AU2084800A - Lift drive system - Google Patents

Description

P/00/01Il Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

S.

Invention Title: Applicant: LIFT DRIVE SYSTEM NOEL WILLIAM GEORGE RANKIN too.

best method of performing it known to me: W:thriswo-kC0MLETE2MAP-doc 2 LIFT DRIVE SYSTEM The invention relates to a lift drive system, and in particular to a system for selectively extending and retracting a support leg of a piece of equipment, such as a vehicle trailer or a dock leveller.

Trailer vehicles and similar are conventionally fitted with extendible support or landing legs which may be lowered to the ground in order to afford support of the trailer vehicle when uncoupled from its prime mover. Generally the lowering and raising of these legs is carried out manually by operating a crank applied to a leg rotary input shaft, but this operation is slow and arduous. A number of means have been devised in the past to power the lowering and raising operation, :i including the use of hydraulic power and air pressure operation.

15 Australian patent AU-B-48920/85 discloses a pressure air system for operation of a support leg, utilising a rotary air motor and an associated system of control valves, driven from the trailer air system. The device described is satisfactory in its operation but very costly to implement, rendering it not commercially viable in some circumstances. The reliance on an air line to drive the air motor adds an 20 undesirable level of complexity to the overall system.

According to the invention there is provided a system for selectively extending and retracting a support leg of a piece of equipment operated by actuating means including an input shaft rotatable about an axis of rotation, the system including a rigid bracket fixed relative to said support leg, and a rotary drive unit adapted for support by said bracket, the rotary drive unit having an electric motor and an output shaft driven by said electric motor, the bracket and the drive unit featuring mutually complementary engagement means affording removable engagement of the drive unit with the bracket, the drive unit being movable in a direction parallel to said axis of rotation to enable coupling of the drive unit output shaft with said actuating means input shaft, the mutually complementary engagement means preventing separation of the drive unit from the bracket while said shafts are coupled.

\41INNIECJBuisspedU jFT.DOC The invention, then, provides a simple and reliable system, quick to operate and more easily accommodated by vehicle trailers than existing arrangements. The electric motor drive can be used with one vehicle support leg, then uncoupled and removed from the actuating means of that support leg for use with the remaining support legs, before being stowed away on the vehicle body. For power, it requires only the presence of appropriately positioned electric power sockets in the vicinity of the respective support legs, coupled to the vehicle electrical power system.

Preferably, one of the drive unit and the bracket features one or more keyhole *orifices having elongate slot portions orientated parallel to said axis of rotation, the other of the drive unit and the bracket featuring one or more complementary flared studs, the one or more keyhole orifices and studs providing said mutually oo 15 complementary engagement means.

The keyhole orifices and complementary stud arrangement prevents movement between the drive unit and the bracket other than in the axial direction.

.0 20 Preferably the bracket has a channel form having a substantially horizontal planar base portion accommodating said drive unit.

In an alternative form, one of said drive unit and said bracket features at least one elongated tubular support member, and the other of said drive unit and said bracket features at least one elongated element engageable within said at least one elongated tubular support members, said at least one elongated tubular support member and said at least one elongated element being telescopically interengageable to provide said mutually complementary engagement means.

Preferably, in this form of the invention, two or more elongated tubular support members and complementary elongated elements are provided.

\\MINNIElCJBh\specilLIFT.DOC The drive unit may include a reduction gear and may be fitted with a handle for manipulation.

Preferably said two shafts are couplable by means of a removable drive pin, both shafts having a radial bore for receiving said drive pin.

The actuating means for operating the support leg preferably includes a gear selection unit, gear change being effected by movement of the input shaft in the axial direction. This provides an adjustable gear ratio for gearing for extending and retracting the legs.

In a preferred form, the drive unit has a portion in which a bore is provided, sized and positioned to receive and support said input shaft when the drive unit is engaged with the bracket.

In one version of the invention, the drive unit may provide an angled drive line between the electric motor and said output shaft. For example, the drive line may have a 900 turn.

In a further aspect, the invention provides a piece of equipment such as a vehicle semi-trailer having at least one support leg for selective extension and retraction in combination with the system described above.

The invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a side view of a conventional semi trailer vehicle; Figure 2 is a front view of a pair of landing legs of the conventional semi trailer; Figure 3 is a schematic perspective view of an electrical motor operated drive unit according to the invention, mounted to a landing leg; Figure 4 shows a support plate comprising a part of the lift drive system; Figure 5 is a schematic perspective view of a right-angle drive unit according to the invention; and kWINN1E%C8dUPchrsspdL[FT.DOC Figure 6 is a schematic perspective view of an alternative form of an electric motor operated drive unit according to the invention.

With reference to Figure 1, a semi trailer 10 is supported near its front end by a pair of conventional support legs 11. The semi trailer is connectable to its prime mover or to a further semi trailer by means of kingpin 12. Support legs 11 can be telescopically lowered and raised and, for this purpose, include an internal screw mechanism actuated by a rotary input shaft 13. This is conventionally operated by hand by means of a crank handle which engages the input shaft 13 and is manually rotated to extend or retract support legs 11.

As Figure 2 shows, both support legs of a pair are operated jointly by an intermediate rotary shaft 20, which drives the internal screw mechanism of the legs through bevel gears (not shown). A two speed gearbox 21 is shown, being 15 an optional component of the drive system, allowing a selection between a high gear and a low gear effected by axial translation of input shaft 13. Low gear is generally used for lifting a loaded trailer, whilst high gear is used for more rapid raising or lowering of the legs when the trailer is unloaded.

0 20 The drive unit of the invention for powering the operation of rotary input shaft 13 is illustrated in Figure 3. In this instance the drawing does not show the twospeed gearbox 21 external to the support leg, but it is understood that such a °oeoo component may be included and will not affect the realisation of the invention.

A support bracket indicated generally at 30 and extending from support leg 11 is fixedly attached relative to the leg by means of mounting bolts 31 engaging with a chassis part 10 OA of the semi trailer. Support bracket 30 is of rolled steel formed into a channel shape having a planar base portion 32, two side wall portions 33 normal to base portion 32, and two lateral longitudinal flange portions 34 parallel to base portion 32. This profile affords a high bending stiffness to support bracket base portion 32 providing a horizontal planar support surface. Mounting bolts 31 fix one end of wall portions 33 and flange portion 34 against chassis part as illustrated, the end of base portion 32 abutting the external wall of support leg \MINNIECJB\Cdrt sspeCLFT.DOC 6 11. Support bracket 30 may therefore readily be retro-fitted to conventional trailer support legs simply by machining appropriate threaded bores to receive bolts 31.

The drive unit indicated generally at 40 includes a dc electric motor 41, a planetary reduction gear 42, and a mounting plate 43. These components are provided as an integral unit, for example as subcomponents fixedly interconnected by welding, which unit is removably engagable with input shaft 13 in a very simple and reliable manner, as will be described in more detail below.

Mounting plate 43 is of rectangular planar form sized to fit against planar base portion 32, within the channel formed by support bracket 30, and has an integral orthogonal tongue-form flange 44 as shown, which in use is orientated vertically, S:I parallel to the face of leg 11. Flange 44 features a circular bore 45 therethrough, positioned to be concentric with the axis of shaft 13 when in position and sized to ••el 0 15 accommodate the shaft. Electric motor 41 and reduction gear 42 are mounted by means of bolts or otherwise to mounting plate 43 such that the output shaft 46 from reduction gear 42 is concentric with bore Oil.

Support bracket base portion 32 is provided with three keyhole orifices 35, the 20 elongate keyhole slot portions 36 directed towards support leg 11 as shown in Figure 4, whilst the base plate 43 of drive unit 40 has three complementary 0.00 downwardly projecting flared (eg flat-headed or mushroom-headed) studs 48, two 0 of which are illustrated for clarity in dotted line in Figure 3, sized to pass into the keyhole orifices 35 and to engage by sliding with keyhole slot portions 36.

In use drive unit 40 is introduced into the channel formed by support bracket and flared studs 48 engaged into keyhole orifices 35. Drive unit 40 is then slid longitudinally in the direction of keyhole slot portions 36 such that bore 45 slides over input shaft 13 and drive output shaft 46 engages with input shaft 13. The two shafts both feature radial bores in cooperating male and female end portions, such that they can be locked together by insertion of a removable drive pin 47.

Electric motor 41 is then coupled by means of a quick connection plug (not shown) to a source of direct current, such as a battery carried on semi trailer \MI1NNIEBchrdmspedULIFT.DOC or to a socket connected to the vehicle electric power system, and the drive unit can then be selectively operated to lower/raise legs 11. The keyhole slot portions 36 of keyhole orifices 35 permit the longitudinal movement needed to change between low gear and high gear as drive unit 40, together with input shaft 13 to which it is now coupled, is pushed in or out relative to leg 11. The mutually complementary engagement means provided by drive unit 40 and support bracket 30 prevents relative movement between (and hence separation of) the drive unit from the bracket in a direction perpendicular to the axis of input shaft 13 while said shafts 13 and 46 are coupled.

When operation is complete, pin 47 is removed and drive unit 40 can then be slid into a position from which it may be easily removed by lifting away from support

.:I

i plate 30 and stowed if required (for example, under semi trailer 10) or employed on a further set of support legs. A handle 49 may be provided integral with 15 mounting plate 43 to assist in manoeuvring drive unit 40. In the case of a modern double trailer, commonly known as a Double, a common drive unit can be used, a support bracket 30 and a power source being fitted to each trailer. If required, support bracket 30 may be foldable in such a way that it can be folded into a stowed position when not in use to reduce the overall width of semi trailer 10, and folded out for introduction of the removable drive unit when the support legs are to be operated.

The system of the invention is illustrated in the form of a straight drive line to input shaft 13. In certain situations in which only very limited space is available a rightangle drive can be used, again adapted to be slidably movable in the axial direction of input shaft 13. Referring to Figure 5, the components of the system for use with a right angle drive unit are identified with similar reference numerals to those of Figure 3, with the addition of 100 to each reference numeral. The support bracket 130 is a modified version of that described above (referenced at 30) and in place of a channel form features a horizontal planar form with an additional back plate 50 and a stiffening gusset 51 as shown, provided to each side of the support leg 11.

\\IINNIE\CJBO. SpeduLIFT.DOC 8 Drive unit 140 features a drive line having a 900 angle therein, although other angular variations are to be contemplated. This is accomplished by an additional gearbox 52 driven from the output of reduction gear 142 and turning the drive through a right angle, by means of appropriate gearing such as meshing bevel gears or a worm gear. An output shaft 146 from gear box 52 couples in a similar manner to that previously described, by means of a radial drive pin, to the input shaft 13 of leg 11. Drive unit mounting plate 143 is fitted with two handles 148a and 148b and cooperates with support bracket base portion 132 by means of a complementary set of flared studs and keyhole slots. Once again, drive unit 140 is readily removable to allow it to be utilised with different trailers. Drive unit 140 is symmetrical about a vertical plane through the axis of rotation of motor 141 and features an output shaft on both sides of gearbox 52, this symmetric arrangement allowing for left-or right-hand application depending on the geometry of the positioning of support leg 11.

lol* S Turning to the alternative form of the invention depicted in Figure 6, it is to be noted that the components of this system are identified with similar reference numerals to those used in Figure 3, with the addition of 200 to each reference numeral. The support bracket and means of providing mutually complementary 20 engagement between the drive unit and the input shaft 13 differ somewhat from the embodiments described above, as will be explained in further detail below, while not departing from the scope of the invention.

Drive unit 240, which may be housed in an optional cover box 250 for safety and case of handling, is similar in design to the inline drive unit 40 of Figure 3.

However, base plate 243 need not be perforated. Instead, two elongated cylindrical steel pins 248 are welded to drive unit 240 on either side of base plate 243, positioned parallel to the axis of output shaft 246 as shown. Support leg 11 is provided with two elongated tubular steel members 235 fixed, by bolting or otherwise, to leg 11 to project outwardly therefrom in a direction parallel to the axis of input shaft 13. The spacing and position of tubular members 235 is such that the free ends of pins 248 can be inserted into the open ends of the bores of tubular members 235 and telescopically slid therethrough, bringing shafts 13 and \WMINNIECJBdSSPeCnLIFT.DOC 246 into engagement. Tubular members 235 therefore provide a simple form of support bracket 230 fixed to leg 11, and tubular members 235 and/or pins 248 may be provided with additional locking means (not shown) to retain their engagement once shafts 13, 246 have been themselves engaged.

Tubular member 235 may be removably attachable to a steel web 53 integral with support leg 11, by means of threaded bosses 237 and complementary nuts (not shown), such that, once tubular members 235 are removed and stowed, the outer profile of leg 11 is undisturbed. This form of the invention finds particular application on vehicle trailers with a very limited available mounting area.

Whilst the invention has been illustrated and described in the context of the landing legs of a vehicle semi trailer, it will be appreciated that it may be applied to other support legs. Furthermore, many modifications to the construction 15 described may be envisaged, and it is understood that any such modifications and/or additions to the embodiment specifically described and illustrated herein may be made without departing from the spirit or scope of the invention.

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Claims (8)

1. A system for selectively extending and retracting a support leg of a piece of equipment operated by actuating means, the actuating means including an input shaft rotatable about an axis of rotation, the system including a rigid bracket fixed relative to said support leg, and a rotary drive unit adapted for support by said bracket, the rotary drive unit having an electric motor and an output shaft driven by said electric motor, the bracket and the drive unit featuring mutually complementary engagement means affording removable engagement of the drive unit with the bracket, the drive unit being movable in a direction parallel to said axis of rotation to enable coupling of the drive unit output shaft with said actuating means input shaft, the mutually complementary engagement means preventing separation of the drive unit o from the bracket while said shafts are coupled. o o

2. A system according to Claim 1, wherein one of the drive unit and the bracket features one or more keyhole orifices having elongate slot portions orientated parallel to said axis of rotation, the other of the drive unit and the *bracket featuring one or more complementary flared studs, the one or 20 more keyhole orifices and studs providing said mutually complementary engagement means.

3. A system according to Claim 1 or Claim 2, wherein the bracket has a channel form having a substantially horizontal planar base portion said drive unit being accommodated within said channel form.

4. A system according to claim 1, wherein one of said drive unit and said bracket features at least one elongated tubular support member, and the other of said drive unit and said bracket features at least one elongated element engageable within said at least one elongated tubular support members, said at least one elongated tubular support member and said at least one elongated element being telescopically interengageable to provide said mutually complementary engagement means. \%MINNIEBCJBdvftXsp eCPI IFT.DC 11 A system according to any preceding claim, wherein drive unit includes a reduction gear.

6. A system according to any preceding claim, wherein said input shaft and said output shaft are couplable by means of a removable drive pin, both shafts having a radial bore for receiving said drive pin.

7. A system according to any preceding claim, the actuating means for operating the support leg including a gear selection unit, wherein gear change is effected by movement of the input shaft in the axial direction. S.8. A system according to any preceding claim, wherein the drive unit has a portion in which a bore is provided, sized and positioned to receive and support said input shaft when the drive unit is engaged with the bracket. s e

9. A system according to any preceding claim, wherein the drive unit provides an angled drive line between the electric motor and said output shaft. S~10. A system according to claim 9, wherein said drive line has an 20 approximately 900 drive line turn.

11. A piece of equipment, such as a vehicle semi-trailer, having at least one support leg for selective extension and retraction, in combination with the system of any proceeding claim. DATED: 10 March 2000 PHILLIPS ORMONDE FITZPATRICK Attorneys for: NOEL WILLIAM GEORGE RANKIN 19(9 P16 V 4'v W:ch rtsped.IFT.DOC