the present invention overcomes these problems with a roll - up leash of the above mentioned type which is designed in such a way that it has the simplest possible structure and will work reliably for as long as required . the invention overcomes existing drawbacks by means of a roll - up leash having the features disclosed in the characterising part of claim 1 . the depending claims outline advantageous features of the invention . this type of extending dog leash has a considerably simpler structure than that according to the aforementioned patent ep - b1 - 1204312 as it does not require any sort of toothed wheels . it is therefore cheaper to manufacture and does not make any noise whatsoever when winding and unwinding the dog leash because there are no toothed wheels engaging in each other or unwinding and as no catches have to rattle over a catch toothing . compared to the cord - type starting device according to the previously assessed de - 1476514 , the roll - up leash according to this invention has the advantage that no mechanical friction is required to brake the rotating actuator which means there is no wear and tear and there is no undesired heat build - up . in a further embodiment , the roll - up leash has a particularly simple design where a magnet for generating an axial force directed towards the casing is mounted on the rotating actuator . this also makes assembly easier , as the rotating actuator just has to be inserted into casing and is held in place there by the magnetic force alone . the catches can also be extended and retracted without contact and thus without friction and wear and tear if , according to another embodiment of the invention , the means of extending and retracting the catch consist of two magnets with opposite poles , positioned one after the other in the direction of rotation of the rotating actuator , and a magnet in the catch , so that , in rest position , the catch is attracted by the first magnet of the rotating actuator and , when the leash winds out , the catch is pushed out by the second magnet of the rotating actuator . the same magnets can be used for extending and retracting the catches and for braking the rotating actuator if the magnets in the rotating actuator at the same time serve to generate the polar force directed axially towards the casing by means of a metal ring positioned in the casing opposite the magnets . it is also possible to extend and retract the catches using mechanical means . the means of extending and retracting the catch in this case consists of an outward facing arm on the rotating actuator and a slanted surface on the catch which moves towards the arm . if the winding drum rotates at high speed when the dog leash is winding up , the catch tends to turn outwards because of the centrifugal force . in that case it would not block the winding drum , but rather slide over the manually operated catch stop and thus cause undesirable noise . this can easily be prevented according to another further embodiment of the invention , whereby the rotating actuator has an arrester hook which latches radially over the catch when the catch is retracted . the button to release the dog leash can be locked in the release position so that the user does not need to constantly hold it down to allow the dog the freedom determined by the length of the dog leash if the button for the stop , from its position pressed into the casing is transversely mobile to the button &# 39 ; s direction of retraction with a click projection under a casing stop . it is particularly advantageous if the button lies against the end of a single - arm lever , which biases the button away from the casing stop and if the single - arm lever at the same time lies against a lever arm of a two - armed lever , whose other lever arm engages in the mobile catch stop . with this type of design the button tends to move away from the casing stop with its click projection . therefore , if the user just taps it in its pressed down , locked position , then it will be released from the casing stop and can fully reach its extended position . the invention allows various embodiments . in order to elucidate its basic principle two of these are shown in the drawings and are described below . the drawings show in fig1 a cross - section of a major area of a roll - up leash according to the invention in locked position ; fig2 a cross - section of a top area of the roll - up leash in release position ; fig3 a section of the top half of the roll - up leash rotated through 90 ° compared to fig1 ; fig4 a section of the area of a button on the roll - up leash to lock and release the dog leash ; fig5 a diagram of the winding drum with the adjacent components in locked position ; fig6 a diagram of the winding drum in release position ; fig7 a longitudinal section of the roll - up leash in the winding drum area ; fig8 a diagram of a second embodiment of the winding drum with the adjacent components in locked position ; fig9 the arrangement according to fig8 in the release position . as shown in fig1 , the roll - up leash according to the present invention has a substantially cylindrical casing 1 containing a winding drum 3 , pivoting about an axis 2 , on which a leash 4 can wind and unwind . the casing 1 has , in the right area of fig1 , an integrally moulded grip 17 which is cut off in the drawing . on one side of the winding drum 3 there are , for example , three catches , of which only one catch 5 is depicted , to keep a swivel axis 6 provided on winding drum 3 turnable . each catch 5 has a cam 7 , which , in the depicted , swivelled out position of the catch 5 , lies against a catch stop 8 . the catch stop 8 is positioned so that it is radially mobile in the casing 1 and is biased by means of a pressure spring 9 in the direction of the winding drum 3 . a two - armed lever 10 serves to move the catch stop 8 against the force of the spring 9 . this has a lever arm 11 , which engages in the catch stop 8 and a lever arm 12 , which catches under a single - arm lever 13 . to turn the single - arm lever 13 , a button 14 is used , which , for this purpose , can be moved into the grip 17 of the casing 1 . the button 14 has a click projection 15 , which can , when the button 14 is in a pressed down and moved to the left position as seen in fig1 , latch into a casing stop 16 , which is shown in fig2 . as shown in fig2 , the button 14 with its click projection 15 rests in the casing stop 16 . this will have caused the lever arm 11 to push the catch stop 8 outwards out of the direction of travel of the catches 5 which means that the winding drum 3 can now rotate freely in both directions of rotation . fig3 shows the winding drum 3 with the leash 4 wound around it . there is also a diagram of a spiral spring 18 , which biases the winding drum 3 in the direction of winding . on the left side of the winding drum 3 , the catch 5 which lies against the catch stop 8 is clearly visible . fig4 illustrates the design of the button 14 which can turn the lever 13 . the function of the roll - up leash according to this invention is clearly visible in fig5 and 6 . fig5 shows that on the axis 2 a rotating actuator 19 is pivoted , which lies with a nib 20 against a stop 21 of the winding drum 3 . the winding drum 3 has another stop 22 , which can , when the winding drum 3 rotates relative to the rotating actuator 19 in an anti - clockwise direction , get from the opposite side to the nib 20 . in the catch 5 there is a magnet 23 , which , in the position shown in fig5 , lies opposite a magnet 24 of the rotating actuator 19 . the magnets 23 , 24 are magnetised in such a way that opposite poles are facing each other . this means that the magnets 23 , 24 mutually attract each other . this holds the catch 5 in the depicted , swivelled - in position . if the winding drum 3 rotates anti - clockwise relative to the rotating actuator 19 , then the magnet 23 will finish in the rotating actuator 19 via a second magnet 25 . this second magnet 25 is magnetised in such a way that the same poles are opposite each other with magnets 23 , 25 so that a repulsive force is exerted on the catch 5 . fig5 shows the position of the components when the leash 4 winds in . fig6 on the other hand shows the position when a dog on the leash wants to move away from its owner and the leash unwinds . the catch 5 then ends up with its cam 7 against the catch stop 8 shown in fig1 and 3 . a relative rotation between the rotating actuator 19 and the winding drum 3 is therefore required for the functioning of the roll - up leash . how this is accomplished can be seen in fig7 . fig7 shows the casing 1 with the axis 2 which is directly moulded onto the casing 1 . the winding drum 3 is pivoted on this axis 2 and , for its part , holds the catch 5 swivel - mounted with the magnet 23 . the rotating actuator 19 , of which the magnet 24 can be seen in fig7 , is also pivoted on a collar 26 of the casing 1 . axially opposite the magnet 24 and other magnets 27 of the rotating actuator 19 there is an iron ring 28 fixed in the casing and positioned coaxially to the rotating actuator 19 . magnets 24 , 27 and the iron ring 28 impede a twisting of the rotating actuator 19 on the collar 26 . with the embodiment according to fig8 and 9 , the rotating actuator 19 has three diagonally outward facing arms 29 , 30 , 31 . these arms 29 , 30 , 31 catch , as will now be explained for the arm 29 , by means of a recess 32 of the catch . if the winding drum 3 rotates clockwise , the arm 29 lies against a stop 33 , represented by the left edge of the recess 32 seen in fig8 . on the right side , the recess 32 is restricted by a slanted surface 34 . if the winding drum 3 rotates anti - clockwise , as is the case when the cord 4 unwinds , then this slanted surface 34 ends up against the arm 29 . as the rotating actuator 19 is more difficult to turn than the winding drum 3 , the arm 29 pushes the catch 5 outwards , as shown in fig9 , thereby locking the roll - up leash . fig8 and 9 also show that the arms 29 , 30 , 31 each feature at their free end an arrester hook 35 , which , in the position shown in fig8 — winding in the dog leash 8 — catches over the stop 33 and thus prevents the catches 5 , because of the centrifugal force , from getting outside . this type of arrester hook 35 could also be provided with the embodiment according to fig1 - 7 . it should be noted that the roll - up leash according to this invention can also be used for other purposes such as a cord - type starter .
a roll - up leash which comprises a casing containing a winding drum , pivoting around an axis , biased in the direction of winding . this winding drum has at least one catch which , when the leash unwinds , automatically extends outwards towards a catch stop . this catch stop can be moved back , by means of a manually operated button , out of the direction of travel of the extended catch . the catch is positioned swivel - mounted on an end face of the winding drum . to turn the catch there is a rotating actuator revolving with the winding drum but limited relative to the same and having , to synchronise the rotating actuator after passing an idle clearance of the rotating actuator relative to the winding drum , two stops , and with the rotating actuator featuring means to extend and retract the catch in the case of rotation relative to the winding drum . to prevent the rotary motion of the rotating actuator , at least one magnet is positioned between the casing and the rotating actuator .