US3534418A - Spring loaded hydrastatic release - Google Patents

Description

Oct. 20, 1% a... D. ADAMS, JR

SPRING LOADED HYDRASTATIC RELEASE 2 Sheets-Shet 1 Filed June 20. 1968 I INVENTOR. BY Leland D. Adams, Jz

2norneys Oct. 20, 1970 L. D. ADAMS, JR 3 5 SPRING LOADED HYDRASTATIC RELEASE Filed June 20, 1968 2 Sheets-Sheet 2 INVENTOR.

Attorneys United States Patent O 3,534,418 SPRING LOADED HYDRASTATIC RELEASE Leland D. Adams, Jr., Atherton, Califi, assignor to C. J.

Hendry Company, San Francisco, Calif., a corporation of California Filed June 20, 1968, Ser. No. 738,692 Int. Cl. B63b 23/62; B63c 9/22 US. Cl. 933 2 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION Hydrastatic pressure release coupling devices have been provided in the past as exemplified by US. Pats. Nos. 2,360,848 and 2,824,315. Such coupling devices have been found to operate satisfactorily but in some instances re lease of the latching plates particularly by manual actuation, has been impeded by the fact that the plates do not separate once unlatched. In order to overcome this difliculty lashing straps which have been atlixed to the lashing plates are secured to the vessel deck, raft cradle, or other fixed structure by means of a spring. Such spring connected lashing straps have presented problems particularly when used with life rafts packaged in containers. In these instances in order for the lashing strap to actually separate the lashing plate after unlatching, the springs must pull the strap itself across the raft container. The friction between the strap and the raft varies considerably not only because of diiferences in material, and weather conditions but also because of the container shape. Some of the containers are cylindrical but others are rectangular or cubic in shape. In the case of rectangular containers the lashing strap passes over relatively sharp edges which, of course, severely impede the lineal movement of the strap. Frequently, the spring tension under such conditions, is insufficient, to move the lashing strap enough to separate the lashing plates. Moreover, the use of spring connected lashing straps presents another diflicult problem in testing the coupling device which must, for safety considerations, be done periodically. Because of the difiiculty in testing the entire coupling device, lashing strap and spring combination, it has been found that the testing has almost totally ignored the strap and spring portion of the combination.

SUMMARY OF THE INVENTION AND OBJECTS A hydrastatically and manually operated coupling device including two lashing plates releasably secured to each other and having included in one of the plates a spring whereby the coupling device itself provides sufficient resilient separating force and movement to separate the lashing plates once they are unlatched either manually or by hydrastatic pressure.

It is a general object of this invention to provide a resiliently disconnected hydrastatic coupling device in which the resilient force is developed by a spring in one of the lashing plates.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view showing a life raft container in phantom line held to the cradle by means of a ice lashing strap and a hydrastatic coupling in accordance with this invention;

FIG. 2 is a front elevational view of the hydrastatic coupling shown in FIG. 1;

FIG. 3 is a side elevational view of the hydrastatic coupling shown in FIGS. 1 and 2;

FIG. 4 is a front elevational view of one of the lashing plates of the coupling device shown in FIGS. 2 and 3 showing particularly the spring loading member;

FIG. 5 is a side elevational view taken along the lines 5-5 of FIG. 4;

FIG. 6 is a sectional view taken along the. line 6-6 of FIG. 4;

FIG. 7 is a sectional view taken along the lines 7--7 of FIG. 4;

FIG. 8 is a sectional view taken along the lines 88 of FIG. 4;

FIG. 9 is a sectional view taken along the lines 9--9 of FIG. 4; and

FIG. 10 is a sectional view taken along the litres 10-10 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there is shown a cradle 11 secured to channel members 13 by means of bolts 15. The channel members 13, in turn, are securely fastened to the deck, or, other fixed structure, of a vessel by Welding, -bolts or any other convenient means. The cradle 11 includes a pair of end frames 17 having upper container support members 19. The end members 17 are rigidly secured together by means of a back brace 21 and a generally V- shaped front brace 23. A container 25 is fitted on the support members 19 and a lashing strap 27 folded and formed in the shape of the V has its end secured to the back brace 21 by means of T-bolts 29 or the like. The crotch of the V-shaped lashing strap 27 receives a pin 31 to which is attached a releasable coupling device 33. The other side of the device 33 is secured to the V-shaped front brace 23 by means of a hook 35 carried by the support 23.

Referring to FIGS. 2 and 3, the releasable coupling device 33 includes a first coupling member 37 and a sec-.

ond coupling member 39. The coupling member 37 may be of the type defined in the aforementioned Pat. No. 2,824,315 as shown or may be of any other conveniently available type. In general, the coupling member 37 includes a rigid lashing plate 41 formed of a pair of sheets 43 between which are pivotally secured a pair of dogs 45. The member 37 also includes a cup 47 which houses a spring and diaphragm (not shown but fully explained in said Pat. No. 2,824,315) to which is attached a plunger 49. The plunger 49 includes a button portion 51, a narrow shaft portion 53 and an enlarged shaft portion 55. The plunger 49 is carried by the diaphragm within the coupling 47. With the plunger in the position shown in.

FIGS. 2 and 3 the large diameter portion 55 lies between the inner ends of the dogs to thereby limit their movement toward each other. When the plunger is pushed in or to the right as shown in FIG. 3 the small diameter portion 53 is in alignment with the dogs 45 whereby the dogs may be moved toward each other in the manner described in said Pat. No. 2,824,315.

The coupling member 39 is better shown in FIGS. 4 through 10 and it too includes a rigid lashing plate comprised of a pair of sheets 57 held together by means of rivets 59. The sheets 57 are separated at one end to form an opening 61 within which is located a pair of lugs 63. With the members in the position as shown in FIGS. 2 and 3 the lugs 63 cooperate with the dogs 45 to prevent seperation of the members. Because of the relative position of the pivot points of the dogs 45 and their point of contact with the lugs 63 tension between the members 37 and 39 will cause the dogs 45 to be rotated toward each other until they clear the lugs 63 if the narrow shaft portion 53 of the plunger 49 is aligned with the dogs 45. Thus, the members.37 and 39 may be separated.

It should be noted, however, that the mere depression of the plunger 49 and alignment of the narrow shaft portion 53 with the dogs 4-5 neither causes separation of the members 37 and 39 nor rotation of the dogs 45 about their pivots.

The sheets 57 are each formed with raised portions 65 which cooperate to form a spring housing 67 and shaft guide 59. A hook shaft 71 extends through the guide 69 and into the housing '67. A spring retainer cup 73 is secured to the end of the shaft 71 and receives a compression spring 75 which is carried about the shaft 71. The opposite end of the spring 75 abuts against the wall 77 of the spring chamber 67.

When the coupling device is mounted for operation the installation is such as to place the spring 75 under compression. With the spring 75 under compression the hook shaft 71 is extended from the lashing plate 39 as shown in FIGS. 2 and 3. During installation of the hydrastatic coupling the ends of the lashing strap 27 are secured to the plate 21 as shown in FIG. 1 and passed over the container to be secured. The coupling member 37 is attached to the hook 35 and the hook shaft 71 is extended against the compression of the spring 75 and passed over the pin 31 received by the crotch of the lashing strap 27.

Alternative to the embodiment shown, the hook member 35 may be received by the V-shaped bracket 23 in such a manner as to be vertically adjustable. The spring 75 may then be compressed after the coupling device is mounted between the lashing strap 27 and the hook 35. Such a means may be in any conventional manner such as threading the shaft portion of the hook 35 and passing the threaded shaft through a tube which is secured to the V-shaped member 23 and restraining the hook 35 within the tube by means of a nut.

In the event that the life raft so retained is needed such as when the vessel sinks the releasable coupling device will come into play. If the vessel sinks in water deep enough to submerge the hydrastatic release to a predetermined depth such, for instance, as ten or fifteen feet, hydrastatic pressure will act upon the diaphragm in the cup 47 to depress the plunger 49. The buoyant load caused by the raft container 25 itself will cause separation of the coupling members 37 and 39 and consequent release of the load.

If, on the other hand, the raft is required in circumstances wherein the coupling device is not submerged the predetermined depth, such as where the vessel may sink in shallow water or if it is desired to release the raft prior to the actual sinking, manual depression of the plunger 49 will serve the same purpose. In this instance, however, there will be no buoyant load from the raft container 25. Here, the spring 75 expands to provide the necessary separating tension and travel between the members 37 and 39. Since the lashing strap 27 remains stationary during the operation of the spring the entire force of the spring is transferred directly to the separation of the coupling members.

When, as is desirable with seagoing safety devices, the releasing coupling device is to be tested, the entire coupling device including members 37 and 39 may be removed and placed into a relatively small testing chamber. With such a chamber not only will the operation of the plunger 49 be tested but also the operation of the spring 75. Consequently, all of the operating parts of the entire releasable coupling system may be conveniently and easily checked periodically.

What is claimed is:

1. A coupling mechanism for releasably securing a lashing strap partially about a buoyant object to be held to a vessel to thereby releasably secure the object to the vessel and comprising first and second lashing plates, cooperative latching means carried by said first and second lashing plates and moveable between an engaged position in which the first and second lashing plates are held together by said latching means and a disengaged position in which separation of said lashing plates is permitted, said cooperative latching means being formed in such a manner that tension between the first and second lashing plates urges the latching means from its engaged to its disengaged position, one of said lashing plates including a plunger moveable between two positions one of which positions permits said cooperative latching means to move to its disengaged position and the other of which positions prevents movement of said cooperative latching means to said disengaged position, means responsive to hydrostatic pressure for moving saidplunger to said one position, further manual means for moving said plunger to said one position, and spring means secured between one of said lashing plates and said lashing strap for continuously applying sufficient tension between said lashing plates to cause movement of said cooperative latching means to said disengaged position and separation of said lashing plates regardless of tension being applied to said lashing plates independent of said spring means whereby said object may be released from the vessel either by hydrastatic action or manually regardless of any friction between the lashing strap and the object.

2. A coupling mechanism as defined in claim 1 wherein one of said lashing plates defines a spring housing, a coil spring within said housing, a hook member having one end extending into said housing and through said coil spring, means securing said one end of the hook member to an end of said coil spring, the other end of said coil spring being in engagement with a wall of said housing.

References Cited UNITED STATES PATENTS 6/1931 Butler 9--32X 2/1958 McKenny 9-33

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