Pipe joints or couplings – With means blocking release of holding means
Reexamination Certificate
2000-04-13
2002-05-07
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
With means blocking release of holding means
C285S084000, C285S087000, C285S091000, C285S114000, C285S119000, C285S352000, C285S360000, C285S906000
Reexamination Certificate
active
06382680
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a coupler apparatus, for example, a coupler apparatus for coupling hoses such as fire hoses or coupling a hose and a device such as a pump, or a coupler apparatus for coupling other members, and a method of manufacturing such coupler apparatus. More particularly, this invention relates to a coupler apparatus comprising a pair of main bodies having identical structures without distinction between male and female structures, and a method of manufacturing the same.
In a conventional coupler apparatus, for example, a conventional insertion-type coupler apparatus for fire hoses, a pair of coupler bodies to be coupled comprise distinctive male and female bodies. One of the coupler bodies is constructed as a male metal fitting member, and the other as a female metal fitting member. Male metal fitting members cannot be coupled to each other, nor can female metal fitting members be coupled to each other. For example, in case of fire fighting, where a plurality of fire hoses are extended and coupled, the fire hoses may be misarranged such that the male fitting members or female fitting members are opposed to each other. Such misarrangement should preferably be prevented in view of facility and exactness in fire fighting. In addition, in the case of the conventional coupler apparatus, two types of metal fitting members with different structures, i.e. a male metal fitting member and a female metal fitting member, have to be manufactured, and this increases the manufacturing cost.
In order to overcome such drawbacks, there is a demand for an insertion-type coupler apparatus which comprises a pair of complementary coupler bodies with no distinction between male and female and with identical structures, wherein the coupler bodies can be freely coupled with no distinction between male and female, can be easily coupled/decoupled, have simple structures and high reliability, and can be manufactured at low cost.
Such a coupler apparatus, an apparatus can be thought of, wherein engaging projections and engaging recesses are mutually engaged in the axial direction and engaging hook portions provided on side faces of the engaging projections and engaging recesses are engaged in the circumferential direction, whereby a pair of coupler bodies are coupled. Various kinds of geometrical shapes can be considered as shapes of engaging portions of the coupler apparatus with such structure. In an actual coupler apparatus, however, smoothness of coupling, reliability, etc. need to be taken into account, and the following problems, for example, need to be considered.
A first problem is tightness in contact between, and machining of, the aforementioned complementary engaging projections and recesses.
In this type of coupler apparatus, the engaging projection and engaging recess are engaged. Thus, the smoothness in coupling/decoupling, and reliability, strength, etc. in coupling are greatly affected by the precision of the engaging projection, engaging recess and engaging portion. These elements are precisely machined by cutting. Specifically, cylindrical works for forming the coupling bodies are first manufactured, and then end portions thereof are milled. Thus, the engaging projection and engaging recess are formed.
Since these engaging projections and engaging recess have complementary shapes, the engaging recesses are cut at predetermined intervals and thus those portions intervening among the engaging recesses are formed as engaging projections. Where the engaging projections and engaging recesses are milled, one engaging recess is cut in the work, the work is then rotated by a predetermined angle, and a next engaging recess is cut. In this way, all engaging projections and engaging recesses are formed.
For example, where the number of engaging projections and the number of engaging recesses are six, respectively, these engaging recesses are formed at intervals of 60°. In addition, since these engaging projections and engaging recesses are substantially complementary, as mentioned above, the engaging projection and engaging recess are formed over about 30°.
In a general milling machine, a work is fixed and a milling tool is moved in one or two axes along a predetermined locus. The work is thus cut into a predetermined shape. In the case of the cutting by the milling machine, the cut faces of the respective parts are normally parallel to one another. Accordingly, for example, both inner faces of one engaging recess are parallel to each other, and also both side faces of an engaging projection formed between the engaging recesses are parallel to each other. Consequently, for example, if one inner side face or side face formed on the aforementioned engaging hook portion is a radial face passing through a central axis of the cylindrical coupler body, the other inner side face or side face is inclined at about 30° to the radial direction.
As a result, where the coupler bodies are to be abutted on and engaged with each other, the other side face of the engaging projection of one of the coupler bodies and the other inner side face of the engaging recess of the other coupler body are displaced by 30° from each other in opposite directions in respect of the radial face extending through the central axis. Consequently, a large gap is created between these side face and inner side face.
If such a gap is created, sand or pebbles enter the gap and cause malfunction of the coupler. Moreover, if the side face and the inner side face are engaged with an angle in the radial direction, a radial component force will occur in a reaction force acting therebetween. Besides, where the other side face or inner side face, for example, is provided with an urging mechanism, etc. for urging and engaging the aforementioned engaging hook portions in the circumferential direction, circumferential and radial component force will occur in the urging force of the urging mechanism.
According to various test results, it has turned out that drawbacks, such as loss of smoothness of coupling/decoupling of the coupler apparatus, occur due to the component force. Specifically, where the coupler bodies are to be coupled, the engaging projections and engaging recesses of the paired coupler bodies are axially engaged against the urging force of the urging mechanism until the engaging hook portions are completely engaged. In this case, if the radial component force is non-uniform among the engaging projections or engaging recesses, an undesirable radial repulsive force will occur in these coupler bodies. Consequently, the center axes of the paired coupler bodies are misaligned or inclined. Such drawbacks will deteriorate smoothness of coupling/decoupling.
In order to overcome the drawbacks, it is thought to incline said one side face or inner side face and the other side face or inner side face by equal angles in respect of the radial direction, e.g. 15°. However, where the internal pressure of the hoses is acting, a great axial load will act on said one side face or inner side face on which the engaging hook portion is provided. It is thus undesirable to inline the side face or inner side face in respect of the radial direction, on which such a load acts and the engaging hook portion is provided.
In order to facilitate mutual engagement of the engaging projection and engaging recess, it is desirable that the engaging projection and engaging recess be tapered such that the width thereof in the circumferential direction decreases toward the distal end or toward the bottom. In this case, however, the side face and inner side face of the engaging projection and engaging recess are also inclined in respect of the axial direction, and the directions of the aforementioned component force become more complex. A predetermined gap is provided for smooth engagement between the engaging projection and engaging recess. This gap may cause the central axes of the paired coupler bodies to be easily displaced or inclined during coupling. Consequently, the smoothness in engagement may be deteriorated due t
Luu Teri Pham
Sakura Rubber Co. Ltd.
Volpe and Koenig P.C.
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