Abstract:
A mold for a plastic grip of a portable tool has two halves with depressions forming the negative. The base body has a top grip extending, when mounted, across the topside of the housing perpendicularly to a longitudinal axis of the tool and a lateral grip connected to the top grip extending therefrom, when mounted, laterally downwardly. The top grip has a first end and the lateral grip has a second end for connecting to the housing. Top and lateral grips have identical elliptical cross-sections rotated to one another in the circumferential direction of the grip by an angle of rotation. Cross-sections have a first diameter larger than a second diameter. Mold depressions have recesses for molding elongate, raised portions in the longitudinal direction. Recesses are adjacent circumferentially and extend spirally. Separation surfaces of mold halves are positioned in a longitudinal center plane of a recess adjacent the first diameter.

Description:
This application is a Continuation-In-Part of application Ser. No. 08/900,101 of Jul. 25, 1997, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a grip for a portable, hand-guided working tool, especially a motor chainsaw, hedge clippers, a trimmer or cutoff device etc. with a base body molded in a two-part mold from a plastic material. The grip is positioned transversely to a longitudinal direction of the working tool at a distance above the housing. It has a top grip portion and a lateral grip portion connected thereto that extends laterally at a sidewall of the housing. The two ends of the base body are provided with connecting portions for securing the grip at the working tool. The grip portions have a substantially identical elliptical cross-section with a large and a small diameter. The cross-section of the top grip portion is positioned rotated in the circumferential direction of the base body relative to the cross-section. of the lateral grip portion so that the large cross-sectional diameter of the lateral grip portion is positioned in a different plane than the diameter of the cross-section of the top grip portion. 
     Such a grip is known from U.S. Pat. No. 5,245,757. It is comprised of a hollow base body with an elliptical cross-sectional shape which has a greater and a smaller cross-sectional diameter. In order to provide optimized gripping conditions for the user, the position of the cross-section is rotated along the length of the grip. Accordingly, the greater cross-sectional diameter of the lateral grip portion is positioned substantially perpendicularly to the plane which is defined by the guide rail of the motor chainsaw, while the cross-section of the upper grip portion is rotated relative to the cross-section of the lateral grip portion such that the greater cross-sectional diameter is positioned at an acute angle to the top side of the working tool. Such grips are produced in a two-part mold from plastic material and have been successfully used in practice. For providing sufficient grip, the mantle surface of the grip is roughened. 
     From U.S. Pat. No. 4,964,217 it is known to provide a plastic grip with an outer fluting in order to increase grip for the user. The fluting, however, can be embodied only relatively shallow because the grip otherwise could not be removed from the mold. 
     From German Gebrauchsmuster 94 11 866 a grip consisting of a profiled aluminum tube is known whereby the deep fluting insures good grip without negatively affecting comfort for the user. 
     It is therefore an object of the present invention to improve a grip of the aforementioned kind such that, while allowing easy removal from the two-part mold, a pronounced fluting is provided for increasing grip. 
     SUMMARY OF THE INVENTION 
     The inventive grip for a portable, hand-guided working tool according to the present invention is primarily characterized by: 
     a plastic base body molded in a two-part mold: 
     the base body comprising a top grip portion extending, when the grip is mounted on the working tool, across the top side of the housing of the working tool perpendicularly to a longitudinal axis of the working tool at a spacing to the top side of the housing so as to allow a user to grip the top grip portion; 
     the base body comprising a lateral grip portion connected to the top grip portion and extending from the top grip portion, when the grip is mounted on the working tool, laterally downwardly at a spacing to a sidewall of the housing so as to allow a user to grip the lateral grip portion; 
     the top grip portion having a first connecting end for connecting the grip to the housing; 
     the lateral grip portion having a second connecting end for connecting the grip to the housing; 
     the top grip portion having a first elliptical cross-section and the lateral portion having a second elliptical cross-section, wherein the first and second cross-sections are identical; 
     the cross-sections having a first and second diameter, the first diameter being larger than second diameter; 
     the first cross-section rotated relative to the second cross-section in a circumferential direction of the grip by an angle of rotation; 
     the base body having integral, elongate, raised portions, extending in a longitudinal direction of the grip and positioned adjacent to one another in the circumferential direction of the grip; 
     the raised portions extending slightly spirally along the top grip portion and the lateral grip portion; 
     wherein the two-part mold has mold seams, resulting from molding in the two-part mold, positioned within a longitudinal center plane of a respective one of the raised portions neighboring the first diameter. 
     Advantageously, the raised portions have a first end at the lateral grip portion and a second end at the top grip portion. The angular distance between the first and second ends measured in the circumferential direction of the grip is identical to the aforementioned angle of rotation. 
     The raised portions have a rounded outer contour in the circumferential direction of the grip. 
     The raised portions have different radii of curvature. 
     The raised portions neighboring the first diameter have a smaller radius than the raised portions neighboring the second diameter. 
     The raised portions in the circumferential direction are spaced at a small distance from one another. 
     The raised portions have different angular distances in the circumferential direction. 
     The angular distance is preferably 24° to 34°. 
     The raised portions neighboring the first diameter have a smaller angular distance than the raised portions neighboring the second diameter. 
     Advantageously, the respective raised portion neighboring the first diameter has a flattened part extending over the length of the respective raised portion. 
     The flattened part preferably extends to the end face of the first connecting end and to the end face of the second connecting end. 
     The flattened part is preferably positioned centrally relative to the respective raised portion. 
     Advantageously, the mold seam extends perpendicularly to the flattened part. The mold seams preferably extend in parallel planes. 
     Relative to the mounted position of the grip, one of the mold seams faces the working tool and another mold seam faces away from the working tool. 
     The base body is hollow and has a uniform minimum wall thickness in the circumferential direction. 
     The rotational change of the first cross-section into the second cross-section is uniform in the longitudinal direction of the grip. 
     Since the raised portions, that provide the profiling or fluting of the grip and extend in the longitudinal direction of the grip, are simultaneously being rotated over the length of the grip in a spiral, it is possible to position the mold seams of the mold, despite the rotating cross-section in the longitudinal direction, at the highest point of the cross-section. Thus, the mold seams of the mold (parting line of the mold) extend also in the form of a spiral in the longitudinal direction of the grip whereby the grip halves defined by the parting line or separation surfaces of the mold are free of an undercut. By separating the mold such that it has two slightly spirally extending mold joints or separation surfaces, an easy removal of the grip, despite the pronounced fluting of the elliptical grip with a cross-section that is rotated in the longitudinal direction of the grip, is possible. Preferably, the angular distance of the beginning point of a raised portion to the end point of a raised portion corresponds substantially to the rotational angle of the cross-section within the respective grip portions. Such an embodiment has been proven to be successful with respect to easy removal from the mold. 
     For increasing the comfort of the user, the raised portions have a rounded outer contour in the circumferential direction whereby the raised portions, depending on their position about the periphery, have different radii of curvature. Depending on their position about the periphery, the angular distances of the raised portions are also different in the circumferential direction in order to provide a comfortable grip fluting with good grip in any grip position. 
     Preferably, the projection or raised portion that is positioned in the parting plane of the mold is provided over its length with a narrow flattened part so that in the area of the mold joint the mold and the base body extend at a right angle to one another. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The object and advantages of the present invention will appear more clearly from the following specification in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a portable, hand-guided working tool with an inventive grip; 
     FIG. 2 is a plan view onto the working tool of FIG. 1; 
     FIG. 3 shows in an enlarged representation a plan view onto the grip according to FIG. 2; 
     FIG. 4 is a rear view of the working tool from the rear; 
     FIG. 5 is a side view onto the grip according to arrow V of FIG. 4; 
     FIG. 6 is a perspective representation of the grip according to FIG. 5 in the direction of arrow VI; 
     FIG. 7 is a front view onto the grip according to FIG. 5 in the direction of arrow VII; 
     FIG. 8 is a section along the line VIII—VIII of FIG. 7; 
     FIG. 9 is a view onto a connecting portion of the grip according to arrow VIII in FIG. 8; 
     FIG. 10 is a section along the line X—X of FIG. 9; 
     FIG. 11 is a Section along the line XI—XI of FIG. 7; 
     FIG. 12 is a schematic representation of the cross-section according to FIG. 11 in a manufacturing mold 
     FIG. 13 is a perspective view of the open mold showing the two mold halves; 
     FIG. 14 is a plan view of a first mold half; 
     FIG. 15 is a plan view of a second mold half; 
     FIG. 16A is a section along the line XVIA—XVIA of FIG. 14; 
     FIG. 16B is a section along the line XVIB—XVIB of FIG.  15 ; 
     FIG. 17A is a section along the line XVIIA—XVIIA of FIG. 14; 
     FIG. 17B is a section along the line XVIIB—XVIIB of FIG. 15; 
     FIG. 18A is a section along the line XVIIIA—XVIIIA of FIG. 14; 
     FIG. 18B is a section along the line XVIIIB—XVIIIB of FIG. 15; 
     FIG. 19A is a section along the line XIXA—XIXA of FIG. 14; 
     FIG. 19B is a section along the line XIX—XIX of FIG. 15; 
     FIG. 20A is a section along the line XXA—XXA of FIG. 14; 
     FIG. 20B is a section along the line XXB—XXB of FIG.  15 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention will now be described in detail with the aid of several specific embodiments utilizing FIGS. 1-20B. 
     The portable, hand-held working tool represented in FIGS. 1,  2 , and  4  is a motor chainsaw with a saw chain  2  circulating about the guide rail  1 . The guide rail  1  is clamped between the motor housing  3  and the cover  4  for the chain wheel, and extends substantially in the longitudinal direction  5  perpendicularly to the front end of the housing. The chain wheel cover  4  covers a chain wheel driven by a drive motor arranged within the motor housing  3  and driving the saw chain  2 . The drive motor can be an electric motor or an internal combustion engine. Preferably, it is a single cylinder, two-stroke engine. 
     At the housing side opposite the chain wheel cover  4 , the housing  3  is provided with a blower cover  6  of a cooling blower which provides the cooling airstream for cooling the internal combustion engine. 
     The backside of the motor housing  3  is provided with a rear grip  7  which is secured at the motor housing  3  by anti-vibration elements  8  and  9 . For this purpose, the rear grip  7  is provided with a fastening arm  10  at a portion adjacent to the actuating portion  7   a  which, in the longitudinal direction  5 , extends across the top side  11  of the housing and is secured by anti-vibration elements  8  and  9 . The fastening arm  10  is embodied, in the connecting area to the actuating portion  7   a  of the rear grip  7 , as a carburetor housing  12  in which an air filter as well as a carburetor for supplying the fuel/air mixture to the internal combustion engine are arranged. In the area of the actuating portion  7   a  operating elements  13  of the carburetor are arranged in the wall of the carburetor housing  12 . A throttle lever  14  as well as a throttle lever lock  15  are provided at the actuating portion  7   a.    
     For carrying and guiding the working tool, which may be in the form of hedge clippers, a cutoff device etc., a grip  20  is arranged at the forward area of the housing  3 . This grip  20  is comprised of a top grip portion  21  extending transverse to the longitudinal direction  5  of the housing which, see FIG. 1, spans at a distance a the top side  11  of the motor housing  3 . In the shown embodiment, the top grip portion  21  is positioned at an angle  16  of approximately 80° relative to the longitudinal axis  5 . Connected to the top grip portion  21  is a curved connecting portion  22  bent by approximately 90° which is connected to a lateral grip portion  23  extending substantially vertically and at a lateral distance spaced from the motor housing, respectively, the blower cover  6 . At the free ends of the plastic base body  25  connecting portions  26 ,  27  are provided with which the plastic grip  20  is connected to the working tool. The plastic material of the grip is preferably Durethan (trademark). 
     The connecting portion  26  connected to the free end of the top grip portion  21 , as is shown is FIGS. 6 and 7, is substantially U-shaped and engages with a plug  28  a connecting member  17  of the fastening arm  10  of the rear grip  7 . The connecting member  17  extends approximately at a right angle to the longitudinal axis  5  of the device at the side of the fastening arm  10  facing the chain wheel cover  4 . 
     The connecting portion  27  provided at the grip portion  23  is approximately shaped as a 90° bend and is fastened in the area of the front end of the housing in the vicinity of the motor housing bottom at the longitudinal side of the housing, preferably by a screw connection. For this purpose, a receiving opening  29  is provided within the connecting portion  27  in order to receive a fastening screw. 
     As can be seen especially in FIGS. 2 and 3, the connecting portions  26  and  27 , in a plan view, are positioned at a distance c to one another, whereby the connecting portion  27  of the lateral grip portion  23  is closer to the forward end of the housing than the connecting portion  26  of the top grip portion  21 , which is secured in the vicinity of the carburetor housing  12  at the fastening arm  10 . 
     A hand guard  18  is positioned adjacent to the top grip portion  21  and is secured in a pivotable manner at the motor housing  3 . It actuates a safety braking device arranged at the chain wheel cover  4  when the operator of the device slips from the grip  20  and hits the hand guard  18 . 
     As schematically shown in FIG.  1  and FIGS. 8,  10 , and  11  in cross-section, the base body  25  is hollow and has a wall thickness d which in the circumferential direction is preferably uniform. Especially the cross-section of the grip portions  21 ,  22 , and  23  has a non-circular cross-sectional contour, i.e., an elliptical cross-section with a greater diameter  31  and a smaller diameter  32 . The greater (first) diameter  31  is comparable to the larger axis of an ellipsoid. The smaller (second) cross-sectional diameter  32  corresponds to the smaller axis. The longitudinal grip axis  24  divides the smaller cross-sectional diameter  32  symmetrically. The greater cross-sectional diameter  31  is divided into a larger section  31   a  and a smaller section  31   b.  The smaller section  31   b  in the mounted state of the grip preferably faces the working tool. 
     As can be seen in the representation of FIG. 1, the cross-section  30  of the lateral grip portion  23  is positioned in a different rotational position relative to the longitudinal axis  24  of the grip (FIG. 5) than the cross-section  30  of the top grip portion  21 . As shown in FIG. 1, the cross-section  30  of the top grip portion  21  is rotated counter-clockwise relative to the cross-section  30  of the lateral grip portion  23  by an angle  19  in the circumferential direction such that the larger cross-sectional diameter  31  of the lateral grip portion  23  is positioned in a different plane than the greater cross-sectional diameter  31  of the cross-section  30  of the top grip portion  21 . The cross-sectional diameter  31  of the cross-section  30  of the lateral grip portion  23  extends substantially perpendicularly to the longitudinal side of the housing  3 . The longitudinal side extends parallel to the plane of the guide rail  1 . The larger cross-sectional diameter  31  of the cross-section  30  of the top grip portion  21  is positioned at an angle  19  to the plane defined by the top side  11  of the housing. The transition from the cross-sectional position of the cross-section  30  within the lateral grip portion  23  to the rotated cross-sectional position of the cross-section  30  within the top grip portion  2  is preferably uniform (continuous), especially over the length of the connecting portion  22 . 
     The grip portions  21  and  23  of the grip  20  have a fluting as shown in the Figures. The fluting is a unitary part of the base body  25  of the grip whereby preferably the connecting portions  26  and  27  are also a unitary part thereof. The profiling or fluting is comprised of a plurality of raised portions  40  to  45 ,  50  to  55  positioned in the circumferential direction adjacent to one another and extending in the longitudinal direction  24  of the grip. Each raised portion extends somewhat spirally along the grip portions  21  and  23  as well as the connecting portion  22 . The angular distance of a starting point  39  of the raised portion  42  to an end point  49  in the circumferential direction corresponds substantially to the rotational angle  19  between the cross-sections  30  of the top grip portion  21  and the lateral grip portion  23  (FIG.  6 ). The raised portions  40  to  45  and  50  to  55  extend at an angle  34  of approximately 3° transversely to the longitudinal direction  24 . As shown in FIGS. 8 and 11, each raised portion  40  to  45 ;  50  to  55  has a rounded outer contour  33  in the circumferential direction whereby the outer contour  33  of the raised portions  40  to  45 ,  50  to  55  have different radii of curvature R 5 , R 6 , R 7 , R 8 . It is advantageous to provide the raised portions  40 ,  45 ,  50 ,  55  neighboring the cross-sectional diameter  31  with a radius of curvature R 6  that is smaller than the radius of curvature for the raised portions  42 ,  43 ,  52 ,  53  neighboring the smaller cross-sectional diameter  32 . 
     Neighboring raised portions in the circumferential direction of the base body  25  have a minimal distance z or 2z (FIG. 11) relative to one another. The distances z are preferably of the same size. The angular width (angular distances  60  to  65  and  70  to  75 ) of the raised portions  40  to  45 ,  50  to  55  measured in the circumferential direction is different. The raised portions  40 ,  45 ,  50 ,  55  neighboring the larger cross-sectional diameter  31  have a smaller angular distance than the raised, portions  42 ,  43 ,  52 ,  53  neighboring the cross-sectional diameter  32 . 
     The angular distances are within a range of 24° to 34°. 
     The periphery of the cross-section  30  of the shown embodiment is divided into  12  sections (angular distances  60  to  65  and  70  to  75 ), whereby the angular distances  60  to  65  and the angular distances  70  to  75  when added result in an angle of 180°, respectively. As shown in FIG. 8, one of the raised portions of the angular distances  60  to  65  and  70  to  75  of the group that defines respectively the angular sum of 180° is provided with a flattened part  35  which is embodied as a narrow band at the upper side of the projections  40 , respectively,  50 . The flattened part  35  extends over the entire length of the raised portion  40 ,  50 . In the shown embodiment, the flattened part  35  extends also along the contour of the connecting portions  26 ,  27  (FIG.  8 ). The flattened part  35  is positioned substantially centrally on the raised portion  40 ,  50  and provides the highest level of the respective raised portion. 
     As represented in FIGS. 8,  10  and  12 , at the level of the flattened part  35  the mold seams  81 ,  82  of the manufacturing mold  80  for the grip  20  are provided. The mold joints of the mold  80  preferably extend perpendicularly to the flattened portion  35  over the entire length of the grip  20  approximately within the longitudinal center plane  36  of the raised portions  40 ,  50 . The dividing plane ( 81 ,  82 ). of the mold  80  extends along the corresponding raised portions  40 ,  50  over the entire length of the grip  20  in its longitudinal direction  24  in a slight spiral. By selecting the location of the mold joints or mold separation surfaces as disclosed, a simple removal from the manufacturing mold  80  is possible despite the pronounced fluting of the grip sections  21 ,  23  as well as of the connecting sections  22 . The selected shape of the cross-section  30 , the selected shape of the projections  40  to  45  and  50  to  55  as well their selected width and position ensure proper opening and closing of the mold  80  comprised of two mold halves  83 ,  84  (see FIG. 13) for producing the grip  20 . The mold seam  81  faces the working tool, while the mold seam  82  faces away from the working tool. The mold seams  81  and  82  are positioned at a distance parallel to one another. They do not provide a plane of symmetry of the cross-section  30 . 
     The mold  80  for manufacturing the grip  20  is shown in a perspective view in FIG. 13 in the open state. It is comprised of two halves  83  and  84  having facing separation surfaces  83 ′,  84 ′ that produce the mold seams  81  and  82  at the grip  20  and define separating lines of the grip  20 . The mold halves  83 ,  84  each have a depression  20   a,    20   b  which combined define the negative for the grip  20  to be formed. 
     Since the grip  20  has raised portions  40 - 45  and  50 - 55  (see FIG. 11) in its longitudinal direction which in the longitudinal direction extend spirally, the location of the parting plane or separation surfaces  83 ′,  84 ′ of the mold  80  is of utmost importance for the removal of the grip  20  from the mold  80 . 
     As can be seen in, FIGS. 13 to  15 , the separation surfaces are not flat or planar (two-dimensional) but a three-dimensional plane. The separation surfaces  83 ′,  84 ′ divide the cross-section  30  of the grip  20  always in the longitudinal center plane  36  of the raised portions  40 - 4 ,  50 - 55  located adjacent to the greater diameter  31  (FIG.  12 ). In FIGS. 16A to  20 B the location of the separation planes  83 ′,  84 ′ is illustrated in a sequence of cross-sections  30  taken in the longitudinal direction of the grip  20  (see FIGS. 14 and 15 for their position relative to the grip  20 ). The depressions  20   a,    20   b  when combined form the negative of the grip  20  and thus have longitudinal recesses  40   a - 45   a,    50   a - 55   a  matching the raised portions  40 - 45  and  50 - 55 . These recesses  40   a - 45   a,    50   a - 55   a  thus extend spirally in the longitudinal direction of the depressions  20   a,    20   b  of the mold halves  83 ,  84  whereby the separation surfaces  83 ′,  84 ′ are respectively positioned in the longitudinal center plane  36  of the raised portions  40 ,  50 , respectively, the longitudinal center plane of the recesses  40   a,    50   a  positioned adjacent to the greater diameter  31  of the cross-section  30  (see FIG.  12 ). Since the separation surfaces  83 ′,  84 ′ are thus always positioned in the longitudinal center plane  36  of the raised portions  40 ,  50 , respectively, the recesses  40   a,    50   a,  the separation surfaces  83 ′,  84 ′ are rotated in the longitudinal direction of the grip  20  or the depressions  20   a,    20   b  in the mold halves  83 ,  84  according to the rotational angle R (spiral angle) of the raised portions  40 - 45 ,  50 - 55  of the grip  20  or the recesses  40   a - 45   a,    50   a - 55   a  of the mold  80 . 
     The present invention is, of course, in no way restricted to the specific disclosure of the specifications, and drawings, but also encompasses any modifications within the scope of the appended claims.