Patent Publication Number: US-6039329-A

Title: Roller skate shock absorber system

Description:
RELATED APPLICATION 
     This application is a Continuation-in-Part application of U.S. patent Ser. No. 08/584,187 filed Jan. 11, 1996, now U.S. Pat. No. 5,823,543. 
    
    
     FIELD OF INVENTION 
     This invention relates to a roller skate shock absorber system, and more particularly to such a system which provides for both a stiff push off force and also resilient shock absorption. 
     BACKGROUND OF INVENTION 
     As roller skating with both double wheel and in-line skates has become more popular as an exercise, as a fun sport and even for commuting, the need for a more versatile suspension system has grown and intensified. The growth of the in-line skate market has accelerated this need. In-line skates enable and encourage faster and more challenging skating. In many areas, it is difficult to find a smooth skatable route which is long enough to satisfy an enthusiastic skater. Thus, skaters tend to endure rough roads and even to go off-road trail blazing to find the desired distance and challenge. Whether on rough roads or trail blazing, the rough bumpy terrain can be punishing to the skater&#39;s muscles and joints, and dangerous too. While attempts have been made to soften the bumps, especially in in-line skates, using softer wheels, springs and the like, no suitable solution has been provided. This problem presents a dilemma. If the suspension is soft or springy enough to absorb shocks, then it tends to be too soft or sloppy in the push-off mode and if the suspension is stiff enough to enable efficient transfer of push-off force, then shock absorption is poor. In many cases, the resilience in the suspension is provided by simple springs which do not truly absorb the shocks encountered on rough routes. A serious shortcoming of present skates is that they do not absorb well shocks from all directions--front, angled, and vertical, all of which can be encountered on rough and bumpy roads. 
     SUMMARY OF INVENTION 
     It is therefore an object of this invention to provide an improved roller skate shock absorber system which is both stiff for push-off and resilient for shock absorption. 
     It is a further object of this invention to provide such a roller skate shock absorber system which is inexpensive and simple to manufacture and use. 
     It is a further object of this invention to provide such a roller skate shock absorber system which does not require special skate shoes or wheels. 
     It is a further object of this invention to provide such a roller skate shock absorber system which performs well on bumpy, loose and soft surfaces. 
     It is a further object of this invention to provide such a roller skate shock absorber system which absorbs front, angular and vertical impacts. 
     It is a further object of this invention to provide such a roller skate shock absorber system which is easy to adjust. 
     This invention results from the realization that a shock absorber system in the form of a four bar linkage biased into position by a shock absorber allows for a firm push-off force at the front of the skate and yet at the same time provides improved overall shock absorption and that a single adjustment mechanism can be used to adjust the stiffness of the shock absorber. 
     This invention features a suspension system for a skate including a shoe and a truck. Such skates include in-line skates, roller skates, cross-country ski training devices and the like. There is a four bar linkage including a forward mount connectable to the shoe, a rearward mount connectable to the shoe, a first double pivoting mechanism interconnecting the forward mount with the truck device, and a second double pivoting mechanism interconnecting the reward mount with the truck device. There are also means for biasing the truck device with respect to the shoe. 
     The first double pivot mechanism typically includes a member pivotably attached on one end to the forward mount and pivotably attached on the other end to the truck device. The second double pivot mechanism typically includes a member pivotably attached on one end to the rearward mount and pivotably attached on the other end to the truck device. 
     The means for biasing preferably includes a shock absorber subsystem pivotably attached on one end to the truck device and pivotably attached on the other end to the shoe. The shock absorption system may be attached to the shoe via the rearward mount. The shock absorber subsystem comprises a first shaft pivotably attached to the truck device, a second shaft pivotably attached to the shoe, and a resilient member disposed to bias the position of the first shaft relative to the position of the second shaft. The resilient member is usually disposed about the first shaft. The second shaft includes an orifice for slidably receiving the first shaft. The second shaft also includes an adjustment mechanism for adjusting the position of the first shaft relative to the second shaft. This adjustment mechanism may include a housing and bolt receivable in the housing. The housing is pivotably connected to the shoe via the rearward mount. The bolt includes a head engaged with the resilient member for simultaneously adjusting the resiliency of the resilient member and the position of the truck device with respect to the skate shoe. 
     The means for biasing may include a shock absorber subsystem pivotably attached on one end to the truck device and pivotably attached on the other end to the shoe, the shock absorber system including a resilient member and means for adjusting the resiliency of the resilient member. The means for adjusting comprises a first shaft pivotably attached to the truck device and a second shaft pivotably attached to the shoe, the resilient member disposed to bias the position of the first shaft relative to the position of the second shaft. 
     The first double pivoting mechanism includes first pivot means proximate the forward mount and second pivot means proximate the truck device, the first and second pivot means disposed generally one on top of the other and generally vertically aligned to provide decreased vertical resiliency for the forward push-off portion of the skate. There may be means for adjusting the vertical alignment of first and second pivot means between 0 and 25°. The second double pivot mechanism includes third pivot means proximate the rearward mount and fourth pivot means proximate the truck device. The third and fourth pivot means are disposed generally not one on top of the other and not generally vertically aligned to provide increased vertical resiliency for the rearward shock absorbing portion of the skate. The vertical alignment of the third and fourth pivot means is normally between 30° and 50°. 
     There is also a brake device removably attached to the truck device. Finally, there are means for releasably locking the position of the shock absorber subsystem. The front and rear mounts may be separate or portions of a single rigid plate. 
    
    
     DISCLOSURE OF PREFERRED EMBODIMENT 
     Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which: 
     FIG. 1 is a side elevational diagrammatic view of the suspension system of this invention; 
     FIG. 2 is a schematic diagram of the suspension system of this invention; and 
     FIG. 3 is side elevational diagrammatic view of another embodiment of the suspension system of this invention showing in cross-section the shock absorber subsystem of this invention; 
     FIG. 4 is a schematic view of another embodiment of the shock absorber subsystem of this invention; and 
     FIG. 5 is a schematic view of the removable brake shoe in accordance with the subject invention. 
    
    
     The suspension system of this invention includes a four bar linkage made up of a typical skate shoe 12 and skate truck 14, first, forward double pivoting member 16 extending between skate shoe 12 and truck device 14, and second, rearward double pivoting member 18 also extending between skate shoe 12 and truck device 14. First double pivoting member 16 includes first pivot means in the form of shaft 20 and second pivot means in the form of shaft 22. Second double pivoting member 18 includes third and fourth pivot means in the form of shafts 24 and 26, respectively. Shaft 20 pivotably interconnects member 16 with forward shoe mount 62 and shaft 22 pivotably interconnects member 16 with truck 14 between sidewalls 64 and 66 separated by a plurality of in-line wheels 68, 70, 72, and 74 each on axles spanning between sidewalls 64 and 66. Shaft 24 pivotably interconnects rear member 18 with rear shoe mount 78 and shaft 26 pivotably interconnects member 18 with truck device 14. The suspension system of this invention also includes some means for biasing the four-bar linkage and truck device 14 into one or more positions with respect to skate shoe 12 such as shock absorber subsystem 28 extending between pivot point 24 on skate shoe 12 and pivot point 30 on truck device 14. As shown in phantom at 28&#39; and 28&#34;, FIG. 2, however, shock absorber subsystem 28 may interconnect shoe 12 and truck device 14 (shock absorber subsystem 28&#39;) or, alternatively, interconnect pivot point 30 and member 18 (shock absorber subsystem 28&#34;), or may extend between any two links, any two pivot points, or a pivot point and a link. Thus, the shock absorber subsystem, depending on where it is placed, can be used to modify the height of the skate shoe and/or to change the appearance of the skate. 
     In the preferred embodiment, first and second pivot means 20 and 22 are disposed generally one on top of the other and generally vertically aligned as shown to provide decreased vertical resiliency for the forward portion of the skate shoe thus allowing for a firm push-off by the wearer of the skate. Because of this vertical or near vertical alignment, (i.e. somewhere between 0 and 25°), the resiliency in the direction of vertical vector 40 is decreased and yet four bar linkage 10 in combination with shock absorber subsystem 28 provides adequate resiliency in all other directions schematically shown by vector 42 to absorb shocks which occur because of uneven surfaces. Also in the preferred embodiment, pivot points 24 and 26 of rearward member 18 are not generally vertically aligned one on top of the other, (i.e. somewhere between 30-50°), thus providing increased vertical resiliency in the rearward portion of the skate as shown by vector 44 while at the same time providing adequate shock absorbing characteristics in all other directions schematically shown by vector 46. 
     Shock absorber subsystem 28 biases truck device 14 into the position shown in FIGS. 1 and 2 with respect to skate shoe 12. Shock absorber subsystem 28, FIG. 3 includes shafts 120 and 126. Shaft 120 includes lower shock absorber mount 124 pivotably secured to truck 14 via shaft 90. Lower shock absorber mount 124 includes socket 122. Shaft 126 includes housing 127 pivotably attached to rear mount 78 via shaft 24 and hollow bolt 130 threadably received in housing 127. Hollow bolt 130 includes adjustment head 127 and shaft 120 is slidably received within hollow bolt 130. Resilient member 92, FIG. 1, resides on shaft 120, FIG. 3 and extends between socket 122 of lower shock absorber mount 124 and head 127 of hollow bolt 130. Resilient member 92 is conveniently replaced or exchanged with another resilient member of different resilience, color, shape, length, or material simply by disconnecting upper pivot 20 from plate 140 and allowing shaft 120 to slide out of bolt 130. Head 128 is engaged with resilient member 92 as shown in FIG. 1 for adjusting the resiliency of resilient member 92 by varying the position of shaft 120, FIG. 3 within hollow bolt 130 and housing 126 in the direction of arrow 129. 
     Plate 140 secures the relative location of upper pivots 20 and 24 independent of the skate shoe and provides additional stiffness for the entire skate in the case where skate shoe 12 has a relatively flexible sole portion. Also shown in FIG. 3 is single rigid plate 140 with front 142 and rear 144 mount portions. 
     In the preferred embodiment, there is only the single shock absorber for minimizing the number of components of the suspension system thus lowering the manufacturing cost. Set screw 150 is used to adjust the vertical alignment of forward pivot points 20 and 22. As head of set screw 150, FIG. 3 is turned counter clockwise, the angle between pivot points 20 and 22 at the forward portion of the suspension system is decreased thus providing for a firmer push-off force. This angle may be between 0 and 25 degrees. At the same time, the stiffness of resilient member 92 may be increased by turning head 128 of bolt 130. Such a position of truck 14 with respect to skate shoe 12 could be used in conditions where shock absorption is not critical, for example, on city sidewalks or on other paved or smooth surfaces. In these conditions, speed is usually the primary requirement and thus a firm forward push-off force is desirable. Rotating set screw 150 clockwise, however, increases the angle between pivot points 20 and 22 at the forward portion of the skate and rotating head 128 of bolt 130 in the other direction decreases the stiffness of resilient member 92 thus providing for increased shock absorption of the suspension system for conditions where an ultra-firm push-off force is not as critical and shock absorption is the overall consideration. Such conditions include off-road use and skating over irregular surfaces. The user tailors the shock absorption and push-off characteristics of the skate according to the users weight, skating ability, and the terrain. Truck 14 thus absorbs impacts by traveling up and down and/or in an arc like fashion relative to shoe 12. The unique four-bar linkage truck of the subject invention also allows for easier turning and braking. Again, the user tailors the resilency of member 92 and the angle between the pivot points to suit the skater&#39;s requirements. Fasteners such as allen head set screw 127, FIG. 3, provide a means for securing bolt head 128 to shaft 120 to prevent inadvertent turning of bolt head 128 during use. 
     Alternatively, the position of pivot point 20 relative to pivot point 22 could be fixed and not adjustable. Ledge 160 of member 16 cooperates with surface 162 as a stop to prevent forward motion of truck 14 relative to shoe 12. As shown in FIG. 4, shock absorber system 28a may simply include resilient member 170 removably fixed in place between truck mount 172 and shoe mount 174. In this design, a cost savings is realized by eliminating the pivots, bushings, and adjustment mechanism. 
     The distance between pivot shaft 20, FIG. 1, and shaft 24 is approximately 5.6 inches. Resilient member 92 is approximately 1.25 inches long and compressible to about 0.768 inches. 
     Another feature of the subject invention is brake shoe 200, FIG. 5 which is removably attached to the rear of the truck as shown via screws 202 and 204 and a set of two additional screws (not shown) on the other side of the truck. Unique to this invention is the ability for the potential purchaser to test the improved shock absorbintg characteristics of the skate in the showroom of the retail outlet by bouncing up and down on his heels. This eliminates the need to &#34;test drive&#34; the skates before purchasing them. 
     Although specific features of this invention are shown in some drawings and not others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. 
     Other embodiments will occur to those skilled in the art and are within the following claims: