AU748099B2 - Hand trolley for high mass loads - Google Patents

Description

WO 99/37521 PCT/AU99/00052 HAND TROLLEY FOR HIGH MASS LOADS INTRODUCTION TO INVENTION This invention relates to hand trolleys and in particular to an improved hand trolley adapted for handling and providing mobility for heavy loads.

BACKGROUND TO INVENTION Wheelbarrows, hand trolleys and a wide variety of manual wheeled manipulating manoeuvring and transporting devices find common use where short distance load movement is required.

The known prior art devices referred to above generally represent a compromise between load carrying capacity (weight and volume) and mechanical advantage and manoeuvrability. Each currently available device has its own combination of features which satisfy the above criteria to differing degrees.

Wheelbarrows are efficient at moving light loads over rough terrain and for tipping loads but do not have sufficient mechanical advantage for very heavy loads and must be loaded by hand.

Conventional hand trolleys provide more mechanical advantage than wheelbarrows but have difficulty traversing rough terrain and due to the size and positioning of their wheels, do not offer the optimum mechanical advantage for heavy loads.

In addition to the wheelbarrow and hand trolley, the prior art offers a wide range of dedicated lifting and manoeuvring devices. Various hand trolleys are provided for moving heavy loads of bricks and other regularly stackable items; such trolleys offer cages or locating means for securing a load or pallet of bricks or pavers. These types of hand trolleys also provide large wheels for traversing rough terrain and may also provide dedicated tines for locating a pallet. However, such trolleys still require the user to move the trolley from a vertical position to an out of vertical position prior to moving and this initial motion always requires the trolley to move the load through a substantial arc about the axis of the wheels thereby imposing a high burden on the operator with the center of mass of the load moving a considerable distance as the trolley is positioned for movement and potentially leaving the center of mass of the load PCT/AU99/00052 Received 15 February 2000 -2away from the axis of rotation of the wheels. Any load is most secure and easiest to move when its center of mass is close to or at the axis of rotation of the wheels of the trolley. Once the center of mass of the load moves away from the axis of rotation of the wheels or directly vertical above or below that axis, the load becomes increasingly more difficult to lift and stabilize.

In addition to the more generic devices, the prior art also includes a number of highly specific devices dedicated to handling specific loads.

Australian Patent No. 247111 discloses a trolley for lifting and carrying coils of wire. This trolley has dedicated lifting arms or tines for engaging an axled coil of wire. The configuration of the tines provides a ready means of scooping up a coil of wire and urging the coil to roll to a rearward position on the tines at or near the axis of rotation of the trolley wheels. Such a mechanical arrangement whilst encouraging the load to position itself with its center of mass near the wheel axis, still requires the load to move from a point far removed from the axis of rotation during the loading process.

Other prior art devices include elaborate loading systems or arms designed to gradually lift a load into the loaded position. However such devices are not generally applicable and must be used with dedicated pallets or loading equipment.

Therefore, none of the available prior art devices provide for easy lifting and short distance ready manipulation of generic high mass loads over rough terrain, for example, the lifting and transporting of paving bricks, sleepers, building bricks, rocks etc. over the rough terrain of a building or construction site.

OBJECT AND STATEMENT OF INVENTION One object of this invention is to provide an improved hand trolley.

Accordingly, in one aspect the invention provides, a trolley including a generally open frame for securely holding a loaded pallet at a first end thereof, a handle means for operating and manoeuvring said trolley at or near a second end thereof, wheels fitted to either side of said open frame characterized in that the axis of rotation of said open frame relative to said wheels is located substantially at AMENDED SHEE7

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PCT/AU99/00052 Received 15 February 2000 -3or near the center of mass of said loaded pallet when securely held in said open frame.

The frame may include two elongate spaced apart side members and a rear member defining a space into which said loaded pallet can be securely held.

In another aspect the invention provides a trolley including a generally open frame having wheels attached to either side thereof to allow said frame to move from a first substantially vertical position to a second inclined position allowing the free rolling of said trolley characterised in that said open frame includes two elongate spaced apart side members and a rear member defining a space into which a loaded pallet can be placed wherein said wheels are attached to said sides with their axis of rotation in a position corresponding substantially to the center of mass of said loaded pallet thereby reducing the turning effort required to move the trolley from said first to said second position.

The trolley may include two co-axially spaced apart wheels fitted to either side of the open frame such that the axis of rotation of the frame is about the axles of said wheels and corresponds with the axis of rotation of the wheels per se.

In an alternative embodiment the trolley may have two wheel sets fitted to either side of the frame with each wheel set being formed of two or three rotatable wheels fitted to a gusset which is independently pivotally fitted to the frame. The wheel sets therefore provide a separate axis of rotation for each wheel and another axis of rotation for the whole wheel set.

The wheel set may take the form of a triangular shaped gusset, most preferably equilaterally shaped and three wheels each placed at or near the apecies of the triangle.

The trolley may include one or a plurality of pallet engaging tines which are adapted to co-operate with a loaded pallet so as to engage said pallet and position said load as required to reduce the turning effort.

The trolley preferably includes two tines at or near the lower end of the side members. The tines preferably straddle either side of the pallet and allow the trolley to fully engage the pallet and position the load prior to moving said trolley.

The trolley may also include a cross brace spanning said side members at a height adapted to limit the load which can be placed on said trolley.

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WO 99/37521 PCT/AU99/00052 4 The rear of the trolley frame may also include one or a plurality of cross braces and optionally a solid back.

The invention will be described in greater detail with reference to the Figures as follows: Figure 1 shows a side view of the trolley about to be loaded.

Figure 2 shows a side view of the loaded trolley.

Figure 3 shows a front view of the unloaded trolley Figure 4 shows a plan view of the loaded trolley.

Figure 5 shows a side view of a multi-wheeled trolley.

DETAILED DESCRIPTION OF THE INVENTION Referring firstly to Figures 1 and 2, a particularly preferred embodiment of the improved hand trolley of the invention will be described where the hand trolley comprises a substantially open frame 1 being formed of two elongate side members 2 and two rear members 3 connected to the side members at the gusset regions 13 and 14. The side and rear members are held in a spaced apart relationship by braces 11 such that the open frame so formed defines a space 6 at a first end of the trolley. The two side members 2 terminate at a second end of the trolley in handles 8 which are adapted for gripping. Each side member has a wheel 4 fitted by way of a stub axle 5. In this embodiment, the trolley has two coaxially fitted wheels. The second end of the trolley has two pallet engaging tines 9 extending outwardly from the open frame. The pallet engaging tines are adapted to co-operate with a free standing pallet 10 onto which a load 7 has been placed. The wheels 4 are dimensioned and positioned via axle 5 such that the axle is positioned at a distance away from the first end of the trolley, specifically the lower terminal end of the side members 2, substantially equal to that of the distance from the side members to the rear member. When a pallet 10 fitted with a load 7 is engaged by the trolley, the load 7 can be substantially and securely housed within the confines of the open frame 1 such that the positioning of the axle 5 and the wheels 4, occurs substantially central to the mass of said load. The position of the load within the open frame in this manner and the positioning of the pivot or axis of rotation provided by the axle 5 around wheels 4, allows the ready rotation of the trolley and WO 99/37521 PCT/AU99/00052 the attached load 7 around the pivot provided by the axle 5, with a minimum change in the vertical moment of the mass and therefore minimal effort. The construction of the open frame, particularly having regard to the gusset region 14, is such that the movement of the trolley from a first vertical position where the pallet remains substantially in contact with the ground through to a second inclined position where the trolley has been rotated back, thereby lifting the pallet 10 off the ground and having the entire weight of the trolley and load supported on the wheels 10, is effected with a minimum of effort and with no interference with the rear of the pallet Referring now to Figure 3, a front view of the trolley clearly shows the open nature of the frame 1 and the positioning of the braces 11, so as to define the space 6 into which the load can be placed. The top brace 15 is preferably dimensioned to limit the height of a load placed on the trolley in order to avoid substantially exceeding the central moment of rotation of the mass. The pallet engaging tines 9 are clearly seen positioned at the lower terminal end of the two side members 2 in such a manner as to leave the open frame configuration of the trolley intact to allow the trolley to be moved forward and straddle a pallet during engagement such that the load can be made to move substantially into the final position on the trolley before the trolley is inclined and made to actually engage and move the pallet. In this manner, a heavy load can be engaged and brought to bear within the open frame of the trolley with minimal shifting of the load and with minimal rotational movement about the central moment of rotation as the trolley is moved from a vertical position into an inclined position.

Referring now to Figure 4, a plan view of the trolley details the open construction of the frame and serves to demonstrate clearly how the configuration of the trolley and the positioning of a load 7 can be made to fit within the confines of the open frame such that a substantial proportion of the load 7 and in particular the central axis of rotation of the load 7 can be made to align substantially with the axles Figure 5 provides details of an alternative embodiment of the trolley incorporating two wheel sets. Each wheel set includes a gusset 17 which is WO 99/37521 PCT/AU99/00052 6 freely rotatable about a pivot 18. The gusset is of equilateral triangular shape which is freely rotatable about a pivot 19 fitted at each apex. With this wheel arrangement, the trolley retains all the advantages of the two wheeled version except the frame rotates about the gusset pivot 18 rather than corresponding with the wheel axle. The smaller wheels 18 freely rotate independently while the rotatable gusset allows the trolley the option of more stabily negotiating uneven terrain. Of course, the smaller wheels may not suit all terrain and in another embodiment, the trolley can be provided with interchangeable large dual wheels and smaller wheel sets which can be selected according to the terrain embodiment.

In use, the trolley of the invention would be made available on a building site or other construction situation where pallet loads of pavers or other weighty construction components will have been placed around the building site and the trolley with large wheels 4 can be readily moved across the rough and/or uneven terrain of a construction site and brought in close proximity to the required pallet The trolley would then be raised to a substantially vertical orientation and moved forward to straddle the load 7 such that the pallet engaging tines 9 would engage the pallet 10. At that point in time, the back region 12 of the trolley would be substantially bearing upon the rear of the load 7 with the pallet fully engaged via the tines 9. The handles of the trolley can then be drawn back and pivoted around the axle 5 thereby effectively rotating the load 7 about its center of mass with minimal effort and once a suitable angle of inclination is reached that is comfortable for the operator, the trolley can be moved forwards, backwards, or readily manoeuvred around a building site, even over very rough or uneven terrain by virtue of the large wheels 4. When the trolley and its load have reached the required destination, the trolley is returned to a substantially vertical orientation and the weight is taken off the wheels 4 and the pallet 10 is positioned onto the ground by rotation around the axle 5. As soon as the pallet 10 makes contact with the ground, the trolley can be reversed out by removal of the pallet engaging tines 9 from the pallet 10 thereby leaving the pallet positioned with the load 7 freely available for use at the required position on a construction site.

WO 99/37521 PCT/AU99/00052 7 The trolley of the invention whilst sharing some features common to many hand trolleys, exhibits a particularly unique configuration of features that allow the ready and safe manipulation of very heavy loads. In particular, the trolley of the invention provides an extremely durable and versatile unit that can carry considerably greater loads than conventional trolleys or wheelbarrows. The trolley minimises the amount of material handling required at a building site and allows ready access for loading and unloading. The trolley also provides a ready means of loading railway sleepers, concrete pipes, bricks, blocks, pavers and a wide range of other materials. The particularly preferred details of the hand trolley features are not to be considered limiting in any way to the full scope of the invention.

Claims (11)

1. A trolley including a generally open frame for securely holding a loaded pallet at a first end thereof, a handle means for operating and manoeuvring said trolley at or near a second end thereof, wheels fitted to either side of said open frame characterized in that the axis of rotation of said open frame relative to said wheels is located substantially at or near the center of mass of said loaded pallet when securely held in said open frame.

2. A trolley according to claim 1 wherein said open frame includes two elongate spaced apart side members and a rear member defining a space into which a loaded pallet can be securely placed.

3. A trolley according to claim 2 wherein said wheels are attached to said side members.

4. A trolley according to any one of claims 1 to 3 having two co- axially spaced wheels either side of said frame wherein the axis of rotation of said open frame is about said wheels and corresponds with the axis of rotation of said wheels per se.

A trolley according to any one of claims 1 to 3 having two wheel sets fitted to either side of said open frame wherein each said wheel set includes two or more rotatable wheels mounted on gusset and said gusset is pivotally fitted to said open frame so as to provide an axis of rotation for said open frame relative to said wheels removed from the axis of rotation of said wheels.

6. A trolley according to claim 5 wherein said wheel set comprises a generally triangular shaped gusset having three wheels fitted at or near the respective appellees of said triangle and said gusset being pivotally fitted to said frame at a point equidistant from each wheel.

7. A trolley according to any one of claims 1 to 6 including one or a plurality of pallet engaging tines fitted to said first end which are adapted to co- operate with said loaded pallet so as to engage said pallet and securely position said loaded pallet in said frame. -AMENDED SHEET IPENAU WO 99/37521 PCT/AU99/00052 9

8. A trolley according to claim 7 having two tines adapted to straddle either side of said pallet and allow the trolley to fully engage the pallet and securely position the load prior to moving said trolley.

9. A trolley according to any one of claims 1 to 8 wherein said open frame includes a solid back and/or solid sides.

A trolley according to any one of claims 1 to 9 including a height limiting member to limit the size of said load so as to ensure the center of mass of said load remains substantially at or near the axis of rotation of the frame relative to said wheels.

11. A trolley according to any one of claims 1 to 10 substantially as hereinbefore described with particular reference to the example.