Abstract:
A peristaltic pump includes a driver, a pump body, a hose, a rotor and a connecting member. The driver includes a supporting shaft. The pump body includes a chamber housing the rotor. The hose is assembled to an internal side of a wall of the chamber. The connecting member connects the driver with the rotor, and is received in the chamber. The rotor is configured to sequentially squeeze the hose to cause medium in the hose to flow. The connecting member and the rotor rotate about and are supported by the supporting shaft. The medical peristaltic pump has a simple structure and is easy to operate.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional patent application claims priority under 35 U.S.C. §119(a) from Patent Application No. 201410484639.1 filed in The People&#39;s Republic of China on Sep. 19, 2014, the entire contents of which are hereby incorporated by reference. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to a medical device and in particular, to a medical peristaltic pump, such as a blood pump. 
       BACKGROUND OF THE INVENTION 
       [0003]    A peristaltic pump, also known as a hose pump, is a type of industrial pump which is used extensively in medical, food, and chemical industries to transport medium which is sensitive, viscous, strongly corrosive, provides grinding effect, has a high purity requirement, or contains a certain amount of granular substances. 
         [0004]    A hose is the only essential element of the peristaltic pump for receiving liquid, and a roller or a pressing block squeezes the hose to cause the liquid within the hose to flow. The hose is an independent unit, eliminating the requirement for a hermetically sealed pump body. Therefore, the peristaltic pump is leak-free and very sanitary. In addition, a constant volume of liquid is outputted each time the roller is rotated, enabling the peristaltic pump to provide an outstanding performance in the application of quantifying feed. 
         [0005]    However, the structure of the peristaltic pump is complex, with gears of the driver arranged to turn the rotor to which the rollers are fixed, being exposed within the pumping chamber and thus exposing the operator to possible injury when changing the hose. 
       SUMMARY OF THE INVENTION 
       [0006]    There is a desire for a medical peristaltic pump, which has a simplified structure and improved safety, or at least provides the public with a useful choice. 
         [0007]    Accordingly, in one aspect thereof, the present invention provides a medical peristaltic pump, comprising: a driver, comprising a supporting shaft; a pump body, comprising a chamber; a rotor received within the chamber; a hose assembled to an internal side of a wall of the chamber; and a connecting member connecting the driver with the rotor, and being received in the chamber; wherein the rotor is configured to sequentially squeeze the hose to cause medium in the hose to flow, the supporting shaft supports the connecting member and the rotor, and the connecting member and the rotor are arranged to rotate about the supporting shaft. 
         [0008]    Preferably, the rotor is detachably mounted to the connecting member. 
         [0009]    Preferably, the connecting member comprises a plurality of latching claws, the rotor comprises a plurality of locking members, each latching claw is provided with a barb/a latching cutout, each locking member is provided with a latching cutout/a barb to latch with the corresponding barb/latching cutout. 
         [0010]    Preferably, the rotor comprises a main body, the main body defines a receiving groove for the latching claw, the main body defines a guiding groove, the locking member being slidable within the guiding groove, a resilient member is provided between the locking member and the main body, the resilient member pushes the locking member to maintain the locking member in a position which allows the latching cutout/barb of the locking member to latch with the corresponding barb/latching cutout. 
         [0011]    Preferably, the connecting member is provided with at least one step to position the rotor axially relative to the chamber. 
         [0012]    Preferably, the rotor comprises a main body, a sliding block capable of sliding relative to the main body, a roller assembled to a terminal end of the block, and a spring arranged to move the sliding block radially outwardly to urge the roller into contact with the hose. 
         [0013]    Preferably, the main body comprises at least one positioning surface, the sliding block defines at least one abutting surface, the abutting surface of the sliding block engages with the corresponding positioning surface of the main body, thereby positioning the sliding block. 
         [0014]    Preferably, the pump body further comprises a cover configured to cover the chamber, the cover is connected to the chamber by a hinge. 
         [0015]    Preferably, the pump body further comprises a cover for covering the chamber, and an electromagnetic locking mechanism is provided between the cover and the chamber. 
         [0016]    Preferably, one of the cover and the chamber is equipped with a permanent magnet, the other one is equipped with a sensor, and the sensor interacts with the magnet to sense an open or close state of the cover. 
         [0017]    Preferably, the driver comprises an electric motor and a gear reduction mechanism, the gear reduction mechanism comprises an output gear, the output gear is disposed outside the chamber and fixedly connected to the connecting member. 
         [0018]    Preferably, the rotor comprises a cover plate, and the cover plate has a handle for manual rotation of the rotor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A preferred embodiment of the invention will now be described, by way of example only, with reference to figures of the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same reference numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. 
           [0020]      FIG. 1  illustrates a medical peristaltic pump in accordance with an embodiment of the invention; 
           [0021]      FIG. 2  is a partially exploded view of the medical peristaltic pump of  FIG. 1 , with a cover opened; 
           [0022]      FIG. 3  is an exploded view of a rotor and a connecting member of the medical peristaltic pump of  FIG. 1 ; 
           [0023]      FIG. 4  shows a locking member of the rotor of  FIG. 3 ; 
           [0024]      FIG. 5  shows the rotor of the medical peristaltic pump of  FIG. 1 , with a rotor cover removed to show an internal structure of the rotor; and 
           [0025]      FIG. 6  is a sectional view of the rotor of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring to  FIGS. 1 and 2 , a medical peristaltic pump in accordance with an embodiment of the invention includes a driver  10 , a pump body  30  and a hose  60 . 
         [0027]    The driver  10  includes an electric motor  12 , and a gear reduction mechanism  14  driven by the electric motor  12 . 
         [0028]    The pump body  30  includes a chamber  32 , and a rotor  40  received in the chamber  32 . The rotor  40  is configured to squeeze the hose  60 , so as to cause the (liquid) medium, such as blood, within the hose  60  to flow. The chamber  32  includes an arc wall  34 , and a portion of the hose  60  closely contacts an internal surface of the arc wall  34 . The internal surface of the arc wall  34  is a portion of a cylindrical surface. A center of the internal surface coincides with a center of the rotor  40 . 
         [0029]    The gear reduction mechanism  14  includes a supporting shaft  16  and an output gear  18  (see  FIG. 3 ). A connecting member  70  is fixedly connected to the output gear  18 . The supporting shaft  16  extends through the output gear  18  and the connecting member  70 , thereby allowing the output gear  18  and the connecting member  70  to rotate about the supporting shaft  16 . The connecting member  70  is received in the chamber  32 , the rotor  40  is detachably connected to the connecting member  70 , thereby the rotor  40  can be fixed to rotate with the output gear  18  via the connecting member  70 . The output gear  18  is shielded at a side of a bottom plate  33  of the chamber  32  remote from the rotor  40 , i.e. the output gear  18  is disposed outside of the chamber  32 , such that the output gear  18  is protected and the user is prevented from being hurt by the output gear  18 . 
         [0030]    Referring to  FIG. 3  and  FIG. 4 , the connecting member  70  includes a plurality of latching claws  72  latching with the rotor  40 . Each latching claw  72  is provided with a barb  74  at a terminal end thereof. The rotor  40  includes a plurality of locking members  42 , and each locking member  42  defines a latching cutout  44  for latching with the barb  74 . The rotor  40  further includes a main body  46 . The main body  46  defines a groove  462  ( FIG. 6 ) extending in an axial direction of the main body  46 , for insertion of the latching claw  72 . The main body  46  defines a guiding groove  48  at a portion corresponding to the locking member  42 . The locking member  42  can slide within the guiding groove  48 . A resilient member such as a spring  49  is disposed between the locking member  42  and the main body  46  in a resiliently compressed condition. The spring  49  urges the locking member  42  to remain in a position that enables the barb  74  of the connecting member  70  to latch with the latching cutout  44  of the locking member  42 . 
         [0031]    Specifically, the locking member  42  defines two latching cutouts  44 , and a bottom of an end of each latching cutout  44  adjacent to the spring  49  is provided with a blocking plate  45  extending from a side wall of the latching cutout  44  toward the latching cutout  44 . On application of an external force, the locking member  42  is moved against the force of the spring  49  and slides inwardly relative to the main body  46 , enabling the blocking plate  45  in the latching cutout  44  to move away from the barb  74 , allowing the latching claw to enter the latching cutout  44 . Once the barb  74  clears the blocking plate  45 , the spring returns the latching member to the locked position capturing the latching claws contact between the blocking plate and the barb. Under the urgings of the spring  49 , the locking member  42  comes back to an original position, the barb  74  of the connecting member  72  resists against the block plate  45  of the latching cutout  44 , thereby securing the connecting member  70  to the rotor  40  to enable the rotor  40  to rotate together with the connecting member  70 . In the illustrated embodiment, the spring  49  is positioned between a central portion of the main body  46  and an internal end portion of the locking member  42 . The spring  49  pushes the locking member  42  outward. The barb  74  of the connecting member  70  resists an internal side wall of the latching cutout  44 , i.e. the barb  74  contacts the side wall nearest to the center of the main body  46 , to prevent the locking member  42  which is under the urging of the spring  49  from sliding outward excessively and disengaging from the rotor main body. Depressing the latching member against the urging of the spring releases the latching claws allowing the rotor to be disconnected for the connecting member. 
         [0032]    Preferably, the connecting member  70  includes two latching claws  72 , and each latching claw  72  is provided with a pair of barbs  74  at an end portion thereof. Each locking member  42  defines a pair of latching cutouts  44 , and each pair of the barbs  74  is positioned within a corresponding latching cutout  44 . Such arrangement can strengthen a connection between the connecting member  70  and the rotor  40 . 
         [0033]    The connecting member  70  further includes a connecting portion  76 . Preferably, the connecting portion  76  is annular in shape, with a though hole defined in a center thereof The output gear  18  of the driver  10  is fixedly assembled to the end of the connecting portion  76  remote from the latching claw  72 . The supporting shaft  16  extends though the output gear  18  and the connecting portion  76 , thereby rotatably supporting the output gear  18  and the connecting member  70 . 
         [0034]    The connecting member  70  is provided with at least one step to position an axial portion of the rotor  40  in the chamber  32 . In the embodiment, an end of the connecting portion  76  of the connecting member  70  adjacent to the latching claw  72  is provided with a protruded step  78  at a center thereof The latching claw  72  is also provided with a step  78  at a position adjacent to the barb  74 , the step  78  abuts against the main body  46  of the rotor  40  (see  FIG. 6 ). The engagement between the barb  74  and the step  78  can define the axial position of the rotor  40  relative to the connecting member  70 . 
         [0035]    Referring to  FIG. 5 , the rotor  40  further includes a plurality of sliding blocks  50  which can slide relative to the main body  46 , a plurality of rolling posts or rollers  52  assembled to a terminal end of the sliding block  50 , which can rotate relative to sliding block  50 , and a spring  54  positioned between the central portion of the main body  46  and the internal end of the sliding block  50 . The spring  54  urges the sliding block  50  outwardly to enable the roller  52  to squeeze the hose  60 . Specifically, the main body  46  defines a receiving space receiving the sliding blocks  50 , the sliding blocks  50  can slide within the receiving space. The sliding block  50  is provided with a shoulder portion  56 , and the main body  46  defines an arc positioning surface  464  corresponding to the shoulder portion  56  of the sliding block  50 . The shoulder portion  56  defines an abutting surface  564  configured to contact the positioning surface  464 , and the abutting surface  564  has a shape corresponding to the shape of the positioning surface  464  of the main body  46 . The positioning surface  464  engages with the shoulder portion  56  of the sliding block  50  to limit a maximum distance of movement of the sliding block  50 , thereby controlling the utmost position of the roller  52 . Preferably, the plurality of arc positioning surfaces  464  of the main body  46  are located on a coaxial circle having a center on the axis of the rotor. The center of the coaxial circle is on the axis of the supporting shaft  16 , i.e. the center of the rotor  40 . This facilitates keeping a concentricity of the plurality of the sliding blocks  50 , i.e. keeping the distances uniform between the utmost edges of the rollers  52  on the plurality of the sliding blocks  50  and the center of the rotor  40 , thereby maintaining the same squeezing force of the rollers  52  of different sliding blocks  50  on the hose to achieve the constant medium flow. 
         [0036]    Referring to  FIG. 2 , the hose  60  is arranged in a substantially U shape, and assembled to the inner side of the side portion of the chamber  32 . In operation, the output gear  18  of the driver  10  drives the rotor  40  to rotate via the connecting member  70 , and the rollers  52  on the rotor  40  squeeze the hose  60  along the extending direction of the hose  60 , thereby pushing the medium in the hose  60  to move along the hose in the direction of rotation of the rotor  40 . 
         [0037]    The rotor  40  further includes a cover plate  47 . The cover plate  47  is fixed to the main body  46  via a fixing member such as a screw. A side of the cover plate  47  remote from the main body  46  is provided with a handle  472 , such that when the driver  10  stops working, the user can use the handle  472  to turn the rotor  40 . 
         [0038]    The pump body  30  further includes a cover  36  configured to cover the chamber  32 . The cover  36  is connected to the chamber  32  by a hinged connection. 
         [0039]    Preferably, an electromagnetic lock is provided between the cover  36  and the chamber  32 . A permanent magnet  362  is fixed to one of the cover  36  and the chamber  32 , and a sensor  322  such as a Hall sensor is assembled to the other one. When the cover  36  is closed, the sensor  322  generates a signal to indicate that the cover  36  is closed. When the cover  36  is open, the sensor  322  generates another signal to indicate that the cover  36  is open. 
         [0040]    The medical peristaltic pump of the invention is specially suitable for use as a blood pump. When serving as a blood pump, the rotating rate of the output gear  18  is preferably 80-120 revolutions/minute (RPM). 
         [0041]    In the description and claims of the present application, each of the verbs “comprise”, “include”, “contain” and “have”, and variations thereof, are used in an inclusive sense, to specify the presence of the stated item or feature but do not preclude the presence of additional items or features. 
         [0042]    It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. 
         [0043]    The embodiments described above are provided by way of example only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims. 
         [0044]    For example, the locking member and the connecting member can be connected in different detachable connecting manners. When the engagement between a latching hook and a latching cutout is adopted, the positions of the latching hook and the latching cutout are not intended to be limited to any particular positions described above. The latching hook can be positioned on one of the locking member and the connecting member, and the latching cutout can be positioned on the other one. It can also adopt an engagement between a latching hook and a latching clip. These all fall within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the claims that follow.