DESC:FIELD OF INVENTION

The present invention relates to a device for assembling automotive components requiring high torque for tightening thereof. In particular, the present invention relates to a flexible nut holder for tightening of bolts during assembly of automotive components to the vehicles. More particularly, the present invention relates to a flexible nut holder which also acts as a reaction bar to arrest the reaction moment produced during such tightening of the bolt through the nut.

BACKGROUND OF THE INVENTION

In automotive industry, there are many parts which require high (more than 80 Nm) torque for tightening of bolts while assembling these parts to the vehicles. Thus, the reaction bars are essential to arrest the moments produced during tightening of the bolts of these parts. However, it is not always possible to provide reaction bars, because only a few parts are required to be assembled in critical locations where there is be no feasibility to fix the other end of a reaction bar. Therefore, a reaction bar attached the tool is quite necessary for assembling such parts.

These reaction bars are normally long casted parts used for arresting the moments produced during tightening of bolts through the corresponding nuts, which involves a high (greater than 40 Nm) torque. The reaction bars are either temporarily or permanently attached to the Torque Control Nut Runners (TCNRs). The reaction bars consist of two ends, the first end fixed to the tool and the second end fixed to a structure other than the tool for transmitting the moment to the structure (Figure 1).

PRIOR ART

US 8490517 B2 discloses a hold and drive device for driving a nut on a bolt. It uses a motorized socket drive tool having an open drive socket located in a drive head portion. A support assembly having a spring loaded biasing portion configured for travel along a torque arrest path, where a torque arrest member is coupled with the spring loaded biasing portion in an operative position, is provided in a coupled arrangement with the motorized socket drive tool. The open drive socket is directed to pass over the nut and the torque arrest member is directed to engage the bolt such that the open drive socket may drive the target nut, while the torque arrest member holds the bolt from rotation. The open drive socket and torque arrest member are respectively released from the nut and the bolt after the nut reaches a predetermined destination on the bolt.

US 4688454 A discloses an open-ended, high torque wrench for use on a nut of selected size to which there is limited access. It comprises a single jaw seven-point open-ended wrench having a double square socket attached to one opposite ends spaced by an opening from the other opposite end. The jaw is dynamically stiffened and has a substantial jaw support. Where the arc of the jaw ends, there are flat surfaces to receive opposite flat sides of a six-point nut or the nut may be received by moving the wrench in the direction of the axis of the nut to thereby engage it. The drive socket is positioned at 900 from the jaw opening.

However, the above prior art documents do not disclose a device, e.g. nut holder which is neither very effective to arrest the reaction moments produced during the assembly of automotive components like nut-bolts on vehicles, nor which facilitates holding such nuts during tightening of the corresponding bolts by using high torque. As there is no feasibility to provide external reaction bar due to accessibility and safety issues, there is a requirement of a reaction bar which is attached to the TCNR used for tightening of bolts. Therefore, there is a need to design a flexible nut holder, which acts as a very effective tool to arrest the moments produced on assembling such parts. It is also needed to hold the nut while tightening for eliminating Non-value-added activities.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:
An object of the present invention is to provide a device for arresting the moments produced during assembly of the fasteners requiring high torque for tightening the same to the vehicle.

An object of the present invention is to provide a flexible nut holder which also acts as a reaction bar to enhance safety during tightening of components.

Still another object of the present invention is to provide a flexible nut holder which eliminates non-value-added activity like holding the nut with spanner.

A yet another object of the present invention is to provide a flexible nut holder which reduces the operator’s fatigue.

A further object of the present invention is to provide a flexible nut holder which provides a safer working environment to the operator.

A still further object of the present invention is to provide a flexible nut holder which is simple in construction and cost-effective to manufacture and use.

A yet further object of the present invention is to provide a flexible nut holder which is easily accessible by the operator and easy to use.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

DESCRIPTION OF THE INVENTION

A conventional reaction bar directly transmits the torque generated during bolt tightening to a fixed structure, which in turn produces reaction moments according to Law of Equilibrium.
Accordingly, whenever a force or torque is applied on a fixed bar, an equivalent and opposite force or torque is applied on the bar from the structure to which it is fixed. This reaction moment nullifies the torque produced, so the operator doesn’t experience any moment.

The flexible nut holder configured in accordance with the present invention works on the principle of Laws of equilibrium. Unlike the conventional devices therefor, this flexible nut holder receives the reaction moment from the nut, which in turn receives the reaction moment from the vehicle (fixed structure).

As against the conventional reaction bar, the reaction moment is transmitted to the Torque Control Nut Runner (TCNR) in two stages for the purpose of arresting the torque as well as for securely holding the nut during tightening of the bolt therein. For example, while tightening the mounting bolts of the lower control arm of the vehicle involving a high torque value (about 80 Nm), this flexible nut holder arrests the moments produced thereby. Simultaneously, this flexible nut holder also acts as a reaction bar and attachable to TCNR used for bolt tightening on vehicle structures.

SUMMARY OF INVENTION

In accordance with an embodiment of the present invention, there is provided a flexible nut holder attachable to torque controlled nut runners, the nut holder used to tighten bolts in nuts for assembly of automotive component.

Typically, the nut holder arrests high torque or reactive moments produced during tightening of bolts in nuts for assembly of automotive component such as lower control arm (LCA) on a vehicle structure.

Typically, the nut holder comprises:

• a bar extension with a support for tool and for contacting the surface of a vehicle structure during bolt tightening;

• a nut holding bar with a slider thereon for transmitting reaction torque produced in the nut;

• a nut holding socket for holding the nut in position during tightening thereof;

• a spring for compensating tolerances in vehicle bracket on which an automotive component is to be tightened;

• a bolt holding socket for holding the bolt during nut tightening;

• a bolt holding bar for transmitting the reaction torque from the vehicle structure to the tool;

• a U-clamp for clamping the nut holder to the tool;

• a slender bar for connecting the nut holding bar and bolt holding bar to transmit reaction force from the vehicle structure to tool; and

• a socket holder to firmly hold the bolt head socket to provide it additional support.

Typically, the bar extension comprises an octagonal support for tool and to contact the surface of a vehicle structure during bolt tightening.

Typically, the nut holding bar comprises a slider configured thereon for transmitting the reaction torque produced in the nut to the slender bar.

Typically, the spring is configured as an extendible/retractable spring for compensating the tolerances in the vehicle bracket for tightening an automotive component, such as lower control arm (LCA) thereon.

Typically, the U-clamp facilitates the clamping or assembly of the nut holder to the tool as well as an easy dismantling of the nut holder from the tool.

Typically, the bolt holding bar transmits the reaction torque from the slender bar to the tool to nullify the torque produced on operator’s hand during bolt tightening in the nut.
In another embodiment of the present invention, there is also provided a flexible nut holder comprising:

• a bar extension with an octagonal support for tool and to contact the surface of a vehicle structure during bolt tightening;

• a nut holding bar with a slider configured thereon for transmitting the reaction torque produced in the nut to the slender bar;

• a nut holding socket for holding the nut in position during tightening thereof;

• the spring configured as an extendible/retractable spring for compensating the tolerances in the vehicle bracket for tightening an automotive component, such as lower control arm (LCA) thereon;

• the bolt holding socket for holding the bolt during nut tightening;

• the bolt holding bar for transmitting the reaction torque from the slender bar to the tool to nullify the torque produced on operator’s hand during bolt tightening in the nut;

• the U-clamp configured to facilitate the clamping or assembly of the nut holder to the tool and for easy dismantling thereof from the tool;

• a slender bar for connecting the nut holding bar and bolt holding bar to transmit reaction force from the vehicle structure to tool; and

• a socket holder to firmly hold the bolt head socket to provide additional support thereto.

In accordance with the present invention, there is also provided a method of tightening the bolts in nuts for assembly of automotive component on a vehicle structure by means of a flexible nut holder, wherein the method comprises the steps of:
(a) placing the bolt holding socket on the bolt head to be tightened by pressing the support of the bar extension against the vehicle structure;

(b) placing the nut holding socket on the nut for holding it in position and elongating the spring;

(c) operating/actuating a Torque Controlled Nut Runner (TCNR) by filling compressed air therein for rotating the bolt holding socket at a predetermined speed;

(d) pulling forward the bolt holding bar by means of the slender bar on passage of the bolt through the nut;

(e) absorbing the reaction moment produced from the vehicle structure at the end of the bolt travel by means of the nut holding bar to be transmitted further to the slender bar; and

(f) transmitting the reaction moment received by the slender bar to the bolt holding bar for controlling the reaction moment produced from the TCNR during bolt tightening in the nut.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings.

Figure 1 shows a typical arrangement of a conventional torque control nut runner (TCNR) by means of a reaction bar for tightening a fastener in a vehicle structure.

Figure 2 shows a schematic diagram of the torque produced due to the force applied for tightening a fastener in an automotive structure.

Figure 3 shows a perspective view of the flexible nut holder configured in accordance with the present invention.

Figure 4 shows an enlarged perspective view of the front portion of the flexible nut holder of Figure 3.
Figure 5 shows a side view of the flexible nut holder of Figure 3, with the front portion A thereof encircled therein to be subsequently described in more detail.

Figure 6a shows an enlarged view of portion A of the flexible nut holder of Figure 5.

Figure 6b shows the front-view of the flexible nut holder of Figure 6a.

Figure 6c shows the top-view of portion A of the flexible nut holder of Figure 6a.

Figure 7a shows the stages involved in the transmission of the reaction moment in the conventional reaction bar of Figure 1.

Figure 7b shows the stages involved in the transmission of the reaction moment in the flexible nut holder made according to the present invention as shown in Fig. 3.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the flexible nut holder configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a typical arrangement of a conventional double-ended reaction bar with its one end fixed to the bolt-tightening tool and the other end fixed to the vehicle structure other than the said tool for transmitting the reaction moment to the said vehicle structure. Normally, it involves a torque control nut runner (TCNR) 10 for tightening a fastener 14 (e.g. bolt) in a nut fixed on the vehicle structure 16 by means of a reaction bar 18, which includes a first end (temporarily or permanently) attached to the vehicle structure 16. The operator holds the reaction bar 18 by using left-hand grip LHG provided thereon and tightens the bolt in the nut fixed on vehicle structure 16 by using right-hand grip RHG provided on TCNR 18.

Figure 2 shows a schematic diagram of the torque produced due to the force applied for tightening a fastener in an automotive structure. Here, the torque T is applied in a clockwise direction and an equal resisting torque T is produced in the anticlockwise direction. The corresponding planes of applied shear and complimentary shear opposing the same are also depicted in this figure.

Figure 3 shows a perspective view of the flexible nut holder 100 configured in accordance with the present invention. It includes a bar extension 102 with an octagonal support to provide additional support to the tool. It comes in contact with the surface of the vehicle structure during tightening of the fastener, e.g. bolt. Due to this surface contact, the friction between the surface of the structure and the tool provides additional supporting force. A nut holding bar 104 with a slider is used for transmitting the reaction torque T produced in the nut 114 to the slender bar 116 and travels along with the bolt though the shank length thereof. A nut holding socket 106 is used for holding the nut while tightening the bolt therein. Its pitch circle diameter (PCD) is slightly higher than that of the nut to ensure proper holding force (clearance fit). A spring 108 provides the flexibility to the nut holder 100 for compensating the tolerances in the bracket of the vehicle on which the component is to be mounted. A bolt holding socket 110 is used for holding the bolt during tightening thereof. Its PCD is slightly higher than the bolt head to ensure a proper holding force (with a suitable clearance fit). A bolt holding bar 112 is used for transmitting the reaction torque T from the slender bar 116 to the tool/hand to nullify the torque generated during tightening. A U-clamp 114 is used to clamp flexible nut holder 100 to the tool. It facilitates in assembling and dismantling flexible nut holder 100 whenever required. A slender bar 116 connects the nut holding bar 114 and the bolt holding bar 112 to transmit the reaction force from the vehicle structure to the tool. A socket holder 118 is used to firmly hold the socket of the bolt head and to provide additional support to the socket.

Figure 4 shows an enlarged perspective view of the front portion of the flexible nut holder of Fig.3 depicting the parts thereof already described above.

Figure 5 shows a side view of the flexible nut holder 100 of Fig.3, with the front portion A thereof encircled therein to be subsequently described in more detail.

Figure 6a shows an enlarged view of portion A of the flexible nut holder 100 of Fig.5.

Figure 6b shows the front-view of the flexible nut holder of Fig.6a.

Figure 6c shows the top-view of portion A of the flexible nut holder of Fig.6a.

Figure 7a shows the stages involved in the transmission of the reaction moment in the conventional reaction bar of Fig.1, which are transmitted from the structure 16 to the tool 10.

Figure 7b shows the stages involved in the transmission of the reaction moment in the flexible nut holder made according to the present invention as shown in Fig. 3, which are transmitted from the structure 116 to the tool 100 via the nut 114.

DESCRIPTION OF THE INVENTION

A conventional reaction bar transmits the torque generated during the tightening of the bolt directly to a fixed structure, which in turn produces reaction moment according to above Law of Equilibrium. This reaction moment nullifies the torque produced, so the operator doesn’t feel any moment.

The flexible nut holder configured in accordance with the present invention works on the principle of Law of Equilibrium, which states that whenever a force or torque is applied on a fixed bar, an equivalent and opposite force or torque is applied on the bar from the structure to which it is fixed. This flexible nut holder receives the reaction moment from the nut, which in turn receives the reaction moment from the vehicle (fixed structure). Therefore, the reaction moment is transmitted here to Torque Control Nut Runner (TCNR) in two stages. This serves the purpose of both arresting the torque and holding the nut during tightening of the bolt simultaneously.
This is a unique feature of the flexible nut holder as compared to the conventional reaction bars. The flexible nut holder 100 arrests the moments produced during tightening the mounting bolts of Lower Control Arm (LCA) to the vehicle, which involves a high torque value (80 Nm).

Further, due to friction between the threads of the bolt and the nut, the nut is in a static condition with respect to the bolt, because of which the bolt will not get through the nut completely. This required an additional activity of holding the nut with the help of spanner to eliminate static condition of nut on the bolt. This additional activity can also be eliminated with the help of flexible nut holder. In particular, the bolts of the lower control arm of the vehicle involve high torque value (80 Nm) for tightening of bolts of the same.

Flexible nut holder configured according to the present invention is an effective tool useful for arresting the high torque generated during tightening of bolts of a part to be assembled to the vehicle. It is used wherever there is a necessity for the reaction bar, but it is not feasible due to technical and accessibility issues. For example, the Lower control arm (LCA) fitment contains four bolts to be mounted for its assembly to the vehicle. Initially, the operator mounts the LCA to the vehicle and pre-tightens the bolts manually with finger spins. Subsequently, the operator holds TCNR equipped with the flexible nut holder 100 and a reaction bar.

WORKING OF THE INVENTION

The operator first places the bolt holding socket 110 on the bolt head. While placing the socket 110, the octagonal support 102 is pressed against the vehicle’s surface for additional support during bolt tightening. Then, the nut holding socket 106 is placed on the nut for holding it in position. The spring 108 is extended while placing the nut holding socket 106 on the nut. On actuation of the TCNR by the operator on pressing the button, the compressed air (pressure = 6 bar) enters the TCNR and the socket starts rotating with specified speed.
As the bolt passes though the nut, the bolt holding bar 112 travels forward with the help of slender bar 116. The socket holder 118 provides additional support to the socket during tightening. At the end of the travel, the nut holding bar 104 absorbs the reaction moment T generated from the structure and transmits it to the slender bar 116, which in turn transmits this reaction moment T to the bolt holding bar 112, thus controls the reaction torque T generated from the TCNR during tightening. The bolt holding bar 112 further transmits the reaction moment T to the tool to nullify the torque T generated.

The flexible nut holder can be used for all TCNRs and can be easily assemble and dissembled whenever required with the help of U clamp (7).

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The flexible nut holder configured in accordance with the present invention has the following technical and economic advantages:

• Nullifies the torque transmitted on the operator’s hand by the reaction torque transmitted through the nut holder (reaction bar).

• Eliminates an unsafe condition.

• Converts the ergonomic status of the tightening activity from RED to GREEN.

• Eliminates the non-value-adding activity of holding the nut using the spanner, which reduces 4.5 minutes of skilled work for each vehicle.

• Eliminates the need for two skilled personnel, which leads to a cost-saving of the order of INR 5.8 lakhs/annum.

• In-house design of the nut holder, which is fabricated as part of the low-cost automation initiative, leading to CAPEX savings of about INR 8 lakhs.

• It is to be understood that the present invention is not limited in its application to the details of the construction and to the arrangements of the components as mentioned in the above description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, the terminologies used herein are for the purpose of description and should not be regarded as limiting.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Therefore, while the embodiments herein have been described in terms of preferred embodiments, the skilled person will recognize that the embodiments herein can be practiced with modification within the spirit and scope of embodiments described herein.

The skilled person can easily make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies, assemblies and in terms of the size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. ,CLAIMS:We claim:

1. A flexible nut holder (100) attachable to torque controlled nut runners, said nut holder used to tighten bolts in nuts for assembly of automotive component.

2. Flexible nut holder (100) as claimed in claim 1, wherein said nut holder (100) arrests high torque or reactive moments produced during tightening of bolts in nuts for assembly of automotive component such as lower control arm (LCA) on a vehicle structure.

3. Flexible nut holder (100) as claimed in claim 1, wherein said nut holder (100) comprises:

• a bar extension (102) with a support for tool and for contacting the surface of a vehicle structure during bolt tightening;

• a nut holding bar (104) with a slider thereon for transmitting reaction torque produced in the nut;

• a nut holding socket (106) for holding the nut in position during tightening thereof;

• a spring (108) for compensating tolerances in vehicle bracket on which an automotive component is to be tightened;

• a bolt holding socket (110) for holding the bolt during nut tightening;

• a bolt holding bar (112) for transmitting the reaction torque from the vehicle structure to the tool;

• a U-clamp (114) for clamping said nut holder to the tool;

• a slender bar (116) for connecting said nut holding bar (104) and bolt holding bar (112) to transmit reaction force from said vehicle structure to tool; and

• a socket holder (118) to firmly hold the bolt head socket to provide additional support thereto.
4. A flexible nut holder (100) as claimed in claim 3, wherein said bar extension (102) comprises an octagonal support for tool and to contact the surface of a vehicle structure during bolt tightening.

5. A flexible nut holder (100) as claimed in claim 3, wherein said nut holding bar (104) comprises a slider configured thereon for transmitting the reaction torque produced in the nut to said slender bar (116).

6. A flexible nut holder (100) as claimed in claim 3, wherein said spring (108) is configured as an extendible/retractable spring for compensating the tolerances in the vehicle bracket for tightening an automotive component, such as lower control arm (LCA) thereon.

7. A flexible nut holder (100) as claimed in claim 3, wherein said U-clamp (114) facilitates the clamping or assembly of said nut holder to the tool as well as an easy dismantling of said nut holder from said tool.

8. A flexible nut holder (100) as claimed in claim 3, wherein said bolt holding bar (112) transmits the reaction torque from said slender bar (116) to the tool to nullify the torque produced on operator’s hand during bolt tightening in said nut.

9. Flexible nut holder (100) as claimed in claim 1, wherein said nut holder comprises:

• a bar extension (102) with an octagonal support for tool and to contact the surface of a vehicle structure during bolt tightening;

• a nut holding bar (104) with a slider configured thereon for transmitting the reaction torque produced in the nut to said slender bar (116);

• a nut holding socket (106) for holding the nut in position during tightening thereof;

• said spring (108) configured as an extendible/retractable spring for compensating the tolerances in the vehicle bracket for tightening an automotive component, such as lower control arm (LCA) thereon;

• said bolt holding socket (110) for holding the bolt during nut tightening;

• said bolt holding bar (112) for transmitting the reaction torque from said slender bar (116) to the tool to nullify the torque produced on operator’s hand during bolt tightening in said nut;

• said U-clamp (114) configured to facilitate the clamping or assembly of said nut holder (100) to the tool and for easy dismantling thereof from the tool;

• a slender bar (116) for connecting said nut holding bar (104) and bolt holding bar (112) to transmit reaction force from said vehicle structure to tool; and

• a socket holder (118) to firmly hold the bolt head socket to provide additional support thereto.

10. A method of tightening the bolts in nuts for assembly of automotive component on a vehicle structure by means of a flexible nut holder as claimed in claims 1 to 9, wherein said method comprises the steps of:

(a) placing the bolt holding socket (110) on the bolt head to be tightened by pressing the support of said bar extension (102) against said vehicle structure;

(b) placing said nut holding socket (106) on said nut for holding it in position and elongating said spring (108);

(c) operating/actuating a Torque Controlled Nut Runner (TCNR) by filling compressed air therein for rotating said bolt holding socket (3) at a predetermined speed;

(d) pulling forward said bolt holding bar (112) by means of said slender bar (116) on passage of said bolt through said nut;

(e) absorbing the reaction moment produced from said vehicle structure at the end of said bolt travel by means of said nut holding bar (104) to be transmitted further to said slender bar (116); and

(f) transmitting said reaction moment received by said slender bar (116) to said bolt holding bar (112) for controlling said reaction moment produced from said TCNR during bolt tightening in said nut.

Digitally Signed.

Dated: this 27th day of February 2018. (SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT