COMPOSITE LEAF SPRING EYE DESIGN AND PRODUCTION METHOD

TECHNICAL FIELD

The invention is related to the design of the eye part (the hinged part where the leaf spring is coupled to the vehicle) of the leaf springs that are made of composite material which are used in the automotive sector or railway transportation (heavy duty or light vehicles or automobiles etc.) and the production method thereof. (Similar hinge connections are present in the swings of the front wheel systems of automobiles. A production and design similar to a hinge system can be performed herein.)

PRIOR ART

Leaf springs can be used in all kinds of vehicles (crane-neck phaeton, trains, automobiles, heavy duty or light commercial vehicles etc.) The invention is usually used in the automotive sector; therefore the description will be made with reference to the automotive sector.

The leaf springs used in the automotive sector are produced from alloy steel materials by carrying out hot or cold production methods (rolling, bonding etc.) There are different types of leaf spring eye designs as there are different types of leaf springs. Leaf spring types are divided into two main groups, being parabolic and conventional. (Parabolic type leaf spring section thicknesses differ towards the lengths of the leaf springs, whereas the section thicknesses in conventional leaf springs are fixed. Both types can be formed of more than one piece (layers)). Figure-1 illustrates different eye types. In figure 1 , a normal eye (1.a), a reverse eye (1.b) and a Berlin eye (1.c) can be seen (the phrase“Berlin” in“Berlin eyes” is a general name given to said structure).

The mounted position of the leaf spring on the vehicle and the movement type during operation can be described as below;

A leaf spring front eye (2.5.1 ) is mounted to the fixed shackle located on the vehicle chassis (2.8) similar to the one in Figure 2 and a leaf spring back eye (2.5.2) is attached to the leaf spring shackle (2.4). A“U” connection means (2.2) is clamped to the vehicle axle (2.1 ) and the leaf spring (2.5) is mounted to its place on the vehicle.

The eye types can be seen in Figure - 3 such that the leaf spring (2.5) on the vehicle is dismantled from its place. The front bush (3.1. a) that is placed inside the front eye (2.5.1 ) and the back bush (3.1.b) that is placed inside the back eye (2.5.2) can be seen. The front bush (3.1. a) and the back bush (3.1.b) are mounted into their places on the leaf spring (2.5) and the front eye (2.5.1 ) of the fixed shackle eye hinge screw (3.3) is attached to the fixed shackle (2.6) by being passed through the hinge hole (2.6.1 ) located on the fixed shackle in order for the leaf spring (2.5) be formed as seen in Figure 2. Similarly the back mounting point hinge screw (3.4) of the back mounting point (2.7) can be attached to its place on the leaf spring shackle (2.4) back mounting point (2.7) by being passed from the back mounting point hinge hole (2.7.1 ) and at the same from the leaf spring shackle hinge hole (2.4.2). Similar to the front eye (2.5.1 ) after the back eye bush (3.1.b) is attached to the back eye (2.5.2) the back eye (2.5.2) is aligned with the leaf spring shackle eye part (2.4.1 ) and the leaf spring shackle eye hinge screw (3.2) is passed through the leaf spring shackle eye part hole (2.4.1. a) thereby enabling the attachment of the back eye (2.5.2) and the leaf spring shackles (2.4) to each other.

Figure-4 shows the movement direction (3.5) of the vehicle. For this reason, the eye at this section is called the front eye (2.5.1 ) and the eye at the other section is called the back eye (2.5.2).

When the vehicle is travelling on the road, if the wheel (2.3) encounters a pit, the leaf spring shackle (2.4) rotates around the back mounting point hinge screw (3.4) at a clockwise direction during the downward movement (4.1 ) of the wheel and therefore the leaf spring (2.5) is contracted and it takes the form shown in figure 4. At the same time, although the front eye (2.5.1 ) rotates around the fixed shackle eye hinge screw (3.3) at a clockwise direction, the back eye (2.5.2) rotates at an anti-clockwise direction around the leaf spring shackle back hinge screw (3.2) relative to the leaf spring shackle (2.4).

When the wheel (2.3) in figure 5, encounters a bump on the road, the upward direction movement (5.2) of the wheel, the leaf spring shackle (2.4) rotates in an anti clockwise direction around the back mounting point hinge screw (3.4) and the leaf spring (2.5) stretches (elongates) and is enabled to take the form shown in Figure-5. At the same time, although the front eye (2.5.1 ) rotates around the fixed shackle eye hinge screw (3.3) at an anti-clockwise direction, the back eye (2.5.2) rotates at a clockwise direction around the leaf spring shackle hinge screw (3.2) relative to the leaf spring shackle (2.4). The operation of the leaf spring system has been described in Figure-4 and Figure-5.

As the leaf spring carries all of the weight loaded on the axle of the vehicle under the vehicle, and therefore this spring has been produced from steel alloy material for it to be durable, and as a result the spring is quite heavy. (The weights of said springs can be as heavy as the weight of an adult).

As it moves by continuously bending, the material is fatigued and small fractures occur therein, and as a result breakages occur. (It has a certain life span).

(The reason for the mounting of the bushes (3.1. a) (3.1.b) inside the front eye (2.5.1 ) and the back eye (2.5.2) is that, the eyes (2.5.1 ) (2.5.2) of the spring may be damaged due to friction if the bushes (3.1. a) (3.1.b) were not present inside these eyes, as the front and back eyes (2.5.1 ) (2.5.2) move at a clockwise and anti clockwise direction under the weight loaded on the axle (2.1 ) of the vehicle, during the down (4.1 ) and up (5.1 ) movement of the wheel (2.3). Moreover the bush materials, in some cases may comprise rubber (rubber material can be found between the two telescopic pipes (is available in the market)). It is aimed for the sudden effect on the eye hinges of the impact loads occurring due to the sudden movements of the wheel to be prevented).

As fuel saving is tried to be achieved in the vehicle section in the recent years, the vehicle manufacturers have been trying to produce vehicle parts that are lighter in weight and more durable. Leaf springs are one of these materials. For this reason, composite materials are trying to be used and studies regarding this issue are being continued. (Composite: Materials that are formed by combining at least the two best features of two different material groups or to establish a new feature which is not present in both materials by bringing together said materials. In other words composite materials are materials that are formed of different types or phases of materials where the weak aspects of both materials are corrected or the superior features thereof are increased.)

Some of the examples of composite materials that are used in the automotive sector are; carbon fiber-epoxy, fiberglass-polyester, fiberglass-epoxy, Kevlar-epoxy etc. (These and other similar material pairs are used in the manufacturing sector of vessels and primarily the automotive sector). (Carbon fiber, glass fiber, Kevlar materials are materials that are highly resistant to longitudinal tension forces which are formed of hair thin fibers. The direction of the fiber direction inside the materials in order to obtain parts produced from such materials, need to be placed such that the load on the part must be met towards the direction of the fiber.

These types of fibers are called fiberglass fabric (they may have a knitted structure such as that of knitted sweaters), Kevlar fabric or carbon fiber fabric (cloth)).

Parts that are extremely durable can be produced and used in the automotive industry by means of combining these material pairs. (Several techniques related to the production of such parts using these materials are present. The subject of the invention is not a novel production method but how the design subject to the invention can be produced using available production techniques.) (There are several production methods present, some of these are; RTM (resin transfer molding), Pre-preg (the production of composite materials by a chemical reaction of the resin with thermal methods (etc.) where the pre-resin fiber fabrics are placed inside the mold of the desired product))

Several scientific studies and patents related to the production techniques and usage of composite materials are available regarding the leaf spring field.

One of these scientific studies is a publication where a type of leaf spring is examined using glass fiber -epoxy, written by Erol Sancaktar and Mathieu Gratton, published by“Elsevier”. (Publication date: Composite structures 44/1999/195-204) (The title of the article“Design, analysis, and optimization of composite leaf springs for light vehicle applications”). In this article the necessity of positioning the glass fibers at the direction of the leaf spring during leaf spring production, in order to meet the inner tensions at this direction is described as the leaf spring stretching is realized at the longitudinal direction of the leaf spring.

In order to understand composite materials we can think of a structure formed of concrete and steel rods used in constructions. The weight load on the concrete is carried on the steel rods along the longitudinal direction of the steel rods. If these steel rods are not continuous (broken or cut off) inside the structure the structure cannot carry the loads thereon and this may lead to breakages or malformation. As such, composite materials function like the steel rods in construction. If the fibers inside the composite structure are broken or cut off, they will not be able to carry the weight along the longitudinal direction of the fiber. As a result the part made of composite material may be damaged. Some of the related application patent files are GB2366350A, JP2000018299A,US4969633A,US2005051933A1 ,US2005051934A1 ,WO2011056553A2, WO2011103857A1 ,WO2012075582A1 ,EP0994270A2.

The subjects described in these patents have similarities to this disclosure. However this relation is related to providing a design with composite materials similar to the eye design of the steel leaf springs that are already used. In the patent numbered

WO2011103857A1 a method that has been arranged for an eye design similar to the eye design found in steel springs. In the patent numbered WO2012075582A1 a part that may be produced from a composite material or any other material is mounted to the end of the composite spring end, with screws after a hole is opened into said end, in order to obtain a similar design to the steel eye design mentioned in the patent numbered WO2011103857A1.

The holes opened into the composite material or the cuts thereof may damage the integrity of the fiber (when the composite leaf spring is operated under the vehicle) and therefore the structure may be damages and the usage life of the leaf spring may shorten. (Especially in the invention with the patent numbered WO2012075582A1 the holes opened at the end of the composite material during the screwing of the eye to the composite material that is mounted to the end of the leaf spring).

A similar disadvantageous situation also occurs in the patent numbered WO2011103857A1. Although in the patent numbered WO2011103857A1 a material is added to the cut sections at the end in order to provide integrity, the fiber integrity still has been damaged and therefore the durability of the material is reduced.

OBJECTS OF THE INVENTION

The aim of the invention is to provide a composite leaf spring that does not limit the movements of the leaf spring at its working medium, where the composite leaf spring eye part is designed without disrupting (cutting, piercing etc.) the fiber integrity inside the leaf spring.

Another aim of the invention is to enable higher amounts of production of the composite leaf spring eye design subject to the invention at a certain period of time.

DESCRIPTION OF THE FIGURES

The characteristic and structural features of the invention and all of its advantages shall be understood more clearly by means of the figures given below and referring to said figures and the detailed description below, and therefore any kind of evaluation must be carried out by taking into consideration these figures and detailed description.

Figure-1 : Leaf spring eye types

Figure-2: The position of the leaf springs under the vehicle, on the wheel axle and chassis

Figure-3: The mounting type of the leaf spring onto the chassis under the vehicle

Figure-4: The position that the leaf spring has taken under the vehicle by moving of wheel in a downward direction

Figure-5: The position that the leaf spring has taken under the vehicle by moving of wheel in an upward direction

Figure-6: The type of mechanical hinge connection of the pelvic bone to the femur bone in the human skeletal system.

Figure-7: The general view of the mechanical hinge connection subject to the invention Figure-8: The winding type and method of the fiber mesh at the eye region for the design of the composite leaf spring subject to the invention.

Figure-9: The alternative winding type and method of the fiber mesh at the eye region for the design of the composite leaf spring subject to the invention.

Figure-10: The general production technique of the composite leaf spring subject to the invention Figure-11 : The general view of the protective parts that resemble the letter“C” which only reduce frictional damage and which both reduces frictional damage and provides shock absorbance, which can be mounted on the composite leaf spring eye section subject to the invention.

Figure-12: The general view of the produced composite eye after the“C” shaped piece which only reduces friction damage is mounted to the composite leaf spring eye part. Figure-13: The general view of the produced composite eye after the“C” shaped piece having a shock absorbing material and which reduces friction damage, is mounted to the composite leaf spring eye part.

Figure-14: The general view of the bush having shock absorbing material which resembles the letter“C” that may function as a shock absorber at the area where the eye is installed to the vehicle after the friction damage reducing part resembling the letter“C” is attached only to the composite leaf spring eye part.

Figure-15: The general view of the attachment of the bush having shock absorbing material similar to a “C” shape, which can function as a shock absorber and the composite leaf spring having only a friction damage reducing“C” shaped part mounted onto the composite leaf spring eye which has been attached onto the fixed shackle that is shaped like a“C” on the vehicle.

Figure-16: The general view of the attachment of the composite leaf spring onto the fixed shackle having a“C” shape on the vehicle, where the leaf spring has a“C” shaped both shock absorbing and friction damage reducing “C” shaped part comprising shock absorbing material, that is attached to the composite leaf spring eye part.

Figure-17: The general view of the composite leaf spring back eye, subject to the invention having a“C” shaped part at the end that is attached to the leaf spring shackle. Figure-18: The general view of the covers attached to the fixed shackle in order to prevent the composite leaf spring subject of the invention from being detached at the direction in which it has been coupled to the fixed shackle.

Figure-19: The position that the leaf spring subject to the invention has taken under the vehicle by moving of wheel in a downward direction

Figure-20: The position that the leaf spring subject to the invention has taken under the vehicle by moving of wheel in an upward direction Description of the reference numbers in the Figures

1.a) Normal eye

1.b) Reverse eye

1.c) Berlin eye

2.1 ) Axle

2.2) U-clamping of the leaf spring to the axle (U screws)

2.3) Wheel

2.4) Leaf spring shackle

2.4.1 ) Leaf spring shackle eye part

2.4.1.a) Leaf spring shackle eye part hole

2.4.2) Leaf spring shackle top hinge hole

2.5) Leaf spring

2.5.1 ) Front eye

2.5.2) Back eye

2.6) Front fixed shackle

2.6.1 ) Hinge hole on the fixed shackle

2.7) Back mounting point

2.7.1 ) Back mounting point hinge hole

2.8) Vehicle Chassis

3.1.a) Front bush

3.1.b) Back bush

3.2) Leaf spring shackle eye hinge screw

3.3) Fixed shackle eye hinge screw

3.4) Back mounting point hinge screw

3.5) Vehicle movement direction

4.1 ) Downward direction

5.1 ) Upward direction

6) Human skeletal femur and pelvic bone section

6.1 ) Pelvic bone

6.2) Femur bone

6.3) Spherical femur bone cap 6.4) Spherical femur bone cap articular cartilage

6.5) Pelvic bone acetabulum joint (The“C” shaped area where the femur cap is attached)

6.6) Acetabulum articular cartilage.

6.7) The force directions of the body weight of a human, transferred to the capitulum of the spherical femur bone from the acetabulum

7) Cylindrical hinge system

7.1 ) Cylindrical“C” bearing

7.1 G)Cylindrical“C” bearing width

7.2) Cylindrical hinge

7.3.1 )“C” bearing top alpha angle

7.3.1.a) The top end of the“C” bearing

7.3.2)The bottom beta angle of the“C” bearing

7.3.2. a) The bottom end of the“C” bearing

7.3.3)“C” bearing 180° capitulum angle

7.3.3. a)“C” bearing capitulum end

7.5) Cylindrical axis

7.7.1 )“C” bearing capitulum angle reaction forces

7.7.2)“C” bearing top angle reaction forces

7.7.3)“C” bearing bottom angle reaction forces

7.8) Cylindrical“C” bearing reverse direction

7.9) Cylindrical“C” bearing direction

8.K) North section of the composite leaf spring eye

8.K) South section of the composite leaf spring eye

8.B) First stage

8.C) Second stage

8.D) Third stage

8.E) Fourth stage

8.M) The center of the eye wound with fiber fabric having north-south section

8) Eye wound with fiber fabric having north-south section

8.1 ) Fiber fabric at the south section

8.2) Fiber fabric at the north section 8.3) The end point where the fiber fabric at the from the north section passes the north section and reaches the south section

8.4) The fiber fabric end point of the south section at the second stage

8.5) The fiber fabric end point of the north section at the second stage

8.6) The fiber fabric end point of the south section passing from the second stage to the third stage

8.7) The fiber fabric end point of the north section passing from the second stage to the third stage

8.8) The fiber fabric end point of the south section at the third stage

8.9) The fiber fabric end point of the north section at the third stage

9.B) Alternative winding first stage

9.C) Alternative winding second stage

9.D) Alternative winding third stage

9) Eye wound with fiber fabric thereon

9.1 ) Alternative winding fiber at the south section

9.2) Alternative winding fiber at the north section

9.3) The end point where the eye having fiber fabric wound thereon passes from the north section and becomes the fiber fabric of the south section

10.M) Fiber fabric bobbin

10.F) Fiber fabric

10. FG) Fiber fabric width

10.K) Mold width

10.C) Eye protector width

10) Leaf spring with composite cylinder hinge

10.G) Entrance point of the fiber to the composite leaf spring

10.V) Leaf spring width having composite cylinder hinge

10.1 ) Eyes wound with fiber

10.2) Bottom mold

10.3) Top mold

10.3.1 ) The fiber movement direction of the fiber from the fiber bobbin to the composite leaf spring

10.3.2) The fiber travelling direction of the fiber to the eye at the fiber bobbin direction 10.3.3) The travelling direction of the fiber towards the other eye

10.3.4) The travelling direction of the fiber passing from the other eye to the fiber entrance point

10.4)“C” shaped eye protector

11.1 )“C” shaped friction damage reducing eye protector

11.1 P) Rough inner surface

11.2)“C” shaped friction damage reducing eye protector with shock absorbing material

11.3) External“C” shaped protector part

11.4) Internal“C” shaped part

11. D) Shock absorbing intermediary material

12) Composite leaf spring cylindrical hinge with“C” shaped eye protector having friction damage reducing features

12.1 ) Resin

13)Composite leaf spring cylindrical hinge with“C” eye protector having friction damage reducer and shock absorbing features

14)“C” bush with shock absorbing material

14.1 )“C” bush internal part with shock absorbing material

14.2)“C” bush external part with shock absorbing material

14.3) Screw hole on the“C” bush with shock absorbing material

15) Cylindrical“C” bearing fixed shackle

15.1 ) Screw

15.2) Screw hole on the cylindrical“C” bearing fixed shackle

17) Leaf spring shackle with cylindrical“C” bearing

17.1 ) Leaf spring shackle cylindrical“C” bearing

18.1 ) Left cover

18.2) Right cover

18.3) Left cover screw

18.4) Right cover screw

18.5) The holes into which the left cover screws shall be inserted, which are found on the fixed shackle onto which the composite leaf spring shall be mounted on

18.6) The holes into which the right cover screws shall be inserted, which are found on the fixed shackle onto which the composite leaf spring shall be mounted on 19.1 ) Composite eye with front cylindrical hinge with fiber fabric winding

19.2) Composite eye with back cylindrical hinge with fiber fabric winding

DESCRIPTION OF THE INVENTION

A similar type to the hinge (similar to the eye design) subject to the invention can be seen in the human skeletal system shown in Figure 6, in order for the invention to be understood more clearly. In Figure 6, the human pelvic bone (6.1 ), femur bone (6.2), the semi spherical hollow acetabulum (6.5) to which the spherical femur bone cap (6.3) is attached at the pelvic bone (6.1 ) femur bone cap (6.3) (acetabulum; is the phrase given to this section (in medicine)) articular cartilage (6.5.1 ) in the acetabulum, and articular cartilage on the spherical femur bone cap (6.3.1 ).The downward force due to the weight of a person, transfers the forces on charge (6.7) that are reflected from the whole surface of the hollow half globe shaped acetabulum via the pelvic bone (6.1 ) to the spherical femur cap (6.3) that is attached into the acetabulum (6.5). The articular cartilages (6.3.1 )(6.5.1 ) herein have been provided in order to prevent the abrasion that may arise due to the friction as a result of the motion between the spherical femur bone cap (6.3) and acetabulum (6.5). As this connection is spherical the femur (6.2) bone can move in all directions (spherical rotation). (Figure-6 is the section view of the spherical hinge in the human skeletal system).

In figure 4 and 5 of the known state of the art, the front eye (2.5.1 ) and the back eye (2.5.2) of the leaf spring move in a clockwise direction or anti-clockwise direction at a single axis during the upward (4.1 ) and downward directed (5.1 ) motion of the wheel

(2.3).

As in the single axis clockwise or anti clockwise rotation of the leaf spring eyes (2.5.1 )(2.5.2), the composite leaf spring eye design subject to the invention also should allow this motion without disrupting the continuity (piercing, cutting etc.) of the fibers located inside the composite leaf spring.

The cylindrical hinge system (7) of Figure-7, similar to the spherical femur cap

(6.3) and spherical hinged acetabulum (6.5) pair in Figure-6, have been applied to the composite leaf spring eye design.

In figure 7, a cylindrical“C” bearing (7.1 ) in exchange for the acetabulum (6.5) in Figure 6, and cylindrical hinge (7.2) in exchange for the spherical cylindrical femur cap (6.3) has been provided. As the hinge is cylindrical, it can rotate in a clockwise direction or anticlockwise direction only around the cylindrical axis (7.5). In Figure 6, in order for the end of spherical femur cap (6.3) of the human skeletal system which is located inside the pelvic bone (6.1 ) not to be dislocated from the acetabulum (6.5) it is connected with muscles from the femur (6.2) to the pelvic bone (6.1 ). (In figure-6 the positions of the muscles has not been shown, as it depicts the skeletal system and as the view of the spherical connections in the human skeletal system is generally known).

In Figure -7, the“C” bearing top end (7.3.1. a) and bottom end (7.3.2. a) sections opposite the top alpha angle (7.3.1 ) and the bottom beta angle (7.3.2) of the cylindrical “C” bearing have been provided instead of the femur (6.2) being connected to the pelvic bone by muscles in the cylindrical“C” bearing (7.1 ).

As a result, if the cylindrical“C” bearing is pulled in a reverse direction (7.8) while the cylindrical hinge (7.2) is rotating around the cylindrical axis (7.5),“C” bearing top angle reaction forces (7.7.2) are established on the entire surface along the width (7.1.G) of the cylindrical“C” bearing on each angle range at the entire alpha angle (7.3.1 ) at the end of the top end (7.3.1. a) of the“C” bearing. According to a similar description,“C” bearing bottom angle reaction forces (7.7.3) are obtained on the entire surface along the width of the cylindrical“C” bearing at each angle range at the entire beta angle (7.3.2) at the bottom end (7.3.2. a) of the“C” bearing. (The top and bottom angle reaction forces (7.7.2)(7.7.3) at only one angle range, has been shown.)

Moreover in Figure 6, forces similar to the affecting forces (6.6) from the entire surface of the acetabulum are formed.

The top angle reaction forces (7.7.1 ) (only the top angle reaction force (7.7.1) in a single angle range has been shown) on the entire surface along the width (7.1.G) of the cylindrical “C” bearing in each angle range at the 180° head angle (7.3.3) of the cylindrical“C” bearing is formed as follows; if the cylindrical hinge (7.2) is pushed at the direction of the cylindrical“C” bearing direction (7.9) when it is rotating at a clockwise or anti-clockwise direction around the cylindrical axis (7.5) reaction forces at the opposite direction will be formed.

The top end (7.3.1. a), bottom end (7.3.2. a), head end (7.3.3. a) of the cylindrical “C” bearing sections that prevent the cylindrical hinge (7.2) which carries the reaction forces (7.7.1 ) (7.7.2) (7.7.3) that are formed, from being dislocated from the cylindrical“C” bearing, the cylindrical“C” bearing may be formed as a single body as shown in Figure 7, but it may also be mounted to each other.

When the cylindrical“C” bearing (7.1 ) cylindrical hinge (7.2) pair in Figure 7, is pulled from or pushed towards the cylindrical“C” bearing direction (7.9) or at a reverse direction (7.8), this will enable rotation around the cylindrical axis (7.5) at a clockwise or anti clockwise direction and said pair will not separate from each other. If the cylindrical hinge (7.2) is pulled at an opposite direction to the cylindrical“C” bearing at a cylindrical axis direction (7.5), the pair will separate from each other. In order to prevent this from happening the limiting means which shall prevent the movement in this direction, can be used together with the cylindrical hinge system (7). (This situation has been described as a left cover (18.1 ) and right cover (18.2)). However the movement in this direction can be prevented with any other kind of method.)

When the leaf spring is being produced from composite materials, the front and back eyes (2.5.1 )(2.5.2) of the leaf spring shall be designed to be similar to the cylindrical hinge (7.2) shown in Figure 7and the front fixed shackle (2.6) and the back leaf spring shackle (2.7) shall be designed to be similar to the cylindrical “C” bearing. For this reason, when the composite leaf spring (10) (In figure -10) was being produced, the north-south, wound eye (8) (an alternative winding is shown in Figure 9) in Figure 8, has been formed to be similar to the cylindrical hinge (7.2).

The north-south wound eye (8) in Figure 8 (the fiber fabric, can be formed by winding manually and/or by a machine which will be described below) is shaped like a mushroom, or like the shape of an explosion after an atom bomb, and the fiber winding stages are the first stage (8.B), second stage (8.C), third stage (8.D) and fourth stage (8.E). (The number of stages mentioned here can be completely changed. The important thing is to form a north-south wound eye). North section fiber fabric (8.2) is found at the north section (8.K) and the south section fiber fabric (8.1 ) is found at the south section (8.G). The end point (8.3) where the fiber fabric at the north section passes to the south section and becomes the fiber fabric of the south section (The fiber fabric may be disrupted at this point. The north fiber fabric and the south fiber fabric can be completely apart from each other) is located at the first stage (8.B). The end point (8.3) at the first stage (8.B) ends at the second stage (8.C) and the north section fiber fabric end point (8.5) and the south section fiber fabric end point (8.4) is formed. The north section fiber fabric end point (8.7) that is passing from the second stage to the third stage is further north from the initially formed north section fiber fabric end point (8.5) that has been formed in the second stage, similarly the south section fiber fabric end point (8.6) that is passing from the second stage to the third stage is located further south from the south section fiber fabric end point (8.4) that has been formed in the first stage.

In the third stage (8.D), the north point (8.7) at the end of the second stage forms the north section fiber fabric end point (8.9) of the third stage by curls on itself in clockwise direction, and similarly the south point (8.8) at the end of the second stage curls on itself at an anti-clockwise direction to form the south section fiber fabric end point (8.8) of the third stage. Following this stage sufficient (according to the desired size of the north-south wound eye (8)) winding is carried out and the north-south wound eye (8) can be formed. The north section fiber fabric (8.2) and the south section fabric (8.1 ) come together towards the center of the finished, north-south wound eye (8.M) and this fabric is clamped between half the eye at the north section (8.K) and the part located in the south section (8.G). When resin is added to the fiber fabric mentioned, (adhesive resin that is used in the production of composite materials) this reinforces the physical integrity of the eye (8) and the composite cylindrical hinge leaf spring (10).

(In the patent numbered WO2011056553A2, the composite leaf spring design, the fabric which is wrapped around the eye as seen in Figure 7 of the mentioned patent, is separated into two when the fiber fabric reaches the eye section. In such a case even though fiber fabrics are adhered together by resin, the top and bottom fiber fabric can be separated from each other from the adhered sections).

An alternative winding technique has been shown in Figure 9. Stages similar to the winding technique of Figure 8 is provided herein, which are, alternative winding first stage (9.B), alternative winding second stage (9.C), alternative winding third stage (9.D). In the north section (8.K) the alternative wound north section fiber fabric (9.2) is found and in the south section (8.G), the alternative wound south section fiber fabric (9.1 ) is found. The end point (8.3) where the fiber fabric at the north section passes to the south section and becomes the fiber fabric of the south section (The fiber fabric may be disrupted at this point. The north fiber fabric and the south fiber fabric can be completely apart from each other) is located at the first stage (9.B). In the first stage (9.B) the end point (9.3), becomes the north section fiber fabric end point (8.5) in the alternative winding second stage (9.C), and a fiber fabric wound eye (9) can be formed thereon by means of carrying out the required amount (according to the preferred size of the fiber fabric wound eye (9)) of winding at the clockwise direction.

The fiber fabric (10.F) that exits out of the fiber fabric bobbin (10.M) during the composite cylindrical hinged leaf spring (10) in Figure 10, enters from the entrance point (10.G) of the fiber to the composite leaf spring, along the travelling direction (10.3.1 ) of the fiber from the fiber bobbin to the composite leaf spring, in order to form the cylindrical hinged leaf spring. Following this, the fiber fabric is wound along the entrance direction

(10.3.2) to the eye towards the fiber bobbin, and the fiber wound eye (10.1 ) at this direction is formed. Following this the fiber fabric moves along the travelling direction

(10.3.3) towards the other eye and the other fiber wound eye (10.1 ) is formed, and after this the fabric moves towards the fiber entrance point (10.3.4) and exits there-from; wherein the production of the cylindrical hinged composite leaf spring is completed without the fiber fabric (10.F) being discontinued. (The process is continuous, as the north and south section fiber fabrics (8.2)(8.1)(9.1 )(9.2) are not disrupted at the end point

(8.3) during the first stage (8.B) in the north-south section fiber fabric wound eye (8) and at the end point (8.3) during the first stage (9.B) in the fiber fabric wound eye (9) where the fabric is wound around the eye itself, and therefore the fiber fabric (10.F) which exits out of the fiber fabric bobbin (10.M) can form both fiber wound eyes (10.1 ) on the composite cylindrical hinged leaf spring (10) continuously.)

In order to reduce the friction that occurs during the movement of the femur bone (6.2) in the human skeletal system, an acetabulum articular cartilage (6.6) and spherical femur bone cap articular cartilage (6.4) is present. Similarly, during the composite cylindrical hinged leaf spring production“C” eye protectors (10.4) are placed as top and bottom molds (10.2) (10.3) before the mold is closed (before the resin is cured (sets) inside the mold), on the fiber wound eyes (10.1 ) in order to prevent-reduce friction that occurs inside the cylindrical“C” bearing (7.1 ) of the fiber wound eyes (10.1 ) that are formed in the eye area of the composite leaf spring. When the composite cylindrical hinged leaf spring (10) production is finished and it is extracted out of the mold (10.2)

(10.3), the“C” eye protectors (10.4) shall be formed as a whole, such that they are stuck (they will not be able to be dismantled without damaging the composite leaf spring) on the fiber wound eyes (10.1 ). During production, the composite cylindrical hinged leaf spring width (10.V) is related to the fiber fabric width (10. FG). When more than one composite cylindrical hinged leaf spring (10) production is to be carried out, the fiber fabric width (10. FG) shall be determined as the total width, and composite leaf spring (10) having a width that is as wide as the total width shall be wound in one go, and the eye protector width (10.C) shall be similar to the total width and they will be placed on the fiber wound eyes (10.1 ) and the mold width (10.K) shall be adjusted suitably and following this the production will be carried out. In short, there is a mathematical-measuremental relationship between the fiber fabric width (10. FG), mold width (10.K), eye protector width (10.C) and composite cylindrical hinged leaf spring width (10.V). By means of the relationship (like slicing bread) the desired numbers of composite cylindrical hinged leaf spring (10) can be formed by cutting in the longitudinal direction.

The“C” eye protector (10.4) designs can basically be formed in two ways. In Figure-11 as a“C” eye protector (10.4), friction damage reducing“C” eye protector (11.2) having shock absorbing material together with friction damage reducing“C” eye protector

(11.1 ) can be seen. Both protectors (11.1 ) (11.2) have a rough inner (11.1 P).

In figure 12, friction reducing“C” eye protector (11.1) has been placed on the north-south sectioned fiber fabric wound eye (8) whose production has been completed and it has been made similar to the cylindrical hinge (7.2) together with the resin (12.1 ).

Similarly in figure 13, a friction reducing“C” eye protector (11.2) having shock absorbing material has been placed on the north-south sectioned fiber fabric wound eye (8) whose production has been completed and it has been made similar to the cylindrical hinge (7.2) together with the resin (12.1 ).

As the rough inner surface (11.1.P) located in both types of eye protectors (11.1 )

(11.2) are completely filled with resins (12.1 ), the eye protectors that reduce frictional damage (11.1 )(11.2) ensure the fixation of the eyes as shown in figure-12 and figure-13 and prevent them from being dislocated.

The“C” eye protector (11.2) having shock absorbing material which only reduces friction damage, comprises shock absorbing material between the two telescopic“C” parts (11.3)(11.4). (The external“C” protecting part (11.3) is integral with the inner“C” part (11.4) and the shock absorbing intermediary material (11.D). It has already been explained why rubber bushes were required in the known state of the art. The shock absorbing material has been used for similar purposes.)

(In figure-14, the “C” bush (14) with shock absorbing materials, has shock absorbing materials (11.D) between the internal and external parts (14.1 ) (14.2)).

According to the composite leaf spring (10) shown in Figure 15, first of all the“C” bush (14) having shock absorbing material is placed inside the cylindrical“C” bearing fixed shackle (15), and the screws (15.1 ) are inserted through the holes (15.2) located on the cylindrical“C” bearing shackle and are screwed to the screw holes (14.3) on the“C” bush having shock absorbing material. As a result the bush (14) is fixed inside the fixed shackle (15). After this fixation the composite leaf spring cylindrical hinge (12) with friction damage reducing“C” eye protector is mounted inside the bush as shown in Figure-7 by moving it at a cylindrical axis. (7.5) (The bush (14) can be used without the cylindrical hinge being mounted thereon, if desired).

If the composite leaf spring cylindrical hinge (13) with“C” eye protector having friction damage reducer and shock absorbing features in Figure 16, is to be mounted on the cylindrical“C” bearing fixed shackle, there is no need for the“C” bush (14) having shock absorbing material to be mounted as described in Figure 15. The shock absorbing material on the eye (13) is provided by the“C” shaped friction damage reducing eye protector (11.2) with shock absorbing material that is mounted during the production stage.

A composite cylindrical hinge leaf spring (10) can be attached to the“C” bearing leaf spring shackle (17) located on the leaf spring shackle cylindrical“C” bearing (17.1 ) shown in Figure 17, instead of the leaf spring shackle eye part (2.4.1 ) similar to the leaf spring shackle (2.4) mentioned in the known state of the art. (The“C” bush (14) having shock absorbing features that are used when attaching the cylindrical hinge composite leaf spring (10) to the cylindrical“C” bearing fixed shackle (15) can be similarly mounted and fixed to the cylindrical“C” bearing fixed shackle (15). All of the bearing mounting techniques, described for the fixed shackle (15) is similar for the cylindrical“C” bearing leaf spring shackle (17)). The fixed (15) and mobile (17) shackles for the leaf springs which have a single eye or which have an old type eye, can be used separately or together. As described in the known state of the art according to Figures 19 and 20; (the position taken by the leaf spring (2.5) shown in Figure-4 and Figure 5) when the vehicle is travelling on the road, if the wheel (2.3) encounters a pit, the cylindrical“C” bearing leaf spring shackle (17) rotates around the back mounting point hinge screw (3.4) at a clockwise direction during the downward movement (4.1 ) of the wheel and therefore the cylindrical composite leaf spring (10) is contracted and it takes the form shown in figure- 19. Although the composite front cylindrical hinge eye (19.1 ) having fiber fabric wound thereon, inside the cylindrical “C” bearing fixed shackle (12) can rotate in clockwise direction around a cylindrical axis (7.5), the back cylindrical hinge eye (19.2) with fiber fabric wound around it inside the leaf spring cylindrical“C” bearing (17.1 ) can rotate in an anti clockwise direction around the cylindrical axis (7.5) relative to the leaf spring shackle “C” bearing (17.1 ).

In figure 20, when the vehicle is travelling on the road, if the wheel (2.3) encounters a bump on the road, the cylindrical“C” bearing leaf spring shackle (17) rotates around the back mounting point hinge screw (3.4) at an anti-clockwise direction during the upward movement (5.1) of the wheel and therefore the leaf spring (10) is stretched and it takes the form shown in figure 20. Although the composite front cylindrical hinge eye (19.1 ) having fiber fabric wound thereon, inside the cylindrical“C” bearing fixed shackle (12) can rotate in an anti clockwise direction around a cylindrical axis (7.5), the back cylindrical hinge eye (19.2) with fiber fabric wound around it inside the leaf spring cylindrical“C” bearing (17.1 ) can rotate in a clockwise direction around the cylindrical axis (7.5) relative to the leaf spring shackle“C” bearing (17.1 ). Therefore the cylindrical hinge composite leaf spring (10) has completely met the leaf spring operation logic described in the known state of the art.