Abstract:
An apparatus for administering a substance, including a housing, a piston, a container and a propelling device, the propelling device including a base element, a first shifting stage shiftable relative to the base element, and a second shifting stage shiftable relative to the base element and to the first shifting stage and slaving the first shifting stage, wherein the propelling device, container and piston are operably coupled to the housing and the first shifting stage is in contact with the piston.

Description:
BACKGROUND 
   The invention relates to a propelling device a piston in a container containing a liquid medicament. 
   SUMMARY 
   For administering medicaments in fluid form, more particularly in liquid form, for example insulin, portable injection and/or infusion devices find application. The liquid medicament is dispensed and administered finely metered from a fluid container by means of a piston. These devices find wide application as pumping devices and manually-actuated pens in insulin treatment. An injection pen is known, for example, from WO 93/16740. One example of such a portable infusion device is the H-TRON® plus insulin pump made by Disetronic Medical Systems AG. The user normally carries the device about with him all the time, for example at work or when on vacation. To ensure best possible freedom from an external supply, on the one hand, and freedom of movement, on the other, the device is designed to accommodate as much liquid medicament as possible without being bulky. This requirement for a compact design also exists basically in the medical field; thus also as regards stationary devices and systems. 
   The object of the invention is to provide a propelling device for a piston in a container containing a liquid medicament which is compact and thus particularly suited as the propelling device for a portable medicament administering device. 
   This object is achieved by the subject matter of claim  1 . 
   Just like known propelling devices, for example, the H-TRON® plus pump made by Disetronic Medical Systems AG known from EP 0143895 or the injection pen known from WO 93/16740, the propelling device in accordance with the present invention comprises a shifting stage shiftably mounted in or on a base element which, on shifting, advances a piston in a container containing a liquid medicament and thereby medicament from the container. Metering the amount of fluid to be dispensed occurs by setting the path length of the advance movement of the piston at the shifting stage. 
   In addition to the first shifting stage, at least a second shifting stage is provided which is shiftable in the advance direction of the piston relative to the base element and also relative to the first shifting stage, either manually or motor-driven, and carries the first shifting stage along when shifted in the advance direction of the piston. Due to the multistage operation of the propelling device, the maximum path length by which the piston can be advanced is split up into several increments, namely one increment per shifting stage. The at least two shifting stages are arranged overlapping at least in part in their starting positions. By splitting up the maximum shifting path length into several increments by cascading the propelling device, the overall length of the fluid container and the propelling device, as measured in the advance direction of the piston, is reduced. The shifting stages form preferably a telescopic drive. 
   Telescopic drives are known from WO 94/15660 and WO 97/00091 which are inserted in a medicament container open at the back end, and are secured to the container, whereby a drive spindle is power-rotated. Two shifting stages, each surrounding the drive spindle, run on and co-axially to the drive spindle. The outer one of these two shifting stages is prevented from rotating, in the case of WO 97/00091, with the aid of an anti-rotation lock to be extended with the outer shifting stage. By rotating the drive spindle, the middle shifting stage running thereon and the outer, non-rotatable shifting stage running on the middle shifting stage are advanced in the container to a container orifice. The piston for dispelling the liquid medicament is secured to the front end of the outer shifting stage. 
   In accordance with the invention, no fixed connection exists between the container, including piston, and the propelling device, instead the propelling device and the container, including piston, are each separately accommodated in a common housing so that either the container with the piston contained therein or the propelling device or both can be simply exchanged, since a connection of the propelling device to the piston and/or to the container does not first of all have to be released. This facilitates in particular replacing the container, for example, after all its contents have been administered. The propelling device can remain in the housing since it is not involved. 
   Preferably the propelling device too, is accommodated in the housing for being replaced new. The housing can directly form the cited base element. In a likewise preferred embodiment, the base element forms with the shifting stages accommodated therein and a motor drive, preferably mounted therein, an easily replaceable drive module secured in the housing. The first shifting stage of the propelling device comprises with the piston merely one contacting connection, i.e. it loosely contacts the piston or comes into contact with it only to advance it. The physical separation also renders it, in principle, possible to use the same propelling device for various forms of containers and also in conjunction with various types of pistons. 
   The shifting stages involved are preferably rigid components, linearly shiftable along one spatial axis only, although, of course, it is just as possible to employ flexible stages to approximate the fluid container. 
   How the several shifting stages are disposed with respect to each other is dictated by the individual application. Thus, in an arrangement corresponding to one preferred exemplary embodiment, the shifting stages disposed shiftable with respect to the base element are arranged so that their sliding axis, which are simultaneously the longitudinal axes, are in alignment. In its starting position, the one shifting stage thus surrounds the other like a sleeve. Arranging the shifting stages nested also has the advantage of a minimum extension transverse to the advance direction, this being used to advantage in both injection pens and in pumping devices. 
   If room is available alongside the fluid container, as is the case for example in the H-TRON® plus pump, as already cited, at least one shifting stage may be advantageously arranged there. While the axis, along which the one shifting stage is shifted in the direction of advancement of the piston, is located in the extension of the piston advance direction, the shifting axis of the other shifting stage is distanced parallel thereto. 
   The shifting stages are shifted preferably by spindle drives with respect to the base element and also relative to each other. Mating of the spindle drive threads is preferably arranged as near as possible to the piston. As a separate spindle drive is used for shifting each shifting stage with respect to the other and, finally, with respect to the base element, a rotational movement initiated, manually or powered, in the propelling device at a point is translated into a continually cumulative shifting movement. Using spindle drives permits one to precisely set the shifting distance. In addition, a spindle drive is also able to carry out the function of a mounting fixture between the individual shifting stages. 
   In accordance with one example embodiment, one of the two shifting stages is fixedly connected to a rotary drive. The two spindle drives, connected in series, comprise opposing threads. The total distance traveled per rotation of the rotary-driven shifting stage then always equals the sum of the shifting distances traveled by both shifting stages thus coupled. Thus, when thread pitches are the same, for example, a shifting travel is achieved which corresponds to twice the thread pitch of each individual shifting stage. 
   In accordance with another embodiment of the invention, the threads of two spindle drives connected in series have the same hand. The one shifting stage is advanced by the spindle drive member which rotary drives it or is carried along in the rotational movement. As far as it is shifted, it simply slaves the next shifting stage in its movement. As far as being simply slaved in rotation by the spindle drive member, its own rotational movement generates a forced shifting movement of the subsequent shifting stage prevented from being slaved into rotation by the an anti-rotation lock. This kind of spindle drive cascading permits a particularly precise setting of the shifting travel of the propelling device. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Although the invention primarily finds application in portable infusion and/or injection devices it may also be used to advantage in stationary systems. 
     The invention will now be explained by way of preferred embodiments with reference to the drawings in which: 
       FIG. 1  is a plan view of a first example embodiment of a propelling device in accordance with the invention, 
       FIG. 2  is a longitudinal section C—C taken through  FIG. 1 , 
       FIG. 3  is a longitudinal section D—D taken through  FIG. 1 , 
       FIG. 4  is the longitudinal section as shown in  FIG. 2 , but with the propelling device in its fully extended position, 
       FIG. 5  is the longitudinal section as shown in  FIG. 3 , but with the propelling device in its fully extended position, 
       FIG. 6  is an overall view in perspective of the propelling device as shown in  FIGS. 1–5   FIG. 7  is an illustration of the drive sleeve of the propelling device as shown in  FIGS. 1 to 6 , 
       FIG. 8  is an illustration of the feed nut of the propelling device as shown in  FIGS. 1 to 6 , 
       FIG. 9  is an illustration of the feed screw of the propelling device as shown in  FIGS. 1 to 6 , 
       FIG. 10  is an illustration of the anti-rotation lock of the propelling device as shown in  FIGS. 1 to 6 , 
       FIG. 11  is a longitudinal section through a second example embodiment of a propelling device in accordance with the invention, 
       FIG. 12  is another longitudinal section through the propelling device as shown in  FIG. 11 , 
       FIG. 13  is a longitudinal section through a third example embodiment of a propelling device in accordance with the invention, 
       FIG. 14  is another longitudinal section through the propelling device as shown in  FIG. 13 , 
       FIG. 15  is a longitudinal section through a fourth example embodiment of a propelling device in accordance with the invention, 
       FIG. 16  is another longitudinal section through the propelling device as shown in  FIG. 15 , 
       FIG. 17  is a longitudinal section through a fifth example embodiment of a propelling device in accordance with the invention, 
       FIG. 18  is another longitudinal section through the propelling device as shown in  FIG. 17 , 
       FIG. 19  is a plan view of a sixth example embodiment of a propelling device in accordance with the invention, 
       FIG. 20  is a longitudinal section D—D taken through the propelling device as shown in  FIG. 19 , 
       FIG. 21  is a longitudinal section E—E taken through the propelling device as shown in  FIG. 19 , 
       FIG. 22  is an overall view in perspective of the propelling device as shown in the  FIGS. 19 to 22 , 
       FIG. 23  is an illustration of an injection device including a propelling device in accordance with the invention 
       FIG. 24  is an illustration of an infusion device including a propelling device in accordance with the invention 
       FIG. 25  is an illustration of a seventh example embodiment of a propelling device in accordance with the invention, and 
       FIG. 26  is an illustration of the anti-rotation lock of the propelling device as shown in  FIG. 25 . 
   

   DETAILED DESCRIPTION 
   In the plan view of a propelling de shown in  FIG. 1 , the locations of the longitudinal sections illustrated in  FIGS. 2 and 3  are marked. 
   As its main components, the propelling device comprises a base element  1 , two shifting stages  10  and  20 , linearly shiftable with respect to the base element  1 , an axially fixed rotary drive member  30 , rotationally mounted in the base element  1 , and a motor  4 , rotationally driving the rotary drive member  30 . The first shifting stage  10  is configured as a threaded rod with a male thread  15 . The second shifting stage  20  is a threaded sleeve having a female thread  25  and a male thread  26 . The rotary drive member  30  is likewise cylindrically tubular and will be termed drive sleeve in the following, it comprising a female thread  36  in a head portion and a slaving gearwheel  22  in a footing portion. 
   The slaving gearwheel  33  meshes with a gearwheel  5  located on the shaft of the motor  4 . The threaded rod  10  and the threaded sleeve  20  form by their threads  15  and  25  a first spindle drive. The threaded sleeve  20  and the drive sleeve  30  form by their threads  26  and  36  a second spindle drive. The two sleeves  20  and  30  surround the threaded rod  10  concentrically about a common longitudinal centerline simultaneously pointing in the advance direction of the propelling device. In this advance direction, the propelling device, in itself being advanced, advances a piston accommodated in a reservoir or container containing a liquid medicament, for example in the form of a prefabricated syringe body, by the threaded rod  10 , as the most proximal or first shifting stage advancing the piston by means of a proximal flange  11  urging the piston in the direction of the orifice of the container to thus dispel fluid from the container. In this arrangement, the base element  1  locates the propelling device with respect to the container. The base element  1  may be secured to a frame or in a housing, or itself form the frame or housing. 
   In the base element  1 , the drive sleeve  30  is rotatively mounted, as well as located axially and radially, in a bearing position  3   a , preferably a plain bearing for rotation about the longitudinal centerline of the propelling device, simultaneously forming the axis of rotation thereof. A radial bearing position  3   b  for the drive sleeve  30  is located in the upper portion of the base element  1 . The threaded sleeve  20  is supported in the drive sleeve  30  by the second spindle drive formed between the threads  26  and  36 , i.e. the threaded sleeve  20  is shiftable via the second spindle drive with respect to the drive sleeve  30  and is also freely rotatable in the second spindle drive. 
   The threaded rod  10  is prevented from rotating with respect to the base element  1 . This anti-rotation lock is achieved by means of an anti-rotation fork  40 , which is linearly shiftable with respect to the threaded rod  10 , but is not rotatable and which itself is locked against rotating in the base element  1 , and is slidingly guided along the longitudinal centerline of the propelling device. 
   Advancement of the threaded rod  10  thus occurs as follows: 
   The rotative movement of the motor is transmitted via the spur reduction gearing  5 ,  33  to the drive sleeve  30 . The rotative movement of the drive sleeve  30  is transmitted via the second spindle drive formed between the threads  36  and  26  to the threaded sleeve  20 . Depending on the frictional forces acting on the threaded sleeve  20 , the threaded sleeve  20  is either slaved in the rotative movement or advanced along its axis of rotation by the spindle drive comprising the threads  26 ,  36 . The movement of the threaded sleeve  20  may also be a compounded telescoping/rotative movement. When only shifting of the threaded sleeve  20  is involved, it simply slaves the threaded rod  10  in this movement. When compounded slave rotation of the threaded sleeve  20  is involved, the rotative movement of the threaded sleeve  20  produces via the second spindle drive formed by the threads  15  and  25  an advance movement of the threaded rod  10  with respect to the threaded sleeve  20  due to the anti-rotation lock of the threaded rod  10 . To achieve this movement characteristic, the threads  26  and  15 , i.e. the threads via which each of the two shifting stages  10  and  20  are driven have the same hand. 
   Referring now to  FIGS. 2 and 3 , the propelling device is illustrated in a position in which it is partly extended from a starting position in the base element  1 . In the starting position, the two nested shifting stages  10  and  20  are accommodated in a cavity of the base element  1 . In this starting position, each of the two shifting stages  10  and  20  is in contact with the bottom of the cavity by its rear face contacting a bottoming surface area  2 . 
   Referring now to  FIGS. 4 and 5 , illustrated is the propelling device in the same sections as shown in  FIGS. 2 and 3 , but here in the fully extended position. In this position, the propelling device is also illustrated in an overall view in perspective in  FIG. 6 . 
   The proximal end position of the threaded rod  10  in the threaded sleeve  20  is dictated by a pair of stops  17 ,  27  and the most proximal end position of the threaded sleeve  20  in the drive sleeve  30  is dictated by a pair of stops  28 ,  38  ( FIG. 5 ). Each of the stops  27  and  38  is formed as a circumferential shoulder protruding radially inwards from the inner circumferential surface areas of the nut/sleeve  20  and  30  respectively, whilst the corresponding counter-stops  17  and  27  are formed by thickened annular portions of the threaded rod  10  and threaded sleeve  20  respectively. 
   A third pair of stops  8 ,  44  prevents the anti-rotation fork  40  from dropping out of the propelling device. The fork  40  may also be fixed to the threaded sleeve  20 . The stop  8  is formed by shoulders  7  protruding inwards in the direction of the shifting axis at the proximal end of the cavity of the base element  1 . The anti-rotation fork  40  comprises at its distal end corresponding, counterhook-type protuberances  44 , jutting radially outwards. 
   Referring now to  FIG. 7 , it illustrates a longitudinal section of the drive sleeve  30 . This essentially comprises a simple cylindrically-tubular base body  31 , configured thickened in the footing portion  32  in order for better guidance of the drive sleeve  30 , so that the outer shell surface area of the footing portion  32  slides in the right cylindrical cavity of the base element  1  on rotation of the drive sleeve  30 , and represents an additional means of radially stabilizing the system with respect to the bearing  3 . The slaving gearwheel  33  is a simple spur gear formed by a gear shoulder radially surrounding the shell surface area of the drive sleeve  30 . At its proximal end, the drive sleeve  30  is provided within a shoulder portion  34  protruding radially inwards with a thread  36 , which may be a fine thread, a multiple coarse pitch thread or even a regulating thread. The face  38  of the shoulder portion  34 , facing the footing portion  32 , forms the stop for the threaded sleeve  20 . 
   Referring now to  FIG. 8 , illustrated is the threaded sleeve  20  which likewise essentially comprises a simple cylindrically-tubular base body  21 . Starting from the most proximal end of the base body  21 , the threaded sleeve  20  is provided over by far the majority of its length with a thread  26  which runs in the thread  36  of the drive sleeve  30 . The distal portion  22  of the threaded sleeve  20  is a simple annular cylinder, the outer diameter of which is somewhat larger than the outer diameter of the portion having the thread  26 . Due to this thickening, the counter-stop  28  is formed for the stop  38  of the drive sleeve  30 . The footing portion  22  is slide-guided in the drive sleeve  30 , it featuring furthermore a circumferential recess at  23 , this recess  23  serving to seat a sealing ring. At the proximal end, the threaded sleeve  20  comprises a shoulder portion  24  protruding radially inwards. In the shoulder portion  24 , the thread  35  is configured (the same applying to it as what was said about thread  36 ). The face of the shoulder  24  facing the footing portion  22  serves as the stop  27  for the threaded rod  10 . 
     FIG. 9  illustrates the threaded rod  10 , likewise formed by a right cylindrical base body. A simple right cylindrical footing portion  12  is itself slightly thickened with respect to the substantially longer threaded portion, the footing portion  12  also serving as a sliding guide in shifting the threaded rod  10  in the threaded sleeve  20 . Seated in a circumferential annular container  13  in the footing portion  12  is a sealing ring in the fitted condition. The portion with the thread  15  has two opposing flats  14 . At its proximal end, the threaded rod  10  is faced with a blind hole  16  to which the flange  11  is bolted. In cooperation with the anti-rotation fork  40 , the flat  34  prevents the threaded rod  10  rotating with respect to the base element  1 . 
     FIG. 10  shows finally the anti-rotation fork  40 . It is a sleeve open at one end and closed off at the other end by a disk  41 , the sleeve being provided with slots over its entire length, two slots being evident in the example embodiment, owing to which or to the strip-shaped longitudinal receiving portions it has the form of two-pronged fork. The disk  41  is provided with a port  42  which is penetrated by the threaded rod  10  in the fitted condition. This port  42  is defined by two circumferential flats joined by the annular cylinder surface areas. The threaded rod  10  is thus axially slide-guided in the region of its thread  15  and of its two guide flats  14  in the port  42  but is prevented from rotating relative thereto by the anti-rotation fork  40 . The two axial projections  43  are snugly slide-guided in the base element  1  so that the anti-rotation fork  40  is itself unable to rotate with respect to the base element  1 , it instead merely permitted a longitudinal sliding action. It is in this way that rotation of the threaded rod  10  with respect to the base element  1  is prevented. As already mentioned, counterhook-shaped projections  44  at the distal end of the anti-rotation fork  40  prevent the anti-rotation fork  40  from dropping out of the base element  1 . 
   Referring now to  FIGS. 11 to 18 , shown are four alternative example embodiments of propelling devices in accordance with the invention. In these examples too, as in the first example embodiment, the straight lines, along which the shifting stages  10  and  20  are telescoped, are in alignment.  FIGS. 19 to 22  show a sixth example embodiment in which the first and the second shifting stages are shifted on straight lines distances parallel to each other. In the following, components comparable to those of the first example embodiment are assigned the same reference numerals since they fulfill the same function as those of the former. Reference is always made to the detailed explanations of the first example embodiment in supplementing the following description. 
   Unlike in the first example embodiment, in the following example embodiments to be described no free rotation of a shifting stage is permitted. 
   Each rotational movement introduced by a shifting stage is inevitably translated into a corresponding shifting movement of this shifting stage. 
   In the example embodiment of  FIGS. 11 and 12 , the rotational movement of the motor  4  is transmitted via the rim gear  5 ,  33  directly to the threaded sleeve  20 , “direct” in this context meaning that rotation of the slaving gearwheel  33  with respect to the threaded sleeve  20  is not possible. The threaded sleeve  20  is shifted closely slide-guided in a longitudinal direction in the slaving gearwheel  33  non-rotationally. In this example embodiment, the threaded rod  10  is formed cylindrically-tubular with a circumferential male thread  15  and an inner circumferential surface area in which an anti-rotation lock  40  is slide-guided. Via their threads, the threaded rod  10  and the threaded sleeve  20  form—as in the first example embodiment—a first spindle drive. The second spindle drive is formed by the threaded sleeve  20  and the base element  1 , said base element being provided with a thread  36  in a proximal shoulder portion  6  protruding radially inwards in the direction of the threaded sleeve  20 . Via the threads  26  and  36 , the threaded sleeve  20  and the shoulder portion  6  of the base element  1  form the second spindle drive. As viewed cross-sectionally, the threaded sleeve  20  forms a circular ring with two outer flats for the longitudinal guidance, and the thread  26  on the two circular segment sides for the rotary drive by the slaving gearwheel  33 . 
   In the example embodiment as shown in  FIGS. 11 and 12 , the anti-rotation lock  40  is guided in the inner cavity of the threaded rod  10  and prevents its rotation with respect to the base element. The anti-rotation lock  40  comprises a footing portion  43  which is slide-guided in the base element locked against rotating. Protruding from the footing portion  43  is a guide rod  42  which totally passes through the threaded rod  10  in the starting position of the propelling device. The guide rod  42  is formed so that it prevents rotation of the first shifting stage  10  with respect to the base element whilst permitting shifting. The second shifting stage  20  is seated on the footing portion  43  of the anti-rotation lock  40 , connected thereto so that it is freely rotational with respect to the footing portion  43 , on the one hand, but slaving the anti-rotation lock  40  in its own shifting movement, on the other, thus including the first shifting stage  10  in the shifting movement. 
   The rotation of the threaded sleeve  20  slaved by the slaving gearwheel  33  results in the threaded sleeve  20  being shifted by means of the second spindle drive in the advance direction V or in the opposite direction, the base element  1  acting as the direct reaction member of the second spindle drive, i.e. the threaded sleeve  20  is simultaneously the drive member and driven member of the second spindle drive. It is furthermore also the drive member of the first spindle drive, the driven member of which is the threaded sleeve  10 . The thread  26  leading to shifting of the threaded sleeve  20  and the corresponding thread  15  of the threaded sleeve  10  have the opposite hand. Every rotational movement of the threaded sleeve  20  always produces shifting of the threaded sleeve  10  due to a relative rotation. 
     FIGS. 13 and 14  illustrate a propelling device which functions comparable to that as shown in  FIGS. 11 and 12 . As regards the matching features, reference is made more particularly to the latter, but always supplementary to the explanations of the first example embodiment. 
   The propelling device as shown in  FIGS. 13 and 14  comprises likewise two spindle drives. However, in this example embodiment, the first shifting stage  10  nests the second shifting stage  20  although still termed a feed screw. The first spindle drive is formed by a female thread  15  of the threaded rod  10  and a corresponding male thread of the threaded sleeve  20 . An anti-rotation lock  40  prevents rotation of the threaded rod  10  with respect to the base element  1 . The anti-rotation lock  40  is comparable to the anti-rotation fork of the first example embodiment. The rotary drive of the threaded sleeve  20  is achieved by means of an axially fixed drive sleeve  30 , rotationally mounted in the base element  1 . In its footing portion, this drive sleeve  30  is rigidly connected to a slaving gearwheel which meshes with a gearwheel on the shaft of the motor  4 . The threaded sleeve  20  is prevented from rotating in the drive sleeve  30 , resulting in a transfer of the rotational movement from the drive sleeve  30  to the threaded sleeve  20  while permitting longitudinal slide-guided shifting. The drive sleeve  30  is furthermore centrally penetrated by a feed screw  6 . The feed screw  6  is rigidly connected to the base element  1 . In this way, the rotational movement of the drive sleeve  30  is translated into a rotational movement of the threaded sleeve  20  and by means of the feed screw  6  into a shifting movement of the threaded sleeve  20 . 
   Referring now to  FIGS. 15 and 16 , illustrated is a further propelling device in which, however, the threaded rod  10  is directly driven in rotation and the threaded sleeve  20  is prevented from any rotation with respect to the base element  1 . The rotary drive of the drive sleeve  30  occurs like in the example shown in  FIGS. 13 and 14 , except that within the drive sleeve  30  a rod-shaped rotary drive member  50  is provided non-rotationally connected thereto for the first threaded rod  10 . This rotary drive/slaving rod  50  protrudes from a cover secured to the distal face end of the drive sleeve  30  in the advance direction and into the threaded rod  10 . The rotary drive rod  50  is configured itself multi-stage, i.e. in the example embodiment two-stage corresponding to the number of movable shifting stages—like a telescope—following extension of the threaded rod  10 . The threaded sleeve  20  is prevented from rotating with respect to the base element  1  by an anti-rotation lock  40   a  provided as sliding surface area directly on the base element  1 . This is why any rotation of the drive sleeve  30  is always translated into a shifting movement of the threaded sleeve  20 . Due to the non-rotational connection, any rotation of the drive sleeve  30  results in the same rotation of the rotary drive rod  50  and thus of the threaded sleeve  10 . 
   The example embodiment shown in  FIGS. 17 and 18  substantially corresponds to that as of  FIGS. 15 and 16 , the differences in design being already apparent from  FIGS. 17 and 18 . 
     FIGS. 19 to 22  illustrate a sixth example embodiment. In this example embodiment, the first and second shifting stages are moved along two straight lines parallel to each other, i.e. the shifting axles of the first and the second spindle drives are spaced away parallel to each other. Included in the plan view in  FIG. 19  are the locations of the two longitudinal sections shown in  FIGS. 20 and 21 . 
   Also in this sixth example embodiment, components having the same functions as those of previous example embodiments are given the same reference numerals. 
   Advancement of the most-proximal first shifting stage  10  is again achieved by a rotary drive of a drive stage  30  which in this example embodiment is devised as a simple spindle. The spindle  30  is rotationally mounted in the base element  1 , but prevented from any other movement with respect to the base element  1 . The axis of rotation of the spindle  30  runs in the advance direction V 1  and V 2  of the shifting stages  10  and  20 . The spindle  30  is itself rotary driven by a motor  4  via spur gears  5 ,  33 . Seated on the spindle  30  is a first sleeve body  20   a  of the second shifting stage  20 . The second shifting stage  20  is U-shaped. The sleeve body  20   a  forms one leg of the U and a second sleeve body  20   b , spaced away from the other parallel thereto, forms the other leg of the U. The two sleeve bodies  20   a  and  20   b  protrude perpendicularly from a connecting web  20   c , said sleeve bodies forming therewith as the cover a housing of the second shifting stage  20 . In the base element  1 , the sleeve body  20   a  and the connecting web  20   c  are movably slide-guided along the axis of rotation of the spindle  30 , and prevented from rotating. In the second sleeve body  20   b , the first shifting stage  10 , again configured as a feed screw, is shifted in and contrary to the advance direction of the piston and shiftingly rotated around, the longitudinal centerline of the second sleeve body  20   b  which coincides with its own longitudinal centerline. 
   Rotation of the spindle  30  causes the second shifting stage  20  to be forcibily shifted along the axis of rotation of the spindle via the pairing of the threads  26 ,  36 . Seated on the spindle  30 , non-rotationally with respect to the spindle  30  but axially shiftable, is a spur gear  38   a . Slide-guiding and non-rotational shifting is formed by flats on the circumference of the spindle  30  and corresponding companion flats on the spur gear  38   a . The spur gear  38   a  is accommodated in the housing  20   a–c  of the second shifting stage  20  so that it is slaved in the shifting movement of the latter while being freely rotational with respect to the housing of the shifting stage  20 . Rotationally mounted in the housing of the shifting stage  20  are, furthermore, a second gearwheel  38   b  meshing with the spur gear  38   a  as well as a third spur gear  38   c  meshing with the spur gear  38   b . The three gearwheels  38   a ,  38   b  and  38   c  form a spur gear unit for rotary drive of a slaving rod  50 , protruding perpendicularly from the gearwheel  38   c , for the threaded rod  10 . The slaving rod  50  protrudes into the cylindrically-tubular threaded rod  10  and is non-rotationally slide-guided. It slaves the threaded rod  10  in its own rotation compulsorily and with zero clearance. Like in the aforementioned example embodiments, rotation of the threaded rod  10  is translated into a shifting movement of the threaded rod  10  by means of a first spindle drive formed by the pairing of the threads  15 ,  25 . 
     FIG. 23  shows a so-called pen as used in particular for insulin injection. Accommodated in the housing G of the injection pen is a syringe body A comprising a piston K and containing a liquid medicament. The piston is shiftable in the direction of a syringe body orifice in an advance direction V, dispelling on its advancement a precisely metered amount of fluid from the syringe body A via a needle hub into and through a needle N. The piston K is held in the syringe body A, i.e. it is removed together with the syringe body A and may be replaced by a new syringe body with a new piston. The base element  1  serves, together with a dispensing and actuator knob  4 , to mount the propelling device, is accommodated independent of the container A in the housing G, and is fixed in its position relative to the container A and the piston K. However, with its proximal edge, the base element  1  serves to locate the syringe body A. Accordingly, screwing open the housing G results in a proximal and a distal housing sleeve, the syringe body A being accommodated in the proximal housing half and the propelling device in the distal housing half. When screwed together, the base element  1  is forced against the distal edge of the syringe body so as to seat the syringe body A non-shiftable in a longitudinal direction in the housing G. 
   Advancement of the piston K is caused by extension of a threaded rod  10  which, on being extended, urges against the distal end of the piston to advance the piston K in the syringe body A. The threaded rod  10  forms the first shifting stage of a telescopic drive. The second shifting stage is formed by a threaded sleeve  20  in which the threaded rod  10  runs by means of a first spindle drive. The threaded sleeve  20  is itself nested in a drive sleeve  30  with which it forms a second spindle drive for extending and retracting it in and against the advance direction V. The drive sleeve  30  is rotationally mounted in the housing  1 . The drive sleeve  30  is manually turned with respect to the housing G by means of the dispensing and actuator knob  4  around the longitudinal centerline of the propelling device  10 ,  20 ,  30 , pointing in the advance direction V, for setting the dose of insulin to be administered, and is then advanced together with the threaded rod  10  and the threaded sleeve  20  along the longitudinal axis. After injection or after actuation of a reset knob, the feed nut is then returned into its starting position ready for the next injection, due to a spring F thereby being compressed. 
   Dispensing and manually actuating the injection pen occurs as in known pens, reference being made in this respect, for example, to the description of such an injection pen in WO 93/16740. However, contrary to known injection pens, a propelling device in accordance with the invention is used for the piston K of the pen as shown in  FIG. 23 . The propelling device of this example application corresponding the first example embodiment. 
     FIG. 24  illustrates a portable infusion device, more particularly for insulin treatment, including a motor-powered propelling device, for instance, the propelling device as shown in the  FIGS. 1 to 10 . The base element  1 —including the drive sleeve  30 , two shifting stages  10  and  20  and the anti-rotation fork  40 —is fixed in place in the pump housing G by, among other things, being mutually shaped accordingly. 
   To facilitate its replacement, the syringe body A including the piston K retained therein can be simply inserted in and removed from the housing G in the example as shown in  FIG. 23 . In other words, free of any connection first needing to be released. When replacing the syringe body A, the propelling device can remain in the housing G or be replaced independent of the syringe body A. However, as already discussed with reference to the example embodiment as shown in  FIG. 23 , the base element  1  serves as a stopper, i.e. for locating the syringe body A lengthwise. The syringe body A can be moved to and fro in an insertion shaft of the housing G until this stop, it thereby being guided lengthwise. After insertion, it is locked in place to prevent it from being advanced in the shaft by means of the locking means to be secured to the housing G. 
   In extending from the most distal position of the propelling device as shown in  FIG. 24 , the threaded rod  10  urges the piston K into the syringe body A in the direction V towards the syringe body orifice which in the example embodiment is, still at this time, sealed off tight by a diaphragm. The propelling device is powered by the motor  4  via a spur gear unit  5   a  to  5   f  as well as  33 . For further details as to the propelling device, reference is made particularly to the example embodiment as shown in  FIGS. 1 to 10 . However, instead of this, the other propelling devices as described above may be likewise employed. Thus, for example, the propelling device as shown in  FIGS. 19 to 22  could be ideally installed in the space available alongside the syringe body A and the stages of the propelling device.  FIGS. 25 and 26  illustrate a seventh example embodiment of the invention having a propelling device which is substantially the same as that of the first example embodiment.  FIG. 25  is an illustration of the propelling device in an overall view in perspective, in a view from above with the two entered sections A—A and B—B and parts of these two sections.  FIG. 26  is an illustration of an anti-rotation lock  40  in an overall view in perspective as viewed from the rear and in the two sections A—A and B—B as entered. Also evident from  FIG. 26  is a slaving element  41   a , applied to the anti-rotation lock  40 , which is a further development of the anti-rotation lock of the first example embodiment. 
   However, the anti-rotation lock  40  of the seventh example embodiment is not formed by an anti-rotation fork with penetratable linear guiding slots, instead the anti-rotation lock  40  surrounds the part of the propelling device extensible from the base element  1  with the exception of the extended part of the first shifting stage  10 . The anti-rotation lock  40  of the seventh example embodiment is configured as a closed sleeve body providing soilage protection, it preferably being made as a ceramic component. Instead of penetration slots, this sleeve body  43  comprises two groove-shaped recesses  43   a  oriented in the longitudinal direction of the sleeve body  43 , the linear guiding means of the base element  1  engaging each of these recesses for linear guidance of the anti-rotation lock  40 . This linear guidance as such is comparable to that of the first example embodiment. In this example embodiment, two linear recesses  43   a  are provided ending in the proximal circumferential edge of the sleeve body  43 . In principle, even a single recess would suffice, however, also more than two recesses  43   a  may be provided. 
   Inserted in the sleeve body  43  is a slaving element  41   a , screwed to the disk  41  forming the bottom of the sleeve. As best evident from  FIG. 26 , the slaving element  41   a  is a partly annular component, semi-circular in the example embodiment, the outer circumferential surface areas are partly in close contact with the inner circumferential surface area of the sleeve body  43  for the purpose of positioning the screw holes. The slaving element  41   a  forms a cuff for the second shifting stage  20  and serves to slave the anti-rotation lock  40  in the movement of the second shifting stage  20 . For this purpose, the slaving element  41   a  engages a circumferential recess in the outer shell surface area of the second shifting stage  2 ( i  by a flange  41   b  protruding radially inwards from an inner circumferential surface area. The anti-rotation lock  40  is locked from shifting in both the extending direction and the retraction direction at the second shifting stage  20  without, however, obstructing the rotational movement of the second shifting stage  20 .