FR2545171A1 - Improvements made to protection devices covering universal joint transmission shafts - Google Patents

Abstract

The present invention relates to improvements made to protection devices covering the universal joint transmission shafts. It relates to at least a first reinforcing ring 9, which is force fitted on the transmission shaft 1 with functional clearance with respect to the tubes 4 and 5 of the protection device 6, and to a second reinforcing ring 10 which is introduced by force inside each cone 8 of the said protection device 6. This second reinforcing ring 10 and at least the said first reinforcing ring 9, which are made from a material which is resistant to variable extreme temperatures, allow transverse loads to be absorbed and prevent the cones 8 and the tubes 4 and 5 from coming into contact with the shaft 1. Application: protection of universal joint transmission shafts intended for agricultural uses.

Description

 The present invention relates to improvements made to the protective devices covering the cardan drive shafts, in particular the telescopic drive shafts which are intended to connect an agricultural tool or machine to the end of a power take-off. , including a tractor.

 The existing protective devices, for telescopic driveshafts, consist of two tubes, in particular cylindrical and of plastic material, also telesoupi cs, which overlap, while the metal tubes of telescopic driveshafts have a section a priori g.uelconque, except circulating, so that the driving tube can cooperate with the driven tube: in practice are widely used tXlescopic tubes with square (or rectangular) or ovoid section.

 At each end of the cylindrical protection tubes are mounted a flexible ring with hooking claws, tightened on the groove of the transmission, and, externally to this ring, a cone of overlap of the universal joint, each end of the azi > re de transmissicn is provided to connect the latter to the power take-off, in particular of a tractor, and to the implement, or to the agricultural machine, driven by this power take-off; the aforementioned claw ring and the covering cone are both made of plastic.

 However, the protection devices of the prior art have a certain number of drawbacks, which have been highlighted during tests carried out at the CEMAGREF test center (National Center for Agricultural Engineering of Rural Water Engineering and Forests), in particular - with regard to the application of transverse loads on the tubes of the protection device, perpendicular to the rotating drive shaft; high speed, in particular at a speed of the order of 1000 revolutions / minute and more under the action of these loads, the protective tubes deteriorate, even pierce or weld together, because they come into contact with the shaft transmission - with regard to the application of transverse loads on the cones of the protection device, perpendicular to 11 transmission shaft rotating at high speed, r: otalt'aent at a speed of the order of 1000 revolutions / minute and more: under the action of these loads the protective cones also deteriorate because they come into contact with the universal joints - as regards the application of axial loads, in particular of traction, applied either to the cones or to the tubes of the protection device: under the action of these loads, the rings with hooking claws come out of their grooves thus revealing the cardan drive shaft, this qdi becomes dangerous under normal working conditions; - with regard to the application of shocks to the tubes and cones protection device1 under operating conditions, bare at low temperature: these tubes and these connectors break under the action of shocks making the protection device totally unusable - in this as regards the lubrication of moving parts, no means have been provided for this purpose, which consequently causes abnormal wear of these parts, which are used in an environment polluted with particularly abrasive particles, such as agricultural environment.

 The present invention therefore aims to provide devices for protecting cardan shafts, in particular for agricultural use, which better meet the needs of practice than the devices for the same purpose previously known, in particular - in that 'they have a high resistance to transverse loads - in that they have a high resistance to axial loads - in that they make it possible to easily carry out disassembly and interchangeability operations; - in that they have a high resistance to cold shock, and - in that they allow the lubrication of moving parts.

 The subject of the present invention is a protective device made of plastic covering the cardan drive shafts, in particular the telescopic drive shafts intended for agricultural uses and constituted by two metal tubes, of a priori any section but such as the tube metallic driver can cooperate with the driven metallic tube, in particular with square or ovoid section, said metallic tubes being able to slide one inside the other to give an elongation of variable length depending on the machine, in particular agricultural, entralée by a grip force, in particular a tractor, which protection device comprises two telescopic tubes, in particular cylindrical and made of plastic, which overlap and which surround the transmission shaft, a flexible ring with hooking claws being mounted on the groove of the transmission at each end of these cylindrical protection tubes, as well as, outside said ba gue, a cone for covering the universal joint with which each end of the propeller shaft is provided, which protective device is characterized in that at least one first reinforcing ring, made of plastic resistant to extreme temperatures ;; es variables, is force fitted on the transmission shaft with a functional clearance with respect to the tubes of the protection device, to absorb the transverse loads applied to said protection tubes perpendicular to the transmission shaft and to prevent these protective tubes come into contact with the transmission shaft under the action of said transverse loads, and in that a second reinforcing ring, also made of material resistant to extreme variable temperatures, is also force-fitted inside each cone of the protective device to give it the rigidity necessary to absorb the transverse loads applied to the cones of prote ction perpen dicular to the drive shaft and to crncher that these cones come into contact with the universal joints 7 the the first reinforcement ring and each second reinforcement ring being secured to the drive shaft and with each cone, respectively, by any appropriate means.

According to an avalltagoxax embodiment of the protection device according to the invention, the first reinforcing ring, which has a section whose inner periphery adapts to the section of the largest of the telescopic tubes of the transmission shaft, in particular square or ovoid, while its outer periphery adapts to the section, in particular circular, of the smallest of the protective tubes, also has a structure lightened by hollow spaces formed uniformly in the mass of said first reinforcing ring, so such that the latter retains its rigidity, the sliding of said first reinforcing ring along the transmission shaft being prevented by the provision of stops on the transmission shaft on either side of this first rendering ring
According to another advantageous embodiment of the protection device according to the invention, the second reinforcing ring is in the form of a flat ring secured to each protection cone using a plurality of fixing lugs which project from the outer surface of this ring perpendicular to the latter in the plane of this second reinforcing ring, and which are placed inside housings specially provided for this purpose in each protective cone.

 According to a preferred arrangement of this embodiment, the second reinforcement ring is provided with four fixing lugs at 900 one with respect to the other and each lug is produced in the form of a non-return hook to prevent this second reinforcement ring comes out of its housing.

 According to yet another advantageous embodiment of the protective device according to the invention, a clamp, also made of material resistant to extreme variable temperatures, is fitted onto said flexible ring with hooking claws, which collar comprises a substantially planar ring which has a notch and two projections which project from the outer surface of the clamp on either side of this notch and substantially parallel to the longitudinal axis of the latter, a slot substantially in the form of an arc of circle being formed centrally in each projection, the portions of each projection defined by said circular slot and comprised between the latter and the notch being enveloped by a circular cam which is provided with an oval central slot and which makes it possible to carry out the tightening of said collar on the ring with hooking claws, to prevent any flexibility thereof and to absorb the es axial loads has in particular traction, applied either on the cones or on the tubes of the protection device, as well as to allow the opening of said clamp leaving flexibility to the ring with hooking claws and, by then disassembly of the protection device.

 According to a preferred arrangement of this embodiment, the tightening and opening operations of the ring with hooking claws are made rapid using a diametrical groove formed frontally in the cam, which can thus be actuated. by means of any flat rod of appropriate thickness, in particular using a simple screwdriver, an access opening to the cam being specially provided for this purpose in each protective cone in the appropriate position, which allows easily carry out disassembly and interchangeability operations.

 According to an advantageous embodiment of the protective device according to the invention, a lubrication orifice is provided in the tubes of the protective device in exact correspondence with the location of at least said first reinforcing ring, this orifice being norrr, alt obstructed by a removable plastic plug.

 According to another advantageous embodiment of the protection device according to the invention, a greasing nipple is provided on the flexible ring with hooking claws to grease the groove of the transmission, an orifice being provided for this purpose in the collar tightening of this penal colony with hooking claws as well as in the protective cone, the orifice which is formed in the latter being normally also blocked by a removable plastic plug.

 According to yet another advantageous embodiment of the protection device according to the invention, at least said first reinforcing ring, as well as each second reinforcing ring and each clamp, which are resistant to extremely variable temperatures, are made of plastic material, in particular polyamide filled with glass fibers.

 According to another embodiment of the protective device according to the invention, also the tubes and the cones of the protective device are made of a plastic material resistant to extreme variable temperatures, in particular EsPoDoMe (ethylene, propylene, diene , monomer), to resist cold shock.

 In addition to the foregoing provisions, the invention also comprises other provisions, which will emerge from the description which follows.

The invention will be better understood with the aid of the additional description which follows, which refers to the appended drawings in which: FIG. 1 is an axial longitudinal section of a telescopic transmission shaft, covered with a protection device, showing the reinforcement rings and the lock collar according to the invention - Figure 2 is a cross section along line II of the drive shaft shown in Figure 1 and shows in section the first reinforcement sleeve fitted on the tube metallic exterior of the telescopic drive shaft, which is in particular a square faction - Figure 3 is another cross section, along III, of the drive shaft shown in Figure 1, showing in section the second reinforcement ring introduced into the protective cone - Figure 4 is yet another cross section, according to
IV, of the transmission shaft shown in the figure to show in section the clamp according to the invention in cooperation with a cam ensuring the tightening and the rapid opening of this clamp - FIG. 5 is a cross section, along V, of the clamp shown in Figure 4.

 It should be understood, however, that these drawings and the corresponding descriptive parts, are given solely by way of illustration of the subject of the invention, of which they do not in any way constitute a limitation.

 The transmission shaft 1 represented in FIGS. 1 and 2 is a telescopic universal joint transmission shaft intended for agricultural use, constituted by two metal tubes 2 and 3 which, by sliding one inside the other, can give an extension of length. variable depending on the machine, especially agricultural, driven by a PTO, especially a tractor.

 These two metal tubes 2 and 3 have a square section, which allows the driving tube 2 to cooperate with the driven tube 3: however, it is obvious that this section can be any priori (except circular, of course), for example ovoid. Or other.

 FIGS. 1 and 2 also show the two tubes 4 and 5, in particular cylindrical and made of plastic, also telescopic, of the protection device 6 covering the cardan drive shaft 1.

 In FIGS. 1 and 4 is also shown the flexible ring with claws dQaccrochage 7 which is mounted on the groove of the universal joint transmission, as well as the protective cone 8 (cf. also FIG. 3) which covers each universal joint each end end of the drive shaft 1 is provided for connecting the latter to the power take-off and to the agricultural machine driven by the latter.

 The first reinforcing ring 9 in accordance with the invention, shown in FIGS. 1 and 2, is force fitted onto the transmission shaft 1, with a functional clearance relative to the protection tubes 4 and 5, to absorb the loads. transverse applied to said protection tubes 4 and 5 perpendicular to the transmission shaft 1 and to prevent these tubes 4 and 5 coming into contact with this transmission shaft l under the action of transverse loads.

 This first reinforcing ring 9 is advantageously made of all materials resistant to said transverse loads, as well as to variable extreme temperatures, in particular plastic, in particular polyamide loaded with glass fibers.

 The sliding of the reinforcing ring 9 along the transmission shaft i is prevented by the provision of stops on this shaft I, on either side of this first reinforcing ring 9, in particular by a welding point.

 To lighten the first reinforcing ring 9, hollow spaces 9a are formed uniformly in the mass of the ring 9, so as to keep the latter all its rigidity.

 The inner periphery of the first reinforcement tank 9 (cf. FIG. 2) adapts to the square periphery of the metal tube 2 of the transmission shaft 1, this adaptation having to be respected also in the case of the tubes of the shaft transmission 1 are of different section, in particular ovoid or other.

 Advantageously, it is possible to use a plurality of reinforcement tanks of the type of tank 9 arranged on the transmission shaft l, so as to prevent the tubes 4 and 5 of the protection device 6 coming into contact with the shaft of transmission 1 for any transverse load whatsoever applied to any point whatsoever of the protection tubes 4 and 5.

 The second reinforcing ring 10 according to the invention, shown in FIGS. 1 and 4, is forced into the interior of each cone 8 of the protection device 6 to give it the rigidity necessary to absorb the loads. transverse applied to the protective cones 8 perpendicular to the drive shaft 1, and to prevent these cones 8 coming into contact with the universal joints.

 This second reinforcing ring 10 is in the form of a flat ring, also made of all materials resistant to variable extreme temperatures, in particular in polyamide loaded with glass fibers as already indicated on the subject of the first reinforcing ring 9. This ring 10 is secured to the protective cone 8 using a plurality of fixing lugs 11, produced in the form of non-return hooks, which protrude from the external surface of this ring 10 perpendicularly to this in the plane of this second reinforcement ring 10.

 In each protective cone 8 have been provided housings 11a for receiving the fixing lugs 11 in the example of: production, not imitative, of the second reinforcement ring 10 (cf. FIG. 3), four lugs have been provided on the periphery of the ring 10, the angular spacing of one with respect to the other being 900.

 Figures 1, 4 and 5 refer to the clamp 12 quick opening according to the invention.

 This clamp 12, also made of all materials resistant to variable extreme temperatures, in particular polyamide loaded with glass fibers, is fitted onto the ring with hooking claws 7.

 Said clamp 12 includes a substantially planar ring which has a V-shaped notch 13 and two projections 14 and 15 which project from the outer surface of this clamp 12, on either side of this notch 13 and parallel to the longitudinal axis of the latter.

 In each projection 14 and 15 is provided centrally a slot 16 substantially in the form of an arc of a circle the portions 14a and 15a of each projection 14 and 15 defined by said circular slot 16 and included between the latter and the notch 13 are enveloped by a circular cam 17 which is provided with an oval central slot 18.

 Thanks to this cam 17 and its oval central slot 18, it is possible to easily tighten the collar 12 on the ring with hooking claws 7 in order to prevent any flexibility thereof and to absorb the axial loads, in particular of traction, applied either on the cones 8 or on the tubes 4 and 5 of the protection device 6.

 This cam 17 also allows the opening of said clamp 12, leaving all flexibility to said ring with hooking claws 7, and therefore the disassembly of the protection device 6.

 In the cam 17 is formed frontally and diametrally a groove 19 which makes fast the operations of tightening and opening of the ring with hooking claws 7, in particular using any flat rod of thickness suitable, including a simple screwdriver; 11 access to this groove 19 is made possible by means of an opening 20 made in an appropriate position in each protective cone 8: in this way the disassembly and interchangeability operations can be carried out easily.

 To make possible the lubrication operations of the moving parts, in the tubes 4 and 5 of the protection device 6, a lubrication orifice (not shown) is formed in exact correspondence with the location of at least said first reinforcing ring 9, this orifice being normally obstructed by a removable plastic plug. In addition, a grease nipple 21 is provided on the ring with hooking claws 7 for greasing the groove of the transmission.

 To access the lubrication nipple 21, two orifices 22 and 23 are provided, the orifice 22 of which is formed in the clamp 12, - while the orifice 23 is formed in the protective cone 8, this last Zen opening 23 being normally also obstructed by a removable plug 24 made of plastic.

 To withstand cold shocks, not only the reinforcing rings 9 and 10 and the clamping collar 12 are made of all materials resistant to variable temperatures, but also the tubes 4 and 5 and the cones 8 of the protection 6, these tubes 4 and 5, as well as these cones 8, also being made of plastic, in particular EPDM (ethylene, propylene, diene, monomer).

 In this way, in cooperation with said reinforcing rings 9 and 10 and said clamp 12, in accordance with the invention, the protection devices for drive shafts have a high resistance to transverse and axial loads, as well as to shocks in the cold, while ensuring rapid interchangeability.

 As is apparent from the above, the invention is in no way limited to those of its embodiments and of application which have just been described in a more exDlìcite manner; on the contrary, it embraces all the variants which may come to mind of the technician in the matter, without departing from the framework, or the scope, of the present invention.

Claims (1)

 1 - Protective plastic device covering the cardan drive shafts F in particular the telescopic drive shafts intended for agricultural uses and constituted by two metal tubes with a priori any section but such that the metallic drive tube can cooperate with the driven metal tube, in particular with a square or ovoid cross section, said metal tubes being able to slide one inside the other to give an elongation of variable length depending on the machine, in particular agricultural, driven by a power take-off, in particular a tractor , which protection device comprises two telescopic tubes, in particular cylindrical plastic frt, which overlap and which surround the transmission shaft, a flexible ring with hooking claws being mounted on the transmission groove at each end of these cylindrical tubes same protection, outside of said ring, a joint cone gimbal with which each end of the transmission shaft is provided, which protection device is characterized in that at least one first reinforcing ring (9), made of material resistant to variable extreme temperatures, is force fitted on the shaft transmission (1) with a functional clearance with respect to the tubes (4 and 5) of the protection device (6), to absorb the transverse loads applied to said protection tubes (4 and 5) perpendicular to the transmission shaft (1 ) and to prevent these protective tubes (4 and 5) coming into contact with the drive shaft (1) under the action of said transverse loads, and in that a second reinforcing ring (10), too made of material resistant to variable extreme temperatures is also forcefully inserted inside each cone (8) of the protection device (6) to give it the rigidity necessary to absorb the transverse loads applied to the cones of protection (8) perpendicular to the drive shaft (1) and to prevent these cones (8) coming into contact with the universal joints, the first reinforcement ring (9) and each second reinforcement ring (10) being secured with the drive shaft (1) and with each cone (8), respectively, by any suitable means.  20 Protective device according to claim 1, characterized in that the first reinforcing ring (9), which has a section whose inner periphery is adapted to the section of the largest of the telescopic tubes (2) of the drive shaft ( 1) in particular square or ovoidea while its outer periphery adapts to the section, in particular circular, at the smallest of the protective tubes (4) also has a structure lightened by hollow spaces (9a) formed uniformly in the mass of said first reinforcing ring (9), so that the latter retains its rigidity, the sliding of said first reinforcing ring (9) along the drive shaft (1) being prevented by the provision of stops on the transirission shaft (1) on either side of this first reinforcement ring (9).  40- Protective device according to claim 3, characterized in that the second reinforcing ring (10) is provided with four fixing studs (11) at 900 relative to each other and each lug (it) is produced in the form of a non-return hook to prevent this second reinforcement ring (10) from coming out of its housing (11a).  30- Protective device according to claim 1, characterized in that the second reinforcing ring (10) is in the form of a flat ring secured to each protective cone (8) using a plurality of lugs fixing (it) which protrude from the outer surface of this ring (10) perpendicular thereto, in the plane of this second reinforcing ring (10), and which come to be placed inside the housings (lia ) specially designed for this purpose in each protective cone (8)  in that the tightening and opening operations of the hooking claw ring (7) are made rapid by means of a diametrical groove (19) formed frontally in the cam (17), which can thus be actuated by means of a flat rod which conch, of appropriate thickness, in particular using a simple screwdriver, an opening (20) for access to the cam (17) being specially provided for this purpose in each cone protection (8) in the appropriate position, which allows easy disassembly and interchangeability.  6 - Device according to claim 5, characterized  (13) being enveloped by a circular cam (17) which is provided with an oval central slot (18) and which makes it possible to clamp said cellar (12) on the ring with hooking claws (7), to prevent any flexibility to the latter and to absorb the axial loads, in particular traction, applied either on the cones (8) or on the tubes (4 and / or 5) of the protection device (6), as well as to allow the opening of said clamping collar (12), leaving all flexibility to the ring with hooking claws (7) and, by following and dismantling the protection device 66)  50- Protective device according to claim 1, characterized in that a clamping collar (12), also made of material resistant to extreme variable temperatures a is fitted onto said flexible ring with hooking claws (7) which collar ( 12) includes a substantially planar ring which has a notch (13) and two projections (14 and 15) which project from the external surface of the clamp (12) on either side of this notch (13) and substantially parallel to the longitudinal axis of the latter, a slot (16) substantially in the form of an arc of a circle being provided centrally in each projection 14 and 15, the portions (14a and lSa) of each projection (14 and 15 respectively) defined by said circular slot (16) and included between the latter and the notch  (24) made of plastic.  go- Protective device according to claim 1, characterized in that a greasing stud (21) is provided on the flexible ring with hooking claws (7) for greasing the groove of the transmission, an orifice (22 and 23 ) being formed for this purpose in the clamping collar (12) of this ring with hooking claws (7) as well as in the protective cone (8) the orifice (23) which is formed in the latter, being normally also obstructed by a loose plug  7c protective device according to claim 1, characterized in that a lubrication orifice is formed in the tubes (4 and 5) of the protective device (6) in exact correspondence with the location of at least said first ring of reinforcement (9) this orifice being normally blocked by a removable plastic plug  9 - Protection device according to claims 1 to 5, characterized in that at least said first reinforcing ring (9), as well as each second reinforcing ring (10) and each clamp (12), which are resistant at extreme variable temperatures, are made of plastic, in particular of polyamide loaded with glass fibers.  10 - Protection device according to claim 1, characterized in that q: u 'also the tubes (4 and 5) and the cones (8) of the protection device (6), are made of a plastic material resistant to extreme temperatures variable, especially in EPDM (ethylene, propylene, diene, monomer) to resist cold shock.