JPH0259119B2 - - Google Patents

Description

Claim 1. A tension dampener for wire rope or other relatively inelastic but flexible wire, comprising: a frame; a rotatable arm having a first axis of rotation; said arm being connected to said frame. a resilient torsion spring oriented about the first axis of rotation of the arm for the purpose of operation; parallel to the first axis of rotation of the arm and intersecting with the arm in a first position; a first sheave having a second axis of rotation and rotatably attached to the arm; a first pulley rotatably attached to the arm at a second location spaced apart from the first location; , a second sheave having a third axis of rotation parallel to the first axis of rotation of the arm; as the rope passes through the shock absorber, the rope guided by a pulley and a second pulley into a general S-shape, and as tension applied to the rope increases, the S-shape is gradually distorted to a relatively straight configuration such that the arm
A tension shock absorber, characterized in that it rotates around a rotation axis.

2. The device of claim 1, wherein the elastic torsion spring includes a cylindrical body within which torsional shear is distributed in the longitudinal direction of the torsion element to produce a longitudinal torsional shear action. The tension shock absorber is characterized in that the cylindrical body has a first end that rotates together with the arm and a second end that is fixed so as not to rotate with respect to the frame.

3. The device according to claim 2, further comprising a second frame and a second elastic torsion spring, the second elastic torsion spring having substantially the same operating characteristics as the first elastic torsion spring. one end of the second elastic torsion spring is configured to rotate together with the arm, the other end of the second elastic torsion spring is fixed so as not to rotate with respect to the second frame, and The second frame is the first frame.
A tension shock absorber spaced apart from the frame of the apparatus and separated by the arm.

4. The apparatus of claim 1, wherein the elastic torsion spring includes at least a pair of cylindrical elastic torsion elements, at least one of the torsion elements being hollow and arranged in a concentric mounting relationship with a second torsion element. the torsion element of the hollow cylindrical element, a first end of the hollow cylindrical element being fixedly secured to a selected one of the frames and the arms, and a second end of the hollow cylindrical element an end of which is fixedly fixed to a first end of said second cylindrical element, and a second end of said second cylindrical element is connected to said arm. Buffer device.

5. A tension damper according to claim 4, characterized in that the connection between the second end of the cylindrical element and the arm is a rigid connection.

6. The device according to claim 5, wherein the connection between the second end of the second cylindrical element and the arm is a flexible connection comprising at least one further elastic element. A tension shock absorber characterized by:

7. The apparatus of claim 6, wherein a second frame is provided for securing the arm to a second frame spaced from the first frame and separated from the first frame by an arm. 1. A tension shock absorbing device characterized by comprising: 2 mounting-related devices.

8. The device of claim 1, wherein the resilient torsion spring has a hub portion and a peripheral portion, the hub portion rotating relative to the peripheral portion, and wherein the resilient torsion spring has a an essentially uniform radial torsional shearing action is applied through the elastic material, one of the hub and the peripheral portion being connected to the arm, and the other of the hub and the peripheral portion being connected to the frame; A tension buffer device characterized by:

9. The device of claim 1, wherein the elastic torsion spring is reinforced by a plurality of rigid annular discs.

10. The device according to claim 1,
A tension shock absorber characterized in that the elastic torsion spring is reinforced by a plurality of rigid tubes.

TECHNICAL FIELD This invention relates generally to navigational equipment, and more particularly to the application of tensile forces to ropes or other resilient wires securing a ship to a mooring arrangement as the ship moves relative to the mooring arrangement. This invention relates to a tension buffer device that can be used to absorb sudden changes.

BACKGROUND OF THE INVENTION When a boat or other vessel is moored to a pier or other mooring facility by wire rope or other flexible but relatively inelastic line, the line is placed under tension while the vessel and its mooring facility are moored. It is customary to provide the wire with some type of device that holds it in such a way as to provide a predetermined amount of elastic stretch that allows relative movement between the wires.

U.S. Pat. No. 4,022,450, entitled "Line Tensioning Device," is representative of such a prior art device, in which the wire is stretched when a predetermined amount of tensile force is applied to it, and the line is stretched further. A pair of tension springs is used to hold the Z-shaped elastic bend in line.

"Cable Batsuhua"
No. 546,788 and No. 869,130 entitled "Yielding Boat Cleat" and "Yielding Boat Cleat," when excessive tension or strain is applied to a mooring net, cable or rope, one or more coils A prior art mechanical device is disclosed in which a spring is compressed.

"Improvements in Windlasses" and "Surge Release Devices" respectively.
U.S. Patent No. 1 entitled “Surge-Relievers”
No. 143993 and No. 107917 disclose other devices in which the shock of the cable caused by the movement of the ship is absorbed by a plurality of rubber springs.

The aforementioned strain absorbing devices according to the prior art use spring elements that are compressed or stretched in a linear direction;
There is therefore an approximately linear relationship between the stress applied to the rope and the resulting increase in the effective length of the rope.

“Oil Storage Vessel, Mooring Equipment and Oil Sending Equipment for Offshore Oil Refining”
Apparatus And Oil Delivery for The Off−
U.S. Pat. No. 4,273,066, entitled ``Shore Production of Oil'', discloses a mooring line, which may be a floating rope or a weight chain, depending on the particular application;
We have proposed various devices for mooring ships at sea, including deep-sea diving mooring devices that include both oil supply hoses with flexible lengths. The patent describes in columns 5 and 8 a manually or automatically controlled tension release (automatic) mooring winch and a mechanical shock absorber (buffer roller). It is described in column 5 of the said patent as being designed and regulated to absorb a portion of the periodic shock loads applied to the mooring line. “Dampa (The
Damper). The damper is described as including a concave roller with an abutted end over which the mooring line passes;
The roller is held at a particular height above the wire rope winch and behind the winch by two arms pivoting about their axes, the latter being supported by spring or hydraulically controlled rams. This keeps it in place. The above-mentioned patent also discloses a mooring method for creating a resilient connection between a floating storage tanker and a service tanker by placing the propeller of a service tanker in a reverse position to generate a predetermined tension in a mooring line, thereby creating a resilient connection between a floating storage tanker and a service tanker. It describes the use of right-of-way lines and the relative movement between both ships.
Oil hoses are installed to accommodate up to 150 feet (approximately 45 meters) (12 simultaneous rails).

Mechanical tensioning devices have also been used to maintain a somewhat constant tension in endless drive belts, such as when used to drive various auxiliary devices associated with modern prime movers. Such a belt tensioning device compensates for belt length changes over its service life, while eliminating slip between the belt and the various pulleys moving around it, and at the same time without applying excessive tension to the belt. Used to ensure proper tension on the belt.

"Mechanical Belt Tensioner Construction" respectively
and “Tensioning Apparatus”
U.S. Pat. No. 4,285,676 and its Reissue Patent No. 330,842 disclose typical prior art drive belt tensioning devices in which tensioning of a belt as it extends between adjacent stationary pulleys is disclosed. A torsion spring is provided at one end of the lever arm for pivoting the idler pulley at the other end of the lever arm in a direction generally perpendicular to the longitudinal direction. The torsion spring (for example, patent No. 4285676
(as shown in Reissue No. 30,842 of said patent) or alternatively (as shown in Reissue No. 30,842 of said patent) as a result of torsional shear forces being applied to the elastic material to generate the necessary rotational force. A hollow cylinder made of elastic material may also be used.

``Chain Dive'' with an idle foil tensioning device compressed by elongated pads.
with Idler wheel Tensioning Means Biased
by Elongated Pads)”
No. 3,817,112 relates in particular to chain drives for weaving looms, which may stop and restart abruptly, thereby subjecting the chain to significant strain. As the tensioning device rotates, the cross-sections of the rubber pads become distorted, creating a torsional effect.

It is recognized that the shock absorbers that have been used in continuous belt chains and other similar drive systems are never required to cope with the particularly large forces and constant bangs associated with many nautical applications. Therefore, the reaction force caused by applying an unbalanced torque (rather than an balanced torque couple) is
The reliability of the shock absorber when used for its intended purpose is unlikely to be significantly affected.

“Tilting mechanisms especially for chairs
No. 2,087,253 entitled "Mechanism Especially For Chairs", the tubular members are highly compressed and surrounded by concentric tubular members, so that said tubular members are effectively bonded to the surfaces of said tubular members. illustrates the use of a cylindrical body made of rubber, in which relative rotational movement between the rubber bodies torsionally distorts the rubber body. An adjustment mechanism is provided to vary the torsional strain applied to the rubber and thus the force required to tilt the wall of the chair supported by the elastic rubber device. A construction configuration such as that described above allows for limited rotational movement between adjacent construction elements and at the same time allows for a variety of applications in which cylindrical rubber bushings are used to spring the mechanism into its normal position. Considered typical. The bush mentioned above has a cylindrical shape, but hereafter it is called "longitudinal torsional shear".
It should be noted that the radiating torsional shear is not used and that the radiating torsional shear is not evenly distributed but concentrated in the hub section.

DISCLOSURE OF THE INVENTION A novel rope tension dampener is adapted to be installed at an intermediate point in the length of a wire rope or other similar elastic line. For example, a tensioning device is installed on the deck of a ship between a winch that controls the effective length of the rope and a line guide that guides the rope, and is used as the rope is wound around the winch and unwound. You can avoid getting tangled. Alternatively, the device preferably includes a tether;
It may be installed near the fixed end of the rope between the cleat to which the rope is attached.

The actual device includes a pair of coplanar pulleys each mounted at opposite ends of a rotatable arm. The two sheaves are oriented so that their axis of rotation is parallel to the axis of rotation of the arm, so that the rope enters the shock absorber tangentially to a point on the circumference of the first sheave. the longitudinal direction of the arm as the rope moves in and out of the shock absorber before applying any tension to the rope, causing the rope to exit the shock absorber in a direction tangential to a second point on the circumference of the two pulleys. By making the axis somewhat perpendicular to the direction of the rope, the rope in the shock absorber is guided by the two pulleys and has an overall S-shape, so that the tension of the rope is controlled by the torque force relative to the arm. As the force is applied, it gradually assumes a relatively straight shape, thus causing the arm to rotate more and more parallel to the direction of the rope outside the shock absorber. One or more resilient torsion springs connect the rotatable inner arm to the outer fixed frame, and shear forces within the resilient material create a torque couple on the rotating inner arm, thereby assembling the arm and pulley. A variable damping force is applied to the rope as it rotates from its zero load position.

According to a preferred embodiment of the invention, the elastic torsion spring is in the form of a pair of hollow cylinders, one placed concentrically inside the other, the axes of which coincide with the axis of rotation of the arm. an axis, the first end of the outer cylinder being fixed to the first end of the inner cylinder such that one of the respective second ends is attached to the arm; When the end is attached to the outer frame, the torque generated by the inner elastic cylinder and the torque generated by the outer elastic cylinder are combined. Since each of the two mounted cylinders only needs to accommodate a portion of the rotation of the arm relative to the outer frame, the corresponding length of each cylinder is for a given maximum shear angle in the elastic material. shorter, thereby allowing a more compact structure to be constructed for a given operating parameter.

Preferably, a pair of elastic torsion members having concentric rotation axes are provided, one on each side of the rotatable arm.

According to other embodiments of the invention, the elastic member is an elongated cylinder attached at one end to the rotatable member and at the other end to a stationary member, or a hub portion to one of said members and an edge to the other of said member. It can be any shape of a disk attached to.

As a result of said structural shape, as the arm rotates and extends the S-bend with increasing rope tension, the leverage associated with the torque couple exerted on the arm by the rope tension correspondingly decreases. Become. Since the elastic material generates a counter-torque roughly proportional to the angular movement of the arm, the shock absorber always maintains at least a small bend in the cable, thus preventing any further instantaneous increase in tension applied to the cable. Can be absorbed. As the rope enters and exits the shock absorber, by suitably initializing the orientation of the rotatable arm with zero torsion load relative to the direction of the rope, the operating characteristics of the shock absorber, in particular the effective length of the rope, are adjusted to a given tension. The rate of change for the increment can be changed.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a rope tension buffer according to the present invention used on the deck of a ship to absorb sudden changes in the tension of ropes used to attach ships to mooring buoys; FIG. 3 is a partially sectional side view of the damper shown in FIG. 2; FIGS. 4a and 4b are twisted into a cylindrical body; FIG. FIG. 5 is a perspective view of a pair of cylindrical bodies made of elastic material showing the geometric relationship between shear and torsion before and after shear force is applied; FIG. Therefore, the second type of rope tension shock absorber provides a more compact device.
FIG. 6 is a partially sectional side view of the embodiment shown in FIG. 5; FIG. 7 is a perspective view of a third embodiment of the rope tension shock absorber; FIG. Partially cross-sectional side view of the embodiment shown in FIG. 7;
From Figures to Figure 14, the angles between the arm and the outward direction of the rope are -30 degrees, 0 degrees, and 15 degrees, respectively.
FIG. 15 is a geometric drawing schematically showing a rope tension damper according to the invention when the initial direction of zero load of the arm on the rope is 45 degrees, 45 degrees, 90 degrees and 120 degrees, respectively. degree, 15
2 is a set of graphs illustrating the tension applied to a rope as a function of displacement for degrees, 0 degrees and minus 30 degrees.

CURRENTLY PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION Reference is now made to the drawings, and in particular to FIG. 1, which is a schematic illustration of a device according to the invention used to absorb changes in tension in mooring ropes. The ship 10 is attached to a mooring buoy 20 by a mooring rope 30. Typically, the mooring rope 30 is a stranded steel cable having an overall diameter of approximately 5 cm and capable of withstanding significant tensile forces, but may be any other suitable type of rope or chain. . cable 3
Typically, the mooring buoy 20 has more than enough strength to attach a relatively large vessel (for example, a 100 ton oil tanker). However, on the high seas, wave action causes the ship 10 to undulate, thereby causing relative movement of the ship 10 and its mooring equipment. Therefore, as the ship 10 moves towards its mooring facility, the mooring rope 30 tends to slacken. Conversely, the ship 10 is the mooring facility 30.
As the inertia of the ship 10 is transferred through the now taut rope 30 to the mooring facility 20, the slack in the cable 30 increases as it moves away from the cable 30, unless suitable devices are provided to prevent excessive tension. 30 must withstand sudden and potentially large force impacts. To a certain extent,
Although the effect of increased tension on the rope 30 can be counteracted by the prior art spring-loaded shock absorber described above, it is also possible to avoid increasing the tension in the cable 30 before the cable 30 is automatically unwound. The winch 40 may be designed and operated to provide very limited resistance to. Although such measures are effective within certain limited operating requirements, the tension applied to the rope before the tensile force increases to the point where it equals or exceeds the tensile strength of the rope or its connections. It should be recognized that there is still a need to provide suitable equipment to reliably buffer and absorb.

As shown, the mooring equipment is a buoy 20,
This is also affected by waves. However, buoy 2
0 is typically anchored to the sea bed by means of an anchor and/or pipe (not shown) arrangement which is kept under tension by its buoyancy. Although it is possible to minimize the wave action on the buoy 20 because most of the volume of the buoy 20 is sunk to an appropriate depth where it is not affected by the action of violent waves, the buoy 20 also resists the swells of the ship 10. A certain kind of motion is added which is out of phase with the
It is observed that the relative motion between 0 and 0 is added.

A first end of the cable 30 is wrapped around a winch 40 on the deck of the ship 10, and the other end of the cable 30 is attached to the buoy 20 by a suitable attachment 50.
The winch 40 thus adjustably secures the cable 30 to the ship 10. The new rope tensioning device 60 includes the winch 40 and the tensioning device 6.
In order to control the direction of the exit portion 80 of the cable 30 with respect to 0, the cable 30 is mounted on the ship 10 at an intermediate position between the cable conductor 70 provided at the edge of the ship. The portion 90 of the cable 30 that enters the line system 60 is typically such that the cable 30 extends directly from the winch 40 to the line system 60 and that both the winch 40 and the line system 60 are mounted together on the deck of the ship 10. Due to the fact that the winch 40 and the tensioning device 60 are both properly oriented. Further, the entry portion 90 and the exit portion 80 of the cable 30 are oriented generally parallel to each other, but spaced apart such that as tension is applied to the cable 30, a torque couple is applied to the tensioning device 60. has been done.
The magnitude of the torque couple is determined not only by the tension of the rope 30 but also by the vertical distance of the input section 90 relative to the output section 80 of the cable.

In this regard, by anchoring the oil tanker against a buoy placed at the upper end of the riser conduit from the subsea well, the vessel can be suspended while elastic oil piping (not shown) pumps oil from the well to the tanker. Although particularly suitable for use in positioning against mooring buoys, the tensioning device 60 can also be attached to piers or to piles penetrated into the seabed (e.g. in shallow water areas along the Dalung Shelf). A service tanker may be attached to a fixed mooring facility such as a fixed platform, or a floating storage vessel moored near a subsea well while a tugboat is being loaded onto a barge, or a service tanker is loading oil from a storage vessel. (as when connecting the first ship to the second)
It should be noted that it can also be used advantageously when connecting to other ships.

Reference is made to FIGS. 2 and 3, which are perspective and side views, respectively, of the shock absorber shown in FIG. The rope 30 is routed from the generally horizontal portion extending between the winch 40 and the tensioner 60 to the upper sheave 102.
is guided by the upper sheave 102 over the forward portion 104 of the rope to the rear portion 106 of the lower sheave 108 to the lower horizontal portion of the rope 30 as it extends from the tensioning device 60 towards the conductor 70 (FIG. 1). be guided by.

An upper sheave 102 and a lower sheave 108 are rotatably attached to the upper and lower ends, respectively, of a rotatable arm assembly 110. As shown, the longitudinal direction of the arm assembly 110 is generally vertical when at rest (i.e., when there is no tension on the cable) and is therefore horizontal in each of the entry and exit portions 90, 80 of the cable 30. It is generally perpendicular to the surface.

In the embodiment shown in FIGS. 2 and 3, the arm assembly 110 is interconnected by a pair of spacing plates, an upper sheave pin 116 at each upper end and a lower sheave pin 118 at each lower end. It includes a left side plate 112 and a right side plate 114. The upper sheave 102 is connected to the upper pin 116.
The lower sheave 108 includes a similar hub bushing 120 that allows the sheave to rotate in a coaxial relationship about the lower pin 118, while the lower sheave 108 includes a similar hub bushing 1 that allows the sheave to be similarly rotatably mounted about the lower pin 118.
Contains 22. Two pulley pins 116, 118 are respectively fixed to each one of the two side plates 114 making up the arm assembly 110, and their free ends engage bushings provided as part of the opposing plate 112. Sliding in and out. With this method,
Some variation in the spacing between left plate 112 and right plate 114 may be tolerated.

The left arm plate 112 is connected to the left outer frame member 124 by the left elastic torsion spring 126.
It is connected to the. Similarly, the elastic torsion spring 1 on the right side
28 also connects the right side plate 114 to the right side frame member 130. With particular reference to FIG. 3, the left torsion spring 126 and the right torsion spring 12
8 are substantially identical to each other, and are each cylindrical, concentric around a common axis 132 that intersects the arm-side solid 110 at about 90 degrees (1/2π radian).

Referring to the left torsion spring 126 shown in cross-section in FIG. 3, the torsion spring assembly includes a relatively thick outer end plate 134, an intermediate portion 136 that is slightly thinner than the end plate 134, and an inner end plate 138. The intermediate spring portion 136 is molded from a suitable resilient member, such as neoprene or other rubber-like material, to withstand sunlight, salt water, and other related adverse environmental conditions encountered in a nautical environment. The intermediate section 136 also includes a plurality of rigid reinforcing plates 140, each of which is thin, relatively flat, and generally perpendicular to the axis 132 about which the arm assembly 110 rotates. be. The elastic member portions 142 of the elastic springs 126, 128 are bonded to the reinforcing disk 140 and the two end plates 134, 138;
Therefore, the inner end plate 138
, and when the outer end plate 134 is stationary, a torsional shearing action is applied to the elastic member 142 which causes the outer end plate 1
A torque couple is generated about axis 132 by an amount generally proportional to the amount of rotation of inner end plate 138 relative to axis 34 .

The function of the reinforcing plate 140 is that the axial center 13 of the cylindrical body 136
2, one end of the torsion spring can be wound up and unwound relative to the other end. This imparts anisotropy to the elastic spring without reducing the spring performance, and particularly strengthens the elastic material so that there is no undesirable deflection. (See also the explanation for Figure 4 below). This function is accomplished by orienting the reinforcing disk 140 in a predetermined shear direction. The reinforcing disk 140 also has the effect of minimizing the tendency of the elastic material to change length or diameter in response to simple external compressive and tensile forces. When a torque couple is applied to the reinforced elastic assembly 136 that creates a shear force in a direction perpendicular to the axis 132,
It is observed that the individual reinforcing plates are not subjected to any significant action.

In the embodiment shown in FIGS. 2 and 3, each outer end plate 134 is secured in position to a corresponding outer frame member 124, 130 by a plurality of fittings 144. Fittings 144 engage corresponding plurality of holes 146 in outer end plate 134 . Since the fittings 144 and their respective holes 146 are spaced at regular intervals (eg, 15 degrees) around the circumference, selecting a particular pin 144 to be inserted into a particular hole 146 allows the rope to be It will be appreciated that the initial angular orientation of the arm assembly 110 and the two pulleys 102, 108 can be adjusted relative to the direction of the rope as it enters 80 and exits 90 the tensioner 60. The minimum increment of such adjustment is determined by the angular spacing between adjacent fixtures 144. However, it will be clear to those skilled in the art that if fine adjustment is required, the aforementioned need can be met by providing an additional adjustment device to reduce the amount of each increment.

Left and right plates 1 forming arm assembly 110
12 and 114 are the inner end plates 1 of the left and right elastic torsion spring assemblies 126 and 128, respectively.
A plurality of bolts 148 are provided for securing to 38. In the illustrated embodiment, each side of the inner end plate 138 facing the arm assembly 110 is provided with a suitable groove into which each arm plate 112, 114 is partially embedded so that the end plate 138 and Each arm plate 112, 11
4 to prevent slipping and rotation. Thus, the individual bolts 148 securing the two end plates 138 to their respective arm plates 112, 114 are removed from the resilient springs 126, 128 to the arm assembly 110.
As a result of the torque being transmitted to and vice versa, it is not exposed to excessive lateral shear forces. In the illustrated embodiment, the resilient spring 126 is removed by simply loosening the arm fixing bolt 148 and sliding the arm 110 along the aforementioned groove in the inner end plate 138 to the desired position and retightening the bolt 148.
Height adjustment of arm assembly 110 relative to 128 and outer frames 124, 130 is also possible. In this regard, the arm assembly 110 is typically centered relative to the axis 132 of the cylindrical torsion element 136, and the winch 40 and conductor 70 (see FIG. 1) are connected to the entry and exit portions of the cable 30. 90, 80, so that only a pure torque couple is applied to the elastic springs 126, 128;
It is preferable to avoid applying excessive displacement force.

The torque developed by an elastic torsional element is expressed by the equation M=aG Ip/L, where a is the angular displacement of one end plate relative to the other in radians: G is kilograms per square meter (Kg/m ) is the shear modulus of the elastic material:
Ip is the polar moment of inertia in square meters (m4) and L is the axial length of the elastic material in meters (m). (For a solid cylinder, the polar moment of inertia Ip is equal to 1/4πR4, where R is the radius of the cylinder in meters).

One degree is 0.01745 radians, and the typical shear coefficient is 225 psi (approximately 1.6 × 10 ⁵ × Kg/m ² ), so a radius of 24 inches (approximately 0.61 meters) and a length of 46 inches (approximately 1.17 meters) , the pair of elastic cylinders shown in Figures 2 and 3 rotate approximately 520 meters per degree of rotation. It is calculated to produce a combined torque couple of kilograms.

Referring to FIG. 4, which shows the geometric relationship between shear and torsion, a square element 150 is formed on the outer periphery 152A of the elastic cylinder before any shear torsion is applied; The element is a cylinder 152
It can be seen that it is located at the outer and inner ends 154, 156 of the cylinder and parallel to the axis 158 of the cylinder relative to the straight line A-B connecting points A and B. However, one end 154 is rotated by an angle relative to the other end (cylindrical body 152B) so that the line connecting point A to point B is no longer a straight line parallel to axis 158, but rather a spiral 160. Then, square element 150 (sheared by angle α) becomes a distorted diamond 162 whose respective vertices are (1/2π-α) and (1/2π+α). For a typical elastic material, the maximum shear angle that can be applied to the material without losing its elasticity is limited to 45 degrees at the opening (1/4π radian). Typical values mentioned above (L=1.17 meters,
R=0.61 meters), the corresponding maximum rotation β of one end plate 134 relative to the other end plate 138 is approximately 1.9 radians (109 degrees).

Reference is now made to FIGS. 5 and 6, which illustrate another embodiment of the invention in which the mounting of elastic torsion elements results in a more compact device than that shown in FIG. 1.

It will be recalled from the discussion of FIG. 4 that even with conservative design, no part of the elastic material has a shear strain greater than 45 degrees. Thus, in the embodiment shown in FIGS. 2 and 3, the diameter of the cylindrical body is such that its length is sufficient to allow arm assembly 110 to be displaced 109 degrees in either direction from its rest position. should be approximately equal to. Furthermore, from the above formula for the torque developed by an elastic element as it is twisted about its axis, it can be seen that torque is a function of the polar moment of inertia about its axis. Therefore, the inside of the cylinder has relatively little influence on the overall torque. Considering the above requirements, it is possible to place two hollow elastic cylinders, one inside the other, with the first end of the outer cylinder fixed to the first end of the inner cylinder. If the torque generated by the inner elastic cylinder and the torque generated by the outer elastic cylinder are
The combination is such that only a small fraction of the 10 rotations need be allowed by each of the two mounted cylinders. The embodiments shown in FIGS. 5 and 6 utilize these ideas. In these drawings, the various reference numerals previously used for the embodiments shown in FIGS. 1 and 2 are retained, but a prime sign (') is used to distinguish similar elements in the two embodiments. is added. (The same is true for the embodiments shown in FIGS. 7 and 8 that use double prime signs ('').) Referring to FIGS. 5 and 6 in detail, FIG. 6 is a partially cross-sectional side view taken along line 6--6 of FIG. The height is determined by the vertical offset between the inlet section 90 and the outlet section 80 of the cable and is therefore generally the same as the corresponding vertical dimension of the previous embodiment, but in the longitudinal direction. It can be seen that it is much more compact in the direction of axis 132'.The function of the solid cylindrical elastic torsion element 126 (FIGS. 2 and 3) is that of the mounted pair of hollow torsion elements, i.e. This is accomplished by a hollow cylindrical element 170 and an outer hollow cylindrical element 172. An outer tubular jacket 174, which is rigidly attached to a central base 176, is similar to the left outer plate 124 of the previous embodiment. Correspond functionally.

The cross-sectional view of FIG. 6 shows that an inwardly projecting annular rim 178 is attached to the inner annular end plate 180 of the outer resilient element 172 by suitable mechanical fasteners 182. In the drawing, bolt 18
2, other attachment means, such as welding and/or rivets, may be used to provide the necessary relatively rigid connection between the outer skin 174 and the inner end plate 180. It is recognized that The outer end of the outer resilient element 172 terminates in an outer annular end plate 184 that is secured to the outer annular end plate 188 of the inner resilient element 170 by a plurality of bolts (or other suitable attachment devices). installed. The inner end of the inner resilient element 170 terminates in an inner end plate 138' that includes the left arm 11 of the rotatable arm assembly 110'.
2' is fixed. It can also be seen from the drawing that the radial thickness of the inner hollow cylinder 170 is slightly greater than the radial thickness of the outer hollow cylinder 172. As previously mentioned, the torque developed by an elastic element for a given torsion about its longitudinal axis is a linear function of the polar moment of inertia and actually increases as the fourth power of the radius. The outer torsion element 172 is equal to the inner torsion element 170 of the arm assembly 110.
Since it shares the torque and rotational motion of the inner elastic element, it should be about the same stiffness as the inner elastic element, but slightly thinner. Inner and outer elastic elements 170, 17
2 both employ the same reinforced, monolithic construction as the resilient element 136 shown in FIG. Preferably,
The rubber may be reinforced by plates of suitable reinforcing material, such as stainless steel, aluminum, or embedded in an elastic material during the molding process, perpendicular to the main axis of rotation 132' of the tensioner. Reinforced with Kevlar oriented to However, the individual reinforcing elements are not disc-shaped, but rather in the shape of an outer annulus 190 and an inner annulus 192, respectively. (In this regard, since the reinforcing function of the disk 140 is more required toward the periphery of the cylinder than toward the center, the embodiment shown in FIGS. 2 and 3 is It is recognized that the annular reinforcing element may be substituted and optionally modified for element 140).

Symmetrical to the corresponding structure described above for the left part of the right elastic spring and tensioning device of the second embodiment 60', which is inside the right annular jacket 190 and supported by the right base 192. It is recognized that To provide further rigidity, a top connecting link 194 is provided to connect the corresponding upper portions of the left tubular jacket 174 and the right tubular jacket 190.
It is advantageous to provide Such a connecting member 194 also provides a means for conveniently lifting the entire apparatus 60', and also provides a means for conveniently lifting the entire apparatus 60' and attaching the arm assembly 110'.
is in the rest position and there is a possibility that the cable 30 may slack, the entry section 90 of the cable is removed from the upper pulley 1.
02' acts as a guiding device to hold it in the proper relationship.

7 and 8, one end of the torsion element is fixed to a rotatable arm, the other end of the torsion element is attached to a fixed frame, and torsional shear is applied in the axial (longitudinal) direction of the torsion element. Figure 3 shows a further embodiment of the invention which differs significantly from the previous two embodiments in that it takes advantage of the elastic damping effect of the dispensing cylindrical body. In contrast, the embodiments shown in FIGS. 7 and 8 use differently shaped elastic torsion elements in the form of tapered discs, which significantly taper the thickness of the disc from its hub to the periphery. The shearing effect is uniform throughout the elastic material because the shear strain is distributed radially from the hub near the axis of the disk to the circumferential portion around the disk. The former type of shear can be considered "longitudinal torsional shear," whereas the latter type of shear can be referred to as "radial torsional shear."

As in the previous embodiment, the upper sheave 10
2'' and a lower sheave 108'', each of said two sheaves being pivotally connected to opposite ends of the arm assembly by an upper pivot pin 116'' and a lower pivot pin 118'', respectively, so that the 2'' of tugs 102″, 10
8'' are rotatable about their respective axes and parallel to an axis 132'' which intersects the arm assembly 110'' in the region between the two sheaves.

The left tapered disk-like elastic element 200 is attached to the left plate 112'' of the rotatable arm 110'' so that the hub portion 202 of the elastic element 200 aligns with the main axis of the tensioner as the arm assembly 110'' rotates. Rotates around 132″.
The peripheral portion 204 of the resilient device 200 is secured by a peripheral strap 208 secured to the corresponding left side frame 124'' by suitable bolts or other attachment devices 210.
Similarly, a generally identical tapered disc-like resilient element 206 secures its hub portion to the right side plate 114'' of the arm assembly and its peripheral portion to the second
The elastic element 20 is secured to the right side frame member 130'' by an attachment strap 208 on the right side of the tensioning device.
0,206 each include a plurality of tubular reinforcing elements 2 each concentric about the axis 132'' of the tensioning device.
12 are provided.

The operational characteristics of the rope tensioning device constructed according to the present invention are shown in the geometrical diagrams shown in FIGS. 9 to 14,
The following description will be made with particular reference to the graph of FIG.

9 to 14 schematically illustrate a typical rope tensioning device 60, 60' or 60'' according to the invention, with arms 110, 110',
110'' and the outward direction of the ropes 80 and 90 are -30 degrees (Fig. 9), zero degrees (Fig. 10), 15 degrees (Fig. 11), and 45 degrees (12 degrees), respectively.
), 90 degrees (Figure 13) and 120 degrees (Figure 14)
It is rotating.

Referring specifically to FIG. 9, FIG. It can be seen that the portions of the rope 30 (including the lower exit portion 80 exiting the tensioning device on the way there) are shown schematically. Both upper and lower sheaves 102 and 108 have the same radius "R" and are spaced apart from each other along rotatable arm 110 by a distance "A". Inlet part 90 and outlet part 80 of cable 30
During the intended use of the cable tensioning device (see Figure 1), it is oriented generally horizontally, so that the tension " It can be seen that a torque couple of magnitude equal to "T" is applied to the rope tensioning device. 9 to 14 correspond to the rope tensioning device of the present invention in which the arms are used at various angles of inclination with respect to the vertical direction. Overall, however, the tension T is not necessarily applied to the tensioning device horizontally, and the crossing angle is relative to a line perpendicular to the direction of the entry and exit portions 90 and 80 of the rope (or If the parts of the rope are not parallel they are measured (with respect to a line perpendicular to half the angle between them).

No. 9 showing the geometrical characteristics of the rope tensioning device when the arm is tilted 30 degrees backward from the vertical direction.
With particular reference to the figures, the vertical distance V is the arm 110
slightly less than in the case shown in FIG. 10, where the is oriented vertically. If you do simple geometric arithmetic, you can get to number 10.
The vertical distance V in the figure is equal to 2R+A, while in FIG. 9 it is shown to be equal to 2R+Acos (30°).
Furthermore, the effective length of the cable 30 is between the minus θ radian position shown in FIG. 9 and the 0 position shown in FIG. 10 (or between ₀ and plus θ radian) _. It increases by the amount of (θ).

Referring to FIG. 11, where the arm 110 is oriented at an angle of plus 15 degrees to the vertical, the vertical distance V is equal to 2R + Acos (15 degrees), while the effective length of the cable 30 is also (1/6πR ) has increased.

As a result of continuous increase in tension T, arm 1
If we perform the corresponding calculations corresponding to Figures 12 and 13, which show that 10 has been rotated further, the corresponding vertical distances V are Acos (45°) + 2R and 2R, respectively.
, while the corresponding elongation S is Asin
(45°)+1/2πR and A+πR.

Referring to FIG. 14, the tension of the cable 30 is increased to the point where the angle increases to 120 degrees, i.e. 109 as recalled (at least for the numerical examples given with respect to the embodiments shown in FIGS. 2 and 3).
It can be seen that the normal maximum rotational deflection in degrees has increased to a value beyond the normal operating range of the elastic torsion element. In any case, the vertical distance V is 2R−Asin
(30°), and the elongation S is (4/3)
It is πR.

Referring to FIG. 15, each of the four curves indicates that the arm 110 is at rest (i.e., the cable 3
0 tension T is zero) and the initial slope is -30 degrees (lower curve 300), zero (curve 302), plus 15 degrees (curve 304) and plus 45 degrees (curve 306). 2 is a graph illustrating the operating characteristics of a rope tension damper using elastic torsion elements each corresponding to the operating characteristics of the rope device 60 and subjected to a longitudinal torsional shearing action; These curves are shown in Figures 9, 10 and 1.
1 and 12, respectively, correspond to the geometrical shapes shown diagrammatically in FIG. Therefore, the first curve 30
If 0 is the straightest line and approximately 50 metric tons of tension is applied to cable 30, the vertical distance S will be approximately 4 meters (or conversely, if approximately 50 metric tons of tension is applied, the vertical distance S will be approximately 4 meters). It can be seen that Contrasting 0 degree curve 3
02 starts to rise rapidly when the vertical distance S exceeds 3 meters and/or when the tension T exceeds 40 tons. The 15 degree curve 304 rises rapidly even if the vertical distance S and/or tension T is even smaller. The 45 degree curve 306 is even more extreme. Horizontal dotted line 308, which equates to approximately 65 metric tons, and vertical dotted line 310, which equates to just over 3 meters, shows a typical set of design parameters. From various graphs, the initial direction of arm 110 is 0 degrees and plus 15 degrees.
Angles intermediate to 100° will provide a smooth transition condition that results in a significant increase in resistance as the design parameters are reached, but the operating parameters are limited so as not to result in an excessively rapid increase in tension T. It can be seen that some additional vertical distance is acceptable if there is.

Although three embodiments of the novel rope tension shock absorber have been described in detail, in the light of the foregoing description, it will be appreciated by those skilled in the art that there may be other variations without departing from the various inventive concepts that form the basis of the present invention. Obviously, modifications and other embodiments may be made. Accordingly, it is intended that the invention cover such alternatives, modifications, and variations as come within the spirit and broad scope of the claims.