DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A TOOL HOLDER FOR A TORQUE MULTIPLIER ASSEMBLY

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present invention claims priority from Indian patent application numbered IN 202141027429 filed on 18th June, 2021.

TECHNICAL FIELD OF THE INVENTION

[002] The present invention relates to a tool holder for a torque multiplier assembly for torquing the hardware and more particularly it relates to a tool holder to hold and restrict the movement of torque multiplier while performing the torquing operation in under slung position.

BACKGROUND OF THE INVENTION
[003] In 3-Phase Mainline Electric Multiple Unit (MEMU) cars, the major equipment’s like Main Transformer, Main Compressor, Electro Pneumatic (EP) unit, Battery Box etc. are installed in under slung position on the underframe of the body shell structure with the help of applicable hardware. Dampening plates are commonly used for mounting of main transform. The installation of these dampening plates is carried out by providing high torque to the dampening plate mounting bolts, using a torque multiplier assembly. It is very difficult for a person to hold the heavy torque multiplier along with torque wrench against the gravity during tightening of the mounting bolts in an under slung position on the underframe of the body shell structure. The torque multiplier multiplies the torque using a torque wrench for tightening the bolts.
[004] Figure 1 illustrates a transformer assembly (10) mounted in an under slung position on the underframe (11) of the body shell structure. A dampening plate (13) is mounted at the bottom surface of the underframe (11) with the help of plurality of bolt assemblies (14) is bolted to the underframe (11) through the dampening plate (13). The bolt assembly (14) for the mounting of the dampening plate (13) comprises a bolt, a conical spring washer, a plain washer and a nut. The nut of the bolt assembly (14) is held above the underframe (11) and then the bolt is inserted from below into the holes provided in the underframe (11) and dampening plate (13) and then tightened. To achieve desired high torque for tightening the dampening plate mounting bolts, the torque multiplier is used to tighten the bolt assembly (14).
[005] Figure 2 illustrates the components of torque multiplier assembly. The torque multiplier assembly comprises a torque multiplier (20), a torque wrench (25) and a hexagonal head socket (26). The torque multiplier (20) has a first end (21) to be connected to the torque wrench (25) and a second end (22) to be connected to the hexagonal head socket (26). Further, the torque multiplier (20) comprises of a reaction arm (23) extending radially outwards from the outer surface of the torque multiplier (20). In order to tighten the dampening plate mounting bolt assembly (14), hexagonal head socket (26) is placed below the head of the mounting bolt assembly (14) which is driven by the torque multiplier (20) through the torque wrench (25).
[006] However, while tightening the dampening plate mounting bolt assembly using the torque multiplier, due to high torque requirement, the torque multiplier tend to rotate together with torque wrench resulting in not achieving the desired high torque for tightening the bolt. There is a need to develop a tool to hold and restrict the rotation of torque multiplier while carrying out torquing operation safely and by reducing the delays, saving cost and improving productivity.

OBJECTS OF THE INVENTION
[007] The object of the invention is to provide a tool holder for holding a torque multiplier assembly while tightening the bolt on the underframe of the body shell structure in an under slung position.
[008] Another object of the invention is to provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier, thereby achieving required high torque for tightening the dampening plate mounting bolt assemblies.
[009] Yet another object of the invention is to provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier while tightening the dampening plate mounting bolt assemblies, to reduce the reaction force at the torque wrench, thereby increasing safety.
[0010] Yet another object of the invention is to provide a tool holder for a torque multiplier assembly to hold the torque multiplier while performing the torquing operation in under slung position, to keep the torque multiplier in engaged position with the bolt head by supporting the weight of the torque multiplier assembly in turn increasing the safety and efficiency of the operator, and reducing the effort for tightening the bolts.
[0011] Yet another object of the invention is to provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier, to enhance the productivity and reduce the cost associated with the dampening plate mounting operation.

SUMMARY OF THE INVENTION
[0012] Before the present system is described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosure. It is also to be understood that the terminologies used in the description is for the purpose of describing the particular version or embodiment only and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to a tool holder for a torque multiplier assembly and the aspects are further elaborated below in the detailed application description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0013] In one implementation a tool holder for a torque multiplier assembly comprises a hollow cylindrical tool body to position a torque multiplier and a pair of opposing fingers attached to upper end of the hollow cylindrical tool body. The fingers extend in the direction of axis of the hollow cylindrical tool body and away from the hollow cylindrical tool body. A rectangular through hole is cut near the free end of each finger. A longitudinal slot is provided starting from the upper end of the hollow cylindrical tool body and extending axially to a partial length of the hallow cylindrical tool body to position a reaction arm of the torque multiplier. Two T-plates are provided in such a way that the stem of the T-plate is insertable in the rectangular through holes of the tool holder. Further, two locating pins are used to align the dampening plate holes to the holes provided on the underframe. The tool holder, in addition to restricting the rotational movement of the torque multiplier, also supports the weight of the torque multiplier assembly.
[0014] In another implementation, a method for tightening the dampening plate mounting bolt assembly with the help of a tool holder according to present invention is provided. First the dampening plate is properly aligned with the help of locating pins on the underframe and fixed on the underframe with the help of plurality of bolt assemblies. The torque multiplier is positioned in the hallow cylindrical tool body of the tool holder in such a way that the reaction arm of the torque multiplier is positioned in the longitudinal slot of the tool holder to restrict the rotational movement of the torque multiplier during tightening. Then, a torque wrench is connected to the first end of the torque multiplier and the hexagonal head socket is connected to the second end of the torque multiplier. Now, the torque multiplier assembly together with the tool holder is positioned below the dampening plate in such a manner that the head of the bolt is positioned in the hexagonal head socket. Further, the torque multiplier assembly together with the tool holder is locked with respect to the underframe in under slung position by inserting two T-plates in each of the rectangular holes provided in the fingers of the tool holder and by partially inserting the stems of the T-plates in the gap above the channel in the underframe. After securing torque multiplier and tool holder along with torque wrench to the underframe, ensure that a releasing pin at the first end of the torque multiplier is in closed position, then the torque wrench is rotated till the set torque value is achieved. As the rotational movement of the torque multiplier is restricted, required high torque is achieved with improved productivity and safety. Then, the torque multiplier assembly together with the tool holder is removed by flipping the releasing pin to open position to unwind the torque multiplier and then the T-plates are removed from the rectangular through holes. The same procedure is followed for tightening all the dampening plate mounting bolts.

STATEMENT OF INVENTION
[0015] The present subject matter discloses a tool holder for a torque multiplier comprising a hollow cylindrical tool body, plurality of fingers and a longitudinal slot. One end of the finger is mounted on an upper end of the hollow cylindrical tool body and another end is a free end provided with a through hole. The longitudinal slot is configured on the hollow cylindrical tool body for arresting the position of torque multiplier. The longitudinal slot is configured from the upper end of the hollow cylindrical tool body to a predetermined length of the hollow cylindrical tool body. The through hole is configured to receive a stem of a T-plate to securely lock the tool holder on an underframe of a body shell structure. The size of the finger is configured to vary based on variation in the size of the underframe. The fingers are configured to extend in the direction of axis of the hollow cylindrical tool body. The hollow cylindrical tool body is configured to secure the torque multiplier. The longitudinal slot is configured to secure a reaction arm of the torque multiplier to restrict rotational motion. The tool holder is configured to support the torque multiplier during operation.
[0016] The present invention further discloses a method of tightening a bolt assembly by using a torque multiplier and a tool holder. The method comprises steps of aligning a dampening plate at a desired position on an underframe with the help of locating pins, securing the dampening plate on the underframe using the bolt assemblies, positioning the torque multiplier in the tool holder wherein the reaction arm of the torque multiplier is positioned in the longitudinal slot provided on the hollow cylindrical tool body, connecting a hexagonal head socket to the second end of the torque multiplier, lifting and positioning the torque multiplier together with the tool holder, under the dampening plate, wherein the head of the dampening plate mounting bolt assembly is received in the hexagonal head socket of the torque multiplier, locking the tool holder on the underframe in under slung position by inserting T-plate into the rectangular slots provided on the tool holder, mounting a torque wrench to the first end of the torque multiplier and holding a nut of the bolt assembly above the underframe with the help of a spanner, mounting a torque wrench to the first end of the torque multiplier and holding a nut of the bolt assembly above the underframe with the help of a spanner, maintaining a releasing pin of the tool multiplier in closed position, tightening the dampening plate mounting bolt assembly by the torque wrench connected to the torque multiplier till the desired torque value is achieved. Further, the releasing pin is flipped to open position to release the torque multiplier and T-plates are removed to unmount the torque multiplier together with the tool holder.

BRIEF DESCRIPTION OF DRAWINGS
[0017] The foregoing summary, as well as the following detailed description of embodiment, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, however, the disclosure is not limited to the specific method and apparatus disclosed in the document and the drawings.
[0018] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0019] Figure 1 illustrates a transformer assembly (10) mounted in an under slung position on the underframe (11) of the body shell structure (Prior art);
[0020] Figure 2 illustrates components of a torque multiplier assembly, i.e., a torque multiplier (20), a torque wrench (25) and a hexagonal head socket (26) (Prior art);
[0021] Figure 3 illustrates an isometric view of a tool holder (300) for a torque multiplier assembly, in accordance to the present disclosure;
[0022] Figure 4 illustrates front, top and side views of a tool holder for a torque multiplier assembly, in accordance to the present disclosure;
[0023] Figure 5 illustrates an isometric, front, top and side views of a T-plate (500), in accordance to the present disclosure;
[0024] Figure 6 illustrates an isometric, front and top views of a locating pin (600), in accordance to the present disclosure;
[0025] Figure 7 illustrates a torque multiplier assembly with a tool holder positioned and locked on the underframe for tightening the dampening plate mounting bolt assembly in under slung position, in accordance to the present disclosure; and
[0026] Figure 8 illustrates a flowchart (800) of a method of tightening the dampening plate mounting bolt assembly, in accordance to the present disclosure.
[0027] Figure depicts various embodiments of the present disclosure for purpose of illustration only. Only skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words “comprising”, “having”, and “including,” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, tool holder for torque multiplier assembly are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0029] Various modification to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to another embodiment. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
[0030] The disclosure herein provides a tool holder for a torque multiplier assembly to be used for tightening the dampening plate mounting bolt assemblies. Figure 3 illustrates the isometric view and Figure 4 illustrates the front, top and side views of the tool holder (300). The tool holder (300) comprises a hollow cylindrical tool body (301) to position the torque multiplier (20) and a pair of opposing fingers (302) attached to upper end of the hollow cylindrical tool body (301). The fingers (302) extend in the direction of axis of the hollow cylindrical tool body (301) and away from the hollow cylindrical tool body (301). A rectangular through hole (303) is cut near the free end of each finger (302) to receive a T-plate (500). A longitudinal slot (304) is provided starting from the upper end of the hollow cylindrical tool body (301) and extending axially to a partial length of the hollow cylindrical tool body (301) to position the reaction arm (23) of the torque multiplier.
[0031] Figure 5 illustrates isometric, front, top and side views of the T-plate (500) having a stem (501) and a head (502). The dimensions of T-plate are such that the stem (501) of the T-plate (500) is able to insert in the rectangular through hole (303) of the tool holder (300) and the head (502) of the T-plate (500) restricts further insertion of the T-plate (500) in the rectangular through hole (303).
[0032] Figure 6 illustrates an isometric, front and top views of a locating pin (600). The dampening plate (13) is properly aligned on the underframe (11) by inserting the locating pins (600) into the holes provided in the underframe (11) and the dampening plate (13).
[0033] Figure 7 shows the torque multiplier assembly with the tool holder (300) positioned and locked on the underframe (11) for tightening the dampening plate bolt assemblies (14). As shown in figure 7, the bolt head of the bolt assembly (14) is received in the hexagonal head socket (26) that is connected to second end (22) of the torque multiplier (20) and the torque multiplier assembly is supported in the tool holder (300) in accordance with present disclosure. The tool holder (300) is locked on the underframe (11) to restrict the rotational movement of the torque multiplier assembly by inserting T-plates (500) in the rectangular through holes (303). In addition to restricting the rotational movement of the torque multiplier (20), the tool holder (300) along with T-plates (500) supports the entire weight of the torque multiplier (20) and the hexagonal head socket (26) in turn increasing the safety of the operator and reducing the reaction and the effort required at the torque wrench (25).
[0034] Figure 8 shows a flowchart of the method (800) of tightening the dampening plate mounting bolt assembly (14) in accordance with present invention. At 801, the dampening plate (13) is aligned at desired position on the underframe (11) with the help of locating pins (600) and then the dampening plate (13) is fixed on the underframe (11) using the bolt assemblies (14). At 802, the torque multiplier (20) is positioned in the tool holder (300) in such a way that the reaction arm (23) of the torque multiplier (20) is positioned in the longitudinal slot (304) provided on the hollow cylindrical tool body (301). The hexagonal head socket (26) is connected to the second end (22) of the torque multiplier (20). At 803, the torque multiplier assembly together with the tool holder (300) is lifted and positioned under the dampening plate (13) in such a way that the head of the dampening plate mounting bolt assembly (14) is received in the hexagonal head socket (26) of the torque multiplier assembly. At 804, the tool holder (300) is locked on the underframe (11) in under slung position by inserting T-plate (500) in each rectangular through hole (303) of the tool holder (300) and by partially receiving the stem (501) of the T-plate (500) in the gap above the channel in the underframe (11). At 805, the torque wrench (25) is connected to the first end (21) of the torque multiplier (20) and a nut of the bolt assembly (14) is held above the underframe (11) with the help of a spanner. A releasing pin (27) (shown in figure 7) is provided on the first end (21) of the torque multiplier (20) and kept in closed position while tightening the bolt. At 806, the dampening plate mounting bolt assembly is tightened by the torque wrench (25) connected to the torque multiplier (20) till the desired torque value is achieved. At 807, the releasing pin (27) (shown in figure 7) is flipped to open position to release the torque multiplier (20), then the T-plates (500) are removed to remove the whole torque multiplier assembly together with the tool holder (300). Same procedure is repeated for tightening all dampening plate mounting bolt assemblies.
[0035] As per one embodiment, the torque wrench (25) has a torque range of 55 Nm to 200 Nm and the torque multiplier has a multiplication factor of 12. So, the torque that can be achieved using the given torque wrench at the hexagonal head socket (26) is in the range of 660 Nm to 2400 Nm. However, the given range can be varied based on the size and torque rating of the torque wrench (25) and the torque multiplier (20). Moreover, the spanner used for holding the nut of the dampening plate bolt assembly (14) can be either a single ended spanner or a double ended spanner. However, any other provision can be used to hold the nut of the dampening plate bolt assembly (14) above the channel of the underframe (11) and aligning with the hole provided in the underframe while tightening the bolt of the dampening plate bolt assembly (14) by the torque multiplier assembly in accordance with present disclosure.
[0036] Accordingly, present invention discloses a tool holder (300) for a torque multiplier (20) comprising a hollow cylindrical tool body (301), plurality of fingers (302) and a longitudinal slot (304). One end of the finger (302) is mounted on an upper end of the hollow cylindrical tool body (301) and another end is a free end provided with a through hole (303). The longitudinal slot (304) is configured on the hollow cylindrical tool body (301) for arresting the position of torque multiplier (20). The longitudinal slot (304) is configured from the upper end of the hollow cylindrical tool body (301) to a predetermined length of the hollow cylindrical tool body (301). The through hole (303) is configured to receive a stem (501) of a T-plate (500) to securely lock the tool holder (300) on an underframe (11) of a body shell structure. The size of the finger (302) is configured to vary based on variation in the size of the underframe (11). The fingers (302) are configured to extend in the direction of axis of the hollow cylindrical tool body (301). the fingers (302) are configured to extend in the direction of axis of the hollow cylindrical tool body (301). The hollow cylindrical tool body (301) is configured to secure the torque multiplier (20). The longitudinal slot (304) is configured to secure a reaction arm (23) of the torque multiplier (20) to restrict rotational motion. The tool holder (300) is configured to support the torque multiplier (20) during operation.
[0037] The present invention further discloses a method of tightening a bolt assembly (14) by using a torque multiplier (20) and a tool holder (300). The method comprises following steps:
1. aligning a dampening plate (13) at a desired position on an underframe (11) with the help of locating pins (600),
2. securing the dampening plate (13) on the underframe (11) using the bolt assemblies (14),
3. positioning the torque multiplier (20) in the tool holder (300) wherein the reaction arm (23) of the torque multiplier (20) is positioned in the longitudinal slot (304) provided on the hollow cylindrical tool body (301),
4. connecting a hexagonal head socket (26) to the second end (22) of the torque multiplier (20),
5. lifting and positioning the torque multiplier (20) together with the tool holder (300), under the dampening plate (13), wherein the head of the dampening plate mounting bolt assembly (14) is received in the hexagonal head socket (26) of the torque multiplier (20),
6. locking the tool holder (300) on the underframe (11) in under slung position by inserting T-plate (500) in each through hole (303) of the tool holder (300),
7. mounting a torque wrench (25) to the first end (21) of the torque multiplier (20) and holding a nut of the bolt assembly (14) above the underframe (11) with the help of a spanner,
8. maintaining a releasing pin (27) of the tool multiplier (20) in closed position,
9. tightening the dampening plate mounting bolt assembly by the torque wrench (25) connected to the torque multiplier (20) till the desired torque value is achieved.
[0038] Further, the releasing pin (27) available on the torque multiplier (20) is flipped to open position to release the torque multiplier (20) and T-plates (500) are removed to unmount the torque multiplier (20) together with the tool holder (300).
[0039] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following:
[0040] Some embodiments of the present subject matter provide a tool holder for holding a torque multiplier assembly while tightening the bolt on the underframe of the body shell structure in an under slung position.
[0041] Some embodiments of the present subject matter provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier, thereby achieving required high torque for tightening the dampening plate mounting bolt assemblies.
[0042] Some embodiments of the present subject matter provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier while tightening the dampening plate mounting bolt assemblies, to reduce the reaction force at the torque wrench, thereby increasing safety.
[0043] Some embodiments of the present subject matter provide a tool holder for a torque multiplier assembly to hold the torque multiplier while performing the torquing operation in under slung position, to keep the torque multiplier in engaged position with the bolt head by supporting the weight of the torque multiplier assembly in turn increasing the safety and efficiency of the operator, and reducing the effort for tightening the bolts.
[0044] Some embodiments of the present subject matter provide a tool holder for a torque multiplier assembly to hold and restrict the movement of torque multiplier, to enhance the productivity and reduce the cost associated with the dampening plate mounting operation
[0045] Although implementations for a tool holder for a torque multiplier and method of tightening a bolt assembly by using a torque multiplier and a tool holder, have been described in language specific to structural features and/or system, it is to be understood that the appended claims are not necessarily limited to the specific features described. Rather, the specific features are disclosed as examples of implementations.
[0046] Below is a list of elements with reference numerals which may be used for implementation of the present subject matter.
Reference Numerals Element name
10 A transformer assembly
11 Underframe
12 A mounting bracket
13 A dampening plate
14 Bolt assemblies
20 A torque multiplier
21 First end
22 Second end
23 A reaction arm
25 Torque wrench
26 Hexagonal head socket
27 Releasing pin
300 A tool holder
301 A hollow cylindrical tool body
302 A pair of opposing fingers
303 A rectangular through hole
304 A longitudinal slot
500 T-plate
501 Stem of T-plate
502 Head of T-plate
600 A locating pin
,CLAIMS:

1. A tool holder (300) for a torque multiplier (20) comprising:
a hollow cylindrical tool body (301);
plurality of fingers (302), wherein one end of the finger (302) is mounted on an upper end of the hollow cylindrical tool body (301) and another end is a free end provided with a through hole (303); and
a longitudinal slot (304) configured on the hollow cylindrical tool body (301) for arresting the position of torque multiplier (20).

2. The tool holder (300) as claimed in claim 1, wherein the longitudinal slot (304) is configured from the upper end of the hollow cylindrical tool body (301) to a predetermined length of the hollow cylindrical tool body (301).

3. The tool holder (300) as claimed in claim 1, wherein the through hole (303) is configured to receive a stem (501) of a T-plate (500) to securely lock the tool holder (300) on an underframe (11) of a body shell structure.

4. The tool holder (300) as claimed in claim 3, wherein the size of the finger (302) is configured to vary based on variation in the size of the underframe (11).

5. The tool holder (300) as claimed in claim 1, wherein the fingers (302) are configured to extend in the direction of axis of the hollow cylindrical tool body (301).

6. The tool holder (300) as claimed in claim 1, wherein the hollow cylindrical tool body (301) is configured to secure the torque multiplier (20).

7. The tool holder (300) as claimed in claim 6, wherein the longitudinal slot (304) is configured to secure a reaction arm (23) of the torque multiplier (20) to restrict rotational motion.

8. The tool holder (300) as claimed in claim 1, wherein the tool holder (300) is configured to support the torque multiplier (20) during operation.

9. A method of tightening a bolt assembly (14) by using a torque multiplier (20) and a tool holder (300), comprises steps of:
aligning a dampening plate (13) at a desired position on an underframe (11) with the help of locating pins (600);
engaging the dampening plate (13) on the underframe (11) using the bolt assemblies (14);
positioning the torque multiplier (20) in the tool holder (300) wherein the reaction arm (23) of the torque multiplier (20) is positioned in the longitudinal slot (304) provided on the hollow cylindrical tool body (301);
connecting a hexagonal head socket (26) to the second end (22) of the torque multiplier (20);
lifting and positioning the torque multiplier (20) together with the tool holder (300), under the dampening plate (13), wherein the head of the dampening plate mounting bolt assembly (14) is received in the hexagonal head socket (26) of the torque multiplier (20);
locking the tool holder (300) on the underframe (11) in under slung position by inserting T-plate (500) in each through hole (303) of the tool holder (300);
mounting a torque wrench (25) to the first end (21) of the torque multiplier (20) and holding a nut of the bolt assembly (14) above the underframe (11) with the help of a spanner;
maintaining a releasing pin (27) of the torque multiplier (20) in closed position; and
tightening the dampening plate mounting bolt assembly by the torque wrench (25) connected to the torque multiplier (20) till the desired torque value is achieved.

10. A method of tightening a bolt assembly as claimed in claim 8, wherein the releasing pin (27) is flipped to open position to release the torque multiplier (20) and T-plates (500) are removed to unmount the torque multiplier (20) together with the tool holder (300).