GB2083733A

GB2083733A - Casing for a lawn mower

Info

Publication number: GB2083733A
Application number: GB8123065A
Authority: GB
Original assignee: Bernard Moteurs SA
Current assignee: Bernard Moteurs SA
Priority date: 1980-09-23
Filing date: 1981-07-27
Publication date: 1982-03-31
Also published as: FR2490451B2; FR2490451A2

Abstract

A plastics casing for a lawn mower, comprises a double walled hollow body, which walls include an upper wall and a well wall (3) for together at least partially covering and housing drive means (40) for a cutter blade (8), and a lower wall shaped to provide a cover for the cutter blade (8), a suction volute (14) for directing cut grass and a nozzle for ejecting cut grass. The casing (2) includes a cover member (5) for sealingly covering the upper end of the opening defined by the well wall (3). The lower wall has a cooling air intake aperture (12) and the upper wall has a cooling air outlet aperture (15). The apertures (12, 15) communicate with one another so that air is passed from outside the casing through the hollow body between the walls thereof and along the inside surface of the cover member (5) to the well wall aperture via the aperture (12), aperture (15) and cover member inside surface. The cover member (5) is also of double wall hollow form provided with cooling air orifices (7, 9) for communication with the apertures (12, 15). <IMAGE>

Description

SPECIFICATION Casing for a lawn mower This invention relates to a plastics casing for a lawn mower comprising a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass. The double-walled hollow body may contain sound absorbing material between the walls. Such a casing is described in our copending Application No. 7923071 filed on 3rd July, 1979.

It is difficult to provide an electric lawn mower with good insulation, particularly because such a mower is sensitive to moisture. This is because conventionally the air for cooling the electric motor is circulated around the motor between an upper cover member, which covers the motor, and a lower part of the casing.

Thus, water splashing into the mower from out side can pass into the motor. The conventional method of cooling therefore makes it practically impossible to use electric motors without sufficient protection.

There is thus a need for a generally improved lawn mower casing which reduces problems of insulation which occur on simultaneous introduction of water and cooling air in the casing.

According to the invention there is provided a plastics casing for a lawn mower, comprising a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass, wherein the casing includes a double walled hollow cover member for sealingly covering the upper end of the opening defined by the well wall, which cover member has at least one air intake orifice and at least one cooling air delivery orifice, and wherein the lower wall has at least one cooling air intake aperture and the upper wall has at least one cooling air outlet aperture, the cooling air orifices and apertures communicating with one another so that cooling air can be passed from outside the casing through the hollow body between the walls thereof and along the inside surface of the cover member, to the well wall aperture, via the lower wall intake aperture, the upper wall outlet aperture, the cover member intake orifice, the inside surface of the cover member, and the cover member delivery orifice.

Such a casing permits cooling air to be drawn into and discharged from the lawn mower below the casing, in a region which is not subject to water splashing.

It should be noted that the length of the cooling air flow path substantially prevents water penetrating into a motor for driving the cutting blade or blades, and into a housing for the motor.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure lisa view of a casing of the invention in longitudinal vertical section, and Figure 2 is a view of the casing of Figure 1 in vertical cross-section.

A plastics casing 2 of the invention shown in the drawings comprises a double walled hollow body provided with a well wall 3 defining an aperture. The well wall 3 forms a housing for drive means 4 which more particularly comprises an electric motor 40 above which is mounted a fan 41, while the shaft 42 of the motor drives a cutting blade 8.The well wall aperture 3 is sealingly covered by a cover member 5, which preferably is double walled, the lower wall 51 of which carries a peripheral seal 6 and is apertured with at least one air intake orifice 7 and a delivery orifice 9 which provides for a flow of cooling air along the inside surface of the cover member 5 towards the aperture defined by the well wall 3 in which it is channelled to outlets 10 which are provided on a carrier plate 11 for the motor 40, which carrier plate closes the bottom of the aperture in the well wall 3.

At least one cooling air intake aperture 12 is provided in the lower wall of the casing, near the location of the volute 14, and is closed by a screen member 13 to prevent pieces of cut grass from being sucked in. In operation a reduced pressure is created in the internal volume V of the casing, and the air escapes from the interior of the casing to the cover member 5 via at least one cooling air outlet aperture 15 provided in an upper wall of the casing 2.

This arrangement therefore provides for a free flow of cooling air between the casing walls through the apertures 12 and 15 and the orifices 7 and 9, as shown by the circuit illustrated by arrows in Figure 1.

It should be noted that a reduced pressure occurs in the interior of the casing, while an increased pressure occurs in the aperture in the well wall 3.

1. Aplasticscasingfora lawn mower,compris- ing a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall, shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass, wherein the casing includes a double walled hollow cover member for sealingly covering the upper end of the opening defined by the well wall, which cover member has at least one air intake orifice and at least one cooling air delivery orifice, and wherein the lower wall has at least one cooling air intake aperture and the upper wall has at least one cooling air outlet aperture, the cooling air orifices and apertures communicating with one another so that cooling air can be passed from outside the casing through the hollow body between

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Casing for a lawn mower This invention relates to a plastics casing for a lawn mower comprising a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass. The double-walled hollow body may contain sound absorbing material between the walls. Such a casing is described in our copending Application No. 7923071 filed on 3rd July, 1979. It is difficult to provide an electric lawn mower with good insulation, particularly because such a mower is sensitive to moisture. This is because conventionally the air for cooling the electric motor is circulated around the motor between an upper cover member, which covers the motor, and a lower part of the casing. Thus, water splashing into the mower from out side can pass into the motor. The conventional method of cooling therefore makes it practically impossible to use electric motors without sufficient protection. There is thus a need for a generally improved lawn mower casing which reduces problems of insulation which occur on simultaneous introduction of water and cooling air in the casing. According to the invention there is provided a plastics casing for a lawn mower, comprising a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass, wherein the casing includes a double walled hollow cover member for sealingly covering the upper end of the opening defined by the well wall, which cover member has at least one air intake orifice and at least one cooling air delivery orifice, and wherein the lower wall has at least one cooling air intake aperture and the upper wall has at least one cooling air outlet aperture, the cooling air orifices and apertures communicating with one another so that cooling air can be passed from outside the casing through the hollow body between the walls thereof and along the inside surface of the cover member, to the well wall aperture, via the lower wall intake aperture, the upper wall outlet aperture, the cover member intake orifice, the inside surface of the cover member, and the cover member delivery orifice. Such a casing permits cooling air to be drawn into and discharged from the lawn mower below the casing, in a region which is not subject to water splashing. It should be noted that the length of the cooling air flow path substantially prevents water penetrating into a motor for driving the cutting blade or blades, and into a housing for the motor. For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure lisa view of a casing of the invention in longitudinal vertical section, and Figure 2 is a view of the casing of Figure 1 in vertical cross-section. A plastics casing 2 of the invention shown in the drawings comprises a double walled hollow body provided with a well wall 3 defining an aperture. The well wall 3 forms a housing for drive means 4 which more particularly comprises an electric motor 40 above which is mounted a fan 41, while the shaft 42 of the motor drives a cutting blade 8.The well wall aperture 3 is sealingly covered by a cover member 5, which preferably is double walled, the lower wall 51 of which carries a peripheral seal 6 and is apertured with at least one air intake orifice 7 and a delivery orifice 9 which provides for a flow of cooling air along the inside surface of the cover member 5 towards the aperture defined by the well wall 3 in which it is channelled to outlets 10 which are provided on a carrier plate 11 for the motor 40, which carrier plate closes the bottom of the aperture in the well wall 3. At least one cooling air intake aperture 12 is provided in the lower wall of the casing, near the location of the volute 14, and is closed by a screen member 13 to prevent pieces of cut grass from being sucked in. In operation a reduced pressure is created in the internal volume V of the casing, and the air escapes from the interior of the casing to the cover member 5 via at least one cooling air outlet aperture 15 provided in an upper wall of the casing 2. This arrangement therefore provides for a free flow of cooling air between the casing walls through the apertures 12 and 15 and the orifices 7 and 9, as shown by the circuit illustrated by arrows in Figure 1. It should be noted that a reduced pressure occurs in the interior of the casing, while an increased pressure occurs in the aperture in the well wall 3. CLAIMS

1. Aplasticscasingfora lawn mower,compris- ing a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall, shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass, wherein the casing includes a double walled hollow cover member for sealingly covering the upper end of the opening defined by the well wall, which cover member has at least one air intake orifice and at least one cooling air delivery orifice, and wherein the lower wall has at least one cooling air intake aperture and the upper wall has at least one cooling air outlet aperture, the cooling air orifices and apertures communicating with one another so that cooling air can be passed from outside the casing through the hollow body between the walls thereof and along the inside surface of the cover member, to the well wall aperture, via the lower wall intake aperture, the upper wall outlet aperture, the cover member intake orifice, the inside surface of the cover member, and the cover member delivery orifice.

2. A plastics casing for a lawn mower, substantially as hereinbefore with reference to the accompanying drawings.

2. A casing according to claim 1, wherein the cover member has an inner wall which carries a periphery sealing means, which is provided with the air intake orifice for communication with the upper wall outlet aperture and which is provided with the delivery orifice for communication with the well wall aperture, air flowing, in operation of the casing, from the well wall aperture via air outlets provided on a carrier plateforthe drive means.

3. A plastics casing for a lawn mower, substantially as hereinbefore described with reference to the accompanying drawings.

New claims or amendments to claims filed on 18th December 1981 Superseded claims 1 to 3 New or amended claims:

1. A plastics casing for a lawn mower, comprising a double walled hollow body, which walls include an upper wall and a well wall for together at least partially covering and housing drive means for a cutter blade or blades, and a lower wall, shaped to provide a cover for the cutter blade or blades, when the latter is or are present, a suction volute for directing cut grass and a nozzle for ejecting cut grass, wherein the casing includes a double walled hollow cover member for sealingly covering the upper end of the opening defined by the well wall by engagement between a peripheral sealing means, carried on an inner wall of the cover member, and the upper end of the well wall, which innerwall of the cover member has at least one air intake orifice and at least one cooling air delivery orifice, and wherein the lower wall has at least one cooling air intake aperture located at the level of the suction volute and the upper wall has at least one cooling air outlet aperture, the cooling air orifices and apertures communicating with one another so that cooling air can be passed from outside the casing through the hollow body between the walls thereof and along the inside surface of the cover member, to the well wall aperture, via the lower wall intake aperture, the upper wall outlet aperture, the cover member intake orifice, the inside surface of the cover member and the cover member delivery orifice, and from the well wall aperture via air outlets provided on a carrier plate for the drive means.