with reference to fig1 , a general inhaler 1 comprises a housing 2 having a mouthpiece 4 , which the user puts in his mouth when a dose of medicament is to be inhaled . the housing 2 of the inhaler is adapted to receive a standard canister 6 , containing liquid medicament , wherein the distal end of the canister 6 protrude a certain distance from the distal end of the housing 2 . the canister comprises a main canister body 8 that is adapted to communicate with a dose chamber 10 . the dose chamber 10 is in turn provided with a hollow spring - suspended transfer tube 12 provided with an outlet 13 in its proximal end . the dose chamber is further provided with an outlet valve 14 that is adapted to correspond to a valve 16 in the transfer tube 12 . the interior of the mouthpiece 4 is provided with a tubular receiving means 18 , having an inward protruding flange 20 , provided a predetermined distance from the bottom of the receiving means 18 . the receiving means 18 is further provided with an outlet 22 that communicates with the outlet of the mouthpiece 4 . the proximal end of the transfer tube 12 abuts against the flange 20 , such that a part of the outlet 13 of the transfer tube communicates with the outlet 22 of the receiving means . when a user of the inhaler intends to inhale a dose , he puts the mouthpiece in his mouth and applies a force , generally by the aid of his hand and fingers or the like , on the distal surface of the canister 6 , such that the canister body 8 and the dose chamber 10 is forced downwards towards the bottom of the housing 2 , i . e . towards the proximal end of the canister , while the transfer tube 12 remains still . thus , when the dose chamber 10 has moved a predetermined distance towards the bottom of the housing , the valve 16 of the transfer tube 12 will open communication with the valve 14 of the dose chamber , such that a metered dose of the pressurised liquid medicament contained in the main body 8 will flow from the dose chamber 10 , through the valves 14 , 16 , the transfer tube 12 , the outlets 13 , 22 and out through the outlet of the mouthpiece 4 . when the user releases the force applied to the distal end of the canister , the canister will move back to its original position . the distance between the valves 14 , 16 is a known predetermined distance , generally 2 mm , when the inhaler is in the first non activated state , i . e . the dose chamber needs to in a second activated state be forced downwards with a distance of 2 mm for the valves 14 , 16 to open communication with each other . it would be a simple case to construe a reliable dose counter device if the dimensions of the inhaler , would be exact dimensions . however , all dimensions of the general inhaler , such as the height of the main body a , the height of the dose chamber b , the length of the transfer tube c , the distance between the proximal end of the transfer tube and the distal edge of the housing d and the height of the dose counter means , are impaired by variation of not neglectable magnitude . if for instance the variation of the distances a , b , c , d is ± 0 . 4 mm , ± 0 . 05 mm , ± 0 . 25 mm , ± 0 . 2 mm , respectively and the variation of height of dose counter means is ± 0 . 1 mm , the sum of all margins of errors will be ± 1 mm . so , if one for instance construes a dose counter device that determines the distance that the canister has moved towards the bottom of the housing , dependent on a single reference point , for instance the distal edge of the housing 2 , and register a delivered dose when said distance amount to 2 mm , the dose may or may not have been delivered . also , the dose may have been delivered without the distance amounting to 2 mm . the solution to this problem , is according to a first and a second embodiment of the present invention an all mechanical solution , and is based on the idea , that during manufacturing of the dose counter device one establishes a fix known reference point , or reference distance that permits to determine an accurate distance that the canister has to be displaced within an inhaler before a delivered dose is registered . this offers a dose counter that compensates for the height dimension variations of the canister , the means of the dose counter and the arrangement between the canister and the inhaler housing , whereby erroneous counting of delivered doses from the canister is avoided . in fig2 is shown a calibrating means 36 of the dose counter device , having a sleeve - formed configuration . the interior of the calibrating means has inward preferably equally distributed protruding ribs 38 extending along the longitudinal axis of the means 36 . the ribs 38 preferably have a triangular shape and are manufactured of an easily deformable plastic material . the outer surface of the proximal end of the means 36 is provided with preferably two equally distributed outward protruding pins 40 . the calibrating means 36 is adapted to be mounted over the distal end of the inhaler housing 2 , as seen in fig3 . the ribs 38 will during this mounting procedure deform and break and the calibrating means will thus be tightly and not removably fitted on the inhaler housing 2 . this mounting procedure is a well controlled process so that the distance between the distal end of the calibrating means 36 and the distal end of the canister 6 , when the mounting procedure is finished , is a well defined and predetermined distance , indicated in fig3 by the letter e . in fig4 is shown a component adapted to be used in the present invention according to a first embodiment . said component is a driving means 42 having a sleeve - formed configuration designed in accordance with the calibrating means 36 . the interior surface of the means 42 is at its proximal end provided with a means ( not shown ) that corresponds to a means ( not shown ) on the exterior surface at the proximal end of the calibrating means , so that the driving means is adapted to be fitted over the calibrating means and at a place adapted to be rotated but not be movable along the longitudinal axis of the calibrating means . the exterior surface of the driving means 42 is further provided with a thread 44 , preferably having a variable pitch of grooving . as seen in fig4 , the pitch of grooving is finer towards the distal end of the driving means . the exterior surface of the distal end of the driving means is further provided with a number of equally distributed pins 46 having a bevelled edge at their distal end . the driving means is further at its distal end provided with upward protruding pins 50 . the pins 50 are at their distal end provided with triangularly shaped teeth 52 protruding towards the interior of the driving means . the driving means 42 of the first embodiment is adapted to be fitted in the interior of a house 54 shown in fig5 . the house is provided with a dose window 56 , and means that corresponds to the pins 40 of the calibrating means . in order for the driving means 42 to be fitted in the house 54 , the inner surface of the distal end of the house is thus provided with a means that corresponds to the means provided on the distal end of the driving means . so when the dose counter device according to the first embodiment is to be used , the driving means 42 is mounted in the interior of the house 54 , and the two components are mounted over the calibrating means already fitted with the inhaler housing , see fig6 . in fig6 it is shown that the interior surface at the distal end of the house 54 is provided with a downward protruding flange 58 , adapted to be in contact with the distal end of the canister 6 . that is , when the dose counter is mounted and ready for use , the distance between the distal end of the calibrating means and the distal end of the canister 6 , i . e . the proximal edge of the flange 58 and the distal end of the calibrating means is a known predetermined distance , i . e . the distance e . when the user of the inhaler intends to inhale a dose , he applies a force on the distal end of the house 54 , which thus moves towards the proximal end of the canister . the flange 58 will thus urge the canister downwards . the flange 58 is further provided with outwardly protruding triangularly shaped teeth 60 , which correspond to the teeth 52 of the driving means , as seen in fig6 and in fig7 , wherein the latter illustrates a cross section of the distal end of the dose counter device when mounted on top of an inhaler . the interior surface of the distal end of the house is further provided with inward protruding pins 62 having a bevelled edge at their proximal end that corresponds to the bevelled edge of the pins 46 on the driving means . when thus the house 54 is urged downwards , the bevelled edge of the pins 62 will move along the bevelled edge of the pins 46 and urge the driving means to rotate in the direction indicated by the arrow f in fig7 . since the height between the proximal end of the flange 58 and the distal end of the calibrating means is a known distance , i . e . the distance e , the dose counter device is so designed that the distance that one tooth 52 has to move in order to for its tip to meet the tip of a tooth 60 of the house 54 is a known predetermined distance that corresponds to a predetermined distance that the canister body then has moved towards the proximal edge of the inhaler . in this particular embodiment said distance is 1 mm . this is due to the fact that , when the user has pressed the canister downwards this particular distance , one can be pretty certain that he is to inhale a dose and that the downward movement of the canister was not as a result of general handling of the inhaler . thus , when the two tips of the teeth 52 , 60 meet , the tooth 52 will inevitably slide over the tooth tip 60 and the dose counter device has thus rotated one step and has accordingly registered a delivered dose . a more detailed description of the cooperation between the pins 46 and 62 is provided below in connection with the fig1 - 12 . the driving means is thus rotated one step when the house is applied with a force on its distal end that will urge a tooth 52 to slide over a tooth 60 . a dose indicating means 64 is provided over the thread 44 but provided in the dose window 56 . the means 64 thus rides along the thread when the driving means is rotated and moves down towards the proximal end of the dose window , indicating the dose remaining in the canister . in fig5 , the dose scale is seen provided as a progressive scale that corresponds to the variable pitch of grooving of the thread , but naturally the thread can have a non - variable pitch of a grooving , that corresponds to a non - progressive dose scale . preferably spring means ( not shown ) is provided between the inner distal end of the house and the distal end of the canister so that the house springs back towards the distal end of the inhaler when the user releases the force applied to the distal end of the house . according to a second embodiment of the present invention , the driving means and the interior of the house have slightly different configurations . in the following description of the second embodiment of the invention , components having essentially the same function as in the first embodiment but having a different configuration , have been designated the same reference number as in the first embodiment followed by a ‘- sign . components having essentially the same function and also essentially the same configuration , have accordingly been designated the same reference number as in the first embodiment . new components have naturally been designated new reference numbers . the driving means of the second embodiment , seen in fig8 , has thus accordingly been designated the reference number 42 ′. the driving means 42 ′ is adapted to be mounted over the calibrating means 36 as in the first embodiment . the difference between the driving means of the first and second embodiment , respectively , can be seen at the distal end of the driving means . instead of having the upward protruding pins 50 , provided with the inwardly protruding triangularly shaped teeth 52 , the driving means 42 ′ is provided with an upward protruding crown 66 . the crown is in turn on its distal edge provided with equally distributed upwardly protruding triangularly shaped teeth 52 ′. as in the first embodiment , the driving means 42 ′ is adapted to be fitted inside the house 54 ′. the difference between the house of the first and the second embodiment , respectively , is that no outward protruding triangularly shaped teeth 60 are provided in the house 54 ′. instead , a non - rotating means 68 is provided in the distal end of the interior of the house 54 ′, overlaying the driving means 42 ′ and the crown 66 . the proximal edge of the non - rotating means is provided with downward protruding triangularly shaped teeth 60 ′, that correspond to the teeth 52 ′ of the driving means 42 ′. the non - rotating means is provided as being suspended by a spring 70 . the spring 70 , preferably a helical steel spring is thus mounted between the inner distal surface of the house 54 ′ and the top of the non - rotating means . the non - rotating means 68 is not provided as a solid means but is provided with through going openings 72 . the number of openings 72 is in this particular embodiment four , such that the non - rotating means 68 when seen from above as in fig1 , can be seen as a means having a circular circumference provided with the openings 72 in the interior of the means . the demarcations between said openings thus constitute a cross - like shape . the spring 70 is thus provided as to operate between the centre of the cross 76 and the centre of the distal inner surface of the house 54 ′. the downward protruding flange 58 ′ of the house 54 ′ is thus designed in accordance with the non - rotating means 68 , such that when it is forced towards the proximal end of the inhaler , it is adapted to come in contact with the distal edge of the canister through the openings 72 of the means 68 . so , in the second embodiment when thus the house 54 ′ is urged downwards , the bevelled edge of the pins 62 of the house 54 ′ will move along the bevelled edge of the pins 46 and urge the driving means to rotate in the direction indicated by the arrow f in fig9 . the movement of the driving means to the left as seen in fig9 , will thus result in that a tip of a tooth 52 ′ also will move to the left urging the spring - suspended non - rotating means 68 up towards the distal end of the inhaler . since the height between the proximal end of the flange 58 ′ and the distal end of the calibrating means is a known distance , i . e . the distance e , the dose counter device is so designed that the distance that one tooth 52 ′ has to move in order to for its tip to meet the tip of a tooth 60 ′ is a known predetermined distance and that corresponds to a predetermined distance that the canister body then has moved towards the proximal edge of the inhaler . when a tip of a tooth 52 ′, meets a tip of a tooth 60 ′, the canister body has in this particular embodiment moved 1 mm towards the proximal end of the inhaler . this is due to the fact that when the user has pressed the canister downwards this particular distance , one can be pretty certain that he is to inhale a dose and that the downward movement of the canister was not as a result of general handling of the inhaler . thus , when the two tips of the teeth 52 ′, 60 ′ meet , the tooth 52 ′ will inevitably slide over the tooth tip 60 ′ and the dose counter device has thus rotated one step and has accordingly registered a delivered dose , as described in connection with the first embodiment . in fig1 - 12 , is seen the cooperation between the inward protruding pins 62 of the house 54 , 54 ′ and the pins 46 on the driving means 42 , 42 ′. the cooperation between the pins 62 and the pins 46 is the same in the first and the second embodiment , respectively , that is , said figures can be read also in connection with the first embodiment even though the non - rotating means 68 and its cooperation with the driving means 42 ′ is illustrated in the figures . now turning to fig1 ; when the house 54 , 54 ′ is urged downwards , the bevelled edge of the pins 62 will move along the bevelled edge of the pins 46 and thus urge the driving means to rotate in direction indicated by the arrow f . in fig1 is shown when the tip of a 52 ′ has met the tip of a tooth 60 ′, i . e . the non - rotating means is rotationally fixed but is moved towards the distal end of the canister against the spring force 70 as the tooth tip 52 ′ moves in the direction f . the distance that one tooth tip 52 , 52 ′ has to move in order to meet a tooth tip 60 , 60 ′ is designed so that it is in conformity with the predetermined distance that the pins 62 move towards the proximal end of the inhaler until a dose is registered as delivered , in this particular embodiment 1 mm . this is accomplished by for instance providing the bevelled edge of the pins 46 and 62 with the correct inclination , i . e . the correct value of the angle α . in fig1 is shown when one tooth tip 52 ′ has slid passed the tooth tip 60 ′, with which tip it was previously in contact with . due to the spring 70 , the non - rotating means will now be urged back downwards to its original position . as previously mentioned , when one tooth tip 52 , 52 ′ has slid passed its corresponding tooth tip 60 , 60 ′ a dose is registered as delivered . the user however , continues to urge the house and thus the canister towards the proximal end of the inhaler until the dose is actually delivered . the user then releases the force applied to the distal end of the house 54 , 54 ′, whereupon the canister and the house will move back to their original positions . due to the one step rotation of the driving means 42 , 42 ′, a pin 62 will the next time a dose is to be delivered , cooperate with the pin 46 following the pin it just previously cooperated with . the dose counter device is further preferably provided with means that prevent that the driving means is rotated in the wrong direction , which will result in a wrongful indication about the remaining doses in the canister . in fig1 is seen one embodiment of such wrong rotation direction preventing means 74 . the means 74 is here illustrated and described in connection with the second embodiment but as the skilled person readily understands , such means 74 can with minor adjustments very well be functional also with the first embodiment . in fig1 , the wrong rotation direction preventing means 74 can be seen as a slightly different configuration of the teeth 52 ′. the sides of teeth in line with the rotation direction f are unchanged . the other sides of the teeth however , do no longer have an even slope , but are provided with an upward protruding edge 74 , i . e . the teeth 52 ′ no longer have a triangular shape but the shape as seen in fig1 . the distal tip of the edge 74 now takes over the function of the tip of the tooth 52 ′. the driving means 42 ′ is in an effective way prevented to be rotated in the direction opposite to the direction f by means of the edge 74 . that is , a tooth 60 ′ can not slid pass such an edge 74 if the driving means is rotated in the direction that is opposite the rotation direction f . further , the solution to the mentioned problem in the introduction part , is according to a third embodiment of the present invention an all mechanical solution , and is based on the idea , that an actuating means , when depressed , travels a longitudinal distance until it makes contact with the distal end of the canister , to then interact with an intermediate means before a dose counter registers a delivered dose . this offers a dose counter that compensates automatically for the height dimension variations of the canister , the means of the dose counter and the arrangement between the canister and the inhaler housing , whereby erroneous counting of delivered doses from the canister are avoided . according to a third embodiment of the present invention , the driving means and the interior of the house have slightly different configurations . in the following description of the third embodiment of the invention , components having essentially the same function as in the second embodiment but having a different configuration , have been designated the same reference number as in the second embodiment followed by a “- sign . components having essentially the same function and also essentially the same configuration , have accordingly been designated the same reference number as in the second embodiment . new components have naturally been designated new reference numbers . the driving means of the third embodiment , seen in fig1 , has thus accordingly been designated the reference number 42 ″. the driving means 42 ″ is adapted to be mounted inside the house 54 ″. the difference between the driving means of the second embodiment and third embodiment , respectively , can be seen at the interior surface of the driving means wherein the distal end of the driving means 42 ″ has a larger diameter than the rest of the driving means 42 ″. further , the driving means 42 ″ is adapted to be mounted over the distal end of the inhaler housing 2 on a flange 55 at the proximal end of the house 54 ″. as in the second embodiment , the driving means 42 ″ is adapted to be fitted inside the house 54 ″. the difference , seen in fig1 , between the house of the second and the third embodiment , respectively , is that no inward protruding pins 62 are provided on the interior surface of the distal end of the house , that the distal part of the house has a larger diameter than the rest of the house 54 ″, that a through hole is provided at its top , that a slot 76 is provided in the interior surface at the distal end of the house and that slots 77 , seen in fig1 , are provided in the interior surface at the distal end of the house . in the third embodiment , seen in fig1 , the housing 2 is provided with preferably two equally distributed outward protruding pins 40 abutting against the slots 77 of the house 54 ″, instead of having those on the calibrating means 36 . further , in the third embodiment none calibrating means is required . as seen in fig1 , an intermediate means 69 is provided at its top with a through hole wherein said through hole has a certain diameter and height . said through hole may be provided with friction means as a ribbed interior surface or other types of engage means on its interior surface . further , said intermediate means 69 is provided on its interior surface with an inward flange 83 and with inward protruding pins 75 having a bevelled edge that corresponds to the bevelled edge of the pins 46 on the driving means 42 ″. the through hole of said intermediate means 69 has a slightly smaller diameter that the through hole of the house 54 ″. an outward flange 85 at the top of the intermediate means 69 abuts against the interior surface of the house 54 ″ wherein the edges of the through holes suit each other . further , said intermediate means 69 is provided on its exterior surface with an outward protruding ledge or pins 78 that corresponds to the slot 76 of the house 54 ″. as seen in fig1 , an spring 79 , preferably a helical steel spring is mounted in the slot 76 of the house 54 ″ between the outward protruding ledge or pins 78 of the actuating means 69 and a flange of the slot 76 at its distal end . further , the spring 79 may instead be mounted between the actuating means 69 , surrounding the outward flange 85 at the top of the intermediate means 69 and the interior surface of the top of the house 54 ″ ( not shown ). as seen in fig1 , an actuating means 71 is provided as a longitudinal sleeve 87 having bending walls of certain diameter and height . said longitudinal sleeve 87 being of a flexible material may be provided with friction means as a ribbed exterior surface on its bending walls or with other types of engage means on the exterior surface of its bending walls , as seen in fig1 . further , said actuating means 71 is arranged with an outward flange 80 having a slot 81 and a longitudinal extending sleeve 82 of certain diameter and height surrounding the canister 6 . further , said outward flange 80 abuts against the inward flange 83 of the intermediate means 69 . as seen in fig1 , a non - rotating means 68 ″ is provided in the distal end of the interior of the house 54 ″, overlaying the driving means 42 ″ and the crown 66 . the proximal edge of the non - rotating means is provided with downward protruding triangularly shaped teeth 60 ′, which correspond to the teeth 52 ′ of the driving means 42 ″. the distal edge of the non - rotating means is provided with a slot 86 . the non - rotating means 68 ″ is provided as a ring being depressed by a spring 73 . the spring 73 , preferably a helical steel spring is thus mounted between the slot 81 of the actuating means 71 and the slot 86 at the distal edge of the non - rotating means 68 ″. in the first and the second embodiments , the calibrating means 36 is adapted to be mounted over the distal end of the inhaler housing 2 . this must be a well controlled mounting procedure so that the distance between the distal end of the calibrating means 36 and the distal end of the canister 6 , is a well defined and predetermined distance , as indicated in fig3 by the letter e . this is not required in the third embodiment , since the actuating means 71 interacts with the intermediate means 69 and performs the calibration . so , in the third embodiment when the actuating means 71 is urged downwards , the spring 73 will be depressed and the spring 79 will urge the intermediate means 69 to move downward until the bevelled edges of the pins 75 will make contact with the bevelled edges of the pins 46 , as seen in fig1 . the outward flange 85 will come out of contact from the interior surface of the house 54 ″ and the actuating means 71 will continue to move downward until the outward flange 80 makes contact with the distal edge of the canister . then , the longitudinal sleeve 87 will bend its bending walls outwardly until its friction or engage means make contact with the friction or engage means of the intermediate means &# 39 ; s through hole , as seen in fig1 . this contact or engagement , will urge the intermediate means 69 to continue its downward movement until the bevelled edges of the pins 75 will move along the bevelled edges of the pins 46 and urge the driving means 42 ″ to rotate in the direction indicated by the arrow f in fig2 . the movement of the driving means to the left as seen in fig2 , will thus result in that a tip of a tooth 52 ′ also will move to the left urging the spring - suspended non - rotating means 68 ″ up towards the distal end of the inhaler . the dose counter device is designed so that the distance that one tooth 52 ′ has to move in order to for its tip to meet the tip of a tooth 60 ′ is a known predetermined distance and that corresponds to a predetermined distance that the canister body then has moved towards the proximal edge of the inhaler . when a tip of a tooth 52 ′, meets a tip of a tooth 60 ′, the canister body has in this particular embodiment moved 1 mm towards the proximal end of the inhaler . this is due to the fact that when the user has pressed the canister downwards this particular distance , one can be pretty certain that he is to inhale a dose and that the downward movement of the canister was not as a result of general handling of the inhaler . thus , when the two tips of the teeth 52 ′, 60 ′ meet , the tooth 52 ′ will inevitably slide over the tooth tip 60 ′ and the dose counter device has thus rotated one step and has accordingly registered a delivered dose , as described in connection with the first embodiment . although the present invention has been described with reference to preferred embodiments , those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention . as such , it is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is the appended claims , including all equivalents thereof , which are intended to define the scope of the invention .
the invention refers to a dose counter device for an inhaler that in a reliable way will register a delivered dose from a canister comprised in the inhaler , and that at the same time substantially will reduce the risk of falsely register a dose not delivered . thus , the present invention will in an effective way , substantially avoid erroneous counting of delivered doses from the canister .