Ball valve basket with idiot proof safety.

The invention relates to an improvement for a hand-held foam applicator or "dispensing gun" for delivering a fluent material for example a foam producing material , more particularly one component polyurethane foam.

Such applicator comprises typically a handgrip, a body, a steel barrel with a nozzle tip, an adaptor or fitting for attaching a can - also called a "basket" , and a needle assembly comprising a pressure spring with one end obturating the nozzle tip and being drawn back via a trigger arrangement for delivery of the foam from the can through the barrel and the nozzle.

Between the can and the gun, there is usually a valve assuring the connection. This allows the easy and neat change from one can to another.

Nowadays for this purpose a non-return ball valve with spring is used in polyurethane guns. But this system has a few disadvantages:

-When foam remains in the basket after cleaning, these remains will cure out and form a barrier. This barrier makes good closing impossible. So, after removing the can, foam will come out of the gun when filled with foam under pressure.

-When the gun is cleaned for example with acetone, a mix of foam and acetone sticks on the basket. This causes an adhesion between the basket and the non-return ball. To

remove this sticking, users usually take a thin, sharp object to push on the Teflon ball.

This causes damage of the line closing system between the ball, for example a Teflon ball, and the basket. -The non return ball needs a minimum pressure to open which is to be substracted from the pressure of the delivered foam in the gun. This leads to less output and more foam remains in the can with a residual pressure therein.

For these reasons, another type of adaptor has been developed and proposed on the market (for example the adaptor NBS- F) . This "F-adapter" is a standard basket, but without non return ball. The opening-closing of this system is regulated by a well-known ball valve. This system of the prior art is called the Ball Valve Basket

According to one aspect of the invention, it has now been found that the distance between the ball valve and the opening of the can in such adapters as the "F-adapter" is very important because foam can cure out therebetween. For measuring this distance the opening is preferably taken at the lowest level of the lowest cone which is located on the same height than the end of the can valve stem. The system is surprisingly far more efficient and reliable when the distance is as small as possible. This means that the outer end of the stem of the can valve should almost "touch" the ball valve. The distance should be less than the prior art distance of 30 mm or more. Preferably the distance should be less than 15 mm, still preferably less than 7 mm.

However, this improved system has still some disadvantages.

When the gun is filled with foam under pressure and a user turns the ball valve open once the can has been removed, he could get foam splashing in his eyes or on his face.

According to the present invention, there is therefore provided a further possible improvement in the construction of a foam applicator.

One object of the invention is indeed to provide a new closing system for the basket in a dispensing gun to prevent such accident. The arrangement allows the user to turn on the ball valve only when there is a can attached to the gun. This can may be filled for example with PU-foam or PU-cleaner.

The invention is directed to an adapter or "basket" for assembling a pressurized can to a gun comprising a ball valve and a safety member wherein the safety member is a movable member which will physically prevent, in normal operation, the handle of the ball valve of being in an open position in the absence of a can adapted on said basket.

The safety feature may consist of a member slidable under the basket, such as a drawer movable along guiding means integral to the basket, with a means which will force, in normal operation, the handle of the ball valve of being in a closed position in the absence of a can adapted on said basket .

More particularly, the invention provides an improved dispensing gun for fluent products such as foamable material wherein the gun comprises in combination a product inlet passage and an outlet passage, the inlet passage comprising a basket for adapting a pressurized can and a

ball valve with an axle and a handle. There is provided a safety arrangement consisting in a movable member, pivotable or slidable, biased by a spring associated to the basket, which in the absence of a can or associated adaptor ring will mechanically prevent the handle of the ball valve of being in an open position. According to the invention the handle actuates the axle of the opening/closing means of the ball valve, said handle being at least partly of non circular cross section.

The axle will be locked relative to the basket and the associated gun, in a closed position of the ball valve, by the fact that at least one transversal section thereof is not circular and cannot rotate due to the blocking action of the movable member. The movable member may be a drawer with a lateral slot or oblong opening traversed by said axle or may be a part of a pivotable arm with a portion thereof having a cam profile cooperating with the outer surface of the non circular section of the axle.

A further object of the invention is to provide an automatic system closing a ball valve when no can is affixed to the gun.

The invention will be better understood with reference to the following detailed description of the attached drawings provided in an exemplative way only. It will be understood that the basket may be embodied in a number of different forms and certain of the parts may be constructed and arranged in a different manner. In the drawings corresponding reference characters refer to same or like members throughout the following figures.

Fig. 1 is a view of a ball valve basket to be adapted on a gun, according to the prior art

Fig. 2 is a sectional rear view of the ball valve of fig. 1

Fig. 3a is a perspective sectional view of a ball valve in the open position

Fig. 3b is the corresponding partly sectional view of a ball valve in a closed position

Fig. 4 illustrates the basket coupled with the can

Fig. 5 is a general view of a gun with an adapter and a safety arrangement according to the invention

Fig. 6 and 7 are detailed views of an embodiment of the invention wherein the handle of a ball valve is in open and closed position

Fig. 8 is a more general view of the safety member arrangement

Fig. 9 represents the gun with the can affixed on the adapter

Fig. 10 is a partial perspective view from the bottom

Fig. 11 shows the adapter when no can is affixed Fig. 12 illustrates another embodiment of the invention

Figs. 13a, b, c are schematic side views illustrating various positions of the axle (cross-sectioned) in the slot provided in the safety member according to one embodiment of the invention. Figs. 14 and 15 illustrate another embodiment of the invention wherein the safety arrangement associated to the basket is made of a pivotable arm.

Figs. 16 and 17 show a slightly amended embodiment of the one shown in Figs. 14 and 15.

As shown in Figs. 1 and 2, prior art provides a ball valve basket 1 with a handle 2 to turn an axle 11 and an associated upper adapter 3 for receiving a can or more frequently a coupling ring adapted to a can. The ball valve

20 regulates the opening-closing to the passageway 41 to the gun. The assembly "can-ring" may be screwed to the gun via a lower threaded section 4.

The distance A (figs. 2-4) should however be designed as short as possible as shown in fig.3a and 3b (sectional view, open and closed valve) and 4 (sectional view, open valve) in order to prevent accumulation of a product able to cure between the valve and the can. This means that the outer top of the stem of the can valve should almost "touch" the ball valve.

In Fig. 4 the can valve is illustrated in a downright position with the outer end of can valve stem 22 of the can valve 21 just above the ball valve 20 of the basket 1. The metallic cup 23 of the can (not shown) , a rubber grommet 21 and the sealing members (ring 26, seat 25) of the ball valve are also indicated.

Fig. 5 shows a complete assembly according to the invention. There is a can 5 with a coupling ring 6 to be screwed or, in another embodiment, clamped in a basket 3. The gun has a trigger 7 for moving a needle (not shown) inside the barrel 14 and closing/opening the nozzle 8. There is illustrated a safety arrangement 9 in the form of a drawer 13 that can be pushed or slided under the basket on one side, (here away from the barrel 14 side, the front side) against a compression spring (16, fig. 10) . When released, due to the biasing action of the spring, the member 13 will come back at its initial position generally achieved in the absence of a can.

There is provided laterally on the safety arrangement in the form of a drawer 13, a longitudinal slot 10 allowing

the drawer 9 to freely slide transversely to the axle of the ball valve handle.

If a can has been affixed the vertically extending end portion 15, integral to the drawer, will contact in abutment or engage the can wall or ring-can assembly 5, 6 in a blocking or locking arrangement. The safety member 13 is immobilized in a particular position and biased by the spring 16. For this particular position the handle's axle of the ball valve traversing the safety drawer through a longitudinal slot 10 will be positioned along the slot 10 at a specifically enlarged portion 12 provided laterally on this member 9, and will be able to rotate by 90° and therefore to open the inlet passage. In all other longitudinal positions of the drawer 9 the handle cannot rotate because the highest dimension of the cross-section of its axle 11 does not permit rotation in a non-enlarged part of the slot 10.

FIG. 6 is an enlarged portion of Fig. 5 showing the enlarged section 12 of the slot 10 and the axle 11 in the open position. The largest cross-sectional dimension of the axle is then vertical.

In this position of the axle 11 along the slot 10 the user can indeed activate the ball valve 20. The user can freely open or close it because in this position there is a can on the gun. The ball valve handle is in the vertical position, this means that the ball valve is opened. In this position, the user is not able to push on the "PUSH" button 13 because the safety system cannot slide on the basket. As mentioned, the "half round" axle prevents the basket from sliding out of this position.

In FIG. 7 the handle has been turned by 90°, so the ball valve is closed. In this position it is possible to slide the safety member 9.

In FIG. 8 it is shown in a more general view that the safety member 9 can slide under the basket 3 when the Push button 13 is actuated, the handle remaining fixed relative to the basket 1 with upper adapter 3 and the body of the gun. It is to be noted that the member 15 extending upwardly from the end of the safety drawer 9 may comprise a portion 18 extending back inwardly. This feature will render impossible the upward removal of the can in the "open" position of the safety member (9) .

In FIG. 9 the safety arrangement is fully pushed against the basket 1, now the can and ring assembly (6,10) may be engaged or disengaged and can be turned in/out from the basket 3. The vertically extending locking portion 15 of the safety member 13 is no longer obstructing the ring. It should be noted that according to the invention this is only possible when the ball valve is closed.

FIG. 10 is a part view from bottom illustrating the spring attached to the basket 1 and biasing the safety drawer 9 so that at rest the latter is in a closing configuration.

As shown in FIG. 11 once the can is removed, the safety system 9 springs back towards the front of the gun. This is caused by the metal spring 16 on the bottom of the system. In this position it is impossible to open the ball valve because the safety member or drawer is not in the right position.

Only when the user 1) pushes on the button, 2) screws on the can and release the button shall the slot of the safety member be in a position permitting the ball valve to be activated.

In FIG. 12 the only difference relative to the first embodiment is the presence of a can handle in the form of a plate 30 replacing the push button. In this variant the handle 30 operates to cause the sliding of the safety member 9. When the user wants to put a can on the gun, he has still to slide the safety member with the associated slot. However in this embodiment, this is achieved not by using a push button 13 (by hand) as in the previous design, but preferably by pushing, then releasing, the can 10 against the can handle 30 during the process of attaching the can-ring assembly to the gun, for example by screwing.

FIG. 13 shows schematically the axle traversing the slot in 3 different positions. Position A is the resting position without can affixed to the basket (not shown) . In position B the spring is compressed permitting the positioning of a can (not shown) on the basket. In position C the drawer is released and its portion 15 is in contact at 17 with the can wall or coupling ring to afford the rotation of the axle 11 positioned at the enlargement 12 of the slot 10.

FIGS. 14 and 15 illustrate another embodiment of the invention wherein the safety arrangement associated to the basket 3 is made of an interconnected double arm 60 pivotable at one end about an axle 61 associated to the body of the basket 1. The axle has a truncated circular transversal section. The base 63 of the arm has a profile acting as a cam and cooperating with the outer surface of at least part the ball valve axle 62.

In Fig. 14 there is no can and a torsional spring (not illustrated) maintains and presses the arm in an upward position because it is not impeded by the presence of a can. It is stopped only by the body of the basket. In this case, the shape of the lower pivoting part of the arm is such that this part blocks the handle axle in its closed position, pressing on the axle's outer planar portion 67, corresponding to the closed position so that the axle cannot be turned to the open position.

FIG. 16 is a sectional view in perspective where the arm of Fig. 15 is illustrated in the presence of a can 6 and its fitting ring 64 with thread 65, and is therefore rotated downwardly. In this position, the profile 63 permits the rotation of the axle 62 by 90° with its larger sectional dimension vertical permitting consequently the opening of the ball valve.

In FIGS. 16 and 17 there is shown a side view of slightly different embodiment where the profile comprises a recess enabling the rotation of the axle only at a position of the upper part of the arm contacting a can positioned in said basket. A torsional spring 69 is illustrated.

As shown in Fig. 17, the presence of an affixed can will make the arm pivoted to a certain degree, displacing the base of the arm so that the rotation of the axle is free and the handle (not illustrated) may be actuated to open the ball valve.

Although only presently preferred embodiments of the invention have been specifically illustrated and described herein, it is to be understood that various variations may

be made in the basket without departing from the scope of the invention as defined in the claims.