Information
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Patent Grant
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6772703
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Patent Number
6,772,703
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Date Filed
Monday, July 14, 200320 years ago
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Date Issued
Tuesday, August 10, 200419 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
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CPC
-
US Classifications
Field of Search
US
- 112 66
- 112 70
- 112 73
- 112 65
- 112 1025
- 112 103
- 112 47006
- 112 446
- 112 447
- 112 448
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International Classifications
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Abstract
An eye-type buttonhole sewing machine comprises an x-y table with an x carriage which is guided on the sewing machine and on which a y carriage is displaceably guided, having a bearing plate. Actuation of the x carriage is effected by an x motor which is mounted on the sewing machine and directly coupled with the x carriage via a cam drive. Actuation of the y carriage is equally effected via an electric motor which is directly connected to the y carriage via a threaded spindle with a spindle nut and a sliding coupling.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an eye-type buttonhole sewing machine.
2. Background Art
U.S. Pat. No. 6,095,066 describes an eye-type buttonhole sewing machine with a needle drivable in up and down reciprocation. It comprises an x-y table which is displaceable by stationary stepper motors mounted on the sewing machine. The x-y table is supported by way of vertical, parallel rods so that displacement in the x direction is arched. Actuation in the x direction is effected via a toothed quadrant that is coupled with a shaft with an oscillating lever mounted thereon. Actuation in the y direction takes place via an electric motor by means of a threaded spindle which runs in the y direction and the spindle nut of which is joined to the y carriage by a sliding coupling. Drawbacks reside in that accurate working of the stitch-forming tools i.e., of the needle, hook etc., is restricted or, for greater displacements, not at all attainable due to the fact that the guidance of the table is acceptable only with some reservations. Further drawbacks reside in that a considerable number of components is required, having a corresponding mass, which demands for strong dimensioning of the stepper motors.
Prior public use by Applicant has disclosed an eye-type buttonhole sewing machine in which an x-y table of the above design is drivable in the y direction by a belt drive. The oscillating levers which perform the motion in the x direction are drivable by a cam drive. The design has the additional drawback that the belt drive possesses a certain elasticity, allowing accurate positioning only to a certain extent.
SUMMARY OF THE INVENTION
It is an object of the invention to embody an eye-type buttonhole sewing machine in which motion in the x and y direction may take place very easily and accurately.
According to the invention, this object is attained in an eye-type buttonhole sewing machine, comprising a needle which is drivable in up and down reciprocation; an x-y table which supports an x carriage mounted on the sewing machine for displacement only in an x direction, and a y carriage mounted on the x carriage for displacement only in a y direction; an x motor in the form of an electric motor mounted on the sewing machine, which x motor is directly coupled with the x carriage via a drive that translates a rotary motion into a linear motion; and a y motor in the form of an electric motor mounted on the sewing machine, which y motor is directly connected to the y carriage via a threaded spindle and a spindle nut and a sliding coupling which extends in the x direction. The design according to the invention helps accomplish that the x-y table, with a work piece resting thereon, is guided precisely on an x-y level, not performing any vertical motion perpendicular thereto. With the drive which converts the rotary motion into a linear motion acting directly on the x carriage, components are saved and actuation virtually free from play is rendered possible. Likewise, the y drive is free from play because of direct conversion. Since the drives act directly on the respective x and y carriage in the x and y direction, also the mass of conversion elements is low so that strong acceleration and high positioning accuracy are attained, accompanied with driving motors of correspondingly restricted design.
Details of the invention will become apparent from the ensuing description of an exemplary embodiment, taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1
is a side view of an eye-type buttonhole sewing machine;
FIG. 2
is a vertical sectional view of the x-y table of the sewing machine on the line II—II of
FIG. 1
;
FIG. 3
is a substantially vertical sectional view of the x-y table on the line III—III of
FIG. 2
;
FIG. 4
is a substantially vertical sectional view of the x-y table on the line IV—IV of
FIG. 2
;
FIG. 5
is a plan view of the x-y table, with the bearing plate that rests thereon being roughly outlined by dot-dashed lines;
FIG. 6
is an illustration of the x drive of the x-y table on the line VI—VI of
FIG. 4
; and
FIG. 7
is a diagrammatic view of the kinematics of the x-y table.
DESCRIPTION OF A PREFERRED EMBODIMENT
As seen in
FIG. 1
, an eye-type buttonhole sewing machine is C-shaped, which means it has a top arm
1
, a bottom base plate
2
in the form of a casing, and a vertical standard
3
connecting the two. An arm shaft
4
is conventionally run in the arm
1
; it is actuated by a driving motor
5
by means of a belt drive
6
. Actuation of a needle bar
7
, which has a needle
8
and is movable vertically in the z direction, and a jogging drive therefor are conventionally derived from the arm shaft
4
. A hook bearing
9
, which is disposed in the base plate
2
, is allocated to the needle bar
7
. The needle bar
7
is mounted on a pivot bearing
10
, in which it pivots about its longitudinal axis
11
together with the hook bearing
9
for so-called eye-type buttonholes to be produced. Pivoted actuation of the pivot bearing
10
i.e., of the needle bar
7
with needle
8
and the hook bearing
9
, is effected by a joint drive (not shown), of which is illustrated only a timing belt
12
that leads to the pivot bearing
10
. The design of the pivot bearing
10
is known for instance from U.S. Pat. No. 6,095,066, which reference is made to.
An x-y table
13
is disposed on the base plate
2
; it is a cross slide movable in two horizontal coordinate directions, namely the x direction and the y direction. It comprises a bearing plate
14
with a work piece clamp
15
disposed thereon, having a clamping plate
17
that is mounted on a pivotable bearing lever
16
. Details of the structure and actuation of such a work piece clamp
15
will become apparent from U.S. patent application Ser. No. 10/410,466, which reference is made to in this regard. Located downstream of the needle bar
7
in the y direction is a buttonhole cutting device
18
, which is only roughly outlined in FIG.
1
. Structure and operation of such a buttonhole cutting device are described for example in U.S. Pat. No. 4,552,080. Clamped between the clamping plate
17
and the bearing plate
14
is a work piece (not shown) which is to be provided with a buttonhole that will then be cut up by means of the buttonhole cutting device
18
.
Design and actuation of the x-y table
13
will be described below. It comprises an x carriage
19
which is displaceable on the base plate
2
, and a y carriage
20
that is displaceable in the y direction on the x carriage
19
. The x carriage
19
comprises two parallel x guide bars
21
,
22
which run in the x direction and are displaceable in two x sliding bearings
23
which are stationary on the base plate
2
. The two x guide bars
21
,
22
are assembled in the vicinity of their free ends by means of ties
24
. They are also joined to y guide bars
25
,
26
which run in the x direction i.e., they are horizontal like the x guide bars
21
,
22
, however extending perpendicular thereto. The x guide bars
21
,
22
and the y guide bars
25
,
26
combine with the ties
24
to form the x carriage
19
which is rectangular in a plan view. The x guide bar
22
is disposed in the standard
3
.
y sliding bearings
27
are formed on the bottom side of the bearing plate
14
, with two of them at a time being disposed on each y guide bar
25
,
26
so that the bearing plate
14
combines with the y sliding bearings
27
, forming the y carriage
20
.
Actuation of the x carriage
19
in the x direction takes place by an x motor
28
which is mounted on the base plate
2
and the driven shaft
29
of which is drivable in rotation about a vertical axis
30
. A cam disk
31
is mounted on the driven shaft
29
, having a cam curve in the form of a guiding groove
32
that spirals in relation to the axis
30
. A driver
33
is clampingly fixed to the y guide bar
26
, on its bottom side having a driving roller
34
which engages with the guiding groove
32
. Owing to the arrangement of the guiding groove
32
in relation to the stationary axis
30
of the x motor
28
, the x carriage
19
, upon rotary or pivoted actuation of the cam disk
31
about the axis
30
, is moved in the x direction, with the maximal length of displacement i.e., the maximal lift of the x carriage
19
being in the range of approximately 8 mm. Consequently, the cam disk
31
and the driver
33
form a cam drive
35
, which translates the rotary motion of the x motor
28
into a linear motion of the x carriage
19
.
The y carriage
20
is driven by a y motor
36
which is disposed in the standard
3
and the driven shaft
37
of which, via a coupling
38
, is connected to a threaded spindle
39
which runs in the y direction. The threaded spindle
39
is rotatably housed in bearings
40
which are mounted on the base plate
2
. A spindle nut
41
is mounted on the threaded spindle
39
; it is connected to the y carriage
20
by means of a sliding coupling
42
. To this end, aligned pins
43
,
44
are mounted on the spindle nut
41
; they extend in the x direction and engage with guide holes
45
of two driving arms
46
,
47
which are mounted on the bottom side of the bearing plate
14
. The pins
43
,
44
are sufficiently long and the driving arms
46
,
47
are sufficiently spaced from the spindle nut
41
for the pins
43
and
44
to be shifted in the respective driving arm
46
and
47
by the maximal length of displacement s of the x carriage
19
in the x direction upon corresponding displacements by way of the cam drive
35
. Displacement of the y carriage
20
in the y direction takes place by rotary actuation of the y motor
36
via the threaded spindle
39
and the spindle nut
41
and the sliding coupling
42
. The usual length of displacement in the y direction is for example 30 mm.
The x motor
28
and the y motor
36
are electric motors, preferably stepper motors or motors with rotary position feedback. In the same way as the driving motor
5
, they are connected via corresponding control lines
48
,
49
,
50
to a control unit
51
where the control data are recorded.
Claims
- 1. An eye-type buttonhole sewing machine, comprisinga needle (8) which is drivable in up and down reciprocation; an x-y table (13) which supports an x carriage (19) mounted on the sewing machine for displacement only in an x direction, and a y carriage (20) mounted on the x carriage (19) for displacement only in a y direction; an x motor (28) in the form of an electric motor mounted on the sewing machine, which x motor (28) is directly coupled with the x carriage (19) via a drive that translates a rotary motion into a linear motion; and a y motor (36) in the form of an electric motor mounted on the sewing machine, which y motor (36) is directly connected to the y carriage (20) via a threaded spindle (39) and a spindle nut (41) and a sliding coupling (42) which extends in the x direction.
- 2. An eye-type buttonhole sewing machine according to claim 1, wherein the drive is in the form of a cam drive (35) and includes a cam (31) which is joined to a driven shaft (29) of the x motor (28), and which cam has a guiding groove (32) that spirals in relation to the axis (30) of the x motor (28), and which cam has a driver (33) which is directly joined to the x carriage (19) and engages with the guiding groove (32).
- 3. An eye-type buttonhole sewing machine according to claim 2, wherein the cam disk (31) is directly mounted on the x motor (28).
- 4. An eye-type buttonhole sewing machine according to claim 1, wherein the sliding coupling (42) comprises at least one pin (43, 44) which is mounted on the spindle nut (41) and engages with a guide hole (45) of a driving arm (46, 47) provided on the y carriage (20).
- 5. An eye-type buttonhole sewing machine according to claim 1, wherein the x carriage (19) is a frame, having y guide bars (25, 26) which are guided on the sewing machine and support the y carriage (20).
Priority Claims (1)
Number |
Date |
Country |
Kind |
102 33 017 |
Jul 2002 |
DE |
|
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
34 26 687 |
Jan 1985 |
DE |
G 85 07 830.1 |
Jul 1987 |
DE |