US2572686A - Automatic closure for valve-bag valves - Google Patents

Description

Oct. 23, 1951 s, ANDRE 2,572,686

AUTOMATIC CLOSURE FOR VALVE-BAG VALVES Filed May 24, 1946 Per" Augusi SDL'LLTE ATLCfTE Patented Oct. 23, 1951 AUTOMATIC CLOSURE FOR VALVE-BAG VALVES Per August Sture Andr, Stromsnasbruk, Sweden Application May 24, 1946, Serial No. 672,096

I In Sweden January 3, 1946 Claims. 1

This invention relates to automatic closures for valve-bag valves; and it consists of a device for automatically closing the valves of valve-bags of the type employing a dispensing sleeve or envelope of paper or the like flattened horizontally to form upper and lower sheets or walls, said sleeve being passed between and sealed to the flaps at the end of a bag and having a discharge mouth inside the bag, said closure comprising a folding line close to the mouth of said sleeve, an arcuate leaf spring mounted on the upper wall at the mouth of said sleeve on the forward side of saidfolding line, said Spring being usually secured to the top of said wall by means of a reinforcing strip sealed over said spring, a second arcuate leaf spring mounted on the lower wall of said sleeve to the rear of said folding line, said second spring being usually, secured to the bottom of said wall by means of a second reinforcing strip, the lower wall being advantageously partly cut away back to said folding line to produce a protruding upper lip and a receding lower lip with strengthening web sections joining the ends of said lips, said springs having opposite curvatures and both springs preferably being convex towards the axis of the sleeve when the latter is unfolded and the rear spring being advantageously convex upwardly, whereby said springs tend automatically to spring into concentric position with the first spring beneath the second and with the upper lip folded downwardly and inwardly along said folding line thereby clos ing the valve mouth; all as more fully hereinafter set forth and as claimed.

Paper bags having filling valves have been known for many years. In most of these the flaps at one end of the bag have been left unsealed for the insertion therebetween of a filling tube. Various ways have been devised for sealing the flaps after the filling operation and withdrawal of the filling tube. All of these have required a special sealing operation and many have required the use of a special tool to produce closure of the valve. These operations have all been time consuming and ineflicient.

I have discovered a surprisingly simple way of automatically closing the valves of valve-bags which entirely eliminates the necessity for a separate sealing operation. I make use of the rather surprising phenomenon that, when a folding line is provided close to the end of a flattened filling sleeve or envelope and an arcuate leaf spring is mounted on either side of the folding line, one on top and the other on the bottom wall of the sleeve, with their curvatures opposite,

these springs'tend to spring into concentric position one over the other thus causing the end of the sleeve automatically to fold over. In the present invention the arcuate leaf springs are mounted at the discharge opening of a filling sleeve of paper or fabric material which is inserted between the flaps at the end of a bag and these springs are mounted at the mouth of the discharge opening preferably in such fashion that they tend to fold the end of the sleeve downwardly and inwardly thus sealing the valve. The valve sleeve itself is cemented to the flaps thus making a tight seal at this point. When the filling tube is inserted through the sleeve into the bag it forces the valve open but, when withdrawn, the end of the sleeve snaps shut automatically.

In order to make the sleeve end fold downwardly it is necessary that the forward spring be mounted on the upper wall of the sleeve and that the rear spring be mounted on the lower wall. I have also found it highly advantageous to have the lower wall of the valve sleeve cut away at least partly back to the folding line, so that there are formed, in effect, an upper protruding lip and a lower receding lip at the mouth of the valve. The fold then takes place along a single thickness of material. A more complete fold results and there is no tendency for the valve to remain partly open.

My invention can be described more accurately by reference to the accompanying drawing which shows, more or less diagrammatically, several views of my automatic valve-bag closure. In this showing,

Fig. 1 is a perspective view of a bag fitted with one of my valves with a filling tube in filling position, part of the bag being cut away to show details,

Fig. 2 is a bottom view of the discharge end of the valve sleeve with closing flap in open position,

Fig. 3 is a similar view with closing flap in closed position,

Fig. 4 is a vertical cross section through the discharge end of the valve in open position, taken along the line 4-4 of Fig. 2,

Fig. 5 is a plan view of the discharge end of the valve with closing flap in open position,

Fig. 6 is a similar view with the closing flap in closed position,

Fig. '7 is a front end view of the valve with filling tube in position,

Fig. 8 is a perspective view of the front end with the valve closed by the closing flap, while I Fig. 9 shows several different ways of attaching the valve springs of my invention to the discharge opening of the valve sleeve.

In the several views like parts are designated by like reference numerals. Referring first to Fig. 1, anend of a bag I is shown, equipped with one of my filling valves shown generally at 2. The bag is a conventional paper or fabric bag and formed with a diamond shaped end having the usual end flaps 3 and 4 and superposed side fiaps 5 and B which, as usual, are sealed where they overlap. The side fiaps are also sealed to end flap 3 but not to 4 and my valve is inserted in the opening between flap 4 and side flaps 5 and 6. The valve consists of an envelope or flattened sleeve 8 of paper or fabric which is tightly sealed in position between flap 4 and flaps 5 and 6.

The sleeve extends beyond the end of flap 4 and 1 into the interior of the bag, as shown in Fig. 1 and the filling tube 1, during filling of the bag, is sl p ed thr gh t e sle ve into the bag- The inn r end of .my valv sleeve is provided Withm ns f r au m i lly losin it by folding over an end section thereof. The inner jsleeve adjacent its discharge opening is formed with a forward reinforced transverse strip H) and a rearward reinforced transverse strip II, these strips being usually constructed of heavy paper and separated by a folding section 12. The reinforcing strips are sealed to the top and bottom of the valve sleeve and serve to retain arcuate spring strips or leaves l3 and I4, respectively; see Fig. 4:. These springs are preferably made of spring steel and they have a curvature which advantageously ranges from about the curvature of the valve sleeve when open to about one-half of this curvature. When these springs are attached to the top and bottom of the valve sleeve, as in invention, and separated by a folding section, the two springs tend automatically to spring into concentric position one over the other as shown in Figs. 3, 6 and 8, thus closing the end of the sleeve. There is, of course, some tendency for these springs to spring into concentric position with the forward spring on top of the rearward spring but this tendency is prevented by the top of the bag. And, ifv the end of the valve sleeve is pre-folded downwardly before bein inserted in the bag, it will invariably fold in this direction in service.

In Fig. 9 the reinforcing strips l0 and II and the springs i3 and I 4 are shown diagrammatically in various possible positions within this invention, the reinforcing strips being indicated by dotted lines. It will be understood that the springs are always positioned between the reinforcing strips IO and I I and the valve sleeve (not shown). The reinforcing strips are sealed to the sleeve over the springs and serve to retain the latter. The sleeve in these modifications is always adjacent the springs. In modifications A and E, for example, the springs are mounted outside the sleeves, in modifications B and F the springs are inside, while in the remaining figures one spring is inside and the other is outside. In each instance the springs have opposite curvatures.

As mentioned previously, I have found that in order to force spring i3 to fold the outer end or mouth of the sleeve downwardly over the inner spring, the outer reinforcing strip H3 and spring I'3'must be attached to the top of the valve sleeve and the inner spring must be attached to the bottom of the sleeve. These springs must also be attached so that they have opposite curvatures when the sleeve is'unfolded, in which position they tend to flatten the sleeve. I have also found it advantageous to have the inner spring secured to the bottom of the sleeve in such position that it is convex upwardly as in modifications A to D of Fig. 9. In this position the spring conforms somewhat in shape to the curved end of the bag and the ends of the reinforcing strips, when in closed position, are turned downwardly so that they do not engage the sleeve, in which position they might tend to wear holes in the sleeve. It is also advantageous to have the reinforcing strip on the concave side of the spring so that the sharp ends of the springs bear against the reinforcement rather than the sleeve. If these principles are applied to the modifications shown in Fig. 9, it will be seen that these modifications can be arranged in the following order of preference, namely AD-C- BF-GH--E. Modification E is the poorest since the springs, in the closed position of the bag, do not conform to the shape of the bag top and the ends ofboth springs tend to puncture the valve sleeve.

As stated previously, the springs 13 and 44, when arranged as in any of modifications A to H, tend automatically to fold the end of the sleeve downwardly along the folding section 12 so that the two springs are substantially concentric, spring I3 being beneath spring 14, in the position shown from below in Fig. 3, from above in. Fig. 6, in perspective in Fig. 8. Whenthe filling tube is inserted in the valve sleeve it forces the end of thesleeve open as shown in perspective in Fig. 1, from below in Fig. 2, from above in Fig. 5, in section in Fig. 4 and end-on in Fig. 7.

When the top and the bottom of the valve sleeve are coextensive in length, that is, when they both end at the outer end of the reinforcing strip In, it is necessary for the. springs to fold two thicknesses of sleeve to close the valve. I have found that in this case the lower lip of the valve opening, which has no spring attached to it, tends to crease, which interferes with the folding of the end of the sleeve along the folding section. In some cases the sleeve end will fold somewhat less than and thus sealing of the valve opening may not be perfect. I have found that these difficulties can be obviated and better results secured when at least a section of the bottom of the sleeve is cut back to the folding line I2 to form in effect a receding lower lip [5, as shown best in Figs. 1, 2, 1 and 5. It is best to cut away a central section only of the lower lip, leaving triangular connecting web sections l6, as shown best in Figs. 1, 2, 4, 5 and 7. These web sections strengthen the upper lip which merely forms a fiap in this modification and also produce a better sealing at the sides ofthe clo-. sure.

While I have described what I consider to be the best embodiments of my valve bag closure, it is evident, of course, that various modifications can be made in the specific structures disclosed without departing from the purview of this invention. The leaf springs of my invention can be inserted in the top and bottom walls of my valve sleeve between laminations, for example," rather than with the use of reinforcing strips, or these springs can be sewed in position, if desired. The reinforcing strips can be passed entirelyaround the valve sleeve, if desired, rather than having their ends extend only partly around the valve sleeve to the side opposite the springs; as shown in'the drawing. My valve sleeve can" be inserted either in the top or in the bottom of a bag. It can be constructed of paper or fabric or partly of each. The leaf springs of my invention can be made of any suitable material, such as metal or plastic, provided that this material is sufiiciently strong and resilient. I usually employ spring steel or brass but a plastic, such as Celluloid, cellulose acetate or the like, is also suitable. Other modifications of my'invention which fall within the scope of the following claims will be immediately evident to those skilled in this art.

What I claim is:

1. An automatic closure for a valve-bag valve which is constructed with a sleeve flattened horizontally to form upper and lower walls, said sleeve passing between the flaps at the end of a bag and having a discharge end inside the bag, which comprises a pair of spaced-parallel arcuate leaf springs mounted transversely at the discharge end of the valve sleeve, one spring being mounted on the upper wall adjacent the discharge end of the sleeve while the second spring is mounted on the lower wall to the rear of the first and separated therefrom by a folding section of said sleeve, said springs being mounted on the sleeve in such manner that they are both convex towards the axis of the valve sleeve when open, whereby said springs tend automatically to spring into concentric position with the outer spring beneath the inner spring thereby automatically folding the discharge end of the top wall downwardly and inwardly over the bottom wall and closing the valve.

2. An automatic closure for a valve-bag valve which comprises a valve sleeve flattened horizontally to form an upper wall and a lower wall passing between and sealed to the flaps at the end of a bag, said sleeve having a valve mouth inside the bag, the lower wall being cut away at least partly at the valve mouth to leave a protruding upper lip and a receding lower lip, an arcuate leaf spring mounted on the upper lip and a second arcuate leaf spring mounted on the lower lip, said springs being spaced-parallel and separated by a folding portion of the sleeve and mounted in such fashion that they are both convex towards the axis of the sleeve when open, whereby said springs tend automatically to spring into concentric position with the outer spring beneath the inner spring thereby automatically folding the top lip downwardly and inwardly over the lower lip and closing the valve.

3. The valve closure of claim 2 wherein said lower wall is cut away at its center to said fold- 1,809,259

ing line, leaving strengthening webs on each end connecting the two lips.

4. The valve closure of claim 2 wherein said springs are mounted on the lips of the valve mouth by means of reinforcing strips which are sealed to said lips over said springs.

5. The valve closure of claim 2 wherein said springs are mounted on the lips of the valve mouth by means of reinforcing strips which are sealed to said lips over said springs in such position that the ends of the springs bear against the reinforcing strips.

6. The valve closure of claim 2 wherein the forward spring is mounted on top of the upper lip convex downwardly and the other spring is mounted on the bottom of the lower lip convex upwardly.

7. An automatic valve closure for a dispensing sleeve formed from a material of the nature of paper comprising a tubular sleeve flattened to form adjacent walls and having a valved dispensing mouth at one end, said closure comprising an arcuate leaf spring mounted transversely on one of the flattened walls of said sleeve adjacent its mouth, a second arcuate leaf spring mounted on the other wall of said sleeve spaced from but parallel to said first named spring, a folding line positioned between said springs, said springs extending substantially the full Width of said sleeve and having opposite curvatures when the sleeve is unfolded and tending to snap into concentric position whereby said valve mouth is normally held in closed position with the mouth end of the sleeve folded over at said folding line, said sleeve being adapted to unfold and to open during the dispensing operation.

8. The valve closure of claim '7 wherein both springs are mounted on the outside of the valve sleeve.

9. The valve closure of claim 7 wherein both springs are mounted on the inside of the valve sleeve.

10. The valve closure of claim 7 wherein one of said springs is mounted outside and the other inside the valve sleeve.

PER AUGUST STURE ANDRE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Williams June 9, 1931 Number

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