PATENT ABSTRACT
A peristaltic pump is provided. The peristaltic pump includes a housing for a motors a receiving plate mounted to the housing, a locking plate, and a biasing member. The locking plate includes a first aperture capable of receiving a hook extending from a pump head, a second aperture capable of receiving a drive shaft of the pump head, and a release member. The biasing member elastically couples the receiving plate with the locking plate. Use of the release member by a user causes movement of the locking plate relative to the receiving plate to release the hook when received in the first aperture thereby releasing the pump head from the locking plate.

PATENT DESCRIPTION
FIELD  
       [0001]     The field of the disclosure relates generally to peristaltic pumps. More specifically, the disclosure relates to a peristaltic pump head that can be mounted to the peristaltic pump using an elastically displaceable locking plate.  
       BACKGROUND  
       [0002]     Peristaltic pumps have been known for many years, and are commonly used for medical and research purposes. Peristaltic pumps are used, in particular, in research, environmental science, and chemistry laboratories, and in the pharmaceutical, biotechnology, agriculture, and food industries. Peristaltic pumps move a liquid through a tube without any part of the pump touching the liquid. As a result, it is possible to pump liquids, such as blood, which are sensitive to external contamination.  
         [0003]     Typically, a pump comprises rotating rollers that compress a part of the flexible tube as they move to propel the liquid through the tube. Some peristaltic pumps have at least one removable head through which passes the tube in which the fluid flows. The rollers mount on the periphery of a central hub of the head and are driven to rotate thereby compressing the tube in succession against a fixed wall. The alternation of pressure and release phases of an area of the tube pumps the fluid to be delivered.  
         [0004]     Some peristaltic pumps include a plurality of heads which can be mounted adjacent to each other and driven to rotate by the same actuator. As a result, the first head of the stack can be fixed on a module having a motor connected to means for driving the central hub of the head. Any remaining heads can be fastened in succession, starling at the front face of the first head. Each head is also connected to the means for driving the central hub of the preceding head. Inclusion of a plurality of heads enables the supply of a fluid using a single drive module. This is particularly useful, for example, in animal testing laboratories, so that a plurality of animals can receive the same dose of the same liquid at the same time. Peristaltic pumps with stackable heads are described, for example, in EP-A-0 61 9 859 and EP-A-0 339 857. What is needed, however, is a peristaltic pump with stackable heads in which the heads can be very easily added to and/or removed from the pump, particularly without interrupting the operation of the pump for such addition or removal.  
       SUMMARY  
       [0005]     A peristaltic pump including a mechanism for adding and/or removing one or more pump heads to/from the peristaltic pump is provided in an exemplary embodiment. The peristaltic pump includes, but is not limited to, a housing for a motor, a receiving plate mounted to the housing, a locking plate, and a biasing member. The locking plate, includes, but is not limited to, a first aperture capable of receiving a hook extending from a pump head, a second aperture capable of receiving a drive shaft of the pump head, and a release member. The biasing member elastically couples the receiving plate with the locking plate. Use of the release member by a user causes movement of the locking plate relative to the receiving plate to release the hook when received in the first aperture thereby releasing the pump head from the locking plate.  
         [0006]     Another exemplary embodiment provides a peristaltic pump. The peristaltic pump includes, but is not limited to, a housing for a motor, a receiving plate mounted to the housing, a locking plate, and a biasing member. The locking plate, includes, but is not limited to, a hook, an aperture capable of receiving a drive shaft of a pump head, and a release member. The biasing member elastically couples the receiving plate with the locking plate. Use of the release member by a user causes movement of the locking plate relative to the receiving plate to release the hook from the pump head when the pump head is mounted to the locking plate.  
         [0007]     Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description, and the appended claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     Exemplary embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like numerals denote like elements.  
         [0009]      FIG. 1  is a perspective view of a peristaltic pump including a plurality of pump heads in a position to be installed onto the pump and a pump head mounted to the peristaltic pump in accordance with an exemplary embodiment.  
         [0010]      FIG. 2  is a perspective view of a mounting side of a pump head in accordance with an exemplary embodiment.  
         [0011]      FIG. 3  is a perspective view of the pump head of  FIG. 1  showing detail of the drive shaft of the pump head in accordance with an exemplary embodiment.  
         [0012]      FIG. 4  is a perspective view of a receiving plate of the pump drive module of  FIG. 1  without a pump head mounted to the drive module in accordance with an exemplary embodiment.  
         [0013]      FIG. 5  is a perspective view of the drive module of  FIG. 4  showing detail of the drive shaft of the drive module in accordance with an exemplary embodiment.  
         [0014]      FIG. 6  is a perspective view of the drive module of  FIG. 4  showing detail of the mounting mechanism for mounting a pump head to the drive module in accordance with an exemplary embodiment.  
         [0015]      FIG. 7  is a back perspective view of the mounting mechanism of  FIG. 4  with a pump head mounted to the drive module in accordance with an exemplary embodiment. 
     
    
     DETAILED DESCRIPTION  
       [0016]     With reference to  FIG. 1 , a peristaltic pump  30  is shown in accordance with an exemplary embodiment. Peristaltic pump  30  may include a drive module  1 , a first pump head  32 , a second pump head  34 , and a third pump head  36 . Drive module  1  includes a housing  38  which encloses a motor. The motor drives a central hub of the pump heads  32 ,  34 ,  36 . Housing  38  includes a control panel  4  and a display screen  5  which enable an operator to adjust operating parameters of peristaltic pump  30 . A receiving plate  6  mounts to housing  38 . Receiving plate  6  includes an upper face  2  on which a push button  3  is mounted. Using push button  3 , the operator can release first pump head  32 , or a stack of pump heads connected to drive module  1  as described below. Receiving plate  6  is mounted on drive module  1 . As used in this disclosure, the term “mount” includes join, unite, connect, associate, insert, hang, hold, affix, attach, fasten, bind, paste, secure, bolt, screw, rivet, solder, weld, and other like terms.  
         [0017]     First pump head  32  includes a cassette  40 , a second push button  9 , and a second receiving plate  10 . Cassette  40  includes an orifice  7  and a slide control  8 . Cassette  40  allows a flexible tube (not shown) to be inserted into it in a conventional way through orifice  7 . Slide control  8  can be used, also in a conventional way, to adjust the positioning of the internal members of cassette  40  to provide a permanent contact with sufficient pressure between these members and the tube inserted into orifice  7 , regardless of the diameter of the tube used. The internal members of cassette  40  are essentially a central hub driven by drive module  1  and its peripheral cylinders which periodically compress the wall of the tube, thus creating the flow of the fluid to be delivered. Cassette  40  is of conventional design, and therefore will not be described or illustrated here. The previously cited prior art documents provide example embodiments of these internal members, whose general design can be included within the scope of the invention in a non-restrictive way. Second push button  9  can be used to unlock the pump heads mounted on second receiving plate  10  of first pump head  32 , by means of a mechanism which is described below.  
         [0018]     Second pump head  34  is shown ready for mounting on second receiving plate  10  of first pump head  32 . In the exemplary embodiment of  FIG. 1 , second pump head  34  includes four cassettes  40 , a mounting plate  11 , a third push button  9 ′, and a third receiving plate  10 ′. Each of the four cassettes  40  include an orifice  7 ′. As a result, four flexible tubes, instead of one, can be inserted into second pump head  34 . Third push button  9 ′ can be used to release the pump heads mounted on third receiving plate  10 ′ of second pump head  34 .  
         [0019]     Third pump head  36  is shown ready for mounting on third receiving plate  10 ′ of second pump head  34 . In the exemplary embodiment of  FIG. 1 , third pump head  36  includes two cassettes  40 ′, a second mounting plate  12 , a fourth push button  9 ″, and a fourth receiving plate  10 ″ Each of the two cassettes  40 ′ include an orifice  7 ″. As a result, two flexible tubes, instead of one, can be inserted into third pump head  36 . In the exemplary embodiment of  FIG. 1 , the two orifices  7 ″ allow the passage of two flexible tubes of larger diameter than the tubes which can pass through the orifices  7 ,  7 ′. As a result, third pump head  36  may be as thick as second pump head  34 , which allows the passage of four smaller-diameter tubes. Fourth push button  9 ″ can be used to release any additional pump heads which may be mounted on fourth receiving plate  10 ″ of third pump head  36 .  
         [0020]     With reference to  FIG. 2 , a perspective view of second pump head  34  is shown in accordance with an exemplary embodiment. A face  13  of mounting plate  11  is shown. Second mounting plate  12  and/or receiving plate  6  may include a similar face  13  for mounting to another pump head. Face  13  includes a plurality of hooks  17  which extend from the surface of face  13  opposite cassettes  40 . Face  13  also includes an aperture  42  through which an end of a drive shaft  14  of the central hub of second pump head  34  extends The plurality of hooks  17  allow the operator to fasten second pump head  34  either to a front face  18  of receiving plate  6  or to a mounting plate of another pump head.  
         [0021]     With reference to  FIG. 3 , aperture  42  of face  13  is shown in greater detail. Drive shaft  14  includes splines  15  formed by longitudinal protrusions whose ends have chamfers  16 , the function of these being described below.  
         [0022]     With reference to  FIG. 4 , housing  38  with front face  18  of receiving plate  6  visible is shown in accordance with an exemplary embodiment. Receiving plate  6  includes an aperture  44 . An end  19  of the shaft driven by the motor of drive module  1  is accessible through aperture  44 . A locking plate  22  mounts to receiving plate  6  and includes push button  3 . Depression of push button  3  causes displacement elastically and releases a pump head connected to drive module  1 . In the exemplary embodiment of  FIG. 4 , locking plate  22  includes four locking apertures  23  in which the plurality of hooks  17  of the mounting plate engage. With reference to  FIG. 6 , the entrance of each of the four locking apertures  23  includes a chamfer  24  which facilitates the introduction of the corresponding hook  17 .  
         [0023]     With reference to  FIG. 5 , end  19  of the shaft is shown in greater detail. End  19  is shaped in the form of a sleeve whose inner surface has second splines  20  formed by longitudinal protrusions whose ends have chamfers  21 . Second splines  20  are designed to receive between them splines  15  of the end of drive shaft  14  of second pump head  34 . Drive shaft  14  is mounted to the shaft of drive module  1 . The chamfers  15  and  21  facilitate the reception of drive shaft  14  of the head into the sleeve of end  19 . As a result, drive shaft  14  can be received into end  19  without the need to stop the motor of drive module  1 .  
         [0024]     With reference to  FIG. 7 , a perspective view of locking plate  22  mounted to receiving plate  6  is shown in accordance with an exemplary embodiment. Push button  3  extends from locking plate  22  through an aperture in upper surface  2  of receiving plate  6 . Locking plate  22  includes the four locking apertures  23 , an aperture  46 , and apertures  28 . End  19  of the shaft driven by the motor of drive module  1  extends through aperture  46 . Locking plate  22  tends to be pushed upwards by biasing members  25 ,  26 , being guided for this purpose by fixed studs  27 , which extend from receiving plate  6  and penetrate into apertures  28  of locking plate  22 . Biasing members  25 ,  26  may be springs.  
         [0025]     A pump head is mounted to receiving plate  6  by a simple axial movement to engage the plurality of hooks  17  with the chamfers  24  of the four locking apertures  23  of locking plate  22 . The plurality of hooks  17  tend to push locking plate  22  downwards to allow passage through the four locking apertures  23 . At this point, the springs  25  and  26  push locking plate  22  upwards again locking the plurality of hooks  17  against the four locking apertures  23  of locking plate  22 . In the absence of the chamfers  24  or similar chamfers which may be formed on the plurality of hooks  17 , it may be necessary to press push button  3  to align the plurality of hooks  17  with the four locking apertures  23 . Release of push button  3  locks the plurality of hooks  17  against the four locking apertures  23 . At the same time, the end of drive shaft  14  of the pump head penetrates into the end  19  of the shaft of the motor of drive module  1 , and the two shafts engage each other. Thus, a rotation of the motor shaft causes a rotation of the drive shaft of the pump head.  
         [0026]     A subsequent depression of push button  3  releases the plurality of hooks  17  from the four locking apertures  23 . Locking plate  22  is pushed back downwards, thus releasing the plurality of hooks  17  and the pump head from drive module  1  by pulling away from drive module  1 .  
         [0027]     The receiving plate  10 ,  10 ′,  10 ″ of each pump head  32 ,  34 ,  36  is advantageously shaped in the same way as receiving plate  6  and similarly includes a locking plate mounted thereto as described above. in particular, each receiving plate  10 ,  10 ′,  10 ″ includes a locking plate identical to locking plate  22  including the four locking apertures  23  and push buttons  9 ,  9 ′,  9 ″ corresponding to push button  3  of drive module  1 . Thus, a plurality of pump heads  34 ,  36  can be mounted in a sequence starting with first pump head  32 . The front end of drive shaft  14  of the central hub of each pump head  32 ,  34 ,  36  is shaped in the same way as end  19  of the shaft of the motor of drive module  1 , so that the shaft of the central hub of a given pump head  32 ,  34 ,  36  receives into itself the shaft of the central hub of the following pump head in the stack to drive the subsequent shaft under control of the motor. Thus, any number of pump heads can be mounted in sequence with the only limitation being the driving power of the motor of drive module  1 . Mounting of the pump heads can occur with the motor stopped or with the motor running. This result is achieved, in particular, by the chamfered configuration of the splines  15 ,  20  of the ends of the shafts, which facilitate engagement, even when there is no exact alignment between the shafts.  
         [0028]     If a plurality of additional pump heads  34 ,  36  are mounted on first pump head  32  connected to drive module  1 , push button  3  of drive module I can be depressed to release the whole stack of heads  32 ,  34 ,  36  while keeping them connected to each other. it is also possible to unlock a single head  32 ,  34 ,  36 , or a group of consecutive pump heads, without any need to stop drive module  1 . In alternative embodiments, the use of a head which has a mounting plate, but not a receiving plate can be used. in this case, the pump head is the last head of the stack, or the only head connected to drive module  1 .  
         [0029]     Various modifications are possible. For example, a smaller or a greater number of the hooks  17  and the apertures  23  may be used in a different configuration. Additionally, the direction of displacement of locking plate  22  can be changed, together with the shapes of the hooks  17  and the apertures  23 . Push buttons  3 ,  9 ,  9 ′,  9 ″ can be replaced with any functionally equivalent means enabling the user to displace the locking plates  22 . Relative to the method of connecting the shafts  14  of the central hubs of the heads  32 ,  34 ,  36  to each other and to the motor shaft driven by the motor, their precise configurations can vary. For example, the positions of the sleeve on end  19  (and its corresponding parts on the pump heads  32 ,  34 ,  36 ) and the end  14  of the shaft, which interacts with it, can be reversed. In particular, the respective positions of the locking plates  22 , the hooks  17  and the corresponding apertures  23  can be reversed. In this case, the locking plates  22  and the apertures  23  are placed on faces  13  of the mounting plates of the pump heads  32 ,  34 ,  36  and the hooks  17  are placed on the receiving plates. The configuration described and illustrated above is the most advantageous, in that it provides drive module  1  with a front face  18  free of fragile projecting elements, the breakage of which as a result of an impact would make drive module  1  unusable.  
         [0030]     The foregoing description of exemplary embodiments of the invention have been presented for purposes of illustration and of description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and as practical applications of the invention to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.