US3425706A

US3425706A - Ski pole wheel

Info

Publication number: US3425706A
Application number: US577460A
Authority: US
Inventors: Torsten Erland Folke Lindberg
Original assignee: Sandvik AB
Current assignee: Santrade Ltd
Priority date: 1965-09-06
Filing date: 1966-09-06
Publication date: 1969-02-04
Anticipated expiration: 1986-02-04
Also published as: CH455603A; DE1578907A1; AT275378B

Description

Feb; 4, 1969 'r. E. F. LINDBERG SKI POLE WHEE L Filed Sept. 6, 1966 United States Patent Office 3,425,706 Patented Feb. 4, 1969 11,552/65 US. Cl. 280-11.37 Int. Cl. A63c 11 /24 3 Claims ABSTRACT OF THE DISCLOSURE A ski pole wheel consists essentially of a ring and a holder, within the ring, by which the ring is flexibly secured to a ski pole. The holder, in turn, comprises a central holder portion (comprising a hub, which accommodates a ski pole in an axial opening therein, and inner holder sections contiguous with the hub), outer holder sections adjacent to the ring of the ski pole ring and having outwardly directed holder arms, and portions interconnecting said inner and outer holder sections, said holder arms terminating in sleeves or fastening portions embracing the ring of the ski pole ring. The ring is formed, in one piece, of plastic material having relatively restricted flexibility while the holder is formed, in one piece, of a relatively soft and yielding plastic material. By situating the connections between the wheel and the ring and the outer holding sections in diflerent radial directions than the connections between the outer holding sections and the inner holding sections the ring is easily inclined (under influence of a load) from the normal position perpendicular to the axis of the hub whilst rapidly returning to normal position upon removal of the load.

The present invention relates to a ski pole wheel comprising a ring which is attached to a ski pole by means of a holder. Previously the ring has often been made of metal which has the defect that it is relatively heavy and susceptible to permanent deformation. The holder has been made of leather, rubber or similar material in order to give sufficient freedom of movement of the wheel relative to the pole, the ring being attached to the holder by rivets or the like.

The present invention provides an improvement of ski pole wheels consisting in that not only the ring but also the holder are made of plastic, the ring being made of a harder and less flexible plastic and the holder of a softer and more flexible plastic. This gives a substantially simplified construction of the wheel. The invention is described in the following specification and illustrated in the appended drawings in which:

FIG. 1 is a top elevational view of a ski pole wheel according to the invention, and

FIG. 2 is a section on line 22 of FIG. 1.

The ski pole wheel shown in FIGS. 1 and 2 comprises a ring and a holder 11 with a hub 12. The ring illustrated has a hexagonal cross section but may have some other section, for instance circular. The holder consists of inner holder sections 13 adjacent to the hub 12, outer holder sections 14 adjacent to the ring 10 and interconnecting portions 15. The outer holder sections 14 are in the form of radially directed arms which at their outer ends have fastening portions 16 embracing the ring 10. These fastening portions 16 are situated radially between the connecting portions 15, an arrangement which permits the ring to be easily inclined from its normal position in a plane perpendicular to the axis of the hub 12 under influence of a load and to rapidly return to said plane when the load is removed. The wheel has a high resilience and the deformations normally encountered are not permanent. The invention is useful also for other types of holders than the one described. The arms of the outer holder sections may be flat as shown in full lines for the arms 14 or corrugated as shown with dashed lines for the arms 14a in FIG. 2.

The fastening portions 16 are formed as sleeves which embrace the ring 10 and the ring is thus secured without use of rivets as has been usual in earlier constructions. It has unexpectedly been found possible to join a ring 10 of hard plastic and a holder 11 of softer plastic in this way in spite of the fact that the melting points of the plastics are rather close to each other. The invention provides thereby a substantial simplification of previous wheel constructions, as it is possible to make the wheel in two parts of different materials without riveted or similar joints. At the same time the wheel has a substantially smaller weight than previous wheels.

A substantial advantage of the present wheel is that all parts of it are resilient, at the same time as the materials in the ring and in the holder are adapted to suit the different requirements for said parts. As stated above it has earlier been known to make the ring portion of metal, but metal is susceptible to permanent deformation by mechanical impacts. It has further been suggested to make the whole wheel in one piece of the same plastic but this requires a hard plastic because a soft plastic would not be rigid enough for the ring. The hard plastic on the other hand is not sufficiently yieldable for the holder to permit the repeated angular displacement of the wheel on the pole during skiing. Therefore the hard plastic wheel has to be provided with a flexible joint between the wheel and the pole.

The invention solves these problems by providing a ski pole wheel which is flexible in both the ring and the holder between the ring and the pole and therefore not susceptible t0 shocks and which has a harder flexible ring providing the desired rigidity and a softer flexible holder providing the desired yieldability. This result is obtained as stated above by making the ring of a hard plastic and the holder of a soft plastic. The hardness of the ring is suitably 60-80 Shore, D-scale, usually about 70 Shore,

while the hardness of the holder is 20-50 Shore. Both the ring and the holder may be made of polyethylene, the ring being of HD-ethylene and the holder of LD-ethylene. A convenient material for the holder is ethylene-vinylplastic. In case the arms of the holder are corrugated as illustrated in 14a in FIG. 2, the plastic in the holder can be somewhat harder than if the arms are flat as illustrated at 14.

The radially directed arms of the outer holder sections 14 are provided with openings 17 to lessen their weight and also to increase their flexibility.

The hub 12 is integral with the rest of the holder, comprising the

parts

13, 14, 15 and 16. In some cases the hub may be omitted, the central part of the holder only having a hole for the ski pole.

When manufacturing the wheel the ring is cast in a first mold. A second mold for casting the holder is adapted in such a way that the ring can be mounted in the second mold before casting the holder. In this way the sleeves are cast around the ring each forming a unitary sleeve around the ring.

The wheel may be attached to the red by means of any suitable device as flanges on the rod on both sides of the holder centre. Another suitable fastening means is a separate rubber sleeve on the rod within the hub 12.

I claim:

1. Ski pole wheel comprising a ring and a holder, situated within the ring, by which the ring may be flexibly secured to a ski pole, said ring being formed in one piece of relatively hard plastic material and said holder being formed in one piece of relatively soft plastic material; said holder consisting essentially in (1) a central holder portion comprising a hub and inner holder sections connected thereto, (2) outer holder sections adjacent to said ring, and (3) portions connecting said inner holder sections with said outer holder sections; said outer holder sections including outwardly directed arms, the ends of said holder arms forming sleeves each of which embraces the ring, each sleeve forming a unitary annular section around the ring; the connections between the inner holder sections and the outer holder sections being situated in different radial directions than the connections between the outer holder sections and the ring. 2. Ski pole wheel according to claim 1 in which said outer holder sections are in the form of pairs of radially directed arm portions which generally lie in the same plane as the ring and converge from the inner holder sections towards the sleeve.

3. Ski pole wheel according to claim 2 in which said arm portions are corrugated in the radial direction.

References Cited UNITED STATES PATENTS 2,721,084 10/1955 Weiss 28011.37 3,193,300 7/1965 McDonald 280-1137 3,202,436 8/1965 Barreca 280-1137 FOREIGN PATENTS 489,888 1/1954 Italy. 201,848 2/1966 Sweden.

LEO FRAGLIA, Primary Examiner.

MILTON L. SMITH, Assistant Examiner.