The invention relates to a device for converting a rotation movement into a translation movement of two members which are guided translatably relative to each other or vice versa. A known device of this type is a gear rack device. When the stroke of the translation movement is comparatively large relative to the dimensions of the member for displacing and the rack is accordingly relatively long, the rack will extend outside the periphery of the displaceable member in at least one of the end positions. In particular applications this forms an obstacle, for instance because a passage is blocked.

With the device according to the invention this drawback is obviated. The elongate element such as a rack is takes a curved and pivotable form according to the invention. This element can hereby swivel away during the translation movement and thus remain within the periphery of the displaceable member.

The invention also relates to and provides a displaceable feeding fence which comprises a frame which is movably guided over a floor and which supports a feeding fence in which a plurality of openings are defined for passage of the head of an animal. The drive device for displacing the feeding fence therein comprises a device of the said type wherein the rotatable engaging wheel is arranged on the displaceable fence itself and the pivotable element with the curved engaging surface is hingedly connected to the floor.

This drive device can thereby be embodied such that in the wholly retracted position of the feeding fence the pivotable element is for instance swivelled upward so that the space in front of the feeding fence is not obstructed by protruding parts of the drive device.

During the gradual forward movement of the feeding fence the pivotable element swivels downward, but can therein remain within the transverse dimension of the feeding fence, so that also in the moved forward position the pivotable element does not obstruct the free passage in front of the feeding fence.

An identical drive device is preferably used on either side of the feeding fence, wherein the engaging wheels are mutually coupled, so that the feeding fence is urged to move parallel to itself. Suitable embodiments are characterized in the remaining claims.

The invention will be further elucidated in the following description with reference to the embodiments shown in the figures.

Figure 1 shows a partly broken away perspective view of a feeding fence according to the invention; figure 2 shows a partly broken away side view of the feeding fence of figure 1, wherein three displacement positions are shown in order to elucidate the operation of the drive device; figure 3 shows an alternative drive device; figure 4 shows a partly schematic perspective detail view of the device of figure 3; figure 5 shows yet another embodiment of the drive device; figure 6 shows yet another embodiment; figures 7-10 show a feeding fence corresponding with figure 1 as according to a further developed embodiment of the invention.

Figure 11 shows a partly broken away perspective side view of another embodiment variant. Figure 12 shows a view according to arrow XII in figure 11.

Figure 13 is a view corresponding with figure 12 on a larger scale, wherein the different components are named.

The displaceable feeding fence shown in figure 1 comprises a frame 2 which supports a feeding fence 3 in which a plurality of openings 4 is defined for passage of the head of an animal. During use feed which the cattle can reach via the openings 4 is heaped on the front side of the feeding fence, i.e. on the left-hand side in figure 1.

In figure 1 is shown that the actual feeding fence is of the self-catching type, having catching bars arranged at the position of each opening 4, which bars are drawn in closed position in figure 1.

The entire feeding fence 1 is displaceable parallel to itself over the floor 7 in that it supports in this embodiment on slide blocks 5. A rubber mat 6 is connected with one end to a rear edge of the frame 2 and with its other end to the floor 7. The mat rolls out over the floor surface 7 when the feeding fence 1 is displaced forward out of the rearmost position shown in figure 1. The mat 6 therein covers the floor so that it is not fouled by manure. For displacement of the feeding fence 1 is arranged a drive device 10 comprising two identical transmissions on either end of the frame 2.

These transmissions are devices according to the invention for converting a rotation movement into a translation movement of two members which are guided translatably relative to each other or vice versa, wherein in this case the two members are formed by the feeding fence 1 and the floor 7.

This device comprises a rotatable engaging wheel in the form of a pinion 12 mounted on frame 2 of feeding fence l. This pinion 12 co-acts with a pivotable element in the form of a rack 11 which has an engaging surface 20 in the form of a rack toothing which is in driving

engagement with pinion 12. The engaging surface 20 extends in accordance with a curved line between two points of the pivotable element lying at a mutual distance, i.e. from close to the hinged connection 13 up to the free end of the pivotable element 11.

The pinions 12 of the transmission devices on either side of the frame 2 are mutually coupled by means of a continuous shaft 15. The shaft 15 can be driven rotatably by a motor with reduction unit 16. Figure 2 shows the displacement possibilities of the frame 2 of the feeding fence under the influence of the action of the drive device 10.

At I is drawn the furthest retracted position, which is also shown in figure 1. Ill is the moved forward position, while II shows an intermediate position.

As can be seen, the pivotable member 11 has a substantially constant profile and this is supported on the side 21 opposite the side with the engaging surface 20 by supporting rollers 22 which are bearing mounted in a holder 23 which is mounted for pivoting on the shaft 15 of pinion 12.

From consideration of figure 2 it will be apparent that by rotational driving of pinion 12 in counter¬ clockwise direction the feeding fence displaces from position I via position II to position III. With rotation of the pinion 12 in clockwise direction the feeding fence moves back. In position I the pivotable element 11 extends upward within the width of the frame, so that this pivotable element 11 does not obstruct the free passage in front of the feeding fence 1. This is important in arranging the feed in front of the feeding fence.

Nor in the intermediate position II does the end of the pivotable element 11 yet extend in front of the feeding fence. In position III there are no impeding parts of the drive device protruding in front of the feeding fence either.

Figures 3 and 4 show another embodiment. This is also a feeding fence 30 which can be moved reciprocally. Likewise incorporated in feeding fence 30 is a motor with transmission with which a pinion 31 mounted on feeding fence 30 can be rotatably driven. The pinion 31 is in engagement with a curved rack 32. By means of a shaft 33 the right-hand end of rack 32 is mounted hingedly on the support 34 which is fixedly connected to the floor.

The shaft 33 is moreover upwardly displaceable in a guide track 35 which is formed in the support 34. On the end of shaft 33 is mounted a roller 37 which protrudes into a guide track 36 formed integrally with the displaceable feeding fence 30. The guide track 36 extends obliquely upward. Figure 3 shows in dash-dot lines the starting position and in full lines a partly moved forward position. This figure shows that due to the co-action of the guide tracks 35 and 36 the hinge point 33 of the pivotable element 32 moves upward during the movement forward from the rearmost position. In the rearmost position the pivotable element extends upward and in the forward position of the feeding fence the pivotable element 32 is tilted forward.

Because the hinge point 33 moves upward, the pivotable element 32 remains clear of the ground.

As shown in figures 3 and 4, a holder with support rollers 38 is also used in this device to keep the pivotable element 32 in contact with the pinion 31.

In the device 40 of figure 5 a pinion 41 is likewise rotatably mounted on the frame 42. The frame 42 can perform a translation movement over the floor 43. A pivotable element 44 in the form of a curved gear rack is in engagement with pinion 41 and one end thereof is connected hingedly at 45 to an arm 46, which in turn is itself connected hingedly at 47 to a support 48 which is fixedly connected to floor 43.

A guide track 49 is formed on the frame 42. In this guide track engages a roller 50 which is arranged at the

position of the hinge connection 45 at the end of the pivotable element 44. Due to the mechanism formed by the arm 46 in combination with guide track 49, the hinge end of pivotable element 44 moves upward when frame 42 moves from the rearmost position shown with dash-dot lines in figure 5 to the shifted forward position. The shifted forward position is indicated with full lines in figure 5.

Due to the upward movement of the hinge end of pivotable element 44 this latter remains clear of the ground.

Although in figure 5 the arm 46 is drawn straight upward in the shifted forward position of the frame 42, this position will not be able to occur in practice if the device, as described, is used for reciprocating movement of frame 42. In the reverse application, wherein the reciprocating movement of the frame 42 was used for rotational driving of the pinion 41, this position could indeed occur. In the embodiment if figure 6 a manual drive is used. The displaceable feeding fence 60 of this figure comprises a frame 61 on which again the actual fence 62 is placed. Adjacently of the feeding fence is disposed a side fence 63. The drive 66 comprises a handle 67 which sets a rope pulley 69 into rotation by means of a right- angled transmission 68.

Mounted in frame 61 is a shaft 72 which bears a rope pulley 71 on its outer end. A V-belt 70 is placed round pulleys 69 and 71. On shaft 72 is also arranged a toothed wheel 65 which in this embodiment can be a chain wheel. The teeth of this toothed wheel 65 co-act with holes 75 in the curved pivotable element 64. This pivotable element is again hingedly connected via an arm 77 to a support 78 which is fixedly connected to the floor. A holder 76 provided with support rollers is pivotally mounted on shaft 72 and lies on the underside against the flange of pivotable element 64 which, as shown in figure 6, is

manufactured from a piece of angle iron. The support rollers of holder 76 hold pivotable element 64 in contact with toothed wheel 65. By turning the handle 67 the toothed wheel 65 is set into rotation and due to the co- action of chain wheel 65 and pivotable element 64 the feeding fence 60 is therein displaced. Although this is not shown, a tensioning device can act on the V-belt to ensure that a good friction contact is maintained between the V-belt and the rope pulleys. Instead of a V-belt a toothed belt or a chain can of course be used.

Arranged on the side of frame 61 is an angle profile 80 of which a protruding flange falls beneath a guide member which is likewise formed by an angle profile 81. The frame is hereby held firmly on the ground and the frame is prevented from being pulled upward by the action of the conversion mechanism.

Figures 7-9 show four displacement positions of a feeding fence 85, which is a further development of the feeding fence 1 of figures l and 2. Corresponding parts are designated with the same reference numerals.

The feeding fence 85 comprises, in addition to the components already described, a reaction element in the form of a pin 86 and, co-acting therewith, a second engaging surface in the form of a curved path 87, which is formed in a plate 88 fixed to the frame 2. The shape of the curved path 87 is easily defined as the path described by the reaction element 86 relative to the frame 2, wherein the movement of the frame 2 moves between the two extreme positions of the translation movement. Figure 8 thus shows the position of feeding fence 85 after an initial displacement wherein pinion 12 has moved forward over the first straight part of rack 11. The reaction element 86 of course moves therein relative to frame 2 in a straight line which is also to be found in the straight part 89 of the curved path 87. As soon as pinion 12 engages onto the curved part of rack

11 the reaction element 86 tilts upward, which can also be found in the upward curved part of the curved path 87.

It can be seen clearly that the curved path 87 extends in a direction which has at least a considerable component transversely of the translation movement. In other words, the curved path 87 itself extends generally in the direction of the translation movement.

The reaction element 86 consequently absorbs a reaction force directed substantially transversely of the translation movement, so that substantially only a force parallel to the translation movement is still exerted on the hinge 13. A possible tilting moment which the drive might exert on the feeding fence is hereby compensated.

It is self-evident that the placing of the reaction element and the curved path can be reversed, so that a curved path is arranged on the pivotable element 11 and the reaction element is fixed on the feeding fence.

By causing the pivot pin 13 to engage in a vertical slot, as described above and shown in figures 7-10, all vertical forces can be eliminated in embodying of the feeding fence 85 and a purely horizontal force engagement at a favourably very low level can be achieved.

As noted in the above description, the device according to the invention can be embodied in many different forms. The pivotable element can be embodied for instance as a curved gear rack or an angle profile with holes therein which co-act with a chain wheel. The invention is not however limited to such embodiments. Any assembly of an engaging wheel which can be in driving engagement with an engaging surface of an elongate element can be used for the present invention. One possibility (not shown) is for instance a gear rack formed by a roller chain enclosed in a curved C-profile. An important aspect of the embodiment according to fig. 11-13 is that the gear rack and the pinion are wholly enclosed in the bottom part of the fence. The enclosure is formed integrally with the end fence which is mounted fixedly on the floor. The feeding fence is

guided by the sliding beams in this casing of the gear rack.

The rear part of the end fences are open, so that during assembly the end fences are placed on the guide from the front. Hereby the end fences can moreover be kept short, wherein only the rear part of the fence still rests on the guide in the foremost position. The advantage of a short end fence is that the manure passageway is hereby narrowed as little as possible, which is favourable for the freedom of movement of the cattle.

In the foremost position the guide roller runs out of the guide rail but when it is moved back again the roller is picked up by the funnel shape at the entry of the guide rail.

In this construction the guide is independent of the floor. It is therefore not necessary to level the floor before the end fences are mounted. The feed passageway and the manure passageway can have a different height. As shown in fig. 11, the end fence can have a recess for passage of a manure scraper above the manure passageway which is located in the figure to the right of the fence.

When used in a feeding fence according to the invention it is advantageous to arrange the drive motor in the frame of the fence, so that with one continuous shaft a driving can take place at both ends of the fence. In that case the engaging wheel will therefore be mounted on the frame, while the pivotable element is hingedly connected to the floor. In another embodiment, wherein the drive is synchronized at both ends in another manner, the pivotable element can be arranged on the fence itself and the engaging wheel disposed fixedly. All these and like variants are deemed to fall within the scope of the following claims.