THIS INVENTION relates to improvements to animal treadmills and in particular to treadmills for exercising and conditioning of horses.

Treadmill conditioners presently in use for producing fitter show, racing and endurance horses normally include a movable conveyor belt on which the animal is supported and constrained to move thereon for exercising and conditioning purposes. In the known types of treadmills presently in use, the conveyor belt is often supported at an inclined attitude so that the animal is effectively moving in an uphill attitude so that maximum benefit is achieved from the treadmill. Furthermore in such treadmills, the speed of movement of the conveyor belt is normally fixed by a control unit operated manually by an operator and it is often difficult to judge the speed of a treadmill which suits the capability of the horse. The present invention aims to overcome or alleviate at least some of the above disadvantages by providing an improved treadmill the speed of which, or elevation of which is controlled in response to conditioning or other requirements of a particular horse. Other objects and advantages of the invention will become apparent herein.

With the above and other objects in view, this invention resides broadly in apparatus for the exercising and/or conditioning of animals such as horses comprising endless belt means having an upper run, means for constraining a said animal on said upper run such that said animal is forced to walk or otherwise move upon movement of said belt means, means adapted to be associated with said animal to detect the heart rate thereof, control means associated with said treadmill and adapted to vary the operating conditions thereof in accordance with said detected ^" heart rate.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherei r-

Figs,l and 2 are respective side and end perspective views of a treadmill according to the present invention in an elevated attitude; Fig. 3 is a side view of the treadmill illustrated in Figs. 1 and 2 in a lowered attitude and

Fig. 4 is a block diagram of a control system for use with the treadmill of the present invention. Referring to Figs. 1 to 3, there is illustrated a treadmill 10 according to the present invention which includes a first frame assembly 11 which in use is supported on the ground or say a concrete floor and a second frame assembly 12 which is connected to the first frame assembly 11 for pivotal movement about a horizontal axis disposed towards the rear of the frame assembly 11. Respective hydraulic rams 13 are preferably provided on either side of the treadmill 10 and extend between to interconnect the respective frame assemblies 11 and 12 so that pressurized fluid applied to the rams 13 will cause the frame assembly 12 to pivot upwardly from the position shown in Fig. 3 to the position shown in Figs. 1 and 2. Exhaust of fluid from the rams 13 will conversely permit the frame assembly 12 to be lowered to the Fig. 3 position. Supported on the frame assembly 12 is a movable conveyor assembly 14 including a movable endless belt supported about respective end rollers 15 and defining an upper belt run 16 for supporting the animal in use. A pair of side walls 17 are provided on either side of the conveyor assembly 14 to constrain the animal on the upper belt run 16. Preferably a ramp 18 is provided at the rear of the apparatus to facilitate passage of the

animal onto the upper belt run 16.

The forward portion of the treadmill 10 is closed by a flexible sheet 20 which extends between the respective side walls 17 and which may be turned upwardly to permit viewing of the horse's hooves in action on the treadmill. For this purpose, a U-shaped frame assembly 21 is pivotally connected at 22 to the forward portion of the respective side walls 17 and has the flexible sheet fixed to the transverse base member 23 thereof so that in the lowered position shown, the flexible sheet 20 closes off fully the forward portion of the'treadmill whilst in a second position the U-shaped frame assembly 21 may be pivoted upwardly thus lifting the sheet 20 to expose the lower portion of the horse's hooves to view. The conveyor assembly 14 is adapted to be driven by a variable speed hydraulic motor, preferably a variable displacement hydraulic motor connected to the rear end roller 15 which may be controlled in accordance with various conditions sensed in the animal. As shown more clearly in Fig. 4, the control system for the treadmill 10 includes in this embodiment a digital computer 24 which preferably has associated with it a display device or devices so that real time monitoring of all parameters can be achieved. Preferably the display device comprises a cathode ray tube type of device 25. Also associated with the computer 24 is a recording device 26 preferably in the form of a printer, floppy disc storage device or both so that the performance of animals on the treadmill may be recorded and evaluated.

So that various analogue signals sensed by transducers 27 associated with the apparatus may be converted to computer (digital) signals, an analogue-to- digital converter 28 is provided. A computer interface device 29 is also provided to connect all transducers 27 to the computer system, the device 29 also serving for the buffering and expansion of the computer signals

to control the treadmill 10. The interface device 29 also is provided with integral digital displays so that the computer control signals can be monitored to ensure correct operation of the treadmill 10. Coupled with the interface device 29 is a manual override system 30 which allows use of the treadmill 10 in absence of the computer 24 or its programmes.

Transducer 31 comprises a heart monitor which is adapted to be connected to the animal on the treadmill (represented schematically as 32) . The heart monitor- 31 is operative to sense the animal's electro- cardiac signals and convert those signals to digital pulses for the computer 24. In one form, the heart monitor 31 comprises a belt provided with a number of electrodes, two of which pick up the heart signals whilst electronic circuitry in the belt such as a monostable multivibrator is operable to convert the signals into digital pulses. In an alternative arrangement, the heart monitor 31 comprises a device clamped to the animal's ear to pick up increased blood pressure at the peak of each heart beat. In each instance the heart monitor 31 and associated circuitry are operable to provide digital pulses to the computer representing one pulse per heart beat. The control system also preferably includes a respiration monitor 33 preferably in the form of a heat sensitive device which is located in or near the animal's nostril/s which is respectively heated or cooled on each breath out or breath in of the animal. Heating or cooling of the heat sensitive device is sensed again by conventional electronic circuitry to produce one pulse per breath for interface with the computer 24 through the device 29. The respiration monitor 33 permits performance comparisons between different animals as well as permitting the monitoring of one animal over a period of time of a training programme. So that overstress or heat exhaustion of an

animal can be sensed, a temperature monitor 34 may be associated with the belt of the heart monitor 31. The temperature monitor 34 may comprise a thermistor, thermocouple or gas filled thermometer; however, preferably it comprises a miniature integrated circuit.

The temperature monitor 34 preferably provides an analogue signal converted by the A/D converter 28 into digital form for presentation to the computer 24. In the event of gross over temperature sensed by the temperature monitor 34, the computer 24 is operable to stop the treadmill 10. Alternatively, a high speed fan/s 35 is associated with the treadmill 10 to simulate the cooling effect of air in accordance with the normal pace of the animal. The fan 35 is arranged at the forward end of the treadmill 10 to direct air onto the animal or alternatively may communicate with ducts which open at the forward end of the treadmill to direct air rearwardly onto the animal. If over- temperature is sensed, the computer 24 is operable via the interface 29 and a fan servo control 36 to increase the fan speed and thereby the cooling flow of air.

The control system is operable to control the treadmill speed, or alternatively the treadmill elevation as determined by the rams 13 in accordance with heart rate 31 of the animal. For this purpose, the treadmill 10 includes a speed monitor 37 and an angle transducer 38. The speed monitor 37 preferably includes a spur gear or sprocket fixed for movement with one of the end rollers 15 to thereby revolve at a rate proportional to the speed of the treadmill belt 14. Preferably the gear or sprocket includes the maximum number of teeth possible so that the speed monitor 37 has the highest possible revolution and so that the accurate speed nonitoring can be achieved at low treadmill speeds. Sensing means, preferably of optical or electro-magnetic form, are associated with the gear or sprocket to sense the presence of

respective teeth and therefore the speed of the treadmill belt.

The angle transducer 38 is operable to sense elevations of at least plus or minus 20 degrees from horizontal because the work effort of the animal is directly related to the tangent of the measured angle. The angle transducer 38 may be in the form of a pendulum device or alternatively a linear displacement sensor extending between the frame assemblies 11 and a moving part of the treadmill 10 such as the cylinder of one ram 13. The signal sensed in either case comprises an analogue signal which is translated into digital form through the computer interface 29 and A/D converter 28. Servo controllers 39 and 40 are provided for control of the hydraulic elevating rams

13 and the hydraulic treadmill belt motor 41, respectively. The servo controller 39 for the elevating rarns _^ preferably includes hydraulic servo control valves operable to exhaust fluid from the rams 13 or apply fluid thereto from the pressure supply 42 in this instance an hydraulic pump. Feed-back from the angle transducer 38 assists in achieving the required elevation of the treadmill.

The speed servo controller 40 allows the computer 24 to adjust the speed of the treadmill 10 in accordance with the measured parameters and the internal programme of the computer. Preferably, the speed servo controller 40 includes a direct proportional value; however in an alternative arrangement the pump 42 may comprise a variable displacement pump controlled in a proportional manner by the servo controller 40. Alternatively, the motor 41 may comprise a variable displacement motor.

So as to provide power for operation of the treadmill 10, an electric, diesel or petrol motor 43 is provided to drive the hydraulic pumps and provide via a generator power for the electronic and electromechanical

controls .

In use, the animal is constrained on the moving belt run 16 and between the side walls 17 and the computer programmed for a fixed speed, such as a low speed walking pace, for a certain period of time so that the horse will warm up prior to the full exercise programme. During this warm up period, the treadmill may either be set at an elevated position or a substantially horizontal position. After the warming up period, during which the animal heart rate and temperature are sensed to ensure that they are "normal" relative to previously stored figures in the computer 24, the training programme for each individual horse comes into operation. For each horse a pre-determined heart rate limit is stored in the computer memory, the heart rate limit varying in accordance with the fitness of the particular horse. The treadmill speed and elevation of the unit are then set so as to provide the required exercise level to the horse and during this time the heart rate, respiration rate and temperature of the animal are continuously monitored. If, say, for any reason, the heart rate of the animal goes beyond the pre-determined limit, the elevation of the treadmill is lowered or alternatively the speed of the treadmill is reduced. Alternatively, both the treadmill speed and elevation are reduced.

Similarly, the speed and elevation may be increased so as to make the animal reach its pre¬ determined heart rate limit within a shorter period. Where for example the apparatus is to be used for train¬ ing trotters or pacers, the elevation of the unit may be set at "zero" so as to accord with the normal running attitude of the animal. In this arrangement, the animal may be worked in a harness. The maximum limits of respiration rate and temperature are also stored in the computer so that the treadmill speed or elevation of the treadmill reduced

or the speed of the cooling fan 35 increased in the case of overtemperature.

Also, preferably associated with the treadmill, are acceleration and deceleration controllers so that the rate of variation of speed can be varied so as not to cause sudden shocks to the system. Preferably also, emergency stop means are associated with the system which monitors the horse so that in say the case of a stumble, the apparatus will instantaneously stop. For this purpose, a harness may be fitted to the horse and carry the sensors for sensing heart rate,respiration rate, etc.- and be coupled into a system through a coupling cable which will pull apart say if the animal falls. This will automatically cause the treadmill motor 37 to stop. The computer 24 may also be programmed so that the angle of elevation is varied continuously to simulate cross-country training.

Although the system has been described in conjunction with control by a computer, conventional feed-back control networks may be substituted in lieu thereof.

Whilst the above has been given by way of illustrative example of the invention, it will of course be realised that many modifications and variations may be made to the above described embodiment by persons skilled in the art without departing from the broad scope and ambit of the invention as defined by the appended claims.