Patent Publication Number: US-2010122516-A1

Title: Adapter for landscape trimmers

Description:
BACKGROUND 
     The present invention relates to an adapter for a landscape trimmer, and more particularly, an adapter that attaches a string head to different gear heads. 
     Generally, landscape trimmers are used to cut grass and weeds, and are often used to edge around trees, near fences and walls, and along landscape borders. Conventional landscape trimmers have an elongated shaft with a rotating element or gear head near the end of the elongated shaft, and a spool or string head is attached to the gear head. Typically, the string head includes a monofilament line or other cutting devices that are rotated by the gear head for cutting and trimming along landscaped areas, fences, and walls. 
     Some gear heads have an attachment member that is sized or fitted for a particular string head with an attachment portion that corresponds to the attachment member such that other string heads without corresponding attachment portions cannot be attached to the gear head. 
     SUMMARY 
     In one construction, the invention provides an adapter for a landscape trimmer that includes a string head and an output shaft. The adapter includes an adapter body that has a first end and a second end. The adapter also includes a string head portion, and a trimmer attachment portion. The string head portion is positioned proximate the second end and extends axially toward the first end, and is adapted to couple the string head to the adapter body. The trimmer attachment portion is positioned proximate the first end, and defines a hollow shaft that extends axially toward the second end along the adapter body and that is adapted to receive the output shaft therethrough. The trimmer attachment portion further defines a slot that extends at least partially through the adapter body substantially transverse to and in communication with the hollow shaft. 
     In another construction, the invention provides an adapter for a landscape trimmer that includes a string head and an output shaft that has an external diameter. The adapter includes an adapter body having a first end and a second end. The adapter also includes a string head portion, an intermediate portion, and a trimmer attachment portion. The string head portion is positioned proximate the second end and extends axially toward the first end, and is adapted to couple the string head to the adapter body. The intermediate portion is positioned proximate the string head portion between the first end and the second end, and is configured for engaging with the string head. The trimmer attachment portion is positioned proximate the first end, and defines a hollow shaft that extends toward the second end along the adapter body and that is adapted to receive the output shaft therethrough. The trimmer attachment portion further defines a slot that extends at least partially through the adapter body substantially transverse to and in communication with the unthreaded opening. The slot is adapted to receive a plurality of fasteners therethrough, the plurality of fasteners including a first fastener having a first internal diameter and a second fastener having a second internal diameter that is different from the first internal diameter to removably couple different output shafts to the adapter. 
     In yet another construction, the invention provides a landscape trimmer that includes a gear head that has a rotatable output shaft having an external diameter. The landscape trimmer also includes a string head and an adapter that is coupled between the gear head and the string head such that rotation of the output shaft is transferred to the string head. The adapter includes a string head portion that is configured for coupling to the string head, a trimmer attachment portion that is positioned opposite the string head portion and that defines a hollow shaft extending axially toward the string head portion and adapted to receive the output shaft therethrough, and an intermediate portion disposed between the string head portion and the trimmer attachment portion. The trimmer attachment portion further defines a slot that extends at least partially through the adapter body substantially transverse to and in communication with the hollow shaft. The intermediate portion is engaged with the string head such that rotation of the adapter is transmitted to the string head. The landscape trimmer further includes a fastener that has an internal diameter corresponding to the external diameter of the output shaft, and that is insertable into the slot to couple the output shaft to the adapter. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a portion of a landscape trimmer according to one construction of the invention and including a first gear head having a first output shaft, an adapter, a string head, and a retainer. 
         FIG. 2  is an exploded perspective view of a portion of another construction of a landscape trimmer including a second gear head having a second output shaft, the adapter, the string head, and the retainer. 
         FIG. 3  is an exploded perspective view of the adapter of  FIGS. 1 and 2  and an adapter nut portion. 
         FIG. 4  is a side view of the adapter of  FIG. 3 . 
         FIG. 5  is another side view of the adapter of  FIG. 3 . 
         FIG. 6  is a section view of the adapter of  FIG. 5  taken along line  6 - 6 . 
         FIG. 7  is a top view of the adapter of  FIG. 3 . 
         FIG. 8  is a bottom view of the adapter of  FIG. 3 . 
         FIG. 9  is a section view of an adapter for the landscape trimmer of  FIG. 1  according to another construction of the invention. 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a portion of a landscape trimmer  10 A including a shaft  15 A that houses a drive mechanism (not shown), and a first gear head  20 A. The gear head  20 A is attached to a free or distal end of the shaft  15 A and is rotatably coupled to the drive mechanism. Generally, the drive mechanism is driven by a prime mover (e.g., an engine or a motor) that is positioned adjacent an opposite end of the shaft  15 A. 
     The first gear head  20 A includes a first output shaft  25 A that is rotatably coupled to the drive mechanism, and that extends outward from the first gear head  20 A to define an axis of rotation  30 A. As shown in  FIG. 1 , the first output shaft  25 A is substantially cylindrical and has a first external diameter. In the illustrated construction, the first output shaft  25 A has a threaded external diameter. In other constructions, the first output shaft  25 A may have a substantially or completely unthreaded external diameter. 
       FIG. 2  illustrates a portion of another landscape trimmer  10 B including a shaft  15 B that houses a drive mechanism, and a second gear head  20 B attached to a free or distal end of the shaft  15 B and rotatably coupled to the drive mechanism. The drive mechanism described with regard to  FIG. 2  is similar to the drive mechanism described with regard to  FIG. 1 , and will not be discussed in detail. 
     The second gear head  20 B includes a second output shaft  25 B rotatably coupled to the drive mechanism, and extending outward from the second gear head  20 B to define an axis of rotation  30 B. As shown in  FIG. 2 , the second output shaft  25 B is substantially cylindrical and has a second external diameter. In the illustrated construction, the second output shaft  25 B has a threaded external diameter. In other constructions, the second output shaft  25 B may have a substantially or completely unthreaded external diameter. Referring to  FIGS. 1 and 2 , the second external diameter of the second output shaft  25 B is larger than the first external diameter of the first output shaft  25 A. Generally, the second output shaft  25 B has an external diameter that is different (e.g., smaller or larger) from the external diameter of the first output shaft  25 A. 
     Each of the landscape trimmers  10 A,  10 B also includes a string head  40 , a bump knob or retainer  45 , and an adapter  50 . The string head  40  is rotatably coupled to the respective gear head  20 A,  20 B via the adapter  50 , and includes a housing  55  for supporting cutting elements (e.g., monofilament line, rigid blades, etc.). In the illustrated construction, the housing  55  defines holes  60  (one shown) through which monofilament line can extend from within the housing  55 . 
     The housing  55  defines an aperture  65  that axially extends through the housing  55 . The housing has a body portion  70  and a connector portion or hub  75 , which extends away from the body portion  70  (i.e., upward in  FIGS. 1 and 2 ) proximate an end of the housing  55  and surrounds the aperture  65 . The body portion  70  supports the cutting elements and is coupled to the retainer  45 . 
     As shown in  FIGS. 1 and 2 , an outer diameter of the connector portion  75  substantially corresponds to an outer diameter of the respective gear head  20 A,  20 B to substantially completely cover or enclose the adapter  50 . The connector portion  75  defines a recess  80  that is proximate an inward or central part of the connector portion  75 , and the recess  80  is in communication with the aperture  65 . The recess  80  axially extends a predetermined depth into the housing  55 , and has a multi-faceted interior surface portion  85 . In the illustrated construction, the interior surface portion  85  defines a substantially hexagonally-shaped recess  80 . In other constructions, the recess  80  is defined by other multi-faceted shapes (e.g., rectangular, triangular, etc.). 
     The retainer  45  rotatably secures the string head  40  to the respective gear head  20 A,  20 B via the adapter  50 . Referring to  FIGS. 1 and 2 , the retainer  45  includes a knob portion  90  and a fastener portion  95  that extends axially outward from the knob portion  90  (i.e., upward in  FIGS. 1 and 2 ). The knob portion  90  is engageable by a user to selectively attach and detach the retainer  45  relative to the string head  40  such that the string head  40  may be assembled to and disassembled from the gear head  20 A and the gear head  20 B. The fastener portion  95  is substantially alignable with and extends into the aperture  65  to engage the adapter  50 . Other retainers that rotatably secure the string head  40  to the gear heads  20 A,  20 B are possible and considered herein. 
     As shown in  FIGS. 1 and 2 , the adapter  50  is coupled between the gear head  20 A,  20 B and the string head  40  such that rotation of the respective first and second output shafts  25 A,  25 B is transferred to the string head  40 . The adapter  50  includes an adapter body having a first end  100  and a second end  105  axially spaced apart from the first end  100 . The first and second gear heads  20 A,  20 B are coupled to the adapter  50  at the first end  100 , and the string head  40  is coupled to the adapter  50  at the second end  105 . 
     As shown in  FIG. 3 , the adapter  50  includes a string head portion  110  positioned proximate the second end  105 , a trimmer attachment portion  115  positioned proximate the first end  100 , and an intermediate portion  120  disposed on the adapter body between the string head portion  110  and the trimmer attachment portion  115 .  FIGS. 1-8  illustrate one construction of the adapter  50  in which the string head portion  110 , the trimmer attachment portion  115 , and the intermediate portion  120  are formed as a single piece to define a unitary adapter body.  FIG. 9  illustrates another construction of the adapter  50  in which the string head portion  110  is removably coupled to the intermediate portion  120 . In this construction, the string head portion  110  has an externally threaded portion  125  and the intermediate portion  120  has an internally threaded cavity  130  such that the string head portion  110  is threadably coupled within the intermediate portion  120 . 
     With reference to  FIGS. 3-6 , the string head portion  110  extends axially toward the first end  100  and couples the string head  40  to the adapter  50 . The string head portion  110  includes a substantially cylindrical outer surface  135  and defines an internally threaded cavity  140  ( FIG. 6 ) accessible from adjacent the second end  105 . The internally threaded cavity  140  extends axially toward the first end  100  of the adapter body to receive the fastener portion  95  of the retainer  45  and secure the string head  40  to the adapter  50 . 
     The trimmer attachment portion  115  of the adapter  50  is positioned opposite the string head portion  110 . The trimmer attachment portion  115  includes a generally cylindrical outer contour or surface  145 , and defines a hollow shaft  150  and a slot  155 . The hollow shaft  150  defines an opening  157  in the trimmer attachment portion  115 , and axially extends through the trimmer attachment portion  115  toward the second end  105  along the adapter body. The hollow shaft  150  further extends into the string head portion  110  to accommodate gear head output shafts (e.g., the first and second output shafts  25 A,  25 B) having different lengths, and intersects with the cavity  140 . Referring to  FIGS. 1 and 2 , the hollow shaft  150  is adapted to receive the respective first and second output shafts  25 A,  25 B. In the illustrated construction, the hollow shaft  150  defines an unthreaded opening  157 . In other constructions, the opening  157  may be at least partially threaded. 
     The slot  155  extends at least partially through the adapter  50  substantially transverse or orthogonal to and in communication with the hollow shaft  150 . As shown in  FIGS. 1-5 , the slot  155  extends completely through the adapter body substantially transverse to the respective axis of rotation  30 A,  30 B. The slot  155  is partially defined by a support surface  160 , and has a substantially rectangular cross section with a width W and a height H. As shown in  FIGS. 3 and 6 , the hollow shaft  150  extends through the support surface  160  axially along the adapter body. 
     As illustrated in  FIG. 1 , the slot  155  is adapted to receive a plurality of fasteners (e.g., nuts, clamps, pins, etc.) therethrough to removably couple different output shafts (e.g., the first output shaft  25 A and the second output shaft  25 B) to the adapter  50 . In the illustrated construction, the plurality of fasteners includes a first fastener  165 A having a first internal diameter, a second fastener  165 B having a second internal diameter that is different from the first internal diameter, and a third fastener  165 C having a third internal diameter that is different from the first and second internal diameters. Although three different fasteners  165 A,  165 B,  165 C are illustrated in  FIG. 1  and discussed herein, fewer or more than three fasteners (e.g., four or more fasteners) may be used with and selectively inserted into the adapter  50  within the slot  155 . 
     Each of the fasteners  165 A,  165 B,  165 C has an external diameter that is smaller than or substantially the same as the width W of the slot  155 . Each of the fasteners  165 A,  165 B,  165 C also has an internal diameter that corresponds to the external diameter of one output shaft (e.g., output shaft  25 A or output shaft  25 B) so that the string head  40  can be coupled to the corresponding output shaft via the adapter  50 . Generally, the size of the fasteners  165 A,  165 B,  165 C are variable within the dimensions permitted by the width W and the height H of the slot  155 . In particular, the external diameter of each fastener  165 A,  165 B,  165 C fits within the width W of the slot  155 , and the height of each fastener  165 A,  165 B,  165 C fits within the height H of the slot  155 . 
     The external diameter of each fastener  165 A,  165 B,  165 C may be the same as or different from the external diameter of the remaining fasteners  165 A,  165 B,  165 C. The internal diameter of each fastener  165 A,  165 B,  165 C is different from the internal diameters of the other fasteners  165 A,  165 B,  165 C to accommodate different output shafts. For example, one of the fasteners  165 A,  165 B,  165 C may include an internal diameter of approximately 12 millimeters. Other fastener sizes are also possible and considered herein. Referring to  FIGS. 1 and 2 , the internal diameters of the first, second and third fasteners  165 A,  165 B,  165 C are threaded to threadably couple to the corresponding output shaft. In other constructions, the fasteners  165 A,  165 B,  165 C may include unthreaded internal diameters (e.g., push nuts, etc.). 
     Referring to  FIGS. 1-5  and  8 , the intermediate portion  120  is configured for engaging the string head  40 , and has a surface  170  that defines a multi-faceted cross-section corresponding to the shape of the recess  80 . In the illustrated construction, the intermediate portion  120  includes a substantially hexagonal cross-section for indexing into the hexagonally-shaped recess  80  of the string head  40 . The intermediate portion  120  extends an axial distance D along the adapter  50  substantially corresponding to the depth of the recess  80  so that rotation of the adapter  50  is transferred to the string head  40 . 
       FIG. 3  illustrates an adapter member  180  that is engageable with the intermediate portion  120  to accommodate and couple different string heads (e.g., the string head  40 ) to the adapter  50 . The adapter member  180  accommodates string heads that have a relatively short axial height so that the retainer  45  may securely attach the string head  40  to the adapter  50 . The adapter member  180  also accommodates a string head having a different-sized recess so that the adapter  50  can couple the associated string head to the corresponding output shaft. 
     The adapter member  180  includes an adapter engagement portion  185  and a string head engagement portion  190  that axially extends away from the adapter engagement portion  185 . The adapter engagement portion  185  has a smooth outer contour or surface  195 , an internal recess  200  that axially extends partially through the adapter member  180 , and an aperture  205  that communicates with the internal recess  200  and receives the string head portion  110  therethrough. The external diameter of the adapter engagement portion  185  substantially corresponds to the external diameter of the trimmer attachment portion  115  so that the adapter  50  and the adapter member  180  may be substantially enclosed by the respective gear head  20 A,  20 B and the string head  40 . The internal recess  200  has a multi-faceted shape that corresponds to the shape of the intermediate portion  120  so that rotation of the adapter  50  is transferred to the adapter member  180 . In the illustrated construction, the internal recess  200  has a substantially hexagonal shape that corresponds to the hexagonal cross section of the intermediate portion  120 . Other shapes are possible and considered herein. 
     The string head engagement portion  190  has an external surface  210 , which is defined by a multi-faceted cross section corresponding to the shape of the recess  80  in the string head  40  to transfer rotation of the adapter  50  to the string head  40 . In the illustrated construction, the external surface  210  has a substantially hexagonal cross section. The string head engagement portion  190  extends away from the adapter engagement portion  185  an axial distance that corresponds to the depth of the string head recess  80  to substantially engage the string head  40  and to transfer rotation of the adapter  50  to the string head  40 . 
     Referring to  FIG. 1 , the landscape trimmer  10 A is assembled by attaching the string head  40  and the retainer  45  to the adapter  50 , and by attaching the adapter  50  to the first gear head  20 A. Referring to  FIG. 2 , the landscape trimmer  10 B is assembled by attaching the string head  40  and the retainer  45  to the adapter  50 , and by attaching the adapter  50  to the second gear head  20 B. The string head  40  is attached to the adapter  50  by inserting the string head portion  110  through the aperture  65  in the housing  55  and indexing the intermediate portion  120  with the string head  40  within the recess  80 . In constructions of the adapter  50  that include the removable string head portion  110 , the string head portion  110  may be removed from the intermediate portion  120  and replaced with another string head portion for attachment of the adapter  50  to another string head. Alternatively or in addition, the adapter member  180  can be attached to the intermediate portion  120  to accommodate other string heads. 
     The fastener portion  95  of the retainer  45  is threadably engaged with the internally threaded cavity  140  of the string head portion  110 , and the knob portion  90  is engaged to rotatably secure the string head  40  to the adapter  50 . For landscape trimmers that have string heads with relatively short axial heights and/or a different-sized recess, the adapter member  180  is engaged with the intermediate portion  120  prior to engaging the string head  40  with the adapter  50 . 
     With reference to  FIG. 1 , the adapter  50  is attached to or engaged with the output shaft  25 A by inserting the fastener  165 A into the slot  155  so that the adapter  50  can rotate with the first output shaft  25 A. The adapter  50  may be attached to other output shafts (e.g., the output shaft  25 B) by inserting corresponding fasteners (e.g., the fastener  165 B) into the slot  155 . For gear heads having output shafts with external diameters that are different from the external diameters of the output shafts  25 A,  25 B, other fasteners (e.g., the fastener  165 C) may be used to attach the adapter  50  to the corresponding output shaft. 
     After the fastener  165 A is inserted into the slot  155 , the output shaft  25 A is inserted through the hollow shaft  150  in the trimmer attachment portion  115  into the adapter body. The output shaft  25 A is rotatably attached or secured to the adapter  50  by the fastener  165 A. In the illustrated construction, the fastener  165 A is threadably engaged with the output shaft  25 A. In other constructions, the fastener  165 A may be engaged with the output shaft  25 A by other means (e.g., an interference fit between the fastener  165 A and the output shaft  25 A, a clamp connection between the fastener  165 A and the output shaft  25 A,etc.). In this manner, the string head  40  is rotatably engaged with the corresponding gear head  20 A via the adapter  50 . Other output shafts, including the output shaft  25 B, are coupled to the adapter  50  in a similar manner using the associated fastener (e.g., fastener  165 B). 
     The adapter  50  is a universal adapter that is usable with or interchangeable between gear heads (e.g., the gear heads  20 A,  20 B) that have output shafts with different external diameters and/or different lengths such that one string head (e.g., the string head  40 ) can be used with the different gear heads. For example, the string head  40  can be attached to either of the first gear head  20 A, the second gear head  20 B, or another gear head (not shown) by replacing or switching out the fastener  165  that is inserted into the trimmer attachment portion  115 . To switch the string head  40  from the first gear head  20 A to the second gear head  20 B, the first fastener  165 A is removed from the first output shaft  25 A (e.g., the first fastener  165 A is unthreaded from the first output shaft  25 A), and the first output shaft  25 A is removed from the hollow shaft  150 . The second fastener  165 B is inserted into the slot  155 , and the second output shaft  25 B is inserted into the hollow shaft  150  partially through the adapter body so that the second output shaft  25 B is rotatably secured to the adapter  50  via the second fastener  165 B. The string head  40  can be interchanged between other gear heads in a similar manner. 
     The adapter  50  provides a universal interface between the output shafts  25 A,  25 B of the first and second gear heads  20 A,  20 B and the string head  40  by receiving a plurality of fasteners that have different internal diameters and external diameters that are smaller than the width W of the slot  155  to allow insertion of the fasteners into the slot  155 . The different internal diameters of the fasteners  165  accommodate output shafts (e.g., output shafts  25 A,  25 B) that have different external diameters. The adapter  50  further provides a universal attachment of the string head  40 , or other string heads, to other landscape trimmers that have output shafts with different external diameters so that the string head  40  can be rotatably coupled to the desired gear head  20 . 
     Various features and advantages of the invention are set forth in the following claims.