Coupling element

Abstract

A coupling element is provided for a detachable plug connection of a guide tube, which is dividable into at least two sections, with a drive shaft mounted therein for torque transmission between an engine unit and a tool head of a hand-operated string trimmer. A first, upper guide tube section is arranged between the engine unit and the coupling element, and a second, lower guide tube section is arranged between the coupling element and a tool head. The coupling element has a coupling sleeve that provides both an exact alignment of the cutting tool as well as a simple and secure assembly of the guide tube sections. A latching connection with at least one latching element is arranged on the coupling sleeve so that it latches into place in only the correct rotational position on a latching seat of the guide tube section upon insertion of one of the guide tube sections into the coupling sleeve.

1 . A coupling element for a detachable plug connection of a guide tube, which is dividable into at least two sections, with a drive shaft mounted therein for torque transmission between an engine unit and a tool head of a hand-operated string trimmer, comprising:
 a first, upper guide tube section arranged between the engine unit and the coupling element;   a second, lower guide tube section arranged between the coupling element and the tool head, wherein the coupling element has a coupling sleeve; and   a latching connection having at least one latching element arranged on the coupling sleeve, said latching element being designed in such a manner that it latches in place in only the correct rotational position when one of the guide tube sections is inserted into the coupling sleeve on a latching seat of the guide tube section.   
   
   
       2 . The coupling element as specified in  claim 1 , characterised in that the latching element and the latching seat are designed in such a manner that the latching connection engages only in a rotational and axial position of the guide tube section. 
   
   
       3 . The coupling element as specified in  claim 1 , characterised in that the latching element is designed as a latching lug with an elastic latching arm, and furthermore in that the latching seat is configured as a receiving opening of the latching lug, said receiving opening being present on the guide tube section. 
   
   
       4 . The coupling element as specified in  claim 3 , characterised in that the latching lug is guided on the coupling sleeve in an axially displaceable manner, and moreover works together with a receiving opening of an adjacent platform in such a manner that upon insertion of the guide tube section, the latching lug moves axially on the platform and is raised until the receiving opening is engaged by the latching lug and is inserted thereinto. 
   
   
       5 . The coupling element as specified in  claim 3 , characterised in that an external actuating part, which is axially displaceable on coupling sleeve is integrally formed on the end of the latching arm that is opposite the latching lug for disconnecting the latching connection. 
   
   
       6 . The coupling element as specified in  claim 5 , characterised in that the actuating part with its latching arm and its latching lug is manufactured out of a plastic. 
   
   
       7 . The coupling element as specified in  claim 3 , characterised in that the latching lug has a substantially trapezoidal cross-section that tapers in the direction of the drive shaft. 
   
   
       8 . The coupling element as specified in  claim 1 , characterised in that the guide tube section that works together with the latching element is the lower section. 
   
   
       9 . The coupling element as specified in  claim 1 , characterised in that additionally at least one screwed clamping connection for the clamping connection of the coupling sleeve is present on the guide tube section. 
   
   
       10 . The coupling element as specified in  claim 9 , characterised in that the screwed clamping connection comprises a tooless gripper clamp with a tommy screw or a thumb screw. 
   
   
       11 . The coupling element as specified in  claim 1 , characterised in that a shaft coupling for transmitting the power of the drive shaft is arranged in the coupling sleeve. 
   
   
       12 . The coupling element as specified in  claim 11 , characterised in that the latching connection is designed in such a manner that it engages only if the shaft coupling engages both of the to-be-coupled shaft ends of the drive shaft. 
   
   
       13 . The coupling element as specified in  claim 11 , characterised in that the shaft coupling comprises a shaft sleeve fastened on one shaft end, the edges of said shaft sleeve being provided with radial, rotationally symmetrical slits in order to connect a star-shaped shaft end of a to-be-coupled shaft end in a form-fitting manner. 
   
   
       14 . The coupling element as specified in  claim 13 , characterised in that the shaft sleeve consists of two or a plurality of sleeve sections divided in such a manner that they are held on a shaft end by circumferential clamp rings. 
   
   
       15 . The coupling element as specified in  claim 1 , characterised in that the latching connection is designed in such a manner that the latching element is displaceable on the coupling sleeve. 
   
   
       16 . The coupling element as specified in  claim 15 , characterised in that the latching connection can be clipped onto the coupling sleeve. 
   
   
       17 . The coupling element as specified in  claim 16 , characterised in that the latching connection is designed in such a manner that it is independently springs back on the coupling sleeve.