U.S. patent number 3,921,780 [Application Number 05/489,599] was granted by the patent office on 1975-11-25 for assembly for mounting a print head.
This patent grant is currently assigned to General Electric Company. Invention is credited to Richard V. Gentzlinger, Werner H. Mailer.
United States Patent |
3,921,780 |
Gentzlinger , et
al. |
November 25, 1975 |
Assembly for mounting a print head
Abstract
An assembly for mounting a print head to a carriage. The
assembly includes a mounting clamp and a lock element in addition
to the print head and the carriage. The print head has at least two
mounting studs and a drive element engaging screw. Both the
carriage and the mounting clamp have openings therein through which
the studs and the lock element engaging screw pass when effecting
the assembly. The mounting clamp also has finger engaging tab
members and a ratchet element which includes a resilient free end
portion. In addition the stud receiving openings in the mounting
clamp includes a ramp structure. In assembly, the mounting clamp is
rotated by applying a torque to the tab members until the mounting
studs engage the ramp structure of their respective stud receiving
openings. Thereafter, the lock element engages the screw of the
spring head and is tightened thereon. Both the resilient free end
portion and the lock element are provided with ratchet teeth which
are in engagement during the tightening operation. As a result, an
audible clicking sound is generated which assures the operator that
a tightening operation is taking place. In this position reverse
rotation of the lock element relative to the free end portion is
prevented.
Inventors: |
Gentzlinger; Richard V.
(Waynesboro, VA), Mailer; Werner H. (Waynesboro, VA) |
Assignee: |
General Electric Company
(Waynesboro, VA)
|
Family
ID: |
23944501 |
Appl.
No.: |
05/489,599 |
Filed: |
July 18, 1974 |
Current U.S.
Class: |
400/175; 248/500;
285/912; 403/259; 400/124.11; 74/531; 285/362; 400/55 |
Current CPC
Class: |
B41J
25/34 (20130101); Y10T 74/2066 (20150115); Y10S
285/912 (20130101); F16B 2200/403 (20180801) |
Current International
Class: |
B41J
25/00 (20060101); B41J 25/34 (20060101); B41J
003/05 () |
Field of
Search: |
;197/1R,180,186R,36
;24/3R,243R ;74/531 ;248/500 ;403/259,261,316,353
;285/DIG.13,362,360,376,401,361 ;101/35,41 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Burr; Edgar S.
Assistant Examiner: Rader; R. T.
Claims
What is claimed is:
1. In combination, an assembly comprising:
a. a print head including an outer mounting member having at least
two mounting studs and screw means connected thereto and extending
outwardly therefrom;
b. a carriage including openings formed therein for the passage
therethrough of said mounting studs and said screw means;
c. a mounting clamp including slots formed therein for the passage
therethrough of said mounting studs and said screw means after
passage through said carriage openings, with the slots through
which said mounting studs pass including ramp means at one end
thereof, ratchet means having a resilient free end portion and
motion applying means for moving said mounting clamp between a
release position and a lock position; and
d. a lock element which engages said screw means and the resilient
free end portion of said ratchet means, and prevents the movement
of said mounting clamp from said lock position to said release
position.
2. The assembly as defined in claim 1, wherein said mounting clamp
comprises a plate-like member having a generally planar surface
with a central aperture surrounded by a rim portion, wherein the
slots are formed in said rim portion with the slots through which
the mounting studs pass being key-shaped and arcuate in their
longitudinal extent having a circular receiving end and an
elongated portion extending from the receiving end, and wherein
said ramp means are formed by the parallel edges of said elongated
portions with said edges having an inclination relative to the
planar surface of said mounting clamp.
3. The assembly as defined in claim 2, wherein said mounting studs
each include a screw member and an outer casing having an
internally threaded bore, an annular groove and a head portion, and
wherein the parallel edges of said ramp means associated with each
of said mounting studs are received within said annular groove for
engagement with said head portion.
4. The assembly as defined in claim 2, wherein said motion applying
means comprises a pair of tab members which extend axially
outwardly from the planar surface of said mounting clamp and
transversely across said rim portion.
5. The assembly as defined in claim 4, wherein said ratchet means
is mounted to said mounting clamp such that its free end extends
generally parallel to the planar surface of said mounting clamp,
wherein said free end is provided with an arcuate shape having
teeth formed on its convex surface, and wherein said lock element
comprises a cylindrical member having a threaded internal bore and
teeth formed on its outer surface, which engage the teeth formed on
the convex surface of said free end to effect locking of the
assembly.
6. The assembly as defined in claim 5, wherein said ratchet means
is mounted to one of said tab members.
7. The assembly as defined in claim 5, wherein the teeth formed on
the convex surface of said free end and the teeth formed on the
outer surface of said cylindrical member are mutually shaped so
that relative rotation of said lock element with respect to said
free end when said teeth are engaged occurs in only one
direction.
8. The assembly as defined in claim 7, wherein said free end
comprises a resilient material such that rotation of said lock
element relative to said free end when said teeth are engaged
generates an audible indication of the rotation.
9. A mounting clamp for securing one member to a second member
wherein said one member has a plurality of mounting studs connected
thereto, comprising a plate-like member having a generally planar
surface with a central aperture surrounded by a rim portion, said
rim portion having a plurality of slots formed therein and finger
engaging tab members extending axially outwardly therefrom, said
slots being key-shaped and arcuate in their longitudinal extent and
each having a circular end for receiving the mounting studs with
said second member nested between said one member and said
plate-like member, said slots having an elongated portion extending
from the receiving end with the parallel edges of said elongated
portion having an inclination relative to the planar surface, said
inclined parallel edges engaging the mounting studs in a
progressively tighter assembly during movement of the mounting
clamp relative to the two members, ratchet means for locking the
engagement of said inclined parallel edges with said mounting
studs, and means for unlocking said last named engagement.
10. A mounting clamp and lock arrangement for securing one member
to a second member wherein said one member has at least two
mounting studs and screw means connected thereto, comprising:
a. a mounting clamp in the form of a plate-like member having a
generally planar surface with a central aperture surrounded by a
rim portion, said rim portion having a slot formed therein for
receiving each of the mounting studs and the screw means with said
second member being nested between said one member and said
plate-like member, finger engaging tab members extending axially
outwardly therefrom for effecting movement of said mounting clamp
and ratchet means having a resilient free end portion, said slots
being arcuate in their longitudinal extent with the mounting stud
receiving slots being key-shaped and each having a circular end and
an elongated portion extending therefrom, and with the parallel
edges of said elongated portion having an inclination relative to
the planar surface, said inclined parallel edges engaging the
mounting studs in a progressively tighter assembly during movement
of the mounting clamp relative to the two members between a release
position and a lock position; and
b. a lock element which engages the screw means and the resilient
free end portion of said ratchet means, and prevents the movement
of said mounting clamp from said lock position to said release
position.
11. The arrangement as defined in claim 10, wherein said ratchet
means is mounted to said mounting clamp such that its free end
extends generally parallel to the planar surface of said mounting
clamp, wherein said free end is provided with an arcuate shape
having teeth formed on its convex surface, and wherein said lock
element comprises a cylindrical member having a threaded internal
bore and teeth formed on its outer surface, which engage the teeth
formed on the convex surface of said free end to effect locking of
the two members with the mounting clamp.
12. The arrangement as defined in claim 11, wherein said ratchet
means is mounted to one of said tab members.
13. The arrangement as defined in claim 11, wherein the teeth
formed on the convex surface of said free end and the teeth formed
on the outer surface of said cylindrical member are mutually shaped
so that relative rotation of said lock element with respect to said
free end when said teeth are engaged occurs in only one
direction.
14. The arrangement as defined in claim 13, wherein said free end
comprises a resilient material such that rotation of said lock
element relative to said free end when said teeth are engaged
generates an audible indication of the rotation.
15. In combination, a print head having a planar surface, a
carriage for moving said head and having a planar surface, said
carriage having a plurality of holes passing through its planar
surface, a mounting clamp for securing said print head and carriage
together at their planar surfaces, said print head having a
plurality of mounting studs extending from its planar surface for
passing through corresponding ones of said holes in said second
member, each of said studs having an undercut portion near its free
end to define a head with a shoulder, said clamp comprising a
plurality of elongated apertures, each of said apertures comprising
an enlarged opening at one end to receive the head of a respective
one of said studs after passage through a respective hole in said
carriage, each of said elongated apertures having associated
therewith a ramp section offset from the aperture in the direction
of the stud passage through the aperture and oriented substantially
in the direction of the aperture elongation such that upon turning
of the clamp the shoulder of each stud is caused to ride up the
ramp to force the print head and carriage together, said carriage
comprising ratchet teeth, said clamp having a peripheral tab
portion carrying ratchet teeth for meshing with corresponding
ratchet teeth of said carriage, said teeth being dimensioned to
permit meshing of ratchet teeth only in the direction of clamp
turning which forces the print head and carriage together, said tab
and said ratchet teeth portion of said carriage being resilient
relative to one another to enable manual disengagement of ratchet
teeth to permit loosening of the clamp.
16. A mounting clamp for securing first and second members together
at their planar surfaces wherein said second member comprises
ratchet teeth and a plurality of holes passing through its planar
surface and said first member has a plurality of mounting studs
extending from its planar surface for passing through corresponding
ones of said holes in said second member, and each of said studs
has an undercut portion near its free end to define a head with a
shoulder, said clamp comprising a plurality of elongated apertures,
each of said apertures comprising an enlarged opening at one end to
receive the head of a respective one of said studs after passage
through a respective hole in said second member, each of said
elongated apertures having associated therewith a ramp section
offset from the aperture in the direction of the stud passage
through the apertures and oriented substantially in the direction
of the aperture elongation such that upon turning of the clamp the
shoulder of each stud is caused to ride up the ramp to force the
first and second member together, said clamp having a peripheral
tab portion carrying ratchet teeth for meshing with corresponding
ratchet teeth of said second member, said teeth being dimensioned
to permit meshing of ratchet teeth only in the direction of clamp
turning which forces the print head and carriage together, said tab
being resilient to enable manual disengagement of ratchet teeth to
permit loosening of the clamp.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to an assembly in which a
print head, in this case a matrix wire print head, is secured to a
carriage. More specifically, the present invention relates to an
assembly including a clamp having means to prevent the print head
from becoming disengaged from the carriage while also readily
facilitating removal of the print head from the carriage.
Many types of office machines are provided with print heads in
order to produce an observable output. These print heads have a
high degree of replacement in comparison to many of the other
components of the machine. Quite frequently, special tools are
needed in order to mount and replace the print head. All of this is
time consuming and consequently expensive.
It would therefore be desirable to have a structure which provides
a simplified means of positively affixing a print head and in
particular a matrix wire print head to a carriage without the need
of special tools.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore, a general object of the present invention to
provide an assembly for mounting a print head, and in particular a
matrix wire print head, to a carriage so that the print head can be
mounted and removed from the carriage in a simplified manner.
It is a more specific object of the present invention to provide an
assembly having a mounting clamp for mounting a print head, and in
particular a matrix wire print head, to a carriage so that the
print head can be mounted and removed from the carriage in a
simplified manner and so that loosening of the print head from the
carriage is prevented.
It is another object of the present invention to provide an
assembly having a mounting clamp for positively affixing a print
head, and in particular a matrix wire print head, to a carriage
without the need of special tools.
It is a further object of the present invention to provide means
for audibly detecting when the print head and the carriage are
sufficiently engaged to assure a tight connection.
These and other objects are accomplished according to the present
invention by the provision of a mounting clamp and a lock element
in assembly with the print head and carriage. The mounting clamp
includes means for drawing the print head and carriage into a tight
assembly, while the lock element includes a pair of ratchet teeth
configured so that relative movement in only one is permitted
without the application of an external force to separate the pair
of ratchet teeth.
According to one embodiment, the print head is itself adapted to be
mounted in accordance with the present invention by the provision
thereon of at least two mounting studs and a screw element. To
accommodate the mounting studs and screw element, the carriage and
mounting clamp are provided with appropriate openings, with the
stud openings in the mounting clamp having a ramp structure
associated therewith for cooperation with the mounting studs. The
mounting clamp is also provided with a ratchet detent element
formed preferably integrally with the mounting clamp and including
a resilient free end portion. When assembled, the lock element
engages both the print head screw and the ratchet detent element
after the mounting clamp has been rotated to bring the mounting
studs into wedging engagement with their associated ramp structure,
and is tightened onto the screw element thereby intensifying the
wedging action which results in the final mounting of the print
head to the carriage.
The lock element according to this embodiment has internal screw
threads and external ratchet teeth. The threads engage the threads
of the print head screw, while the ratchet teeth engage the ratchet
detent element. As the lock element is advanced axially relative to
the screw, it also causes the ratchet detent element to be
deflected and this latter movement produces an audible clicking
sound that ceases once the drive element has been tightened enough
to remove any clearance between the print head, the carriage and
the mounting clamp.
The matters discussed above, as well as further objects and
features of the present invention, will be more clearly understood
and appreciated following a consideration of the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded elevational view of an assembly including a
print head, carriage, and print head mounting clamp in accordance
with the present invention;
FIG. 2 is an elevational end view of the mounting clamp according
to one exemplary embodiment of the present invention in initial
engagement with the studs of the print head;
FIG. 3 is an elevational end view of the mounting clamp according
to the same exemplary embodiment of the present invention shown in
FIG. 2 after final engagement of the clamp with the studs of the
print head;
FIG. 4 is a sectional view taken along the line 4--4 of FIG. 2
illustrating the relationship of the mounting studs to a portion of
the mounting clamp during the initial engagement of the mounting
clamp and the print head;
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 3
illustrating the relationship of the mounting studs to a portion of
the mounting clamp during the final engagement of the mounting
clamp and the print head;
FIG. 6 is a further detail view of the ratchet teeth
arrangement;
FIG. 7 is an elevational end view of the mounting clamp according
to another exemplary embodiment of the present invention after
final engagement of the clamp with the studs of the print head;
FIG. 8 is an elevational side view of the mounting clamp according
to the same exemplary embodiment of the present invention shown in
FIG. 7;
FIG. 9 is a cross-sectional view taken along the line 9--9 of FIG.
8; and
FIG. 10 is a partial view in perspective of still another exemplary
embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a print head 10, which is one
embodiment comprises a wire matrix print head, a supporting portion
12 of a movable carriage which is not further shown, a mounting
clamp 14 and a ratcheted knob or locking element 16. For
convenience, the mounting or supporting portion 12 forms part of a
carriage which is used to support the print head and move it across
a record medium and will hereinafter be referred to simply as the
carriage 12. These elements represent the essential elements of the
assembly which embodies the structural aspect of the present
invention. Further details of a print head operation are shown in
the co-pending application Ser. No. 423,779, assigned to a common
assignee, dated Dec. 11, 1973.
The print head 10 is relatively complex from the standpoint of its
total structural configuration. Printing takes place by moving
print wires of guide member 22 longitudinally and transversely of
carriage motion to impact the record medium at the remote or right
hand end of member 22. Since the present invention is not, however,
concerned with the print head per se but rather with the mounting
of the print head, the illustration of the print head has been
generalized with particulars as to its external structural
configuration which are essential to the understanding of the
present invention being shown in the most detail. With this in
mind, it can be seen that the print head 10 includes a support
member 18, shown as being of generally cylindrical configuration,
which defines a transverse surface 20. From the surface 20 there
extends the guide member 22 for print wires which also serves as a
carriage engaging guide which is generally convergently tapered in
an outward direction from the surface 20. The guide member 22 is
shown centrally located with respect to the surface 20 although
this is not a requirement. Also extending from the surface 20 are
preferably two diametrically disposed mounting studs 24 and a screw
26. The mounting studs 24 are shown as internally threaded to
support member 18 and are in threaded engagement with screws (not
shown). The studs 24 are provided with annular grooves 28 and
terminal heads 30. The heads 30 have tool engaging grooves 32
extending transversely across them.
The carriage 12 comprises a generally flat surface within which a
U-shaped opening 34 is formed to admit guide member 22 so that the
guide member 22 extends therethrough. The carriage 12 has also
further openings 36 through which the studs 24 extend and an
opening 38 through which the screw 26 extends.
To clamp the print head 10 to the carriage 12 there is provided the
mounting clamp 14. For example, a thermoplastic material sold under
the Trademark "Lexan" may be used for the mounting clamp 14.
The mounting clamp 14 is preferably molded as a one-piece circular
plate having, as shown in FIG. 2, a central opening 40 through
which the guide member 22 extends. The opening 40 is surrounded by
a rim portion 42 within which slots 44 and 46 are formed. In
addition, the rim portion 42, as shown in FIG. 2, has axially
extending finger engaging tab members 48, as shown in FIG. 1,
formed integrally therewith. These tab members 48 are provided to
facilitate rotation of the mounting clamp 14, shown in FIG. 1. From
one of these tab members there extends a ratchet detent member 50.
The ratchet detent member 50, preferably formed integrally with its
respective tab member, has a generally arcuately shaped resilient
free end, see FIG. 2, which has ratchet teeth 52 along its top
convex surface. The ratchet detent teeth 52 mesh with ratchet teeth
54 formed on the outer surface of the knurled knob 16, see FIGS. 1
and 3. The preferred configuration of the ratchet teeth 52 and 54
is shown in FIG. 6. There are two slots 44, one for each of the
studs 24. The other slot 46 is provided, see FIGS. 1 and 2, to
accommodate the screw 26. The slots 44 and 46 are also generally
arcuate in shape. In this way, the mounting clamp 14, FIG. 1, can
be rotated between a release position (FIG. 2) and a lock position
(FIG. 3). The slots 44 are furthermore key-shaped having a
receiving opening 44a, from which an elongated opening 44b extends.
On either side of the openings 44b and coextensive therewith, there
are formed in the rim portion 42, ramp edges 56. The ramp edges 56
are shown most clearly in FIGS. 4 and 5.
Having now identified the relevant structural aspects of the
present invention, attention is now directed to the
interrelationship of the various elements and their cooperation in
assembly to effect simple and rapid mounting and removal of the
print head 14. In this regard, reference will be made to FIGS.
2-6.
In FIGS. 2 and 4 the assembly is shown with the mounting clamp 14
in its initial unrotated release position. In this position the
mounting studs 24 are received within the openings 36 of the
carriage 12 and the receiving openings 44a of the slots 44 of the
mounting clamp 14, and the screw 26 is received within the opening
38 of the carriage 12 and the slot 46 of the mounting clamp 14. The
next stage in the assembly is to rotate the mounting clamp 14 in a
clockwise direction (shown clockwise by arrow B) by applying a
torque to the axially extending finger engaging tab member 48.
During this motion, the relationship between the studs 24, the
screw 26 and the mounting clamp 14 changes to that shown in FIGS. 3
and 5. In particular the ramp edges 56 enter their associated
annular grooves 28 in the studs and engage shoulders 58 defined by
the terminal heads 30. The shoulders 58 move up the ramp edges 56
during the rotation until the lock position shown in FIG. 3 is
reached. This engagement securely wedges the carriage 12 between
the print head 10 and the mounting clamp 14.
In this position the knurled knob 16 is threaded onto the screw 26.
As the knob 16 is axially advanced along the screw 16, the ratchet
teeth 54 engage the ratchet teeth 52 as shown in FIG. 6. These
teeth are so designed so that rotation in the direction of
tightening (clockwise as shown) of the knob 16, (direction A of
FIG. 6) is permitted while rotation in the other or loosening
direction (counterclockwise) is prevented. During the tightening
rotation, the teeth engagement causes the resilient free end of the
ratchet member 50 to undergo alternating deflection. This in turn
generates an audible clicking sound which assures the operator that
the knob 16 is being tightened in a direction to remove any
clearances between the carriage 12, the print head 10 and the
mounting clamp 14, thereby assuring a tight connection. The
assembly is now securely locked because counterclockwise rotation
in the loosening or counterclockwise direction is prevented by the
engagement of the teeth 52 and 54.
In order to remove the print head 10 from the carriage 12, it is
first necessary to deflect the resilient free end of the ratchet
detent member 50 in the direction of the arrow C to a sufficient
degree to allow counterclockwise rotation of the knob 16. Continued
counterclockwise rotation of the knob 16 causes it to be removed
from the screw 26. When this is done, then the mounting clamp 14
can be rotated counterclockwise by applying an appropriate torque
to the finger engaging tab members 48. In the release position
shown in FIGS. 2 and 4, the print head 10 can be axially displaced
and removed from the carriage 12.
Turning now to FIGS. 7-9, another embodiment of the present
invention is shown according to which the ratchet detent member 50
is replaced with a ratchet detent member 60 supported by a tab 61
extending from the mounting clamp 14. Instead of a screw 26 and a
knob 16, there is provided according to this embodiment a set of
ratchet teeth 62 extending from the edge of the carriage 12. The
relative configuration of the ratchet teeth 62 and those formed on
the ratchet member 60 is similar to that of the previously
described embodiment. As can be seen from FIG. 8, the ratchet
member 60 is offset from the plane of the rim portion 42. The
rotation of the mounting clamp 14 to tighten the ramp edges 56
against the stud shoulders 58 also produces rotation of the ratchet
member 60 relative to the mounting clamp 14 and consequently the
ratchet teeth 62. This brings about engagement of the teeth 62 and
those of the ratchet member 60 and locks the mounting clamp 14 in
place. By lifting the ratchet member 60 out of engagement with the
teeth 62, the mounting clamp 14 can be rotated in a direction to
disengage the ramp from the shoulders 58 and hence the mounting
clamp 14 from the print head.
Further according to this embodiment, the mounting clamp 14 is
loosely captured or held to the carriage 12 by means of clips 63,
which may be L-shaped projections as shown in FIG. 9, supported by
and extending from the surface of the carriage 12.
In a still further embodiment according to the present invention
and shown in FIG. 10, a tab 64 is provided with ratchet teeth on
its back surface which engage ratchet teeth carried on the front
surface of the carriage 12. The tab 64 and the ratchet toothed
portion of the carriage 12 are designed to be separated when the
mounting clamp is to be unclamped. This is accomplished by making
one to be resilient with respect to the other as by making the tab
64 of resilient thermoplastic.
As can be seen from the above description, the existing state of
the art has been advanced and there is now available a unique
mounting clamp and cooperating elements which makes it possible to
mount and remove a print head, and in particular a matrix wire
print head, in a simple and effective manner. In addition, the
mounting and removal is effected without the need of special tools
and in such a manner that loosening of the mounted print head is
prevented.
* * * * *