US2848974A - Leather finish applying machines - Google Patents

Description

Aug. Z6, 1958 E. S. LEE lll LEATHER FINISH. APPLYING MACHINES 3 Sheetg-Sheet 1 Filed Feb. 14, 1955 inventan Edmund .S LgeIII `By his ttorney All-g. 26, 1958 E. s. LEE m 848,974

LEATHER FINISH APPLYING MACHINES Filed Feb. 14, 1955 i 3 Sheets-Sheet 2 5y his Attorney Aug. 26, 1958 r-:."s. LEE lu 2,848,974

. LEATHER FINISH APPLYING MACHINES l 'Filed Feb. 14, 1955 v s sheegs-sneet s 50 [n vento/ Edmzmd Lee1r By /zisttoTney i l i United States Patent LEATHER FINISH APPLYING MACHINES Edmund S. Lee III, Hamilton, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application February 14, 1955, Serial No. 487,745

3 Claims. (Cl. 118-63) The present invention relates to machines for applying liquid coatings to individual workpieces and more particularly to machines for applying such coatings, known as seasoning, to leather workpieces.

In leather manufacture the term seasoning is applied generically to liquid compounds for coating leather surfaces and to their application. These compounds are formulated with an aqueous base and contain a wide variety of materials. Some of the more representative ingredients include aniline dies for a penetrating color, finely ground pigments used for coloring and to hide minor surface defects, latex for bonding the pigments to the leather and wax for imparting a sheen to the finished leather. Seasoning compounds vary so greatly from tannery to tannery as well as between different types of leather that they must be referred to in broad generalities. Speaking in this manner it can be said that a finished piece of leather has four or iive coatings of different compounds. The first coat has a heavy percentage of pigment and no wax. In succeeding coats the ratio of pigment to wax is reversed until the nal or top coat contains no pigment and a heavy percentage of wax. Other materials are included in the various coatings to give a dressing for the leather surface which will adhere properly, is water proof to a degree, is color fast, is glossy and is of the desired color.

Leather, being an animal product, has none of the uniform properties found in synthetic materials. Therefore, it is not readily adapted to standardized handling techniques. This holds true in the seasoning process as well as in others. Spray application of liquid coatings has been only partially successful in providing automatic means for applying seasoning compounds. Compounds having a high percentage of pigment generally cannot be successfully sprayed for two reasons. First, the aqueous solutions will not level themselves as will oil paints so that a stippled effect results and second, proper adhesion is not obtained due to the high surface tensions of the leather and of these compounds. Therefore, these coatings are applied by the so-called brush machine and then smoothed out by workmen using plush covered paddles or swabs. This latter process is not only time consuming but requires a fair degree of skill on the part of the workmen properly to even out the coating.

Spray equipment for applying seasoning is automatic in that there is no physical skill needed for its operation but even so its rate is relatively slow. In view of other improvements in the tanning field there is need not only for automatic equipment but equipment capable of operating at a rapid rate.

It is therefore an object of the present invention to provide a machine for automatically applying all types of seasoning compounds to leather workpieces at a rapid rate.

To this end and according to the various features of my invention means are provided foi applying an excess of seasoning material to individual leather workrice u pieces carried by an open work conveyor and for thereafter stripping the excess material from the workpieces.

The seasoning material is applied in a solid curtain from at spray nozzles and a novel deection plate is provided to minimize foaming of the seasoning as it'returns to a sump.

An infeed conveyor is provided to facilitate feeding of workpieces without spilling seasoning compound.

Other novel features will be foundin the baiing means provided for controlling air from the air knife and dispersing it from the machine.

The above and other features of the invention including novel details of construction and combinations of parts will be more particularly describedwith reference to the accompanying drawings and pointed out in the claims.

In the drawings,

Fig. 1 is a side elevation of one form of seasoning machine in which the invention is embodied;

Fig. la is a fragmental section of the air knife seen in Fig. 1;

Fig. 2 is a section taken on the line II-II of Fig. 1 showing the means for applying seasoning material;

Fig. 3 is a plan View of the machine shown in Fig. 1;

Fig. 4 is a view ofthe air knife seen in Fig. 1 on an enlarged scale; and

Fig. 5 is a view of the seasoning applying means seen in Fig. 1 on an enlarged scale with certain parts being broken away for clarity.

Figs. 1, 2 and 3 show the general organization of the present machine. There is an infeed conveyor 1t) to which workpieces such as W (Fig. 3) are presented. A main conveyor 12 receives the workpieces from the infeed conveyor 10 and carries them first beneath a curtain of seasoning compound emitting from a series of nozzles 14. The excess seasoning is then stripped from the leather surface as the workpieces are carried beneath an air knife 16 which extends across the width of the conveyor 12. The excess seasoning returns to a sump 18 and the workpieces, after they pass beyond the air knife 16, are coated with a thin uniform film of seasoning. After removal from the conveyor 12 the workpieces are dried according to conventional practice.

The air knife 16 introduces many fundamental problems in handling leather workpieces as well as in applying the seaso-ning compound. The conveyor 12 must be of an openwork construction. That is, there must be openings through which air may pass so that there is no tendency for the air to bounce from the conveyor and lift the workpiece therefrom. Also there must be a minimum amount of turbulence as the air passes beyond the conveyor, for turbulence of air at the conveyor will cause the seasoning compound thereon to splatter and clog the air knife or have other undesirable results. l have therefore found it preferable to form the conveyor 12 from a plurality of stainless steel wire loops. These wire loops are spaced across the width of the conveyor on centers which are spaced according to the limpness of the type of leather to be handled. The conveyor 12 passes around rolls 20, 22 and 24 each of which may be grooved to receive the individual wires and thereby maintain their space relationship. The roll 24 is adjustably mounted to provide a tension adjustment for the conveyor 12. A single adjustment for all the wire loops has been found satisfactory although individual tensioning means could be provided if such were found desirable. The conveyor 12 is driven in the direction indicated =by the arrows -by a motor M through a gear box G and belt 26. The rolls 20, 22 are journaled at the ends of two side frame members 28 which are carried by uprights 30 and 32 on either side of the machine. A cross brace 29 extends between the uprights 32 to supplement the rigidity supplied by the rolls 20, 22. It will be noted that the uprights 30 are shorter. than the uprights 32 so that the upper or work bearing run of the conveyor 12 slopes downwardly away from the air 'knife 16 toward the nozzles 14 for reasons which :will

further appear.

The infeed conveyor 10 does not approach the air knife 16 and therefore may be formed in any conventional manner such as by a series of fabric tapes spaced acrossfits width as seen in Fig. 3. These tapes pass Aaround rolls 34 which are journaled near the ends of two frame members 36. The inner ends of the frame members 36 are secured to the frames 28 while their outer ends are supported by legs 38. The infeed conveyor 10 is driven by a belt 40 extending between the roll 20 and the outer roll 34. AIt will be noted that the pulley associated with the roll 34 is smaller than the pulley associated with the roll 20 as well as the rolls 34 being of smaller diameter than the roll 20. Thus the rate of the conveyor 10 is somewhat slower than the rate of the conveyor 12 for reasons which will become apparent below.

It will be noted that the entire conveyor 12 is coated with seasoning material with the exception of those areas covered by a workpiece as it passes beneath the nozzles 14. It is necessary that the conveyor be cleaned before a workpiece is again presented to it to prevent the 'back -of the next workpiece from being marked. For that purpose a wire brush 42 is journaled in the .ends of a tray 44 extending between the uprights 30 and fastened thereto (Fig. The tray 44 is provided with a cap 46 which has openings permitting thev passage of the individual loops of the conveyor 12 which also extend beneath the outer surface of the wire brush 42. Water is admitted to the tray 44 through a pipe 48 and an overflow pipe 50 is provided to maintain the level of water in the tray 44 constant. A belt 52 extends between the roll 20 and the brush 42 so the brush is at all times rotating as the wires of the conveyor 12 pass therethrough. The brushing action and the washing action thus clean the conveyor so that it always presents a l clean surface to a new workpiece delivered from the conveyor `10.

A supply of seasoning compound is provided in the sump 18. A pump P is provided for constantly circulating seasoning from the sump 18 to the nozzles 14. The seasoning material is drawn from the lowest portion of the sump 18 through a pipe 54 to the pump P. Since the compound is drawn from the lower portion of the sump where the heavier pigment particles would tend to settle it is therefore unnecessary to have any" further agitating means. From the pump P the seasoning compound flows through a flexible conduit 56'to a yoke arrangement 58 (Fig. 2) which leads to opposite ends of a header 60 to which the nozzles 14 are attached. The yoke arrangement 58 is secured to the side frames 28 by brackets 62. The nozzles 14 are ofy the so-called at spray type which produces a thin fanlike spray as indicated in Figs. l and 2. The nozzles 14 are positioned above the conveyor 12 at a point where the fan-like sprays converge upon one another before striking a workpiece. compound impinges upon the 4surface of theleather. While other means for applying the seasoning would sufce, I have found the described form preferable for two reasons. First, the at spray nozzles are adapted to use with relatively high pressures in the order of 30 p. Vs. i. which enable the seasoning material to strike the `surface of the leather and intimately wet the fibers thereof and thereby form the basis for good adhesion properties. Second, having the entire width of the workpiece wetted at the same time leads to uniform coloring yin the finished leather.

Because of the high pressure of the seasoning stream.

a problem arises if it strikes directly the reservoir of i seasoning in the sump 18. Due to certain ingredients Thereby a continuous curtain of r` back eddies.

in the seasoning material, the resulting agitation or turbulence would. cause a serious foaming of the compound. This problem has been successfully overcome by the provision of a deflection plate 64 which extends between the sides of the sump 18 with its upper surface arranged tangentially to the seasoning stream from the nozzles 14. Thus the seasoning stream impinges upon the plate 64 and is guided into the sump 18 as a solid stream with a very minimum of turbulence.

When a workpiece extends beneath both the air knife 16 and thc nozzle 14, a stream of air will flow toward the nozzles 14 and tend to breakup the solid curtain which they produce. Batfles 66, 68 extend across the width of the conveyor -12 and protect the seasoning curtain from this air. A single vbaille in some instances is sufficient. However, the use of multiple bales has been found preferable.

The air knife 16 comprises a plenum chamber 70 of rectangular section from which extend studs 72. The

studs 72 are adjustably mounted in links 74 which in turn are` pivotally connected to brackets'76 secured to either side frame member 28. The upper ends of the links-74 are'pivotally secured to turn buckles 78 which are carried by brackets also secured to either side frame 28.. The air knife itself is preferably formed by two blade members 82 (Fig. la) which are secured to the plenumchamber 70 by screws 84.k The inner faces of the blades 82 are spaced apart in parallel relationship through a substantial,

distance. The distance between these faces is adjusted in the range of .O15 inch to .035 inch to control the width f of the air stream forming the air knife. In order to prevent diffusion of the air stream it has been found preferable to form the outer faces of the blades 82y on converging angles, as is seen in Fig. la, thereby minimizing vary as much as 20 in either direction.

Air is supplied to the plenum chamber 70 through a header 86 andfthree conduits 88.A The air pressure in the plenum chamber 70 is maintained in the range of l to 7 p. s. i. by a high capacity low pressure air pump such as a rotary lope pump (not shown) connected to the header v86.

The large volume of air from the air knife 16 presents several problems in its control and dispersion. When a workpiece is beneath the air knife the air stream spreads and goes toward thefront and rear of the machine.. The air going toward the front of the machine removes the excess of seasoning compound on the workpiece returning it to the sump 18, the bales 66, 68 preventing it from interfering with the action of the nozzles 14. The air going toward the rear of the machine and toward the sides of the machine has no ill effect. However, when there is no workpiece beneath the air knife it is necessary that the air not flow into the sump 18 and it is also necessary that it not flow toward the rear of the machine and interfere with a workpiece which is being discharged. Additionally, care must be taken that the seasoning material not be `blown about by this air. lems, I have provided a tray 90 the forward edge .of which is tangential with the air stream of the air knife `16 and which has a lid 91 (Fig. 4) spaced from said forward edge a distance slightly greater than the width of the `airstream. The air stream thus enters lthe box `and can go only toward the sides of the machine where it can be discharged and dissipated in the most advantageous manner through openings 92. A plate 94 extends from .the .tray i 90 and provides convenient means for -the return of seasoning material to the sump 18. It is tobe noted thatthe mentioned edge of the tray 90 also provides support means for the conveyor 12 so thatA workpieces will be maintained .at a proper distance from the air knife 16.

In the operation of the present device the motorMpand the kpump P 4operate continuously and .may be `controlled conveniently rfrom a switch box SB mounted onone leg.

The air knife 16 is shown normal to the Y conveyorlZ; this relationship is not critical and could` As a solution to these various prob-l 38. Workpieces are spread out upon the infeed conveyor and carried thereby to the main conveyor 12. The speed differential-between the two conveyors assures that a workpiece Will not become wrinkled as it is transferred from the conveyor 10 to the conveyor 12. The workpiece is then carried to the solid curtain of seasoning material produced by the nozzles 14 and the leather surface is thoroughly wetted by the seasoning compound and the pigment rubbed into the grain surface by the force of spray. It will be noted that the infeed conveyor 10 maintains the trailing portion of the workpiece above the conveyor 12 so that as seasoning material ows toward the forward portion of the machine it cannot spill over the roll 20 as it would normally do if the conveyor 10 were not provided. After having been thoroughly covered by an excess of seasoning material, the workpiece is then conveyed toward the air knife 16. It will be noted that the work bearing run of the conveyor 12 slopes away from the air knife at its approaching side and thus a good portion of the excess seasoning material will drain from the leather surface so that the air knife itself has to remove only a relatively small quantity of seasoning. At any event the air knife effectively removes the excess seasoning material so that a thin uniform coating is applied to the workpiece. As has been mentioned above, leather workpieces are far from being uniform, especially in regard to thickness and adaptability to lying even or flat. It will be noted that one of the primary advantages of the use of the air knife is that the intensity or pressure of the air stream remains substantially constant through a substantial distance. Thus, even though workpieces have heightwise variations in their surface they will be stripped to the same degree and an even coating will result. Of further advantage is that the air stream forces the workpiece downwardly against the upper edge of the tray 90 which acts as a backup member. Thus not only may the lair stream accommodate heightwise variations but it minimizes such variations by attening the workpiece as it is carried beneath it.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. A seasoning machine comprising an openwork conveyor which permits the passage of air therethrough, an infeed conveyor moving at a lower rate of speed than said rst named conveyor and extending above said rst named conveyor for retarding and maintaining the trailing edge of a workpiece above said first named conveyor until it is deposited thereon, means for applying an excess of seasoning compound to individual workpieces carried by said rst named conveyor, and an air knife extending widthwise of said iirst named conveyor for removing the excess of seasoning compound from each workpiece thereby leaving a thin uniform coating thereon.

2. A seasoning machine comprising an openwork conveyor which permits the passage of air therethrough, said conveyor having an upper work carrying run, means for applying an excess of seasoning compound to individual workpieces carried by said conveyor, an air knife extending widthwise of said conveyor for removing the excess of seasoning compound from each workpiece, a tray mounted beneath the upper run of said conveyor, said tray having a forward edge which is parallel to and adjacent the air stream of said air knife, and a lid covering said tray spaced from said edge a distance slightly greater than the width of said air stream, said tray having openings in its ends whereby the air from said air knife is dissipated toward the sides of the machine.

3. A seasoning machine comprising an openwork conveyor which permits the passage of air therethrough, means for applying an excess of seasoning compound to individual workpieces carried by said conveyor, said means including a series of flat spray nozzles mounted above said conveyor, a sump toward which said spray nozzles are directed, a deflection plate the upper surface of which is tangential to the stream of seasoning compound emitting from said nozzles, the lower surface of the plate entering the compound level in the snmp for directing the stream of compound into the sump with a minimum of turbulence, and an air knife extending across the width of said conveyor for removing the excess of seasoning compound from each workpiece thereby leaving a thin uniform coating thereon.

References Cited in the tile of this patent UNITED STATES PATENTS 200,078 McDonald Feb. 5, 1878 1,352,186 Flanagan Sept. 7, 1920 1,514,345 Salerno Nov. 4, 1924 1,673,686 Kremmling Nov. 13, 1926

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