Abstract:
A two wheeled carriage for converting a string trimmer to a wheeled appliance. The carriage has an axle, two nine inch or greater wheels, and a clamp for retaining the string trimmer&#39;s shaft. A swivel joint enables the clamp to adjust angular orientation of the appliance relative to the carriage. A latch locks the swivel joint in one of several angular orientations. The clamp includes an adjustable, flexible grasping element for engaging shafts of different dimensions and configurations. A lever operated over-center arrangement closes the grasping element over the appliance shaft. The clamp optionally includes saddles for securing that shaft in a fixed perpendicular and non-intersecting angular relationship to the axle. An adjuster varies deviation of that shaft from the horizontal. The adjustment mechanism may be located either between the axle and the swivel joint or alternatively between the swivel joint and the clamp.

Description:
REFERENCE TO RELATED APPLICATION 
   This application is related to U.S. patent application Ser. No. 09/576,046 filed May 23, 2000, now abandoned. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a wheeled carriage for converting a hand held appliance to a wheeled equivalent. More specifically, the wheeled carriage is quickly mounted to and disconnected from the appliance, so that the appliance is readily utilized either on its own or in wheeled form. The invention is used as an adjunct for hand held appliances, such as string trimmers, which have elongate handles. The invention is useful to homeowners and others charged with responsibility for using appliances such as string trimmers in maintaining residential, commercial, industrial, and institutional grounds and buildings. 
   2. Description of the Prior Art 
   Development of appliances such as grass trimmers having rapidly rotating filament blades, popularly known as string trimmers, have come into widespread use. The principal application of string trimmers is to cut small areas of tall grass and weeds to the level of surrounding grass. In particular, string trimmers are used at the borders of large expanses of grass wherein the border becomes irregular in configuration due to the presence of trees, lighting poles, fences, buildings, and other tall structures. String trimmers are also used to extend the reach of lawn mowers, such as along fences and buildings at ground level, and under overhanging foliage. 
   While string trimmers are convenient, practical, and generally suited to the aforementioned tasks, the burden they impose on a user becomes increasingly onerous over time. Unless the user is unusually strong, he or she will become fatigued and become unable to continue or will notice that control over the device is becoming tenuous as the trimmer is used. The prior art has taken note of this problem, and has proposed wheeled supports as a solution. 
   However, even wheeled string trimmers and like appliances are limited in their use in that the wheels dictate where the working element such as a rotating filament or a rigid blade may be brought to bear. This is because the appliance can be pivoted about the axle, but cannot be adjusted or maneuvered readily in other ways (i.e., adjustment of prior art devices is limited to one degree of freedom). Usefulness of wheeled appliances would be greatly increased if additional adjustment and maneuverability were available. The prior art is not seen to describe the instant invention as claimed. 
   SUMMARY OF THE INVENTION 
   The present invention sets forth a two wheeled carriage for supporting an appliance such as a string trimmer by the shaft of the trimmer. A significant improvement over the prior art is that maneuvering and adjustment are provided for in ways other than by pivoting the appliance about the rotational axis of the axle. One such adjustment is that the appliance may be oriented on the wheeled carriage such that the working element may be rotated to project to either the right or left side of the appliance. This enables the appliance to be wheeled along its path with cutting taking place selectively to the right or the left beyond the wheels. In prior art devices, cutting takes place in front of and between the wheels. The novel improvement is used, for example, to trim below the lowermost rail of a rail fence and in other places wherein the wheels are obstructed. This angular adjustment can be further modified by inclining the appliance about the axle, thereby cutting at levels higher than that of the environmental surface on which the wheels rest. For example, a flower bed abutting an adjacent walkway may have a grade level above that of the walkway. This bed may be trimmed while propelling the appliance along the walkway. 
   Other adjustments vary deviation of the shaft of the appliance from the horizontal direction. These adjustments enable the handle to be located for ergonometric convenience. The prior art practice of inclining a trimmer and wheel assembly by raising and lowering the handle to vary height of the working element above the ground may cause weight distribution and handle position to become awkward, uncomfortable, and inefficient. The deviational adjustments address these shortcomings. Deviational adjustments in the present invention may also be made so that the rotating filament or other working element impinges upon the ground vertically. When adjusted to this degree, the appliance may take on additional capabilities, such as a string trimmer being utilized as an edger, while still balancing the appliance over the axle of the auxiliary carriage. 
   The carriage grasps the shaft of the trimmer in one embodiment by an encircling clamp tightened by an over-center arrangement. This feature provides positive grasp of the shaft, while eliminating fasteners which could become lost and which may require tools to tighten. It also can be fastened and unfastened in seconds, which makes it highly practical to convert between the wheeled and unwheeled configurations. 
   Accordingly, it is one object of the invention to overcome shortcomings and to expand upon abilities of the prior art. 
   It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
       FIG. 1  is a diagrammatic environmental, side elevational view of an embodiment of the invention. 
       FIG. 2  is a front elevational view of the embodiment of FIG.  1 . 
       FIG. 3  is an enlarged perspective detail view of the upper part of FIG.  2 . 
       FIG. 4  is a diagrammatic, top plan view of the embodiment of FIG.  1 . 
       FIG. 5  is an enlarged side elevational detail view of an optional adjustment feature not shown in the previous Figures. 
       FIG. 6  is a side elevational detail view of an alternative embodiment of the invention depicting a modification to the upper right of FIG.  3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  of the drawings shows wheeled carriage  10  engaging and supporting an appliance such as string trimmer  2  having an elongate shaft  4 . String trimmer  2  is shown in an operative position relative to both carriage  10  and the ground G. In this position, working head  6  of string trimmer  2  is located just above ground G, thereby enabling a rotatable filament or other blade (neither shown) to cut grass and other vegetation just above ground level. Handle  8  of string trimmer  2  is located roughly at the waist level of an adult (not shown). This is a convenient and ergonomically suitable location and orientation of handle  8 . String trimmer  2  will be understood to be representative of any conventional type of trimmer having a rotatable filament or other blade, encompassing both electrically operated and also those having onboard internal combustion engines. Although trimmers may vary in configuration, weight distribution, center of gravity, and in other ways, a great variety of trimmers and other appliances are accommodated by the present invention, as will become apparent. 
   Referring also to  FIG. 2 , carriage  10  has two wheels  12 ,  14  which rest on ground G in the operative position. Wheels  12 ,  14  are each mounted on an axle  16  enabling rotation about a rotational axis  18 . In an embodiment especially suited for care of ordinary lawns and turf, wheels  12 ,  14  have a minimum diameter D of at least nine inches. This dimension assures that wheels  12 ,  14  will resist binding and changing of steering direction when negotiating minor variations in turf surfaces which are normally encountered in lawns. 
   A clamp, which will be described hereinafter, is mounted to axle  16  in a manner such that it remains in a constant position when wheels  12 ,  14  rotate about rotational axis  18 . This may be accomplished by fixing wheels  12 ,  14  to axle  16  and supporting axle  16  at a bearing  20 . Alternatively, wheels  12 ,  14  may be arranged to rotate on axle  16 . Regardless of the rotational arrangement of wheels  12 ,  14 , the clamp is disposed to receive and retain elongate shaft  4  of the appliance releasably to wheeled carriage  10 . 
   A rigid plate  22  projects upwardly relative to the operative position from bearing  20 . A swivel joint  24  mounted to plate  22  is disposed to adjust angular orientation of the clamp relative to rotational axis  18  of axle  16 . This is accomplished by mounting the clamp above swivel joint  24 . Swivel joint  24  may take any suitable form. 
   The clamp comprises any suitable grasping element arranged to secure elongate shaft  4  of string trimmer  2 . In the preferred embodiment, the grasping element comprises a flexible strap  26  capable of conforming to shafts of different configurations and dimensions, and an adjustable connector  28  disposed to connect to strap  26  and to tighten strap  26  over shaft  4  as shown in FIG.  1 . In the embodiment of  FIG. 1 , the grasping element encircles shaft  4 . While encirclement is not absolutely necessary, it is desirable as providing secure engagement of shaft  4 . As seen in  FIG. 1 , two generally identical grasping elements are provided. 
   The grasping elements are supported on a plate  30  which projects upwardly from swivel joint  24 . Plate  30  has fixed thereto a first saddle  32  and a second saddle  34  disposed in fixed relation to rotational axis  18  of axle  16 . Saddles  32 ,  34  are disposed to receive shaft  4  and hold shaft  4  at a fixed distance in relation to rotational axis  18  when shaft  4  is urged firmly against saddles  32 ,  34  by tightening of strap  26  of one grasping element and strap  36  of the second grasping element. In the embodiment of  FIG. 1 , saddles  32 ,  34  are spaced apart from one another. This better resists moments which may be applied when a human operator maneuvers the mounted string trimmer by handle  8 . Of course, more than two saddles may be provided. Also, one long, continuous saddle may be provided to assure secure mounting of shaft  4  to carriage  10 . Regardless of the number of saddles, a saddle or saddles are oriented such that shaft  4  of the trimmer is secured by the clamp in perpendicular and non-intersecting relationship to axle  16 . 
   Turning now to  FIG. 3 , the clamp is more particularly described. Each grasping element is supported at plate  30  by two rigid webs. The grasping element at the right of  FIG. 3  includes webs  38 ,  40  and  42 ,  44 . A pin  46  is fixed at its two ends to webs  38 ,  40 . Strap  26  is anchored at pin  46  at its proximal end. Similarly, a pin  48  is fixed at its two ends to webs  42 ,  44 . A lever  50  is pivotally mounted on pin  48 . A threaded fastener such as screw  52  serves as a connector which is threadably and adjustably fixed to carriage  10 . Strap  26  and lever  50  are complementary closing members which mutually interengage to entrap shaft  4  and secure strap  4  to carriage  10 . Saddles  32 ,  34 , which are seen in  FIG. 3  each to comprise a vee-shaped trough, provide a secure seat for receiving shaft  4 . Shaft  4  is secured to carriage  10  when clamped against saddles  32 ,  34 . It would be possible to eliminate saddles  32 ,  34  and to cause the clamp elements to retain shaft  4  directly thereto if desired. 
   Strap  26  bears at its free distal end an eye  54  which is dimensioned and configured to engage and retain the threaded shaft of screw  52  when the shaft is passed through eye  54 . Threading screw  52  into lever  50  reduces the operable circumference which can be encircled by lever  50  and strap  26 . This provides adjustment for accommodating shafts of different dimensions. The flexible nature of strap  26  accommodates shafts of different outer configurations, where such shafts may depart from circular or tubular configurations. 
   Lever  50  is arranged in an over-center arrangement such that pressing the free end of lever downwardly, as depicted in  FIG. 3 , will cause the head of screw  52  to urge eye  54  into increasingly tight engagement with lever  50 , thereby securing the clamp in a closed position. The over-center arrangement assists in opposing spontaneous release of shaft  4 . 
   The second grasping element located at the left of  FIG. 3  is essentially identical to that at the right of FIG.  3 . The second grasping element includes flexible strap  36  bearing an eye  56 , and a lever  58  having a screw  60 . Whereas the first grasping element is depicted with strap  26  disconnected from lever  50 , the second grasping element is depicted with its corresponding strap  36  disposed in engagement with screw  60  of corresponding lever  58 . Locations of saddles  32 ,  34  may be interchanged with those of the first and second grasping elements of the clamp if desired. An advantage of providing two saddles  32 ,  34  and two corresponding straps  26 ,  36  is to accommodate some appliances (not shown) which are so arranged that structure such as motor housings must be mounted to a saddle  32  or  34  for the appliance to be balanced on carriage  10 , or to be positioned for effective reach and location of its working head. Many electric string trimmers are configured such that their housings must be mounted to upper saddle  34  (as depicted in FIG.  1 ). Provision of two straps  26 ,  36  spaced apart from one another along the length of a shaft of an appliance such as an electric string trimmer enables the shaft and housing of the electric string trimmer each to be encircled and firmly secured to carriage  10  despite different circumferences and configurations. 
     FIG. 4  shows how angular orientation of the clamp may be varied with respect to the rotational axis of axle  16 . As shown in  FIG. 4 , the azimuth of the longitudinal axis of shaft  4  (see  FIG. 1 ) can be adjusted throughout an angle  62 . Magnitude of angle  62  may be limited by stops (not shown), or alternatively may extend to three hundred sixty degrees if interference of shaft  4  with other objects such as wheels  12 ,  14  is avoided. Variable angular orientation of the clamp provides ability to cut to one side of carriage  10  while propelling carriage  10  alongside of and parallel to the swath of the cut. In  FIG. 4 , the swath of the cut is that area between broken lines  64  and  66 . Forward motion of carriage  10  is indicated by arrow  68 . 
   Returning to  FIG. 3 , carriage  10  is seen to include a latch disposed to lock plate of swivel joint  24 , and-therefore saddles  32 ,  34  and the clamp selectively and releasably in any one of a plurality of positions of angular orientation of the clamp to rotational axis  18  of axle  16 . The latch comprises a swing arm  70  pivotally mounted to plate  30  on a pin  72 . Arm  70  includes a downwardly projecting finger  74  which can enter any one of a plurality of notches  76 ,  78 ,  80  formed in an upper wall  82  of swivel joint  24 . Number, spacing, and magnitude of the angle of the array of notches may be varied to suit. Finger  74  may be retained in a notch by gravity or optionally by spring bias or mechanical entrapment. 
   In the embodiment of  FIG. 3 , plate  30  is fixed to a plate  84  which is rotatably entrapped within swivel joint  24 . Therefore, when plate  22  and wall  82  remain in one position, plate  30 , saddles  32 ,  34 , and the clamp are free to rotate about a vertical axis, as depicted in FIG.  3 . Azimuth of shaft  4  (see  FIG. 1 ) rotates accordingly, as seen in FIG.  4 . Arm  70  preferably includes a handle  86  for conveniently grasping and lifting arm  70  when finger  74  engages any notch  76 ,  78 , or  80 . 
   Turning now to  FIG. 5 , carriage  10  optionally includes an elevational angle adjuster disposed to vary angular orientation of the clamp and of shaft  4  with respect to a horizontal direction selectively when the clamp is prevented from pivoting ineffectually about axis  18 , when axle  16  remains horizontally oriented. An adjustable joint as shown in  FIG. 5  may be interposed at any suitable point between axle  16  and the clamp to effect this adjustment. 
   The adjustable joint comprises a first member such as plate  88  bearing adjustment holes  90 ,  92 ,  94 ,  96 ,  98 ,  100 ,  102 ,  104 , and a second member such as plate  106  bearing a plurality of alignable adjustment holes which in the depiction of  FIG. 5  are aligned with and thus exactly overlie holes  90 , 92 ,  94 ,  96 ,  98 ,  100 ,  102 ,  104  and therefore are not visible in  FIG. 5. A  fastener such as bolt  108  passes through an elongated adjustment slot  110  and a corresponding adjustment hole (not visible) formed in plate  106 . A second fastener such as bolt  112  passes through adjustment hole  100  of plate  88  and an aligned corresponding hole (not visible) formed in plate  106 . Bolts  108  and  112  will be understood to include threadably mating nuts (not separately shown). Plate  106  is therefore adjustably secured to plate  88 . Although only two fasteners  108 ,  112  are shown, it would be possible to utilize additional fasteners (not shown) for greater security if desired. 
   It is possible to vary angular position of plate  106  with respect to plate  88  by rotating plate  106  about the center of bolt  108 , until an adjustment hole formed in plate  106  which is different from that aligned with hole  100  aligns with an adjustment hole  90 ,  92 ,  94 ,  96 ,  98 ,  100 ,  102 , or  104  of plate  88 . This angular variation is indicated by projection lines  114 ,  116 . It must be recognized that lines  114 ,  116  are illustrative only and do not limit or define the extent of angular adjustment of plate  106 . It is preferred that angular adjustment of plate  106  be sufficient to enable string trimmer  2  to be utilized as an edger, with its rotatable filament positioned to form a generally vertical trench in the ground. 
   It will also be seen that the nature of slot  110 , taken together with location and spacing of adjustment holes formed in plate  106 , enable the adjustment joint to act as a height adjuster disposed to vary height of the clamp selectively with respect to axle  16 . This is accomplished by slackening the nut of bolt  108 , moving plate  106  vertically upwardly or downwardly, as depicted in  FIG. 5 , and reinstalling and tightening the nut of bolt  108  and the nut of bolt  112 , with bolt  112  being relocated appropriately in different adjustment holes. 
   The adjustable joint of  FIG. 5  may be located between axle  16  and swivel joint  24 , formed as part of swivel joint  24 , or may be located between swivel joint  24  and the clamp. Least complicated construction will result when either of plate  22  and plate  30  is modified to include the adjustable joint of FIG.  5 . If plate  22  is so modified, then one member of the adjustable joint is secured to axle  16 . If plate  30  is so modified, then one member is secured to the clamp. 
   It will be appreciated that separate adjustment holes  90 ,  92 ,  94 ,  96 ,  98 ,  100 ,  102 ,  104  may be eliminated in favor of a single elongate arcuate slot (not shown) corresponding in nature to slot  110  if desired. It would also be possible to modify the joint of  FIG. 5  to provide only vertical adjustment or only angular adjustment if desired. 
   Swivel joint  24 , the elevational angle adjuster, and the height adjuster, taken individually or in any combination, serve as an orientation adjuster which enables selective adjustment of location and orientation of the working head of the appliance with respect to the ground, with axle  16  being maintained in a constant orientation with respect to the ground. 
     FIG. 6  shows an alternative embodiment of the invention wherein an optional feature allows for coarse adjustment of the effective length of straps corresponding to straps  26  and  36  of  FIG. 3. A  keeper  118  releasably clamps the free end of strap  120  to plate  122 , which plate  122  corresponds functionally to plate  30  of FIG.  3 . Keeper  118  may be released from the clamping position by slackening screws  124 ,  126 . Effective length of strap  120  is adjusted according to the circumference it must envelop, this referring to the shaft or housing of the appliance being fastened. Keeper  118  is then tightened to plate  122  using screws  124 ,  126 , with strap  120  now clamped in a new adjusted position. This embodiment is an alternative to fixed anchorage of straps  26 ,  36  shown in FIG.  3 . 
   A second keeper and a second strap (not show) formed essentially as a mirror image of keeper  118  and strap  120  are preferably provided, and are located in a manner similar to that of straps  26  and  36  of FIG.  3 . Adjustment corresponding to adjustment of screw  60  and engagement of the straps of the embodiment of  FIG. 6  of an appliance may be essentially similar to those of FIG.  5 . Keeper  118  may be hinged (this is not shown) or otherwise operably attached to plate  122  if desired. Screws  124 ,  126  may be replaced by a latch (not shown) or other apparatus to facilitate operation and to eliminate threat of loss of small parts if desired. 
   The present invention is susceptible to further variations and modifications which may be introduced without departing from the inventive concept. Carriage  10  may, for example, include suitable braces and gussets (not shown), disposed to oppose bending of plates  22 ,  30  and other members, or to reinforce any member. Saddles  32 ,  34  may be configured other than as vee-shaped. For example, saddles (not shown) may be semi-circular or have flat bottoms. 
   Appliances utilized with the novel carriage may be other than a string trimmer. For example, the appliance may be a torch, vacuum device, hand held blower, fluid spraying or dispensing device such as a paint gun or a device for dispensing solvents, lubricants, adhesives, pesticides, herbicides, protective chemicals such as fire retardants and water resistant substances, or still others. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.