TECHNICAL FIELD

The invention pertains to the technical field of airless spray equipment, for example airless spray guns or high pressure hand-held spray guns. In particular, the invention relates to safety mechanisms for such airless spray equipment.

BACKGROUND

Airless spray equipment, such as an airless paint sprayer, is customarily employed in many painting applications. For instance, it is used by contract painters to paint heavy duty industrial, chemical and marine coatings and linings. Advantages include (1) speed, since airless spraying is at least 4 times faster than brush applications and at least 2 times faster than roller applications; (2) quality, since airless sprayers produce an even coat of paint on all types of surfaces, leaving a high quality finish; and (3) versatility, since airless sprayers can be used for a wide range of coating materials. According to conventional airless spraying techniques, the paint or other fluid is maintained in the airless spray equipment under very high hydraulic pressure. On actuation, this equipment typically produces a spray from about one to 500 bar (7200 PSI). The high pressures atomize the paint (or coating), using different diffuser (or tip) sizes to achieve desired atomization and spray pattern size. Airless spray equipment, particularly manually operated equipment such as airless spray guns, is thus inherently hazardous, as the paint spray in close proximity to the skin of the operator or a bystander may cause injury to the skin and further. The highly pressurized spray is capable of penetrating exposed portions of the body, thereby injecting paint into the body. This may initially look like a cut, but it is a serious injury that can result in amputation. Fluids splashed in the eyes can also cause serious injury.

Due to the high pressure at which the fluid is emitted, a strong recoil action may also occur when these types of gun are triggered. If unprepared, the operator's hand could be forced back towards his body or if he is not standing securely, he could lose his balance and fall, resulting in serious injury. To prevent accidental or unintentional activation of tools such as a spray gun, but also of e.g. a drill or electric screwdriver, a trigger lock mechanism should be provided. Document US4105164 discloses a trigger lock mechanism for hand held spray guns, with an arm normally positioned to block operation of a trigger of the gun, but movable by an operator to release the trigger for operation. This trigger lock is deemed particularly useful with airless paint spray guns, and the arm is generally U- shaped and secured at its free ends to opposite sides of the trigger. The closed end of the arm extends around the rear of the gun whereat a housing normally blocks rearward movement thereof, and therethrough the trigger, when the trigger is in its unoperated position. By deliberate action an operator may move the closed end of the arm out of blocking engagement with the housing to release the trigger for movement to its operated position. Then, with return of the trigger to its unoperated position, the arm automatically returns to its position blocking operation of the trigger.

However, as described, the operator (or user) must manually position the trigger lock mechanism back to its unoperated position in order to be able to use the trigger. This leads to a slight delay in time before the gun can be activated and can be cumbersome in some practical work situations.

Document US2007228190 discloses a hand-held trigger operated spray gun for dispersing high pressure liquids. The spray gun also has trigger lock features, comprising an elongated trigger lock member supported on the trigger for pivotable movement between an inactive position adjacent the trigger and an active position in outwardly pivoted relation to the trigger. The spray gun's body is formed with a recess for receiving a free end of the trigger lock member when the trigger is in the deactuating position and the trigger lock member is in an active position. The trigger lock member is formed with a locating nib engageable with the trigger for positioning the trigger lock member in predetermined relation to the trigger lock member receiving recess when the trigger is in the deactuated position. Furthermore, the trigger is pivotably mounted in depending relation to the handle portion, and the trigger lock member is pivotably mounted adjacent a lower end of the trigger. This type of trigger lock is for instance not spring-biased, and the document further mentions that the trigger lock can be moved to and retained in an inactive position during usage of the spray gun and can also be located in position with the assistance of the locating nib for locking the trigger during periods of non-use, for preventing accidental dangerous high pressure discharge from the spray gun. However, there remains a need in the art for an automatic trigger lock safety mechanism that does not require the explicit attention of the operator, and locks the spray gun immediately upon fully releasing the trigger. Document US4225087 discloses an automatic safety mechanism for airless spray equipment such as airless spray guns of the type having a trigger mechanism for actuating a gun spraying mechanism by pivotal movement of the trigger means toward the hand-grip means. It includes a rigid locking member spring-biased and disposed for automatic operative interposition between said hand-grip and trigger means upon full release of said trigger means.

However, in one embodiment the locking means is connected to the spray gun via two hinges, making it less easy to disassemble if so desired, e.g. for cleaning or servicing purposes. Furthermore, the type of spray gun is of a wholly different type than the one envisioned in the present invention. In an alternate embodiment, a lever is provided near the top of both the trigger and the handle, which does not appear comfortable to manipulate with one hand.

The present invention aims to resolve at least some of the problems mentioned above.

The invention thereto aims to provide an automatic trigger lock safety mechanism and a locking method for airless spray equipment which substantially minimizes the hazards associated with the use of such equipment.

It is another object of this invention to provide a safety mechanism and a locking method for manually-operated airless spray equipment, such as airless spray guns, which is automatically activated on full release of the spray equipment actuating mechanism.

It is an additional object of this invention to provide a safety mechanism and a locking method for airless spray equipment, such as airless spray guns, which automatically functions to prevent accidental operation of the spray equipment actuating mechanism, but which can be readily counteracted by the equipment operator.

SUMMARY OF THE INVENTION

The present invention provides an automatic trigger-lock safety mechanism, comprising : - a handle;

a trigger generally parallel to the handle for rotating between depressed and released positions;

pivoting means coupled to said trigger, comprising a rod-like locking member which is in a resting situation positioned generally transverse to said trigger, whereby said locking member extends through an opening in said trigger.

In a second aspect, the present invention provides a device comprising an automatic trigger-lock safety mechanism according to an embodiment of the invention, such as an airless spray gun or a high pressure spray gun.

In a third aspect, the present invention provides a method for automatically locking a device, said device comprising a handle and a trigger, whereby said trigger is locked in an inoperable state when inactive via said pivoting means coupled to said trigger, and whereby said locked status is removed by applying a force to said trigger, thereby displacing the pivoting means towards a position which is substantially parallel to said trigger and handle.

As the principal advantage, the operator of such a device is protected from inadvertent actuation of said device, since after the trigger has been fully released, the trigger-lock safety mechanism must be intentionally disengaged to permit actuating movement of the trigger. This substantially minimizes hazards associated with the use of such a device, such as injection hazards and unexpected recoil, which can both result in serious bodily injuries.

FIGURES

Figure 1 depicts a device according to an embodiment of the invention, in particular an airless spray gun with an automatic trigger lock safety mechanism and a typical handle.

Figure 2 depicts a device according to an embodiment of the invention, in particular an airless spray gun with an automatic trigger lock safety mechanism and a handle provided with a central recess. Figure 3 depicts a sequence of steps in an embodiment of a method for unlocking an automatically locked airless spray gun as described in Figure 1. DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns an automatic trigger-lock safety mechanism, a device comprising an automatic trigger-lock safety mechanism, and a method for automatically locking a device.

Unless otherwise defined, all terms used in disclosing the invention, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

As used herein, the following terms have the following meanings:

The term "automatic" as used herein refers to having the capability of moving independently of an operator's actions, e.g. automatically locking a device to an inactive condition.

The term "wetted parts" as used herein refers to materials that come in direct contact with the sprayed medium (gas, liquid or coating).

The term "proximal" as used herein refers to being closer to the body, e.g. the hand of a person who uses a device, such as a spray gun.

In a first aspect, the invention provides an automatic trigger-lock safety mechanism, comprising :

- a handle;

a trigger generally parallel to the handle for rotating between depressed and released positions;

pivoting means coupled to said trigger, comprising a rod-like locking member which is in a resting situation positioned generally transverse to said trigger, whereby said locking member fully extends through an opening in said trigger.

By providing said opening in said trigger, said locking member can advantageously become comprised within said trigger, e.g. by collapsing into a recess which is provided at the back of a typical trigger. The opening is designed as such, so that said trigger can completely receive said locking member. This facilitates the use of said trigger-lock safety mechanism, as said trigger can be squeezed adequately and easily. Said locking member of said pivoting means, extending through a hole in said trigger and positioned generally transverse to said trigger, comprises a trigger-connection means to connect said locking member to said trigger. In a preferred embodiment, said trigger-connection means of said locking member comprises at least one spring. In an alternate embodiment, said trigger-connection means of said locking member comprises at least one magnet. In yet another embodiment, said trigger-connection means of said locking member comprises at least one weighted element, thereby making said locking member susceptible to a weight transfer. Said locking member may also be connected to said trigger through combinations of trigger-connection means, i.e. at least one spring, at least one magnet and/or at least one weighted element.

As an effect, said pivoting means, in combination with said locking member extending through said trigger, ensures an automatic locking of said trigger, so that an operator does not need to manipulate e.g. a lever when he wishes to inactivate said trigger. When said trigger is released suddenly, either by coincidence or on purpose, the pivoting means will automatically return to its original position and lock said trigger, so no pressurized material can leave the spray gun.

The compact design of said pivoting means coupled to said trigger also allows for easy assembly onto a device such as an airless spray gun, even onto an existing device after minimal modifications. It equally allows for easy disassembly, e.g. for cleaning or servicing purposes.

In a preferred embodiment of the invention, said pivoting means further comprises at least one guiding element for engaging or disengaging said trigger-lock safety mechanism.

Said guiding element may further comprises at least one sliding or rolling element, preferably a wheel, at the proximal end of said locking member, to enable said guiding element to run up or down said handle.

In another preferred embodiment of the invention, said guiding element comprises a central recess provided in said handle, defining a central plane, and said recess being able to receive the proximal end of said locking member. Said guiding element may further comprise at least one sliding or rolling element, preferably a wheel, at the proximal end of said locking member to enable said guiding element to run up or down said recess provided in said handle. Said guiding element advantageously ensures that said pivoting means can be efficiently displaced, such that said trigger is locked in an inoperable state when inactive, and whereby the locked status is removed by applying a force to said trigger, thereby displacing the pivoting means towards a position which is substantially parallel to said trigger and handle.

Said automatic trigger-lock safety mechanism can be manually disengaged by a user, permitting an actuating movement of said safety mechanism.

In a second aspect, the invention provides a device comprising an automatic trigger- lock safety mechanism as described above. As an advantage, the operator of such a device is protected from inadvertent actuation of said device, since after said trigger has been fully released, said trigger-lock safety mechanism must be intentionally disengaged to permit actuating movement of said trigger. This substantially minimizes hazards associated with the use of such a device, such as injection hazards and unexpected recoil, which can both result in serious bodily injuries.

Preferably, said handle can be removed from said device for cleaning or servicing purposes, e.g. by unscrewing or by removing from a snapping means. Said handle may further comprise a positioning means for positioning said recess towards said trigger. Preferably, said positioning means comprises a screw thread, a snapping means or a guiding mark. This advantageously ensures that the handle is correctly assembled before its first use, or correctly repositioned after cleaning or servicing interventions. In a preferred embodiment of the invention, said device is connectable to a source of fluid or gas. Said device may further comprise a hand-held spray gun, such as an airless spray gun or a high pressure spray gun, a fuel gun, an electric screwdriver, or an electric drill. Said automatic trigger lock safety mechanism can indeed also be beneficial in other types of equipment whereby an operator may be at risk when said device accidentally remains actuated. In the case of airless spray guns, a high fluid pressure is used to atomize e.g. paint. Said fluid is thus forced through a diffuser with e.g. an elliptical shaped orifice, whereby said orifice shape and size help determine the spray pattern size, shape and material flow rate. Such high pressures are known to cause increased material bounce-back and increased diffuser wear. In a preferred embodiment of the invention, the material of said device comprises steel, stainless steel, aluminum, rubber, silicone and/or plastic. The material of the wetted parts of said device may comprise steel, stainless steel, aluminum, acetal, polyethylene, nylon, polypropylene, carbide, tungsten carbide, polyurethane and/or solvent-resistant o-rings. Such pressure-resistant materials are standard in airless spray guns. This list is not exhaustive, as other materials that can withstand high pressures may also be used. Furthermore, this list does not limit the materials for connected equipment such a hose, a liquid container, etc.

In a third aspect, the invention provides a method for automatically locking a device as described above, said device comprising a handle and a trigger, whereby said trigger is locked in an inoperable state when inactive via pivoting means coupled to said trigger.

Such a device, comprising a handle and a trigger, is unlocked by applying a force to said trigger, such that pivoting means are displaced by the following simultaneous actions:

a) rotating a rod-like member of said pivoting means along a pivot provided in said handle;

b) displacing the proximal end of said rod-like member of said pivoting means along the generally vertical axis of said handle, by means of a guiding element comprising at least one sliding or rolling element at the proximal end of said locking member and/or a central recess provided in said handle; and

c) displacing the rod-like locking member of said pivoting means towards a position which is substantially parallel to said trigger and handle, thereby collapsing into said trigger and rotating said trigger to a depressed position whereat said device is in an active condition.

Said device may further be automatically locked to an inactive condition by removing said force from said trigger, thereby exerting a reaction force on said pivoting means such that said trigger is prevented from rotating to the depressed position thereof.

Advantageously, the operator is enabled to fully operate the spraying mechanism with one hand and shut off the flow of e.g. paint without engagement of the safety mechanism.

Also, if said trigger is released suddenly, either by coincidence or on purpose, the pivoting means will automatically return to its original position and lock said trigger. In the case of a pressurized spray gun, where said trigger becomes locked, the stem is closed automatically and no material can leave the spray gun, even when the spray gun is under a 500 bar (7200 PSI) pressure.

Likewise, if said spray gun accidentally falls to the floor, or any obstacle collides with said spray gun, the automatic trigger lock safety mechanism system will lock the trigger, so no pressurized material can leave the spray gun. It is supposed that the present invention is not restricted to any form of realization described previously and that some modifications can be added to the presented example of fabrication without reappraisal of the appended claims. The invention is further described by the following non-limiting drawings which further illustrate the invention, and are not intended to, nor should they be interpreted to, limit the scope of the invention.

Figure 1 shows a device according to a possible embodiment of the invention, in particular an airless spray gun with an automatic trigger lock safety mechanism. The spray gun features a body (1) defining an interior. Within this interior, a flow path for a fluid such as paint or coating is present. The body further comprises an inlet in communication with a fluid source, such as a paint container, and an outlet. The body's outlet is a valve having a valve member in the flow path, which is movable between a closed position and an open position in which fluid travels from the inlet to the outlet. A diffuser (2) is connected to the outlet, to diffuse the atomized fluid. Additionally, a guard (3) is connected to the diffuser (2) at the front of the spray gun, to protect the operator from coming into contact with the diffuser (2) when spraying and to hold the diffuser (2) in place. At the bottom of the body (1), a handle (4) is attached to allow an operator to hold the spray gun. At the bottom and generally parallel to the handle (4), a trigger (5) is attached to the body ( 1). The trigger (5) can be rotated between depressed and released positions, which results in actuation and deactuation of the spray gun, respectively. A trigger guard (6) is connected to the bottom of the handle (4) and to the bottom of the body (1), to protect the trigger (5) from being depressed, e.g. should the spray gun accidentally fall. A fluid source can be connected through the hose connector (7) at the bottom of the handle (4). The automatic trigger lock safety mechanism of this embodiment comprises a pivoting means (8) coupled to the trigger, thereby locking the trigger in an inoperable state when inactive. The pivoting means (8) further comprises a locking member (9) which is positioned generally transverse to the trigger (5) in a resting situation, and extends through an opening in the trigger (5), thereby being connected to the trigger (5) via a pivot (10). The locking member (9) is connected to the trigger via a trigger- connection means, which is in this embodiment a spring (11) that is connected to the trigger (5). The locking member (9) is engageable by an operator to move from a locked position to an unlocked position whereat the spray gun is in an active condition, by applying a force to the trigger (5), thereby displacing the pivoting means towards a position which is substantially parallel to the trigger (5) and handle (4). To facilitate the pivoting motion of the locking member (9) during actuating of the trigger (5), the locking member (9) in this embodiment further comprises two wheels (12) at the rear (i.e., towards the handle), to run up or down the handle (4) along a path that extends from approximately the middle of the handle to the top of the handle. When the locking member (9) thus becomes collapsed between the handle (4) and the trigger (5), the trigger (5) becomes activated and the spray gun can diffuse its liquid. Upon release of the trigger (5), the spring-biased pivoting means (8) automatically returns to its locked position whereat the spray gun is again deactivated.

Figure 2 shows an alternate embodiment of the automatic trigger lock safety mechanism in a spray gun according to the present invention. Here, the handle (4) comprises a central recess (13) to receive the wheels (12) at the rear of the locking member (9). In addition to the mechanism described in Figure 1, this recess (13) can further facilitate the pivoting motion of the locking member (9) during actuating of the trigger (5), and thus actuation of the spray gun. The recess (13) can be of any size and shape that fits within the handle (4). For instance, a longer and deeper recess could allow a more compact pivoting means (8) as a whole. A simpler locking member (9) without wheels may also be received by the recess (13) as pictured in this embodiment. This would further minimize the complexity of the pivoting means (8). To ensure that the handle (4) is correctly assembled before its first use, or correctly repositioned after cleaning or servicing interventions, a positioning means for positioning the recess towards the trigger is provided. For instance, the bottom of the body (1) where it connects with the handle (4) and the top of the handle (4) itself, are here both provided with guiding marks (14), which should be properly aligned. Alternatively, the internal screw thread which connects the handle (4) with the body (1) may be precisely designed as to analogously align the recess (13) with the trigger (5).

Figures 3a-d show a sequence of steps in a method for unlocking an automatically locked airless spray gun, using the embodiment as illustrated in Figure 1. Figure 3a assumes an operator is already holding the inactive spray gun in his hand, while the arrow depicts the resulting motion of the operator pushing down the rod-like locking member (9) of a spring-biased (10) pivoting means (8) as he starts to squeeze the trigger (5). Figure 3b consequently shows the motion whereby locking member (9) of the pivoting means (8) is being pushed further down by the operator, while the two wheels (12) at the rear of the locking member (9) move upward along the handle (4). By continuing the squeezing motion executed by the operator, Figure 3c shows the trigger (5) being rotated further to a fully depressed position and the locking member (9) of the pivoting means (8) being fully collapsed and aligned with both the handle (4) and the trigger (5), thereby effectively activating the spray gun. In contrast, Figure 3d shows the result of the operator having removed force from the trigger (5), whereby a reaction force is exerted on the spring-biased (11) pivoting means (8), such that the trigger (5) is prevented from rotating to the depressed position again, thereby automatically locking the spray gun back in its inactive condition.

Other, intermediary positions of the pivoting means (8) in the present automatic trigger lock safety mechanism can be considered as occurring sequentially in- between the positions that are already depicted in Figures 3a-d.