Improvements in syringes / [Martin Overlach].

  • Overlach, Martin.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Improvements in syringes / [Martin Overlach]. Source: Wellcome Collection.

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    5 10 15 20 25 30 35 40 45 N° 2241 A. D. 1880 Date of Application, 7th Feb., 1889 Complete Specification Left, 26th Oct., 1889—Accepted, 30th Nov., 1889 PROVISIONAL SPECIFICATION. Improvements in Syringes. I, Dr. Maktin Overlach, of Frankfort-on-the-Main in the Empire of Germany Physician do hereby declare the nature of this invention to be as follows :— This invention relates to injection and other syringes and comprises improved means tor making a tight, joint on the one hand between the syringe cylinder and the injection nozzle at the front end of the same, and on the other hand between the said cylinder and the part by which the rear end of the latter is closed and which forms a guide for the piston-rod. Owing to the great difficulty in the wholesale manufacture of syringes, of making the glass cylinders of exactly equal diameters and lengths and forming straight edges at right angles to the sides of the same, the means heretofore used for forming the joints between the cylinder fittings and the body of the syringe have the following serious defects. The putty or cement for securing the fittings or ends to the glass cylinder will last only a short time by reason of its contact with the liquids used, and will moreover prevent the syringe from being completely dismounted for cleaning purposes. The cutting of a screw thread upon the ends of the glass cylinder renders the latter very liable to break and the substitution of a broken cylinder by another becomes very difficult or impossible if there is the slightest inequality in the glass cylinder. The joint at the nozzle end which is mostly made by means of an impregnated leather washer or disc usually commences to leak very quickly. The body of the syringe cannot be hermetically closed by clamping the same between two end caps or plates connected by metal rods and caused to approach each other by means of nuts unless the edges or end surfaces of the glass cylinder are quite straight and at right angles to the sides of the same. This requires accurate work which is not usually carried on in the wholesale manufacture of syringes. The syringe constructed according to my invention is designed to obviate the aforesaid defects which are extremely serious considering the importance of a reliable and absolutely clean instrument. By its improved arrangement it enables putty or other binding material to be dis¬ pensed with and the end surfaces of the cylinder do not require to be formed straight and at right angles to the sides of the cylinder. It permits the use of glass tubes having absolutely flat walls and no threads and obviates the necessity for accurate equality in the inside width of the cylinder and in the thickness of the wall of the latter. Furthermore it enables all the parts to be kept thoroughly clean because they are all exposed to view, and advantageously differs from the syringes hitherto employed by its great simplicity. A socket arranged at the rear end of the syringe cylinder serves as a guide for the piston rod. This socket has at its end extending into the said cylinder a disc and is provided with a screw thread over which a packing ring and a disc are slid, and with which engages a cap provided with a female thread. By screwing this can more or less tightly against the aforesaid disc the packing ring between the latter and the disc formed on the socket is more or less powerfully compressed. In consequence of this compression the circumference of the packing ring becomes larger and is pressed more or less firmly against the inner wall of the cylinder, thereby pro¬ ducing a more reliable and tight joint between the guide tor the piston rod and the body of the syringe. In order to further increase the tightness of this joint the inner wall of the glass cylinder, where it comes in contact with the packing ring is provided with a groove into which the circumference of the packing ring [.Price