US2100540A

US2100540A - Pressure fluid motor

Info

Publication number: US2100540A
Application number: US751010A
Authority: US
Inventors: Elmer G Gartin
Original assignee: Sullivan Machinery Co
Current assignee: Sullivan Machinery Co
Priority date: 1934-11-01
Filing date: 1934-11-01
Publication date: 1937-11-30
Anticipated expiration: 1954-11-30

Description

Nov. 30, 1937. E. G. GARTIN A PRESSURE FLUID MOTQR sheets-sheet 1 Filed Nov. l,- 1954 6 l 2 n 1 a fad W w, ,w am fa l e e o wav 0i m df 7 4 Z 166 z .4. a 3%/ a Nov. 30, 1.937. E. G. GARTIN PRESSURE FLUID MOTOR Filed Nov. 1, 1954 5 vSheets-Sheet 2 Invader."

Nov. 30, 1937.

E. G. G ARTIN PRESSURE FLUIDl MOTOR Filed Nov. 1, 1934 v3 sheets-sheet 5 r @u v 0 T 1 MN 2 N n w 6 MN. v d .wm [n w A ms. 2 E 1 0, mm. A v\\\\ 0 l 0 Q v 7 'dented Nov. 30, 1957 of Massachusetts 12 Claims.

This invention relates to pressure fluid motors, and more particularly to improved blow-varying means for a pressure fluid actuated motor of the reciprocating piston type.

An object of this invention is to provide an improved pressure iiuid motor. Another object is to provide improved blow-varying means for a pressure uid motor of the reciprocating piston type. Yet another object is to provide an improved pressure fluid motor of the reciprocating piston hammer type having embodied therein improved means for varying the force of the blow of the hammer piston so that a light, medium or heavy blow may be struck by theV piston, as desired. Still another object is to provide an improved pressure fluid motor of the impact type especially designed to use in hammer rock drills and having embodied therein improved blowvarying means for varying the blow of the hammer piston to suit different drilling conditions. These and other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawings there are shown for purposes of illustration two forms which the invention may assume in practice.

In these drawings,-

Fig. 1 is a longitudinal section through a ham-V mer rock drill having embodied therein one illusr trative form of the improved pressure iluid motor.

Fig. 2 is a view similar to Fig. 1 showingtheV moving motor parts in a different position. Y

Fig. 3 is a cross sectional view'taken on line 3-3 of Fig. 2. Y f f Fig. 4 is a cross sectional view taken on line 4 4 of Fig. 2.

Fig. 5 is a detail sectional view taken on line 5 5 of Fig. 4.

Fig. 6 is a detail sectional view taken on line 6 6 of Fig. 3.

Figs. 7 and 8 are views similar to Fig. 3 on a somewhat enlarged scale showing the valve chest member, by which the piston blow is varied, in dierent positions.

Figs. 9 and 10 are detail sectional views taken on lines 9-9 and I-I il, respectively, of Fig. 7.

Figs. 11 and 12 are detail sectional views'takenV on lines I I-II and I2-I2, respectively, of Fig. 8.`

Fig. 13 is a front end elevational view of the valve box. Y

Fig. 14 is a rear end elevational view or the valve box cover.

Fig. 15 is an enlarged view similar to Fig. 1 showing a modied form of the invention, the view taken on line |5-I5 oiV Fig. 16.

PRESSURE FLUID MOTOR Elmer G. Gartin, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation rATENT oFjFics g Application November 1, 1934, Serial No. 751,010

Fig. 16 is a cross sectional view taken on line lli-I5 of Fig. 15.

Figs. 17 and 18 are views similar to Fig. 16 showing the blow-varying control parts in different positions.

Fig. 19 is a detail sectional view taken on line Eili9 of Fig. 15.

In the illustrative embodiment of the invention shown in Figs. V1 to 14, inclusive, the improved blow-varying means is embodied in a rockv drill of thevpressure fluid actuated hammer type comprising a cylinder'l having a bore 2 containing a reciprocatory hammer piston 3. The hammer pistonv has ahead 4 Yfitting the cylinder bore 2 and a forwardly projecting piston rod 5 in the form l oi a striking bar for delivering impact blows to the shank 6 oi a usual rock drill steel. The piston rod 5 is guided in a bore 'I formed in a front cylinder head 8, andthe drill steel shank is supported in a chuck member 9 carried by a chuck sleeve I0 rotatably mounted in a front chuck housing I I in a well known manner.

In the rear end of* the cylinder is anrenlarged, bore I2 in alinement with the cylinder bore and closed at its rear end by a head block I3, vand arranged in this enlarged Ybore is valve mechav nism generally designated I4 and rotation mechanism designated.v in generalby I5.

The Vrotation mechanism may be of a well known Ytype comprising a ratchet ring I6 disposed in the extreme rear end of the bore I2 and serving, in Ythis instance, as a seat for the rearrhead block i3. On theinner periphery of this ring k,

rod 5 has straight Aflutes 22 interlocked with 4 straight ribs 23 on a chuck nut 24 threadedly secured within the chuck sleeve I9. As the motor piston moves rearwardly the pawls I3 engagingV the teeth of the ratchet ring hold the rifle bar 2B against rotative movement, and as a result, rota- 45 tive movement is imparted to the motor piston, and this rotative movement is transmitted v through the straight Vflutes 22on the piston rod and the straight ribs on the chuck nut 24 to the drill steel 6 so that, as the latter is percussively 5Q` boX cover 26, the valve box and cover being ar-j 5'5r` ranged in the bore I2 between the inner wall of the bore and the ratchet ring I6. In the present construction, formed in the valve box 25 and surrounding the rie bar 2G is an annular valve chamber 21 having reciprocably mounted therein an annular flat disc or plate valve 28. This valve is provided with a central bore 29 and is slidably mounted upon and guided by the cylindrical portion of the rie bar 20 in the manner shown. Formed on the va-lve box and cover, respectively, at the opposite sides of the valve chamber are annular grooves 3D and 3 I, while arranged concentrically within these grooves are

annular grooves

32 and 33. Also formed in the cover vZ6 in concentric relation with the grooves 3l, 33 is an outer arcuate groove 34 clearly shown in Fig. 14. In the present construction the valve chamber is of slightly larger diameter than the valve element 28 to provide a restricted annular passage past the peripheral edge of the valve through the valve chamber. Arranged in the head block I3 is a throttle valve 35 having a central supply chamber 36 communicating with any suitable pressure fluid source, and this central chamber is connected by a radial passage 31 to a passage 33 in turn communicating with an annular supply chamber 3S. The chamber 39 communicates through the space formed between the ratchet teeth of the ratchet ring I6 with an annular recess 43 formed in the rear face of the valve box 25, and this recess is connected by a series of longitudinal passages 4I with the annular groove 34. The central annular groove 3| formed in the rear face of the valve box cover is communicable with the rear end of the cylinder bore through a series of longitudinal passages 42. The outer groove 33 formed in the valve box is communicable with the front end of the cylinder bore through a pair of radial passages 43 formed in the valve box and ports 44, longitudinal passages 45 and ports 46. Formed in the wall of the cylinder intermediate the ends thereof is an annular piston chamber exhaust groove 41 communicable through a free exhaust port 48 with the atmosphere. The groove 33 in the rear face of the valve box cover is constantly supplied with pressure fluid through a passage 49 communicating with the supply groove 34, while the groove 32 is constantly supplied with pressure fluid through passages 53 communicating through the ratchet ring with the supply chamber 39.

When the parts are in the position shown in Fig. 1, pressure fluid may flow from the throttle valve through passage 38, supply recess 39 and thence through the spaces between the ratchet teeth, recess 4U, the series of longitudinal passages 4I, supply groove 34, through the valve chamber past the forward face of the valve 28 and through groove 3| and passages 42 to the rear end of the cylinder bore, the pressure fluid acting on the rear face of the motor piston to drive the latter forwardly to effect its working stroke, i. e. to strike an impact blow to the shank 6 of the drill steel. At this time the forward end of the cylinder bore is open to exhaust through groove 41 and exhaust port 48, and as the piston travels forwardly the groove 41 is cut oi by the piston head, and upon continued forward movement a substantial compression pressure is built up by the piston within the forward end of the cylinder bore. As the rear edge of the piston head overruns the exhaust groove 41, the rear end of the cylinder bore is connected to exhaust through exhaust port 48, and as a result the pressure within the rear end of the cylinder bore and in the groove 3| is substantially reduced. The compression pressure built up within the forward end of the cylinder bore,

passages

45, 45 and groove 30, aided by the pressure fluid in the concentric groove 32, overcomes the opposing reduced pressure in the groove 3l and the pressure fluid in groove 33, thereby throwing the valve from the position shown in Fig. 1 to the position shown in Fig. 2. When the parts are in the position shown in Fig. 2, the valve is held against the rear face of the valve box cover, cutting oi communication between the rear end of the cylinder bore and the annular supply groove 34, and pressure fluid then flows from the groove 34 through the valve chamber past the outer periphery of the valve, through groove 33, passages 43, ports 44, passages 45 and ports 46 to the forward end of the cylinder bore, the pressure fluid acting on the forward pressure area of the motor piston to drive the latter rearwardly to effect its retraction stroke. At this time the pressure at the rearward end of the cylinder bore is connected to exhaust through groove 41 and exhaust port 48, and as the piston moves rearwardly the exhaust groove 41 is overrun by the piston head, and upon continued rearward movement of the piston a substantial compression pressure is built up within the rear end of the cylinder bore. As the piston moves rearwardly, the forward edge of the piston head overruns the exhaust groove 41, connecting the forward end of the cylinder bore to exhaust, and as a result, the pressure within the forward end of the cylinder bore and in passages 45 and groove 33 at the rear side of the valve is substantially reduced. The compression pressure in the rear end of the cylinder bore and groove 3i at the forward side of the valve aided by the pressure fluid in the groove 33 overcomes the reduced pressure in the groove 30 and the pressure fluid in groove 32, and as a result, the valve is thrown from the position shown in Fig. 2 to the position shown in Fig. 1, these operations being rapidly repeated during normal operation of the motor.

Now referring to the improved blow-varying means, it will be noted that the valve box 25 and its cooperating cover 23 are maintained against to the cylinder into three different predetermined positions within the bore I2. The valve box is provided with a single longitudinal .groove 59 so that the valve box is always held against rotative movement by the dowel pin 55, the valve box cover being adjustable into its different positions with respect to the relatively stationary valve box. In this instance, the inner wall of the bore I2 is arcuately grooved at 6I), and the fluid supply groove 34 is at one end communicable with the groove 60 through a port 6I, as clearly shown in Figs. 7 and 8, while the adjustable valve box cover 26 is provided with a pair of auxiliary passages S2 Vand 63 for connecting the groove 33 with the groove 60, as clearly shown in Figs. 9 and 10. The relatively stationary valve box 25 is also provided with a pair of

auxiliary passages

34 and 35 for connecting the groove 32 with the groove 34. The

passages

62 and 63 extend radially through the exterior periphery of the valve box cover, while the passages S4 and 65 extend longitudinally through the forward face of the valve box, and in the positions of the valve box cover as shown in Figs. 6

and 9,'the passages 62 and 63are blanked oft` by the wall of the bore I2 and the

passages

64 and 65 blanked 01T by the rear face of the valve box cover in the manner shown in Fig. 5.

VVWhen the valve box cover is in the position shown in Fig. 3, the motor, as described above in regard to Figs. 1 and 2, operates in a normal manner to deliver a full impact blow with full piston stroke, and when the parts are so adjusted, the drilling motor is adapted to drill in relatively hard rock. When it is desired to drill under relatively soft drilling conditions, it is desirable to lessen the intensity of the blow of themotor piston to deliver a relatively light blow to the drill steel shank. During this soft drilling condition the valve assembly is removed from the cylinder and the valve box cover is adjusted with respect to the valve box to the position shown in Fig. 8 by removing the dowel 55 and turning the cover so that the dowel engages the groove 58. When the valve box coveris in the position shown in Fig. 8, the

passages

62 and 63 are in communication with the groove`60 so that through these

passages

62 and 63 an auxiliary supply of pressure uid, supplementing the pressure fluid in the

passages

49, 49, is conducted to the groove 33, while at the same time an auxiliary supply of pressure fluid supplementing the flow through the passages 56, 5l), is conducted to the groove 32 through the

passages

64 and 65 at that time communicating with the groove 34. Accordingly, since there is an additional ow of pressure fluid to the

grooves

32 and 33, the throwing action of the -distributing valve 28 is materially quickened while at the same time there is an increased volume of pressure fluid supplied through the valve chamber to the grooves and 31 connected to the opposite ends of the cylinder bore.

While the rate of travel of the valve while it is moving may not-be increased, and while the positionsoccupied by the piston at the instant ofv valve throwing may not be altered, the admission of greater quantities of. motive fluid to the rear end'of the cylinder after the valve is thrown and before the piston reaches its extreme rear position, will diminish the distance the piston travels rearwardly. In other words, the 'rearward stroke of the piston will be shortened, and accordingly the piston will not attain, on its striking stroke, the same momentum which attends its full-length stroke when the'passage 49 is in communication with the groove 33. Moreover, because of the increased qauntity of fluid which is admitted to the forward end of the cyilnder during the forward stroke of the piston, after the rear end of the piston has uncovered the exhaust port and allowed the valve to be thrown torposition for the rearward stroke, there will be a somewhat increased cushioning eiect because the piston will make the last portions of its working stroke against a somewhat higher pressure in the for-V ward end of the cylinder. It will thus be appreciated (1) that the initial momentum of the piston will be reduced, surprising though this may seem, and (2) that from that momentum there will be a greater subtraction due to the increased quantity of air entering the forward end of the cylin- Ider before the piston strikes the steel. Therefore, while the motor is not short-stroked very materially in the sense of its forward travel (the and 33 is supplemented'by but a single passage 63 and a single passage 65, the

other passages

62 and 64 being blanked on by the wall of the bore 32 and the inner face of the valve box cover, repectively. It is evident that when one of each of the

passages

62, 63 and 64, 65 is blanked off, the auxiliary supply of 'pressure fluid to the

grooves

32 and 33 is cut substantially in half so that the throwing'action of the valve and the intensity of the blow of the piston, due to the increased volume of air flowing to the cylinder is substantially midway between thefull blow position shown in Fig. 3 and the light-blow. position shownY infFig. 8.

In the modified form of the invention shown Y in Figs. l5 to 19, inclusive, the pressure fluid motor is similar tothat shown in'Fig'. 1, but the means for supplementing the' supply of pressure .fluid to the

grooves

32 and 33 isY somewhat In this instance, there is arranged a changed. rotatable control member 68 mounted in a bore 69 in the cylinder and having an operating handle 10. This member 68 is provided with a central .passage H'communicable through the passage 12 with the port 31 of the throttle valve 35. The inner wall of the bore 69 isigrooved at 13 and lthe member 68 is provided with a pair of

radial passages

14 and 15 for connecting the passage 1l with the groove 13. Communicating with'the groove 13 is alongitudinal passage 15-7connected through a port 11 with a groove 18 and passages 19 communicating with the groove 32, and

through a port 85 communicating wi'thafg'roove 8l andl passages 82 in vturn communicating with the groove 33. In this instance the valve boxV 25 and valve box cover 26 are held against rotative movement Vin the ,bore l2 .bya dowel pin 55 engaging alined grooveslrin the valve box cover.V

When the controlmrembe'rr 6B'is1-in the position shown in Fig. 16, the pressure fluid motor operates with full piston stroke to deliver Va full impact blow to the drill 'steel shank." When it isdesred to lighten the-intensity of the blow of the motor piston during soft drilling'conditions, the operator grasps the handle 19 to rotate the control member '68 from the positionshown in Fig. 16

to the position shown-in'Fig 18. At this time the' Yiiow of Vpressure iluid to the groove 32 through the passages 5l), 50'is supplemented by the pressure uid flowing through passage 1I,

passages

14, 15, groove -13, passage 15, groove 18 and

auxiliary passages

19, 19, while the ow ofpressure uid to the groove 33 through the

passages

49, 49 is supplemented by the `iiow of ypressure fluid from passage 16 through passage 88, Vgroove 8l and passages 82', 82. Asa result,-there is, increased pressure in the grooves 32, `33 which quickens the throwing actionof the valve, while at the same time an increased volume of pressure fluid ows through grooves 30 and 3l Ytothe opposite ends of the cylinder bore, thereby causing a back pressure to buildup in the opposite ends of the cylinder bore which causes lightening 'of the motory pistonv in the. manner clearly described above in connection with theA rst form of the invention. When it is desired to operate the pressure iiuid motor to suit a medium drilling condition, the control member 68 is rotated into the position shown in Fig. 17 with only one passage 19, 82 supplying pressure fluid to the

grooves

32 and 33. Otherwise this form of the invention is the same as that above described.

'I'he results of changing rate of fluid supply to the

grooves

32 and 33 will be more readily appreciated when it is noted there is a pressure dropV in each of these grooves once in each cycle, and that the cumulative pressures in these grooves and compression pressures time valve'throw.

As a result of this invention, it will be noted that an improved pressure fluid motor is provided having embodied therein improved and simplified means for varying thev blow of the motor piston, it being possible to vary the piston blow to suit different drilling conditions. It will further be noted that by utilizing the valve box cover as a control element for the blow varying means, it is possible to eifect a variation in the piston blow by means of a very simple change in adjustment of parts, it being necessary only to rotate the valve box cover slightly lwith respect to the valve box to effect such blow-varying function Other uses and advantages of the invention will be clearly apparent to those skilled in the art.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be further modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable therein, fluid distribution means for effecting reciprocation of said piston including a valve box having a valve chamber, a valvebox cover, a fluid actuated fluid distributing valve reciprocable in said valve chamber, valve throwing means, and means associated with the fluid distribution means for varying the piston blow including said valve box cover, the latter being adjustable relative to the valve box to effect such piston blow variations.

2. In a pressure uid motor, a cylinder having a bore, a piston reciprocable therein, fluid distribution means for effecting reciprocation of said piston including a valve box having a valve chamber, a valve box cover, a uid actuated fluid distributing valve reciprocable in said valve chamber, valve throwing means, and means associated with the fluid distribution means for' varying the volume of the pressure fluid flowing past said valve to the cylinder bore to vary the piston blow and including said valve boxcover, the latter being adjustable relative to the valve box to effect such piston blow variation.

3. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable therein, fluid distribution means for effecting reciprocation of said piston including a valve box comprising relatively adjustable valve box elements cooperating to provide a valve chamber, a fluid actuated fluid distributing valve movable in said valve chamber, valve throwing means, and means associated with the uid distribution means for varying the volume of pressure fluid flowing past said distributing valve to the cylinder bore to vary the piston blow and Aincluding the adjustable element of said valve box, the latter being adjustable relative to the other element of the valve box to effect such piston blow variation.

4. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable therein, a valve chest having a valve chamber, throttle controlled passage means for supplying pressure fluid to said valve chamber, a iiuid actuated distributing valve in said valve chamber, passage means controlled by said valve for supplying pressure fluid to the opposite ends of said cylinder, and means adjustable to effect a variation in the flow area of said first mentioned passage means for varying the volume of pressure fluid flowing therethrough and through said second mentioned passage means t0 the opposite ends of the cylinder while the supply pressure and throttle control remain the same to vary the blow of the piston.

5. In a pressure iluid motor, a cylinder having a bore, a piston reciprocable therein, a valve chest having a valve chamber, throttle controlled passage means for supplying pressure fluid to said valve chamber, a fluid actuated distributing valve in said valve chamber, passage means controlled by said valve for supplying pressure fluid to the opposite ends of said cylinder, and means adjustable to effect a variation in the flow area of said rst mentioned passage means for varying the volume of pressure fluid flowing therethrough and through said second mentioned passage means to the opposite ends of the cylinder while the supply pressure and throttle control remain the same to vary the blow of the piston, said adjustable means including a blow-varying element adjustable into positions to eiect a heavy blow, a medium blow and a light blow.

6. In a pressure fluid motor, a cylinder having a bore, a hammer piston reciprocable therein for delivering impact blows to a working implement, a valve chestV having a valve chamber, throttle controlled passage means for supplying pressure fluid to said valve chamber, a fluid actuated fluid distributing valve movable in said valve chamber, passage means leading from said valve chamber to said cylinder bore and'controlled by said valve for supplying pressure fluid-to said cylinder bore to eiiect reciprocation of said piston, and means operative to provide different flows of pressure fluid past said valve during like periods of valve opening while maintaining the same opening of said second mentioned passage means leading from the valve chamber to the cylinder bore and while the supply pressure and throttle control remain the same, thereby to vary the impact blow of said piston.

.7. In a pressure fluid motor, a cylinder having a bore, a hammer piston reciprocable therein for delivering impact blows to a working implement, a valve chest having a valve chamber, throttle controlled passage means for supplying pressure fluid to said valve chamber, a uid actuated uid distributing valve movable in said valve chamber, passage means controlled by said valve for supplying pressure fluid to the ends of said cylinder bore to effect reciprocation of said piston, and means for increasing the quantity of fluid flow to the ends of the cylinder bore in a predetermined unit of time of valve opening while the supply pressure and throttle control remain the same to vary the impact blow of said piston.

8. In a pressure fluid motor, a cylinder having a bore, a hammer piston reciprocable therein for delivering impact blows to a working implement, a valve chest having a valve chamber, throttle of the cylinder when said valve places said Valve chamber in communication with said passage means and While the supply pressure and throttleV Y control remain the same, thereby to vary the irn-Y pact blow of said piston.

9. In a pressure fluid motor, aV cylinder having a bore, a hammer piston reciprocable therein for delivering impact blows to a working implement, a valve chest having a valve chamber, throttle controlled passage means for supplying pressure fluid to said valve chamber, a fluid actuated fluid distributing valve movable in said valve chamber, passage means controlled by said valve'v for supplying pressure fluid to the ends of said cylinder bore to effect reciprocation of said piston, and means for increasing the rate of fluid admission to said cylinder through said second mentioned passage means for a given rateV of operation of said motor in terms of blows per minute While the supply pressure and throttle control remain the same, thereby to Vary the impact blow of said piston.

10. In a pressure fluid motor, a cylinder having a bore, a hammer piston reciprocable therein for ydelivering impact blows to a working implement, a valve chest having a valve chamber, throttle controlled passage means for supplying pressure fluid to said Valve chamber, a fluid actuated fiuid distributing valve movable in said valve chamber, passage means controlled by said valve for supplying pressure fluid to the opposite ends of said cylinder bore to effect reciprocation of said piston, valve throwing means, and adjustable means communicable with said second mentioned passage means for varying the volume of pressure fluid flowing past said valve through Asaid 'y second mentioned passage means to the cylinder bore while the supply pressure and throttlecontrol remain the same, to vary the impact blow of said piston.

l1. Ina pressure fluid motor, a cylinder having i' a bore, a hammer piston reciprocable in said bore Y fordelivering impact blows to a working implement, a valve chest having a valve chamber,`

throttle controlled passage means for supplying pressure fluid to said valve chamber, afluid actuated fluid distributing valve movable in said valve chamber for controlling the supply of pressure fluid to thelopposite ends of the cylinder bore to effect-reciprocation of said piston, said valve when in oneposition in said valve chamber `admitting pressure fluid through the valve chamber past said. valve to one end of said cylinder bore, and adjustable means for varying the volume of pressure fluid flowing past said valve'when the latter is in said position to one end of the cylinder bore while the supply pressure and throttle controlremain the same, to vary the impact blow of said piston. Y Y p Q Y 12. 'In apressure fluid motor, a cylinder having a bore, a hammer piston reciprocable in said bore for deliveringimpact blows to a working implement, and fluid distribution means for effecting iable area communication with said valve, placed .Y g

in communication with said passage forming means in the open positions of said Valvewhile` y reciprocation of said; piston including means y 7 Y the supply pressure'and throttle control remain 1 CERTIFICATE 0F CoRREcTIoN. Patent No. 25100, 514.0., November 50, 195'?.

ELMER G. GARTIN.

It is hereby certified that error appeara in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 7h, after "thei second occurrence, insert vintenaity /of the blowof the; and that the said Letters Patent should be read with this `c:c;r'reo1:.io1'1 therein that the same may conform to the record of the oase in the Patent Offie. y

signed and sealed this ist day of February, Al D; 1958.

Henry Van Arsdale, (Seal) Acting Comniasoner of Patents.,