GB2167360A - Hand truck - Google Patents

Abstract

A hand truck is disclosed for transporting furniture and general goods over short distances, and particularly up and down stairs. The hand truck includes a pair of main wheels (16) at one end and a pair of handles (13) at the other end. A ball bearing undercarriage (12) defines a line passing close to the lower perimeter of the main wheels (16). The undercarriage (12) is spring loaded, so as to be normally in a position towards the handle end of the hand truck. The undercarriage (12) can slide longitudinally relative to the hand truck towards the main wheel end, while supporting the weight of the hand truck and its cargo. In this manner, the weight of the hand truck can be taken on the undercarriage (12) as the hand truck is drawn upstairs. As the main wheels (16) go over each step, and move to a position on the horizontal portion of the step, the weight of the truck can be moved onto the main wheels (16), allowing the spring- loaded undercarriage (12) to return to the handle end of the truck ready for travel up the next step. <IMAGE>

Description

SPECIFICATION Hand truck This invention relates to a hand truck of the type used for moving household goods such as furniture and other items of similar weight.

Hand trucks are particularly useful, especially in flat areas where wheeled vehicles are easily managed. Some difficulty is, however, always encountered when these vehicles are used in ascending or descending stairways. Some of the prior art hand trucks developed especially for stairways include triple-axled trucks, wellknown in the art and to the public, and motor powered, tractive belt drive trucks. Motorpowered trucks are heavy and expensive, as well as often being much slower to move on flat ground than are the manual trucks. Tripleaxled trucks, although superior to single-axled trucks of the prior art in stair climbing, still require considerable effort in ascending stairs.

Triple-axled trucks, when descending stairs, can also get away from the operator and create dangerous situations.

Related to the above described hand trucks are generally manual haulage devices such as wheelbarrows and trolleys, and these type of devices are defined herein as being within the scope of the term "hand truck".

The aim of the invention is to provide a hand truck which will ameliorate disadvantages of the prior art.

The present invention provides a hand truck for transporting goods over short distances, the hand truck comprising a support frame extending in a longitudinal direction, a handle on one longitudinal end of the frame, and wheel means at the opposite end of the frame, wherein a sliding support is attached to the frame so as to be slidable in said longitudinal direction relative to the frame, the sliding support including a ground-engaging surface positioned in a plane which passes through the wheel means.

Preferably, the wheel means is constituted by a pair of spaced apart coaxial wheels, and the sliding support is a frame including two longitudinal runners defining the ground-engaging surface, each runner extending from a point between the axis and perimeter of a respective one of the pairs of wheels.

It is further preferred that the sliding support runs on bearing means located between the frame and the support, with bias means, such as a spring, urging the support towards the handle end of the truck.

The wheels may be of the known triple axle type.

An additional pair of spaced apart coaxial wheels is preferably included at the handle end of the truck, with a portion of the periphery of said wheels being on the lower side of the ground-engaging surface.

A hand truck constructed in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the hand truck; Figure 2 is a side elevation, with one wheel removed for clarity, of the hand truck, of Fig.

1; Figure 3 is a schematic representation showing the truck in use ascending a flight of stairs; and Figure 4 shows the bearing arrangement used in the hand truck of Figs. 1 and 2.

Referring to the drawings, Figs. 1 and 2 show a hand truck including a main frame structure 10 having generally longitudinally-extending side members with transverse members therebetween. A sliding support 11 is slidably attached to the frame 10, a rotary bearing means 14 being located cooperatively between the frame and the sliding support.

The sliding support 11 can also be in the form of two generally longitudinally-extending sections 11 with their own transverse members therebetween. The frame 10 has handles 13 at one end, along with auxiliary wheels 17, and rear main wheels 16 at the other end.

The sliding support 11 is attached to the frame 10 with a predetermined amount of free play so that, when the weight of the truck (and any load which it is carrying) is taken by the sliding support, the weight is transferred to the frame via the bearings 14. When no load is being carried by the sliding support 11, there is sufficient free play between the sliding support and the bearings 14 so that it drops a small amount of clearance from the bearings 14. In this situation, a spring 18 biases the support 11 in the direction towards the handle 13 end of the hand truck.

The support 11 includes a ground-engaging surface 12, which is covered with leather or a similar material. The ground-engaging surface 12 is positioned in a plane which intersects the region of the rear main wheels 16 between their axes of rotation and the load bearing portions of their perimeters.

The bearing means 14 must be kept approximately evenly spaced along each sliding support 11, so as to ensure its smooth longitudinal movements. This can be done by using conventional bearing cages, or by placing the bearing elements 14 in a number of galleries defined by ridges 21 formed on the surface of one of the bearing races, as shown in Fig. 4.

The handles 13 are rotatable about the general longitudinal direction of the truck. This rotary action of the handles 13 allows a high point to be grasped during stair ascension (see Fig. 3), and allows a low point to be grasped (see Fig. 2) when the truck is being used on level ground, and is required to be tilted somewhat so as to obtain the counterbalancing effect, which takes the majority of load off the operator. The handles 13 may include a releasable lock-type devices, such as spring-loaded balls and dimples, so as to ensure there is no unwanted movement of the handles. Positive engagement of the handles 13 within the frame 10 can be provided, for example by screw attachment.

A luggage support 15 is provided at the main wheels 16 end of the truck.

The main advantage of this truck is enjoyed while ascending, and to a lesser degree while descending, stairways. Fig. 3 shows the general ascending operation.

The truck is brought up to a flight of stairs 20, as shown in the lower portion of Fig. 3, until the support 11 is brought up to the outer line of the steps 20. At this point, the truck is pulled upwards with the support 11 remaining stationary relative to the steps 20, and the truck moving with little effort, the load being supported by the bearings 14 against the support 11, until the main wheels 16 come to engage the edge of the next step 20. This position is shwon in the upper portion of Fig.

3. The main wheels 16 end of the truck then lifts slightly as the wheels go up over the edge of the step 20. The truck is then pulled so that the wheels 16 are again in a position illustrated in the lower portion of Fig. 3 securely above the edge of the step 20. At around this point in the operation, the handle 13 end of the truck can be lifted slightly, so that the support 11 no longer engages with the steps 20, and the spring 18 will return the support 11 to its initial position relative to the frame 10 of the truck. Thus, the truck is again ready to encounter another step 20.

In this device, the maximum angle at which the operator has to pull is the angle of inclination of the steps 20. With for example, a conventional triple-axled truck, the average angle of pull will be the angle of the steps encountered. However, at the initial portion of the pull for any one step, the angle required (and therefore the effort required) is greater than the average amount. Thus, the truck of the present invention, by virtue of the sliding support 11, allows the same weight object to be taken up a flight of stairs, with a lower necessary maximum pull at any one time.

Moreoever, because of the rotary handles 13, the truck is more easily manipulated in varying conditions.

In descending steps, the truck is generally allowed to move on the wheels 16, except where a wheel 16 is bellow the edge of one step, but has not reached the horizontal portion of the next step therebelow. In this position, the truck is gradually eased down, by sliding on the level surface 12. In this form, the support 11 is up against a stopping means (not shown) which prevents any travel in the direction towards the handles 13. An alternative form might include the use of a very stiff spring attached similarly to the spring 18, but acting in the opposite direction, so as to urge the support 11 towards the main wheels 16 end of the truck whenever the support travels towards the handle end 13 beyond its natural position.

A further improvement of the device is the addition of wheel brakes. Any convenient wheel brake may be used, and is best applied by either one of two brake levers fitted to the handles 13 of the hand truck. In operation, the wheel brakes are applied while descending stairs. With the brakes applied, the main wheels 16 stop the progress of the hand truck each time the main wheels come to the edge of a step 20. By gently releasing the brakes, the hand truck is eased over the edge of the step. The brakes can also be used, while ascending steps, by keeping the truck steady at the balance point, where the weight is on the wheels 16 and the ball bearing undercarriage is returning by the spring action.

Claims (11)

1. A hand truck for transporting goods over short distances, the hand truck comprising a support frame extending in a longitudinal direction, a handle on one longitudinal end of the frame, and wheel means at the opposite end of the frame, wherein a sliding support is attached to the frame so as to be slidable in said longitudinal direction relative to the frame, the sliding support including a ground-engaging surface positioned in a plane which passes through the wheel means.

2. A hand truck as claimed in claim 1, wherein the sliding support runs on bearing means located between the frame and the sliding support, bias means being provided for urging the sliding support towards the handle end of the truck.

3. A hand truck as claimed in claim 2, wherein the bias means is a spring.

4. A hand truck as claimed in any one of claims 1 to 3, wherein the wheel means is constituted by a pair of coaxial wheels.

5. A hand truck as claimed in claim 4, wherein the ground-engaging surface of the sliding support lies in a plane intersecting the wheels between the portions of their perimeters which are furthest from the support frame and their rotational axes.

6. A hand truck as claimed in claim 2, or in any one of claims 3 to 5 when appendant to claim 2, wherein the sliding support comprises two laterally-spaced, longitudinally-extending members of U-shaped cross-section, the bearing being located within said U-shaped members.

7. A hand truck as claimed in claim 6, wherein the bearing means include ball or roller bearings maintained in spaced apart relationship by a bearing cage.

8. A hand truck as claimed in claim 6 or claim 7, wherein each U-shaped member comprises a plurality of longitudinally-spaced galleries defined by transverse ridges extending across said members.

9. A hand truck as claimed in any one of claims 1 to 8, wherein the handle comprises two handle portions, each handle portion being attached to a respective transverse side of the frame, and being rotatable relative to the frame about the longitudinal axis thereof, each handle portion further including manually-graspable sections subscribing generally transverse circles upon the rotation of the handle portions.

10. A hand truck as claimed in claim 9, wherein each handle includes a positive locking mechanism for locking said handle portions in predetermined, selectable orientations.

11. A hand truck substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.