US3024756A

US3024756A - Anchor with hinged crown section

Info

Publication number: US3024756A
Application number: US77373A
Authority: US
Inventors: Robert D Ogg
Original assignee: Eastern Co
Current assignee: Eastern Co
Priority date: 1960-12-21
Filing date: 1960-12-21
Publication date: 1962-03-13
Anticipated expiration: 1979-03-13

Description

March 13, 1962 R. D. OGG 3,024,756

ANCHOR WITH HINGED CROWN SECTION Filed Dec. 21, 1960 2 Sheets-Sheet 1 IN VEN TOR.

W BY

J ATTOPA/EKS March 13, 1962 R. D. 066 3,024,756

ANCHOR WITH HINGED CROWN SECTION Filed Dec. 21. 1960 2 Sheets-Sheet 2 Ql lj ii -TIE; ,1 INVENTOR.'

A TTORWE K5 United States atent tice 3,024,756 ANCHOR WITH IIINGEI) CROWN SECTION Robert D. tigg, Portland, Maine, assignor to The Eastern Company, a corporation of Connecticut Filed Dec. 21, 1960. Ser. No. 77,373 7 Claims. (Cl. 114-208) This invention relates to an improved ships anchor of the twin fluke type, particularly anchors constructed in accordance with any one or more of Patents 2,249,546; 2,282,566; 2,320,966; 2,567,390; 2,641,215 and 2,643,631.

The so called twin fluke anchor includes a shank and twin flukes, usually secured together as a unit and pivoted at one end of the shank whereby both flakes engage the ground simultaneously. The anchor may include a stock at either end of the shank although it is common to pivot the shank on the stock so the latter is provided at the after end of the shank. Anchors of this type are known as having an extremely high holding power per pound of weight. For example, when such an anchor is engaged with a good sound bottom, it is not infrequently found that the anchor will hold several thousand times its own weight.

When such an anchor is cast overboard and is permitted to fall upon bottom, the pull provided by the attached anchor line or cable draws the anchor over the bottom. To ensure that the flukes engage bottom positively and without too much loss of time, it is usual to provide at the after end of the anchor, a structure which facilitates movement of the flukes into operating position and ensures their rapid and positive engagement with the bottom. This structure, usually termed a crown, has included arrangements of both arcuate and plane surfaces extending upwardly more or less directly from the plane of the Ilukes for a considerable distance above such plane. It is the function of these surfaces to ensure that the anchor engages bottom promptly and that the flukes are moved relative to the shank into their final operative position.

In Patent 2,641,215 the crown of such a twin fluke anchor is described in considerable detail. It is said to be a particular advantage of that anchor that it would engage a bottom promptly when drawn over the bottom and would not fioat." When an anchor floats, the flukes lie fiat on the bottom surface or are even inclined upwardly and do not fall into operating position even though the anchor is drawn over the bottom for considerable distance. Floating occurs most frequently in a soft mud bottom. In fact, it is in a bottom of this characteristic that the greatest ditficulty is encountered in securing the engagement of a twin fluke type anchor. This is because if such an anchor is designed to operate satisfactorily on a hard sand bottom it generally will not engage promptly in a soft mud bottom. Many harbors and rivers throughout the world carry so much silt that effecting a proper anchorage is a matter of some dithcnlty. In many instances, the bottom will contain a fluid mixture of silt and water of such low density that it is ineffective in offering much more resistance to the movement of the anchor than water itself and, as a consequence. an anchor designed to function properly in hard sand is merely drawn through this fluid mass ineffectivcly.

The anchor of the present invention is particularly characterized by its ability to function satisfactorily in either type of bottom, that is, it possesses the necessary characteristics for functioning satisfactorily in a soft mud bottom as well as in a good hard sand bottom. To achieve this, the anchor possesses a crown structure including dual crown-plates mounted on each side of the anchor, one of each of the dual plates being movable with respect to the other whereby, upon engagement with a soft bottom, the flukes are rotated into engaging position promptly and effectively. If the anchor transverses the soft portion of the bottom and becomes engaged with hard sand, then one of the dual plates is moved into a second position in which it provides the crown characteristics necessary to ensure proper engagement of the anchor in a hard sand bottom.

A further feature of the anchor of this invention is its ability to rid itself of soft clinging mud by reason of the novel crown construction.

It is in general the broad object of the present invention to provide an improved twin fluke anchor construction in which a crown is provided having dual crownplates on each side thereof, one of each of the dual plates being movable with respect to the other whereby the crown characteristics initially provided are suited to the engagement of the anchor in a soft bottom, these characteristics changing automatically as the anchor is moved into engagement with a firmer bottom.

The invention includes other objects and features of advantage, some of which, together with the foregoing will appear hereinafter wherein the present preferred form of anchor is set forth.

In the drawings accompanying and forming a part hereof, FIGURE 1 is a side elevation showing an anchor constructed in accordance with this invention; the full lines show the anchor as it appears when engaged in hard bottom, while the dotted line shows the anchor as it appears free of any bottom engagement or in a soft bottom.

FIGURE 2 is a top plan view of the anchor with the fiukes extended in the same plane as the shank.

FIGURE 3 is an enlarged fragmentary view of the crown.

FIGURE 4 is an enlarged fragmentary view looking at the rear of the anchor and showing the construction of one of the dual crown-plates.

The anchor of the present invention includes a shank 6, a pair of substantially like symmetrical flukes 7 and 8 disposed on opposite sides of the shank. A stock 9 is extended between the fiukes 7 and 8 and the three are joined together as by welding into a suitable unit, the shank being mounted between the flakes and pivotally supported on the stock 9. Each fluke includes a rib 11 extending along its inner edge adjacent to the stock. Extending transversely of the plane of the flukes are spacer plates 14. the spacer plates extending above the plane of the fiukes a short distance. Mounted upon the spacer plates on each side of the flukes are dual crown-

plates

16 and 17 joined together by a hinge 18. Each crownplate 17 is fixed in position on the spacers and extends forwardly over the fiukes at a small acute angle, e.g. 5 to 25, while crown-platcs I6 is urged by a spring 19 into a vertical position in which it stands upwardly in respect to the plane of the tlukes at an angle of approximately 80 to such plane. Any further movement of the movable plate 16 toward the flakes is limited by the construction of the hinge 18. The springs 19 are supported upon a pin 21 passed through the spacer plates. One end of the spring 19 bears against the back of a plate 16 while the other end of the spring is carried in a clip 22 mounted on the side of a spaced plate.

Normally, the movable crown-plates each stand outwardly at an angle of from about to about to the plane of the fiukes as is shown in FIGURE 1. Thus, in the normal position of engagement of the anchor in soft bottom, as is shown in dotted lines in FIGURE 1, both movable plates 16 stand out at this angle to the plane of the flukes. The pressure applied by the spring 19 is such that the plates are maintained in this position unless and until the anchor comes into engagement with a bottom of such consistency that sutficient pressure is applied to move the plates against the bias of the springs into the full-line position in which the plates are shown in FIG- URE 1. Thus, the described anchor is such that it functions effectively in either a soft or hard bottom, adjusting and suiting itself to the characteristics of the bottom engaged.

As is set forth in Patent 2,641,215, in the preferred form of anchor the crown-plates are preferably positioned so that from 20% to 50% of the area of each dual crownplate is forward of the stock, the preferred value being 35% and the preferred range, 25% to 45%. Each dual crown-plate is disposed fore and aft of the pivot and should preferably be of an overall length equal to 19% of the shank length, the preferred range being 15% to 23% and in any case the preferred overall length between 10% and 28% of the shank length; in the anchor shown in the drawing, the shank length is the distance from the center of the cable attachment eye to the center of the stock.

Each fixed-crown plate 17 preferably slopes upwardly and away from the plane of the iiukes at a relatively small acute angle, preferably 14 and preferably one within the range of 9 to 19 and in any case between 5 and 24. Also, each dual crown plate must, for best results, be spaced from the center line of the pivot (measured in a direction substantially normal to the plane of the flukes) a distance equal to between 8% and 10% of the shank length, the prefererd distance being in the range of from 5% to 14%, and in any case, within the range of 3% to 16%; when the stock acts as the pivot mounting for the flukes, the stock center line or longitudinal axis can be utilized in making this measurement.

In addition, I prefer that each plate 16 provide at least about 40% of the total area of the crown-plates and preferably from 50% to 75% of such total area of the

plates

16 and 17.

I claim:

1. An anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of flukes pivoted at the after end of the shank with the shank between the flukes, said fiukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown including a pair of substantially flat crown-plates, each crown-plate being supported in the position wherein said crown-plate is spaced from the plane of the flakes, each crown-plate includes a forward and after portion, the two portions being hinged with respect to each other, the after portion being movable with respect to the flukes between a first position in which the movable plate stands at an angle of from about 70 to about 80 to the plane of the flukes and a position in which said plate is substantially parallel to the forward portion.

2. In an anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of flukes pivoted at the after end of the shank with the shank between the flukes, said flukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown including a pair of substantially flat crown-plates, each crown-plate being supported in a position wherein said crown-plate is spaced from the plane of the fiukes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the flukes, of between about 3% and about 16% of the shank length with each crown-plate sloping upwardly and rearwardly away from the plane of the flukes and being supported to permit bottom to flow freely between the fluke and the underside of the crown-plate, each crown-plate having a width greater than about 5% of the shank length and a length of from about 10% to about 28% of the length of the shank and being positioned with between about and about 50% of its area forward of the pivot, each crown-plate including a forward and after portion, the two portions being hinged with respect to each other, the after portion being movable with respect to the flukes between a first position in which the movable plate stands at an angle of from about 70 to about to the plane of the flakes and a position in which said plate is substantially parallel to the forward portion.

3. In an anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of ilukes pivoted at the after end of the shank with the shank between the fiukes, said flukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown at the after end of the shank including a pair of substantially fiat crown-plates, and a thin fiat plate extending vertically to the plane of the fiukes and parallel to the shank and supporting each crown-plate in a position wherein each crown-plate is spaced from the plane of the fiukes a distance, measured outwardly from the center line of the stock and at substantially to the plane of the flukes, of between about 3% and about 16% of the shank length and with the crown-plate sloping upwardly and rearwardly away from the fiukes at an angle of from about 5 to about 24 to the plane of the fiukes, each crown-plate having a width of between about 5% to about 17% of the shank length and a length of from about 10% to about 28% of the length of the shank, each crown-plate including a forward and after portion, the two portions being hinged with respect to each other, the after portion being movable with respect to the flukes between a first position in which the movable plate stands at an angle of from about 70 to about 80 to the plane of the fiukes and a. position in which said plate is substantially parallel to the forward portion.

4. In an anchor of the twin fluke type having a shank with a forward and after end, a stock, a pair of flukes pivoted at the after end of the shank with the shank between the flukes and movable therebetween in a plane normal to the flukes, said flukes having faces thereon substantially simultaneously engaging the ground in operative position; a crown at the after end of the shank including a pair of substantially fiat crown-plates, each crown-plate being supported in a position wherein said crown-plate is spaced from the plane of the fiukes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the fiukes of between about 3% and about 16% of the shank length with the crown-plate sloping upwardly and rearwardly away from the fiukes at an angle of from about 5 to about 24 to the plane of the flukes to permit bottom to flow freely between the fluke and the underside of the crown-plate, each crown-plate having a length of from about 10% to about 28% of the length of the shank and a width greater than about 5% of the shank length and being positioned with between about 20% and about 50% of its area forward of the pivot; the improvement comprising each crown-plate including a forward and after portion, the two portions being hinged with respect to each other, the after portion being movable with respect to the flukes between a first position in which the movable plate stands at an angle of from about 70 to about 80 to the plane of the fiukes and a position in which said plate is substantially parallel to the forward portion.

5. In an anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of flakes pivoted at the after end of the shank with the shank between the ilukes, said fiukes having faces thereon substantially simultaneously engaging the ground in operative position; a crown at the after end of the shank including a pair of substantially flat crown-plates, each crown-plate being supported centrally of the fiukes and in a position wherein said crown-plate is spaced from the plane of the flakes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the flukes, of between about 3% and about 16% of the shank length with each crown-plate sloping upwardly and rearwardly away from the plane of the flukes, each crown-plate having a width greater than about of the shank length and a length of from about to about 28% of the length of the shank; the improvement comprising each crown-plate including a forward portion fixed relative to the flukes and an after portion hinged with respect to said forward portion and to the fiukes.

6. An anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of fiukes pivoted at the after end of the shank with the shank between the flukes, said flukes having faces thereon substantially simultaneously engaging the ground in operative position; the improvement comprising a crown including a pair of substantially flat crown-plates, each crown-plate being supported in the position wherein said crown-plate is spaced from the plane of the flukes, each crown-plate includes a forward and after portion, the two portions being hinged with respect to each other, the after portion being movable with respect to the fiukes between a first position in which the movable plate stands at an angle of from about 70 to about 80 to the plane of the flukes and a position in which said plate is substantially parallel to the forward portion providing at least about 40% of the total area of the crown-plates.

7. In an anchor of the twin fluke type having a shank with a forward and an after end, a stock, a pair of fiukes pivoted at the after end of the shank with the shank between the flukes, said fiukes having faces thereon substantially simultaneously engaging the ground in operative position; a crown at the after end of the shank including a pair of substantially flat crown-plates, each crown-plate being supported centrally of the fiukes and in a position wherein said crown-plate is spaced from the plane of the fiukes a distance, measured outwardly from the center line of the stock and at substantially 90 to the plane of the flukes, of between about 3% and about 16% of the shank length with each crown-plate sloping upwardly and rearwardly away from the plane of the fiukes, each crown-plate having a width greater than about 5% of the shank length and a length of from about 10% to about 28% of the length of the shank; the improvement comprising each crown-plate including a forward portion fixed relative to the fiukes and an after portion hinged with respect to said forward portion and to the flukes, the forward portion providing at least about of the total area of each crown-plate.

References Cited in the file of this patent UNITED STATES PATENTS 2,576,390 Danforth Nov. 27, 1951 2,641,215 Danforth June 9, 1953 2,643,631 Danforth June 30, 1953