US2949661A - Surfacing tool - Google Patents

Description

Aug. 23, 1960 H. J. CREDIT Filed Oct. 20, 1955 5 Sheets-Sheet l Fig.5

Aug. 23, 1960 H. J. CREDIT SURFACING TOOL Filed Oct. 20, 1955 3 SheetsSheet 2 SURFACING TOOL Harold John Credit, 39 ClintonSL, Avon, NY. Filed Get. 20, 1955, Ser. No. 541,686 1 Claim. (Cl. 29-79) This invention relates to a surfacing tool useful in finishing or altering the surface of various materials, such as wood, plastic, composition board, or even soft metal.

An object of the invention is the provision of a generally improved and more satisfactory surfacing tool.

Another object is the provision of an improved form of surfacing element which may be embodied either in a hand operated tool or in a power driven tool.

Still another object is the provision of a surfacing tool which is comparatively inexpensive, easy to manipulate, and highly satisfactory in giving a. smooth finishing surface on wood or a variety of other materials.

A further object is the provision of a surfacing tool so designed and constructed that the cutting blades may be readily renewed and replaced.

A still further object is the provision of a power driven surfacing'tool of relatively light, compact, and inexpensive design.

These and other desirable objects may be attained in the manner disclosed as an illustrative embodiment of the invention in the following description and in the accompanying drawings forming a part hereof, in which:

Fig. 1 is a side elevation of a surfacing tool constituting a hand operated embodiment of the present invention;

Fig. 2 is a bottom view of the same;

Fig. 3 is a fragmentary perspective view of the left end of the holding frame shown in Fig. 1;

Fig. 4 is a fragmentary perspective view of the right end of the holding frame;

Fig. 5 is a fragmentary horizontal section taken substantially on the line 5-5 of Fig. 1;

Fig. 6 is a fragmentary horizontal section through the right end of the surfacing unit removed from the holding 5 frame;

Fig. 7 is a view partly in elevation and partly in vertical section taken centrally through a first motor driven embodiment of the invention;

Fig. 8 is a bottom face or bottom plan view of the cutter head or surfacing head of Big. 7;

Fig. 9 is a horizontal section taken substantially on the line 9-9 of Fig. 7, showing the surfacing head mainly in top plan;

Fig. 10 is an enlarged vertical section through a fragment of the surfacing head, taken substantially on the line 10-10 of Fig. 9;

Fig. 11 is a bottom plan view of another form of surfacing head;

Fig. 12 is a similar view of still another form of surfacing head;

Pig. 13 is a fragmentary vertical section taken substantially on the line 13-13 of Fig. 12;

vFig. 14 is a view similar to Fig. 7, showing a second power driven embodiment of the invention, employing dual or twin surfacing heads; and

Patented Aug. 23, 1960 Fig. 15 is a bottom plan view of the construction shown in 'Fig. 14.

The same reference numerals throughout the several views indicate the same parts.

Referring first to the simple hand-operated form of the invention disclosedin. Figs. 1-6, this form of the invention provides a surfacing tool the effective operating surface of which is formed by a plurality of blades extending in different non-parallel directions, the edges of the various blades lying in a common plane and being provided with small saw teeth, similar to the teeth of a hacksaw blade, for example. The implements may have any suitable number such as three blades, 21, 23, and 25 extending substantially parallel, to each other and spaced laterally from each other, together with an intermediate blade. 27 arranged in zigzag relation between the blades 21 and 23, and a second intermediate blade section 29 arranged insimilar zigzag relation between the blades 23 and 25. The members 27 and 29 may each be made ofa single piece bent to the zigzag formation and weldled or riveted to the respective blades 21, 23, and 25 at the points where they touch, or of course may be made of separate straight pieces of shorter length, each separately Welded or riveted at both ends to the respective longitudinal blades.

In any event, the various blades 21, 23, 25, 27, and 29 are provided on one or both edges with small or fine saw teeth like the teeth of a relatively fine hacksaw blade (e.g., 18 teeth to the inch or 24 teeth to the inch) and the respective blades are assembled in such relation to each other that corresponding edges lie in a common plane, so that the tips of all the saw teeth on the entire group of blades will simultaneously touch a plane surface if laid thereon. Although it is within the scope. of the invention to provide only one edge of each blade with saw teeth, yet it is preferred that both of the opposite edges be toot'hed, so that when one face of the implement becomesdulled after repeated surfacing operations, it may be turned over and the other face may be used.

For holding this implement and operating it, a convenient frame is provided, in the form of a relatively rigid longitudinal strut member 31, preferably of angu lar cross section as seen: in Fig. 3, to give it greater rigidity. At one end of the member 31 abracket 33 is secured by a screw or rivet 35, this bracket having depending ears on opposite sides of the strut 31, provided with hook notches 37, the ears being spaced laterally just sufliciently to fit snugly within the outside toothed members 21 and 25 as seen at the left end of Fig. 2. The notches "37 engage spacing sleeves 39 surrounding a cross pin or cross bolt 41 which extends transversely through the blades 21 to 29, inclusive, at one end of the composite blade structure, the details being seen in Fig. 6, the same cross pin and spacing sleeve construction being used at both ends of the blade structure.

At the opposite end of the strut 31 there are angle brackets. 45 secured by bolts or screws 47 to the strut member and having ends bent downwardly perpendicular to the length of the strut, and provided with an opening through which extends loosely a screw 49, the opening being of sufficient size so the screw threads may. slide longitudinally through the opening. The head 51 of the bolt or screw is retained within a U-shaped yoke member 55 as seen in Fig. 5, the. parallel sides of which have hook notches 57 (see also Fig. 4) for engaging over the spacing sleeves 39 of the cross pin at the opposite end of the blade structure from the end held by the bracket 33. A suitable handle 59 has an axial threaded bore screwed onto the threaded shank 49; When the cross pin at one end of the blade structure is hooked I into the hooks 37 of the bracket 33 at one end of the rigid frame, and the cross pin at the opposite end of the blade structure is hooked into the hooks 57 of the member 55, then the handle '59 is turned to act as a nut to pull on the screw 49 and to produce the desired degree of tension on the blade structure.

When the blade structure has been properly tensioned (in much the same way that a hacksaw blade is tensioned in a conventional hacksaw frame) the implement is ready to use. It is grasped in one hand by the handle 59, the other hand of the user being placed, if desired, on the far end of the frame, and the implement is rubbed back and forth on the piece of wood or other surface to be treated, with the teeth of the several blades collectively resting on the surface to be treated.

It might be thought at first glance that this implement would make actual cuts or grooves in the surface to be treated. However, actual use of the invention in practice shows that this is not so. If the implement be pressed relatively lightly but firmly on the surface to be treated, and be rubbed gently but firmly over the surface (either with a straight push and pull motion or with a somewhat rotary motion) it is found in practice that this implement will dress down the surface being treated to a smooth and fine finish, Without leaving grooves or cuts, the finished surface looking much as though it had been sanded with sandpaper. However, this implement works much faster than sandpaper, and thus can be used more quickly to dress down or remove a given thickness of the work to be treated. It is very useful in removing a thick layer of old varnish or paint, for example, but may also be used for actually removing some of the wood or other substance of the main body being operated upon.

The invention may also be embodied in motor driven apparatus, in addition to the hand operated implement as above described. Referring now to the motor driven form illustrated in Figs. 71(), there is a main casing or housing 71, conveniently of approximately upright cylindrical form, and made for example of a casting of light metal such as aluminum. On opposite sides it has convenient handles 73 for easy grasping and manipulation, which handles may be cast integrally on the body 71 or separately secured thereto by screws 75. A horizontal partition 77 intermediate the ends of the body furnishes support for the ball bearings 79 and 81 (the latter held in place by a retaining plate 82) which mount a vertical shaft 83, the top end of which is coupled at 85 to the power shaft 87 of an electric motor (not shown) located within the motor housing 89 secured to the top plate 91 which is bolted to the top edges of the main housing 71. When the electric motor is operated, it thus rotates the vertical shaft 83 at a. high speed.

Extending axially in the lower part of the vertical shaft 83 are two bores, a lower smooth bore 95 open at the bottom end of the shaft, and an upper and smaller threaded bore 97 in which is threaded the shank of an adjusting screw 99. The smooth bore 95 receives the smooth upper part of the shank 101 of the surfacing head and allows this shank to enter snugly into the bore 95 to an axial extent permitted by the position of the adjusting screw 99, until the shank abuts against the head of .the adjusting screw. The shank of the surfacing head is held against movement in the shaft 83 by means of a set screw 105, accessible through a lateral opening in the wall 71. Preferably the shank 101 is tubular, having a central bore 107 through which a small screwdriver may be inserted to engage the slotted head of the adjusting screw 99 so as to adjust this screw to vary the axial position of the surfacing head (when the set screw 105 is loosened, of course).

The surfacing head itself comprises, in addition to the shank 101, a main frame or head structure of somewhat spider formation, firmly fastened to the shank 101, the preferred construction being shown in Figs. 7l0. The structure includes, for example, an approximately cylindrical circular marginal flange 111 integral with a diametrical cross piece or rib 113 which is fastened by riveting, welding, of the like to the lower end of the shank 101.

The cylindrical portion 111 has thickened sections provided with vertical slots or grooves 115 for receiving the ends of any desired number of sawtooth blades 117. The slots 1 15 do not go all the way to the bottom of the thickened sections, but stop short thereof, so as to leave a radially inwardly extending abutment flange or shoulder 119 at the lower edge of the cylindrical member 111 (see Fig. 10) to serve as a support to limit downward movement of the blades 117, which are inserted in the grooves 115 from the top. The blades are held firmly in their respective slots 115, pressed downwardly tightly against the abutment 119, by means of resilient pads 123 formed of chunks of rubber or other suitable resilient material, which lie across the top edges of the blades 117 and are pressed firmly downwardly onto the blades by a resilient presser arm 125 of suitable metal such as spring steel, extending diametrically across the surfacing head in a direction crosswise of the blades 117, and pressed downwardly against a lower not 127 by' an upper nut 129 screwed onto a threaded part of the shank 101 lying below the smooth part thereof which enters the bore 95. The ends of the spring 125 are notched at 131 to receive short vertical ribs 133 formed on the inner face of the frame member 111, to hold the spring 125 against turning when the nut 1 29 is being tightened or loosened.

In the form of surfacing head shown in Figs. 8 and 9, there are two groups of blades 117, each group containing three blades, the groups being on opposite sides of the central shank 101 and both groups being parallel to each other, while the blades in each group are parallel to themselves. This is the construction which is at present preferred, but is not the only possible construction. In the modified form shown in Fig. 11, for example, the outer cylindrical part 111a of the frame is supported from the shank 101 by means of a three-armed hub or spider 113a, and the blades 117a are here arranged in three groups instead of two, each group comprising three blades parallel to each other, the blades of each group being at substantially 60 to the blades of the other groups, as seen. The notches, supporting flanges, etc., in this form of surfacing head are the same as before, but of course three resilient pads will be used instead of two, to overlie the three groups of blades, and the retaining spring 125 will have three arms to overlie the three resilient pads, instead of only two arms. Otherwise the parts are the same.

In Figs. 12 and 13 there is shown still another variation of the surfacing head, in which the blades are not straight but curved. Here, the shank 101 is the same as before, but the rest of the main body or frame of the surfacing head preferably comp ses a stamped sheet metal body extending radially outwardly from the central shank 101 as seen at 141 (Fig. 13), then axially upwardly at 143, radially outwardly' again at 145, and axially downwardly at 147 to provide a marginal flange extending circumferentially around the surfacing head. In the recess or space between the flanges .143 and 147 the blades 149 are mounted, of any desired number, three such blades being here shown in Fig. 12, the blades each being curved as shown in the drawings so that they occupy a somewhat spiral position with the inner end of each blade secured to the flange 143 and the outer end secured to the flange 147. In the forms shown in Figs. 8-11, each blade 117 is preferably double edged, as seen especially in Fig. 10, so that when the teeth of one blade are worn down to an undesirable extent, the nut 129 may be loosened to remove the sp'rmg presser bar .125 and the pads 123, whereupon the various blades may be lifted out of their individual notches, turned upside down, and put back in the notches with the new sharp teeth downwardly. Then the pads 123 and the arm 125 are replaced and the nut 129 is tightened, of course. In the spiral form of construction shown in Figs. 12 and 13, the blades 149 may be arranged in a removable manner if desired, in which case they may be doubled edges, with teeth at both edges. Preferably, however, the blades in this spiral form of construction are permanently mounted in the frame, as for example by being welded at their ends to the respective flanges 143 and 147.

It will be noted that in all of the forms of surfacing heads illustrated for use with this motor driven machine, the blades do not extend in the circular direction of rotation, but at an angle to the circle of rotation. Thus the blades may be described as being, broadly, non-circular blades, or as rotating blades which extend in noncircular directions with respect to their axis of rotation. Each blade, during use on the work surface which is being operated upon, has a component of motion which is transverse to the lengthwise direction of the blade, as well as a component of motion parallel to the length wise direction of the blade. Because of this transverse component of motion, the blades do not cut a groove or kerf in the work being operated upon, but perform a surfacing operation on such work, just as was the case in the hand operated or manual form of construction disclosed in Figs. 1-6, where certain of the blades, being in non-parallel relation to each other, will always have a component of motion transverse to the length of the blade, no matter in what direction the manually operated tool is moved over the surface of the work being operated upon. It may be said, generically, that in all forms of the surfacing implement (both motor driven and hand operated) there are a plurality of blades with toothed edges engaging the work, at least some of the blades extending in directions which are non-parallel to the direction of movement of the blades relative to the work, or in directions such that the movement of the blade relative to the work has a component transverse to the length of the blade.

In this motor driven form of construction shown in Figs. 713, the lower edge of the main casing or housing 71 is preferably provided with a widened or thickened flange 151 having a bottom surface of sufficient area to slide easily over the work without digging into it or gouging, and thus provides a supporting shoe or foot for resting upon the work and for determining the depth to which the rotating surfacing head grinds into and dresses down the work, as the machine is advanced bit by bit across the surface of the work. The amount of dressing down which is accomplished at each passage of the machine over a given area of the work, is determined by the extent to which the lower edges of the toothed blades project below the bottom surfaces of the foot or shoe flanges 151, and this in turn is determined by the adjustment of the screw 99 which controls the elevation of the shank 101 and the entire surfacing head or tool, with respect to the main shaft 83 and the main frame 71 of the mechanism. The lower edges of the flanges 151 are provided with transverse grooves 153 at spaced intervals, for easy exit of the powder or dust created by operation of the machine.

In Figs. 14 and 15 there is shown a motor driven surfacing mechanism similar in general to that disclosed in Fig. 7, but having two rotating surfacing heads instead of a single head, the two heads being driven in synchronism with each other and being of elliptical or other non-circular shape so that the areas swept by the two heads overlap each other.

The machine in this embodiment comprises an upright main frame 171 having convenient operating handles 173 on opposite sides, fastened to the side walls of the upright headset 6 frame 171 by screws 175. The cross partition 177 car ries ball bearings 179 and 181 (the latter held in place by the removable retainer plate 182) for the main vertical shaft 183 which has a diametrical slot through its upper end to receive a driving bit 185 on the lower end of the power shaft 187 of an electric motor Within the casing 189, supported on the top plate 191 of the main housing. Similar ball bearings 178 and 180 in the horizontal partition 177 serve to support a secondary vertical shaft 184 parallel to and offset laterally from the shaft 183, and driven from the latter in synchronism therewith by spur gears 186 and 188 meshing with each other and keyed or otherwise fixed respectively to the shafts 183 and 184.

The lower end of each of the shafts 183 and 184 is constructed the same way as the lower end of the shaft 83 in the earlier embodiment. That is, each shaft has a large and smooth axial bore 195, a smaller threaded bore 197, and an adjusting screw 199 threaded into the latter, corresponding in arrangement, purpose, and function to the respective parts 95, 97, and 99 in the embodiment previously disclosed. As before, the shank 201 of the surfacing head is thrust into the smooth bore to an extent determined by the position of the adjusting screw 199, and is held therein to rotate with its shaft by means of the set screw 205 corresponding to the set screw 105 of the previous embodiment, which set screw is accessible through a lateral opening 206 in the'casing 171, while the adjusting screw 199 is accessible through the axial bore 207.

The surfacing heads used with this twin shaft form of construction may take various forms, just as was the case with the single shaft construction previously disclosed. If desired, two identical heads of circular outline may be used, of sufliciently small diameter so that when mounted on the respective shafts 183 and 184, they will not quite touch each other and will not interfere with each other. If such circular heads are used, they may take any of the forms more specifically disclosed in Figs. 713.

It is preferred, however, when using the twin shaft form of driving mechanism, to use non-circular heads oriented in such a way with respect to each other that the areas swept over or operated upon by the two heads will overlap each other, yet the two heads will not interfere with or touch each other. A convenient arrangement is to use the elliptical heads shown in Fig. 15. As will be noted from Fig. 15, the heads are mounted in their respective shafts in such manner that when the long elliptical axis of one head points towards the shaft of the second head, the short elliptical axis of the second head points toward the shaft of the first head. As the heads rotate at equal speeds in opposite directions, the heads will not touch each other, but the eccentricity of each ellipse is suflicient so that the areas covered thereby will overlap each other. Assuming, for example, that the heads (when viewed from the bottom as in Fig. 15) rotate in the direction of the arrows, with the left hand head rotating clockwise and the right hand head rotating counterclockwise, it is seen that by the time the right hand head has moved to the left, so that its long axis points toward the left shaft, the left head will at the same time have moved 90 to the right so that its short axis now points toward the right hand shaft. Thus in all positions, there will be no contact or interference of one head with the other.

Except for the elliptical outline in place of a circular outline, the heads may be of the same construction as previously described, for example, in connection with Figs. 7-10. As before, the blades 217 may be arranged in two groups of three blades each, the blades of each group being parallel to each other, and the two groups also being parallel. The ends of the blades are held down against the bottom flanges 219 of the head frame 211, by overlying pressure pads 227 of rubber or the like,

7 which in turn are pressed downwardly by the spring member 225 held in place by the nuts 229 and having notched ends engaging the ribs 233 to prevent accidental turning of the spring member when the nut is tightened or loosened. It will be recognized that the parts of the elliptical heads in Figs. 13 and 14 are, except for the elliptical outline, the same as the corresponding parts of the circular head of Figs. 7-10, and are identified by the same reference numerals increased by one hundred, so that the present blades 217 of the elliptical embodiment correspond to the blades 117 of the previous circular embodiment, the spring 225 corresponds to the previous spring 125, and so on. The same numerical relationship is true also of the major parts of the housing and driving mechanism of Fig. 14 as compared with that of Fig. 7. It is thought that no further explanation of the construction and operation of the elliptical heads will be necessary.

The bottom of the side walls of the frame 171 in this embodiment is preferably provided with a thickened foot or shoe 251, corresponding to the foot or shoe 151 in the previous embodiment, and likewise having the grooves or notches 253 to enable easy escape of the powder or dust formed by the rotating heads during operation.

It is seen from the foregoing disclosure that the above mentioned objects of the invention are well fulfilled. It is to be understood that the foregoing disclosure is given by way of illustrative example only, rather than by way of limitation, and that without departing from the invention, the details may be varied Within the scope of the appended claim.

What is claimed is:

A surfacing head including a shank, a hollow frame secured to said shank, a plurality of elongated blades each having a multiplicity of pointed teeth along at least one edge of the blade, means for holding said blades in stationary position relative to said frame with the teeth on corresponding edges of all blades lying substantially in a common plane perpendicular to said shank, said 8 holding means including slots in said frame into which the ends of the blades are removably received, resilient pad means overlying and pressing against certain edges of the blades to hold them in their respective slots, and spring means overlying and exerting pressure against said pad means. I

References Cited in the file of this patent UNITED STATES PATENTS 67,618 Fisher Apr. 14, 1868 817,502 Mitchell Apr. 10, 1906 854,725 Devers May 28, 1907 943,102 Schleicher Dec. 14, 1909 1,011,916 Carlson Dec. 19, 1911 1,100,544 Densmore June 16, 1914 1,284,092 Gray Nov. 5, 1918 1,392,543 Watrous Oct. 4, 1921 1,394,564 Lindgren Oct. 25, 1921 1,410,350 Hawkins Mar. 21, 1922 1,551,854 Skinner Sept. 1, 1925 1,641,103 Small Aug. 30, 1927 1,652,915 Staehle Dec. 13, 1927 1,682,678 Kenan Aug. 28, 1928 2,015,220 Ha-rkin Sept. 24, 1935 2,066,741 Ripsch Jan. 5, 1937 2,079,995 Hodgkins May 11, 1937 2,103,377 Norton Dec. 28, 1937 2,306,470 Rush et al Dec. 29, 1942 2,395,158 Yandell Feb. 19, 1946 2,480,739 Johnson Aug. 30, 1949 2,615,482 Parovel Oct. 28, 1952 2,746,499 Greeley May 22, 1956 FOREIGN PATENTS 172,899 Great Britain Dec. 22, 1921 645,005 Great Britain Oct. 25, 1950 1,007,429 France Feb. 6, 1952 174,200 Austria Mar. 10, 1953

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