US3783815A

US3783815A - Heavy duty marine anchor

Info

Publication number: US3783815A
Application number: US00220148A
Authority: US
Inventors: R Towne; J Stalcup
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-01-24
Filing date: 1972-01-24
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A large cast low cost anchor construction of high holding power to weight ratio. Specially shaped fluke stiffening ribs permit relatively thin flat flukes in massive anchors and a new aspect ratio of fluke length to shank length in excess of 0.600.

Description

United States Patent [191 Towne et a].

[451 Jan. 8, 1974 HEAVY DUTY MARINE ANCHOR [76] Inventors: Richard C. Towne, 822 W.

' Roderick Ave.; Johnnie V. Stalcup,

3121 Paula St., both of Oxnard, Calif. 93030 22 Filedf Jan. 24, 1972 [21] Appl. No.: 220,148

[52] US. Cl. 114/208 R, 114/207' [51] Int. Cl B63b 21/26 [58] Field of Search 114/208, 208 A, 207,

[56] References Cited UNITED STATES PATENTS 2,674,969 4/1954 Danforth 114/207 2,677,343 5/1954 Shipley 114/208 R Primary Examiner-Duane A. Reger Assistant Examiner-D. C. Butler Attorney-Richard S. Sciascia, J. M. St. Amond and David OReilly [5 7] ABSTRACT 4 Claims, 4 Drawing Figures HEAVY DUTY MARINE ANCHOR STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The invention relates to heavy duty marine anchors and more particularly to a large high strength cast anchor construction which has a high holding power to weight ratio. The present invention is an improvement of our anchor disclosed in U.S. Pat. No. 3,015,299 entitled Mooring Anchor."

Previous anchors have had to be fabricated from flat mild steel plate to develop comparable high holding powers but this type of construction increased the total anchor costs. Also, operation of these anchors in coral or rock bottoms can cause bending of the fluke tips or even failure. Therefore, some of these anchors are limited in operation to sand or mud bottoms. In order to develop strength, previous cast steel anchors had to sacrifice holding power. The very heavy crown and thick fluke design necessary to develop strength in the cast steel anchors limited the burial capabilities and consequently reduced holding power. Weight alone will not substantially increase holding power as tests have shown. One attempt to increase burial capabilities is to provide a fixed angle between the flukes and shank. However, this is not a satisfactory solution because if the anchor should turn over when being lowered to the bottom little holding power is achieved.

SUMMARY OF THE INVENTION The purpose of the present invention is to provide a heavy duty marine anchor, made with cast steel material, having high strength and holding power in coral and rock as well as sand and mud bottoms. The present invention is an improvement of the aforementioned U.S. Pat. No. 3,015,299 which increases the strength per weight and results in a higher holding power to weight ratio. Rounded-molded stiffening ribs which extend to the tips of the flukes along the edges adjacent to the shank permit a construction of cast steel. Further, the high strength cast steel construction made it possible to design the important aspect ratio of fluke length to the shank length to be in excess of 0.600 which further increases the holding power to weight ratio over other anchors. The crown design permits very large anchors to be cast yet retains the high holding power to weight ratio of the smaller size anchors and also incorporates adequate tripping area to insure fluke operation in soft soil bottoms.

New fluke angle adaptors as well as the folding stabilizers disclosed in our US. Pat. No. 3,527,187 are incorporated to also provide the efficient operational characteristics of the smaller anchors. The anchor can be fabricated in very large sizes, (i.e., 20,000 pounds and greater) while retaining many of the advantages of smaller anchors.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a heavy duty marine anchor of cast steel construction having an increased strength and holding power.

Another object of the present invention is to provide a heavy duty marine anchor with relatively flat flukes and increased fluke length to shank length aspect ratio to develop maximum holding power.

Yet, another object of the present invention is to provide a very large anchor with folding stabilizers to facilitate shipping and storing.

Other objects, advantages and novel features will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a general plan view of the heavy duty marine anchor with folding stabilizers. 1

FIG. 2 is a section view taken through 22 of FIG.

FIG. 3 is a section view taken through 3-3 of FIG.

FIG. 4 is an enlarged detail of the fluke angle adaptor indicated by the encircled portion 4 of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 is illustrated the heavy duty marine anchor having a shank 10, a fluke assembly 12, and a pair of folding stabilizers l4.

Shank 10 is of cast construction in a semi-oval or octagon shape in the vertical direction. The vertical dimension is thus slightly greater than the width which provides greater strength and penetrability of the shank itself into the ocean bottom. The shank tapers slightly toward the forward end to which is attached the usual shackle 16 for connecting the anchor to a chain or cable. The base or aft-end of the shank is semicircular in shape as shown in FIG. 2 with a generally horizontal concentric bore provided for receipt of trunnion bar 18. The aft-end of the shank is also provided with generally rectangular vertical extensions or abutments 20 which are slightly forward of a center line through the trunnion bore hole.'The abutments have a horizontal flat surface 22 facing toward the aft-end of the shank. These flat surfaces are constructed to have a fixed angle of about 20 with the vertical. The abutments have been formed with their base portion adjacent the shank having an elongated generally horizontal shaped slot 24 for attachment of fluke angle adaptors as will be more fully described hereinafter. The purpose of the abutments is to provide limiting stops for the rotational movement of the flukes.

One of the most important features of the invention is the unitary homogeneous cast steel construction of fluke assembly 12 which permitted holding power to weight ratios greater than any prior art anchors. The fluke assembly 12 includes flukes 26, fluke stiffening ribs 28, tripping palms 30, tripping palm stiffening webs 32, padeye 34 and a centrally located massive stopper 36 cast from a high strength steel material. The unitary cast steel construction provides greater strength than the welded anchor of our US. Pat. No. 3,015,299. The cast construction also permits the production of very large anchors (i.e., 20,000 pounds and greater) with relatively thin, flat flukes resulting in much greater holding power at lower cost of construction. The an chor of the present invention is stronger, more 'economical to produce and can be fabricated in much larger sizes than the welded anchor design.

The flukes 26 are formed to be generally flat with an ogival edge 38 and a plurality of rounded-molded stiffening ribs 28 provided on either side. In order to increase the strength of the flukes, two of the roundedmolded, stiffening ribs 40 (FIG. 3) are formed along each edge of the fluke adjacent to the shank and extend along the ogival edge to the fluke tips. The fluke stiffen ing ribs 28 converge with the fluke surface short of the fluke tips while the stiffening ribs 40 taper to near convergence at the fluke tips.

The cast steel construction of the fluke arms not only permitted the use of higher strength steel but also permitted the design of stiffener ribs which curve along the ogival edge of the flukes to the tips. This design in addition to reducing the overall thickness of the flukes, which increased the burial capability, also alleviates the problem of bending the fluke tips in coral or rock bottoms. The important aspect ratio of fluke length to shank length has been increased to be in excess of 0.600 because of the high strength of the cast construction. The larger aspect ratio facilitates the increase in V holding power in very large anchors.

Joined to the aft-end of the flukes are tripping palms 30 formed to meet at the base of the flukes and have an included angle of 100. A trunnion bar bore hole 19 for attaching fluke assembly 12 to the shank is provided at the junction of the tripping palms 30. The tripping palms are strengthened with a plurality of stiffening webs 32 which can be more or less than the five shown if desired. The center stiffening web is formed with a padeye 34 which can be used to withdraw an anchor buried in a sand or mud bottom by attaching an additional chain or cable. The area of the tripping palms should be between 80 percent to 100 percent of the area of one of the flukes. I

The central stiffening web also has a very thick massive portion formed to provide a stopper surface 42 as shown in FIG. 2. The massive stopper has a semicircular portion 44 conforming to the aft-end of the shank 10. The flat stopper surfaces 44 have an area greater than the flat area on abutments and together form an included angle of approximately 120. This means that with the flukes parallel to the axis of the shank the flat stopper surfaces 44 form an angle of approximately with the vertical. These massive stopper surfaces cooperate with the shank abutments to limit rotation of the flukes to 50 on either side of the shank 10.

An additional feature of the present invention is the improved construction of detachable fluke angle adaptors 46 as shown in FIG. 4. The fluke angle adaptor has a toe portion 23 constructed to fit into the shaped elongated slot 24 of the shank abutment. Two counterbored bolt holes are provided in the adaptor and correspond to similar holes in the shank abutment. The improved fluke angle adaptor can withstand much greater stresses than before because toe portion 23 reduces the shear forces which could sever the attaching bolts. The adaptor is flush fitting against the 20 degree angled face 22 of the shank abutment 20 and has a rearward face 48 which has an angle of about 5 to the vertical when attached. These adaptors thus limit the twin fluke rotation to approximately which tests reveal is the best angle for use on sand bottoms. With the adaptors re moved the twin flukes can rotate to about 50 which is the optimum angle for mud bottoms and is also suitable for coral or rock bottoms.

A pair of folding stabilizers 14 is attached to the outer edges of the twin flukes. A detailed description of the manner of constructing, attaching and operating the stabilizer arms is shown in our US. Pat. No. 3,527,187 and therefore will not be repeated here.

Thus there has been disclosed an improved cast anchor construction for very large anchors which provides flatter, stronger flukes with increased holding power to weight ratio. Obviously, many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is:

l. A heavy duty marine anchor comprising:

a shank having a shackle in its forward end, a semicircular aft-end with a concentric trunnion bar receiving bore and vertically extending integrally formed abutments having a flat surface facing toward the aft-end and slightly angled toward the forward end, each of said shank abutments having a shaped slot at its rearward base portion adjacent to the shank;

a unitary homogeneous cast steel fluke assembly disposed on either side of said shankcomprising;

a pair of generally flat flukes each having an ogival edge and a plurality of rounded-molded stiffeners on either side, two of said stiffeners formed along the inside edge of said flukes adjacent to the shank and extending along the ogival edge to near convergence at the tips;

a pair of tripping palms with their main sides meeting at the base of the flukes and having a trunnion bar receiving bore with the opposite sides forming an included angle of 100 and a plurality of stiffening webs joining said opposite sides;

centrally located massive stopper means formed between the opposite sides of said tripping palms and adapted to cooperate with the shank abutments to limit the fluke rotation to 50 on either side of the longitudinal axis of said shank;

detachable fluke angle adaptor means for attachment to said shank abutments for limiting fluke rotation to 35, said detachable fluke angle adaptors having a toe portion for engaging said shaped slot when attached;

a trunnion bar extending through said fluke bore and said shank bore for pivotally supporting said fluke assembly about the aft-end of said shank; and

stabilizing means attached to said fluke assembly.

2. The heavy duty marine anchor of claim 1 wherein the tripping palm area is between percent and percent of the area of one fluke.

3. The heavy duty marine anchor of claim 2 wherein the fluke length to shank length aspect ratio is greater than 0.600.

4. The heavy duty marine anchor of claim 3 wherein said stabilizing means are folding stabilizers attached to the outside edge of said flukes and capable of being extended to lie substantially along the axis of said trunnion bar.

Claims

1. A heavy duty marine anchor comprising: a shank having a shackle in its forward end, a semicircular aftend with a concentric trunnion bar receiving bore and vertically extending integrally formed abutments having a flat surface facing toward the aft-end and slightly angled toward the forward end, each of said shank abutments having a shaped slot at its rearward base portion adjacent to the shank; a unitary homogeneous cast steel fluke assembly disposed on either side of said shank comprising; a pair of generally flat flukes each having an ogival edge and a plurality Of rounded-molded stiffeners on either side, two of said stiffeners formed along the inside edge of said flukes adjacent to the shank and extending along the ogival edge to near convergence at the tips; a pair of tripping palms with their main sides meeting at the base of the flukes and having a trunnion bar receiving bore with the opposite sides forming an included angle of 100* and a plurality of stiffening webs joining said opposite sides; centrally located massive stopper means formed between the opposite sides of said tripping palms and adapted to cooperate with the shank abutments to limit the fluke rotation to 50* on either side of the longitudinal axis of said shank; detachable fluke angle adaptor means for attachment to said shank abutments for limiting fluke rotation to 35*, said detachable fluke angle adaptors having a toe portion for engaging said shaped slot when attached; a trunnion bar extending through said fluke bore and said shank bore for pivotally supporting said fluke assembly about the aft-end of said shank; and stabilizing means attached to said fluke assembly.

2. The heavy duty marine anchor of claim 1 wherein the tripping palm area is between 80 percent and 100 percent of the area of one fluke.