GB2113327A - Ventilated brake drum - Google Patents

Abstract

A plurality of radially extending passages (16) are defined within the brake drum (10) so that upon rotation of same, air is forced to flow from within the brake drum and/or from outside of the drum out through the passages to cool same. <IMAGE>

Description

SPECIFICATION Ventilated brake drum The present invention relates generally to a brake drum and more specifically to a brake drum which is mounted on a vehicle such as a forklift and which is exposed to excessive heating.

In a previously proposed arrangement (shown in Fig. 1 of the drawings) which is suitable for use with an industrial vehicle such as a fork lift, a shoe brake arrangement has included a brake drum 1 which is removably mounted on a drive shaft 2 so as to be rotatable therewith. In order to dissipate the heat which tends to be rapidly generated by the frequent stop-start operation of a fork lift, finning 3 has been provided about the external periphery of the drum 1. However, even with the provision of the finning 3, still the temperature of the drum has risen excessively giving rise to rapid brake lining wear. This overheating problem has been further aggrevated when the brake drum has been, as shown, located immediately adjacent the vehicle motor 4 (such as an electric motor) which itself becomes heated during vehicle operation.

Accordingly, it is an object of the present invention to provide a brake drum which is simple in construction, has no moving parts and which is able to dissipate the heat generated by frequent brake application at a rate adequate to prevent excessive temperatures occurring.

More specifically the present invention takes the form of a brake drum for a vehicle wheel comprising a plurality of radially oriented passages which extend through the drum and through which air is forced to flow when the drum rotates.

The features and advantages of the arrangement of the present invention will become more clearly appreciated from the following description taken in conjunction with the accompanying drawings in which: Figure 1 is a sectional view showing the prior art arrangement discussed in the opening paragraphs of the present specification; Figure 2 is a sectional view showing a first embodiment of the present invention; Figure 3 is an isometric view of the arrangement shown in Fig. 2; and Figure 4 is a sectional view showing a second embodiment of the present invention.

Figs. 2 and 3 show a first embodiment of the present invention. In this arrangement a brake drum 10 is formed with a plurality of radially extending fin-like projections 1 2 on the circular outboard surface thereof. As shown, these projections 1 2 extend from the peripheral edge inwardly and terminate at a predetermined distance from the axis of rotation of the drum. An annular plate 1 4 is secured in place on the projections 1 2 via screws 1 3 and cooperates with same to define a plurality of radially extending passages 1 6.

The drum 10 is further formed with a plurality of apertures 1 8 which provide fluid communication between the interior 20 of the brake drum 10 and the passages 16.

With this arrangement, as the drum rotates the air in the passages is subject to a centrifugal force which induces the air to flow radially out of the passages 16. Simultaneously, fresh air is induced into the passages through an opening 22 defined within the annular plate 14 and through the apertures 18 formed in the drum 10. Accordingly, any air which is heated by contact with the brake linings (not shown) tends to be sucked out of the drum 10 while the drum per se is simultaneously cooled by the flow of air through the passages and over the fin-like projections.

It will be appreciated that the ventilating (and therefore the cooling) characteristics of the arrangement just disclosed may be controlled by varying the size of the fin like projections 12, the number of same, the diameter of the aperture 22 defined in the annular member 14 and the apertures 1 8 formed in the drum 10. It will be further appreciated that as long as the drum rotates air will be forced to flow through the passages and thus cool the drum. If so desired the annular plate may be omitted.

Fig. 4 shows a second embodiment of the present invention. In this arrangement, the drum is cast or otherwise suitably formed so that the structure defining the passages 1 6 is integral with the drum proper. In this arrangement air is exclusivelty fed into the passages through an annular opening 24 which fluidly interconnects the passages 1 6 and the interior of the drum 20.

1. A brake drum for a vehicle wheel comprising: a plurality of radially oriented passages which extend through said drum and through which air is forced to flow when said drum rotates.

2. A drum brake as claimed in claim 1, wherein said passages are defined by a plurality of radially extending fin-like projections formed on an external circular face of said drum and an annular plate which is secured to said fin-like projections.

3. A drum brake as claimed in claim 1, wherein said passages are formed integrally with said drum and communicate with the interior of said drum through an annular aperture.

4. A drum brake substantially as described with reference to Figs. 2 and 3, or Fig. 4 of the accompanying drawings.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ventilated brake drum The present invention relates generally to a brake drum and more specifically to a brake drum which is mounted on a vehicle such as a forklift and which is exposed to excessive heating. In a previously proposed arrangement (shown in Fig. 1 of the drawings) which is suitable for use with an industrial vehicle such as a fork lift, a shoe brake arrangement has included a brake drum 1 which is removably mounted on a drive shaft 2 so as to be rotatable therewith. In order to dissipate the heat which tends to be rapidly generated by the frequent stop-start operation of a fork lift, finning 3 has been provided about the external periphery of the drum 1. However, even with the provision of the finning 3, still the temperature of the drum has risen excessively giving rise to rapid brake lining wear. This overheating problem has been further aggrevated when the brake drum has been, as shown, located immediately adjacent the vehicle motor 4 (such as an electric motor) which itself becomes heated during vehicle operation. Accordingly, it is an object of the present invention to provide a brake drum which is simple in construction, has no moving parts and which is able to dissipate the heat generated by frequent brake application at a rate adequate to prevent excessive temperatures occurring. More specifically the present invention takes the form of a brake drum for a vehicle wheel comprising a plurality of radially oriented passages which extend through the drum and through which air is forced to flow when the drum rotates. The features and advantages of the arrangement of the present invention will become more clearly appreciated from the following description taken in conjunction with the accompanying drawings in which: Figure 1 is a sectional view showing the prior art arrangement discussed in the opening paragraphs of the present specification; Figure 2 is a sectional view showing a first embodiment of the present invention; Figure 3 is an isometric view of the arrangement shown in Fig. 2; and Figure 4 is a sectional view showing a second embodiment of the present invention. Figs. 2 and 3 show a first embodiment of the present invention. In this arrangement a brake drum 10 is formed with a plurality of radially extending fin-like projections 1 2 on the circular outboard surface thereof. As shown, these projections 1 2 extend from the peripheral edge inwardly and terminate at a predetermined distance from the axis of rotation of the drum. An annular plate 1 4 is secured in place on the projections 1 2 via screws 1 3 and cooperates with same to define a plurality of radially extending passages 1 6. The drum 10 is further formed with a plurality of apertures 1 8 which provide fluid communication between the interior 20 of the brake drum 10 and the passages 16. With this arrangement, as the drum rotates the air in the passages is subject to a centrifugal force which induces the air to flow radially out of the passages 16. Simultaneously, fresh air is induced into the passages through an opening 22 defined within the annular plate 14 and through the apertures 18 formed in the drum 10. Accordingly, any air which is heated by contact with the brake linings (not shown) tends to be sucked out of the drum 10 while the drum per se is simultaneously cooled by the flow of air through the passages and over the fin-like projections. It will be appreciated that the ventilating (and therefore the cooling) characteristics of the arrangement just disclosed may be controlled by varying the size of the fin like projections 12, the number of same, the diameter of the aperture 22 defined in the annular member 14 and the apertures 1 8 formed in the drum 10. It will be further appreciated that as long as the drum rotates air will be forced to flow through the passages and thus cool the drum. If so desired the annular plate may be omitted. Fig. 4 shows a second embodiment of the present invention. In this arrangement, the drum is cast or otherwise suitably formed so that the structure defining the passages 1 6 is integral with the drum proper. In this arrangement air is exclusivelty fed into the passages through an annular opening 24 which fluidly interconnects the passages 1 6 and the interior of the drum 20. CLAIMS

1. A brake drum for a vehicle wheel comprising: a plurality of radially oriented passages which extend through said drum and through which air is forced to flow when said drum rotates.

2. A drum brake as claimed in claim 1, wherein said passages are defined by a plurality of radially extending fin-like projections formed on an external circular face of said drum and an annular plate which is secured to said fin-like projections.

3. A drum brake as claimed in claim 1, wherein said passages are formed integrally with said drum and communicate with the interior of said drum through an annular aperture.

4. A drum brake substantially as described with reference to Figs. 2 and 3, or Fig. 4 of the accompanying drawings.