WO2022182820A1

WO2022182820A1 - Concrete trowel

Info

Publication number: WO2022182820A1
Application number: PCT/US2022/017621
Authority: WO
Inventors: Ian C. RICHARDS
Original assignee: Milwaukee Electric Tool Corporation
Priority date: 2021-02-24
Filing date: 2022-02-24
Publication date: 2022-09-01
Also published as: US20220267968A1

Abstract

A concrete trowel is disclosed and includes a frame, a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor and a rotor rotatable about a rotational axis. The rotor includes a rotor hub coupled for corotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a plurality of blades selectively attached on respective rotor arms by a quick-connect mounting system.

Description

CONCRETE TROWEL

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to co-pending U.S. Provisional Patent Application No. 63/153,054 filed on February 24, 2021, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to powered concrete trowels, and more particularly to battery powered concrete finishing trowels.

BACKGROUND OF THE INVENTION

[0003] Powered concrete trowels are typically used for finishing concrete surfaces and generally include a gas-powered motor mounted on a frame or “cage” that surrounds a rotor having a plurality of concrete trowel blades. The rotor is rotatably driven by the motor, which rotates the blades on a concrete surface. The trowel is controlled by an operator via a handle extending from the cage. Most concrete trowels include a single set of rotating blades that are attached to radially spaced apart arms extending from the rotor via a plurality of fasteners, such as bolts. In most cases, these blades are combination blades having a leading edge that is pitched upward so that it doesn’t damage freshly laid concrete, and a trailing edge that is flat for finishing the concrete surface. During use, the trailing, or finishing edge, can incur a lot of wear due to repeatedly striking the concrete surface, which can cause unwanted burnish marks on the finished concrete surface. Typically, to avoid this burnishing, an operator would have to stop and either replace the trowel blade or hand finish the burnished surface. This is both time consuming and costly.

SUMMARY OF THE INVENTION

[0004] The present invention provides, in one aspect, a concrete trowel including a frame, a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor, and a rotor rotatable about a rotational axis. The rotor includes a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a plurality of blades selectively attached on respective rotor arms by a quick-connect mounting system.

[0005] The present invention provides, in another aspect, a concrete trowel including a frame, a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor, and a rotor rotatable about a rotational axis. The rotor includes a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a plurality of blades mounted on the plurality of rotor arms, each blade including a main blade body and a removable trailing edge portion.

[0006] In another aspect of the present invention, a concrete trowel is disclosed and includes a frame, a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor, a rotor rotatable about a rotational axis, the rotor including a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a multi-piece blade selectively attached to each of the rotor arms by a quick-connect mounting system. Each multi-piece blade includes a blade body and a removable trailing edge portion selectively attached to the blade body.

[0007] Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is perspective view of a concrete trowel according to an embodiment of the invention.

[0009] FIG. 2 is a side, partial cutaway view of the concrete trowel of FIG. 1.

[0010] FIG. 3 A is a top, schematic view of a rotor having a plurality of blades in accordance with an embodiment of the invention for use with the trowel of FIG. 1.

[0011] FIG. 3B is a cross-section view of a blade taken along line 3B-3B in FIG. 3 A.

[0012] FIG. 4A is side view of an alternative blade in accordance with an embodiment of the invention for use with the trowel of FIG. 1.

[0013] FIG. 4B is a top view of the blade of FIG. 4A. [0014] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

[0015] FIG. 1 illustrates a concrete trowel 10 including frame 12 having a blade guard

14 surrounding a rotor 18 having a plurality of blades 22, a drive assembly 26 mounted on the frame 12 having a motor 30 (e.g., a brushless direct current electric motor) with an output shaft 32 extending from the motor 30 (FIG. 2), and a gear box 38 coupled to the motor 30 having a drive hub 42. The drive assembly 26 is powered by a battery pack 46 supported by the frame 12 and in selective electrical communication with the motor 30 to provide electrical power to the motor 30. In some embodiments of the trowel 10, the battery pack 46 and the motor 30 can be configured as an 80 Volt high power battery pack 46 and motor 30, such as the 80 Volt battery pack and motor disclosed in U.S. Patent Application No. 16/025,491 filed on July 2, 2018 (now U.S. Patent Application Publication No. 2019/0006980), the entirety of which is incorporated herein by reference. It is to be understood that the motor 30 may be a combustion engine and in such a case, in lieu of a battery pack 46, the concrete trowel 10 may include a fuel cell and a fuel injection system, or carburetion system, in fluid communication with the motor 30.

[0016] With reference to FIGS. 1 and 2, the motor 30 is configured to supply torque to the drive hub 42 of the gear box 38 via the output shaft 32, rotatably driving the rotor 18 to rotate the plurality of blades 22. The concrete trowel 10 further includes a controller 50 (including, amongst other components, a printed circuit board having one or more microprocessors and multiple field-effect transducers for driving the motor 30), a blade adjustment yoke 54 pivotably coupled to the drive hub 42, and a handle assembly 58 including a post 62 extending obliquely from the blade guard 14 and handlebars 66 coupled to the post 62. The handle assembly 58 further includes an operator control unit 70 mounted on one of the handlebars 66 having a plurality of operator controls (e.g., an ON/OFF switch 71, a speed adjustment switch 73, etc.) for providing an input signal to the controller 50, and a blade pitch adjustment knob 74 having an adjustment cable 78 coupled to the blade adjustment yoke 54. The blade pitch adjustment knob 74 is configured to selectively tension the adjustment cable 78, thereby pivoting the adjustment yoke 54 with respect to the drive hub 42, which adjusts the pitch of the blades 22 relative to a work surface 33.

[0017] In some embodiments of the trowel 10, the drive assembly 26 can be a direct drive system where the output shaft 32 is directly connected to the drive hub 42 to rotatably drive the rotor 18.

[0018] With reference to FIGS. 1-3B, the rotor 18 also includes a centrally located rotor hub 82 that is coupled for co-rotation with the drive hub 42 and a plurality of arms 86 radially extending from the rotor hub 82 to which one of the blades 22 is mounted. Each of the blades 22 is a multi-piece blade that includes blade body 88 having a curved leading edge portion 90 that allows the blade 22 to slide over the concrete surface and a plurality of quick- connect mounting portions 98 (e.g., over-center cam locks, or other fasteners such as, bolts, screws, etc.) affixed, or otherwise attached, to the blade body 88 for selectively, or removably, mounting the blades 22 to their respective arms 86. Further each of the blades 22 includes a flat, removable trailing edge portion 94 for smoothing out the concrete surface.

The blade body 88 of each blade further includes a front longitudinal edge 100 coincident with the leading edge portion 90, an opposite, rear longitudinal edge 102 to which the trailing edge portion 94 is connectable, and a plurality of quick-connect couplings 106 (e.g., over center cam locks, ball detents, magnets, etc.) for selectively mounting the removable trailing edge portion 94 to each of the blade bodies 88 of the respective blades 22. The removable trailing edge portions 94 can be located along the rear longitudinal edge 102 of each of the blade bodies 88 of the respective blades 22 using a locating, or alignment, feature such as a tongue 106 and groove 108, locating dowels, a combination thereof, or any other conventional means known by someone having ordinary skill in the art. FIG. 3B shows the groove 108 formed on the removable trailing edge portion 94 and the tongue 106 formed on the blade body 88, but it is to be understood that these parts may be reversed such that the groove is formed on the blade body 88 and the tongue is formed on the removable trailing edge portion 94.

[0019] During operation of the trowel 10, when the removable trailing edge portion

94 of one of the blades 22 becomes undesirably worn, the operator releases the quick-connect couplings 106 on the selected blade 22, which allows the operator to remove the worn trailing edge portion 94 and replace it with a new trailing edge portion 94 to the same blade 22. The quick-connect couplings 106 are thereafter returned to a locked state to secure the new trailing edge portion 94 to the blade body 88 of the particular blade 22.

[0020] In some embodiments, the trowel blades 22 and removable trailing edge portions 94 can be made from any suitable material, for example, steel with or without additives, ceramic materials, or a combination thereof. In other embodiments, a coating may be applied to the trowel blades 22 and/or removable trailing edge portions 94 in order to reduce wear and corrosion.

[0021] FIGS. 4 A and 4B illustrate an alternative embodiment of a trowel blade 23 that can be mounted on the rotor arms 86. The trowel blade 23 is formed as continuous generally rectangular body including a curved leading edge portion 91 for gliding over the concrete surface and a flat, trailing edge portion 95 for smoothing the concrete surface. The trowel blade 23 further includes a quick-connect mounting system 99 to secure the blade 23 to a respective rotor arm 86, permitting the entire blade 23 to be quickly attached and removed from the rotor arm 86. In some embodiments, the quick-connect mounting system 99 is toolless (e.g., an over-center cam lock). In other embodiments, the quick-connect mounting system 99 can require the usage of tools, such as a wrench, screwdriver, etc.

[0022] Likewise, with the trowel blade 22 described above, the trowel blade 23 can be made from any suitable material, for example, steel with or without additives, ceramic materials, or a combination thereof, and each of these materials may include a coating that reduces wear and corrosion.

[0023] By having the high-wearing trailing edge portion 94 of the trowel blade 22 be replaceable, this eliminates the need for the operator to replace the entire blade 22 when only the trailing edge is worn. Additionally, by providing a quick-change and toolless connection between the trailing edge portion 94 and the remainder of the blade 23, the operators do not need any additional tools in order to replace the removable trailing edge portions 94, which can reduce the time required to perform a blade exchange for the trowel 10.

[0024] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. [0025] Various features of the invention are set forth in the following claims.

Claims

CLAIMS What is claimed is:

1. A concrete trowel comprising: a frame; a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor; a rotor rotatable about a rotational axis, the rotor including a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a plurality of blades selectively attached on respective rotor arms by a quick- connect mounting system.

2. The concrete trowel of claim 1, wherein the quick-connect mounting system comprises a plurality of mounting portions.

3. The concrete trowel of claim 2, wherein the plurality of mounting portions are over center cam locks.

4. The concrete trowel of claim 1, wherein each of the plurality of blades is a multi-piece blade.

5. The concrete trowel of claim 4, wherein each multi-piece blade includes a blade body having a curved leading edge portion and a removable trailing edge portion connected to the blade body.

6. The concrete trowel of claim 5, wherein each multi-piece blade further includes a quick-connect coupling for removably connecting the removable trailing edge portion to the blade body.

7. The concrete trowel of claim 6, wherein each multi-piece blade further includes an alignment feature for aligning the removable trailing edge portion on the blade body.

8. The concrete trowel of claim 1, wherein the motor is an electric motor, and wherein the concrete trowel further comprises a battery pack supported on the frame for supplying electrical power to the motor.

9. A concrete trowel comprising: a frame; a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor; a rotor rotatable about a rotational axis, the rotor including a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a plurality of blades mounted on the plurality of rotor arms, each blade including a blade body and a removable trailing edge portion.

10. The concrete trowel of claim 9, further comprising a quick-connect coupling for selectively attaching the removable trailing edge portion and the blade body.

11. The concrete trowel of claim 9, wherein the blade body of each of the blades further comprises: a curved leading edge including a front longitudinal edge coincident with a leading edge of the blade; a rear longitudinal edge opposite the front longitudinal edge to which the removable trailing edge portion is connectable; and an alignment feature for aligning the removable trailing edge portion along the rear longitudinal edge of the blade body.

12. The concrete trowel of claim 11, wherein the alignment feature includes a tongue and groove or locating dowels.

13. The concrete trowel of claim 10, wherein the quick-connect coupling includes an over-center cam lock, ball detents, or magnets.

14. The concrete trowel of claim 9, wherein the blade body and the removable trailing edge portion of each of the blades are made from steel, a ceramic material, or a combination thereof.

15. The concrete trowel of claim 10, wherein the motor is an electric motor, and wherein the concrete trowel further comprises a battery pack supported on the frame for supplying electrical power to the motor.

16. A concrete trowel comprising: a frame; a drive assembly including a motor mounted on the frame and a drive hub configured to receive torque from the motor; a rotor rotatable about a rotational axis, the rotor including a rotor hub coupled for co-rotation with the drive hub, a plurality of rotor arms radially extending from the rotor hub, and a multi-piece blade selectively attached to each of the rotor arms by a quick- connect mounting system, each multi-piece blade including a blade body and a removable trailing edge portion selectively attached to the blade body.

17. The concrete trowel of claim 16, wherein the quick-connect mounting system comprises a plurality of mounting portions affixed to the blade body of each multi-piece blade.

18. The concrete trowel of claim 17, wherein the plurality of mounting portions are over center cam locks.

19. The concrete trowel of claim 16, wherein each multi -piece blade further includes a plurality of quick-connect couplings for removably connecting the removable trailing edge portion to the blade body.

20. The concrete trowel of claim 16, wherein the blade body of each of the blades further comprises: a curved leading edge including a front longitudinal edge coincident with a leading edge of the blade; a rear longitudinal edge opposite the front longitudinal edge to which the removable trailing edge portion is connectable; and an alignment feature for aligning the removable trailing edge portion along the rear longitudinal edge of the blade body.

21. The concrete trowel of claim 20, wherein the alignment feature includes a tongue and groove, locating dowels, or a combination thereof.

22. The concrete trowel of claim 16, wherein the blade body and the removable trailing edge portion of each of the blades are made from steel, a ceramic material, or a combination thereof.

23. The concrete trowel of claim 16, wherein the motor is an electric motor, and wherein the concrete trowel further comprises a battery pack supported on the frame for supplying electrical power to the motor.