GB2477349A

GB2477349A - Hand-held weighing scales with reference scale on the rim of a display wheel and hence viewable from above

Info

Publication number: GB2477349A
Application number: GB201001633A
Authority: GB
Inventors: Victor Gregory Marshall
Original assignee: Baggage Scale Co Ltd
Current assignee: Baggage Scale Co Ltd
Priority date: 2010-02-02
Filing date: 2010-02-02
Publication date: 2011-08-03
Anticipated expiration: 2030-02-02
Also published as: AU2011200324A1; GB201001633D0; GB2477349B

Abstract

Hand-held mechanical weighing scales 10 comprise a tension rod (Fig. 2, 32) inside body section 4, connected to a load supporting hook 7. The tension rod is linearly movable between an unloaded and a loaded position and is biased in the unloaded position by a compression spring (Fig. 2, 30). A drive means (e.g. rack and pinion gears Fig. 2, 58, 52) connects the tension rod to a display wheel (Fig. 2, 38) in the handle 2, whose axis of rotation is perpendicular to the longitudinal axis of the tension rod. Movement of the tension rod under load causes rotation of the drive wheel and a reference scale on its circumferential outer surface thus indicates the weight supported by the hook. In use, the scale is viewable from above via display 20.

Description

WEIGHING MECHANISM FOR A HAND HELD SCALE

The present invention relates to a weighing mechanism, and in particular to a weighing mechanism for a hand held luggage scale.

Due to increasing pressure on air lines to decrease fuel consumption, resulting from increasing fuel costs and environmental considerations, the weight restrictions applied by airlines to passenger's luggage have become increasingly stringent. Passengers whose luggage exceeds a maximum weight limit are generally required to pay additional penalty charges proportional to the extra weight.

Therefore, there is a need for air travel passengers to be able to accurately measure the weight of their luggage and the contents thereof before travelling, to assess whether or not their luggage exceeds the maximum weight limit. It is also desirable to be able to transport the scales so that the weight of their luggage can also be checked prior to the return journey.

Hand held scales, such as mechanical spring balance scales, or digital scales, are known for use as luggage scales. Such scales typically comprise a handle, a scale body including the weighing means, and a hook for suspending the load to be weighed. Due to the manner in which hand held scale are used, it is important that the weight display is easily viewable by the user when holding the scale. Digital scales comprise a digital display which can be easily positioned on the scale in a conveniently viewable location, but are expensive to manufacture. Mechanical scales are cheaper to manufacture but typically comprise rotatable needle displays which are necessarily positioned on the side of the scales due to the arrangement of the weighing mechanism. As such, scales of this type are more difficult to view, and require the user to lift the load to their eye line in order to read the scale, which is awkward and particularly difficult for heavier loads. Other mechanical scales comprise overly complex weighing mechanisms, which undesirably increases both the cost and the weight of the scale.

It is therefore desirable to provide an improved weighing mechanism for a hand held scale, which address the above described problems, and/or which offers improvements generally.

According to the present invention, there is provided a weighing mechanism for a hand held weighing scale, as described in the accompanying claims. In addition there is provided a hand held weighing scale, as described in the accompanying claims.

In one aspect of the invention there is provided a weighing mechanism for a hand held weighing scale, comprising a load support member movable between a loaded and an unloaded configuration; a rotational scale display member having a circumferential outer surface and configured to be rotationally mounted within the body of a hand held weighing scale; drive means drivingly connecting the load support member and the scale display member, the drive means being configured to cause rotation of the display scale when the load support member moves between the loaded and unloaded configurations. The circumferential outer surface of the rotational scale member defines a display surface and comprises a reference scale provided thereon configured to indicated the load supported by the load support member as a function of the rotational displacement of the scale member.

Providing the reference scale on the outer circumferential surface of the rotational scale display member enables the reference scale to be viewed from above by a user when the rotational scale display member is mounted within the body of a hand held scale which is oriented substantially vertically in use. As such, only minimal lifting of the load is required, and a simple drive means may be provided to convert the linear motion of the torsion rod to rotational motion of the display wheel. In contrast, scales of the prior art utilise a linear-to-rotational drive means to rotate an indicator needle relative to a circular planar scale display having a reference scale provide on the face thereof. Such an arrangement must be provided on the side face of a hand held scale, as the drive means requires the display face to be oriented parallel to the longitudinal axis of the scale. As such, the reference scale cannot be viewed from above, and the scale must therefore be lifted to eye level to enable the display to be read by the user.

The load support member may comprise a longitudinal axis defined along the length thereof along which it is linearly movable between the loaded and unloaded configurations, and the rotational scale display member may comprise an axis of rotation arranged substantially perpendicular to the longitudinal axis of the tension rod. In use the longitudinal axis of the load support member is oriented substantially vertically. With the rotational axis of the rotational scale display member arranged perpendicular to the longitudinal axis of the load support member, the circumferential outer surface thereby comprises an upwardly facing portion in use allowing the refrence scale to be viewed from above.

The rotational display member may comprises a display wheel, which is preferably configured as a rotating drum.

The load support member may comprise a tension rod having a longitudinal axis defined along the length thereof and which is linearly movable along the longitudinal axis between the unloaded and a loaded configurations. The load support member further comprises a hook member connected to the distal end of the tension rod.

The weighing mechanism may further comprise a resilient member arranged to bias the load support member toward the unloaded position. As such, the reference scale is automatically rotated back to the zero position during unloading. The resilient member preferably comprises a compression spring.

The compression spring at least partially surrounds the load support member and the load support member is linearly movable relative thereto, thereby providing a compact mechanism which is easily housed within the scale body.

The load support member may comprise a flange section configured for engagement with the resilient member to enable the resilient member to bias the load support member to the unloaded position, and configured to compress the resilient member as the load support member is moved to the loaded position.

The drive means may be connected to the proximal end of the tension rod and to the display wheel.

The drive means may comprise a rack gear connected to the load support member and a pinion gear connected to the rotational display member. This arrangement enables the linear motion of the torsion rod to be converted to rotational movement of the display wheel with a minimal number of parts. The rack gear and the torsion rod may be integrally formed, thereby reducing part numbers and simplifying assembly.

The rotational scale display member may comprise a rotational axis with the circumferential outer surface of the display wheel being arranged parallel to the rotational axis, which provides the optimum viewing orientation as the scale is facing directly upwards in use. Alternatively, the outer circumferential surface may be angled towards or away from this perpendicular orientation providing the angle of the surface has at least a component which is upwardly facing or non-perpendicular to the rotational axis.

The rotational display scale comprises a plurality of apertures formed therein located radially'inwards of the circumferential outer surface. The apertures reduce the weight of the display wheel and the material used, thereby decreasing the weight and cost of the scale.

The weighing mechanism may further comprise a rotatable cover member having a viewing window..defined in at least a portion thereof and rotatable relative to the scale display member about a rotational axis. As the cover member is rotatable relative to the scale display member the viewing window may be rotated prior to use such that it is aligned with the zero indicator. In this way the scale can be easily zeroed before use, and any variation in the resting position of the zero can be easily corrected for by rotating the window, rather than requiring a complex zeroing mechanism.

The cover member may be positioned radially outwards of the circumferential outer surface of the scale display member and is rotatable relative to the scale display member to enable the viewing window to be selectively positioned along the reference scale provided on the outer circumferential surface.

The viewing window may comprise a magnifying lens configured to enlarge the view of the reference scale. This advantageously enables a smaller reference scale to be provided, thereby allowing a reduction in the size of the display wheel, while still enabling a clear view of the indicated weight by the user.

In another aspect of the invention there is provided a hand held weighing scale comprising a body comprising an upper surface which is upwardly facing in use, the upper surface including a window formed therein; and a weighing mechanism according to any preceding claim. The rotational scale display member is rotatably mounted within the body such that the outer circumferential surface is visible through the window. As the window is provided in the upper surface of the body, the reference scale is therefore visible form above in use.

The body preferably comprises a body section, and a handle section which includes the upper surface with the window formed therein. The window may comprise an aperture formed in the upper surface. Alternatively, the upper surface of the handle may be formed of a transparent material.

The load support member is preferably linearly movable relative to the body.

The cover member may be rotatably mounted to the body and positioned between the window of the body and the scale display member such that scale display member is viewable through the viewing window of the cover member.

At least a portion of the viewing window is formed from a transparent material, the transparent portiOn being selectively positionable along the reference scale of the display wheel to zero the scale before weighing. Alternatively the viewing window may be entirely formed from a transparent material and may include at least one reference marker for alignment with a selected point on the reference scale to zero the scale.

The load support member may comprise a base section which is slideably mounted to the body section, and a hook section which is rotatably mounted to the base section. This enables the hook section to be pivoted to a stowed position when not in use.

The base section may comprise a locating plate connected to the distal end of the torsion rod and configured to engage and compress the distal end of the compression spring.

Hence the spring is compressed in use between the flange section of the torsion rod and the locating plate, and the spring acts against the flange section and the locating plate to bias the torsion rod to the unloaded position.

The torsion rod is preferably clamped to the base section by the base plate. Specifically the locating plate may be comprise a two-part construction with define an aperture when combined which co-operates with a channel in the torsion rod to linearly locate and clamp the torsion rod.

The present invention will now be described by way of example only and with reference to the following illustrative figures in which: Figure 1 is a perspective view of a hand held scale according to an embodiment of the present invention with the hook in the open position; Figure 2 is a exploded view of the scale of Figure 1 showing the weighing mechanism in assembled form; and Figure 3 shows the torsion rod of the weighing mechanism of Figure 2.

Referring to Figure 1, a hand held weighing scale 10 comprises a handle section 2, a body section 4 and a load support section 6. The handle section 2 comprises an upper surface 3 and a lower surface 5 which is gripped by a user to hold the scale 10. The body section 4 extends downwardly from and substantially perpendicular to the handle 2 in a direction defining the longitudinal axis of the scale 10. The load support section 6 includes a hook portion 7, having a curved hook surface for receiving and supporting a load, and a base portion 9 to which the base of the hook portion 7 is pivotally connected. A display 20 is provided in the upper surface 3 of the handle 2, to provide a visual indication of the magnitude of the load supported by the scale 10.

As shown in Figure 2, the hook portion 7 comprises a pair of opposing side walls 12 and 14 which define a recess 16 therebetween. The hook portion 7 is pivotable about the base portion 9 between a stowed position, and an extended position as shown in Figure 1. The recess 16 is configured such that when the hook portion 7 is pivoted to the stowed position, a portion of the handle 2 is received within the recess 16 of the hook portion 7, to provide the scale 10 with a compact stowed configuration. In addition, in the stowed position the hook portion 7 defines a protective casing for the handle 2 to protect it from damage during transit. The scale 10 is also less susceptible to damage in the stored position as it is more compact, and therefore less prone to sheeting forces. The configuration of the hook portion 7 provides a hook which may not be considered as a metallic spike or barb, and is therefore suitable to be taken through airport security. In addition, the arrangement of the hook portion 7, using side walls 12 and 14 supported by an additional interconnecting side wall 18, provides sufficient strength for the hook to be manufactured from plastic, whereas the hook arrangements of the prior art are necessarily formed from metal.

Therefore, the hook of the present invention differs significantly from the hooks of the prior art. Specifically, the hook portion 7 is formed such that it does not present a security risk, and such that it functions as a protective housing for the handle section in the stowed position, and as such provides distinct advantages over the hooks of the prior art scales.

The handle portion 2 and body portion 4 are integrally moulded and formed having a two-piece construction, with each of the two-piece section being substantially hollow. The base portion 9 has a similar two-piece construction and is configured to surround the distal end of the body portion 4 such that it is linearly movable relative to the body portion 4 along the longitudinal axis of the scale. The hook portion 7 is formed as a single piece and is pivotally mounted to the base section 9.

The scale 10 comprises a weighing mechanism 30. The weighing mechanism 30 includes a torsion rod 32, a compression spring 34, drive means 36 and a display wheel 38. The display wheel 38 is rotatably mounted within the handle section 2, with the spindle 40 of the display wheel being received within integrally moulded bearing sections 42. The display wheel 38 comprises a drum configuration having a circumferential outer surface 44 which is provided at the radial periphery of the wheel 38 and extends about the circumference thereof. Alternatively, the display 38 may be formed as a segment, with the circumferential outer surface extending less than 360° about the rotational axis.

A reference scale is provided on the outer surface 44 comprising markings indicating the weight supported by the load support section 6. The markings (not shown) are configured to represent the weight supported by the load support section 6 as a function of the rotation of the display wheel 38, with a rotational displacement of x degrees corresponding to a supported load ofy grams.

The display wheel 38 further comprises a plurality of spokes 46 extending from the spindle 40 to the inner surface of the outer circumferential section of the display wheel 38.

Providing spokes 46 rather than a solid wheel body reduces the weight of the wheel 38 and the amount of material used, thereby minimising the weight and cost of the scale 10.

A pinion gear 52 is mounted coaxially on the spindle 40 and forms part of the drive means 30. The pinion gear 52 may be integrally formed with the display wheel 38 such as during molding. The torsion rod 32 extends longitudinally downwards from the display wheel 38.

The compression spring 30 also extends longitudinally beneath the display wheel 38 and radially surrounds the torsion rod 32, thereby providing a compact arrangement.

As shown in figure 3, the torsion rod 32 comprises a hollow shaft 50 including a plurality of spaced longitudinal columns 53 arranged about the circumference of the shaft 50, thereby reducing the weight and material volume of the column 50. A flange 54 is provided at the proximal end of the shaft 50, which is arranged perpendicular to the longitudinal axis of the torsion rod 32, and comprises at least a portion which extends radially outwards of the shaft 50. The flange 54 is configured to engage the proximal end of the compression spring 30 to compress the spring 30 in use. The distal end of the torsion rod 32 includes a channel 56 which receives a channel 56 which receives a corresponding recess 60 formed in the locating base plate 62 of the base section 9 to clamp the base section 9 to the torsion rod 32. A flange section 64 formed at the base of the body section 4 engages the distal end of the compression spring 30, such that in use the spring is compressed between the flange 54 of the torsion rod 32 and the flange 64 of the body section 2 as the torsion rod 32 is moved downwards.

A rack gear 53 extends from the proximal end of the torsion rod 32 and is longitudinally aligned therewith, such that the drive teeth of the rack gear 53 extend substantially perpendicular to the longitudinal axis of the torsion rod 32. The rack gear 53 is configured for engagement with the pinion gear 52 of the display wheel 38. The display wheel 38 and torsion rod 32 are mounted within the handle portion 2 and body portion 4 respectively such that the rack gear 53 engages with the pinion gear 52. The torsion rod 32 is slidingly received within the body portion 4.

When not in use, the compression spring 30, supported and located at its distal end by the flange section 64, acts against the flange 54 to bias the torsion rod 32 to an unloaded position, which represents zero load supported by the hook section 7. The display wheel 38 is arranged such that in the unloaded position the zero marking of the reference scale on its outer surface 38 faces upwards and is positioned at the upper most point of the outer surface 44, to represent zero load.

A viewing window 66 is positioned over the upper portion of the display wheel 38 between the display wheel 38 and the upper surface 3 of the handle portion 2. The viewing window 66 is positioned within an aperture 68 formed in the upper surface 3 and has a curvature corresponding to and radially offset from the curvature of the outer surface 44 of the display wheel 38. The viewing window 66 includes a side wall 70 which mounts the viewing window 66 to the bearing 42 such that the viewing window 66 is rotationally mounted to the handle portion 2 about a common rotational axis with the display wheel 38.

The viewing window 66 is preferably formed entirely of a transparent material, and includes reference markers 72 which are aligned with the reference scale of the display wheel 38 such that at any one time one of the weight indicators of the reference scale of the display wheel 38 positioned between the markers 72 which is taken to indicate the load supported by the scale 10. The portion of the viewing window between the markers 72 comprises a magnifying lens configured to enlarge the view of the reference scale.

Alternatively, the magnifying portion may be provided without the markers 72, with the boundary of eth magnifying portion defining the viewing reference section for alignment with the reference scale.

As the viewing window 66 is mounted to the bearing 42, and not the spindle 40, the viewing window is rotatable relative to the display wheel 38, but does not rotate with it in use. Rotation of the viewing window 66, and the reference markers 72, may therefore be used to zero the scale before use, by rotating the viewing window 66 such that the reference markers 72 align either side of the zero marker on the scale of the display wheel 38 before a weight is supported by the scale 10.

Once a load is supported on the hook section 7, the display wheel 38 rotates, with the weight indicator representative of the instantaneous load supported by the hook section 7 being positioned and viewable between the markers 72. Alternatively the viewing window 6 may be formed of an opaque material, with a viewing portion formed of a transparent material sized such that only a single weight indicated is viewable therethrough.

The drive means 36 of the display wheel 38 comprises the rack gear 58 and the pinion gear 52. When a load is applied to the hook section 7, the torsion rod 32 is pulled longitudinally downwards via its connection to the base section 9. As the torsion rod 32 is pulled downwardly the flange 54 compresses the compression spring 30 against the flange 64 of the body section 4. Downward movement of the torsion rod 32 against the biasing force of the compression spring 30, causes the rack gear 58 to move linearly and longitudinally downwards while in continued engagement with the pinion gear 52, thereby rotating the pinion gear 52 and hence the drive wheel 38.

The scale of the display wheel 38 is calibrated such that the force required to compress the compression spring 30 a given longitudinal distance is equated to given rotational distance of the display wheel 38, which is represented by the weight indicators on the reference scale of display wheel 38. As the reference scale of the display wheel 38 is provided on the outer surface 44, which is arranged perpendicular to the longitudinal axis of the scale 10, the scale is upwardly facing in use, and therefore visible through the upper surface 5 of the handle portion 2 through the viewing window 66. As such, when the handle portion 2 is gripped by the user about the grip portion 5, the indicated load of the reference scale positioned within the reference marker 72 is viewable for the user by looking downwards, without requiring the scale to be lifted upwardly to the user's eye level to view the side of the scale 10. As such, the load to be weighed by the scale 10 need only be lifted a minimal distance clear of the ground in order for its weight to be visually assessed by the user.

Claims

CLAIMS1. A weighing mechanism for a hand held weighing scale, comprising: a load support member movable between a loaded and an unloaded configuration; a rotational scale member having a circumferential outer surface and configured to be rotationally mounted within the body of a hand held weighing scale; drive means drivingly connecting the load support member and the display scale, the drive means being configured to cause rotation of the display scale when the load support member moves between the loaded and unloaded configurations; wherein the circumferential outer surface of the rotational scale member defines a display surface and comprises a reference scale provided thereon configured to indicated the load supported by the load support member as a function of the rotational displacement of the scale member.
2. The weighing mechanism of claim 1 wherein the load support member comprises a longitudinal axis defined along the length thereof along which it is linearly movable between the loaded and unloaded configurations and the rotational display member comprises an axis of rotation arranged substantially perpendicular to the longitudinal axis of the tension rod.
3. The weighing mechanism of claim 1 or 2 wherein the rotational display member comprises a display wheel.
4. The weighing mechanism of any preceding claim wherein the load support member comprises a tension rod having a longitudinal axis defined along the length thereof and which is linearly movable along the longitudinal axis between the unloaded and a loaded configurations.
5. The weighing mechanism of claim 4 wherein the load support member further comprises a hook member connected to the distal end of the tension rod.
6. The weighing mechanism of any preceding claim further comprising a resilient member arranged to bias the load support member toward the unloaded position.
7. The weighing mechanism of claim 6 wherein the resilient member comprises a compression spring.
8. The weighing mechanism of claim 7 wherein compression spring at least partially surrounds the load support member and the load support member is linearly movable relative thereto.
9. The weighing mechanism of any one of claims 6 to 8 wherein the load support member comprising a flange section configured for engagement with the resilient member to enable the resilient member to bias the load support member to the unloaded position, and configured to compress the resilient member as the load support member is moved to the loaded position.
10. The weighing mechanism of any preceding claim wherein the drive means is connected to the proximal end of the tension rod and to the display wheel.8. The weighing mechanism of any preceding claim wherein the drive means comprises a rack gear connected to the load support member and a pinion gear connected to the rotational display member.4. The weighing mechanism of claim 3 wherein the rack gear and the torsion rod are integrally fonned.5. The weighing mechanism of claim 3 or 4 wherein the display wheel and the pinion gear are integrally formed.9. The weighing mechanism of any preceding claim wherein the rotational scale display comprises a rotational axis and the circumferential outer surface of the display wheel is arranged parallel to the rotational axis.10. The weighing mechanism of any preceding claim wherein the rotational display scale comprises a plurality of apertures formed therein located radially inwards of the circumferential outer surface.
11. The weighing mechanism of any preceding claim further comprising a rotatable cover member having a viewing window defined in at least a portion thereof and rotatable relative to the scale display member about a rotational axis.
12. The weighing mechanism of claim 11 wherein the cover member is positioned radially outwards of the circumferential outer surface of the scale display member and is rotatable relative to the scale display member to enable the viewing window to be selectively positioned along the reference scale provided on the outer circumferential surface.
13. A hand held weighing scale comprising: a body comprising an upper surface which is upwardly facing in use, the upper surface including a window formed therein; and a weighing mechanism according to any preceding claim; wherein the rotational scale display member is rotatably mounted within the body such that the outer circumferential surface is visible through the window.
14. The hand held scale of claim 13 wherein the body comprises a body section, and a handle section which includes the upper surface with the window formed therein.
15. The hand held scale of claim 13 or 14 wherein the window comprises an aperture formed in the upper surface.15. The hand held scale of claim 13 or 14 wherein the load support member is linearly movable relative to the body.
16. The hand held weighing scale of any one of claims 13 to 15 when dependant on claims 11 or 12, wherein the cover member is rotatably mounted to the body and positioned between the window of the body and the scale display member such that scale display member is viewable through the viewing window of the cover member.
17. A weighing mechanism for a hand held weighing scale substantially as hereinbefore described with reference to, and/or as shown in any one or more of the drawings.
18. A hand held weighing scale substantially as hereinbefore described with reference to, and/or as shown in any one or more of the drawings.