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Power take offRelated Patent Categories: Mining Or In Situ Disintegration Of Hard Material, Hard Material Disintegrating Machines, Floor-working, Rotary Cutter, Slot-type Cutter; E.g., Pavement SawPower take off description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060012238, Power take off. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This is a continuation of Ser. No. 10/100,502, filed Mar. 18, 2002, now U.S. Pat. No. 6,945,608, incorporated herein by reference. BACKGROUND OF THE INVENTIONS [0002] 1. Field of the Invention [0003] This relates to power take off assemblies, and saws using power take off assemblies, for example concrete and slab saws and self propelled saws. [0004] 2. Related Art [0005] Power saws typically include a motor, engine or other system for producing drive power, a saw blade or other cutting device and a support frame structure for supporting the engine and cutting blade. The power system may be an internal combustion engine, a hydraulic motor, an electric motor or the like. The power system can drive the cutting blade through a mechanical or hydraulic drive system, but a belt drive system is common. The size and dimensions of the saw will vary according to usage and application. [0006] For large projects, higher horsepower levels are desired for the saw. Higher horsepower allows the use of larger cutting blades, reduces cutting time and may provide higher cutting speeds. However, higher horsepower levels usually mean larger engines and often larger saw dimensions. Larger saws may also mean less maneuver ability. [0007] In some applications, structures may be such that access to an area for cutting may be limited. For example, in high-rise buildings, concrete floors and/or walls may be poured or installed on an ongoing basis, and detail work may come later. Access openings such as door ways, floor openings, and the like, as well as concrete openings for fixtures may be formed after concrete slabs and walls are poured and the concrete hardened. Similar work may also be done on other concrete projects after the concrete has hardened. However, the equipment to be used for cutting in those areas may be limited by such restrictions as access opening size, elevator size and the like. For example, door ways in buildings may be 32 inches in width, thereby limiting the width of the saw to less than 32 inches. Therefore, the amount of horsepower for a saw and other operating characteristics such as blade size and the like may be limited for a given application by such factors as access opening size and the like. [0008] Increasing the horsepower for a saw often results in a larger saw. The consequences of a larger saw may be most noticeable where the saw engine is oriented sideways relative to the forward direction of motion of the saw. In these saws, the engine crank shaft and the stub shaft attached to it extend sideways from the engine, and one or more drive belts couple the stub shaft sheave to a sheave for driving a saw blade shaft. If the engine is made larger, the width of the engine with the stub shaft typically increases, which may make the saw less maneuverable. Therefore, saw improvements may have undesirable consequences for some users. [0009] In saws with a belt drive for the saw blade, the sheave is typically mounted to and held on the stub shaft using a shaft key fitting into a longitudinal groove in the stub shaft and a corresponding groove in an internal surface of the sheave. The stub shaft, key and sheave are subjected to side loading by the belts during normal operation. The side loading and the rotation in turn produces a cyclical fatigue load on the stub shaft, often focused in the area of the shaft key. Such loads sometimes produce fatigue and sometimes fractures in the shaft, leading to drive failure. Increasing the saw horsepower produces more cyclical fatigue loads on the shaft and may increase the likelihood of shaft failure. SUMMARY OF THE INVENTIONS [0010] Apparatus and methods are described for providing a saw with a smaller profile. A saw and method of operation are also provided that would allow a higher horsepower engine with the same overall saw dimension as conventional saws, or even smaller. A saw and saw operating method are shown that separate the drive function for the saw output and the support function for the saw output, or reducing the load function of the stub shaft so the primary function of the stub shaft is to turn the output sheave. Additionally, a saw and operating method are further described that reduces cyclical fatigue on the rotating shaft, and that may also reduce load placed on the engine crank shaft. Engine operation and performance can be improved and made more reliable, engine horsepower can be increased without adversely affecting the overall size of the saw, and in some cases, the saw size can be reduced. [0011] In one example of an assembly described herein, a power takeoff assembly includes a drive element, in one example a stub shaft, for rotation with a rotating element. A stationary support supports an output element. The output element rotates with the drive element, for example while being supported by the stationary support. With such an arrangement, load on the rotating element can be reduced and applied more to the stationary support, and the loading is preferably fixed and non-movable for example when the output element is positioned on the stationary support. In such a configuration, the load bearing function and the drive function can be separated. In one example, the drive element may be a stub shaft attached to a fly wheel of an engine extending into a bearing supporting shaft mounted to an engine housing, and the output element rotates on the bearings. The output element can be coupled to the stub shaft through a coupling element. The output element is supported by the shaft mounted on engine housing, and is driven about the shaft by the stub shaft through the coupling element. [0012] In another example of a power takeoff assembly, a drive element rotates with a rotating element and a stationary support supports an output element that rotates with the drive element. The drive element and the stationary support preferably extend in the same direction, and in one preferred form they are co-axial. For example, the drive element can be a stub shaft and stationary support can be a hollow shaft supported by the engine housing with the stub shaft extending through the hollow shaft. The output element rotates on bearings on the hollow shaft and is driven by the stub shaft through a coupling element. [0013] In a further example described herein, a drive assembly and method has a rotating drive and a stationary support. An output element is supported by the stationary support and coupled to the rotatable drive so as to rotate about the stationary support. The output element also includes surfaces for receiving a flexible element to be driven by the output element. The drive assembly separates the drive function for the output element and the support function for the output element so the drive assembly is more reliable. In one example, the rotating drive can be a drive shaft such as a stub shaft and may be mounted to an engine fly wheel through a removable drive plate. The drive shaft can include splines for engaging a coupling element which in turn engages the output element. The stationary support in one example includes a hollow shaft into which the drive shaft extends and engages with the coupling element. The stationary support is preferably mounted to a housing or other stationary support structure so as to reliably support the output element. In the context of an engine, the housing may be the engine block, and the stationary support can be the hollow shaft mounted, fixed or otherwise supported by a fly wheel cover. In another example of a drive assembly and method, the drive assembly may be used for driving a saw blade or other cutting device. The output element may include one or more surfaces for receiving drive belts, which are then run around an input sheave for the saw blade. [0014] In an additional example of a method and apparatus described herein, a saw includes an engine with a rotatable output shaft and a support stationary relative to the engine. An output element is supported by the stationary support and rotates with the rotatable output shaft. A cutting blade is driven by the output element, for example through one or more drive belts or the like. In one such example, the stationary support can be a support shaft and the support shaft can be mounted to the engine block, or another portion of a stationary structure can be used to support the support shaft. The output element may be a sheave turning on bearings on the support shaft. [0015] In one method of providing a drive assembly, a rotating drive can drive an output element supported by a rotationally fixed support. The output element is then rotated by the rotating drive, which rotation is transferred to a work piece such as through drive belts or the like. The output element thereby rotates on a structure other than the rotating drive, thereby allowing the load on the output element to be supported by the fixed support rather than being applied to the rotating drive. This drive method can be used as a power takeoff, for example on saws, cutting devices and other apparatus. [0016] In another example of apparatus, a kit may be provided for assembling a power takeoff assembly onto a structure such as an engine, a saw or other machine. The kit may include an output support for supporting a rotatable output device, for example a sheave, and a coupling element for coupling the output device to a rotatable element, for example a stub shaft. The kit may also include the stub shaft itself, especially where the stub shaft may have engagement surfaces, such as for receiving the coupling element, different from the stub shaft on the original equipment. In one example, the output support is a hollow shaft into which the stub shaft extends. The output support can include a mounting plate, web or other mounting structure for mounting the output support to a non-rotatable structure, for example an engine block. The output support preferably includes bearings between the support and the output device so that the output device can rotate freely about the support once assembled. [0017] These and other structures and methods are described further in the following detailed description, with reference to the drawings, a brief description of which follows. BRIEF DESCRIPTION OF THE DRAWINGS [0018] FIG. 1 is a side elevation and partial cutaway view of a machine with a power takeoff assembly, in the form of a slab saw such as that with which the apparatus described herein can be used. [0019] FIG. 2 is a front elevation view and partial schematic of the saw of FIG. 1. [0020] FIG. 2A is a detail cutaway of the fly wheel assembly of FIG. 2. Continue reading about Power take off... Full patent description for Power take off Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Power take off patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Power take off or other areas of interest. ### Previous Patent Application: Retractor having vehicle sensitive sensor disabling mechanism Next Patent Application: Head for excavator mounted to power shovel Industry Class: Mining or in situ disintegration of hard material ### FreshPatents.com Support Thank you for viewing the Power take off patent info. 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