1. Field of the Invention
The invention relates generally to concrete finishing trowels and, more particularly, to a transport system for a powered finishing trowel. The invention additionally relates to a concrete finishing trowel, such as a riding trowel, having a transport system that allows unassisted manual movement of the trowel.
2. Description of the Related Art
A variety of machines are available for smoothing or otherwise finishing wet concrete. These machines range from simple hand trowels, to walk-behind trowels, to self-propelled riding trowels. Regardless of the mode of operation of such trowels, the powered trowels generally include one to three rotors that rotate relative to the concrete surface.
Riding concrete finishing trowels can finish large sections of concrete more rapidly and efficiently than manually pushed or guided hand-held or walk behind finishing trowels. Riding concrete finishing trowels typically include a frame having a cage that generally encloses two, and sometimes three or more, rotor assemblies. Each rotor assembly includes a driven shaft and a plurality of trowel blades mounted on and extending radially outwardly from the bottom end of the driven shaft. The driven shafts of the rotor assemblies are driven by one or more engines mounted on the frame and typically linked to the driven shafts by gearboxes of the respective rotor assemblies.
The weight of the finishing trowel, including the operator, is transmitted frictionally to the concrete surface by the rotating blades, thereby smoothing the concrete surface. The pitch of individual blades can be altered relative to the driven shafts via operation of a lever and/or linkage system during use of the machine. Such a construction allows the operator to adjust blade pitch during operation of the power trowel. As commonly understood, blade pitch adjustment alters the pressure applied to the surface being finished by the machine. This blade pitch adjustment permits the finishing characteristics of the machine to be adjusted. For instance, in an ideal finishing operation, the operator first performs an initial “floating” operation in which the blades are operated at low speeds (on the order of about 30 rpm) but at high torque. Then, the concrete is allowed to cure for another 15 minutes to one-half hour, and the machine is operated at progressively increasing speeds and progressively increasing blade pitches up to the performance of a finishing or “burning” operation at the highest possible speed—preferably above about 150 rpm and up to about 200 rpm.
During use, the riding trowel is supported by the engagement between the number of blades and the underlying concrete material. To some extent, the weight of the machine assists the finishing process. Although the weight of the machine can be beneficial for providing efficient, robust, and powerful trowel operation, the weight of the machine is also detrimental to non-use transportation of the trowel, i.e. while moving the trowel to or from a worksite without operating the blades. Commonly, supplemental equipment, such as a skid loader, a backhoe, or the like, is utilized to move the machine to and from a work surface. Some concrete finishing trowels are fitted with lift points for attachment to a chain for this purpose. Alternatively, when no such equipment is available or the trowel must be used in a location which is not accessible by such equipment, two or more laborers are required to manually lift and move the machine. This is a labor some and physically demanding means of moving such machines.
Previous trowel transport systems have been disclosed which include a number of retractable wheels or casters that are securable to the frame of the trowel. One such system is a removable wheel kit or dolly disclosed in U.S. Pat. No. 5,238,323 to Allen et al. The wheel kit disclosed in the Allen '323 patent includes a pair of wheel assemblies secured to generally opposite sides of the exterior of the cage of a riding trowel. A separate jack is provided for each wheel assembly so that each jack independently raises and lowers a separate wheel assembly relative to the frame. When lowered, the wheels support the trowel such that a single user can move the entire trowel by simply pushing or pulling it in an intended direction. Although such systems enhance the mobility of power trowels, they are not without their drawbacks.
For instance, because the wheel assemblies of the Allen '323 patent are located outboard of the cage, they increase the overall footprint of the machine. Increasing the footprint of the machine increases the space occupied by the machine. Accordingly, it may prevent the machine from being transported in the beds of some trucks without removing the wheel assemblies. Increasing the footprint of the machine also detracts from a user's ability to position the machine close to the perimeter of a pour area or an obstacle in a pour area. This is problematic because users of finishing machines prefer that the machine finishes as much of the work surface as possible to reduce the need for hand work. In enclosed spaces, the wheel assemblies disclosed in the '323 patent, being positioned outside a normal footprint of the machine, are exposed to the obstacles, such as walls, posts, or the like, and thus increase an offset between an outer edge of the machine and an outer edge of the area finished by the blades. The areas that cannot be finished due to the interference between the wheel assemblies and the obstructions must be finished by hand, increasing the amount of hand work associated with a given pour. This problem can be avoided only by removing the wheel assemblies prior to commencing a finishing operation.
Transport systems such as the one disclosed in U.S. Pat. No. 5,238,323 are also relatively inefficient. To raise the machine, the operator must operate two separate jacks on opposite sides of the machine. In addition, unless care is taken to operate both jacks the same amount, one side of the machine may be higher than the other during transport, reducing the stability and maneuverability of the machine.
Accordingly, there is also a need for a transport system for a concrete finishing trowel that requires less effort than previously-known transport systems to be converted between a stowed position and a deployed operational position. There is also a need for an easily deployed concrete finishing trowel transport system that does not unnecessarily increase the footprint of the machine. It is further desired to provide a trowel transport system that can be implemented into a number of machine configurations as well as one that is relatively simple to operate, inexpensive to produce, and simple to maintain.
The present invention provides a power concrete finishing trowel transport system that meets one or more of the above-identified needs. A transport system according to one aspect of the invention includes at least two of spaced wheels that are concurrently movable by manipulation of a single lifting jack to adjust the position of both of the wheels relative to the blades of the finishing machine.
Another aspect of the invention is to provide a power concrete finishing trowel that meets the first principal aspect and that is simple to operate, does not substantially increase the weight of the finishing machine, and inexpensive.
Yet another aspect of the invention is to provide a power concrete finishing trowel with a transport system that meets one or more of the first and second aspects and that does not otherwise increase the footprint of the finishing machine.
One or more of these aspects are achieved by a transport system for a riding power trowel having a plurality of blades that are supported for rotation relative to a frame of the power trowel. The transport system includes a first wheel and a second wheel that are connected by a connector such as a shaft. A single lift device such as a jack or cylinder is connected to the frame and the connector such that operation of the lift device retracts or deploys the wheels. Such a transport system reduces the amount of time required to configure a trowel for transport.
A concrete finishing trowel for satisfying one or more of these aspects includes a frame and rotor assembly that extends downwardly from the frame. The rotor assembly has a shaft that supports a plurality of blades. An engine drives the shaft of the rotor assembly to translate the blades across a concrete material. The trowel includes a transport assembly having a connector that extends between a first wheel and a second wheel. A single lift device is engaged with the transport assembly such that operation of the single lift device concurrently moves the first wheel and the second wheel relative to the frame.
A method for satisfying one or more of the above aspects includes providing a power trowel having a frame and at least one rotor assembly that includes a rotatable shaft and a plurality of blades. The method includes concurrently manipulating a position of more than one support, such as wheels, that defines a distance between the plurality of blades and a supporting surface by operation of a lift device. Such a method allows a user to quickly and efficiently raise a power trowel in a generally level fashion.
These and other aspects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof. It is hereby disclosed that the invention include all such modifications.
Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which:
Referring to
Referring to
Referring to
In the typical arrangement, a thrust collar (not shown) cooperates with a yoke 78 that is movable to force the thrust collar into a position pivoting trowel blades 62 about an axis extending perpendicular to the axis of the driven shaft 60. A tension cable 81 extends from the crank 74, through the post 72, and to the yoke 78 to interconnect the yoke 78 with the crank 74. Rotation of the crank 74 adjusts the yoke's angle to move the thrust collar 76 up or down thereby providing a desired degree of trowel blade pitch adjustment. The pitch of blades 62 is often varied as the material being finished sets and becomes more resistant to being worked by the blades. A power concrete finishing trowel having this type of blade pitch adjustment assembly is disclosed, e.g., in U.S. Pat. No. 2,887,934 to Whiteman, the disclosure of which is hereby incorporated by reference.
Both rotor assemblies 24 and 26, as well as other powered components of the finishing trowel 20, are driven by a power source such as internal combustion engine 42 mounted proximate or under operators seat 34. The size of engine 42 will vary with the size of the machine 20 and the number of rotor assemblies powered by the engine. The illustrated two-rotor 36″ machine typically will employ an engine of about 20-25 hp.
Referring to
In use, as is typical of riding concrete finishing trowels of this type, the machine 20 is steered by tilting a portion or all of each of the rotor assemblies 24 and 26 so that the rotation of the blades 62 generates horizontal forces that propel machine 20. The steering direction is generally perpendicular to the direction of rotor assembly tilt. Hence, side-to-side and fore-and-aft rotor assembly tilting cause machine 20 to move forward/reverse and left/right, respectively. The most expeditious way to effect the tilting required for steering control is by tilting the entire rotor assemblies 24 and 26, including the gearboxes 58. The discussion that follows therefore will describe a preferred embodiment in which the entire gearboxes 58 tilt, it being understood that the invention is equally applicable to systems in which other components of the rotor assemblies 24 and 26 are also tilted for steering control.
More specifically, the machine 20 is steered to move forward by tilting the gearboxes 58 laterally to increase the pressure on the inner blades of each rotor assembly 24, 26 and is steered to move backwards by tilting the gearboxes 58 laterally to increase the pressure on the outer blades of each rotor assembly 24, 26. Crab or side-to-side steering requires tilting of only one gearbox (the gearbox of the right rotor assembly 24 in the illustrated embodiment), with forward tilting of right rotor assembly 24 increasing the pressure on the front blades of the rotor assembly 24 to steer the machine 20 to the right. Similarly, rearward tilting of rotor assembly 24 increases the pressure on the back blades of the rotor assembly 24 thereby steering machine 20 to the left.
Steering system 22 tilts the gearboxes 58 of the right and left rotor assemblies 24, 26 in response to manipulation of handles 28, 30 by the operator. Handles 28, 30 are connected to gearboxes 58 such that translations of one or both handles 28, 30 tilt or otherwise manipulate the position of gearboxes 58 relative to frame 36. Tilting of the gearboxes effectuates movement of the machine through the frictional and gravitational forces associated with passage of blades 62 over a concrete surface. It is appreciated that operation of blades 62 over non-pliable concrete surfaces is detrimental to machine performance, can result in unintended and jerky movement of the machine, and may damage machine 20. Accordingly, non-use movement of machine 20 means translation of machine 20 without interference of blades 62 with an underlying or supporting surface, such as the ground.
Referring to
Each wheel assembly 80, 82 includes a wheel 83 that rotates about an axle 86. The axle 86 extends longitudinally of the machine 20 in the illustrated embodiment but, conceivably, could extend laterally or swivel. In fact, longitudinally extending axles would be preferred in a system in which the wheels are located at the sides of the machine 20 rather than at the front and rear. However, for multiple rotor machines that are wider than they are long, the illustrated longitudinally spaced wheels with coaxial longitudinal axles are preferred. In any event, the axial centerlines CL (
Each of the first and second wheel assemblies 80, 82 additionally includes a respective support 88, 96. First support 88 includes outer and inner spaced parallel arms 90 and 92 which support axle 86 at a location below an axis 94 of shaft 84. Second support 96 also includes an outer arm 98 and an inner arm 100 and offsets axle 86 of the wheel 83 of the second wheel assembly 82 below the axis 94 of shaft 84.
As shown in
Referring to
The wheel assemblies 80, 82 are movable by the jack 102 between a non-use or stowed orientation shown in solid lines in
Referring to
It is further appreciated that elevating trowel 20 with transport system 21 will also be beneficial for purposes other than transport. For instance, after a finishing operation, machine 20, including the underside of cage 32 and blades 62, must be cleaned to remove residual concrete materials from the machine. Transport system 21 can be deployed to elevate trowel 20 such that a user can quickly clean the underside of the machine. In addition, the wheel assemblies can be deployed to facilitate blade maintenance or replacement or to facilitate the installation of pans on the bottoms of the rotor assemblies.
Hence, the inventive system reduces operator effort to configure the riding trowel for non-assisted transportation, provides an efficient means of changing the elevation of the machine and does not adversely affect the footprint of the trowel.
It is appreciated that many changes and modifications could be made to the invention without departing from the spirit thereof. Some of these changes, such as its applicability to riding concrete finishing trowels having other than two rotors and even to other self-propelled powered finishing trowels, are discussed above. Other changes will become apparent from the appended claims. It is intended that all such changes and/or modifications be incorporated in the appending claims.
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4113403 | Tertinek et al. | Sep 1978 | A |
4710055 | Maass et al. | Dec 1987 | A |
5088799 | Redmon et al. | Feb 1992 | A |
5238323 | Allen et al. | Aug 1993 | A |
D340340 | Allen | Oct 1993 | S |
6059299 | Rust | May 2000 | A |
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D465897 | Smith | Nov 2002 | S |
D518070 | Schennach | Mar 2006 | S |
7204657 | Jackson | Apr 2007 | B2 |
Number | Date | Country | |
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20090047070 A1 | Feb 2009 | US |