The present invention relates to a roller skate, comprising a sub-frame intended for the bearing of a shoe; at least one rear wheel situated at the rear side of the sub-frame and connected thereto; a pair of mutually tracking front wheels which are attached for free turning to a rocking arm connected for rocking to the front side of the sub-frame; and braking means.

Such a roller skate is known from US-A-4.382.605. This known roller skate comprises rocking arms which are connected to the sub-frame via a flexible suspension so that in the case of sideways pressure the rocking arm wheels assume a mutual steering position, this such that the steering direc¬ tion follows the exerted sideways force, which makes a strong sideways push-off impossible. The sub-frame moreover protrudes so far over the foremost and rearmost roller skate wheels that when the roller skate tilts forward the foremost roller skate wheel brakes and when the roller skate tilts backwards the rearmost roller skate wheel is braked. This can give rise to very undesirable situations since if a skater stumbles the roller skate is more forcefully and even permanently braked.

The invention is has for its object to provide a roller skate that does not possess the aforementioned draw¬ backs. In particular, a braking system is provided which has so-called anti-blocking properties. This is achieved according to the invention in that the roller skate comprises a sub- frame intended for the bearing of a shoe; at least one rear wheel situated at the rear side of the sub-frame and connected thereto; a pair of mutually tracking front wheels which are attached for free turning to a rocking arm that is rigid in sideways direction and connected for rocking to the front side of the sub-frame; and a brake member which is attached to the sub-frame such that through the forward tilting of the sub-frame the brake member makes contact with the rear front whee1.

In this way a brake is provided for such a roller skate which improves safety and enables maximum control. The rearmost of the pair of tracking front wheels is now braked while both the front wheels maintain contact with the ground and stay on course. When excessively hard braking or even blocking takes place, the sub-frame tilts further forward, with the result that the rearmost braked front wheel leaves the ground and the braking action disappears until the balance is restored. The braking member possesses anti-blocking bra- king properties.

Should the brake member be provided with adjusting means for the adjustment of the angle of tilt of the sub- frame whereby the brake member takes grip, it is ensured that during the end of a skating movement, for example when sprinting and skating fast, that a good push-off is possible with a maximum leg spread. In this situation the heel is in any case slightly raised from the ground and the front side of the roller skate is used for more forceful push-off. In order to avoid the brake applying too early during this til- ting movement it is desirable to make the angle of tilt of the sub-frame at which the brake member takes grip adjustable relative to the ground.

If the pair of rear wheels is attached for mutual tracking and free turning to a rocking arm connected for rocking to the rear side of the sub-frame, a roller skate is provided with four mutually tracking wheels, with the result that the roll-resistance is very small. Because of the high speeds to be achieved therewith and in combination with the reduced tendency to stumbling for both the front side and the rear side of the roller skate and the shock balancing, the roller skate is very suitable for long trips on uneven paving.

If more preferably a brake member is attached to the sub-frame such that as a result of backward tilting of the sub-frame the brake member makes contact with the rearmost rear wheel, the roller skate acquires an optimally control¬ lable braking potential because in the case of too hard bra¬ king the brake action is reduced or even disappears because

the sub-frame once again tilts forward.

If in a rocking arm the distance from the rocking arm-rotation point to a foremost wheel is greater than the distance to the rearmost wheel, the risk of stumbling is optimally reduced because for the negotiation of an uneven surface a greater moment force can be generated by the fore¬ most wheel of the rocking arm.

In the case that a resetting spring constrains the rocking arm to a neutral position wherein the rocking arm extends under the sub-frame and largely parallel thereto, it is ensured that when contact is made with the ground the rocking arm is already in or close to its neutral position, which improves the steerability of the roller skate. A fine adjustment may optionally be present. If in preference an inclination limiter bounds the angle of inclination of the rocking arm relative to the sub- frame the advantage is achieved that the foremost wheel of the rocking arm, when passing over a hole, does not incline too far forwards in a downward direction relative to the neutral position so that when passing over holes a more uni¬ form riding behaviour results. It is moreover possible with the inclination angle limiter to tilt the foremost wheel of the foremost rocking arm upward relative to the neutral posi¬ tion as a result of which the tracking roller skate wheels lie on a circular arc with a large radius and an easily steer- able skeeler is produced. The upward movement of the foremost rocking arm is not hereby limited so that the braking action, the anti-stumbling effect and the push-off movement are sub¬ stantially not negatively influenced. According to another embodiment the roller skate according to the invention is further provided with a pair of rear wheels on a common steering rear shaft. This very ver¬ satile, stable roller skate with a good push-off grip _, is especially suitable as roller hockey skate. If more preferably the steering deflection of the steering rear shaft is adjus¬ table with adjusting means the steering deflection of the

steering rear shaft can have stepless adjustment, for example to a turning circle of circa 2.6 metres.

For braking action it is advantageous that this embodiment of the roller skate is provided with a brake-wheel which protrudes between and behind the pair of rear wheels above a surface.

Mentioned -and other features of the roller skate accor¬ ding to the invention will be elucidated hereinafter in the appended description, whereby reference is made to the annexed drawing. In the drawing:

Fig. 1, 5 and 7 each show a view of the roller skate according to the invention; fig. 2, 6 and 8 show a bottom view of the roller skate from fig. 1, 5 and 7 respectively; fi _* 3 and 4 are each a schematic drawing showing the braking action of the roller skate from fig. I; fig. 9 is a drawing corresponding with fig. 3 which shows the braking action for the roller skate from fig. 7; and fig _* 10 is a drawing of a variant of the roller skate from fig. 7.

Fig. 1 and 2 show a roller skate 1 according to the invention. The roller skate 1 comprises a sub-frame 3 to which a shoe 5 is attached by fastening means 4. The sub-frame 3 comprises a toe-support plate 6 with bent over edges 7, 8 and 9, 10. In a similar manner a heel-support plate 11 is provided with bent edges 12 and 13.

The edges 9 and 10 are provided with slotted holes 14 which co-act with holes 15 arranged in the edges 12 and 13, which enables a length adjustment of the sub-frame 3 using the bolts 16 inserted through the slotted holes 14 and holes 15 and spacer tubes. The mutually tracking front wheels 17 and 18 are attached to a rocking arm 21 for free rotation around the respective wheel shafts 19 and 20. The rocking arm 21 is constructed from two rocking arm parts 22 and 23 which, using bolt connections 24 and 25, are attached for rocking to and between the bent over edges 7 and δ.

In a similar manner the rear wheels 26, 27 are attached to a rocking arm 30 for free rotation around the wheel shafts 28 and 29. The rocking arm 30 consists of two rocking arm parts 31 and 32 which are connected using bolt connections 33 and 34 for rocking on and between the bent over edges 12 and 13.

Arranged on the front side of the sub-frame 3 is a brake member 35 for the pair of foremost wheels 17 and 18 while on the rear side is arranged a brake member 36 for the rear wheels 26 and 27. The action of the brake members will be explained with reference to figs. 3 and 4.

Fig. 3 shows the action of the foremost brake member 35. This brake member is fixed to the sub-frame 3 such that when the roller skate 1 tilts forward, whereby the rear pair of wheels 26 and 27 leave the ground 37, through a tilting of the rocking arm 21 around the rocking shaft 25 the rearmost front wheel 18 is pushed against the crescent-shaped brake surface 38 and the rearmost front wheel 18 is braked.

Fig. 4 shows the brake action of the brake member 36. This brake member is fixed to the sub-frame 3 such that when the sub-frame 3 tilts backward the brake member 36 makes contact with the rearmost rear wheel 27, because during the tilting the rocking arm 30 tilts around the rocking shaft 34. Fig. 5 and 6 show a variant in the form of the roller skate 2 according to the invention. The foremost por¬ tion of the roller skate 2 is identical to the roller skate 1 so that with respect to this construction reference is made to fig. 1-4. Arranged for tilting between the bent over edges 40 and 41 of the heel-support plate 39 in slotted holes 46 and 47 is the tilting chassis 42 for the rear wheels 44 and 45 arranged on a common steering shaft 43. In this way the steer¬ ing deflection of the steering wheel-shaft 43 is adjustable. A fork 48 in which the steering wheel shaft 43 is bearing mounted is connected to the chassis on the one side via a rubber spring bearing 50 pulled against the chassis with a

bolt connection and is mounted on the other side with a pro¬ jection 51 in a bearing groove 52 of the chassis 42. Accor¬ dingly the fork with rear shaft is rotatable relative to the tilting chassis along the dashed line (centre spring bearing- centre projection) for steering deflection.

In the position drawn in fig. 5 a maximum steering movement is possible, while as a result of clockwise turning of the chassis 42 this steering movement is reduced or even disappears in the most extreme position. The bent over edges 40 and 41 are extended towards the rear and form side pieces 53 and ^' 54 between which a defor- mable brake wheel 57 is fixed on a sleeve 56 using a bolt connection 58.

By tilting the sub-frame 3 backwards the brake wheel makes contact with the ground 37 and as a result of deformation will make braking contact with the side pieces 53 and 54, resulting in an adjustable braking action.

Fig. 7 and 8 show a roller skate 59 according to the invention whereby one rear wheel 60 is attached for free turning to the sub-frame 3. The front wheels 17 and 18 are attached for free turning to an asymmetrical rocking arm 61 which means that a distance A from the rocking arm-rotation point 62 to the foremost wheel shaft 19 is greater than a distance B from the rotation point 61 to the rearmost wheel shaft 20.

Using a resetting spring 63 the rocking arm 61 is constrained into a neutral position wherein the rocking arm 61 extends substantially parallel to the sub-frame 3 or to a ground surface 37. A spring leg 64 of the spring 63 is fixed to the wheel shaft 20 via a rotatable disc 65. A movement of the disc 65 in the direction of the double arrow 66 enables a fine adjustment of the neutral position because the other spring leg 67 is non-rotatably fixed to the sub-frame via a clamping disc 68 which is fastened to the rocking arm shaft 62.

An inclination limiter 69 is slidably attached to the sub-frame 3 with a bolt guided into a slotted hole 70.

Through sliding of a stop surface 72 of the inclination limi¬ ter 69 toward or away from the rocking arm 61 the diving angle, that is, the angle of tilt of the rocking arm 61 around the rotation point 62, is bounded.

If as shown in fig. 10 the inclination angle limiter 69 is placed into its extreme forward position the rocking arm 61 is tilted such that the wheels 17, 18, 73, 74 and 60 lie on a circular arc 75.

Finally, the roller skate 59 is provided with a brake member 76 which is fastened to the sub-frame 3 using adjusting means 77 such that the tilt angle of the rocking arm 61 , whereby the brake member 67 grips on the rearmost front wheel 18, is adjustable (see fig. 9). To this end a brake wheel holder 78 is rotatably guided with a setting bolt 79 in a curved slotted hole 80 around the rotation point 81 of the wheel holder 79.

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