US2798687A - Automatic volume control device - Google Patents

Description

y 1957 D. A. HAMILTON 2,798,687

AUTOMATIC VOLUME CONTROL DEVICE Filed Jan. 18, 1954 2 Sheets-Sheet l Dav/04p A A pM/L raw.

v INVENTOR.

y 1957. D. A. HAMILTON 2,798,687. AUTOMATIC VOLUME CONTROL DEVICE Filed Jan. 18, 1954 2 Sheets-Sheet 2 flax/440 flaw/4 mv. INVENTOR' MA/r5 2,798,687 AUTOMATIC VOLUME CONTROL DEVICE Donald A. Hamilton, Burbank, Caiifi, assignor to Don Baxter, The, Glendale, Califi, a corporation of Nevada Application .lanuary 18, 1954, Serial No. 434,759 Claims. (Cl. 24958) This invention relates to a device for automatically shutting off the flow of fluid through a collapsible tubing, and refers more particularly to a device for automatically shutting oif the tubing after the flow of a predetermined desired volume through the tubing. The device is particularly valuable in connection with plastic containers for drawing blood.

Where a plastic container is employed for drawing blood, dificulty is experienced in drawing an accurate volume. The plastic containers being elastic can stretch enough to permit double the desired volume. it the plastic container is made small enough so that in its extended position it holds just the desired volume, the drawing time is too slow. Devices presently used with plastic containers are all costly, have possibilities of error, have no shutoff feature, and require constant supervision of an attendant to prevent overbleeding of the donor.

It is a general object of the present invention to provide a device which will permit proper filling of plastic containers and automatically shut off the How through a tubing to a plastic container when a predetermined volume has been withdrawn. The device of the present invention is thus intended to eliminate the necessity of an attendant being in constant supervision of the donor from whom blood is being withdrawn, and intended also to eliminate the cost and the possibility of errors attendant with present devices.

The device of the present invention is substantially a spring balance for suspending a plastic container during the operation of filling the same through a collapsible tubing. The spring balance of the present invention in cludes a trigger which is tripped whenever the suspended load equals a predetermined value, and said trigger is associated with means for clamping or collapsing the tubing to shut off the flow of fluid to the container. In the preferred form of the invention the device is so simple that it is constructed of a single piece of spring wire.

The device of the present invention, together with additional advantages of the invention, will be readily apparent from the following description of the preferred form or example of the invention, the description being given in connection with the accompanying drawings, in

which,

Figure 1 is a perspective elevation of the device of the present invention with a collapsible tube in place, the device being shown before the trigger of the device is tripped.

Figure 2 is a similar view after the device has been tripped to collapse the tubing and shut off the flow therethrough.

. Figure 3 is a perspective view of a modified form of the invention, the device being shown before the trigger of the device is tripped; and

Figure 4 is a perspective view of a further modified form of the present invention, the device being shown before the trigger is tripped.

Referring to the drawings, as illustrated the device preferably comprises a single piece of spring wire. One end of the wire is bent to provide a means on the device by which the device may be suspended from a support. The most simple form of such means is an open hook portion 2. Below the hook portion 2 the wire is bent horizontally, as indicated at 3, and curved back to provide a shoulder 4, or a catch which forms one part of Patented July 9, 1957 the trigger of the device. From the shoulder 4 the wire is bent preferably extending some distance to the otherside of the hook portion 2 in order to provide a loop 5.- The loop 5 provides a flexible or spring element in the device interconnecting the hook portion 2 with the bot-- tom suspending hook means hereafter described by means; of which it will permit an extension of the distance between said elements with increase in load. The loop 5 also provides a counterbalance portion which furnishes a means by which the device will hang substantially vertically even before it is loaded by the attachment to the device of a plastic container. This facilitates the operation of setting up the apparatus with its associated device. The wire from the counterbalance portion 5 is bent back to substantial alignment with the hook portion 2 and then extends downwardly therefrom as indicated at 6.

At the lower end of the wire portion 6 the wire is preferably bent out in substantially horizontal direction at nearly right angles to both wires 6 and 5 to provide a shoulder member. The shoulder member 7 is to assist in stiffening the hook element of the device as hereafter described, as well as to provide means for stiifening the clamping and shutoff elements. The wire is then bent somewhat inwardly and extends upwardly at a slant, as indicated at 8, the wire 8 forming one of two substantially parallel wire portions which serve as a portion of the tubing shutoff of the device. At its upper end the wire 8 is preferably bent in a horizontal direction, as indicated at 9, and then returned to form the slanting wire 10, which is the other member of the pair of slanting, substantially parallel wire members which provide a part of the whole shutoff element of the device. The wire 10 at its lower end passes around and in contact with the shoulder 7 and then is bent outwardly to form the supporting hook element 12, the wire being doubled back throughout the hook element 12, and then extends on the opposite side of the wire forming shoulder 7 upwardly, as indicated at 14. In the tripped position, as shown in Figure 2, this wire extends upwardly at a slant between the two wire portions 8 and 10. The inherent tension at which the wire is formed normally tends to retain the portion 14 in the position shown in Figure 2, but when it is desired it may be flexed until it is set over the shoulder 4, as indicated in Figure 1, in which case a V-shaped slot is provided between the member 14 and the wire portions 8 and 10. It is in this slot that the flexible tubing 15, which is to be closed by the device, normally is positioned.

When first set in the cocked position with the member 14 engaging the shoulder 4, the end of the wire portion 14 extends somewhat above its contact point with the shoulder 4. The distance that it extends above is one of the characteristics which determine the loads at which the device will trip. In use when a container is suspended on the hook portion 12 and progressively filled by the flow of fluid through the tubing 15, the weight of the plastic container and its contents causes a stretching of the wire device between the hook portion 2 and hook element 12, the curved end 17 of the portion 5 acting somewhat as a pivot point so that gradually the upper end of the wire portion 14 is progressively lowered with respect to the shoulder 4 until it snaps free from said shoulder. At that instant the tension of the wire member 14 causes the same to collapse the flexible tubing 15 between itself and the two wire members 8 and 10. The load on the device at which this trigger action will take by varying the length of the member 1 In practice this device is shown readily able to control the filling of a plastic container, such as employed in drawplace is adjustable Figure 3, I have shown a form of the invention in which the device is made partly from spring wire and partly from sheet metal. As illustrated the wire portion of the device at its upper end comprises a suspension section.

or hook 2a. It is then bent horizontally, as indicated at 3a, and bent horizontally at right angles thereto, asindicated at 4a, thereby forming a shoulder which forms one.

the shoulder provided by the portion 4a but onincreaseof load the angle between portions 5a and 6a increases until the free end of the portion 14a is released from the shoulder 4a.

The tubing clamp or shutoff member of this form of the invention is provided in part by the upwardly rising portion 14a of the wire member and by a piece of sheet metal which consists of a strapped portion 7a provided with two openings 18 and 19.by which it is threaded on the Wire member, the strapped portion 7a being bent slightly as indicated at 20.

At the lower end of the portion 7a the center portion of the sheet metal is cut to form a tongue which extends downward, as indicated at 12a, to form av hook whichin practice serves to suspend the device which is to receive the blood from the tubing 15a. There is also provided two spaced-apart members 8a and 10a slanting upwardly at an angle and parallel thereto which form parts of the tubing shutoff of the device.

In use of this form of the invention the device is suspended from the portion 2a of the wire and the container suspended on the hook portion 12a of the sheet metal member. The tubing 15a (which leads to the receiver) lies across the portions 8a and 10a and between them and the wire portion 14a. As the container is filled the loadv increases until the wire 14a disengages downwardly from the shoulder 4a, the inherent tension on the wire tending to snap the portion 14a between the sheet metal members 8a and 10a, thereby clamping or collapsing the tubing to shut ed the flow.

Now referring more particularly to the form of the in-. vention shown in Figure 4 in this case I have again indicated the invention as formed of a single piece of metal, in this case spring sheet metal rather than spring wire as in the first form of the invention. In Figure 4 the entire device is formedof a single length of originally fiat sheet metal, which is cut and bent as indicated in the drawing. As illustrated in the drawing there is the hook portion 2b below which a portion is cutout, as indicated, to form the tongue 4b, which is hooked at its end to form part of the. trigger mechanism. There is also the horizontally bent portion 5b which extends to the bend 17b, from which the device extends downwardly, as indicated at 6b, and at the lower end terminates at one or more hook portions 12b, which as indicated may be used to suspend a container 21. Two parallel tongues 8b and 10!; extend upwardly and form two elements of the tubing clamp or shutofi. Between these elements a further portion of the sheet metal is cut out to provide the trigger member 14b which, when released, is under tension so as to normally pass between the two portions 8b and 10b but is, adapted to engage the hook end of the portion 4b in the cocked position.

With this form of the invention the, tubing 1515 which is carrying fluid to the receptacdle 21 is laid, over the portions 8b and 10b and between these and thetrigger element 14b. As theload in the receptacle-Z1 increases thetrigger 14b is released from th e-hookon portion 4b and snaps toward the trigger elements 817- and 10b clamping the tubing 15b to shut oi the flow.

This inventionis of the scope set-forth intheappended claims.

I claim:

1. An automatic shutoff device for a tubing passing liquid to a container suspended by the device, which comprises two attachment elements on the device, one for attaching a container to the device and the other for mounting the device, the device including means for yieldingly holding the attaching elements together permitting the distance between the elements to increase with increase of the suspended load, and tubing clamping means normally retained in the open position and releasable at a predetermined load to move to a position cutting ofi flow through said tubing.

2. An automatic shutoff device for a tubing passing liquid to a container suspended by the device, which comprises a member at one end of the device for attaching a container to the device, a member at the other end of the device by which the device may be supported, a spring connection between said members by means of which the distance between said members increases with the increase of the suspended load, and a tubing clamping element normally retained in the open position and actuated by a predetermined increase in separation between said members to move to engage said tubing and cut otf flow therethrough.

3. An automatic shutofl device for a tubing passing liquid to a container suspended by said device, said device comprising a piece of spring wire shaped at the upper end to provide an element for support of the device, said wire being shaped at the lower end to provide a member for suspending a container, the wire between said members providing a flexible spring connection between said members which will permit the separation between the same to, progressively increase with increasing load, the wire also being shaped to provide a tubing shutoff clamp, and said tubing shutofi clamp being normally retained in an open position being actuated at a predetermined separation of said members at the closed position.

4. An automatic shutofi device for a tubing passing liquid to a container suspended by said device, which comprises a piece of spring wire shaped at its upper end to provide a suspension hook, below said suspension hook said wire forming a shoulder and a resilient expansion element, below said element the wire being shaped to provide a V-type tubing clamp, and at the lower end the wire being formed to provide a hook for suspending a container from the device, one part of the tubing clamp being normally in engagement with said shoulder to retain the tubing clamp in the open position and being disengageable from the tubing clamp for spring movement to closed position at a predetermined load.

5. An automatic shutoff device for a tubing passing liquid to a container suspended by said device, which comprises a member for suspension of the device at one end, a member for suspension of a load at the other end, spring means interconnecting said members to permit an increased separation of the members with increased load, a pair of parallel spaced-apart upwardly rising tubing clamping members, a trigger member movable therebetween in tubing shutoff operation and movable to a cocked position, means forming a shoulder for normally holding the trigger member in cocked position, the trigger member being supported adjacent the lower suspension element, and adapted to be released from said, shoulder on-increase of separation between said suspension elements.

References Cited in the file of this patent UNITED STATES PATENTS 576,685 Newcomb Feb. 9, l897 606,559 Knottnerus June 8, 1898 733,290 Simon July 7, 1903 1,495,724: Blake May23, 1924 2,610,019 Beall Sept. 9, 1952

Images