Patent Publication Number: US-2023158240-A1

Title: Device for administering a fluid

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for administering a fluid, which device can be in the form of, for example, a self-filling syringe without a needle, with which a liquid drug can be administered to animals. 
     BACKGROUND OF THE INVENTION 
     Such devices for administering a fluid are intended to be as lightweight as possible, to have a long service life and to be associated with low maintenance costs and outlay. 
     It is the object of the invention to provide a device for administering a fluid that realizes at least one of the properties mentioned. 
     The invention is defined in claim  1 . Advantageous refinements are specified in the dependent claims. 
     SUMMARY OF THE INVENTION 
     The device according to the invention for administering a fluid comprises a cylinder which has an open dispensing end, a piston which is displaceable between a front and a rear end position in the cylinder and is connected to a piston rod that protrudes along a first direction beyond a rear end of the cylinder opposite the open dispensing end and is guided in a receiving block, a nonreturn valve (or intake valve) closing the open dispensing end, and a tensioning device which is connected to the piston rod and is arranged in the receiving block. The tensioning device can move the piston rod in a tensioning operation, when the piston is in its front end position, along the first direction until the piston is in its rear end position, in order thereby to fill the cylinder with the fluid to be administered and in order to pretension the piston rod toward the open dispensing end. Furthermore, the tensioning device, when the piston is in its rear end position, can release the piston rod in a dispensing operation, and therefore the piston moves counter to the first direction as far as its front end position because of the applied pretension and, in the process, the fluid in the cylinder is dispensed via the nonreturn valve for administering. 
     The administering device according to the invention furthermore has a ramp which is rotatable by means of the motor and has a ramp track extending along a helical line. The ramp track ascends from a first plateau or level along a region of inclination to a second plateau or second level and descends from the second plateau to the first plateau via a transition flank. The ramp track therefore has a single turn and may be referred to as being helical with a step. 
     The tensioning device furthermore comprises a roller which is in contact with the ramp track and is mounted rotatably in a driver, which is connected to that end of the piston rod which protrudes out of the cylinder, and therefore, upon rotation of the ramp, the ramp track runs below the roller, which thereby rotates. The roller is preferably mounted in such a manner that its axis of rotation is perpendicular to the first direction (or perpendicular to the longitudinal axis of the piston rod). 
     For the tensioning operation, the ramp track, starting from contact of the roller with the first plateau, can be rotated in such a manner that the roller runs on the region of inclination as far as the second plateau and the piston is thereby moved into its rear end position. For the dispensing operation, the ramp track, starting from a contact of the roller with the second plateau, can be rotated until the roller via the transition flank reaches the first plateau and the piston is thereby moved into its front end position. 
     The distance of the second plateau from the first plateau along the axis of rotation of the ramp preferably corresponds to the distance from the front to the rear end position of the piston along the first direction and therefore to the piston stroke. 
     The rotational movement of the motor is therefore converted by means of the ramp and the roller into a translatory movement of the piston rod along its longitudinal axis. The administering device can therefore be tensioned by means of the motor, and therefore a user merely has to actuate a triggering element, for example a pushbutton, a switch, a rocker switch or a button, in order to release the dispensing operation and therefore to administer the fluid. It is therefore possible, for example, for many animals to be rapidly injected one after another with medication. 
     In the case of the administering device according to the invention, the roller has a support region which rests on the region of inclination of the ramp track, and at least one laterally adjoining side region which has a smaller outside diameter than that of the support region and which does not rest on the region of inclination of the ramp track. During the dispensing operation, both the support region and the side region can come into contact with an edge of the ramp track, said edge connecting the second plateau to the transition flank. This leads to the advantage of there being a relatively low rolling or frictional resistance between the roller and the ramp track in the region of the region of inclination. During the transfer via the edge for the dispensing operation, both the receiving region and the side region then rest on the edge, and therefore the support surface is enlarged here, and thus a smaller pressure is present. This is advantageous since, during the transfer of the roller via the edge, the greatest force acts on the roller, and therefore undesirable pressure peaks can be reduced. The durability of the roller is therefore increased. 
     In particular, the roller on either side of the support region can have a laterally adjoining side region with a smaller outside diameter than that of the support region. This leads to a further reduction of the pressure on the roller during the transfer via the edge. 
     The roller can be designed in such a manner that the outside diameter of the support region is constant. The outside diameter of the respective side region can decrease in a direction toward the side of the roller (or in a direction away from the support region or as the distance from the support region becomes greater). 
     The roller can be in the form of a plastics roller. The ramp can be composed of metal. 
     The region of inclination of the ramp track can have a first portion adjoining the first plateau and an adjoining second portion, wherein the inclination of the second portion is greater than the inclination of the first portion. 
     The effect is therefore advantageously achieved that, at the beginning of the tensioning operation, the ramp track has a smaller inclination, as a result of which the motor has to apply less force or torque. This is advantageous during the starting of the motor since more current is used during the starting. As soon as the first portion merges into the second portion, said starting problem has been overcome, and therefore a greater inclination can easily be realized here. This increases the durability of the motor. 
     The region of inclination of the ramp track can be designed in such a manner that both portions are linear with respect to the angle of rotation of the screw. However, it is also possible for the first portion and/or the second portion to have a nonlinear profile with respect to the angle of rotation. In this case, the inclination of the respective portion is preferably the average inclination of the respective portion. The nonlinear profile of the respective portion is preferably a profile in which the local inclination increases as the angle of rotation increases. The nonlinear profile of the respective portion can preferably be a concave curvature profile. 
     In particular, the rotational angle region (or the length of the angle of rotation) of the first portion can be smaller than the rotational angle region (or the length of the angle of rotation) of the second portion. The ratio of the rotational angle region of the first portion to the rotational angle region of the second portion is preferably no more than 4/6 and not less than 1/9. 
     The cylinder together with the nonreturn valve can be in the form of an exchangeable front assembly, which may also be referred to as an exchangeable assembly, which is releasably connected to the receiving block. 
     The entire front assembly which is subject to the greatest amount of wear during the operation of the device for administering a fluid (preferably a liquid) can then be changed into a new (preferably structurally identical) front assembly which is then connected to the receiving block. The durability of the entire device for administering a fluid is therefore significantly increased. 
     The exchangeable assembly can be arranged at the front end of the device according to the invention. In particular, for example, during correct use of the device according to the invention part of the exchangeable assembly can be in contact with the animal to which the fluid is intended to be administered. In this respect, at least this part of the exchangeable assembly protrudes from the rest of the device according to the invention. The exchangeable assembly can have a part which forms the distal end of the device according to the invention, and therefore, for example, for this reason the exchangeable assembly may also be referred to as an exchangeable front assembly. 
     An exchangeable front assembly is understood here as meaning in particular that the front assembly as a whole can be separated from the receiving block and replaced by a structurally identical front assembly which is connected for exchange to the receiving block. However, it is also possible for the front assembly which is separated from the receiving block to be maintained (by, for example, worn parts, such as seals, being exchanged) and then being connected again to the receiving block. 
     Since the front assembly is completely separated from the receiving block and is then maintained or exchanged, undesirable contaminations can be reliably avoided. This is significantly more difficult and associated with higher costs if, for example, only the firstly wearing O-ring seals in the front assembly are exchanged individually when the front assembly, as previously customary, is installed in such a manner that it cannot be separated from the rest of the administering device without being destroyed. 
     The releasable connection between the front assembly and the receiving block can be in particular, a screw connection. However, any other type of releasable connection, such as, for example, a bayonet connection, is also possible. 
     The administering device according to the invention can have a nozzle for administering the fluid without a needle, said nozzle being connected via the nonreturn valve to the open dispensing end of the cylinder and being part of the front assembly. It is therefore possible for the nozzle also to be exchanged at the same time as the front assembly is exchanged. 
     Alternatively, the device can have a needle or canula which is connected via the nonreturn valve to the open dispensing end of the cylinder and is part of the front assembly. The needle and the canula may for their part be exchangeable. 
     The administering device according to the invention can have precisely one cylinder with precisely one piston rod and precisely one front assembly. However, it is also possible for the administering device to have two or more cylinders with two or more piston rods and two or more front assemblies that are all designed identically, and therefore two or more identical or different fluids can be admitted simultaneously. The individual cylinders can have identical or different volume. 
     The administering device according to the invention is in particular in the form of a self-filling administering device which uses the tensioning operation to enable the cylinder to be filled with the fluid to be administered (for example a liquid to be administered). 
     This can be realized, for example, in such a manner that filling of the cylinder already takes place during the entire tensioning operation. Alternatively, the administering device can be designed in such a manner that, during the tensioning operation, a negative pressure is built up in the cylinder, said negative pressure then being used, when the piston is in its rear end position, for the fluid to be sucked into the cylinder because of the negative pressure. For this purpose, for example, the distal end of the piston can have a blind hole which extends in the longitudinal direction of the piston rod and from which one or more radial bores branch off, the radial bores, in the rear end position of the piston, producing a fluid connection to a reservoir of the fluid to be administered. 
     The administering device according to the invention can have the motor which is used for carrying out the tensioning operation. It may also be stated that the motor provides the energy necessary for building up the pretensioning of the piston rod. The motor can be mounted, in particular on the receiving block. 
     In order to operate the motor and possible further consumers, the energy source provided can be, for example, a battery and/or a storage battery. The energy source can be formed, for example, in the base or as the base of the administering device. Furthermore, the energy source can be exchangeable or fixedly installed. 
     The tensioning device can have a spring which pretensions the piston rod toward the open dispensing end when the piston is in the rear end position. 
     In the case of the administering device according to the invention, the receiving block can be in the form of an integral receiving block which is produced by an additive production method. 
     Such an additive production method may also be referred to as  3 D printing and may be, for example, a laser sintering method. 
     This leads to the receiving block being able to be produced with a relatively low weight and high rigidity and strength. The overall weight of the administering device is therefore kept as low as possible, thus making the operation thereof for a user agreeable and durable. 
     Furthermore, the integral formation of the receiving block by means of the additive production method leads in an advantageous manner to it being possible for the receiving block to be formed extremely compactly, which is not possible with conventional machining production methods. 
     The material used for the receiving block is preferably a metal (or a metal alloy) and, in particular, titanium, and therefore the receiving block is composed of metal (or a metal alloy) and in particular of titanium. Furthermore, aluminum, steel (for example maraging steel), stainless steel, titanium, a nickel alloy and/or a cobalt chromium alloy can be used as material for the receiving block. Further possible materials are AlSiMg alloys, CoCrMo alloys and nickel chromium alloys. Furthermore, materials which are weldable can be used. All of these materials can be present in a form (for example as powder) in order to able to produce the receiving block from them by means of an additive production method (and in particular by means of the laser sintering). 
     The receiving block can have a motor bearing, a guide cylinder for the piston rod, at least one receptacle for a control board, a receptacle for a fluid connection for a fluid container and/or at least one housing fixing point, which is/are formed integrally with the receiving block. 
     The piston can be formed integrally with the piston rod. In this case, the front end of the piston rod forms the piston. However, it is also possible for the piston to be a separate element that is connected to the piston rod. 
     It goes without saying that the features mentioned above and those which have yet to be explained below are usable not only in the stated combinations, but also in other combinations or by themselves without departing from the scope of the present invention. 
     The invention will be explained in more detail below using exemplary embodiments with reference to the attached drawings which likewise disclose features essential to the invention. These exemplary embodiments serve merely for illustrative purposes and should be interpreted as restrictive. For example, a description of an exemplary embodiment with a multiplicity of elements or components should not be interpreted to the effect that all of said elements or components are necessary for implementation purposes. On the contrary, other exemplary embodiments may also contain alternative elements and components, fewer elements or components or additional elements or components. Elements or components of various exemplary embodiments may be combined with one another, unless stated otherwise. Modifications and alterations that are described for one of the exemplary embodiments may also be applied to other exemplary embodiments. In order to avoid repetitions, identical or mutually corresponding elements in the various figures are denoted by the same reference signs and will not be explained repeatedly. In the figures: 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    shows a perspective view of an exemplary embodiment of the administering device  1  according to the invention; 
         FIG.  2    shows a schematic sectional view of the administering device  1  from  FIG.  1   ; 
         FIG.  3    shows a schematic, enlarged sectional view of the first front assembly  13 ; 
         FIG.  4    shows a schematic sectional view of the first front assembly  13  and of the distal end  30  of the receiving block  10  in a state not connected to each other; 
         FIG.  5    shows a schematic sectional view of the first front assembly  13  screwed into the distal end of the receiving block  10 , with the piston  36  being in its rear end position; 
         FIG.  6    shows a sectional view according to  FIG.  5   , wherein the piston  36  is in its front end position and the triggering cage  21  is in its release position for the administering operation; 
         FIG.  7    shows a perspective illustration of the receiving block  10  together with the tensioning device S, wherein the tensioning device S is in the basic position in which the piston  36  is in its front end position; 
         FIG.  8    shows a perspective illustration of the receiving block  10  together with the tensioning device S according to  FIG.  7   , wherein the tensioning device S is in its tensioned position in which the piston  36  is in its rear end position; 
         FIG.  9    shows a sectional view of the receiving block  10  together with the tensioning device S according to  FIG.  8   ; 
         FIG.  10    shows a perspective enlarged detailed illustration of the rear part of the tensioning device S with the roller  51  and ramp  52  of a modification of the administering device  1  according to the invention with just one cylinder-piston arrangement; 
         FIG.  11 A  shows a diagram for illustrating the profile of the ramp track  53 , wherein the angle of rotation is plotted along the x axis and the stroke along the longitudinal axis of the piston rod  36  is plotted along the y axis, 
         FIG.  11 B  shows a diagram for illustrating the modified profile of the ramp track  53 , wherein the angle of rotation is plotted along the x axis and the stroke along the longitudinal axis of the piston rod  36  is plotted along the y axis, 
         FIG.  12    shows a perspective illustration of the roller  51 ; 
         FIG.  13    shows a top view of the roller  51 ; 
         FIGS.  14  and  15    show perspective illustrations of the receiving block  10 ; 
         FIG.  16    shows a top view of the receiving block  10 , and 
         FIG.  17    shows a sectional view of the receiving block  10 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the exemplary embodiment shown in  FIG.  1   , the device  1  according to the invention for administering a fluid (for example a liquid) comprises a housing  2  which comprises a base  3 , which can also be in the form of a standing base  3 , a gripping portion  4  for holding the device  1 , a trigger  5  which is arranged in the gripping portion  4  and is intended for actuating the device  1 , a head region  6  with a dispensing region  7 , and a receptacle  8  in the upper end of the head region  6 . 
     In the exemplary embodiment described here, the device  1  according to the invention, which may also be referred to as the administering device  1 , is designed for simultaneously administering two different drugs in animals, wherein the administration of the drug is carried out through the skin without needles. 
     In the case of the administering device  1  according to the invention, a separate cylinder-piston arrangement is provided for each medication, as will also be described in detail below, said cylinder-piston arrangement being in each case in the form of a type of self-filling device in such a manner that a movement of the piston toward the dispensing end causes the fluid to be injected and an opposite movement of the piston causes filling of the cylinder for the next injection operation. 
     As can be inferred from the schematic sectional illustration of the administering device  1  in  FIG.  2   , the administering device  1  comprises a receiving block  10  which bears a control board  11  and a motor  12 , and two front assemblies  13 ,  14 , of which only the front assembly  13  is visible in the illustration of  FIG.  2   . Since the front assemblies  13  and  14  are constructed identically, essentially only the front assembly  13  will be described in detail below. A medication container M containing a liquid drug for the front assembly  13  is shown schematically in the receptacle  8 . 
     A sectional illustration of the front assembly  13  is shown in  FIG.  3   . The front assembly  13  comprises an insert  15  in which a syringe cylinder  16  with an open dispensing end  17  is formed. A nonreturn valve  18  (or an intake valve  18 ) is arranged on the outlet side at the open dispensing end  17 . When the nonreturn valve  18  is opened, the open dispensing end  17  leads into a nozzle  18  via which the fluid to be dispensed (here the corresponding liquid drug) is dispensed. 
     The nonreturn valve  18  is pretensioned via a spring  20  toward the open dispensing end  17  and closes the open dispensing end  17  in the position of the nonreturn valve  18  that is shown in  FIG.  3   . 
     Furthermore, the front assembly  13  comprises a triggering cage  21  which extends over the nozzle  19 , is pressed by means of a spring  22  in the direction from the open dispensing end  17  toward the nozzle  19  and is pretensioned. The triggering cage  21  is mounted displaceably along the longitudinal axis of the front assembly  13  (from the left to the right in  FIG.  3   ), and therefore, when the administering device  1  is placed onto the corresponding skin site of the animal, said triggering cage is displaced in the direction from the nozzle  19  toward the open dispensing end  17  and, in the process, triggers, for example, a contact sensor (not shown) which enables the triggering of the administering operation, as will also be described in detail below. 
     The insert  15  has radially running supply channels  25  at a proximal end  24  of the syringe cylinder  16  lying opposite the open dispensing end  17 , via which supply channels the fluid to be administered or the liquid drug passes into the syringe cylinder  16  for a next injection operation. 
     An external thread  27  is formed, and a guide bushing  28  arranged, at the proximal end  26  of the front assembly  13 , and therefore the front assembly  13  can be screwed into a distal end  30  of the receiving block  10  ( FIG.  4   ) since an internal thread  31  for the external thread  27  of the front assembly  13  is provided in the distal end  30 .  FIG.  4    shows the front assembly  13  and the distal end  30  of the receiving block  10  prior to the screwing-in operation. In  FIG.  5   , the two elements  13 ,  30  are screwed to each other such that a piston rod  35  which is guided in the receiving block  10  slightly protrudes with a piston  36  formed at its distal end into the syringe cylinder  16 , and the piston rod  35  is guided through the guide bushing  28 . As will be described in detail below, the piston rod  35  can be moved from the basic position shown in  FIG.  5    in the direction toward the open dispensing end  17  to the injection or dispensing position shown in  FIG.  6    and from said position back again into the basic position shown in  FIG.  5   . 
     If the piston rod  35  is in the basic position, its distal end and therefore the piston  36  is in its rear end position ( FIG.  5   ). When the piston rod  35  is in the dispensing position, the piston  36  is in its front end position ( FIG.  6   ). 
     When the piston rod  35  is positioned in the basic position shown in  FIG.  5   , the syringe cylinder  16  is filled with the liquid drug to be injected. A movement of the piston rod  35  toward the open dispensing end  17  then leads to the nonreturn valve  18  opening and thus to the liquid being dispensed via the nozzle  19  as a jet which cuts into the skin of the animal to an extent such that the drug can be administered into the skin through said cut. 
     During the rearward movement from the dispensing position shown in  FIG.  6    to the basic position shown in  FIG.  5    (a movement along a first direction), the nonreturn valve  18  closes and a negative pressure is produced in the syringe cylinder  16 , said negative pressure being greater the further the piston rod  35  is moved away from the open dispensing end  17 . As soon as the piston rod  35  is brought into its basic position, there is a fluid connection between the syringe cylinder  16  and at least one of the supply channels  25 . In order to realize the fluid connection, an axial blind hole  37  is formed in the distal end of the piston  36  and at least one transverse bore  38  is formed which extends radially from the blind bore  37  and the end of which that faces away from the blind bore  37  leads into one of the supply channels  25 . Since the supply channels  25  for their part lead into a chamber  32  which is formed between the insert  15  and the distal end  30  of the receiving block  10  and is connected via a connection element  33  to the medication container M, only shown in  FIG.  2   , the liquid drug because of the negative pressure present in the syringe cylinder  16  is sucked out of the medication container M via the connection element  33 , the chamber  32 , the supply channel or supply channels  25 , the transverse bore(s)  38  and the blind bore  37  into the syringe cylinder  16  such that the latter is filled with the liquid drug. Therefore, the drug can be administered again during the next triggering operation, wherein, at the beginning of the movement of the piston rod  35  from the basic position to the injection position, some of the liquid drug is pressed back into the chamber  32  via the supply channels  25 . This pressing back is advantageous since the piston  36  or the piston rod  35  can thereby be accelerated more easily, which leads to a higher pressure with which the rest of the drug in the syringe cylinder  16  is acted upon and which is desirable for the described injection without a needle. 
     The front assembly  13  which in particular comprises the syringe cylinder  16 , the nonreturn valve  18  and the nozzle  19  is designed to be exchangeable as a whole. It can be screwed by means of its external thread  27  into, and unscrewed again from, the corresponding internal thread  31  which is formed at the distal end  30  of the receiving block  10 . Since the front assembly  13  is subject to wear during operation of the administering device  1 , a worn front assembly  13  can therefore be easily exchanged for a new, structurally identical front assembly  13 . This advantageously leads to the administering device  1  as a whole being able to be used for longer since the components of the administering device  1  that are most susceptible to wear can be easily exchanged. 
     Since the front assembly  13  can be completely exchanged, undesirable contaminations can be reliably avoided, which would be significantly more difficult to avoid and would be associated with higher costs if, for example, the firstly wearing O-ring seals in the administering devices known from the art were individually exchanged in the region of the cylinder which is connected fixedly and nonexchangeably to the rest of the device known from the art. 
     As can best be seen from  FIGS.  7  to  9   , the receiving block  10  has a first receiving cylinder  40 , into which the piston rod  35  for the first front assembly  13  is guided, and a second receiving cylinder  140 , in which a piston rod  135  for the second front assembly  14  is guided. Since the construction of the two cylinder-piston arrangements and therefore of the two receiving cylinders  40 ,  140  is identical, essentially only the first cylinder-piston arrangement with the first receiving cylinder  40  will be described below in the description of the receiving block  10 . Corresponding elements in the case of the second receiving cylinder  140  are denoted by reference signs which are greater by 100 than in the case of the elements of the first receiving cylinder  40  but will not be described once again. 
     The piston rod  35  runs through the first receiving cylinder  40  in which a spring  41  for moving the piston rod  35  from the tensioned basic position shown in  FIG.  5    to the injection position shown in  FIG.  6    is contained. A distal end  42  of the spring  41  lies against a stop portion  43  of the piston rod  35 . The proximal end  44  of the spring  41  lies against a guide bushing  45  which is screwed into the proximal end of the first receiving cylinder  40 , and therefore, during a movement of the piston rod from the injection position shown in  FIG.  6    along the first direction to the pretensioned basic position shown in  FIG.  5   , the spring  41  is compressed and is thereby pretensioned, as is illustrated in  FIG.  9   . 
     As can be gathered in particular from the enlarged perspective illustration in  FIG.  10   , that end of the piston rod  35  which protrudes proximally out of the receiving cylinder  40  is connected to a driver  50  which has a rotatably mounted roller  51 , wherein the axis of rotation of the roller  51  extends substantially perpendicularly to the longitudinal axis of the piston rod  35 . 
     The perspective illustration in  FIG.  10    shows a modification of the administering device  1  according to the invention. In this modification, only a single cylinder-piston arrangement is formed, and the driver  50  is connected to the proximal end of the piston rod  35  and to the proximal end of a guide rod  39 , which is mounted displaceably in the receiving block  10 . 
     The roller  51  runs on a ramp  52  which rotates under the roller  51  and is rotated by the motor  12  about an axis parallel to the longitudinal axis of the piston rod  35 . A battery and/or a storage battery which can be recharged is provided as current supply for the motor. The battery and/or the storage battery can be arranged, for example, in the base  3  or as the base  3  of the administering device  1 . 
     The ramp  52  has a ramp track  53  which runs with a single turn along a helical line, as can be gathered in particular from  FIGS.  7 ,  8  and  10   . 
     In  FIG.  11 A , the angle of rotation α is plotted in relation to the pitch difference z parallel to the longitudinal direction of the piston rod  35 , wherein the starting point is that, at the angle of rotation of α0=0°, the smallest pitch height z0 is present and the piston  36  is in its front end position. If the ramp  52  is then rotated, the ramp track  53  runs under the roller  51  and leads to the rotational movement of the ramp track  53  being converted into a translatory movement of the roller  51  together with the driver  50  and therefore the piston rod  35  along the longitudinal axis of the piston rod  35 , such that the piston rod  35  is moved from its injection position shown in  FIG.  6    into its basic position shown in  FIG.  5   . 
     For this purpose, the unwound ramp track  53  according to  FIG.  11 A  runs in such a manner that there is a first plateau (inclination=0 or only somewhat greater or somewhat less than zero) from the angle of rotation α0 to an angle of rotation α1. From the angle of rotation α1, the ramp track  53  has a first linear inclination portion S1 which is present as far as the angle of rotation α2. At the angle of rotation α2 (and the corresponding pitch height z1), the pitch merges into a second linear inclination portion S2 which has a greater inclination than the first linear inclination portion S1 (between the angles of rotation α1 and α2). The second inclination is present as far as the angle of rotation α3 and then merges into a second plateau in which the pitch height z2 does not increase (or only increases very slightly or only decreases very slightly) in the event of a further increase in the angle of rotation as far as the angle of rotation α4 of less than 360°. 
     At the angle of rotation α5, an edge  54  is formed because of the transition flank  46  which connects the second plateau to the first plateau. 
     In the region from α3 to α4, the piston rod  35  is in its tensioned basic position according to  FIG.  5   . The administering device  1  is therefore ready for the application of the liquid drug. 
     If the trigger  5  is then actuated and the triggering cage  21  is in the triggering position, the motor  12  rotates the ramp  52  further such that, when the angle of rotation α5 is exceeded, the roller  51  runs over the edge  54  and, because of the tensioning of the spring  41 , drops abruptly back from the pitch height z2 to the pitch height z0 of the first plateau, and therefore the fluid present in the syringe cylinder  16  is injected in the described manner. 
     The motor  12  then rotates the ramp  52  further as far as the second plateau and stops the rotational movement here such that the syringe cylinder  16  is thereby again filled with the liquid drug and the piston rod  35  is brought again into its tensioned basic position. The administering device  1  is therefore provided for a further administering operation. The administering device  1  can thereby be repeatedly wound up and triggered. 
     The two inclination portions S1 and S2 form a region of inclination which runs from the first plateau as far as the second plateau. The two inclination portions S1 and S2 do not have to run linearly with respect to the angle of rotation. As is shown by way of example in  FIG.  11 B , they can also have a concave curvature (at which the local inclination increases as the angle of rotation increases). However, even in this case, the average inclination of the first inclination portion S1 is smaller than the average inclination of the second inclination portion S2. 
     The combination of motor  12 , ramp  52 , driver  50  with roller  51 , spring  41 ,  141  and guide bushing  45 ,  145  can be referred to as the tensioning device S. 
     As can be gathered in particular from  FIGS.  12  and  13   , the roller  51  comprises a central region  55  which has a constant outside diameter. This is adjoined on both sides by a respective side region  56 ,  57  in which the outside diameter decreases toward the side. 
     The two side regions  56  and  57  are each adjoined by an end region  58 ,  59  which is rounded so that the roller  51  does not have any edges. Upon rotation of the ramp  52 , the central region  55  lies on the ramp track  53  in the rotational angle region of α1 to α3 (in particular of α0 to α5) whereas the side regions  56  and  57  do not rest in said rotational angle region, but rather come into contact with the ramp track  53  only on running over the edge  54 . The rolling resistance of the roller  51  during the tensioning of the piston rod  35  (rotation of the ramp track from the first to the second plateau) can therefore be as small as possible. During the transfer from the second or upper plateau (rotational angle region α3 to α4) of the ramp track  53  to the lower plateau (rotational angle region α1 to α2), the side regions  56  and  57  are also in contact with the edge  54 , as a result of which the forces between the roller  51  and the edge  54  of the ramp track  52  are advantageously distributed over a greater support surface (central region  55  and the two side regions  56 ,  57 ), and therefore a smaller pressure is present. The durability of the device  1  and in particular of the roller  51  is thereby increased. 
     The characteristics of the inclination of the ramp track  53  described in conjunction with  FIGS.  11 A and  11 B  are advantageous since, at the beginning (rotational angle region α1 to α2), there is a smaller inclination, and therefore less torque has to be provided by the motor  50 . This is of advantage precisely during the starting of the motor  50  from the first plateau since the motor  50  customarily draws more current in this region. When the pitch height z1 is reached, the higher inclination in the rotational angle region from α2 to α3 can easily be overcome by the motor  50 . 
     These characteristics of the inclination of the ramp track  52  advantageously lead to the durability of the motor  50  being increased. 
     As can best be gathered from the illustrations from  FIGS.  14  to  17   , the receiving block  10  is formed integrally. Here, for example, use has been made of an additive production method, such as, for example, laser sintering, selective laser sintering or direct metal laser sintering, with which finer and/or more complex structures can be produced in comparison to machining methods. The receiving block  10  can therefore be provided with a relatively low weight and it can be ensured that the administering device  1  is highly durable. 
     Examples of the material used for the receiving block  10  can include aluminum, steel (for example maraging steel), stainless steel, titanium, a nickel alloy and/or a cobalt chromium alloy. The material for the laser sintering here is preferably in the form of metal powder. For the additive or layered production of the receiving block  10 , a thin layer of the powder material can be applied to a construction platform. A laser beam melts the powder exactly at the points which are predetermined by computer-generated component design data of the receiving block  10 . The construction platform is then lowered, and a further thin layer of the powder material is applied. The material is melted again and binds at the defined points to the layer lying therebelow. These steps are repeated until the entire receiving block  10  is formed. 
     In addition to the receiving cylinders  40 ,  140  already described, the receiving block  10  comprises four board receiving points  60 ,  61 ,  62  and  63 , onto which the board  11  can be placed and, for example, screwed to the receiving block  10 . 
     Furthermore, the receiving block comprises a motor bearing  64  for receiving and mounting the motor  12 . 
     Furthermore, four fixation points  65 ,  66 ,  67  and  68  are formed for the outer housing  2  of the administering device  1 . Portions of corresponding receptacles  265 ,  266 ,  267  and  268  of the outer housing  2  are shown in  FIGS.  7  to  9   . 
     At the distal end of the receiving block  10 , the umbrella-like dispensing region  7  is provided which, in addition to the corresponding internal thread  31  and  131  for the first and second front assembly  13  and  14 , also has receptacles  69  and  169  for the respective triggering sensor (not shown) that detects the position of the triggering cage  21 ,  121 . 
     Furthermore, an O-ring receptacle  70 , into which an O-ring  71  (for example  FIGS.  9 ,  16  and  17   ) can be inserted, is formed in the dispensing region  7  in order to ensure sealing in relation to the adjacent housing  2  in the installed state. 
     Furthermore, the receiving block  10  for each receiving cylinder  40 ,  140  comprises a receptacle  72 ,  172 , into which the corresponding connection element  33 ,  133 , which can also be referred to as a fluid adapter, can be inserted. 
     The connection element  33 ,  133  is preferably produced by machining. 
     Titanium is preferably used as the material for the receiving block  10 . This material is firstly relatively light and secondly ensures the desired strength. Of course, any other suitable material for additive production methods may be used. 
     The description above has been based on the intention of simultaneously administering two different medications. However, the administering device  1  according to the invention may also be designed in such a manner that the receiving block  10  has only one individual receiving cylinder  40 , and therefore also only one single medication can be administered during a triggering operation. The second receiving cylinder  140  and the second cylinder-piston rod combination are then preferably omitted. 
     The previously described exemplary embodiments have been based on the administering device  1  being in the form of an administering device  1  without needles. However, it may also be in the form of an administering device  1  with a needle or a canula, and therefore, in this case, the needle or canula is intended to pierce the skin of the animal and then the application of the liquid drug takes place in the described manner.