U.S. patent application number 11/021360 was filed with the patent office on 2006-03-23 for knuckle arm.
Invention is credited to Tai-Xiong Chen, Kuang-Wei Zhang.
Application Number | 20060060736 11/021360 |
Document ID | / |
Family ID | 35998810 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060060736 |
Kind Code |
A1 |
Zhang; Kuang-Wei ; et
al. |
March 23, 2006 |
KNUCKLE ARM
Abstract
A knuckle arm interconnects a machine body and a top cover of a
machine, and includes a base fixed on the machine body and having a
receiving frame, an inner sliding seat slidable within the
receiving frame and having a cam surface, a resilient member
disposed between the receiving frame and the inner sliding seat, a
first pivotable seat sleeved on the base, a pressing rod extending
through the first pivotable seat and biased to contact the cam
surface, and a second pivotable seat slidable on the first
pivotable seat and attached to the top cover of the machine.
Inventors: |
Zhang; Kuang-Wei; (Dong-Guan
City, CN) ; Chen; Tai-Xiong; (Dong-Guan City,
CN) |
Correspondence
Address: |
CHRISTIE, PARKER & HALE, LLP
PO BOX 7068
PASADENA
CA
91109-7068
US
|
Family ID: |
35998810 |
Appl. No.: |
11/021360 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
248/285.1 |
Current CPC
Class: |
G03B 27/62 20130101;
Y10T 16/54025 20150115 |
Class at
Publication: |
248/285.1 |
International
Class: |
E04G 3/00 20060101
E04G003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 22, 2004 |
TW |
093128708 |
Claims
1. A knuckle arm adapted to be connected to a machine body and a
top cover of a machine, said knuckle arm comprising: a base
including a mounting plate unit adapted to be disposed fixedly on
the machine body, two pivot plates connected fixedly to said
mounting plate unit, two first pivot holes formed respectively
through said pivot plates, and a receiving frame secured between
said pivot plates, said receiving frame including a top wall, a
bottom wall that is spaced apart from said top wall, and an
abutment wall interconnecting said top and bottom walls fixedly to
define an accommodating chamber among said top wall, said bottom
wall, said abutment wall and said pivot plates; an inner sliding
seat disposed movably within said accommodating chamber in said
base and having a cam surface; at least one resilient member
disposed within said accommodating chamber in said base and biasing
said inner sliding seat to move away from said abutment wall; a
first pivotable seat including two first wing plates located
respectively to two opposite sides of an assembly of said pivot
plates, a first connecting plate interconnecting said first wing
plates fixedly, two through holes formed respectively through said
first wing plates, and two apertures formed respectively through
said first wing plates; a pressing rod extending through said
through holes in said first pivotable seat and biased by said
resilient member to contact said cam surface of said inner sliding
seat; a second pivotable seat including two second wing plates
located respectively to two opposite sides of an assembly of said
first wing plates of said first pivotable seat, a second connecting
plate interconnecting said second wing plates fixedly and adapted
to be attached to the top cover of the machine, two limiting plates
connected respectively and fixedly to and perpendicular to the
second wing plates to define a limiting chamber among said second
wing plates, said second connecting plate and said limiting plates,
two second pivot holes formed respectively through said second wing
plates, and two curved slots formed respectively through said
second wing plates; a first pivot rod extending through said second
pivot holes in said second pivotable seat and said first pivot
holes in said base; and a second pivot rod extending through said
curved slots in said second pivotable seat and said apertures in
said first pivotable seat.
2. The knuckle arm as claimed in claim 1, wherein said first
pivotable seat further includes two engagement blocks extending
respectively and integrally from said first wing plates toward each
other and situated such that said second pivot rod presses against
said engagement blocks.
3. The knuckle arm as claimed in claim 2, wherein said top and
bottom walls of said base are inclined relative to said mounting
plate unit, said inner sliding seat being movable within said
accommodating chamber in said base in a direction inclined relative
to said mounting plate unit.
4. The knuckle arm as claimed in claim 3, further comprising a
third pivotable seat and a third pivot rod, said second pivotable
seat further including two third pivot holes formed respectively
through said second wing plates, said third pivotable seat
including two third wing plates located respectively to two
opposite sides of an assembly of said second wing plates of said
second pivotable seat, a coupling plate interconnecting said third
wing plates fixedly and adapted to be connected fixedly to the top
cover of the machine, two fourth pivot holes formed respectively
through said third wing plates, and two fifth pivot holes formed
respectively through said third wing plates, said first pivotable
seat further including two slots formed respectively through said
first wing plates, said third pivot rod extending through said
fourth pivot holes in said third pivotable seat, said third pivot
holes in said second pivotable seat, and said slots in said first
pivotable seat, said second pivot rod extending through said fifth
pivot holes in said third pivotable seat, said curved slots in said
second pivotable seat, and said apertures in said first pivotable
seat.
5. The knuckle arm as claimed in claim 4, wherein said resilient
member is configured as a coiled compression spring that has a
first end foot pressing against said abutment wall of said
receiving frame of said base, and a second end foot pressing
against said inner sliding seat.
6. The knuckle arm as claimed in claim 5, wherein said cam surface
of said inner sliding seat has opposite first and second ends, and
a convex middle portion disposed between said first and second
ends.
7. The knuckle arm as claimed in claim 6, wherein said inner
sliding seat further has an abutment surface opposite to said cam
surface, and four engagement walls extending from said abutment
surface toward said abutment wall of said receiving frame, said
engagement walls abutting respectively against said pivot plates,
and said top and bottom walls of said base.
8. The knuckle arm as claimed in claim 7, wherein said inner
sliding seat further has an annular flange that extends from said
abutment surface toward said abutment wall of said base, said
second end foot of said resilient member being sleeved on said
annular flange in a close fitting manner.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority of Taiwanese Application
No. 093128708, filed on Sep. 22, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a part of an office machine, and
more particularly to a knuckle arm that interconnects a machine
body and a top cover of an office machine.
[0004] 2. Description of the Related Art
[0005] Two knuckle arms are typically disposed between a top cover
and a machine body of an office machine, such as a copier, or
scanner, for use in the opening and closing of the top cover
relative to the machine body. Referring to FIG. 1, a conventional
knuckle arm 10, which is disclosed in U.S. Pat. No. 6,456,365, is
shown to include a mounting seat 11 fixed on a machine body 21 of
an office machine 20, a connecting seat 12 disposed pivotally on
the mounting seat 11, a bottom cam sliding seat 13 disposed
slidably within the connecting seat 12, a top cam sliding seat 14
disposed slidably within the connecting seat 12 and located above
the bottom cam sliding seat 13, a compression spring 15 disposed
between the bottom and top cam sliding seats 13, 14, a lifting seat
16 disposed pivotally on the connecting seat 12 and connected
fixedly to a top cover 22 of the office machine 20, a bottom pivot
rod 17 extending through the mounting seat 11 and the connecting
seat 12 and kept in contact with a cam surface 131 of the bottom
cam sliding seat 13, and a top pivot rod 18 extending through the
connecting seat 12 and kept in contact with a cam surface 141 of
the top cam sliding seat 14.
[0006] As such, a force can be applied to the top cover 22 so as to
open and close the top cover 22 relative to the machine body 21.
Although the knuckle arm 10 can achieve its intended purposes, in
actual use, it suffers from the following disadvantages: [0007] (1)
Since the total weight of the lifting seat 16, the connecting seat
12, the top cam sliding seat 14, the spring 15 and the bottom cam
sliding seat 13 is significant, the user must exert a large force
to open and close the top cover 22. This particularly burdensome
when the top cover is opened or closed with one hand. [0008] (2)
Lubrication oil is applied between the connecting seat 12 and each
of the top and bottom cam sliding seats 14, 13 so as to enable
smooth movement of the top and bottom cam sliding seats 14, 13
within the connecting seat 12. However, because the connecting seat
12 as well as the top and the bottom cam sliding seats 14, 13 are
disposed outwardly of the mounting seat 11, the lubrication oil may
stain the paper, documents, etc. used in the office machine 20.
[0009] (3) There is a need for high precision during manufacture of
the cam surfaces 131, 141 of the bottom and top cam sliding seats
13, 14. The processes required to achieve such high precision
ultimately result in high manufacturing costs of the knuckle arm
10.
SUMMARY OF THE INVENTION
[0010] An object of this invention is to provide a knuckle arm that
can be operated by application of a minimal force.
[0011] Another object of this invention is to provide a knuckle arm
that is used in the opening and closing of a top cover of an office
machine, and that does not directly or indirectly soil the paper,
documents, etc. used in the office machine.
[0012] A further object of this invention is to provide a knuckle
arm that includes only one cam surface requiring high manufacturing
precision.
[0013] Accordingly, a knuckle arm of this invention interconnects a
machine body and a top cover of a machine. In one preferred
embodiment, the knuckle arm includes a base fixed on the machine
body, an inner sliding seat disposed slidably within the base, a
resilient member disposed between the base and the inner sliding
seat, a first pivotable seat sleeved on the base, a pressing rod
extending through the first pivotable seat and kept in contact with
the inner sliding seat, a second pivotable seat disposed slidably
outside the first pivotable seat, a third pivotable seat disposed
pivotally on the second pivotable seat, a first pivot rod, a second
pivot rod and a third pivot rod.
[0014] The base includes a mounting plate unit fixed on the machine
body, two pivot plates connected fixedly to the mounting plate
unit, two first pivot holes formed respectively through the pivot
plates, and a receiving frame. The receiving frame includes a pair
of spaced-apart top and bottom walls that are secured between the
pivot plates and that are inclined relative to the mounting plate
unit, and an abutment wall interconnecting the top and bottom walls
to define an accommodating chamber among the top wall, the bottom
wall, the abutment wall and the pivot plates.
[0015] The inner sliding seat is disposed slidably within the
accommodating chamber along a path inclined relative to the
mounting plate unit, and has a cam surface and an abutment surface
that are opposite to each other.
[0016] The resilient member is disposed within the accommodating
chamber between the abutment wall of the base and the abutment
surface of the inner sliding seat.
[0017] The first pivotable seat includes two first wing plates
located respectively to two opposite sides of an assembly of the
pivot plates, a first connecting plate interconnecting the first
wing plates fixedly, two through holes formed respectively through
the first wing plates, two slots formed respectively through the
first wing plates, two apertures formed respectively through the
first wing plates, and two engagement blocks extending respectively
and integrally from the first wing plates toward each other.
[0018] The pressing rod extends through the through holes in the
first pivotable seat, and is kept in contact with the cam surface
of the inner sliding seat.
[0019] The second pivotable seat includes two second wing plates
located respectively to two opposite sides of an assembly of the
first wing plates of the first pivotable seat, a second connecting
plate interconnecting the second wing plates fixedly, two limiting
plates connected respectively and fixedly to and perpendicular to
the second wing plates to define a limiting chamber among the
second wing plates, the second connecting plates and the limiting
plates, two second pivot holes formed respectively through the
second wing plates, two curved slots formed respectively through
the second wing plates, and two third pivot holes formed
respectively through the second wing plates.
[0020] The first pivot rod extends through the second pivot holes
in the second pivotable seat and the first pivot holes in the
base.
[0021] The third pivotable seat includes two third wing plates
located respectively to two opposite sides of an assembly of the
second wing plates of the second pivotable seat, a coupling plate
interconnecting the third wing plates fixedly and connected fixedly
to the top cover of the machine, two fourth pivot holes formed
respectively through the third wing plates, and two fifth pivot
holes formed respectively through the third wing plates.
[0022] The second pivot rod extends through the fifth pivot holes
in the third pivotable seat and the curved slots in the second
pivotable seat, and presses against the engagement blocks of the
first pivotable seat.
[0023] The third pivot rod extends through the fourth pivot holes
in the third pivotable seat, the third pivot holes in the second
pivotable seat, and the slots in the first pivotable seat.
[0024] Because the inner sliding seat and the resilient member are
disposed within the base, when the top cover is opened or closed by
one hand, the user does not have to support the weight of the inner
sliding seat or the resilient member. Thus, the top cover can be
operated in a manner requiring the user to exert a minimal force.
Furthermore, because the inner sliding seat is disposed within the
base, lubrication oil is applied within the base. Thus, the
staining of paper, documents, etc, by the lubrication oil can be
prevented during use of the office machine.
[0025] In addition, the knuckle arm has only one cam surface, and
therefore can be easily manufactured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other features and advantages of this invention
will become apparent in the following detailed description of a
preferred embodiment of this invention, with reference to the
accompanying drawings, in which:
[0027] FIG. 1 is a sectional side view of a conventional knuckle
arm disclosed in U.S. Pat. No. 6,456,365;
[0028] FIG. 2 is an exploded sectional view of the preferred
embodiment of a knuckle arm according to this invention;
[0029] FIG. 3 is a perspective view of a base of the preferred
embodiment;
[0030] FIG. 4 is a perspective view of an inner sliding seat of the
preferred embodiment;
[0031] FIG. 5 is a perspective view of a first pivotable seat of
the preferred embodiment;
[0032] FIG. 6 is a perspective view of a second pivotable seat of
the preferred embodiment;
[0033] FIG. 7 is a perspective view of a third pivotable seat of
the preferred embodiment;
[0034] FIG. 8 is a sectional side view of the preferred embodiment,
illustrating how a top cover of the copier is closed;
[0035] FIG. 9 is a sectional side view of the preferred embodiment,
illustrating how the top cover of the copier is opened to an angle
ranging between 30 and 90 degrees;
[0036] FIG. 10 is a sectional side view of the preferred
embodiment, illustrating how the top cover of the copier is opened
to an angle of about 90 degrees;
[0037] FIG. 11 is a sectional side view of the preferred
embodiment, illustrating the position of the top cover of the
copier when manipulation of a thick document is required; and
[0038] FIG. 12 is a graph showing the distribution of a spring
torque and a gravitational torque as a function of an opening angle
of the top cover.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0039] Referring to FIGS. 2 and 8, the preferred embodiment of a
knuckle arm according to this invention interconnects a machine
body 31 and a top cover 32 of an office machine 30, and is
constructed so as to allow for the opening and closing of the top
cover 32 relative to the machine body 31. The office machine may be
a copier, scanner, etc.
[0040] The knuckle arm includes a base 40, an inner sliding seat 50
disposed slidably within the base 40, four resilient members 60
(only two are shown in FIGS. 2 and 8) disposed between the base 40
and the inner sliding seat 50, a first pivotable seat 70 disposed
pivotally on the base 40, a pressing rod 100 extending through the
first pivotable seat 70 and kept in contact with a cam surface 51
of the inner sliding seat 50, a second pivotable seat 80 sleeved on
the first pivotable seat 70, a third pivotable seat 90 disposed
pivotally on the second pivotable seat 80, a first pivot rod 101
extending through the second pivotable seat 80 and the base 40, a
second pivot rod 102, and a third pivot rod 103. Each of the second
and third pivot rods 102, 103 extends through the first, second and
third pivotable seats 70, 80, 90.
[0041] Referring to FIGS. 2 and 3, the base 40 includes a mounting
plate unit consisting of two coplanar mounting plates 41, two pivot
plates 42 formed respectively and integrally with and perpendicular
to the mounting plates 41, two first pivot holes 43 formed
respectively through the pivot plates 42, and a receiving frame 44
secured between the pivot plates 42. The receiving frame 44
includes a top wall 441, a bottom wall 442 and an abutment wall
443. The top and bottom walls 441, 442 are secured between the
pivot plates 42, are inclined relative to the mounting plates 41,
and are spaced apart from each other. The abutment wall 443 has two
opposite sides formed respectively and integrally with the top and
bottom walls 441, 442. An accommodating chamber 444 is therefore
defined among the top wall 441, the bottom wall 442, the abutment
wall 443 and the pivot plates 42.
[0042] Referring to FIGS. 2 and 4, the inner sliding seat 50 can
slide within the accommodating chamber 444 along a path inclined
relative to the mounting plates 41. The inner sliding seat 50 has a
cam surface 51, and an abutment surface 52 that is opposite to the
cam surface 51 and that faces the abutment wall 443 of the base 40.
The inner sliding seat 50 further includes four engagement walls 53
(only two is shown in FIG. 4) and four annular flanges 54. Each of
the engagement walls 53 and the annular flanges 54 extends from the
abutment surface 52 toward the abutment wall 443 of the base 40.
The engagement walls 53 abut respectively against the top wall 441,
the bottom wall 442 and the pivot plates 42. Therefore, the inner
sliding seat 50 is guided to move within the accommodating chamber
444 along a direction. The cam surface 51 has opposite first and
second ends 511, 512, and a convex middle portion 513 disposed
between the first and second ends 511, 512.
[0043] Each of the resilient members 60 is configured as a coiled
compression spring, is disposed within the accommodating chamber
444, and has a first end foot 61 pressing against the abutment wall
443 of the base 40, and a second end foot 62 sleeved on the
corresponding annular flange 54 in a close-fitting manner and
pressing against the abutment surface 52 of the inner sliding seat
50. As such, the inner sliding seat 50 is biased by the springs 60
to move away from the abutment wall 443 of the base 40.
[0044] Referring to FIGS. 2 and 5, the first pivotable seat 70
includes two first wing plates 71 located respectively to two
opposite sides of an assembly of the pivot plates 42 of the base
40, a first connecting plate 72 interconnecting the first wing
plates 71 fixedly, two through holes 73 formed respectively through
the first wing plates 71, two slots 74 formed respectively through
the first wing plates 71, two apertures 75 formed respectively
through the first wing plates 71, and two aligned engagement blocks
76 extending respectively and integrally from the first wing plates
71 toward each other. Each of the slots 74 has a first end 741
proximate to the base 40, and a second end 742 opposite to the
first end 741 and distal from the base 40.
[0045] Referring to FIG. 8, the pressing rod 100 extends through
the through holes 73 in the first pivotable seat 70, and is kept in
contact with the cam surface 51 of the inner sliding seat 50 due to
the biasing action of the resilient members 60.
[0046] Referring to FIGS. 2 an 6, the second pivotable seat 80
includes two second wing plates 81 located respectively to two
opposite sides of an assembly of the first wing plates 71 of the
first pivotable seat 70, a second connecting plate 82
interconnecting the second wing plates 81 fixedly, two limiting
plates 83 formed respectively and integrally with and perpendicular
to the second wing plates 81, two second pivot holes 85 formed
respectively through the second wing plates 81, two curved slots 86
formed respectively through the second wing plates 81, and two
third pivot holes 87 formed respectively through the second wing
plates 81. A limiting chamber 84 is defined among the second wing
plates 81, the second connecting plate 82 and the limiting plates
83. The first pivotable seat 70 is limited to move within the
limiting chamber 84. Each of the curved slots 86 has a first end
861 proximate to the base 40, and a second end 862 opposite to the
first end 861 and distal from the base 40.
[0047] Referring to FIG. 8, the first pivot rod 101 extends through
the second pivot holes 85 in the second pivotable seat 80 and the
first pivot holes 43 in the base 40.
[0048] Referring to FIGS. 2 and 7, the third pivotable seat 90
includes two third wing plates 91 located respectively to two
opposite sides of an assembly of the second wing plates 81 of the
second pivotable seat 80, a mounting plate 92 interconnecting the
third wing plates 91 and connected fixedly to the top cover 32 (see
FIG. 8), two fourth pivot holes 93 formed respectively through the
third wing plates 91, and two fifth pivot holes 94 formed
respectively through the third wing plates 91.
[0049] The second pivot rod 102 extends through the fifth pivot
holes 94 in the third pivotable seat 90, the curved slots 86 in the
second pivotable seat 80 and the apertures 75 in the first
pivotable seat 70. The second pivot rod 102 presses against the
engagement blocks 76 of the first pivotable seat 70.
[0050] The third pivot rod 103 extends through the fourth pivot
holes 93 in the third pivotable seat 90, the third pivot holes 87
in the second pivotable seat 80 and the slots 74 in the first
pivotable seat 70.
[0051] Referring to FIGS. 8 and 12, a spring force applied to the
inner sliding seat 50 by the resilient members 60 is transmitted to
the pressing rod 100, the first pivotable seat 70, the engagement
blocks 76, the second pivot rod 102, the third pivotable seat 90
and the top cover 32. As such, the resilient members 60 produce a
counterclockwise spring torque (A) on the first pivot rod 101, and
the top cover 32 produces a clockwise gravitational torque (B) on
the first pivot rod 101. Each of the spring torque (A) and the
gravitational torque (B) changes according to the position of the
inner sliding seat 50 within the accommodating chamber 444 in the
receiving frame 44. FIG. 12 shows changes in the spring torque (A)
and the gravitational torque (B) as a function of the opening angle
of the top cover 32.
[0052] When the top cover 32 is closed (i.e. when the opening angle
of the top cover 32 is zero), the gravitational torque (B) is
greater than the spring torque (A). Thus, the top cover 32 is
maintained at the closed position. At this time, the pressing rod
100 is in contact with the first end 511 of the cam surface 51.
[0053] Referring to FIGS. 2, 9, and 12, when the top cover 32 is
pivoted upwardly from the closed position, the positions of the
third pivotable seat 90, the second pivot rod 102, the third pivot
rod 103, the second pivotable seat 80, the first pivotable seat 70,
and the pressing rod 100 relative to the base 40 are changed. The
opening of the top cover 32 results in movement of the pressing rod
100 from the first end 511 of the cam surface 51 toward the second
end 512 of the cam surface 51. When the top cover 32 is opened to
an angle of 30 degrees, the gravitational torque (B) is equal to
the spring torque (A), as shown in FIG. 12. As a consequence, when
released, the top cover 32 is maintained at the 30.degree. open
position. At this time, the pressing rod 100 is in contact with the
convex middle portion 513 of the cam surface 51.
[0054] The curves of the spring torque (A) and the gravitational
torque (B) in FIG. 12 also intersect at two other positions, at
which the opening angles of the top cover 32 are 45 and 90 degrees,
respectively. Hence, the top cover 32 is self-positioning.
[0055] The top cover 32 can be easily moved from the 30.degree.
open position to a 90.degree. open position shown in FIG. 10 in
view of the fact that the pressing rod 100 easily slides from the
convex middle portion 513 of the cam surface 51 to the second end
512 of the cam surface 51 during this period.
[0056] During movement of the top cover 32 from the closed position
to the 90.degree. open position, the third pivot rod 103 is kept at
the first ends 741 of the slots 74, and the second pivot rod 102 is
kept at the second ends 862 of the curved slots 86.
[0057] When a thick document (not shown) is used in the office
machine 30 (see FIG. 8), the top cover 32 is turned downwardly from
the 90.degree. open position toward the closed position. At the
same time, the pressing rod 100 moves from the second end 512 of
the cam surface 51 toward the convex middle portion 513 of the cam
surface 51. As a result, the second pivot rod 102 moves from the
second ends 862 of the curved slots 86 to the first ends 861 of the
curved slots 86, as shown in FIG. 11. Hence, the first pivotable
seat 70 moves within the limiting chamber 84 in the second
pivotable seat 80 in a direction toward the inner sliding seat 50
so as to move the inner sliding seat 50 toward the abutment wall
443 of the base 40. At the same time, the third pivot rod 103 moves
from the first ends 741 of the slots 74 to the second ends 742 of
the slots 74. When the top cover 32 rests on the thick document
(not shown), the gravitational torque (B) is greater than the
spring torque (A), thereby maintaining the positioning of the top
cover 32 on the thick document.
[0058] Alternatively, the top cover 32 may be mounted directly to
the second pivotable seat 80. In this case, the third pivot rod
103, the third pivotable seat 90, the third pivot holes 87 in the
second pivotable seat 80, and the slots 74 in the first pivotable
seat 70 are omitted. This still allows for the self-positioning of
the top cover 32.
[0059] The knuckle arm of this invention has the following
advantages: [0060] (1) When the top cover 32 is opened or closed by
one hand, only the combined weight of the top cover 32, the third
pivotable seat 90, the second pivotable seat 90, the second
pivotable seat 80, the first pivotable seat 70, the second pivot
rod 102, the third pivot rod 103 and the pressing rod 100 need be
supported by the user. Because the user does not have to support
the weight of the inner sliding seat 50 or the resilient members
60, the top cover 32 can be opened or closed in a manner requiring
the user to exert only a minimal force. [0061] (2) Because the
inner sliding seat 50 is concealed within the receiving frame 44 of
the base 40, lubrication oil applied to the inner sliding seat 50
is contained within the base 40, thereby preventing the staining of
paper, documents, etc. by the lubrication oil. [0062] (3) There is
a need for high precision during manufacture of a cam surface.
Since the knuckle arm of this invention includes only one cam
surface 51, there is realized a reduction in the manufacturing
costs of the knuckle arm of this invention in comparison with the
conventional knuckle arm 10 (see FIG. 1).
[0063] Therefore, the objects of this invention can be
achieved.
[0064] With this invention thus explained, it is apparent that
numerous modifications and variations can be made without departing
from the scope and spirit of this invention. It is therefore
intended that this invention be limited only as indicated by the
appended claims.
* * * * *