US1946559A

US1946559A - Dispensing device

Info

Publication number: US1946559A
Application number: US588743A
Authority: US
Inventors: Edwin C Weiskopf
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-01-25
Filing date: 1932-01-25
Publication date: 1934-02-13
Anticipated expiration: 1951-02-13

Description

3 Sheets-Sheet l umm 3; Mm MW if H u -QIH .l, llmlw wfiu m hfli lli INVENVTOR.

ATTORNEY E. c. WEISKOPF DISPENSING DEVICE Filed. Jan. 25, 1932 Feb. 13, 1934.

1934- E. c. WEISKOPF DISPENSING DEVICE Filed Jan. 25, 1932 3 Sheets-Sheet 2 INVENTOR. $4 M. (1

BY 7 ATTORNEY mm vlllidi 13, 1934- E. c. WEISKOPF DISPENSING DEVICE Filed Jan. 25, 1932 5 Sheets-Sheet 3 IN V EN TOR.

A TTORNEY AIM; C W- Patented Feb. 13, 1934 DISEENSENG DEVECE Edwin C. Weiskcpf, New York, N. Y.

Application January 2 5, 1932. Serial No. 588,743

19 Claims.

This invention relates to dispensing devices.

In making tests, as for example, in chemical or biological laboratories, it is often necessary to dispense small quantities of iquid at regular intervals for example, in the making of Wasserman tests.

This invention is directed to the provision of a simple, practical and effici nt machine for automatically ace mplishing this purpose.

An object of invention is to provide a machine of the character described, for repeatedly dispensing small quantities liquid, having means for adjusting the quantity of liquid dispensed, the construction the being such f rthermore, that the dispensed liquid may We. supply.

A further ob ect invention is to provide a motor operated practical and .gged por able a achine of the character described, whi

shall be inexpensive to manufacture, smooth, ac-

curate and positive in operation, easy to assemble, control and and yet efiicient to a high degree.

Other objects of tlie invention will in part be 1 obvious and in part .ereinafter pointed out.

The invention accord igly consists in the features of construction, combinations of elements, and arrangement or" parts which will be exemplilied in the construction hereinafter described, 3 of which "he scope of application will indicated in he following claims.

In the accompanying drawings, in which is shown of the various possible illustrative embodiments of this invention,

Fig. l is a side elevational view of a machine embodying the invention with a side wall thereof removed;

Fig. 2 is a top plan view of the structure shown in Fig. 1;

r Fig. is a fragmentary cross-sectional View taken on lin 3-3 of Fig. 2;

Fig. 4 is a partial cross-sectional view taken on line 4-4 of Fig. 3;

. 9 is a vf w on a smaller e scale, similar to showing another position of the parts;

(Q1. fil -103) Fig. 1G is a cross-sectional View taken on line 1010 of Fig. 3.

Referring now in detail to the drawings, 10 designates a machine embodying the invention here shown in the form of an automatic pipette device adapted to dispense small cuiantities of liquid at regular intervals. The machine 10 comprises a portable prismatic box 11 adapted to rest on a table or like support. The box 11 comprises a bottom wall 12 and a top wall 13 interconnected by pairs of posts 14 and i5, and 16 and 17 respectively, located at the front and rear ends of the box. A front wall 18 may be attached to the

front posts

14 and 15, and a rear wall 19 may be attached to the

front posts

16 and 17. The box may furthermore be provided with perfora-ted.

side walls

22 and 23.

Mounted on the top wall 13 adjacent the front end of the box, is a member 25 having a flange portion 26 contacting the upper surface of said top wall, and an upstanding tubular sleeve portion 27, open at the upper end thereof, and formed with a pair of aligned notches 28 and 29 in the upper edge thereof. The member 25 may be attached to the top wall 13 by means of screws 39, or in any other suitable manner. Removably mounted within said sleeve portion 27 is a valve housing 32 comprising a cylindrical portion 33 having an inner tapered or conical surface 34, and formed with an outwardly extending horizontal short pipe or tube 35 on one side thereof, having a passage 36 communicating with the interior of the housin Said housing is further formed with a pair of aligned outwardly extending pipes or tubes and 39 extending outwardly from the opposite side thereof, and with

passages

38a and 39a, respectively, communicating with the interior of the housing. It will be noted that the tube 35 engages within the notch 29 of the tubular wall 27, and the lower tube 39 engages within the notch 28 of said tubular portion. whereby said Valve housing 32 is retained against rotary movement with respect to the member 25. A thumb screw so fixed to valve portion 33 is adapted to engage a notch 40a formed in the upper edge of cylindrical wall 27 and a thumb screw 41 screwed to the outer end of said screw is adapted to press against the outer surface of said wall to releasably retain said member 32 against removal from member 25, Obviously, upon loosening the thumb screw, the member 32 may be lifted from said tubular member 27.

Rctatably mounted within the tubular member 33 is a tapered or frusto-conical valve or cock 42 having a flange 43 contacting the bottom edge of said tubular portion 33. The upper end of said valve is formed with an annular groove 42a, and a semi-circular member 422) pivoted to the upper end of the housing portion 32 is adapted to engage within said groove to prevent axial movement between said valve member and housing. The valve 42 is preferably provided with a pair of transverse inclined through passages 44 and 45 so arranged that in one angular position of said valve, the passage 44 interconnects the passage 36 with the passage 39a, and in another position of said valve, the passage 45 interconnects the passage 36 with the passage 38a. The flange 43 is provided with a segmental cut away portion or notch 46, and a pin 47 secured to the lower edge of the tubular portion 33 projects into said notch, said notch being so arranged that upon oscillating the valve 42, the limits of oscillation of said valve will bring the passages 44 and 45, respectively, in communication with the passage 36. Attached to the tubular portions 38 and 39 are rubber tubes 56 and 51 respectively, serving respectively as outlet and inlet tube, as will appear more fully hereinafter.

For the purpose hereinafter described, there is fixed to said top wall 13 of the box 11, an elongated longitudinal guide member 54 having an inverted T-shaped slot 55 aligned with the tubular portion 35 of the valve housing 32. Slidably mounted on said guide member is a member 56 having a portion 57 extending within said slot, and a wall 58 extending upwardly therefrom. Fixed to said portion 57 is a vertical upwardly extending screw 59. A washer 66 having a central opening receiving the upper end of the screw is adapted to extend beyond the slot 55 so that portions of the washer may contact the upper surface of the guide member 54. A screw threaded member 61 screwed to the upper end of the screw 59 is adapted to be turned by a handle 62 for pressing the washer against the upper surface of the guide member to fix the member 56 to said guide member in various adjusted positions. Attached to the upper end of the upstanding wall 58 is a forwardly extending flaring or conical shaped member 63 having a radial slot 64, the upper end of said wall 58 being formed with a slot 65 registering with slot 64 and extending to the center of said conical shaped member.

Mounted on and between said member 56 and said tubular portion 35 is a syringe or similar pumping device 68, comprising a barrel 69 having a tubular portion 70 preferably made of glass or the like transparent material. Attached to the forward end of the tubular member 70 is a metal tip '71 having a forwardly projecting por tion '72 adapted to be received within a passage 35a of said tubular portion 35. At the rear end thereof, the tubular member 70 is provided with a metal collar 73 adapted to be received within and contact the flaring portion 63 of the member 56. Slidably mounted within the glass tube '70 is a plunger '75 having a piston portion 76 and an elongated stem 77 extending rearwardly through the rear end of the barrel and through the slots 64, 65. The stem 77 is adapted to pass through the slots 64 and 65, whereby the syringe may be axially aligned with the tubular portion 35 of the valve housing and the axis of the conical portion 63 of said member 56. By properly manipulating the handle 62, the member 56 may be slidably moved into contact with the collar 73 and then fixed in the position for rigidly holding the barrel 69 against movement. To remove the syringe, the handle is turned for loosening washer 60, the member 56 slidably moved rearwardly and the barrel '70 retracted until the tip '72 is extracted from tube 35. The stem '77 may then be moved out of slots 64, 65.

It will now be seen that with the valve 33 in the position shown in Fig. 3, movement of the plunger '75 forwardly will expel any liquid within the barrel through the passage 45 and through the outlet tube 50. With the parts however in the position shown in Fig. '7, retraction of the plunger will cause a suction for drawing liquid through the inlet tube 51 and passage 44 into the barrel. The free end of the tube 51 may be placed within any suitable supply of liquid.

For pumping sinal quantities of liquid from said supply at regular intervals, means is provided for alternately reciprocating the plunger and oscillating the valve 42 so that with the valve in one position, the plunger may be re tracted for drawing liquid from the supply into the barrel, and thereafter upon oscillating the valve, communication between the supply and the barrel is cut off, and communication established between the barrel and the outlet pipe and upon thereafter causing forward movement of the plunger the liquid in the barrel is expelled.

, To this end there is mounted within the box 11, and on the bottom wall 12 of said box, an electric motor 80 adapted to be supplied with current by means of wires 81 connected to a plug 82 mounted on the rear wall 19, to which a socket 83 connected to any suitable supply of current may be detachably attached. Any suitable switch 84 may be interposed in the wires 81, for controlling the motor 86. The latter may be provided with a central horizontal shaft 85 having a worm 86 thereon, said worm meshing with a worm wheel 87 carried on a shaft 88, having a worm 89 thereon. The worm 89 i adapted to mesh with a worm wheel 99 carried on a vertical shaft 91.

Attached to the upper end of the shaft 91 is a cylindrical clutch member 92 having a plurality of similar peripheral notches or cut away portions 93. Supported by said member 92 is a second clutch member 94 having a flat annular disc portion 940. and a downwardly extending cylindrical skirt portion 95 rotatably receiving said portion 92. To the lower end of said portion 95 there is attached an annular ring 96 contacting the underside of said member 92.

Disposed within each notch 93 and between the skirt portion 95 and said member 92 is a roller 97. The notches 93 are similar and each is shaped to provide an inclined surface 98 and a radial surface 99. Each of said surfaces 99 is provided with a socket 100 housing a small coil compression spring 191 adapted to press the roller 97 between the surface 99 and the inner surface of said skirted portion 95.

Thus, when the motor is running, the clutch member 92 will be rotated in a clockwise direction looking at Fig. 10. During operation of the motor, the rollers 97 will be wedged between the

clutch portions

92 and 95 so that the clutch member 94 will be rotated by said motor. The clutch member 94 however, may be rotated in a clockwise direction, without rotating shaft 91 or turning the motor. During such rotation of the clutch member 94, the rollers 97 will be moved against the surface 99 to release the clutch member 92 from the cylindrical clutch portion 95.

Attached to the underside of the disc 94a is an eccentrically disposed flat circular member or disc 103. Disposed about said disc 103 is a ring 104 having an arm 105 extending radially therefrom. The ring 104 is retained in contact with the underside of the disc 940. by means of washers 106 attached to the underside of the circular member 103 and underlapping said ring. The arm 105 extends toward the front of the box, and fixed to the free end of said arm is an upstanding pin 107. For the purpose hereinafter appearing, there is rotatably mounted at the underside of the top wall 13, a rotary disc 109 supported by a screw 110 screwed to the underside of said top wall and having a head contacting the underside of said disc. The pin 107 is pivoted to said disc 109 at a point spaced from the center thereof, so that upon operating the motor to rotate the disc 94a, the disc 109 or will be oscillated by action of the eccentric ring 104 and crank arm 105.

Said disc 109 is formed at the edge thereof with an inwardly curved notch 112; and attached to the underside of said disc is a ramal lug 113 extending beyond said notch and having a vertical pin 114, extending upwardly and disposed somewhat beyond the periphery of said disc 109. Fixed to the underside of said top wall 13 and beneath the valve 42 is a bracket 115 having a portion 116 spaced from and parallel to the underside of said top wall. Said top wall is formed for the purpose hereinafter appearing, with an opening 117 coaxial with sm'd valve 42 and the portion 116 of the bracket 115 is formed with an opening 118 aligned with said opening 117. Rotatably mounted between the underside of said top wall 13 and said portion 116 of the said bracket, is a Geneva gear member 110 having a downwardly extending pin i 120 journaled in said opening 118. Fixed to said curvature of the periphery of the disc 109 on opposite sides of said slot 128.

It will be now be understood that as the motor operates and the disc 109 is oscillated first in one direction, the pin 114 will engage within the slot 128, the slotted portion of said gear entering notch 112 during this action. When the disc 109 is oscillated in the opposite direction, the pin 114 again enters the slot 128 and rotates the Geneva gear 119 in the opposite dim rection, so that said gear is oscillated; and due to the engagement of the slotted pin 121 with the transverse pin 124, the valve 42 is likewise oscillated. The parts are so proportioned that oscillation of the valve 42 will be limited by the pin 47 and the segmental notch 46 to bring the valve in the positions shown in Fig. 3 and Fig. 7 for the purpose above described.

For the purpose of reciprocating said plunger 75, the top wall 13 is formed adjacent a side edge thereof and substantially midway between the ends thereof, with a circular opening 130 receiving the shank 131 of a block disposed beneath said top wall. Said shank is formed with a screw threaded opening receiving the shank 132 of a screw 133 having an enlarged head contacting the upper surface of said top wall for pivoting said block to said top wall. An elongated curved segmental plate 134 is fixed adjacent one end thereof, to the underside of said block 135, said plate being parallel to said top wall and extending toward the opposite side edge thereof. Attached to the said plate at substantially the mid-portion thereof, is a lug 136 extending forwardly therefrom, and interconnecting said lug with the disc 94a, as at 137 and 138, is a link 139 whereby said plate 134 may be oscillated about one end thereof when the disc 94a is turned. Slidably mounted on said plate 134 is a member 142 having portions engaging the edges of said plate, and an upstanding pin 143. The plate 134 is provided with an upstanding wall 144 at the free end. thereof, and rotatably and nonslidably mounted on and between the block 135 and said wall 144, is an elongated screw 145 having a square shaped end or nut portion 146 extending beyond said block 135. A member 148 having a screw threaded opening 149 receiving the screw 145 therethrough, is provided with a pair of bifurcated arms 150 forming a slot slidably receiving said pin 143. Said member 1481s prevented from rotation by contacting a portion of the member 142.

It will now be noted that upon engaging the portion 146 of the screw with a suitable wrench and turning said screw, the member 148 will be caused to slidably move along the screw, and due to the engagement of the former with the pin 143, the member 142 will be caused to slide along the curved plate 134. Pivotally attached to the underside of said member 142 is a link 153 extending rearwardly therefrom, and attached to the free end 154 of said link is a pin 155 extending upwardly therefrom.

For the purpose hereinafter appearing, the guide member 54 is formed with an elongated slot 155a, and the top wall 13 is formed with an elongated slot 156 registering with said slot 155a. Slidably mounted on said guide member is a member 157 to which there is attached a screw 158 having socketed portion 159 extending downwardly through said slots 155a, 156, and pivotally receiving the upper end of the pin 155. It will now be understood that as the plate 134 is oscillated, the member 157 due to the connection thereof with the link 153, will be reciprocated on the guide member 54. It will be further understood that the stroke of the member 157 may be adjusted by means or" the screw 145. Thus upon turning the screw to bring the plate 142 closer to the outer end 144 of the plate 134, the stroke will be increased. Upon turning the screw 145 to bring the member 142 closer to the pivoted end of said plate 134, the stroke of said member 157 will be decreased. The curvature of the plate 134 is obtained by describing an arc with the pin 155 as a center. With such construction, the pin 155 will be brought back to the same point during each oscillation of plate 134, no matter to what position the member 142 may be moved tubular portion 164. The tubular portion 164 is adapted to slidably receive the stem 77 of the plunger 75, and a set screw 165 at one end of said tubular portion is adapted to attach said stem to said tubular portion. It will now be understood that the plunger may be reciprocated due to the attachment thereof to the member 157 which may be reciprocated by the link 153.

The operation of the device will now be described. With the valve housing 32 and the valve 42 mounted on the member 25, the stem '77 of the plunger may be first inserted within the tubular portion 164 of the member 157 and then swung about the pin 161 to bring the stem through the slots 64 and 65 of the members 58 and S3. The barrel 69 is then moved to bring the tip 72 within the tubular portion 35, and the member 56 may then be slidably moved forwardly until the flaring portion 63 contacts the rear 001- lar '73. The handle 62 may then be manipulated to fix the member 56 on the guide member 54. The plunger '15 may then be pushed to bring the piston 76 against the tip 72. The disc 94a may then be turned by hand to the position shown in Fig. 4. In such position, the curved plate 134 is at the forward limit of its angular movement, and the pin 155 is in the most forwardly position thereof. The disc 94a preferably extends somewhat beyond a side edge of the top wall 13 to permit hand manipulation of said wheel, and a mark 170 may be placed on the wheel with the numeral 1 adjacent said mark to indicate the position of the disc when the plunger is in the full forward position thereof. The screw 165 may then be tightened for fixing the stem 77 to the tubular portion 164. The disc may then be rotated by hand for causing pivotal movement of the plate 134 rearwardly to move the member 157 rearwardly. The disc 94a is so rotated until the rearward limit of angular travel of the plate 134 is reached. The disc may be formed with a mark 171 and with a number 2 adjacent said mark to indicate said rearward limit of angular movement of said plate 134. During the latter movement, the plunger will have been moved with the member 157 away from the tip '72 of the syringe. The screw 145 may then be turned by use of a suitable wrench engaging the: nut portion 146 to bring the piston to any desired position. For example if it is desired to pump or dispense .5 c. c.

- of liquid at regular intervals, the screw is turned to bring the outer end of the plunger to the mark .5 c. 0. indicated on the tubular portion of the barrel, said barrel being suitably graduated for this purpose.

It will be noted that the member 157 moves forwardly or rearwardly during the turning movement of the screw 145 to bring the piston to the proper position. The motor may thereafter be started for operating the machine and the proper amount of liquid to which the syringe has been set will be dispensed for each reciprocation of the piston.

The valve 42 is oscillated at the ends of the strokes of the piston. Thus, adjacent the end of the expelling stroke of the plunger with the parts as shown in Figs. 3 and 4, the disc 109 will cause oscillation of the valve 42 to change the position thereof so that when the intake stroke of the piston starts the valve will be in the position shown in Fig. '7. It will be noted that a line from the pivotal point 138 to the center of the disc 94a is at right angles to a line from the center of said disc 94a. to the center of the disc 103 so that when there is least movement of the piston, there is greatest movement of the disc 109. In other words, when the plunger and the curved plate 134 to which it is connected, are at the ends of the strokes thereof, the disc 109 is at the mid-point of its oscillation.

It will be noted that the wrench 180 which receives the nut 146 for rotating the screw 145 may be mounted on a suitable pin fixed to the end wall 19 so as to be handy when necessary for use. A pointer 181 may be fixed to a side edge of the top wall 13 to permit the marks 170 and 171 to be read. The front wall 23 is provided with cut out portion or opening 182 to permit the extending edge of the disc 94a to pass therethrough. Said side wall 23 may be reinovably attached to the posts by means of thumb screws 183 to give access to the interior of the box. The other perforated side wall 22 is likewise provided with a cut out portion or opening 184 to permit the nut portion 146 of the screw 145, and the adjacent end of the plate 134 to extend therethrough.

It will thus be seen that there is provided a device in which the several objects of this invention are achieved and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. A machine of the character described, comprising in combination, an electric motor, pump means including a piston, actuated by said motor for dispensing equal quantities of liquid at regular intervals, and means for adjusting said quantities of liquid, said last means including means for changing one end point only of the stroke of said piston.

2. In combination, a barrel, a plunger therein, an inlet conduit and an outlet conduit, a valve having passages adapted to selectively connect the inlet and the outlet conduits with the interior of said barrel, and means for alternately reciprocating said plunger and rotating said valve, and means for adjusting the length of the stroke of said plunger without changing one of the end points of the stroke of said piston.

3. In a machine of the character described, a base plate, a tubular valve housing mounted thereon, a valve rotatably mounted within said housing, said housing being provided with three passages communicating with the interior thereof, said valve having a pair of openings therein adapted to selectively connect one of said passages with each of the other of said passages respectively, a pumping device connected to the first of said passages including a barrel and plunger, and means for actuating said plunger and rotating said valve at the end only of each stroke of said plunger.

4. In combination with an inlet and an outlet pipe, means for drawing liquid through said inlet pipe and expelling the same through said outlet pipe periodically in equal amounts, said means comprising a valve and a pump and means for alternately actuating said pump and said valve, said pump comprising a motor, a piston operatively connected to said motor and adapted to be reciprocated thereby. and means for adjusting the length of stroke of said piston without changing one end point of the stroke of said piston.

5. In combination with a rotary valve and a pumping means including a reciprocating member, means for rotating said valve and reciprocating said member, said means comprising a member rotatable with said valve, a second member adapted to engage said reciprocating memher, and means associated with said second member for rotating said rotary member, said means comprising a rotatable plate, an electric motor and a one-way clutch connecting said motor and said rotatable plate.

6. A pipette machine comprising a basa'a valve housing fixed thereto, said housing having an outlet passage and an inlet passage, and a third passage communicating with the interior thereof, a rotary valve mounted within said housing having at pair of passages adapted to selectively connect said third passage with said inlet passage and outlet passage, a syringe comprising, a graduated barrel having an opening communicating with said third passage, a plunger within said barrel and means for reciprocating said plunger and oscillating said valve, and means for adjusting the length of the stroke or" said plunger, said means permitting the plunger to be moved to a predetermined point in the barrel during reciprocation irrespective of said adjustment.

'7. A pipette machine comprising a base, a valve housing fixed thereto, said housing having an outlet passage and an inlet passage, and a third passage communicating with the interior thereof, a rotary valve mounted within said housing having a pair of passages adapted to selectively connect said third passage with said inlet passage and outlet passage, a barrel having an opening communicating with said third passage, a plunger within said barrel and means for reciprocating said plunger and oscillating said valve, said means comprising an electric motor, a disc to be rotated by said motor, a second disc rotatably mounted on said base, eccentric means interconmeeting said discs for oscillating said second disc, means cooperating with said second disc and valve for oscillating the latter, a member pivotally mounted on said base, a link interconnecting said pivoted member with said first disc for oscillating said pivoted member during rotation of said first disc, a member slidably mounted on said base and fixed to said plunger, and a link interconnecting said slidably mounted member with said pivoted member.

8. A pipette machine comprising a box having a bottom wall and a top wall, a syringe comprising a barrel mounted on said top wall, and a plunger slidably mounted in said barrel, a member having an inlet passage and an outlet passage, a valve having means for selectively interconnecting the outlet end of said barrel with said inlet passage and outlet passage, and means for reciprocating said plunger and oscillating said valve, said means comprising an electric motor mounted on said bottom wall, a vertical shaft connected by reduction gearing to said motor shaft. a member having a clutch connection to said shaft adapted to be rotated by said shaft in one direction, means operatively interconnecting said member and said valve for oscillating the latter as member is rotated by said motor, and means interconnecting said member with said plunger for reciprocating the latter as said member is rotated.

9. In a machine of the character described, a support, a syringe comprising a barrel mounted on said support, a plunger within said barrel, and means for reciprocating said plunger, comprising a rotary member, a member pivoted directly to said support,a link interconnecting said rotary member said pivoted member for osc'illating the latter as said rotary member is rotated, a member slidably .iounted on said pivoted member, and a link interconnecting said slidably mounted member with said plunger.

10. In a machine of the character described, a support, a syringe comprising a barrel mounted on said support, a plunger within said barrel, and means for reciprocating said plunger, comprising a rotary member, a member pivoted directly to said support, a link interconnecting said rotary member and said pivoted member for oscillating the latter as said rotary member is rotated, a member slidably mounted on said pivoted memher, a link interconnecting said slidably mounted member with said plunger, and means for causing sliding movement of said slidably mounted member f or changing the stroke of said plunger.

11. In a machine of the character described, a support, a syringe comprising a barrel mounted on said support, a plunger within said barrel, and means for reciprocating said plunger, comprising a rotary member, a member pivoted to said support, a link interconnecting said rotary member and pivoted member for oscillating the latter as said rotary member is rotated, a member slidably mounted on said pivoted member, a link interconnecting said slidably mounted member with said plunger, and means for causing sliding movement of said slidably mounted member for changing the stroke of said plunger, said pivoted member having the curvature of an arc described with a radius having the length of said last link, whereby said plunger may be moved to a predetermined position at the end of one of its strokes in all adjusted positions or said slidably mounted member. 12. A pipette machine comprising a portable box having a bottom wall and a top Wall, a syringe comprising a barrel, mounted on said top wall, and a plunger mounted therein, a valve housing mounted on said top wall having an outlet passage and an inlet passage, and a third passage communicating with the outlet end of said barrel, a rotary valve mounted within said valve housing having a passage adapted to connect said inlet passage with the outlet end of said barrel in one position of said valve, and a second passage for connecting said outlet passage with the outlet end of said barrel in another position of said valve, and means for reciprocating said plunger and rotating said valve, said meanscomprising an electric motor mounted within said box on said bottom wall, a vertical shaft rotatably supported by said motor, reduction gearing interconnecting the motor shaft with said vertical shaft, a rotary ember having a clutch connection to said Vertical shaft, a member rotatably mounted on said top wall, crank means interconnecting said rotary member udth said rotatably mounted member for oscillating the latter as said rotary member is rotated, a member mounted on said top wall for rotation with said valve, havinga Geneva gear connection to said rotatably mounted member, a member pivoted to said top wall, a link interconnecting said rotary member with said pivoted member, a member slid-ably mounted on said pivoted member, a second member slidably mounted on said top wall and connected to said plunger, and a link interconnecting said first slidably mounted member with said second slidably mounted member and a second passage for connecting said outlet passage with the outlet end of said barrel in another position of said valve, and means for reciprocating said plunger and rotating said valve, said means comprising an electric motor mounted within said box on said bottom wall, a vertical shaft rotatably supported by said motor, reduction gearing interconnecting the motor shaft with said vertical shaft, a rotary member having a clutch connection to said vertical shaft, a member rotatably mounted on said top Wall, crank means interconnecting said rotary member with said rotatably mounted member for oscillating the latter as said rotary member is rotated, a member mounted on said top wall for rotation with said valve, having a Geneva gear connection to said rotatably mounted member, a member pivoted to said top wall, a link interconnecting said rotary member with said pivoted member, a member slidably mounted on said pivoted member, a second member slidably mounted on said top wall connected to said plunger, a link interconnecting said first slidably mounted member with said second slidably mounted member, and means for causing sliding movement of said first slidably mounted member along said pivoted member.

14. A pipette machine comprising a portable box having a bottom wall and a top wall, a syringe comprising a barrel, mounted on said top wall, and a plunger mounted therein, a valve housing mounted on said top wall having an outlet passage and an inlet passage, and a third passage communicating with the outlet end of said barrel, a rotary valve mounted within said valve housing, having a passage adapted to connect said inlet passage with the outlet end of said barrel in one position of said valve, and a second passage for connecting said outlet passage with the outlet 1 end of said barrel in another position of said so necting the motor shaft with said vertical shaft,

a rotary member having a clutch connection to said vertical shaft, a member rotatably mounted on said top wall, crank means interconnecting said rotary member with said rotatably mounted member for oscillating the latter as said rotary member is rotated, a member mounted on said top Wall for rotation with said valve having a Geneva gear connection to said rotatably mounted member, a member pivoted to said top wall, a link interconnecting said rotary member with said pivoted member, a member slidably mounted on said pivoted member, a second member slidably mounted on said top wall connected to said plunger, a link interconnecting said first slidably with said second slidably mounted member, and means for causing sliding movement of said first slidably mounted member along said pivoted member, said pivoted member being curved and the curvature of an arc described by a radius equal to the length of said second link.

15. In a machine of the character described, a support, a tubular member fixed thereto, a tubular valve housing attached to said tubular member, said valve housing havin a tapering bore and a pair of tubular portions extending from one side thereof ,and a third tubular portion extend ing from another side thereof, a rotary tapering valve rotatably mounted within said valve housing, and having a pair of passages adapted to selectively connect said third tubular portion with each of said pair of tubular portions, a member slidably mounted on said support having a conical portion formed with a radial slot, a syringe comprising a barrel having the forward end thereof connected to said third tubular portion, and the rear end thereof engaging said conical portion, and a plunger slidably mounted within said barrel and having a stem extending through said slot, a second member slidably mounted on said support, a member pivoted to said second slidably mounted member and having a tubular portion receiving said stem therethrough.

16. In a machine of the character described, a base, a tubular member fixed thereto, a tubular valve housing having a portion slidably received within said tubular member, means for fixing said member to said tubular member, said housing having a pair of tubular portions extending in one direction, and a tubular portion extending in another direction, a tapered rotary valve mounted within said tubular housing having a pair of passages adapted to selectively interconnect said third tubular portion with each of said pair of tubular portions, said rotary valve having a flange formed with a segmental notch, a pin fixed to said valve housing extending into said notch for limiting rotary movement of said valve, and means for causing rotation of said rotary valve, said means comprising a member rotatably mounted on said support, means for oscillating said member, said valve being formed v ith a socket and a pin traversing said socket, and a pin fixed to said member extending into said socket, and provided with a slot receiving said first pin therethrough.

17. In a machine of the character described, a base, a tubular member fixed thereto, a tubular valve housing having a portion slidably received within said tubular member, means for fixing said member to said tubular member, said housing having a pair of tubular portions extending in one direction, and a tubular portion extending in the opposite direction, a tapered rotary valve mounted within said tubular housing having a pair of passages adapted to selectively interconnect said third tubular portion with each of said pair of tubular portions, said rotary valve having a flange formed with a segmental notch, a pin fixed to said valve housing extending into said notch for limiting rotary movement of said valve, and means for causing rotation of said rotary valve, said means comprising a member rotatably mounted on said support, means for oscillating said member, said valve being formed with a socket and a pin traversing said socket, and a pin fixed to said member extending into said socket, and provided with a slot receiving said first pin therethrough, said rotary valve being formed with an annular groove, and a curved member pivoted to one end of said tubular housing adapted to be moved into said groove for preventing axial movement of said rotary valve with respect to said valve housing.

18. In a pipette machine, a syringe comprising a graduated barrel and a plunger slidably mounted therein, a valve housing having an outlet passage and an inlet passage and a third passage communicating with the outlet end of said barrel, a rotary valve within said housing having a passage adapted to connect said inlet passage with the outlet end of said barrel in one position of said barrel, and a second passage for connecting said outlet passage with the outlet end of said barrel in another position of said valve, and means for reciprocating said plunger and third passage, a member slidably mounted on said base and adapted to engage the rear end of said barrel, a plunger slidably mounted within said barrel and projecting from the rear end of the latter, a rotary valve mounted within said valve housing and having passages adapted to selectively connect said third passage with said inlet and outlet passages, a member slidably mounted on said base and attached to said plunger and means for reciprocating said last mentioned slidacle member and oscillating said valve.

EDWIN C. WEISKOPF.