US2896441A

US2896441A - Adjustable joint trowel

Info

Publication number: US2896441A
Application number: US580889A
Authority: US
Inventors: Jo W Tucker
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-04-26
Filing date: 1956-04-26
Publication date: 1959-07-28
Anticipated expiration: 1976-07-28

Description

J. W. TUCKER ADJUSTABLE JOINT TROWEL July 28, 1959 2 Sheets-Sheet 1 Filed April 26, 1956 &

INVENTOR Jo W Tucker ATTORNEYS July 28, 1959 J. w. TUCKER ADJUSTABLE JOINT TROWE'L 2 Sheets-Sheet 2 7 Filed April 26, 1956 1N\;ENTOR J0 W Tucker ATTORNEYS United States Patent 2,896,441 ADJUSTABIJE JOINT TROWEL In W. Tucker, El Paso, Tex.

Application April 26, 1956, Serial No. 580,889

3 Claims. (Cl. 72-136) This invention relates to new and useful improvements in joint trowels.

The invention is particularly concerned with trow'els for the bedding of tape in the joints of gypsum wall board, as used in building construction, and for the filling of such joints to present a smooth and apparently continuous finished surface. At the present time, numerous types of trowels are used for this purpose, but they are either diflicult to use properly, or fail to finish the joint in such a manner that the joint becomes substantially invisible after decorative coatings, such as paint, are applied to the wall surface. These trowels may have varying degrees of flexibility, and may have a degree of lateral flexibility so as to provide for feather edges on the lateral portions of the bedding or filling cement. In most instances, however, the feather edging which is achieved is not smooth and continuous in curvature or cross-section since the trowels tend to flex at a given point or within a relatively small zone so that the resultant joint presents a plurality of relatively flat surfaces connected by arcuate surfaces.

In finishing a joint of this type, it is desirable that the layer of cement be thickest in the area immediately overlying the joint between the adjacent wall boards, and taper smoothly, with some slight convexity, outward to lateral feather edges spaced on either side of the joint. To achieve this result, and to cope with the various types of joints and jointing of materials which are encountered, it is desirable that the trowel flex fairly uniformly in a lateral direction in use, and that the degree of flexing, or the radius of curvature of the trowel blade edge in use, be subject to variation or adjustment as found necessary or desirable.

It is, therefore, one object of this invention to provide an improved joint trowel having a flexible blade adapted to yield or bend to provide a working edge of the de sired curvature for producing feather-edged filling overlying the joints of Wall boards or wall panels.

It is a further object of the invention to provide an improved trowel, of the character described, in which provision is made for regulating or adjusting the degree of flexing or curvature of the woking edge of the trowel blade, and in which the trowel blade is readily replaceable when dam-aged or worn, or replaceable by a blade of greater or lesser flexibility.

Another object of the invention is to provide an improved joint trowel having a working blade adapted to undergo flexing whenapplied to the work surface, but to flex to a greater extent at a central portion and to progressively lesser extents toward its end portions to provide a working edge of smooth and uniform curvature, and in which the degree of flexing at the end portions of the working blade may be adjusted or regulated in order to vary the curvature of said working edge, and thus vary the contour of the joint produced through use of the trowel.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein:

Fig. 1 is a top plan view of a joint trowel constructed in accordance with this invention,

Fig. 2 is a front elevational view of the trowel,

Fig. 3 is an end elevational view of the trowel,

Fig.4 is a transverse, vertical, cross-sectional view, taken on the line 4-4 of Fig. 2,

Fig. 5 is a. view in perspective of the trowel illustrating the application of cement to a wall joint and the curvature of the working edge of the blade when adjusted to minimum curvature, and

Fig. 6 is a view, similar to Fig. 5, showing the trowel adjusted for maximum curvature of the working edge of the blade.

In the drawings, the. numeral 10 designates an elongate, transverse frame member of inverted U-shaped cross-section and having a depending. rearward leg or flange 11 joined to a front leg or flange 12 by a transverse upper web 13 (Fig. 4). A suitable handle 14, formed of wood or any other suitable material, is notched to receive the upper edge of the frame member 10 and is joined thereto by a screw 15, shown in broken lines (Fig. 3). For ease of use, the handle 14 desirably extends rearwardly and slightly upwardly from the frame 10, but may be positioned in any desirable or suitable relationship with respect to said frame.

An elongate, rectangular, trowelling bladej16, formed of spring steel or some other suitable flexible or springlike material, is coextensive with the frame 10 and carries at its rearward edge an upstanding flange 17 joined to the blade through a smoothly curving transverse section 18, and desirably being formed integrally or of one piece with said blade. The upper edge of the flange 17 is received within the groove of the channel-like frame member 10 and abuts the rearward flange 11 thereof (Fig. 4). An angular bracket 19 is provided near each end of the frame 10 and has a vertical leg 20 extending upwardly into the channel member .10 and overlying the flange 17, and a forwardly-extending leg 21 overlying and spaced above the blade 16. Bolts 22 extend through the flanges 11 and 17 and the vertical legs 20 of the brackets 19, and receive nuts 23 within the channel-like frame member 10 for securing both the blade 16 and said brackets thereto.

The forwardly-extending horizontal legs 21 of the brackets 19 extend any suitable or desirable distance forwardly over the upper surface of the blade 16, it having been found preferable that the legs 21 extend from onethird to one-half of the dimension of said blade taken perpendicularly to the frame 10.

As shown in Figs. 1 and 4, each of the brackets 19 is provided in its forwardly extending leg 21 with an elongate slot 24 having its longitudinal axis disposed perpendicularly to the frame member 10 and extending forwardly over the upper surface of the blade 16. Suitable screws 25 extend downwardly through the slots 24 and by means of nuts 26 clamp to the underside of the forwardly-extending legs 21 angular stop or pressure elements 27 having rearwardly-extending legs 28 underlying and clamped to the underside of said legs 21, and short, downwardly-extending feet or lugs 29 which engage the upper surface of the blade 16. The feet 29 provide points of support against upward flexure of the blade 16, these points being positioned near the ends of said blade and being adjustable toward and away from the forward or working edge 30 of said blade to vary the degree of flexibility of those portions of the blade immediately for-.- ward of said feet.

. a l 3 It is pointed out that movement of the screws 25 toward the rear of the slots 24 will move the feet 29 away from the working edge 30 of the blade 16 and cause the end portions of said blade forward of said-feet to be more flexible because there is a'greater expanse thereof unsupported by the frame 10 or said feet. Similarly, movement of the screws 25 toward the front ends of the slots will move the feet 29 toward the working edge'of the blade, thus reducing the width of the unsupported end portions of the blade and decreasing the flexibility thereof. a

The central portionof the blade 16 is supported only by the frame 10 and retains substantially the same degree of flexibility at all times, and hence, as illustrated in Figs. and 6, adjustment of the feet 29 toward and away from the forward or working edge 30 of-the blade 16 will result inthe blade flexing in use to provide a greater or lesser degree of transverse curvature and provide a joint of greater or lesser thickness at its central portion.

- At the same time, the desired, uniform flexibility or curvature of the blade is retained to the extent that the blade will flex smoothly and to progressively lesser degrees from its central portion to its end portions, and accordingly, a smoothly curved joint with feather edges will be obtained. Such a joint is highly desirable in that it is substantially-invisible when covered by decorative coatings.

There is no flexing of the blade at localized spots, resulting in a joint that remains visible after covering or painting, but instead, a smoothly and uniformly curved surface for the joint cement is achieved. At the same time, the radius of curvature or degree of curvature of the joint surface may be regulated or varied at will by suitable adjustment of the elements 27.

Of course, by tilting the trowel with respect to the work surface, the effective surface curvature of the layer of joint cement may be varied without adjustment of the elements 27. Most workmen, however, have an adopted style of use of such trowels, and the provision for adjusting the transverse curvature of the blade 16 is most advantageous in coping with the different joint materials and the different types of joints encountered in building construction. Further, the adjustability of the blade permits the workman to adapt the blade to his particular style of operation whereby better work may be accomplished with less lost motion and waste of time.

Of course, the blade 16 is readily detached from the frame by removal of the bolts 22, and may be replaced by a new blade, or by a blade of greater or lesser flexibility or of differing dimensions. The structure is extremely simple and economical to manufacture, and yet is durable and is convenient to use. Proper adjustment of the elements 27 will fit the tool to the working habits of the particular workman, or will enable the workman to adapt the tool to various joint forming problems.'

A typical wall board joint is shown in Figs. 5 and 6, and includesa pair of abutting wall board panels 31 having their joint or abutting edges covered by a tape 32 over which the bedding and filling material or cement 33 is placed. It is desirable that the central portion of the layer of filling material, immediately overlying the tape 32, be of relatively greater thickness at the central portion 34 than the lateral portions 35, and that the latter feather edge smoothly into the surface of the 4 v v panels 31. It is also desirable that the curved outer surface of the layer of filling material or cement be smoothly curved and present no planar surfaces or sharply curved surfaces, but flow in a smooth continuous, and substantially uniform, curve from one feather edge to the other. By longitudinal movement of the trowel described herein lengthwise, of the joint, the filling cement is applied thereto in the desired manner, as illustrated in Figs. 5 and 6, and at the same time excess quantities of said cement are prevented from flowing outwardly over the edges or end portions of the blade 16. By rearward or forward adjustment of the elements 27, the transverse curvature of the forward or working edge 30 of the blade 16 may be decreased (Fig. 5) or increased (Fig. 6) and the thickness of the central portion 34 of the joint filling material correspondingly decreased or increased.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the. details of the illustrated construction may be made, within the scope. of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. An adjustable joint trowel including a rectangular flexible blade having a working edge on one of its longitudinal margins, the blade being relatively wide and of greater length than width, a substantially coextensive frame member attached to the opposite longitudinal margin of said blade, a bracket attached to each end portion of the frame member and extending laterally therefrom in overlying spaced relation to said blade,the lateral projection of the brackets being not greater than onehalf the width of said blade, support elements extending transversely of said blade in overlying engagement with its end portions and terminating between its longitudinal margins for preventing upward flexure of the end portions of the working edge while permitting upward flexure of the intermediate portion of said edge, and means for adjustably fastening the support elements to said brackets for transverse movement between the longitudinal margins of said blade to vary the curvature of said working edge when said blade is flexed.

2. An adjustable trowel as set forth in claim 1 wherein the support elements are spaced from the blade and have feet depending from their outer ends for engagement with said blade.

3. An adjustable trowel as set forth in claim 1 including an upstanding coextensive flange on the longitudinal margin of the blade opposite its working edge, the brackets being angular and having upright legs overlying the flange and substantially horizontal legs to which the support elements are adjustably fastened, and common means for connecting the upright legs and flange to the end portions of the frame member.

References Cited in the file of this patent UNITED STATES PATENTS 1,297,541 Campbell Mar. 18, 1919 1,744,097 Baker et a1. Jan. 21, 1930 2,301,498 Ames Nov. 10, 1942 2,519,946 Voelker et a1. Aug. 22, 1950 2,725,740 Borgstrom Dec. 6, 1955 2,800,672 Gilyan July 30, 1957