US2386662A - Concrete planing machine - Google Patents

Description

Oct. 9, 1945. G. F. cRocK CONCRETE PLANING MACHINE 2 Sheets-Sheet l Filed March 16, 1942 glwucm Tow Patented Oct. 9, 1945 CONCRETE PLANING MACHINE Gregory F. Crock, Atlanta, Ga., assignor to General Floor Company, New York, N. Y., a

corporation of Delaware Application March 16, 1942, Serial No. 434,941

6 Claims.

My present invention relates to machines or implements for smoothing the surfaces of slabs of freshly deposited concrete and embodies a number of features of great utility in the art to which the invention pertains.

A number of different types of implements for grading freshly deposited bodies of concrete, initially smoothing the surfaces thereof, further smoothing and densifying such surfaces, and finally finishing the same by hand or machine driven trowels, have been designed, suggested and actually placed in operation. Customarily, the body of freshly deposited concrete is first screeded or levelled off and subjected to an initial smoothing operation and, in my companion application, Serial No. 445,919, filed June 5, 1942, an effective concrete grading and smoothing implement is disclosed. After a machine or implement of this type has been used, and before final trowelling, it is now common practice to employ a rotary float device, especially in the laying of concrete slabs within buildings, such as floor slabs, where it is not practical to employ concrete surfacing machines of the type which may be and are often used in the laying of concrete highways. The present invention relates particularly to machines or implements designed and intended to be used upon the surface of a slab which has already been subjected to a levelling and preliminary surfacing treatment, the

purpose being to further smooth and densify the surface and place it in condition for final trowelling, the machine being a substitute for a rotary float but having capacity to perform substantially the same functions in a superior manner and at much less cost.

While in the details of its construction the machine may vary considerably without departure from the scope of the invention it may conveniently comprise two elongated concrete surfac smoothing members the work-engaging undersurfaces of which are of novel conformation, together with means for effecting relative longitudinal reciprocatory movement of such members, the arrangement being such that the,

smoothing members may be 'manipulated and transported as a unit. The mechanism is preferably so designed likewise that, when it is in operation, both smoothing members will be longitudinally moved, neither remaining stationary.

The work-engaging undersurface of each member is so designed that, when the implement is drawn manually forward over the surface of a body of concrete by a force applied normally to the direction of its length, the concrete surface is subjected to what might be designated a trowelling action, particles of the upper surface being successively subjected to the action of two relatively inclined smoothing surfaces which are moved in a desired direction while reciprocating transversely to such direction of movement, this by reason of the novel conformation of the Workengaging undersurfaces of the smoothing members. Each such work-engaging undersurface is convex, comprising two angularly disposed plane surfaces which meet in a line which is slightly inclined to the longitudinal or major axis of the member. As such member is reciprocated in the irection of its length or major axis, and is moved bodily in a direction normal to its length, each surface particle of the concrete over which the smoothing surface passes is contacted first by One inclined portion of the members undersurface and thereafter by the second inclined surface, both surfaces being preferably equally inclined to the horizontal.

It is found that an implement so constructed will not only accomplish its intended functions in a superior manner and produce a high-grade result, but will effect a substantial reduction in the cost of surfacing as compared with the results obtained when machines of other types are employed to accomplish generally similar results. By reason of its light weight, the novel conformation of the work-engaging surfaces of its smoothing members and the manner in which these surfaces are simultaneously reciprocated, the machine may be readily drawn forwardly across a concrete surface and the amount of effort required of its operator, per square yard of concrete surface, is remarkably low. It is readily manipulated past columns and other obstructions and hence may be used in the interiors of buildings, despite its very considerable length. Time is saved because of the rapidity with which a large area of concrete may be smoothed in a given time.

By way of example one embodiment of the invention will be disclosed, this embodiment being illustrated in the accompanying drawings in which:

Figurelis a top plan view of the implement or machine;

Figure 2 is a front elevation of the same; Figure 3 is a section on line 3-3 of Figure 1; Figure 4 is a section on line 44 of Figure 1; Figure 5 is a section on line 5-5 of Figure 3;

and

Figure 6 is a section on line 6-6 of Figure 1. The major elements of the mechanism comprise the two smoothing members which are substantially identical in construction and are indicated in the drawings by the numerals l and II, respectively. The smoothing member ID may be designated the forward member and the mem-- ber may be designated the rear member inasmuch as the member H] is closer than member II, to an operator who is grasping handle bar l2, thelmplement being drawn by the operator so grasping bar l2 in the direction indicated by the arrow A, Figure 1, to accomplish its intended functions. It will be observed from Figure 4 that the side members l2a, of the handle extend downwardly and rearwardly from the cross bar l2 to the forward member Hi, the lower ends of the side members l2a being rigidly secured to member ID at spaced points, as indicated in Figures 1 and 4. The smoothing members may be formed in various ways and the specific man ner in which they are constructed is of relative unimportance except insofar as the work-engaging undersurface of each is concerned. These undersurfaces are formed as elongated rectangul'ar metallic plates l3 and M, respectively. The undersurface of each' plate'is divided into two triangularly shaped relatively inclined portions indicated at |3a, l3b, and Ma and Mb, respectively, these portions being similarly inclined to the horizontal and each meeting along a straight line which extends from one corner of the plate to the diagonally opposite corner, this diagonal line for the plate |3 being indicated by the numeral |3c in Figure 1 and the corresponding line for the smoothing member being indicated at Me, the lines of intersection I30 and He being parallel to each other.

Superposed' upon each plate is a truss-like frame comprising longitudinally extending angle bars, suitable vertical members, and such truss or bracing members which may .be deemed to be essential to render the smoothing member as an entirety relatively inflexible and to give the same the necessary strength. The two members are secured together by means which enables them to be manipulated by an operator as a unit, but which permits relative longitudinal reciprocation thereof. Any suitable connecting means capable of accomplishing the desired results may be employed for this purpose, that illustrated in the drawings including pairs of spaced grooved rollers I6 carried" by the forward member NJ and located in trackways or rollways of the smoothing member As shown in Figure 5 the rollers l6 of each pair of grooved rollers are mounted upon the oposite ends of an axle member I! which is in turn rigidly supported in the position in which it is shown by a, frame which includes the parallel rods |8 each of which is secured at two points to the forward member ID. Adjacent flanges of parallel angle members 29 and 2|, forming portion of, or mounted on, the frame of smoothing member H, enter the grooves of the series of rollers l6 and comprise confining trackways for these rollers, permitting movement of the rollers longitudinally of member II, but preventing lateral dislodgment or displacement of the rollers from the positions in which they are shown. By the connections thus described the two members are at all times connected to each other for simultaneous bodily movement in the direction of the arrow A, but are quite free to move longitudinally relatively to each other.

Any suitable means for efiecting relative longitudinal movement of the two smoothing members may be employed and in the drawings a gasoline engine 20 is illustrated, this engine being mounted upon a bed plate 2| and having a power output shaft 22 upon which a grooved pulley 23 is fixed. Pulley 23 is operatively connected to a disk 24, the periphery of which is also grooved, by means of a V-belt 25. The disk 24 is fixed on a shaft 26 rotatably supported in bearing 21 mounted upon smoothing member l0. Likewise fixed upon shaft 26 is a second grooved disk 28, disk 28 being operatively connected to a disk 29, disposed in the same plane,

' by means of a second V-belt 3!]. Disk 29 is fixed uponv the end of a shaft 3| parallel to shaft 26 and rotatably supported in bearings 32 mounted upon the smoothing member II]. An eccentric pin projecting forwardly from disk 29 is indicated at 35 and this pin is connected to a second pin 36 projecting rearwardly from a bracket 31 mounted upon the frame of smoothing member H, by means of a link 38. By the driving connection described the power of motor 20 may be delivered to link 38 and, as the disk 29 is revolved, the link i caused to deliver a thrusting force on smoothing member tending to move this member in one direction, and to thereafter exert a pull on such member in the opposite direction. The reactions of these forces are, of course, transmitted through shaft 3| to the member l0 and, by reason of the fact that members l9 and II have very nearly the same mass and have the same extent of engagement with the underlying concrete, both members will reciprocate when the motor 29 is in operation, one member moving in one direction while the second member is moving in. the opposite direction. By varying the weights of members 0 and or'modifying the areas of their undersurfaces, or by varying both weights and undersurfaces, the extent of reciprocation of one member with respect to the other may be modified. Motion of relative reciprocation may be interrupted without stopping the motor 20 by sliding the motor longitudinally along member H) and to permit this the base plate 2| upon which the motor is supported is slidable and means is provided for adjusting it longitudinally of member II] to tighten or loosen V-belt 25 as may be desired.

The means for sliding the motor and establishing or breaking the driving connection to disk 24 may conveniently include the operating handle 49 fixed on the end of shaft 4| rotatably mounted in bearings 42 secured to member ID. Fixed on shaft 4| intermediate bearings 42 are arms 43 and the free end of each arm 43 is connected to a bracket 44 mounted upon bed plate 2| by means of a link 45. It will be obvious that, by movement of operating handle 40 from its full line position to its dotted line position (Figure 6) the bed plate and motor will be moved in a direction to cause the pulley 23 to approach the disk 24, which results in loosening of the belt 25. The driving connection through belt 25 is rendered operative by placing lever 40 in the positionin which it is shown in full lines in Figure 6.

One or more operators may grasp the cross bar |2 of the handle and may draw the machine in the direction of the arrow A over a previously levelled concrete surface at a speed which will be readily established by observing the results obtained. Very little force is needed to effect the advance of the machine in this manner, ven though the smoothing members be relatively long and the area of contact of the unclersurface of these members with the concrete relatively large. The implement is of great utility, producing an improved smoothing effect, preparatory to final trowelling, at a less cost than that involved in the operation of enerally similar implements of types heretofore suggested or used. It may be most conveniently manipulated indoors but, of course, may be employed if desired in the laying of roadways or concrete slabs generally.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Means for smoothing the surface of a freshly formed concrete floor slab or the like comprising an elongated member adapted to be longitudinally reciprocated while it is advanced over the slab surface in a direction normal to its length, the work-engaging undersurface thereof having two relatively inclined generally flat areas which intersect along a line extending longitudinally of the said member and slightly inclined to the longitudinal axis thereof and neither of which areas is horizontally disposed when said member is positioned to smooth the horizontal surface of a slab.

2. A concrete smoothing member having an elongated work-engaging undersurface, said undersurface comprising two relatively inclined portions which intersect along a substantially straight line slightly inclined to the major axis of said member both portions of said undersurface being slightly inclined to the horizontal when said member is positioned to smooth the horizontal surface of a slab.

3. The concrete smoothing member described in claim 2 in which said undersurface is rectangular and the two portions thereof triangular, the line of intersection extending from one corner of said surface to the diagonally opposed corner.

4. Concrete surfacing mechanism comprising in combination, parallel elongated Work-engaging members the undersurface of each of which is, in section, formed as a down-pointed V, having a ridge extending diagonally to the length thereof and said ridges being parallel, and means for longitudinally reciprocating said members.

5. The combination set forth in claim 4 in which the undersurfaces of each member, on both sides of the diagonal ridge thereof, are relatively inclined and make equal angles with the horizontal.

6. The combination set forth in claim 4 in which the means for longitudinally reciprocating the said members is supported directly upon said members and is designed and constructed to effect simultaneous reciprocation of said members.

GREGORY F. CROCK.

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