Patent Publication Number: US-2003230065-A1

Title: Clutch engagable, in-line, lawn trimmer attachment

Description:
BACKGROUND OF THE INVENTION  
       [0001] INCORPORATION BY REFERENCE: Applicant(s) hereby incorporate herein by reference, any and all U.S. patents, U.S. patent applications, and other documents and printed matter cited or referred to in this application.  
       FIELD OF THE INVENTION  
       [0002] This invention relates generally to lawn trimming devices and more particularly to an in-line lawn trimming attachment with power takeoff from a lawn mower driven shaft and featuring a clutch for engagement and disengagement of the trimmer.  
       DESCRIPTION OF RELATED ART  
       [0003] The following art defines the present state of this field:  
       [0004] Tihonovich, U.S. Pat. No. Des. 359,291 describes a mower with line weeder/trimmer attachment design.  
       [0005] True, U.S. Pat. No. 2,771,730 describes a lawn mower and trimmer which comprises, in combination, a wheeled carriage having at least one inset leading wheel, an elongated blade rotatably mounted under said carriage in grass-cutting relationship to cut a swath through a lawn, an elongated rotatable pivoted arm mounted laterally on said carriage on the side of said inset leading wheel, said rotatable pivoted arm being provided with means for rotating said rotatable pivoted arm about its longitudinal axis, a rotatable trimmer blade carried on said pivoted arm adjacent the inset wheel in advance of said elongated blade, power means mounted on said carriage in spaced apart relationship from said elongated blade for rotating said blades, a first belt operatively connecting said power means to said elongated blade, a second belt operatively connecting said power means to said trimmer blade, means connected to said pivoted arm for pivoting said pivoted arm upwardly in a vertical plane to loosen said second belt and disengage said trimmer blade from said power means, guide means on said carriage in operative relationship with said second belt for maintaining said second belt in operative connection with said power means comprising a roller under said second belt and a guide member above said second belt an idler pulley mounted on said carriage in rotatable contact with said first belt for maintaining said first belt in tension for rotating said elongated blade, and means connected to said idler pulley for moving said idler pulley into and out of contact with said first belt, said blades cutting a substantially continuous swath of a width greater than the width of the swath cut by said elongated blade when said trimmer blade is trimming and edging simultaneously in a common horizontal plane with the rotating elongated blade by rotating said pivoted arm about its longitudinal axis to place the trimming blade in said horizontal plane.  
       [0006] Gates, U.S. Pat. No. 5,065,566 describes a flexible line trimmer attachment for a tractor driven mower deck for trimming around trees and other objects simultaneously with mowing. A pivotal boom projects laterally from the mower deck and carries one or more trimming heads which rotate flexible lines using motive power supplied by the tractor. The boom deflects when it encounters a tree and is able to trim around more than 180.degree. of the tree circumference. A tension spring returns the boom to its normal lateral position after the tree has been cleared. The boom can be swung upwardly for compact storage by a power cylinder.  
       [0007] Wassenberg, U.S. Pat. No. 5,174,100 describes a combination mower/trimmer apparatus comprising a mower with a body, a driven horizontally oriented blade member, and a trimmer assembly. The trimmer assembly includes a pair of spools for dispensing flexible trimming lines, guides for directing the lines along the blade member, an activating assembly for extending and retracting the trimming lines, and a line for feeding assembly to supply additional line during use. The apparatus includes a pair of pivotally mounted guards which normally seek an elevated position but which assume a lowered position when the respective guard is urged against an obstacle whereby a generally horizontal elongate slot in that guard aligns with a similar slot in the mower body such that extended trimming lines simultaneously trim vegetation along the obstacle as the blade member mows the vegetation adjacent thereto.  
       [0008] Devillier et al., U.S. Pat. No. 5,560,189 describes a mower assembly for cutting, trimming, and edging a lawn. The inventive device includes a mower assembly hainv a blade rotating within a horizontal plane for cutting grass. A trimmer assembly extends laterally of the mower assembly for trimming grass. An edger assembly similarly projects laterally of the mower assembly and includes an edging blade rotating in a vertical plane for cutting grass adjacent a solid object.  
       [0009] Fassauer, EP 0514209 A1 describes an air-floated apparatus for use as a lawn mower or vacuum cleaner. In one embodiment, the apparatus comprises a housing having an outer shroud and an inner shroud, the outer shroud surrounding a predetermined portion of the inner shroud to define a pressure chamber between the inner and outer shrouds and a vacuum chamber within the inner shroud. A drive mechanism includes a motor having a rotatable shaft. A single impeller is supported in the pressure chamber and rotates on the shaft for exhausting air from the vacuum chamber to erect grass underlying the opening while simultaneously pressurizing air in the pressure chamber to float the apparatus above the grass. Airborne cut grass clippings are vacuumed into and through the impeller for distribution into the soil for recycle and recut. According to the invention, an adjustment assembly is provided for adjusting a position of the housing relative to a center-line auxiliary wheel assembly. The air-floated wheeled apparatus may include an edger and a trimmer. The prior art teaches lawn edgers and trimmers mounted on lawn mowers including attachments for existing lawn mowers, but does not teach an attachment with a simplified clutch arrangement as taught in the present invention. The present invention fulfills these needs and provides further related advantages as described in the following summary.  
       SUMMARY OF THE INVENTION  
       [0010] The present invention teaches certain benefits in construction and use which give rise to the objectives described below.  
       [0011] A string-type trimmer apparatus for a lawn mower uses a drive sprocket mounted on the lawn mower cutting blade shaft and adapted for rotating a driven sprocket mounted on a trimmer shaft. The trimmer shaft is supported for rotation by a mounting bracket supported from one side of a housing of the lawn mower. The drive sprocket is engaged with the driven sprocket by a rotational motion transfer device. A string trimmer head is engaged with a clutch adapted for moving the string trimmer head into and out of engagement with the trimmer shaft, so that the string trimmer head may be engaged for rotation with the driven sprocket.  
       [0012] A primary objective of the present invention is to provide an apparatus and method of use of such apparatus that provides advantages not taught by the prior art.  
       [0013] Another objective is to provide such an invention capable of being mounted onto a lawn mower for trimming and edging a lawn.  
       [0014] A further objective is to provide such an invention capable of being engaged and disengaged at will through a manually operated and simplified clutch arrangement.  
       [0015] Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0016] The accompanying drawings illustrate the present invention. In such drawings:  
     [0017]FIG. 1 is a perspective view of the preferred embodiment of the invention showing a trimmer device of the invention at one side of a lawn mower;  
     [0018]FIG. 2 is a perspective view thereof showing drive and driven sprockets of the invention and means for rotational motion transfer as a drive belt;  
     [0019]FIG. 3 is an exploded view of a trimmer drive and clutch thereof, and  
     [0020]FIG. 4 is an exploded view of a further embodiment thereof showing the motion transfer means as a drive shaft. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0021] The above described drawing figures illustrate the invention in at least one of its preferred embodiments, which is further defined in detail in the following description.  
     [0022] The present invention is a lawn maintenance apparatus comprising in combination: a lawn mower  10 , having a drive sprocket  20  mounted on the lawn mower&#39;s cutting blade shaft  25 , which is powered in rotational motion by the mower&#39;s engine  15 , and rotates with it. A driven sprocket  30  is mounted on a trimmer shaft  40 , which is held in place for rotation in upper bearing  84 ′. The upper bearing  84 ′ is supported for rotation and is mounted within a bearing housing  89 , onto a mounting bracket  50  engaging and extending from a housing  60  of the lawn mower  10 . These parts are engaged and assembled using common hardware as is shown and well known. The drive sprocket  20  is engaged with the driven sprocket  30  by a means for rotational motion transfer  70 , and a string trimmer head  80  is engaged with a clutch  90  adapted for moving the string trimmer head  80  into and out of engagement with the driven sprocket  30 . In this manner the string trimmer head  80  may be engaged for rotation with the driven sprocket  30  for spinning stings  83 , as well as disengaged when desired.  
     [0023] The motion transfer means  70  is preferably a drive belt, as shown in FIGS. 2 and 3, or a shaft assembly, as shown in FIG. 4. Such a shaft assembly preferably comprises small sprockets  74 , which engage sprockets  20 ′ and  30 ′ and which are rotationally engaged at the ends of  10  drive shaft  72 . Tube mount  76  is secured to mounting bracket  50  using fasteners  77  and  78  and drive shaft  72  is securely held by, and rotates, within it thereby providing an alternate manner of transferring rotational energy from shaft  25  to shaft  40 .  
     [0024] Preferably, the clutch  90  comprises a clutch pad  92  sandwiched between opposing surfaces  94  and  96 . In FIG. 3 the surfaces  94  and  96  are part of clutch plates  94 ′ and  96 ′. In FIG. 4, sprocket  30 ′ acts as one of the clutch plates. The clutch plates are able to be drawn toward each other and into contact on opposing sides of clutch pad  92  to enable the string trimmer head  80  to rotating with trimmer shaft  40  without interrupting lawn mowing action provided by cutting blade  28 . Referring now to FIG. 3, preferably, a flexible coaxial cable  82 , such as is used commonly for bicycle brakes, is engaged with the string trimmer head  80  and is adapted for drawing the head  80 , head engagement plate  81 , which is secured to head  80 , bearing  84 , clutch plate  94 ′ and clutch pad  92 , into contact with clutch plate  96 ′, which is mounted to driven sprocket  30 , the opposing surfaces  94  and  96  acting frictionally on clutch pad  92  for bringing head  80  into rotation. It should be noticed that trimmer shaft  40  rotates constantly, but head  80  may be rotating or not depending upon selection by the operator through an operating control means  14  mounted on a handle  12  of the lawn mower  10  as shown in FIG. 1. The control means  14  may be a simple lever or caliper as is known in the art.  
     [0025] While the invention has been described with reference to at least one preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims.