Title of Invention

A NOVEL DEEP GROOVE GRINDER

Abstract

A novel deep groove grinder for grinding in narrow gap formed between two thick section materials comprising a tool holding shaft (1), a shaft supporting housing (2), a clamp for housing (3) and an electric motor (4); characterized in that a tool holding shaft (1) being housed within said shaft supporting housing (2) which is held in position with the help of said clamp (3), said shaft supporting housing is provided with slotted end (5) in the upper portion, said slotted end is mounted on a motor and retained firmly in a predetermined position by said clamp, said shaft supporting housing (2) being supported by said electric motor (4) for operating said tool holding shaft for the grinder to work.

Full Text

Field and Background of the Invention The present invention relates to a novel deep grinder, more particularly a grinder which can operate within a narrow groove formed between two thick section materials. The invention relates to the development of a grinder, suitable for removing defects inside deep narrow grooves employed in submerged arc welding. In thick section material welding in order to improve the productivity several techniques are employed. Some of these techniques are use of tandem or multi wire technique, metal powder addition, long stick out welding etc. One of the important techniques of current interest is the use of narrower joint grooves. Conventional welding makes use of typical joint edge preparation as compared to this narrow gap welding employs near parallel sided edge preparation. The included angle for the joint will be in the range of 2 to 4 deg. The width of the joint at the root will be approximately 18-25 mm depending gpon the thickness of the material welded. This technique results in saving of up to 70% in weld metal requirement. In welding of critical components involving thick sections significant defects as per applicable codes are not permitted and hence they have to be removed by suitable means like grinding, chipping etc. The most commonly and widely used method is grinding. However, in the narrow grooves employed, conventional grinding tools are not suitable due to the limited accessibility. Special grinders, which enable the grinding tip to be positioned at the required place, inside the narrow groove are required. Besides this the grinding tool should also allow the manipulation of the grinding tip for effective removal of the defects. Conventional grinders are not suitable for this purpose as they cannot enter the narrow groove due to dimentional limitations of the grinders. The present invention provides a novel deep groove grinder used for grinding in narrow gap formed between two thick section materials comprising a tool holding shaft, a shaft supporting housing, a clamp for housing and an electric motorj said tool holding shaft being housed within said shaft supporting housing which is held in position with the help of said clamp, said shaft supporting housing being supported by said electric motor for operating said tool holding shaft for the grinder to work. In the abovementioned novel deep groove grinder, the shaft supporting housing contains a bearing for said shaft to rotate freely thus enabling the grinding load to be transmitted to said shaft supporting housing and thereby avoid damages to said motor shaft. The shaft supporting housing of the deep groove grinder of the present invention is additionally provided with slotted ends of the shaft supporting housing is mounted on a motor and is retained firmly in a predetermined position by suitable clamp. The tool holding shaft may further be provided with a collect at its tip which enables said grinding tip being held firmly to said shaft by a nut. The new deep groove grinder of the present invention can be fitted to conventional portable grinding machine. Usng this grinder, grinding at the required location inside a narrow gap welding joint, using thick section plate or pipe can be done effectively. The details of the new deep grinder assembly is shown in the drawings accompanying the Provisional Specification. In the accompanying drawings, Fig. 1 shows known joint design for narrow gap technique; Fig. 2 shows joint design for conventional technique; Fig. 3 shows deep groove grinder assembly of the present invention. The new grinder is shown to have a tool holding shaft (1), a shaft supporting housing (2). The said tool holding shaft is located within said shaft supporting housing (2) which is held is position with the help of a clamp (3). The shaft supporting housing is provided with an electric motor (4) for operating the tool holding shaft for the grinder to work. The shaft supporting housing contains a bearing/ which allows the shaft to rotate freely. The bearing, alongwith the support, also enables the grinding load to be transmitted to the shaft supporting housing and thus avoids any damage to the motor shaft itself. The shaft supporting housing has slots in the upper portion. The slotted end (5) of the shaft housing is mounted on the motor and retained firmly in position by a suitable clamp. The col 1et (6) provided at the tip of the shaft enables the grinding tip to be held firmly to the shaft by a nut. The new design, enables grinding to be carried out in narrow grooves having a width of 16 mm minimum. The new grinder can be used for grinding up to a depth of 200 mm. The new grinder is useful for both manual as we11 as mechanized mode. The new grinder possesses the following advantages over the conventional grinders - 1. it is simple in design; 2. it requires only few or less component parts; 3. it enables grinding to be carried out inside narrow, grooves with a gap of width of 16 mm (minimum); 4. its bearing supports enable smooth operation; 5„ its bearing supports sufficient strength to the slender extension shaft and prevents the bending load due to grinding pressure being transmitted to motor shaft; 6. its bearing supports enable application of greater grinding pressure; 7. it requires less maintenance; 8. it creates less vibration due to bearing supports; 9. its components do not require intricate machining, conventional machines can be employed; 10. fabrication cost low due to minimum machining requirements; better visibility of the grinding area; slender extension shaft allows more maneuverability of the grinding tool in the narrow groove; it can be used for grinding grooves upto a depth of 200 mm; its bearing supports to enable smooth rotation while transmitting the grinding pressure; its bearing support housing enables application of higher grinding pressure; its slender extension shaft allows more maneuberabi1ity of grinding tool; light weight of the component parts other than motor, results in less vibration and reudces the fatigue of the operator; its slender shaft allows grinding to be carried in grooves having a width of at least 16 mm. WE CLAIM: 1. A novel deep groove grinder for grinding in narrow gap formed between two thick section materials comprising a tool holding shaft (1), a shaft supporting housing (2), a clamp for housing (3) and an electric motor (4); characterized in that a tool holding shaft (1) being housed within said shaft supporting housing (2) which is held in position with the help of said clamp (3), said shaft supporting housing is provided with slotted end (5) in the upper portion, said slotted end is mounted on a motor and retained firmly in a predetermined position by said clamp, said shaft supporting housing (2) being supported by said electric motor (4) for operating said tool holding shaft for the grinder to work. 2. A novel deep groove grinder as claimed in claim 1 wherein said shaft supporting housing contains a bearing for said shaft to rotate freely which enables grinding load to be transmitted to said shaft supporting housing and thereby avoid damages to said motor shaft. 3. A novel deep groove grinder as claimed in claim 3 wherein said shaft is provided with a collet (6) at its tip which enables said grinding tip being held firmly to said shaft by a nut. 4. A novel deep groove grinder for grinding in narrow gap formed between two thick section material substantially as herein described and as illustrated in the drawings accompanying the provisional specification.

Documents:

809-del-2003-abstract.pdf

809-DEL-2003-Claims.pdf

809-del-2003-complete specification (granted).pdf

809-del-2003-correspondence-others.pdf

809-del-2003-correspondence-po.pdf

809-DEL-2003-Description (Complete).pdf

809-del-2003-drawings.pdf

809-del-2003-form-1.pdf

809-del-2003-form-19.pdf

809-DEL-2003-Form-2.pdf

809-del-2003-form-3.pdf

809-del-2003-form-4.pdf

809-del-2003-form-5.pdf

809-del-2003-gpa.pdf