the invention will be described for three illustrative embodiments , in conjunction with the accompanying drawings , in which : fig1 is a front three - quarter perspective view of a first embodiment of the invention ; fig2 is another three - quarter perspective view of the device of fig1 as viewed from below ; fig3 is an enlarged fragmentary vertical sectional view taken at 3 -- 3 of fig2 ; fig4 is a view in side elevation of a second embodiment , with portions broken - away and in section to reveal internal detail ; and fig5 is a vertical sectional view to show a third embodiment . all three embodiments may be built into or upon a boot 10 having the general appearance depicted in fig1 . commercial hoof boots are available from various manufacturers , including barrier corporation , mineral wells , tex . ; they are commercially offered to protect and cushion conventionally shod hoofs for durability in rough - riding races over rough terrain . such boots are of one - piece molded vinyl construction and come in a range of sizes , to assure correct fit to the particular shod horse . however , in the context of the present invention , the conventional iron shoe is removed and is preferably replaced by an all - plastic shoe , for example to give stability to a fractured third phalanges bone to be treated . hoof - boot size should therefore be selected in the context of the afflicted hoof size when fitted with the plastic horseshoe . as shown , the commercial hoof boot 10 comprises a relatively stiff sole portion 11 integrally connected at its periphery with a relatively flexible upper portion 12 . the interior volume within the upper portion 12 will be understood to be suited for conformance to the particular hoof to be treated . the bottom of the sole portion 11 is characterized by an integrally formed downward projection 13 in the shape of the horse &# 39 ; s shoe , conventionally iron , but here understood to be preferably a plastic shoe to stabilize bone fragments . the integral projection 13 will be understood to fully register with the horse &# 39 ; s shoe , for optimum distribution of leg - bearing forces at ground contact . the region 14 within projection 13 is offset from ground contact . the profile of the upper portion 12 rises toward the backside 15 of boot 10 , and rear corners are slit , as at 16 , to define opposed side tabs 17 - 18 and a rear tab 19 for finger engagement , as an aid in applying the boot to the hoof . a belt 20 , threaded through spaced pairs of apertures in upper portion 12 , completes the commercially available boot , being provided with suitable means 21 at one end for releasably cinched circumferential belt retention of the upper portion 12 to hoof contour . in the form of fig1 to 3 , the horseshoe - shaped projection 13 has been routed along its median contour to define a channel of depth d and width w , to accommodate insertion of a multi - turn electrical coil 25 ; the depth d may suitably coincide with the recessed extent of the sole region 14 . the thus - inserted contour of coil 25 has been indicated by a heavy phantom course 25 &# 39 ; in fig2 leaving a rear segment of the coil exposed at the region 26 of sole 14 , between the spaced rear ends of the horseshoe shape of projection 13 . the coil 25 is so oriented in its insertion within the routed groove that coil leads 27 -- 27 &# 39 ; are available in the rear sole region 26 . coil placement is rendered into a permanent embedment by suitable potting 28 ( fig3 ) in the routed groove , and the potting material is preferably further applied over exposed coil and lead segments at the rear sole region . a generally prismatic signal - generator housing 30 is securely fastened to the back 15 of the upper portion 12 . housing 30 will be understood to contain a power source , such as a rechargeable battery and pulse - generator means , the latter being generally as described in said ryaby , et al . patent , and output of the pulse generator being directly connected to leads 27 -- 27 &# 39 ;. as shown , a removable plug 31 provides access for the output jack of conventional battery - charging means ( not shown ). also , as shown , an externally accessible push - button switch 32 enables an operator to switch the signal generator from inactive to active state , and vice versa , for intermittent periods of time , as for example , one or more two - hour treatment periods as may be prescribed for each day . further , as shown , a small indicator lamp 33 will be understood to be viewable at the top edge of housing 30 , to show to the operator whether the pulse generator is or is not in operation . to apply the boot of fig1 to 3 to an afflicted hoof , it is of course first necessary to remove the horse &# 39 ; s conventional iron shoe , preferably replacing the same with a magnetically transparent ( plastic ) shoe . the hoof is then inserted , and prompt and properly seated fit is aided by grasping one or more of the upper tab regions 17 - 18 - 19 . the belt 20 is then fastened behind back panel 15 . the modification of fig4 differs from that of fig1 to 3 , in that an additional multi - turn electrical coil 35 is mounted to the upper portion 12 , and its leads 36 -- 36 &# 39 ; are so connected to the output of signal generator means 30 as to be in flux - aiding relation to the concurrently excited lower coil 25 . such excitation connections to coils 25 - 35 may be in parallel , but their preferred series connection is schematically indicated . as shown , the upper coil 35 is a separate assembly , preferably an annular potted embedment of coil 35 in yieldable protective plastic , wherein the separate assembly integrally includes dependent flange formations as at tabs 37 - 38 , each of which may have a pair of slots for threaded reception of belt 20 . for simplicity , the alignment of belt 20 is shown only by phantom outline in fig4 and it will be understood that by having the slots of tabs 37 - 38 in substantial register with the slot pairs in upper portion 12 , a threading of belt 20 via registering slots will provide anchorage and support of the second coil 35 , once belt 20 is fastened . to apply the structure of fig4 to an afflicted hoof , the procedure described for fig1 to 3 is repeated , except that , before inserting the hoof into boot 10 , the upper coil ( 35 ) assembly is maneuvered around the hoof and to a raised position , say to the region of first or second phalanges bones , the boot 10 being then applied , followed by lowered positioning of the coil ( 35 ) assembly , in overlap with the upper portion 12 and with tabs 37 - 38 suitably positioned for belt ( 20 ) threading . such maneuvering of the coil ( 35 ) assembly is aided by the indicated flexible nature of associated potting , and it is also aided by providing removable jack or the like electrical connection for leads 36 -- 36 &# 39 ;. the completed assembly to the hoof results in coils 25 - 35 being supported at substantially parallel horizontal planes wherein the effective spacing h 1 between horizontal planes is less than the mean effective diameter of the coils . in the embodiment of fig5 the basic boot structure is generally as already described , except that the sole portion 11 &# 39 ; features a short peripheral retaining ledge 40 , and the upper portion 12 &# 39 ; features similar ledge means 41 at spacing h 2 above ledge 40 . the ledge means 41 may comprise a plurality of peripherally spaced lugs , thus permitting use of rear - corner slits ( as at 16 , in fig1 ), to define tabs 17 - 18 - 19 , for ease of boot application . the further structure of fig5 is a separate assembly , being a single multi - turn electrical coil 42 which may be a helical development of spaced turns , embedded for convenience in yieldable potting plastic into the form of a continuous flexible belt , of contour adapted for ultimate conformation to the upper boot portion 12 &# 39 ;; potted coil 42 will be understood to include a suitably shaped back panel region to which self - contained battery and pulse - generator means 30 is secured , with electrical - output connection to coil 42 . to apply the fig5 structure to an afflicted hoof , preferably re - shod with a magnetically transparent shoe , the flexible coil ( 42 ) belt is first manipulated over the hoof and then elevated , as in the case of the coil ( 35 ) assembly of fig4 . the boot is then fitted to the hoof , and thereafter the flexible coil belt 42 is manipulated over the ledge or lug means 41 , being self - retaining between ledges 40 - 41 and being also an effective replacement of belt 20 when thus positioned . the ryaby , et al . patents referred to above describe value ranges for various parameters of applied signals . generally , the signals found effective for equine treatment involve energy and frequency levels at or below lower limits of ranges specified by ryaby , et al . specifically , for equine applicators of the type herein described , it is found effective to provide asymmetrical pulse excitation of the described coil or coils . the pulses are of quasi - rectangular form , comprising a first pulse portion of relatively low - magnitude first polarity and of approximately 250 microsecond duration , followed by a second pulse portion of relatively great - magnitude second polarity and of approximately 5 microsecond duration . such pulses are repeated in bursts of 50 milliseconds , i . e ., at about 4 khz , and the bursts are repeated at a repetition rate of 2 hz . the amplitude of excitation signal is such as to develop a maximum body - induced voltage of approximately 0 . 15 millivolt per centimeter of treated tissue and / or cells , as measured by a one - cm diameter probe coil of the type described in said ryaby , et al . patent . stated more generally , present experience indicates that the burst - repetition rate should be in the range of 1 to 5 hz , that the pulses within each burst should be in the range of 2 to 5 khz , and that the burst duration should be approximately one tenth the period of burst repetition . the involved maximum magnetic - field strength is approximately 2 gauss . for the single - coil configurations of fig1 to 3 and 5 , coil 25 ( 42 ) may suitably comprise 40 turns of 24 awg enameled copper wire , to a nominal diameter of about 4 . 5 inches ; for the series - connected two - coil configuration of fig4 each of coils 25 and 35 may suitably comprise 25 turns of 22 awg enameled copper wire , to the same nominal diameter . while the invention has been described in detail for illustrative embodiments , it will be understood that modifications may be made without departing from the invention . for example , the routing described in connection with fig3 in connection with coil embedment in the sole portion 11 , is to be understood as purely illustrative , in that a boot 10 can be molded with coil 25 in place , thus providing an integrally formed structure which includes the coil ; alternatively , the coil may be a part of a pad or lining insert suitable for nesting within the boot cavity and resting on or adhered to the sole portion 11 .
the invention contemplates a boot removably adapted for attachment to an engine hoof and carrying at least one multi - turn electrical coil which effectively surrounds at least the bottom of the hoof . a pulse generator and power source are self - contained in a housing carried at the back side of the boot , with provision for electrically exciting the coil with a succession of therapeutically beneficial low - voltage unidirectional asymmetrical pulses .