fig1 shows a needle protecting device in its assembled state . a plug - on sleeve 2 , a covering sleeve 10 and a needle protecting sleeve 20 in a co - axial arrangement may be recognized . the covering sleeve 10 is latched onto the plug - on sleeve 2 . the latching connection can practically no longer be released . when assembled , the plug - on sleeve 2 and the covering sleeve 10 can be regarded as a single base body 2 , 10 . no sliding movements are possible , in particular between the plug - on sleeve 2 and the covering sleeve 10 . the needle protecting device may be plugged onto an injection device for administering a product fluid , in particular a medicinal fluid , for example insulin . to this end , the plug - on sleeve 2 is formed adapted to the injection device in question . the needle protecting sleeve can be slid back and forth in the axial direction within the covering sleeve 10 . in fig1 , it assumes a protective position . in the protective position , the needle protecting sleeve 20 is extended up to a stopper formed within the covering sleeve 10 and surrounds an injection needle of the injection device up to and beyond a tip of the needle . in the protective position , the needle protecting sleeve 20 protects the user from injuries from the injection needle . at the same time , the injection needle is protected from being damaged . in the protective position , the needle protecting sleeve 20 furthermore forms a blind , such that the user cannot see the injection needle . in particular , this reduces the inhibition threshold to be observed in users who inject the product themselves . in the protective position , the needle protecting sleeve 20 is blocked against sliding into the covering sleeve 10 . this blocking prevents the needle protecting sleeve 20 from being unintentionally retracted and the injection needle exposed . directly before an injection , the user has to release the block on the needle protecting sleeve 20 , i . e . he has to release the safety on the needle protecting sleeve 20 . this is done by axially sliding an operating element 36 . once the block is released , the needle protecting sleeve 20 can be retracted , against an elastic restoring force relative to the plug - on sleeve 2 and the covering sleeve 10 , into a distal position . in the distal position , the needle protecting sleeve 20 exposes the injection needle . the needle protecting sleeve is retracted in the course of insertion during the injection . if the injection needle is withdrawn again out of the tissue after the injection , the needle protecting sleeve 20 is advanced again by the elastic restoring force . as soon as the needle protecting sleeve 20 has reached its protective position again , it is automatically re - blocked . the block can be repeatedly released . fig2 and 4 show the components of the needle protecting device individually , before being assembled . the needle protecting device is formed by five components , namely the plug - on sleeve 2 , the covering sleeve 10 , the needle protecting sleeve 20 , a safety - release means 30 and a restoring element in the form of a pressure spring 29 , which however is only shown in fig5 . in one embodiment , however , once these five components have been assembled , the operating element 36 still has to be connected to the safety - release means 30 . the four components 2 , 10 , 20 and 30 and also the operating element 36 are each embodied in one piece as plastic injection parts . the plug - on sleeve 2 comprises a whole , distal sleeve region 3 and a proximal sleeve region comprising two sleeve segments 7 and a ring 8 . the two sleeve segments 7 project from a proximal facing area of the distal sleeve region 3 , offset by 180 °. the two sleeve segments 7 are distanced from each other at their proximal ends by the ring 8 and thus the proximal sleeve region is reinforced . in a transition region between the distal sleeve region 3 and the sleeve segments 7 , a recess or groove 4 is formed circumferentially . lastly , the two sleeve segments 7 each comprise a tangentially extending swelling or bulge 6 near their distal ends on their outer surface areas . the covering sleeve 10 comprises a surface area which is broken only by two opposing openings 14 . in the vicinity of the distal end of the covering sleeve 10 , a swelling or bulge 13 runs around the inner surface area . in the assembled state , the bulge 13 comes to rest in the groove 4 of the plug - on sleeve 2 . at the proximal end of the covering sleeve 10 , two collar segments 15 project radially inwards . the two collar segments 15 serve as front stoppers and as linear guides for the needle protecting sleeve 20 . on the inner surface area of the covering sleeve 10 , two stoppers 16 are formed in a symmetrical arrangement and offset by 180 ° with respect to each other . the stoppers 16 are each formed by a pair of areas facing the proximal end of the covering sleeve 10 and pointing radially to the inner surface area of the covering sleeve 10 . viewed in the axial direction , the stoppers 16 are arranged between the openings 14 and the collar segments 15 . furthermore , two straight , axially extending channels 17 are formed in the inner surface of the covering sleeve 10 . each one of the openings 14 extends through one of the channels 17 and sub - divides the respective channel into a distal channel section 17 a and a proximal channel section 17 b . the stoppers 16 directly border the proximal channel section 17 a of each of the channels 17 and thus each form one edge of the channel edging . a distal inner surface region 11 of the covering sleeve 10 is extended toward a proximal inner surface region 12 . the transition is formed by a circumferential collar interrupted by the channels 17 . the needle protecting sleeve 20 exhibits the shape of a cap , by forming a base at its proximal end , said base being broken only by a central opening 21 for the injection needle . two latches 24 , axially free , project from a distal facing area of the needle protecting sleeve 20 in a symmetrical arrangement and offset by 180 °. the latches 24 each radially protrude slightly beyond an outer surface area of the needle protecting sleeve 20 . the latches 24 are each formed in an exposed notch 25 of the surface area of the needle protecting sleeve 20 . in one embodiment , the latches 24 are each laminate . in one embodiment they are rectangular laminae . in another embodiment , the latches are a single layer . at their rear ends , the latches 24 are tapered or angled in a central region 26 on their outward pointing upper sides . the latches 24 are elastic in the radial direction around their foot regions . lastly , the needle protecting sleeve 20 comprises a recessed face region 22 on its outer surface area , said face region 22 tapering off towards the proximal end of the needle protecting sleeve 20 and forming a collar 23 to the rest of the outer surface area at its distal end . another recessed face region 22 is formed in the same way on the diametrically opposing side of the needle protecting sleeve 20 . the safety - release means 30 is formed by a ring 31 and two tongues 32 projecting axially from the ring 31 and arranged symmetrically , offset by 180 ° with respect to each other . a recess or groove 34 runs around the inner surface area of the ring 31 . a cam 35 projects outwards from each of the outward pointing surfaces of the tongues 32 . an operating element 36 is attached to each of the cams 35 . in one embodiment , the operating elements 36 are only attached to the cam 35 after the four components 2 , 10 , 20 , 30 have been assembled . when assembling the device , the needle protecting sleeve 20 is first pushed into the covering sleeve 10 . the two collar segments 15 together with the recesses 22 form a linear guide for the needle protecting sleeve 20 . the co - operation between the collar segments 15 and the two recesses 22 simultaneously ensures that as soon as it is inserted , the needle protecting sleeve 20 assumes a rotational position relative to the covering sleeve 10 such that the latches 24 are aligned with the stoppers 16 . due to their radially projecting length in the proximal inner surface region 12 of the covering sleeve 10 , the latches 24 are bent radially inwards against their own elastic restoring forces . as soon as the latches 24 have been pushed over the stoppers 16 , they pre - latch radially outwards again due to their own elastic restoring forces , such that their distal facing areas then oppose the stoppers 16 , directly facing them . in this blocking mesh ( i . e ., engagement , connection , etc .) of the latches 24 , it is no longer possible to retract the needle protecting sleeve 20 relative to the covering sleeve 10 . the latches 24 then lie in front of the stoppers 16 in an enlargement 18 of the channel section 17 b of the covering sleeve 10 . more precisely , only the edge regions of the latches 24 remaining to the left and right of the angled central region 26 push against the stoppers 16 in the blocking mesh . if the needle protecting sleeve 20 is advanced slightly further , then the collars 23 push against the collar segments 15 . the co - operation between the collar segments 15 and the collars 23 is principally intended to prevent the needle protecting sleeve 20 from being able to fall forwards out of the covering sleeve 10 . the latches 24 are , however , still accessible from without , from the proximal facing side of the covering sleeve 10 using a pointed tool . in the next assembly step , the safety - release means 30 , in the rotational position relative to the other components as shown in fig3 , is likewise pushed into the covering sleeve 10 , behind the needle protecting sleeve 20 . as it is inserted , the tongues 32 are guided tightly and laterally into the channels 17 . insertion is complete when the cams 35 reach the region of the openings 14 and the tongues 32 are therefore able to pre - latch outwards . the operating elements 36 are then adhered to the cams 35 or securely attached in some other way . the operating elements 36 are shaped such that they press against the outer surface area of the covering sleeve 10 and so keep any radial pressure during operation off the tongues 32 . the operating elements 36 thus also simultaneously serve to support the safety - release means 30 and / or the tongues 32 on the covering sleeve 10 . the operating elements 36 can also be formed as one piece on the cams 35 , for example mushroom - shaped . in such an embodiment , they would be placed against the respective cam once they have been passed through the openings 14 and once passed through would elastically expand , in particular shore up , to achieve the support . before the covering sleeve 10 is connected to the plug - on sleeve 2 , the pressure spring 29 ( fig5 ) is inserted into the pre - assembled needle protecting sleeve 20 as far as the base of the needle protecting sleeve 20 . in a last assembly step , the covering sleeve 10 , comprising the components 20 and 30 and the pressure spring 29 , is pushed onto the plug - on sleeve 2 until the bulge 13 is locked into the groove 4 . since the covering sleeve 10 is not broken in the region of the bulge 13 , and due to a sufficient rigidity overall , the locking connection between the groove 4 and the bulge 13 cannot be released again , at least not without tools or without destroying it . if the safety - release means 30 does not yet assume the locking position shown in fig5 , then the needle protecting sleeve 20 can be retracted into its distal position , for example within the context of functional testing by the manufacturer . the needle protecting sleeve 20 presses the safety - release means 30 into the distal locking position such as the safety - release means 30 assumes in the representation in fig5 . the safety - release means 30 is slaved by the needle protecting sleeve 20 pressing with a distal facing side 27 against a facing side 33 of the safety - release means 30 facing towards it . the two bulges 6 meshing with the groove 34 of the safety - release means 30 establishes a releasable locking connection . the locking connection is nonetheless sufficiently firm to prevent it being released due to the vibrations , jerking and the like which commonly occur during use . the function of the needle protecting device is best seen from fig5 and 6 . fig5 shows the needle protecting device completely assembled and attached to an injection device ( not shown ). the plug - on sleeve 2 surrounds an ampoule holder 1 . the ampoule holder 1 is sleeve - shaped and accommodates an ampoule which is filled with a medicine fluid . the ampoule holder 1 is inserted into the plug - on sleeve 2 up to the ring 8 . the segments 7 ( fig3 ) allow the ampoule holder 1 to be viewed . an injection needle 40 connected in the usual way to an outlet of the ampoule protrudes beyond the proximal ends of the plug - on sleeve 2 and of the covering sleeve 10 . in the representation in fig5 , the needle protecting sleeve 20 assumes its protective position , in which it protectively surrounds the injection needle 40 over its entire length . the latches 24 oppose their respective stopper 16 , facing them axially , i . e . they abut their respective stopper 16 . the safety - release means 30 assumes its locking position , in which there is no mesh ( i . e ., engagement , connection , etc .) between the tongues 32 and the latches 24 . the needle protecting sleeve 20 is thus blocked against retracting . an annular space 9 is formed between the sleeve segments 7 and the covering sleeve 10 , into which space the needle protecting sleeve 20 can be slid up to its distal position if the blocking mesh between the latches 24 and the stoppers 16 has been released beforehand . this is released by sliding the safety - release means 30 in the proximal direction . in the following , the functional sequence in an injection will be described , wherein reference is to be made at all times to all the figures . once a protective cap still surrounding the injection needle 40 has been removed , a first injection can be performed . directly before the injection , the user pushes the safety - release means 30 in the proximal direction by means of the operating elements 36 . in the course of sliding the safety - release means 30 , each of the tongues 32 slides over the latch 24 assigned to it . since the latches 24 protrude outwards beyond the sliding contact areas of the tongues 32 facing them , the latches 24 are pressed radially inwards when the tongues 32 slide past the latches 24 with their sliding contact areas . the safety - release means 30 is advanced as far as a proximal end position , wherein the latches 24 are bent away from the stoppers 16 , such that the needle protecting sleeve 20 can be pushed into the annular space 9 , the latches 24 pressing elastically against the tongues 32 . the tongues 32 are as wide as the tapered or angled central regions 26 ( fig3 ) of the latches 24 . the tongues 32 are likewise tapered towards their proximal facing areas . tapering the latches 24 or the tongues 32 or both particularly securely prevents self - locking which could impede sliding over the latches 24 . once the block on the needle protecting sleeve 20 has been released , the injection device is placed on the skin , such that the needle protecting sleeve 20 lies on the skin via its base and the injection needle 40 points to the surface of the skin approximately perpendicularly . in this injecting position , the needle protecting sleeve 20 is slid into the annular space 9 as far as a distal position by the pressure of the injection device against the surface of the skin . simultaneously , the injection needle 40 pierces the skin and penetrates into the tissue below . as the needle protecting sleeve 20 is slid into the annular ring 9 , a distal facing area 27 ( fig2 ) of the needle protecting sleeve 20 meshes with the facing area 33 of the safety - release means 30 . the mesh consists of a loose abutting of the two facing areas 27 and 33 . in this way , the needle protecting sleeve 20 presses the safety - release means 30 into the locking position shown in fig5 , in which the two bulges 6 mesh with the recess 34 . if , after the injection , the injection needle is withdrawn from the tissue again and the needle protecting device is relaxed , then the needle protecting sleeve 20 slides back in the proximal direction due to the force from the pressure spring 29 . as the needle protecting sleeve 20 is moved , the safety - release means 30 remains in its locking position . as soon as the needle protecting sleeve 20 has been advanced far enough that the latches 24 pass in front of the stoppers 16 , the latches 24 latch back radially outwards due to the restoring forces generated in them by being bent away , such that they again oppose the stoppers 16 and the blocking mesh is re - established . the injection device can be disposed of together with the needle protecting sleeve in its blocked protective position . even in the case of repeated injections , the needle protecting device likewise fulfills its protective function . lastly , the needle protecting device can also be used in combination with a number of injection devices in succession . in principle , it can even be used with various injection devices in an embodiment as a plug - on device , if the plug - on sleeve 2 is adapted in its shape to the respective injection device . for the majority of injection devices , it can be assumed that the ampoules exhibit approximately the same cross - sections , such that it is only actually necessary to adapt the plug - on sleeve 2 . in the foregoing description , embodiments of the invention have been presented for the purpose of illustration and description . it is not intended to be exhaustive or to limit the invention to the precise form disclosed . obvious modifications or variations are possible in light of the above teachings . the embodiments were chosen and described to provide the best illustration of the principals of the invention and its practical application , and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated . all such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly , legally , and equitably entitled .
a needle protecting device including : a sleeve - shaped base body which may be connected to a casing of the injection device or is formed by a casing of the injection device , a needle protecting sleeve which is mounted on the base body , wherein , in a proximal protective position , the needle protecting sleeve surrounds an injection needle of the injection device and , in a distal position , exposes the injection needle , a first block and a second block , one of which is connected non - sliding to the needle protecting sleeve and the other of which is connected non - sliding to the base body , wherein , in the protective position of the needle protecting sleeve , a blocking mesh is formed by the blocks pushing axially against each other and so preventing the needle protecting sleeve from sliding into the distal position , and a safety - release for releasing the blocking mesh , wherein the first block is formed by an elastically bendable latch which is connected rigidly to one of the needle protecting sleeve and the base body ; and the blocking mesh of the blocks is released by bending the latch against a restoring force generated in the latch .