Note: Descriptions are shown in the official language in which they were submitted.
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SPRING COILING MACHINE WITH IMPROV~D FEED ROLL DRIVE MEANS
BACKGROUND OF THE INVENTION
Prior art spring coiling machines fall into two general
categories - segment and clutch-type machines - with reference to
tne type of the feed roll drive mechanism incorporated in the
machine. Segment-type coilers are the more common and include
; a large oscillatory gear segment driving a feed roll gear train
with a unidirectional clutch for intermittent longitudinal wire
advancement to a coiling station. While coiling machines of this
type are characterized by a high degree of accuracy and depend-
ability in use, they are somewhat limited with regard to high
speed production. A relatively heavy and high inertia element
` such as a large gear segment has inherent limitations in increasing
the speed of operation of the machine. In a typical high volume
production operation automotive valve springs a}e produced on
segment-type coiling machines manufactured by the Torin Corporation
of Torrington, Connecticut, at a production rate of approximately
g0 springs per minute.
; In an attempt to improve the production rates of segment-
type spring coiling machines, a ~afios machine employs a larger
number of feed rolls than the conventional segment coiler ~ut the
rolls are of smaller size to reduce inertia and a light-t~eight
aluminum alloy segment is used in place of the conventional gray
iron and steel segment. This results in some reduction of inertia
forces and in a high volume valve spring operation as mentioned
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above the Wafios machine has achieved production ra~es of approxi-
mately 100 to 110 springs per minute.
Clutch-type spring coilers employ a clutch in place
of the segment for driving the feed rolls and are particularly
well adapted to applications where long wire feeds or even con-
tinuous wire feeding is required. Clutch-type machines may also
employ a continuous wire feed with a flying-cutoff device for
severing the individual springs. While relatively high rates of
production can be achieved, the accuracy of clutch machines cannot
match that of segment-type spring coiling machines and it is
' often necessary to reduce machine speed in order to obtain the
necessary accuracy and dependability in operation.
It is the general objeet of the present invention to
provide a spring colling machine having eam driven feed rolls and
which exhibits a high degree of accuraey and dependability in use
and an accompanying substantial improvement in the speed of
operation over that of segment-type spring coiling machinesO
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SUMMARY OF THE INVE:NTION
In fulfillment of the foregoing object, a cyclically
operable spring eoiling maehine is provided with a cam for operat-
ing feed roll drive gears and whieh is adapted for continuous
rotation. Cam actuated means ineluding a cam follower and an
operatively associated oscillable cam lever cooperate with a
drive and nneeting deviee between an output end porti n o' the
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cam lever and an input gear in a gear means for rotating the
wire feed rolls intermittently in a longitudinal wire advancing
direction. A unidirectional clutch is associated with the gear
means and the input gear is rotated in one and an opposite or
drive and return directions with the feed rolls operating only
in a drive direction. The cam in its continuous rotation causes
no significant problem in inertia reduction. The construction
and arrangement of the cam lever, connecting device, gear means
and feed rolls is directed to minimal inertia and high speed
machine operation. A wire feed length adjustment means operativel~
associated with the cam lever and/or connecting means is similarly
constructed and may be adapted for running adjustment of wire
feed length.
With the foregoing arrangement a substantial reduction
of inertial forces is achieved in reciprocating and ~oscillating
elements and a subs-tantial improvement in machine operating speed
realized. Further, the wire feeding portion of a machine cycle
in a segment machine is limited to about 230 or less depending
on the length of wire being fed. With a cam drive it is possible
to achieve approximately a 270 feed portion of a cycle with a
90 return portion for all wire lengths. The short return por-
; tion of the cycle is possible due to the low inertia characteris-
tics of reciprocating and oscillating elements and the absence
of any requirement for return of a relatively heavy segment. As
will be apparent, the ability to employ a larger portion of each
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~ cycle of machine operation in the wire feeding operation reduces
; wire velocity for a given wire length and a corresponding reduc-
tion occurs in inertial and coiling load, the latter referring to
reactive forces on the feed rolls resulting from the coiling
operation as well as loading on the coiling tool, etc. The
approximate 15% increase in the feed portion of the cycle results
in a considerable reduction in friction at the coiling tool.
~till further, it is possible to design highly desirable acceIera-
tion and deceleration characteristics into a cam. This is quite
difficult if not impossible to achieve with a conventional
segment drive where adjustments are limited to the relative posi-
tioning of a pivot point and a bull g~ar which drives the segment.
With the foregoing advantages of the cam drive, the
spring coiling machine of the present invention is capable of
producing 130 springs per minute in the above mentioned high
volume vaIve spring operation. Thus, approximately a 60% improve-
ment is achieved in the rate of production over that of a
conventional segment drive machine and yet the accuracy and the
: dependability of a segment drive machine is equaled if not ex-
ceeded.
- BRIEF DESCRIPTION OF THE DRAI~INGS
Fig. 1 is a somewhat schematic illustration of a spring
coiling machine viewed from the front and including the improved
feed roll cam drive of the present invention.
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Fig. 2 is an enlarged and somewhat schematic view
taken from the rear of the machine and illustrating the cam
drive means of the present invention in a first form.
Fig. 3 is a further enlarged and somewhat schematic
view similar to Fig. 2 illustrating the first form of the cam
drive means.
Fig. 4 is a schematic view similar to Fig. 2 but
illustrating a second embodiment of the cam drive means of the
,~ invent ion .
Fig. 5 is an enlarged vertical sectional view taken
through a ca~ lever and wire feed length adjustment means forming
a third embodiment of the invention.
Fig. 6 is a riyht-hand side view of the cam lever and
adjustment means of Fig. 5.
Fig. 7 is a generally horizontal sectional view taken
generally as indicated by the line 7-7 in Fig. 5.
i~ D CRIPTION OF PREFERRED EMBODIMENTS
Referring particularly to Fig. 1, it will be observed
that a spring coiling machine indicated generally at 10 has first
and second pairs of oppositely rotatable feed rolls 12, 14 and
16, 18 for advancing wire longitudinally to a coiling station
indicated generally at 20. In Fig. 1 the upper feed rolls 12, 16
rotate in a clockwise direction and the lower rolls 14, 18 in a
counterclockwise direction to feed wire 2Z leftwardly through
guides 24, 26, 28 for the formation of the wire into a coil spring
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configuration 30 at its leading end portion. The leading end
portions of the wire 22 are coiled about a coiling arbor 32 at
the coiling station 20, the arbor cooperating with a coiling
tool 34 at the station in the form of a coiling roll. The coiling
arbor 32 and tool 34 are fixed at the coiling station relative
to the wire so that longitudinally advancing wire engages the
tool 3~ and is obstructed in its linear movement thereby, the
wire thus being progressively bent about the arbor 32 with a
- coiling stress imparted thereto resulting in the formation of
the leading end coil spring configuration.
When the leading end portion of wire 22 has been bent
to a coil spring configuration above the arbor 32 it is severed
from the remaining portion of the wire 22 by means of a cutoff
; tool as indicated at 36, individual coil springs thus being
formed. Element 38 at the coiling station 20 may take the form of
a second cutoff tool or a pitch tool engageable with the wire
~ during coiling about the arbor 32 progressively to pitch the same
; as required for the coil spring to be formed.
As thus far described and illustrated schematlcally,
the spring coiling machine 10 is or may be conventional and for
further illustration and description of such a machine including
operating means for elements such as the cutoff tool 36 and pitch
tool 38 reference may be had to Bergevin and Nigro patent no.
2,119,002 for SPRING COILING M~CHINE, dated ~lay 3, 1938. The
machine shown and described in the patent, ho~ever, is of the
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segment drive type mentioned above and while highly accurate and
dependable in operation is limited as to its rate of spring pro-
duction.
The spring coiling machine of the present invention is
cyclically operable as in the case of the segment coiler of the
aforementioned patent and operates to intermittently advance wire
longitudinally leftwardly to the coiling station 20. As indicated,
the feed roll drive means in the machine of the present invention
is of the cam type rather than the segment type with resulting
operational and economic advantages. In Fig. 1, a drive motor
and speed reducer 40 are illustrated at a right-hand portion of
the machine, and in Fig. 2 an output pulley or sprocket 42 drives
. a pulley or sprocket 44 via a pulley or sprocket 46 associated
therewith. The pulley or sprocket 44 has a coaxial gear 48
lS rotatable therewith to drive a gear 50 in the counterclockwise
direction as illustrated in Fig. 2. The gear 50 has a coaxial
gear 52 in turn driving a gear 54 in a clockwise direction and
serving to rotate the gear 56 on a shaft 58 in a counterclockwise
direction. Thus, the shaft 58 is power driven for continuous
rotation and may hereafter be referred to as a power driven
; cam shaft, the shaft also carrying a cam 60 which is a principal
erement in a feed roll drive means of the present invention.
The cam 60 includes a track 62 partially illustrated
in Fig. 3 and which has an associated follower 64 at a lower end
portion of a cam lever 66. The cam lever 66 is oscillable in
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Fig. 3 about a pivot shaft 68 and carries at an upper or free end
portion thereof a slide 70. The slide 70 in turn operates a
drive and connecting device 72 for a pinion gear 74, an input
gear in a feed roll drive means. As will be described herein-
below, the slide 70 also forms a part of a wire feed length adjust-
ment means operatively associated with the cam lever 66 and the
drive and connecting device 72 and which may be a part of either
or both of said elements.
Returning now to Fig. 2, it will be observed that the
input or pinion gear 74 is mounted on a shaft 76 and also drives
a larger gear 78 for driving feed roll gears 80, 82, 84 and 86.
A unidirectional or ;ndex clutch is also a part of the feed roll
drive gear means and may be~ffls~ntcd on ~he-~hQft-7~ between the pi~ _
ion gear 74 and the larger gear 78~. Thus, the feed rolls may be
operated to rotate in a drive or wire feeding direction and to
remain stationary in a return direction o elements including
the gear 74, the drive and connecting device 72, the cam lever
66 and follower 64. As illustrated in Fig. 2, gears 80, 82
respectively drive feed rolls 14, 12 and gears 84, 86 respectively
drive feed rolls 16, 18. The drive or feed direction of gear
and roll rotation is indicated by small arrows in Figs. 1 and 2.
Reverting to Fig. 3, the drive and connecting device
72 preferably comprises a rack assembly including a rac~ gear 88
on a reciprocable link 90 pivotally connected at a right-hand
end portion 92 to the slide 70. A housing 94 mounted on the
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hub of gear 74 is rotatable through at least a limited arc and
. slldably receives the link and/or rack gear 88. Thus, the action
of the link 90 and rack gear 88 is not precisely linear but tends
to the oscillatory with the link slidable in the swingable housing
94 and with ball or roller bearings 96 provided in the housing for
: free sliding action.
~;~ As will be apparent, cam induced oscillation of the
. follower 64 relative to the cam or drive shaft 58 will result
in oscillatory movement of the lever 66 about i-ts pivot shaft
68, reciprocable or slightly oscillatory movement of the link 90
~ and in rotation of the pinion or input gear 74 in one and an
: opposite direction by the rack gear 88. The small arrows in Fig.
2 indicate such movement in a drive or wire feeding direction
with a return or inoperative movement of course occurring in an
opposite direction. As mentioned above, the rotation of the cam
60 may be continuous with reciprocating and/or oscillating move-
ment occurring between the cam and the feed rolls 12-18, the
unidirectional clutch on the shaft 76 serving to terminate feed
roll rotation at the end o~ a wire advancing or feeding portion
of the machine cycle. As mentioned, a portion of the cycle as
hi~h as 270 can be employed for feeding wire with the cam driven
~eed roll arrangement of the present invention. As illustrated,
the machine is designed for a limited range of wire feed lengths
particularly well suited to the automotive valve spring operation
mentioned above, that is, a 10 to 40 inch variation or adjustment
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in wire feed.
The wire feed length adjustment means of the invention
includes the slide 70 as mentioned and a means for moving the
slide in one and an opposite direction along the length of the
lever 66 and for fixing the slide in a desired position of adjust-
ment. As illustrated in Fig. 3, a lead screw 98 is associated
with the slide 70 and has an end portion thereof secured in the-
body of the lever 66 at 100. Rotation of the lead screw serves
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to ad~ust the position of the slide 70 along the lever 66 and
a fixing or binding screw 102 serves to secure the slide in
adjusted position along the lever. Thus, a maximum throw is
provided for the oscillable lever 66 with the slide 70 positioned
at its extreme outward limit as illustrated. As the slide is
adjusted inwardly or downwardly along the length of the cam lever
lesser wire feed lengths are provided for as desired.
Whilè the machine illustrated is limited as stated
~ with regard to the range of wire feed, it is to be understood
,~ that various other ranges of wire feed length can be readily
` provided for by substituting cams of suitable design for the cam
60. Further, and with regard to inertia reduction and high speed
machine operation, it should be observed that each of the recipro-
cating and/or oscillating elements is constructed and arranged
to provide for minimum weight and inertial conditions. The
cam 60 and/or substitute cams has an inherent capability for
adjustment and selection of desired acceleration and deceleration
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characteristiCS of the feed rolls. Presently under consideration
are a cycloidal acceleration characteristic for a wire feeding
operation o~ the feed rolls. The return movement of the cam
may be a second or third harmonic motion. Also under considera-
tion are third harmonic forward and return motions as well asa modified sine characteristic for acceleration.
In Fig. 4, a second form of the feed roll drive means
of the present invention is illustrated and includes a linearly
reciprocable rack 88a driving a pinion gear 74a. The rack 88a
is driven by a connecting link 90a having a pivotal connection
therewith at 104, Cam lever 60a has a pivot shaft at 106 and
a follower at 64a cooperating with an externally configured cam
60a. The construction and arrangement of the spring coiling
machine may be otherwise identical with that illustrated and
described above.
Figs. 5-7 illustrate a wire feed length adjustment
means capable of running operation i.e., adjustable while the
spring coiling machine is in operation. A cam lever 66b is
substantially identical with the lever 66 and has an associated
slide 70b moved longitudinally of the lever by means of a lead
screw 98b. The lead screw 98b, at a lower or inner end portion
is power operated from a small motcr 108 which may comprise a
motor of the air or hydraulic type e.g., a Gardner air motor or
a Lamina Company hydraulic motor. A lock-up or position fixing
device for the slide 70b may take the form of a small FAB Co.
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pancake cylinder, air or hydraulic, indicated at 110. The small
lock-up cylinder 110 is mounted on a bracket 112 secured as by
suitable screws 114, 114 to the slide 70b and having an output
member 116 frictionally engageable with a rear portion 118 of
the cam lever. As will be apparent, the member 116 is withdrawn
or at least released on the member 118 during longitudinal adjust-
ment of the slide 70b relative to the cam lever 66b, the motor
; 108 serving to effect such adjustment as required. When the
l desired position of the slide 70b along the lever 66b has been
-; 10 reached, the pancake cylinder 110 is energized to urge the binder
or frictional member or pin 116 into firm engagement with the
lever portion 118 and to secure the slide in adjusted position.
As will be observed, the motor 108 is located in close
proximity to the pivot shaft 68a to minimize inertial forces
during oscillation of the cam lever 66b. The motor is also of
minimal weight and size as is the lock-up cylinder 110. The
lock-up cylinder 110 must of necessity be located outwardly along
the lever 66b but its minimal weight avoids any serious inertia
problems.
From the foregoing it will apparent that the various
features of the feed roll drive means of the present invention
cooperatively provide a highly accurate and high speed spring
coiling machine. The heaviest and highest inertia element in the
drive means in the form of the cam is rotated continuously while
~all element between the cam and the unidirectional clutch are
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:1 designed for a minimal inertia. The ability of the cam drive
: means to employ a 270 feed portion of the machine cycle further
contributes to efficient high speed operation as does the ability
of the cam to provide desired acceleration and deceleration char-
: 5 acteristics of the feed rolls and other elements driven thereby.As indicated, the resulting production rates of 130 valve springs
per minute present a substantial imp~ovement in machine speed.
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