US2008440A - Pinch clamp - Google Patents

Description

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INVENTOR 54W; yx a, L

KAMAMW E, H. FISHER PINCH CLAMP Filed April 19, 1933 mum "fof e July 16, 1935.

WITNESSES /Sz ac Patented July 16, 1935 UNITED STATES P ATENT OFFICE Fisher- Scientific Company, Pittsburgh, Pa., corporation of Pennsylvania,

Application April 19, 1933, Serial No. 666,855

2 Claims.

This invention relates to adjustable pinch clamps, such as are used with laboratory apparatus, for controlling the now o f fluid through exible tubing. Y

Pinch clamps that have been used heretofore have had a number of disadvantages, For instance, with all prior types known to me it has been difcult to maintain the pinch clamp in an upright position because the flexible tubing is not of sufficient rigidity to preventthe clamp from overturning. A major disadvantage of one type of pinch clamp has been the necessity for disconnecting the tubing in order to `remove vthe pinch clamp when the latter was no longer *de` sired. Pinch clamps constructed inl previous attempts to remedy the latter defect havebeen unsatisfactory, chiefly for mechanical reasons.

A major object of the present invention is to provide pinch clamps which are easily placedhcn and removed from the flexible tubingwitho'utdisturbing its connections, are rigidly constructed and can not open up in use, are of simple and in` expensive construction, and. which overcome or minimize other disadvantageous features clamps known heretofore. A Y

A particular object is to provide a clamp embodying the beneficial features just recited, which is also adapted to maintain itself upright `whenl in clamping position. n

A further object is to provide a clamp of the type described which is provided with simple means for. easily fastening it in xed position on a supporting structure.

The pinch clamp provided by the invention comprises a rectangular frame composed of top and bottom members, andside members which serve as guides for'the ends of a clamping bar movable toward and from the bottom member of the frame. The top, bottom and one side member are rigidly connected, for example in' the form of a C-frame, and the other side member is adapt'- ed to securely close the fourth side of the frame and to be moved relative thereto to open they side for insertion and withdrawal of the tubing to be clamped without the necessity of disturbing the connections of the tubing# The details of the invention will `be describe in connection with the accompanying drawing, in which Fig. l is a front elevation of a pinch clamp constructed in accordance with the pre- Yferred embodiment of the invention; Fig. v2 an end elevation of the clamp of Fig. 1; Fig. 3 a plan view of the pinch clamp, showing also in broken lines the use of the means shown in Figs. 5 and 6 for fixing the clamp to a support; Fig. 4 a view f the Vclamp comprises a rectangular frame l consisting of a top member 2, a base member 3 and side members Vll and 5. The members 2, 3 and 4 are rigidly connected to form a structure of substantiate-shape, the open end of which is closed by member 5 which is movably associated With top and bottom members 2 and 3. Member 5, which is in'the form of `a) cylindrical rod or post, is'provided atf its lower end with screwethreads 5a which cooperate with a threaded openingtin the.- extended end of base member 3, and it projects loosely through an opening 6 in the extended end of top member 2,its upper end being `provided with a thumb screw 1. l

Top member 2 is providedwith a substantially central boss` S having a screw-threaded opening through which extends an. adjusting screw Hi to the-lower end ofwhich is connected a clamping bar i i. he latter is provided at its right-hand endfas viewed in Fig'. l, with a projection or tongue l2slidably mounted .in a vertical groove I3, Fig; 4, in side "member Il. The other end of clampingbar I I is suitably curved to conform to post 5, whereby clamping bar l I is guided at both ends in its vertical movements in accordance with the adjustment of the-screw ill. Thus side member 5 may be heldA in fixed position to close the frame and provide a rigid side guide for the clamping bar, and it may be easily moved vertically. to open the `frame for slipping it over rubber tubing, by rotating it with thumb screw l to disengage threaded portion Ea, whereupon the post may be raised in the frame.

It is preferred itc construct post 5 so that it can not be taken out of the frame.` To this end threads 5a are rolled on one end of the post, which upsets/that end somewhat, as shown in the drawing. The postV is inserted upwardly through the screw threaded opening in the base and through opening 5, and thumbscrew 'i is then driven into place, this endof thepost having-been previously knurled for locking the thumb screw in place.

VIn the assembly of the clamp adjusting screw lil, it is inserted through the threaded opening in boss s and its lower end 'is inserted in a bore in the clamping bar. The reduced end portion of the adjusting screw is 'then upset, or riveted, as indicated at I6, Fig. 1, in the countersunk lowerl end of the bore, This provides for relative rotative movement between screw and bar, but prevents canting of the bar relative to the screw.

All of the pinch clamps known to me prior to the invention have tended to drop over onto their side when in clamping position on rubber and the like exible tubing. A feature of particular importance 'resides in my discovery of means for overcoming that disadvantageous feature. In allV prior clamps the cooperating faces of the clamping bar and basemember have been hat, or substantially so. I have discovered that by making those faces complementarily arcuate, i. e. one face concave and the other face convex, the clamp willV maintain itself upright when clamped on rubber tubing. .For ease of construction the base member is preferably givenY the concave clamping face, as shown at I4, Fig. 4, the adjacent cooperating clamping face I of bar I I being convex. The clamps provided by the invention preferably embody this feature, although it is applicable to laboratorypinch clamps of other constructions. Such shaping of these faces causes theY clamp ,toY remain `upright even with pure gum tubing. 1

In the use of the pinch clamp, post 5 may be disconnected by unscrewing it ,from base 3 where-u upon it may be Vvlifted upwardly to'permit the clamp being placed over the tubing to be controlled thereby, whereupon the post maybe returned to its illustrated position. Clamping bar I I mayV then be loweredV bymeans of adjusting screw IB to rirly clamp the tubing against base 3. TheV tubing is then caused/to assume such shape by reason of the curved clamping surfaces that it is suiiciently rigid to resist the overturning of the clamp from its-upright position, which is a feature of substantial advantage and novel iny this art. y

When it is desired to remove the pinch clamp from the tubing, clamping bar II is-released by means of the adjusting screw and the post I5 is disconnected and moved upward to open the side of the frame I whereupon the pinch,v clamp may be removed from the tubing without disturbing the connections of thelatter.

During theoperationof the pinch clamp, clamping bar I I is provided with suitable guiding means during its movements whereby its alignment with the cooperating base member is assured. Moving the detachable post 5 does not in anyr way interfere with the cooperative relationsV of the several parts but permits the easy insertion and. withdrawal of the tubing Vfrom the frame of the clamp.

It may be desirable under certain circumstances that the pinch clamp be rmly anchored in position, and I have provided simple and eiective means. for such purpose. Base 3 is provided at the bottom portion thereof with two lateral flanges or projections II, on opposite sides thereof. A plate member I3 is provided with aY slot IQ open at one end and of such size and shape as to permit `the plate to be passed Vover the end of base 3. Plate I3 is provided with recesses 20 on opposite sides thereofV for receiving the respective iianges I'I and thereby permitting the bottom of the plate and the bottom of the base 3 to be in alignment upon any suitable support, such as a laboratory bench or a wall. Plate I8 may then be fastened to :the support by means Y of screws 2|, for which holes 22 are provided, and

secure a new and beneficial result in that the' tubing is caused to be lof such form and shape as to resist the overturning of the pinch clamp. The foregoing and other advantages will be apparent to those skilled in the art relating to pinch clamps and similar devices.

According to the provisions of the patent statutes, I have explained the principle and construction of my inventionand have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim: f

l. A pinch clamp comprising a rigid C-'framav a movable side member for closing the open side of said frame extending 'through anY opening in the top member of the frame and having a screwthreaded connection to the base of the frame, said side member having at Aits upper end a knob of larger diameter thanV the opening in the top oi the frame `through which said member passes and having the screw-threads at its lower end of larger diameter than said opening, whereby to limit movement of said side member in the frame, and a clamping bar connected to a shaft making screw-threaded engagement with the top'of the frame for adjustablel movement of the clamping member toward andrfrom the bottom of the frame,

Ythe side of the frame and said movableV side memhaving a screw-threaded connection to said bot-V tom member, and a clampingqbar connected toa shaft making screw-threaded engagement with said top member for. adjustable'mo-vement of the be rigidly connected to a support for holding'the clamp upright.

Y EDWIN H. FISHER.

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