Roller clamp

Abstract

Roller clamp (1) for regulating the flow of a fluid through an elastically deformable tube, comprising a generally channel-shaped body (2) whose base (4) has a clamping surface (6a, 6b) with a longitudinal groove (7) having a cross-section that decreases from an initial end (7a) to a terminal end (7b). The longitudinal groove (7) has a stepped surface with steps (10) arranged transversely to the groove (7).

Description

[0001] "Roller Clamp"

[0002] ★ ★ ★

[0003] Field of the Invention

[0004] The present invention relates to roller clamps used in the medical field in particular, for regulating the flow of a fluid through an elastically deformable tube , for example in infusion / trans fusion devices .

[0005] More specifically, the invention relates to a roller clamp of the type comprising a body generally shaped as a channel having two side walls and a base wall along at least part of which a longitudinal groove is formed, said groove having a cross section that decreases from an initial end to a terminal end, with a bottom wall and lateral walls inclined outwardly from the bottom wall . A roller is rotatably supported by the side walls of the body and is longitudinally movable in a guided manner above the longitudinal groove to progressively clamp, in use , an elastical ly deformable tube inserted through the body between the longitudinal groove and the roller .

[0006] Background Art

[0007] Roller clamps of the type defined above are known, for example , from US 4 , 013 , 263 , US 4 , 662 , 599 , US 4 , 725 , 037 , EP 2105160 , EP 0985425 and EP 4169565 in the name of the same Applicant .

[0008] With the use of such roller clamps , the flow of fluid through the deformable tube is adj usted by progressively changing the longitudinal position of the roller along the clamping surface of the clamp body . The condition of minimum or zero flow corresponds to positioning the roller at the terminal end of the longitudinal groove formed along the clamping surface of the body, while the maximum flow condition corresponds to positioning the roller at the initial end of the longitudinal groove . This is evidently due to the fact that the cross-section of the tube clamped and compressed between the roller and the portions of the clamping surface of the body— between the longitudinal groove and the side walls of the body— defines a restricted passage or lumen for the fluid, whose width depends on the profile of the longitudinal groove : the smaller the cross-section of the longitudinal groove , the smaller the lumen section, and vice versa . In other words , roller positions progressively closer to the terminal end of the longitudinal groove correspond to a progres sively tighter clamping of the tube and consequently a more pronounced elastic deformation thereof .

[0009] Summary of the Invention

[0010] The obj ect of the present invention is to provide a roller clamp of the type speci fied above that ensures more controlled, ef ficient , and hence more precise operation .

[0011] Another obj ect of the invention is to provide a roller clamp of the type speci fied above with more finely adj ustable flow control .

[0012] A further obj ect of the invention is to provide a roller clamp of the type speci fied above in which the elastically deformable tube , typically made of plastic, is less subj ect during adj ustment to stresses and resulting " cold flow" phenomena due to its compression by the roller .

[0013] Yet another obj ect of the invention is to provide a roller clamp of the type specified above whose body can be manufactured using a smaller amount of material compared to known clamps . According to the invention, these and other obj ects are achieved by means of a roller clamp of the type speci fied above , the peculiar feature of which —as set out mainly in claim 1— is that the longitudinal groove of the clamp body has a stepped surface whose steps are arranged transversely to the groove .

[0014] In embodiments of the invention, the steps are arranged on the side walls of the longitudinal groove and descend from the initial end to the terminal end of the groove .

[0015] The steps may have equal longitudinal extension or di f ferent lengths . For example , groups of steps may have shorter longitudinal extension than other groups of steps .

[0016] Thanks to the stepped ( or toothed) configuration of the groove , several important functional advantages of the clamp are achieved, summari zed below .

[0017] First , a signi ficantly longer and therefore finer adj ustment length of the flow is obtained, together with improved gradualness , step by step— thus , in short , more continuous and precise regulation .

[0018] The tube inserted into the clamp body is , so to speak, hooked or gripped by the steps over which the roller moves : the tube is thereby more stably locked in place , avoiding the risk of unwanted slipping during adj ustment .

[0019] Thanks to the toothed side walls of the groove , the tube does not curl during adj ustment and relaxes between one tooth and the next . The compression exerted by the roller therefore generates less stress , thereby reducing "cold flow" ef fects , which further contributes to improving the stability of the regulation over time .

[0020] Brief Description of the Drawings Further features and advantages of the invention will become apparent from the following detailed description with reference to an embodiment shown in the accompanying drawings , provided solely by way of nonlimiting example , in which :

[0021] • Figure 1 is a perspective view of a roller clamp for medical use that represents one embodiment of the present invention,

[0022] • Figure 2 is a longitudinal sectional view of the roller clamp,

[0023] • Figure 3 is a top plan view of Figure 2 ,

[0024] • Figure 4 is a top view analogous to Figure 3 of the clamp body alone without the roller,

[0025] • Figure 5 is a front elevation view of the roller c 1 amp ,

[0026] • Figure 6 is an enlarged view of the detail indicated as A in Figure 5 ,

[0027] • Figures 7 and 8 are enlarged views of the details respectively indicated as C and B in Figure 4 .

[0028] Detailed Description of the Invention

[0029] With reference to the drawings , the numeral 1 denotes a roller clamp according to the invention, particularly intended for medical use to regulate the flow of an infusion, trans fusion, or similar liquid through an elastically deformable tube , not shown in the drawings .

[0030] The clamp 1 includes a body 2 and a wheel or knurled roller 3 ( Figures 1 , 2 , 3 , and 5 ) , both conveniently manufactured by plastic molding .

[0031] The body 2 has a general channel shape with a base 4 and two side walls 5a and 5b . A lower hollow proj ection 6 protrudes from the base 4 and has a known function .

[0032] The inner face of base 4 , i . e . the face directed inwardly of body 2 , will hereinafter be referred to as the clamping surface of the roller clamp 1 . Along most of this clamping surface , a longitudinal groove 7 is formed which defines , along body 2 of clamp 1 , a flow control region, and divides the clamping surface into two longitudinal clamping portions 6a and 6b, respectively adj acent to the side walls 5a and 5b .

[0033] The longitudinal groove 7 has an initial end 7a and a terminal end 7b, and its cross-section decreases from the initial end 7a to the terminal end 7b . This crosssection includes a bottom wall 8 arranged on base 4 of body 2 , and inclined side walls 9a and 9b, diverging from the bottom wall 8 toward the clamping surfaces 6a and 6b, respectively .

[0034] As shown more clearly in Figure 6 , both the depth and width of groove 7 progressively decrease from the initial end 7a to the terminal end 7b .

[0035] In accordance with the peculiar feature of the invention, the longitudinal groove 7 has a stepped or toothed surface : more precisely, its side walls 9a and 9b ( and optionally but not necessarily also the bottom wall 8 ) are formed with successive steps or teeth 10 descending from the initial end 7a toward the terminal end 7b of the groove 7 . The steps 10 are arranged transversely or orthogonally to the longitudinal groove 7 . The height di f ference between adj acent steps 10 and the groove width at the intersection points with the clamping surfaces 6a, 6b vary by a few hundredths of a millimeter, but considering the overall dimensions of clamp 1 ( its total length is about 5 cm) , they are still appreciable and ef fective .

[0036] The length of each step 10 , i . e . its longitudinal extension along clamp 1 , may vary depending on the total length of the clamp, which itsel f may vary depending on the applications thereof . As shown in Figures 7 and 8 ( scaled about 8 : 1 from the actual si ze of clamp 1 ) , one may provide larger groups of steps 10 with constant length of about 2 mm and smaller groups of steps of about 1 . 7 mm . The longer steps may be positioned toward the initial end 7a of groove 7 and the shorter steps may be provided toward the terminal end 7b of groove 7 . Other configurations may also be used as an alternative to those disclosed herein .

[0037] In the flow control region, the side walls 5a and 5b each have internal slots 11 that extend substantially parallel to the clamping surfaces 6a and 6b . These two slots 11 form longitudinal guides in which two axial pins 12 ( see Figure 5 ) proj ecting from opposite sides of roller 3 are freely rotatably and slidably engaged .

[0038] The roller 3 is therefore longitudinally slidable and rotatable along the guides 11 , which, together with groove 7 and clamping surfaces 6a and 6b, define the aforementioned flow control region .

[0039] In use , an elastically deformable tube (not shown) , normally made of thermoplastic material , is inserted into the body 2 through its front end corresponding to the initial end 7a of groove 7 , between clamping surfaces 6a, 6b and roller 3 . When roller 3 is positioned in front of the initial end 7a of the groove 7 , the tube remains substantially undeformed, so no flow regulation of the liquid inside it occurs . To regulate the flow, roller 3 must be moved to the initial end 7a and then toward the terminal end 7b of groove 7 , for example in the area shown in Figures 2 and 3 . In this way, the tube is progressively elastically deformed between roller 3 and the clamping surfaces 6a, 6b, gradually reducing the fluid passage through a lumen whose si ze is directly proportional to the cross-section of groove 7 . In other words , the si ze of the lumen, and hence the flow rate of the liquid across the tubing, is greater when the roller 3 is positioned in correspondence of or near to the initial end 7a of the longitudinal groove 7 , and reduces progressively as the roller 3 is moved little by little towards the terminal end 7b .

[0040] The presence of the transverse steps 10 along groove 7 , particularly on its side walls 9a, 9b, produces one or more of the following advantages in terms o f the functional ef fectiveness of clamp 1 :

[0041] • A substantial extension of the ef fective flow regulation range , which is typically limited to j ust 2-3 mm in conventional roller clamps . This extension allows for finer adj ustment and hence signi ficantly improved precision, along with more gradual deformation of the tube .

[0042] • More ef fective retention of the tube inside the clamp body : the tube is gripped and held more securely during adj ustment of roller 3 , avoiding unwanted slippage .

[0043] • During regulation, the tube does not curl and is able to relax between one tooth and another, which reduces stress on the tube compressed by roller 3 , and thereby reduces "cold flow" phenomena . This further enhances the precision and long-term stability of flow regulation .

[0044] • A noticeable reduction in the amount of plastic material needed to manufacture clamp body 2 .

[0045] These advantageous ef fects have been veri fied experimentally by the Applicant through comparative testing of the clamp according to the invention versus conventional roller clamps .

[0046] Naturally, the construction details and embodiments may vary widely from what is described and illustrated, without thereby departing from the scope of the invention as defined in the following claims .

Claims

CLAIMS1. Roller clamp (1) for regulating the flow of a fluid through an elastically deformable tube, comprising a generally channel-shaped body (2) having two side walls (5a, 5b) and a base (4) , along at least part of which a longitudinal groove (7) is formed with a bottom wall (8) , inclined lateral walls (9a, 9b) diverging from said bottom wall (8) , and an initial end (7a) and a terminal end (7b) , said longitudinal groove (7) having a crosssection that decreases from the initial end (7a) toward the terminal end (7b) , and a roller (3) rotatably supported by said side walls (5a, 5b) of the body (2) and longitudinally movable in a guided manner over the longitudinal groove (7) to progressively clamp, in use, the elastically deformable tube inserted through the body (2) between said groove (7) and said roller (3) , characterized in that said groove (7) has a stepped surface with steps (10) arranged transversely to the longitudinal groove (7) .

2. Roller clamp (1) according to claim 1, characterized in that the steps (10) are formed on the side walls (9a, 9b) of the longitudinal groove (7) .

3. Roller clamp (1) according to claim 1 or 2, characterized in that the steps (10) descend from the initial end (7a) toward the terminal end (7b) of the longitudinal groove (7) .

4. Roller clamp (1) according to any one of the preceding claims, characterized in that said steps (10) have equal longitudinal extension.

5. Roll er clamp (1) according to any one of claims 1 to 3, characterized in that said steps (10) have different longitudinal extensions.

6. Roller clamp (1) according to claim 5, characterized in that groups of said steps (10) have a shorter longitudinal extension than the longitudinal extension of other groups of steps (10) .

7. Roller clamp (1) according to any one of the preceding claims, characterized in that said steps (10) are also arranged on the bottom wall (8) of said longitudinal groove (7) .

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