US1995450A - Adjustable screed - Google Patents

Description

March 26, 1935. A. w. FRENCH ADJUSTABLE SCREED Filed Aug. 19, 1933 2 Sheets-Sheet l I 1 l LIM H I I I H I h Hm March 26, 1935. A. w. FRENCH ADJUSTABLE SCREED 2 Sheets-Sheet 2 Filed Aug. 19, 1933 R NI M 1 w R N A? 11 E I x v 0 0 0 0 @N m w Patented as, 1935 UNITED STATES ADJUSTABLE SGREED Alfred w. French. Chicago. 111.. llllml' to Blow- Knox Company, Blawnox, Pa, a corporation of I New Jersey ammo August 19. 1933, Serial No. mm

scum. (0!. 94-45) his invention relates to a screed which may be employed for-imparting the desired contour to-material being shaped, more particularly to materials being poured for building a concrete 0n concrete roads as generally built in the past, the roads are crowned from one inch to two inches in the center, depending upon the width of the road. Such a contour insures good drainage from thzfenter to both sides when the road is otherwise lev Until recently, roads were also crowned on the curves; but the engineering practice in this regard is now being modified so that curves are frequently banked from the inner side of the road to the extreme outer edge. For this and other reasons, the crown at the center of the road may be completely eliminated, so that in the middle of a curve, the road surface conforms to a straight line from edge to edge.

At the present time, engineers prefer to retain the crown on the roads where the latter are straight, and to eliminate the crown on curves where the curve is banked. To give a workmanlike finish to the road, it is desirable to.have a gradual transition from the crown section to the straight section. The necessity of accomplish-'- ing this transition has slowed up the work of shaping the concrete at the curved portions of the road. Various expedients have been adopted for supplementing the screed used where the road is crowned.

T he purpose of the present invention is to do away with such delay at the curve of a road and to make it possible to use the screed for the entire road, changing with facility the crown of the screed in passing from the straight road to the curved portion. In fact, in accordance with my invention, the screed is adjustable so that the contour or crown may be changed by the operator of the finishing machine while the latter is in motion performing its ordinary function. In the drawings in which an illustrative embodiment of my invention is shown,

Fig. 1 is a plan view, a portion of the screed at the right end being broken away;

2 is a similar view in side elevation;

Fig. 3 is a detail view with parts in section illustrating the manner in which the contour is adjusted;

Fig. 4 is a section on the line IV-IV of Fig. 2;

Figs. 5\ and 6 are detail views of face plates for striking oif surplus material;

Fig. 7 is a detail view of an indicator from which the operator may read the crown or con-- tour directly;

-- Fig.8 is a detail view similar to Fig.3 showing the yoke and turn buckle forming part of the operating mechanism; 1

Fig. 9 is a sectional view on linelX-IX of Fla. 8: and- Fig. 101s a perspective view of a stiffening angle.

The screed is to extend from one side of the road to the other, and accordingly has what may 1 be considered a back-bone ormain frame built up as indicated in Fig. 4 of two channels 12, 12 spaced apart with their stiff sections or webs vertically disposed. Suitable ties 13 exten across to brace the two channels 12.

In order to provide a shaping or smoothing member which may be used to impart a contour or crown of desired shape to the road, this smoothing member is made deformable; and in the embodiment illustrated is a channel 15 secured beneath The horizontal legs 19, 19 and 19" of the bell 30 I cranks 18 are not all of equal length and are connected to the strip or channel 15 by uprights 20. The connection between each upright 20 and the corresponding bell crank is shown as a pin and vslot connection 21 to provide the necessary lost 35 motion. These bell cranks function as adjusting elements for determining the contour of the elongated smoothing member 15. As these bell cranks constitute connections between the main frame and the smoothing member 15, by rocking 40 the bell cranks about their pivots 1'7 the various portions of the strip or elongated smoothing member 15 will be displaced relative to the main frame. As the horizontal legs 19, 19' and '19-" of the bell cranks are not all of equal length, the 45 different portions of the channel or strip 15 are displaced to difierent extents. Adjacent the ends of the strip 15 are pivots 17' on which are directly pivoted uprights 20', thus pivotally connecting, 50 the ends of the strip 15 to the rigid frame.

I have provided mechanism for rocking all of the bell cranks simultaneously. Rods 22 extend in opposite directions from a central yoke 23, and the upstanding legs of the bell cranks are piv- 2 otally connected to the rods 22. A turn buckle 25 is inserted in one ofthe rods 22 so that-by.

tightening or loosening the turn buckle 25, the

bell cranks may be simultaneously rocked on and the remainder at the left end.

It is desirable to have an indicator which will in-' form the operator at all times as to the contour of,

- the road. This is of particular convenience as the finishing machine is approaching a turn in the road, and where the crown is gradually eliminated to merge with the level surface of a banked turn. I have provided such an indicator mounting the calibrated element 29 thereof on the channel 15 and the pointer element 30 thereof on the main frame of the screed. Either one of these elements may be mounted on the main frame with the other eleinent mounted on the channel 15; but I prefer the arrangement illustrated.

In finishing the road, the screed may be moved longitudinally of the road by hand, but preferably the screed is operated by the usual finish- -ing machine. At the center of the screed I have provided a mounting 32 for a universal coupling 33. The mounting 32 is constructed by securing a plate 35 to the channels 12, fixing a'casting' 36 to the plate 35'and stiffening the structure by a stiffening angle 3'7. The universal coupling 33 is mounted on the casting 36, and functions to impart oscillatory motion from a pitman (not shown) to the screed. The crank arm which actuates the pitman may not be precisely alined with the screed and, therefore, a universal coupling at this point is desirable. The method of connecting the screed provided by my invention to the finishing machine forms no part of my invention and hence further detailed description of the universal coupling 33 is deemed unnecessary.

This structure at the center of the screed makes it impossible to extend the rods 22 continuously across the top of the screed. The yoke 23 is provided so as to pass around this central structure.

As the screed is advanced and oscillated, it may be guided by operators, handles 39 being provided at the ends of the screed. It will be understood that the structure at the right end of the screed is the same as the structure at the left end, the showing of the structure at the right end being omitted so that the drawings may be 42 and are not drawn up sufllciently tight to interfere with the adjustment of thecurvature of the strip or channel 15.

Certain of the advantages of my invention arise from the provision of a deformable strip or smoothing member whose contour may be determined by connection's spaced along its length. Further advantages arrive from the ability to adjust the curvature of this smoothing'member by the operation of a single member. which is conveniently located where the operator may effect such adjustment without moving from his seat on the finishing machine.

While I have illustrated and described one preferred embodiment which my invention may assume, it will be understood that my invention is not limited to the details of such embodiment, and that more particularly m invention is not limited to the structure provided for attachment of the pitman actuated by the finishing machine which is present on finishing machines where my invention is not used, and is described herein only tomakeclear the reasonfortheyoke 23; butmy invention may be otherwise embodied and practicled within the scope of the following claims.

claim:

1. In a screed, the combination with a rigid frame of a deformable elongated smoothing member adapted to engage the material and means for bending said smoothing member to impart a desired curved contour to said member, said means comprising a plurality of bell crank connections at spaced points along the length of said smoothing member, and a single operating member for simultaneously adjusting said connections.

2. In a screed, in combination, a rigid frame, a flexible elongated smoothing member, and means for bending said smoothing member to a desired curvature comprising a plurality of pivotally mounted bell cranks spaced longitudinally of said smoothing member andsupporting said member from said frame, and means for rotating said bell cranks on their pivots.

3. In a screed, in combination, a rigid frame, a flexible elongated smoothing member, and means for supporting said member from said frame comprising a plurality of bell cranks spaced longitudinally of said smoothing member, .not all of the legs of said bell cranks connected to said smoothing member being of equal lengths whereby displacement of different portions of the smoothing member may be' effected to different extents.

4. In a screed, in combination, a rigid frame, a deformable elongated smoothing member, and means for springing said member to a desired curvature comprising a plurality of bell cranks pivotally connected to the frame and the smoothing member and means including a turn buckle for simultaneously rocking said bell cranks.

5. In a screed, in combination, a rigid frame, a deformable elongated smoothing member adapted to engage the material, means for supporting said smoothing member from said frame and flexing said member to a desired curvature comprising a plurality of hell crank connections between said frame and smoothing member at spaced points along the member, said connections being operable to displace the adjacent portions of said member not all to the same extent, and means for simultaneously operating said connections.

6. In a screed, in combination, a rigid frame, a flexible elongated smoothing member pivotally connected adjacent its ends to said frame, means for bending said smoothing member to a desired curvature comprising a plurality of bell crank connections at spaced points along said member, and means for simultaneously operating said connections to displace the corresponding portions of said member.

7. In a screed, in combination, a rigid frame, a

deformable elongated smoothing member, meansfor springing said member to a desired curvature comprising a plurality of hell cranks, not all of and for flexing said member to a desired curvathe legs of said bell cranks connected to said ture comprising connections between said frame smoothing member being of equal length, and and smoothing member at spaced points along means including a turn buckle for simultaneousthe member, at least one of said connections be- 5 1y rocking said bell cranks. ing of such character as to flex the member to 5 8. In a screed, the combination of a rigid frame, a different extent than the adjacent connections,

a deformable elongated smoothing member and a single operating member for operating said adapted to engage the material, means for supconnections.

porting said smoothing member from said frame ALFRED W. FRENCH.

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