FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Offset Keyway Gauge
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR
Mahajan Prashant Magan, of Crompton Greaves Ltd, A-28 M5-Pumps Div. M1DC, Ahmednagar- 4141 11, Indian National.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to an offset keyway gauge.
BACKGROUND OF THE INVENTION
When two members are to be keyed together, it is a common practice to cut keyways in each of the members, which keyways are lined up to receive a key. However, the keyways in the two members do not line up and therefore have problems in engaging with each other and therefore rotating relative to each other.
In the prior art, the shaft center was not the same as the keyway center and the impeller center. At the time of the assembly, if the keyway was tapered, the pump assembly was required to be stopped and the motor was to be rejected for shaft keyway taper. One was required to find out the keyway taper, offset and the depth undersize before assembling, with the help of the micrometer. After taking multiple measurements, these dimensions were computed and thereafter it was certified as to whether the keyway
was satisfactory or not. This job was tedious, time consuming and not suitable for mass
i
production as each shaft could not checked. Further, these above operations were done before assembling on the complete motor. Therefore, the shaft used to be done away with, which was resulting into huge losses. The shaft could not be tested till the complete
assembly was put together with the motor. Therefore the time and the effort taken were
i
very high.

OBJECTIVES OF THE INVENTION
An objective of the invention is to provide an offset keyway gauge which obviates the aforesaid drawbacks by providing an offset keyway gauge using the dimensions of the keyway center and the impeller.
DETAILED DESCRIPTION OF THE INVENTION
In order to achieve the aforesaid and other objectives, according to the invention, a keyway offset gauge is designed. The keyway offset gauge comprises of a toroidal ring having a dovetail groove at its center, wherein the gauge is slidably engaged with a shaft for a keyway, such that the centre of the keyway is parallel to the center of the shaft and the center of the gauge. Further, the aforesaid centre of the keyway, center of the shaft and the center of the gauge are in one plane.
These and other aspects, features and advantages of the invention will be better understood with reference to the following detailed description, accompanying drawings and appended claims, in which,
Fig la illustrates the front view of the offset gauge. Fig lb illustrates a sectional view of the entire assembly.
Referring to the figures la and lb, the present invention relates to a keyway offset gauge (G) comprising of a toroidal ring (2) having a dovetail groove (3) at its center.

wherein the gauge (G) is slidably engaged with a shaft (S) for a keyway (K), such that the centre of the keyway (kc') is parallel to the center of the shaft (SGsc') and the center of the gauge (SGsc')- Further, the gauge and the shaft have a common center and C is perpendicular to center of shaft & gauge (SGsc'): Center of key Kc' & gauge groove center (gkc').
The gauge according to the invention is inserted into the shaft which has the key in the keyway. If the gauge passes through, then the same is available for use and it does not have any taper or offset. The gauge will pass through only when the center of keyway is parallel with the shaft center line and keyway center line are in the same plane. If gauge is stuck, then it signifies that the keyway has a taper or offset and it is not fine for use. Further, if the keyway depth is undersized, the gauge will not enter. If the shaft outer diameter is more, the gauge will not enter in the shaft.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternate embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the invention as defined.

We claim:
1. A keyway offset gauge comprising of a toroidal ring having a dovetail groove at its inside diameter, said gauge slidably engaged with a shaft for a keyway, such that the centre of said keyway is parallel to the center of said shaft and the center of said gauge.
2. A keyway offset gauge as claimed in Claim 1 wherein said centre of said keyway, center of said shaft and center of said gauge are in one plane.