Information
-
Patent Grant
-
6745474
-
Patent Number
6,745,474
-
Date Filed
Tuesday, December 17, 200222 years ago
-
Date Issued
Tuesday, June 8, 200420 years ago
-
Inventors
-
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 030 162
- 030 335
- 030 151
- 030 329
- 030 125
-
International Classifications
-
Abstract
A cutting knife includes a holder with a slot defined in a side thereof and a plurality of recesses defined in one of two sides of the slot. A base member is slidably engaged with the slot and a blade is connected to the base member. The base member has a wall in which a spring member is received. The spring member includes a protrusion which extends through an opening defined in the wall and is engaged with one of the recesses. A spring is biased between an inside of the wall and a reverse side of the protrusion of the spring member so as to provide a force to engage the protrusion in the recess. Two end portions of the spring member contact against the insides of the wall. An operation member is slidably mounted to the wall and includes a wedge-shaped notch which may push the protrusion downward to disengage from the recess.
Description
FIELD OF THE INVENTION
The present invention relates to a blade pushing device of a cutting knife wherein the spring member has two ends contacting against two insides of the body member so as to prevent the spring member from being fatigue fast.
BACKGROUND OF THE INVENTION
A conventional cutting knife
10
is shown in
FIGS. 1 and 2
and in U.S. Pat. No. 6,226,873. A slider
13
is slidably engaged with the slot
111
of the holder
11
. A blade
12
is connected to the base plate, of the slider
13
and a leaf spring
133
is received in a chamber
131
A of a body member
131
of the slider
13
. The leaf spring
133
includes a protrusion
133
A that retractably extends through a notch of the body member
131
so as to be engaged with one of the recesses
111
A defined in the inside of the slot
111
. An operation member
132
is movably mounted to the body member
131
and has a wedge-shaped notch
132
A which may push the protrusion
133
A of the leaf spring
133
downward to disengage the protrusion
133
A from the recess
111
A so that the blade
12
can be moved till the protrusion
133
A is engaged with another recess
111
A. The two ends of the leaf spring
133
have no stop means to limit their deformation and shifting so that the deformation of the leaf spring
133
is not under control and this makes the leaf spring
133
to reach its limitation of fatigue more quickly than expected.
The present invention intends to provide an improved blade pushing device for a cutting knife and the two ends of the spring member are stopped by two insides of the body such that the deformation of the spring member can be well controlled.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a cutting knife that has a spring member received in a base member which is slidably engaged with the slot in the holder, a spring is biased between an inside of the wall and the reverse side of the protrusion of the spring member so as to provide a force to engage the protrusions with one of the recesses defined in one of two sides of the slot.
Another object of the present invention is to provide a cutting knife wherein the spring member has two end portions which contact against the insides of the wall so as to limit the deformation n of the spring member when the protrusion of the spring member is pushed to disengage from the opening of the wall of the base member.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a side view to show a conventional cutting knife;
FIG. 2
is a cross sectional view to show the conventional pushing device of the conventional cutting knife;
FIG. 3
is a perspective view to show the cutting knife of the present invention;
FIG. 4
is an exploded view to show the cutting knife of the present invention;
FIG. 5A
shows the protrusion of the spring member is engaged with a recess of the slot;
FIG. 5B
shows the operation member is pushed to push the protrusion off from the recess;
FIG. 5C
shows the protrusion is completely disengaged from the recess;
FIG. 5D
shows the protrusion is engaged with another recess;
FIG. 6A
shows the operation member has two rails slidably mounted to the grooves of the wall on the base member;
FIG. 6B
is an end cross sectional view to show the protrusion is engaged with a recess, and
FIG. 6C
shows the protrusion is pushed by moving the operation member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to
FIGS. 3
,
4
and
5
A, the cutting knife of the present invention comprises a holder
20
having a slot
21
defined in a side thereof and a plurality of recesses
211
are defined in one of two sides defining the slot
21
. An end piece
50
is engaged with an opening at one end of the holder
20
and a blade
30
is movably inserted in the holder
20
via the other opening at the other end of the holder
20
.
A pushing assembly
40
includes a base member
41
which is slidably received in the slot
21
by engaging two side flanges
411
with the slot
21
. A plate
410
extends from a front end of the base member
41
and a boss extends from a side of the plate
410
so as to be engaged with a hole defined through the blade
30
. A wall
412
extends from a side of the base member
40
and an opening
412
C is defined through the wall
412
. A rod
412
B extends from an inside of the wall
412
and a first end of a spring
42
is mounted to the rod
412
B. Two stops
412
E extend from an edge of the wall
412
and located at two ends of the wall
412
.
A spring member
43
is received in a space
412
A enclosed by the wall
412
and has a protrusion
431
engaged with the opening
412
C in the wall
412
. A second end of the spring
42
contacts a reverse, side
433
of the protrusion
421
of the spring member
43
. The protrusion
431
of the spring member
43
is pushed by the spring
42
and engaged with one of the recesses
211
of the slot
21
of the holder
20
. Two end portions
432
extend from two ends of a main portion of the spring member
43
and contact against two insides of the wall
412
.
Further referring to
FIG. 6A
, an operation member
44
has two side walls and each of the side walls has a rail
443
which is slidably engaged with grooves
412
D defined in the outside of the wall
412
so that the operation member
44
is movably mounted to the outside of the wall
412
by pushing a rough surface
441
on the top surface of the operation member
44
. A convex portion
442
extends from an inside of the operation member
44
and two ends of the convex portion
442
are movable between the two stops
412
E on the wall
412
. A wedge-shaped notch
444
is defined in a side of the operation member
44
and the protrusion
431
of the spring member
43
is engaged with the wedge-shaped notch
444
.
Referring to
FIGS. 5B
to
5
D,
6
B and
6
C, when pushing the operation member
44
toward the blade
30
, the protrusion
431
is pushed downward by the side of the wedge-shaped notch
444
so that the spring member
43
is deformed and the protrusion
431
is disengaged from the recess
211
. The operation member
44
can then be pushed with the blade
30
while holding the position of the operation member
44
relative to the protrusion
431
of the spring member
43
, till a desired position, the protrusion
431
is biased to engage with another recess
211
.
The two end portions
432
are supported by the insides of the wall
412
so that the spring member
43
will not be deformed too much and this may prevent the spring member
43
from reaching its point of fatigue too fast. Besides, the spring
42
provides a firm engagement of the protrusion
431
and the recess
211
such that the blade
30
can be fixed relative to the holder
20
when using the blade
30
to cut a stiff object.
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
Claims
- 1. A cutting knife comprising:a holder having a slot defined in a side thereof and a plurality of recesses defined in one of two sides defining the slot; a base member slidably received in the slot and having a plate extending from a front end thereof, a boss extending from a side of the plate and a blade received in the slot and engaged with the boss, a wall extending from a side of the base member and an opening defined through the wall, a rod extending from an inside of the wall and a first end of a spring mounted to the rod, two stops extending from an edge of the wall; a spring member having a protrusion engaged with the opening in the wall and a second end of the spring contacting a reverse side of the protrusion of the spring member, the protrusion of the spring member engaged with one of the recesses of the slot of the holder, two end portions extending from a main portion of the spring member and contacting against two insides of the wall, and an operation member movably mounted to an outside of the wall and a convex portion extending from an inside of the operation member, two ends of the convex portion being movable between the two stops on the wall, a wedge-shaped notch defined in a side of the opt ration member and the protrusion of the spring member engaged with the wedge-shaped notch.
US Referenced Citations (13)