FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION AN ATTACHMENT FOR POWER TOOL
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTOR
BADADHE SHAILESH P an Indian national
of TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in
which it is to be performed.

FIELD OF INVENTION
The present invention relates to a attachment which can be attached with a pneumatically or hydraulic power tool for tightening nut, and more particularly a bolt-nut tightening attachment which is conveniently usable for fasteners of one side type comprising a bolt and a nut which can be inserted & tightened up, respectively, at one side of members to be fastened together, where regularly used pneumatic nut runner with socket is difficult to insert due to scarcity of space availability for assembling nut and bolts.
BACKGROUND OF INVENTION
Power tools such as pneumatic or hydraulic with sockets are especially suited for use in assembly operations in the automotive and machine industries, so as to meet high standards of safety, quality, durability in assembly, also to increase the productivity. But in some assembly of parts it happen so that the socket with power tool is difficult to insert due to design restrictions and also design modification is not possible due to after sales component spares requires while repairs & servicing, needs to be replaced. All these reasons restrict use of power tools. In such case we have to use hand tools such as open head spanners, ratchets, & so on. Such tools application naturally reduces work efficiency & productivity. For example the propeller shaft assembly of heavy & medium commercial vehicles is manually done. The nuts are tightened at a specified torque at 3 places i. e.l) to gear box, 2) between two propeller shafts. 3) To the rear axle. Each assembly has 8 numbers of nuts and bolts, i. e. total 24 nos. Presently it is tightened manually as regular pneumatic nut runner fails to insert the socket to tighten the nut. Demerits: Time require is more, Increases manual work, Fatigue work.


SUMMARY OF THE INVENTION
To have a low cost automation for tightening bolts & nut, and more particularly to the bolt-nut tightening attachment fixed with power tool which is conveniently usable for fasteners of one side type comprising a bolt and a nut which can be inserted & tightened up, respectively, at one side of members to be fastened together.
An object of the invention is to provide a bolt-nut tightening arrangement free of the foregoing problem.
It is an object to provide an attachment for a rotary power tool which is not a member to give torque to nut to be tightened, but only an intermediate attachment between the power tool and the work, and which dose not has self power source. The present invention provides an attachment for power tools for tightening nut and bolt comprises two housings having a gear reduction mechanism accommodated therein and a handle projecting there from. A powered nut runner (which is a main drive source) rotational output is inputted to an inner socket of attachment which further rotates reduction gear mechanism and the main hexagonal spur gear is insert with a tip at the end of the nut.
Firstly set pneumatic or hydraulic powered nut runner to the torque required & in final direction of drive required i.e. in clockwise or anti- clockwise accordingly. Insert the hexagonal spur gear in the nut.
According to present invention an attachment for a power tool comprising a gear housing, a first drive shaft rotatable by said power tool, a first and second bevel gear, said first bevel gear connect to said drive shaft, said second bevel gear meshed with said first bevel gear there by rotatably driven by said first bevel gear, a second drive shaft rotatable by said second bevel gear, a first spur gear keyed to said second drive shaft, at least two spur gears rotatably driven by said first spur gear, at least


one of said spur gears having a opening therein to cooperate with a polygonal shaped fastening device.
Another embodiment of the invention provides an attachment for a power tool comprising a gear housing, a square bracket shaft rotatable by said power tool, a first and second spur gear, said first spur gear connected to said shaft, said second spur gear meshed with said first spur gear and rotatably driven by said first spur gear, said second spur gear having a opening therein to cooperate with a polygonal shaped fastening device, said square bracket shaft and said spur gears located in said gear housing, said gear housing having an opening to access said square bracket and said second spur gear rotatably mounted on opening at bottom of said gear housing.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows the cross sectional side view of the parallel axis drive attachment.
Fig. 2 shows the cross sectional front view of the parallel axis drive attachment
Fig. 3 shows the cross-section view of how parallel axis drive attachment is
functionally operated
Fig. 4 shows the top view of perpendicular axis drive attachment.
Fig. 5 shows the cross sectional side of the perpendicular axis drive attachment
Fig. 6 shows the cross sectional front view of the perpendicular axis drive attachment
Fig. 7 shows the cross-sectional view of how perpendicular axis drive attachment is
functionally operated.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.


Drive with attachment in combination with pneumatic nut runner can be achieved by two methods.
BY PARALLEL AXIS DRIVE METHOD
Attachment having parallel axis drive has a hexagonal spur gear meshed with intermediate spur gear, which is keyed to square socket shaft. Socket shaft is fitted with roller bearing. The drive transfer mechanism is assembled in two housing to have final parallel drive. A cap cover is fitted to on bearing on said housing.
Referring to Figure 1 & 2, different components of proposed attachment (10) for parallel axis drive mechanism are shown. The mechanism is having a square socket shaft (4) fitted with bearing (3). This bearing has a cap cover. On said square socket shaft step an intermediate spur gear (5) is keyed (7). This intermediate spur gear meshes with hexagonal spur gear (6) which finally gives torque to nut. Said hexagonal spur gear has flanges at both sides. These flanges are highly finished with close accuracy forming as a journal bearing with housing bore. This all component assembly forms a mechanism to have a drive to nut in parallel axis with the axis of power drive tool. This mechanism is fully coupled & mounted in housing (1).
Figure 2 shows the arrangement of attachment (10) with a power tool (40) to drive a nut (50), wherein the drive is transferred parallel to power tool axis. The power tool (40) is connected to the square socket shaft (4) and said square socket shaft keyed in first spur gear (5). The first spur gear is meshed with the second one (6) thereby transferring drive in parallel axis.
BY PERPENDICULAR AXIS DRIVE METHOD
Attachment having perpendicular axis drive has a hexagonal spur gear meshed with two intermediate spur gears to form a gear train. One of the spur gear has two


circlip for sidewise support. The other said spur gear is keyed on main shaft having two bearing support at both ends. Bevel gear is fitted on same shaft & the other bevel gear is keyed to square socket shaft. Socket shaft is fitted with roller bearing. The drive transfer mechanism is assembled in a housing to have final perpendicular drive. A cap cover is fitted for bearing on said housing.
It also has the advantages of less fatigue work, less manpower, less time, reduce production cost.
Referring to Figure 4, 5, & 6 different components of proposed attachment for perpendicular axis drive mechanism are shown. The mechanism is having a square socket shaft (20) fitted with roller bearing (15). This bearing has a cap cover (23) as shown. On the square socket shaft a bevel gear (13) is keyed which meshes with other bevel gear to transfer drive to the main shaft (16). This shaft rotates on roller bearing (14) at both ends as shown in fig 5. The spur gear (17) is keyed (22) on the main shaft (16) which transfer drive to intermediate spur gear (18). Said intermediate spur gear is fitted on a shaft with circlip (21) on both side. Said shaft is press fitted at one end in housing (11). This spur gear meshes with hexagonal spur gear/ end spur gear (19) which finally gives torque to nut. The opening in said spur gear (19) can be any polygonal shape to accommodate all kind of nuts. The hexagonal spur gear has flanges at both sides. These flanges are highly finished with close accuracy forming as a journal bearing with housing bore. This all component assembly forms a mechanism to have a drive to nut in perpendicular axis with the axis of power drive tool. The length of the drive train can be increased by adding spur gears which are meshed to each other at least one of them having opening therein to accommodate a polygonal shape fastening device. This mechanism is fully coupled & mounted in housing (11).
Referring to figure 7, a power tool (40) is connected to the square socket shaft of the attachment (30) to drive the nut arrangement (50). The power tool is placed perpendicular to the nut axis and the drive is transferred to the nut using two beveled


gears and two spur gears. The bevel and spur gears are located inside a housing which forms as an attachment so that it can be handled easily.
In both methods housing is fixed & mounted with power tool face. Square drive of power tool is inserted in socket of attachment to form a single unit. This housing has a handle for support and holds the system rigidly for easy operating. In some if the unit becomes heavy a balancer use is necessary as used regularly in production shops. It is easy to fix and man power required can be minimize with high safety operation.
The proposed attachment mechanism concept is universal in use to all size of nut , and as per drive application which depends on component assembly section design, size of bolt, torque etc.
Advantages
1. Low cost Automation.
2. Increases production & efficiency.
3. Reduce product cost,
4. Reduce manual fatigue work.


WE CLAIM
1. An attachment for a power tool comprising a gear housing, a first drive shaft rotatable by said power tool, a first and second bevel gear, said first bevel gear connect to said drive shaft, said second bevel gear meshed with said first bevel gear there by rotatably driven by said first bevel gear, a second drive shaft rotatable by said second bevel gear, a first spur gear keyed to said second drive shaft, at least two spur gears rotatably driven by said first spur gear, at least one of said spur gears having a opening therein to cooperate with a polygonal shaped fastening device.
2. An attachment for a power tool as claimed in claim 1 wherein said gear arrangement located in said gear housing.
3. An attachment for a power tool as claimed in claim 1 wherein said gear housing having an opening at first end inline with axis to access said first drive shaft.
4. An attachment for a power tool as claimed in claim 1 wherein said first drive shaft rotating on a roller bearing
5. An attachment for a power tool as claimed in claim 1 wherein second drive shaft support on roller bearing at two ends.
6. An attachment for a power tool as claimed in claim 1 wherein spur gears driven by said first spur gear includes an intermediate and end spur gears meshed together and said intermediate spur gear driven by said first spur gear.
7. An attachment for a power tool as claimed in claim l wherein said intermediate spur gear support on circlip at two ends.
8. An attachment for a power tool as claimed in claim l wherein said end spur gear having flanges and rotatably mounted on opening perpendicular to the axis of said gear housing located at the bottom.
9. An attachment for a power tool comprising a gear housing, a square bracket shaft rotatable by said power tool, a first and second spur gear, said first spur gear connected to said shaft, said second spur gear meshed with said first


spur gear and rotatably driven by said first spur gear, said second spur gear having a opening therein to cooperate with a polygonal shaped fastening device, said square bracket shaft and said spur gears located in said gear housing, said gear housing having an opening to access said square bracket and said second spur gear rotatably mounted on opening at bottom of said gear housing. 10. An attachment substantially as herein described with reference to accompanying drawings.