Abstract: Easily removable instrument pen tip comprised of a body formed of resilient plastic with an ink passageway adapted to receive and sealingly engage an ink supply tube associated with a pen arm, the other end of which is adapted to receive and sealingly engage an elongated nib element, such as a stylus or fibrous nib. The pen tip body is a flat shaped member in which the passageway lies. The body may converge toward the ink passageway to serve as a visually indicating pointer. The body may also include locators or positioning ribs and reinforcing ribs. Preferably, the body and passageway include bent sections and the nib element and passageway are adapted for engagement only in the bent section passageway.

Abstract: Recording instrument marker mounting assembly is provided so that the marker can be pivoted relative to a mounting leg of the assembly which mounting leg is to be connected to an operating shaft of the recording instrument. In this manner, the lateral position of the marker can be adjusted relative to the recorder paper or chart which is to be imprinted upon. The mounting assembly comprises a mounting leg to be connected with the operating shaft, a cam connecting a marker support arm and the mounting leg, and cam follower means positioned on the support arm. Pivotal movement of the support arm relative to the mounting leg is actuated by rotation of the cam. In a preferred embodiment of the invention, the cam is formed integrally with a manually engageable precision adjustment knob, which includes a notch or the like so that the operator may gauge the position of the marker relative to the mounting leg.

Abstract: Improved upper and lower paired pen markers adapted to pass over one another with minimum spacing utilize interchangeable pen cartridges which are generally flat and rectilinear with the nib of the upper cartridge being slightly longer than that of the lower cartridge. The upper cartridge is supported from above in a holder with a front overhang lip, a sidewall positioning holding member and rear spring clips. As the bottom cartridge holder supports the bottom surface of the cartridge it also includes a sidewall positioning holding member and rear spring clips. Mispositioning of cartridge and holder is minimized despite the generally flat cartridge configuration.