AN EXTRACTION ARM

Abstract

 An extraction arm, comprising a first tube (2) provided on top with connection means for connecting to a pneumatic vacuum source, a second tube (8) connected to a lower end (2b) of the first tube (2) by means of a first joint (9) configured at least to enable rotation of the second tube (8) relative to the first tube (2), a suction nozzle (10) disposed at a free end of said arm (1) and adjustment means (12) acting between the first and second tube (2, 8), wherein said adjustment means (12) comprises at least one gas spring (13) of the lockable type, operationally active between the first and second tube (2, 8), and a mechanism for locking and unlocking the gas spring (13), which mechanism is configured to adjust the locking position of the spring (13) in a continuous manner between a maximum stroke position and a minimum stroke position.

Description

[0001] The invention relates to a telescopic extraction arm which is particularly, (but not exclusively), destined for installation works in mechanical workshops, and predisposed for the extraction of fumes produced by motor vehicles' exhaust gases; the invention is also applicable to the field of welding fumes extraction and generally to the extraction of gaseous pollutants or harmful substances.

[0002] In detail, a commonly used exhaust gas extraction plant installed in a workshop, provides extraction arms extending from a same conduit - or duct - which duct runs along the workshop ceiling and is connected to a corresponding pneumatic vacuum source.

[0003] The arms of the known type exhibit a first tube extending downwards, which tube is carried by a carriage sliding along a rail formed on the duct, and a second tube coupled to the lower end of the first tube via a joint, so as to arrange a suction nozzle, (applied to a free end of the second tube), or other end element, in the desired extraction position.

[0004] The suction nozzle, or other end element, can be in turn movable relative to the second tube through a respective joint.

[0005] According to some embodiments, the arm may comprise a greater number of tubes, which are however connected one to another by means of respective swivel joints (elbows).

[0006] The suction nozzle, or other end element when in use, must remain stationary in a position opposite the gas source to be extracted, i.e. in front of the exhaust pipe of the car or relative to the welding equipment, and so on. So, tilting of the second arm (or of the arm sections located downstream of the first portion), should occur in an adjustable manner in order for it to remain in the desired position.

[0007] Currently, there are known arms whose joints, or "elbows", are adjustable according to a plurality of discrete angular positions by means of a mechanical lever which acts on an engagement coupling via a connection wire, which engagement coupling occurs between the two rotatable parts of the swivel joint by locking/unlocking rotation of the swivel joint. In greater detail, in this type of solutions, engagement generally occurs via toothed wheels.

[0008] Disadvantageously, the adjustment of the discrete type sets limits within the range of obtainable angular positions, wherein achievement of different configurations not provided by the kinematic coupling of the toothed wheels, is not possible.

[0009] Furtherly, due to the high pressure between the teeth of the toothed wheels, the weight of the arm causes the gear to become "jammed", thus, in order for the gear to be released, it is sometimes required an effort by the user besides the above mechanical lever having to be actuated. This type of coupling is also strongly subject to wear because of the high pressures involved.

[0010] There are further known extraction arms being provided with mechanical friction means relative to the swivel joints thereof, so that they can be tilted in an adjustable manner.

[0011] This solution of the known type exhibits the drawback that said mechanical friction means requires frequent maintenance and adjustment works by operators, which are necessary for compensating the consumption said means is subject to due to friction resulting in wear.

[0012] Therefore, a technical task of the present invention is to provide an extraction arm which is able to overcome the drawbacks of the prior art mentioned above.

[0013] In particular, it is an object of the present invention to provide an extraction arm exhibiting high flexibility in use, particularly as regards the range of reachable angular positions.

[0014] A further object of the invention, is to provide a extraction arm with excellent maneuverability and handling.

[0015] It is a further object of the invention to provide an extraction arm which is less susceptible to wear.

[0016] A further aim of the invention is to provide an extraction arm not requiring frequent adjustment and maintenance works.

[0017] The aim is fully attained by the inventive extraction arm, according to the contents of the claims described hereinafter.

[0018] The technical characteristics of the invention according to aforesaid aims, will better emerge from the content of the claims reported below and advantages thereof shall become more apparent from the following detailed description which is illustrated by way of non-limiting example in the appended drawings wherein:

• Figure 1 shows an extraction arm according to the invention;
• Figure 2 shows an enlargement of a part of the arm of Figure 1;
• Figure 3 illustrates a part of the arm of figure 1 in an alternative embodiment.

[0019] With reference to the appended figures, by 1 it is indicated an extraction arm according to the present invention.

[0020] The arm 1 comprises a first tube 2, a first (upper) end 2a of which is connected to movement means, particularly a carriage 3 which is slidable on preferably horizontal guide 4, which movement means enable a translational movement of the arm 1 along the guide 4. The guide 4 is formed externally, on an extraction duct 5, which extraction duct 5 is connected to a pneumatic vacuum source (not shown), which source may support a plurality of extraction arms of the type described herein, within an extraction plant. In mechanical workshops, the extraction duct 5 is for example fixed to the ceiling, wherein it takes on a stiff configuration.

[0021] Due to the connection to the extraction duct 5 via fluid communication, also the first tube 2 becomes a seat for pneumatic suction internally thereof.

[0022] In more detail, as visible in Figure 1, the first tube 2 exhibits a telescopic structure which is defined by an upper outer sleeve 6, and a lower inner sleeve 7, whose upper part is inserted inside the upper sleeve 6, thus protruding therefrom according to the configuration ("extension degree") assumed by the arm.

[0023] In alternative embodiments not illustrated but falling within the scope of the invention, the first tube may exhibit a non-telescopic structure as well as different configurations.

[0024] At the lower end of the first tube 2, a second tube 8 is rotatingly connected by means of a first joint 9, which is configured at least to allow rotation of the second tube 8 relative to the first tube 2 about an axis. In the illustrated embodiment, suitable for allowing use of the arm 1 as a fume extraction arm of vehicles exhaust gases, a suction nozzle 10 is applied to the end of the second tube 8 opposite the first tube 2, by means of a second joint 11, which second joint 11 is configured at least for allowing rotation about an axis of the suction nozzle 10 relative to the second tube 8.

[0025] In order for the joints to be better illustrated, in the appended figures there are not shown the tubular fittings defining continuity of the extraction arm 1.

[0026] However, it goes without saying that the arm 1 generally comprises suitable flexible tubular fittings (also of the known type), which are located relative to aforementioned joints.

[0027] In an alternative embodiment not illustrated, instead of the suction nozzle being applied to the second joint 11, there is provided a third tube applied thereto, which in turn supports the suction nozzle by means of a third joint. This solution assumes a two-joints or "elbows" arm configuration, (plus a third one for the suction nozzle), which arm is suitable for being used as a welding fumes extraction arm.

[0028] Adjustment means 12 are advantageously interposed between the first and second tube 2, 8. According to the inventive concept of the invention herein, said adjustment means 12 comprises at least one gas spring 13 of the lockable type which is intended to generate a thrust action onto the second tube 8, which thrust action occurs according to the lifting orientation of said second tube 8.

[0029] In a first embodiment (Figures 1 and 2), there are provided two gas springs 13 arranged laterally opposite one to another, outwardly of the encumbrance of the first joint 9.

[0030] Each spring 13 extends between a hinge 14 connected to the first joint, and an anchoring ring 15 which is fixed to the outer surface of the second tube 8. In the illustrated embodiment, the cylinder 13a of the spring 13 is connected to the joint 9, whereas the stem 13b is connected to the second tube 8, however, in different embodiments said assembly may be reversed.

[0031] In the embodiment of Figure 3, there is instead provided a single gas spring 13 positioned centrally in space (or angular sector), between the two tubes 2, 8 (in the upward direction of the second tube 8), i.e. in a position which is substantially so balanced as to not generate any torsional stresses within the first joint 9.

[0032] In detail, the springs 13 should be preferably mounted relative to the corresponding joint in such a way that, during actuation of the arm, they are able to balance the weight force acting on the suspended part of the arm 1 itself (i.e. downstream of the joint, relative to the gravity direction). Therefore, where there are used one or more thrust springs 13, the latter shall be mounted below the ideal axis of the joint, whereon they act (as shown in Figures 1 and 2).

[0033] In this case, the above mentioned hinge 14 connecting the springs 13, shall be in practice placed in the outer corner defined by the joint. Conversely, where there is provided a traction spring 13, the latter shall be arranged above the joint (i.e. above the axis thereof), as shown in Figure 3, and act relative to the inner angle formed therebetween.

[0034] According to the invention, the adjustment means 12 further comprises a locking and unlocking mechanism (not shown) of the gas spring 13, configured for adjusting the locking position of the spring 13 in a continuous manner, between a maximum stroke position and a minimum stroke position.

[0035] In one embodiment, the locking mechanism can be manually actuated through a respective lever via a wire connection, in order to activate locking and unlocking of the spring 13.

[0036] In an alternative embodiment, the locking mechanism includes a lock and unlock button of the spring 13.

[0037] In accordance with the embodiment providing three tubes (i.e. two-joints arm or "elbows", not shown), the arm 1 further comprises second adjustment means acting between the second and third tube. Said second adjustment means comprises at least one gas spring of the lockable type (for example, similar to those described above), which gas spring is operationally active between the second and third tube, thus generating a thrust action on the third tube occurring in the lifting direction of the latter. This locking and unlocking mechanism is further in turn configured for adjusting the locking position of the spring in a continuous manner, between a maximum stroke position and a minimum stroke position.

[0038] Also in this case, the locking mechanism may comprise a lock-unlock button of the respective spring, or a respective lever acting by means of a wire connection.

[0039] In one embodiment, such a condition may provide a single lever associated with both locking mechanisms and having a stroke, wherein a first portion thereof is concerned with the locking mechanism of the first adjustment means, while a second portion thereof, preferably adjacent to the first portion, is concerned with the locking mechanism of the second adjustment means.

[0040] It should be appreciated that the gas spring, active between the second and the third tube, can be arranged at the second joint according to same arrangements as described above in relation to the spring 13, which spring 13 is active relative to said first joint, i.e. between the first and second tube 2, 8.

[0041] The present invention attains the set aims, thus overcoming the drawbacks of the prior art.

[0042] Use of a lockable gas spring, connected to the movable extraction arm, allows to obtain a continuous adjustment of the arm positioning, wherein any type of final configuration thereof may be obtained.

[0043] Adjustment of the arm positioning is further facilitated owing to the recall/ thrust action exerted by the spring, with considerable benefits in terms of maneuverability of the arm.

[0044] In addition, the gas springs do not require any particular maintenance, nor do they need any end adjustment (unlike the friction means of the prior art), thus resulting to be extremely practical as well as cost-effective.

Claims

1. An extraction arm, comprising:

- a first tube (2) provided on top with connection means for connecting to a pneumatic vacuum source;

- a second tube (8) connected to a lower end (2b) of the first tube (2) by means of a first joint (9) configured at least to enable a rotation of the second tube (8) relative to the first tube (2);

- a suction nozzle (10) disposed at a free end of said arm (1);

- adjustment means (12) acting between the first and second tube (2, 8);
characterized in that said adjustment means (12) comprises at least one gas spring (13) of the lockable type, operationally active between the first and second tube (2, 8), and a mechanism for locking and unlocking the gas spring (13), configured to adjust the locking position of the spring (13) in a continuous manner between a maximum stroke position and a minimum stroke position.

2. The arm according to claim 1, wherein said adjustment means comprises, between said first and second tubes (2, 8), a gas spring (13) disposed in a substantially central position on said joint (9).

3. The arm according to claim 1, wherein said adjustment means comprises, between said first and second tubes (2, 8), at least one gas spring (13) disposed laterally relative to said first joint (9), preferably a pair of gas springs (13) disposed symmetrically on opposite sides of said first joint (9).

4. The arm according to any one of the preceding claims, wherein said at least one gas spring (13) is an extension spring.

5. The arm according to any one of the preceding claims, wherein said at least one gas spring (13) is a compression spring.

6. The arm according to any one of the preceding claims, wherein said arm (1) further has a third tube connected to one end of the second tube (8) opposite the first tube by means of second joint configured at least to enable a rotation of the third tube relative to the second tube (8), and wherein said arm (1) further comprises second adjustment means acting between the second (8) and the third tube, said second adjustment means comprising at least one gas spring of the lockable type, operationally active between the second and the third tube, and a mechanism for locking and unlocking the gas spring, configured to adjust the locking position of the spring in a continuous manner between a maximum stroke position and a minimum stroke position.

7. The arm according to the preceding claim, wherein the two locking mechanisms of the two adjustment means are connected to a same actuating lever, said actuating lever having a stroke, wherein a first portion thereof is concerned with the locking mechanism of the first adjustment means, while a second portion thereof, preferably adjacent to the first portion, is concerned with the locking mechanism of the second adjustment means.

8. The arm according to claim 6 or claim 7, wherein aforesaid gas spring is disposed between said second and third tubes in a substantially central position on said joint.

9. The arm according to at least one of claims 6 - 8, wherein a gas spring is disposed between said second and third tubes in a lateral position relative to said second joint, preferably a pair of gas springs disposed on opposite sides of said second joint.

Drawing