US3439695A - Fluid-driven timing mechanism - Google Patents

Description

April 22, 1969 P. BAUER FLUID-DRIVEN TIMING MECHANISM Filed Sept. 29, 1965 INVENTOR PETER BAUER ATTORNEYS United States Patent Office 3,439,695 Patented Apr. 22,, 1969 ABSTRACT OF THE DISCLOSURE A fluid-driven timing mechanism comprising a fiuidic oscillator, a pallet mounted for oscillatory movement about a pivot, and a rotatably mounted pallet wheel operatively engageable bysaid pallet. The pallet is oscillated about its pivot in response to oscillations by said oscillator whereby to rotate the pallet wheel in a predetermined direction. I

' The present invention relates to timing mechanisms and,

more particularly, to a pure fluid driver for timing mechanisms. In the more conventional, wholly mechanical timing mechanisms, a main spring is employed to drive, through an appropriate gear linkage, a timing wheel whose rate of rotation is determined by a balance wheel and hair spring arrangement. Such mechanisms are subject to wear damage due to shock and vibration and to various temperature effects.

In accordance with the present invention, a timing mechanism is provided in which the main spring, balance wheel and hair spring may be replaced by a pure fluid oscillator, thereby eliminating a number of sources of inaccuracy, wear and damage common to the more conventional timing mechanisms.

' In accordance with the present invention, a pallet and pallet wheel are provided and means are provided for driving the pallet by means of a pure fluid oscillator. Since the pallet may be made quite light and various mechanisms are known for rendering fluid oscillators insensitive to loading, the basic frequency of the system may be made substantially independent of the load and dependent only. upon the characteristics of the oscillator. Since the oscillator is a pure fluid system, it is known to be free from such effects as wear and damage from mechanical shock and vibration. Further, various methods are known for rendering such oscillators relatively insensitive to temperature. Thus, there may be provided a quite simple and reliable mechanism which is long-lived and has excellent timing properties.

It is an object of the present invention to provide a mechanical timing mechanism in which a fluid oscillator is employed to drive a timing gear train of a conventional type.

It is another object of the present invention to provide a clock mechanism in which the basic power supply and timing functions are performed concurrently by a pure fluid oscillator.

It is still another object of the present invention to provide a timing mechanism in which a pallet is driven by a pure fluid oscillator, the pallet driving a pallet wheel to which a conventional timing gear train may be connected.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a plan view of one embodiment of the present invention;

FIGURE 2 is a view in cross section taken along section line 22 of FIGURE 1; and

FIGURE 3 is a plan view of another embodiment of the present invention.

Referring specifically to FIGURE 1 of the accompanying drawings, there is illustrated a first embodiment of the present invention. The invention contemplates a pure fluid oscillator generally designated by the reference numeral 1 employing a pure fluid flip-flop having a power nozzle2 and a pair of control nozzles 3 and 4 disposed on opposite sides of the power nozzle 2. The power nozzle issues a stream of fluid into and through an interaction region 6 towards three outlet passages; more particularly, a right outlet passage 7, a left outlet passage 8 and a center outlet passage 9. The center outlet passage 9 is connected to a dump or vent 11 which may return fluid to the atmosphere or to the low pressure side of a pump supplying fluid to the nozzle 2.

Connected between the outlet passage 7 and the control nozzle 3 is a first negative feedback loop generally designated by the reference numeral 12. This loop may comprise a capacitance or volume 13 and a long-line or inductive element 14 to provide a tuned circuit for determining the frequency of oscillation of the oscillator. A second feedback path 16 is provided between the outlet passage 8 and the control nozzle 4. This feedback channel 16 is basically the same as the path 12 and provides for the same basic frequency of the oscillator as the channel 12.

In operation of the oscillator 1, assume for instance that fluid is initially directed to the outlet channel 7. A portion of the fluid continues through the outlet channel 7 while another portion is directed into the feedback path 12. After a time determined by the basic characteristics of the feedback channel 12, the fluid flowing into the feedback channel issues from the control nozzle 3 with sufficient momentum to deflect the stream of fluid to the outlet passage 8. During the cross over interval, the majority of the fluid is directed to the output passage 9 and is dumped through the vent 11. It will be noted that the entries to the passages 7 and 8 are relatively small compared to the egress orifice of the passage 9. This feature is employed in accordance with well-known principles of fluid amplifiers so that a relatively high pressure portion of the stream enters the passages 7 and 8 whereas relatively low pressure portions enter the dump passage 9 when the stream is fully switched to one or the other of the output passages 7 and 8.

When the fluid is directed to the output passage 8, a portion thereof proceeds through the passage while another portion is directed to the feedback channel 16 and eventually issues through the control nozzle 4. Upon issuance of fluid from the control nozzle 4, the stream is again diverted to the output channel 7 and the system continues in the manner described above so that the power stream is switched at predetermined intervals between the passages 7 and 8. Thus, the oscillator 1 determines a basic timing cycle for the apparatus which cycle may be determined by the elements in the The passages 7 and 8 extend beyond 't he ingressorifices of the feedback networks 12 and 16 and enter into opposite sides of a generally sector-shaped opening 17 in which is located a leg 18 of a pallet 19. The passages 7 and 8 terminates at their entry into the sector-shaped opening 17 in nozzles 21 and 22, respectively, so as to issue a relatively high velocity stream of fluid into the sectorshaped opening 17. It will be noted that the pallet 19 is pivoted about a shaft 23 having its center located such that, when the-pallet is in its-right or left extreme position, the side surfaces of the pallet are generally parallel to the adjacent sidewall-of the'chamber 17. Thus, in the position illustrated in- FIGURE 1,theright surface. or wall of the leg-18 of the pallet19'lies against and is parallel to the right wall of the chamber 17. Conversely, when the pallet is rotated counterclockwise, the left wall thereof lies generally parall'el to and in 'contactwith the left-wall of the chamber 17. i T I Two vent passages 24 and 26 are located'at the right and left sides, respectively, of the chamber17, with each terminating in a vent which may return fluid to the low pressure side of'the pump supplying the nozzle 2 to atmosphere or to another source 'of reference pressure. The pallet is provided with a pair of opposed grooves 27 and 28 in its right and left surfaces, respectively, the groove 27 providing a passage from the nozzle 21 to the vent channel 24 when the pallet is rotated fully clockwise. Similarly, the groove 28 provides a passage from the nozzle 22 to the vent channel 26 when the pallet is rotated fully counterclockwise. The reason for the above arrangement is to provide a passage between the nozzle and the vents to permit escape of the fluid issued by the nozzles, for instance nozzle 21, and thus prevent undue build-up of back pressure in the passage 7. Such an increase in pressure may unduly influence the frequency of oscillation of the oscillator.

In operation of the apparatus and assuming that the fluid stream issued by nozzle 2 has just been switched to the passage 7, fluid issues from the nozzle 21 and, until the pallet moves, immediately exits through the passage 24. The pressure exerted against the pallet causes it to rotate about the pivot 23 so that the entire pallet is rotated counterclockwise. The fluid flowing through the nozzle 21 now begins to fill the space to the right of the arm 18 of the pallet maintaining a pressure thereon to sustain the rotation of the pallet until it achieves a position against the left sidewall of the sector-shaped opening 17. After an interval determined by the characteristics of the feedback channel 12, the nozzle 3, connected to the feedback path 12, issues fluid so as to divert the fluid stream of the oscillator to the output channel 8. The nozzle 22 now issues fluid and produces clockwise rotation of the pallet 19 until its arm 18 contacts the right side- 'wall of the sector-shaped opening 17. The power stream is again switched by issuance of fluid from the nozzle 4 and the pallet is again rotated counterclockwise. The oscillation of the pallet 19 thus proceeds at a rate determined by the basic rate of oscillation of the power stream of the oscillator 1.

It will be noted that the vent passages 24 and 26 provide for escape of the pressurized fluid from the sector 17 as the pallet arm 18 is oscillated from one extreme position to the other. Thus, when the arm 18 is against the right side of the right wall of the sector-shaped opening 17 and flow through nozzle 22 is discontinued, the pressure to the left of the arm 18 falls rapidly due to escape of fluid through the vent 26.

The passages 7 and 8 may be provided with vents 29 and 31 to provide impedance matching in the system. More specifically, to the extent that the fluid flows to the passage 7 more rapidly than it may flow outwardly through the nozzle 21, the excess fluid is vented through the vents 29 and 31 which are in communication with the passages 7 and 8.

feedback passages 12 and 1 6.

V .Th e i d pt d.. to driv palle wheelill mounted for rotation about a shaft 30. The pallet wheel 32 is provided with a plurality of teeth 33 adapted to be engaged by teeth 34 and 36 formed at opposite ends of a cross member 37 of the pallet 19. The teeth on the pallet 19 and pallet wheel 32 are arranged such that on each oscillation of the pallet 19, the wheel 32 is rotated through the distance slightly greater than one-half of the angle subtended by the root of a tooth 33. Thus, referring specifically to the arrangements illustrated in FIGURE 1, upon counterclockwise rotation of the pallet 19, the tooth 36 engages the left side of a palletwheel tooth 33a and rotates the pallet wheel clockwise until the tooth 36 bottomsin a groove between the tooth 33a and the adjacent counterclockwise tooth. The rotation of the wheel is such that a tooth 33b on the pallet wheel 32 is now disposed clockwise relative to the tooth1'34 on the cross arm 37 of the pallet 19'. Upon subsequent clockwise rotation of the pallet 19, the tooth 34 engages the counterclockwise surface of the tooth 33!) causing the wheel to again rotate inaclockwise direction.

Thus, in a well-known manner, the pallet and pallet wheel cooperate to produce rotation of the pallet wheel in a given direction upon oscillation 'of the pallet about itspivot23l' 1 The construction of the apparatus may take the" form illustrated in FIGURE 2 of the accompanying drawings. In this figure, thereis provided a base plate 38 having formed therein a plurality of channels defining the fluid oscillator 1 and associated passages as indicated in FIG- URE 1. Referring again for the moment toFIGURE 1, itis apparent that theicross arm 37 of the pallet 19 and the pallet wheel 32 cannot lie in the same plane as the oscillator passages since these mechanical devices would destroy the continuity of the passages. In order to remove the mechanical elements from the plane of the oscillator, the pallet 19 is formed with a pair of oppositely directed right angle bends as illustrated in FIGURE 2 so that the arm 18 lies in the sector-shaped opening 17 in the plane of the oscillator while the cross arm 37 lies in a plane above, or as illustrated in FIGURE 2, to the right of the plane of the passages. The plate 38 is covered with a sealing layer 39 having only three openings formed therein. Two of the openings are to permit the shafts 23 and 30 to pass therethrough and ,a third opening, designated by the reference numeral 41, is in the form of a narrow slot and is employed to permit the passage of a short arm 42 connecting elements 18 and 37 of the pallet 19 to pass therethrough.

The elements thus far described are covered by a top or right side plate 43 as illustrated in FIGURE 2 and this may be appropriately sealed or bolted to the bottom plate 38 so as to maintain the layer 39 in sealing position relative to the various channels formed in the plate 43. The plate 43 is formed with a recessed region 44 to accept the portion of the pallet 19 which lies to the right of the plate 38 and the pallet wheel 32. It will be noted that the arm 42 has a relatively small angular movement due to its close proximity to the pivot point, the pivot shaft 23, of the pallet 19. Thus, the slot which must be formed in the sheet 39 is quite small and the amount of leakage between the sector-shaped region 17 and the region 44 formed in the plate 43 is minimal.

The pallet 19 and pallet wheel 32 may be formed from relatively thin stampings'and the arm 18 of the pallet is of a depth to substantially fill the sector-shaped region 17. This fact is not illustrated as such in FIGURE 2 wherein the arm 18 is shown to'be somewhat narrower than the depth of the passage 17. However, this has been done merely for ease of illustration and clarity of lines. It should be noted that a crown gear or intervalgear may be employed for the wheel 32.

In a practical embodiment, the shaft 33 will normally carry a gear 46 on one or the other end thereof, which gear is adapted to mate with a gear train to be driven by the apparatus of the present invention. Any mechanical means for detecting or utilizing the rotation of the shaft 33 may be employed. It is apparent also that rotation of the shaft 33 maybe converted to electrical impulses, if so desired, by means of conventional transducer techniques.

The apparatus of FIGURES l and 2 employs an oscillator having two output passages, and therefore the oscillator is capable of driving the pallet 19 in both clockwise and counterclockwise directions. Numerous types of pure fluid oscillators are known in the art today and any one of these may be employed so long as it has the requisite frequency stability and temperature insensitivity. One such oscillator which may be employed has only a single output channel. If, under special circumstances, it is desirable to use such an oscillator, the pallet 19 may be biased by a lightweight spring into a position covering or blocking the single output channel of the oscillator. In this case, the output fluid from the oscillator drives the vane or pallet arm away from the output passage when fluid is directed thereto and, when fluid is directed away from the single output passage, the vane is returned to its passage-covering position by means of the spring.

Instances may arise where the gear train driven by the gear 46 of FIGURE 2 imparts a relatively large inertia to the system. It may be that under these circumstances difficulties may be encountered in supplying suflicient energy to drive the-pallet 19 through complete arcs of rotation, as defined by the sides of the sector-shaped chan nel 17 in FIGURE 1, in the time between half cycles or switching of thestream of the oscillator 1. In such circumstances, the-arrangement of FIGURE 3 may be employed.

In the apparatus of FIGURE 3, there is provided a negativefeed-back*oscillator generally designated by the reference numeral "47 having a power nozzle 48, a pair of control orifices or nozzles 49 and 51 and a pair of outlet passages 52 and 53, respectively. The passages are separated" centrally by a divider 54 terminating at its downstream end in a concave wall 56. A vent 57 is located in the region centrally of the divider substantially touching the concave wall 56 at the downstream end of the vent. Extending between the passage 52 and the nozzle 49 is a first negative feedback path 58 and extending between the passage 53 and the control nozzle 51 is a second negative feedback channel 59. The oscillator employs a basic memory-type flip-flop, 'memory being provided by the position of the upstream apex of the divider 54 relative to the nozzle 48 and also by vortex-forming cusps 61 and 62 associated with the passages 52 and 53, respectively.

Located along the centerline of the device in the region downstream of the vent 54 is located a vane 63 pivoted about a shaft or other pivot mechanism 64. The vane 63 is of a general T-shape having a downwardly extending leg 66 and a cross member 67; the vane being symmetrical about a line through the pivot shaft 64 and the bottom of the leg 66. In the position of the apparatus illustrated in FIGURE 3, the vane 67 blocks communication between the passage 53 and its feedback passage 59.

In operation, if it is assumed that the fluid is flowing to the passage 52, the fluid proceeds through the feedback channel 58 to the nozzle 49 and produces switching of the power stream. The stream now issues out through the passage 53 and impinges directly upon the left side, as viewed in FIGURE 3, of the cross-arm 67 of the vane 63. The fluid which is directed against the vane 63 is diverted thereby into the vent channel 57, the force for moving the vane deriving from the momentum of the stream. The vane 63 begins to rotate clockwise, continued rotation thereof permitting fluid directed through the passage 53 to enter the feedback channel 59. As the vane 63- rotates clockwise, the size of the vent channel 57 available for egress of fluid from the region decreases, thereby insuring that a sufiicient flow is directed to the feedback channel 59 to eventually produce switching of the stream. The time delay introduced by the feedback channel 59 is at least such to permit the vane 63 to rotate fully clockwise before the power stream is switched. For clockwise rotation of the vane 63 blocks communication between channel 52 and the feedback passage 58 and the vent 57 is on the same side of the leg 66 as the passage 52. Upon switching, the stream impinges directly against the right side, as viewed in FIG- URE 3, of the cross arm 67 of the vane 63 and the vane is caused to rotate counterclockwise.

It is seen that the oscillator is essentially under the control of the vane 63 since feedback cannot commence until after all of the static inertia of the vane 63 and the total gear train has been overcome and the system has been put into motion. The necessary time delay in the passages 58 and 59 may be readily achieved by use of fluid inertances, resistances, and capacitances as the need arises.

The particular oscillator 47 illustrated in FIGURE 3 may be modified as indicated relative to the apparatus of FIGURE 1. Thus, any type of negative feedback oscillator may be employed, for instance, the vent passage 57 may be eliminated and individual vent passages for each of channels 52 and 53 may be provided as is conventional in the art. Again, if a single, output-passage, oscillator is to be employed then spring return may be employed on the vane 63.

The shaft 64 is caused to oscillate for it is secured to the vane 63. The shaft 64 may then carry a pallet which cooperates with a pallet wheel mechanism of the type illustrated in FIGURE 1. The pallet and pallet wheel in this modification may be completely mounted in a different plane from the channels of the oscillator so that there can be no interference therewith.

While I have described and illustrated specific embodiments of my invention, it will be clear that variation of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. A fluid-driven timing mechanism comprising a pure fluid amplifier having a power nozzle for issuing a power stream of fluid and a pair of output channels, means for periodically switching the power stream between said output channels, a pallet mounted for pivotal movement about a pivot, a rotatably mounted pallet wheel operatively associated with said pallet and means for oscillating said pallet about said pivot in response to alternating flow of fluid to said output channels so as to rotate said pallet wheel, wherein said means for periodically switching the power stream is independent of the position of said pallet.

2. A fluid-driven timing mechanism comprising a pure fluid flipflop having memory characteristics including a power nozzle for issuing a power stream of fluid and a pair of output channels, means for periodically switching the power stream between said output channels, a pallet mounted for pivotal movement about a pivot, a rotatably mounted pallet wheel operatively associated with said pallet and means for oscillating said pallet about said pivot in response to alternating flow of fluid to said output channels so as to rotate said pallet wheel, wherein said means for periodically switching the power stream is independent of the position of said pallet.

3. A fluid-driven timing mechanism comprising a pure fluid oscillator having a power nozzle for issuing a power stream of fluid, at least two output channels and feedback means for periodically switching the power stream between said output channels, a pallet mounted for pivotal movement about a pivot, a rotatably mounted pallet wheel operatively associated with said pallet and means for oscillating said pallet about said pivot in response to alternating flow of fluid to said output channels so as to rotate said pallet wheel, wherein said feedback means periodically 7 switches said power stream independently of the position of said pallet.

4. A fluid-driven timing mechanism comprising a pure fluid amplifier having a power nozzle for issuing a power stream of fluid and a pair of output channels, means for periodically switching the power stream between said output channels, a pallet mounted for pivotal movement about a pivot, a rotatably mounted pallet wheel operatively associated with said pallet and means for oscillating said pallet about said pivot in response to alternating flow of fluid to said output channels so as to rotate said pallet wheel, wherein said means for oscillating said pallet comprises a chamber having a pair of sidewalls, a leg of said pallet being located in said chamber for oscillation between said pair of sidewalls, first and second passages, each said first and second passages having One end extending into said chamber through different ones of said sidewalls and having the other end connected to different ones of said output passages.

5. The combination according to claim 4 wherein each of said first and second passages terminate in nozzles for directing fluid toward opposite sides of said leg of said pallet. t

6. The combination according to claim 5 further comprising a pair of vents extending into said chamber each through a different one of said sidewalls, recesses formed in opposite sides of said leg of said pallet, each said recess directing fluid from said nozzle formed at said one end of said first and second passages to said vent when said leg is juxtaposed to said sidewall of said chamber through which said nozzle and said vent extend.

7. The combination according to claim 6 wherein said means for periodically switching the power stream operates independently of the position of said pallet.

8. The combination according to claim 4 further comprising a pair of vents extending into said chamber each through a different one of said sidewalls.

9. The combination according to claim 4 wherein said fluid amplifier and said leg of said pallet lie in a first plane and wherein said pallet wheel lies in a second plane, and wherein said pallet further comprises a pair of teeth disposed on opposite sides of said pivot, said teeth extending into said second plane to contact said pallet wheel.

10. The combination according to claim 4 wherein said means for periodically switching the power stream operates independently of the position of said pallet.

11. A fluid-driven timing mechanism comprising a pure fluid amplifier having a power nozzle for issuing a power stream of fluid and a pair of output channels, means for periodically switching the output stream between said output channels, a pallet mounted for pivotal movement about a pivot, a rotatably mounted pallet wheel operatively associated with said pallet and means for oscillating said pallet about said pivot in response to alternating flow of fluid to said output channels so as to rotate said pallet; wherein said means for oscillating said pallet comprises a vane having a pair of arms, a rotatable shaft, means for securing said vane to said shaft so as to rotate said shaft upon rotation of said vane, one of said arms of said vane blocking one of said output passages when said vane is rotated to a clockwisemost position and the other arm of said vane blocking the other of said output passages when said vane is rotated to a eounterclockwisemost position, and means for securing said pallet to said shaft for oscillation therewith.

12. The combination according to claim 11 wherein said fluid amplifier comprises a fluid oscillator having a pair of feedback passages for receiving fluid in alternation from said output passages, said arms of said vane preventing fluid flow between one of said output passages and one of said feedback passages when in a clockwisemost position and preventing fluid flow between the other of said output passages and the other of said feedback passages when in a eounterclockwisemost position.

13. The combination according to claim 12 wherein said pure fluid oscillator further comprises a divider located 8 between and defining one wall of each of said, outputi passages, a vent located at the downstreamrend of said divider, said vane having a'leg, said leg being positioned when said vane is in one of said counterclockwise and said clockwise positions'to establish communication between said vent and an output channel blocked by an arrri of said vane and to prevent communication betweensaid vent and the other of said output channels. i 14. A fluid-driven timing mechanism comprising a pure fluid amplifier having a power nozzle forissuing a po'wer stream of fluid and a pair of output channels, means for cyclically switching the power stream between said output channels, a pallet mounted for pivotal movement "about'a pivot, a rotatably mounted pallet wheel operatively -a'sso' ciated with said pallet, and means foroscillating said pal let about said pivot in response to cyclical flow-offluid to said output channels so as to rotate said pallet wheel only ina predetermined direction, wherein said means for cyclically switching the power stream is independent of the position of said pallet. I I

15. A fluid-driven-timing mechanism comprising a pure fluid amplifier having a power nozzle for issuing a power streamjo'f fluid and a pair of output channels, a palle't mounted for pivotal movement ab'outa pivot, a rotatably mounted pallet wheel operatively associatedwith said,

pallet, and means for oscillating said pallet about said pivot in response to cyclical flow of fluid tosaid output passages so as to rotate said pallet wheel only in aqpredetermined direction, and means responsive to oscillation of said palletto produce cyclic flow of fluid 'to said output channels, wherein said means for oscillating said palletcomprises a vane having a pair of arms, a rotatable-shaft,- means for securing said vane to said shaft upon rotation of said vane, one of said arms of said vane blocking one of said output channels when said vane is rot atedto a clockwisemost position and the other arm of said vane blocking the other of said output channels when said vane is rotated to a eounterclockwisemost position, and means forv securing said pallet to said shaft for oscillation therewith."

16. The combination according to claim 13 wherein said fluid amplifier comprises a fluid oscillator having a pair of feedback passages for receiving fluid in alternation: from said output channels, said arms of said vane preventing fluid flow between one of said output channels and one of said feedback passages when in a clockwisemost position and preventing fluid flow between the other of said output channels and the other of said feedback passages when in a eounterclockwisemost position, and further comprising a divider located between and defining one wall of each of said output channels, a vent located. at the downstream end of said divider, said vane having a leg, said leg being positioned when said vane is in one of said counterclockwise and said clockwise positions to cs tablish communication between said vent and an output channel blocked by an arm of said vane and to prevent communication between said vent and the other of said output channels. 7

17. A fluid-driven timing mechanism comprising a'pallet mounted for pivotal movement about a pivot, a rotatablymounted pallet wheel operatively associated with said pallet, a pure fluid amplifier having a power nozzle for issuing a power stream of fluid and a pair of output channels, means for cyclically switching said power stream between said output channels, means responsive to cyclic fluid flow to said outlet passages for providing correspondingly cyclic oscillatory displacement of said pallet about said pivot so as to rotate said pallet wheel in only a predetermined direction, wherein said fluid amplifier and a portion of said pallet lie in a first plane and wherein said pallet wheel lies in a different plane, and wherein said pallet comprises a pair of teeth disposed on opposite sides of said pivot, said teeth extending into said second plane to contact said pallet wheel.

(References on following page) References Cited UNITED STATES PATENTS Woodward 137 8l.5 Warren et a1 137 81.5 Sewers 137-815 Scott 741.S X Hahl 58-42 Fischer 58--42 Etter 137625 .4

10 3,070,075 12/1962 Hanselmann 92-120 X 3,185,166 5/1965 Horton et al 137-815 M. CARY NELSON, Primary Examiner.

5 ROBERT C. MILLER, Assistant Examiner.

us. 01. X.R. ss-42; 91-3; 92-121

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