U.S. patent application number 09/876777 was filed with the patent office on 2002-01-31 for reciprocating type thread rolling apparatus.
This patent application is currently assigned to Aoyama Seisakusho Co., Ltd.. Invention is credited to Kato, Atsushi, Kato, Keigo, Mizuno, Masataka, Taniguchi, Naoshige.
Application Number | 20020013178 09/876777 |
Document ID | / |
Family ID | 18678341 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020013178 |
Kind Code |
A1 |
Kato, Keigo ; et
al. |
January 31, 2002 |
Reciprocating type thread rolling apparatus
Abstract
The present invention relates to a reciprocating type thread
rolling apparatus and comprises a ram reciprocated by a crank shaft
and fixing to one side thereof at least two moving dies, the other
side of the ram being disposed along a single thread rolling
pressure bearing block, and stationary dies adapted to pair with
the moving dies for thread rolling, the stationary dies being the
same in number as that of the moving dies and disposed to be
opposite to the moving dies.
Inventors: |
Kato, Keigo; (Niwa-gun,
JP) ; Mizuno, Masataka; (Niwa-gun, JP) ; Kato,
Atsushi; (Niwa-gun, JP) ; Taniguchi, Naoshige;
(Kasugai-shi, JP) |
Correspondence
Address: |
FRISHAUF, HOLTZ, GOODMAN &
LANGER & CHICK, PC
767 THIRD AVENUE
25TH FLOOR
NEW YORK
NY
10017-2023
US
|
Assignee: |
Aoyama Seisakusho Co., Ltd.
101-2, Yagotohonmachi, Showa-ku
Nagoya-shi
JP
|
Family ID: |
18678341 |
Appl. No.: |
09/876777 |
Filed: |
June 7, 2001 |
Current U.S.
Class: |
470/57 |
Current CPC
Class: |
B21H 3/06 20130101 |
Class at
Publication: |
470/57 |
International
Class: |
B21K 001/44 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2000 |
JP |
176637/2000 |
Claims
1. A reciprocating type thread rolling apparatus comprising a ram 7
reciprocated by a crank shaft and fixing to one side thereof at
least two moving dies 10a, 10b, the other side of the ram being
disposed along a single thread rolling pressure bearing block, and
stationary dies 9a, 9b adapted to pair with the moving dies for
thread rolling, the stationary dies being the same in number as
that of the moving dies and disposed to be opposite to the moving
dies.
2. The reciprocating type thread rolling apparatus according to
claim 1, wherein the ram 7 is divided into at least two rams 7a, 7b
and the moving dies 10a, 10b, respectively, are arranged on the
respective rams.
3. The reciprocating type thread rolling apparatus according to
claim 2, wherein the moving die 10a is not arranged on the ram 7a
and the at least two moving dies 10a, 10b are arranged on the ram
7b.
4. The reciprocating type thread rolling apparatus according to
claim 3, wherein the ram 7b is further divided into at least two
rams, and the moving dies 10a, 10b are arranged on each of the rams
as divided.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to an apparatus for rolling a thread
(hereinafter referred to as thread rolling) mounting thereon a flat
die composed of a stationary die and a reciprocating moving
die.
[0002] Conventionally, a flat die type thread rolling apparatus for
performing thread rolling by means of a moving die mounted on a
reciprocating ram and a stationary die mounted on a base causes a
problem that productivity is low since the moving die is
reciprocated to subject one bolt stock to thread rolling. Hereupon,
the inventors of the present application have devised a thread
rolling apparatus, in which flat dies composed of a stationary die
and a moving die are arranged in a zigzag manner with a ram
therebetween, as disclosed in Japanese Provisional Patent
Publication No. 11-151545. More specifically, with the apparatus,
one of the flat dies can perform thread rolling when the ram
advances, and the other of the flat dies can perform thread rolling
when the ram retreats, and thus thread rolling can be applied on
two bolt stocks in one reciprocation of the ram to considerably
enhance productivity.
[0003] However, it has proved that the thread rolling apparatus, in
which the flat dies are arranged in a zigzag manner with the ram
therebetween, involves the following defects.
[0004] Thread rolling load is acted on the ram at the time of
thread rolling. Since the thread rolling pressure bearing block is
divided into two halves, which are small in pressure receiving area
to be insufficient in rigidity to be liable to cause backward
bending deformation on the ram, thus resulting in a degraded
accuracy of threads as formed.
[0005] Commonly, the set-up work is performed on the stationary die
at the time of thread rolling. Since the flat dies are arranged in
a zigzag manner, it is necessary to move to the opposite side,
which makes workability worse.
[0006] Since there is a need of setting-up spaces on the opposite
side at the time of bolt thread rolling, there must be a large work
space.
SUMMARY OF THE INVENTION
[0007] The invention has been devised to solve the above-mentioned
problems of the prior art and to provide a reciprocating type
thread rolling apparatus, which involves high accuracy for threads
and favorable workability at the time of setting-up and which does
not require any large setting-up adjusting space.
[0008] That is, a reciprocating type thread rolling apparatus
according to the invention comprises a ram reciprocated by a crank
shaft and fixing to one side thereof at least two moving dies, the
other side of the ram being disposed along a single thread rolling
pressure bearing block, and stationary dies adapted to pair with
the moving dies for thread rolling, the stationary dies being the
same in number as that of the moving dies and disposed to be
opposite to the moving dies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a plan view showing an embodiment of the
invention.
[0010] FIG. 2 is a plan view showing another embodiment of the
invention.
[0011] FIG. 3 is a plan view showing a still further embodiment of
the invention.
1 Explanation of characters 1 drive mechanism 2 base 3 pulley 4
small gear 5 large gear 6 connecting rod 7, 7a, 7b ram 8 connecting
member 9, 10 flat die 9a, 9b stationary die 10a, 10b moving die 11
thread rolling pressure bearing block 12, 13 part feeder 14, 15
guide rail 16, 17 projection plate 18a, 18b upper cover 19a, 19b
die block bearing frame
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The invention will be described below in detail with
reference to the drawings, in which typical embodiments of the
invention are shown.
[0013] FIG. 1 shows an embodiment of the invention, the reference
numeral 1 denoting a drive mechanism provided on a base 2, the
drive mechanism comprising a pulley 3 driven through a belt by a
motor (not shown) or the like, a small gear 4 mounted on a shaft of
the pulley, and a large gear 5 for meshing with the small gear.
[0014] A connecting rod 6 for converting torque of the large gear
into reciprocation of a ram 7 is pivoted at one end thereof in an
eccentric position on a side of the large gear, and at the other
end thereof on the ram.
[0015] The reference numeral 9 denotes a flat die composed of
stationary dies 9a, 9b, which are detachably mounted on the base 2
on the same side of the ram 7 through die block bearing frames 19a,
19b. The reference numeral 10 denotes a flat die composed of moving
dies 10a, 10b, which are detachably mounted on one side of the ram
7 to face the stationary dies (the moving die 10a pairs with the
stationary die 9a while the moving die 10b pairs with the
stationary die 9b. In addition, while two sets of the stationary
die and the moving die are shown in the figure, they may be
suitably set taking account of freedom in arrangement of the
apparatus, manufacturing cost of the ram, weight of the apparatus,
and the like. The same may be said of the rest.).
[0016] A single thread rolling pressure bearing block 11 for
preventing backward bending deformation of the ram 7 at the time of
thread rolling is mounting to the base 2 on an opposite surface of
the ram 7 to a surface, on which the moving dies 10a, 10b are
mounted, whereby the block bears thread rolling pressure acting on
the ram.
[0017] The respective sets (9a, 10a), (9b, 10b) of the stationary
die and the moving die are arranged to be shifted in phase in such
a manner that thread rolling is alternately carried out with
reciprocation of the ram 7. That is, the respective sets of the
flat die do not perform thread rolling at the same time but one of
the sets terminates thread rolling and performs returning action
when the other of the sets performs thread rolling. In other words,
one of the sets is located in the thread rolling terminating
position when the other of the sets is located in the thread
rolling beginning position. This suppresses deformation of the ram
7 caused by the thread rolling pressure at the time of thread
rolling and prevents degradation in thread rolling accuracy and an
increase in load on the motor.
[0018] The reference numerals 12, 13 denote part feeders, which
impart vibrations to bolt stocks being later on subjected to thread
rolling to successively align the bolt stocks having been regulated
in position to feed the same one by one to guide rails 14, 15 and
which are arranged on one side of the ram in the same manner as the
stationary die. The reference numerals 16, 17 denote projection
plates having tip ends thereof facing outlets of the guide rails
14, 15 and serving to feed the bolt stocks, having reached to the
outlets of the guide rails, between a set of the moving die 10a and
the stationary die 9a and a set of the moving die 10b and the
stationary die 9b, which are in a state prior to thread
rolling.
[0019] In addition, the reference numerals 18a, 18b denote upper
covers for preventing floating of the ram in a motion (advancing
motion), in which the connecting rod 6 pushes the ram 7 and for
adjusting sliding accuracy of the ram (the ram 7 moves while the
upper surface thereof is sliding on the inner surfaces of the upper
covers).
[0020] FIG. 2 shows another embodiment of the invention, in which
the part feeders 12, 13 disposed adjacent to each other in the
previous embodiment are disposed in somewhat spaced positions (the
other arrangement is the same as that shown in FIG. 1).
[0021] In the embodiments shown in FIGS. 1 and 2, the ram 7 is
single and lengthy. Thus the ram 7 is made single and lengthy, and
the single thread rolling pressure bearing block 11 is arranged on
the opposite surface of the ram 7 to a surface, on which the moving
dies 10a, 10b are mounted, whereby backward bending deformation of
the ram 7 at the time of thread rolling is prevented and accuracy
of threads manufactured in thread rolling can be kept high.
Meanwhile, since the ram is great in weight (in addition, the
weight increases as the number of sets of the dies increases), the
drive mechanism must have a larger capacity. Since the ram is large
in length (the relationship with the number of sets of the dies is
the same as the weight), it is necessary to pay attention to
maintaining machining accuracy of the ram. Also, since the ram is
small in specific surface area, it is necessary to pay attention to
favorable radiation of frictional heat.
[0022] The matters, to which attention is paid, in the embodiments
shown in FIGS. 1 and 2 are taken into account in an embodiment
shown in FIG. 3, in which the ram 7 is divided into two rams 7a, 7b
and the moving dies 10a, 10b, respectively, are arranged on the
respective rams (the respective rams are connected to each other by
a connecting member 8. The remaining construction is the same as
that shown in FIG. 1). However, it is necessary in this embodiment
to take measure of suppressing an increased backward bending
deformation of the rams, in particular, the ram 7a (for example,
strengthening of the upper cover 18a and strict adjustment of a
clearance between the ram and the upper cover).
[0023] In addition, as a measure to positively avoid influences
caused by floating of the ram at the time of advancement of the ram
(leftward motion in the figure), it is proposed that the ram 7a in
the embodiment shown in FIG. 3 be made a idle ram (on one side of
which the moving die 10a is not arranged and which is used as a
simple drive force transmitting member. Accordingly, the ram in
this embodiment is not required to have a length as long as that of
the ram 7a shown therein), and the remaining ram 7b be constructed
in the same manner as the ram 7 shown in FIG. 1 or FIG. 2 is, or
further divided like the rams 7a, 7b in the embodiment shown in
FIG. 3.
[0024] With the reciprocating type thread rolling apparatus thus
constructed, when bolt stocks are fed to the part feeders 12, 13
and the drive mechanism arranged on the base 2 is driven, the large
gear 5 is caused to start rotation through rotation of the pulley 3
and hence rotation of the small gear 4 mounted on the shaft of the
pulley. With rotation of the large gear 5, the connecting rod 6,
one end of which is pivoted in the eccentric position on the side
of the large gear, performs crank motion to reciprocate (rightward
and leftward movements in the figure) the ram 7, to which the other
end of the connecting rod is pivoted. Reciprocation of the ram
causes the moving dies 10a, 10b mounted on one side of the ram to
pair (10a and 9a; 10b and 9b) with the mating stationary dies 9a,
9b, so that the respective sets of the dies can alternately perform
thread rolling.
[0025] With the embodiments shown in FIGS. 1 and 3, the ram 7 is in
a most retreated position, the set of the stationary die 9a and the
moving die 10a on the right side being in a state, in which thread
rolling has been completed, and the set of the stationary die 9b
and the moving die 10b on the left side being in a thread rolling
start state, in which thread rolling can be performed when the ram
7 advances subsequently. Also, with the embodiment shown in FIG. 2,
the ram 7 is in a most advanced position, the set of the stationary
die 9a and the moving die 10a on the right side being in a state,
in which thread rolling has been completed, and the set of the
stationary die 9b and the moving die 10b on the left side being in
a thread rolling start state, in which thread rolling can be
performed when the ram 7 retreats subsequently. In this manner,
thread rolling can be performed at either of advancing and
retreating of the ram 7 by varying the relative positional
relationship between the stationary dies 9a, 9b and the moving dies
10a, 10b, and positions of the part feeders 12, 13, and thread
rolling of two bolt stocks can be simultaneously performed in one
stroke.
[0026] Also, thread rolling can preferably be performed at high
speed (productivity is two times a conventional one) when
anti-slipping serrations (not shown) are provided on that side of
thread formation surfaces of the stationary dies 9a, 9b and the
moving dies 10a, 10b, at which thread rolling is started, to
improve seizure of bolt stocks being subjected to thread rolling.
On the other hand, when speed of thread rolling is reduced to about
a half of a conventional one, bolt stocks can surely bite the dies
even without any serrations on the thread rolling starting side of
the thread formation surfaces, thus making it possible to
manufacture bolts with high accuracy and pretty threaded surfaces
as formed (in this case, the volume of production is approximately
the same as that in the prior art).
[0027] In addition, while the reciprocating type thread rolling
apparatus according to the invention has been described by way of a
bolt stock, it goes without saying that the reciprocating type
thread rolling apparatus according to the invention can apply
thread rolling on screws such as wood screws, tapping screws and
the like.
[0028] Also, in the case where a longitudinally oriented flat die
is used and a length of thread rolling is smaller than a half of a
width of the flat dies 9, 10, thread rolling can be again performed
at non-used portions by turning the worn dies 9, 10 upside down for
mounting, which doubles the life of the dies to enable achieving
cutting-down of cost for dies by half.
[0029] As described above, with the reciprocating type thread
rolling apparatus according to the invention, the ram adapted to be
reciprocated by the crank shaft is arranged along the single thread
rolling pressure bearing block and caused to slide on the side
surface of the thread rolling pressure bearing block, whereby
adequate rigidity can be ensured and thread rolling can be
performed at high accuracy. Also, the moving dies adapted to pair
with the stationary dies for thread rolling are arranged on the
same side of the ram, whereby the need of moving to an opposite
side at the time of setting-up is eliminated to make workability
favorable, and the need of providing a setting-up regulating space
on the opposite side is eliminated to enable making a work space
smaller than that in the prior art. Further, in the case where a
longitudinally oriented flat die is used and a length of thread
rolling is smaller than a half of a width of the flat die, thread
rolling can be again performed at non-used portions of the die by
turning the worn die upside down for mounting, which doubles the
life of the die to enable achieving cutting-down of cost for the
die by half.
* * * * *