examples of embodiments will be shown to provide an understanding of the principles of the design features , its function , manufacture , use of the device and methods disclosed . the embodiments shown are intended to be exemplary and non - limiting . the features described in the embodiment may be combined with variants or modifications of other embodiments to achieve the goals of a device with the features and novelties described . such variants or modifications are intended to be within the scope of the present disclosure . by way of a non - limiting example , fig1 a , 1b , 2 and 3 illustrate an apparatus 10 for delivering fluid from a fluid container according to one embodiment . apparatus 10 has a housing 13 , a slider 210 movably disposed in housing 13 and a resilient member 215 connected between the housing 13 and the slider 210 . in the present embodiment , housing 13 includes a hollow mandrel 101 and a sleeve 301 movably coupled to hollow mandrel 101 , and slider 210 is movably disposed in the hollow mandrel 101 . sleeve 301 has an entrance 307 formed at one end . entrance 307 includes a rim 308 extending radially and inwardly from side wall 306 of sleeve 301 , and an opening 309 surrounded by rim 308 . the resilient member is a thin , flat shaped tape spring 215 made of elastically deformable material , e . g . metal , and coiled to form a reel as shown in fig2 , 4 a and 4 b . spring 215 has a first end 217 at the outer end of the reel , and a second end 212 at the inner end of the reel . spring 215 is wound around an axle 216 at the second end 212 , and the axle 216 is attached to the slider 210 . a hollow core 218 may be used to support spring 215 and coupled to axle 216 via a bearing 219 . the first end 217 extends out of the slider 210 and is connected to the housing 13 i . e . in the present embodiment , the first end 217 is connected to the hollow mandrel 101 . the spring 215 is at the original , un - deformed state when coiled and with a major portion of the spring 215 received in the slider 210 , as shown in fig4 a and 4b . upon receiving an external force f 1 , the slider 210 moves relative to the hollow mandrel 101 away from the entrance 307 , causing the spring 215 to be pulled out and uncoil from the slider 210 and stores a potential energy in the spring 215 , as shown in fig5 . the potential energy will generate a driving force required to push fluid out of a fluid container , such as a syringe , attached to the apparatus 10 . the displacement of the slider 210 in the hollow mandrel 101 is constrained by guide channels 203 and 204 that could be made from separately formed parts installed within the inner walls of the hollow mandrel 101 , or the guide channels 203 and 204 could be integrated to the hollow mandrel 101 itself . the guide channels 203 , 204 assist in aligning the direction of the displacement of the slider 210 to be in a generally parallel direction as the axis of the plunger movement within the fluid container . the choice of the number of springs or its dimensions i . e . width , outer diameter , thickness and spring material determines the force that is desired . the axle 216 may be configured to be free to rotate relative to the slider 210 , to ease the spring 215 coiling and uncoiling about the axle 216 . alternatively , axle 216 may be fixed to slider 210 while the second end 212 of the spring 215 is rotatably attached around the axle 216 to maintain connection between the slider 210 and the spring 215 during coiling and uncoiling of the spring 215 around the axle 216 . in this embodiment , the constraints in the volume space of the hollow mandrel 101 corresponds to the use of a single spring , in order to provide a desired force for expelling fluid from a fluid container attached to the apparatus 10 . in other embodiments , the spring set could be a single spring or multiple springs arranged in appropriate configurations to provide desired force . by way of example , multiple springs could be arranged within a common axis or with their axes along the lateral direction in which they are displaced when the apparatus is in use . the mandrel 101 shown in fig4 a and 4b is at fully extended position out of the sleeve 301 . the slider 210 is disposed in mandrel 101 and movable relative to mandrel 101 long the channels 203 and 204 . when the spring 215 is coiled , a majority portion of spring 215 is wound around axle 216 and received in the slider 210 , while the slider 210 is located generally at the first position , adjacent to the entrance / open end 307 / 309 of the sleeve 301 as shown in fig4 a . when an external force f 1 is applied to slider 210 along direction 12 i . e . away from entrance 307 , the slider 210 will be pushed away from entrance 307 , as shown in fig5 . the sleeve 301 has helical thread grooves 305 formed on its inner sidewall . screw threads 105 of corresponding dimension and pitch are formed on the outer surface of the hollow mandrel 101 . engagement of the thread grooves 305 and screw threads 105 will allow rotation of the hollow mandrel 101 relative to the telescopic sleeve 301 and by such rotation , the hollow mandrel 101 will be moved relative to the sleeve 301 along axial direction 14 . the screw threads 105 could be a single loop or multiple loops around the outer circumference of the hollow mandrel 101 . as shown in fig6 and 7 ( a ) to 7 ( d ), in use , a syringe 40 is firstly filled with a desired amount of liquid medicine 401 in the barrel 406 . a tubing 415 connected to the nozzle 408 is then shut off , by a valve or clip 417 attached on tubing 415 to seal the liquid medicine 401 in the syringe 40 . as such , the plunger 402 is prevented from moving relative to barrel 406 . in this embodiment , a seat 211 is attached to the slider 210 , and is rotatable relative to slider 210 . the advantages of seat 211 is to reduce torsional forces acting on the plunger 402 by the slider 210 , when the mandrel 101 is rotated into the telescopic sleeve 301 . however , the slider 210 may also be directly engaged to the plunger , without the presence of seat 211 . the plunger 402 is then inserted through entrance 307 of sleeve 301 , into hollow mandrel 101 ( fig6 and 7 ( a )). after the plunger 402 and flange 403 pass through the entrance 307 , the barrel 406 of syringe 40 is twisted , by 90 degree for example , so that the oval - shaped flange 403 and similarly oval - shaped opening 309 are positioned with the longer axis of the flange 403 and the longer axis of the opening 309 aligned perpendicular to each other , to lock the barrel 406 to the sleeve 301 . other forms and means of affixing the syringe of other configurations may be adopted which should not be considered to be excluded from the scope as defined by the claims appended thereafter . once the barrel 406 is fixed to the sleeve 301 , as shown in fig7 ( b ), 7 ( c ) and 7 ( d ) , the mandrel 101 is rotated to move into the sleeve 301 , to bring the seat 211 of slider 210 into engagement with the plunger 402 . as the barrel 406 and plunger 402 are both relatively stationary with respect to the sleeve 301 since the valve or clip 417 is closed , further advancement of the mandrel 101 into the sleeve 301 will cause the slider 210 to move towards the closed end 103 of the mandrel 101 , resulting in the spring 215 being uncoiled and pulled out of the slider 210 , as shown in fig7 ( d ) . with the spring 215 uncoiled , there stores a potential energy in the spring 215 which generates a driving force f 2 acting against the plunger 402 , as shown in fig8 a . the apparatus 10 is now ready for delivering the fluid i . e . liquid medicine from the syringe 40 attached to the apparatus 10 . a shown in fig9 , when the valve or clip 417 is opened , driving force f 2 will prevail , which pushes the plunger 402 to move into the barrel 406 of syringe 40 , to expel the liquid medicine 401 out of the syringe 40 through nozzle 408 , to complete the fluid delivery . throughout the whole process of fluid delivery , the driving force f 2 is maintained at a substantial constant value , which enables the fluid to be delivered under a contact flow rate . the slider 210 could be affixed with a magnetic sensor 252 that is in communication with a magnetic linear strip 254 attached on the adjacent channel 203 and / or 204 of housing 13 . interaction of the sensor 252 and strip 254 could detect the position of the slider 210 relative to the mandrel 101 , which may be displayed on a screen 256 integrated on the apparatus 10 or onto a separate display 257 in signal communication with the sensor 252 . a shown in fig1 and 11 , projections or stubs 221 , 222 , 223 and 224 may be formed at the corners of the slider 210 to create a clearance or gap 226 between the main body portion 210 a of the slider 210 and the channels 203 , 204 that allows displacement sensors 252 to be installed . the communication between the displacement sensor 252 and the display screen 256 or 257 can be established by bluetooth , wifi or direct cable connections . a skilled person in the art should be able to extrapolate the data on position and or displacement of the slider 210 relative to the channel 203 / 204 to obtain valuable information like flow rate at which the fluid is expelled , volume expelled and volume remaining in the syringe . with a built in data base of drug dose limits , commonly known as drug library , the aforesaid data could be used to provide alarms for patient risk situations related to overdose or under dose . apparatus 10 may include a coupling element 209 positioned and connected between the slider 210 and the seat 211 . coupling element 209 is configured to cause the first end 217 of spring 215 to be positioned at a distance away from the initial unstressed position of the spring 215 within the hollow mandrel 101 , such that the total distance the axis of the springs traveled is longer than the displacement required for the plunger 402 to fully discharge the fluid from the syringe . in principle , the length of the coupling element 209 is configured to be sufficient to cause the spring 215 to be uncoiled from the slider 210 so that the driving force f 2 exerted on the plunger 402 would have already reached its constant level when fluid start to flow . typically this deflected length is about 1 to 1 . 5 times of the outer diameter of the spring 215 in coiled form . the coupling element 209 assists in generating a relatively more constant driving force acting on the fluid through the plunger , resulting in a relatively more constant flow profile during the fluid delivery , as shown in fig1 . fig1 shows a system 80 for fluid delivery . the system 80 includes an array of docking stations 50 each being connected to a display unit 60 that is connected to a controller 70 via a direct or wireless communication network and power supply cable , for use in e . g . a patient centre for automated medication service . each docking station 50 is configured to detachably hold an apparatus 10 and a syringe 40 attached to the apparatus 10 in a manner as illustrated above . in use , system 80 may be set up at a medical center or any suitable location for providing medication administration to patients . as shown in fig1 , a system 82 for fluid delivery includes one or more apparatus 10 as illustrated above , and a mobile platform 822 connected to each of the apparatus 10 with sensors and stripes installed thereon . displacement of the slider in each apparatus and flow rate data can be communicated to the mobile platform via wireless network protocols such as bluetooth , wifi and / or gsm , which are monitored and controlled for to increase the applicability of the apparatus for medicament delivery to patients .
an apparatus for delivering fluid from a fluid container comprises a housing to which a fluid container is attachable , a slider movably disposed in the housing and a resilient having a first end connected to the housing and a second end connected to the slider . upon receiving an external force , the slider moves relative to the housing from a first position toward a second position to deform the resilient member from an original state to a deformed state , and upon release of the external force , the resilient member is allowed to resume to the original state to move the slider toward the first position to urge the slider against the fluid container to deliver fluid from the fluid container under a constant fluid flow rate .