Patent Publication Number: US-6670735-B2

Title: Weight release mechanism for underwater object

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a weight release mechanism for an underwater object. More particularly, the present invention relates to the weight release mechanism of a recyclable underwater object. 
     2. Description of Related Art 
     Underwater objects are often deployed at the bottom of ocean to investigate seismic activities or deployed underwater in other oceanography research projects. To retrieve the underwater object for reuse, most underwater objects are designed to include some self-buoyancy. The self-buoyant underwater object is connected to a dead weight so that the buoyancy is canceled. The dead weight pulls the underwater object to sea bottom so that all kinds of oceanographic researches and tests can be conducted. To retrieve the underwater object, the connection mechanism linking the underwater object and the weight is severed so that the dead weight is discarded while the underwater object rises to the surface under its buoyancy force. The underwater object is then collected for further analysis or reused. 
     After the completion of an underwater mission, the underwater object is released back to the surface by remotely triggering a small explosion to break up the linkage that originally joins the underwater object and the dead weight together. Once the linkage connecting the dead weight and the underwater object is cut, the weight is dumped. Through self-buoyancy, the underwater object rises to the surface for collection. However, the use of explosives by remote control to break the connection is not very reliable. The explosive may damage the underwater object because the precise amount of explosives needed to break up the linkage is difficult to predict. 
     SUMMARY OF THE INVENTION 
     Accordingly, one object of the present invention is to provide a simple-to-operate, low-cost and safe weight releasing mechanism for an underwater object. Through a detachable latching mechanism between the underwater object and a matching weight together with various remote-control driving circuits, the matching weight of the underwater object is easily released. The detachable latching mechanism is a damage-free mechanism that may operate repeatedly to release any attached weights. Since separation of the weight from the underwater object is effected by electrically driven rotation, power needed to release the heavy block can be easily estimated. 
     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a weight releasing mechanism for an underwater object. The releasing mechanism facilitates the separation of the underwater object from a heavy block and hence the subsequent retrieval of the underwater object on the surface of water. The underwater object is intrinsically buoyant and has a groove for engaging a heavy block. The groove has a bottom surface with a through hole. The underwater object&#39;s weight releasing mechanism includes a heavy block, one or more springs, a bearing and an electric motor. 
     The heavy block is engaged inside the groove so that the weight of the heavy block may overcome the buoyancy force of the underwater object and make the underwater object sink to the bottom. The heavy block has a flat surface. The flat surface has a latching groove and a spring groove thereon. The latching groove has an opening. When the heavy block is put inside the heavy block groove, the flat surface of the heavy block is pressed against the bottom surface of the heavy block groove. 
     A spring is put inside each spring groove. Overall length of the spring is larger than the depth of the spring groove. When the heavy block is put inside the heavy block groove, the ends of the spring are in contact with the bottom section of the spring groove and the bottom surface of the heavy block groove respectively. In other words, the spring is compressed to store up a spring load. 
     The bearing is installed inside the underwater object. A rotary spindle is tightly engaged inside the through-hole and fixed relative to the bearing so that the spindle may rotate inside the through hole. The spindle further includes a first end and a second end. The first end is inside the heavy block groove while the second end is inside the underwater object. Furthermore, the first end has an engaging block. The cross-sectional profile of the engaging block at the first end is identical to the opening profile of the latching groove. Hence, the first end of the spindle may insert into the latching groove via the opening so that the engaging block can rotate inside the latching groove. The engaging block may hook to the latching groove interior so that the heavy block is fixed inside the heavy block groove. 
     The electric motor is enclosed inside the underwater object and coupled with the second end of the spindle so that the motor can drive the rotary spindle. The motor may further incorporate a set of rotary speed reduction gears. To ensure a perfect seal between spindle and through hole, a sealing ring may also be added to the spindle. 
     One major aspect of this invention is the introduction of a detachable latching mechanism to engage a detachable heavy block with the underwater object. Hence, the heavy block may be released without employing any explosives. Ultimately, the assembly is much safer to use. 
     Instead of destroying the linkage between the heavy block and the underwater object, the detachable latching mechanism of this invention may be used repeatedly without any damage. 
     Another characteristic of this invention is that the release mechanism is driven by electrically driven rotation so that the power for releasing of the heavy block from the underwater object can be estimated precisely. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
     FIG. 1 is a schematic diagram showing a cross-sectional view of a detachable latching mechanism for engaging a heavy block onto an underwater object according to one preferred embodiment of this invention; 
     FIGS. 2 a  and  2   b  are top and side view showing the engaging position between the engaging block of the rotary spindle and the latching groove on the heavy block according to this invention; 
     FIG. 3 is a schematic diagram showing the heavy block detaching from the underwater object after triggering the release mechanism according to this invention; and 
     FIGS. 4 a  and  4   b  are top and side view showing the releasing position between the engaging block of the rotary spindle and the latching groove on the heavy block according to this invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     FIG. 1 is a schematic diagram showing a cross-sectional view of a detachable latching mechanism for engaging a heavy block onto an underwater object according to one preferred embodiment of this invention. The weight releasing mechanism for an underwater object (refer to FIG. 1) is mainly applied to the release of a heavy block  200  engaged to an underwater object  100 . The underwater object  100  can be retrieved on the surface after releasing the heavy block  200  because the underwater object  100  is able to rise to the surface through intrinsic buoyancy. 
     As shown in FIG. 1, the main body  101  of the underwater object  100  has a heavy block groove  140  for engaging with a heavy block  200 . A bottom surface  144  of the groove  140  has a through hole  142 . A rotary spindle  130  passes through the through hole  142 . The rotary spindle  130  and the through-hole  142  fit together with a tight tolerance. A first end of the spindle  130  is outside the main body but inside the groove  140  while the second end of the spindle  130  is inside the main body  101 . The other side of the bottom surface  142  inside the main body  101  has a bearing  120 . The spindle  130  is fixed by the bearing  120  so that the spindle  130  may rotate inside the through-hole  142 . The interior of the main body  102  further includes an electric motor  110 . The electric motor  110  couples with the second end  132  of the spindle  130  so that the spindle  130  rotates when the electric motor  110  is powered. The first end  131  of the spindle  130  further includes an engaging block  133 . 
     A flat surface  210  of the heavy block  200  has a latching groove  211  and a plurality of spring grooves  212 . Each spring groove  212  has a spring  300  therein. The uncompressed length of each spring  300  is longer than the depth of the spring groove  212 . As the heavy block  200  is placed inside the groove  140 , the flat surface  210  of the heavy block  200  is pushed against the bottom surface  144  of the groove  140 . Meanwhile, both ends of a spring prop against the bottom surface the spring groove  212  and the bottom surface  144  of the heavy block groove  140  so that the spring is compressed to store up elastic energy. 
     In this invention, an identical cross-sectional profile is used for both the engaging block  133  at the first end  131  of the spindle  130  and an opening  213  within the latching groove  211 . FIGS. 4 a  and  4   b  are top and side view showing the releasing position between the engaging block of the rotary spindle and the latching groove on the heavy block according to this invention. When the engaging block  133  is rotated to a position corresponding to the opening  213  as shown in FIGS. 4 a  and  4   b , the first end  131  of the spindle  130  may pass through the opening  213  into the latching groove  211  and rotate inside. FIGS. 2 a  and  2   b  are top and side view showing the engaging position between the engaging block of the rotary spindle and the latching groove on the heavy block according to this invention. On the other hand, when the first end  131  of the spindle  130  inside the latching groove  211  is rotated to a position away from the opening position  213 , the engaging block  133  is unable to disengage through the opening  213  of the latching groove  211 . Hence, the engaging block  133  is hooked inside the opening  213  and the heavy block  200  is stationed inside the groove  140 . In other words, the heavy block  200  and the underwater object  100  are joined together facilitating underwater operation. 
     To retrieve the underwater object  100 , various time or remote control circuit (not shown) may be used to trigger the electric motor  110 . The electric motor  110  drives the spindle  130  so that the engaging block  133  rotates to a position corresponding to the opening  213  (as shown in FIG. 4 a ). Thereafter, the engaging block  133  may slip out through the opening  213 . The loaded springs  300  inside various spring grooves  212  also assist the ejection of the underwater object  100  away from the heavy block  200  as shown in FIG.  3 . The released underwater object  200  floats to the surface due to intrinsic buoyancy and is subsequently collected. 
     To ensure a tight seal between the rotary spindle  130  and the through-hole  142 , a seal ring  400  is often added to the spindle  130  as shown in FIGS. 2 b  and  4   b . Furthermore, a set of gears may also be used to reduce the rotation speed or increase the torque of the electric motor  110 . 
     In conclusion, major advantages of this invention includes: 
     1. A detachable latching mechanism is introduced between the underwater object and a heavy block. Latching is driven by an electric motor controlled through an electric circuit. Since explosives are no longer used, the assembly is safe to handle. 
     2. Since no explosives are used in the detaching mechanism, damages to components are minimized and hence the underwater object is quite durable. 
     3. Since the heavy block attached to the underwater object is released by electrically driven rotation, power needed to carry out the release can be accurately estimated. Moreover, various electrical circuits may be used to time and control the moment of release. 
     4. The detachable latching mechanism is simple to operate and easy to install inside various types of underwater objects. In addition, the heavy block to be discarded is made from low cost material. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.