FR2759859A1 - Latch for livestock manger barrier moving bar - Google Patents

Abstract

The latch, designed to move up and down in slots in a bracket on the end of a moving bar or a manger barrier and engage with a control bar,consists of a body (2) containing a rod (2') which is threaded at least at its two ends (2a, 2b) to engage with two stops (7). The rod, which is of circular cross-section and constant thickness, has a covering layer of a shock absorbing plastic or similar material, selected from a polypropylene, polyamide or polyoxymethylene.

Description

 The invention relates to a cleat intended to be guided in translation in and along two grooves of a frame of a headlock element, the grooves being spaced apart and facing one another.

 When the headlock element is mounted, this frame is fixed to the end of a movable bar and disposed astride a substantially horizontal control bar. In addition, the grooves of the mount extend transversely to the control bar.

 The cleat of the aforementioned type is intended to be stressed by the control bar during the movements of the movable bar and to limit the movements of the movable bar.

 Knobs of the aforementioned type are known, formed of a rectilinear body, terminated at one of its ends by a grip.

 Such a cleat is in one piece and made of metal, and if necessary, entirely covered, with a plastic material which absorbs noise.

 The body of this cleat is held transversely between and in the grooves, on the one hand by the gripping end piece, and on the other hand, towards the end opposite to the gripping end piece, by blocking means passing through the body, the gripping end piece and the blocking means being arranged outside the frame.

 Furthermore, when the lock element is mounted, the body of the cleat rests on the control bar and is biased by the latter when the movable bar is moved.

 Such a cleat, however, has a number of drawbacks.

 Indeed, the gripping tip weighs a certain weight relative to the body, which unbalances the cleat when it is mounted, it cannot remain in a direction substantially perpendicular to the longitudinal direction of the grooves. This results in greater wear of the cleat body at the place which is in contact with the control bar.

 Furthermore, the drilling -or the formation of a threaded through bore- from the body of the cleat towards one of its ends, allowing the location of the blocking means - such as for example a screw - is complex to implement. , and therefore expensive.

 The invention therefore aims to overcome the drawbacks of the prior art by providing a cleat having technical characteristics allowing in particular less rapid wear thereof, easy assembly and disassembly in a corresponding frame.

 Another objective of the invention is to avoid any piercing of the body, which is relatively complex and costly.

To this end, the invention proposes a cleat of the aforementioned type, characterized in that it comprises
- a body comprising a rod, threaded at least on its end parts; and a covering formed of a damping material covering the rod, with the exception of its end portions
- Two end caps of dimensions larger than those of the body, each end piece being screwed respectively onto an end part of the rod, the end pieces having the function of keeping the cleat in the grooves when it is mounted.

 According to one embodiment of the invention, the body of the cleat has, towards at least one end part of the covering, a cross-section that is substantially in the shape of a parallelogram.

 In addition, in the central part, the body has a cross section of dimensions greater than those of the end parts, being at least the side intended to be in contact with the control bar.

 The invention also relates to a frame intended to be fixed to one end of a movable bar of a headlock element. When the latter is mounted, the frame is arranged astride a control bar, substantially horizontal.

 The frame has two grooves spaced apart and facing each other, and a cleat as mentioned above. The body of the cleat extends between and into the grooves and is guided in translation relative to the frame in and along the grooves, the end pieces holding the body in the grooves.

 According to the invention, this frame comprises two substantially parallel walls extending in the same general direction and connected together by a base wall, which is substantially perpendicular to them. Said base wall is intended to be fixed to one end of the movable bar of a headlock element, and each of the parallel walls has a groove. The ends of the cleat are also arranged outside the frame but close to the walls.

The invention also relates to a tubular structural element of a feed fence, generally extending in a main plane and comprising
- two substantially parallel beams
- at least two crosspieces substantially perpendicular to the side members and connecting them together
- a bent bar, fixed to the two beams and between the two crosspieces
- a control bar, extending substantially parallel, spaced apart but close to one of the side members
- A substantially straight movable bar, pivotally mounted on the bent bar, with its pivot axis substantially perpendicular to the main plane of the tubular structural element.

 The tubular structural element further comprises a mount of the aforementioned type, fixed, when the structural element is mounted, at one end of the movable bar, extending in the same plane as the latter, and arranged astride on said spar and the control bar, the cleat extending above the control bar.

 Finally, the invention relates to a headlock comprising at least one such element of tubular structure.

 Other features of the invention will result from the description which follows with reference to the accompanying drawings, given by way of non-limiting examples.

 Figure 1 shows a side view of a cleat according to the invention.

 2 shows, on the left side, a sectional view along the line II-II of Figure 1, and on the right side, another partial side view of the cleat devoid, on this side, of the end piece, according to the direction II ′ in FIG. 1.

 FIG. 3 represents a cross-sectional view of the cleat along the line III-III of FIG. 1.

 FIG. 4 represents a view of a tip of the cleat in the direction IV of FIG. 1.

 FIG. 5 represents a cross-sectional view along the line V-V of FIG. 4.

 FIG. 6 represents a partial perspective view of a feed fence comprising a plurality of elements of tubular structure according to different positions and embodiments.

 Figure 7 shows a view of a detail shown in VII in Figure 6, showing the cleat installed in the grooves of a frame.

 Finally, FIG. 8 represents a view of a detail shown in VIII in FIG. 6.

 With particular reference to Figures 1 and 2, the cleat 1 of the invention comprises a body 2 terminated on either side by a respective end piece 7.

 The body 2 comprises a threaded rod 2 'and a coating formed of a damping material 3.

Rod 2 'has along its longitudinal axis
L a circular cross section, substantially constant.

 It is made of a rigid material, such as for example metal.

 The covering 3 surrounds and covers - following the direction L - the rod 2 ', with the exception of the end parts 2a, 2b of said rod 2'.

 The body 2 - and more broadly the cleat 1 has a median symmetry with respect to a median transverse plane Pmt perpendicular to the longitudinal direction L of the body 2 - and therefore of the cleat 1-.

 The median plane Pm thus divides the cleat 1 into two identical halves la, lb.

 In the rest of the text, only one half of the cleat 1 will be described, the other half lb being able to deduce therefrom.

 On the half of the stopper 1, the rod 2 ′ is covered with the coating 3 over approximately 5 / 6th or 6 / 7th of its length -counted in the direction L from its free end to the plane Pm-, the part uncovered corresponding to the end part 2a of the rod.

 The coating 3 generally has a cross-section substantially in the form of a parallelogram.

 In the embodiments shown, on one half la, the covering 3 comprises two adjoining zones, an end zone 4, and a central zone 5.

 The extreme zone 4 limits, on the side opposite to the central zone 5, the extreme part 2a of the rod 2 ', while the central zone 5 envelops the central part of the rod 2'.

 The end zone 4 has in the embodiment shown a substantially rectangular cross section.

 It substantially envelops two thirds of the length of the rod 2 '-measured in the direction Ld in half the.

 In addition, the cross section of the central area 5 is substantially square.

 The faces corresponding to the long sides of the rectangular section of the end zone 4 are of dimensions substantially identical to those of the central zone, as shown in FIG. 1.

 By way of example, for a length of the order of 50 mm of the rod portion 2 ′ extending in half la, the end part 2a of the rod 2 extends over approximately 7.5 mm, while that the extreme zone 4 envelops the portion of rod over a length of approximately 32.5 mm -following the direction L- and the central zone 5 envelops the rod over approximately 10 mm.

 Furthermore, still by way of example, the diameter of the section of the rod 2 ′ is of the order of 12 mm, while the sides of the section of the central area 5 are of the order of 15 mm, and the long sides of the section of the extreme zone 4 are of the order of 18 mm.

 As shown in FIG. 2, the covering 3 comprises a notch 6, substantially inclined, forming the junction between the extreme zone 4 and the central zone 5 on the side where the adjacent faces of the extreme 4 and central 5 zones are of substantially identical dimensions.

 The angle of inclination a of this offset 6 relative to the adjacent surface of the end zone 4 is obtuse and for example between 140 and 1500.

 Of course, it could be envisaged that the end zone 4 has a substantially square cross section and that the central zone 5 has a rectangular cross section.

 In such a case, it is understood that the short sides of the rectangular section would be the same dimension as the sides of the square section of the end zone 4.

 According to other embodiments, it can be envisaged that the rod 2 'is threaded only at its end parts 2a, 2b, not covered.

 As indicated previously, the cleat 1 also comprises two substantially identical end pieces 7.

 Each end piece 7 is intended to be removably attached to an end part 2a, 2b of the rod 2 '.

 As shown in Figures 3 to 5, each end piece 7 comprises a nut 8, for example hexagonal, surrounded by a coating formed of a damping material 9, the latter being arranged so as to leave free an opening 8a of the nut 8.

 Whether for the end piece 7 or the rod 2 ′, the coating 3, 9 used is a plastic material or the like such as for example a polypropylene, a polyamide or a polyoxymethylene.

 The coating 3, 9 is disposed respectively around the rod 2 'and the nut 8 according to an injection molding process, or equivalent.

 The nut 8 is held inside the covering 9, in particular by means of two substantially rectilinear bores 10 formed in the covering 9 and opening out on the side opposite to the opening 8a, as shown in FIG. 5.

 The nut 8 has an internal section of dimension substantially complementary to that of the rod 2 '.

 The coating 9 has, on the side of the free opening 8a, a substantially planar surface 9a, of substantially circular outline.

 In addition, on the side opposite the free opening 8a, the surface 9b of the covering 9 is curved, for example, to allow better grasping.

 The cleat 1 is intended to cooperate with the grooves 11 of a mount 12.

 Referring to Figures 7 and 8, the frame 12 comprises two walls 13a, 13b substantially parallel and extending in the same general direction D.

 The parallel walls 13a, 13b are interconnected by a base wall 14 which is substantially perpendicular to them.

 Each of the walls 13a, 13b has a groove 11.

 The grooves 11 of the walls 13a, 13b are arranged opposite one another and extend in the same direction.

 In the embodiment of Figure 8, the grooves 11 extend in a direction inclined relative to the general direction D of the walls 13a, 13b.

 However, provision can be made for the grooves 11 to extend in the general direction D, as is the case in the embodiment of FIG. 7.

 In both cases, the grooves 11 are in the form of a light of substantially rectangular outline.

Each groove 11 is thus longer than wide, their length generally extending in the direction
D.

 The width of each groove 11 is slightly greater than the dimension of the end zones 4 of the body 2 of the cleat 1, so that they can be received with a slight clearance.

 A cleat 1 in the mounted position is thus adapted to be arranged transversely with respect to the two walls 13a, 13b, at least part of the end zone 4 being guided in and along the corresponding groove 11.

 It is thus understood that the parallelogram-shaped section of the coating 3, on at least one of the end zones 4, prevents the cleat 1, and more precisely its body 2, from being able to rotate in rotation on itself when it is guided in translation in the grooves 11.

 Furthermore, the end pieces 7 of the cleat 1 are fixed on the end parts 2a, 2b of the rod 2 ', so as to be close to the walls 13a, 13b but outside the frame 12, that is to say ie on the side opposite to the space delimited by the two walls 13a, 13b.

 Thus, these end pieces 7 allow the body 2 to be trapped between the grooves 11 and to be guided in translation only along the grooves 11.

 The frame 12 which has just been described, is intended to be fixed, removably or not, at one end of a movable bar of a feed fence, on the side of the base wall 14.

 Generally, a head lock has at least one tubular structural element 16, generally extending in a main plane P.

 FIG. 6 represents a headlock formed from several elements of tubular structure 16, which may be identical or different from one another, modular, in particular in size, or not.

 Generally, a tubular structural element 16 comprises two substantially parallel beams 17a, 17b, interconnected by two crosspieces 18a, 18b substantially perpendicular to said beams 17a, 17b.

 Thus, the side members 17a, 17b and crosspieces 18a, 18b define between them a space substantially in the form of a parallelogram.

 In the use position of the lock, the cross members 18a, 18b are arranged vertically, while the side members 17a, 17b are arranged horizontally.

 A bent bar 19 is rigidly fixed to the two side members 17a, 17b and between the two cross members 18a, 18b.

 More specifically, the bent bar 19 is located closer to one of the two crosspieces 18a.

 A control bar 20, movable in rotation, extends substantially parallel, spaced apart but close to the beam 17a.

 The control bar is of substantially circular cross section, as are the side members 17a, 17b, and cross members 18a, 18b.

 However, it could be envisaged to have straight cross sections substantially in the form of a parallelogram, in particular for the control bar 20.

 The control bar 20, which will be detailed below, is substantially rectilinear and tubular and has, in the embodiments shown, a diameter less than that of the beam 17a, of the order of half, for example.

 Finally, a movable bar 21, substantially rectilinear, is pivotally mounted on the bent bar 19.

 It has a length slightly less than that of the crosspieces 18a, 18b, so as to leave a free space between its free end 21b and the beam 17 when it is mounted.

 The movable bar 21 comprises towards its middle part two opposite holes, intended to come opposite the holes of a yoke 25, fixed to the elbow of the bent bar 19, to receive a pin forming the pivot axis 22 of the bar mobile 21.

 More specifically, the yoke 25 is arranged in the main plane P, and extends substantially parallel to the side members 17a, 17b and towards the crosspiece 18b.

 This yoke 25 has towards its free end two facing holes intended to receive the pin 22 passing through them in a direction substantially perpendicular to the main plane P.

 A mount 12 of the aforementioned type is fixed to the end 21a of the movable bar 21, located on the side of the beam 17a and of the control bar 20.

 As indicated above, the base wall 14 is fixed to the end 21a of the movable bar 21, for example by means of a sleeve (not shown).

 In addition, the walls 13a, 13b are arranged so as to be directed towards and surround the beam 17a and the control bar 20.

 Thus, the frame 12 is arranged "astride" the spar 17a and the control bar 20.

 I1 it is understood that the length of the base wall 14 -counted in a direction perpendicular to the direction D-, and therefore the spacing between the walls 13a and 13b, must be sufficient to receive with play the spar 17a and the bar command 20.

 Generally, the grooves 11 project beyond the control bar 20, when the movable bar 21 is substantially parallel to the crosspieces 18a and 18b.

 The stopper 1 is introduced through the grooves 11, so that it can rest on the control bar 20, and that the recesses 6 that have one face of the stopper 1 are opposite, respectively on the opposite side, from the command 20.

 The square shape of the section of the central zone 5 forms an additional thickness with respect to the end zones 4 of rectangular section and therefore a reinforcement of the coating 3, mainly on the faces - including the recesses 6- intended to be in contact with the bar command 20.

 It is understood that one could envisage reinforcing the dimension of the central zone 5 with respect to the extreme zones 4 by giving it a completely different shape, such as for example circular or oval.

 In FIG. 6, and in detail in FIG. 8, the frame 12 of the tubular structural element referenced in 16A extends in a direction inclined relative to that of the movable bar 21.

 In addition, it can be provided that, in accordance with the tubular structural element referenced in 16B, the frame 12 extends in the same direction as the movable bar 21 (Figure 7).

 In both cases, the grooves 11 are arranged so as to extend in the same direction as the movable bar 21.

 Thus, in the case of the structural element 16A, the grooves 11 extend longitudinally in a direction inclined relative to the direction D of the walls 13a, 13b.

 In addition, for the tubular structural element 16B, the grooves 11 extend longitudinally in the same direction D as that of the walls 13a, 13b.

 The tubular structural elements 16A and 16B also have differences in terms of the shape and function of the bent bar 19.

 Indeed, for the tubular structural element 16A, the bent bar 19 is formed of a first rectilinear section 19a, close to and parallel to one of the crosspieces 18a and of a second rectilinear section 19c, parallel to the first l9a, and offset, in the main plane P, relative to the first section 19a towards the other crosspiece 18b.

 These two sections 19a, 19c are connected to each other by a third inclined section 19b.

 The elbow l9d on which the pivot axis 22 of the movable bar 21 is mounted, is located at the intersection of the sections 19b and l9c.

 Thus, the movable bar 21 can be in two positions: a closed position, as shown, where it is substantially parallel to the two crosspieces 18a, 18b and an open position, not shown, where it is inclined relative to the crosspieces 18a, 18b and substantially parallel to the third inclined section 19b.

 The closed position does not allow the passage of the head of a beast, while the open position allows the passage of the beast.

 In addition, to condemn the passage of a beast between in particular the section 19c and the crosspiece 18a, a blocking amount 23, substantially rectilinear, extends between the latter, in a direction substantially parallel to that of the crosspiece 18a.

 Passage locking means 24 can also be provided between the end 21a of the movable bar 21 and its pivot axis 22.

These locking means 24 extend in a plane offset, but parallel, relative to the main plane
P, between the movable bar 21 and the bent bar 19.

 They are in the form of a curved tube, the two ends 24a, 24b of which are rigidly fixed to the movable bar 21.

 Of course, other forms can be envisaged.

 The size of these locking means 24 is such that they occupy substantially half of the space separating the section 19a and the movable bar 21, when the latter is substantially parallel to the crosspieces 18a, 18b.

 In the embodiment of the tubular structure element shown in 16B, the bent bar 19 is tubular and in one piece - as is the case for the bent bar 19 of the tubular structure element referenced in 16A - but has a different shape.

 Indeed, the bent bar 19 is formed, in one piece, of two tubular sections l9a ', 19c' substantially aligned and parallel to the crosspieces 18a, 18b, and of a bent tubular portion l9b ', connecting the two sections 19a ', 19c' between them.

 The bent tubular portion 19b ′ comprises two rectilinear segments S1, S2, inclined with respect to each other by an angle of approximately 900 and the point of convergence of which forms the elbow l9d, on which the axis is mounted pivot 22 of the movable bar 21.

 The segment S1, located towards the beam 17a, has a length slightly greater than that of the segment S2, while the sections 19a ', 19c' have a substantially identical length.

 Their dimension is such that the elbow 19d is located towards the middle part of the bent bar 19, in the lower part of the structural element 16B, that is to say the part comprising the lower spar 17b.

 The free ends of the sections 19a ′, 19b ′ are fixed respectively to the upper beam 17a and to the lower beam 17b near the crosspiece 18a, the elbow 19d being directed towards the crosspiece 18b.

 The bent bar 19 is produced by twisting a straight bar. Consequently, the connections between the sections 19a ′, 19c ′ and the bent portion 19b ′, and the elbow 19d are rounded.

The movable bar 21 can thus be arranged in three positions
- A closed position, shown for the element 16B (Figure 6), where it is substantially parallel to the two crosspieces 18a, 18b, the animal can not pass its head between the movable bar 21 and the crosspiece 18b;
- An open position, shown for the element 16C, where it is inclined relative to the crosspieces 18a, 18b, with the mount 12 close to the bent bar 19, the beast being able to pass its head in the upper part of the element of locks 16C between the movable bar 21 and the crosspiece 18b
- A release position, shown for the element 16D, where it is inclined, with the mount 12 towards the crosspiece 18b, this position allowing to release the head of the beast when it is wedged in the lower part of the element of headlock 16D, between the movable bar 21 and the crossbar 18b.

 In the present embodiment, the movable bar 21 comprises locking means 24, similar to those of the structural element 16A.

 It is possible to envisage fixing two of them, one being placed between the mount 12 and the pivot axis 22, the other being placed between the free end 21b of the movable bar 21 and the pivot axis 22.

 It is also possible to envisage fixing only one, for example in the lower part, as is the case for the structural element 16C or 16D.

 In the embodiment of the tubular structural element shown in 16B, the control bar 20 comprises a pair of projections 26a, 26b (see FIG. 7).

 Each projection 26a, 26b is formed by a ramp 27a, 27b and a locking edge 28a, 28b.

 The ramps 27a, 27b are inclined at an angle of about 100 relative to the general direction of the control bar 20 and are terminated at their top by the locking edge 28a, 28b which is perpendicular to the control bar 20 .

 The projections 26a and 26b are arranged so that the edges 28a and 28b are opposite and separated from each other by a space adapted to receive with a slight play the stopper 1, and more precisely its central zone 5.

 The control bar 20 also includes a projection 29, similar in shape to that of the projections 26a and 26b, diametrically opposite the pair of projections 26a, 26b.

 The projection 29 is arranged so that its ramp 29a faces the ramp 27b of the projection 26b and that its locking edge 29b is aligned with the locking edge 28b of the projection 26b, in the direction of the crosspieces 18a, 18b , so that the base of the ramp 29a is directed towards the crosspiece 18a (see Figure 7).

 Thus, depending on the angular position of the control bar 20, the cleat 1 can be urged by one of the projections 26a, 26b to be locked between the locking edges 28a, 28b or by the projection 29 to be locked against the edge blocking 29b.

 Furthermore, the movement from one position to the other of the movable bar 21 is limited by the end 11a of the grooves 11, situated on the side opposite to the base wall 14.

 It will thus be understood that the grooves 11 must have a sufficient length so that the cleat 1 can be guided therein until it comes into abutment against its end 11a, when the movable bar 21 is in the open and release position.

 Thus, when the angular position of the control bar 20 is such that the cleat 1 is blocked between the locking edges 28a and 28b of the projections 26a and 26b, the movable bar 21 is blocked in the closed position, that is to say -display is substantially parallel to the crosspieces 18a and 18b (as shown in Figure 6 for the tubular structural element 16B).

 If, from this position, the control bar 20 is turned a quarter of a turn, the cleat 1 is not biased by any projection.

 The movable bar 10 can thus take any closed, open or release position, since the cleat 1 is free to move.

 The rotation of the control bar 20 by another quarter of a turn, from this latter position, in the same direction as previously, causes the cleat 1 to block against the blocking edge 29b.

 The movable bar 10 can thus pass freely from the closed position to the open position shown for the tubular structure element referenced in 16C.

 In the embodiment of the tubular structural element 16A, the control bar 20 has only one projection, similar to the projection 29 defined above.

 This projection 29 thus makes it possible to block the movable bar 21 in the closed position only.

 It is understood that the length of the grooves 11, and therefore that of the walls 13a, 13b of the mount 12, must be sufficient for the cleat 1 to be able to overcome the projections 26a, 26b and / or 29.

 In the embodiments which have just been described, it is possible to provide means for blocking and locking 30 of the control bar 20 in one of its angular positions, as well as means for spacing 31 of the control bar 20 relative to the beam 17a.

 Of course, the invention is not limited to the embodiments which have just been described.

 One can for example consider using intermediate means fixed to the cleat 1 and cooperating with at least one projection 26a, 26b or 29.

Claims (21)

 1. Cleat (1) intended to be guided in translation in and along two grooves of a frame of a headlock element, the grooves being spaced apart and facing one another; when the headlock element is mounted, said frame being fixed to one end of a movable bar and disposed astride a control bar, substantially horizontal, the grooves extending transversely relative to the control bar; the cleat being intended to be stressed by the control bar during movements of the movable bar and to limit the movements of the movable bar, characterized in that it comprises  - a body (2) comprising a rod (2 '), threaded at least on its end parts (2a, 2b); and a covering (3) formed of a damping material covering the rod (2 '), with the exception of its end parts (2a, 2b)  - two end pieces (7) of dimensions greater than those of the body (2), each end piece (7) being screwed respectively on an end part (2a, 2b) of the rod, the end pieces (7) having the function of maintaining the cleat in the grooves when mounted.  2. Cleat according to claim 1, characterized in that the rod (2 ') has a constant section along its axis.  3. Cleat according to claim 1, characterized in that the rod (2 ') has a substantially circular cross section.  4. Cleat according to one of claims 1 to 3, characterized in that the body (2) has, towards at least one end portion (4) of the covering (3), a cross section substantially in the form of a parallelogram.  5. Cleat according to one of claims 1 to 4, characterized in that the body (2) has in the central part (5) a cross section of dimensions greater than those of the end parts, being at least the side intended for be in contact with the control bar (20).  6. Cleat according to one of claims 1 to 5, characterized in that each end piece (7) comprises a nut surrounded by a coating of damping material (9).  7. Cleat according to one of claims 1 to 6, characterized in that the coating of damping material (3, 9) is made of plastic or the like.  8. Cleat according to claim 7, characterized in that the coating of damping material (3, 9) is chosen from polypropylene, polyamide, polyoxymethylene.  9. Frame (12) intended to be fixed to one end of a movable bar of a headlock element when the latter is mounted, the frame being arranged astride a control bar (20), substantially horizontal; the frame comprising two grooves (11) spaced apart and facing each other, characterized in that it comprises a cleat (1) according to one of claims 1 to 8, the body (2) of which extends between and into the grooves (11) and is guided in translation relative to the frame (12) in and along the grooves (11); the ends (7) of the cleat (1) holding the body (2) in the grooves (11).  10. Frame according to claim 9, characterized in that it comprises two substantially parallel walls (13a, 13b) extending in the same general direction (D) and connected together by a base wall (14), which their is substantially perpendicular, said base wall (14) being intended to be fixed to one end of the movable bar of a headlock element; each of the parallel walls (13a, 13b) having a groove (11), the end pieces (7) of the cleat (1) being arranged outside the frame (12) but close to the walls (13a, 13b).  11. Frame according to one of claims 9 or 10, characterized in that the grooves (11) extend in the same direction.  12. Frame according to one of claims 9 to 11, characterized in that the grooves (11) extend in the general direction (D) of the walls (13a, 13b).  13. Frame according to one of claims 9 to 11, characterized in that the grooves (11) extend in an inclined direction relative to the general direction (D) of the walls (13a, 13b).  14. Element of tubular structure (16) of a feed fence, generally extending in a main plane (P) and comprising  - two substantially parallel beams (17a, 17b)  - at least two sleepers (18a, 18b) substantially perpendicular to the side members and connecting them together  - a bent bar (19), fixed to the two beams (17a, 17b) and between the two crosspieces (18a, 18b)  - a control bar (20), extending substantially parallel, spaced apart but close to one of the side members (17a)  - a movable bar (21) substantially rectilinear, pivotally mounted on the bent bar (19), with its pivot axis (22) substantially perpendicular to the main plane (P) of the tubular structural element (16)  characterized in that it further comprises a mount (12) according to one of claims 9 to 13, fixed, when the structural element is mounted, at one end (21a) of the movable bar (21), s 'extending in the same plane as the latter, and disposed astride said spar (17a) and the control bar (20), the cleat (1) extending above the control bar (20).  15. Element of tubular structure according to claim 14, characterized in that the frame (12) extends substantially in the same direction as the movable bar (21).  16. A tubular structural element according to claim 14, characterized in that the frame (12) extends in a direction inclined relative to that of the movable bar (21).  17. Element of tubular structure according to one of claims 14 to 16, characterized in that the grooves (11) extend in the same direction as the movable bar (21).  18. A tubular structural element according to one of claims 14 to 17, characterized in that the control bar (20) is movable in rotation and comprises at least one projection (29), formed by a ramp (29a) and a locking edge (29b), terminating the ramp and substantially perpendicular to the control bar (20), the ramp being intended to urge the cleat (1), and the blocking edge to block the cleat (1), when the headlock is in the operating position and according to the angular position of the control bar (20).  19. Structural element according to claim 18, characterized in that the control bar (20) comprises a pair of aligned projections (26a, 26b), of shape substantially identical to that of said projection (29), with their edge respective blocking (28a, 28b) facing and separated from each other by a space adapted to receive the cleat (1) to block it.  20. Structural element according to claim 19, characterized in that the pair of projections (26a, 26b) is diametrically opposite to said projection and the locking edge (28b) of one of the projections (26b) of the pair of projections (29) is aligned with the locking edge (29b) of said projection (29).  21. Head locks characterized in that it comprises at least one tubular structural element (16) according to one of claims 14 to 20.