US2804767A - Gun type trowel - Google Patents

Description

Sept 3, 1957 H. P. scHoEN 2,804,767

GUN TYPE TROWEL Filed June 2l, 1955 2 Sheets-Sheet l Sept 3, 1957 A H. P. scHoEN 2,804,767

'GUN TYPE: TROWEL l Filed June 21, 1955 2 Sheets-Sheet 2 :Ezr

@Harz/9 P Schoen.

nited States Patent GUN TYPE TROWEL Harvey P. Schoen, Elgin, Ill.

Application June 21, 1955, Serial No. 517,028

2 Claims. (Cl. 72-138) This invention relates to gun type trowels for spreading finishing material such as plaster, mortar, cement and the like on wall surfaces, particularly for finishing the joints of dry wall constructions either flat or cornered.

Heretofore, various difficulties were encountered in work of this kind, mainly when working with trowels attached to the outlet nozzles of plastering machines and the like. The new gun type trowel allows rapid, yet accurate, smooth and long continued finishing of such areas.

The improvement has been achieved by a novel duct structure between the gun and the blade ofthe trowel, distributing the finishing material in suitably predetermined manner before it reaches the blade. A joint can thus be filled and covered with less manual squeezing of the material by the trowel blade, and correspondingly with greater easel and the same, greater accuracy than before.. V Y y The details will be understood more readilyuponv a perusual of theN description of preferred embodiments, which follows.

In the drawing:

Figure 1 is a perspective view of a caulking gun equipped with a trowel according to this invention, particularly for work on at dry wall surfaces.

Figure 2 is a side View of the trowel.

Figure 3 is a section taken along lines 3-3 in Figure 2.

Figure 4 is an enlarged section taken along lines 4 4 in Figure 2.

Figure 5 is a side view of a trowel according to this invention, for work on vertical outside corners.

Figure 6 is a front view of the trowel of Figure 5.

Figure 7 is a top view of the trowel of Figures 5 and 6, taken along lin'es 7-7 in Figure 5; and

Figure 8 is a top View of a trowel according to this invention, for work on vertical inside corners.

Referring first to Figures 1 to 4:

Thecaulking gun 10 has a conventional feeder, valve or other mechanism .11 for the regulated discharge of the finishing material into the trowel. The new trowel has anintake fitting 12 which is shown as havinginternal threads 13 whereby it can be connected with the discharge end of the gun. Anadaptor 14 in form of a short and suitably trimmed pipe nipple connects theintake member 12 with the interior of thehollow portion 15 of the trowel proper. This hollow portion extends along the front or working side of aresilient trowel blade 16. It discharges adjacent theworking edge 17 of said blade, through a series ofdischarge nozzles 18, a Short distance below said edge; said series of nozzles extending symmetrically over a middle portion of the width of theblade 16 and being shorter than the same.

Thedischarge openings 18 are advantageously formed by means of awall member 19 which is generally flat and approximately parallel with theblade 16. Thiswall 19 is equally resilient as theblade 16, about any axis normal to theedge 17, but is corrugated in directions approximately parallel with theside edges 20, 21 of the to employ such a design in the present case.

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blade. High points of such corrugations are secured to the front surface of the blade, for instance by spot welding or soldering, thereby defining thedischarging openings 18 between thewalls 19 and 16. The finishing material is guided from thehollow inlet section 15 to thedischarge openings 18 byside walls 22 interconnecting theparallel walls 16, 19 and secured thereto as by soldering or welding.

It is usual in the construction of trowel blades to employ a forwardly aring design such as that of a triangle or blunted triangle or trapezium, and it is preferred Accordingly theside walls 22 are also given a forwardly flaring direction. However, it is preferred to backwardly extend theirlower portions 23, connecting them with the material-receivingchamber 15, and to make the side andbottom walls 24, 25 of the material-receiving section substantially coincident with the corresponding edges of the trowel. Thus the material-receiving section itself has substantially pentagonal shape as best shown in Figure l, whereby the fiow of the finishing material from thegun 10 is directed into the desired direction parallel with theblade 16 with a minimum of fluid friction and a maximum of uniformity of distribution. The distribution of the flow of the finishing material, over thedifferent orifces 18, is substantially achieved in the narrowed section orthroat 26 of the chamber and duct, between thewalls 22 and 23, and not as heretofore at the outlet end of the duct itself. At the same time the aforementioned resiliency of the duct and trowel walls,

' about any axis normal to thetrowel edge 17, safeguards desirable smoothness of operation, wherein the entire trowel structure and the finishing material guided thereby will follow the surface contoury of the dry wall'being finished, rather than` any arbitrary contour of theltrowel itself. Heretofore the discharge nozzles of gun type trowels interfered with such smooth operation.

In operation, the finishing material is supplied from thegun 10 to the trowel, for instance by the pressure of a preload spring in the gun, not shown, under control of the mechanism 11. The material arrives in thepentagonal chamber 15 and ows therefrom along the front of theblade 16 to theopenings 18; each opening receiving a predetermined, for instance equal part of the total material flow due to the effect of the throat orrestriction 26, and in spite of slight distances between thedifferent openings 18 from the throat and unavoidable slight distances in orifice areas due to the attachment of the corrugations to the blade.

The gun and trowel may be held at the approximate angle shown in Figures 2 and 4, at the start of operation. When an initial supply of finishing material has been discharged, theangle 27 between thewall 28 and theblade 16 is usually made more acute, incident to which there is also applied some exure of theresilient blade 16, about a horizontal axis. Such flexure is limited to the portion of theblade 16 between the -openings 18 and theedge 17, thereby avoiding interference with the uniformity of material flow upon any change of such flexure and angular direction of the blade. ln earlier gun trowels the plaster had to be Very careful in this respect whereas the operation is greatly simplified by the combined distributing and structural effects of the present flat andcorrugated members 16, 19.

Thus the finishing of a joint in a dry wall, or any similar operation, can be performed rapidly, easily and yet very accurately and smoothly and without irregular material accumulations at any point. The operation can be performed in the same manner in spite of slight convexity and/or concavity in a dry wall panel, caused by the nailing thereof of the wall studs, by warpage of the wall under construction 0r similar disturbances, which Patent-eed sept.V 3', 1957l j were a distinct problem in the use of the finishingequipment heretofore known. The new gun trowel is practically independent of such disturbances and problems.

Referring now to Figures 4 to 7:

The invention isV here applied to the finishing ofra corner in ay dry wallan operation wherein the problem of uniform material distribution has been particularly disturbing with the use of equipment as previously known.

The corner trowel as shown has a supply nipple 52 leading toreceiver chamber 55. In the present case the receiving chamber is shown as being bent in a vertical plane, an expedient which can be used also in the flat trowel of Figures l to 4, in order to facilitate iinishing of bottom porti-ons of a vertical joint. Thetrowel blade 66 in the present case is bent into a roof or prism shape, with the front sides of the blade including a horizontal angle 67which usually should be 9() degrees; accordingly, when and as the trowel is constructed for a slightly inclined position as best shown inFigure1 5, the included angle and the plane of Figure 7 will usually be slightly more than 90 degrees, thereby maintaining the correct angle and actual use.

A series ofdischarge openings 68 is again formed, symmetrically with the top edge of theblade 66 and extending over a part of the length of that edge. Again a corrugated wall is used for this purpose which in this case is shown as havingsections 69, 70 lying at thesame angle 67 as described. The connection between4 thereceiving chamber 55 and the apertures 63 is provided bywall members 71, 72, 73, extending approximately parallel with the contour of the blade which has been described.

Again a restriction in the ioW of the iinishing material, prior to its arrival at thedischarge openings 68, is applied. In the present case it is occasioned mainly by the bending of the receiving chamber SS about asharp bend 74,V an expedient which as mentioned can be used also in other types of trowels in accordance herewith.

Referring nally to Figure 8 it will be noted that a 4 trowel in accordance herewith can be constructed to t into an inside corner in approximately the same manner in which they trowel of Figure 7 fits around an outside corner. Asupply nipple 82 feeds the material into a sharply bentreceiving chamber 85 following the proper contour of thecorner trowel 86 and discharging uniformly through a series of openings S8 which extends along and slightly below the top edge of the trowel. In similar manners other special trowels can be constructed in accordance with the present invention. In special cases it is of course possible also to modify the discharge of material fromdifferent openings 18, 68 or 88 in order to suit special materials and/ or joint constructions. Many other modifications are possible, all within the scope of my claims which follow'.

I claim:

l. A gun type trowel comprising a resilient trowel blade having an edge, a resilient wall symmetrically secured to and spaced from the trowel blade having an edge spaced a short distance below the trowel edge and adapted to form a receiving chamber and a duct with the blade, said wall having the area thereof adjacent to saidA edge corrugated to define with the blade a plurality of laterally spaced discharge nozzles of substantially uniform size, said duct being adapted to distribute heavy consistency fluid material therethrough uniformly before such flow arrives in the area of the corrugations adjacent the trowel edge, and means to feed such material through the duct and out of said nozzles.

2. A trowel as described in claim 1 wherein the blade is bent so that it substantially follows the contour of a corner.

References Cited in the ile of this patent UNITED STATES vPATENTS l Selley May 17, 1904

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