US2368942A - Anchor - Google Patents

Description

Feb.6, 1945. .1. K. NORTHROP ANCHOR Filed Aug. 20, 1940 INVENTOR, JOHN k. NORTHROP.

By QM G'W ATTORNEYS.

Patented Feb. 6, 1945 UNITED. STATES PATENT OFFICE ANCHOR John K. Northrop, Los Angeles, Calif. ApplicationAugust 20-, 1940, Serial, No. 353,352 11 Claims. (cil a-20s) Myinventlonrelates toanchors, and more'particularly to an anchor which :is adapted to enter :penetrable bottom substantially independently of .the Weight of the-anchor.

, Among the objects .ofmy invention are, topro- 1 vide a lightweight anchor -;capab1e of penetration in bottom, due .to theplaningcharacteristics of the fluke; to provide an anchorof'light weight, having a high molding power;-to provide a single fluke anchor of the-swinging fluke-type which will not rotate out of bottom during, or after penetration intotheibottom; :to provide an anchor having a holding powerzsubstantially independent of anchor weight, having both a planing fluke, and a planingystock; 'to'provide a single- ,fluke type anchor having a holding power substantially independent-of weight; to provide a means and method of' preventing asinglefluke anchor :from rotating during, and after penetration into the bottom.

In Patent No. 2,075 ,82'L-issued April 6, 1937,1120 myself and Harry M. Gesner, We have described and claimed an anchor penetrating bottom and holding therein substantially independently of the weight of the anchor, because of the angular relationships offthe fluke to bottom "when the anchorfirst' rests on bottom, during penetration, and after full'engagementwiththe bottom. The prior anchor, however, had a fluke fixed 'with relation to the shank and the present invention is directed toward an anchor havingsimilar planing characteristics in .penetrable bottom with,

however, a structure embodying .a single pivoted fluke, together with means to assure proper penetration in thebottomwithoutrotation.

Anchors of the single fluke type have a tendency, during penetration and thereafter, torotate, and in many cases such a rotation will occur in spite of the use of :a stock,particularly if the stock is of such section as to aid in the progression of the anchor into bottom. This'rotation may be of such magnitude that the anchor fluke Will completely emerge from the bottom, and thereby destroy the holding "power of the anchor. for preventing, rotation of the "anchor, even though a planing type stock .i used.

In all anchors of the type where penetration is substantially independent of Weight, it is highly desirable that the shank of the anchor be of :such section that it may'readily-progress downward into penetra'ble bottom in order that the anchor may become deeplyembedded. For a like The present invention provides, means resistance to forward movement of the anchor and it is also desirable that this stock either offer minimum resistance to downward motion of the anchor in bottom, -or actually aid'in the downward motion. ,The contour of Ta; stoclghowever,

which offers little resistance to 'forward and downward motion of the anchor in bo'ttom isgnot the contour favorableto proper stock action, i. e.,

ficient ,to prevent the'fluke from rotating out :of

bottom.

Myv invention may be more-readily understood by direct "reference to the drawing wherein:

Fig. 1 is the sideiview of a form of my inven-, tion embodying a swinging fluke having angular relationships to the shank giving the anchor-the ability *to penetrate the bottomsubstantiallyin a dependent of weight.

' of pivot bolts 6,;the front portion of each arm ,Fig. 2 is a top view of the anchor shown-in Fig.

1, withthe fluke centralized.

Fig. 3 is a top view ofan anchor'having amodified drag member on the ends ofthe stock.

Fig. 4 is a fragmentary sideyview'showing the drag member used'on theanchor-of Fig. 3.

Referring to Figs. land 2, ashank I is formed of spaced frame members v2 and 3, these frame members converging at one'end thereof to a junction 4, this junctionbeing provided'witha cable -ring 5, to which the anchor cable may be at.-

tached leading to a vessel or aircraft. Before convergence, the frame members! and 3 are par- .allel and their opposite extremities are provided .with pivot bolts 6 to whichfluke arms 'I are hinged. Fluke arms I extend both front and rear being longer than the rear portion thereof.

Joining the longerportions of fluke arms I is a planar fluke 8, of thinsection and extended area, the arm joints 9 being preferably welded. Fluke 8 is provided with a pointed bottom penetrating end 10, and this pointed end is protected with a penetration tip ll applied thereto, The edges'of end ilflcare preferably sharpen'ed-.

The opposite ends of thefiuke arms I on the other side of pivot bolts *5 are joined-bye. planar stock 12 passingthrough each arm, this stock "being heldin positionyby stock pins 13.. Stock l2 extends laterally beyond fluke arms 1, preferably equidistant on both sides thereof. I pre- 'members solidly riveted or otherwise attached to the ends only of stock l2 on both upper and lower surfaces. Such members provide an increased drag only at'theouter ends of the stock;

I have found that such increased drag, even. though small compared to the drag of a stock having an entire contour similar to that of the drag members is sufiicient to prevent rotation ends, the main object being the provision of a member increasing the drag of the stock only adjacent the ends thereof.

In operation the anchor is, of course attached to its cable and thrown overboard from the vessel or craft it is desired to anchor. Uponreaching bottom, the shank thereof will, due to its shape, tend to lie flat on the bottom. Two fluke conditions may occur. Either the ends 11 of brackets IE will penetrate the-bottom and allow the fiuketo lie generally flat on the bottom or, ifthe ends I! cannot enter fully, they will rogtate the fluke upwardly. However, in either case the first forward movement of the anchor causes the drag on the ends ll to rotate the fluke so 7 that the, point thereof is presented to bottom during'penetration, as will be explained later.

The swing of fluke arms I and attached fluke 8 with relation to shank l is controlled by fluke arm brackets l6 applied to fluke arms 1, these bracketsbeing provided with laterally extending portions l1 engaging shank members 2 and 3 after the fluke arms have assumed a predetermined angle with shank I.

As set forth in Patent No. 2,075,827, issued April 6, 1937, to myself and Harry M. Gesner, the fluke angle just before, during, and after penetration, is very important to insure proper penetration and holding power thereafter of a light weight anchor, 'such holding power of course, being increased by complete bottom pene: tration of the anchor, including penetration of the shank and in many cases of the stock. It is always desirable tohave the forward pull of the anchor cable tend to embed the anchor more and more'under the cable pullinstead of drag ging'the anchor directly forward. I have found that when a fluke of thin section and relatively large area, with the fluke arms, and fluke length so proportioned tothe length of the shank that the center of area of the fluke" when registering with the bottom during penetration thereof, assumes a planing angle of substantially 45 to bottom, that maximum planing ability for bottom penetration substantially independent of weight is developed. I have also found that good initial penetration of the fluke occurs when the -fluke is presented to the bottom. with the plane of the fluke making an angle to the bottom plane of not substantially over 60, and preferably between 50 and 60.- I have alsofound that the fluke will hold with maximum holding power when fully embedded when the fluke plane is held to an angle with the shank plane within" a range of from 25 to 35, apreferred angle be- I have found, however, that it is pos maintained when the center of area of the flukej registers with the bottom plane. The approximate center of area of 'a fluke of a particular shape is easily determined by inspection, and the 1 65 In the modification shown in Figs. 3 and 4, a

actual center of area is easily calculated.

drag member comprising a disc is attached to each end of the stock by afiexible link, preferably a chain 2|, otherwise the anchor is the same as the modification formerly described.

Other fixed or flexibly attached drag members will, of course, suggest themselves to those skilled in the art, and I do not wish to be limat an anglewhich causes it to start penetration and engagement with the bottom. The fluke then continues to penetrateand rotate until the final angle to the shankis reached, as determined by the restrictive engagement of ends ll with theshank members-5 a V The point'of the fluke therefore-under the I forward pull catches in bottom and the anchor jack-Knifes on pivot 6 until the anchor rests on the bottom at three points, cable attachment 5,

fluke point 1 Land oneof the drag members 15 on stock l2. *It is to be noted that'so far as the drag .efiiciency. of the stock is concerned, the 'drag exerted by the stock in this position is fully equivalent to any drag that would be exerted by a stock having an overall section similar to the section of drag member. 15 Continued forward pull then progresseslthe fluke into'bottom with it maximum angle to the shank as determined by bracket l6- Any tendency for the fluketo rotate is counteracted by the drag of the drag members when the fluke has penetrated bottom until the center of area of the 'fluke'registers with the bottom plane, the fluke assumes a 15 angle thereto and maximum planing action occurs. The anchor then rapidly progresses'into the ground under the cable pull. As the spaced ited to any particular type or shape or mode of attachment of the drag members to the stock shank members reachbottom they penetrate the ground readily because they present their narrowest section to the bottom. Asthe stock approaches the bottom plane and enters it, the stock itself also planes into the ground, as it-is in coplanar relationship .to the fluke.

As the anchor embeds itself, the drag members l5 offer relatively much smaller resistance to forward and downward progression than if the entire stock had the same section. If, after embedding in the bottom there is any tendency for the anchor to rotate, one of the embedded members may emerge from the bottom plane leav ing only the other drag member in the bottom. Thisunbalan'ce of drag will then tend to stop further rotation and to straighten out the anchor.

In the device shown in Figs. 3 and 4,- the drag members are flexibly attached to th ends of the stockby chain 2| and in this case the stock may be embedded well below the bottom, plane with the drag members above the bottom plane. Any rotational tendency of the anchor will then cause one of the drag members to engage the bottom with the other drag member lying on top ofthe bottom. In this case the drag, being wholly 'on one side of the stock, will straighten out the rotation. If, however, the anchor has been emabove the stock level. Under these conditions, the first tendency of thestock to rotate will continue the drag on one member, whereas any upward movement of the stock on the opposite side will tend to take the strain off the attached drag member, thus unbalancing the drag and straightening out the anchor. The loose attachment of the drag members therefore allows embedding of the complete anchor without the embedding of the drag members. Thus the drag members do not oppose complete submergence of the anchor in bottom, yet are always ready to combat rotation.

It will, therefore, be clear that I have provided an anchor having a pivoted fluke operating within a shank frame which will penetrate independently of weight and which has completely solved the problem of single fluke anchors of the Navy type operating within a frame, i. e., the problem of rotation, and that I have solved this problem by providing lumped drag stresses at the outer ends of the stock in such a position with relation to the anchor that the drag becomes unbalanced the moment any rotation of the anchor occurs,

this unbalance immediately tending to stop the pair of spaced fluke bars each pivoted adjacent the other end of a frame bar-t0 swing inside of and adjacent said frame bars and extending on both sides of said pivot, means for limiting the swing angle of said fluke bars relative to said frame bars, a substantially planar thin section fluke joining end portions of said fluke bars, a substantially planar thin section stock bar join.

ing and extending laterally in substantially the plane of said fluke beyond the opposite end portions of said fluke bars on the other side of said pivot, and drag members attached to the outer ends of said stock-bar spaced from said frame bars and shaped to materially increase the effective resistance of said stock-bar ends to penetration of ground.

2. In an anchor comprising a shank, a fluke attached adjacent one end of said shank, a stock extending laterally adjacent the attachment of said fluke to said shank, and a pair of freely depending drag members one flexibly attached to' each end of said stock.

3. In an anchor comprising a shank, a fluke attached adjacent one end of said shank, a stock extending laterally adjacent the attachment of said fluke to said shank, and a pair of freely depending drag members one attached to each end 'of said stock by a flexible link.

4. In an anchor comprising a shank, a fluke attached adjacent one end of said shank, a stock extending laterally adjacent the attachment of said fluke to said shank, and a pair of freely depending drag members one attached to each end of said stock by a chain.

5. An anchor having a shank member, a fluke arm member pivoted adjacent one end of said shank member and extending in both directions from said pivot, a substantially planar thin section fluke attached to said fluke arm member on one side of said pivot, and a laterally extending planar stock attached to said fluke arm on the opposite side of said pivot, said stock and said fluke being substantially coplanar in all positions of said fluke and stock.

6. An anchor having a shank member, a fluke arm member pivoted adjacent one end of said shank member and extending in both directions from said pivot, a substantially planar thin section fluke attached to said fluke arm on one side of said pivot, and a laterally extending planar stock attached to said fluke arm on the opposite side of said pivot, said stock and said fluke being substantially coplanar and of substantially 'the,

arm member pivoted adjacent one end of said shank member and extending in both directions from said pivot, a substantially planar thin section fluke attached to said fluke arm member on one side of said pivot, and-a laterally extending planar stock attached to said fluke arm on the opposite side of said pivot, said stock and said fluke being substantially coplanar, a freely depending drag member flexibly attached to each end of said stock.

9. Apparatus in accordance with claim 1 wherein said drag members are flexibly attached to the ends of said stock-bars.

10. An anchor adapted to penetrate in bottom substantially independent of weight, having a shank, a cable attachment at one end of said shank, a holding and planing member pivoted adjacent the other end of said shank, said member having thin substantially coplanar planing portions of substantially the same thickness on each side of the axis of rotation of said member, one of said portions extending radially from said pivot to act as.a fluke, the other portion being extended in' an axial direction relative to said pivot to act as a stock.

11. An anchor adapted to penetrate in bottom substantially independent of -weight having a shank, a cable attachment at one end of said shank, a holding and planing member pivoted adjacent the other end of said shank, said member having thin substantially coplanar planing portions of substantially the same thickness on each side of the axis of rotation of said member, one of said portions extending radially from said pivot to act as a fluke, the other portion being extended in an axial direction relative to said pivot to act as a stock and drag members attached to the outer ends of said portion acting as a stock, said drag'members being spaced from said shank and shaped to materially increase the cross-sectional area of said ends at a right angle to the plane of said member.

JOHN K; NORI'HROP.

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