Removable power unit for load carrying vehicles such as golf caddies and a load carrying vehicle equipped with this power unit

The present invention provides a removable power unit for a load carrying vehicle such as a golf caddy, having a drive motor coupled to a reduction gear driving in rotation a drive shaft having a drive wheel at each of its ends, the drive shaft being formed of two shaft sections extending respectively on each side of the reduction gear, characterized in that at least one of the shaft sections is mounted for rotation inside a sleeve through a bearing inserted in this sleeve, this latter being secured by one of its ends to the casing of the reduction gear. It also relates to a load carrying vehicle equipped with such a power unit.

The present invention relates to a removable power unit for a load carrying 
vehicle such as a golf caddy, this unit including a drive motor coupled to 
a reduction gear causing rotation of a drive shaft having a drive wheel at 
each of its ends, said drive shaft being formed of two shaft sections 
extending respectively on each side of said reduction gear. 
Power units are already known for load carrying vehicles in which the drive 
shaft driven in rotation through a reduction gear is intended to be 
supported by one or more bearings permanently fixed to the chassis of the 
load carrying vehicle. 
This construction with one or two bearings permanently fixed to the chassis 
means that the power unit is also permanently fixed thereto, which 
requires precise alignment of the axis of the bearings of the reduction 
gear with the axis of the load carrying bearings and, therefore accurate 
machining of these latter. Furthermore, this or these bearings must be 
disposed side by side with the drive wheels so as to reduce or cancel out 
the cantilever thereof, which requires a large sized chassis. 
Furthermore, there lacks the possibility of rapid removal of the power unit 
from the chassis of the load carrying vehicle, as well as rapid standard 
exchange and/or repair of the power unit. 
Furthermore, the cost price of the assemblies is high because of the need 
for precise machining of the bearings supporting the drive wheels and 
because of the necessity of using a load carrying chassis of great width. 
The aim of the present invention is to overcome these drawbacks and for 
this it provides a power unit of the type defined in the first paragraph 
of this description which is characterized in that at least one of the 
shaft sections is rotatably mounted inside a sleeve by means of a bearing 
inserted in this sleeve, this latter being integrally secured by one of 
its ends to the reduction gear casing. 
The power unit thus described forms an independent unit and not permanently 
fixed to the load carrying vehicle which it is intended to equip with all 
the advantages that that entails. 
In accordance with the invention, the sleeve extends preferably to the 
immediate vicinity of the wheel carried by the shaft section inserted in 
said sleeve, the bearing being situated in the immediate vicinity of the 
free end of this sleeve. Thus, each bearing is simply inserted in the end 
of the sleeve without subsequent machining and with a negligible 
cantilever of the drive wheels, providing very easy rapid removal of the 
power unit from the chassis of the load carrying vehicle. The result is an 
appreciably reduced cost price of the assembly of the vehicle. 
In a first variant, the two shaft sections are of the same length in which 
case it is preferable for each section to be mounted rotatably in a sleeve 
equipped with its bearing. In this variant, the motor coupled to the 
reduction gear is placed substantially in the longitudinal axis of the 
chassis of the load carrying vehicle. In a second variant, the two shaft 
sections are of different lengths in which case it is preferable for only 
the longest shaft section to be mounted for rotation in a sleeve equipped 
with its bearing supporting one of the drive wheels, the bearings of the 
reduction gear then serving as support bearing for the other drive wheel. 
The reduction gear of the power unit of the invention may in particular be 
a worm gear. 
The wheel of the worm gear may more particularly be of the hollow shaft 
type, each shaft section then being hinged to this hollow shaft by a ball 
joint disposed in the hollow shaft and connected thereto by a drive means. 
The wheel of the worm gear may in a variant be of the solid shaft type, at 
least one of the shaft sections then being hinged to this solid shaft 
through a universal joint. 
The present invention relates moreover to a load carrying vehicle such as a 
golf caddy, having a chassis and being characterized in that it further 
includes the above described power unit, said chassis being provided with 
means for removably securing it to at least one sleeve of said power unit. 
These securing means may for example be formed by notches adapted for 
receiving said sleeve.

The load carrying vehicle, for example a golf caddy, shown in FIGS. 1 and 2 
includes, in a way known per se, a chassis 1 whose front part is connected 
by a rod 2 to a support 3 receiving the axis 4 of a non drive bearing 
wheel 5 of a diameter less than that of the drive wheels 10, 11, which 
will be discussed hereafter. 
This vehicle further includes, at the rear of the chassis, a power unit 
including an electric drive motor 6, fed by a battery 7 and coupled to a 
reduction gear 8 rotatably driving a drive shaft 9, each end of which is 
provided with a drive wheel 10, 11. This shaft 9 is formed of two shaft 
sections 12, 13 disposed respectively on each side of the reduction gear 
8. 
In accordance with the present invention, one at least of the shaft 
sections 12, 13 is mounted for rotation inside a sleeve. More precisely, 
in the embodiment illustrated in FIGS. 2, 4 and 5, the two sections 12, 13 
are of the same length and are mounted respectively for rotation inside 
sleeves 14, 15 by means of bearings 16, 17 inserted in said sleeves, these 
latter being fixed by one of their ends respectively to flanges 18, 19 
secured to the lateral parts of the casing 20 of the reduction gear 8. 
Furthermore, it will be noted that sleeves 14, 15 extend from said flanges 
to the immediate vicinity of wheels 10, 11, the bearings 16, 17, being 
situated in the immediate vicinity of the free end of said sleeves so that 
the wheels 10, 11 are supported by these bearings with a negligible 
cantilever with respect thereto. 
In the embodiment shown in FIG. 4, the reduction gear 8 includes a slow 
wheel 21 with hollow shaft 21a, driven by an endless screw 22 in direct 
engagement with the shaft of motor 6. This slow wheel 21 is mounted for 
rotation on casing 20 through two ball bearings 23, 24 and rotates the two 
shaft sections 12, 13, independent of each other, respectively through two 
ball joints 25, 26 mounted in the hollow shaft of wheel 21, carried 
respectively by the free end of each section 12, 13 and each having a 
drive finger 27, 28 fitting in a keying groove 29 provided on said hollow 
shaft 21a. 
In the embodiment shown in FIG. 5, the reduction gear 8 has the same 
structure as that of the reduction gear 8 shown in FIG. 4, except that the 
slow wheel 21 has a solid shaft 21b, this latter being driven in rotation 
by wheel 21 by means of a key 30. Furthermore, the ends of this solid 
shaft 21b are respectively in engagement with the free ends of shaft 
sections 12, 13 through universal joints 31, 32 outside the casing 20 of 
the reduction gear. 
As shown in FIGS. 3 and 6, the shaft sections 12, 13 may in a variant be of 
different lengths. In this embodiment, the reduction gear 8 has the same 
structure as that of the reduction gear 8 shown in FIG. 4, the shaft 
sections 12, 13 are connected together so as to form a single shaft, only 
the ball joint 26 with its drive finger 28 has been kept and only the 
shaft section 13 is mounted for rotation in its sleeve 15 equipped with 
the bearing 17, wheel 10 being supported directly by the bearings 23, 24 
of the reduction gear. The above described vehicle in its different 
embodiments is completed by a guide arm 33 at the rear of chassis 1 and a 
control system (not shown) incorporated at the end of this guide arm 33, 
for connecting the battery 7, through a potentiometer, to the motor 6. The 
chassis 1 is removably mounted on sleeves 14, 15 or only on sleeve 15 in 
the case of the embodiments shown in FIGS. 3 and 6, by means of a rapid 
release securing means. This securing means may for example consist of two 
notches 34 provided in the chassis 1 and engaging on the sleeve 14, 15. 
Because of the rigidity of this latter, the assembly formed by the chassis 
and the power unit also has good rigidity despite the obvious independence 
of the power unit. Finally, the vehicle includes a receptacle 35 for 
receiving the load to be transported and which is fixed by uprights 36, 37 
mounted respectively on the rod 2 and the guide arm 33.