US2334960A - Molding sanding machine - Google Patents

Description

L. ROTH ET AL MOLDING SANDING MACHINE Nov. 23, 1943.

Filed Feb. 12 1941 2 Sheets-Sheet l Fig. 2.

INVENTORS Lou/s Qon/ ATTORNEY Nov. 23, 1943. ROTH ET AL 2,334,960

MOLDING SANDING MACHINE Filed Feb. 12, 1941 2 Sheets-Sheet 2 413 0 78 85 86 l P75 77 Fzg D Q -87 66*- p gJ Fig 7 Fig 61 INVENTORS ATTORN EY Patented Nov. 23, 1943 oFFlciz MOLDING SANDING MACHINE Louis Roth, Dubois, and John M. Schnaus, Jasper, Ind.

Application February 12, 1941, Serial No. 378,528

4 Claims. (Cl. 51-135) Our invention relates to sanding or abrasive machines of the belt type, in which the surfaced article to be smoothed or finished, is moved into contact with an abrasive web or belt traveling at relatively high operating speed, and especially to a type of machine that has been particularly developed for finishing molding or the omamental edge faces of boards, such as provided for edges of table tops, pilasters of cabinets, or the beaded contours of other objects, especially those made of wood for furniture and construction material, referred to sometimes herein generally as molding.

A main object of this invention is to provide mechanical means for producing a high grade finish by the use of a sanding belt operated at a high speed equal to carefully execute hand operations, on moldings, especially of complicated design, thus producing a high grade finish at low cost.

Another main object of this invention is to provide means for successfully operating, at a high rate of speed over a dissymmetrical contoured sanding head, a sanding belt formed by lapping and cementing the ends of a strip of sand-faced cloth or paper to form a secure joint. It should be noted that the thickness of the sanding belt is uniform throughout its length except at the joint formed by the overlapped secured ends and that since it is impracticable to effect uniform contact between the molding and the sanding belt only when the uniform portion of the beltis passing over the sanding head, the lap joint portion, at times causes difliculties as it passes between the head and molding when such a belt is operated on the earlier types of molding sanding machine employing a sanding belt operating over a sanding head shaped for completely sand finishing dissymmetrical molding during a single operation or passage of the molding over the said belt.

Another object of this invention is to provide a sanding head having portions, either rims or 1011. gitudinal mid-sections, made of a yielding or resilient material, which material will yield and absorb pronounced irregularities in the face of the molding and the joint in the belt or a combination thereof so as to impart a practically uniform travel to the belt and produce a substantially uniform surface on the molding.

It has been found impractical, if not impossible to machine sand finish the bottom portions of deep or narrow grooves sunk in molding with a sanding belt traveling over a formed wheel or head made entirely of a resilient material, since the pressure required to force the belt into said grooves would collapse the ridge or projecting portions of the head, consequently the abrasive material would not contact the bottom of the grooves. Likewise, for manufacturing operation, the use of a head made entirely of solid material for forcin a sanding belt into deep or narrow grooves have proven unsuccessful by reason of the absence of compensating means for irregularities in the sand belt when deformed by the head to contact the full surface of the molding or to compensate for ever present irregularities in the molding as prepared by the shaper. Therefore, another object of my invention is to provide a head having a portion of the face, tread or rim thereof constructed of sufficiently resilient material to compensate for irregularities in the molding and/or imperfections between the head and molding to produce smooth operation of the belt and enough rigid material to force the belt into the grooves sunk in the molding.

During our early experimental and development work, for successfully sanding molding on a commercial basis by a sanding belt operated over a sanding head, even after we had conceived and developed certain phases of our resilient sanding heads, only certain shallow" types of moldings could be processed and these were of a type having strips with sunken and projecting portions with balanced faces, which faces conformed to the sanding head having contours that averaged into a generally cylindrical form. By balanced face it is meant a type of molding having a contour conforming to a sanding head that would place a substantially uniform lateral tension on and generally equalize the deformation of the sanding belt while it traveled between the molding and said head. Therefore, a further object of our invention consists of providing means for operating a sanding belt over a sanding head having contours arranged in a generally conical formation for finishing the whole face of a molding in one operation, by diametrical engagement thereof with the sanding head in a patrix-matrix relation.

Referring to the drawings:

Figure 1 is a stop plan view of our abrasive machine.

Figure 2 is an end elevation of the machine without the sanding belt or the complete equiprFn ient1 of pulleys over which it is shown trained in Figure 3 is an end elevation of the work table, on an enlarged scale.

Figure 4 is a side elevation of the auxiliary idler forv the sand belt, on an enlarged scale.

Figure 5 is an elevation of a sanding head of a form employed to finish the type of molding shown in sectional elevation disposed against the top of the work table.

Figure 6 is an elevation in section of a sanding head of a. forln to finish the type of molding also shown in section and disposed on the work table.

Figure 7 is an elevation of one form of sand belt driving pulley used in combination with the sanding head shown in Figure 8 in elevation to produce the form of molding shown in Figure 9 in sectional elevation.

Referring to the drawings in detail, the frame of the sanding machine is designated generally by numeral ID, the top ll hinge-jointed to the frame at l2 and adjustable by means of rack l3 pivoted to the top at I3A and in mesh with pinions [4, keyed to the ends of shaft l5 journaled to the frame at l6 and on which shaft is also keyed a hand wheel l1 for rotating the shaft and gear for tilting the table top and the apparatus mounted thereon to any desired angle. Thus the table top and the equipment attached thereto can be set at any location from the full line to the broken line position.

Numeral 18A designates a motor having a base l9 slidably mounted on bracket 20, which is in turn secured to the bottom side of the top. A hand wheel and screw 2| are provided for adjusting the motor axially, the shaft I8 thereof and pulley 22. Also carried by the table top is idler pulley 23 journaled on a shaft projecting from bracket 24, which is slidably mounted on guide rods 25 horizontally disposed and secured to the edge of the table by means of bolts 26, A tension spring is disposed between the bracket and plate 21 for applying a tensloning force to, sanding belt 30.

Numeral 3i designates a sanding head rotatively mounted on shaft 32 carried by bracket 33' which is slidably mounted on arm 34, said arm is secured to the top of table by bolts 35 extending through slots 34A to provide lateral adjustment for the sanding head. 34B designates a hand wheel and screw for longitudinally adjusting the sanding head in terms of the axis thereof.

Also mounted on the table top is a second or auxiliary idler pulley 36 pivotally mounted on axially adjustable shaft 31, which is hinge-jointed at 38 to base 39 and adjustable by screws 40 threaded into top I I and disposed in slot 4| to provide lateral adjustment of the base. This idler pulley 36 is vertically adjustable by means of adjustable collars 4| which are secured onto shaft 31 and provide for locating the pulley at any selected height. Flanges 36A are spaced in terms of the width of a given sand belt in order that they can definitely guide and maintain it in a fixed course established by pulley 22 and head 3|, when the sand belt is idly traveling thereover and against lateral travel due to forces resulting from an unbalanced load on the belt incident to using only a part of face of the belt when sanding certain types of molding and that the load on the belt shifts from a balanced state throughout the width thereof to an unbalanced condition as when a lateral section of the belt is doing more work than an adjacent section.

The sand belt 30 travels in the direction indicated by the arrow, as shown in Figure 1, is trained over the drive pulley 22, idler pulley 23, sanding head 3! and idler pulley 36, with the latbe: adjusted to not only guide but deflect the sand belt from a normally straight line between pulley 22 and the sanding head. It should be noted that these adjustments for the pulleys and head are independent of one another and organized so that the sand belt can be shifted vertically, in terms of the table top, so as to change the portion of the belt in terms of the contours of the sanding head, as mentioned above. This feature is of particular service after a longitudinal streak has been developed in the sand bearing area from excessive wear, thus a new section or one having a less worn surface can be substituted for the worn streak without replacing the entire belt. The axial adjustment of idler 36 is of particular service when a dissymmetrical molding is under treatment and it is necessary to coax" the belt into a position not normal to or controllable by the drive pulley or the sanding head.

On the front of frame l0, an auxiliary frame 42 is attached for supporting a work table and adjusting apparatus therefor. Fixed on to this frame is a bracket 43 to which is slidably attached base 44, vertically adjustable by means of hand wheel and screw 45. An arcuate work table support 46 is rigidly attached to base 44 while pivotally mounted in the arcuate support is a pedestal 41 to which is hinge-jointed at 48! to subtable top base 48. By means of lever and screw 54, operatively associated with the arcuate table support, the pedestal can be released, oriented and secured at a desired location in terms of the sanding head. Hinge-jointed to base 48 at 48A are table shanks 49 rigid with the table top 50. Extended through the support 48 for free movement are bolts 5| encircled with springs 52, to provide resilience to the table top. Attached to the bottom end of pedestal 41 is arm 41A for supporting adjustable slotted brace 48C, hinge-jointed to 48 at 483. The adjustment of the work table is provided for locating it in terms of the tilted machine top I I, as shown in Figure 2, for supporting the molding while being subjected to sanding op erations, whether diectly in front of the sanding head when long strips of molding are being finished. When irregular pieces such as chair arms, table top edges are being sanded on the trailing side of the head, or adjacent this head and between it and the idler pulley 36, machine top H and the work table 50 are disposed substantially horizontal, as shown in Figure l, and the work table, shown in Figures 1 and 2, or another one of different proportions, is set at 01" about the location indicated by the dot-dash lines, the table having been oriented by means of the pivot mounting for pedestal 41. To effect this adjustment hand screw 54 is employed to release the table support'and then to re-clamp it after the table has been oriented to the desired location in terms of the work thereon and the grooves in the sanding head, to which reference has been made above.

The sanding head shown in Figure 5 consists of a plurality of generally cylindrical or discal sections 5s sa, inclusive, assembled withthe abutting faces thereof in juxtaposed relation and secured into the unit by a plurality of bolts 65 lodged in heads 56. In a preferred embodiment, the outside discs 56, referred to herein as these sections are composed of a soft or resilient material such as felt, rubber, cork, et cetera, and rigid materials such as wood fiber, micarta, metal, et cetera. In this particular head the generally concave and convex sections 51, 58, 59 and 60 are constructed of a firm felt and the intermediate sections 6|, 62 and 63 composed of hard wood fiber. The material selected for these sections and the arrangement thereof are for sand finishing the molding M shown in sectional elevation disposed on work table 58. Through the medium of adjustment and spring pressure, exerted by springs 52 or by means of adjustment alone in the event springs 52 have been made ineffective by bolts for certain types of work, table 58 is located so that the molding thereon will make a favorable engagement with the sand belt 30 (the sand belt is not shown in this Figure which belt is forced to conform to the organized contour of the sanding head. Since neither the head, the molding nor the sanding belt is geometrically perfect, springs 52 compensate for irregularitiesin any one or a combination of these elements. The sanding machine model selected for the drawings is dependent upon hand feeding the molding for processing; obviously machine or automatic feeding mechanism can be incorporated into the unit.

' The fiber sections apply heavier pressure to the sand belt than the adjacent broader felt faces, the latter serve to yieldingly apply the belt to the curve faces while the former forces strip sections of the belt into contact with the bottoms and adjacent areas of the molding. Thus, it will be perceived that slight irregularities of the belt, molding or face can be compensated for, whereas if the entire sanding head were of hard material, the irregularities would produce binding on, at least intermittent areas, which action would impair not only the life of a sanding belt, but produce an unsatisfactory surface on the molding.

The sanding head shown in sectional elevation in Figure 6, is primarily for finishing molding contacting the sand belt between the head and idler 36, the point of contact being adjacent the leaving side of the head. The central concave disk 84 being constructed of rubber and the abutting flanges 6586 comprised of fiber. These are lodged between heads 81-88 and are secured by bolts 68-18 and the entire head mounted on shaft 32. The sand belt employed for finishing molding II is forced into the deep grooves by the fiber flanges 8588, while the concave rubber section 64 embraces the convex section thereof with the belt interposed, as explained above in terms of Figure 5. Since the sand belt is under mild tension and is trained over normally crowned pulleys 22, 23, 36 and the sanding head shown in Figure 6, it will travel in a substantially fiat condition throughout the entire length thereof, except for a slight distortion at the head, until the molding is brought into sanding engagement with the belt and the latter is forced to conform to the shape of the molding when the said distortion will be more pronounced. Incidental to this distortion the width of the belt is shortened by reason of it being forced from a straight line, thus, the belt at the time of passing between the head and the molding is narrower than just before or just after this stage of the operation. This lateral tension of the belt is relied upon to yieldingly force it against the areas 12 of the molding and it is not pressed against this surface by the head as will be noted from the tapered depressed faces of 81a68a of end sections 81-88. These sections are of sufliciently small diameter to prevent said faces from pressing the belt into contact with the molding.

The dissymmetrical drive pulley shown in Figure 7, designated generally as P, and the dissymmetrical sanding head shown, designated generally as H, in Figure 8, are substituted, respective- 1y, for pulley 22 and head 8| in Figure 1 for finishing dissymmetrical molding 18 shown in Figure 9. With the assistance of flanges IL-ll of pulley P and flanges 18-88 of head H and idler pulleys 28-88, sanding belt 88 of a width just sumcient to engage face 18, of the pulley and face 18 of the head, can be driven at a satisfactorily high rate of speed and produce molding I8 as a regular commercial product. It should be noted that the configuration of each of said faces is generally of a truncated cone structure and that one is disposed conversely to the other. Through this arrangement the belt is maintained in a substantial balance as to linear tension.

Sanding head H may be composed of fiber or the like for discal sections 88, 8|, 82 and felt, or the like sections 83, 84, 88, 88 to perform the functions explained in terms of the similar structures shown in Figures 5 and 6.

v belt grooves 81, 88 are formed, respectively, in the flanges of pulley P and head H to provide an auxiliary means for driving the head from the motor I8A to provide means for forming the head without removing and transferring it to a lathe. This feature is of particular service after a long production run of molding and the shaperv or sticker cutter knives have been somewhat changed during resharpening. A short piece of the molding made from the resharpened cutter knife is repeatedly coated with a lacquer surface and coated with an abrasive to form a tool" for reshaping the head while being driven by the V belt and motor I8A. Thus the head can be made to exactly conform to the molding or, in the event operating conditions are desired, as explained. in connection with Figure 6, certain longitudinal areas can be built up in excess of adjacent ones to form the desired clearances. V belt grooves are shown in the flanges of head 8| and pulley 22, but not designated by numerals.

The foregoing enumeration of fundamental principles and effects produced by the apparatus selected for disclosing this invention does not embrace all of the practical applications and modifications, consequently, other forms and functions will become evident as the field of use of the apparatus is varied and extended, therefore, we wish to be limited only by the claims appearing herein:

We claim:

1. In a unitary sanding head for finishing molding having projecting and sunk surfaces during one passage of the molding over the head, said head having projecting and sunk surfaces, the

'ombination of a series of resilient and rigid discs alternately disposed and secured into a unit with the peripheries of the rigid discs projecting beyond the peripheries of the resilient discs constituting the face of the sanding head, said head having flanges of rigid material projecting beyond the peripheries of the resilient discs.

2. A laminated sanding head for use in combination with a sanding belt traveling thereover, comprising discs of varying diameters, the discs of lesser diameter being composed of yielding material, and the discs of the greater diameter, having rigid characteristics, the several discs arranged in a series with the abutting peripherial edges of the juxtaposed discs merging in register,

one with the other.

3. In an abrasive machine for finishing the body of molding having strips, sunk and "projecting, comprising; an abrasive endless belt trained over a sanding head and a driving pulley for propelling the belt; said head having a rim of resilient material in circumferentially depressed grooved table and applying pressure to the moldingwhile being finished; said head having a. rim of resilent material in circumferentially depressed grooved form for receiving and shaping the sand belt to conform with the projecting areas of the molding; said head having a projecting circumferential rim of rigid material for forcing the sand belt to conform to the sunk strips of the molding.

LOUIS ROTH. JOHN M. SCHNAUS.

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