fig1 and 3 are schematic illustrations of prior art human anatomy which were discussed earlier on pages 3 - 5 of the specification herein . specifically , fig1 parts a - e , shows a sequence of venous volume changes in the calf with walking , wherein a represents resting , b represents the heel pressed against a support ( early muscle contraction ), c represents the entire foot pressed against a support ( muscles fully contracted ), d represents the knee flexed ( forefoot compressed to floor , soleus contracted , gastrocnemius relaxed ), and e represents the foot now unloaded ( all muscles relaxed ). fig2 parts a and b , illustrate femoral valve cusps pre - and post repair . before repair ( part a ) the valve cusp was loose and floppy and severely incompetent . after repair ( part b ) the valve was completely competent . the valve repair involves placement of a series of interrupted sutures designed to shorten the leading edge of the valve cusp . interrupted sutures are placed repeatedly until the leading edge of each cusp lies gently across the surface of the vein , and is neither taut nor lax . fig3 a and 3b are described in detail on page 4 and 5 above . the preferred embodiment of the new invention is shown in fig6 b as applied to a person &# 39 ; s leg and in fig4 in schematic form . the components as seen in fig4 are a pump 20 , a switchable valve 22 , a bladder or flexible air chamber 24 , an inlet check valve 25 , a one - way valve 26 and a pressure gage 27 . between valve 22 and bladder 24 is an inflating line 28 and a separate exchange line 29 . in use the bladder 24 is applied to or wrapped around and secured to the patient &# 39 ; s leg . valve 22 is switched to open the line 28 to pump 20 , and to close the line 29 to pump 20 . a compression stroke of pump 20 as applied by the person &# 39 ; s heel when walking drives air via open line 28 through one - way valve 26 into the bladder . this air cannot escape via line 29 which is closed by valve 22 ; the air cannot escape via line 28 because of one - way valve 26 . by beginning to take a step the person &# 39 ; s heel lifts off the pump which then expands and draws in air from the atmosphere via inlet valve 25 while the outlet valve 23 is closed . on the next step downward the heel compresses the pump and drives this additional charge of air through line 28 into the bladder further inflating it . this charge of air from the pump cannot flow elsewhere than to the bladder , because valve 22 is closed to line 29 and valve 27 is one - way &# 34 ; in &# 34 ; only . after a number of steps , 5 to 10 , the bladder is adequately inflated , which can be verified by pressure gage 27 . then inlet valve 25 is closed by control 25a , and valve 22 is switched to open line 29 between pump and bladder 24 and to close line 28 from the pump to the bladder . now there may be free reciprocal flow in line 29 between the pump and the bladder with each step onto and off of the pump . as discussed on page 10 , lines 18 - 19 herein , initial inflation could be from an external source of compressed air instead of by suction from the pump operation . the optional alternate air source is indicated as 25b and a dotted line communicating with valve 25 and control 25a . finally , when the patient seeks to terminate this session he merely opens release valve 23 and air over atmospheric pressure will flow out of the system via line 29 . the new venous boot , also called airsoc * or self - inflating boot of the present invention is shown generally schematically in fig5 - 8 . in fig5 the venous boot 30 comprises the wrap around outer shell 32 , the velcro ® tabs 34 for adjustably securing the boot around the foot and calf , the valve assembly 36 which is located in a convenient place for the user to reach and operate with one hand , and a valve assembly / tube cover 38 which houses the valve conveniently in the vicinity of the person &# 39 ; s ankle . fig1 shows the outer shell 32 in its flat form as a two - layer sheet 50 having a generally trapezoidal shape with top edge 51a and bottom edge 51b . the peripheral edges of the two layers are sealed to form an inflatable bladder which is described in greater detail later . fig6 is a partially cut away view of the venous boot of fig5 and illustrates the bladder or air chamber 40 divided into separate pockets 40a , 40b , 40c etc . a lower sock 42 is situated at the bottom of the boot for surrounding or encasing the middle of the user &# 39 ; s foot . adjacent the lower sock is the upper sock portion 43 , and at the top of the upper sock is the valve assembly housing 37 . situated below the user &# 39 ; s foot and situated within a pocket at the bottom of the lower sock or below and adjacent lower sock bottom is an innersole pump 44 . from the innersole pump is a connector tube 46 which extends to the valve assembly 36 in housing 37 . an outlet tube directs air from the valve 36 into the bladder 40 . fig7 and 8 illustrate further details of the construction of the lower and upper sock or slight variation thereof for this boot . the same reference numbers are used for similar components as in fig6 . the boot &# 39 ; s outer shell 32 has a lower part 32a which is joined to the upper sock 43 along a seam 45 . an additional seam 47 is shown joining the lower sock 42 to the upper sock 43 as shown in fig7 and 8 . there is stitching 48 forming a path for the tubing 46 on the inside of the sock . this tubing 46 leads to the valve 22 situated in valve assembly housing 37 . obviously it is important that tubing 46 be situated and protected such that it will not get pinched and block any air flow from pump 44 ( fig6 ) to the valve 36 . also the valve is situated in this embodiment at the rear of and slightly above the ankle so that it is easily accessible but not likely to interfere with walking or be struck by the opposite foot or by anything against which the leg is likely to brush . the lower sock 42 is elastic that is stretched circumferentially when put on the foot and applies inward compression to the foot . upper sock 43 is made of the same elastic to snugly encompass the heel and the remainder of the foot rearward of the lower sock . the elastic may be generally similar to the elastic strip used in an ace * bandage . fig9 shows greater detail of the valve assembly housing or pocket 37 wherein valve 36 is situated . the valve assembly 36 is positioned to engage and seal with the upper end of tube 46 . at the top of the valve is a lever or knob for the user to easily actuate the valve between its various modes of operation . fig1 shows a cutout pattern or form for the bladder or air pressure chamber . this form is somewhat butterfly - shaped in appearance , with a central part 52 with opposite left and right or side wings 53a and 53b . these wings have mating tab parts with velcro ® tape 54a and 54b respectively so that the central part 52 can be wrapped around a person &# 39 ; s leg , and then tab 54b can be flapped over to engage the mating velcro ® tab 54a . the velcro ® tape is situated such that it can engage in a variety of different positions , and thus the tightness of the boot wrapped around the leg can be easily adjusted . there are smaller wings 55a and 55b which engage similarly as the other wings at the lower part of the leg below the calf . this sheath or web is wrapped around the leg as readily seen in fig5 and 6 where the velcro ® tabs are visible in front . fig1 a shows a cross - sectional view of the boot webbing of fig1 . as is apparent this web is formed of two layers 52a on the inside and 52b on the outside . these layers are joined together by heat sealed welds at numerous places represented by the example 56 . as can be seen in fig1 and 10a the air chamber extends through the majority of the web except that internal air flow must pass around any of these welded areas 56 which join and secure layers 52a and 52b together . this is to prevent 52a and 52b from billowing out into the shape of a balloon . accordingly this bladder can be inflated so that inside surface 52a presses in the direction of 52c ( see fig1 a ) while retaining its general shape in the form of a mattress . these various welded areas 56 optionally and as shown have apertures 59 punched therethrough to allow air to flow in through the boot and onto the patient &# 39 ; s skin or sock or other covering that he might be wearing . fig1 further shows the pocket area 59p for receiving and holding the valve 36 if appropriate cutouts are made for tube 46 from the pump to reach and connect with the valve and for another tube to extend from the valve to an inlet nipple ( not shown ) into the bladder . the air chamber of the bladder of the preferred embodiment is two layers of 51 / 2 mil polyurethane . in the structure shown herein the outer layer is 420 dernier nylon with a 51 / 2 mil coating of polyurethane as its inner surface . the peripheral edges of the two polyurethane layers and various spaced intermediate areas 56 of these layers are heat sealed together . the nylon fabric is generally non - stretchable to provide appropriate strength to the bladder . this fabric is available from mann industries inc . of birmingham , mass . 01701 . fig1 a - 11e show the construction of the foot pump ( innersole pump ) 44 as indicated schematically in fig6 . this is a one - piece molded resilient rubber or plastic device . fig1 a shows embodiment 60 as somewhat rectangular with the rear end 60r rounded to generally conform to the inner heel area of a person &# 39 ; s shoe . fig1 b shows that the pump 60 is tapered generally conforming to the arch of a person &# 39 ; s foot so that top portion 60a is positioned directly under the person &# 39 ; s heel and arch , and lower portion 60b resides adjacent the bottom of the person &# 39 ; s shoe . fig1 c is a cross - sectional view of fig1 b with 62 being an aperture of inlet / outlet nipple 62 which is later connected to tube 46 as seen in fig6 . fig1 d is a rear end elevation view , and fig1 e is a sectional view similar to 11d . finally , fig1 f is a sectional view showing the inner structure of the device of fig1 a and 11e . fig1 f shows more clearly the outlet nipple 62 which is directed to and coupled to tubing 46 . as stated earlier , this pump is a one - piece molded resilient plastic or rubber apparatus . obviously , there are many variation constructions , including a flexible but not resilient pump chamber with an internal spring urging the pump to its expanded state . as shown the pump has an air volume of about 4 - 5 cubic inches , a 65 % pumping efficiency , and is constructed of an 80 durometer elastomeric material that can sustain multiple impacts at pressures of up to approximately 385 psi without rupture . fig1 shows a plan view of the valve assembly 70 as might be used for the valve assembly 36 seen in fig5 - 9 . fig1 , 14 and 15 show sectional views of this valve in three different modes of operation . valve 70 has two fittings or nozzles 71 and 72 for connection to the exchange line 29 and the inflation line 28 respectively of fig4 . the inner structure and operation are described as follows . the valve assembly 70 ( designated 22 , 23 , 25 in fig4 a and 36 in fig5 - 8 ) comprises a bottom or housing 73 which defines a cylindrical bore 74 , a rotary piston 75 , an actuator or rotary knob 76 , a disc check valve 77 , and a relief check valve 78 . this valve assembly has three modes of operation ; however , first we will describe certain structural and functional features . when the piston is rotated air flow passages are established as shown by the dashed line 79 in fig1 or by dashed line 8 in fig1 . these lines include passages transversely through the piston in fig1 . when the piston is rotated 90 ° as shown in fig1 the above - mentioned through - passages are blocked and sealed , but instead there is a different internal passages shown by dashed line 81 whereby the piston blocks the prior passages . disc check valve 77 allows flow from left to right in fig1 but not from right to left in fig1 . relief check valve 78 allows flow in from the atmosphere per arrows 81 in fig1 when the pump creates a partial vacuum as applied to fitting 71 . under a positive pressure situation in fig1 the relief check valve 78 remains closed . in the bladder fill mode of fig1 , the foot pump outlet tube is connected to fitting 71 . air flow under positive pressure occurs along dotted line 79 through one - way check valve 77 and into the bladder . successive pressure strokes of the pump add incremental charges of air into the bladder until it is adequately filled . with each pressure stroke air can enter the bladder but not leave . all other passages within the valve assembly 70 are blocked . after each pressure stroke of the pump there is a suction stroke , foot pump fill mode of fig1 , where the pump expands and draws in a new charge of air from the atmosphere . the new air comes from outside the system via relief check valve 78 and passage 80 . during this mode the pump creates negative pressure in the system , which both draws in air via valve 78 and holds closed check valve 77 , the latter thus preventing escape of air from the bladder while the pump draws in a fresh charge of air . next is the reciprocating mode illustrated in fig1 where piston 75 has been rotated 90 °, passage 79 ( fig1 ) is blocked , and air pressure within the &# 34 ; system &# 34 ; comprising the pump , the bladder and interconnecting passage 81 is al positive . accordingly , any air in part 79a of line 79 would cause check valve 77 to remain closed , and air would merely reciprocate in line 81 between the pump and the bladder as the person walks . lastly , when the user wishes to cease the pump action and deflate the system , he merely rotates the knob and piston back 90 ° to the condition of fig1 , and then presses actuator 90 of relief valve 78 . this allows air under pressure to exit from the pump via line 80 ( fig1 ) and from the bladder via line 79a ( fig1 ) by bleeding out past check valve 77 , the latter being closed in reaction to pressure spikes , but not under this deflation bleeding condition . in the operation of this valve the bladder is inflated to about 21 / 2 to 3 psi or other comfort level . in reciprocating mode the pressure periodically spikes to about 5 psi . the relief check valve includes a spring that holds this valve closed with a force of abut 0 . 3 pounds . during fill mode ( fig1 ) the pump &# 39 ; s suction is easily enough to open this valve . in summary , valve assembly 70 is a very compact and efficient apparatus to handle all modes of operation with a single small mechanism , and with knob or actual movable between only two states , and finally a simple relief valve to deflate . obviously , all these functions could be separated : the intake valve could be on or associated with the bladder directly and the relief valve could be on or associated with the bladder directly . then the principal reciprocating mode would be much simpler ; however , such would require three separate valves instead of one as disclosed herein . the invention has been described with particular reference to a presently preferred embodiment . however , it will be apparent to one skilled in the art that variations and modifications of the disclosed embodiment are possible without departing from the spirit and scope of the invention claimed below .
a portable apparatus for applying cyclic pressure to veins within a person &# 39 ; s leg by applying cyclic pressure to an outer surface of the leg , the apparatus comprising a first air chamber having a flexible wall portion adapted to be situated adjacent an outer surface of the leg , a second air chamber adapted to be positioned beneath the person &# 39 ; s heel , this second chamber being compressible to force air out of it when the person &# 39 ; s heel bears downward thereon and returnable to its uncompressed state when the downward heel force is removed therefrom , and conduit means for permitting air flow between the first and second air chambers , whereby air flows from the second chamber into the first chamber and pressure is cyclically increased in the first chamber urging the wall portion against the leg when the person &# 39 ; s heel presses downward on the second chamber , and air flows from the first to second chamber and pressure on the leg is reduced when the person &# 39 ; s heel stops pressing on the second chamber .