This invention is related to a training device comprising at least
one wheel rotatable by the training, a fluid pump connected to the wheel and drivable
thereby and valve means on the pressure side of the pump for controlling the resistance
exerted by the fluid pump to the rotation of the wheel. It is preferred that the
device is constituted by a carriage adapted to be driven by a horse, which accordingly
is the training.
A carriage of the kind defined hereinabove is previously known by
SE, B, 420 185. In the known device said valve means is formed by a regulatable
load valve which is stated to be for instance a needle or ball valve. In order
to adjust the brake load by means of the fluid pump the driver has to readjust
the valve. Furthermore, the valve is stated to have the character of a regulatable
choke valve. When a certain choking condition has been adjusted by the driver,
this condition remains until the driver carries out readjustment. The present invention
is based upon the understanding obtained by thorough physiological studies that
such a design does not give rise to any entirely satisfactory training result.
The reason therefor is that when the driver has adjusted a certain choking condition
for the choke valve, this does not mean that the brake power exerted remains constant
in practice during the subsequent braking period. Due to natural circumstances,
such as tiredness of the horse, different ground causing different rolling resistance,
different inclination of the ground etc, the propelling speed of the carriage will
vary considerably. This causes a varying operational speed of the fluid pump, which
in turn gives rise to varying flow of fluid. Since the choking condition of the
choke valve remains, this will in practice cause a considerable change of the real
brake load to occur during the training period. Such a varying braking load does
of course give rise to varying resistance to the movement of the horse in the
shafts of the carriage. Such variation is extremely unfortunate since it has been
found, in said physiological studies, to be essential that the brake power applied
on the carriage is generally constant in order to obtain optimal and lenient training
of the horse.
Other prior art is represented by SE, B, 429 948. A training carriage
is disclosed therein having fluid pumps connected to the axles of carriage wheels.
The pumps pump oil from a tank via a regulating valve back to the tank. In order
to change braking power, the operator must manually manipulate the regulating valve.
DE, C2, 3 335 895 and EP, A2, 0 085 962 disclose that constant pressure
valves are known per se in hydraulic applications although they apparently have
not been proposed for the training device field as defined in the pre-characterizing
part of claim 1.
SUMMARY OF THE INVENTION
The object of the present invention is primarily to devise a training
device by means of which it should be possible to conduct training as physiologically
optimal as possible, i.e. training of such a nature that the resistance exerted
by the fluid pump to rotation of the wheel is generally constant; variables such
as rotational speed of the wheel, state of wear of the fluid pump and so on should
not have any considerable influence on the braking power exerted. Furthermore,
braking power should be regulatable rapidly and efficiently.
This primary object is according to the invention primarily obtained
by means of what is defined in the characterizing portion of claim 1.
A secondary object of the present invention is to devise a preferable,
from the constructional point of view, design of a carriage intended for training
horses and comprising at least one wheel, which is rotated when the carriage is
driven and which is drivingly connected to a fluid pump adapted to exert a resistance
to the rotation of the wheel. More specifically the unfavorable friction dependent
driving of the fluid pump proposed in SE, B, 420 185 should thereby be avoided.
Furthermore, the design should be such that it becomes economically favourable
with regard to the wheel suspension and furthermore, the wheel should be easy to
mount and dismount respectively.
This secondary object is obtained by providing the device with the
features more specifically defined in the characterizing portion of claim 9. Thanks
to this design, the protruding axle of the fluid pump will accordingly operate
for axial and radial support of the wheel relative to the fluid pump and thereby
relative to the carriage. The axle freely projecting outwardly from the fluid pump
at one end means, furthermore, that the wheel readily may be threaded on to the
axle and secured by means of one single securing member. Thus, the axle bearings
contained in the fluid pump will also operate as bearings for the wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
With reference to the enclosed drawings, a more close description
of an embodiment example of the invention will follow hereinafter.
In the drawings:
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
- Fig 1 is a partially cut view of a portion of a training carriage illustrating
the suspension of one of its wheels;
- Fig 2 is a diagrammatical view of the fluid circuit according to the invention;
- Fig 3 is a diagrammatical view illustrating the design of an electric control
unit contained in the training device; and
- Fig 4 is a diagrammatical view illustrating control and supervising possibilities
of the device and, at the bottom, a training program which can be executed by means
of the device.
A portion of a training carriage 1 is illustrated in Fig 1, said
carriage being intended to be pulled by a horse or other animal to be trained.
The carriage is in practice a two-wheeler although only one wheel 2 appears in
Fig 1. Furthermore, the carriage comprises a chassis only partially indicated,
said chassis being adapted to be connected to the horse by means of shafts or
the like and a seat for the driver being arranged on said chassis. The specific
design of the carriage is not essential to the concept of the invention; any carriage
or sulky design may in principle be used in connection with the invention.
When the carriage is propelled the wheel 2 is put into rotation by
its contact with the ground. A fluid pump 4 is connected to the wheel 2 and drivable
thereby. In practice, the pump is a hydraulic pump. The hydraulic diagram is more
specifically illustrated in Fig 2 and it appears also therefrom that two hydraulic
pumps 4 are arranged, namely one for each of the wheels of the carriage.
Valve means 5 are arranged on the pressure side of the pumps for
controlling the resistance exerted by the fluid pumps against rotation of the wheels.
Said valve means comprise a pressure restriction valve 6 of the automatically operating
constant pressure type, i.e. a valve to maintain a generally constant pressure
on the pressure side of the pumps 4 independently, at least within a certain pump
speed range, of the operational speed and thereby flow of the fluid pump. As appears
from Fig 2, the pumps 4 are on their pressure side provided with lines 7, which
run together and via a common line section 8 is in communication with the pressure
restriction valve 6. It is to be pointed out that said valve is of a design known
per se and used within other technical areas.
The suction sides of the pumps 4 communicate, in a manner conventional
per se, via lines 9 with a hydraulic oil container 10 arranged at a suitable location
on the carriage.
The pressure restriction valve 6 is adjustably designed as to the
magnitude of the constant pressure. A manometer 11 is arranged on the pressure
side of pumps 4 to deliver information regarding the pressure prevailing in the
hydraulic oil volume between pumps 4 and pressure restriction valve 6. It is suitable
to have the manometer 11 scaled in such a way that the measurement values which
can be read give an appreciation of the traction force, which the braking resistance
of the hydraulic pumps 4 give rise to in the shafts of the carriage or in another
analogous coupling device between the carriage and the horse. Such a scaling makes
it easier for the driver to make, based upon experience, such a correct readjustment
of the valve 6 that the desired resistance against displacement of the carriage
and being optimal for the training is exerted.
Besides, the valve means 5 comprise a regulatable valve member 12
for relieving the pressure on the pressure side of pumps 4. Said valve member 12
is more specifically constituted by a second regulatable valve arranged parallel
to the pressure restriction valve 6, said valve member forcing, in a first closed
position, the hydraulic oil on the pressure side of the pumps 4 to pass via the
valve 6 and allowing, in a second poen position, hydraulic oil to pass through
without having to pass through the pressure restriction valve 6. The valve 12 is
accordingly formed by a two position valve being in open or closed position.
On the down stream side of the valves 6 and 12, lines extending from
the valves run together into a common line 13, which via a filter 14 delivers the
hydraulic oil to container 10. A check valve 15 is in a conventional manner arranged
parallel to filter 14 and adapted to open in case the filter 14, e.g. due to clogging,
causes a resistance to flow exceeding a certain level.
The valves 6 and 12 are preferably co-ordinated to a valve block
indicated by means of the rectangle 15, control members for adjusting the constant
pressure level of the pressure restriction valve 6 and for regulating the valve
12 between its two positions being accessibel on the exterior side of said block.
In the most simple embodiment, these control members are conceived to he manually
operable by the operator or driver. It is then preferred that the valve 12 is of
such a design that it remains in one position, into which it has been adjusted
by manual actuation, until the valve again is actuated for transfer to the alternative
The arrangement of the two position valve 12 has the essential advantage
that the braking power may be regulated rapidly and efficiently in the sense that
the braking power may be put on and off respectively without any need to carry
out readjustment of the valve 6.
An example of a possible training program is illustrated at the bottom
in Fig 4. The abscissa here refers to time whereas the ordinate refers to the braking
power F. It may desirable during a first time period t1 to maintain a relatively
high braking power so that accordingly the horse must work relatively hard. During
this time period, the valve 12 in Fig 2 is accordingly closed whereas the valve
6 in dependence upon its adjustment maintains the braking power generally constant.
During a subsequent time period t2 the braking power will then entirely be eliminated
so that the horse will get a recovery period. Thus, the valve 12 in Fig 2 is open
during this period so that the hydraulic oil flow generated by pumps 4 may flow
to container 10 generally without resistance. This means that the resistance exerted
in the system according to Fig 2 is generally only constituted by frictional and
flow losses in the pumps and lines. Thereafter additional time periods t1, t2 etc
will follow. In other words, the training program described will cause an efficient
so called interval training which may be executed with a minimum amount of risk
for damages on the horse since the horse does not have to conduct the training
with a maximum speed.
In order to execute the training program illustrated at the bottom
of Fig 4 with a manually controllable embodiment of the device according to the
invention, the driver must, accordingly, operate the valve 12 between its two positions
with desired intervals. Delays in the system result in the somewhat sloping flanks
of the curve in Fig 4 without particular measures. Thereby the transition between
the working periods with a high braking power and the recovery periods becomes
However, it is preferred according to the invention to provide a
control unit programmable with a desired training program so that, accordingly,
the driver does not have to carry out any adjustment operations during the training
program proper provided that the training proceeds in a normal way. However, it
is of course possible that the driver must intervene if it turns out that the horse
either is not capable of managing the training program in question or has a considerably
higher capacity than the one expected. In the former case the driver could reduce
the pressure level determined by valve 6 by adjustment thereof and thereby reduce
the braking power and in the latter case the braking power could be increased by
adjusting valve 6.
The control unit according to Fig 3 comprises electrical output leads
16, 17 for control signals. These leads are connected to valve 12 so that when
voltage is applied on the leads 16 and 17 valve 12 assumes one of its positions
whereas in absence of supply voltage on leads 16 and 17 the valve assumes its second
position. The device may for instance be such that the valve 12 may be arranged
to normally be in its open position as a consequence of the spring diagrammatically
indicated in Fig 2. However, when an actuation member associated to valve 12 receives
supply voltage via leads 16 and 17 in Fig 3, the actuating member of valve 12 actuates
the valve so that it is put into its second position, in which the valve closes
hydraulic oil flow. It is to be pointed out that valve 12 of course could be of
such a design that it simultaneously is operable manually by the driver and automatically
by means of the control circuit illustrated in Fig 3.
The control unit according to Fig 3 receives supply voltage from
a battery 18 and comprises suitably a main switch 19. Furthermore, the control
unit comprises time regulating members 20, 21 to determine the duration of the
entire training program and the duration of successive time periods t1 and t2 with
and without braking power application. The control unit comprises a start switch
22, the actuation of which by the driver gives rise to initiation of the training
program. The time delay member 20 is so designed that it comprises an adjustment
member for adjusting the duration of the training program. Accordingly, when the
driver actuates switch 22 the time regulating member 20 is put into operation and
it closes then, by means of the switch 23, the current supply to the time regulating
member 21, which has the character of a pause-run time relay. More specifically,
the time regulating member 21 operates so that it, when it receives supply voltage,
operates the switch 24 so that a supply voltage is obtained on leads 16 and 17
and accordingly the valve 12 is adjusted so that braking power application is
obtained. Also the time regulating member 21 is adjustable as far as pause time
and run time is concerned, i.e. adjustable as concerns t1 and t2 (Fig 4). When
the adjusted time for t1 has expired, member 21 opens via switch 24 the current
supply via leads 16 and 17 so as to initiate a pause period t2 and valve 12 is
then also reversed so as to admit the hydraulic oil flow to pass through. In this
way member 21 provides alternating closing and opening respectively of the current
supply via leads 16 and 17 until the training program after expiration of the set
time is interrupted by the member 21 braking the current supply to the member 21
via switch 23. The switch 24 of member 21 then brakes the supply via leads 16
The control unit described and in accordance with Fig 3 has the decisive
advantage that an experienced horse trainer in advance may establish the training
programs to be executed and less skilled assisting personnel may then take care
of the practical driving of the horse during the training program during execution
thereof by the control unit according to Fig 3.
It should be pointed out in this connection that it would of course
be possible to use, instead of the design of the control unit described in Fig
3, a computer which could be programmed with a great number of different training
programs, among which the one aimed at for the time being could be selected.
At the top in Fig 4 a conceivable design of a control panel 25 is
illustrated. The panel is located on the carriage so that it is conveniently accessible
to the driver. A first control member 26 could have the purpose to enable adjustment
of the duration of t1. A second control member 27 could serve for adjustment of
the duration of t2. The control member 28 could be adapted to enable adjustment
of the braking power during the time period t1, i.e. adjustment of the constant
pressure value of valve 6. Finally, control member 29 could have the purpose to
enable time adjustment of the duration of an entire training program, i.e. the
running time of member 20.
For the rest, the control panel could comprise the switch 22 illustrated
in Fig 3, by means of which the training program may be initiated and interrupted
respectively. An additional control member 30 could be arranged for manual adjustment
of the valve 12 between its positions. The control member 30 could be designed
as being in direct mechanical contact with valve 12 or alternatively in indirect
electrically operated connection to the valve.
Furthermore, it is preferable that control panel 25 comprises an
indicator 31, which is associated to a pulse sensor arranged on the horse and which,
accordingly, is adapted to display the pulse for the time being. An additional
indicator 32 could be arranged to display the speed of the equipage. Furthermore,
the device according to the invention could comprise or be connected to a registration
device of the printer type or electronical memory type to be able to store relevant
information about the training program. The load conditions illustrated with the
assistance of Fig 4 and the pulse of the horse, which is indicative of the strain,
are then primarily in view.
The use of the constant pressure valve 6 involves the advantage that
the braking power is generally the same independently of the speed of the carriage
and independently of the hydraulic pumps 4 being more or less worn. It is neither
of any consequence to the actual braking power whether the temperature and accordingly
the viscosity of the hydraulic oil varies during the execution of the training
program due to heating by friction; the constant pressure valve 6 automatically
compensates for such variations.
As appears from Fig 1, wheel 2 is mounted on an axle 33 projecting
from the pump 4 and secured against rotation relative to said axle, whereas the
body or housing 34 of the pump is attached to the carriage 1, e.g. by a bolt connection
penetrating through a plate like portion 35 of the chassis 3 of the carriage.
The projecting axle 33 of the pump 4 will thereby operate for axial and radial
support of the wheel 2 relative to the pump and thereby relative to the carriage.
The axle 33 projecting from the pump with one end allows a very simple mounting
of the wheel 2. More specifically, the wheel 2 comprises a hub 36, which may be
threaded onto the axle 33 and be secured thereto against relative rotation by means
of a key 37 or similar. The internal cavity in the hub 36 comprises portions having
two different diameters. A washer 38 contacts a shoulder formed in the transition
between these two portions and a screw 39 penetrates the washer, abuts with its
head against the washer and engages with its threaded shaft in an internally threaded
hole in the extreme end of axle 33. Thus, the hub 36 is actuated towards an abutment
40 on the axle 33 by the screw 39 and washer 38. From what is described it appears
that the wheel 2, the rim of which, not illustrated in Fig 1, may be connected
to the hub 36 by spokes 41, rapidly and readily may be released from the axle 33
and that the pump 4 itself will act as a bearer of the wheel 2 relative to the
chassis of the carriage.
The pump 4 is in the embodiment according to Fig 1 conceived to be
secured in a rigid manner to a rigid chassis portion of the carriage. It would
of course be possible to secure the pump 4 to such a carriage portion which could
be resiliently movably connected to the carriage chassis so that in this way a
resilient wheel suspension would be obtained. Said carriage portion could for
instance have the character of an arm resiliently pivotable in a vertical plane.
It is evident that numerous modifications of the designs described
are possible within the scope of the inventive concept.