CA2227836A1 - Offset wheel chassis - Google Patents

Abstract

There is described an in-line skate chassis wherein the lateral position of one or more of the wheels can be offset relative to the chassis' longitudinal axis.

Description

OFFSET WHEEL CHASSIS

Present "in-line" skate chassis are called in-line because all the wheels are centered "in line" to the longitudinal axis of the chassis. My invention relates to a chassis that allows the user to variably offset their wheels relat1ve to the position of the longitudinal axis of the chassls .
Current in-line chassis keep the wheel ground engaging radius at the same angle and distance from the chassis on all four wheels. When a skater must turn, he must angle the chassis to begin the turning manoeuvre. This means that wheel #1 (starting from front to back) resists turning since it's scraping through the turning arc. In fact, wheels 1 and 2 resist turning since they are ground engaging throughout the manoeuvre.
My invention relates to a stepped configuration where any or all wheels can be offset relative to the skate's longitudinal axis to allow wheel 1 and/or 2 to raise above the ground or at least be relieved from most of the friction with the ground so that wheel #3 becomes the main pivot point in a turning manoeuvre. Currently, some chassis use a rockering technique that allows for vertical offset of the wheels relative to the chassis. This usually results in vertically offsetting #2 and #3 wheels to a slightly lower height relative to #1 and #4 wheels so that #2 and #3 wheels become the pivot point under the center of gravity (of the skater). The problem remains however that all four wheels still remain ground engaging so that the first and second wheels still resist the turning movement.
I have discovered that by laterally offsetting wheels #2 and #3 relative to the longitudinal axis of wheels #1 and #4, the ground engaging radius changes to actually raise and thereby relieve compression pressure from the first and second wheels so that there is less friction to interfere with the turning movement. In this particular offset arrangement, the skater does not have to offset the wheels vertically as well although both vertical and/or horizontal offset options can be maintained on the same chassis. Some skaters may wish to turn very aggressively where both offsets in combination could facilitate manoeuvres of this sort.
The present invention also takes into account the change in center of gravity between one skater and the next.
Since you want the center of gravity of the skater to remain centered above the third wheel, there is provided an offset spacer which can move the wheel more forwards or backwards to accommodate the center of gravity of each skater. Women have a more forward center of gravity so they will want to the move the #3 wheel more forward in relation to the skating direction.
The nos. 1, 2 and 4 wheels can also be provided with offset spacers for this type of forward or rearward adjustable displacement.
The wheel axles are designed to accommodate any variable offset the skater wishes to pursue. The skater simply loosens the axle which holds the wheel in place and moves the wheel along the axle to where the offset is desirable for him/her.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an upper perspective view of an in-line skate wheel chassis 10 including mounting plates 12 and 13 used to connect the chassis to the bottom of the skate boot (not shown), and a pair of parallel spaced-apart chassis rails 15 and 16 rigidly connected to plates 12 and 13. Rails 15 and 16 are formed with respective pairs of spaced apart axially aligned holes 20/21 elongated in the longitudinal direction of the rails. Axle supporting spacers 40 are connected into respective pairs of the holes 20 and 21 in the chassis rails as will be described below. Removing the spacers, rotating them 180~, and reconnecting them to the chassis will adjust the axle's positioning forwardly or backwardly which correspondingly moves the associated wheel to better accommodate the skater's center of gravity.

Figure 2 is a side elevational view of the chassis of Figure 1 showing ground engaging wheels 50 in phantom lines and the range of their forwards and backwards adjustability.
Figure 3 is a front elevational view of a conventional chassis with ground engaging wheels 50 aligned longitudinally with no lateral offset.
Figure 4 is a front elevational view of the chassis of Figure 3 in a turning attitude showing each of the longitudinally aligned wheels 50 in a ground engaging position.
Figure 5 is a front elevational view of the present chassis showing ground engaging wheels 1 and 4 (not visible) arranged in longitudinal alignment and wheels 2 and 3 laterally offset in the direction of the skater's instep. The offset of wheels 2 and :3 can be the same or, as shown, staggered. In all of the appended drawings, the offsets of wheels nos. 2 and 3 are shown greatly exaggerated for purposes of illustration. In use, the offsets may be mere fractions of a millimeter and may be up to or perhaps even in excess of 7 to 8 millimeters. In one embodiment tested by the applicant with good results, wheel #2 is offset by 4~ mm and wheel #3 is offset by 6 mm. Minimum offsets are more likely to be in the 1 to 2 mm range, as opposed to mere fractions of a millimeter.
Figure 6 is a front elevational view of the chassis of Figure 5 in a turning attitude with wheels 2 and 3 in a ground engaging position, and wheels 1 and 4 raised above the ground.
In the staggered offset configuration as shown in the Figure, wheel #3 bears most of the compressive load on the wheels and is therefore the main pivot point for the turn.
Figure 7 is a top plan view of a pair (left and right) of chassis in accordance with the present invention showing the offsets for wheels 2 and 3 relative to wheels 1 and 4. As will be appreciated, in a right hand turn, with only the left-hand skate in contact with the ground, wheels 2 and particularly 3 of the left-hand skate will be the main pivot point for the turn, with wheels 1 and 4 raised off the ground or at least relieved of some load. If the skater is pressing down at the toe or heel, then even in a turn some loading of wheels #l and/or #4 is possible. Wlth both the left and right-hand skates in contact wit:h the ground during the turn and with the skater's weight shifting from the right to the left skate, the right (or inside) skate merely turns into the turn and offset wheels 2 and 3 of the left skate again become the main pivot point for the turn.
Figure 8 is a perspective view of an axle supporting spacer 40 whi~_h comprises, in the example shown, a first plate 41 generally centered relative to a larger second plate 43.
Plate 41 fits into a respective hole 20 or 21 in either of rails 15/16 and is sized so that the plate snap or interference fits into place in each hole. Plate 43 is larger than holes 20/21 and forms a flange that bears against the inner wall of a respective rail 15/16 when the spacer is connected into place.
Each spacer includes an aperture 44 to receive a respective end of an axle 60 and is formed with a centering spacer 45 that can bear against the side 82 of a wheel's inner bearing race. The centering spacer, which preferably is made of a durable but low friction plastic or similar material, automatically centers or at least spots the lateral position of a non-offset wheel supported on the axle relative to the chassis. Aperture 44 is displaced towards one end of the spacer and is therefore positioned either forwardly or rearwardly relative to the chassis rails. Removing the spacer from the rail, flipping it 180~ and reconnecting it will result in a reversal of the aperture's relative positioning. The skater can therefore choose the appropriate spacer orientation depending upon whether the axle is to be located forwardly or rearwardly relative to holes 20/21.
Figure 9 is a perspective of a wheel supporting axle 60. In the example shown, the axle is generally tubular with a plurality of axially extending slots 62 formed into each of the axle's ends to extend partially along the axle's length towards its mid point. The slots allow the axle to expand upon insertion of threaded fasteners for frictionally connecting the ends of the axles into apertures 44, and the intermediate portions of the axle's outer surface to the inner surface 81 of the in-line skate wheel's bearing race 80 (see Figures 11, 12 and 13).
Figure 10 is an elevational, cross-sectional view of axle 60 and screws 68. Axle 60 is internally threaded at 69 on either side of its transverse center line 70 for connection to the threaded portions 67 of screws 68. The axle's inner surfaces 73 are tapered outwardly and the outer surfaces 75 of screws 68 are correspondingly tapered so that the insertion of each screw an~1 its progressive tightening into the axle causes the axle's diameter to expand. This expansion will fix the ends of the axles into apertures 44 of spacers 40 and will also securely locate the race 80 of the skate wheel at any point laterally along the length of the axle between rails 15 and 16.
Thus, wheels 1 and 4 will typically be located against centering spacer 45 to locate them along the same longitudinal axis and wheels 2 and 3 can be offset to the left (or right, depending upon the skate in question) by the desired amount. If desired, the axle's outer surface can be provided with spaced apart grooves, gaps, flats or detentes to incrementally locate the wheel's offset on the axle. The above-described means of connecting the axles to the chassis and of locating the wheels on the axles is intended to be exemplary only. Other means of accomplishing the same ends, such as the use of externally threaded axles, spacer clips, screw-type adjusters and so forth are also contemplated.
Figures 11, 12 and 13 schematically show the relative placements of wheels nos. 1 (and 4), 2 and 3, respectively, for the skate on a user's right foot. In these figures, only the wheel races 80, are shown, and not the wheels themselves. In Figure 11, wheel #1 is spotted with the side surface 82 of its race 80 bearing or nearly bearing against centering spacer 45.
Wheel #4 will be similarly positioned. As will be appreciated, wheels nos. 1 and 4 are not necessarily centered in relation to axles 60 or even chassis 10; it's merely appropriate that the two wheels share the same longitudinal axis. Spotting the wheels against or nearly against centering spacers 45 facilitates their correct alignment. In Figure 12, wheel #2 is offset to the left by the desired amount and in Figure 13, wheel #3 is shown offset even further to the left, again by the desired amount. In each instance, the progressive tightening of screws 68 into axles 60 will secure the axles to apertures 44 in spacers 40, and the wheels to the axles.
Figure 14 is again an upper perspective view of chassis 10. The above-described system of laterally offsetting the skate's wheels is adaptable to this and other shapes and types of in-line skate chassis. As shown, chassis rails 15 and 16 are corrugated along their length. The corrugations extend across the heights of the rails, but may extend in other directions.
The corrugations allow the use of thinner, lighter rails without a corresponding loss of strength. In fact, using corrugations may allow the rails to be thinned by as much as half or perhaps even more of their conventional thickness. For example, rails that would normally be 0.120" thick without corrugations may be 0.060" thick with corrugations.
Figure 15 is an upper perspective view of a chassis 100 modified for engineered strength and weight reduction. Rails 115 and 116 each comprise a lattice of struts 110 within a peripheral border or frame 114. Plates 12 and 13 are pared down to flanges 1]2 and 113. Cross members 115 interconnect the rails for torsional rigidity. The rails are preferably formed with axle-supporting spacers 125. As best seen from the plan view of Figure 16, the spacers are formed to quickly and automatically locate the wheels between the rails with predetermined offsets relative to the chassis' longitudinal axis. As wi]l be seen, the spacers will automatically align wheels 1 and 4 towards the left of the chassis as seen in Figure 16, wheel No. 2 will be located more to the right and wheel No.
3 will be offset a further increment to the right. As shown, wheel No. 3 in this setup will be located closest to the chassis' longitudinal center line. It is contemplated that in CA 02227836 l998-0l-23 some instances, there may be a slight offset of wheels 1 and 4 relative to one another.
The wheels themselves, while not shown, are rotatably mounted onto axles 160 inserted through aligned pairs of apertures 120 and 121 in spacers 125. Each axle is flanged 126 at one end to abut against the outer surface of the respective spacer 125 on rail 115 and is threaded 127 at its other end to engage reciprocal threads formed inside aperture 121 in opposite spacer 125. Flanges 126 can be peripherally facetted as shown 10 in Figure 17 to seat into corresponding shaped and sized recesses 129 in the outer surfaces of spacers 125 along rail 115. This prevents or at least inhibits unintentional loosening or backing off of the axles.
Using a relatively new technology called Thixotropic 15 Molded Magnesium, rails 115 and 116, including the spacers, plates and cross members, can be injection molded from granulated magnesium metal. This technique reduces the porosity encountered using more traditional die casting techniques and permits the construction of rails 115 and 116 having thicknesses 20 of as little as 30 thousandths of an inch (0.030") while still having the required strength and rigidity, although thicknesses of about 80 thousandths of an inch (0.080") will likely be more typical. The chassis is therefore both light and strong.
Forming axles 160 from magnesium produces further weight savings.
With reference to Figures 17 and 18, aesthetics of the chassis can be improved by connection of trims 176 and 177 which are typically molded from plastic. These trims include posts 179 to snap fit into apertures 174 formed in rails 115 and 116 at predetermined locations. When connected, the trims will cover some Ol~ all of the spacers and the ends of the wheel axles. The trims can be shaped to give the chassis the look of an ice skate undercarriage.
The use of magnesium has reduced the weight of chassis 100 to approximately 100 grams, which is significantly less than even the lightest competitive chassis now on the market. As well, the use of molded spacers and one-piece axles substantially reduces the number of parts required for assembly by the skater when changing wheels. This can be particularly important for competitive skaters who often change wheels in the course of a competition or contest and time is critical.
The above-described embodiments of the present invention are meant to be illustrative of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications, which would be readily apparent to one skilled in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set out in the follow:ing appended claims.

Claims (3)

1. An in-line skate chassis for supporting a plurality of ground engaging in-line skate wheels, wherein the lateral position of one or more of said wheels relative to the longitudinal axis of said chassis is adjustable.

2. The chassis of claim 1 wherein the longitudinal position of one or more of said wheels relative to the longitudinal axis of said chassis is adjustable.

3. The claims of claim 1 wherein the vertical position of one or more of said wheels relative to the horizontal longitudinal axis of said chassis is adjustable.