IE42107B1 - Concrete screeding appliance - Google Patents

Abstract

1492776 Screeding appliance P A MURPHY 9 Dec 1974 [7 Dec 1973] 53181/74 Heading E1G A screeding appliance includes an elongate frame having three mounting points 10, 14 for attachment to a tractors lift linkage so that the frames longitudinal axis is parallel wih that of the tractor and a screed board support 22 for supporting a screed 23 transverse to said axis, the support 22 being reciprocable in said transverse direction by means of a lever 20 pivoted about a vertical axis 21, one end of the lever being pivoted at 38 to the support 22 and the other end being connected to reciprocating means operable by a tractors power-take-off shaft. The reciprocating means comprises a crank and pitman. The support 22 is also pivoted to arms 24 pivoted at 25 about a vertical axis The support 22 may also be vertically vibrated.

Description

This Invention concerns an appliance for screeding concrete with the aid of an agricultural tractor, for example in laying roads, paths, farmyard surfaces or foundations where it is required to spread a mix of concrete or similar material to provide a level surface.

In laying down a concrete road surface, for example, it is customary to set up gauge boards along each side of an area to be surfaced, the boards being parallel and spaced apart with the top edges thereof gauging the level of the surface desired, then to deposit a quantity of the concrete mix between the parallel boards, spreading it roughly with spades, and finally levelling 10 off the surface by placing a screed board transversely of the gauge boards and drawing the screed board therealong while reciprocating it longitudinally with the opposite end portions of the screed board sliding on the upper edges of the gauge boards. This operation is normally carried out manually and is very laborious, although machines of relatively expensive and complicated construct15 ion have been prepared for the specific purpose of laying (i.e. spreading and levelling) such surfaces.

The object of the invention is to provide a concrete screeding appliance of relatively simple construction for application to art agricultural tractor of conventional type, whereby the work of screeding such surfaces as above 2o mentioned can be carried out most expeditiously and effectively.

Accordingly, the present invention provides a concrete screeding appliance comprising a main frame having longitudinal and transverse axes and having three mounting points adapted for attachment to the three point lifting linkage of an agricultural tractor in such a manner that the longitudinal axis of the frame 25 will be substantially parallel to the longitudinal direction of the tractor, a subframe carried by the main frame and having a screed board support member to which a screed board may be attached in such a manner that the board will be suspended horizontally and transversely relative to the main frame, and means for reciprocating said screed board support member transversely relative to the main frame, said means comprising a lever pivoted about a substantially vertical axis, having one end pivotally connected to said screed board support member and the other end operatively linked to reciprocating means adapted to be drivable from the power take-off shaft of a tractor when the appliance is attached thereto Normally the appliance is mounted behind the tractor and the frame portion lo for suspending the screed board extends rearwardly, that is away from the body of the tractor. The appliance may be modified if desired in order to adapt it for mounting in front of the tractor, as is the case with various known tractormounted appliances.

In one of the preferred embodiments, the oscillating lever may be directly 15 connected to a pitman, and the driving means therefor may be similar to that commonly used to drive the cutter bar of a mowing attachment for tractor operation, i.e. a centrally mounted driving sprocket adapted to be coupled to the power take-off shaft of the tractor, and spaced laterally therefrom, but in the same transverse plane, a sprocket pinion adapted to be driven by chain from the driving sprocket wheel and having an eccentric or crank for the big end of the pitman.

Alternatively the oscillating lever may be linked by interconnected levers to a pitman driven by a crank mounted on a centrally mounted shaft adapted to be directly coupled to the power take-off of the tractor.

One embodiment of the invention is illustrated in the accompanying drawings in which: Fig, 1 is a plan view of the appliance, Fig. 2 is a sectional view on the line A - A of Fig. 1, Fig. 3 is a sectional view on the line B - B of Fig. 1 but showing the reciprocating mechanism in a different, position.

As shown in the drawings, the appliance comprises a main frame 1 and a subframe 2 mounted beneath it. The main frame 1 comprises horizontal longi5 tudinal members 3, 4 and transverse members 5, 6, 7, 8, all of square-section steel and all rigidly secured together in a rectangular framework. The longitudinal members 3, 4 have front arms 9, projecting beyond transverse member 5 for atta hment at 10 to the lower lifting links of the three-point hydraulic lifting system of the tractor. The frame 1 is braced by two upstanding inclined bridging members Tl and a third central inclined member 12 rising from transverse member 7 to meet the bridging members 11. The third member 12 is omitted from Fig. 3 for reasons of clarity. Beyond the junction, a bifurcated limb 13 extends forwardly for attachment at 14 to the top link of the hydraulic lifting system of the tractor.

Between transverse members 6 and 7, there are downwardly extending plates to which the subframe 2 is pivotally attached. The subframe 2 is based on a transverse member 16 made up of two flat bars spaced one above the other and joined at both ends by brackets. Pivot pins 17 connect the brackets to the plates T5 so that the transverse member is pivoted on a transverse horizontal axis. Obviously it would be equally suitable to have the pivots in line with the main frame and replace the plates 15 with trailing arms suspended from the pivots. Further superimposed pairs of flat bars 18, 19 form a V-shaped framework which is rigidly secured at its feet to the transverse member 16 and which has its apex extending rearwardly from the transverse member 16. The slots between tne pairs of flat bars house a substantially horizontal lever 20 which of its ends is pivoted intermediately/about a vertical pivot 21 located at the apex of the V-shaped framework. The lever 20 is therefore capable of swinging to and fro in a substantially horizontal plane about the pivot 21. One end of the lover 20 extends forwardly through the transverse member 1θ and is operatively linked to reciprocating means (to be described below). The other end of the lever 20 is hinged on a vertical pivot 38 at the middle of an angle iron 22 which carries a screed board 23 attached to brackets depending from the angle iron. The pivot 38 is at the middle of the screed board 23 and the board lies horizontally on edge in a transverse direction with respect to the appliance.

Two side arms 24 are hinged at one end on vertical pivots 25 at the ends of the transverse member 16 and are hinged at the other end on vertical pivots 40 on the angle iron 22, the pivots 40 being suitably spaced apart on opposite sides of the centre pivot 38. The distance between the pivots 40 is slightly greater than that between pivots 25, but the two arms 24 with the transverse member 16 and the angle iron 22 form a shape comparable to a parallelogram.

The arms 24 keep the screed board parallel to the transverse member 16 as it reciprocates in response to movements of the lever. Two chains 39 entend between the ends of the angle iron 22 and the rear ends of the two longitudinal members 3, 4 of the main frame. The chains 39 lift the screed hoard when the appliance is raised by the lifting gear of the tractor. If desired the main frame may be provided with legs or wheels (not shown) which may be positioned to support the frame when lowered.

The drive means comprise a central shaft 26 journalled in bearings housed in blocks built up on the transverse members 5 and 6 of the main frame. The shaft 26 is adapted to be coupled through a universal coupling to the power take-off of the tractor. The rear end of shaft 26 carries a crank 27 having a wrist to which a pitman 29 is connected. The pitman 29 extends transversely towards the longitudinal frame member 3. The outer end 30 of the pitman is bifurcated and receives the upper end of a first link 31 which is connected to the pitman by a horizontal pivot 32. The first link 31 is pivoted intermediately on a horizontal pivot 33 mounted between a pair of plates fixed on the inner face of longitudinal member 3, the lower end of first link 31 is connected by a horizontal pivot 34 to the bifurcated outer end of a second link which extends inwardly to meet the front end of the oscillating lever 20 of the subframe. Second link 35 is connected to the lever 20 by means of a ball joint or universal joint 36. '' Rotation of the Shaft 26 (at a speed of about 100 r.p.m., for example) results in reciprocation of the pitman 29 and this reciprocating movement is transmitted via links 31 and 35 to the front end of the lever 20. The lever swings to and fro in a horizontal plane about pivot 21 and transmits the reciprocating movement to the screed board 23 which moves back and forth as indi10 cated by arrow 37. The side arms 24 move generally in parallel with the lever .

If desired, a vibrator (not shown in the drawings) may be mounted on the angle iron 22 so as to vibrate the screeo board up and down while it is being reciprocated transversely. For example, a simple form of vibrator may be (5 operated hydraulically through flexible hose extending along the main frame 1 from the tractor. Rotation of a shaft with an eccentric weight mounted thereon results in a vibratory movement which is transmitted to the screed board.

In one embodiment of the invention, the main frame is about 6 ft. (1.8 m) long and about 2 ft. 6 in. (0.76 m) wide. The screed board may usefully be about 12 ft. (3.6 m) long.

When it is desired to use the appliance to screed a surface to be laid, a quantity of the concrete mix is deposited between the gauge boards defining the sidps of the area in question, and is roughly spread in customary manner.

The tractor with the screeding appliance mounted thereon is backed into position (the appliance being raised by the Lifting links of the tractor) whereby, on lowering the lifting links the screed board will be dropped behind the concrete to be levelled, the screed board being positioned so that it rests under its own weight with the ends upon the gauge boards where the surface has previously been levelled off. The power take-off is then set into operation so as to cause 30 the screed board to be reciprocated and the vibrator (ir fitted) is set into operation while the tractor is moved slowly forward (i.e. away from the concrete to be levelled). This action will cause the screed board to spread and level the concrete in substantially the same manner as normally accomplished by manual operation. The speed of operation with the aid of the appliance is, however, greatly increased and the amount of manual labour required to lay and level a given surface greatly reduced in comparison with the normal manual procedure.

Claims (7)

1. A concrete screeding appliance comprising a main frame’having longitudinal 10 and transverse axes and having three mounting points adapted for attachment to the three point lifting linkage of an agricultural tractor in such a manner that the longitudinal axis of the frame will be substantially parallel to the longitudinal direction of the tractor, a subframe carried by the main frame and having a screed board support member to which a screed board may be attached in such a 15 manner that the board will be suspended horizontally and transversely relative to the main frame, and means for reciprocating said screed board support member trans versely relative to the main frame, said means comprising a lever pivoted about a substantially vertical axis, having one end pivotally connected to said screed board support member and the other end operatively linked to reciprocating means 20 adapted to be drivable from the power take-off shaft of a tractor when the appliance is attached thereto.

2. An appliance according to claim 1, wherein the said other end of the lever is operatively linked to a pitman which is drivable from a tractor power take-off shaft. 25

3. An appliance according to either of the preceding claims, wherein the subframe is pivotally mounted about a horizontal axis beneath the main frame.

4. An appliance according to any of the preceding claims, wherein the subframe comprises a main transverse member suspended from the main frame, the aforesaid screed board support member which lies parallel to the main transverse member, and two side arms each hinged at one end about a vertical pivot to the main transverse member and each hinged at the other end about a vertical pivot to the screed board support member.

5. An appliance according to claim 4, wherein the subframe further.comprises a 5 lever-housing framework rigidly secured to the main transverse member and having a vertical pivot on which the aforesaid lever is mounted.

6. An appliance according>to any of the preceding claims having a vibrator mounted thereon for vibrating the screed board support member during its reciprocating movements. ·

7. 10 7. A concrete screeding appliance substantially as described herein with reference to the accompanying drawings.