The present invention refers to a propulsion unit for hand carts, particularly golf carts, of the type incorporating at least two spaced apart wheels, which are rotatably supported in a wheel undercarriage and between which wheels is provi¬ ded said propulsion unit incorporating at least one driving wheel, which can be driven by a power unit.

BACKGROUND OF THE INVENTION

Detachable propulsion units for golf carts are earlier known. An example of such an unit is shown by US-A-4 105 084, which has the features defined in the preamble of claim 1. These known propulsion units have a drawback in that they easily will slip and therefore are very inefficient.

It also has been suggested to preload the propulsion unit with a spring pressing the unit against the soil, but this means that the unit must be made integral with the hand cart, and that the propulsion unit can not be readily remo¬ ved, e.g. when the golf cart shall be used without propul¬ sion unit.

PURPOSE AND MOST ESSENTIAL FEATURES OF THE INVENTION

The purpose of the present invention is to provide a pro¬ pulsion unit of the type mentioned above, which is easily attachable to and detachable from the golf cart, which efficiently transfers substantially the entire golf cart weight to the driving wheel, which by a simple hand grip can be readjusted from a pulling to a pushing propulsion unit, which is easy to steer in spite of the propulsion unit, and which, when dismounted requires but small space. These tasks have been solved in that the driving wheel via a link is pivotably suspended in a support in the wheel undercarriage,

that the driving wheel is positioned behind the cart wheels as seen in -the- direction of travel, and that the axial length of the link and the radial extension of the driving wheel as measured from said support is bigger than the diptance from the support to the contact points of the cart wheels against the soil, thus that a torque is obtained when ^• the driving wheel is driven, which -torque gives the cart a lifting force.

DESCRIPTION OF THE DRAWINGS

The invention hereinafter will be further described with reference to the drawings, which show an embodiment thereof.

Fig. 1 shows in perspective the wheel undercarriage of the golf cart with mounted propulsion unit according to the invention.

Fig. 2 shows the golf cart according -to Fig. 1 in a side view wfth the propulsion unit in pulling position. Fig. 3 shows likewise a side view of the golf cart according to Fig. 1 with the propulsion unit in pushing position. Fig. 4 shows in-bigger scale a side view of a snap-in attachment for attachment of the propulsion unit to the wheel undercarriage. Fig. 5 shows a side view of an entire golf cart with pro¬ pulsion unit according to the invention and a separate joy¬ stick positioned at the handle of the cart.

DESCRIPTION OF EMBODIMENT

The golf cart shown in the drawing is of the type where the wheels and the wheel undercarriage are retractable into the golf bag, whereas the legs* of the wheel undercarriage in extended position are spread apart thus that the golf cart has a straddle-legged support against the soil. This golf cart is further described in EP-A-0 055 873, and therefore only the details which are associated with the propulsion

unit are described hereinafter. It however shall be pointed out that the propulsion unit according to the invention can be applied on most golf carts available on the market having a wheel undercarriage of the same or similar type as that shown in the drawing.

The golf cart shown incorporates thus a wheel undercarriage 11 consisting of an attachment plate 12 for supporting a golf bag 13. The wheel undercarriage 11 incorporates double tie rods 14 and 15, which each together form one leg, which articulatedly supports one cart wheel 16 each. A pair of slewing brackets 17, 18 are pivotably connected to the tie rods 14 and keep the legs of the wheel undercarriage in spread-apart position. A short distance below the slewing brackets 17 and 18 is provided a propulsion unit 20 between the wheels 16, which propulsion unit consists of a driving wheel 21, which by means of a link 22 is articulatedly connected to the tie rods 14 via bearings 23 and a yoke 24. This is supported with both its free ends in one clamping attachment 25 each, each of which clamping attachments with a simple hand grip can be clamped around the associated tie rod 14.

The link 22 of the propulsion unit 20 is shaped as a fork, the driving wheel 21 being journaled between the fork arms 26 and 27 thereof. In the upper part of the fork-shaped link 22 is provided a power unit 28 acting upon the propulsion unit and incorporating an electric motor 29, a chargeable accumulator 30 and an electronic unit 31, which via a cable 32 is connected to a control handle 33 at the handle 34 of the cart.

In one fork arm 26 of the link 22 is provided a transmission device 35, which in the embodiment shown is a gear belt transmission.

In order to give the golf cart a better steering ability,

the yoke 24 is axially displaceable in the supporting means 36 of the clamping attachments 25 and it is given a length bigger than the distance between the supporting means. The very clamping attachment 25 incorporates a clamping loop 37, which can be snapped over the tie rod 14, which has the shape of a tube 14 of rectangular cross section. The clam¬ ping l®op may be squeezed with a simple hand grip around the tie rod 14 by means of a clamping fitting 38. As earlier mentioned the supporting means 36 supporting the end por- tions of the yoke 24, is fitted to the clamping attachment 25, and in order to prevent the driving unit 25 during pro¬ pulsion of the golf cart from moving past the vertical plane through the centre of the cart wheels 16, at least on one end portion 39 of the yoke is fitted an axially displace- able, but non-rotatably supported stop member 40 shaped as a sleeve, to which is attached a tenon 41 allowing the propulsion unit 20 to pivot in a direction away from the soil, but preventing it from being pivoted to the opposite side of the cart wheels. In Fig.s 1, 2 and 6 the propulsion unit is positioned thus that a pulling force is obtained in the haiϊdle 34 of the golf cart. Sometimes it may be desi¬ rable that the golf cart is driven with a pushing force, and this can easily be effected with the propulsion unit 20 according to the invention in that this is turned around 180°, such as shown in Fig. 3. Sometimes it may also be desireable to disconnect the propulsion unit without this being removed from the cart and for this purpose a hook 42 is attached to the wheel undercarriage 11, which hook can be hooked into a ring 43 at the upper side of the propulsion unit, thus that the driving wheel 21 will be situated at some distance above the soil such as intimated with dash- dot-lines in Fig. 3.

The invention is not limited to the embodiment described and shown but a plurality of variants are possible within the scope of the appended claims.