JP6416187B2 - Tension spring fitting with friction resistant coating - Google Patents

Description

  The present invention relates generally to mounts for springs, and more particularly to end-mounting tension springs and related friction resistant coatings.

  Nested springs are used in various applications. For example, it can be used for various devices for fixing fixtures to relatively moving parts and landing gears for aircraft. They are used where reliability is paramount to reduce the space envelope required where the spring is held. Examples of applications of the nested springs are throttle return springs, brake return springs, and valve springs.

  Often, nested springs have avoided a single failure by providing a redundant system. These replace single spring systems. With a single spring system, however, when a spring fails, all systems fail. Taking a double spring system increases the safety factor. If one spring fails, the other can function properly during the time it takes for the broken spring to be replaced. In some cases, where the springs are in contact with each other, the springs will be excessively bent, worn or twisted. In places where the contact is acute, such as a small contact surface area under high load conditions, the effect is exacerbated. Some materials are abrasives such as titanium, and wear faster than others.

  The present invention relates to an attachment for a spring. More specifically, the present invention couples a tension spring to the fixture in various applications that use spring tension and grooves to keep the fixture and spring together. Including an end-mount system. The system has an end fitting and an inner spring that are associated with an outer spring, the outer spring enveloping the inner spring, and an outer end mount being an inner end fitting. end mount) (resting on). These are fixed to the fixture on either end and can vary depending on the application.

  In accordance with a further embodiment of the present invention, the end fitting is cylindrical in shape to allow a helical tension spring to be wound onto a groove in the end fitting and secured to the end fitting. . In some embodiments, the end fitting groove has a pitch that is greater than the pitch of the tension spring prior to being secured to the fitting. In a preferred embodiment, the pitch of the mounting portion of the spring has a greater pitch than the remainder of the spring in order to match the pitch of the fixture groove. The inner diameter of the groove is slightly larger than the coil diameter of the spring. Similar to a Chinese finger trap, as the spring is tensioned, the increasing spring inward force holds the spring on the end fitting. When the spring becomes free from the end fitting, these forces tend to decrease the spring diameter throughout the spring.

  According to another embodiment of the present invention, the end fitting has a keyhole for fitting over end fixtures. The keyhole is shaped such that the end fitting fits over the fixture but does not cover the inner spring and the inner end fitting. The keyhole can have any shape as long as this purpose is satisfied.

  In accordance with a further embodiment of the invention, the fixture is attached or machined to the inner spring end fitting. These fixtures can be of various sizes and shapes based on at hand applications.

  In accordance with another aspect of the present invention, the dual spring system includes outer springs that encase the inner springs, allowing each spring to reduce mass and greatly increasing the strength of the system. In addition, a measure of safety is added for other springs introduced into the system. The resonant frequency of the combined spring system varies dramatically compared to a single spring system for the same application. This change in frequency can also be exploited in the safety of all systems by removing dangerous frequency coupling.

  As can be seen from the foregoing overview, the present invention adds a safety factor, is reliable in spring attachments without fasteners, and is safer and cleaner without mass. Provide attachments.

  Preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings.

FIG. 1 is a side view of a prior art arrangement of nested tension springs. FIG. 2 is a side view of a spring assembly. FIG. 3 is a side view of an inner portion spring assembly. FIG. 4 is a side view of an outer spring assembly. FIG. 5a is an isometric view of the outer spring end mount. FIG. 5b is an end view of the end fitting of the outer spring with a wider key-hole opening. FIG. 5c is a side view of the outer spring end fitting. FIG. 6 is a side view of an outer portion spring assembly. FIG. 7 is an isometric view of a machined channel and an end fitting with a friction resistant coating in the trench.

  As shown in FIG. 1, prior art nested tension springs 4 and 6 use an opposing hook to prevent the springs from being released from the position where they are held. To do. The outer hook 10 is mated with the inner hook 8. Previous tension springs 4 and 6 generally fail in hooks, most particularly in locations where large bending stresses on the hooks are faced with large torsional stresses transmitted from coils in a tensile load situation. Arise. The relationship of the hooks 8, 10 to the springs 4, 6 will be better understood from the following description. The operation of the springs 4 and 6 can be understood with reference to FIG. The embodiment comprises two tension springs 4, 6, an inner spring 4 and an outer spring 6. The springs 4 and 6 are connected by hooks 8 and 10 at both ends. The springs 4, 6 gather together so that the coiled spirals are wound in the opposite direction. The hooks 8 and 10 are, however, connected to the fixture in such a way that repeated hooking forces can cause the hook to break. These hooks 8, 10 do not have a clean or secure attachment. Stress concentrations occur in the component or fixture to which the hook is secured and the hook bend prior to the windings. Also, in the prior art, when a failure occurs in one spring, the hook moves, often causing a failure in all systems.

  In order to solve the above-described problems, an embodiment of the present invention is a fixture including end mounts 14 and 18 in such a manner that even if a tensile force is applied, a problem is unlikely to occur. Including an outer spring 16 and an inner spring 12 that connect to and a cleaner and secure attachment. These end fittings 14, 18 can be machined from a variety of materials such as metals, plastics or composites. The relationship of the end fittings 14, 18 to this embodiment will be better understood with reference to FIG.

  FIG. 2 shows a spring assembly 11 that includes an inner spring 12 to which fixtures 20, 21 with end fittings 14 are attached on either end. Surrounding the inner spring 12 is an outer spring 16 that is wrapped around the end fitting 18. Any component of the spring component 11 is applied to the outer surface to suppress friction and prevent twisting, bending, and other wear that occurs between the connections of the spring component 11. Coating 40 can be provided. The springs 12, 16, end fittings 14, 18, and any other component of the part 11 can have a coating 40. The coating 40 can be located between any two contacting surfaces. The coating 40 can be applied to one or both of the connection surfaces. For example, the coating 40 can be applied to the grooves of the end appendages 14, 18, or the springs 12, 16, or both the end appendages 14, 18 and the springs 12, 16. The coating 40 can be a nylon material such as nylon 11 or other suitable coating. The coating 40 can have any suitable thickness. In some embodiments, coating 40 is about 0.011 inch. The coating 40 can be applied to the outer surfaces of the springs 12, 16 using a powder coating application method. In some embodiments, the springs 12, 16 are made from a material such as 15-5 pH stainless steel or titanium. Some materials wear faster than others. In particular, titanium is an abrasive and can be worn by other contacting materials when exposed to sufficient stress. The coating 40 minimizes wear resulting from twisting, bending and other deformations as well as friction.

  The part 11 includes one or more springs, and the strength from multiple springs is combined so that each individual spring can have a lower mass. As a result of the lower mass of each individual spring in this system, the dual spring embodiment has a higher natural frequency. This higher natural frequency adds safety. This is because the frequency is outside the range of frequencies experienced during use. When a device experiences a frequency that is similar to its natural frequency, it will fail more easily. This has been confirmed with aircraft landing gear. Since the natural frequency of the system is higher, a measure of safety is added.

  Returning to the end fitting 18, the inner diameter of the groove 28 in the end fitting 18 is slightly larger than the resting coil diameter of the outer spring 16. Therefore, taking into account the fact that the spring described is a tension spring, the spring diameter tends to decrease naturally due to the tension applied to the spring. However, the end fitting 18 keeps the coil diameter the same on the end fitting 18. This crimps the outer spring 16 around the end fitting 18 and secures it securely without slipping. The coating 40 tensions the spring 16 so that when it contracts around the end fitting 18, the end fitting 18 and the spring 16 are particularly advantageous for the pressure created between these two members. Suppress wear during. Slip in the axial direction is suppressed by the end fitting 18, but the coating 40 is in a circular (circumferential) direction so that the spring 16 is tensioned. In contrast, the spring 16 is allowed to move somewhat. While the spring is being tensioned, a slight twist is applied to the spring. Some slight movement of the spring away from the end fitting occurs, particularly at the position where the spring exits the end fitting. The coating 40 applied to the end fitting groove in the position where the springs exit, provides a smooth, durable surface to resist wear on the springs and fittings.

  It is also noted that in some embodiments, the groove 28 in the end fitting 18 where the outer spring stays is spaced further apart than the natural pitch of the outer spring 16. I can do it. This creates an associated tension on the groove of the end fitting 18 as the outer spring 16 attempts to recoil to its free length. In the preferred embodiment, the ends of the springs are manufactured with a greater pitch to more closely match the pitch of the grooves 28. Such a spring makes it easier to fix the fixture. However, slipping can be avoided by a tighter grip of the tensioned spring, as described above.

  Another advantage for the embodiments provided by these end fittings 18 is that if one spring fails, the end fittings 14, 18 will have the same spring as the other. Holding in the same alignment. In the prior art, when one of the springs fails, the hooks 8 and 10 move. Such movement is particularly problematic in tight space envelopes or when the spring is close to a fuel tank or other combustible material where sparks can occur. The coating 40 further reduces friction, which can cause sparks, and further mitigates this risk. In addition, conventional fasteners are removed, further reducing the deficiencies. There are fewer places where defects occur. Bending stress is minimized and torsional stress spreads across multiple coils in an end-mounting region.

  Returning to the end fitting 18, there is a keyhole 24 provided, which is more particularly seen in FIG. The keyhole 24 extends through the wall 26 of the end fitting 18 so that the end fitting 18 can fit over the end fixtures 20 and 21 attached to the outer spring. . The keyhole 24 has a shape as shown on the wall 26 of the end fitting. The hole shape is formed to provide a clearance to fit over one end of the fixture, while the inner spring fitting or other stop as described below. Small enough to engage. The end fitting wall 26 is preferably a flat surface on which a snap ring 22 stays to hold the end fitting 18 in a position as shown in FIG. The coating 40 can be applied to any suitable area of the end fitting 18 or to all of the outer surfaces. In one embodiment, the external, grooved region that engages the spring 16 is applied, but the rest is not applied. Preferably, the last part of the groove adjacent to the springs on the end fitting, near the exit of the spring from the end mount Only the (final portion) is applied.

  Also, the end fitting 18 preferably has a recess that can be nested over the inner end fitting 14 and the inner spring 12. The inner surface 36 of the wall 26 at the end fitting 18 remains on the inner end fitting 14 or on the flange if a flange is used. Instead of a flange, a separate stop such as a washer can be used. The inner surface 36 can be coated as described above. The shape of the keyhole 24 may be specific to the fixture or may be a fixed shape such as a circle (as in FIG. 5a). The keyhole 24 allows the end fitting 18 to fit over the end fixtures 20 and 21 attached to the outer spring 16 so that the spring 16 can be wound on the end fitting 18. To do. The fasteners 20 and 21 attached to the outer spring 16 can vary in shape, size and length as required based on the desired application. Any part of the fixture 20, 21 can have a coating applied similar to that described above.

  Also, as mentioned in FIG. 5, the end fitting 18 has a taper 32 that turns into a groove 28 around which the outer spring 16 is wound. As described above, these grooves 28 can be spaced further apart than the natural resting pitch of the outer spring 16. The grooves 28 are constantly spaced and have a constant diameter. Since the spring is wound around the fixture, the force that rotates it tends to increase the diameter of the spring. However, once wound, the tension during use tends to hold the spring firmly. The groove 28 can have a coating 40 that is applied to aid in attachment by reducing friction between the end fitting 18 and the spring 16. The tapered coating 40 can be thicker and stiffer than the rest of the part 11 to further reduce twisting and bending and further reduce wear. In order to make more space between the spring and the fitting and the thicker coating fits more easily, the taper angle can be increased for applications requiring a thicker coating.

  The cylindrical side wall 30 of the end fitting 18 is preferably generally constant in diameter along its length. Of course, changes introduced by grooves outside the wall are excluded. The inner hole 34 may have a constant diameter that can fit over the inner end fitting 14 and shoulder 15 or 17 (shown in FIG. 3). However, the diameter of the inner bore 34 is preferably sufficient around the inner end fitting 14 and shoulder 15 or 17 so that it does not slide around and come out of place. tight. The bore surface 36 is preferably perpendicular and flat with respect to the side wall 30 of the end fitting 18. This allows the end fitting 18 to remain securely on the shoulder 15 or inner end fitting 14. The shoulder 15 can also be coated, similar to that described above, to reduce wear and to improve the nature of contact.

  As shown in FIG. 2, the outer spring end mount 18 remains on the inner spring end mount 14. The inner spring end fitting 14 has a flange 15 with a machined shoulder 17 or wall 19 that serves the purpose of holding the outer spring 16 in place, and the outer spring end attachment. A wall 19 is provided on which the tool 18 is secured. Any surface of the end fitting 14 can be coated with a coating similar to that described above for similar reasons. Having two springs 12 and 16 in the part results in additional spring strength being included, so that each spring can weigh less. The springs 12 and 16 are wound in opposite directions. The reason for this is linked to the fact that there are two tension springs 12 and 16, which adds great strength to the device. In certain embodiments, the inner spring 12 and the outer spring 16 may contact each other. Due to the coating 40 applied to the outer surface of the springs 12, 16, such contact does not adversely affect the performance of the part 11.

  Since the springs 12, 16 are wound in the opposite direction, when tension is applied to the springs 12, 16, they are pulled in different directions. Concomitantly, the use of two springs 12, 16 naturally adds a greater safety factor. As shown in FIG. 3, the device can also function with the use of only one spring. Fixtures 20 and 21 are still securely connected and the embodiment can function. Moreover, as shown in FIG. 4, even if a malfunction occurs in the inner spring 12, the outer spring 16 can still function. If one spring fails, the other one is still present and can function without the other. This device is particularly important because it is often used in applications with high loads and multi-directional, vibrating and / or high speed operation, which adds a measure of safety. It is.

  While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the scope and spirit of the invention. For example, a safety rod can be added for a higher level of safety. That is, if a failure occurs in the springs 12 and 16, the rod holds the fixture together. The rod can be attached from the rod into the fixture using a keyhole.

  Another example used in applications that secure outer end fitting 18 may use flanges. These flanges can replace the shoulders of the inner end fitting. The flange can be machined directly on the fixtures 20 and 21 or on the arms of the fixtures 20 and 21 depending on the application. These flanges can then hold the outer end fitting 18 in place.

  Also, depending on the fixtures 20 and 21, different sized outer end fittings 18 and keyholes can be used. Different sizes and materials can be used for springs 12 and 16 depending on strength requirements and device function. Free length, pitch, diameter, coil diameter, and number of coils can all vary. Similarly, depending on the coil diameter of the outer spring 16 and the size of the fixtures 20 and 21 to be attached, the diameter of the outer end fitting 18 can vary.

  FIG. 7 illustrates the end fitting 50 according to an embodiment of the present disclosure in which a coating 40 is applied to a predetermined surface of the end fitting 50. The end fitting 50 is generally similar to the other end fittings disclosed herein. Grooves of the end fitting 50 become the end 52. The final portion 54 of the grooves is machined to have a radius that is slightly larger than the remainder of the coils in order to accommodate the thickness of the coating 40. The The coating 40 can be applied to this final portion 54. When the spring is threaded on the end fitting 50, the coil exits the end 52. Thus, this final portion 54 encounters the majority of springs that rub and twist during use. The coating 40 helps reduce premature failure of the springs and appendages and friction. The dimensions of the final part 54 can vary for a given application based on how much the spring moves along the final part 54 during use. Wear caused by the connection of the spring end and the end fitting is suppressed.

  The dual spring system can alternatively be two or more springs, and can also be four or five springs. These do not necessarily have to be nested. These can fix one to the other adjacent, however this does not necessarily reduce the space envelope. Consequently, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the present invention should be fully defined by reference to the following claims.

  The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

Claims (2)

A tension spring retaining component for coupling between the first configuration and the second configuration to control movement between the first component and the second component mount assembly),
The part is
A first fixture formed for attachment to the first configuration, having an inner end portion having an abutment and an outer end portion formed for attachment to the first configuration A first fixture,
A second fixture formed for attachment to the second configuration, the second fixture having an inner end and an outer end for attachment to the second configuration;
A first tension spring coupled between the first and second fixtures, the first tension spring coupled to the first fixture and the second fixture; A first tension spring having a second end having
A first spring attachment for connecting the first end of the first tension spring to the inner end of the first fixture;
Any two of the first fixture, the first configuration, the support, the second fixture, the second configuration, the first tension spring, and the first spring fixture A friction resistant coating between and
The first spring fixture is a cylindrical groove (cylindrical) having a helical groove formed to receive the first tension spring and having a helical groove around which the first tension spring is wound. body)
The spiral groove has a pitch greater than the pitch of the first tension spring before being secured to the first spring fixture;
The first spring fixture is
A first end of the cylindrical body part;
A second end of the cylindrical body portion opposite the first end formed to receive the first tension spring;
And a friction-resistant coating formed at least on the last part of the second end,
The groove has a first radius corresponding to a diameter of the spring coil such that the spring coil of the first tension spring remains in the groove in a threaded manner. (Radius)
The groove at the final portion of the second end has a second radius greater than the first radius;
Said friction-resistant coating, a difference between tensile spring holding parts that have a substantially equal thickness between the first and the second radius. The first end of the cylindrical body has a keyhole;
The keyhole, the first walk through the outer end portion of the fixture (therethrough) is formed so as to allow the tensile spring holding part according to claim 1.