FR2556435A1 - CHAIN, IN PARTICULAR FOR ANCHORING ON THE GROUND - Google Patents

Abstract

THE INVENTION CONCERNS AN ORIENTED CHAIN, USABLE IN PARTICULAR IN A LOAD ANCHORING DEVICE ON THE GROUND OR ON THE FLOOR. THE CHAIN INCLUDES A PLURALITY OF LINKS OF ELONGATED PROFILE, ASYMMETRICAL AND NON-REVERSIBLE, EACH LINK INCLUDING A FIRST AND A SECOND PART WHICH ARE PLACED ON OPPOSITE SIDES OF A THEORETICAL MEDIATOR PLANE PERPENDICULAR TO THE MAIL-LONGITUDINAL DIRECTION, NON-REVERSIBLE. -REVERSIBILITY BEING CONFERRED TO THE LINKS BY FORMING ON THEM, ON THE SAME SIDE OF THE MEDIATOR PLANE, OF THE PROHESES 57 OR THE CROSS BARS, WHICH PREVENTS AN INCORRECT INTRODUCTION OF THE CHAIN IN REVERSE DIRECTION INTO THE ANCHORING DEVICE 10. APPLICATION ATTACHING AIRCRAFT OR HELICOPTERS TO AIRCRAFT CARRIERS.

Description

The present invention relates to a chain,

especially for anchoring on the ground.

  U.S. Patent 2,903,767 describes a tension and chain anchor device which has been widely used in the military field for

  anchoring chains on the ground in various

  including the setting of loads such as planes and helicopters on the deck of an aircraft carrier. The device includes a pivotally mounted muffle defining an inlet path for receiving a tensioned portion of the chain attached to the load. The muffle also defines an exit path from which emerges the free or relaxed end

chain.

  The attachment device is designed to re-

  with a heavy load exerted by a

  due that is installed correctly, but it is less robust if the chain is inadvertently inverted during installation. Thus, the structural strength of the entire anchoring system is compromised if the tension chain is improperly engaged in the

  way out of the muffle and if the free end

  stretched out by the entrance way. Although the provisions

  Anchoring devices of this type shall be provided with a warning sign to prevent installation of the chain in the opposite direction, incorrect insertion in the opposite direction

  reverse can be and is sometimes done.

  An important object of this invention is to create a "directed" chain of a new type, which is

  fully compatible with the large number of

  already in use, which do not require

  site no modification of existing devices and

  which prevents an introduction in the opposite direction, by inad-

  vertance, of the chain in the device.

  This invention relates to what may be called a "unidirectional" chain having links

  placed between the extreme links which are not

  and in which the links are formed by two parts that are not symmetrical to each other. These features are easily highlighted by considering a classic chain link

  having a race track shape or an oval shape.

  Non-reversibility is most easily established in such a link by ensuring that the lateral internal spacing of the branches of the link is less than twice the diameter of the section.

  right of the metallic element, typically round,

  the link. Links with this geometry do not

  can not be reversed because there is an in-

  insufficient time for the extreme games

  adjacent links swap positions. A non

  reversibility can also be established by other link profiles (for example a wasp-sized link), by means of a lateral bar extending transversely to the links, or by means of a

  projection that narrows the opening of the link.

  In a chain with non-reversible links, it is possible to assign a directional direction to the links and the chain. One end of the chain

  can be defined as the load end and the ex-

  opposite end as the end relaxed when the chain is hooked on an anchor between its ends. Typically, the load end is identified by the addition of a hook or other fastener. A first end of each non-reversible link is always directed

  towards the charging end, and a second part ex-

  the very end of the link is always directed towards the relaxed end. The non-reversible links are further shaped to be asymmetric or anisotropic to a degree that the end portions of a link have different shapes by observing them from a generally central portion of the link. For example, the second extreme parts (directed to

  the relaxed end of the chain) can be laterally

  extended (or widened in a direction normal to the main plane of the link) in relation to the

  corresponding of the first extreme part. By going

  laughing, one or more protrusions can be formed

  on the second extreme parts of the links.

  When used in combination with the chain anchor device described above, the

  non-reversible asymmetric links can be

  allowed by the device only in a correct orientation where the voltage load end is

  input channel of the device while the end

  due from the chain comes out of the way out. An installation

  Inverse and incorrect translation of the chain is prevented because the second ends of the links can not be engaged in the exit path of the device and the locking of the device can not be completed completely. No modification of the device itself is necessary to obtain

  this important safety feature.

  Other features and advantages of the

  will be highlighted, in the following

  description, given by way of non-limiting example, with reference to the appended drawings in which:

  FIG. 1 is a perspective view of a

  Positive tension and chain anchor; FIG. 2 is a perspective view of a chain muffle used in the anchoring device; FIG. 3 is a reduced scale side elevational view of the device; FIG. 4 is an enlarged view of

  the upper end of FIG. 3, showing the dis-

  positive in part in a broken view with a conventional anchor chain installed incorrectly; FIG. 5 is a view similar to FIG. 4 but showing the chain according to the invention which is correctly installed in the device; FIG. 6 is a view similar to FIG. But showing how the warp of this invention prevents an inadvertently reversed installation; FIG. 7 is an elevational view partly in section, of an anchor chain according to the invention; FIG. 8 is an elevational view, partly in section, of a chain having another style of links; FIG. 9 is an elevational view, partly in section, of a third style of link; FIG. 10 is an elevational view, partly

  in section, a fourth style of link.

  The string tensioning and securing device briefly described above is fully described in U.S. Patent 2,903,767, which is hereby incorporated by reference. However, we will give in the following, to facilitate the understanding of the invention,

  a short description of the main structure of

these measures.

  With reference to Figs. 1 and 2, a tensioning device and chain anchor 10, according to what is indicated in the aforementioned patent, comprises a frame formed by side flanges 11 and 12 spaced apart from each other. A chain muffle 13 (shown in more detail in Fig. 2) is supported

  pivoting between the side flanges by means of

  14. The muffle 13 has a chain inlet channel defined by a slot 15 which is open at its front end and which extends through the muffle, giving the latter a somewhat U-shaped appearance by looking at him from the top. An upper surface 17 of the muffle is provided with a concave profile around the top of the slot so as to provide clearance for the first link of the chain above the muffle, and

  opposite branches 18 of the muffle define the

side kings of the slot.

  A chain exit path is defined in the muffle by a pocket 20 which extends laterally to each leg 18 on opposite sides of the slot 15. The upper front portions of the legs form lips 21 which are overhanging relative to each other. at the front of the pocket. As indicated by the chain links represented by phantom lines in FIG. 5, the pocket is dimensioned to receive a portion of a roughly horizontal link having a principal plane oriented in

  the assembly parallel to the axis of the journals 14.

  The slot 15 is shaped so as to receive a

  part of a taut vertical link having a principal plan

  overall perpendicular to the axis of the

  greaves. A shoulder 26 provided at the lower front end of each branch 18 constitutes a stop opposing the rotation of the muffle and another shoulder 27 provided on the upper rear part of the muffle constitutes a stop opposing a rotation in the direction opposite. A bar 28 (Fig. 1, 3, and 4-6) is fixed between the side frame flanges 11 and 12 so as to abut against the shoulder 27 to limit

  the rotation of the mittle in one direction when the

  The bar 28 is also unlocked, the bar 28 also limiting the rotation in the opposite direction when the device is either locked or unlocked, by coming into contact with each other.

  with the rear surfaces of the branches 18.

  A primary lock for the chain block consists of two cam plates 30 spaced from each other and pivotably mounted on an axle 31 fixed on and extending between the side flanges 11 and 12. A handful primary latch 32 has two branches 33 extending upwards and having elongate slots (not shown) receiving the axis 31, thereby rotatably supporting the handle on the axis and also allowing a limited linear movement of the handle relative to the axis. An elongated slot 35 formed in the lower end

  each plate 30 receives the flat surface of the

  32 to couple the handle with the plates 30 and allow the linear movement of the handle. A ratchet or secondary latch 38 is rotatably mounted and positioned. in the center on axis 31

  between the branches 33 of the primary lock handle.

  The latch 38 has an enlarged head 39 forming a thumb actuating surface and also providing an anti-rotation stop when the head contacts the front surfaces of the legs 33. A spring (not shown) urges the head against said front surfaces. branches and it also pushes the primary lock handle linearly downward away from the axis 31. In this extended position, the lower end of the primary lock handle is held in two snap-shaped depressions 41 formed in the side flanges 11 and 12 when the primary lock is closed,

as shown in Figs. 1 and 3.

  An elongate, centrally slotted tail 43 extends between and downwardly from the side flanges 11 and 12 to a lower end 44 adapted to be connected to a hook 44a (FIG. bearing surface such as the deck of an aircraft carrier or the floor of a cargo plane. Teeth 45 provided on opposite edges of the shank are placed in correspondence to internal teeth (not shown) placed on the inner side of an adjusting wheel 46. A rotation of the steering wheel allows

  a movement of the tail with respect to the chassis of the disc

  positive in order to adjust the overall length of the

  to remove a slack in the chain of

  attached cage. In use, a conventional anchor chain 48 is engaged in the muffle 13 of the device as shown in FIG. 3. The stretched portion of the chain extends upwardly from the device inlet channel (slot 15) to a load such as an aircraft to be fixed to the deck of an aircraft carrier. The relaxed end of the chain goes out through the device exit path

  (pocket 20). The tension load of the chain is trans-

  placed by the substantially vertical link in the slot 15 to the substantially horizontal link which is trapped in the pocket 20 of the relatively massive chain muffle. A rotation of the locked muffle is prevented by the upper ends of the cam plates 30 which abut against the shoulders 26 and by the bar 28 which abuts against the

  rear surfaces of the branches 18 of the muffle.

  The voltage load is therefore trans-

  placing the trapped link and generally horizontal chain muffle, through the trunnions 14 to the side flanges 11 and 12, and from the side flanges, through the tail 43,

  at the carrying deck or other supporting surface.

  The rear end of the horizontal link is trapped by a blind pocket 20 and this link can not

  escape from the mittens backwards. A relative force

  light weight which may tend to push the horizontal link forward out of the pocket

  counterbalanced by the fact that the end of the latch se-

  Condier 38 abuts against the lower end of the vertical link (Fig. 5) and thus limits the forward movement of the horizontal link. The heavy load of

  tension of the anchor chain pushes the horizontal link

  zontal in a direction of approximation (instead of a direction of removal) of the rear wall of the pocket 20 and against this, and the secondary lock can be of a lightweight construction-since it does not normally constitute anything more than an organ of

  retention (and rapid release) of a chain of

  slightly loaded or relaxed.

  As has been described in detail in U.S. Patent 2,903,767, the normal locked position of the device (with the latch handle 32 engaged in and held by the latching portions 41) prevents the chain muffle from rotating. When the chain is to be released, the latch handle is moved upwardly away from the latching portions 41 and is then turned outwardly away from the ends of the latches.

  plates 30 of the shoulders 26 of the chain muffle.

  This allows the chain block to turn into

  a position where the chain slips out of the device.

  With a relaxed or lightly loaded chain, uncoupling can also be achieved simply by rotating the secondary latch 38 until the engaged links can slip out.

off the chain mittens.

  Anchoring devices of the kind

  20 are of rugged construction and have proven extremely reliable in securing heavy military aircraft in extreme conditions, as in the case of

  aircraft carrier by a strong sea, or in a plane-

  cargo in air with severe turbulence. However, this reliability depends on

  correct installation of the anchor chain, the former

  tense or chain load from the entrance to the muffle while the end

  relaxed part of the way out. Despite the

  In the case of personnel and warning signs placed on the device itself, an incorrect reverse installation sometimes occurs, with the result that the structural integrity of the device is compromised. A properly installed chain (Fig. 3 and 5) transmits the chain load to journals 14 without generating a large torque that tends to rotate the muffle 13 clockwise (looking at Fig. 3 and Figs. 4 to 6) in opposition to the retaining effect of the cam plates 30 which rest against the shoulders 26. A small clockwise torque is intentionally generated to cause the muffle to rotate. automatically to an open position (in which the cat is released without further manipulation) when the lock handle 32 is open. This slight torque is however easily absorbed by the plates 30 when the lock handle is closed and the unusual side loads acting on the relaxed end of the chain are

  -absorbed by the end of the secondary latch 38.

  Even without the secondary lock, a tight chain

  is kept captive in the muffle because of the

tilting of the pocket 20 (Fig. 5).

  A classical chain 48 incorrectly

  tallée is shown in FIG. 4, the relaxed end 48a exiting through the slot 15 of the muffle 13 and the stretched end 48b from the pocket 20 of the muffle. The line of action of the tension force is separated from the axis of the journals 14 by a large lever arm and this results in the application of a high torque (arrow 49 in Fig. 4) to the chain muffle . When the anchor chain is very heavily loaded, this torque or moment can cause deformation or breakage of the muffle, plates 30 or secondary lock 38, causing a separation of the

chain and anchor.

  An attempt was made to modify the structure of the

  positive anchoring to solve this problem but no acceptable solution was found. However, it was realized that the problem could be alleviated with a modified chain and without the need for a

  anchoring already in service. The solution is structural

  effective and is economically attractive because of the relatively untouched nature and little

complicated anchor chains.

  With reference to FIG. 7, An anchor chain

  50 modified in accordance with the invention comprises a

  seems to be linked together. An ex-

  treme 51a is associated with a conventional hook 52 which is chosen to establish the connection with a coupling member provided on the aircraft or on another load to be fixed. The opposite end of the anchor chain is

  simply ends with a final link 51 and the posi-

  hook 52 therefore defines the end

load or tension of the chain.

  The links 51 generally have a race track shape or a classic oval shape, with two exceptions. Firstly, the cross-section diameter (dimension 53 in FIG. 7) of each link is chosen to be greater than half the internal spacing (dimension 54 in FIG. 6) of the branches 55 of the link which are joined by curved ends 56. In the second place, protrusions 57 are formed on the branches of the link in the direction of the end of the latter which is opposite the end.

stretched out of the chain.

  As described above, the relationship between the cross-sectional diameter of a link and the internal spacing of a link gives the links the important property of non-reversibility. This property can be established by other means (for example, by incorporating an internal projection or a central bar 59, shown in phantom in Fig. 7), but the above dimensional relationship simple and inexpensive way to reach the goal. The projections 57 are dimensioned so that the link end bearing the protrusions can not be introduced into the pocket 20 of the chain muffle. As shown in FIG. 7, the projections are formed by annular ribs of solder metal on the links, the outer diameter of the ribs being greater than the play gap created by the pocket 20 in the chain muffle. However, the projections do not need to surround the entire link and a correct variant consists in forming only a "boss" or outer projection 62 extending laterally on each branch of a link 63, as

  shown in FIG. 8. The protrusions 62 extending laterally

  the branches of the link sufficiently to make contact with the side walls of the pocket 20 and thereby to prevent insertion of the

link in the opposite direction.

  The projection on the chain link can by

  therefore be formed in such a way as to extend

  outward in the direction of the plane of the flat link, or it may also be formed so as to extend away from the link in a

  direction perpendicular to the plane of the latter.

  The anchor chain 64 shown in FIG. 9 com

  carries links 65 provided with projections 66 oriented in the last mentioned manner, but it must be ensured that the projections are limited in size in order to avoid an obstruction at the entrance of the relaxed end of the link in the slot 15 defining the way of entry

in the chain muffle.

  In either case, a reverse insertion is prevented by contacting the protrusions with the walls delimiting the pocket 20. Only one protrusion can be used but two protrusions are preferred for

  allow immediate visual identification of the former

  link tremity directed towards the relaxed end

chain.

  Another form of asynchronous link design

  metrics 68 in an anchor chain 69 was

  felt in FIG. 10. Instead of involving an enlargement of the section of the link branches as in the links 51, 63 and 65, the links 68 have a constant cross-sectional shape but asymmetry is established by widening the lateral internal spacing of the branches. 70 of the link placed at the relaxed end 71 of the chain compared to the corresponding dimension of the link placed at the end of load

72 of the chain.

  This gives the link roughly the shape of a truncated triangle with rounded vertices, as shown in FIG. 10. The end 71 is sized to be too large to engage the pocket 20 but the small end 72 and adjacent portions of the links of the link may be fully engaged in the pocket. Non-reversibility of the link is maintained by maintaining the lateral internal spacing of the branches of the link at the relaxed end of the link to a value less than twice the size of the link.

cross section of the link.

  Figure 5 shows an anchor chain 50

  (of the style described above) that has been correctly

  mounted in a muffle 13 of an anchoring device 10.

  A vertical link 51b of the taut end of the chain is properly engaged in the slot 15 which

  is wide enough to accommodate projections 57.

  An approximately horizontal link 51c is engaged in the pocket 20 of the mitt and projections 57 of this link do not interfere with a complete introduction of the link into the pocket. Fig. 6 shows an attempt to install

  of the chain 50 in a reverse and incor-

  in the anchoring device. Projections 57 of the link 51c interfere with the introduction of this link into the pocket of the muffle, preventing the establishment of the link and the contacting of the secondary lock

  38 with the vertical link 51b in the slot 15.

  The operator is therefore immediately warned of the incorrect orientation of the chain and this is reversed for installation in the correct direction. In the embodiments described above, the blockage effect which prevents a reverse insertion of the anchor chain is manifested between the exit path of the device which is defined by the pocket 20 and a widening of the loose chain end of the links. However, it is possible to establish the obstruction between the input channel of the device and projections placed at the load end of each link. However, this solution requires a different geometry of the input channels

  and exit to ensure that a correct link

  mentally oriented can be fully engaged in the output path, and the configurations already described

  are therefore preferred because no

  existing anchoring devices is necessary.

  The end of the stretched part of the chain is unambiguously defined for the user by the presence of a hook for the connection with the load to be fixed. The opposite end of the chain may be permanently attached to the anchor if desired, or it may simply be a free and relaxed end. In the

  the last case, the chain must be of sufficient length

  to ensure that the extreme link in the end

  tense (which is reversible because it is loaded only by an adjacent link) is not connected

to the anchoring device.

  We can even eliminate this possible ambiguity in different ways. First, the link of the relaxed end of the chain may include a central bar or other means as described above to prevent reversal. Secondly, the final link, although reversible, may be provided with a circular profile or any other enlarged profile which

  can not be engaged, regardless of the direction

in the pocket of the mittens.

  An improved anchor chain has been described above which eliminates inadvertent and unsafe reverse installation of the chain in a widely used type of tension and chain anchor device. Any

  modification of the device is necessary and it is sufficient

  made a simple and relatively inexpensive amendment to the shape of the links in the chain for

achieve this important goal.

Claims (12)

  An oriented chain, characterized in that it comprises:   a plurality of elongated, non-reversing links   sible and asymmetrical (51; 63; 65; 68);   - each link between the links of ex-   trenches of the chain being coupled to two adjacent links and having spaced-apart ends (56), and a pair of legs (55) joining said ends, each said link comprising a first and a second portion located on sides   opposite of a theoretical plane perpendicular to the length   the link and cutting the link in two, said first and second parts having outwardly facing surfaces of different shapes; the links (51; 63; 65; 68) being arranged   to be non-reversible so that the links are   extending between the end links (51a, 51b) are held in a predetermined orientation where the first portions extend toward a first chain end (48a), and the second portions extend toward a second end of   chain (48b) when the chain is in extension.   2. Chain according to claim 1, characterized in that the legs (55) of each link (51; 63; 68) are laterally spaced (54) from each other by less than twice the minimum dimension of section   right (diameter) (53) of the link (51; 63; 65; 68).   3. Chain according to claim 1, characterized in that said profile difference is established by a projection (57; 59, 62) placed on the second part. links (51; 63; 65; 68).   A chain according to claim 1, characterized in that said profile difference is established by a pair of projections (57; 59; 62) placed on the   second part of the links (51; 63; 65; 68).   Chain according to Claim 4, characterized   in that the projections are annular ribs (57).   Chain according to Claim 4, characterized   in that the projections (57; 59; 62) extend laterally   from the links (51; 63; 65; 68). Chain according to claim 4, characterized in that the projections (57; 59; 62) extend from   links (51; 63; 65; -68) in a direction   dicular to the main plane of the links.   8. Chain according to claim 1, characterized in that the material forming each link (51; 63; 65; 68) has a cross sectional diameter (53) greater than half the width (54) of the internal opening. side of the link (51), and that each second part of   link has a protrusion (57; 59; 62).   9. Chain used in combination with a chain anchoring device (10) having entry ways   (15) and the output (20) of the chain for receiving   Tensile and relaxed chain links, the outlet channel (20) being arranged to receive only a part of the link coming to rest therein, characterized in that it comprises: a plurality of links ( 51; 63; 65; 68)   coupled together, each link comprising a first   a first and second portion joined, the first portion comprising the link end oriented in the warp direction (51a), and the second portion being oriented in the direction of the relaxed end (51) of the warp; the first link part being profiled so that it can be inserted into a bearing condition in the exit path (20) of the chain anchoring device (10), and the second link part being profiled in such a way that it can not be inserted into the support condition in the exit path (20); and in that the chain can be engaged in the   device only if the loose links extend   tooth from the exit route, an incorrect installation in the opposite direction of the chain being prevented by the impossibility of the second parts of links   to be lodged in the exit lane (20).   10. Chain according to claim 9, characterized in that the links (51; 63; 65; 68) are profiled so as to be non-reversible with respect to the links. adjacent mated.   11. Chain according to Claim 10, characterized in that a non-reversibility is established by profiling   the links (51; 63; 65; 68) with central openings   insufficient to allow   adjacent links coupled to be swapped in position.   12. A chain according to claim 10, characterized in that each second link portion has at least one projection (57; 59; 62) which prevents this second   part of being received in the output path (20).