AU596452B2

AU596452B2 - Improvements in concrete trowelling machines

Info

Publication number: AU596452B2
Application number: AU79920/87A
Authority: AU
Inventors: Albert Pulie
Original assignee: PULIE Pty Ltd AG
Current assignee: AG PULIE PTY Ltd
Priority date: 1986-11-06
Filing date: 1987-10-19
Publication date: 1990-05-03
Anticipated expiration: 2007-10-19
Also published as: AU7992087A

Description

596452 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged; Complete Specification-Lodged Accepted: Published: 'riority: Tils document contains ihe amendments made& Linder Section 49 and is correct for sprinting.

L00G,4.f) AT' SWD OJFPIC 1 9 P.T11 4 '"ated Art: FE _SAif_

'ATTACHED

MAIL OFF CER]\ ne ofApiat esne of Applicant: TO BE COMPLETED BY APPLICANT A.G.PTJLIE PTY. LIMITED 21 Kendall Street, Granville$ N.S.W.9 Australia.

0, 4 41 Inventor: Albert PUIJIE /Agaress for Service: HAILLIDAYS, Patent Attorneys, of '-14 Ashley Street, Hornsby, 2077, New South Wales, Aust, Complete Specification for tho invention entitle(!, The following statement Is a full doscription of this invention, Includin phubs.r r ofproming it known to me-. LODGED ATr U.:)FC CONCRETE TROWEL 1

ING

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2 This invention relates to powered concrete trowelling machines of the type which include a vertical rotating shaft with a number of trowelling blades fixed to arms radiating from the shaft.

In machines of the above type it is common to include blade tilting means so that the angle of attack of the blade surface to the surface of the concrete area being trowelled can be varied. As can be imagined the working conditions for concrete trowelling machines are very severe. It has long been the objective of machine manufacturers to produce machines where adjustments of blade angle and other operating adjustments can be carried out efficiently by mechanisms which would be effected minimally by water and accumulations of cement and the abra ive effects of aggregate and sand.

4P Several attempts have been made to provide such mechanisms, ,for example, the blade angle adjustment mechanism has been ,,,enclosed. These attempts have been moderately successful but to this time no simple and effective enclosed adjustment

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mechanism has been devised.

This invention provides such a mechanism and broadly it can be said to be a concrete trowelling machine comprising a power unit with a rotating output shaft which is normally vertical when in use, a \fixed to the output shaft to

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-3rotate therewith, a chamber within the housing, a control rod access opening into said chamber through a wall of the housing and aligned with an axial bore throu-'! said output shaft, a plurality of blade shafts mounted in the housing for partial rotation and extending beyond the housing with the axes of part rotation of the shafts in a common plane which is at right angles to the axis of the output shaft bore, a trowelling blade assembly fixed to each blade shaft external of said housing, means to rotate the blade shafts in unison and thereby uniformly vary the planar relationship of trowelling surfaces of blade parts of the trowelling blade assemblies relative to a trowelling plane which lies at right angles to the axis of the output shaft, said blade shaft rotating means comprising an action plate disposed within said chamber and connected through a control rod passing through said output shaft bore to means to axially 4 ~move said rod and the action plate connected thereto,\~.

imers on each of said blade shafts which extends laterally therefrom and extends Into said chamber for co-operation with said action plate whereby part rotational movement of the blade shafts Is achieved by raising and lowering said action plate.

A preferred embodiment of the invention will now be 4 9, described with reference to the drawings herewith in which:- Fig. I is a schematic illustration of a trowelling machine In accordance with the present invention, Fig. 2 Is an exploded perspective view of a blade assembly for the machine of Fig. 1, S Fig. 3 is a sectional elevation through a blade supporting 4 hub member of the machine, Fig.4 is a sectional plan view of the hub member below the section line 4-4 of Fig.g. and is a view of the special fastening bolt use in the invention.

In Fig.l there is shown a motor gearbox unit 1 (shown diagrammatically), utilising for preference a small capacity I.C. engine, with the motor output shaft coupled to the I ^input shaft of a gearbox, which is preferably of worm and .:10 worm wheel type. There is a handle assembly 2 fixed to the 0*04 0 q e0r'\ o \O"o A\V 0 o motor gearbox unit 1 and there is a hub member\3 fixed to o, the output shaft 4 of the gearbox.

4 o 4 Extending from the motor unit 1 there are four arms 5 which 0 4 support a guard ring 6 to maintain the trowelling machine at 4 4 Sa predetermined distance from walls or the like surrounding an area of concrete being trowelled. To this point the I* present machine varies little from known machines.

444, Extending radially from the hub member 3 there are four shafts 7. On each shaft 7 there is fixed a blade assembly comprised of a housing 8 with an attached blade 9.

The present invention is primarily concerned with the manner 9 of mounting the blades -hand adjusting the attack angle of the blades 9 in a trowelling operation. Fig.2 .!hows each P Li.: ~/,4b 5 shaft 7 with a laterally projecting peg 10 adjacent one end and at its other end there is a central threaded hole 11 and a chamfer 12. Although not very clear from Fig.2 the chamfer 12 is in a plane which is at two angles to the axis of the peg 10 for reasons that will be clear from the following description. Each shaft '7 is for insertion into the bore 13 of a housing 8 to which a blade 9 is coupled by screws 14 of a special type to be described. There is a hole 15 in the housing 8 which intersects the housing bore 13 adjacent its bottom, for reasons to be explained.

The configuration of the housing 3 is as shown in Figs.3 and 4 and comprises an iron casting with four holes 16 which intersect as shown in Fig.4 each adapted to receive the peg end of a shaft 7 with the pegs 10 resting in notches 17, one such arrangement is shown in Fig.4. The shafts 7 can rotate partially within' the limits imposed by the pegs 10 and the notches 17. The pegs 10 are inserted into the shafts 7 after mounting in the kub holes 16 and serve to retain the blade shafts in the hub in accurate location by interaction between the pegs 10 and the notches 17.

The housings 8 are each retained on a shaft 7 in correct rotational position by engagement of the chamfer 12 with the pin 18 in the hole 15. The engagement is enforced by the bolt 19 engaging in the shaft threaded hole 11 with the bolt head 20 bearing against the end of the housing 8. It will it I t I Ir Iii' a Ir tr Itl r I t 00i uamra~ 6 be noted from Fig.3 that the longitudinal axis of the peg is at a depressed angle of about 15 to 20 degrees to the plane of the axis of the pin 18 so that when the peg 10 is moved to horizontal the blade 9 will have a heel down orientation with the plane of the blade 9 at an angle of to 20 degrees to the horizontal.

There is a counterbore 21 in the top of the housing 3 to receive a flange 22 on the end of the geaEi\output shaft 4 which is tubular. The flange 22 is bolted in suitable tt 10 manner to the housing 3. There is a counterbore 23 on the S: bottom of the housing 3 to receive a cover plate 24.

Mounted within the housing 3 there is a square action plate which lies in a square aperture 26 in the housing 3 and a 1 shaft 27 fixed to the action plate 25 projects through the *r shaft 4 to emerge above the gearbox portion of the motor gearbox unit 1. It is to be noted that the motor is spaced from the top of the gearbox 1. The action plate 25 when Sr raised will engage the free ends of the pegs 10 and raise them with resultant rotation of the shafts 7 causing the blades 9 to adopt a required trowelling angle at determined by the degree of elevation of the action plate Raising of the shaft 27 with its attached action plate can be achieved in anyone of fj number of ways as could be readily devised by a person skilled in engineering. In the f'SLtx

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i i I~C 7 presently preferred manner the shaft 27 has a cap and thrust bearing assembly 28 fixed to the top of the shaft 27. A forked member 29 pivotted at 30 to the top of the assembly 1 lies below the assembly 28. The free end 31 of the forked member 29 is connected by a rod or cable 32 to a hand controlled adjustment means 33 on the machine handle 2.

The angle of attack of the blades 9 can be readily adjusted from the machine handle 2 and as required by the invention the means for effecting the adjustment in the housing 3 are 10 secure from exposure to the working enviroment.

'r The present invention by adopting the robust housing 8 and a large diameter for the shaft 7 provides rigidity for the blades. It is simple to remove the blades 9, by removing *4 the screws 19, thereby allowing ready replacement of the blades 9 when worn. The construction makes it possible for A. the first time in concrete trowelling machines to have a 4 replaceable trowelling blade which is a simple pressing without ridges and other reinforcements, as are required 4, with trowelling blades used in known trowelling machines.

14 In the presently preferred form the t44-- for mounting the blade 9 are of tapered-square configuration at the head.

Referring to Fig.5 it will be seen that the bolt has a threaded shank 34, a square sectioned collar 35 and a head 36 of frusto-conical shape. The square collar 35 and the 8 head 36 are housed in a correspondingly shaped hole 37 in the blade 9. The end of the head 36 will lie level with the undersurface of the blade 9 thereby minimising wear of the bolt head during the use of the trowelling machine and the square collar fits into a square section in the blade hole to prevent the bolt rotating as a nut is mounted thereon.

In a modification of the construction described above a thin rubber or like sleeve can be placed over the shaft 7 and lie within the bore 13 to cushion shocks suffered by the blades 10 during use of the machine.

Whilst four blades 9 each with an associated shaft 7 have been described a different number of shafts and blades can be used, for example three.

As described raising of the action plate 25 forces the trowelling surfaces, of the blades to adopt an angle to the horizontal and lowering of the action plate will allow the weight of the machine to return the blades to positions where they lie flat upon the surface being trowelled. It is however also possible to connect the pegs 10 to the action plate so that mo'rement of the action plate up and down will positively move the pegs up and down.

Claims

1. A concrete trowelling machine comprising a power unit with a rotating output shaft which is normally vertical when in use, a housing fixed to the output shaft to rotate therewith, a chamber within the housing, a control rod access opening into said chamber through a wall of the housing and aligned with an axial bore through said output shaft, a plurality of blade shafts mounted in the housing for partial rotation and extending beyond the housing with the axes of part rotation of the shafts in a common plane which is at right angles to the axis of the output shaft bore, a trowelling blade assembly fixed to each blade shaft external of said housing, means to rotate the blade shafts in unison and thereby uniformly vary the planar relationship of trowelling surfaces of blade parts of the trowelling 9I blade assemblies relative to a trowelling plane which lies at right angles to the axis of the output shaft, said blade shaft rotating means comprising an action plate disposed within said chamber and connected through a control rod passing through said output shaft bore to means to axially ".4020 move said rod and the action plate connected thereto,).*- 'moe& on each of said blade shafts which extends laterally therefrom and extends into said chamber for co-operation with said action plate whereby part rotational movement of thrs blade shafts is achieved by raising and lowering isald action plate. .uHiwW 10 10

2. A trowelling machine as claimed in claim 1 wherein the blade shafts are respectively mounted in bearing forming holes in the housing which do not intersect with said chamber, and a notch between each bearing forming hole and said chamber to allow said ak ej-meft\to extend into said chamber.

3. A trowelling machine as claimed in claim 1 or claim 2 wherein those portions of the kg-monA*N extending into the chamber for co-operation with the action plate are disposed above said action plate.

4. A trowelling machine as claimed in any one of claims 1 to 3 wherein each trowelling blade assembly comprises a I blade made of sheet material which is fixed directly to a blade support mounted on the liade shaft. A trowelling machine as claimed in 4 wherein each of said blade supports has a hole therethrough a portion of S, which from one end of the hole is adapted to receive I thereinto a free end of a blade shaft provided with a part which is angled relative to a plare at right angles to the Si blade shaft axis, said angled part being for engagement with a pin through the hole in the housing, and pressure applying means to provide said engagement and thereby to rotationally orient the blade shaft relative to the trowelling surface of the blade of the trowelling blade assembly.

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6. A trowelling machine as claimed in claim 5 wherein the pressure applying means comprises a screw engaged in an axial threaded hole in the free end of the blade shaft and a head which bears on the blade support around the other end of said hole therein.

7. A trowelling machine as claimed in any one of claims 1 to 6 including handle means and control means on the handle means whereby said control rod can be moved axially to cause part rotational movement of said blade shafts.

8. A trowelling machine as claimed in any one of claims I to 7 including a trowelling blade guard ring concentric with said output shaft and within which said trowelling blades t Ir travel in a trowelling rotation of said housing,

9. A trowelling machine as hereinbewfore described with reference to the accompanying drawings. Dated this 17th day of October, 1989, A.G. PULIE PTY. LIMITED 4 By its Patent Attorneys Hallidays N 4 044444