Pneumatic sanding machine with automatic dust extraction system

Abstract

The invention relates to a pneumatic sander comprising a pneumatic dust extraction device for sanding and a connection module (1) for connecting the sander and the extraction device to a compressed air source, said connection module (1) comprising: - an internal conduit (16) having an air inlet (13) connected to a compressed air source, - a first air outlet (14) supplying air to the sander and disposed in communication with the air inlet (14) by a first air passage (A, A'), - a second air outlet (15) supplying air to the dust extraction device for sanding and disposed in communication with the air inlet (13) by a second air passage (B), - a movable shutter (10) mounted in the internal conduit (16), said movable shutter (10) being in the rest position when said sander is stopped,and forced by a spring element (17) to at least partially close the first air passage (A) and the second air passage (B), said connecting module (1) being configured so that: - when the sander is switched on, said compressed air source delivers a flow of compressed air into said first air passage (A, A') to force said movable shutter (10) against said spring element (17) so as to open the first air passage (A, A') and allow the air flow to pass from the air inlet (13) to the first air outlet (14) and then to said sander, and at the same time to open the second air passage (B) to allow the air flow to pass to said motor of said suction device, causing said suction device to suck up the dust from said sander; - when said sander is switched off, said spring element (17) forces said movable shutter (10) to its rest position. Fig. 4,

Description

Title of the invention: Pneumatic sanding machine with automatic start-up of a dust extractor. Field of the invention

[0001] The field of the invention is that of pneumatic suction devices, and in particular of suction or extraction of dust.

[0002] Such suction devices can be implemented to vacuum up dust created by the operation of a tool, such as a pneumatic sander for example, for the repair of car bodies. Previous art

[0003] In the field of automotive body repair, the sanding operation is combined with the use of a dust extraction device to collect sanding particles, particularly aluminum particles, hereinafter also referred to as dust. By being extracted, the particles do not pollute the ambient air of the garage and do not harm the health of the bodywork technician.

[0004] For occasional use or for hard-to-reach areas, complete mobile units consisting of a central vacuum unit (a vacuum device on wheels, for example) and an electric sander are known.

[0005] In order to comply with the ATEX standard, the electrical components of electric sanders used in these mobile units must be isolated from the outside environment and, in particular, from the dust collected in the vacuum. Aluminum dust, once stored, can explode in the presence of a spark (from an electric motor, for example). Such isolation is relatively complex and expensive to implement. Consequently, the cost of these sanders is very high, which is a major obstacle to their widespread use. Furthermore, in body shops, mobile sanding equipment is often poorly maintained. Fine particles therefore clog the collection bag and any filters, quickly impairing the dust extraction. In addition, the weight of the electric sander is relatively high, which negatively impacts its ergonomics.

[0006] Thus, in general, body shops use pneumatic sanders since these are lightweight, easy to handle, and pose no risk in the presence of aluminum particles. Pneumatic sanders are usually connected to a dust extraction system, which is itself connected to a compressed air network installed in the body shop. Therefore, both the pneumatic sander and the dust extraction system are connected to the compressed air network of the body shop.

[0007] One drawback of this solution lies in the fact that, in order to obtain optimal operation of the pneumatic sander and suction device, it is necessary to... It is necessary to supply air at a very high pressure, around 7 bar. However, this very high air consumption by the sander and the dust extraction system can cause disruptions to the entire compressed air network. This can lead to variations in airflow to other tools in the room and result in quality problems, for example, in the case of a pneumatic paint sprayer connected to the same network.

[0008] Automatic start-up and stop devices for the dust extraction system have been proposed, depending on whether the sander is activated or not, in order to minimize these disturbances. However, the structure of these devices is complex and incorporates numerous components.

[0009] Since current solutions are not satisfactory, there is therefore a need to provide a new suction solution which allows optimal operation of the suction device when used with a pneumatic sander (or any other pneumatic tool) on a compressed air supply network, without disturbing the latter. Summary of the invention

[0010] The technique of the invention makes it possible to resolve at least some of the drawbacks raised by the prior art.

[0011] More specifically, the invention relates to a pneumatic sander, particularly for use in automotive body shops, comprising a pneumatic dust extraction device for sanding and a module for connecting the sander and the extraction device to a compressed air source, said connection module comprising:

[0012] - an internal duct having an air inlet connected to a compressed air source,

[0013] - a first air outlet supplying air to the sander (pilot supply) and arranged in communication with the air intake via a first air passage,

[0014] - a second air outlet supplying air to the dust extraction device sanding and arranged in communication with the air intake via a second air passage,

[0015] - a movable shutter mounted in the internal conduit, said movable shutter being in rest position, when said sander is stopped, and forced by a spring element to at least partially close the first air passage and the second air passage,

[0016] said connection module being configured for:

[0017] - when the sander is switched on, said compressed air source delivers compressed air in said first air passage to force said movable shutter against said spring element so as to open the first air passage and allow the compressed air to pass from the air inlet to the first air outlet and then to said sander, and at the same time to open the second air passage to allow compressed air to pass to said motor of said suction device, causing said suction device to suck up the dust from said sander;

[0018] - when said sander is stopped, said spring element forces said shutter mobile towards its resting position.

[0019] The invention therefore proposes a simple, purely pneumatic mechanism which allows the suction to be started when the sander is used.

[0020] In other words, the pneumatic vacuum cleaner is designed to have an automatic start and stop mode depending on whether the sander is switched on or off. The main advantage is a reduction in compressed air consumption while maintaining optimal vacuum performance and excellent suction performance without the use of any electrical components or parts.

[0021] The disturbances caused on the overall compressed air supply network of the workshop by the operation of the dust extraction device are limited.

[0022] The invention thus provides a suction solution particularly suited to the extraction of dust, and in particular aluminum dust. Furthermore, the pneumatic suction device according to the invention complies with the ATEX standard, a standard which must be observed, in particular, in automotive body shops. The suction device according to the invention therefore allows for safe use in certain hazardous / critical environments.

[0023] Thus, the invention proposes a new and inventive approach to solving the disadvantages of the prior art by providing a simple-to-implement suction solution offering high suction performance for optimal air consumption.

[0024] According to a particular aspect of the invention, said movable shutter comprises a first part that closes the second air passage to the vacuum cleaner when said sander is stopped, said first part being extended by a second part connected to the spring element and comprising a hemispherical element that comes substantially into contact with an inner wall of the internal duct to at least partially close the first air passage to the sander, the first air passage extending into an internal channel of the first part, so that, when the sander is switched on,The airflow from the air inlet flows into the internal channel towards the concave face of the hemispherical element to move said hemispherical element of the movable shutter away from the inner wall of the internal duct and allow the airflow to pass on one side towards the first air outlet communicating with the sander and on the other side towards the second air outlet communicating with the pneumatic vacuum cleaner.

[0025] Advantageously, the first part of the movable obturator includes at least one orifice for the passage of the airflow from the internal channel to the concave face of the hemispherical-shaped element.

[0026] Advantageously, the spring element connected to the second part of the movable shutter is fixed to a wall of the internal duct so as to force the movement of the movable shutter towards the air inlet and the second air outlet when the sander is not running.

[0027] According to a particular aspect of the invention, a manual operating member allows the movable shutter to be moved within the internal conduit from its rest position to a position allowing the passage of the airflow from the air inlet to the second air outlet communicating with the pneumatic vacuum cleaner.

[0028] The invention also relates to a connecting module for a sander as described above.

[0029] The invention further relates to an installation comprising a global compressed air supply network including at least one sander as described above. List of Figures

[0030] The invention, and its various advantages, will be more easily understood in light of the following description of an illustrative and non-limiting embodiment thereof, and the accompanying drawings, among which:

[0031] [Fig-1] is a cross-sectional view of a pneumatic fitting module implemented in a sander according to the invention when the latter is not in operation;

[0032] [Fig.2] is a detail view of part of the module of [Fig.1];

[0033] [Fig.3] is a cross-sectional view of the module of [Fig.1] when the sander is in operation operation;

[0034] [Fig.4] is a cross-sectional view of the module of [Fig.1] schematically showing the manual activation of the module. Detailed description of the invention

[0035] The invention relates to a pneumatic sander, particularly for automotive bodywork workshops, comprising a sanding dust extraction device and a module for connecting the sander and the extraction device to a compressed air source, allowing the automatic start-up and stop-down of the extraction device depending on whether the sander is activated (or in operation) or deactivated (stopped) respectively.

[0036] Fig. 1 is a cross-sectional view of the pneumatic connection module 1 of such a pneumatic sander in the resting state, i.e. when the sander is not in operation.

[0037] The sanding dust extraction device comprises a compressed air motor and a sanding dust collection volume (not shown). The sanding machine is powered by a compressed air motor and comprises one or more sanding elements (not shown).

[0038] The connection module 1 comprises a body 11, for example made of a metallic or plastic material. The body 11 can be machined / formed at one end to have an air inlet 13 for connection to a compressed air source. This source corresponds to the compressed air network supplying the entire workshop, the inlet air pressure being, for example, on the order of 7 bar or less. The air inlet 13 takes the form of a cylindrical housing for connection with a compressed air supply hose. The body 11 has, at a second end opposite the first end, a first air outlet 14 for supplying air to a sander ("pilot supply"). This first air outlet 14 takes the form of a cylindrical housing for connection with a hose connected to the sander. An internal air duct 16 of straight and cylindrical shape extends in the body 11 between the air inlet 13 and the first air outlet 14.A second air outlet 15, located near the air inlet 13, opens into the internal air duct 16 and is intended to supply air to the pneumatic vacuum cleaner ("pilot-controlled supply"). This second air outlet 15 takes the form of a cylindrical housing for connection with a hose connected to the pneumatic vacuum cleaner.

[0039] A first air passage A is defined between the air inlet 13 and the first air outlet 14. A second air passage B is defined between the air inlet 13 and the second air outlet 15.

[0040] Thus, the first air outlet 14 is arranged in communication with the air inlet 13 by the first air passage A, and the second air outlet 15 is arranged in communication with the air inlet 13 by the second air passage B.

[0041] A movable shutter 10 is mounted in the internal conduit 16, and is forced by a spring element 17 into the rest position ([Fig.l]) to at least partially close the first air passage A and the second air passage B when the sander is not in operation.

[0042] The internal conduit 16 has several successive cylindrical portions of distinct sections.

[0043] As illustrated in [Fig. 2], the movable shutter 10 comprises a first cylindrical portion 101 of variable cross-section that closes the second air passage to the vacuum cleaner when the sander is stopped by the spring element 17. [Fig. 2] shows that in this rest position, the airflow from the air inlet 13 cannot pass between the inner wall of the internal duct 16 and the outer wall of the first cylindrical portion 101 of the movable shutter 10 to the second outlet. air 15. The beveled end of the first part 101 is pressed against the wall of the air inlet 13 and carries a peripheral sealing gasket 18 which prevents air from entering the internal conduit 16 towards the vacuum cleaner.

[0044] The first part 101 of the movable shutter 10 is extended by a second part 102 connected to one end of the spring element 17 which extends along the longitudinal axis of the internal conduit 16, the other end of the spring element 17 being attached to an inner wall of the internal conduit 16 at the level of the first air outlet 14 communicating with the vacuum cleaner.

[0045] The first part of the obturator element has on the periphery of its other longitudinal end a second circular sealing gasket ensuring sealing with the internal walls of the internal conduit 16.

[0046] The second part 102 of the movable shutter 10 comprises a cylindrical core 102A around which extends a hemispherical (or parachute-shaped) element 102B, the peripheral edge of which comes substantially into contact with an inner wall of the internal duct 16 to at least partially close the first air passage to the sander. In this rest position of the movable shutter 10 (Figures 1 and 2), the diameter of the hemispherical element 102B is slightly smaller than the inner diameter of the internal duct 16, allowing a slight passage of air to the second air outlet 15 communicating with the sander. At rest, the airflow of the first air passage A is insufficient to counteract the force of the spring element 17 and move the movable shutter.

[0047] The first air passage A, defined between the air inlet 13 and the first air outlet 14, extends initially into a cylindrical internal channel 101A formed in the center of the first part 101 of the movable shutter 10. When the sander is switched on, the air inlet 13, which is connected to the overall compressed air supply network, provides a pressurized incoming airflow that flows into the internal channel 101A, then into the internal conduit 16 through air passage orifices 101B (connecting the internal channel 101A to the internal conduit 16) which are formed at the interface between the first part 101 and the second part 102 of the movable shutter 10. These air passage orifices 101B open into the internal conduit 16, so that the incoming airflow is directed towards the concave face of the hemispherical element 102B.When the airflow rate within the first air passage is sufficient to counteract the force of the spring element 17, the airflow displaces the hemispherical element 102B from left to right in the figures, and thus the movable shutter 10, to the position illustrated in [Fig. 3]. In this position, the hemispherical element 102B is no longer in contact with the inner wall of the internal duct 16, and the airflow from the passage orifices 101B can therefore bypass the movable shutter 10 and flow towards the air outlet 14 communicating with the . sander. The first air passage at this point is labeled A'. Simultaneously, as shown in [Fig. 3], the beveled end of the first part 101 is no longer pressed against the wall of the air inlet 13, so that part of the incoming airflow from the first air outlet 13 can enter the second air passage towards the second air outlet 15, which connects to the pneumatic vacuum cleaner. In the position of the movable shutter 10 in [Fig. 3], the incoming compressed airflow is directed on one side towards the sander via the first air passage A' and on the other side towards the motor of the pneumatic vacuum cleaner via the second air passage B, the latter then being able to collect dust from the sander.

[0048] Thus, when the sander is switched on, the pneumatic vacuum cleaner is also switched on by means of a simple design and purely mechanical mechanism.

[0049] It is understood that when the operation of the sander is interrupted (sander stopped), the spring element 17, acting as a return spring, moves the movable shutter 10 to the left, which at least partially closes the first air passage and closes the second air passage, thus cutting off the compressed air supply to the pneumatic vacuum cleaner motor. Consequently, the pneumatic vacuum cleaner switches off almost simultaneously. The movable shutter 10 then returns to its rest position.

[0050] The airflows within the connection module 1 are schematically illustrated by arrows in Figures 1 to 3.

[0051] To summarize, [Fig.1] illustrates the connecting module in the rest state of the movable shutter 10.

[0052] The air inlet or outlet 13 is connected to the compressed air (pressurized) network. With the sander not in use, the pressure is distributed throughout the system. There is a gap between the movable shutter 10 and the inner wall of the internal duct 16, which allows air to pass through (first air passage A). Under the action of the spring element 17, the movable shutter 10, acting as a slide valve, closes the second air passage to the pneumatic vacuum cleaner.

[0053] When the sander is switched on, the compressed air supply delivers compressed air through the first air passage to force the movable shutter 10 against the spring element 17, thereby further opening the first air passage A' and allowing compressed air to flow from the air inlet 13 to the first air outlet 14 and then to the sander. Simultaneously, it opens the second air passage B, allowing compressed air to flow to the motor of the pneumatic vacuum cleaner, causing the vacuum cleaner to collect dust from the sander. Figure 3 illustrates the automatic activation of the vacuum cleaner when the sander is switched on. In this scenario, the sander consumes compressed air (increasing the air flow rate). Air from the air inlet 13 enters the first air passage A and flows through the internal channel 101A. It then passes into the internal duct 16 via the air passage orifices 101B connecting the internal channel 101A to the internal duct 16. When the airflow is sufficient to counteract the force of the spring element 17 and move the hemispherical element 102B, the movable shutter 10 moves to the right (i.e., towards the first air outlet 14). The diameter of the hemispherical element is smaller than the internal diameter of the internal duct, so the compressed air flows at a higher rate towards the first outlet 14, which connects to the sander. In addition, the second air passage B is no longer closed by the movable shutter 10 and the incoming airflow can also pass from the air inlet 13 to the second air outlet 15.

[0054] Figure 4 illustrates the manual opening of the second air passage to the vacuum cleaner. To do this, the connection module 1 is equipped with a lever, or manual operating member, 12. By rotating the lever 12, a cam 121 moves the movable shutter 10 to the right, away from the air inlet 13. As a result, the compressed air flow from the air inlet 13 can pass to the second air outlet 15 via the second air passage B'.

[0055] Adjustment means (for example a screw) for the force of the spring element 17 forming a return spring may be provided.

[0056] The spring element can be a spiral spring or any other type of spring, or even a mechanical part made of a specific material.

Claims

Demands

1. A pneumatic sander, particularly for use in automotive body shops, comprising a pneumatic dust extraction device for sanding dust and a connection module (1) for connecting the sander and the dust extraction device to a compressed air source, said connection module (1) comprising: - an internal duct (16) having an air inlet (13) connected to a compressed air source, - a first air outlet (14) supplying air to the sander and arranged in communication with the air inlet (14) by a first air passage (A, A'), - a second air outlet (15) supplying air to the sanding dust extraction device and connected to the air inlet (13) by a second air passage (B), - a movable shutter (10) mounted in the internal duct (16), said movable shutter (10) being in the rest position when said sander is stopped, and forced by a spring element (17) to at least partially close the first air passage (A) and the second air passage (B), said connection module (1) being configured to: - when the sander is switched on, said compressed air source delivers a flow of compressed air into said first air passage (A, A') to force said movable shutter (10) against said spring element (17) so as to open the first air passage (A, A') and allow the air flow to pass from the air inlet (13) to the first air outlet (14) and then to said sander, and at the same time to open the second air passage (B) to allow the air flow to pass to said motor of said suction device, causing said suction device to suck up the dust from said sander; - when said sander is stopped, said spring element (17) forces said movable shutter (10) towards its rest position.

2. Sander according to claim 1, characterized in that said movable shutter (10) comprises: a first part (101) closing the second air passage (B) to the vacuum cleaner when said sander is stopped, said first part (101) being extended by a second part (102) connected to the spring element (17) and comprising a hemispherical element (102B) coming substantially into contact with an inner wall of the internal duct (16) to close at least partially the first air passage (A, A') to the sander, the first air passage (A, A') extending in an internal channel (101A) of the first part (101), so that, when the sander is switched on, the airflow from the air inlet (13) flows into the internal channel (101A) towards the concave face of the hemispherical element (102B) to move said hemispherical element (102B) of the movable shutter (10) away from the inner wall of the internal duct (16) and allow the airflow to pass on one side towards the first air outlet (14) communicating with the sander and on the other side towards the second air outlet (15) communicating with the pneumatic vacuum cleaner.

3. Sander according to claim 2, characterized in that the first part (101) of the movable shutter (10) includes at least one orifice (101B) for the passage of the airflow from the internal channel (101A) to the concave face of the hemispherical-shaped element (102B).

4. Sander according to claim 2 or 3, characterized in that the spring element (17) connected to the second part (102) of the movable shutter (10) is fixed on a wall of the internal conduit (16) so as to force the movement of the movable shutter towards the air inlet (13) and the second air outlet (15) when the sander is not running.

5. Sander according to any one of the preceding claims, characterized in that a manual operating member allows the movable shutter to be moved within the internal conduit (16) from its rest position to a position allowing the passage of the airflow from the air inlet (13) to the second air outlet (15) communicating with the pneumatic vacuum cleaner.

6. Connection module intended to be implemented in a pneumatic sander according to any one of claims 1 to 5.

7. Installation comprising a global compressed air supply network including at least one pneumatic sander according to any one of claims 1 to 5.

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