US2073592A - Leather drying - Google Patents

Description

, .March 9, 1937. w BACKUS 2,073,592

LEATHER DRYING Filed NOV. 26, 1935 INVENTOR: 7mm, T Backus,

Patented Mar. 9, 1937 LEATHER DRYING Wallace '1'. Backus, Philadelphia, Pa., assignorto J. Edwards & 00., Philadelphia, Pa., a corporation of Pennsylvania Application November 26, 1935, Serial No. 51,576

2 Claims.

My invention relates generally to drying methods and apparatus and particularly to leather drying methods and apparatus. In the past, leather drying. has been done -both by exposure 5 to the atmosphere and by machine methods to speed up the process. The dimculty with the former method is its slowness and lack of control. Frequently atmospheric conditions are not conducive to drying and expensive delays from this cause are normal occurrences. The machine methods which attempt to speed up the drying process have the common disadvantage of impairing the structure of the leather and consequent- 1y producing an inferior grade of leather. Many involved methods and machines have been proposed to overcome the dangers of rapid drying of leather and particularly shoes and yet the problemremains of accomplishing the objective by a simple and practical means. How can shoes be dried-at different stages of their manufacture with rapidity and independent of the atmospheric conditions without impairing the structure of the leather or of the partially constructed shoe? My invention solves this problem by a departure from the usual type of drying methods and machines which use heated air and rapidly moving air currents. These two properties of the drying medium are lacking in my invention and it is their absence which to a considerable extent the detrimental effect of heat and strong currents of rapidly moving drying medium and abstract moisture from the leather without distorting its structure, either surface or internal.

Consequently one of the objects of my invention is the provision, of a simple method and machine which will rapidly dry leather or other substances independently of atmospheric conditions and without injuring the structure of the leather or the workpiece. Another object of my invention is the provision of such amethod and machine which may take advantage of satisfactory atmospheric conditions by using the atmosphere as a drying medium at such times. Another object is'the provision of a means of leather drying which is permanently open to the workmen without subjecting them to the discomfort of heated blasts of air. Other objects and advantages of my invention will become apparent from the detailed description of a preferred embodiment thereof which follows and which has reference tothe. accompanying drawing which shows a side view of my invention partially in section. 55 My invention comprises generally, as will appear in the drawing, drying units I, a d'ehucharacterizes my method. and machine. I avoid midifying unit 2 and conduit 3 and a booster fan 4. The drying'unit l comprises a sturdy frame 5, sprocket wheels 6 mounted at the ends of shafts 8, a movable rack 1 running on the sprocket wheels 6, a motor ll secured to the frame and 5 connected to one of the sprocket wheels 6 by reduction gears l2 and. I3, and a hood l4 covering the upper portion of the frame 5 and rack I. The movable rack I operates on the sprocket wheels 6 after the manner of the well known endless chain. 1 Each rack board I5 is pivotally suspended between the rack chains l6 so that the weight of the board i5 and shoes l'l keep the boards l5 from turning over as the chains l6 travel about their sprockets 6. The shoes I! fit in openings in the rack boards and no other fastening is required. of course, many other forms of racks and work holders are well known in the art and they could be substituted here. For this reason the structural details of the drying unit I have been omitted as irrelevant to the invention, and conventional indications adopted. The motor I l moves the rack i very slowly through the reduction gears l2 and I3.

The 'dehumidifying unit 2 may be one of the several types now well understood in the art and obtainable on the general market. It must, however, be of the type which dehumidifies the air without substantial heating ofthe air which leaves the dehumidifying unit. An incidental rise of temperature amounting to 10 or 20 above the atmospheric temperature would not be detrimental to the operation of my invention, but any substantial heating of the air would partially if not wholly defeat the purposes of my invention. I wish, therefore, to distinguish between incidental- 1y heated air or drying medium and air or heating medium which has been purposely subjected to a definite heating process. In the former there are comparatively small changes of temperature within about 20; in the latter there is a relatively large increase of temperature.

The hood I4 is secured to the upper portion of the frame 5 and leaves a substantial portion of the rack I exposed for access by workmen who place the shoes I! during the motion of the rack I. Because the hood I exposes a substantial part of the rack I, a working station can be positioned adjacent the rack I eliminating an intervening work transfer belt which would be necessary in the case of a hood closed at the bottom.

A closed hood would require a work transfer belt to carry work out of the drying unit to the workman. The top of the hood I4 is connected to the conduit 3 through a butterfly valve .20 by means 5 of which the slow flow of the drying medium is controlled for each individual drying unit I.

The conduit 3 which connects the drying unit I to the dehumidifying unit 2 is equipped with an atmospheric connection 2| through which the atmosphere may be admitted when suitable as a drying medium. The connection of the conduit 3 to the hood I4 is at such an angle and position that the drying medium does not come into direct contact with the shoes I! as it moves out of the conduit 3. A baflle could if desired be supplied to further deflect the incoming drying medium from directly flowing on to the moving shoes IT. A butterfly valve 22 controls the atmospheric connection 2|. Another butterfly valve 23 controls the flow of drying medium from the dehumidifying unit 2. All the butterfly valves 20, 22 and 23 have operating chains 24 accessible to the operator from the floor.

The booster fan 4 installed in the conduit 3 may be of any slow running type. Its purpose is to insure a slow and gradual diffusive movement of the drying medium through the conduit 3 and in the hood l4. It is important that this fan 4 keep the drying medium in a state of gradual progress along its course Without developing any well defined or rapid air currents.

While the operation of my invention has been described to some extent in connection with the above detailed description of the apparatus, the following additional description of its operation will behelpful, particularly in fully understanding the method on which the above apparatus works. First the dehumidifying unit 2 is started and the drying units I are filled with dehumidified air by opening the butterfly valves and 23. The motor H is started and the rack 1 begins to move slowly. A workman who has a work station at the bottom of the rack I now places shoes I? I on the rack boards l5 as he receives these shoes I! from the preceding work station. It is to be noted here that this work station at the bottom of the rack 1 would not be possible were it not for the fact that the rack l is exposed which would be impossible in the case of a heated drying medium. The drying medium gradually moves in through the top of the hood I4 well above the shoes l'l moving on the rack 'l at the top of the hood I4. This avoids a direct movement of air on to the shoes I! and causes a gentle diffusion of the drier air from the top of the hood l4 toward In case the unconditioned atmosphere is suiflciently dry to serve as a drying medium, it can be admittedthrough the atmospheric connection 2| as long as the dry atmospheric condition continues. It is thus seen that my invention results in a rapid drying of the shoes I! without the deleterious effects that frequently result from the use of heated air in blasts or rapid currents. Instead of controlling the blasts and the amount of heat as has been admitted in the. prior art, my invention avoids them. The apparatus is simple in construction, positive in its operation and efficient in its results. It eliminates a number of steps that have been resorted to in the prior art to avoid the deleterious effects on leather when the drying is artifieally speeded up and accomplishes an economy with better results.

While my invention has been described in some detail with reference to a specific embodiment, various changes in the form of the apparatus used and of the steps of the method employed are within the contemplation of the invention and such changes should not be admitted to constitute a departure from the spirit of the invention as hereinafter claimed.

Having thus described my invention, I claim:

1. A shoe drying apparatus comprising a vertical movable rack in which the horizontal movement is relatively small in comparison to the vertical movement, a dehumidifying unit producing a drying medium at substantially atmospheric temperature, an open bottomed hood attached to said dehumidifying unit by a conduit iii having a substantially horizontal discharge into the top portion of the hood, said hood being suspended over the upper portion of said rack to form the discharged drying medium into a slowly changing body merging with the atmosphere at its open end, and a means for slowly introducing the dehumidified medium by a gradual diffusion from the top of said hood.

2. A shoe drying apparatus comprising adehumidifying unit producing a drying medium at substantially. atmospheric temperature,- a discharge conduit leading from said unit, an open bottomed hood connected to the discharge end of said conduit, said conduit being positioned at substantially the top of said hood and directed to discharge the drying medium substantially hori-. zontally, and a vertical rack having its upper portion under said hood for moving the shoes up and down through said hood, said rack being of such proportions that the horizontal'movement of the shoes in the hood is relatively small in comparison to the vertical movement.

WALLACE T. BACKUS.

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