Leaf blower with internal combustion engine to limit the inhalation of harmful gases

Abstract

The invention relates to an exhaust gas transfer device (1) from an exhaust outlet to a blower nozzle, comprising: - a conduit (2) with a cross-section of at least 25 cm² having a first end (21) having a male end (23) and a second end (22) having a female end (24), the male end (23) having a shape complementary to that of the female end (24); - a tube (3) connected to the conduit (2) between its first and second ends (21, 22) and extending outward from the conduit between a proximal end (31), the tube (3) having a distal end (32) configured to connect to an exhaust pipe.

Description

Title of the invention: Leaf blower with internal combustion engine for limiting the breathing of harmful gases

[0001] The invention relates to handheld leaf blowers, and in particular to handheld leaf blowers generating an airflow from a drive by an internal combustion engine.

[0002] Handheld leaf blowers are frequently used by landscapers. Such blowers are particularly effective at clearing leaves or debris and concentrating them in a particular location. The airflow of the blowers is obtained from a blower, propelling air into a flexible nozzle operated by the user. The blower is generally driven in rotation by either a battery-powered electric motor or an internal combustion engine. For professional use, batteries have a reduced autonomy. Professionals must therefore keep a large number of batteries charged to be able to complete the job satisfactorily. Thus, a large number of professionals prefer to use internal combustion engine-driven blowers rather than electric-driven blowers.

[0003] Internal combustion engine blowers are generally carried by means of straps and are placed on the user's back. The internal combustion engine thus discharges its exhaust gases onto the user's back. In addition, work is generally carried out with the user's back to the wind, which means that the user is then positioned in the exhaust gas flow. For professionals, the duration of use is important and exhaust gases laden with unburned fuel or harmful gases are particularly harmful to their health.

[0004] The invention aims to solve one or more of these drawbacks. The invention thus relates to a device for transferring exhaust gas from an exhaust outlet to a blowing nozzle, characterized in that it comprises: - a conduit with a cross-section of at least 25 cm2 having a first end comprising a male end and a second end having a female end, the male end having a shape complementary to that of the female end; -a tube connected to the conduit between its first and second ends and extending projecting from the conduit by a proximal end, the tube having a distal end configured to connect to an exhaust pipe.

[0005] The invention also relates to the following variants. Those skilled in the art will understand that each of the features of the following variants can be independently combined with the above features, without constituting an intermediate generalization. Other characteristics and advantages of the invention will emerge clearly from the description given below, for information purposes only and in no way limiting, with reference to the appended drawings, in which:

[0006] According to a variant, the device further comprises a helical spring surrounding the tube.

[0007] According to another variant, the device comprises an openwork sheath made of braided fibers surrounding the helical spring.

[0008] According to another variant, the device comprises shims inserted between the tube and the spring.

[0009] According to yet another variant, the conduit has a metal interface for connection with the tube.

[0010] According to a variant, the conduit is made of metal between the first and second ends.

[0011] According to another variant, the conduit has a length, between its first and second ends, of between 30 and 200 mm.

[0012] According to yet another variant, the tube has a length of at least 250 mm.

[0013] The invention also relates to a portable leaf blower, comprising: -a blower; -an internal combustion engine configured to drive the fan to rotate, the internal combustion engine having an exhaust pipe; - an exhaust gas transfer device as defined above; -a blower air outlet duct connected to one of the male end and the female end of the exhaust gas transfer device duct; -a nozzle connected to the other of the male end piece and the female end piece, the distal end of the tube being connected to the exhaust pipe of the internal combustion engine.

[0014] According to a variant, the air outlet duct has a shape complementary to one of the male end piece and the female end piece, and the air outlet duct and one of the male end piece and the female end piece are configured to allow rotation relative to each other.

[0015] [Fig-1] is a side sectional view of an exemplary embodiment of an exhaust gas transfer device according to the invention;

[0016] [Fig.2] is a side sectional view of a conduit of the device of [Fig.l] associated with elements of a blower;

[0017] [Fig.3] is a side sectional view of a tube according to [Fig.l] connected to an exhaust pipe of a blower;

[0018] [Fig.4] illustrates a handheld leaf blower including an exhaust gas transfer device according to [Fig.l].

[0019] [Fig.l] is a side sectional view of an exemplary embodiment of an exhaust gas transfer device 1. [Fig.2] is a side sectional view of the device 1 about to be assembled to a blower. The device 1 is intended to transfer exhaust gases from an exhaust outlet 93 to a blower nozzle 95, as illustrated for the blower 9 in [Fig. 4]. For the sake of readability, some components of the device 1 are not illustrated in [Fig. 4]. The device 1 comprises a conduit 2 and a tube 3.

[0020] The conduit 2 has a cross-section of at least 25 cm2 (and generally at most 120 cm2). The conduit 2 has a first end 21 comprising a male end piece 23 and a second end 22 having a female end piece 24, the male end piece 23 having a shape complementary to that of the female end piece 24.

[0021] The tube 3 is connected to the conduit 2 between its first and second ends 21 and 22. The tube 3 projects from the conduit 2 by a proximal end 31. The tube 3 has a distal end 32 configured to connect to an exhaust pipe 93 of the blower 9.

[0022] The duct 2 makes it possible to ensure continuity between an air outlet 94 of the blower 9 supplied with compressed air by a blower, and one end of the blowing nozzle 95. Since the first end 21 has a shape complementary to that of the second end 22, the duct 2 can fit into the air outlet 94 replacing the nozzle 95 and fit with the nozzle 95 replacing the air outlet 94. The duct 2 can thus be associated with the blower 9 without altering the air flow through the blowing nozzle 95 and without requiring modification of the parts of the blower 9. Furthermore, due to a cross-section of at least 25 cm2, the duct 2 makes it possible not to induce an excessive pressure drop towards the nozzle 95.

[0023] The tube 3 makes it possible to recover the gases at the outlet of the exhaust pipe 93 to conduct them into the conduit 2. The exhaust gases are then carried to the outlet of the nozzle 95 by means of the compressed air leaving the blower of the blower 9. Thus, harmful exhaust gases are expelled at a distance and in front of the blower 9 (and therefore generally in the direction of the wind and away from the user's back) and thus do not risk poisoning the user.

[0024] Furthermore, the conduit 2 can form a fixed part relative to the air outlet 94, which makes it possible not to have to deform the tube 3 during use.

[0025] In operation, the tube 3 is crossed by the exhaust gases and may have a high temperature. Advantageously, to avoid burning the user, the exhaust gas transfer device 1 further comprises a helical spring 4 surrounding the tube 3. The spring 4 can both follow a curvilinear shape of the tube 3 and provide air passages towards the tube 3, promoting its cooling. The spring 4 thus has a temperature lower than that of the tube 3, limiting the risk of burning the user.

[0026] Advantageously, to more effectively protect the user from a burn by contact with the tube 3, the exhaust gas transfer device 1 comprises a sheath 5. The sheath 5 surrounds the helical spring 4, to prevent contact of the user with the spring 4. Thus, the temperature of the sheath 5 is lower than that of the tube 3 and the spring 4.

[0027] Advantageously, to promote cooling of the tube 3, the sheath 5 is an openwork sheath made of braided fibers, so that an air flow can pass through it and thus allow cooling of the tube 3. It is thus possible to reduce the temperature of the tube 3 at its ends 31 and 32 and reduce the contact temperature of the user with the sheath 5.

[0028] Advantageously, the exhaust gas transfer device 1 comprises wedges 6 inserted between the tube 3 and the spring 4. The wedges 6 make it possible to create a radial distance between the tube 3 and the spring 4. This makes it possible to provide a cooling space between the tube 3 and the spring 4 and to reduce the temperature at the spring 4, thus reducing the risk of burning. The wedges 6 may have an annular shape. The wedges 6 may be immobilized on the tube 3 by welding or by high-temperature bonding. The wedges 6 may be distributed along the length of the tube 3 to ensure a space between the tube 3 and the spring 4 along their length.

[0029] Advantageously, the exhaust gas transfer device 1 comprises wedges 6 inserted between the tube 3 and the spring 4 making it possible to maintain a spacing between them of between 5 and 15 mm.

[0030] The exhaust gas transfer device 1 must advantageously withstand high temperatures. In particular, it must be avoided that the conduit 2 is confronted with deformations or degradation due to the temperature of the exhaust gases introduced therein. Advantageously, to more effectively withstand a high temperature, the exhaust gas transfer device 1 comprises a conduit 2 having a metal interface arranged between the ends 21 and 22, for connection with the tube 3 (for example by a screwed assembly). In the example illustrated in [Fig.l] and 2, the conduit 2 is provided with a metal insert 25 making it possible to connect the end 31 of the tube 3. The insert 25 is here in the form of a tube provided with a collar, the collar being pressed against the internal surface of the conduit 2. Such a metal interface can for example be made from nickel, steel, chromium, titanium or aluminum.

[0031] An insert 25 proves to be particularly advantageous if the conduit 2 is made of synthetic or plastic material. It is also possible to envisage that the metal interface is made in one piece with the conduit 2, for example by molding.

[0032] Advantageously, the exhaust gas transfer device 1 comprises a conduit 2 having a length, between its first and second ends 21 and 22, of between 30 and 200 mm. Such a length facilitates both the connection with the tube 3 and allows not to alter the ergonomics by not lowering the nozzle 95 excessively.

[0033] In order to guarantee a sufficient distance between the exhaust pipe 93 and the conduit 2, the tube 3 advantageously has a length of at least 250 mm.

[0034] The device 1 is advantageously associated with a portable blower 9, comprising a blower and an internal combustion engine 92 provided with an exhaust pipe 93. The internal combustion engine is configured to drive the blower 91 in rotation. The air outlet duct 94 receives the air compressed by the blower and is connected to a complementary end piece of an exhaust gas transfer device 1. The other end piece of the device 1 is connected to a nozzle 95.

[0035] Advantageously, the blower 9 has an air outlet duct 94 having a shape complementary to the duct 2 and allowing rotation of the duct 2 relative to the air outlet duct 94. Thus, the user can orient the nozzle 95 in a desired direction without inducing excessive forces on the duct 2.

Claims

Claims

1. Exhaust gas transfer device (1) from an exhaust outlet to a blower nozzle, characterized in that it comprises: - a conduit (2) with a cross section of at least 25 cm2 having a first end (21) comprising a male end piece (23) and a second end (22) having a female end piece (24), the male end piece (23) having a shape complementary to that of the female end piece (24); - a tube (3) connected to the conduit (2) between its first and second ends (21, 22) and extending projecting from the conduit (2) by a proximal end (31), the tube (3) having a distal end (32) configured to connect to an exhaust pipe (93).

2. An exhaust gas transfer device (1) according to claim 1, further comprising a coil spring (4) encircling the tube (3).

3. Exhaust gas transfer device (1) according to claim 2, comprising a perforated sheath (5) made of braided fibers surrounding the helical spring (4).

4. Exhaust gas transfer device (1) according to claim 2 or 3, comprising interposed shims (6) between the tube (3) and the spring (4).

5. An exhaust gas transfer device (1) according to any preceding claim, wherein said conduit (2) has a metal interface (25) for connection with the tube (3).

6. An exhaust gas transfer device (1) according to claim 5, wherein said conduit (2) is made of metal between the first and second ends (21, 22).

7. An exhaust gas transfer device (1) according to any preceding claim, wherein the conduit (2) has a length, between its first and second ends, of between 30 and 200mm.

8. An exhaust gas transfer device (1) according to any preceding claim, wherein the tube (3) has a length of at least 250mm.

9. Portable leaf blower (9), comprising: - a blower (91); - an internal combustion engine (92) configured to drive the rotating blower (91), the internal combustion engine (92) comprising an exhaust pipe (93); - an exhaust gas transfer device (1) according to any one of the preceding claims; -an air outlet duct (94) of the blower (91) connected to one of the male end and the female end of the duct (2) of the exhaust gas transfer device (1); -a nozzle (95) connected to the other of the male end piece and the female end piece, the distal end of the tube (3) being connected to the exhaust pipe of the internal combustion engine.

10. The handheld leaf blower (9) of claim 9, wherein the air outlet duct (94) has a shape complementary to one of the male end piece and the female end piece, and wherein the air outlet duct (94) and one of the male end piece and the female end piece are configured to allow rotation relative to each other.

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