US3628821A

US3628821A - Ocean bottom release device

Info

Publication number: US3628821A
Application number: US1476A
Authority: US
Inventors: Asa M Reece
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1970-01-08
Filing date: 1970-01-08
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21

Abstract

A bottom release device for placing a load on the ocean floor in a desired position from a shipboard crane or winch. The device combines a spring-operated release for releasing a shacklesupported load whenever the load comes off the spring such as occurs when the load comes to rest on the ocean bottom and a hydrostatic plunger for preventing operation of such spring release until the ambient pressure thereon is equal to the pressure at a predetermined water depth.

Description

United States Patent Asa M.- Reece 3,271,833 9/1966 Wendroif 294/83 X 3,337,255 8/1967 Nicoloff 294/66 3,504,407 4/1970 Dawson 294/83 X Primary Examiner-Joseph Wegbreit Assistant Examiner-Bruce H. Stoner, Jr.

Attorneys-R. S. Sciascia, .l. A. Cooke, A. J. Erickson and M.

G. Raskin ABSTRACT: A bottom release device for placing a load on the ocean floor in a desired position from a shipboard crane or winch. The device combines a spring-operated release for releasing a shackle-supported load whenever the load comes off the spring such as occurs when the load comes to rest on the ocean bottom and a hydrostatic plunger for preventing operation of such spring release until the ambient pressure thereon is equal to the pressure at a predetermined water depth.

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SHEET a [1F 4 INVENTOR Asa M. Reece ATTORNEY OCEAN BOTTOM RELEASE DEVICE BACKGROUND OF THE INVENTION This invention generally relates to release mechanisms and more particularly to an automatic release mechanism for placing a load on the ocean'floor in a desired position and for safely releasing such load from a shipboard crane or winch, especially in rough seas.

Release devices of this type are currently used for placing underwater distribution boxes for offshore cables, scientific measuring instruments and the like on the ocean floor. One such device in which the load is supported by a manually operated hook hook requires a pendant or lanyard running back to the boat. This pendant is pulled manually to operate the trip hook. Aside from the disadvantages that use of this device is limited to shallow water, such as 100 feet or less, it has been found that the load can rotate, whereupon the pendant becomes fouled so that release of the load cannot be effected. In addition, the pendant can be pulled inadvertently by the operator or it may become tangled, which in either case is effective to operate the hook prematurely.

In another device, which is automatically operated, the load is held or retaining by a spring in such a manner that when the load comes off the spring, the spring operates to release the load. A problem encountered with this form of release is that the tension on the spring may be reduced during lowering of the load by the motion of the load within the water due to rolling of the boat, from being lowered too fast or from the roughness of the water, whereupon the load is dropped prematurely.

Another present-day automatic release used in an underwater environment is the hydrostatic release, which takes advantage of the increase in pressure at increasing water depths to automatically operate the release. In such cases, however, the device must be preset to release the load at a preselected depth, Inasmuch as the depth of the ocean floor may not be precisely known, and the preset depth must be selected so as to safely insure that such depth will in fact be reached, the load will, upon release, have to free fall from the point of release to the ocean floor. This distance can be considerable because of the lack of knowledge of the depth in which the ship is operating and, as in the aforementioned cases, the load is likely to strike the ocean bottom with such force as to cause damage thereto.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an apparatus for automatically, and in a safe and positive manner, releasing a load on the ocean floor when the load is in a desired position.

Another object of the present invention is to provide a release mechanism which is operable to release a load from a shipboard crane or winch only after the load has touched the ocean bottom.

Still another object of this invention is to provide an inexpensive and automatic release mechanism which is undisturbed by rough seas and is operative to release a load only after a particular depth has been reached and only after such load comes to rest on the ocean floor.

A further object of this invention is to provide an inexpensive, simple, sure, safe and efficient mechanical device which will operate well in any depth of water to release a load being lowered from a shipboard crane or winch only after such load comes to rest on the ocean floor.

The foregoing and other objects are attained by a release mechanism combining a spring-operated release for a shacklesupporting load and a hydrostatically operated release for preventing actuation of the spring operated release until a predetermined water depth has been reached. The springoperated portion supports the load against the biasing pressure of a spring until the load is placed on the bottom. When the load comes off the spring, a ball-type latch is operated by the spring to release toe load.

BRIEF DESCRIPTION OF THE DRAWINGS Still other objects and many of the attendant features and advantages of the present invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like or corresponding parts are indicated by like reference numerals throughout the several views and wherein:

FIG. 1 is a perspective view of a release mechanism formed in accordance with the teachings of the present invention and shown supporting a load from a shackle member thereon;

FIG. 2 is a central sectional view of the release mechanism in an unloaded condition;

FIG. 3 is another central sectional view of the release mechanism in a loaded state with a manual safety pin positioned therein as it appears immediately prior to being lowered into the water; and

FIG. 4 is another sectional view of the release mechanism with the manual safety pin removed therefrom and shown after the hydrostatic safety release has been actuated.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring now to the drawings wherein like reference characters identify corresponding parts throughout, and more particularly to FIG. I whereon, is shown a housing 10, preferably constructed of steel or some other suitable metallic material, having an eye portion 11 formed at one end thereof for receiving a supporting and lowering cable or line 12 and carrying at its other end a weight or load 13 to be placed on the ocean floor, being suspended from the housing 10 by a shackle member 14 which is releasably secured to the housing in a manner to be set forth hereinbelow.

As more clearly shown in FIG. 2, a piston member generally indicated by the numeral 15 is slideably disposed in an elongated axial bore 16 formed in the load supporting end 17 of the housing 10. For purposes of assembly and installation, the piston 15 is formed from an upper portion having a piston head 18 of substantially thesame cross section as the bore 16 and having an integral piston rod 19 of reduced cross section at one end thereof, a lower piston head 20 of substantially the same cross section as that formed by the bore 16 and having a rod portion 21 of reduced cross section at one end thereof and a rod portion 22 of further reduced cross section at the other end of rod 21, which is adapted to be received in a bore 23 in the end of piston rod 19, and a pin 24 of steel or the like passing through aligned transverse apertures in the rod 19 and the rod 22 for locking the upper and lower portions thereof together.

Another pin 26 in the housing 10 is received in a longitudinal slot 27 in the rod portion 21 of the lower portion of the piston 15. This slot 27 permits limited movement of the piston 15 along the longitudinal axis of the housing 10 while preventing the piston from rotating during such movement. A compression spring 28 is disposed over the

piston rods

19 and 22 between the piston head 18 and the pin 26. The normal action of the spring 28, therefore, is to urge the piston member 15 in the direction of the bottom of the bore hole 16 in the housing 10.

When so disposed, with the pin 26 being received in the slot 27 and biased against the lower end thereof the piston 15 is held at its point of maximum travel permitted toward the bottom of the bore 16, and a transverse hole 30 formed in the piston head 20 of the lower portion of the piston member 15, substantially perpendicular to the slot 27 therein,-is aligned with a transverse hole 31 of the same diameter which is formed in the lower end of the housing 10. A pair of hardened steel balls 32 having a diameter only slightly less than the radius of the piston head 20 are disposed in the

holes

30 and 31 and retained therein by a pair of flat springs 33 mounted on the outside of the housing 10 by screws 34. The lower ends of the piston head 20 and the housing 10 are also cut with

slots

36 and 37, respectively, which are slightly less in width than the diameter of the steel balls 34, for preventing the balls from falling out, and are disposed at right angles with the

transverse holes

30 and 31.

Attached to the upper end of the housing in any suitable manner such as, by threadable engagement therewith, as shown in the drawings, is a cylindrical housing 39 having a bore 40 therein for receiving in tight-fitting, slideabie relation a piston member 41. The piston 41 sealably engages the bore wall 40 by means of an O-ring 42 disposed thereon and is provided with an integral piston rod 43 projecting toward the open end of the housing 39 to be received in one end of a transverse bore 44 through the sidewall of the housing 10 and opening interiorly thereof into the bore 16. The closed or base end of the housing 39 is provided with a small opening into which a watertight screw 45 is threadedly engaged.

Another small hole 47 is drilled transversely through the housing 10 parallel to and only slightly below the bore 44. The piston head 18 of the upper portion of the main piston member is drilled with a similar-sized hole 48 which is alignable with the hole 47 in the housing 10 when the device is in the loaded condition, such as illustrated in FIG. .3. An elongated pin member 49 may be loosely fitted in the

holes

47 and 48 when they are so aligned, thus providing a manually operated safety device with the release mechanism before it is ready to be lowered into the water.

In practice, and referring particularly to FIG. 2 wherein the release mechanism of the present invention is shown without a load, the hydraulic piston 41 and its rod extension 43 are withdrawn from the bore 16 so that movement of the piston member 15 in the direction of the bottom of the bore 16 is not blocked thereby. Also, in this condition, it may be seen that the piston member 15 is held in the position of its deepest penetration into the bore 16 permitted by the engagement of the pin 26 with the slot 27 by the biasing force of the spring member 28, in which position the piston head 18 lies at least partially within the path defined by the traverse bore 44 through the housing 10. The

holes

30 and 31 in the piston head and the housing 10 are aligned in this unloaded condition and the steel balls 32 are freely rollable therein, the

slots

36 and 37 in the piston head 20 and the housing 10, respectively, being clear of any interfering objects.

In preparing the device for operation, the load or weight 13 is hang from the shackle member 14, the upper portion of which is inserted through the

slots

36 and 37 whereby the piston member 15 is drawn downwardly against the force of the spring 28 to its lowermost limit of travel permitted by the engagement of the pin 26 with the upper edge of the slot 27. This loaded condition is shown in FIG. 3, where it may be seen that the manual safety pin 49 is inserted through the

holes

47 and 48 in the housing 10 and the piston head 18, respectively, to lock the piston member 15 in the position shown. When the piston member 15 is so drawn down, the steel balls 32 are forced together into the hole 30 in the piston head 20, whereby the shackle member 29 is locked in place.

By removing the screw 45, access is provided to one side of the piston 41 for pushing the piston in the direction of the housing 10, whereupon the extension rod 43 thereof extends through the hole 44 and into the cavity 16 to block movement of the piston 15 in that direction.

Upon attaching the load 13 to the shackle member 14 and removing the manual safety pin 49, the device is ready to be lowered into the water. As it is lowered deeper into the water the increase in hydraulic pressure acting on the exposed base of the piston rod 43 through the open end of the bore 44 becomes greater than the atmospheric pressure in the cylindrical housing 39 on the opposite end of the piston head 41 and thereby forces it and the extension rod 43 to withdraw from the cavity 16.

Referring now to FIG. 4, it may be seen that when the piston rod 43 has been withdrawn from the cavity 16, movement of the piston member 15 toward the bottom or base of the cavity 16 is constrained only by the weight of the load 13 on the shackle member 29 acting against the normal biasing force of the spring 28. when the load 13 comes to rest on the ocean bottom, this constraining force disappears and the spring member 28 forces the piston member 15 to move vertically upward toward the base of the cavity 16 until the limit of travel thereof, determined by engagement of the pin member 26 with the bottom end of the slot 27, is reached, at which point the hole 30 in the piston head 20 of the lower portion of the main piston body 15 becomes aligned with the hole 31 in the housing. The steel balls 32 freely move into the aligned

holes

30 and 31 whereby the shackle member 14 and the load 13 suspended therefrom may be pulled free from the release mechanism, which action is readily accomplished through the mere application of an upward pulling force on the supporting cable 12.

Thus, it may be seen that the load cannot be released until the increase in hydraulic pressure has moved the piston member 41 and its rod extension 43 sufficiently to permit the piston member 15 to move from within the cavity 16. The depth at which this hydraulic piston operates to unlock the release mechanism is determined by the relative length of the piston extension rod 43 and the size of the chamber behind the piston head 41. Further sensitivity of the device as to the amount of weight that must come off the unit before the load is permitted to be dropped or released, is determined by the strength of the spring 28.

Obviously many modifications and variations of the invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An underwater weight release mechanism comprising:

A housing having an elongate bore therein;

means releasably secured to said housing for supporting weight therefrom;

means engaging said weight-supporting means including,

a first piston reciprocally disposed within said bore;

spring means urging said first piston to move in a direction opposite to that in which said weight acts;

means defining limits of travel of said first piston in said reciprocal path; and

means cooperating with said housing for releasably securing said weight-supporting means thereto;

and means responsive to ambient water pressure operatively associated with said first piston for preventing movement of said first piston until a pressure equivalent to that occurring at a predetermined depth is sensed thereby.

2. A weight-releasing mechanism according to claim 1, wherein said ambient water pressure responsive means comprises:

a cylinder;

a second piston slideably disposed in said cylinder; and

an extension rod secured to and slidable with said second piston and reciprocably movable in and out of the path of movement of said means engaging said weight supporting means,

said extension rod having one end thereof exposed to the ambient surroundings.

3. A weight-release mechanism according to claim 2 wherein said releasably securing means comprises a ball-lock arrangement.

4. A weight-release mechanism according to claim 3 wherein said ball-lock arrangement comprises:

a transverse bore in said housing;

a transverse bore in said first piston;

at least two balls disposed in said first piston bore;

said bore in said first piston is at the limit of travel in said reciprocable path is urged thereto by a spring means when no weight is supported by said mechanism.

5. A weight-release mechanism according to claim 4 wherein said weight-supporting means comprises a shackle member, and further comprising:

alignable slots in said first piston and said housing in the weight-supporting end thereof and opening into said bores in said first piston and said housing, respectively, 7. A weight-release mechanism according to claim 6 further for receiving therein said shackle member whereby it may comprising:

be maintained therein by Said bans when a a manually removable safety pin engaging said housing and welght supported from said shackle member.

6 A weight release mechanism according to claim 5 said first piston slidably disposed therein for preventing whereby said means defining limits of travel in said reciproca- 23: 2:8 m any dlrecuon wnhm housing of Sam ble path of said first piston further prevent rotation of said 5 pl piston in said elongate bore of said housing.

Claims

1. An underwater weight release mechanism comprising: A housing having an elongate bore therein; means releasably secured to said housing for supporting weight therefrom; means engaging said weight-supporting means including, a first piston reciprocally disposed within said bore; spring means urging said first piston to move in a direction opposite to that in which said weight acts; means defining limits of travel of said first piston in said reciprocal path; and means cooperating with said housing for releasably securing said weight-supporting means thereto; and means responsive to ambient water pressure operatively associated with said first piston for preventing movement of said first piston until a pressure equivalent to that occurring at a predetermined depth is sensed thereby.

2. A weight-releasing mechanism according to claim 1, wherein said ambient water pressure responsive means comprises: a cylinder; a second piston slideably dIsposed in said cylinder; and an extension rod secured to and slidable with said second piston and reciprocably movable in and out of the path of movement of said means engaging said weight supporting means, said extension rod having one end thereof exposed to the ambient surroundings.

4. A weight-release mechanism according to claim 3 wherein said ball-lock arrangement comprises: a transverse bore in said housing; a transverse bore in said first piston; at least two balls disposed in said first piston bore; said bore in said first piston is at the limit of travel in said reciprocable path is urged thereto by a spring means when no weight is supported by said mechanism.

5. A weight-release mechanism according to claim 4 wherein said weight-supporting means comprises a shackle member, and further comprising: alignable slots in said first piston and said housing in the weight-supporting end thereof and opening into said bores in said first piston and said housing, respectively, for receiving therein said shackle member whereby it may be securably maintained therein by said balls when a weight is supported from said shackle member.

6. A weight-release mechanism according to claim 5 whereby said means defining limits of travel in said reciprocable path of said first piston further prevent rotation of said piston in said elongate bore of said housing.

7. A weight-release mechanism according to claim 6 further comprising: a manually removable safety pin engaging said housing and said first piston slidably disposed therein for preventing movement in any direction within said housing of said first piston.