94 



THE INDIA RUBBER WORLD 



November 1, 1920 



a man's arm' can pass between tlie rolls and not be pinched. 

 \\ here the rolls cannot be thus separated, it may be possible to 

 separate them to such an extent that a guard can be used suc- 

 cessfully. A guard used in several factories consists of two hori- 

 zontal steel plates about VA inches apart, extending in between 

 the rolls. (See Fig. 7.) The lower plate does not extend so far 



Fic. 6. Xon-Slu' Floors .\re Necess.\ry Around Calenders 



inwardly as the upper plate, and this allows workman to place 

 the stock on the lower roll ; and if the travel of the roll should 

 carry his fingers forward they will strike the upper plate with- 

 out harm. To be successful, this guard must be constructed very 

 heavily, and be very rigidly attached to the machin?. A scraper 

 bar is attached to the lower section of the guard after the guard 

 is in place, and so adjusted to the roll that there is only a very 

 small clearance between the scraper and the roll. This scraper 

 is for any stock which may get around the lower roll and which 

 would have a tendency to roll up under the guard and bend it 

 out of shape. It must be urged most forcefully that a man who 

 is working on a calender with separated rolls shall never be trans- 

 ferred to another calender having its rolls in contact, for the 

 knowledge of not being subjected to danger on the first type, 

 forms a habit of placing the hands between the rolls, and this 

 habit will unconsciously be continued on the latter type and re- 

 sult in severe injury. 



All wind-ups and let-oflfs should have a stationary hand-wheel 

 for adjusting the tension in stock. This can be accomplished 

 by mounting the hand-wheel on the wind-up bearing, the outside 

 of the bearing having screw threads upon which the hand-wheel 

 adjusts itself against the friction disk. To hold the stock shell 

 bar within the wind-up spindle, a smooth ring should slide on 

 the spindle and cover the end of the bar. This ring can he locked 

 in position by a pin with a spring. No projecting set-screws or 

 pins should be placed on any revolving part of the wind-up. 



All idler rolls ought to be placed as far as possible from cal- 

 ender rolls. Particularly is this true where the stock passes be- 

 tween the idler and the calender rolls, for serious accidents have 

 occurred where the operator was caught by the stock and drawn 

 between the rolls. 



Gear guards and pipe railings as described under the subject 

 of mills, are equally adaptable on calenders. Fig. 6 illustrates 

 excellent guards. 



Non-slip floors are particularly necessary around calenders. 

 A concrete floor with carborundum treatment, previously de- 

 scribed, will not become slippery from scapstone because the 

 grains of carborundum cut the soapstone and prevent it from 

 adhering to the floor finish. Between the housings of the cal- 

 ender it is usually not practical to lay a concrete floor, and there- 

 fore a metal floor predominates. This metal floor surface ought 

 to be rough. Objections are often heard against this, and it is 

 contended that a rough floor may damage the tail end of the 



stock which drags along the floor before being wound up. How- 

 ever, this objection is greatly overdrawn. Fig. 6 shows such a 

 floor under a calender which has been doing a high grade of 

 work for years. 



Illumination for calender work is important, not only to safe- 

 guard the workman, but particularly to produce work of highest 

 quality. Too many calenders are being operated with local lights 

 attached to the macliine. The general lighting system described 

 for mill rooms is recommended for calender rooms, except that 

 tlic maximum amount of light should be given the calenders, and 

 a lower intensity in the aisles. The intensity on the calenders 

 ought to be 10 foot-candles uniform lighting, and about 5 to 

 6 foot-candles uniformly in the aisles. If glare is eliminated this 

 difference in intensity will not produce eye strain. 



The tendency in calender work has been toward increased 

 width of stock and greater lengths, which has produced rolls of 

 slock of great weight and unwieldy size, and consequently greater 

 chance of injury to operator. Careful consideration of methods 

 of handling heavy rolls of stock becomes very impcjrtant. An 

 electric or air hoist mounted on a trolley is perhaps the simplest 

 and (|uickest means of lifting these rolls. 



A calender may produce excessive heat or fumes, making it 

 advisable to install a ventilating hood above, and connected to an 

 exhaust fan. However, it is far better to have a high calender 

 room, preferably one story, with saw-tooth skylights to give 

 good ventilation and light. If the room has a low ceiling then 

 mechanical ventilation is necessary, especially during summer 

 months and times of high humidity. 



Where excessive soapstone or stock dusting accumulates on 

 the floor under the calender wind-up and let-off, a suction system 

 should be provided. This dust should fall onto and through a 

 latticed or perforated floor into a chamber from which it is drawn 

 into a duct and thence to a fan exhausting into a stack as de- 

 scribed for mill room ventilation. 



The vacuum cleaner principle has been applied to the cleaning 

 of liners and this obviates most of the flying dust around calen- 



Scraper slofhdVxHs'and 



P/afe tapped after Guard is installed 



Fig. 7. An Efficient Calender Guard 



der let-offs and wind-ups. A vacuum cleaner is of even more 

 importance in a calender room than in a mill room, for in ad- 

 dition to the benefit to workmen, tliere is an extreme necessity 

 for cleanliness of calendered stock. All pits and openings in the 

 floors should be free from rubbish and grease, and should have 

 proper curbs around them. 



CONCLUSION 

 The foregoing descriptions have covered mechanical safe- 

 guards which for a large part depend upon a little common sense 

 on the part of workmen in providing personal care. Workmen 



