DE2558063C2 - Liquid pump for a writer - Google Patents

Description

To drive the piston 6, a shaft 10 that is mounted in a housing 9 is mounted so as to be rotatable

^fl ° gear 11 is provided. In the gear 11 there is provided a groove 12 which is adapted to the desired movement of the piston 6 and in which an actuating member fastened to the piston rod 7, consisting of a roller 14 rotatable about a shaft 13, runs. The gear 11

'' 5 is driven by a pinion 15 driven by a motor 16 is driven, driven. A plastic membrane 8, which forms the pump housing, is seated on the piston rod 7 4 separates sealingly from the drive means

The piston 6 is molded from a single piece of plastic. At its free end there is a recess 17 present, so that the piston outer wall 18 forms a sleeve 19. The cylinder space 20 is for Inflow for the writing ability widened step-shaped in its cross-section. Furthermore, in the Feed line 23 to the writing fluid container 2 a capillary tube 24 z. B. arranged from glass.

The membrane 8 and the sleeve 19 of the piston 6 also work as an intake valve In the space 35 in front of the cylinder 5 κ .a :: gL There is also a gap 27 twisting the end face 25 of the cuff 19 and de. .. I. ^ r-i'.oberfläche 26 eibf the inflow of SCKI ''. ^"1 S, _o ness allowed into the cylinder chamber 20 by '* .i existing JJnterdruckim cylinder space TOV · α from the Schreibflüssigizlceit: BehäJter 2 : through: da & - ^l ^ ,; »iIIarrohir24: through, ^ through the gap 27 and into the cylinder space 20 - suck in:

EZJ3ie ~ Niit J2 is designed in such a way that the piston moves closer to the door than it moves forward. This is done, so that the pumping work is carried out during the major part of a three-way rotation _{: of} the ^ -gear wheel IV ₁ and -in addition, so that the pressure vessel is kept during filling: the pump -Jo low as possible wifd _L

- When the piston 6 moves forward, it lays down ijthe outer wall lender cuff 19 "because of the im Sealing cylinder space 20 occurring overpressure to the cylinder inner surface 26 and prints the writing fluid from the cylinder space 20 to Clerk 3 out. The liquid then passes through the line 28 and pushes the spring-loaded valve 29 back

s and arrives at recorder 3 via connection 30.

The unused liquid flows back to the container 2 via the line 31. The valve 29 is supported by a screw 32 with a hole 32 '.

There is also a receptor 33 which is used to regulate the pressure.

ι. present. The receptor 33 is against by means of springs 22 a space 34 pressed in the liquid system, which is closed by a membrane 33a in the Backward movement of the piston 6 largely compensates for a drop in pressure.

i> The plastic membrane 8 follows the movement of the Piston 6. When the piston 6 or the membrane 8 moves forward, the space 35 between the Membrane 8 and the cylinder 5 and in the capillary tube 24 an overpressure, the in the supply line 23 or the im

2'j_. Kapülarrohr 24 existing air bubbles upwards: ^ J are pressed. During the backward movement of the membrane 8, air and ink are sucked in, so that the pump system gradually fills up with no ink.

^ This will give you after a few pumping processes

j = -: an air-free filling of writing fluid in the pump

- and writing system.

~~~~ - By the drive means 7 and 9 to 16 and the i: ^ training of the piston 6 or the cylinder 5 can

- ^ Writing fluid can be pumped out to very high pressures. The piston 6 is also designed so ^{: z:} £ that it od without the aid of piston rings. can seal against a cylinder wall.

1 biatc drawings

Claims (7)

Patent claims: 1. Liquid pump for conveying writing liquid from a liquid container to a pen, with a pump housing with a cylinder and a piston, and means for Forward and backward movement of the piston in the cylinder, characterized in, that the piston (6) is formed from a single piece of plastic, with the one at its free end a recess (17) is present so that the piston outer wall (18) forms a sleeve (19), whose wall thickness is dimensioned so that they are in the forward movement of the piston (6) to the The inner surface of the cylinder (26) is sealingly applied and the writing fluid is removed from the cylinder space (20) to the recorder (3) pushes out, and that the piston diameter is chosen so that the Backward movement of the piston (6) between the end face (25) of the sleeve (19) and the Cylinder inner surface (26) has a gap (27) which allows writing fluid to flow into the cylinder space (20). 2. Liquid pump according to claim 1, characterized characterized in that the pump housing (4) by a plastic membrane placed around the piston rod (7} (8) is sealed, which moves depending on the piston movement 3. Liquid pump according to claim 1 or 2, characterized in that for the movement of the piston (6) egg motor-driven wheel (11) is provided, in - "" em one of the desired movement of the piston (6) adapted groove (12) is arranged in which an actuator (13,14) attached to the piston rod (7J) runs. 4. Liquid pump according to claim 2, characterized in that in the supply line (23) to the Writing fluid container, a capillary tube (24) is arranged. 5. Liquid pump according to claim thereby characterized in that the capillary tube (24) is a glass tube 6. Liquid pump according to one of claims 1 to 5, characterized in that the BewegungsiTiiUei (7.9 to 16) for the piston (S) are designed so that the piston (6) moves back faster than moved forward. 7. Liquid pump according to one of claims 1 to 6, characterized in that in the liquid system there is a space (34) which is closed by a body (33a) pressed resiliently in the direction of the interior of the space (34) hen in the fact that it is complicated in structure and that the pumping action deteriorates over time due to the decreasing spring action Due to the metal piston, there is high wear * on both the piston and the cylinder. From GB-PS 14 02 020 a pump for a writing instrument is known, the two arranged in parallel Has cam disks which each actuate a piston. A motor-driven disc is used as the valve ίο with cutouts that uses the flow of liquid controls This pump is also under construction complicated and expensive as well as failure-prone. In the DT-OS 17 28 474 is a single-acting manually operated piston pump for dosing 'Described for example 5 cosmetic products with ^e: is provided nem operating in the pump cylinder spring-loaded piston of the way of the spring to a valve acting Because of the decreasing spring effect allows the pumping action and the tightness of the valve with time. In CH-PS 5 50 940 a pump for conveying viscous material is described. The piston of this pump consists of several parts, which would be very complicated in the case of a piston for a liquid pump of the type mentioned, which is small in structure. The invention has for its object to provide a liquid pump of the type mentioned that itt wear, reliable and also simple in construction This object is achieved according to the invention in that the piston is formed from a single piece of plastic with a recess at its free end so that the piston outer wall forms a sleeve whose wall thickness is dimensioned so that it seals against the cylinder inner surface when the piston moves forward applies and presses the writing fluid out of the cylinder chamber to the pen and that the piston diameter is selected so that when the piston moves backward between the end face of the sleeve and the cylinder surface there is a gap which prevents the inflow of writing fluid ^; n the cylinder space allowed The pump according to the invention is simple in structure, since it consists of relatively few individual parts and is wear-resistant Further features within the scope of the invention are characterized in the subclaims An exemplary embodiment is shown below with reference to the drawing of the invention described. The drawing shows a liquid pump 1 which supplies the writing liquid from the liquid container 2 a pen 3 conveyed. The liquid pump 1 consists of a pump housing 4 with a cylinder 5 and a plastic piston 6. For moving the piston 6 back and forth in the cylinder 5 are motor-driven means available that r-wr. r * -f "J _. I- ... 'te,. · .-. rln: _! ._: * C: z ~ j: _ CSlC L ^ IIIJlUUIIg LJClIIIIL CIIIC> JTIU3: 5IgIVdMI / UIII | JV. IUI XJl *. Conveying writing fluid from a fluid container to a scribe, with a pump housing with a cylinder and a piston, as well Means for moving the piston back and forth in the cylinder. A liquid pump of this type is known from the "Mingograph" recorder from Siemens AG. The piston made of metal is spring-loaded and is moved by an eccentrically mounted wheel. There are also several spring-loaded valves. The disadvantages of the known liquid pump best i_r ~ i Λ ~ άι ~ ι