Technical Field

The invention relates to a freewheel mechanism, specifically to a two directional freewheel rotary connection mechanism, used for example for tightening and loosening different sorts of screw connections, which comprises a body, one part of a rotary joint in whose opening the release element of the second part of the rotary joint is mounted.

State of the Art

Currently, a large number of freewheel design solutions are known which enable the blocking of backward movement of rotary connections, such as those which are in ratchets for loosening and tightening various types of screw connections throughout the field of machinery, for example in the car industry.

The most widespread are bi-directional ratchets, where a reversing lever is used to switch between tightening or loosening. The construction is mounted on a rosette with a catch which engages via a reversing lever. The rosette has a varying number of teeth along its circumference, largely from 36 to 72 teeth. This means that the minimum stroke in a ratchet with 36 teeth is 10° of wasted movement. For a ratchet lever 300 mm long, that is 58 mm. If we add the clearance between the head of a bolt and an extension that is loosely attached to the screw head, this will make the wasted movement much larger. The disadvantage is that, with such a ratchet it is only possible to work in accessible places with sufficient space to advance the ratchet by at least 1 tooth. The force transfer from the lever to the extension is only through a single catch, thus limiting maximum torque. In view of the above, this leads to rapid wear of the rosette and the catches, and thus to the breakdown of the entire ratchet.

Uni-directional sliding ratchets are also currently known. Tightening or loosening is selected by manually moving an element on the handle. This ratchet does not have a toothed rosette, with force transmission being provided by bodies stored within the casing, mostly rollers that rotate in one direction and during tightening lock into wedge-shaped spaces. This is the principle of a freewheel, or a uni-directional bearing. The disadvantage is that to change between tightening and loosening, you must first remove the attachment, turn the handle 180°, move the squared edges to the reverse side, re-attach the attachment, and then finally perform the appropriate operation. This can only be done with a straight handle. If the handle is adapted to fit the working area, for example, if it is bent, this system cannot be used. Although this ratchet can be used for work in tight spaces, in regard to the above-mentioned complex repositioning, work with it is complicated and very tedious. Additionally, this type of ratchet has roller bodies loosely stored in the wedge-shaped spaces, mostly without pressure or with forced compression by means of springs or rubber bands, which again means greater failure.

From CS patent 99226 a hydraulic-mechanical torque spanner is known, with a ratchet and a catch in which the ratchet is formed as a cylindrical body mounted to rotate in the body of the spanner, with a central continuous profiled opening for the spanner socket, the ratchet of which is composed of two parts rotatably on a common pin, which are connected to each-other flat to form an anti-pressure two- armed lever, between the teeth of the ratchet and the piston of the working cylinder in which there is an adjustable spring under the piston and a release opening, which is the location of the valve connecting the space under the piston of the working cylinder to the space under the piston of a second cylinder, forming a reservoir as well as an accumulator, and provided with a compression spring above the piston, which is for securing pieces of the catch when the ratchet is not engaged and a slidable pin against the pressure of its spring by a push-button mounted in the body of the spanner. The disadvantage of this is its complexity and tendency to break down.

From U.S. patent document 2919000 there is also known a uni-directional electromagnetically controlled coupling. Its disadvantage is its robust and relatively complex design.

From another patent document - US 5390773 there is known a bicycle clutch which comprises an external rotor and an internal rotor, where three sockets are arranged on the inner rotor, with only a single magnet located at the bottom of the socket. This is essentially a classic freewheel that is practically usable only in the design for a bicycle.

It is apparent from the above-mentioned currently known technology that the main disadvantage of existing freewheel mechanisms is that their locking against backward movement is with free play, while switching direction of the freewheel mechanism is very complicated and time-consuming.

The object of the invention is to construct a freewheel mechanism which is of simple design, free from play, and that will allow a simple and rapid change of the direction of the freewheel mechanism.

Principle of the Invention

The mentioned deficiencies are to a large part removed and the objectives of the invention fulfilled by a freewheel mechanism, specifically a bi-directional freewheel mechanism of a rotary connection comprising a body, the first rotary part in whose opening is the release element, in which the second part of the rotary connection is set, according to the invention, characterised by that in at least one socket is arranged on the surface of the release element, and that on each side of the socket there is a storage space in which at least one magnet is arranged, while there is a cylindrical roller in each socket. The advantage of this is that it is created using the magnetic field without free play of the connection of the two rotating components. The magnitude of the transmitted torque can be set by varying the strength of the magnetic force of the magnets or by varying their number.

To advantage, at least three sockets are arranged on the surface of the release element and they are evenly spaced. The basis is that the more sockets and magnets placed therein located on the surface of the release element, the greater the torque the connection created is able to transfer.

It is also to great advantage if the roller is arranged in a wedge-shaped space which forms the straight bottom of the socket and the arched surface of the opening of the body. The advantage is the precise determination of positioning.

In the most advantageous embodiment, the roller is arranged in the wedge- shaped space so that the minimum distance from any one of the magnets is 0.2 mm. The advantage being the optimisation of power ratios.

It is to further advantage if on the body there is a support ring provided which includes at least one opening in which the end of the roller is stored, while in the most advantageous embodiment the support ring is arranged to be movable and is compressed by a lid which is fixed in the opening of the release element. It is to advantage that by means of the moveable ring, it is possible to change the direction of the locking movement, for example if this design is used for a ratchet, it is thus possible to select either tightening or loosening, which is achieved with help of the support ring, the rollers are moved into a position where they are under the corresponding effect of the magnetic field of the magnets located on one of the sides of the socket. Changing this position can also be accomplished remotely without using the carrier ring by means of another connected control mechanism.

It is to great advantage if the support ring is non-magnetic.

From the point of view of optimal functionality, it is to further advantage if the opening in the body is made with a tolerance of ± 0.02 mm, and if the socket is made with a tolerance of ± 0.02 mm. The advantage is high accuracy of function and minimisation of wear and tear. At the same time, it is to great advantage if all functional parts are manufactured with high precision.

It is also to advantage if the socket has a bottom which is parallel to the tangential opening in the body perpendicular to the axis of the socket. This makes it possible to create a very precise double-sided wedge-shaped strut.

It is further to advantage if the roller is made of a magnetic material.

It is to great advantage if the roller is manufactured as case hardened.

From the point of view of the simplicity of the whole design, it is also to advantage if the lid is fixed to the opening of the release element by pressing.

The main advantage of the freewheel mechanism according to the invention is that it is free from play. Magnets attract the rollers by means of a contactless magnetic pole, thus defining without free play the wedge-shaped space between the engaging element and the body. This allows for single-sided torque transfer. On the other hand, the ability to rotate freely is possible because the magnets on the opposite side of the socket do not act by magnetic force and are, therefore, inoperative if the setting is not changed. A further advantage is that the freewheel mechanism, according to the invention, makes it possible to use the one-direction bearing principle, certainly it is possible to choose the direction of rotation, both turning to the left and turning to the right. If the freewheel mechanism is used with a ratchet, it is possible to tighten or loosen a bolt without free play, with a single placement, and at a minimum of stroke and, for example, when the support ring is locked, loosen a blind-headed bolt by using a swinging movement. It is to great advantage if the freewheel mechanism is used in a ratchet for use in very confined spaces, for example when adjusting the geometry of the rear axles of cars, where the ratchet handle is typically bent several times in trying to reach a bolt located in a very tight space.

Overview of the Figures

The invention will be further elucidated using drawings, in which Fig. 1 and Fig. 2 show a frontal view in cross section of an arrangement of the freewheel mechanism in both its extreme positions, Fig. 3 is a spatial view of a ratchet with a freewheel mechanism and a release element comprising a hexagonal space; Fig. 4 is a spatial side view of the support ring and lid of a ratchet with a freewheel mechanism, Fig. 5 shows a spatial cross-sectional view of the freewheel mechanism used in the ratchet, Fig. 6 shows a spatial view of the spatial break-down of the individual components of the freewheel mechanism used in the ratchet.

Examples of the Performance of the invention

The bi-directional freewheel mechanism (Fig.1, Fig. 2) of a rotary connection is arranged on a ratchet (Fig. 3, Fig. 4, Fig. 5, Fig. 6) for tightening and loosening screw connections.

The bi-directional freewheel mechanism comprises a body 1, the first part of the rotary connection, in the opening 8 of which is an release element 2, the second part of the rotary connection.

The release element 2 (Fig. 3) comprises a hexagonal shaped space 7 for receiving a fastener such as a nut or bolt head.

On the surface of the release element 2 are mounted five milled sockets 9 which have, on both of their sides, a storage space 10 in which magnets 5 are arranged, while in each of the sockets 9 is provided likewise with a movable roller 4 made from case hardened magnetic material.

The opening 8 of the body 1 and the socket 9 are manufactured with a tolerance of ± 0.02 mm.

Each socket 9 has a bottom H which is parallel to the tangential opening 8 of the body 1 perpendicular to the axis of the socket 9. Each of the rollers 4 is arranged in a wedge-shaped space 13 which forms the straight bottom H of the socket 9 and the arched surface 12 of the opening 8 of the body 1

Each of the rollers 4 is arranged in the wedge-shaped space 13 so that the minimum distance from any one of the magnets 5 is 0.2 mm.

On the body 1 (Fig. 4, Fig. 6) there is also located a non-magnetic support ring 3 which comprises five openings 14 in which the ends of the rollers 4 are stored.

The movable support ring 3 is provided with an indentation 16 that and is compressed by a lid 6 which is fixed in the opening 15 of the release element 2. The lid 6 is fixed in the opening 15 of the release element 2 by press.

The bi-directional freewheel mechanism arranged on a ratchet is operated so- by first moving with the support ring 3 the rollers 4 to the respective sides of the sockets 9 and thereby moving them into the forces of the respective magnets 5. The magnets 5 draw the rollers 4 by means of a contactless magnetic pole and thus define without free play the wedge-shaped space 13 between the engaging element 2 and the body I- This allows torque to be transmitted while on the opposite side the ratchet moves freely because the magnets 5 on the opposite side of the sockets 9 do not act by magnetic force and thus are inoperable until the time of change of purpose.

Industrial Application

The freewheel mechanism, according to the invention, can be used as a bidirectional freewheel mechanism in rotary connections applicable to any industrial applications where uni-directional short-term forced movement is needed and the remainder of the of the strokes are free inertial movement, the same going on the other hand as selected, as a freewheel mechanism for ratchet rotation for the tightening and loosening of screw connections, and as right-hand and left-hand spinning crank mechanisms, such as starters.