Патент USA US2405101код для вставки
Patented July 30, 1946 2,405,101 UNITED STATES PATENT OFFICE 2,405,101 METHOD OF RECONDITIONING FILES Robert S. Truesdell, Los Angeles, Calif., assignor of thirty-?ve one-hundredths to Fred Everett Howell, Long Beach, and twenty-‘?ve one-hun dredths to Frank Walker Harrington, Los An geles, Calif. No Drawing. Application January 1, 1944, Serial No. 516,741 4 Claims. (01. ‘IS-24) 1 2 This invention relates to a method of treating steel ?les to accomplish sharpening and recon set forth in order to enable-persons skilled in the art to carry it into effect with a high degree of efficiency, but it. will be apparent that ‘the method can be modi?ed within limits without de ditioning thereof. The invention contemplates and has as its pri mary object the provision of a method of recon parting from the spirit of the invention. ditioning and sharpening steel ?les such as to be In carrying out my invention the following con secutive steps are employed: applicable to the treatment of ?les either before or after being used to effect sharpening thereof First step and which is particularly adapted to recondition 10 The ?les to be treated, preferably in a batch, ing ?les after their having become oxidized, or are ?rst immersed in an alkali bath capable of worn, or rendered ine?ective by clogging of the dissolving grease, oils and fats and also capable toothed surfaces thereof. of acting as a solvent for particles of aluminum, Another object is to provide a method of chemi and. which bath preferably consists of a 25 to 35% cally treating steel ?les whereby various sub stances accumulated on the toothed surfaces of the ?le and which interfere with its proper use may be removed ‘and the teeth of the ?le slightly etched so as to sharpen the ?le. Another object is to provide a method of the above character which is extremely rapid in its action and is adapted to the treatment of ?les in batches to the end of enabling the attainment of a large voutput; in a short time and whereby the reconditioning of ?les may be so economically effected as to render practical the commercial rejuvenation of ?les on a large scale. Another object is to provide a process for chem caustic soda solution. The ?les are boiled in this solution for suchlength of time as to effect re moval of all particles of aluminum which may have ‘accumulated on the ?les and at the same time remove at least a-portion of such grease, oil and fat as may-have been deposited thereon. Thirty minutes of such hot alkaline bath is ordi narily'su?icient to accomplish this Cleansing ac tion.v .FAfter completion of the bath, the ?les are removed from the solution and .while hot are rinsed with a spray of cold water applied at nor maltemperature and. at the pressures of domestic water supply systems, usually about 85 pounds, for a period of ?ve minutes or thereabouts to ef fect sudden cooling of the ?les and their conse as not to be detrimental to the ?les under treat ment and which consequently results in little or 30 quent contraction from their expanded condi tion occasioned by the action of heat in the boil no loss of ?les because of damage thereto While ically reconditioning and etching steel ?les such processing. A further object is to provide a ?le recondition ing and sharpening process embodying a step whereby the processed ?les will be rendered free of subsequent detrimental action of chemicals employed in the process. Other objects and advantages will appear here inafter. ' lng operation. This rinsing and cooling opera tion may also be effected by immersing the ?les in cold Water. The expansion and contraction of the ?les serves to effect loosening of some ma terial embedded in the crevices of the ?les due to differential in expansion and contraction of di?erent substances. This rinsing operation also serves to wash the The method constituting the subject hereof in 40 ?les to remove loose particles therefrom and at the same time effect cleansing the ?les of at least volves the employment of alkaline baths and acid the major portion of the alkali solution as may baths which generally considered have been used cling thereon. heretofore in the cleansing of metallic surfaces Second step particularly in removing oxides and in pickling operations, and also involves the employment of ,2. 15K The washed ?les are submerged in an acid bath sulphuric acid and nitric acid which have long capable of dissolving and removing any grease, been used in chemically conditioning ?les. My invention while embracing these old features is characterized by the employment of certain spe oil, fat, tar, pitch and similar substances which may be present thereon after completion of the alkali and washing treatment, and also capable ci?c consecutive steps embodying the employment 50 of removing iron oxide or rust accumulated on of alkaline and acid baths of particular natures the ?le and at the ‘same time dissolve ?ne par and in a particular fashion, together with inter ticles of iron or steel and silver which may be mediate washing operations which I have found deposited in the crevices of the ?le. This acid to be essential to proper conditioning of ?les and bath preferably comprises a mild solution of sul which results in a product possessing a high 55 phuric acid. A ?ve to ten per cent solution is standard of quality not subject to deterioration satisfactory. as the result of the acid treatment. In setting forth my method herein the several time, temperature and strength of solution fac tors, together with speci?c substances used will be The ?les are immersed in this acid bath for a period of ?fteen minutes or thereabouts during which time the solution is maintained at a tem perature of 160° F. or approximate thereto. How 2,405,101 3 ever, care must be?exercised to avoid the bath reaching a temperature in excess of 180° F. for the reason that a temperature higher than this is liable to detrimentally affect the points of the ?le teeth. This acid bath will serve to remove the sub stances above speci?ed as well as others subject to being dissolved by the action of sulphuric acid of the strength and in the time stated, and will also act on removal of such substance to mildly -a attack the toothed surface of the ?le so as to ‘effect a slight sharpening action on the ridges or teeth of the ?le. As a substitute for commercial sulphuric acid I have found that the product known as “Sani?ush” is‘ highly satisfactory when used in the range'of proportions speci?ed for sulphuric acid. This product comprises a mix ture of sodium bisulphate, sodium chloride and magnesium silicate. The ?les are removed from this acid bath when suf?ciently cleansed and are rinsed in a water bath or spray for about ‘?ve minutes to effect 4 valve, to eifect control of the temperature of the. nitric acid solution and whereby the tempera ture of the solution may not only be maintained at not more than 180° F. but may be varied from time to time to meet varying conditions. The lower the temperature of the nitric acid solution the slower will be its action and conversely the higher its temperature the more rapid its action. There are occasions when a slow action is desir able and times when a faster action is wanted and accordingly regulation of the temperature of the solution becomes quite important in commer cial reconditioning of ?les. There are limitations as to the length of time the ?les may be treated in this bath without dam age which period varies, however, as to the condi tion of the ?les under treatment and also the tem perature and strength of the nitric acid solution. The lower the temperature of the solution and the weaker the solution the greater the period of time during which the ?les may be immersed in the solution. I have found in practice that a period of ?fteen minutes of submersion of the ?les in the nitric acid solution of the strength above stated and at a temperature of about 160 degrees is ordinarily suf?cient to accomplish re moval of copper and its alloys from the ?les, but removal of loose particles from the ?les and also remove the sulphuric acid clinging thereto. Some ?les may be adequately cleaned and re conditioned after the completion of this second step, particularly ?les ‘that have become fouled where babbitt or lead are to be decomposed a by oxidization, those that have been used solely longer period may be required. However, what in ?ling aluminum, silver and steel, and such ?les that are coated with pigments and oily, greasy, 30 ever period is necessary to effect the requisite ac tion, such peripd is preferably, though not neces or resinous materials, or other materials that are sarily consumed in a series of immersions of short readily soluble in either caustic soda or weak duration, for example, of three minutes each. solution of- sulphuric acid. Any ?les that may By so doing the extent of the action of the nitric be deemed inadequately reconditioned at the com acid may be watched from time to time so as to pletion of this second step may be treated as set minimize possibility of excessive corrosive action forth in the last step to be later described. How on the ?les. ever, the'essence of the present invention resides When by examination it is determined that the in subjecting ?les to the hereinafter recited steps nitric acid treatment has accomplished the de in continuation‘of the speci?ed ?rst and second steps, since the‘ greater majority of ?les requir- _ sired result of removing the softer metals and slightly etching the teeth of the ?les, the latter ing reconditioning have dulled teeth which will not be adequately sharpened by the named alkali are again subjected to a thorough washing ac and acid‘ treatments, and besides have been used in ?ling soft metals such as copper, brass, bronze, lead, zinc and other metals or alloys which will not be affected by the alkali and acid speci?ed. tion by immersing and agitating in water to re-_ Third step spraying operation ordinarily is not adequate move the nitric acid solution and any other sub stances as may be subject to removal by such washing. Water spraying of the ?les after treat ment with nitric acid may be employed but such when applied to a batch of ?les since impact of The ?les cleansed as above described are then immersed in an acid bath capable of digesting 50 the spray on some of the ?les will act to knock the soft metals and their alloys including copper, brass, bronze, babbit, lead and zinc, and also capable of effecting an etching or sharpening action on the teeth of the ?le. This acid bath preferably comprises a 7 to 10 percent solution of nitric acid. In subjecting the ?les to the action of the nitric acid bath it is essential that the temperature of the solution be maintained su?iciently low as not acid therefrom onto other of the ?les therefore rendering it possible for retention of nitric acid on at least some of the ?les with consequent damage thereto. Even if a spraying operation be used it is necessary to follow it with immer sion and agitation in a water bath in order to insure thorough removal of the nitric acid. Fourth step The ?les are then immersed in a ?fty per cent to blister or mutilate the ?les. I have determined 60 that temperatures in excess of 180° F. are liable ‘ solution of sulphuric acid and allowed to remain to damage the ?les and accordingly it is neces sary, in order to insure a high standard of quality therein a period of from thirty to forty minutes whereby such metals or other materials as may have escaped the earlier sulphuric acid treatment and which are subject to decomposition or dis solution under the action of such solution will be in the reconditioned product, to treat the ?les in the nitric acid solution at a temperature ranging downward from 180° F. Since considerable heat removed. The temperature of this solution is generated by the action of the nitric acid solu should not exceed 180° F. tion in digesting metallic particles on the ?le, especially when'the solution is fresh, the temper Fifth step ature of the solution is regulated by subjecting 70 At the conclusion of this second sulphuric acid the solution to the action of a cooling medium treatment the ?les will be thoroughly cleansed such as a refrigerant flowed through tubes sub and will be well sharpened but ordinarily ?les merged in the solution. The ?ow of the refrig erant is controlled in a conventional fashion as that were considerably worn will be improved by by an automatic thermostatic controlled feed 75 a further sharpening action. To accomplish this 5 2,405,101 the ?les are immersed in boiling water. This hot water treatment constitutes an important step in the process since on immersion of the acid coated ?les in boiling water an instant accelerated action of the acid takes place which is particularly mani fested 0n the tips of the ?le teeth in increased sharpening thereof. This action is limited to 6 The process herein set forth is especially ap plicable to the treatment of ?les on a large scale, it being subject to being carried out by the em ployment of a series of cauldrons containing the several liquids which are arranged in the consec utive order of their use. Batches of ?les sup ported vertically in spaced relation to each other such short duration as to insure against excessive on a portable rack are conveyed to and from the etching of the points of the teeth by reason of the acid being quickly weakened by the hot water. 10 several cauldrons and are lowered into and with drawn from the baths by suitable hoisting mech The ?les are maintained in this hot bath for anism; the ‘ ?les being previously classi?ed or a su?icient length of time to dilute the acid cling graded in each batch according to similar char— ing to the ?les to at least near neutral. A period acteristics so that the ?les in batches needing of ?ve minutes or thereabouts is ordinarily ade quate. The ?les will be thoroughly cleansed and 15 di?erent times of treatment may be variably treated according to requirements and so that all sharpened at this stage of their treatment. the ?les of each batch will be uniformly treated. Sixth step However, it may be that at the end of any step in the process some ?les in a batch may not be ade Immediately or shortly after removing the ?les quately processed in which event such ?les may from the hot water bath they are subjected to be removed from the batch at any stage in the the action of a neutralizing agent, as by being process and be retreated with any of the steps to submerged in a boiling alkaline bath such as to insure its proper reconditioning. insure any acid clinging to the ?les being ren I claim: dered neutral. This bath preferably consists of 1. The method of reconditioning ?les consist a ?ve to ten per cent Baumé solution of sodium 25 ing in ?rst subjecting the ?les to the action of a carbonate or a solution comprising one pound or solvent of aluminum, grease, oils, fats, pigments thereabouts of pulverized sodium carbonate dis~ and the like, washing the ?les, then immersing solved in ?fty gallons of water, together with a the ?les in a weak solution of sulphuric acid, one per cent solution of bichromate of soda. The ?les are submerged in this neutralizing solution 30 washing the ?les, subjecting the ?les to the ac tion of a nitric acid solution, washing the ?les, for such length of time as to obtain the desired again immersing the ?les in a sulphuric acid so result. Boiling the ?les in this solution for ten minutes is ordinarily sufficient. lution stronger than that previously employed; immersing the ?les in boiling water whereby an The ?les on being thus subjected to the hot neutralizing agentare removed therefrom and 35 instant acceleration of the action of acid clinging to the ?les will occur and effect a sharpening of while hot are suddenly cooled by submergence in the ?le teeth, immersing the ?les in a neutraliz cold Water in which the ?les are thoroughly ing bath, washing the ?les, and ?nally coating the washed. About ?ve minutes will suf?ce for this ?les with a rust protective material. treatment. 2. In a process of sharpening steel ?les involv Seventh step 40 ing subjecting the ?les to the action of nitric acid While the ?les are in condition for re-use on solution ‘to effect etching of the ?le teeth followed being dried at the conclusion of the preceding by water washing, the steps of immersing the ?les step, they are subject to becoming oxidized on in a sulphuric acid solution immediately followed exposure to air and moisture and accordingly it by immersion of the ?les in boiling water whereby is vitally important in the reconditioning of the ' an instant acceleration of the action of acid ?les on a commercial scale that they be given a clinging to the ?les will occur and effect further and ?nal sharpening of the ?le teeth. protective coating such as to obviate rust. For this purpose the ?les on being ?nally washed in 3. In a process of sharpening steel ?les involv cold water at the end of the preceding step are ing subjecting the ?les to the action of nitric acid immediately given a protective coating as by be solution to e?ect etching of the ?le teeth followed ing submerged in a solution of soap and water. by water washing, the steps of immersing the ?les This solution is preferably prepared from a soap in a sulphuric acid solution immediately followed having a vegetable base such as the soap known by immersion of the ?les in boiling water whereby as “Palm Olive.” Four hand bars of such soap dissolved in ?fty gallons of water makes a satis factory soap solution for the purpose. The ?les are immersed in this soap solution long enough an instant acceleration of the action of acid clinging to the ?les will occur and effect further and ?nal sharpening of the ?le teeth, then im mersing the ?les in a neutralizing alkaline bath. to insure thorough coating thereof. Merely dip 4. In a process of sharpening steel ?les, the ping the ?les in the solution is ordinarily su?i steps consisting in immersing the ?les in a seven cient. On removing the ?les in the solution they 60 to ten per cent solution of nitric acid, for a period are dried in atmosphere at room temperature of ?fteen minutes, to sharpen the teeth of the whereupon the ?les will be coated with a pro tective ?lm of soap whereby the ?le surfaces will be retained free from rust. The recondi tioned product is then ready for use or for pack ?les, removing excess heat from the solution oc casioned by reaction of the acid on the ?les by means of a refrigerant to maintain the temper~ 65 ature of the solution below 180° F. during immer aging or storing. sion of the ?les, then water washing the ?les, then The total time required to perform all the steps immersing the ?les in a solution of sulphuric acid of this process to and including applying the ?nal then immediately immersing the ?les in boiling coating, assuming no appreciable delay occurs be tween any of the operations, will be from two to 70 water to effect further sharpening of the teeth of the ?les, and thereafter subjecting the ?les to an two and one-halt‘ hours, thus greatly reducing the acid neutralizing treatment. time ordinarily consumed in the reconditioning of ?les. ROBERT S. 'I'RUESDEIL.