[001] The present application is a patent of addition of parent application 201911030339 dated July 26, 2019 and titled “THREADLESS NYLOC NUT” which was granted on February 25, 2020 with Patent Number “332905”. A PCT application was also filed with application number PCT/IN2019/050674.

TECHNICAL FIELD

[002] The subject matter in general relates to a fastening device, for example, nut-bolt. More particularly, but not exclusively, the subject matter relates to a Semi-threaded Nyloc Nut with an insert made up of a polyamide material with combination of threaded metal part and threadless insert.

BACKGROUND

[003] Background description includes information that may be useful in understanding the present subject matter.

[004] Mechanical fasteners play a vital role in our day to day life. They are used in a variety of applications, right from holding together a piece of furniture that we use, to the hi-tech automobile that we use to travel long distances. Mechanical fasteners are broadly divided into permanent and non-permanent fasteners. Threaded bolts and nuts are one such type of non-permanent mechanical fasteners. [005] Conventionally used plain nut and bolt require little torque to tighten the plain nut on the bolt. The little torque used means that the nut will loosen easily with the application of external load such as vibrations. To overcome such problems, Nyloc nuts were developed, where a small washer made of a polyamide material is used within the threaded nut. These require significantly more torque to tighten and accordingly more torque to loosen than a conventional plainnut. However, even the Nyloc nuts do not provide the required tightening and loosening torque. [006] Also, in a given nut bolt arrangement, the length of the nut has no real effect on the torque. That is, altering the length of the nut will not vary the torque of the given nut bolt arrangement. Thus, different set of nut and bolt are to be used to meet the required torque, thereby changing the weight dynamics of the device the fastener is being used in. This plays an important role in an industry, such as aerospace, where the weight of the airplane is an important factor. Reduction in weight amounts to large savings in the operating costs.

[007] There are two main types of bolted joints designs; tension joints and shear joints. [008] In the tension joint, the bolt and clamped components of the joint are designed to transfer an applied tension load through the joint by way of the clamped components by the design of a proper balance of joint and bolt stiffness. Much of the torque applied is lost overcoming friction at the bolt head or nut under torque (50%) and in the threads (40%). The remaining 10% of the applied torque does useful work in stretching the bolt and providing the preload.

[009] The second type of bolted joint transfers the applied load in shear of the bolt shank and relies on the shear strength of the bolt. In such shear joints preload is only incidental as these are designed to allow rotation of the joint about the bolt, but use other methods of maintaining bolt- joint integrity, and rely on a locking mechanism like in nyloc nuts; commonly also called lock nuts. Locking mechanisms keep bolted joints from coming loose.

[0010] Referring to FIGs. 1A and IB, a conventional Nyloc nut (henceforth called conventional nut) 100 with a nylon insert 102 is illustrated, in accordance with an embodiment. The conventional nut 100 with internal threads, for example, but not limiting to, an M14 X 2 nut is shown in FIG. 1A.

[0011] FIG IB is a section view of the conventional nut 100 along X-X axis (shown in FIG. 1A). A nylon insert 102 is affixed towards face end 104 of the conventional nut 100, such that a continuous threaded bore 106 is defined by the conventional nut 100. Having such threaded nuts have multiple drawbacks which were discussed in the background section.

[0012] The conventional nuts are completely threaded to receive threaded outer portion of the bolt and also have an insert. [0013] However, this existing combination of nut and bolt in the conventional nuts has several technical disadvantages in view of torque and cost.

OBJECTS OF THE DISCLOSURE

[0014] In view of the foregoing limitations inherent in the state of the art, some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.

[0015] It is an object of the present disclosure to propose a Semi-threaded Nyloc Nut with combination of internal partly threaded metal portion and internal threadless polyamide insert (henceforth called insert).

[0016] It is yet another object of the present disclosure to propose a Semi- threaded Nyloc Nut with increased tightening and loosening torque.

[0017] It is still yet another object of the present disclosure to propose a Semi-threaded Nyloc Nut, wherein the length of engagement of the Semi-threaded Nyloc Nut can be altered to meet varied tightening and loosening torque requirements. [0018] It is still yet another object of the present disclosure to propose a

Semi-threaded Nyloc Nut, wherein the bore comprises a threaded metal portion and a threadless insert.

[0019] It is still yet another object of the present disclosure to propose a Semi-threaded Nyloc Nut, wherein the height of the threaded portion and the threadless-insert may be varied as per requirements. [0020] It is still yet another object of the present disclosure-to further provide an improvement in Indian Patent Number 332905 in the form of a technical feasibility empowering in providing the preload as in tension joints along with the increased tightening and loosening torque as in shear joints as already claimed in Indian Patent Number 332905.

[0021] It is still yet another object of the present disclosure to provide an opportunity of a trade-off between the preload and the prevailing torque, and thus possibly making a joint better for both types of applications.

[0022] It is still another object of the present disclosure to provide the designers of the nut an opportunity to design a joint to meet their unique requirements of preload and prevailing torque simultaneously that are presently not available.

[0023] These and other objects and advantages of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present invention is illustrated.

SUMMARY

[0024] This summary is provided to introduce concepts related to a Semi- threaded Nyloc Nut. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0025] The present disclosure relates to a Semi-threaded Nyloc Nut configured to receive a male threaded member. The Semi-threaded Nyloc Nut comprises a nut body and an insert. The nut body defines a multi-step through hole comprising a threaded bore and a first bore. The threaded bore and the first bore converge to define a first spigot. The insert is configured to be received by the first bore. The insert defines a through hole to receive a threaded member. First end of the insert rests on the first spigot to arrest axial movement of the insert with respect to the nut body.

[0026] Other objects, features and advantages of the present disclosure will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0027] While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as forming the present subject matter, it is believed that the present disclosure will be better understood from the following description taken in conjunction with the accompanying drawings, where like reference numerals designate like structural and other elements, in which:

[0028] FIG. lAis a top view of a conventional nut 100;

[0029] FIG. IB is a section view of the conventional nut 100 along X-X axis;

[0030] FIG. 2 is a section view of a Threadless Nyloc Nut 200 of parent application;

[0031] FIG. 3 is a section view of a nut body 202 of the Threadless Nyloc Nut 200 of parent application;

[0032] FIG. 4 is a section view of an insert 204 of the Threadless Nyloc Nut 200 of parent application; [0033] FIG. 5 discloses a Semi-threaded Nyloc Nut 1300, in accordance with an embodiment; [0034] FIG. 6 discloses a body 1306 of Semi-threaded Nyloc Nut 1300 in accordance with an embodiment;

[0035] FIG. 7 discloses an insert 1304of Semi-threaded Nyloc Nut 1300 in accordance with an embodiment; [0036] Fig. 8 discloses a graph of test result of test 1, in accordance with an embodiment;

[0037] Fig. 9 discloses a graph of test result of test 2, in accordance with an embodiment;

[0038] Fig. 10 discloses a graph of test result of test 3, in accordance with an embodiment;

[0039] Fig. 11 discloses a graph of test result of test 4, in accordance with an embodiment; and

[0040] Fig. 12 discloses a graph of test result of test 5, in accordance with an embodiment. DETAILED DESCRIPTION

[0041] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0042] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes”, “consisting” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.

[0044] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0046] Referring to FIGs.2, 3 and 4, a Threadless Nyloc Nut 200 of the parent application is illustrated, in accordance with an embodiment. The Threadless Nyloc Nut 200 may comprise a nut body 202 and an insert 204.

[0047] In an embodiment, the insert 204 may define a through hole 406 to allow the passage of a threaded member (not shown), such as a threaded bolt. The insert 204 may be made up of a polyamide material with high resilience properties. As an example, but not limited to, the insert 204 may be made up of nylon 6 or nylon 66.

[0048] In an embodiment, the insert 204 may be independently fabricated using conventional moulding techniques.

[0049] In an embodiment, the nut body 202 may define a multi-step through hole 302. The multi-step through hole 302 may comprise a first bore 304, a second bore 306 and a third bore 308. The first bore 304 and the second bore 306 may converge to define a first spigot 310, and the first bore 304 and the third bore 308 may converge to define a second spigot 312.

[0050] In an embodiment, the insert 204 may be received by the first bore 304 with first end 402 of the insert 204 resting on the first spigot310.The first spigot 310arrests the axial movement of the insert 204 with respect to the nut body 202. [0051] In an embodiment, the insert 204 may comprise a head portion 404.

The head portion 404 may be received by the third bore 308 and may rest on the second spigot 312.

[0052] In an embodiment, the insert 204 may be press fitted into the nut body 202 as per the above described configuration. [0053] In an embodiment, face 314 of the nut body 202 may be bent inward to form a lip 206, wherein the lip 206 may engage with the head portion 404 of the insert 204. The lip 206 may be crimped at several points. This prevents the axial and rotational movement of the insert 204 with respect to the nut body 202.

[0054] In an embodiment, the second bore 306 of the nut body 202 may be chamfered for easy entry of the threaded member into the Threadless Nyloc Nut

200. [0055] In an embodiment, tightening and loosening torque of the Threadless Nyloc Nut 200 may be increased or decreased by varying the length of the first bore 304. That is, if the length of the first bore 304 is increased, the tightening and loosening torque increases and if the length of the first bore 304 is decreased, the tightening and loosening torque decreases. Varying the length of the first bore 304 means varying the length of the insert 204.

[0056] The above described configuration of the Threadless Nyloc Nut 200 may be employed to the whole range of commercially available nuts, including the generally available nuts M14 and M12 as discussed in parent patent application.

[0057] In view of the foregoing Threadless Nyloc Nut 200, the present disclosure provides a Semi-threaded Nyloc Nut 1300 that provides the preload as in tension joints along with the increased tightening and loosening torque as in shear joints as claimed in the Threadless Nyloc Nut 200 of the parent application. [0058] Improvement in reference to present subject matter for which protection is sought

[0059] Referring to FIG. 5, disclosed is a Semi-threaded Nyloc Nut 1300, in accordance with an embodiment, which is an improvement over the Threadless Nyloc Nut 200. The Semi-threaded Nyloc Nut 1300 may comprise a nut body 1306, a partly threaded metal 1302 and a threadless insert 1304 which is made of polyamide material. The nut body 1306 is made of metal having multi-step through hole with variable diameter.

[0060] FIG. 6 discloses the Semi-threaded Nyloc Nut body 1306 in accordance with an embodiment. The nut body 1306 may define a multi-step through hole 1416 to allow the passage of the threaded member (not shown), such as a threaded bolt. The multi-step through hole 1416 is used to produce Semi- threaded Nyloc Nut body 1306 that has threads in the metal, and receives the threadless insert 1304. [0061] In an embodiment, the multi-step through hole 1416 may comprise a threaded bore 1402, a first bore 1404 and a second bore 1406. The threaded bore 1402 and the first bore 1404 may converge to define a first spigot 1410, and the first bore 1404 and the second bore 1406 may converge to define a second spigot 1412.

[0062] In an embodiment, the threaded bore 1402 is made in the metal of nut body 1306 and is made to mate the threaded bolt.

[0063] In an embodiment, the nut body 1306 may comprise a lip 1414, wherein the lip 1414 that may be configured to be bent inward towards the multi- step through hole 1416 on the threadless insert 1304 and crimped on the threadless insert 1304.The crimped lip 1414 on the threadless insert 1304 ensures no axial movement of the nylon part during insertion of bolt and making of threads by the bolt on the threadless insert 1304. Also this part is pressed atleast at 4-6 points on the circumference to ensure no rotational movement of the threadless insert 1304. This is just like in the Threadless Nyloc Nut of the parent application.

[0064] Referring to FIG. 7, disclosed is the threadless insert 1304, in accordance with an embodiment. The threadless insert 1304 may comprise a head portion 1504. In an embodiment, the threadless insert 1304 may be press fitted into the nut body 1306 in the first bore 1404 and the second bore 1406 as per the above described configuration.

[0065] In an embodiment, the threadless insert 1304 may define a through hole 1502 to allow the passage of the threaded member (not shown), such as a threaded bolt. The threadless insert 1304 may be made up of a polyamide material with high resilience properties. As an example, but not limited to, the threadless insert 1304 may be made up of nylon 6 or nylon 66.

[0066] In an embodiment, the threadless insert 1304 may be independently fabricated using conventional moulding techniques. [0067] In an embodiment, the threadless insert 1304 may be received by the first bore 1404 with a first end 1506 of the threadless insert 1304 resting on the first spigot 1410. The first spigot 1410 arrests the axial movement of the threadless insert 1304 with respect to the Semi-threaded Nyloc Nut body 1306. [0068] In an embodiment, the head portion 1504of the threadless insert 1304 may be received by the second bore 1406 and may rest on the second spigot 1412.

[0069] In an embodiment, the threadless insert 1304 may be press fitted into the nut body 1306as per the above described configuration.

[0070] In an embodiment, the lip 1414 of the nut body 1306 may be configured to be bent inward to engage with a second end 1508 of the threadless insert 1304 when the threadless insert 1304 is inserted into the nut body 1306.

[0071] In an embodiment, the lip 1414 may be crimped at several points thereby arresting axial movement and rotational movement of the threadless insert 1304 with respect to the nut body 1306. [0072] In an embodiment, tightening and loosening torque of the Semi- threaded Nyloc Nut 1300 may be increased or decreased by varying the length of the first bore 1404. That is, if the length of the first bore 1404 is increased, the tightening and loosening torque increases and if the length of the first bore 1404 is decreased, the tightening and loosening torque decreases. Varying the length of the first bore 1404 means varying the length of the threadless insert 1304.

[0073] In an embodiment, inner diameter ‘d’ of the threadless insert 1304is less than major diameter ‘D’ of the Semi -threaded Nyloc Nut 1300.

[0074] The above described configuration of the Semi-threaded Nyloc Nut

1300 may be employed to the whole range of commercially available nuts, including, for example, the generally available nuts M14 and M12 in the Metric system, and ½” UNC in Inch system. [0075] In an embodiment, the height of the threaded bore 1402 may be represented by the height “h” and the height of the first bore 1404 along with the height of the threaded bore 1402 may be represented by the height “H”, which is also the normal engagement length of a standard bolt and nyloc nut configuration of a given size. Thus, the height of the first bore 1404 is equal to “H-h”.

[0076] In an embodiment, the heights “H” and “h” may be varied as per requirements. The height “h”may be varied to suit the desired design outcomes of the Semi-threaded Nyloc Nut 1300 bolt combination.

[0077] As an exemplary embodiment, for M14 X 1.5 Semi-Threadless Nyloc Nut, the height “h” may be 6mm, whereas the height “H” may be 12mm.

[0078] In an embodiment, when the requirement is that of a fully threaded nyloc nut, the height “h” is made equal to the height “H”.

[0079] In an embodiment, whenthe requirement is that of the Threadless Nyloc Nut 200, the height “h” is made equal to 0. [0080] Thus, the Semi-threaded Nyloc Nutl300 has the advantage over the conventional nuts to vary the height “h” anywhere from 0 to “H” to have a trade off between the preload and the prevailing torque, and thus possibly making a joint better for both types of applications. It also provides the designers an opportunity to design a joint to meet their unique requirements of preload and prevailing torque simultaneously that are presently not available.

EXPERIMENTAL TEST RESULTS

[0081] To better understand the usefulness of the disclosed Semi-threaded Nyloc Nut, tests were conducted on a chosen ½ “UNC bolt and Semi-threaded Nyloc Nut combination. In the parent invention metric sizes were used. Here, purposely inch size has been chosen to provide better insight to the users of inch system. All dimensions are given first in inches with equivalent numbers in mm given in the brackets. For forming threads in the metal part, the hole ID was kept at 0.423” (10.75mm), the nylon insert ID was kept at 0.451” (11.45mm). The total height H of the metal part was 0.315” (8mm). Five tests, as follows, were conducted varying h= height of the threaded metal part from 0.315” (8mm) to 0” (0mm) which also corresponds to H-h= height of the threadless nylon insert from 0” (0mm) to 0.315” (8mm). Each test was done for 10 cycles where one cycle is one complete tightening and one complete loosening. It was found that the tightening and loosening torque for ½ “UNC bolt with plain nut is less than 1 Nm.

[0082] Test#l (See Graph -1 as illustrated in fig. 8): h=0.315” (8mm) H-h=0” (0mm). This becomes a conventional nut. Results show that the tightening and loosening torques for the first cycle are 3.3 Nm and 6 Nm respectively.

[0083] Test#2 (See Graph -2 as illustrated in fig. 9): h=0.236” (6mm) H- h=0.079” (2mm). This represents a Semi-threaded Nyloc Nut. Results show that the tightening and loosening torques for the first cycle are 5.1 Nm and 9 Nm respectively. These are more than Test#l. [0084] Test#3 (See Graph -3 as illustrated in fig. 10): h=0.158” (4mm) H- h=0.158” (4mm). This also represents a Semi-threaded Nyloc Nut. Results show that the tightening and loosening torques for the first cycle are 11.1 Nm and 16 Nm respectively. These are more than Test#l.as well as Test#2

[0085] Test#4 (See Graph -4 as illustrated in Fig. 11): h=0.079” (2mm) IT- h=0.236” (6mm). This also represents a Semi-threaded Nyloc Nut. Results show that the tightening and loosening torques for the first cycle are 12.1 Nm and 16.7 Nm respectively. These are more than Test#l, Test#2 and Test#3.

[0086] Test#5 (See Graph -5 as illustrated in Fig. 12): h=0.0” (0mm) H- h=0.315” (8mm). This represents a Threadless Nyloc Nut as disclosed in parent patent. Results show that the tightening and loosening torques for the first cycle are 18.4 Nm and 21.2 Nm respectively. These are more than Test#l, Test#2, Test#3 and Test#4. [0087] Conclusions from the test results:

1. The tightening and loosening torques increase as the height of the nylon insert is increased. It means that designed tightening and loosening torques can be achieved by changing the height of the nylon insert.

2. The loosening torque is always more than the tightening torque. This is expected because of the resilience of the polyamide insert.

3. By making the height of the nylon insert zero, one can use it as a conventional nut.

4. By making the height of the nylon insert maximum, one can use it as a Threadless Nyloc Nut.

5. The values of tightening and loosening torques, as well as their dependence on the number of cycles, are in line with the reported results in the parent patent. This further reconfirms the validity and conclusions of the parent patent.

TECHNICAL ADVANTAGE

[0088] The present disclosure proposes a Semi-threaded Nyloc Nut with combination of partly threaded metal body and threadless nylon insert.

[0089] The present disclosure proposes a Semi-threaded Nyloc Nut with increased tightening and loosening torques when compared to the conventional nuts.

[0090] The present disclosure proposes a Semi-threaded Nyloc Nut wherein the length of the threadless insert can be altered to meet varied tightening and loosening torque requirements.

[0091] The present disclosure proposes a Semi-threaded Nyloc Nut wherein the height of the threaded portion and the mrt insert may be varied as per requirements.

[0092] Furthermore, each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0093] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be constmed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

[0094] Furthermore, those skilled in the art can appreciate that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.

[0095] While the foregoing describes various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the present disclosure is determined by the claims that follow. The present disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.