Technical Field

The present invention relates to devices that aid in determining the volume of an object and more particularly but not exclusively to aid in determining the minimum volume of a cube that will contain the object.

Background of the Invention

Postal authorities such as Australia Post, frequently base their charging on the density of the parcel. As a particular example Australia Post base their charging on whether the density is greater than 250 kg per cubic metre. Accordingly there is a demand to calculate the density of the object being transported. However that density is calculated relative to a minimum volume of a cube within which the article can be contained. That is, a "virtual cube" that would contain the article.

Methods and devices have been proposed which will provide the volume of the abovementioned "virtual cube". These methods and devices have failed to meet the demands in respect of standards (accuracy), ease of use and suitability for the work environment.

For example, previous methods have included determining the weight of the article by means of scales and then measuring the various dimensions of the parcel via a tape. A computer is then employed to calculate the "virtual cube" and therefore the density. This method is not only inaccurate but is also time consuming.

Attempts have been made to address the above problems. These attempts have included scanning the article (as an example via laser) and then attempting to calculate the volume of the "virtual cube". These scanning methods have proven to be inaccurate.

A still further disadvantage is the cost of manufacture of these scanners.

Object of the Invention

It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages. Summary of the Invention

There is disclosed herein a device to aid in calculating the volume of a rectangular prism to contain an article, with the article resting on a base, the device including, a support to be positioned adjacent the base, an arm movably mounted on the support, the arm having a portion to be moved into engagement with the article to aid in determining the minimum volume of a rectangular prism that would enclose the article, said portion being movable in X, Y and Z directions relative to said support, and sensors to detect displacement of said portion to provide a horizontal longitudinal length, a horizontal transverse width and a vertical height of the prism

Preferably, said device includes transmitters operatively associated with the sensors to provide signals indicative of the length, width and height for delivery to a computer s Preferably, said arm is mounted on said support so that said portion is movable linearly in said directions

In an alternative preferred form, said portion is movable angularly about a honzontal X and a horizontal Y axis and is movable upwardly so as to have a vertical direction component of movement 0 Preferably, said portion is a sphere

Preferably, the sphere is located on a lower extremity of said arm

Preferably, said rectangular prism is a cube

Preferably, said arm is telescopic with at least two telescopic longitudinal sections S In an alternative preferred form, said arm is an elongated flexible element

Preferably, said arm is upwardly retractable when released

Brief Description of the Drawings

A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings wherein o Figure 1 is a schematic front elevation of a device to aid in determining the volume of a rectangular prism, Figure 2 is a schematic elevation of the device of Figure 1 ; Figure 3 is a schematic side elevation of the device of Figure 2; Figure 4 is a schematic top plan view of the device of Figure 4; Figure 5 is a schematic side elevation of a modification of the device of Figures 1 to 4;

Figure 6 is a schematic front elevation of a modification of the device of Figures 1 to 4;

Figure 7 is a schematic end elevation of the device of Figure 6; and Figure 8 is a schematic top plan view of the device of Figures 6 and 7.

Detailed Description of the Preferred Embodiments

In the accompanying drawings there is schematically depicted a device 10 to aid in determining the minimum volume of a rectangular prism within which an article can be located. For example the device 10 may be employed by a postal authority to aid in determining the minimum volume of the previously mentioned "virtual cube". In this respect it should be appreciated that a rectangular prism encompasses cubes.

The device 10 is intended to be mounted adjacent a generally horizontal surface (base) 11 upon which an article 12 rests. For example the surface 11 may be part of the front counter of a postal authority. The surface 1 1 would need a grid that would provide for the accurate location of the article 12 in a predetermined position enabling it to be engaged by the device 10, thereby enabling the device 10 to accurately calculate volume.

In this embodiment the article 12 is as cube, however it should be appreciated that the article 12 may be of other configurations and that the device 10 is intended to provide the minimum volume of a cube that would encompass the article 12.

The device 10 further has a frame 13 that includes an upper generally horizontal beam 14. The beam 14 supports a telescopic member 15. The telescopic member 15 includes an upper part 16, an intermediate part 17 and a lower part 18. However it should be appreciated that the member 15 may have two, three of four telescopic parts. Typically the parts 16, 17 and 18 are telescopically associated with adjacent parts 16, 17 and 18 being supported by linear bearings 19. The part 18 adjacent its lower end is provided with a handle 20 that is gripped by a user to aid in moving the lower extremity of the part 18. The part 18 at its lower most extremity is provided with a sphere 21 that is used to contact the article 12.

Attached to the upper extremity of the part 18 is an elongated flexible element (wire) 22 that is wound about a spool 23 urged to retract the element 22 onto the spool 23.

5 For example the spool 23 may be operatively associated with a spring that causes rotation of the spool 23 about the axis 24 to wind the element 22 onto the spool 23. Operatively associated with the spool 23 is a rotary encoder (and transmitter) 25 that provides a signal indicative of the angular displacement of the spool 23 about the axis 24. Accordingly the encoder 25 provides a single signal indicative of the displacement of the sphere 21 along the longitudinal axis 26 of the member 15.

Preferably, the telescopic member 15 has the part 18 urged to retract into the part 17, and the parts 17 and 18 urged to retract into part 16.

The member 15 is supported for angular movement about a first axis 27 that is generally horizontal and parallel to the beam 14. The member is also supported fors angular movement about a second axis 28 that is also horizontal and generally perpendicular to the axis 27.

The member 15 is mounted on the beam 14 by means of a two axis gimbal 29 that acts as a "universal joint".

Located internally of the gimbal 29 are two angular encoders (transmitters) 30o that provide signals indicative of the angular displacement of the member 15 about the axes 27 and 28.

The encoders 25 and 30 deliver signals to a microprocessor 40 that communicates with a computer 41. Operatively associated with the microprocessor 40 and computer 41 is a touch screen 42 that a user operates to control the device 10. 5 The computer 41 upon receiving information from the microprocessor 40 and touch screen 42 can calculate the displacement of the ball 21 in the X, Y and Z directions and therefore determine the volume of the cube that would encompass the article 12. That is the ball 21 would be moved to the various extremities of the article 12. Once at each extremity the operator via means of switch 43 would activate the encoders 25 and 30Q to send signals to the microprocessor 40. In the above described preferred embodiment the sphere 21 is employed to aid in more accurately determining the point of contact with the article 12. The sphere 21 will always engage the article 12 at a radial point from the centre of the sphere 21.

The above described preferred embodiment may be modified by providing a counter balance for the member 15.

In a further preferred embodiment, the member 15 may be mounted on the beam 14 for linear movement in the X and Y directions, with the member 15 secured so that the axis 26 is always generally vertical. As a further modification there may be linear movement in the X or Y direction and pivoting the other direction. In Figure 5 there is schematically depicted a modification of the device 10. In this embodiment there is provided a device 50. To replace the member 15 there is provided an elongated flexible element 51. The element 51 may be metal wire or other elongated flexible element that is relatively inelastic. The element 51 is wound about the spool 23, with the spool 23 urged to retract the element 51 so that the element 51 is under tension. Again the spool 23 would be mounted on the gimbal 29.

In the above described preferred embodiments, the volume of the virtual cube that would encompass the article 12 can be accurately determined. A further advantage is that the device 10 is easy to operate and easily mounted adjacent a work bench such as a counter of a postal authority. When not in use, the member 15 is telescopically retracted so as to not obstruct the work surface.

In Figures 6 to 8, there is schematically depicted a modification of the device 10. In this embodiment the device 60 has carriage 62 that is linearly moveable in the direction 61 on the beam 14. The member 15 is angularly movable about the horizontal axis 63, the axis 63 being generally parallel to the direction 61. Movement of the member 15 in the direction 61 is measured by an encoder 65.

The encoder 65 and its associated reel 64 is mounted on the carriage 62 so as to move therewith. An elongated flexible element 66 is attached to a remote end of the beam 14. The reel 64 is urged to retract the element 66. The encoder provides a signal as previously described to indicate the displacement of the carriage 62 and therefore the member 15. A switch 67 provides an indication of the "home" position.