Writing or drafting instrument with exchangeable writing medium container

A writing or drafting instrument includes a writing medium container in the form of an exchangeable cartridge and a push member which is axially movable in the shaft of the instrument and is used as an ejector. The cartridge is held in the shaft by a clamping action or a positive locking action. The push member and shaft form a structural group in which the push member and the shaft are movable relative to each other. The push member acts on the cartridge at least during the ejection of the cartridge. The writing tip is exchangeably fastened in the cartridge or in the shaft.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a writing or drafting instrument with a 
writing medium container in the form of an exchangeable cartridge and with 
a push member which is axially movable in the shaft of the instrument and 
is used as an ejector, wherein the cartridge is held in the shaft by a 
clamping action or a positive locking action. 
2. Description of the Related Art 
Writing or drafting instruments of the above-described type are known in 
principle. For example, utility models 1 963 329 and 1 920 667, German 
Patent 30 42 035 and U.S. Pat. No. 3,361,516 illustrate and describe felt 
tip pens in which a replaceable cartridge held in a shaft by clamping 
action or positive locking action is utilized as an exchangeable writing 
medium container. The cartridges have at their rearward ends closing 
members which can be used as push members or ejectors and which are 
constructed in such a way that, after the cartridge has been inserted into 
the shaft, the cartridge axially protrudes beyond the shaft or closes the 
open end of the shaft. In the forward end of each cartridge is fixedly 
arranged a fiber wick as writing element. 
When the respective cartridge is replaced, the entire cartridge is 
replaced. This means that it is always necessary to exchange or discard 
and replace the push member or ejector as well as the writing element 
together with the empty cartridge, even though these components are 
usually still in operating condition and could be reused. In the 
instruments according to German Utility Model 1 920 667 and U.S. Pat. No. 
3,361,516, the manipulation during the exchange of the cartridge 
additionally poses a significant problem because a separate tool is 
required for ejecting the cartridge from the shaft, wherein the separate 
tool may be the protective cap. 
In addition, German Laid-Open Application 22 08 111 discloses disposable 
writing utensils which have a spare writing medium reservoir which, when 
the main writing medium reservoir has become empty, can be connected to 
the main reservoir by axially actuating a push member so that the writing 
medium contained in the spare reservoir can flow into the main reservoir, 
in order to indicate to the user that the entire writing instrument is now 
being used in "spare operation" and must be replaced soon. 
Accordingly, after the writing medium contained in the spare reservoir has 
been used up, the entire writing instrument must be disposed of. 
SUMMARY OF THE INVENTION 
Therefore, it is the primary object of the present invention to provide a 
reusable writing or drafting instrument whose writing medium container is 
constructed as an exchangeable cartridge which can be exchanged easily and 
quickly, and in which the exchange of the cartridge does not produce 
unnecessary waste components. 
In accordance with the present invention, the above object is met by a 
writing or drafting instrument of the above-described type in which the 
push member and shaft form a structural group in which the push member and 
the shaft are movable relative to each other. The push member acts on the 
cartridge at least during the ejection of the cartridge. The writing tip 
is exchangeably fastened in the cartridge or in the shaft. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of the disclosure. For a better understanding of the invention, its 
operating advantages, specific objects attained by its use, reference 
should be had to the drawing and descriptive matter in which there are 
illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 of the drawing shows a writing instrument according to the present 
invention in which the writing medium container in the form of a cartridge 
3 is inserted into a shaft 1 and held in the shaft by a clamping action. 
The cartridge 3 is shown pierced and, as a result, ready for operation. 
The shaft 1 is constructed as a single piece and is partially provided 
with gripping undulations 15. 
A push member 2 is arranged in the rearward portion of the shaft 1. A push 
member cap 20 of the push member 2 protrudes axially beyond the shaft 1. 
The push member cap 20 is provided with tongue-type webs 21. Stop cams 22 
are provided on the webs 21. The stop cams 22 project into openings 12 of 
the shaft wall 11 and are axially movable between two stops 18 and 19. 
The filling space 30 of cartridge 3 contains ink as writing medium and is 
permanently closed at one side by a closing plug 38 and is closed at the 
front end by a releasable closing member 39, so that the cartridge can be 
emptied. In the position shown in FIG. 1, the closing member 39 has 
already been opened. 
A writing tip 4 can be screwed into a compensating zone 31 of the cartridge 
3. As shown in FIG. 1, a connecting pin 44 has forced the closing member 
39 into the filling space 30 when the cartridge 3 was pierced, so that the 
writing medium can flow into the interior of the writing tip 4 and, if 
necessary, also into the compensating system 41. The cartridge 3 has a 
collar 37 which then securely rests against the stop edge 17 of the shaft 
1. 
The writing tip 4 is screwed into the cartridge 3 by means of a fastening 
thread 43. A writing tube 42 of the writing tip 4 is closed in an airtight 
manner in a storage position from the front by a sealing member 51 of a 
closing cap 5 which is tightly screwed onto a shaft thread 14 of the 
housing or shaft. 
When the push member 2 is axially actuated by the push member cap 20 after 
the closing cap 5 has been removed, the end face 23 of the push member cap 
20 presses against the closing plug 38 and pushes the entire cartridge 3 
out of the shaft 1. The axial length of the effective clamping zone 34 
existing between the shaft 1 and the cartridge 3 is advantageously longer 
than the axial actuating path 26 of the push member 2, so that the 
cartridge 3 does not unintentionally drop out after full actuation of the 
push member 2, but can merely be grasped well by the fingers of the user 
and, if necessary, can be easily forwardly pulled out of the shaft 1. When 
a new cartridge 3 is inserted, the cartridge 3 is pushed from the front 
into the shaft 1 until the collar 37 securely rests against the stop edge 
17 of the shaft 1 at the end face thereof. In the condition in which the 
writing instrument is sold, the writing tip 4 is not yet completely 
inserted into the compensation zone 31 of the cartridge 3, so that the 
closing member 39 still closes the filling space 30 and, thus, the writing 
or drafting instrument can be stored for a long period of time. 
FIG. 2 of the drawing shows the cartridge 3 of FIG. 1 as a complete 
structural unit in the condition in which the writing instrument is sold, 
wherein the writing tip 4 has not yet been completely screwed in and 
wherein the closing member 39 is rigidly and tightly placed in the closure 
opening and has not yet been pressed into the filling space 30 by the 
connecting pin 44. The writing tip 4, which is arranged in a preassembled 
manner in the compensation zone 31, is provided with a compensating system 
41, assembly surfaces 46, a writing tube 42, a releasable securing ring 45 
and a removable protective cap 6 and is screwed with a fastening thread 43 
into the cartridge thread 33 to such an extent that the securing ring 45 
rests against the end face of the collar 37 with a slight pretension. In 
order to place the writing instrument in operating position or in the 
position of use, the protective cap 6 is removed, the cartridge 3 is 
inserted into the shaft 1, not shown in FIG. 2, and is secured through the 
clamping zone 34, and the writing tip 4 is screwed into the cartridge 3 to 
such an extent that the securing ring 45 is completely severed from the 
writing tip 4, on the one hand, and, on the other hand, the closing member 
39 is removed from the closure opening or is pressed into the filling 
space 30 at least to such an extent that the writing medium can flow into 
the interior of the writing tip 4. The writing instrument is ready for use 
as soon as all interior spaces of the writing tip 4 have been filled with 
writing medium up to the tip of the writing tube 42. 
As illustrated in FIGS. 3 and 4, the cartridge 3 has on its outer surface 
securing webs 35 provided with web points 36 and clamping webs 32 in the 
clamping zone 34 or between the securing webs 35. The securing webs 35 
interact with shaft webs 13 shown in FIG. 5 and, consequently, effect 
locking against rotation between the shaft 1 and the cartridge 3 in order 
to make possible or facilitate screwing of the writing tip 4 into or out 
of the cartridge 3 when the writing tip is to be screwed into the 
cartridge thread 33. 
If plug-in connections are provided exclusively, locking against rotation 
is unnecessary. The collar 37 limits the depth of insertion of the 
cartridge 3 relative to the shaft 1, on the one hand, and, on the other 
hand, the depth by which the writing tip 4 can be screwed into the 
compensation zone 31 when the securing ring 45 has not yet been removed. 
The shaft 1 illustrated in FIGS. 5 and 6 has a shaft wall 11 with openings 
12, shaft webs 13, gripping undulations 15 and a shaft thread 14. The 
radially extending window-like openings 12 are provided with axially 
acting rear and front stops 18 and 19 for securing the push member 2, and 
the shaft webs 13 arranged in the interior and provided with centering 
wedges 16 effect together with the securing webs 35 of the cartridge 3 a 
locking against rotation between the shaft 1 and the inserted cartridge 3 
resting against the contact edge 17. 
FIGS. 7-9 of the drawing show the push member 2 in three different views. 
The stop cams 22 mounted on the radially resilient tongue-type webs 21 and 
provided with insertion inclinations 25 are arranged axially approximately 
in the center of the push member 2. The push member 2 acts with its end 
face 23 on the cartridge 3 which, when the cartridge is ejected, comes 
into contact with the cartridge. 
The tongue-type webs 21 are defined by recesses 24 which are formed as 
radial openings of the push member wall 27. The push member 2 can be 
mounted by a simple insertion into the shaft 1 which is open at the rear, 
wherein the tongue-type webs 21 are resilient radially inwardly for 
overcoming the diameter difference of the stop cams 22 until the stop cams 
22 engage in the openings 12 of the shaft 1. For carrying out the 
disassembly, the stop cams 22 are initially pushed inwardly radially until 
the push member 2 can be pushed toward the rear and can be removed. 
Writing instruments or drafting instruments having a writing medium 
container in the form of an exchangeable cartridge 3 and a push member 2 
which is to be used as an ejector and is axially movable in the shaft 7 
and in which the cartridge 3 is held in the shaft 1 by a clamping action 
or a positive locking action, should preferably be constructed in such a 
way that the push member 2 and the shaft 1 form a structural group in 
which the push member 2 and the shaft 1 are movable relative to each 
other, wherein the push member 2 acts on the cartridge 3 at least during 
the ejection thereof and the writing tip 4 is exchangeably mounted in the 
cartridge 3 or in the shaft 1. 
The cartridge 3 should have a filling space 30 and/or a compensation zone 
31. 
It is particularly advantageous if the cartridge 3 and the writing tip 4 
form a structural unit and if the writing tip 4 is exchangeably fastened 
in the cartridge 3. 
In accordance with a very advantageous solution, the cartridge 3 and the 
writing tip 4 are sold only in the preassembled state, wherein the writing 
tip 4 is not completely inserted into the cartridge 3 and the connecting 
pin 44 of the writing tip 4 opens the closing member 39 of the cartridge 3 
only after the writing tip 4 has been fully inserted into the cartridge 3 
and keeps the closing member 39 open in the state of operation. 
In accordance with another advantageous feature, the push member 2 is 
mounted in the shaft 1 so as to be axially movable between two stops 18 
and 19 and the shaft 1 has at least one opening 12 in which the push 
member 2 is held so as to be axially movable to a limited extent. For this 
purpose, the push member 2 may have tongue-type webs 21 and stop cams 22 
by means of which the push member 2 is held in the shaft 1 so as to be 
axially movable between two stops. 
For an easy assembly or a possibly automatic assembly, the tongue-type webs 
21 and/or the stop cams 22 should have insertion inclinations 25 extending 
toward the end face 23. 
If components are used which are threadedly engaged with each other, such 
as, threaded writing tips, it is very advantageous if the shaft 1 has at 
least one shaft web 13 and the cartridge 3 has at least one securing web 
35 for locking against rotation and if each shaft web 13 has a centering 
wedge 16 and each securing web 35 of the cartridge 3 has a web point 36 
for facilitating the insertion. 
The cartridge 3 may be provided in the area of the compensation zone 31 
with a cartridge thread 33 adapted to the fastening thread of the writing 
tip 4, so that the two components are fastened relative to each other in a 
way which makes exchange possible. 
For fastening the cartridge 3 in the shaft 1 it is advantageous if at least 
one clamping web 32 is arranged in the region of a clamping zone 34 on the 
cartridge 3 between the securing webs 35 or alternatively between two 
shaft webs 13 on the shaft 1. 
The shaft of the writing instrument or drafting instrument according to the 
present invention may also be constructed in two pieces in the known 
manner and the writing tip may be received directly in the front portion 
or the mouthpiece portion. In this case, the shaft is disassembled for 
exchanging the cartridge, the empty cartridge is separated from the shaft, 
possibly after the push member has been actuated, and the push member is 
removed, and the shaft is reassembled after a new cartridge has been 
inserted. 
The invention is not limited by the embodiments described above which are 
presented as examples only but can be modified in various ways within the 
scope of protection defined by the appended patent claims.