The subject of the invention is a unidirectional toothed coupling which can be used in equipment in which it is necessary to couple shafts in one direction.

Unidirectional couplings are devices which enable transmission of motion and torque in one direction and allow disconnection of shafts when the direction of torque or relative rotary motion changes to the opposite. There are many designs of unidirectional couplings. From patent description PL289756A, a unidirectional coupling is known provided with two coaxial sleeves with a cage located between them, which forms a monolith with the shaft on which the coupling is seated, whereby on the external surfaces of both sleeves, in proximity to their adjacent end faces, there are recesses provided for rollers placed in the cage, and on the external splined surfaces of both sleeves, there are sliding discs mounted, on the end faces of which there are the teeth of front gears engaging with the cuts between the teeth made in the faces of a ring placed between such discs, and on the internal surface of said ring, there are also recesses to house the rollers placed in the cage.

Small, standard unidirectional couplings available in the market can transmit only very low torque in a locked direction. With a toothed design, it is possible to increase the forces considerably. However, there is another problem related to the technical possibilities of making teeth of such a small size, ca. 1 mm and smaller. This increases the cost of such a coupling, or it cannot be made at all with conventional methods.

The coupling of the invention is a solution to the above problem.

The unidirectional toothed coupling, comprising the first coupling component with sliding fit to the second coupling component, and such components are seated on a shaft, whereby a bearing is located in the second coupling component, according to the invention, is characterised in that the first coupling component is close in shape to a truncated cone, the side wall of which is inclined in relation to its axis of symmetry at an angle of 0° < Ω < 90, and on that surface, there is at least one undercut, and in the second coupling component, there is a hole with a shape corresponding to the first coupling component, and the bottom of the undercut and its face are parallel.

Preferably, the shape of the first coupling component (1 ) is described by the following equation with pole coordinates:

z=f(z,tg(Q))

0=f(0)

p=f(0,z,n)

where:

n - number of teeth, where neN_+

z - height, where zeR

0 - angle, where 0GR is in a range of Ο≤0≤2π

p - guiding vector, where peR

d - tooth height, where deR Ω - main surface inclination angle, where QeR is in a range of Ο<0<π/2

β - inclination angle of the undercut surface (1a), where $eR in a range of -ττ/2≤0<ττ/2

φ - projection angle of the undercut end (1a) on the main axis, where cpeR and is a function φ=ί(ρ,β) with a constant value of (p=CONST,

whereby:

f(z),f(0) - are functions with a linear character

f(0,z,n) - is any function which is repeated on the circumference as many times as there are undercuts (1a), and where the following condition is met:

f( ^-2 n(k-2),z,n)-f(0-9-2n/n(k-1 ) _> z,n)=d

for ke(1 ,n) where keN.

Preferably, the working surface of the undercut of the first operating component is oriented clockwise.

Preferably, the working surface of the undercut of the first operating component is oriented counter clockwise.

Preferably, the first coupling component has two or three parallel undercuts. Preferably, the first operating component is active in relation to the second operating component. Such active components are the spring, electromagnet and electric drive.

The coupling, according to the invention, enables transmission of forces of rotary motion in one direction only, and decoupling occurs in the opposite direction. Decoupling in the reverse motion occurs due to forces oriented axially and away from the coupling. They result from transferring the torque by the inclined surface of coupling components. The aforementioned invention is presented in example embodiments in a drawing in which fig. 1 shows an exploded isometric view of the coupling; fig. 2 - assembled coupling in half- sections; fig. 3 - isometric view of the assembled coupling; fig. 4 - parametrised view of the first coupling component with two undercuts; fig. 5 and 6 show the first and second coupling components in an exploded and isometric view; fig. 7 - side view of the assembled first and second coupling components; fig. 8 - top view of the assembled first and second coupling components; fig. 9, 10 and 11 show the first coupling component with one undercut.

The unidirectional toothed coupling is composed of the first coupling component (1 ) fit snug to the second coupling component

(4) , and such components are seated on the shaft (5), whereby the bearing (2) is located in the second coupling component (4) and secured with the snap ring (9). The bearing (2) is seated on the shaft

(5) and secured with the retaining plate (7), and on the shaft (5), the trigger (8) is mounted. On the shaft (5) and the trigger (8), the first coupling component (1) is fitted and it is fit snug to the shaft (5) and trigger (8). The first coupling component (1 ) is pressed with the active component (6) in the form of a spring. The active component

(6) causes the first and second coupling components (1 , 4) return to the coupled position. An electromagnet or electric drive can also be used as an active component. The first coupling component (1 ) is secured to the shaft (5) with the pad (3) and then with the retaining plate (7). The first coupling component (1 ) is close in shape to a truncated cone, the side wall of which is inclined in relation to its axis of symmetry at an angle of 0° < Ω < 90, and on that surface, there are two parallel undercuts (1a). In the second coupling component (4), there is a hole in a shape corresponding to the first coupling component (1 ), and the bottom of the undercut and its face are parallel. In an example embodiment, the working surface of the undercut (1a) of the first operating component (1) is oriented counter clockwise. It can also be made so as to be oriented clockwise.

In another example embodiment, the first coupling component (1 ) is used with one undercut (1a). According to the research completed, the coupling may have one or more undercuts; however, one undercut causes formation of great radial forces and consequently leads to radial run-out of the bearings. Two or more undercuts are recommended.

The shape of the first coupling component (1 ) is described by the following equation with pole coordinates:

z=f(z,tg(Q))

0=f(0)

p=f(0,z,n)

where:

n - number of teeth, where neN_+

z - height, where zeR

0 - angle, where 0eR is in a range of Ο≤0≤2π

p - guiding vector, where peR

d - tooth height, where deR

Ω - main surface inclination angle, where OeR is in a range of O<0<†r/2

β - inclination angle of the undercut surface (1a), where pGR in a range of -π/2≤0≤π/2

φ - projection angle of the undercut end (1a) on the main axis, where (peR and is a function φ=ί(ρ,β) with a constant value of (p=CONST, whereby:

f(z),f(0) - are functions with a linear character

f(0,z,n) - is any function which is repeated on the circumference as many times as there are undercuts (1a), and where the following condition is met:

f(0-(p-2n7n(k-2),z,n)-f(0-(p-2TT/n(k-1 ),z,n)=d

for ke(1 ,n) where kEN.

The coupling of the application was made utilising electro- erosion methods, in particular with wire cutting machines. This is not possible in the case of conventional unidirectional toothed couplings (Ω ^« 90 ^° ). It is also possible to make couplings with other methods, e.g. injection of plastics, but they will not be as strong as ones made of metals.