Patent Description:
Manual rolling mills are used by jewellers and craftspeople in the manufacture of jewellery. Such manual jewellery rolling mills comprise a pair of parallel cylindrical rollers between which precious metals such as silver and gold are passed to reshape material. The rollers may have flat or textured/patterned profiles for sheet material and/or may include recessed grooves (for example having a half-round or v-shaped profiled) for processing wire. Some mills may have a combination of profiles on different portions of the rollers (for example a plain section and a grooved wire section). Some rolling mills may have interchangeable rollers with different profiles. The spacing between the rollers is typically adjustable to allow variation in the resulting thickness of the worked material.

At least one of the rollers is turned by the user during use via a crank handle. The crank handle is manually powered by hand-turning.

Example of manual rolling mills are shown in <CIT>, forming the basis for the preamble of claim <NUM>, and <CIT>. More complex and larger rolling mills which are powered by a power source such as an electric motor are shown, for example in <CIT> and <CIT>.

These forms of hand-powered rolling mills perform well and are widely used. However, it would be beneficial to provide an alternate or improved hand-powered rolling mill and embodiments of the invention seek to provide such a device which may, for example, have improved usability for the end user.

According to a first aspect of the invention there is provided a hand-powered jewellery rolling mill as claimed in claim <NUM>. The rolling mill comprises a support frame and a pair of opposed parallel cylindrical rollers rotatably mounted to the support frame. A drive shaft is connected to at least one of the rollers for rotation thereof. A manually rotatable handle is configured for providing a drive force to the drive shaft. The rolling mill further comprises an input shaft, rotatable by the manually rotatable handle. The input shaft has a worm. A worm-to-gear coupling transfers torque from the input shaft to the drive shaft.

The applicants have found that the use of a worm-to-gear coupling for transferring torque provides an advantageous arrangement over existing hand-powered jewellery rolling mill configurations.

The drive shaft is parallel to the axis of the cylindrical rollers. The drive shaft may, for example, be coaxial with one of the cylindrical rollers. A rotary coupling may be provided between the drive shaft and axle of the roller. The rotary coupling may for example be formed in opposed radial faces of the drive shaft and axle. For example, the coupling may be a tongue and groove coupling.

The input shaft is perpendicular to the drive shaft. The input shaft extends forward of the drive shaft relative to a feed direction of the rolling mill. The drive shaft axis may be parallel to the plane of the base of the support frame (for example it may be in a general horizontal alignment).

In contrast to existing arrangements, where a crank handle rotates about an axis parallel to the axis of the rollers, embodiments of the invention enable the handle to be repositioned. Thus, embodiments of the invention may provide an arrangement with improved ergonomics. Embodiments of the invention may also be more stable than existing arrangements as the action of rotating the handle will not create a moment that is inclined to tilt the rolling mill forward or backwards.

The input shaft may be offset below the axis of the pair of opposed generally parallel cylindrical rollers. This may further enhance the ergonomics by positioning the manually rotatable handle clear of the feed of the rollers and may increase the stability of the rolling mill in use.

The gear of the worm-to-gear coupling may be mounted on the drive shaft. As such the worm-to-gear coupling may be a direct coupling between the input shaft and the drive shaft. The worm-to-gear coupling provides a single stage reduction. Advantageously, the worm-to-gear coupling can provide a relatively high ratio reduction in a single stage. As such, in some embodiments the worm-to-gear coupling may have a reduction ratio of greater than <NUM> to <NUM>, for example greater than <NUM> to <NUM>. In some embodiments the reduction ratio of the worm-to-gear coupling may be between <NUM> to <NUM> and <NUM> to <NUM>, for example it may have a reduction ratio of <NUM> to <NUM>. Embodiments of the invention may provide a much greater mechanical advantage than a conventional manual rolling mill (which may for example have a <NUM> to <NUM> gearbox) whilst still providing a simple and reliable configuration.

The handle may be coupled directly to the input shaft.

The drive shaft may be coupled to one of the pair of opposed parallel cylindrical rollers. The rolling mill may further comprise a geared engagement between the pair of opposed parallel cylindrical rollers. For example, the manually rotatable handle may be provided proximal to a first axial end of the rollers and the rollers may be in geared engagement at the other axial end.

The rolling mill may further comprise an adjustor for setting the spacing between the rollers. The adjustor may include a control dial. The control dial may be provided at an upper portion of the support frame.

The drive shaft, the input shaft and the worm-to-gear coupling may be enclosed by a gearbox housing.

The gearbox housing may comprise a body adapted for attachment to the rolling mill. The body may for example have a base with a footprint that conforms to the external profile of one of the sides (for example an external side) of the rolling mill support frame. The gearbox housing may be removably connected to the support frame, for example by a number of through bolts. the gearbox housing may have an open box section which is closed by the side of the support frame.

The gearbox housing may comprise a drive shaft bore extending through the body in a first direction. The first direction may be perpendicular to the plane of the base of the gearbox housing. The gearbox housing may have an input shaft bore extending through the body in a second direction. The second direction may be perpendicular to the first direction. The second direction may be parallel to a sidewall of the gearbox housing. The bores may partially intersect to define a cavity for the worm-to-gear coupling.

The input shaft and drive shaft may be mounted on bearings within the gearbox housing.

The drive shaft bore may be a through bore. The gearbox housing may further comprise a cover closing the external end of the bore (which is the end of the bore distal from the frame of the rolling mill). The cover may retain the drive shaft and/or drive shaft bearings within the gearbox housing.

The input shaft bore may be a blind bore. The input shaft may extend beyond the open end of the bore to provide a stem. The manually rotatable handle may be attached to the stem. The gearbox housing may further comprise a flange surrounding the open end of the input shaft bore for receiving a bearing to support the input shaft. The input shaft may extend from a first bearing at the closed end of the input shaft bore to a second bearing proximal to the stem of the shaft. A retaining member may be connected to the housing at the open end of the input shaft bore to retain the input shaft and/or the input shaft bearing. The retaining member may have a central aperture for the stem to extend outwardly from the gearbox housing.

The gearbox housing, the drive shaft, the input shaft, the worm-to gear coupling, and the manually rotatable handle may be configured as a gearbox subassembly. As such the gearbox subassembly may be removably mounted on the frame of the rolling mill. For example, aligning and attaching the gearbox housing to the corresponding attachment points (for example bolt holes) on the rolling mill frame may position and bring into engagement the coupling between the drive shaft and roller.

The applicants have found that the use of a manually rotatable handle coupled through a gear train having a ratio of greater than <NUM> to <NUM> provides an advantageous configuration over existing designs. The rolling mill of embodiments may provide significant mechanical advantage in transferring torque to the rollers.

Whilst the invention has been described above, it extends to any inventive combination of the features set out above or in the following description or drawings within the scope of the invention as defined in the appended claims.

Unless otherwise stated, each of the integers described may be used in combination with any other integer as would be understood by the person skilled in the art.

Embodiments of the invention may be performed in various ways, and an embodiment thereof will now be described by way of example only, reference being made to the accompanying drawings, in which:.

In the context of embodiments of the invention references may be made to components being horizontal or vertical and it should be appreciated that such references are not intended to be limiting. Such terms are used for ease of reference and are intended to refer to the general directions relative to the apparatus when in use. For example, a "horizontal" direction or plane may, in practice, be defined by being generally parallel to the surface upon which the apparatus is mounted during use. Likewise, a "vertical" direction or plane may be defined by being generally perpendicular to the surface upon which the apparatus is mounted. As such, the relevant axis of the apparatus are not considered fixed in absolute terms (rather only relative to the underlying surface). Any other references to directions such as above/below or upward/downward are likewise intended to be interpreted in a relative, non-limiting, manner.

A hand-powered jewellery rolling mill <NUM> in accordance with an embodiment of the invention is shown in <FIG> and <FIG>. The mill <NUM> comprises a support frame <NUM>, a pair of opposed parallel cylindrical rollers <NUM>, <NUM> and a rotatable handle <NUM> for providing a drive force to the rollers <NUM>,<NUM>. The handle includes a wheel <NUM> and a crank member but other configurations may be possible. In use, a workpiece of precious metal <NUM> (shown for reference only in the figures and not part of the apparatus) is passed between the rollers <NUM>, <NUM> by actuating the rollers using the handle <NUM>. The metal is compressed to produce a desired thickness. An adjuster <NUM> is provided at the upper end of the rolling mill <NUM> for setting the spacing between the rollers <NUM>,<NUM>. The adjustor includes a control dial <NUM> and a gauge <NUM>. In use, a workpiece may be passed through the rolling mill several times with the spacing of the rollers <NUM>, <NUM> reduced progressively using the adjustor until the final thickness is achieved. The adjustor mechanism is not shown in the figures as it is enclosed by a protective guard, but suitable arrangements would be apparent to those skilled in the art (and the specific details are not essential to the present invention).

The frame <NUM> is formed from a single piece metal casting. As best seen in <FIG>, the frame <NUM> comprises two spaced apart parallel upright side members 4a, 4b which extend vertically from a horizontal base portion <NUM>. The base portion <NUM> is provided with bolt holes <NUM> at each corner to allow the rolling mill to be secured to a work bench during use. An upper joining member <NUM> connects the top of the side members 4a, 4b and is generally parallel to the base portion <NUM>. The frame defines a central aperture in which the rollers <NUM>, <NUM> are rotatably mounted.

The rollers <NUM>, <NUM> are generally cylindrical and formed of hardened steel. Each roller <NUM>, <NUM> is mounted on parallel axle extending perpendicular to the side members 4a, 4b of the side members. The feed direction of the rolling mill <NUM> is indicated by the arrow F on <FIG> and is perpendicular to the perpendicular to the axis of the rollers <NUM>, <NUM> and generally parallel to the base of the frame <NUM> (i.e. horizontal). The rollers <NUM>, <NUM> both include a first portion having a smooth cylindrical outside portion and a second portion having opposed grooves which define a shaped cross section gap (for example the grooves may each be V-shaped and jointly define a square section). The upper roller <NUM> is vertically adjustable relative to the lower roller <NUM> using the mechanism associated with the adjuster <NUM> such that the desired roller spacing can be set by a user. One side of the rollers <NUM> and <NUM> are engaged by a geared coupling <NUM> (covered by a protective cover in the figures) such that they rotate in unison. As will be known by those skilled in the art, the gears of the geared coupling <NUM> are configured with a tooth depth selected to ensure that they can intermesh sufficiently at a variety of spacings between the upper and lower roller. In the illustrated embodiment the geared coupling <NUM> is at an axial end of the rollers but it will be appreciated that in other embodiments the rollers could extend further beyond the coupling such that the coupling is in at a non-end section of the rollers/roller axles.

As seen in <FIG>, the lower roller <NUM> includes an axle stem <NUM> which extends beyond the frame <NUM> on the side member 4b opposite to the gear coupling <NUM>. The axle stem <NUM> includes a coupling feature <NUM> in the form of a radial tongue projecting axially from the end face of the axle stem <NUM>.

The rolling mill <NUM> is further provided with a gearbox subassembly <NUM> as shown in an exploded view with the mill in <FIG> and in isolation in <FIG> (assembled) and 4b(exploded). The gearbox subassembly <NUM> is assembled around a housing <NUM> which is a single piece metal casting. The housing <NUM> has a base portion <NUM> which is shaped and proportioned to conform to the external side of one of the side members 4b of the frame <NUM>. The housing <NUM> is removably attached to the side members 4b via bolts <NUM> which pass through holes <NUM> in the base portion <NUM> and into corresponding bolt holes <NUM> in the frame <NUM>. A bolt <NUM> is provided at each corner of the base portion <NUM>. The housing <NUM> encloses the axle stem <NUM> and when attached to the frame <NUM> aligns and engages a coupling member <NUM>, mounted within the housing (as will be explained further below), with the stem <NUM> such that the tongue <NUM> is received in a corresponding groove <NUM> of the coupling member.

The gearbox housing <NUM> defines a first bore <NUM> which extends transversely through the entire width of the housing. The interior (i.e. side closest to the frame <NUM>) end of the bore <NUM> surrounds the axle stem <NUM> and coupling <NUM> when the rolling mill <NUM> is fully assembled. The exterior end of the bore <NUM> is closed by a cap <NUM> attached by fasteners <NUM> distributed around the circumference of the cap <NUM>.

A second bore <NUM> is defined in the housing <NUM> and extends perpendicular to the first bore <NUM>. The second bore <NUM> is a blind bore having an opening at a forward end but not extending through the housing. The second bore <NUM> is positioned below the first bore <NUM>. The vertical spacing between the bores <NUM>, <NUM> is such that they overlap and partially intersect to define a common cavity <NUM> within the housing <NUM>. The second bore <NUM> extends generally parallel to the plane of the base <NUM> of the housing <NUM> (and therefore to the side 4b of the frame). The second bore is also generally parallel to the plane of the base portion <NUM> of the frame <NUM> (and as such is generally horizontally aligned). The second bore is closed by a cap <NUM> which includes an aperture at its centre (which as will be explained below is for the input shaft). The cap <NUM> is secured to a flange <NUM> formed in the housing <NUM> around the end of the second bore <NUM>. Fasteners <NUM> are provided to attach the cap <NUM> to the flange <NUM>, for example diametrically opposed pair of fasteners.

Within the housing <NUM> of the gearbox assembly is mounted a drive shaft assembly <NUM> and an input shaft assembly <NUM>. The drive shaft assembly <NUM> is connected to the lower roller <NUM> via the coupling <NUM> and axle stem <NUM>. The input shaft assembly <NUM> carries the rotatable handle <NUM> through which the user inputs torque to operate the rolling mill <NUM>. The detailed components of each assembly will be described further below with particular reference to <FIG>.

The drive shaft assembly <NUM> comprises a drive shaft <NUM> on which is mounted a gear <NUM>. The shaft is seated on a first and second bearings 64a, 64b provided on opposite sides of the gear <NUM>. The bearings <NUM> rotatably mount the shaft <NUM> within the bore <NUM> of the housing <NUM> where it is retained by the cap <NUM>. The inward end of the shaft <NUM> has a keyed profile to engage with the inner bore of the coupling <NUM> (which in turn engages the axle stem <NUM>).

The input shaft assembly <NUM> comprises an input shaft <NUM> on which is mounted a worm <NUM>. A pair of bearings 74a, 74b are provided at opposite sides of the worm <NUM> and rotatably mount the shaft <NUM> within the second bore <NUM> of the housing <NUM>. The first bearing 74a, at the external end of the shaft <NUM> is seated in the flange <NUM> of the housing <NUM> which surrounds the open end of the bore <NUM>. The second bearing 74b is located at the blind end of the bore <NUM>. A retaining split ring <NUM> is provided to axially fix the outer bearing 74a relative to the shaft <NUM>. The cover <NUM> retains the shaft in the housing <NUM>. A stem 71a at the outer end of the shaft <NUM> extends through the aperture of the cover <NUM>. The handle <NUM> is attached to the stem 71a. Thus, the handle <NUM> may be used to rotate the input shaft <NUM> and provide a motive torque to the rolling mill <NUM>.

As illustrated in the isolated view of <FIG>, the worm <NUM> of the input shaft <NUM> and the gear <NUM> of the drive shaft <NUM> form a worm-to-gear coupling <NUM>. It may be noted that the gear <NUM> has a dished profile to provide good meshing engagement with the worm <NUM>. The worm-to-gear coupling <NUM> is formed in the cavity <NUM> at the intersection of the first bore <NUM> and second bore <NUM> of the housing <NUM>. The worm-to-gear coupling <NUM> provides a relatively high gear ratio, for example a <NUM> to <NUM> ratio, in a simple single stage gear arrangement.

In use the operator rotates the manual input handle <NUM> as represented by Arrow A in <FIG>. This causes a rotation of the input shaft assembly <NUM> on its bearings. The rotation of the worm <NUM> in the worm-to-gear coupling <NUM> causes the gear <NUM> to rotate the drive shaft assembly <NUM> as represented by arrow B. The high ratio of the worm-to-gear coupling <NUM> allows the user to rotate the input handle <NUM> at relatively high speed and with relatively low force whilst transferring a required high torque to the drive shaft <NUM> and rollers <NUM> as represented by arrow C. As the rollers <NUM>, <NUM> are coupled by the gearing <NUM>, the upper roller <NUM> will rotate counter to the lower roller <NUM>, as shown by arrow D. The rotation of the rollers <NUM>, <NUM> acts to draw a workpiece through the gap therebetween when it is fed into the nip of the rollers by the user in the feed direction shown by arrow F.

An alternate hand-powered jewellery rolling mill <NUM>, not covered by the present invention, is shown in <FIG>. The mill <NUM> is of a similar basic construction to that of the first embodiment according to the invention and common features will not be described in further detail below. The mill <NUM> generally comprises a support frame <NUM>, a pair of opposed parallel cylindrical rollers <NUM>, <NUM> and a rotatable handle <NUM> for providing a drive force to the rollers <NUM>,<NUM>. The handle includes an arm <NUM> and a crank member <NUM> but other configurations may be possible.

The rolling mill <NUM> is further provided with a gearbox subassembly <NUM> best seen in the exploded views of <FIG> and <FIG>. Typically, the gearbox subassembly would include a protective housing attached to the side of the adjacent side member 204b but this is omitted in the figures for clarity. The housing could for example be a single piece metal casting.

The gearbox subassembly comprises a gear train <NUM> which mechanically couples the handle <NUM> to the rollers <NUM>, <NUM>. As will be explained further below the gear train <NUM> is designed to have a high gear ratio, for example greater than <NUM> to <NUM>, to provide significant mechanical advantage to the user when operating the rolling mill <NUM>.

The gear train <NUM> of the example includes multiple stages with an input gear <NUM>, first and second compound gears <NUM> and <NUM> and an output gear <NUM>. The input gear <NUM> is directly coupled to handle <NUM> such that it is rotated with the handle and is a small gear having <NUM> teeth. The compound gears <NUM> and <NUM> each include a large input gear 252a, 253a respectively having <NUM> and <NUM> teeth and a smaller output gear 252b, 253b each having <NUM> teeth. The output gear <NUM> is directly coupled to the upper roller <NUM> such that the roller rotates with the output gear and has <NUM> teeth. As noted above, the upper <NUM> and lower <NUM> rollers are connected via the coupling <NUM> such that when the upper roller <NUM> is rotated via the output gear <NUM> the lower roller will rotate at an equal speed and in the opposite direction (to cause the rollers to pinch together at their nip).

As can be appreciated from the figures, to provide a compact gear train <NUM> the gears are mounted coaxially about two parallel axis. The input gear <NUM> and second compound gear <NUM> are concentrically mounted on one axis and the output gear <NUM> and first compound gear <NUM> are concentrically mounted on the other axis. The two axis generally correspond to the axis of the rollers <NUM> and <NUM>. It may be appreciated that the output gear <NUM> and upper roller <NUM> are coaxial. As the axial spacing between the rollers may be adjustable the alignment between the lower roller <NUM> and the input gear <NUM> may either be configured to vary in use or the gear train may have sufficient tolerance to enable the axial spacing of the gears to vary. The axle <NUM> on which the input gear <NUM> and second compound gear <NUM> are mounted extends in cantilever manner outwardly from the side of the frame 204b of the rolling mill. The axle <NUM> includes a first portion <NUM> at the distal end for seating the input gear <NUM> and handle <NUM> and a second portion <NUM> at the proximal end for seating the compound gear <NUM>. The outer portions <NUM> has a reduced diameter in comparison to the inner portion <NUM> with a flange <NUM> being defined between the portions against which the input gear <NUM> can be seated.

In use, the user rotates the handle <NUM> and with it the input gear <NUM>. As will be noted the handle has a relatively long arm to provide mechanical advantage. The first reduction stage of the gear train <NUM> is provided between the input gear <NUM> (<NUM> teeth) the input 252a (<NUM> teeth) of the first compound gear <NUM>. The second reduction stage is provided between the output gear 252b (<NUM> teeth) of the first compound gear <NUM> and the input gear 253a (<NUM> teeth) of the second input gear <NUM>. The third (and final) reduction stage is provided between the output gear 253b (<NUM> teeth) of the second compound gear <NUM> and the output gear <NUM> (<NUM> teeth). Through these multiple stages the hear train can provide a total reduction ratio of <NUM> to <NUM>.

Embodiments of the invention may provide an increased mechanical advantage over conventional rolling mills without significantly increasing the complexity of the rolling mill or gearbox. Additionally, embodiments may provide a more stable configuration that may for example be useable even without bolting to a work surface. For example, the provision of a handle which requires less force at a higher speed has been found to improve the ease of use.

Further the handle position provided by the first embodiment of the invention may also be advantageous. With a conventional rolling mill the handle may be side mounted and may rotate about an axis parallel to the roller axis, the handle may include a relatively long crank arm to provide mechanical advantage. In combination these features may limit the location where the mill can be located or used. In contrast embodiments of the invention are able to use a smaller operating handle or wheel and mount the handle at the front of the mill. This may provide a convenient arrangement where, for example, the rolling mill of an embodiment can be placed at the edge of a work bench (with the handle extending forward and over the edge of the bench) providing a useful ergonomic arrangement for the operator to rotate the wheel and feed a workpiece whilst face on to the front of the rolling mill. Further, in embodiments of the invention the axis of the input handle and the rollers are in different orientations and this may provide a more stable arrangement which is less prone to tip the rolling mill forward or back during operation. The worm-to-gear coupling of embodiments also positions the axis of the input shaft and operating handle relatively low on the rolling mill which may further increase stability during use.

Although the invention has been described above with reference to a preferred embodiment, it will be appreciated that various changes or modification may be made without departing from the scope of the invention as defined in the appended claims. For example, whilst in the illustrated example the gearbox <NUM> and roller coupling <NUM> are on opposite sides of the rolling mill it will be appreciated that in some embodiments they could be arranged on a single side of the mill (for example to allow additional rollers to be provided on the opposite side external to the frame).

Claim 1:
A hand-powered jewellery rolling mill (<NUM>) comprising:
a support frame (<NUM>);
a pair of opposed parallel cylindrical rollers (<NUM>, <NUM>) rotatably mounted to the support frame (<NUM>);
a drive shaft (<NUM>) parallel to the axis of the cylindrical rollers (<NUM>, <NUM>) and connected to at least one of the rollers for rotation thereof; and
a manually rotatable handle (<NUM>) for providing a drive force to the drive shaft (<NUM>); characterised by further comprising
an input shaft (<NUM>), perpendicular to the drive shaft (<NUM>) and extending forward of the drive shaft relative to a feed direction of the rolling mill, the input shaft (<NUM>) rotatable by the manually rotatable handle (<NUM>), and the input shaft having a worm (<NUM>) and wherein a worm-to-gear coupling (<NUM>) transfers torque from the input shaft (<NUM>) to the drive shaft (<NUM>).