Title of Invention

A NEW, ERGONOMIC WELDING SCREEN FOR MANUAL METAL ARC (MMA) WELDERS

Abstract

The present invention, the new, ergonomic welding screen, is of low-cost and suitable for use by the Manual Metal Arc (MMA) welders of industrially developing countries as compared to the extremely costly and sophisticated electronic type of photochromatic welding screen at present being used by the MMA welders of industrially developed countries. The welding screen could be fitted onto the head of the manual metal arc (MMA) welders to increase their field of vision through the screen and also to make their left hand free to perform other work. The screen itself is fitted to a safety helaet to protect the welders from overhead stray objects and other materials falling on the head. The screen could be lifted over the helmet when it is not in use. When required, a slight nodding of the head could put it back into the welding position. Arrangements have been made so that a small downward movement of the chin lifts a small portion of the ultra-violet (uv) protective glass filter and thus enables the welder to fit the electrode to the holder, to see the electrode-tips and the working site, without removing the screen from the head as is done with the existing screen. The new design provides better protection from the spatters and hot, toxic fumes coming from the arc resulting in enhancement of their efficiency, performance and productivity and improvement of the occupational safety and health of the MMA welders.

Full Text

This invention is related to a very low-cost welding screen for use by the Mammal Metal Arc (MMA) welders of industrially developing countries. The hand-held welding screen, as available in the Market and generally used by the Indian MMA welders, consists of an opaque body with a window, near its top portion at the front, fitted with an ultra-violet (uv) glass filter and two glass filter-covers of specified sizes, which allows the welder to see the welding operation, yet prevents the harmful uv radiations to fall on their eyes, and a handle to hold by hand, attached to the bottom portion at the back. The use of the existing welding screen leads to reduced efficiency and performance and creates several hazardous problems for the MMA welders, such as : i) During work, a right handed MMA welder protects his eyes and face from the uv and thermal radiations by bringing the welding screen, held by the left hand, in front of the face and removing it when the arc is off to see the work. This resulted in unnecessary and continuous holding and carrying of the welding screen and also a large number of hand movements throughout the day's work causing an early fatigue, which could be avoided. ii) The existing welding screens keep the left hand of right handed welders always engaged, thus involving in static muscular work with the heavy screen, which leads to quick fatigue. iii) Most of the existing screens are not suitable to give complete protection of the faces and eyes of the MMA welders from the thermal and uv radiations, flying hot metal spatters and hot, toxic fumes coming from the arc. This resulted in a large number of eye and skin injuries and burns, and other impairments of the MMA welders. iv) Very poor ambient ventilation in between the welders' breathing zone and the screen causes inhalation of hot, toxic fumes coming from the arc, resulting in serious respiratory distress and illness. v) The welders' visibility through the screen is very poor causing difficulties in essential viewing of the tip of the electrode, the work and the working areas during welding. vi) While working within the shop-floors, there are every chance of stray objects or other materials falling from the overhead travelling and other cranes or due to people at overhead work. The objective of the present invention is to provide a new design of a welding screen for the MMA welders, which can remove most of the abovementioned difficulties and problems. The new, ergonomic welding screen would also provide better occupational safety and health of the MMA welders leading to enhancement of their efficiency, performance and productivity. i) The handle of an existing design of a welding screen was removed and the screen was fixed to a safety helmet so that it could be fitted on to the head of an MMA welder to make his left hand free to perform other work. Thus Muscular fatigue of the left hand caused by the static work in continuous holding the heavy protective screen could be avoided. ii) The inner surface of the helmet is fitted with an "adjustable head-band so that people with different coronal circumferences could wear it without any difficulty. The new design is also fitted with an adjustable chin-strap and a leather chin-piece. iii) As the screen is fitted on to the head, it remains much closer to the welder. As a result, the visual field through the screen was three times more than that with the existing one. iv) The screen was fitted to the safety helmet in such a way that the screen could be lifted up over the helmet when it was not in use. When required, a slight nodding of the head would put it back into the position suitable for welding. v) For a better view of the surroundings and the tip of the electrode and also during inspection, grinding and chipping tasks, the welder could also lift the screen up over the helmet instead of removing it from the head. This process of lifting the screen not only provides better view of the work-site but also facilitates better and effective ambient ventilation for the welders. vi) A number of holes are also made on the helmet for better ventilation. Some holes are made on the two sides of the raised portion of the top of the helmet, one further away from the other on the opposite side in a zig-zag pattern to avoid reducing its structural strength. Other holes are made on the lower portion of the back of the helmet in a similar pattern. The position of the holes are selected in such a way that the arc rays, fumes or spatters could not enter the helmet through these holes. During welding, the air within the screen becomes quite hot and passes out through the holes made on the helmet and relatively cooler air then enters the screen. This also prevents misting of the glass window. If any fumes enter by chance, this could also be passed out easily. vii) A light-weight wooden box frame is fitted to the window of the welding screen. viii) In the wooden box frame, four grooves are cut. In the first (the anterior most) and the fourth (the posterior most) grooves, two ordinary glasses are fitted with the sides sealed to prevent the entry of hot, toxic fumes coming from the arc. ix) One standard sized ultra-violet (uv) protective glass filter is cut longitudinally into three nearly equal segments. In one of these segments, two small holes are made just at the two upper corners. x) In the second groove of the wooden box frame, two of the three segments of the uv protective glass filter are fitted and sealed in such a way that one piece could be at the top of the groove and the other one at the bottom. The gap between them would be slightly less than the width of the remaining third segment. xi) In the third groove, the uv protective glass segment having- two holes, is hung is such a way that it could fill up or just overlap the gap and can be moved up and down easily. It is then connected to a leather chin-piece with the help of two small, light- weight, flexible, nylon cords which pass over two very small and light-weight aluminium pulleys fitted onto the left and right sides of the upper part of the welding screen just over the wooden box frame. xii) A small downward movement of the chin with the leather chin- piece raises the small portion of the uv protective g-lass filter segment so that the welder, without removing the screen, could see the electrode-tips and the objects to be welded, through the gap. The newly recruited MMA welders may need some special training and practice to acquire the desired skill for the jaw movements necessary to use the new welding screen. In the traditional method, the hand held screen has to be removed from the visual field for the same purpose of enabling the welder to see the electrode tips, etc. Thus the new design provides better protection of the MMA welders from the uv and thermal radiations, flying hot metal spatters and hot, toxic fumes coming from the arc. xiii) In the new design, the wooden box frame of the window could easily be removed and the uv g-lass filters cleaned and plain glass covers replaced, as and when required, for regular maintenance. xiv) In the alternative prototype design which is specially suitable for over-head work, the two-pulleys system has been replaced by a two- springs system. DRAWINGS & DESCRIPTIONS The new, ergonomic welding screen, according to this invention is illustrated in the accompanying drawings. Figure 1 is the schematic diagram of the front view of the screen and the safety helmet, where 'W' is the wooden box frame of the window, holding two pieces of the plain glass covers with three equal sized overlapping uv protective filter glass segments - 'uv1', 'uv2' and 'uv3'. 'uv1' and 'uv2' are the two uv protective filter segments fixed to the upper and lower parts of the of the wooden frame respectively. Another uv protective g-lass filter segment, 'uv3', can slide up and down within the wooden box frame. The nylon cords, 'NC's. are tied onto the two upper corners of the 'uv3' and pass over the two aluminium pulleys, 'P's, and enter the screen through the holes, 'H's. Figure 2 is the schematic diagram of the front view of the screen and the safety helmet, where the uv protective movable filter glass segment (uv3) has been lifted upwards by a downward movement of the chin and thereby creates an opening '0' through which the welder can see the work. Figure 3 is the schematic diagram of the side view of the screen and the safety helmet, where 'S' is the safety helmet fitted to the welding screen. It has a number of holes ('HS's) for better ventilation. 'HB' is the adjustable head-band of the safety helmet. Figure 4 is the schematic diagram of the side view of the screen and the safety helmet, where the screen has been lifted over the helmet, showing 'CS' as the adjustable chin-strap and 'CH' as the leather piece fitting the chin. Figure 5 is the cross sectional view of the window of the screen showing the placement of the two plain glass covers (Pg1 and Pg2) and three uv protective filter glass segments (uv1, uv2 and uv3). We claim : 1. The new ergonomic design of the welding screen for the Manual Metal Arc (MMA) welders comprises of a safety-helmet fitted with the screen at the top. 2. The welding screen as claimed in 1 is of very low-cost as compared to the extremely sophisticated and costly electronic type photochromatic welding screen subserving similar functions. 3. The welding screen as claimed in 1 wherein, one standard sized uv protective glass filter is cut into three equal segments and is fitted to an wooden box frame. 4. The welding screen as claimed in 1 wherein, a small downward movement of the chin, with the help of a leather chin-piece connected with two nylon cords passing over two aluminium pulleys, lifts a small part of the uv protective glass filter segment covering the opening. 5. The welding screen as claimed in 1 wherein, there are adjustable head-band and chin-piece to fit MMA welders of different anthropometric dimensions. 6. The welding screen as claimed in 1 wherein, the wooden box frame of the window could easily be removed and the glass filters cleaned and plain glass covers replaced, as and when required, for regular maintenance. 7. The welding screen as claimed in 1 wherein, an alternative design suitable for over-head work replaces the two-pulleys system by a two-springs system. 8. The welding screen as claimed in 1 provides better protection of the faces and eyes of the welders from the thermal and uv radiations, flying hot metal spatters and hot, toxic fumes coming from the arc resulting in reduction of a large number of eye and skin injuries, heat burns, respiratory distress, illness, etc. 9. The welding screen as claimed in 1 makes the left hand of the MMA welders free to perform other work, thus muscular fatigue of the left hand caused by the static work in continuous holding- the heavy protective screen can be avoided. 10. The welding screen as claimed in 1 wherein, the visual field through the screen is three tines more than that with the existing one. 11. The welding screen as claimed in 1 provides better view of the work-site but also facilitates better and effective ambient ventilation for the welders. 12. The welding screen as claimed in 1 provides better protection of the MMA welders from the stray-loads or other materials falling from overhead travelling and other cranes or due to people at overhead work. 13. The welding screen as claimed in 1 would also provide better occupational safety and health of the MMA welders leadine to enhancement of their efficiency, performance and productivity. The present invention, the new, ergonomic welding screen, is of low-cost and suitable for use by the Manual Metal Arc (MMA) welders of industrially developing countries as compared to the extremely costly and sophisticated electronic type of photochromatic welding screen at present being used by the MMA welders of industrially developed countries. The welding screen could be fitted onto the head of the manual metal arc (MMA) welders to increase their field of vision through the screen and also to make their left hand free to perform other work. The screen itself is fitted to a safety helaet to protect the welders from overhead stray objects and other materials falling on the head. The screen could be lifted over the helmet when it is not in use. When required, a slight nodding of the head could put it back into the welding position. Arrangements have been made so that a small downward movement of the chin lifts a small portion of the ultra-violet (uv) protective glass filter and thus enables the welder to fit the electrode to the holder, to see the electrode-tips and the working site, without removing the screen from the head as is done with the existing screen. The new design provides better protection from the spatters and hot, toxic fumes coming from the arc resulting in enhancement of their efficiency, performance and productivity and improvement of the occupational safety and health of the MMA welders.

Documents:

524-cal-1997-abstract.pdf

524-cal-1997-claims.pdf

524-cal-1997-correspondence.pdf

524-cal-1997-description (complete).pdf

524-cal-1997-drawings.pdf

524-cal-1997-form 1.pdf

524-cal-1997-form 2.pdf

524-cal-1997-specification.pdf