Abstract:
A hoof trimming stall has a front gate having two pivotally mounted spaced-apart doors for swinging inwardly and outwardly. The doors are movable between a catching position in which the doors point inwardly for receiving a head of the animal entering the stall, a closed position for holding the animal in the stall with the neck of the animal caught in a gap between the doors, and an open position in which the doors point outwardly for permitting the animal to exit. A door lock/release mechanism has a slider arm movable forward and backward, a hydraulic cylinder for moving the slider arm forward and backward, a rear catcher mounted on the slider arm for preventing the doors from moving from the closed position to the catching position, a front catcher mounted on the slider arm for preventing the doors from being opened by the animal when the doors are in the closed position, and a release mechanism for permitting the doors to move from the open position to the catching position. An automatic reset mechanism automatically resets the doors and door/lock release mechanism. The reset mechanism has a sensor for signaling the hydraulic cylinder to move the slider arm backwards when the doors are in the open position and a spring for biasing the doors from the open position to the catching position.

Description:
FIELD OF THE INVENTION 
   This invention is related to hoof trimming stalls for hoofed animals such as cattle, horses and the like. 
   BACKGROUND OF THE INVENTION 
   Large hoofed animals in a farm setting frequently require hoof trimming. Due to the size and weight of such animals, in order to trim their hooves safely, the animals are usually immobilized in a stall before hoof trimming is commenced. Although many commercial stalls are available for this purpose, currently available commercial stalls generally suffer from one or more disadvantages. For example, such stalls may not be portable. They may not securely immobilize the animal. Loading animals into such stalls may not be easy and/or quick. The stalls may not provide easy and/or quick access to the animal&#39;s hooves. Unloading animals from such stalls may not be easy and/or quick. As a result, precious time is lost during the hoof trimming operation resulting in fewer animals that can have their hooves trimmed in a given period time. 
   De Vor&#39;s Deluxe Hoof Trimming Chute as advertised in a brochure of February 2004 by De Vor Enterprises shows a stall having many advantageous features. While that chute represented an improvement over existing hoof trimming stalls of that time, there remains a need in the art for a stall that provides improved security, convenience, versatility and/or throughput. 
   SUMMARY OF THE INVENTION 
   As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. 
   In accordance with the present invention, there is provided a hoof trimming stall comprising: a frame having a rear portion through which a four-legged hoofed animal may enter the stall and a front portion through which the animal may exit the stall; a front gate on the front portion of frame, the front gate having two pivotally mounted spaced-apart doors for swinging inwardly into the stall and outwardly away from the stall, the doors movable between a catching position in which the doors point inwardly for receiving a head and neck of the animal entering the stall in a gap between the spaced-apart doors, a closed position for holding the animal in the stall with the neck of the animal caught in the gap between the doors, and an open position in which the doors point outwardly for permitting the animal to exit the stall; a door lock/release mechanism having a slider arm movable forward and backward with respect to the frame, actuating means connected to the frame for moving the slider arm forward and backward, a rear catcher mounted on the slider arm for preventing the doors from moving from the closed position to the catching position, a front catcher mounted on the slider arm for preventing the doors from being opened by the animal when the doors are in the closed position, and a release mechanism for permitting the doors to move from the open position to the catching position; and, an automatic reset mechanism for automatically resetting the doors and door/lock release mechanism, the reset mechanism having a sensor for signaling the actuating means to move the slider arm backwards when the doors are in the open position to thereby reset the door lock/release mechanism, and a biasing means connected to the doors and the frame for biasing the doors from the open position to the catching position to thereby reset the doors. 
   The front and rear catchers prevent the doors from moving outwardly or inwardly when the doors are in the closed position. There will be some “play” between the catchers since the catchers cannot be too tightly spaced as to cause the doors to bind when they are allowed to move to the open position or back to the catching position. The rear catcher is preferably pivotally mounted on the slider arm. Similarly, the front catcher is preferably pivotally mounted on the slider arm. Pivoting catchers facilitate automatic resetting of the doors after the animal exits the stall. 
   The release mechanism permits the doors to move from the open position back to the catching position. Preferably, the release mechanism comprises a pair of interacting elements, for example plates, wherein one member causes the other member to shift the position of a catcher out of the way of the doors. More preferably, the release mechanism comprises a lift plate connected to the rear catcher for engagement with the front catcher and/or a push plate connected to the front catcher for engaging the rear catcher. Even more preferably, the release mechanism comprises a lift plate connected to the rear catcher and a push plate connected to the front catcher for engaging the rear catcher to release the rear catcher as the doors move from the open position to the catching position. 
   The doors preferably comprise rollers mounted thereon to engage the rear catcher to permit movement of the doors without binding when the doors move from the catching position to the closed position. The rollers are preferably located at the top of the doors. The rollers may also help prevent binding of the doors when the doors move from the closed position to the open position. 
   Preferably, the doors also have a half-release position between the closed position and the open position. The half-release position provides enough room for the animal to start pushing through the doors to exit the stall. As a result of the animal pushing through the doors at the half-release position, the doors move from the half-release position to the open position allowing the animal to exit fully from the stall. To move the doors to the half-release position, the stall preferably comprises a controller for permitting selective activation of the actuating means, preferably a hydraulic cylinder, for moving the slider arm and doors forward from the closed position to the half-release position. 
   Automatic resetting of the stall as the animal exits is preferably activated only after the doors are pushed past the half-release position by the animal. This prevents spooking of the animal who might try to retreat back into the stall if the slider arm starts to move and under pressure from the biasing means connected to the doors. The biasing means may be any suitable means, for example, another hydraulic cylinder, a spring, etc. A spring is particularly preferred. 
   The stall preferably comprises means for preventing an animal from backing out of the stall. For example, straps, chains or arm elements may be used. Preferably, the stall comprises a rear swing arm for blocking the rear portion of the frame to help prevent the animal from backing out of the stall. 
   The stall preferably has leg supports for suspending the front and rear legs at a higher level for convenience of trimming. For example, straps, chains and/or platforms may be used. The front legs are preferably supported on platforms to which the legs are secured by leg holders (e.g. straps, ropes). The rear legs are preferably supported one at a time by a strap or chain secured to the leg. The means for suspending the legs may be height adjustable. 
   The stall also preferably has an animal lift for supporting the animal while its legs are raised for trimming. The animal lift is preferably adjustable to accommodate animals of different size. The animal lift preferably comprises adjustable arms and a belly strap attached to the arm. The animal lift is preferably hydraulically activated by one or more hydraulic cylinders. 
   The stall preferably comprises a floor. The floor is preferably vertically movable, preferably to raise and lower the entire stall to a convenient height. Vertical movement of the floor is preferably accomplished by a floor lift, for example one or more hydraulic cylinders. The floor may be supported on vertically adjustable legs, or may be supported directly by a hydraulic jack. 
   Preferably, the animal lift and the floor lift are separately controllable. Both the animal lift and the floor lift are preferably controlled by separate worker/slave hydraulic cylinders. 
   The stall is preferably portable in that it may be conveniently taken from site to site. Preferably, the stall comprises wheels connected to the frame and a removable hitch to permit towing of the stall. Preferably, the wheels are mounted on an axle. More preferably, the axle may be raised and lowered. 
   The hoof trimming stall of the present invention provides faster throughput of animals. The stall is particularly useful for cattle and horses. 
   Further features of the invention will be described or will become apparent in the course of the following detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the invention may be more clearly understood, embodiments thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  is a top left front side perspective view of a hoof trimming stall of the present invention; 
       FIG. 2  is a left side view of the hoof trimming stall of  FIG. 1 ; 
       FIG. 3  is a right front side perspective view of the hoof trimming stall of  FIG. 1 ; 
       FIG. 4  is a bottom perspective view of the hoof trimming stall of  FIG. 1 . 
       FIG. 5  is a magnified top front view of the hoof trimming stall of  FIG. 1  at the top of the doors; 
       FIG. 6  is a magnified top left front view of the hoof trimming stall of  FIG. 1  at the top of the doors; 
       FIG. 7  is a magnified bottom right front view of the hoof trimming stall of  FIG. 1  at the top of the doors; 
       FIG. 8  depicts a slider arm used on the hoof trimming stall of  FIG. 1 ; 
       FIG. 9  depicts a rear catcher used on the hoof trimming stall of  FIG. 1 ; 
       FIG. 10  depicts a front catcher used on the hoof trimming stall of  FIG. 1 ; and, 
       FIGS. 11A to 11C  are a schematic diagram illustrating the positions of front and rear catchers as doors are being reset to a catching position. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring generally to the Figures, a hoof trimming stall has a frame including front side support struts  1 , rear side support struts  2 , roof  3  and floor  4 . Front gate  10  mounted at the front of the stall has two side-by-side spaced-apart doors  11  shown in a catching position in  FIG. 1 . Doors  11  are constructed of cylindrical pipes and are pivotally mounted on the frame at fixed points at the top and bottom alongside front side support struts  1  so that the pivot axis is parallel to front side support struts  1 . The doors comprise vertical head rails  13  adjustably attached to head plates  14  proximal the top and pivotally attached to the doors at the bottom. The head rails define a gap between the doors, which is large enough in the catching position to accommodate the head of animal but small enough to prevent the entire animal from passing completely between the doors in the catching position. When an animal enters the stall from the rear, the animal&#39;s head passes through the gap and the animal&#39;s shoulders push the doors to a closed position wherein the doors are coplanar and the animal&#39;s neck is caught in the gap between the doors. 
   Referring specifically to  FIGS. 5 ,  6  and  7 , close-up views of the top of doors  11  show head rails  13  attached to head plates  14  by means of pins  16  through one of a plurality of holes  17  in each head plate  14 . The size of the gap between the head rails may be adjusted by securing the head rails in the head plates at different holes. Rollers  15  are rotatably mounted on top of head rails  13 . Doors  11  pivot on gate drive plates  18  that are attached to swing arms  19 . Swing arms  19  ensure coordination of the doors as they swing outward or inward. 
   Referring generally to the Figures, a door lock/release mechanism comprises slider arm  20  slidably attached to the frame on the roof. The slider arm may be moved backward and forward by hydraulic cylinder  21  attached to the slider arm and the roof. Rear catcher  30  and front catcher  70  are pivotally mounted on the slider arm. Rollers  15  are rearward of rear catcher  30  when doors  11  are in the catching position. As the doors move from the catching position to the closed position, doors  11  engage the rear side of rear catcher  30  causing the rear catcher to pivot up and away from the doors to permit the doors to pass under the rear catcher into the closed position. Rollers  15  ensure that the doors do not bind on the rear catcher as the doors engage the rear catcher. Once the doors move from the catching position to the closed position, front catcher  70  prevents the animal from pushing the doors outward and rear catcher  30  prevents the doors from moving inward. Thus, the doors are locked in the closed position with the animal&#39;s neck between head rails  13 . 
   Details of slider arm  20 , rear catcher  30  and front catcher  70  are shown specifically in  FIGS. 8 ,  9  and  10 . Slider arm  20  comprises front catcher holder  24  and rear catcher holder  25  fixedly attached to the slider arm at the end and inward from the end, respectively. Rear catcher  30  comprises rear horizontal catcher bar  31  having angled portion  35 , sleeve  32  and lift plate  33 . Rear catcher  30  is pivotally mounted to the slider arm by a pin through sleeve  32  and through apertures  27  of rear catcher holder  25  on the slider arm. Angled portion  35  permits the doors to more easily cause the rear catcher to pivot up and away from the doors as the doors move from the catching position to the closed position as described above. Front catcher  70  comprises front horizontal catcher bar  71 , sleeve  72  and push plate  73 . Front catcher  70  is pivotally mounted to the slider arm by a pin through sleeve  72  and through apertures  26  of front catcher holder  24  on the slider arm. The front and rear catchers are depicted upside down to better illustrate the elements of which they comprise. 
   Push plate  73  and lift plate  33  together form a release mechanism for disengaging rear catcher  30  to permit the doors to move to the catching position. Push plate  73  of the front catcher engages lift plate  33  of the rear catcher when the front catcher pivots in response to the doors moving toward the catching position as more fully described below. Pivoting of the front catcher up and away as the doors move toward the catching position causes push plate  73  to push on lift plate  33  thereby causing rear catcher bar  30  to pivot up and out of the way of the doors as the doors pass beneath the catchers. Rear catcher  30  may also be equipped with a safety handle (not shown) to pivot the rear catcher manually so that the doors may be allowed to move to the catching position. 
   With an animal in the stall in the closed position, the stall may be raised to a comfortable height by action of hydraulic cylinders  40  attached to floor  4  and lifting legs  41 . Lifting legs  41  are connected at a scissors linkage and wheels  42  at the ends of legs  41  permit the legs to ride easily along the ground as hydraulic cylinders  40  push the legs closer together thereby raising the stall higher off the ground. One hydraulic cylinder is a master with the other a slave. It should be noted that removable hitch  43  is removed before loading animals. Trailer wheels  44  are raised off the ground by virtue of hydraulic cylinder  45  attached to a liftable axle  140  on which wheels  44  are mounted. Thus, floor  4  can be as close to the ground as legs  41  will permit in order to load the animal in the first place. When the stall is as close to the ground as possible, it rests on the ground on feet  148 . Raising of the stall lifts wheels  44  further off the ground.  FIG. 1  depicts the stall with trailer wheels  44  in the lowered position for transporting the stall and  FIG. 2  depicts the stall with trailer wheels  44  in the raised position. 
   With an animal in the stall in the closed position, a belly band (not shown) attached to adjustable support arms  50  is slung under the belly of the animal behind the front legs of the animal. The support arms are attached to hydraulic cylinders  51 , which are attached to the frame. One of the cylinders  51  is a master and the other a slave. The animal is supported by the belly band which is raised and lowered by the support arms in response to actuation of the hydraulic cylinders. The support arms are adjustable in length to accommodate different seized animals. Rear end swing arm  55  pivotally attached to the frame may be swung down behind the animal by means of hydraulic cylinder  56  to prevent the animal from backing out of the stall. Once the animal leaves the stall, hydraulic cylinder  56  raises swing arm  55  so that another animal may enter the stall. 
   Attached to front side struts  1  are front leg trimming platforms  60  set at a height where a typical sized animal can comfortably have its leg set in a tucked-under position. Front leg holders (e.g. straps or ropes) (not shown) are used to secure the front legs on the trimming platforms. The front hooves may then be trimmed. One of the back legs of the animal may also be lifted and placed in a rear leg support chain or strap (not shown) to suspend the rear leg at a comfortable height for trimming the hoof. The rear leg support chain or strap is suspended from a roller (not shown) for ease of raising and lowering. After the rear hoof of the suspended leg is trimmed, the rear leg support may be used on the other rear leg so that the hoof on the other rear leg may be trimmed. After trimming all of the hooves, the front and back legs are released and the belly band removed from around the animal. 
   To release the animal from the stall, doors  11  are selectively opened by an attendant by activating hydraulic cylinder  21  to move slider arm  20  forward which pushes the doors open to a half-release position. The doors are pushed open by virtue of the front face of rear catcher  30  pushing against rollers  15 . The doors are not blocked by front catcher  70  since the front catcher also moves with the slider arm. As the doors swing open to the half-release position, the rollers get farther apart until at some point they are farther apart than the length of front catcher  70 . Since rear catcher  30  is longer than front catcher  70 , the rollers continue to engage the rear catcher in the half-release position to prevent the doors from moving inward. The animal is then encourage to push forward thereby pushing the doors open to an open position, which is wide enough for the entire animal to exit through the front of the stall. 
   When doors  11  are pushed past the half-release position by the animal exiting the stall, laser sensor  65  mounted on one of the doors  11  below gate drive plate  18  detects the opening of the doors and signals hydraulic cylinder  21  to retract thereby moving slider arm  20  backwards to reset the slider arm in its original position. Once the animal has fully exited the stall, doors  11  are pulled back toward the catching position by springs  66 , 67  (only shown in  FIG. 5 ) connected to swing arms  19 . With specific reference to  FIGS. 11A to 11C , as the doors engage the front face of front catcher  70 , the front catcher pivots up and away from the moving doors. Pivoting of the front catcher causes push plate  73  to push against lift plate  33  of rear catcher  30  thereby causing rear catcher  30  to pivot up and out of the way of the doors. The doors may then pass beneath both the front catcher and the rear catcher to reach the catching position. Once the doors have fully passed the catchers, both catchers pivot back to their original positions. In this manner, resetting of the front gate is accomplished automatically, saving considerable time. 
   When the stall is being used to trim an animal&#39;s hooves, hitch  43  is removed and trailer wheels  44  are raised off the ground as explained previously. For transportation, wheels  44  may be lowered by means of hydraulic cylinder  45  attached to the liftable axle and hitch  43  can be quickly and conveniently mounted on to floor  4  of the stall. As shown generally in the Figures, with special reference to  FIG. 4 , hitch  43  comprises a pair of spaced-apart brackets  46  with aligned apertures for receiving a pin and hitch pin  48  for insertion into an aperture in floor  4  of the stall. To mount the hitch, hitch pin  48  is inserted into the aperture in floor  4  and the spaced-apart brackets are fitted over sleeve  47  mounted at the front of the frame. A pin is inserted through the aligned apertures of the brackets and through the sleeve to secure the hitch to the stall. Cotter pins, chains or other safety devices may be used to ensure that the pin does not release from brackets  46  and sleeve  47  during transport. Hitch  43  also comprises trailer ball mount  49  and handles  149 . The hitch may also comprise a trailer wheel, particularly if the hitch is very long. 
   All of the hydraulic cylinders are operated by a 5 horsepower motor  80  mounted on roof  3 . The motor actuates the hydraulic cylinders with a 7 gallon oil pump. For operating all solenoids on the motor and hydraulic cylinders, a 1-phase 220 V to 3-phase 110 V transformer is used. All of the lifting functions of the stall are electrically controlled and controlled separately. This provides the ability to adjust the height of the stall for worker convenience while providing the ability to manipulate the animal to whatever position is desired. 
   The stall comprises a number of other advantageous features. Door holder  101  comprising a pin and sleeve mechanism may be used to hold the doors in the open position for transport. Swingable lighting tower  110  having lights mounted thereon provides lighting from any number of angles and positions. Electrical cord boom  111  supports electrical cord for 220 V service. Control box racks  115  on both sides of the stall support control boxes (not shown) on both sides of the stall so that all of the electrical functions may be controlled from either side. A heat gun holder  116  provides a convenient place to store a heat gun. 
   In a typical hoof trimming operation, the stall is transported to a site (e.g. a farm) by a towing vehicle and disconnected from the towing vehicle. Legs  41  are lowered by hydraulic cylinders  40  so that the stall is supported on wheels  42 . Trailer wheels  44  are raised off the ground by hydraulic cylinder  45  and the stall is lowered as far as possible to the ground. Front gate  10  is set in the catching position with rear swing arm  55  in the raised position. An animal, for example a cow, is loaded head-first through the rear portion of the stall. The cow&#39;s head and neck pass between head rails  13  and the cow&#39;s shoulders push doors  11  into the closed position where front and rear catchers  70 , 30  lock the doors in place with the neck of the cow caught in the gap between the head rails. Rear swing arm  55  is brought down behind the cow by means of hydraulic cylinder  56 . The belly band attached to adjustable support arms  50  is slung under the belly of the cow behind the front legs of the cow and the belly band is tightened by hydraulic cylinders  51  to support the cow. The entire stall is raised to a comfortable height by actuating hydraulic cylinders  40  attached to legs  41  of the stall. The front legs of the cow are placed on trimming platforms  60  and secured with the front leg holders. One of the rear legs of the cow is lifted off the floor and suspended with the rear leg support chain or strap. The hooves of the three legs are trimmed. The suspended rear leg is released lowered and the other rear leg is suspended and trimmed. All of the legs of the cow are then released and lowered and the belly band is removed from under the belly of the cow. The stall is lowered as far as possible by actuating hydraulic cylinders  40  attached to legs  41  of the stall. Hydraulic cylinder  21  is actuated to move slider arm  20  forward thereby pushing doors  11  to the half-release position. The cow is encouraged forward and the exiting cow pushes the doors open to the open position. The slider arm is automatically reset by hydraulic cylinder  21  and the doors are automatically reset to the catching position by the springs. The process is then repeated. 
   Other advantages which are inherent to the structure are obvious to one skilled in the art. The embodiments are described herein illustratively and are not meant to limit the scope of the invention as claimed. Variations of the foregoing embodiments will be evident to a person of ordinary skill and are intended by the inventor to be encompassed by the following claims.