A CLAW

Abstract: A claw (1) comprises a casing (2), defining an inner space (3), at least one inlet member (4), an outlet pipe (5) and a valve device. The latter comprises a valve body which is movable between an open position, at which the outlet pipe (5) is in connection with the inner space (3), and a closed position, at which the connection between the outlet pipe and the inner space is essentially closed. Furthermore, the valve device comprises an operating member (14) by means of which the valve body is lockable at said open position. The operating member (14) is rotatable between two end positions and comprises a first locking means (20) in the shape of a recess arranged to engage a second locking means (8, 23) in the shape of an element at least at one of said end positions for locking the valve body (12) at said open position. The element is arranged to extend in the recess when the locking means engage each other.

Description: A claw BACKGROUND OF THE INVENTION AND PRIOR ART The present invention refers to a claw comprising a casing, defining an inner space, at least one inlet member, an outlet pipe and a valve device which comprises a valve body movable between an open position at which the outlet pipe is in connection with the inner space, and a closed position, at which the connection between the outlet pipe and the inner space is essentially closed, the valve device comprising an operating member by means of which the valve body is lockable in said open position, the operating member being rotatable between two end positions and comprising a first locking means arranged to engage a second locking means at least at one of said end positions for locking the valve body at said open position. It is known to provide claws with such valves which during milking are essentially open in order to permit the transport of the milk from the claw to a milk collecting container of a milking plant. Furthermore, these valves are to be arranged in such a manner that if one or possibly two teatcups are detached from their respective teats, the valve is to close quickly in order to prevent air from rushing into the claw and further to the milk collecting container. Besides the disadvantage of getting air into the system and into contact with the milk, a consequence of such an air rush is that particles and micro-organisms etc. will deteriorate the quality of the milk. Furthermore, it is known to provide such valves with some sort of locking function in such a manner that they may be locked at the open position in order to enable an easy and effective washing of the claw by flushing of cleaning liquid into the claw via the teatcup. In order to obtain such a locking function, it is known to provide the valve with an operating member which may be rotated in such a manner that it, when the valve is open, in a determined position of rotation is fixedly held against a projection or the like. Operating members known up to now have the disadvantage of being difficult to handle, for instance due to the fact that they are difficult to reach. Furthermore, the locking position is frequently not sufficiently distinct, so that a searching operation is necessary in order to enable locking of the operating member. DK 121 477 discloses a claw of the initially defined art. The claw comprises a valve device extending downwardly from the casing of the claw in such a manner that an operating member in the shape of a rotatable arm is located beneath the claw. The operating member comprises a plate shaped part arranged to engage two opposite recesses provided in two bars extending downwardly from the casing of the claw. Thereby, the bars comprise a first pair of recesses for locking the valve device in an open position and a second pair of recesses for locking the valve device in a closed position. The operating member disclosed has a complicated structure and is difficult to operate since the rotatable arm has to engage two recesses in order to obtain locking of the valve device. SUMMARY OF THE INVENTION The object of the present invention is to remedy the problems mentioned above and improve the ability of handling of the valve defined above for a claw. This object is obtained by the claw initially defined and characterized in that said first locking means comprises a recess and said second locking means an element extending in the recess when the locking means are in engagement with each other, said recess being provided in an inwardly curved side surface portion of the operating member. By rotating the operating member towards the element while applying a certain force, the operating member and the valve body are locked to each other. Thereby, the advantage is obtained that the user experiences that the locked position has been reached and the user does not need to look therefor. In such a manner the handling and the operation of the claw is facilitated. According to one embodiment of the invention, said first and second locking means are arranged to be snapped into engagement with each other. By means of such a snap engagement, offering a certain resistance for bringing the locking means in engagement with and disengagement from each other, i.e. the force of a certain level has to be overcome, it is ensured at on the one hand that the locked position is not loosened without an active contribution of a user and on the other hand that the valve body will not get locked without an active contribution of a user. Furthermore, the operating member may comprise a body piece forming said first locking means, the recess extending in the body piece from an essentially concave portion of the side surface of the body piece. Such a body piece may in an easy manner be handled and made comfortable to grip. According to a further embodiment of the invention, said first locking means is arranged to engage said second locking means at either of said two end positions. Thereby, the handling is further facilitated. The user may rotate the operating member at any direction in order to provide locking of the valve body at its open position. Thereby, said first locking means may comprise a first recess and a second recess and said element is arranged to extend in the first recess, when the operating member is in said one end position, and extend in the other recess, when the operating member is in said second end position. The first and second recesses may extend in the body piece from said inwardly curved side surface portion of the body piece. Furthermore, the recesses may extend symmetrically in the body piece from said portion with regard to an axis about which the operating member is rotatable. According to a further embodiment, said element is provided at the casing in such a manner that it extends outwardly therefrom. According to a further embodiment of the invention, the valve device comprises an elongated connecting member arranged to connect the valve body to the operating member and extending through an opening in the casing. Advantageously, the valve body is adjustable to said open and closed positions by a longitudinal displacement of the connecting member in the opening. Thereby, the connecting member and the opening may advantageously be shaped in such a manner that said displacement is enabled, whereas a rotation of the connecting member in relation to the opening is prevented. According to a further embodiment of the invention, said second locking means comprises a stop member arranged to prevent said displacement of the connecting member when said locking means are in engagement with each other. Advantageously, the stop member comprises a projection projecting from said element. Consequently, when the locking means are in engagement with each other the stop member prevents all displacement of the operating member and the valve body. According to a further embodiment of the invention, a connecting member is arranged to connect the valve body and the operating member in such a manner that the operating member is rotatable in relation to the valve body. Advantageously, the valve body is fixedly connected to the connecting member and the operating member is rotatably connected to the connecting member. Thus, the valve body will not be rotatable but merely displaceable by a translatory movement. In such a manner, an effective sealing against the outlet pipe may be obtained in an easy manner. According to a further embodiment, the valve body is arranged to close against a valve seat provided at the orifice of the outlet pipe in the inner space, the valve body comprising a spherical surface having a radius of curvature being greater than the radius of curvature of an imaginary sphere, completely enclosing the valve body, and the spherical surface of the valve body is arranged to abut a spherical surface of the valve seat. Due to the limited space within the claw, an improved sealing may be obtained by such a spherical surface being relatively great in relation to the valve body. According to a further embodiment of the invention, said element ay comprise a bar extending outwardly from the casing. Said bar may comprise a hook-like member for the suspension of the claw. In such a manner few components are required for the claw according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is now to be explained more closely by means of different embodiments and with reference to the drawings attached hereto. Fig 1 discloses a perspective view of a claw according to the present invention. Fig 2 discloses a sectional view of an upper part of the claw in Fig 1. Fig 3 discloses a perspective view from above of a part of the claw in Fig 1. DETAILED DESCRIPTION OF DIFFERENT EMBODIMENTS With reference to Fig 1 and 2, a claw 1 is disclosed which has a casing 2 defining an inner space 3. In the casing 2 four inlet members 4 are provided, which each, via a respective short milk conduit (not disclosed), are connected to a respective teatcup (not disclosed) for attachment to a teat. The milk extracted from teats is led via the inlet members 4 into the inner space 3 of the claw 1 and from there it is transported via a common outlet pipe 5 and a long milk conduit to a milk collecting container of a milking machine (not disclosed). The casing of the claw 1 comprises an upper part 6 and a lower part 7, which are kept together by means of a bar 8 extending through the claw 1. The bar 8 comprises a washer 9 fixedly provided thereon and abutting the upper part 6, and a thread provided at the lower part of the bar and onto which a nut 10 is screwed in order to connect the upper part 6 and the lower part 7. The bar 8 is prolonged upwardly and comprises at its upper end a hook 11 for the suspension of the claw 1. It is to be noted that the part of the bar 8 provided with the suspension means and the part for compressing the claw 1 together may be formed by two separate components. Furthermore, the claw 1 is provided with a valve device comprising a valve body 12 which is arranged to take an open position, at which the outlet pipe 5 is in connection with the inner space (disclosed in Fig 2), and a closed position, at which the valve body 12 closes the connection between the outlet pipe 5 and the inner space 3. The valve body 12 is fixedly connected to a connecting member 13 in the shape of a bar, which in turn is rotatably attached to an operating member 14. The operating member 14 comprises a body piece which in the embodiment disclosed is in the shape of a plate. The bar 13 extends through an opening 15 in the upper part 6 of the claw 1 in such a manner that the valve body 12 may be displaced upwardly and downwardly between the open and closed position. The bar 13 and the opening 15 have a non-circular cross section so that the bar 13 may not rotate in the opening 15. The opening 15 comprises at its upper part a recess 16 which is closed outwardly by a substantially flat bottom surface portion of the plate 14 when the valve body 12 is in the open position, see Fig 2. Since there is a small gap between the bar 13 and the opening 15, the subpressure prevailing in the inner space 3 will propagate to the outwardly closed recess 16 when the valve body 12 is in the open position. In such a manner, it may be ensured that the valve device is kept open during milking. If in this position one or more teatcups are detached from their respective teats, air will rush into the inner space 3 of the claw 1 via the inlet members 4, thereby quickly reducing the subpressure prevailing in the inner space 3 and the closed recess 16, and the consequence thereof is that the air flow through the claw 1 may exert a lifting force to the valve body 12 being sufficiently great to move the latter to the closed position. In the closed position, the valve body 12 is arranged to close against a valve seat 17 provided around the orifice of the outlet pipe 5 in the inner space 3. The valve body 12 comprises a spherical sealing surface 18 having radius r of curvature being greater than the radius of curvature of an imaginary sphere 19 completely enclosing the valve body 12. The centre point of the spherical surface 18 is located below the sealing surface 18. The valve seat 17 also comprises a spherical surface against which the spherical surface 18 of the valve body 12 is provided to seal. The radius r of curvature of the spherical surface 18 of the valve body 12 is somewhat less than or equal to the radius of curvature of the spherical surface of the valve seat 17. In such a manner a good sealing function is obtained between the valve body 12 and the valve seat 17. In order to be able to lock the valve body 12 in the open position, the valve device comprises a first locking means 20 forming two recesses 20a and 20b in the plate 14 and the second locking means in the shape of an element extending from the casing 2 and being the bar 8 in the embodiment disclosed. The recesses 20a, 20b are symmetrically provided in an inwardly curved, essentially concave side surface portion 22 with regard to an axis y about which the plate 14 is rotatable, see Fig 3. The essentially concave portion 22 forms a partly enclosed space in which the bar 8 is located and defines the end positions of the plate 14. It is to be noted that the concave portion 22 does not need to be continuously concave but may demonstrate local convex areas. By rotating the plate 14 in any one direction to one of the end positions it will engage the bar 8 in such a manner that the bar 8 is enclosed by or extends in one of the recesses 20a, 20b. The recesses 20a, 20b are shaped in such manner that their opening width facing the bar 8 is somewhat less than the diameter of the bar 8 and the width of the recesses 20a, 20b increases inwardly from the opening. Seen from above the recesses 20a, 20b have a shape corresponding to a part of a circle. This part is somewhat greater than a semicircle. Furthermore, the plate 14 is manufactured in any elastic material, such as rubber or plastic, so that the width of the recesses 20a, 20b, at least in the area of the opening, may be resiliently widened. In such a manner the first locking means 20 will engage the bar 8 by means of a snap action, i.e. a force of a certain level is required to obtain that the bar 8 engages the first locking means 20 and thereby extends in any of the recesses 20a, 20b, and equally for loosening the bar and the first locking means 20 from each other. The plate 14 disclosed has an upper essentially plane limiting surface and a lower essentially plane limiting surface. These limiting surfaces are connected to a surrounding side surface 21 forming said essentially concave portion 22. In order to prevent the plate 14 and thus the valve body 12 from being displaced upwardly when the bar 8 extends in one of the recesses 20a, 20b, the bar 8 is provided with a stop member 23 in the shape of a projection, which in its most simple embodiment may comprise an upsetting of material extending outwardly from the bar 8. The present invention is not limited to the embodiments disclosed above but may be varied and modified within the scope of the following claims. The second locking means may be a separate component and may not be a part of the bar for keeping the claw 1 together or for its suspension. The claw may be kept together in many different ways and the second locking means may comprise an element extending from the casing, for example a bar. The plate 14 and the bar 8 may be utilized as locking means for valve bodies of a variety of different other embodiments. For instance, the valve body may be rotatable about its displacement axis. The body piece may have another shape than the plate-like shape disclosed. For instance, the top portion of the body piece may be spherical or curved in any other manner. It is essential that the body piece has a bottom surface being able to close off the recess 16. The bar 8, for the function of the second locking means, may have another shape. For instance, the second locking means may be formed by a relatively short bolt member extending from the casing 2 or the outlet pipe 5 provided at the top level of the upper part 6. Such a bolt member may be provided with a bolt head forming said stop member 23.

Claims: Claims 1. A claw comprising a casing (2), defining an inner space (3), at least one inlet member (4), an outlet pipe (5) and a valve device which comprises a valve body (12) movable between an open position at which the outlet pipe (5) is in connection with the inner space (3), and a closed position, at which the connection between the outlet pipe (5) and the inner space (3) is essentially closed, the valve device comprising an operating member (14) by means of which the valve body (12) is lockable in said open position, the operating member (14) being rotatable between two end positions and comprising a first locking means (20) arranged to engage a second locking means (8, 23) at least at one of said end positions for locking the valve body (12) at said open position, characterized jri that said first locking means (20) comprises a recess (20a, 20b) and that said second locking means comprises an element (8) extending in the recess (20a, 20b) when the locking means engage each other, said recess (20a, 20b) being provided in an inwardly curved side surface portion of the operating member (14). 2. A claw according to claim 1 , characterized in that said first and second locking means (20, 8) are arranged to be snapped into engagement with each other. 3. A claw according to any one of claims 1 and 2, characterized in that the operating member (14) comprises a body piece which forms said first locking means (20), the recess (20a, 20b) extending in the body piece from an essentially concave portion of the side surface (21 ) of the body piece. 4. A claw according to any one of claims 1 and 2, characterized in that said first locking means (20) is arranged to engage with said second locking means (8) in either of said two end positions. 5. A claw according to any one of claims 1 to 4, characterized in that said first locking means (20) comprises a first recess (20a) and a second recess (20b), and that said element (8) is arranged to extend in the first recess (20a), when the operating member (14) is in said one end position, and extend in the second recess (20b), when the operating member (14) is in said second end position. 6. A claw according to claim 5, characterized in that the first and second recesses (20a, 20b) extend in the body piece from said inwardly curved side surface portion of the body piece (14). 7. A claw according to claim 6, characterized in that the recesses (20a, 20b) extend symmetrically in the plate from said side surface portion with regard to an axis (y) about which the operating member (14) is rotatable. 8. A claw according to any one of the preceding claims, characterized in that said element (8) is provided at the casing (2) in such a manner that it extends outwardly therefrom. 9. A claw according to any one of the preceding claims, characterized in that the valve device comprises an elongated connecting member (13) arranged to connect the valve body (12) to the operating member (14) and extending through an opening (15) in the casing (2). 10. A claw according to claim 9, characterized in that the valve body (12) is adjustable to said open and closed positions by longitudinal displacement of the connecting member (13) in the opening (15). 11. A claw according to claim 10, characterized in that the connecting member (13) and the opening (15) are shaped in such a manner that said displacement is enabled, whereas rotation of the connecting member (13) in relation to the opening (15) is prevented. 12. A claw according to any one of claims 9 and 1 1 , characterized in that said second locking means (8) comprises a stop member (23) arranged to prevent said displacement of the connecting member (13) when said locking means (8, 20) are in engagement with each other. 13. A claw according claim 12, characterized in that the stop member comprises a projection (23) projecting from said element (8). 14. A claw according any one of claims 9 to 13, characterized in that the connecting member (13) is arranged to connect the valve body (12) to the operating member (14) in such a manner that the operating member (14) is rotatable in relation to the valve body (12). 15. A claw according to claim 14, characterized in that the valve body (12) is fixedly connected to the connecting member (13) and that the operating member (14) is rotatably connected to the connecting member (13). 16. A claw according to any one of the preceding claims, characterized in that the valve body (12) is arranged to close against a valve seat (17) which is provided at the orifice of the outlet pipe (5) in the inner space (3) and that the valve body (12) comprises a spherical surface (18) having a radius of curvature (r) which is greater than the radius of curvature of a imaginary sphere (19), completely enclosing the valve body (12), and that the spherical surface (18) of the valve body (12) is arranged to abut a spherical surface of the valve seat (17). 17. A claw according to any one of the preceding claims, characterized in that said element comprises a bar (8) extending outwardly from the casing (2). 18. A claw according to claim 17, characterized in that said bar (8) comprises a hook-like member (11 ) for the suspension of the claw (1 ).

Inventors: GUSTAFSSON MARIE-LOUISE, GUSTAFSSON, MARIE-LOUISE
Applicants: ALFA LAVAL AGRI AB, GUSTAFSSON MARIE LOUISE, GUSTAFSSON, MARIE-LOUISE
Application year: 1997
Main classification: A01J5
IPC codes: A01J5