Non-return rotation transmission device

Abstract

The non-return device for coaxial rotation transmission comprises two coaxial input and output shafts (2, 3), a frame (4) for guiding the rotation of the shafts (2, 3), and a locking element (5) biased to translate radially through a channel (31) in the output shaft (3) between a radially locked position and a radially unlocked position, in which the locking element (5) protrudes from the channel (31) to abut against the frame (4) and thereby prevent rotation of the output shaft (3), and in the radially unlocked position the locking element (5) is retracted to allow axial rotation of the output shaft (3), the input shaft (2) being provided with means (21) for radially switching the locking element between its locked and unlocked positions.

Description

[Technical Field]

[0001] The present invention relates to a rotational transmission device that allows for the transmission of unidirectional rotational motion from an input shaft to a driven output shaft.

[0002] The present invention aims to provide attachment for many existing rotary drive devices in one or two rotational directions. [Background technology]

[0003] Known devices for transmitting rotation that allow the transmission of unidirectional rotational motion from an input shaft to an output shaft are generally friction devices that hinder the operation of the system in which they are inserted and do not allow robust stopping elements in the rotation of the output shaft. Furthermore, known devices often require the input of external energy for their non-return function. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a non-return device for transmitting coaxial rotational motion between two shafts that overcomes at least one of the above-mentioned drawbacks and is entirely mechanical, combining the advantages of robustness, adaptability and compactness. [Means for solving the problem]

[0005] In view of the above, an object of the present invention is a non-return device for transmitting rotational motion comprising two coaxial input and output shafts, a frame for guiding the rotation of the shafts, and a locking element capable of radial translational movement through a channel in the output shaft between a locked position and an unlocked position, wherein in the locked position said locking element protrudes from said channel to prevent rotation of the output shaft and in the unlocked position the locking element is retracted to allow axial rotation of the output shaft, the input shaft being provided with means for switching the locking element between its locked and unlocked positions.

[0006] Preferably, the means for switching the locking element comprises a cam having a profile designed to move the locking element radially upon rotation of the input shaft.

[0007] For example, the cam may be provided on the male end of the input shaft, which male end engages the female end of the output shaft.

[0008] Advantageously, the input shaft comprises a step that abuts against a flat portion of the output shaft to rotate the output shaft, and the abutment of the step upon rotation of the input shaft is angularly coincident with the cam placing the locking element in the unlocked position.

[0009] According to one embodiment, the switching means of the locking element comprises an unlocking key sandwiched between the cam and said locking element, said key being translationally connected through a channel in the output shaft.

[0010] In one embodiment, the unlocking key is fully received within the channel of the output shaft in the unlocked position.

[0011] Advantageously, the device comprises elastic return means for the locking element to the locked position, which act upon compression and force said locking element towards the axis of the shaft against a cam or, where appropriate, against an unlocking key.

[0012] Preferably, the means for resilient return to the locked position comprises a spring connected to the frame.

[0013] Furthermore, the frame may comprise a passageway which coincides with the channel of the output shaft in the locked position, and the locking element and unlocking key are able to translate radially through said passageway (41) in the locked position.

[0014] The present invention also relates to a device in which the rotation of the output shaft by the input shaft and the movement to the unlocked position occur substantially simultaneously after the input shaft has rotated at least one-quarter of a turn.

[0015] The invention will be better understood by studying in detail some embodiments thereof, chosen in a non-limiting manner and illustrated in the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0016] [Figure 1A] 1 shows a non-return device for the coaxial transmission of rotation according to a first embodiment; FIG. [Figure 1B] FIG. 1B is an exploded view of the device of FIG. 1A. [Figure 2A] FIG. 1B is a longitudinal cross-sectional view showing the device of FIG. 1A in a locked position. [Figure 2B] FIG. 2B is a first cross-sectional view showing the locked device of FIG. 2A. [Figure 2C] FIG. 2B is a second cross-sectional view showing the locked device of FIG. 2A. [Figure 3A] FIG. 1B is a longitudinal cross-sectional view showing the device of FIG. 1A in an unlocked position. [Figure 3B] FIG. 3B is a first cross-sectional view showing the unlocked device of FIG. 3A. [Figure 3C] FIG. 3B is a second cross-sectional view showing the unlocked device of FIG. 3A. [Figure 4]FIG. 10 shows a second embodiment of a non-return device for the coaxial transmission of rotation. DETAILED DESCRIPTION OF THE INVENTION

[0017] FIG. 1 illustrates a non-return device 1 for transmitting rotary motion.

[0018] This device 1 is intended to transmit rotation between two shafts by implementing a non-return function, in other words a function that prevents the input shaft from transmitting rotation from the output shaft.

[0019] The non-return device 1 comprises an input shaft 2 and an output shaft 3 arranged coaxially, and a frame 4 for guiding the rotation of the shafts 2, 3.

[0020] The shafts 2, 3 can be inserted, for example, into an existing system (not shown) comprising a rotationally driven shaft and a driven shaft to which it is desired to add a non-return function, to which the input shaft 2 and the output shaft 3 are connected respectively.

[0021] The shafts are provided with means for mutual cooperation to transmit axial rotational movement from one to the other. The input shaft 2 is intended in particular to drive the output shaft 3.

[0022] For example, the input shaft has a male end 24 that mates with a female end 32 of the output shaft 3 .

[0023] As illustrated in FIG. 2A, the frame 4 can support and guide the rotation of the shafts 2, 3, for example by means of plain or rolling bearings.

[0024] A locking element 5 is inserted into a transverse channel 31 of the output shaft 3. The locking element 5 is radially translatable through said channel 31 between a radial position referred to as the locked position and a radial position referred to as the unlocked position.

[0025] 2A, 2B and 2C, the locking element 5 protrudes from the channel 31. It therefore abuts against the frame 4 and thereby prevents the output shaft 3 from rotating.

[0026] In the unlocked position illustrated in Figures 3A, 3B, 3C and 4, the locking element 5 is retracted and does not abut the frame, allowing axial rotation of the output shaft 3.

[0027] For example, the frame comprises a passage 41 into which the locking element 5 is retracted in the unlocked position. In the locked position, the passage 41 aligns with the channel 31 of the output shaft 3, and the locking element 5 can then be radially translated through said passage 41 to retract and allow rotation of the output shaft 3.

[0028] The input shaft 2 further comprises drive means for the output shaft 3 and radial switching means 21 for the locking element 5 between a radially locked and unlocked position through a rotational movement of said input shaft 2. In contrast, the output shaft does not have switching means for the locking element 5.

[0029] Rotation of the input shaft 2 drives rotation of the output shaft 3 and movement of the locking element 5 to the unlocked position substantially simultaneously.

[0030] 2B and 3B, the input shaft 2 is provided with, for example, a step 25 that abuts against a flat 33 of the output shaft 3 in order to rotate the output shaft 3. The coming into abutment of the step 25 upon rotation of the input shaft 2 angularly coincides with the placing of the locking element 5 in the unlocked position using the switching means 21.

[0031] For example, the switching means 21 of the locking element 5 comprises a cam 22 with a profile 23 designed to move the locking element 5 radially when the input shaft 2 rotates.

[0032] Advantageously, the cam 22 is provided on the male end 24 of the input shaft 2, said male end 24 being engaged with the female end 32 of the output shaft 3. The cam 22 engages in the output shaft, thereby pushing the locking element 5 radially from the inside of the channel 31 towards the outside of the output shaft 3.

[0033] The contour 23 is, for example, a polygon. By increasing the number of vertices of the polygon, it is possible to increase the number of unlocking positions of the device 1.

[0034] In a first embodiment illustrated in Figures 2C and 3C, the contour 23 may have the shape of a diamond. The locked position (Figure 2C) is then reached when the cam 22 pushes the locking element 5 radially by its smallest dimension, i.e., the small height of the diamond 23, and the unlocked position (Figure 3C) is reached when the cam 22 pushes the locking element 5 radially by its largest dimension, i.e., the large height of the diamond 23, until it is at its maximum.

[0035] In a second embodiment illustrated in Figure 4, the contour 23 may have a hexagonal cut surface. The unlocked position as illustrated is then reached when the cam 22 presses the locking element 5 radially with the apex of the hexagon 23.

[0036] Thus, in the first embodiment, it is necessary to rotate the input shaft 2 at least a quarter turn to unlock and rotate the output shaft 3, while in the second embodiment, rotating it by an angle of 20 degrees is sufficient.

[0037] The switching means 21 of the locking element 5 may further comprise an unlocking key 6 sandwiched between the cam 22 and the locking element 5. The key 6 is then connected in translation through a channel 31 in the output shaft 3. This has the function of pushing the locking element 5 radially out of the channel 31.

[0038] In the locked position (FIG. 2C), the key 6 is positioned between the channel 31 and the output shaft 3 and does not disengage the locking element 5 from the channel 31 .

[0039] In the unlocked position (FIG. 3C), the key is entirely housed within the channel 31, completely disengaging the locking element 5 from the channel 31. The key 6 is then allowed to rotate integrally with the output shaft 3 around the axis of the shaft, which is then allowed to rotate.

[0040] The key 6 may have a curved shape complementary to the channel 31 so that it circumscribes the channel 31 but does not protrude beyond the channel 31 and does not abut against the frame 4 in the unlocked position.

[0041] In addition, the device 1 comprises elastic return means 7 for the locking element 5 to the locking position, which act when compressed and push the locking element 5 against the cam 22 towards the axis of the shafts 2, 3.

[0042] For example, the means 7 for elastically returning to the locked position comprises a spring 71 connected to the frame 4 .

[0043] Thus, from the unlocked position (FIGS. 3C and 4), after the angular position of the output shaft 3 relative to the input shaft 2 is such that the channel 31 is aligned with the passage 41, the return means 7 presses the locking element 5 against the key 6 in the channel 31. The locked position is then engaged by the protruding positioning of the locking element 5 between the channel 31 and the passage 41, which can prevent rotation of the output shaft 3.

[0044] Thus, in the unlocked position, the device aligns the channel 31 and the passage 41 by transmitting heterokinetic rotation between the input shaft 2 and the output shaft 3, in other words a transmission driven by the output shaft rather than the drive means of the input shaft 2, thus allowing return to the locked position using the return means 7.

[0045] Thus, a no-return device is created in which rotation of the input shaft 2 unlocks the locking means 5 and transmits the rotational movement coaxially to the output shaft 3 driven by the drive means 25, 33, while rotation of the output shaft 3 does not rotate the input shaft but triggers the return of the device 1 to the locked position. [Explanation of symbols]

[0046] 1 Non-return device 2 input shaft 3 Output shaft 4 frames 5 Locking element 6 Unlocking key 7 Elastic return means 21 Radial direction switching means 22 Cam 23 Contour 24 Male end 25 Step part 31 channels 32 Female end 33 Flat area 41 Passage 71 Spring

Claims

1. A non-return device (1) for transmitting a rotary motion, comprising: Two coaxial input shafts (2) and output shafts (3); a frame (4) for guiding the rotation of the input shaft (2) and the output shaft (3); a locking element (5) radially translatable through a channel (31) of the output shaft (3) between a locked position and a radially unlocked position, in which the locking element (5) protrudes from the channel (31) to prevent rotation of the output shaft (3) and in which the locking element (5) is retracted to allow axial rotation of the output shaft (3), the input shaft (2) comprising a switching means (21) for switching the locking element between the locked position and the radially unlocked position, the switching means (21) of the locking element (5) comprises a cam (22) having a profile (23) adapted to radially move the locking element (5) upon rotation of the input shaft (2), the input shaft (2) comprises a step (25) which abuts against a flat portion (33) of the output shaft (3) to rotate the output shaft (3), and the abutment of the step (25) during rotation of the input shaft (2) is angularly coincident with the cam (22) placing the locking element (5) in the radial unlocked position; A non-return device (1) for transmitting a rotational motion, characterized in that the switching means (21) of the locking element (5) comprises an unlocking key (6) sandwiched between the cam (22) and the locking element (5), the unlocking key (6) being connected in translation through the channel (31) of the output shaft (3).

2. 2. The device of claim 1, wherein the cam (22) is provided on a male end (24) of the input shaft (2), the male end (24) being engaged with a female end (32) of the output shaft (3).

3. 3. The device according to claim 1 or 2, wherein the unlocking key (6) is fully housed within the channel (31) of the output shaft (3) in the radial unlocked position.

4. 4. A device according to any one of claims 1 to 3, comprising elastic return means (7) for the locking element (5) to the locking position, the elastic return means (7) comprising a spring (71) connected to the frame (4) and configured to work in a compressed state in order to press the locking element (5) against the cam (22) towards the axis of the input shaft (2) and the output shaft (3).

5. 5. The device according to claim 1, wherein the frame (4) has a passage (41) which coincides with the channel (31) of the output shaft in the locked position, the locking element (5) can move radially in translation through the passage (41) in the locked position, and the unlocking key (6) can move radially in translation through the channel (31) of the output shaft (3) in the locked position.

6. 6. The device according to claim 1, wherein the rotation of the output shaft (3) by the input shaft (2) and the movement to the radially unlocked position occur substantially simultaneously after the input shaft (2) has completed at least a quarter of a turn.

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