1, respectively; and Figs. 5A, 5B, 5C and 5D are a cross-sectional side view, a plan view, an expanded plan view and a partially enlarged view of another example of the stopper of the spear tube, respectively. Referring to Figs. 1 to 5D, there is shown an embodiment of a spear tube 1 for a beer keg 2 in accordance with the present invention. The spear tube 1 comprises a body 4 whose external thread portion 4a is detachably screwed with an internal thread portion 3a of a keg neck interface 3 of a beer keg 2. A gas valve 13 for opening and closing a passage for carbon dioxide gas is disposed in the body 4. A down tube 5 is pushed upwardly by a coil spring 6 and its upper flange portion 11 is in contact with the gas valve 13. A beer valve 14 is disposed in the down tube 5 and is pushed by a coil spring 15 to be in contact with a lower and inner peripheral portion of the gas valve 13 functioning as a valve seat. A stopper 20 made of an elastic member is engaged with the down tube 5 and extends between the coil spring 6 and the body 4. A stopper portion 23 of the stopper 20 protrudes in the outward and upward direction so as to penetrate a hole 4c of the body 4. The stopper portion 23 is disposed such that a tip portion 23c thereof is generally in contact with a lower portion of the keg neck interface 3 in the beer keg 2. The hole 4c of the body 4, from which the stopper portion 23 protrudes, is formed such that the lower periphery of the hole 4c corresponds to the cross-sectional shape of the stopper portion 23, as shown in Figs. 2A and 2B. That is, the hole 4c is formed into a pentagonal shape including a V-shaped lower periphery and has a vertical dimension T which is equal to or greater than a stroke of the down tube 5 during the beer pouring. By this correspondence of the lower periphery of the hole 4c of the stopper portion 23, it becomes possible to prevent the deformation of the stopper portion 23 caused by the impact of colliding the stopper portion 23 to the lower periphery of the hole 4c when the spear tube 1 is detached from the beer keg 2 due to the residual gas pressure. Further, the size of the hole 4c is small. Therefore, when the stopper 20 is moved up and down in company with the gas valve 13 and the down tube 5 during the beer pouring, the stopper portion 23 is moved up and down without being drawn inside the body 4. As shown in Figs. 4A to 5D, the stopper 20 is constituted by a ring portion 21 which is engaged with the downward surface of the flange portion 11 of the down tube 5, and an arm portion 22 which is bent perpendicularly from the ring portion 21 and extends downward between the coil spring 6 and the body 4. The stopper portion 23 is integrally connected with the arm portion 22 so as to obliquely project from the hole 4c to the outer side of the body 4. The arm portion 22 has a generally inverse U-shaped slit 24 which defines the stopper portion 23 on the arm portion 22. The stopper portion 23 is formed by bending a portion surrounded by the slit 24. More particularly, a base connecting portion 23a of the stopper portion 23 which is connected with the arm portion 22 is bent twice so that there is minor offset between the arm portion 22 and a parallel portion 23b of the stopper portion 23, parallel with the arm portion 22. The tip portion 23c of the stopper portion 23 continuous to the parallel portion 23b is bent obliquely outward and upward so as to obliquely and upwardly project from the hole 4c when the spear tube 1 is installed in the beer keg 2. In order to improve the strength of the stopper portion 23, the cross section of the tip portion 23c of the stopper portion 23 is formed to have a predetermined curvature for reinforcement. That is, as shown in Figs. 4A to 4D, the cross-section of the tip portion 23c of the stopper portion 23 is formed into V-shape. Further, it will be understood that the cross-section of the tip portion 23c of the stopper portion 23 may be formed into arc-shape as shown in Figs. 5A to 5D. The body 4 is formed into a cylindrical shape which has a plurality of ratchets 4b formed at predetermined intervals on the circumferential direction. Through the ratchets 4b, a dispense head or a tool for installation is engaged to an upper opening portion periphery of the body 4. An inner step portion 7 is formed in the vicinity of the upper opening portion of the body 4. An outer step portion 8 is formed at a generally intermediate portion of the body 4 so that a seal ring 9 is disposed between the outer step portion 8 of the body 4 and an inner base of the keg neck interface 3 of the beer keg 2. The body 4 has the hole 4c through which the stopper portion 23 of the stopper 20 is outwardly projected, a plurality of holes 4d functioning as a passage for beer and carbon dioxide gas, and a hollow 10 for the down tube 5. The hole 4c and the holes 4d are formed at the circumferential wall of the body 4, and the hollow 10 is formed at a bottom portion of the body 4. Three bayonet pieces 4e are formed at the bottom portion periphery of the body 4 at equal intervals toward the center axis of the body 4. A retaining disc 12 for supporting the coil spring 6 is hooked on the bayonet pieces 4e. As shown in Figs. 3A and 3B, the retaining disc 12 formed into a ring shape has three grooves 12a formed at equal intervals and depressions 12c and 12d formed at a flange portion 12b. The depression 12d is formed at a portion from the flange portion 12b to the groove portion 12a. The diameter of the flange portion 12b is generally the same as the inner diameter D of the body 4 shown in Fig. 2B. Therefore, by press-fitting the retaining disc 12 to the hollow 10 formed at the bottom portion of the body 4 so as not to overlap the bayonet pieces 4e and the flange portions 12b and by rotating it by 120 degree angle as shown in Fig. 2B, the groove portions 12a are respectively connected to the bayonet pieces 4e so as to be fixed with each other as shown in Fig. 3B. The lower end portion of the coil spring 6 is in contact with the downward surface (upper side) of the groove portions 12a of the retaining disc 12. The inner step portion 7 of the body 4 functions as a valve sheet with which the circular gas valve 13 is fittingly in contact. The lower portion of the gas valve 13 has an outer peripheral portion in contact with the upper surface of the flange portion 11 of the down tube 5 and a lower inner periphery functioning as a valve sheet for the beer valve 14. The outer peripheral portion and the lower inner periphery of the gas valve 13 are in contact with the beer valve 14 pushed (biased) by the coil spring 15 in the down-tube 5. The coil spring 15 is disposed in an enlarged portion 16 of the down tube 5. The flange portion 11 is formed at the upper end portion of the down tube 5. The ring portion 21 of the stopper 20 is in contact with the flange portion 11, and the upper end portion of the coil spring 6 is in contact with the ring portion 21. The lower end portion of the coil spring 6 is in contact with the retaining disc 12 installed in the inner bottom portion of the hollow 10 of the body 4. When the spear tube 1 according to the present invention is installed to the keg neck interface 3 of the beer keg 2 by inserting and screwing, the stopper portion 23 is momentarily bent inward of the inner wall of the body 4 owing to the elastic characteristic thereof. Then, when the stopper portion 23 reaches the hole 4c, the stopper portion 23 protrudes into the hole 4c and out of the body 4. By the installation of the spear tube 1 to the keg neck interface 3, the beer valve 14 is always in contact with the gas valve 13. Therefore, when a not-shown dispense head is installed to the body 4 and when a handle of the dispense head is pushed down, the gas valve 13 and the beer valve 14 are pushed down and opened by a pressuring portion of the dispense head. This opening enables the carbon dioxide gas supplied from a carbon dioxide gas cylinder connected to the dispense head to be flowed into the beer keg 2 through a passage between the gas valve 13 and the body 4. The inner pressure in the beer keg 2 is raised up, and it becomes possible that beer in the beer keg 2 is flowed into the dispense head through the down tube 5, so that the beer is poured from the dispenser into beer mug or jug. At this time, the stopper 20 is moved up and down upon accompanied with the operation of a handle of the dispense head, and the stopper portion 23 is moved up and down while projecting from the hole 4c without being drawn inside of the wall of the body 4. When the spear tube 2 is to be detached from the keg neck interface 3 for maintenance thereof, the dispense head is detached and a tool (not shown) is inserted into the body 4. By the insertion of the tool into the body 4, the down tube 5 is moved down and the residual gas in the beer keg 2 is discharged through a clearance formed between the down tube 5 and the gas valve 13 to the outside of the beer keg 2. Further, when the residual gas is entirely released, the tool is rotated on the axial center of the spear tube 1 so that the external thread portion 4a of the body 4 is detached from the internal thread portion 3a of the keg neck interface 3. If it is not complete to release the gas in the beer keg 2, the spear tube 1 acts to pop out form the keg neck interface 3. However, the stopper portion 23 of the stopper 20 prevents the popping-out of the spear tube 1 by the hooking of the stopper portion 23 to the lower periphery of the keg neck interface 3. Even if the impact of collision is additionally applied to the popping out of the spear tube 1, the stopper portion 23 keeps its shape to perform its functions as a stopper because of the reinforcement by forming its cross-section into curved shape such as a V-shape or arc-shape. In order to completely detach the spear tube 1 from the beer keg 2, it is necessary to pull the stopper portion 23 into an inner side of the body 4 by using a jig. Keeping the stopper portion 23 at a position between the coil spring 6 and the inner wall of the body 4, the spear tube 1 is pulled out from the keg neck interface 3. With this embodiment, the hole 4c of the body 4 has a vertical length which is equal to or greater than a stroke of the down tube 5 moved by a beer pouring operation, and the stopper portion 23 which prevents the spear tube 1 from popping out from the keg neck interface 3 during a detaching operation is projected from the hole 4c. Therefore, it becomes possible to avoid a deforming movement that the stopper portion 23 is drawn inside of the inner wall of the body 4 during the beer pouring. This improves the durability of the stopper portion 23 and suppresses the breakage of the stopper portion 23. Furthermore, the stopper portion 23 is reinforced by being the cross section thereof into a V-shape or arc-shape. Therefore, even if the stopper portion 23 is collided with the lower portion of the body 4, the stopper portion 23 keeps its shape and its function as a stopper. In addition, since the stopper portion 23 is arranged so as not to have a portion at which beer remains, the spear tube 1 is easily cleaned and avoids the decay of beer and a growth of fungus.

Claims: Claims for the following Contracting States : BE, DE, DK, GB A spear tube (1) for a beer keg, the spear tube, when considered in the position in which it is installed in the beer keg in normal use, comprising: a body (4) connectable with a keg neck interface of the beer keg, the body (4) having a side hole (4c) in a cylindrical wall thereof; a gas valve (13) fittingly connected with an inner portion of the body (4); a down tube (5) whose upper end (11) is in contact with the body (4) by way of the gas valve (13); a beer valve (14) disposed in the down tube (5), the beer valve (14) being in contact with a lower peripheral portion of the gas valve (13) functioning as a valve seat; and a stopper (20) for preventing the popping out of the spear tube (1) by residual gas pressure, the stopper (20) including a ring portion (21) which is connected to the down tube (5), an arm portion (22) which extends perpendicularly from the ring portion (21) and lies between the down tube (5) and the cylindrica wall of the body (4), and a stopper portion (23) which projects from the arm portion (22) through the side hole (4c); characterised in that the arm portion (22) has a generally U-shaped slit (24) which defines the stopper portion (23) with respect to the arm portion (22), the stopper portion (23) has a cross-section having a predetermined curvature for reinforcing, and the stopper portion (23) comprises a twice bent connecting portion (23a), an intermediate parallel portion (23b) which is offset parallel to the arm portion (22), and a tip portion (23c) which projects obliquely outward and upward through the side hole (4c). A spear tube as claimed in claim 1, wherein the stopper portion (23) has a V-shaped cross-section. A spear tube as claimed in claim 1, wherein the stopper portion (23) has an arcuate cross-section. A spear tube as claimed in any preceding claim, wherein the side hole (4c) has a lower periphery of a shape corresponding to the curved cross-section of the stopper portion (23). A spear tube as claimed in any preceding claim, further comprising: a first coil spring (6) disposed in the body (4), the down tube (5) including flange portion (11) which is pushed by the first coil spring (6) so that the flange portion (11) is in contact with the gas valve (13); and a second coil spring (15) disposed in an enlarged portion (16) of the down tube (5) and pushing the beer valve (14) toward the gas valve (13). A spear tube as claimed in any preceding claim, wherein the said curved cross-section is provided in the tip portion (23c). Claims for the following Contracting States : AT, CH, ES, FI, FR, GR, IE, IT, LI, LU, MC, NL, PT, SE A spear tube (1) for a beer keg, the spear tube, when considered in the position in which it is installed in the beer keg in normal use, comprising: a body (4) connectable with a keg neck interface of the beer keg, the body (4) having a side hole (4c) in a cylindrical wall thereof; a gas valve (13) fittingly connected with an inner portion of the body (4); a down tube (5) whose upper end (11) is in contact with the body (4) by way of the gas valve (13); a beer valve (14) disposed in the down tube (5), the beer valve (14) being in contact with a lower peripheral portion of the gas valve (13) functioning as a valve seat; and a stopper (20) for preventing the popping out of the spear tube (1) by residual gas pressure, the stopper (20) including a ring portion (21) which is connected to the down tube (5), an arm portion (22) which extends perpendicularly from the ring portion (21) and lies between the down tube (5) and the cylindrical wall of the body (4), and a stopper portion (23) which projects from the arm portion (22) through the side hole (4c); characterised in that the arm portion (22) has a generally U-shaped slit (24) which defines the stopper portion (23) with respect to the arm portion (22), the stopper portion (23) has a cross-section having a predetermined curvature for reinforcing, and the stopper portion (23) comprises a connecting portion (23a), an intermediate portion (23b), and a tip portion (23c) which projects obliquely outward and upward through the side hole (4c). A spear tube as claimed in claim 1, wherein the stopper portion (23) has a V-shaped cross-section. A spear tube as claimed in claim 1, wherein the stopper portion (23) has an arcuate cross-section. A spear tube as claimed in any preceding claim, wherein the side hole (4c) has a lower periphery of a shape corresponding to the curved cross-section of the stopper portion (23). A spear tube as claimed in any preceding claim, further comprising: a first coil spring (6) disposed in the body (4), the down tube (5) including flange portion (11) which is pushed by the first coil spring (6) so that the flange portion (11) is in contact with the gas valve (13); and a second coil spring (15) disposed in an enlarged portion (16) of the down tube (5) and pushing the beer valve (14) toward the gas valve (13). A spear tube as claimed in any preceding claim, wherein the said curved cross-section is provided in the tip portion (23c). A spear tube as claimed in any preceding claim, wherein the connecting portion (23a) is bent twice and the intermediate portion (23b) is parallel to and offset with respect to the arm portion (22).

Inventors: GOMI TATSUYA, GOMI, TATSUYA
Applicants: SUNTORY LTD, SUNTORY LIMITED
Application year: 1997
Main classification: B67D1
IPC codes: B65D83, B67D1