Patent Publication Number: US-6340061-B2

Title: Lawn and garden tool

Description:
This application is a continuation, division, of application Ser. No. 09/352,289 filed Jul. 13, 1999, which is incorporated by reference herein in its entirety, now U.S. Pat. No. 6,189,627. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a lawn and garden tool and, more particularly to a portable tool having interchangeable implements which operate at high torque and low speed. 
     BACKGROUND OF THE INVENTION 
     Preparation and maintenance of lawns and gardens has great commercial and homeowner interest. Portable tools for work on lawns and gardens are largely manually operated. In recent years, the use of powered tools has increased especially gasoline engine and electrically powered tools. These tools include lawn edgers, trimmers, cultivators, leaf blowers and hedge trimmers. 
     In U.S. Pat. No. 4,213,504 Schneider discloses a rotary, hand-held apparatus for performing various soil working operations. The soil working implements selectively include soil engaging tines, auger, drill, etc. The device may employ manual, electrical, gas, etc. power sources and cultivating, mulching, weeding, boring, etc. implements. In one embodiment, an electric drill is secured to a handle to drive the implements. In U.S. Pat. No. 4,293,041 Holmstadt et al disclose a power cultivator with a debris-excluding barrier and scraper, wherein the tillers are counter-rotated and include interdigitating tines which engage and move the earth forwardly. Worm gears on the tillers are driven by a common centrally located shaft mounted worm gears. Rickard et al in U.S. Pat. No. 5,802,724 and Everts et al in U.S. Pat. No. 5,809,653 disclose a coupling for a split-boom power tool having an attachment which may include a hedge trimmer, line trimmer, pruner, blower or extension. The motor directly drives the attachment, there being no gearing therebetween. Lessig III et al in U.S. Pat. No. D 252,879, disclose an electric-powered earth tiller. 
     In U.S. Pat. No. 2,975,848 Roberts discloses a portable power-driven device for boring holes which has a pinion gear on the power shaft of the motor and a larger driven gear meshing with the teeth of the pinion gear. The driven gear is attached to the shaft of a chuck. In U.S. Pat. No. 4,366,871 Dieterle et al disclose a motor-driven screwdriver, wherein a planetary gear carrier carries a plurality of circumferentially-displaced planet gears meshing with a pinion driven by the motor of the screwdriver. The screwdriver does not have a cascade of planet gears. 
     There is a need for a portable power-driven lawn and garden tool which has interchangeable implements. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a portable, power-driven lawn and garden tool which has interchangeable implements and the implements are driven at high torque and low speed. 
     In accordance with the teachings of the present invention, there is disclosed a hand-held portable power driven tool for using a tool implement. A housing encloses a permanent magnet electric motor. The motor drives a planetary gear system having at least two sets of gears arranged in cascade to provide a low speed, high torque output. The output of the gear system drives the tool implement. The motor is powered by at least one rechargeable battery pack, the battery pack being replaceably inserted into the lawn and garden tool. 
     In further accordance with the teachings of the present invention, there is disclosed a portable, hand-held lawn and garden tool which has a wand having a first end and an opposite second end. A handle is connected to the first end and a housing is connected to the second end. A first set of gears is disposed in the housing, the first set of gears being a sun gear engaging a plurality of planetary gears. A plurality of sets of gears similar to the first set of gears are provided, the sets of gears being connected in cascade to an output shaft. A plurality of implements are provided. A selected one of the implements is removably attached to the output shaft connected to the cascade of sets of gears, wherein the respective implements are interchangeable. Means are provided for driving the sets of gears connected to the sets of gears such that the selected implement is driven at a selected high torque and a selected low speed dependent upon the arrangement of the plurality of sets of gears. 
     Also in accordance with the teachings of the present invention, there is disclosed a portable lawn and garden tool. The tool has a wand having a first end and an opposite second end. A handle is connected to the first end. A motor in a housing is attached to the second end. A source of power is provided for the motor and a switch is disposed in the handle to control the power to the motor. A first set of gears is attached to the motor within the housing. The first set of gears is a sun gear engaging a plurality of planetary gears. A plurality of sets of gears similar to the first set of gears is provided, the sets of gears being connected in cascade. A plurality of implements are provided, a respective one of the plurality is removably attached to the cascade of sets of gears. The respective implements are interchangeable. The implement is driven at a selected high torque and a selected low speed depending upon the arrangement of the plurality of sets of gears. 
     Still further in accordance with the teachings of the present invention, there is disclosed, in a lawn-and-garden tool, the combination of a housing having a longitudinal axis and further having respective side portions. Each of the respective side portions has an opening formed therein generally parallel to the longitudinal axis of the housing. At least one slide-in rechargeable battery pack is removably received in each of the openings in the housing, such that the housing is balanced. A permanent magnet motor is disposed within the housing and selectively energized by the battery packs. A plurality of planetary gear systems are driven by the motor and arranged in cascade in the housing. An output shaft is powered by the planetary gear systems, the output shaft having a relatively-low output speed and, conversely, a relatively-high output torque. A tool implement is disposed externally of the housing and driven by the output shaft. 
     In another aspect of the present invention, there is disclosed a tool having a drive means having a motor. A gear system having a plurality of planetary gear is driven by the motor. A single ring gear engages the plurality of planetary gears. 
     These and other objects of the present invention will become apparent from a reading of the following specification taken in conjunction with the enclosed drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the tool of the present invention with one of the interchangeable implements adjacent to the tool and another of the implements attached to the tool. 
     FIG. 2 is a bottom view of the tool with the adapter plate and output shaft removed. 
     FIG. 3 is a partial cut-away view of the housing showing the motor and the sets of gears, the gears and a portion of the housing being in cross section. 
     FIG. 4 is a side elevation of the motor and gear. 
     FIG. 5 is a bottom plan view of the motor showing the input gear. 
     FIG. 6 is a bottom plan view of the internally toothed annulus. 
     FIG. 7 is a top plan view of the sun gear. 
     FIG. 8 is a side elevation view of the sun gear of FIG.  7 . 
     FIG. 9 is a top plan view of a planetary gear. 
     FIG. 10 is a side elevation view of the planetary gear. 
     FIG. 11 is a side elevation view of the output shaft. 
     FIG. 12 is a side elevation view of the output housing. 
     FIG. 13 is a top plan view of the output housing. 
     FIG. 14 is a bottom plan view of the adapter plate. 
     FIG. 15 is a side elevation view of the adapter plate. 
     FIG. 16 is a bottom elevation view of the tiller implement. 
     FIGS. 17-19 are a sequence of perspective views showing the attachment of the implement by a twist and lock system. 
     FIG. 17 is a perspective view of the tiller implement being moved toward the tool. 
     FIG. 18 is a perspective view showing the pins on the tool being inserted into the slots in the implement. 
     FIG. 19 is a perspective view showing the twisting of the implement with respect to the tool to lock the pins in the slots. 
     FIG. 20 is a partial cut-away view showing the implement connected to the output of the tool. 
     FIG. 21 is a view across lines  21 — 21  of FIG. 20 showing the battery wells in the housing. 
     FIG. 22 is a perspective view showing the rechargeable batteries being inserted into the tool. 
     FIG. 23 is a perspective view of the handle portion of the tool having a replaceable battery pack. 
     FIG. 24 is an electrical diagram showing the connection of the power source to the motor through a switch. 
     FIG. 25 is a perspective view showing the length of the wand being adjusted. 
     FIG. 26 is a side elevation view of an alternate embodiment showing an angled handle having a connector therein to which is attached an electrical cord to a source of power. 
     FIG. 27 is an alternate embodiment having a D handle attached to the housing. 
     FIG. 28 is a perspective view of the tool having an internal combustion engine. 
     FIG. 29 is a side elevation view of an auger-type implement. 
     FIG. 30 is a side elevation view of a side-by-side tiller implement. 
     FIG. 31 is a top plan view of the side-by-side tiller implement. 
     FIG. 32 is a side elevation view of one embodiment of an arm of the tiller implement. 
     FIG. 33 is an enlarged cross section view taken along the lines  33 — 33  of FIG.  32 . 
     FIG. 34 is a side elevation view of another embodiment of an arm of the tiller having a cutting blade. 
     FIG. 35 is an enlarged cross section view taken across the lines  35 — 35  of FIG.  34 . 
     FIG. 36 is an end view of a core drill mounted on the implement plate. 
     FIG. 37 is a side elevation view of the core drill mounted on the implement plate. 
     FIG. 38 is a perspective view of a mixer mounted on the implement plate. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The power-driven lawn and garden tool  10  has a wand  12  with a handle  14  at one end and a housing  16  at the opposite end (FIG.  1 ). The housing  16  contains an electric motor  18 . The electric motor  18  may be a permanent magnet-type low voltage motor powered by batteries as will be described or it may be a motor powered by standard AC current and connected by wire to a standard convenience outlet. A battery-powered motor which has been found satisfactory is Model HC683LG manufactured by Johnson which has a nominal speed of approximately 7000 rpm and an output torque of approximately 20 inch ounces. Other types of electric motors known to persons skilled in the art may be used. An electric switch  20  is mounted in the tool  10  to control power to the electric motor  18 . Preferably, the switch  20  is located in the handle  14  convenient to the hand of the operator of the tool. 
     On the inner wall of the housing  16 , there is formed an annular internal gear  24  (a ring gear) having spaced-apart teeth (FIGS.  2  and  6 ). Also within the housing  16 , there is disposed a plurality of sets of gears  22  which are connected to the motor  18  (FIGS.  2 - 5 ). Each set of gears  22  has a centralized sun gear  26  (FIGS. 7-8) which has teeth to engage cooperating teeth on a plurality of planetary gears  28  (FIGS.  9 - 10 ). The gears are connected with pins  27 . The output of the motor  18  preferably is an output gear  30  (FIGS. 2,  4 ,  5 ) which drives the first planetary gear  28  in the first set of gears  22 . The sets of gears  22  are connected in a cascade or stacked manner in such a manner as to significantly reduce the speed of the sets of gears from the speed of the motor. The gear ratio, preferably is approximately 120:1 to 160:1 so that the output of the sets of gears is less than 100 rpm at very high torque. At a ratio of 120:1, the output torque is in the range of 6-12 foot pounds. In a preferred embodiment, the output torque is 8.88 foot pounds. The output speed is approximately 30-60 rpm with a preferred speed being approximately 40 rpm. The output speed and torque is dependent on the speed of the motor and the arrangement and types of gears used in the sets of gears  22  and may be selected during manufacture of the tool to provide the desired speed and torque consistent with the nature and types of implements which will be used with the tool  10 . An advantage of the gear arrangement and the low speed output is to reduce drain on the batteries and provide a longer battery life in the embodiment which is powered by batteries. The output of the set of gears  22  is connected to a selected implement  32  by means known to persons skilled in the art. In a preferred embodiment (FIG. 2) the output of the sun gear  26  of the final set of gears  22  is formed as an elongated bar  34  which is received in and engages a cooperating slot  34 ′ in an output shaft  31 . It is further preferred that the output shaft  31  pass through an output housing  33  which spaces the selected implement from the gear set  22  (FIGS.  11 - 13 ). The output shaft  31  has an end distal from the gear set  22  which may be threaded to be received in a cooperatively threaded nut-like means  35  connected to the adapter plate  40 . It is understood that other means, such as engaging gears, may be used to transmit force between the gear sets  22  and the implements  32 . 
     A plurality of implements  32  are provided for use as a part of the tool. The implements  32  are all interchangeably attached to the housing  16  by a simple easily connected/disconnected means (FIGS.  14 - 16 ). A preferred means is a twist and lock type junction in which projecting pins  38  on the adapter plate  40  attached to the output of the sets of gears  22  is engaged in slots or recesses  44  in the implement plate  42  (FIGS.  17 - 19 ). The drive from the gear sets is directly engaged with the rotatable center shaft in the implement as noted above. Other locking means may be used. 
     The implements may be many and of varied types. The following are typical examples and are not, in any manner, limiting. FIGS. 16-20 show a tiller (aerator)  36  having three angled arms  37  with pointed tips. The tiller arms  37  may be straight or angled. The tiller arms may have a flat or sharpened leading edge to be selected depending upon the nature of the soil, i.e., sandy or loose (FIGS. 32 and 33) or clay soil, roots, etc. (FIGS.  34  and  35 ). Also, the tiller may have two arms or four arms. Additional implements may be an auger  32  which may be used for digging post holes, aerating and fertilizing (FIGS.  1  and  28 ), a core drilling implement  60  for bulb planting (FIGS.  36  and  37 ), a mixer for concrete, driveway coating, etc. (FIG. 38) and other implements not limited to those set forth herein. The tool  10  may also drive two cooperating implements such as side-by-side tillers  46  (FIGS.  30  and  31 ). One tiller is driven in a clockwise direction and the second tiller is driven in a counterclockwise direction. This type of tiller does not “walk” during use and provides more effective working of the ground. Thus, the lawn and garden tool of the present invention is a very versatile tool. 
     As shown in FIGS. 17-19, the implement  32  is easily attached and removed from the tool  10 . A center opening in the implement plate  42  is aligned with the nut-like means  35  on the adapter plate  40  such that the pins  38  on the adapter plate  40  are oriented with respect to the recesses  44  in the implement plate  42 . Alternately, the pins  38  may be on the implement plate  42  and the recesses  44  may be in the drive plate. Also, the drive means on the output of the sets of gears (such as the bar  34 ) is simultaneously aligned with the slot in the center shaft of the implement. Preferably, the pins  38  have an enlarged head and the recesses are in the form of a slot having an end with an enlarged diameter. The heads of the pins  38  are received in the enlarged diameter of the recesses and the adapter plate  40  and the implement plate  42  are twisted with respect to one another such that the heads of the pins  38  are locked in the more narrow portion of the recesses thereby securing the implement plate  42  (and also the implement) with the adapter plate  40  (and also the tool  10 ). Reversing the procedure removes the implement  38  from the tool  10 . 
     Also, the tool may be made as a single purpose tool with the implement  32  permanently attached to the output of the gear system. Thus, a family of tools may be provided, each for a specific use. 
     The battery-operated embodiment preferably has at least one replaceable, rechargeable battery  48  removably received in the tool  10  (FIGS. 21,  22  and  23 ). Preferably, a battery pack is used and in one embodiment, four battery packs such as “VERSAPAK” Model VP 100 Type 2 made by Black and Decker are slidably received in pockets or wells  49  formed in the outer surface of the housing  16 . In this embodiment the battery pack may have a positive center post and a negative annular ring which makes electrical contact with cooperating positive and negative terminals  49 ,  50  in the pocket  50 . This arrangement assures electrical contact and prevents incorrect insertion of the battery pack. A means such as a clamp, detent means or retaining pocket cover is provided to keep the battery pack in the pocket and in electrical contact during use of the tool  10 . It is understood by persons skilled in the art that other types of batteries may be used and may be mounted in the tool in a manner different from the example described above. For example, a rechargeable battery may be mounted in the tool with an electrical connection for recharging the battery. 
     For example, FIG. 23 shows a battery pack  48  such as “SKIL 92931” made by S. B. Power Tool which is attached to the handle  14 . The battery pack  48  may have prongs which make electrical contact with cooperating receptors in the handle  14 . An electrical switch  20  may be incorporated in the handle  14 . The switch  20  may be load sensitive to open and remove power from the tool if the current spikes due to the tool locking up or jamming. 
     FIG. 24 shows a typical electrical wiring diagram. If the battery is formed from more than one battery pack, the batteries are connected in series. In a four battery pack, each battery pack has an output voltage of 3.5V to power the 14V motor. It is understood that the voltage of the motor may be different from the example given herein and battery packs having the appropriate voltage would be used. An electrical switch  20  is to provide the operator with control over the power to the tool. A typical layout of the disposition of the battery connections in the tool  10  is shown in FIG.  21 . 
     The tool  10  may be used by a standing, kneeling or seated operator and, to have a versatile tool which can be used in all of these postures and also to provide.more comfortable use by operators of differing heights, the wand  12  may be made adjustable (FIG.  25 ). A telescoping wand may be provided with adjustable stop and locking means known to persons skilled in the art. Alternately, the wand  12  may be made with a shorter length and a separate embodiment may have a longer length. 
     The tool  10  may be powered by standard commercially available electrical power such as 115V AC. FIG. 26 shows an angled handle  14  on the first end of the wand  12  with an electrical connector formed in the angled handle  14 . An electrical cord is connected to the connector in the handle  14  and extends to a convenience outlet for 115V AC power. The electrical cord may also be connected to a source of power carried as a back pack or waist pack by the operator. The switch  20  is placed in the handle  14  for ready access to the hand of the operator. Also, an auxiliary balance handle  54  may be mounted on the wand  12  to assist the operator in two-handed use of the tool  10 . The balance handle  54  may be fixedly or adjustably mounted on the wand and may include an extension to assist in torque control. 
     In still another embodiment (FIG.  27 ), a D-shaped handle  56  may be formed on the first end of the wand  12  or may be formed on the housing  16 . An auxiliary handle  54  may be included to steady the tool against rotation while in use. Other handle shapes such as a pistol type handle may be used. 
     The tool  10  may also be powered by an internal combustion engine  58  (FIG.  28 ). The output from the engine  58  is used to drive the sets of gears  22  in a manner similar to the drive by electrical motors. A switch is included in the handle to turn off the engine  55 . 
     Thus, there is disclosed a compact, portable tool which has interchangeable implements and is used for lawns and gardens. Due to low speed, high torque output obtained from the engine gearing between the power source and the implements, a very efficient tool is provided. 
     Obviously, many modifications may be made without departing from the basic spirit of the present invention. Accordingly, it will be appreciated by those skilled in the art that within the scope of the appended claims, the invention may be practiced other than has been specifically described herein.