EP0077313A1

EP0077313A1 - Flexible slalom pole

Info

Publication number: EP0077313A1
Application number: EP82850199A
Authority: EP
Inventors: Kjell Lindskog; Johan Thorsten Hellzen
Original assignee: LINDSKOG Kjell Jan-Erik
Current assignee: LINDGREN, LARS; LINDSKOG Kjell Jan-Erik
Priority date: 1981-10-13
Filing date: 1982-10-12
Publication date: 1983-04-20
Also published as: DE3275814D1; EP0077313B1

Abstract

An article springing back after bending, for example a post, marking stick, slalom gate pole, muscle training appliance a.s.o., which comprises a flexible joint of the kind permitting bending of the article and return of the same to its original position, and which comprises at least two portions, which are rigidly or detachably connected each with a portion of the article or formed integral each with a portion of the article, which portions are resiliently held together by a spring force acting within the portions. In order to effact a certain delay of the return of the article after bending, the joint comprises between said portions (4a, 4b) a joint body in the form of a helical spring (3, 27), through which a connecting member (7) extends, and which is exposed to said spring force (11) at least when the stick is exposed to bending.

Description

This invention relates to an article, for example a post, marking stick, slalom gate pole, muscle training appliance etc., comprising a flexible joint of the kind permitting the article to bend in the desired direction and after bending to return to its original position. The article according to this invention is especially intended for use as a slalom gate pole, but can advantageously also have the form of an appliance for muscle training. It can, of course, also be used in many other fields where there is demand for flexible, self-erecting or spring-back resilient sticks or poles, for example in the traffic field to carry e.g. traffic signs, for lighting fittings and the like and for marking the edges of a roadway.
Road marking poles and slalom gate poles of flexible design are previously known. They are provided with a ⁱflexible joint, which is formed of a helical spring or of a body consisting of an elastic material, such as rubber. Flexible articles of this kind have the advantage, that they give way when being run into or when subjected to other effects, and thereafter stand up to their original position without any external help. These known marking sticks, however, return to their original position very fast and much too fast for being capable to advantageously act as a slalom gate pole. Owing to the fast return movement, the slalom skier cannot pass the pole before it springs back, but is hit by the same. The force of the spring-back movement is relatively strong, and such a stroke by the springing-back pole can cause the skier to get out of balance entirely or partially. A further disadvantage of these known spring--back slalom gate poles and other flexible marking sticks is that their return to original position is followed by subsequent vibrations, which in many cases can be irritating.
The present invention, therefore, has the object to produce a flexible article of the aforesaid kind, and especially a slalom gate pole, which does not involve the aforesaid disadvantages, but has a, so to speak, delayed return movement and built-in vibration damping.
For achieving this object, the article according to the present invention has been given the characterizing features defined in the claims.
In the following, some embodiments of this invention are described in greater detail by way of example and with reference to the accompanying drawings, in which

Fig. 1 is a section through a slalom gate pole with a flexible, spring-back joint according to the invention,
Fig. 2 is a section through an alternative clamping of the present joint in an article,
Fig. 3 is a section through a portion of a muscle training appliance comprising a joint of the kind shown in Fig. 1,
Fig. 4 is a section through a further developed embodiment of a brake or locking device shown in Fig. 3 and comprised in the joint,
Fig. 5 is a section on an enlarged scale through an alternative embodiment of a joint comprised in a marking stick according to the invention,
Figs. 6-9 are sections through different embodiments of joint bodies comprised in said lastmentioned joint,
Figs. 10-12 are partial sections through further alternative embodiments of the joint proper,
Fig. 13 is a partially sectional view of a slalom gate pole with double joints, and
Fig. 14 is a section through a joint according to the invention equipped with a locking device.

In Fig. 1 an article 1 according to the invention is shown comprising a joint 2 and having the form of a slalom gate pole or other kind of marking stick. The artcle 1 comprises at least two portions 1a and 1b, between which the joint 2 is located, and which may consist of a plastic material, but any other material, for example rubber, wood or metal, may be used for said portions la,lb. In a slalom gate pole the joint 2 is located closer to the lower end of the pole than to the upper end thereof, as shown in Fig. 1, but the position of the joint, of course, can be varied from one article to another and must be adapted to the function and purpose of the article, in which the present joint 2 is comprised as an essential part.
At the embodiments shown in the drawings, the joint proper 2 comprises a joint body 3 in the form of a helical spring of a spring wire 3a with square cross-section, and two opposed mounting sleeves 4a,4b each located on one side of the joint body 3, against which sleeves the spring 3 abuts with its ends. The mounting sleeves 4a,4b are formed each with a shell surface 6, which constitute a holder for the intended portion 1a or 1b, and with which, more precisely, the intended portion 1a,1b can be retained detachably by friction or by connection in another suitable and expedient way.
Through the joint body, i.e. the spring 3, and the mounting sleeves 4, a flexible connecting member 7 extends for holding together the mounting sleeves 4 and spring 3. When the spring is not affected, its turns abut or are adjacent to each other. Said connecting member 7 may be a chain, steel wire, for example piano wire, wire, plastic rod, rubber wire or the like. The connecting member 7 can be enclosed by a hose coil wound tightly, for example, of a spring steel wire or plastic wire, in order when desired to increase the diameter of the connecting member so that no lateral play can occur between the hollow joint body 3 and the connecting member 7. Instead of, or in combination with such a protection, or a protection of some other kind about the connecting member 7 a number of stacked, relatively short distance sleeves 40 with suitable material thickness can be arranged in the space between the joint body 3 and the connecting member 7 in order to reduce or adapt the size of said space. These distance sleeves 40 have an outer diameter, which is only slightly smaller than the inner diameter of the joint body in order also to act as a guide for the joint body, i.e. the spring 3, so that its different turns cannot be displaced in lateral direction relative to each other, but are maintained in place even when the spring 3 is bent.
The connecting member 7 is at least at one end formed as or provided with a threaded portion 8, which carries a washer 9 and at least one nut 10. A spring 11 is clamped between said washer 9 and the adjacent mounting sleeve 4a. At its other end portion, the connecting member 7 at the embodiments shown in the drawings is clamped firmly, and at the embodiment according to Fig. 1 it is formed as or provided with a conic anchoring portion 41, which is located in a corresponding conic seat 42 in a holder 43. Said holder rests against a shoulder 44 formed in the mounting sleeve 4b and is located within the mounting sleeve 4b.
At the embodiment shown in Fig. 2 said other end portion of the connecting member 7 is formed as a threaded portion 45, which extends through the holder 43 and carries a nut 41, which is conic at one end and acts as an anchoring member, and which has its seat 42 in the holder 43. Said holder 43 is guided at the end of the portion 1b and rests against tze end surface of said portion with a peripheral edge surface 4b. The holder 43 also can be formed so as with its end surface 47 to rest directly against the end surface 48 of the mounting sleeve. By this embodiment the advantage is gained that the tension of the spring 11 can pe adjusted from outside by the nut 41 without having to Dismount the article, which however is the case at the embodiment shown in Fig. 1..
The spring 11 comprised in the joint 2, thus, co-operates with the connecting member 7 and exercises a force adjustable in size, which tends to compress the spring 3 acting as the joint body, in that the connecting member 7 is flexibly and movably attached relative to the article and thereby renders it possible to bend the article in all directions against the action of the spring 11, which during the bending of the article is stretched additionally and is charged in order together with the spring 3 to return the article 1 to its original position as soon as the force bringing about the bending ceases. The kinetic energy at the return movement is taken up to a certain extent by the spring 11 every time it assumes the position shown in Fig. 1, so that no appreciable after-vibrations occur, but a certain damping of the vibrations is obtained.
In order to additionally increase the damping of vibrations at the return of the article from outward bent position and to effect delay of the return movement of the article from outward bent position, one or several elastic brake means 49 are provided to co-operate with the inner surface of the article. Each of said means 49 consists of an elastic member, for example of rubber, and is movable on the connecting member 7 between the washer 9 and a washer 50 abutting the nut 10. Said elastic members are formed so that they contact more or less with their peripheral surface 51 the inner surface of the article 1. The contact pressure of the members against the inner surface of the article in the original position of the article, i.e. in the position shown in the Figure, is adjustable according to demand by means of the nut 10 at the embodiment shown in Fig. 1, and by means of the nut 41 at the embodiment according to Fig. 2, and by means of a wing nut 60 at the embodiment according to Fig. 3.
Upon bending of the article, the spring 11 is compressed and thereby increases its spring force, whereby the brake means 49 are compressed additionally, resulting in that their contact pressure against the inner surface of the portion 1a increases and gives rise to increased friction between the brake means 49 and the inner surface of the portion, which friction tends to counteract the sliding occurring between the brake means 49 and said inner surface both at the bending of the article and at its return from outward bent position. In this position the friction forces between the inner surface of the portion and the brake means 49 are the greatest at the embodiment shown in Fig. 1, and hereby the brake means bring about a delay of the return of the article from outward swung position, and at least at the beginning a slower return of the article to its original position. Thereby no after-vibrations occur, but the article assumes its original position almost directly.
The friction forces produced by the brake means 49 depend to some extent on the inner diameter of the article. By changing this diameter in one way or another along one or more of the sliding paths of the brake means, the arising friction forces can be controlled and adjusted according to demand and desire. One example thereof is shown in Fig. 3, where the portion 1a is provided with an internal construction in the form of a sleeve 53, which is stationary in the portion 1a and capable to co-operate with the upper brake means 49. Said sleeve 53 has a portion 54 with the same diameter and an end portion 55 with increasing diameter. These two portions have a total length corresponding substantially to the distance, through which the respective brake means 49 slides relative to the portion 1a at the bending of the article from the original position to the position of maximum bending, i.e. about 90° at slalom gate pole, and about 180° at a muscle training appliance. Such an appliance is illustrated schematically in Fig. 3. It comprises a joint 2 according to Fig. 3, though this is not shown. Upon bending the appliance, thus, the friction forces increase as long as the brake means 49 slides along the portion 54 of the sleeve, and thereafter, depending on the inclination of the end portion, remains constant or decreases. In the latter case some special delay of the return of the appliance to the original position is not obtained, which is not necessary, either, at an appliance of this kind. Said appliance, the joint of which (not shown in Fig. 3) is located between the two handle legs 1a and 1b of equal length, is provided at one end with a wing nut 60 co-operating with the threaded portion 45 of the connecting member, which nut contacts, preferably via a slide washer 61, a support plate 62, which in its turn rests against the mounting sleeve 46 via a distance sleeve 63. By means of this wing nut 60, thus, the desired resistance to bending can be adjusted.
In fig. 4 a constriction is shown schematically which has such a form as to bring about a special delay of the return of the article from a position swung outward at maximum, in that the brake means 49 first must pass the section top 56. The dashed line indicates the position of the brake means in relation to the constriction when the article is in its normal position, i.e. original position. This constriction section is suitable for a slalom gate pole, and by this section an extra initial resistance to the bending of the pole is obtained thanks to the section top 57 of the section. It appears from this, that the constriction can have or can be given any internal section shape suitable for the result desired. When several brake means are arranged, each of them can be provided with a constriction 53 having the same or different internal sectional shape relative to each other. It is suitable that the brake means 49. are slightly spaced from each other.
In Fig. 5 an embodiment of the present joint 2 is shown which comprises a number of joint bodies 3 with plane-parallel sides located concentrically between the mounting sleeves 4a,4b. These joint bodies 3 are held together with the mounting sleeves 4a,4b by the connecting member 7, which at this embodiment is under the action of springs 11, which are located one at each end of said member 7 and adjustable by means of a stop washer 9 and of nuts 10 located on threaded end portions 8 of the connecting member. Said springs co-operate with each other in order after the bending to return the stick with a certain delay to its straight original position without giving rise to any direct after-vibrations. This is due to the fact that the kinetic energy at the return movement is taken up to a great extent by the springs 11 when the joint bodies 3 during the return get parallel with each other, and by the friction between the joint bodies 3.
In order to additionally increase the damping of the vibrations at the return of the stick, a disc-shaped damping member 12 can be provided between one or several joint bodies 3, or between every joint body 3 and possibly also between the respective mounting sleeve 4 and adjacent joint body 3. Said disc-shaped member has a through hole for the connecting member 7 and is of a material, for example rubber, softer than in the joint bodies 3 and preferably with a smaller extension in axial direction than said joint bodies 3, which can consist of metal, plastic, preferably rigid plastic, hard rubber or the like.
The joint bodies 3 can be designed as plane-parallel discs of the kind shown in Fig. 7 or 8, or be provided with or formed as semi-spherical projections 13 on one side and corresponding semi-spherical depression 14 at its other end for hingedly receiving the semi-spherical projection 13 of the adjacent joint body with through hole 15 for the connecting member 7.Each joint body 3 provided with such projection 13 and depression 14 should have circular shape, but of course they may have another shape, for example be designed polygonal or square. When the stick is desired to be easier to be bent in two diametrically opposed directions, the joint bodies 3 may be given elliptic or rectangular shape.
The fit between projection 13 and depression 14 can be made relatively close in order to obtain friction forces, which delay the return of the stick after its bending, and which besides contribute to causing the stick to stand in upright position without after-vibrations.
At the embodiment of the joint 2 shown in Fig. 11 the connecting member 7 is a spring, which with prestress is clamped between the remote end surfaces 16 of the mounting Sleeves 4 by means of lock pins 16a abutting said end surfaces. The joint bodies in this case are a funnel-shaped extension 17 of each mounting sleeve 4, which extensions abut one another with their widest end surface. Between shoulders 18 in the respective mounting sleeve 4 a spring 19 is plamped which encloses the connecting spring 7 and acts as a damping means and counteracts the connecting spring at the return of the stick from bent position. Though not shown in Fig. 10, in the connecting spring 7 can be located an additional damping member in the form of a solid rod or a hose of elastic material such as plastic or rubber.
In Fig. 11 an embodiment of the joint 2 is shown which has the same kind of connecting member as the joint shown in greater detail in Fig. 10. The arrows 20 and 21 in Fig. 11 indicate that tensile or comperrsive forces can be used for holding together the joint. At this embodiment, a spring 23 is clamped compressed between flanges 22 each on one of the mounting sleeves 4a and 4b, which are provided each with a guide pin 24 each enclosing the spring 23. Between the end surfaces 25 of these two pins facing toward each other a joint body 26 of elastic material, for example rubber or plastic, is located. The spring 23 acts as a damping member at the springing-back after the outward bending of the stick. This damping member can, but must not be reinforced by a spring 27 between the end surfaces 25 of said guide pins and tightly enclosing the body 26, as shown in Fig. 11.
In Fig. 12 a joint is shown which comprises a joint body 30 of an elastic rubber-like material, which body with its end can be rigidly or detachably located in the respective sleeve or stick portion, which are held together by a connecting member 7 of a kind described previously. In this body 30 are provided, preferably at the outer portion of the body, through narrow steel pins 31, preferably of spring steel, which pins effect the spring-back resili- nce. These steel pins possibly may be located in channels made in the joint body, one or several pins located in each channel. 32 designates a number of rings surrounding the body 30 and acting as distance members between the ends of the stick portions facing toward each other in the cases when no mounting sleeves 4 are used, but the body 30 is inserted directly into and connected to the stick portions, with which also the connecting member 7 is connected.
In Fig. 13 a marking stick or slalom gate pole 1 is shown which comprises a joint 2 of one of the embodiments described above and an additional joint 38, which consists of a conic hole 36 in one end of an anchoring portion 1c which can be rigidly anchored in the ground or snow, and a corresponding conic projection 37 in the end of the stick or pole portion 1b remote from the joint 2. Said portions are held together by a rubber cord 38 clamped in the portions. This joint permits a certain bending of the stick 1, but when this is exposed to a predetermined load, the joint 35 is released and the portions la and 1b of the stick located above the ground are permitted to drop on the ground, but do not fly away, owing to the rubber cord 38. This kind of slalom gate pole, thus, can be anchored relatively firmly in the ground.
In Fig. 14 an embodiment of the present joint is shown, which has a modified brake or locking device 65 and a chain as connecting member 7 and the same joint body as in Fig. 1. The locking device 65 comprises a locking member 66, which is rigidly but detachably connected to, for example screwn on, an extension 8a of the threaded end portion 8 of the connecting member, and which comprises a number of outward springing fingers 67, which positively can be pressed in against the portion designated by 8a. These fingers 67 always tend to extend outward and thereby, in the normal unbent state of the stick, are in the position shown in Fig. 14, in which position they can but must not be held pressed against the inner surface of the stick. In this position, however, the fingers 67 of the locking member shall be turned with their end surface 68 and abut an end surface 69 of a sleeve 70, which may be connected to the inner surface of the stick, as shown in Fig. 14, or may be an extension of the mounting sleeve 4a and which shall have an inner diameter,, which is smaller than that of the stick but slightly exceeds the greatest outer diameter of the locking member.
In the position shown in Fig. 14 the fingers of the locking member abut with their end surfaces 68 the end surface 69 of the sleeve 70 and thereby constitute a lock, which prevents bending of the stick until the force grows so strong, that all fingers 67 of the locking member are pressed together against the threaded end portion 8a of the connecting member by co-operation between the end surfaces 68,69 facing toward each other. When these fingers 67 have been pressed in so much, that their end surfaces 67 are free from the end surface 69 of the sleeve, they are introduced into the sleeve 70, in which they can slide easily, and thereby do not longer constitute resistance to the bending of the stick. When the stick then returns, these end surfaces again are brought into the position relative to each other shown in Fig. 14, in which position they again co-operate with each other and thereby rapidly stop any kind of vibration of the stick. This locking device 65 thereby also acts as a vibration damping device. The end surface 68 of the fingers comprised in the locking member, as shown in Fig. 14, can be bevelled at the periphery, and also the end surface 69 of the sleeve can be bevelled at its inner periphery. By these bevell- ings the force can be adjusted with which the stick is desired to be bent. This has proved especially important at slalom gate poles, which thereby can be designed so as not to give way for small effects.

Claims

1. A marking stick, for example a slalom gate pole, road markibg post and the like, with at least one flexible joint of the kind permitting the stick to bend and subsequent to bending automatically to return the stick to the original position, and which comprises at least two portions each connected to a portion of the stick, which portions are held together movable relative one another by a preferably adjustable spring force acting against at least one of the portions, characterized in that between said portions (4a,4b) a helical spring (27) comprising several turns is located acting as joint body, through which spring extends a connecting member (7), and which are exposed to said spring force (11) at least when the stick (1) is exposed to bending.

2. A marking stick as defined in claim 1, characterized in that the spring (27) acting as joint body consists of spring wire with square cross--section.

3. An article as defined in claim 1 or 2, characterized in that through the joint body (3) and said portions (4a,4b) formed as mounting sleeves extends a connecting member (7), which is exposed to said spring force, which is effected by a spring (11) located between the connecting member (7) and at least one mounting sleeve (4a).

4. A marking stick as defined in any one of the preceding claims, where said spring force is brought about by at least one spring (11) acting against one of the portions (4), characterized in that the portions (4) located on both sides of the spring (27) acting as joint body consist of mounting sleeves (4a, 4b) with a bottom wall facing to the spring (27) acting as joint body and with a cylindric portion remote from the joint spring (27) for at least partially surrounding the connecting spring (11).

5. A marking stick as defined in claim 2,3'or 4, characterized in that the connecting member (7) shows a substantial intermediate space to the spring (27) acting as joint body.

6. A marking stick as defined in any one of the preceding claims 3-5, characterized in that the connecting member is a flexible member (7), for example in the form of a wire, chain, steel wire, plastic rod, rubber wire or the like.

7. A marking stick as defined in any one of the preceding claims, characterized in that it comprises at least one braking member (49), which at increased load brings about in co-operation with the inner surface of the stick friction forces for damping and delaying the return of the article to the original position after bending.

8. A marking stick as defined in any one of the preceding claims, characterized in that it comprises a release or locking member (65), which permits the bending of the stick first at a predetermined load.

9. A marking stick as defined in claim 7 or 8, characterized in that several such brake members (49) are provided.

10. A marking stick as defined in claim 7, 8 or 9, characterized in that for control of the friction forces the article on its inner surface and in the area of at least one braking member is formed as or provided with a constriction with suitable internal sectional shape.