US 3846060 A
A trowelling tool for use in smoothing and shaping mastic caulking compounds comprising a body member having aligning and bearing surfaces at its sides to rest upon and be guided by right angularly disposed wall surfaces contiguous with a corner joint or juncture being caulked. The body spans a rough laid bead of caulk and a trailing finger packs and trowels the bead clearly defining the edges of the bead, and laterally displaces excess caulk for easy removal.
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Description (OCR text may contain errors)
United States Patent [1 1 Otis [451 Nov. 5, 1974 TROWELLING TOOL  Inventor: George A. Otis, 715 E. Los Angeles Dr., Vista, Calif. 92083  Filed: May 29, 1973  Appl. No.: 364,373
 Int. Cl E04f 21/32  Field of Search 15/104 S, 105.5, 235.3,
 References Cited UNlTED STATES PATENTS 2,247,603 7/1941 Christman 425/458' 2,420,062 5/1947 Amos 425/87 3,087,654 4/1963 Moore 425/458 11/1964 Gallagher 15/2353 X 7/1973 Krause l5/235.7
Primary Examiner-Daniel Blum  ABSTRACT A trowelling tool for use in smoothing and shaping mastic caulking compounds comprising a body member having aligning and bearing surfaces at its sides to rest upon and be guided by right angularly disposed wall surfaces contiguous with a comer joint or juncture being caulked. The body spans a rough laid bead of caulk and a trailing finger packs and trowels the bead clearly defining the edges of the bead, and laterally displaces excess caulk for easy removal.
l0 Claims, 9 Drawing Figures TROWELLING TOOL BACKGROUND OF THE INVENTION In the application of a caulking bead at the juncture of an angularly disposed pair of walls considerable difficulty is encountered by the craftsman as well as the unskilled in shaping, packing and trowelling the mastic caulking compounds to form a straight and clearly defined bead. The problem largely arises due to the fact the initial extrusion of caulk as from a collapsible tube or a caulking gun is irregular in shape and generally involves an excess of caulk. The removal of the excess by wiping or scooping with a putty knife or similar tool is often accompanied by disruption of the desired applied bead in the juncture being caulked. Various kinds of corner-finishing tools are known from US. Pats. Nos. 2,824,443; 2,903,739; 2,193,390; 2,247,603; and 3,087,654. These however have not been found capable of trowelling a bead in a right-angle corner and displacing during the trowelling any excess caulk to locations where it can be easily removed, it being the primary object of this invention to do so. Another object of this invention has been the provision of a tool that may be accurately aligned between a pair of right-angle surfaces and in movement longitudinal of the juncture therebetween be smoothly guided and supported thereby. Still another object is the provision in such a trowelling tool of resilient scraping and trowelling means whereby pressure is applied to the mastic caulk during trowelling to insure filling and to expell entrapped air or gas bubbles. Other objects and advantages will be apparent during the following description of a preferred embodiment of this invention.
DESCRIPTION OF THE DRAWINGS.
FIG. 1 shows in perspective this trowelling tool in use in the formation of a bead of caulking material;
FIG. 2 is a perspective view of the tool;
FIG. 3 is a front elevation view;
FIG. 4 is a side elevation view;
FIG. 5 is a plan view of the underside; and
FIGS. 6, 7, 8 and 9 are enlarged frontal views of various packing and trowelling tips of the operating finger of the tool.
DESCRIPTION OF THE PREFERRED EMBODIMENT In the accompanying drawings is shown in full detail the preferred embodiment of this trowelling tool, which is fully capable of attaining the objects and providing the advantages stated above. It is to be understood that this is primarily merely illustrative and that no limitations are intended to the details of construction or design other than as defined by the subjoined claims.
Referring to FIG. 2 the trowelling tool of this invention is shown to comprise body member 10 which is plate-like and of a size to be easily grasped and manipulated by a persons fingers. The plate 12 is roughly rectangular and thin, being narrowed in both directions at the waist as at 14 to facilitate grasping when the plate is placed in spanning relation to the angularly disposed surfaces l6, l6 and in overlying spaced-apart relation to a roughly extruded bead of plastic caulking material 18. Each of the several corners of plate 12 has an angular bearing surface 20. The bearing surfaces 20, on one side of plate 12 are arranged at right angles to the aligning and bearing surfaces 20, 20 on the opposite side, and each is sufficiently long to bridge tile grout, and they are spaced apart so as to preclude bouncing or jarring which could occur if their span were the same as, say, the length of a piece of tile. In a right angle wall juncture as shown the aligning surfaces are arranged so that plate 12 will be disposed normal or aligned perpendicular to plane P-P (see FIG. 3) which bisects the angle formed by wall surfaces l6, 16.
To increase the guiding and aligning effect of bearing surfaces 20, legs 22 extend from the underside of plate 12. The outer surfaces 24 of legs 22 are coplanar with surfaces 20.
From the foregoing it will be seen that the tool has a rigid plate-like body member adapted for easy grasping and manipulation by the fingers and that, when brought to bear on a pair of angular surfaces 16, will be centered and aligned as it is moved longitudinally along said juncture being smoothly guided in such movement by the surfaces l6, l6.
Trowelling finger-30 trails from body member 12 and extends angularly downward and rearward into the juncture as best seen in FIG. 1. Finger 30 comprises the root portion 32 and the tongue 34. The terminal edge 36 of tongue 34 extends across the juncture being caulked and functions together with the underside of tongue 34 to pack and trowel the plastic caulking material. In FIG. 6 the edge 36 is straight and when used the trowelled surface resulting is normal to plane P-P. The terminal edge 38 of FIG. 7 is concave and, when used, produces a convex surface on the trowelled bead. The terminal edge 39 of FIG. 8 is convex, and, when used, produces a concave surface on the trowelled bead. The terminal edge 47 of FIG. 9 is flat, or concave, or convex, and is offset vertically (stepped upward slightly) at each end. This is done to obtain sharp and well defined bead edges without the irregularities associated with feathered edges. The height of step 49 is exaggerated in the drawing for clarity and, in practice, may be of the order of a few thousandths of an inch, for example, about 0.006 inch. The underside of tongue 34 contiguous with terminal edges 36 or 38 is preferably convex at 37 to provide tangency with the surface of the caulk as the tool moves thereover.
Contiguous with each end of terminal edge 36, 38, 39, or 47, the tongue 34 is provided with fairly sharp scraper edges 40, which operate to bear on and be guided by surface 16 in a stabilizing fashion and also to sweep or laterally displace excess caulking away from the bead 42 being formed from the initially placed material 18. The effective bearing plane of rscraper edge 40 and of body bearing surfaces 20 and leg outer surfaces 24 are coplanar on each side of body 10 and will be seen in FIG. 3. The lateral displacement of excess strips 44 in spaced apart relation to bead 42 permits their quick and easy removal. If one wishes to immediately remove the excess caulk as with a putty knife he may do so without messing up the very neat bead 42. Or he may allow the caulk to partially cure or set, in which case the excess strips 44 having appreciable strength, may be peeled off surfaces 16 with the fingers, it being common for many caulking compounds to acquire adequate tensile strength, while curing, to allow such peeling (since bond to a non-porous sub-strate is usually developed later in the curing process). The back sides of tapered tongue 34, contiguous with the scraper edges 40,40 are relieved as shown in FIGS. 2 and 3.
Many caulking materials tend to shrink upon curing. If a slightly concave final bead is desired the straight edge 36 or straight stepped edge 47 may be used. If a suitably flat exposed surface on the bead is desired one will use the concave edge 38 or concave stepped edge 47 to form a convex initial bead which will tend to shrink flat. For nonshrinking compounds, convex edge 39 or 47 may be used to achieve a concave surface on the bead.
Uses for this trowelling tool indoors are found around bathtubs, in the corners of shower stalls and bathtub enclosures, and above counters, behind sinks, around counter-top stoves, and along the edges of a floor/wall juncture and the like. External uses around house windows and doors and around boat cabins, hatches and the like will readily come to mind. The important consideration is that the joint to be caulked be in the in-- eluded angle between a pair of angularly disposed surfaces (not necessarily flat surfaces, not necessarily disposed at about 90).
in the preferred form of this trowelling tool it has been found most advantageous to mold the same of plastic, nylon being very satisfactory to insure long life and ruggedness and well within the economics of the matter. In a nylon tool the tongue 34 has a suitable resiliency permitting the tongue edges 40 to be presented and tightly pressed to surfaces 16 so that they are cleanly swept as excess caulk is displaced laterally from the bead 42, 46, 48, or 50. Other alterations and modifications occuring to those skilled in the pertinent art are intended to be covered by this patent.
What is claimed is:
1. A trowelling tool for mastic caulking compounds disposed bead-like at the juncture of a pair of right angularly arranged surfaces, comprising:
a body member to span between said surfaces in spaced-apart relation to caulking at said juncture;
said body member having a bearing surface on each side to be aligned with and be guided by one of said angularly arranged surfaces, said bearing surfaces lying in planes at right angles to each other and at a 45 angle to a plane bisecting said juncture;
a trowelling finger trailing from said body member and extending angularly toward and into trowelling relation with caulking at said juncture;
said finger, having a terminal edge to pack and trowel caulking between the surfaces at said juncture to form a bead, said finger having, contiguous with each end of said terminal edge, scraper means operable to bear on and be guided by the surfaces adjacent said juncture and to displace excess caulking laterally in spaced apart relation to said bead.
2. The structure of claim 1 in which said body member has a pair of longitudinally spaced apart bearing surfaces on each side.
3. The structure of claim 2 in which said body has legs on its underside and said legs provide surfaces coplanar with said bearing surfaces.
4. The structure of claim 1 in which the effective bearing plane of said scraper means and the bearing surface of said body are coplanar on each side of said body member.
5. The structure of claim 1 in which the terminal edge is straight.
6. The structure of claim 1 in which the terminal edge is concave.
7. The structure of claim 1 in which the terminal edge is convex.
8. The structure of claim 1 in which the terminal edge incorporates a shallow step ateach end.
9. The structure of claim 1 in which the scraper means comprise tapered edges relieved on their backsides.
10. The structure of claim 1 in which said finger has a tongue portion which is resilient.