Abstract:
An improved mounting clamp adapted to simultaneously secure flat ribbon cables and a number of fluid tubes to a surface and having a locking feature to facilitate assembly and release.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a lockable clamp for simultaneously securing a number of liquid carrying tubes and at least one ribbon electrical cable to a surface. 
     BACKGROUND OF THE INVENTION 
     Various types of analytical tests related to patient diagnosis and therapy can be performed by analysis of a liquid sample taken from a patient&#39;s infections, bodily fluids or abscesses. These assays are typically conducted with automated clinical analyzers onto which liquid patient samples have been loaded. The analyzer extracts liquid sample from a container and combines the sample with various reagents in special reaction cuvettes. Usually the sample-reagent solution is incubated or otherwise processed before being analyzed. Analytical measurements are performed using a beam of interrogating radiation interacting with the sample-reagent combination to generate absorption readings or the like. The readings allow determination of end-point or rate values from which an amount of analyte related to the health of the patient may be determined using well-known calibration techniques. 
     Within such analyzers, a large number of liquid sample and reagent aspiration/dispensing probes are usually employed in order to extract incoming sample from a container, dispense aliquot portions of said sample into an aliquot array, to aspirate aliquot samples from the array and dispense aliquot samples into a reaction cuvette, and/or to extract reaction reagents from a container and directly dispense aspirated reagents into a reaction cuvette. In addition, within such analyzers, a very large number of electrical cables are interconnected between the various electromechanical controlling and controlled devices. For space-saving reasons, a popular electrical cable is shaped like a flat ribbon and is formed of a number of electrical conductors covered by an insulator and placed side-by-side. Ribbon electrical cables are frequently utilized to direct electrical signals between stationary printed circuit boards and electromechanical devices that are translated horizontally and vertically for millions of cycles. In a typical static application a latch may be sufficient to retain the cable securely. However, in applications in which substantial and/or sustained movement is encountered like described, latches are usually found to be inadequate over periods of sustained use. Thus, a need exists for a retaining device which secures the cable securely irrespective of substantial sustained movement. 
     In order to minimize impact upon patients as well as to decrease the costs of clinical assays, the volumes of liquid sample aliquots and reagents are increasingly made smaller, in the range of about 1 microliter to five microliters; therefore, the pumping systems associated with sample and reagent aspiration and dispensing probes must be capable of handling precisely known and controlled liquid volumes. Almost all sample and reagent aspiration/dispensing probes are mounted on translatable arms having both horizontal and vertical motion in order to translate probes between locations as well as to raise and lower probes into and out of containers. Consequently, a popular practice is to attach a probe to a pumping system using flexible tubing; furthermore, to reduce pumping volume uncertainties, the tubing is filled with an inert liquid, as opposed to air, between the pumping system and the probe. The tubing is also generally secured on and between stationary and/or moving parts using a guide with circular dimensions. Traditionally, clamps have been available to secure only an electrical cable or to secure only liquid tubing. In addition to requiring the assembly of a large number of tubing or ribbon clamps, not all clamps are provided with locking features allowing easy assembly and release. It has also been discovered, however, that the tubing must be precisely placed and maintained along the central radius of curvature of such a guide in order to prevent a “peristaltic-type” pumping action of the fluid within the tube as the curved section of tubing moves. If the tubing falls to the inside of the guide, the tubing is slightly compressed; likewise, if the tubing falls to the outside of the guide, the tubing is slightly stretched. Both actions cause a change of volume of fluid inside the curved portion and a pumping action is created as the probe is translated. This false pumping is in addition to the controlled pumping, thereby adversely affecting the accuracy of the aspirated or dispensed sample/reagent liquid. 
     SUMMARY OF THE INVENTION 
     The present invention meets the separate needs for securing flat cables and round tubes by providing a single clamp adapted to simultaneously secure at least one flat ribbon electrical cable and a number of fluid tubes to a surface and having a locking feature to facilitate assembly and release. Such a device reduces both the total number of clamps required and their associated costs. In a particular embodiment of such a cable-tubing clamp, the clamp is used at both ends of a flexible router, one cable-tubing clamp mounted proximate a stable electrical power and control source, the other end located proximate a moveable liquid aspiration/dispensing probe. During assembly, the clamp is opened to expose grooves for securely inserting round liquid tubes, a flat ribbon cable is applied over the tubes and a locking clasp is lowered over the cable and lip-locked in place. A tab on the lip-lock facilitates entry of the lip-lock during assembly and also prevents the locking tab from being pulled sideways by forces acting on either the tubes or the cable(s). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be more fully understood from the following detailed description thereof taken in connection with the accompanying drawings which form a part of this application and in which: 
         FIG. 1  is a right side perspective assembly view of the tube and cable clamp of the present invention attached to a frame member and shown clamping three tubes and a flat electrical ribbon cable; 
         FIG. 2  is a left perspective view of the tube and cable clamp of  FIG. 1  in an opened position; 
         FIG. 3  is a right perspective view of the tube and cable clamp of  FIG. 1  in an opened position; 
         FIG. 4  is a front elevation view of the tube and cable clamp of  FIG. 1  in an opened position; 
         FIG. 4A  is a front elevation view of the tube and cable clamp of  FIG. 1  in a closed position; 
         FIG. 5  is a side elevation view of the tube and cable clamp of  FIG. 1  in an opened position; 
         FIG. 6  is a top view of the tube and cable clamp of  FIG. 1 ; and, 
         FIG. 7  is a perspective assembly view of the tube and cable clamp of  FIG. 1  attached to a frame member and shown clamping three tubes and a flat electrical ribbon cable. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective assembly view of the tube and cable clamp  10  of the present invention attached to a frame member  12  and shown clamping three liquid carrying tubes  14  and a flat electrical ribbon cable  16 . In an exemplary embodiment, liquid tubes  14  form an integral portion of aspirators like described above and ribbon cable  16  comprises a number of individual electrical conductors covered by an insulator and placed side-by-side, the connectors carrying electrical signals between an aspirator transport device, interface devices and a control computer. Tube and cable clamp  10  is provided with a number of unique features described hereinafter in order to facilitate assembly and secure clamping of tubes  14  and cable  16 . 
       FIG. 2  is a left front perspective view of the tube and cable clamp  10  of  FIG. 1  showing clamp  10  in an opened position, clamp  10  having a compressible tube carrying center member  18  with a number of parallel open tube groves  20  formed in the top portion of tube carrying center member  18 . Three groves are illustrated, however, it is obvious to an artesian that center member  18  and groves  20  may be sized in order to secure any number of tubes  14  that typically carry a liquid but may also carry a vacuum and/or a pressurized gas.  FIG. 3  is a right front perspective view of the tube and cable clamp  10  of  FIG. 1  showing clamp  10  having a generally planar base  22  having front, right side and left side and back portions and a right side wall  24  vertically extending from said right portion and an optional positioning hook  26  (best seen in  FIG. 5 ) extending from said back portion. Taken with  FIG. 2 ,  FIG. 3  also shows an important feature of the present invention as being a clasp member  28  flexibly formed integral with right side wall  24  by means of a reduced wall portion  30 , clasp member  28  being moveable towards tube carrying center  18  so as to close parallel open tube groves  20  thereby to secure tubes  14  and ribbon cable  16  between the top surface  18 T of tube carrying center  18  and clasp member  28  (as seen in  FIG. 4A ). The tube carrying center member  18  preferably comprises a compressible thermoplastic resin material selected so ribbon  16  cable can be clamped between the top surface of the tube carrying center  18 T and the clasp member  28  when a foot portion  36  engages an inner lip portion  38  of the left side wall  40  as described hereinafter. 
     A reinforcing ledge  29  is formed as an integral part of clasp member  28  in order to provide extra strengthening when clasp  28  is closed over tubes  14  and ribbon cable  16 . Similarly, a reinforcing brace  25  is formed as an integral part of side wall  24  in order to provide extra rigidity in supporting clasp member  28 . Another important feature of the present invention is a locking member  32  flexibly formed integral with clasp member  28 , locking member  32  having a foot portion  36  and being moveable so as to engage an inner lip portion  38  of a left side wall  40  extending upwardly from base  22 . A guide finger  42  is formed at the rear of left side wall  40  to facilitate locking of foot portion  36  and lip portion  38  as described hereinafter. An open tab  44  extends frontwardly from base  22  to facilitate attachment of clamp  10  as described hereinafter. 
       FIG. 4  is a front elevation view of tube and cable clamp  10  with clasp member  28  in an open position that exposes tube groves  20  so that one of more liquid carrying tubes  14  may be easily inserted therein. Tube carrying center  18  is illustrated as comprising a pair of opposed truncated-S-shaped legs  19  integrally formed with base  22  and, in combination with a corrugated top member  23 , defining an open center portion  21 . Tube groves  20  define the corrugations in corrugated top member  23 . Clamp  10  is made from a deformable plastic described hereinafter with a modulus selected such that tube carrying center  18  may be slightly compressed by clasp member  28  securing tubes  14  and cable  16  when in a closed position like seen in  FIG. 4A . 
       FIG. 4A  is a front elevation view of the tube and cable clamp of  FIG. 1  in a closed position in which three tubes  14  have been placed within tube groves  20  and a flat electrical cable  16  has been placed over the top of corrugated top member  23 . The illustration of a single cable  16  is not intended to be limiting, as is obvious to an artesian, more than one such cable  16  may be placed over the top of corrugated top member  23  with simple adjustments of the dimensions of top member  23  and clasp member  28 . Clasp member  28  is illustrated in a closed position securing tubes  14  and cable  16  and locking member  32  has been placed in a locked position in which foot portion  36  is trapped beneath inner lip portion  38  of left side wall  40 . During the process of placing locking member  32  in a locked position, finger portion  42  of left side wall  40  so that foot portion  36  is easily slipped beneath inner lip portion  38 . Finger  42 , in conjunction with wall  40 , acts to prevent foot  36  from being pulled sideways by external forces applied by the tubes  14  or cable  16 . Resistance to the compression of tube carrying center  18  acts to maintain foot portion  36  of locking member  32  engaged underneath inner lip portion  38 . 
       FIG. 5  is a side elevation view of the tube and cable clamp of  FIG. 1  illustrating positioning hook  26  as being integral with base  22  extending frontward from a depending ledge  27 .  FIG. 6  is a top view of the tube and cable clamp of  FIG. 1  and best illustrates opening  46  in tab  44  through which rivulet  47  attaches clamp  10  to an appropriate surface.  FIG. 7  is a perspective assembly view of clamp  10  attached to a frame member  48  and thereon thereto by positioning hook  26  and secured thereto by a screw or rivulet  47  inserted though opening  46  in tab  44 . Note that even though clamp  10  is “inverted”, tubes  14  and cable  16  are secured by clasp member  28  clamping tubes  14  and cable  16  when in a closed position like seen in  FIG. 4A . 
     Clamp  10  may be molded from any of a number of thermoplastic resin materials, including polyolefins and polyethylene, preferred because of lifetime in flex operations. Clamp  10  can also be comprised of a combination of such resins. Preferably however, because of the necessity for precise dimensioning, an engineering plastic like acrylonitrile butadiene styrene, ABS, a copolymer of acrylonitrile, butadiene, and styrene may be advantageously employed. ABS plastics generally possess medium strength and performance and medium cost and are often used as the cost and performance dividing line between standard plastics (PVC, polyethylene, polystyrene, etc.) and engineering plastics (nylon, acetal, etc.). 
     It should be readily appreciated by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. For example, as mentioned, the dimensions of top member  23  and clasp member  28  can be adjusted to accommodate more than one electrical cable  16  and/or center member  18  and groves  20  may be sized in order to secure any number of tubes  14 . Accordingly, while the present invention has been described herein in detail in relation to specific embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.