IE72216B1 - Calving jacks - Google Patents

Abstract

In a calving jack, a frame 501 for juxtaposition against the hindquarters of a cow consists of a folding longitudinal member, at one end of which there is located a transverse member 502. Folding side members 503 are hinged at the ends of the transverse member 502, so that they may be moved from a disposition of use in which they extend alongside the rear of the body of the cow and a folded transport disposition in which they overlie the transverse member 502. A belt 505 links the free ends of the transverse members 503 to support the jack on the rear part of the cow's body. The longitudinal member 501 is suitable hinged intermediately at 515 so that the entire device may be folded into a compact storage and transport configuration. The jack may be manually operated, or alternatively, the end portion 514 of longitudinal member 501 may house a drive motor serving to wind-up a cable or chain 532 on a winch drum 543. Chain 532 carries a hook 509 for connection to ropes engaged around the calf during use of the device. The unit is preferably equipped with a pulling force gauge 544, which may be associated with a cut-out feature, to terminate the application of pulling force when this exceeds a preset value.

Description

Calving .jacks*' This invention relates to calving jacks. Calving jacks are used to assist the delivery of calves when cows are giving birth.

In the past, cows normally calved without any mechanical aid 5 and this is still the case on more primitive farms today. The disadvantage of leaving matters largely to nature is that there can be a high mortality rate of both calves and cows. This is particularly the case where relatively large calves are born to small cows.

Where calving is presenting difficulties, crude assistance may 10 be given by pulling the calf with ropes using bodily strength only.

In some instances, farmers have used tractors to pull calves. Several hundredweights of force may be required to draw out a calf, depending on the degree of lubrication available naturally.

Calving aids in the form of calving jacks are known and enable 15 an even pull to be applied in a substantially uniform manner under 7221 6 - 2 manual control, the manual effort being amplified by the mechanism of the jack. However, at least some such jacks still require the services of two operators in order to hold the jack in position and exert the required force.

It Is an object of the present invention to provide a calving jack which will be readily usable by a single operator and which will provide for application of an appropriate level of force to the calf, without placing any physical strain on the operator of the jack. It is a further objective of the invention to provide a calving jack capable of being transformed into a compact package for easy transport to a point of use. It is yet another objective of the invention to provide a calving jack conforming as far as possible to natural calving, so that the calf is withdrawn in a manner substantially equating to natural birth.

The present invention is further directed to the provision of a motor-driven calving jack of neat and versatile configuration,, easy to use and compact in storage for convenience in transport.

According to the invention, there is provided a calving jack having a frame for juxtaposition against the hindquarters of a cow, pulling means for connection to a calf to be withdrawn from the cow, motorised drive means for applying a pulling force to said pulling means, load detector means for monitoring the pulling force applied to said pulling means during use of the jack, and switch means actuatable by said load detector means to terminate operation of said drive asans when the pulling force exceeds a predetermined value, thereby terminating application of pulling force to the pulling means.

Said frame may comprise at least one longitudinal member at one end of which there are provided two lateral members, each lateral member being placeable in a disposition adjacent to the body of the cow during use of the jack. Suitably, each said lateral member is hinged at an opposite end of a transverse member provided at said one end of - 3 said at least one longitudinal member, for displacement between said disposition adjacent to the body of a cow and a folded inoperative disposition in which the lateral member is substantially parallel to and in juxtaposition against said transverse member. Preferably, the frame has two longitudinal members bridged by said transverse member at said one end. The free ends of said lateral'members are preferably linked by a flexible member, such as a belt. The belt is preferably separable at an intermediate point by suitable connecting means, for convenience of use when placing the jack in position on a cow.

W Said at least one longitudinal member may be displaceable between a storage or transport disposition of reduced longitudinal extent and an extended disposition representing an operating configuration of use. Said at least one longitudinal member is preferably hinged between its ends for pivoting or folding displacement between its storage or transport disposition and its extended disposition of use. The calving jack according to the invention may then comprise latch means for Maintaining said at least one longitudinal member in said extended disposition, so that a displacement movement from the storage disposition to bring the frame into its extended disposition of use terminates with the hinging mechanism automatically entering into a locked condition, in which it remains until released therefrom by positive action on the part of the user.

The jack according to the invention suitably also comprises control equipment for said drive means, said drive means and control equipment being accommodated within a portion of said longitudinal member. Where said longitudinal member is hinged, said drive means and control equipment are housed within said longitudinal member to one side of its point of hinging. in a favoured arrangement, said drive means comprises an electrically powered winch. Said load detector means may comprise means for adjusting said predetermined value of the pulling force, and - 4 may also comprise means for displaying the magnitude of the pulling force during use of·the jack.

The jack of the invention may also comprise braking means for controllably preventing reverse displacement of said pulling means on cessation of the application of pulling force to the pulling means In an especially favoured embodiment of the invention, said pulling means comprises a flexible chain or cable.

The frame of the jack of the invention may have a leading or cow-engaging portion shaped to substantially conform to the profile of the cow's body in its rearmost region. The rear or trailing end of the frame may incorporate a foldable stand portion to support said rear end of the device in use. Preferably the frame is foldable or otherwise transformable so that the unit may take up an especially compact configuration in a folded or transport condition thereof. In an alternative embodiment, the jack may comprise a leading portion for juxtaposition against the hindquarters of a cow and a rear portion which is displaceable towards and away from the leading portion by means of a drive mechanism, said rear portion having means for connection to a calf so that a pulling force may be applied to the calf during relative expanding displacement of said leading and rear portions.

Said cut-out or switch means for terminating drive when the pulling force exceeds a predetermined value may be provided, by a mechanical load detector operating to interrupt the electrical supply to an electric motor of the drive when the pull reaches said predetermined value. The mechanical load detector may also define the means for displaying the actual pull on the flexible cable or other pulling means at all times during operation of the device, as well as incorporating the means for setting a pulling force limit to establish said predetermined cut-out value of this force. Said limit may be set in dependence on the weight of the cow and the breed of the calf, and - 5 the mechanical load detector may have a suitable scale for this purpose.

The braking means may apply a stopping force to the shaft of the electric motor of the drive means on the cessation of electrical feed to the motor. Said braking means may be held inoperative by solenoid means during motor operation, interruption of the motor supply also de-energizing the solenoid, so that the brake is applied. Preferably the brake is applied through a freewheel mechanism, so as to restrain further forward or winding action of the drive means which would reapply pulling force to the cable, but to still allow reverse movement of the motor shaft for release of, or reduction in, cable tension.

A particular advantage of the calving jack according to the invention as powered electrically is that power may be supplied either from the mains or from a battery, and either an a.c. supply or a d.c. supply may be used. The jack may be manufactured in a multiplicity of different configurations, at least some of which allow for it to be transformable into an especially compact arrangement for easy transport. The calving jack of the invention may also be adapted to particularly suit the contours of the animal's body, so that it will remain in position during use with a minimum of effort and facilitate calving in a manner close to natural birth.

In an especially advantageous construction of the calving jack of the invention, said frame is adjustably extensible, preferably by means of lockingly interconnectible, telescopically associated, longitudinal members.

In a favoured arrangement, the frame also incorporates means for preventing overloading of the mechanical load detector, most suitably by means of a stop member for limiting the displacement of spring means of the load detector. Said stop member may be a substantially rigid transverse member of said frame. - 6 Where the leading or cow-engaging portion of the frame is adjustable between an operating disposition and a transport or storage disposition, locking means may be provided for latching said portion in one or other of said dispositions.

Control means for regulating the speed of the winch motor may include a governor for the motor, for example, a mechanical governor of the centrifugal weight kind. Arrangements may also be provided for direct mechanical interruption of the pulling force, without necessarily switching the electrical supply.

A guide and/or braking unit for the flexible chain or cable may consist of a guide passage through which the cable passes in use of the invention, and within which a braking member is urged against the cable to apply a frictional or braking force to it. The braking member may be displaceably urgeable against the cable by pivoting movement in a sidewise direction relative to the elongate direction of the cable. The entire guide/braking unit may also itself be displaceable, such as by pivoting displacement against the resistance of a spring force, for possible cooperation with trip-switch means, to cut out motor drive in the event of an over-run condition during use of the jack, i.e. excessive wind-up of the pulling cable. in a favoured arrangement of the invention, a portion of said longitudinal member within which a motor and control equipment are housed may also be provided with preferably laterally mounted handles for convenience of manipulation by a user. The electrically powered drive means in the form of a motor-driven winch, housed within said portion of the longitudinal member and activated in use by the user by means of a switch mechanism, this latter being preferably located at one end of a wander lead, applies a pulling force to the flexible chain cable or belt of the pulling means.

Embodiments of the invention, together with certain variations thereon, will now be described, having regard to the accompanying drawings, in which; - 7 Figure I is a diagrammatic pictorial view of an embodiment of calving jack motorised according to the invention.

Figure IA shows a framework variation in the embodiment of Figure 1, with Figure 2 is a pictorial view of an arrangement for association the jack of Figure 1, in which the working mechanism of the - 8 configuration of Figure 1 is enclosed in a separate container connected to the jack structure by a flexible cable, Figure 3 is a pictorial view of an especially compact configuration of motorised calving jack in a folded or transport configuration, Figure 3A shows the jack of Figure 3 in an expanded disposition, Figure 4 is a schematic pictorial view of a calving jack according to the invention in which a predetermined value of pulling force is established and controlled, Figure 4A shows a rack and pinion mechanism for substitution in place of certain features of Figure 4, Figure 5 shows a detail view of the force detection and setting feature of the arrangement of Figure 4, Figure 6 illustrates a variant on the arrangement of Figure 4, Figures 78 and 9 show a number of arrangements by which an alternating pull may be established on two ropes, extending side by side from the calving jack to the calf, Figure 10 is a pictorial view of a calving jack according to 20 the present invention, Figure 11 is a diagrammatic sectional view of a centrifugal governor for controlling the speed of the winch motor of a calving jack according to the present invention, - 9 Figure 12 shows a first embodiment of mechanical cut-out means Figure 13 shows a further mechanical cut-out arrangement, Figure 14 is a pictorial representation of the front end of another construction of jack according to the invention, for application to the hind-quarters of a cow, Figure 15 is a detail pictorial view of the hinging arrangement for the lateral members of the jack of Figure 14, Figure 16 shows the front end arrangement of the jack of Figure 14 in a folded disposition, Figure 17 is a side view of the longitudinal frame members of the jack of Figure 14 in a folded condition.

Figure 18 is a pictorial representation of a latching hinge member for use in the folding arrangement of Figure 17,, Figure 19 is a side view of the hinging member of Figure 18, Figure 20 is a schematic pictorial view showing the location of a guide/braking unit in a motor driven calving jack according to th« invention, Figure 21 is a schematic end view of the guide/braking unit o Figure 20, showing its mode of operation, θ Figure 22 is a pictorial representation of yet another embodiment of calving jack according to the invention, for application to the hind-quarters of a cow, and Figure 23 is a representation of a flexible rope arrangement for connection between the hook of the jack and the legs of a calf.

As shown in Figure 1, a motorised calving jack consists of an elongate frame 1, one end of which is engaged against the tail end of a cow, the position of which is denoted in diagrammatic form only by reference 2- The end of frame 1 which engages the cow is shaped to define a generally circular or rounded framework portion 3, which sits over the upper regions of the cow's hindquarters. In use, the end framework portion 3 is supported on the cow, which is in a standing position, while the other end of the frame 1 is supported by a stand or support portion 4, the upper end of which is hinged to frame 1 and the lower end region of which is provided with a foot bar 5, on which the operator may place his foot during use of the device. Frame 1 is further defined by spaced apart longitudinal members 6, which are hinged midway along their length as indicated by references 7, and are bridged at the leading or cow end by the rounded or circular framework portion 3. Further transverse members 8 and 9 bridge the space between the spaced apart longitudinal members 5. in the region of the rear end of the frame, where stand 4 is hinged to it.

A winch 11 is mounted by means of bolts 15 on the leading transverse member 8, from which winch a. cable ar chain 12 extends forwardly to the cow-engaging end 3 of the frame, terminating at a hook 13. An electric motor 14 drives the winch 11 and is mounted on the rear transverse member 9 by means of further bolts 15. Suitable switch means are provided for driving the motor, which may be connected either to the mains or to a suitable battery supply. The rearmost portion of the frame 1, to the rear of transverse member 9 and motor 14, is curved around so that a handle portion 16 is defined extending across the jack between the rear ends of the longitudinals 6. Handle portion 16 may carry a push button switch 17 for controlling the electric motor 14.

Operation of the calving jack of Figure 1 is as follows.

The ropes are fastened to the two front legs of the calf. Framework portion 3 is placed on the cow's hindquarters and back, and the longitudinals 6 defining the remainder of the frame 1 are aligned with the cow. Stand 4 is swung downwardly, pivoting about its hinges, so that the rear end of the frame is supported -thereon. The tie ropes are then connected to hook 13 of the jack Handle 15 is gripped by the operator using one hand and the foot is placed on the bar 5 of stand 4, in order to hold it Fixed in position and stabilize the entire unit. The cable is then wound in by activating motor 14 using the switch means push button 17. The cable then commences to pull the calf from the cow. Pulling continues until the calf's head emerges from the cow, at which time a short period of rest is provided before pulling is recommenced and the remainder of the calf is withdrawn. A suitable value for the pulling force established by the winch is approximately 254 Kg (five hundredweights), while the speed of pulling may be about 150 mm (six inches) per second.

Figure IA shows a modification of the framework arrangement of Figure 1, in which hinges 7 are replaced by locking e,mits 7a and each longitudinal 6 consists of a larger diameter rear section 6a, within which a lesser diameter leading section 5b is slidingly displaceable. The exact extended length of each longitudinal may thus be controlled, while a neat and compact contracted configuration of the jack is also provided.

Users may in certain circumstances favour use of the jack without lowering the legs 4. In order to facilitate such use, a gap may be provided in the region 3 of the framework to allow easy entry of the cable or rope 12, when placing the jack in position.

In the variation of Figure 2, the working mechanism of the jack of Figure 1, including the winch and its motor, is encased in a container 21, and this container communicates with the jack structure proper through a bowden cable type arrangement, in which the pulling cable 12 passes through and within a sleeve 22. weight of the winch and motor to be removed to a the jack structure itself, so that the weight to cow and stabilized by the user may be reduced.

This enables the location remote from be supported by the Figure 3 shows a compact arrangement of the jack of Figure 1 in a folded configuration, in which it packs into a case unit for ready transport by veterinary surgeons or other users to a point of use.

In this compact configuration, the folded jack of Figure 1 is received within a container 31. The handle portion 16 of the jack, carrying switch 17, may be noted extending from one end face of the container, while hook 13 is carried on its exterior.

This variation of the invention may also itself represent a further embodiment of calving jack, in which the container or case 31 is itself mechanically expansible under control of electrical means through switch 17. In this case, container portion 32 is placed against the cows hindquarters, and the calve's legs are attached to the unit via hook 13. Activation of the device causes portion 33 to be displaced rearwardly relative to portion 32 Into the active disposition shown in Figure 3Ae either by hydraulic power or by a screw thread mechanism contained In expanding member 34, thus drawing the calf out, as hook 13 travels with portion 33, to which it may be connected by cable 12. Longitudinal displacement is guided by and takes place along sliding guide members 35. Portion 32 may be profiled for comfortable engagement with the cow's hindquarters.

Mechanical retraction of the device into its compact configuration may be brought about by reversing the action, again under electrical control. A variety of further alternative arrangements may also be provided.

The embodiment shown in Figures 4 and 5 enables the actual pulling force to be monitored and also provides for pulling to be terminated when the pulling force exceeds a predetermined value. As shown in Figure 4, the longitudinals 6 of the frame terminate in curved handle 16. which carries push button switch 17, but in place of the rigid transverse winch and motor mounting members 8 and 9 of the first construction, a single rigid transversal 41 extends across the frame immediately forwardly of the handle 16. The winch and motor are mounted on respective transverse leaf spring members 43 and 44, these spring members being in turn secured at their lateral ends to lugs 42 located on the inner sides of the longitudinal members 6 by means of bolts 45. Winch 11 is mounted on leaf 43 and motor 14 is secured to leaf 44 by bolts 15. Cable 12 extends forwardly from winch 11 towards the forward end of the jack. The winch and motor unit together with the leaf springs 43 and 44 define a resiliently mounted drive assembly capable of limited displacement in the axial direction of the apparatus, forward movement towards the cow under the influence of the pulling force being resisted by flexure of the springs 43 and 44.

The pulling force is indicated by the mechanical detector now to be described, which also includes a calibrating feature for setting a desired level of force and a cut-out arrangement for terminating pulling when the actual pulling force exceeds the pre-set figure. Considering now figures 4 and 5 together, the detector unit has a gauge faceplate 46, secured to the drive assembly as a whole by bolts 56. A pull indicating hand 47 is pivoted about an axis 48 and has a cranked arm portion 49 extending on the opposite side of the pivot point 48 from the hand 47, the end region of the cranked arm abutting against a lug 51. extending forwardly from the rigid transversal member 41. Biassing means such as a coil spring may be provided to ensure continuing abutment of arm 59 and lug 51. According as the drive assembly moves axially forward under increasing pulling force, hand 47 will be enabled to pivot to the right in a clockwise direction, as shown in figures 4 and 5, and a measure of the actual pulling force is provided by the figures set out along the force scale 59.

A setting or gauge hand 52 is also provided, pivoting about the same axis 48 as the force hand, and carrying an electrical switch 53. The gauge hand is set to point to a value representative of the cow's weight, as set out on scale 61 of the gauge face plate, and when the actual pulling force reaches a value representing a maximum for a cow of the particular weight in question, force hand 47 will abut against switch 53 so as to terminate supply of electricity to the motor and bring about a cessation of pulling action without moving the gauge hand 52. A handle 54 facilitates setting the gauge pointer to the correct value. Cable 55 provides the electrical feed to and from the switch 53, while a bulb 57 may be located to facilitate use of the apparatus at night. A stop 58 limits overall combined movement of the two hands, should the force hand engage the switch and impel the setting hand beyond its preset value. Restraint on scales movement thus serves to prevent over-stressing of any component of the mechanism.

Operation of this embodiment of the invention is as follows.

The gauge hand 52 is set to a value corresponding to the weight of the cow. The calf is connected to the jack as before and pulling is initiated by depressing switch 17. The electrical feed to the motor 14 takes place through cuc out switch 53, whereupon winch 11 is driven to pull cable 12 and start withdrawing the calf from the cow. As the pulling force increases, the leaf springs 43 and 44 will bend or flex to some degree, and the drive assembly will advance axially a short distance in the forward direction as indicated by arrow 62.

Accordingly cranked arm 49 and force hand 47 are permitted to pivot in a clockwise direction. If the calf is reasonably easy to pull, it may be withdrawn fully from the cow without the pulling force reaching any excessive value, which would cause hand 47 to impinge against switch 53 and terminate motor drive and, therefore, pulling action. If the pulling force exceeds a value representing a safe maximum for the particular weight of the cow, then hand 47 will engage against switch 53, the motor will cut out, and the farmer or other user will be made aware, by the cessation of pulling, that the calf cannot be removed in this manner and that the services of a veterinary surgeon will be necessary in order to deliver the calf safely, Following cut-out, the device may be reset by advancing the setting hand 52 manually, using the handle, until switch 53 engages against stop 58. This resets the switch, and the setting hand may then be moved back to the weight setting appropriate to the cow. The setting hand is most suitably set to operate at a pull corresponding to the calf’s head having been advanced to a certain point not precluding removal of the calf from the cow by surgery, should the pull at that point exceed a safe level. Alternatively, if the device has not shut off when the calf's head has reached this point, the drive may be stopped manually, and the setting hand moved clockwise to a higher pull setting, so that pulling is not inadvertently terminated subsequently, assuming that it is found safe to continue withdrawal of the calf beyond this critical head location.

The settings on the gauge face plate 46 may be established by suitable experts for all standard breeds of cows. Maximum safe pulling forces may be worked out for each breed and size of animal and the gauge calibrated accordingly. This arrangement represents an especial advantage for farmers in that they may set the device up for minimum loss of calves. The gauge face plate may be interchangeable to facilitate use of the device for different breeds. In each case, the scale hand is set according to the weight of the cow and the breed of the calf to be removed from the cow, the shape of the calf varying significantly from one breed to another. Minch speed may also be selected for optimum withdrawal of calves, A spring means may be interposed between the cable and hook, or elsewhere in the pulling line, so as to provide a degree of resilience at the initiation of pulling.

The rack and pinion arrangement shown in Figure 4A depicts an alternative means for bringing about rotation of the setting hand of - 16 the gauge by virtue of axial movement of the drive assembly and may take the place of the crank arm 49 in the mechanism of figure 4. figure 6 shows an alternative embodiment of the invention, generally similar to that of Figure 4, but with certain added features for additional accuracy and precision in operation. A drive wheel 71 is located at the end of the motor shaft and has, mounted on it, a concentric freewheel 72, The plunger of a solenoid switch 73 carries a brake shoe 74, which bears against the periphery of freewheel 72 when the solenoid id deenergized. Energization of the solenoid through contacts 75 withdraws the brake shoe from freewheel 72, against the braking spring 75.

In operation of this arrangement of the device, when power is cut off to the motor, the brake shoe 74 is applied and the drive is stopped substantially instantaneously. The freewheel enables the motor to run backwards and unwind the cable wound up on the winch, even though the brake is applied.

Numerous variations in the detailed structure and operation of this braking system are possible. The brake may engage against an interior surface of a wheel or onto a braking disc. In regard to the gauging device, the cut-out switch may be located on the indicating hand instead of the setting hand. Also, different switching arrangements may be provided. Rack and pinion drive of the gauge indicating hand is again also possible, as previously shown in Figure 4A.

In either of the arrangements described in regard to Figures 4 and 6, the springs 43 and 44 on which the winch and motor are mounted may be rectangular in shape and mounted directly on the frame by bolts at each end of the spring, spacers being interposed between the respective spring member and the frame member to give the required spring action at low cost. The bolts may also be sleeved, the sleeves extending to the frame portion surface, so that the bolts may be tightened while nonetheless establishing the necessary spring action.

The calving jack of the invention may also be adapted to provide for an alternating pull on two side-by-side cables, where attachment of the cables is made separately to two of the legs of the calf. As shown in Figure 7, two cables 86 are wound up over adjacent pulleys 84 onto winch drum 88. Each pulley is mounted at the end of a rocker arm 82, which is itself mounted for pivoting movement on a shaft 87. Pivoting movement is induced by cam plates 81 located one at each axial end of the winch drum 88, each of which engages a respective cam follower on one of arms 82. Thus the rate of wind-up of each cable is alternately increased and decreased for a constant rate of wind-up on the winch drum.

A similar result may be achieved by winding up the cables on a winch drum of crankshaft form, such as is illustrated in Figure 8 by reference 91, or by winding them up on winding plates, as denoted by reference 95 in Figure 9.

As shown in Figure 10, a modified calving jack in accordance with the present invention is provided with elongate frame members 101 and 102, each of which is made up of three telescopically displaceable portions 101a, 101b and 101c, and 102a, 102b and 102c. Each portion of each of these members is of generally box-shaped cross-section. Portions 101c and 102c are each slidingly displaceable within and relative to portions 101b and 102b. Similarly, portions 101b and 102b slide relative to portions 101a and 102a. On each portion which receives a portion of lesser size within it in a telescoped condition, a respective locking member 103 is provided, for holding the telescopically received smaller-sized member portion in a predetermined position relative to the larger-sized outer or receiving portion.

Each locking member 103 has a plunger 104 displaceable substantially perpendicularly to the elongate direction of members 101 and 102. - 18 Each plunger 104 slides within a sleeve 105, and the plunger is urged towards the smaller section member portion received within the outer portion by means of a coil spring surrounding the plunger and retained within sleeve 105 by an apertured end cap 106, through the central opening of which plunger 104 passes axially. Preferably the inner end of each plunger, i.e. that which serves for effecting the locking function as described hereinafter, is also enlarged to provide a seating for the coil spring.

Each of the member portions 101b and 101c and 102b and 102c received within a larger-sized portion is provided with a plurality of locating or locking holes 107, distributed along its axial length, and each hole 107 is of a size such as to receive the operating or locking inner end of a plunger 104. In this way the members 101 and 102 may be adjusted telescopically to a desired length, and then held locked at that length by engagement of plungers 104 in appropriately selected ones of the locking or locating holes 107.

According to this variant of the present invention, the load detector unit has front and rear leaf spring members 10Q and 111 separated and spaced apart by spring unit side members 115. Thus the spring unit is an entirely self-contained entity, and the arrangement differs from that described in regard to Figures 4 and 6 in that the leaf members are not mounted directly on the elongate side members of the frame. Rather the load detector unit as a whole is mounted relative to the side members by means of spring unit holders 112, which are secured to the spring unit side members 115 by bolts 114, through the intermediary of spacers 113.

This arrangement provides the particular advantage that a stop member for spring displacement may be provided in the form of transverse rigid stop member 116, which extends across the width of the unit between the largest section portions 101a and 102c of the longitudinal side members. When the load detector unit responds to the existence of an axial winch load by deflection of springs 109 and 111, the maximum displacement of these spring members is limited by engagement of spring 109 against transverse stop member 115, A further advantageous variant in the present invention is provided at the leading end of the unit, where ring bar 117 engages against the hindquarters of the cow. Ring bar 11/ may consist of a continuous substantially semicircular member, or it may be divided by means of a slit or gap indicated by the dotted lines referenced 118, in which case the ring bar is essentially made up of two separate quarter circle portions. In either event, the bar is preferably pivotingly displaceable between operating and storage configurations by rotation about a hinge axis defined by pins 119 mounted in hinge lugs 121 at the leading ends of longitudinal members 101 and 102. The ring bar, whether a single unit or divided into quadrant portions, is preferably retained in either its operating disposition or in a storage configuration by latching members, not shown, engaging in notches 122 appropriately disposed about the peripheries of the hinge lugs 121.

Curved rigid bar 123 extending between the longitudinal members at the leading ends thereof provides a further feature for locating the jack of the invention against a cow's hindquarters.

A further difference between the present invention as shown in Figure 10 and the arrangements previously described relates to the location of the operating push-button, which in the present arrangement is located towards the leading end of large size longitudinal member portion 102a. The entire operating mechanism may also be suitably encased, with the operating button being located for convenience of use on the exterior of the case.

It is also preferred in the calving jack according to the invention, that the speed of the winch motor be controlled to run at a suitable rate appropriate to the pulling circumstances, A mechanical - 20 governor using centrifugal weights is shown in Figure 11. Rotary shaft 131 extends from the winch electric motor and has mounted thereon a tightly fitted sleeve 132. Arms 133 and 134 extend generally radially outward from sleeve 132 and weights 135 and 135 are mounted pivotably on these arms at hinging points 137 and 138. An axially displaceable sleeve 139 is slideable relative to rotating shaft 131 under the action of weights 135 and 135, to engage against a hingeable arm 140 through a friction pad or bearing 142. Arm 140 pivots about a hinge point 141. At the other end of pivotal arm 140, a pull rod 143 is connected at pivot pin 144. Arm 140 carries one (145) of a pair of make and break contact points, the other (150) of which is mounted fixedly relative to the other components of the governor on a member 145. Rod 143 is siidingly displaceable relative to the mounting member 145 for the second contact 150, and a coil spring 147 acts to urge the contacts into a make condition by rotation of arm 140 towards the left, as shown in Figure 11. An adjustable nut 148 enables the making urging force to be adjusted.

When the motor is switched on, current flows through the contact points 145, 150 to the motor control switch. When the motor reaches a predetermined speed, the outward displacement of rotating weights 135 and 135 will cause axial displacement of sleeve 139 in the direction to rotate arm 140 to the right, as shown in Figure 11, and thereby break the contact between points 145 and 150. The motor will then immediately start to slow, the weights 135 and 135 will again move inwardly, and contact will be restored. This making and breaking of the electrical contacts will occur several times per second, and the motor will run at a substantially steady speed.

The invention may also provide an arrangement enabling pulling pressure to be switched off mechanically, without necessarily interrupting the electrical supply to the motor. A first embodiment of such an arrangement, for association with the gauge construction previously described in regard to Figures 4, 5 and 5, is shown in - 21 Figure 12. This particular configuration of mechanical cut-out requires a clutch to be provided in the drive chain.

Spring scale hand 201 and gauge setting hand 202 share a common pivot axis. Clutch release rod 206 is connected with a clutch in the drive chain. The gauge hand 202 is kinematically connected with the clutch release rod 206 by means of a linkage including a rotatable rod 203 mounted on gauge hand 202 by means of sleeves 214 and 215. Rod 203 is restrained against axial displacement, but can rotate about its longitudinal axis. At the end of rod 203 in the region of the free end of hand 202, a curved-around or hooked portion 212 is provided on the rod, defining its end region, and terminating at a contact point, located substantially beneath the gauge hand 202, spring scale hand 201 coming into contact with end region 216 of rod 203 when the scale hand 201 comes into alignment with the setting hand 202. In these circumstances therefore, the continued exertion of pulling pressure causes rod 203 to rotate about its axis.

The other end of rod 203 terminates in a cranked or right-angle portion 213, which is pivotably linked at point 209 with a connection rod 204. The other end of connection rod 204 is in turn pivotably linked at 210 to a bell crank 205, the bell crank being pivoted on fixed members 211. The bell crank 205 has a free end region 207, defining a hook for interconnection with a corresponding hook end portion 208 of the clutch release rod 206. When the hooked ends 207 and 208 are interengaged, clutch release rod 206 is maintained in the disposition in which the clutch and drive are engaged.

Operation of the arangement described above will be clear from the drawings. Contact of hand 201 with end 216 of rod 203 causes rotation towards the left, as shown in Figure 12, of the cranked end region 213 of rod 203. The linkage 204 and 205 is in turn displaced, so that hook end 207 becomes disconnected from rod 208. Stop 217 ensures that disconnection inevitably occurs under these circumstances. - 22 Alternative arangements in substitution for the right-angle portion 213 may also be provided, including, for example, a separately hinged member, or involving the use of a universal joint. in the alternative arrangement shown in Figure 13, the mechanical cut-off device is interposed between the ropes connected to the calf and the pulling wire of the jack. The ropes coming from the calf are connected to loop or ring 308. A wire cable 302 extending from the cut-off device is connected to the pulling means of the jack. Cable 302 exerts a pressure on spring 301 when pulling pressure is applied. The cut-out device is coupled to ring 308 by means of a hook 304. The hook is linked with pulling cable 302 through a kinematic mechanism consisting of a stay bar 303, pivoted to cable 302 at point 307 and pivoted to hook 304 and a transverse bar 305 at point 305. The opposite end of transverse bar 305 from that pivoted to stay bar 303 is pivoted, at point 309, to the opposite end of spring 301 from that coupled to cable 302.

According as pulling pressure is increased, the linkage results in hook 304 rotating clockwise. if the pulling pressure exceeds a predetermined value, hook 304 will move out of interconnection with ring 308 and pulling is then terminated. Under these circumstances, the vet should be brought in.

An adjusting arrangement facilitating variation of the predetermined pulling force release point can be provided on stay bar 303, for example, by bar 303 consisting of two telescopic slideablv interconnected portions, inner portion 312 being a notched bar, and the other outer tubular portion 313 being provided with a spring-loaded plunger 311 for engagement in a selected aligned one of a plurality of notches 310 in bar 312. The notched stay bar 303 may be suitably calibrated to accommodate a variety of cow and calf weight combinations.

As shown in Figure 14, a calving jack according to a further - 23 embodiment of the invention has two longitudinal frame members 401, bridged at a front or leading end by a transverse member 402. At each end of transverse member 402, a lateral member 403 is hinged, indicated by reference 404. A belt 405 extends between the free ends of the hinging lateral members 403, and is provided, with a central clip means 406, for ready assembly in use. This front end region of the frame is applied to the hindquarters of a cow, with transverse member 402 abutting close to the cow's rear and lateral members 403 lying one to each side of the cow's rear body portion. The device is supported on the cow's hindquarters by means of the belt 405, which is snapped together by means of clip 406 to overlie the upper part of the cow's body.

As shown in Figure 14, the jack has a central drive rod 407 on which there is located a drive mechanism 408 with a hook 409 for engaging ropes or other means to be connected to a calf to be pulled. Rearward movement of the drive mechanism 408 produces the pulling force. A winch and an electric motor for the winch may alternatively be mounted at the other or rear end of the frame structure.

Figure 15 shows detail of the hinging arrangement between the righthand lateral member 403 of Figure 14 and the righthand end of transverse member 402. The hinge 404 is defined by hinge plates 411 welded to the upper and lower edges of lateral member 403 and extending sidewise from it to embrace in a forked manner the righthand free end of transverse member 402. A hinge pivot pin 412 extends through the forked hinge plates 411 and the body of the end of transverse member 402, to define the hinge axis. - 24 The hinge plates 411 and the location of the hinge pivot 412 are selected so that the lateral members may be folded across the front transverse face of member 402 in a compact manner, to transform the unit into a storage disposition. This folded configuration is illustrated in Figure 16, with the lefthand lateral member lying in close juxtaposition to the longitudinal outward or front face of transverse member 402 and itself overlaid at a short further outward spacing by the righthand lateral member. Belt 405 is shown lying forwardly of the folded lateral members, but can in practice be looped around them in a compact and convenient manner.

Transformation of the calving jack frame according to the present invention into a compact storage configuration is further facilitated by the features shown in Figures 17, 18 and 19. As shown in Figure 17, each longitudinal side member 401 consists of a front portion 413 and a rear portion 414 hinged together by hinge member 415. Front portion 413 can therefore be folded rearwardlv and upwardly through approximately 180° into a disposition in which it overlies rear portion 414, occupying a relatively small volume of space and reducing the overall length of the unit by approximately one-half. In this folded configuration, the calving jack of the invention is typically capable of being accommodated within the boot or trunk of a car. It is thus especially useful to a veterinary surgeon, in that it does not require any special type of vehicle for its transport from location to location.

A suitable hinge member 415 is illustrated in more detail in Figures 18 and 19. It consists of a front part 416 and a rear part 417, each of which is ’'elded or otherwise affixed to the respective portion 413 or 414 of the longitudinal member 401. Longitudinal member 401 is suitably of box section, to reduce the weight of the jack according to the invention to the greatest extent possible. In upper regions of the front part 416 and rear part 417 of hinged member 415, intermeshing sets of front 418 and rear 419 lugs extend towards and - 25 between one another and are coupled together for hinging movement about a pivot pin or otherwise defined pivot axis 421, This intermeshing for pivotal displacement by means of upstanding lugs facilitates convenient relative rotation of the parts 416 and 417 of the hinge member of the invention through 180°, to transform the frame into its folded disposition.

A latch pin 422 is displaceably mounted within the body of front part 416 in a bore extending between the upper and lower surfaces of this part in its disposition of use. Spring means within the body of part 416 urge latch pin 422 downwardly, so that its lower end extends outwardly relative to the lower face of longitudinal member portion 413, in the operating disposition of this portion. The lower face of latch pin 422 is provided with a bevelled profile, indicated by reference 423, the direction of this bevelling being such that as the hinge swings into its operating configuration, the bevelled edge 423 comes to bear against a base portion 424 of rear part 417 of the hinge on a upper face of this base portion, so that the latch pin 422 is urged upwardly against the spring force within the body of front part 416. As the hinge member approaches its fully rotated position corresponding to the disposition of use of the frame member portions, latch pin 422 comes into alignment with a receiving aperture 425 in a base portion 424 of the generally L-shaped rear part 417 of hinge member 415. On full alignment of the latch pin axis with aperture 425, latch pin 422 springs into engagement within aperture 425, thereby locking the two hinge parts together in a disposition of use. A manually operated latch release handle 426 projects upwardly from the upper surface of hinge part 416, so that the latch may be released by the user against the force of the spring, when the apparatus is required to be dismantled again for removal. The latching arrangement however ensures automatic engagement of the hinge parts during an assembly operation, without any risk of their becoming separated, with resulting folding or collapsing of the apparatus during its use. - 26 Figures 20 and 21 show a further feature of the invention.

As shown in Figure 20, a motorised calving jack according to the invention has lateral longitudinal members 401 and rear transversals 427, 428 and 429, between the two latter of which a motor 431 is mounted. A cable 432 extends to a winch mechanism mounted within the motor housing 431 s or in the vicinity thereof, the representation of these Figures being schematic only. On the leading transversal 427, there is mounted a guide/brake unit 433. As further indicated in Figure 20, this guide/braking unit is provided with a cable guide groove 434, within which a braking member 435 is urged against the cable in a sidewise manner to exercise frictional or braking or restraining force on it. Brake member 435 suitably consists of a plate form portion, mounted for pivoting about an axis 436 parallel to the general direction of the cable, for urging against the cable in a sidewise manner by spring 437, to apply a force against the cable in the direction directed by arrow 438.

The entire guiding/braking unit 433 is itself mounted on transversal 427 for pivoting displacement in a rearward direction about a generally vertical pivot axis 439» The direction of possible pivoting displacement of guide/brake member 433 is indicated by arrow 441 and takes place against the resistance of a spring 442. The purpose of this mode of mounting of the guide/brake unit 433 is to provide for the cut-out of motor 431 drive, in the event of excessive wind-up of cable. In this event, the shackle connecting the wire rope to the ropes pulling the calf will be pulled towards the rear until it comes up against the front face of guide/brake unit 433, the shackle being too large to enter the groove 434. The entire unit then pivots rearwardly against the force of spring 442, and it is associated with a power cut-out switch for the motor, to trip the motor and cease motor drive in these conditions. This feature thus represents an important safety element in a motor driven jack according to the invention. - 27 The present embodiments of the invention accordingly provide an effective, readily foldable and compact construction of motorised calving jack. The novel hinging arrangement provided for the longitudinal members allow a quick release snap-fit during assembly of the device, so that its use in dark and dirty environments is facilitated, as compared with the assembly by means of screws passing through aligned holes, which may be difficult to accomplish under adverse conditions. The drive may be transmitted from the electric motor to the winch by a gearbox using spur gears, with reductions of the order of 2000 to 1 or greater. As an alternative to spur gears, worm or screw-type gears may be used, or any other form of motorisation giving a high degree of reduction and/or fine control of the cable take-up and drive speed.

As shown in Figure 22, a further embodiment of calving jack according to the invention has a single longitudinal frame member 501, at the leading end of which there is located a transverse member 502, extending symmetrically and substantially at right-angles to each side of the central longitudinal axis of «ember 501. At each end of transverse member 502, a lateral member 503 is hinged, the hinge mounting being indicated by reference 504. A belt 505 extends between the free ends of the hinging lateral members 503 and is provided with a central clip 505, for interconnecting the belt portions in use. An adjustable buckle 507 enables variation in the length of the belt.

This front end region of the calving jack is applied to the hind-quarters of a cow, with transverse member 502 abutting close to the cow’s rear and lateral members 503 lying one to each side of the cow's rear body portion. The device is supported on the cow's hindquarters by means of the belt 505, the two ends of which are snapped together using clip 506 to overlie the upper part of the cow's body, the length of the belt being adjusted using buckle 507 to match the size of the cow. - 28 The hinging arrangement 504 for the lateral members 503 is such that these members may be overlappingly folded across the front transverse face of member 502 in a compact manner, to transform the unit into a storage disposition. Transformation of the calving jack frame according to the present invention into a particularly compact storage configuration is further facilitated-by the single longitudinal member 501 consisting of a front portion 513 and a rear portion 514, these portions being hinged together by hinge member 515. Rear portion 514 can therefore be folded forwardly and upwardly through approximately 180° into a disposition into which it overlies front portion 513, the folded member portions 513 and 514 occupying a relatively small volume of space and reducing the overall length of the unit by approximately one-half. In this folded configuration, the calving jack of the invention is suitable for accommodation within the boot or trunk of a car. It is thus especially useful to a veterinary surgeon, in that it does not require any special type of vehicle for its transport from location to location.

The single hinge member 515 is suitably identical in construction with the hinge member 415 described in connection with the embodiment of Figures 14 to 15, in which the jack comprises two longitudinal members.

The calving jack of the invention in the present embodiment is most suitably motorised by an electric motor being housed within longitudinal member part 514 in the region indicated by reference 531 in Figure 22. This region is located a little to the rear of the hinge member 515 in the assembled configuration of longitudinal member 501. Also within the housing defined by member portion 514, a reaction spring is located in the region indicated by reference 542 for resilientlv constraining displacement of the motor within the housing defined by part 514 when the motor is exerting a pulling force during use. For exerting this pulling force, a winch reel 543 is mounted at the rear end of longitudinal member part 514, winch reel 543 being - 29 driven by motor 531 through an internally mounted gearbox and mounting a pulling cable 532 ending in a hook 509- A pulling force setting and monitoring meter 544 is located in an upper face portion of part 514, on which meter or clock the actual pulling force being exerted by motor 531 during use of the calving jack is shown and may be monitored visually, as well as which a maximum pulling force not be be exceeded in use of the invention may also be set, the motor tripping out if this pulling force is exceeded during use. For convenience of use, the two-way motor control switch 545 is preferably located at the end of a wander lead 546, so that the user may control operation of the jack while located, for example, at the cow end of the unit or to one or other side of it. Handles 547 are provided on the sides of rear part 514 approximately two-thirds way along its length from the hinge towards its rear end, so that the user may support this end of the apparatus during use. Other components including brake means and the like may also be accommodated within housing 514.

Use of the calving jack according to the invention is straightforward. The parts 513 and 514 of longitudinal member 501 are swung out into their extended disposition and are locked together in this orientation by latching hinge member 515. Lateral members 503 are then swung out and belt 505 is adjusted so that the leading end of the apparatus may be placed over the cow's hindquarters. The motor 531 is next activated using switch 545 to run out a sufficient length of cable 532 for hook 509 to be engaged with ropes for engaging the calf's legs. Figure 23 shows a suitable arrangement 548 of attachment ropes for connecting the hook 509 of the jack to the legs of a calf to be pulled. Preferably the motor is driven by batteries which may be housed within part 514 of longitudinal member 501, but the weight of the equipment may be reduced by having a separate supply to motor 531, either from a vehicle battery or from a mains supply. An appropriate maximum pulling force is then set on clock or monitoring means 544, and the jack is operated, using switch 545, to draw the calf from the cow. In the event of the actual pulling force, which is continually - 30 displayed on clock 544, exceeding the preset maximum pulling force, pulling is immediately suspended, thereby ensuring that damage is not inflicted on either the cow or the calf, while brake means ensure that the cable is held with the degree of extension already achieved, without cable runback.

Claims (12)

1. A calving jack having a frame for juxtaposition against the hindquarters of a cow, pulling means for connection to a calf to be withdrawn from the cow, motorised drive means for applying a pulling force to said pulling means, load detector means for monitoring the pulling force applied to said pulling means'during use of the jack, and switch means actuatable by said load detector means to terminate operation of said drive means when the pulling force exceeds a predetermined value, thereby terminating application of pulling force to the pulling means.

2. A calving jack according to Claim 1, wherein said frame comprises at least one longitudinal member at one end of which there are provided two lateral members, each lateral member being placeable in a disposition adjacent to the body of the cow during use of the jack.

3. A calving jack according to Claim 2 wherein each said lateral member is hinged at an opposite end of a transverse member provided at said one end of said at least one longitudinal member, for displacement between said disposition adjacent to the body of a cow and a folded inoperative disposition in which the lateral member is substantially parallel to and in juxtaposition against said transverse member.

4. A calving jack according to Claim 3, wherein the free ends of said lateral members are linked by a flexible member. 5. A calving jack according to any of Claims 2 to 4, wherein said at least one longitudinal member is displaceable between a storage or transport disposition of reduced longitudinal extent and an extended disposition representing an operating configuration of use.

5. A calving jack according to Claim 5, wherein said at least one longitudinal member is hinged between its ends for pivoting or folding displacement between its storage or transport disposition and its extended disposition of use. - 32 7. A calving jack according to Claim β, comprising latch means for maintaining said at least one longitudinal member in said extended disposition.

6. 8. A calving jack according to any of Claims 2 to 7, comprising control equipment for said drive means, said drive means and control equipment being accommodated within a portion of said longitudinal member.

7. 9. A calving jack according to any preceding claim, wherein said drive means comprises an electrically powered winch.

8. 10. A calving jack according to any preceding claim, wherein said load detector means comprises means for adjusting said predetermined value of the pulling force.

9. 11. A calving jack according to any preceding claim, wherein said load detector means comprises means for displaying the magnitude of the pulling force during use of the jack.

10. 12. A calving jack according to any preceding claim, comprising braking means for controllably preventing reverse displacement of said pulling means on cessation of the application of pulling force to the pulling means.

11. 13. A calving jack according to any preceding claim, wherein said pulling means comprises a flexible chain or cable.

12. 14. A calving jack substantially as described herein with reference to and as shown in any one or more of Figures 4 to 13 and 15 to 23 the accompanying drawings, or any one or more of these drawings as modified having regard to any one or more of Figures 1 to 3 and 14.