US2999261A - Bull float - Google Patents

Description

P 1961 s. D. LAPHAM 2,999,261

BULL FLOAT Filed Oct. 10, 1955 INVENTOR. S/DNEV D. LAPHAM ATTORNEYS United States Patent 2,999,261 BULL FLOAT Sidney D. Lapllam, RED. 2, Box 316, Martinez, Calif.

Filed Oct. 10, 1955, Ser. No. 539,310 3 Claims. (Cl. 15-2353) This invention relates to and in general has for its object the provision of a bull float wherein the angle between the bull float handle and the bull float shoe varies automatically in response to the change in the direction of movement of the shoe.

Basically, a bull float consists of a shoe rigidly fixed to a push-pull operating handle, and which is moved back and forth across wet concrete for the purpose of leveling said concrete prior to smoothing or finishing the leveled concrete. In such a leveling operation, the shoes should be maintained level or slightly inclined in the direction of the travel of the shoe so that the concrete can be properly worked. The only .way of controlling the angularity of a fixed-handle bull float is to raise or lower the handle, and. when long handles are required because of the concrete area being processed, this becomes awkward and diflicult.

More specifically, the object of this invention is the provision of a bull float wherein the bull float shoe is attached to its handle through an inverted trapezoidal linkage to constrain the angle between the shoe and the handle automatically to decrease in response to a pull on the handle and to increase in response to a push on the handle when the shoe is in traction with a body of concrete.

A further object of this invention is the provision in a bull float of the character above described of means, operable in response to the rotation of the bull float handle, for varying and limiting the extent to which the angle between the shoe and its handle changes in response to the push and pull on the handle.

Still another object of this invention is the provision in a bull float of the character above described of means for locking the bull float shoe to its handle at any desired angle in response to the rotation of said handle.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where those forms of the invention which have been selected for illustration in the drawings accompanying and forming a part of the present specification, are outlined in full. In said drawings, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claims may be embodied in other forms.

Referring to the drawings,

FIG. 1 is a top plan view of a bull float embodying the objects of my invention.

FIG. 2 is a vertical midsection taken on the section line 2-2 of FIG. 1.

FIG. 3 is a fragmentary transverse vertical section taken on the section line 3-3 of FIG. 2.

The hull float shown in these various figures comprises a rectangular wooden shoe I faced with a sheet of rubber 2 and fastened to a rectangular metal angle frame 3 by bolts 4.

Secured to the frame 3 on either side of its transverse center line are upstanding flanges 5 and 6, and welded to and hedging the side members of the frame 3 is a central strap 7. Welded to the upper face of the strap 7 is an upstanding web 8 formed with a notch or valley 9 defined by downwardly converging, inclined edges or walls 11 and 12.

Journaled in and extending between the flanges 5 and 6 are front and rear offset rods or links 13 and 14 pro- 2,999,261 Patented Sept. 12, 1961' vided with central horizontal and parallel portions 15 and 16. Pivoted on the horizontal link portions 15 and 16, and bridging such portions, are a pair of upstand ing, parallel plates 17 and 18, and interconnecting these plates and forming a rigid structure therewith, are a front pair of upper and lower parallel bars or straps 19 and 21 and a rear pair of parallel bars or straps 22 and 23.

Welded to and between the bars 19 and 21 is a sleeve 24, and welded to and over the front end of the sleeve 24 is a plate 25. Rigidly attached to the plate 25 coaxially with the sleeve 24 is an inwardly extending threaded stud 26 of a diameter substantially smaller than the diameter of the sleeve 24.

Welded to and between the rear bars 22 and 23 isa sleeve 27 coaxial with the sleeve 24 of the same internal diameter.

Extending through the sleeves 27 and 24, with fairly close clearance, is the forward section 28 of a tubular full float operating handle 29, the front end thereof being threaded over the stud 26 and being arranged to have substantial forward and rear travel thereon.

Eccentrically secured to the handle section 28 between the sleeves 24 and 27 by pins 31 and 32 is a cam disc 33 accommodated within the notch or valley 9 of the web 8.

Secured to the free end of the handle section 28 by a coupling sleeve 34 is an outer handle section 35, the two handle sections being of such lengths as to produce together an operating handle of from 18 to 20 feet long.

As a result of this construction, and by particular reference to FIG. 2, it will be seen that the shoe and its operating handle have been interconnected by what may be referred to as an inverted trapezoidal linkage in contrast to a parallelogrammatic linkage. If, as shown in FIG. 2, the cam disc 33 is in its lowermost position, and in substantial contact with the bottom of the V- shaped notch or valley 9, the linkage will be locked against movement, thereby to produce a rigid structure of the shoe and its handle. If, on the other hand, the operating handle is rotated axially through so that the narrowest portion of the cam disc is facing downwardly as shown in dash line in FIG. 3, the handle can be bodily translated forward and backward relative to the shoe. Here it should be noted that the dimensions of the cam disc, its eccentricity, and the height or depth of the notch or valley 9 should be such that in all positions of the cam disc, its rim will always be disposed within the confines of the notch. Furthermore, it should be noted that when in the unlocked position of the earn, the operating handle is moved rearwardly relative to the shoe, both of the links 13 and 14 will rotate clockwise about their pivotal points with the flanges 5 and 6. However, the front link 13 will be rising, whereas the rear link 14 will be descending, and as a result, the angle between the shoe and the handle will decrease until the lower rim of the cam engages the left wall of the notch 9. 0n the forward movement of the handle relative to the shoe the reverse action will take place.

By rotating the cam disc 33 to some position intermediate its high and low positions, the amplitude of movement of the handle relative to the shoe is correspondingly restricted, and consequently, the degree of variation of the angle between the shoe and the handle.

If the cam disc is centered with respect to the notch 9, the amplitude of the angle through which the shoe is permitted to move in a clockwise direction will be equal to its movement in a counterclockwise direction. However, by screwing the handle forward or backward the amplitude of movement of the shoe in one direction relative to the opposite direction can be changed at will.

The frictional resistance or adhesion between the shoe and the concrete being worked is, of course, suflicient to 2,ane,ee1

hold the shoe momentarily stationary upon a change in the direction of movement of the operating handle.

"It will, therefore, be seen that 'I have provided a hu1l float wherein its shoe and handle can be rigidly locked by a mere rotation of the handle of not more than 180?, wherein the angle between the shoe and handlewill automatically vary in response to a change inthe axial direction of movement of the handle relative to the shoe, and wherein amplitude of change of such angle can be controlled in response to the axial rotation of the handle.

For the purpose of the claims appendd hereto, the parallel plates 1.7 and 1-8 and the bars or straps 19 and 21, and 22 and 23 can be consideredas frame or rocker to which the bull float shoeis linked and to which the bull float handle is threadedly engaged.

I claim:

I. A bull float comprising: a shoe and rocker interconnected by a pair of spaced upwardly diverging links; a handle threadedly connected to said rocker transversely of said shoe; an upwardly extending web fixed to said shoe in the vertical plane of said handle, said Web being formed with a V-shaped cam follower track; and a circular cam follower mounted on said handle eccentrically thereof and for rotation within the confines of said notch.

2. A bull float comprising: a shoe; a handle mount disposed over said shoe and rockahly connected thereto by a pair of upwardly diverging links; a handle rotatably mounted in said handle mount transversely of said shoe; a web extending upwardly from said shoe in the vertical plane of said handle, said web being formed with a V- shaped cam track; and a camt'rack follower mounted on said handle for rotation therewith within the confines of said cam track.

3. A bull float comprising: a shoe; a handle mount disposed over said shoe; ahandle rotatably mounted in saidvhandle mount transversely of said shoe for rotation on its own axis; upwardly diverging links interconnecting said shoe and said handle mount for rockable motion; a V-shaped cam track extending upwardly from said shoe in the vertical plane of said handle; and a cam track follower eccentrically mounted on said handle within the (confines of said cam track and arranged when rotated to its lowermost position to snugly seat in the lower end ofsaid cam track.

References Cited in the file of this patent UNITED STATES PATENTS Abram May 21, 1929

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